// SPDX-License-Identifier: GPL-2.0 /* * Shared application/kernel submission and completion ring pairs, for * supporting fast/efficient IO. * * A note on the read/write ordering memory barriers that are matched between * the application and kernel side. * * After the application reads the CQ ring tail, it must use an * appropriate smp_rmb() to pair with the smp_wmb() the kernel uses * before writing the tail (using smp_load_acquire to read the tail will * do). It also needs a smp_mb() before updating CQ head (ordering the * entry load(s) with the head store), pairing with an implicit barrier * through a control-dependency in io_get_cqring (smp_store_release to * store head will do). Failure to do so could lead to reading invalid * CQ entries. * * Likewise, the application must use an appropriate smp_wmb() before * writing the SQ tail (ordering SQ entry stores with the tail store), * which pairs with smp_load_acquire in io_get_sqring (smp_store_release * to store the tail will do). And it needs a barrier ordering the SQ * head load before writing new SQ entries (smp_load_acquire to read * head will do). * * When using the SQ poll thread (IORING_SETUP_SQPOLL), the application * needs to check the SQ flags for IORING_SQ_NEED_WAKEUP *after* * updating the SQ tail; a full memory barrier smp_mb() is needed * between. * * Also see the examples in the liburing library: * * git://git.kernel.dk/liburing * * io_uring also uses READ/WRITE_ONCE() for _any_ store or load that happens * from data shared between the kernel and application. This is done both * for ordering purposes, but also to ensure that once a value is loaded from * data that the application could potentially modify, it remains stable. * * Copyright (C) 2018-2019 Jens Axboe * Copyright (c) 2018-2019 Christoph Hellwig */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define CREATE_TRACE_POINTS #include #include #include "internal.h" #include "io-wq.h" #define IORING_MAX_ENTRIES 32768 #define IORING_MAX_CQ_ENTRIES (2 * IORING_MAX_ENTRIES) /* * Shift of 9 is 512 entries, or exactly one page on 64-bit archs */ #define IORING_FILE_TABLE_SHIFT 9 #define IORING_MAX_FILES_TABLE (1U << IORING_FILE_TABLE_SHIFT) #define IORING_FILE_TABLE_MASK (IORING_MAX_FILES_TABLE - 1) #define IORING_MAX_FIXED_FILES (64 * IORING_MAX_FILES_TABLE) struct io_uring { u32 head ____cacheline_aligned_in_smp; u32 tail ____cacheline_aligned_in_smp; }; /* * This data is shared with the application through the mmap at offsets * IORING_OFF_SQ_RING and IORING_OFF_CQ_RING. * * The offsets to the member fields are published through struct * io_sqring_offsets when calling io_uring_setup. */ struct io_rings { /* * Head and tail offsets into the ring; the offsets need to be * masked to get valid indices. * * The kernel controls head of the sq ring and the tail of the cq ring, * and the application controls tail of the sq ring and the head of the * cq ring. */ struct io_uring sq, cq; /* * Bitmasks to apply to head and tail offsets (constant, equals * ring_entries - 1) */ u32 sq_ring_mask, cq_ring_mask; /* Ring sizes (constant, power of 2) */ u32 sq_ring_entries, cq_ring_entries; /* * Number of invalid entries dropped by the kernel due to * invalid index stored in array * * Written by the kernel, shouldn't be modified by the * application (i.e. get number of "new events" by comparing to * cached value). * * After a new SQ head value was read by the application this * counter includes all submissions that were dropped reaching * the new SQ head (and possibly more). */ u32 sq_dropped; /* * Runtime SQ flags * * Written by the kernel, shouldn't be modified by the * application. * * The application needs a full memory barrier before checking * for IORING_SQ_NEED_WAKEUP after updating the sq tail. */ u32 sq_flags; /* * Runtime CQ flags * * Written by the application, shouldn't be modified by the * kernel. */ u32 cq_flags; /* * Number of completion events lost because the queue was full; * this should be avoided by the application by making sure * there are not more requests pending than there is space in * the completion queue. * * Written by the kernel, shouldn't be modified by the * application (i.e. get number of "new events" by comparing to * cached value). * * As completion events come in out of order this counter is not * ordered with any other data. */ u32 cq_overflow; /* * Ring buffer of completion events. * * The kernel writes completion events fresh every time they are * produced, so the application is allowed to modify pending * entries. */ struct io_uring_cqe cqes[] ____cacheline_aligned_in_smp; }; struct io_mapped_ubuf { u64 ubuf; size_t len; struct bio_vec *bvec; unsigned int nr_bvecs; }; struct fixed_file_table { struct file **files; }; struct fixed_file_ref_node { struct percpu_ref refs; struct list_head node; struct list_head file_list; struct fixed_file_data *file_data; struct llist_node llist; }; struct fixed_file_data { struct fixed_file_table *table; struct io_ring_ctx *ctx; struct percpu_ref *cur_refs; struct percpu_ref refs; struct completion done; struct list_head ref_list; spinlock_t lock; }; struct io_buffer { struct list_head list; __u64 addr; __s32 len; __u16 bid; }; struct io_ring_ctx { struct { struct percpu_ref refs; } ____cacheline_aligned_in_smp; struct { unsigned int flags; unsigned int compat: 1; unsigned int limit_mem: 1; unsigned int cq_overflow_flushed: 1; unsigned int drain_next: 1; unsigned int eventfd_async: 1; /* * Ring buffer of indices into array of io_uring_sqe, which is * mmapped by the application using the IORING_OFF_SQES offset. * * This indirection could e.g. be used to assign fixed * io_uring_sqe entries to operations and only submit them to * the queue when needed. * * The kernel modifies neither the indices array nor the entries * array. */ u32 *sq_array; unsigned cached_sq_head; unsigned sq_entries; unsigned sq_mask; unsigned sq_thread_idle; unsigned cached_sq_dropped; atomic_t cached_cq_overflow; unsigned long sq_check_overflow; struct list_head defer_list; struct list_head timeout_list; struct list_head cq_overflow_list; wait_queue_head_t inflight_wait; struct io_uring_sqe *sq_sqes; } ____cacheline_aligned_in_smp; struct io_rings *rings; /* IO offload */ struct io_wq *io_wq; struct task_struct *sqo_thread; /* if using sq thread polling */ struct mm_struct *sqo_mm; wait_queue_head_t sqo_wait; /* * If used, fixed file set. Writers must ensure that ->refs is dead, * readers must ensure that ->refs is alive as long as the file* is * used. Only updated through io_uring_register(2). */ struct fixed_file_data *file_data; unsigned nr_user_files; int ring_fd; struct file *ring_file; /* if used, fixed mapped user buffers */ unsigned nr_user_bufs; struct io_mapped_ubuf *user_bufs; struct user_struct *user; const struct cred *creds; struct completion ref_comp; struct completion sq_thread_comp; /* if all else fails... */ struct io_kiocb *fallback_req; #if defined(CONFIG_UNIX) struct socket *ring_sock; #endif struct idr io_buffer_idr; struct idr personality_idr; struct { unsigned cached_cq_tail; unsigned cq_entries; unsigned cq_mask; atomic_t cq_timeouts; unsigned long cq_check_overflow; struct wait_queue_head cq_wait; struct fasync_struct *cq_fasync; struct eventfd_ctx *cq_ev_fd; } ____cacheline_aligned_in_smp; struct { struct mutex uring_lock; wait_queue_head_t wait; } ____cacheline_aligned_in_smp; struct { spinlock_t completion_lock; /* * ->iopoll_list is protected by the ctx->uring_lock for * io_uring instances that don't use IORING_SETUP_SQPOLL. * For SQPOLL, only the single threaded io_sq_thread() will * manipulate the list, hence no extra locking is needed there. */ struct list_head iopoll_list; struct hlist_head *cancel_hash; unsigned cancel_hash_bits; bool poll_multi_file; spinlock_t inflight_lock; struct list_head inflight_list; } ____cacheline_aligned_in_smp; struct delayed_work file_put_work; struct llist_head file_put_llist; struct work_struct exit_work; }; /* * First field must be the file pointer in all the * iocb unions! See also 'struct kiocb' in */ struct io_poll_iocb { struct file *file; union { struct wait_queue_head *head; u64 addr; }; __poll_t events; bool done; bool canceled; struct wait_queue_entry wait; }; struct io_close { struct file *file; struct file *put_file; int fd; }; struct io_timeout_data { struct io_kiocb *req; struct hrtimer timer; struct timespec64 ts; enum hrtimer_mode mode; }; struct io_accept { struct file *file; struct sockaddr __user *addr; int __user *addr_len; int flags; unsigned long nofile; }; struct io_sync { struct file *file; loff_t len; loff_t off; int flags; int mode; }; struct io_cancel { struct file *file; u64 addr; }; struct io_timeout { struct file *file; u64 addr; int flags; u32 off; u32 target_seq; struct list_head list; }; struct io_rw { /* NOTE: kiocb has the file as the first member, so don't do it here */ struct kiocb kiocb; u64 addr; u64 len; }; struct io_connect { struct file *file; struct sockaddr __user *addr; int addr_len; }; struct io_sr_msg { struct file *file; union { struct user_msghdr __user *umsg; void __user *buf; }; int msg_flags; int bgid; size_t len; struct io_buffer *kbuf; }; struct io_open { struct file *file; int dfd; struct filename *filename; struct open_how how; unsigned long nofile; }; struct io_files_update { struct file *file; u64 arg; u32 nr_args; u32 offset; }; struct io_fadvise { struct file *file; u64 offset; u32 len; u32 advice; }; struct io_madvise { struct file *file; u64 addr; u32 len; u32 advice; }; struct io_epoll { struct file *file; int epfd; int op; int fd; struct epoll_event event; }; struct io_splice { struct file *file_out; struct file *file_in; loff_t off_out; loff_t off_in; u64 len; unsigned int flags; }; struct io_provide_buf { struct file *file; __u64 addr; __s32 len; __u32 bgid; __u16 nbufs; __u16 bid; }; struct io_statx { struct file *file; int dfd; unsigned int mask; unsigned int flags; const char __user *filename; struct statx __user *buffer; }; struct io_completion { struct file *file; struct list_head list; int cflags; }; struct io_async_connect { struct sockaddr_storage address; }; struct io_async_msghdr { struct iovec fast_iov[UIO_FASTIOV]; struct iovec *iov; struct sockaddr __user *uaddr; struct msghdr msg; struct sockaddr_storage addr; }; struct io_async_rw { struct iovec fast_iov[UIO_FASTIOV]; const struct iovec *free_iovec; struct iov_iter iter; size_t bytes_done; struct wait_page_queue wpq; }; struct io_async_ctx { union { struct io_async_rw rw; struct io_async_msghdr msg; struct io_async_connect connect; struct io_timeout_data timeout; }; }; enum { REQ_F_FIXED_FILE_BIT = IOSQE_FIXED_FILE_BIT, REQ_F_IO_DRAIN_BIT = IOSQE_IO_DRAIN_BIT, REQ_F_LINK_BIT = IOSQE_IO_LINK_BIT, REQ_F_HARDLINK_BIT = IOSQE_IO_HARDLINK_BIT, REQ_F_FORCE_ASYNC_BIT = IOSQE_ASYNC_BIT, REQ_F_BUFFER_SELECT_BIT = IOSQE_BUFFER_SELECT_BIT, REQ_F_LINK_HEAD_BIT, REQ_F_FAIL_LINK_BIT, REQ_F_INFLIGHT_BIT, REQ_F_CUR_POS_BIT, REQ_F_NOWAIT_BIT, REQ_F_LINK_TIMEOUT_BIT, REQ_F_ISREG_BIT, REQ_F_COMP_LOCKED_BIT, REQ_F_NEED_CLEANUP_BIT, REQ_F_POLLED_BIT, REQ_F_BUFFER_SELECTED_BIT, REQ_F_NO_FILE_TABLE_BIT, REQ_F_WORK_INITIALIZED_BIT, REQ_F_TASK_PINNED_BIT, /* not a real bit, just to check we're not overflowing the space */ __REQ_F_LAST_BIT, }; enum { /* ctx owns file */ REQ_F_FIXED_FILE = BIT(REQ_F_FIXED_FILE_BIT), /* drain existing IO first */ REQ_F_IO_DRAIN = BIT(REQ_F_IO_DRAIN_BIT), /* linked sqes */ REQ_F_LINK = BIT(REQ_F_LINK_BIT), /* doesn't sever on completion < 0 */ REQ_F_HARDLINK = BIT(REQ_F_HARDLINK_BIT), /* IOSQE_ASYNC */ REQ_F_FORCE_ASYNC = BIT(REQ_F_FORCE_ASYNC_BIT), /* IOSQE_BUFFER_SELECT */ REQ_F_BUFFER_SELECT = BIT(REQ_F_BUFFER_SELECT_BIT), /* head of a link */ REQ_F_LINK_HEAD = BIT(REQ_F_LINK_HEAD_BIT), /* fail rest of links */ REQ_F_FAIL_LINK = BIT(REQ_F_FAIL_LINK_BIT), /* on inflight list */ REQ_F_INFLIGHT = BIT(REQ_F_INFLIGHT_BIT), /* read/write uses file position */ REQ_F_CUR_POS = BIT(REQ_F_CUR_POS_BIT), /* must not punt to workers */ REQ_F_NOWAIT = BIT(REQ_F_NOWAIT_BIT), /* has linked timeout */ REQ_F_LINK_TIMEOUT = BIT(REQ_F_LINK_TIMEOUT_BIT), /* regular file */ REQ_F_ISREG = BIT(REQ_F_ISREG_BIT), /* completion under lock */ REQ_F_COMP_LOCKED = BIT(REQ_F_COMP_LOCKED_BIT), /* needs cleanup */ REQ_F_NEED_CLEANUP = BIT(REQ_F_NEED_CLEANUP_BIT), /* already went through poll handler */ REQ_F_POLLED = BIT(REQ_F_POLLED_BIT), /* buffer already selected */ REQ_F_BUFFER_SELECTED = BIT(REQ_F_BUFFER_SELECTED_BIT), /* doesn't need file table for this request */ REQ_F_NO_FILE_TABLE = BIT(REQ_F_NO_FILE_TABLE_BIT), /* io_wq_work is initialized */ REQ_F_WORK_INITIALIZED = BIT(REQ_F_WORK_INITIALIZED_BIT), /* req->task is refcounted */ REQ_F_TASK_PINNED = BIT(REQ_F_TASK_PINNED_BIT), }; struct async_poll { struct io_poll_iocb poll; struct io_poll_iocb *double_poll; }; /* * NOTE! Each of the iocb union members has the file pointer * as the first entry in their struct definition. So you can * access the file pointer through any of the sub-structs, * or directly as just 'ki_filp' in this struct. */ struct io_kiocb { union { struct file *file; struct io_rw rw; struct io_poll_iocb poll; struct io_accept accept; struct io_sync sync; struct io_cancel cancel; struct io_timeout timeout; struct io_connect connect; struct io_sr_msg sr_msg; struct io_open open; struct io_close close; struct io_files_update files_update; struct io_fadvise fadvise; struct io_madvise madvise; struct io_epoll epoll; struct io_splice splice; struct io_provide_buf pbuf; struct io_statx statx; /* use only after cleaning per-op data, see io_clean_op() */ struct io_completion compl; }; struct io_async_ctx *io; u8 opcode; /* polled IO has completed */ u8 iopoll_completed; u16 buf_index; u32 result; struct io_ring_ctx *ctx; unsigned int flags; refcount_t refs; struct task_struct *task; u64 user_data; struct list_head link_list; /* * 1. used with ctx->iopoll_list with reads/writes * 2. to track reqs with ->files (see io_op_def::file_table) */ struct list_head inflight_entry; struct percpu_ref *fixed_file_refs; struct callback_head task_work; /* for polled requests, i.e. IORING_OP_POLL_ADD and async armed poll */ struct hlist_node hash_node; struct async_poll *apoll; struct io_wq_work work; }; struct io_defer_entry { struct list_head list; struct io_kiocb *req; u32 seq; }; #define IO_IOPOLL_BATCH 8 struct io_comp_state { unsigned int nr; struct list_head list; struct io_ring_ctx *ctx; }; struct io_submit_state { struct blk_plug plug; /* * io_kiocb alloc cache */ void *reqs[IO_IOPOLL_BATCH]; unsigned int free_reqs; /* * Batch completion logic */ struct io_comp_state comp; /* * File reference cache */ struct file *file; unsigned int fd; unsigned int has_refs; unsigned int ios_left; }; struct io_op_def { /* needs req->io allocated for deferral/async */ unsigned async_ctx : 1; /* needs current->mm setup, does mm access */ unsigned needs_mm : 1; /* needs req->file assigned */ unsigned needs_file : 1; /* don't fail if file grab fails */ unsigned needs_file_no_error : 1; /* hash wq insertion if file is a regular file */ unsigned hash_reg_file : 1; /* unbound wq insertion if file is a non-regular file */ unsigned unbound_nonreg_file : 1; /* opcode is not supported by this kernel */ unsigned not_supported : 1; /* needs file table */ unsigned file_table : 1; /* needs ->fs */ unsigned needs_fs : 1; /* set if opcode supports polled "wait" */ unsigned pollin : 1; unsigned pollout : 1; /* op supports buffer selection */ unsigned buffer_select : 1; unsigned needs_fsize : 1; }; static const struct io_op_def io_op_defs[] = { [IORING_OP_NOP] = {}, [IORING_OP_READV] = { .async_ctx = 1, .needs_mm = 1, .needs_file = 1, .unbound_nonreg_file = 1, .pollin = 1, .buffer_select = 1, }, [IORING_OP_WRITEV] = { .async_ctx = 1, .needs_mm = 1, .needs_file = 1, .hash_reg_file = 1, .unbound_nonreg_file = 1, .pollout = 1, .needs_fsize = 1, }, [IORING_OP_FSYNC] = { .needs_file = 1, }, [IORING_OP_READ_FIXED] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollin = 1, }, [IORING_OP_WRITE_FIXED] = { .needs_file = 1, .hash_reg_file = 1, .unbound_nonreg_file = 1, .pollout = 1, .needs_fsize = 1, }, [IORING_OP_POLL_ADD] = { .needs_file = 1, .unbound_nonreg_file = 1, }, [IORING_OP_POLL_REMOVE] = {}, [IORING_OP_SYNC_FILE_RANGE] = { .needs_file = 1, }, [IORING_OP_SENDMSG] = { .async_ctx = 1, .needs_mm = 1, .needs_file = 1, .unbound_nonreg_file = 1, .needs_fs = 1, .pollout = 1, }, [IORING_OP_RECVMSG] = { .async_ctx = 1, .needs_mm = 1, .needs_file = 1, .unbound_nonreg_file = 1, .needs_fs = 1, .pollin = 1, .buffer_select = 1, }, [IORING_OP_TIMEOUT] = { .async_ctx = 1, .needs_mm = 1, }, [IORING_OP_TIMEOUT_REMOVE] = {}, [IORING_OP_ACCEPT] = { .needs_mm = 1, .needs_file = 1, .unbound_nonreg_file = 1, .file_table = 1, .pollin = 1, }, [IORING_OP_ASYNC_CANCEL] = {}, [IORING_OP_LINK_TIMEOUT] = { .async_ctx = 1, .needs_mm = 1, }, [IORING_OP_CONNECT] = { .async_ctx = 1, .needs_mm = 1, .needs_file = 1, .unbound_nonreg_file = 1, .pollout = 1, }, [IORING_OP_FALLOCATE] = { .needs_file = 1, .needs_fsize = 1, }, [IORING_OP_OPENAT] = { .file_table = 1, .needs_fs = 1, }, [IORING_OP_CLOSE] = { .needs_file = 1, .needs_file_no_error = 1, .file_table = 1, }, [IORING_OP_FILES_UPDATE] = { .needs_mm = 1, .file_table = 1, }, [IORING_OP_STATX] = { .needs_mm = 1, .needs_fs = 1, .file_table = 1, }, [IORING_OP_READ] = { .needs_mm = 1, .needs_file = 1, .unbound_nonreg_file = 1, .pollin = 1, .buffer_select = 1, }, [IORING_OP_WRITE] = { .needs_mm = 1, .needs_file = 1, .unbound_nonreg_file = 1, .pollout = 1, .needs_fsize = 1, }, [IORING_OP_FADVISE] = { .needs_file = 1, }, [IORING_OP_MADVISE] = { .needs_mm = 1, }, [IORING_OP_SEND] = { .needs_mm = 1, .needs_file = 1, .unbound_nonreg_file = 1, .pollout = 1, }, [IORING_OP_RECV] = { .needs_mm = 1, .needs_file = 1, .unbound_nonreg_file = 1, .pollin = 1, .buffer_select = 1, }, [IORING_OP_OPENAT2] = { .file_table = 1, .needs_fs = 1, }, [IORING_OP_EPOLL_CTL] = { .unbound_nonreg_file = 1, .file_table = 1, }, [IORING_OP_SPLICE] = { .needs_file = 1, .hash_reg_file = 1, .unbound_nonreg_file = 1, }, [IORING_OP_PROVIDE_BUFFERS] = {}, [IORING_OP_REMOVE_BUFFERS] = {}, [IORING_OP_TEE] = { .needs_file = 1, .hash_reg_file = 1, .unbound_nonreg_file = 1, }, }; enum io_mem_account { ACCT_LOCKED, ACCT_PINNED, }; static void __io_complete_rw(struct io_kiocb *req, long res, long res2, struct io_comp_state *cs); static void io_cqring_fill_event(struct io_kiocb *req, long res); static void io_put_req(struct io_kiocb *req); static void io_double_put_req(struct io_kiocb *req); static void __io_double_put_req(struct io_kiocb *req); static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req); static void __io_queue_linked_timeout(struct io_kiocb *req); static void io_queue_linked_timeout(struct io_kiocb *req); static int __io_sqe_files_update(struct io_ring_ctx *ctx, struct io_uring_files_update *ip, unsigned nr_args); static int io_prep_work_files(struct io_kiocb *req); static void __io_clean_op(struct io_kiocb *req); static int io_file_get(struct io_submit_state *state, struct io_kiocb *req, int fd, struct file **out_file, bool fixed); static void __io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe, struct io_comp_state *cs); static void io_file_put_work(struct work_struct *work); static ssize_t io_import_iovec(int rw, struct io_kiocb *req, struct iovec **iovec, struct iov_iter *iter, bool needs_lock); static int io_setup_async_rw(struct io_kiocb *req, const struct iovec *iovec, const struct iovec *fast_iov, struct iov_iter *iter, bool force); static struct kmem_cache *req_cachep; static const struct file_operations io_uring_fops; struct sock *io_uring_get_socket(struct file *file) { #if defined(CONFIG_UNIX) if (file->f_op == &io_uring_fops) { struct io_ring_ctx *ctx = file->private_data; return ctx->ring_sock->sk; } #endif return NULL; } EXPORT_SYMBOL(io_uring_get_socket); static void io_get_req_task(struct io_kiocb *req) { if (req->flags & REQ_F_TASK_PINNED) return; get_task_struct(req->task); req->flags |= REQ_F_TASK_PINNED; } static inline void io_clean_op(struct io_kiocb *req) { if (req->flags & (REQ_F_NEED_CLEANUP | REQ_F_BUFFER_SELECTED | REQ_F_INFLIGHT)) __io_clean_op(req); } /* not idempotent -- it doesn't clear REQ_F_TASK_PINNED */ static void __io_put_req_task(struct io_kiocb *req) { if (req->flags & REQ_F_TASK_PINNED) put_task_struct(req->task); } static void io_sq_thread_drop_mm(void) { struct mm_struct *mm = current->mm; if (mm) { kthread_unuse_mm(mm); mmput(mm); } } static int __io_sq_thread_acquire_mm(struct io_ring_ctx *ctx) { if (!current->mm) { if (unlikely(!(ctx->flags & IORING_SETUP_SQPOLL) || !mmget_not_zero(ctx->sqo_mm))) return -EFAULT; kthread_use_mm(ctx->sqo_mm); } return 0; } static int io_sq_thread_acquire_mm(struct io_ring_ctx *ctx, struct io_kiocb *req) { if (!io_op_defs[req->opcode].needs_mm) return 0; return __io_sq_thread_acquire_mm(ctx); } static inline void req_set_fail_links(struct io_kiocb *req) { if ((req->flags & (REQ_F_LINK | REQ_F_HARDLINK)) == REQ_F_LINK) req->flags |= REQ_F_FAIL_LINK; } /* * Note: must call io_req_init_async() for the first time you * touch any members of io_wq_work. */ static inline void io_req_init_async(struct io_kiocb *req) { if (req->flags & REQ_F_WORK_INITIALIZED) return; memset(&req->work, 0, sizeof(req->work)); req->flags |= REQ_F_WORK_INITIALIZED; } static inline bool io_async_submit(struct io_ring_ctx *ctx) { return ctx->flags & IORING_SETUP_SQPOLL; } static void io_ring_ctx_ref_free(struct percpu_ref *ref) { struct io_ring_ctx *ctx = container_of(ref, struct io_ring_ctx, refs); complete(&ctx->ref_comp); } static inline bool io_is_timeout_noseq(struct io_kiocb *req) { return !req->timeout.off; } static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) { struct io_ring_ctx *ctx; int hash_bits; ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); if (!ctx) return NULL; ctx->fallback_req = kmem_cache_alloc(req_cachep, GFP_KERNEL); if (!ctx->fallback_req) goto err; /* * Use 5 bits less than the max cq entries, that should give us around * 32 entries per hash list if totally full and uniformly spread. */ hash_bits = ilog2(p->cq_entries); hash_bits -= 5; if (hash_bits <= 0) hash_bits = 1; ctx->cancel_hash_bits = hash_bits; ctx->cancel_hash = kmalloc((1U << hash_bits) * sizeof(struct hlist_head), GFP_KERNEL); if (!ctx->cancel_hash) goto err; __hash_init(ctx->cancel_hash, 1U << hash_bits); if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free, PERCPU_REF_ALLOW_REINIT, GFP_KERNEL)) goto err; ctx->flags = p->flags; init_waitqueue_head(&ctx->sqo_wait); init_waitqueue_head(&ctx->cq_wait); INIT_LIST_HEAD(&ctx->cq_overflow_list); init_completion(&ctx->ref_comp); init_completion(&ctx->sq_thread_comp); idr_init(&ctx->io_buffer_idr); idr_init(&ctx->personality_idr); mutex_init(&ctx->uring_lock); init_waitqueue_head(&ctx->wait); spin_lock_init(&ctx->completion_lock); INIT_LIST_HEAD(&ctx->iopoll_list); INIT_LIST_HEAD(&ctx->defer_list); INIT_LIST_HEAD(&ctx->timeout_list); init_waitqueue_head(&ctx->inflight_wait); spin_lock_init(&ctx->inflight_lock); INIT_LIST_HEAD(&ctx->inflight_list); INIT_DELAYED_WORK(&ctx->file_put_work, io_file_put_work); init_llist_head(&ctx->file_put_llist); return ctx; err: if (ctx->fallback_req) kmem_cache_free(req_cachep, ctx->fallback_req); kfree(ctx->cancel_hash); kfree(ctx); return NULL; } static bool req_need_defer(struct io_kiocb *req, u32 seq) { if (unlikely(req->flags & REQ_F_IO_DRAIN)) { struct io_ring_ctx *ctx = req->ctx; return seq != ctx->cached_cq_tail + atomic_read(&ctx->cached_cq_overflow); } return false; } static void __io_commit_cqring(struct io_ring_ctx *ctx) { struct io_rings *rings = ctx->rings; /* order cqe stores with ring update */ smp_store_release(&rings->cq.tail, ctx->cached_cq_tail); if (wq_has_sleeper(&ctx->cq_wait)) { wake_up_interruptible(&ctx->cq_wait); kill_fasync(&ctx->cq_fasync, SIGIO, POLL_IN); } } /* * Returns true if we need to defer file table putting. This can only happen * from the error path with REQ_F_COMP_LOCKED set. */ static bool io_req_clean_work(struct io_kiocb *req) { if (!(req->flags & REQ_F_WORK_INITIALIZED)) return false; req->flags &= ~REQ_F_WORK_INITIALIZED; if (req->work.mm) { mmdrop(req->work.mm); req->work.mm = NULL; } if (req->work.creds) { put_cred(req->work.creds); req->work.creds = NULL; } if (req->work.fs) { struct fs_struct *fs = req->work.fs; if (req->flags & REQ_F_COMP_LOCKED) return true; spin_lock(&req->work.fs->lock); if (--fs->users) fs = NULL; spin_unlock(&req->work.fs->lock); if (fs) free_fs_struct(fs); req->work.fs = NULL; } return false; } static void io_prep_async_work(struct io_kiocb *req) { const struct io_op_def *def = &io_op_defs[req->opcode]; io_req_init_async(req); if (req->flags & REQ_F_ISREG) { if (def->hash_reg_file || (req->ctx->flags & IORING_SETUP_IOPOLL)) io_wq_hash_work(&req->work, file_inode(req->file)); } else { if (def->unbound_nonreg_file) req->work.flags |= IO_WQ_WORK_UNBOUND; } if (!req->work.mm && def->needs_mm) { mmgrab(current->mm); req->work.mm = current->mm; } if (!req->work.creds) req->work.creds = get_current_cred(); if (!req->work.fs && def->needs_fs) { spin_lock(¤t->fs->lock); if (!current->fs->in_exec) { req->work.fs = current->fs; req->work.fs->users++; } else { req->work.flags |= IO_WQ_WORK_CANCEL; } spin_unlock(¤t->fs->lock); } if (def->needs_fsize) req->work.fsize = rlimit(RLIMIT_FSIZE); else req->work.fsize = RLIM_INFINITY; } static void io_prep_async_link(struct io_kiocb *req) { struct io_kiocb *cur; io_prep_async_work(req); if (req->flags & REQ_F_LINK_HEAD) list_for_each_entry(cur, &req->link_list, link_list) io_prep_async_work(cur); } static struct io_kiocb *__io_queue_async_work(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; struct io_kiocb *link = io_prep_linked_timeout(req); trace_io_uring_queue_async_work(ctx, io_wq_is_hashed(&req->work), req, &req->work, req->flags); io_wq_enqueue(ctx->io_wq, &req->work); return link; } static void io_queue_async_work(struct io_kiocb *req) { struct io_kiocb *link; /* init ->work of the whole link before punting */ io_prep_async_link(req); link = __io_queue_async_work(req); if (link) io_queue_linked_timeout(link); } static void io_kill_timeout(struct io_kiocb *req) { int ret; ret = hrtimer_try_to_cancel(&req->io->timeout.timer); if (ret != -1) { atomic_set(&req->ctx->cq_timeouts, atomic_read(&req->ctx->cq_timeouts) + 1); list_del_init(&req->timeout.list); req->flags |= REQ_F_COMP_LOCKED; io_cqring_fill_event(req, 0); io_put_req(req); } } static void io_kill_timeouts(struct io_ring_ctx *ctx) { struct io_kiocb *req, *tmp; spin_lock_irq(&ctx->completion_lock); list_for_each_entry_safe(req, tmp, &ctx->timeout_list, timeout.list) io_kill_timeout(req); spin_unlock_irq(&ctx->completion_lock); } static void __io_queue_deferred(struct io_ring_ctx *ctx) { do { struct io_defer_entry *de = list_first_entry(&ctx->defer_list, struct io_defer_entry, list); struct io_kiocb *link; if (req_need_defer(de->req, de->seq)) break; list_del_init(&de->list); /* punt-init is done before queueing for defer */ link = __io_queue_async_work(de->req); if (link) { __io_queue_linked_timeout(link); /* drop submission reference */ link->flags |= REQ_F_COMP_LOCKED; io_put_req(link); } kfree(de); } while (!list_empty(&ctx->defer_list)); } static void io_flush_timeouts(struct io_ring_ctx *ctx) { while (!list_empty(&ctx->timeout_list)) { struct io_kiocb *req = list_first_entry(&ctx->timeout_list, struct io_kiocb, timeout.list); if (io_is_timeout_noseq(req)) break; if (req->timeout.target_seq != ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts)) break; list_del_init(&req->timeout.list); io_kill_timeout(req); } } static void io_commit_cqring(struct io_ring_ctx *ctx) { io_flush_timeouts(ctx); __io_commit_cqring(ctx); if (unlikely(!list_empty(&ctx->defer_list))) __io_queue_deferred(ctx); } static struct io_uring_cqe *io_get_cqring(struct io_ring_ctx *ctx) { struct io_rings *rings = ctx->rings; unsigned tail; tail = ctx->cached_cq_tail; /* * writes to the cq entry need to come after reading head; the * control dependency is enough as we're using WRITE_ONCE to * fill the cq entry */ if (tail - READ_ONCE(rings->cq.head) == rings->cq_ring_entries) return NULL; ctx->cached_cq_tail++; return &rings->cqes[tail & ctx->cq_mask]; } static inline bool io_should_trigger_evfd(struct io_ring_ctx *ctx) { if (!ctx->cq_ev_fd) return false; if (READ_ONCE(ctx->rings->cq_flags) & IORING_CQ_EVENTFD_DISABLED) return false; if (!ctx->eventfd_async) return true; return io_wq_current_is_worker(); } static void io_cqring_ev_posted(struct io_ring_ctx *ctx) { if (waitqueue_active(&ctx->wait)) wake_up(&ctx->wait); if (waitqueue_active(&ctx->sqo_wait)) wake_up(&ctx->sqo_wait); if (io_should_trigger_evfd(ctx)) eventfd_signal(ctx->cq_ev_fd, 1); } static void io_cqring_mark_overflow(struct io_ring_ctx *ctx) { if (list_empty(&ctx->cq_overflow_list)) { clear_bit(0, &ctx->sq_check_overflow); clear_bit(0, &ctx->cq_check_overflow); ctx->rings->sq_flags &= ~IORING_SQ_CQ_OVERFLOW; } } /* Returns true if there are no backlogged entries after the flush */ static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force) { struct io_rings *rings = ctx->rings; struct io_uring_cqe *cqe; struct io_kiocb *req; unsigned long flags; LIST_HEAD(list); if (!force) { if (list_empty_careful(&ctx->cq_overflow_list)) return true; if ((ctx->cached_cq_tail - READ_ONCE(rings->cq.head) == rings->cq_ring_entries)) return false; } spin_lock_irqsave(&ctx->completion_lock, flags); /* if force is set, the ring is going away. always drop after that */ if (force) ctx->cq_overflow_flushed = 1; cqe = NULL; while (!list_empty(&ctx->cq_overflow_list)) { cqe = io_get_cqring(ctx); if (!cqe && !force) break; req = list_first_entry(&ctx->cq_overflow_list, struct io_kiocb, compl.list); list_move(&req->compl.list, &list); if (cqe) { WRITE_ONCE(cqe->user_data, req->user_data); WRITE_ONCE(cqe->res, req->result); WRITE_ONCE(cqe->flags, req->compl.cflags); } else { WRITE_ONCE(ctx->rings->cq_overflow, atomic_inc_return(&ctx->cached_cq_overflow)); } } io_commit_cqring(ctx); io_cqring_mark_overflow(ctx); spin_unlock_irqrestore(&ctx->completion_lock, flags); io_cqring_ev_posted(ctx); while (!list_empty(&list)) { req = list_first_entry(&list, struct io_kiocb, compl.list); list_del(&req->compl.list); io_put_req(req); } return cqe != NULL; } static void __io_cqring_fill_event(struct io_kiocb *req, long res, long cflags) { struct io_ring_ctx *ctx = req->ctx; struct io_uring_cqe *cqe; trace_io_uring_complete(ctx, req->user_data, res); /* * If we can't get a cq entry, userspace overflowed the * submission (by quite a lot). Increment the overflow count in * the ring. */ cqe = io_get_cqring(ctx); if (likely(cqe)) { WRITE_ONCE(cqe->user_data, req->user_data); WRITE_ONCE(cqe->res, res); WRITE_ONCE(cqe->flags, cflags); } else if (ctx->cq_overflow_flushed) { WRITE_ONCE(ctx->rings->cq_overflow, atomic_inc_return(&ctx->cached_cq_overflow)); } else { if (list_empty(&ctx->cq_overflow_list)) { set_bit(0, &ctx->sq_check_overflow); set_bit(0, &ctx->cq_check_overflow); ctx->rings->sq_flags |= IORING_SQ_CQ_OVERFLOW; } io_clean_op(req); req->result = res; req->compl.cflags = cflags; refcount_inc(&req->refs); list_add_tail(&req->compl.list, &ctx->cq_overflow_list); } } static void io_cqring_fill_event(struct io_kiocb *req, long res) { __io_cqring_fill_event(req, res, 0); } static void io_cqring_add_event(struct io_kiocb *req, long res, long cflags) { struct io_ring_ctx *ctx = req->ctx; unsigned long flags; spin_lock_irqsave(&ctx->completion_lock, flags); __io_cqring_fill_event(req, res, cflags); io_commit_cqring(ctx); spin_unlock_irqrestore(&ctx->completion_lock, flags); io_cqring_ev_posted(ctx); } static void io_submit_flush_completions(struct io_comp_state *cs) { struct io_ring_ctx *ctx = cs->ctx; spin_lock_irq(&ctx->completion_lock); while (!list_empty(&cs->list)) { struct io_kiocb *req; req = list_first_entry(&cs->list, struct io_kiocb, compl.list); list_del(&req->compl.list); __io_cqring_fill_event(req, req->result, req->compl.cflags); if (!(req->flags & REQ_F_LINK_HEAD)) { req->flags |= REQ_F_COMP_LOCKED; io_put_req(req); } else { spin_unlock_irq(&ctx->completion_lock); io_put_req(req); spin_lock_irq(&ctx->completion_lock); } } io_commit_cqring(ctx); spin_unlock_irq(&ctx->completion_lock); io_cqring_ev_posted(ctx); cs->nr = 0; } static void __io_req_complete(struct io_kiocb *req, long res, unsigned cflags, struct io_comp_state *cs) { if (!cs) { io_cqring_add_event(req, res, cflags); io_put_req(req); } else { io_clean_op(req); req->result = res; req->compl.cflags = cflags; list_add_tail(&req->compl.list, &cs->list); if (++cs->nr >= 32) io_submit_flush_completions(cs); } } static void io_req_complete(struct io_kiocb *req, long res) { __io_req_complete(req, res, 0, NULL); } static inline bool io_is_fallback_req(struct io_kiocb *req) { return req == (struct io_kiocb *) ((unsigned long) req->ctx->fallback_req & ~1UL); } static struct io_kiocb *io_get_fallback_req(struct io_ring_ctx *ctx) { struct io_kiocb *req; req = ctx->fallback_req; if (!test_and_set_bit_lock(0, (unsigned long *) &ctx->fallback_req)) return req; return NULL; } static struct io_kiocb *io_alloc_req(struct io_ring_ctx *ctx, struct io_submit_state *state) { gfp_t gfp = GFP_KERNEL | __GFP_NOWARN; struct io_kiocb *req; if (!state->free_reqs) { size_t sz; int ret; sz = min_t(size_t, state->ios_left, ARRAY_SIZE(state->reqs)); ret = kmem_cache_alloc_bulk(req_cachep, gfp, sz, state->reqs); /* * Bulk alloc is all-or-nothing. If we fail to get a batch, * retry single alloc to be on the safe side. */ if (unlikely(ret <= 0)) { state->reqs[0] = kmem_cache_alloc(req_cachep, gfp); if (!state->reqs[0]) goto fallback; ret = 1; } state->free_reqs = ret - 1; req = state->reqs[ret - 1]; } else { state->free_reqs--; req = state->reqs[state->free_reqs]; } return req; fallback: return io_get_fallback_req(ctx); } static inline void io_put_file(struct io_kiocb *req, struct file *file, bool fixed) { if (fixed) percpu_ref_put(req->fixed_file_refs); else fput(file); } static bool io_dismantle_req(struct io_kiocb *req) { io_clean_op(req); if (req->io) kfree(req->io); if (req->file) io_put_file(req, req->file, (req->flags & REQ_F_FIXED_FILE)); return io_req_clean_work(req); } static void __io_free_req_finish(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; __io_put_req_task(req); if (likely(!io_is_fallback_req(req))) kmem_cache_free(req_cachep, req); else clear_bit_unlock(0, (unsigned long *) &ctx->fallback_req); percpu_ref_put(&ctx->refs); } static void io_req_task_file_table_put(struct callback_head *cb) { struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work); struct fs_struct *fs = req->work.fs; spin_lock(&req->work.fs->lock); if (--fs->users) fs = NULL; spin_unlock(&req->work.fs->lock); if (fs) free_fs_struct(fs); req->work.fs = NULL; __io_free_req_finish(req); } static void __io_free_req(struct io_kiocb *req) { if (!io_dismantle_req(req)) { __io_free_req_finish(req); } else { int ret; init_task_work(&req->task_work, io_req_task_file_table_put); ret = task_work_add(req->task, &req->task_work, TWA_RESUME); if (unlikely(ret)) { struct task_struct *tsk; tsk = io_wq_get_task(req->ctx->io_wq); task_work_add(tsk, &req->task_work, 0); } } } static bool io_link_cancel_timeout(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; int ret; ret = hrtimer_try_to_cancel(&req->io->timeout.timer); if (ret != -1) { io_cqring_fill_event(req, -ECANCELED); io_commit_cqring(ctx); req->flags &= ~REQ_F_LINK_HEAD; io_put_req(req); return true; } return false; } static bool __io_kill_linked_timeout(struct io_kiocb *req) { struct io_kiocb *link; bool wake_ev; if (list_empty(&req->link_list)) return false; link = list_first_entry(&req->link_list, struct io_kiocb, link_list); if (link->opcode != IORING_OP_LINK_TIMEOUT) return false; list_del_init(&link->link_list); link->flags |= REQ_F_COMP_LOCKED; wake_ev = io_link_cancel_timeout(link); req->flags &= ~REQ_F_LINK_TIMEOUT; return wake_ev; } static void io_kill_linked_timeout(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; bool wake_ev; if (!(req->flags & REQ_F_COMP_LOCKED)) { unsigned long flags; spin_lock_irqsave(&ctx->completion_lock, flags); wake_ev = __io_kill_linked_timeout(req); spin_unlock_irqrestore(&ctx->completion_lock, flags); } else { wake_ev = __io_kill_linked_timeout(req); } if (wake_ev) io_cqring_ev_posted(ctx); } static struct io_kiocb *io_req_link_next(struct io_kiocb *req) { struct io_kiocb *nxt; /* * The list should never be empty when we are called here. But could * potentially happen if the chain is messed up, check to be on the * safe side. */ if (unlikely(list_empty(&req->link_list))) return NULL; nxt = list_first_entry(&req->link_list, struct io_kiocb, link_list); list_del_init(&req->link_list); if (!list_empty(&nxt->link_list)) nxt->flags |= REQ_F_LINK_HEAD; return nxt; } /* * Called if REQ_F_LINK_HEAD is set, and we fail the head request */ static void __io_fail_links(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; while (!list_empty(&req->link_list)) { struct io_kiocb *link = list_first_entry(&req->link_list, struct io_kiocb, link_list); list_del_init(&link->link_list); trace_io_uring_fail_link(req, link); io_cqring_fill_event(link, -ECANCELED); link->flags |= REQ_F_COMP_LOCKED; __io_double_put_req(link); req->flags &= ~REQ_F_LINK_TIMEOUT; } io_commit_cqring(ctx); io_cqring_ev_posted(ctx); } static void io_fail_links(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; if (!(req->flags & REQ_F_COMP_LOCKED)) { unsigned long flags; spin_lock_irqsave(&ctx->completion_lock, flags); __io_fail_links(req); spin_unlock_irqrestore(&ctx->completion_lock, flags); } else { __io_fail_links(req); } io_cqring_ev_posted(ctx); } static struct io_kiocb *__io_req_find_next(struct io_kiocb *req) { req->flags &= ~REQ_F_LINK_HEAD; if (req->flags & REQ_F_LINK_TIMEOUT) io_kill_linked_timeout(req); /* * If LINK is set, we have dependent requests in this chain. If we * didn't fail this request, queue the first one up, moving any other * dependencies to the next request. In case of failure, fail the rest * of the chain. */ if (likely(!(req->flags & REQ_F_FAIL_LINK))) return io_req_link_next(req); io_fail_links(req); return NULL; } static struct io_kiocb *io_req_find_next(struct io_kiocb *req) { if (likely(!(req->flags & REQ_F_LINK_HEAD))) return NULL; return __io_req_find_next(req); } static int io_req_task_work_add(struct io_kiocb *req, struct callback_head *cb, bool twa_signal_ok) { struct task_struct *tsk = req->task; struct io_ring_ctx *ctx = req->ctx; int ret, notify; if (tsk->flags & PF_EXITING) return -ESRCH; /* * SQPOLL kernel thread doesn't need notification, just a wakeup. For * all other cases, use TWA_SIGNAL unconditionally to ensure we're * processing task_work. There's no reliable way to tell if TWA_RESUME * will do the job. */ notify = 0; if (!(ctx->flags & IORING_SETUP_SQPOLL) && twa_signal_ok) notify = TWA_SIGNAL; ret = task_work_add(tsk, cb, notify); if (!ret) wake_up_process(tsk); return ret; } static void __io_req_task_cancel(struct io_kiocb *req, int error) { struct io_ring_ctx *ctx = req->ctx; spin_lock_irq(&ctx->completion_lock); io_cqring_fill_event(req, error); io_commit_cqring(ctx); spin_unlock_irq(&ctx->completion_lock); io_cqring_ev_posted(ctx); req_set_fail_links(req); io_double_put_req(req); } static void io_req_task_cancel(struct callback_head *cb) { struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work); struct io_ring_ctx *ctx = req->ctx; __io_req_task_cancel(req, -ECANCELED); percpu_ref_put(&ctx->refs); } static void __io_req_task_submit(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; if (!__io_sq_thread_acquire_mm(ctx)) { mutex_lock(&ctx->uring_lock); __io_queue_sqe(req, NULL, NULL); mutex_unlock(&ctx->uring_lock); } else { __io_req_task_cancel(req, -EFAULT); } } static void io_req_task_submit(struct callback_head *cb) { struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work); struct io_ring_ctx *ctx = req->ctx; __io_req_task_submit(req); percpu_ref_put(&ctx->refs); } static void io_req_task_queue(struct io_kiocb *req) { int ret; init_task_work(&req->task_work, io_req_task_submit); percpu_ref_get(&req->ctx->refs); ret = io_req_task_work_add(req, &req->task_work, true); if (unlikely(ret)) { struct task_struct *tsk; init_task_work(&req->task_work, io_req_task_cancel); tsk = io_wq_get_task(req->ctx->io_wq); task_work_add(tsk, &req->task_work, 0); wake_up_process(tsk); } } static void io_queue_next(struct io_kiocb *req) { struct io_kiocb *nxt = io_req_find_next(req); if (nxt) io_req_task_queue(nxt); } static void io_free_req(struct io_kiocb *req) { io_queue_next(req); __io_free_req(req); } struct req_batch { void *reqs[IO_IOPOLL_BATCH]; int to_free; struct task_struct *task; int task_refs; }; static inline void io_init_req_batch(struct req_batch *rb) { rb->to_free = 0; rb->task_refs = 0; rb->task = NULL; } static void __io_req_free_batch_flush(struct io_ring_ctx *ctx, struct req_batch *rb) { kmem_cache_free_bulk(req_cachep, rb->to_free, rb->reqs); percpu_ref_put_many(&ctx->refs, rb->to_free); rb->to_free = 0; } static void io_req_free_batch_finish(struct io_ring_ctx *ctx, struct req_batch *rb) { if (rb->to_free) __io_req_free_batch_flush(ctx, rb); if (rb->task) { put_task_struct_many(rb->task, rb->task_refs); rb->task = NULL; } } static void io_req_free_batch(struct req_batch *rb, struct io_kiocb *req) { if (unlikely(io_is_fallback_req(req))) { io_free_req(req); return; } if (req->flags & REQ_F_LINK_HEAD) io_queue_next(req); if (req->flags & REQ_F_TASK_PINNED) { if (req->task != rb->task) { if (rb->task) put_task_struct_many(rb->task, rb->task_refs); rb->task = req->task; rb->task_refs = 0; } rb->task_refs++; req->flags &= ~REQ_F_TASK_PINNED; } WARN_ON_ONCE(io_dismantle_req(req)); rb->reqs[rb->to_free++] = req; if (unlikely(rb->to_free == ARRAY_SIZE(rb->reqs))) __io_req_free_batch_flush(req->ctx, rb); } /* * Drop reference to request, return next in chain (if there is one) if this * was the last reference to this request. */ static struct io_kiocb *io_put_req_find_next(struct io_kiocb *req) { struct io_kiocb *nxt = NULL; if (refcount_dec_and_test(&req->refs)) { nxt = io_req_find_next(req); __io_free_req(req); } return nxt; } static void io_put_req(struct io_kiocb *req) { if (refcount_dec_and_test(&req->refs)) io_free_req(req); } static struct io_wq_work *io_steal_work(struct io_kiocb *req) { struct io_kiocb *nxt; /* * A ref is owned by io-wq in which context we're. So, if that's the * last one, it's safe to steal next work. False negatives are Ok, * it just will be re-punted async in io_put_work() */ if (refcount_read(&req->refs) != 1) return NULL; nxt = io_req_find_next(req); return nxt ? &nxt->work : NULL; } /* * Must only be used if we don't need to care about links, usually from * within the completion handling itself. */ static void __io_double_put_req(struct io_kiocb *req) { /* drop both submit and complete references */ if (refcount_sub_and_test(2, &req->refs)) __io_free_req(req); } static void io_double_put_req(struct io_kiocb *req) { /* drop both submit and complete references */ if (refcount_sub_and_test(2, &req->refs)) io_free_req(req); } static unsigned io_cqring_events(struct io_ring_ctx *ctx, bool noflush) { struct io_rings *rings = ctx->rings; if (test_bit(0, &ctx->cq_check_overflow)) { /* * noflush == true is from the waitqueue handler, just ensure * we wake up the task, and the next invocation will flush the * entries. We cannot safely to it from here. */ if (noflush && !list_empty(&ctx->cq_overflow_list)) return -1U; io_cqring_overflow_flush(ctx, false); } /* See comment at the top of this file */ smp_rmb(); return ctx->cached_cq_tail - READ_ONCE(rings->cq.head); } static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx) { struct io_rings *rings = ctx->rings; /* make sure SQ entry isn't read before tail */ return smp_load_acquire(&rings->sq.tail) - ctx->cached_sq_head; } static unsigned int io_put_kbuf(struct io_kiocb *req, struct io_buffer *kbuf) { unsigned int cflags; cflags = kbuf->bid << IORING_CQE_BUFFER_SHIFT; cflags |= IORING_CQE_F_BUFFER; req->flags &= ~REQ_F_BUFFER_SELECTED; kfree(kbuf); return cflags; } static inline unsigned int io_put_rw_kbuf(struct io_kiocb *req) { struct io_buffer *kbuf; kbuf = (struct io_buffer *) (unsigned long) req->rw.addr; return io_put_kbuf(req, kbuf); } static inline bool io_run_task_work(void) { /* * Not safe to run on exiting task, and the task_work handling will * not add work to such a task. */ if (unlikely(current->flags & PF_EXITING)) return false; if (current->task_works) { __set_current_state(TASK_RUNNING); task_work_run(); return true; } return false; } static void io_iopoll_queue(struct list_head *again) { struct io_kiocb *req; do { req = list_first_entry(again, struct io_kiocb, inflight_entry); list_del(&req->inflight_entry); __io_complete_rw(req, -EAGAIN, 0, NULL); } while (!list_empty(again)); } /* * Find and free completed poll iocbs */ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events, struct list_head *done) { struct req_batch rb; struct io_kiocb *req; LIST_HEAD(again); /* order with ->result store in io_complete_rw_iopoll() */ smp_rmb(); io_init_req_batch(&rb); while (!list_empty(done)) { int cflags = 0; req = list_first_entry(done, struct io_kiocb, inflight_entry); if (READ_ONCE(req->result) == -EAGAIN) { req->result = 0; req->iopoll_completed = 0; list_move_tail(&req->inflight_entry, &again); continue; } list_del(&req->inflight_entry); if (req->flags & REQ_F_BUFFER_SELECTED) cflags = io_put_rw_kbuf(req); __io_cqring_fill_event(req, req->result, cflags); (*nr_events)++; if (refcount_dec_and_test(&req->refs)) io_req_free_batch(&rb, req); } io_commit_cqring(ctx); if (ctx->flags & IORING_SETUP_SQPOLL) io_cqring_ev_posted(ctx); io_req_free_batch_finish(ctx, &rb); if (!list_empty(&again)) io_iopoll_queue(&again); } static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events, long min) { struct io_kiocb *req, *tmp; LIST_HEAD(done); bool spin; int ret; /* * Only spin for completions if we don't have multiple devices hanging * off our complete list, and we're under the requested amount. */ spin = !ctx->poll_multi_file && *nr_events < min; ret = 0; list_for_each_entry_safe(req, tmp, &ctx->iopoll_list, inflight_entry) { struct kiocb *kiocb = &req->rw.kiocb; /* * Move completed and retryable entries to our local lists. * If we find a request that requires polling, break out * and complete those lists first, if we have entries there. */ if (READ_ONCE(req->iopoll_completed)) { list_move_tail(&req->inflight_entry, &done); continue; } if (!list_empty(&done)) break; ret = kiocb->ki_filp->f_op->iopoll(kiocb, spin); if (ret < 0) break; /* iopoll may have completed current req */ if (READ_ONCE(req->iopoll_completed)) list_move_tail(&req->inflight_entry, &done); if (ret && spin) spin = false; ret = 0; } if (!list_empty(&done)) io_iopoll_complete(ctx, nr_events, &done); return ret; } /* * Poll for a minimum of 'min' events. Note that if min == 0 we consider that a * non-spinning poll check - we'll still enter the driver poll loop, but only * as a non-spinning completion check. */ static int io_iopoll_getevents(struct io_ring_ctx *ctx, unsigned int *nr_events, long min) { while (!list_empty(&ctx->iopoll_list) && !need_resched()) { int ret; ret = io_do_iopoll(ctx, nr_events, min); if (ret < 0) return ret; if (*nr_events >= min) return 0; } return 1; } /* * We can't just wait for polled events to come to us, we have to actively * find and complete them. */ static void io_iopoll_try_reap_events(struct io_ring_ctx *ctx) { if (!(ctx->flags & IORING_SETUP_IOPOLL)) return; mutex_lock(&ctx->uring_lock); while (!list_empty(&ctx->iopoll_list)) { unsigned int nr_events = 0; io_do_iopoll(ctx, &nr_events, 0); /* let it sleep and repeat later if can't complete a request */ if (nr_events == 0) break; /* * Ensure we allow local-to-the-cpu processing to take place, * in this case we need to ensure that we reap all events. * Also let task_work, etc. to progress by releasing the mutex */ if (need_resched()) { mutex_unlock(&ctx->uring_lock); cond_resched(); mutex_lock(&ctx->uring_lock); } } mutex_unlock(&ctx->uring_lock); } static int io_iopoll_check(struct io_ring_ctx *ctx, long min) { unsigned int nr_events = 0; int iters = 0, ret = 0; /* * We disallow the app entering submit/complete with polling, but we * still need to lock the ring to prevent racing with polled issue * that got punted to a workqueue. */ mutex_lock(&ctx->uring_lock); do { /* * Don't enter poll loop if we already have events pending. * If we do, we can potentially be spinning for commands that * already triggered a CQE (eg in error). */ if (io_cqring_events(ctx, false)) break; /* * If a submit got punted to a workqueue, we can have the * application entering polling for a command before it gets * issued. That app will hold the uring_lock for the duration * of the poll right here, so we need to take a breather every * now and then to ensure that the issue has a chance to add * the poll to the issued list. Otherwise we can spin here * forever, while the workqueue is stuck trying to acquire the * very same mutex. */ if (!(++iters & 7)) { mutex_unlock(&ctx->uring_lock); io_run_task_work(); mutex_lock(&ctx->uring_lock); } ret = io_iopoll_getevents(ctx, &nr_events, min); if (ret <= 0) break; ret = 0; } while (min && !nr_events && !need_resched()); mutex_unlock(&ctx->uring_lock); return ret; } static void kiocb_end_write(struct io_kiocb *req) { /* * Tell lockdep we inherited freeze protection from submission * thread. */ if (req->flags & REQ_F_ISREG) { struct inode *inode = file_inode(req->file); __sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE); } file_end_write(req->file); } static void io_complete_rw_common(struct kiocb *kiocb, long res, struct io_comp_state *cs) { struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb); int cflags = 0; if (kiocb->ki_flags & IOCB_WRITE) kiocb_end_write(req); if (res != req->result) req_set_fail_links(req); if (req->flags & REQ_F_BUFFER_SELECTED) cflags = io_put_rw_kbuf(req); __io_req_complete(req, res, cflags, cs); } #ifdef CONFIG_BLOCK static bool io_resubmit_prep(struct io_kiocb *req, int error) { struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; ssize_t ret = -ECANCELED; struct iov_iter iter; int rw; if (error) { ret = error; goto end_req; } switch (req->opcode) { case IORING_OP_READV: case IORING_OP_READ_FIXED: case IORING_OP_READ: rw = READ; break; case IORING_OP_WRITEV: case IORING_OP_WRITE_FIXED: case IORING_OP_WRITE: rw = WRITE; break; default: printk_once(KERN_WARNING "io_uring: bad opcode in resubmit %d\n", req->opcode); goto end_req; } if (!req->io) { ret = io_import_iovec(rw, req, &iovec, &iter, false); if (ret < 0) goto end_req; ret = io_setup_async_rw(req, iovec, inline_vecs, &iter, false); if (!ret) return true; kfree(iovec); } else { return true; } end_req: req_set_fail_links(req); io_req_complete(req, ret); return false; } #endif static bool io_rw_reissue(struct io_kiocb *req, long res) { #ifdef CONFIG_BLOCK umode_t mode = file_inode(req->file)->i_mode; int ret; if (!S_ISBLK(mode) && !S_ISREG(mode)) return false; if ((res != -EAGAIN && res != -EOPNOTSUPP) || io_wq_current_is_worker()) return false; ret = io_sq_thread_acquire_mm(req->ctx, req); if (io_resubmit_prep(req, ret)) { refcount_inc(&req->refs); io_queue_async_work(req); return true; } #endif return false; } static void __io_complete_rw(struct io_kiocb *req, long res, long res2, struct io_comp_state *cs) { if (!io_rw_reissue(req, res)) io_complete_rw_common(&req->rw.kiocb, res, cs); } static void io_complete_rw(struct kiocb *kiocb, long res, long res2) { struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb); __io_complete_rw(req, res, res2, NULL); } static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2) { struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb); if (kiocb->ki_flags & IOCB_WRITE) kiocb_end_write(req); if (res != -EAGAIN && res != req->result) req_set_fail_links(req); WRITE_ONCE(req->result, res); /* order with io_poll_complete() checking ->result */ smp_wmb(); WRITE_ONCE(req->iopoll_completed, 1); } /* * After the iocb has been issued, it's safe to be found on the poll list. * Adding the kiocb to the list AFTER submission ensures that we don't * find it from a io_iopoll_getevents() thread before the issuer is done * accessing the kiocb cookie. */ static void io_iopoll_req_issued(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; /* * Track whether we have multiple files in our lists. This will impact * how we do polling eventually, not spinning if we're on potentially * different devices. */ if (list_empty(&ctx->iopoll_list)) { ctx->poll_multi_file = false; } else if (!ctx->poll_multi_file) { struct io_kiocb *list_req; list_req = list_first_entry(&ctx->iopoll_list, struct io_kiocb, inflight_entry); if (list_req->file != req->file) ctx->poll_multi_file = true; } /* * For fast devices, IO may have already completed. If it has, add * it to the front so we find it first. */ if (READ_ONCE(req->iopoll_completed)) list_add(&req->inflight_entry, &ctx->iopoll_list); else list_add_tail(&req->inflight_entry, &ctx->iopoll_list); if ((ctx->flags & IORING_SETUP_SQPOLL) && wq_has_sleeper(&ctx->sqo_wait)) wake_up(&ctx->sqo_wait); } static void __io_state_file_put(struct io_submit_state *state) { if (state->has_refs) fput_many(state->file, state->has_refs); state->file = NULL; } static inline void io_state_file_put(struct io_submit_state *state) { if (state->file) __io_state_file_put(state); } /* * Get as many references to a file as we have IOs left in this submission, * assuming most submissions are for one file, or at least that each file * has more than one submission. */ static struct file *__io_file_get(struct io_submit_state *state, int fd) { if (!state) return fget(fd); if (state->file) { if (state->fd == fd) { state->has_refs--; state->ios_left--; return state->file; } __io_state_file_put(state); } state->file = fget_many(fd, state->ios_left); if (!state->file) return NULL; state->fd = fd; state->ios_left--; state->has_refs = state->ios_left; return state->file; } static bool io_bdev_nowait(struct block_device *bdev) { #ifdef CONFIG_BLOCK return !bdev || queue_is_mq(bdev_get_queue(bdev)); #else return true; #endif } /* * If we tracked the file through the SCM inflight mechanism, we could support * any file. For now, just ensure that anything potentially problematic is done * inline. */ static bool io_file_supports_async(struct file *file, int rw) { umode_t mode = file_inode(file)->i_mode; if (S_ISBLK(mode)) { if (io_bdev_nowait(file->f_inode->i_bdev)) return true; return false; } if (S_ISCHR(mode) || S_ISSOCK(mode)) return true; if (S_ISREG(mode)) { if (io_bdev_nowait(file->f_inode->i_sb->s_bdev) && file->f_op != &io_uring_fops) return true; return false; } /* any ->read/write should understand O_NONBLOCK */ if (file->f_flags & O_NONBLOCK) return true; if (!(file->f_mode & FMODE_NOWAIT)) return false; if (rw == READ) return file->f_op->read_iter != NULL; return file->f_op->write_iter != NULL; } static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe, bool force_nonblock) { struct io_ring_ctx *ctx = req->ctx; struct kiocb *kiocb = &req->rw.kiocb; unsigned ioprio; int ret; if (S_ISREG(file_inode(req->file)->i_mode)) req->flags |= REQ_F_ISREG; kiocb->ki_pos = READ_ONCE(sqe->off); if (kiocb->ki_pos == -1 && !(req->file->f_mode & FMODE_STREAM)) { req->flags |= REQ_F_CUR_POS; kiocb->ki_pos = req->file->f_pos; } kiocb->ki_hint = ki_hint_validate(file_write_hint(kiocb->ki_filp)); kiocb->ki_flags = iocb_flags(kiocb->ki_filp); ret = kiocb_set_rw_flags(kiocb, READ_ONCE(sqe->rw_flags)); if (unlikely(ret)) return ret; ioprio = READ_ONCE(sqe->ioprio); if (ioprio) { ret = ioprio_check_cap(ioprio); if (ret) return ret; kiocb->ki_ioprio = ioprio; } else kiocb->ki_ioprio = get_current_ioprio(); /* don't allow async punt if RWF_NOWAIT was requested */ if (kiocb->ki_flags & IOCB_NOWAIT) req->flags |= REQ_F_NOWAIT; if (kiocb->ki_flags & IOCB_DIRECT) io_get_req_task(req); if (force_nonblock) kiocb->ki_flags |= IOCB_NOWAIT; if (ctx->flags & IORING_SETUP_IOPOLL) { if (!(kiocb->ki_flags & IOCB_DIRECT) || !kiocb->ki_filp->f_op->iopoll) return -EOPNOTSUPP; kiocb->ki_flags |= IOCB_HIPRI; kiocb->ki_complete = io_complete_rw_iopoll; req->iopoll_completed = 0; io_get_req_task(req); } else { if (kiocb->ki_flags & IOCB_HIPRI) return -EINVAL; kiocb->ki_complete = io_complete_rw; } req->rw.addr = READ_ONCE(sqe->addr); req->rw.len = READ_ONCE(sqe->len); req->buf_index = READ_ONCE(sqe->buf_index); return 0; } static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret) { switch (ret) { case -EIOCBQUEUED: break; case -ERESTARTSYS: case -ERESTARTNOINTR: case -ERESTARTNOHAND: case -ERESTART_RESTARTBLOCK: /* * We can't just restart the syscall, since previously * submitted sqes may already be in progress. Just fail this * IO with EINTR. */ ret = -EINTR; fallthrough; default: kiocb->ki_complete(kiocb, ret, 0); } } static void kiocb_done(struct kiocb *kiocb, ssize_t ret, struct io_comp_state *cs) { struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb); /* add previously done IO, if any */ if (req->io && req->io->rw.bytes_done > 0) { if (ret < 0) ret = req->io->rw.bytes_done; else ret += req->io->rw.bytes_done; } if (req->flags & REQ_F_CUR_POS) req->file->f_pos = kiocb->ki_pos; if (ret >= 0 && kiocb->ki_complete == io_complete_rw) __io_complete_rw(req, ret, 0, cs); else io_rw_done(kiocb, ret); } static ssize_t io_import_fixed(struct io_kiocb *req, int rw, struct iov_iter *iter) { struct io_ring_ctx *ctx = req->ctx; size_t len = req->rw.len; struct io_mapped_ubuf *imu; u16 index, buf_index; size_t offset; u64 buf_addr; /* attempt to use fixed buffers without having provided iovecs */ if (unlikely(!ctx->user_bufs)) return -EFAULT; buf_index = req->buf_index; if (unlikely(buf_index >= ctx->nr_user_bufs)) return -EFAULT; index = array_index_nospec(buf_index, ctx->nr_user_bufs); imu = &ctx->user_bufs[index]; buf_addr = req->rw.addr; /* overflow */ if (buf_addr + len < buf_addr) return -EFAULT; /* not inside the mapped region */ if (buf_addr < imu->ubuf || buf_addr + len > imu->ubuf + imu->len) return -EFAULT; /* * May not be a start of buffer, set size appropriately * and advance us to the beginning. */ offset = buf_addr - imu->ubuf; iov_iter_bvec(iter, rw, imu->bvec, imu->nr_bvecs, offset + len); if (offset) { /* * Don't use iov_iter_advance() here, as it's really slow for * using the latter parts of a big fixed buffer - it iterates * over each segment manually. We can cheat a bit here, because * we know that: * * 1) it's a BVEC iter, we set it up * 2) all bvecs are PAGE_SIZE in size, except potentially the * first and last bvec * * So just find our index, and adjust the iterator afterwards. * If the offset is within the first bvec (or the whole first * bvec, just use iov_iter_advance(). This makes it easier * since we can just skip the first segment, which may not * be PAGE_SIZE aligned. */ const struct bio_vec *bvec = imu->bvec; if (offset <= bvec->bv_len) { iov_iter_advance(iter, offset); } else { unsigned long seg_skip; /* skip first vec */ offset -= bvec->bv_len; seg_skip = 1 + (offset >> PAGE_SHIFT); iter->bvec = bvec + seg_skip; iter->nr_segs -= seg_skip; iter->count -= bvec->bv_len + offset; iter->iov_offset = offset & ~PAGE_MASK; } } return len; } static void io_ring_submit_unlock(struct io_ring_ctx *ctx, bool needs_lock) { if (needs_lock) mutex_unlock(&ctx->uring_lock); } static void io_ring_submit_lock(struct io_ring_ctx *ctx, bool needs_lock) { /* * "Normal" inline submissions always hold the uring_lock, since we * grab it from the system call. Same is true for the SQPOLL offload. * The only exception is when we've detached the request and issue it * from an async worker thread, grab the lock for that case. */ if (needs_lock) mutex_lock(&ctx->uring_lock); } static struct io_buffer *io_buffer_select(struct io_kiocb *req, size_t *len, int bgid, struct io_buffer *kbuf, bool needs_lock) { struct io_buffer *head; if (req->flags & REQ_F_BUFFER_SELECTED) return kbuf; io_ring_submit_lock(req->ctx, needs_lock); lockdep_assert_held(&req->ctx->uring_lock); head = idr_find(&req->ctx->io_buffer_idr, bgid); if (head) { if (!list_empty(&head->list)) { kbuf = list_last_entry(&head->list, struct io_buffer, list); list_del(&kbuf->list); } else { kbuf = head; idr_remove(&req->ctx->io_buffer_idr, bgid); } if (*len > kbuf->len) *len = kbuf->len; } else { kbuf = ERR_PTR(-ENOBUFS); } io_ring_submit_unlock(req->ctx, needs_lock); return kbuf; } static void __user *io_rw_buffer_select(struct io_kiocb *req, size_t *len, bool needs_lock) { struct io_buffer *kbuf; u16 bgid; kbuf = (struct io_buffer *) (unsigned long) req->rw.addr; bgid = req->buf_index; kbuf = io_buffer_select(req, len, bgid, kbuf, needs_lock); if (IS_ERR(kbuf)) return kbuf; req->rw.addr = (u64) (unsigned long) kbuf; req->flags |= REQ_F_BUFFER_SELECTED; return u64_to_user_ptr(kbuf->addr); } #ifdef CONFIG_COMPAT static ssize_t io_compat_import(struct io_kiocb *req, struct iovec *iov, bool needs_lock) { struct compat_iovec __user *uiov; compat_ssize_t clen; void __user *buf; ssize_t len; uiov = u64_to_user_ptr(req->rw.addr); if (!access_ok(uiov, sizeof(*uiov))) return -EFAULT; if (__get_user(clen, &uiov->iov_len)) return -EFAULT; if (clen < 0) return -EINVAL; len = clen; buf = io_rw_buffer_select(req, &len, needs_lock); if (IS_ERR(buf)) return PTR_ERR(buf); iov[0].iov_base = buf; iov[0].iov_len = (compat_size_t) len; return 0; } #endif static ssize_t __io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov, bool needs_lock) { struct iovec __user *uiov = u64_to_user_ptr(req->rw.addr); void __user *buf; ssize_t len; if (copy_from_user(iov, uiov, sizeof(*uiov))) return -EFAULT; len = iov[0].iov_len; if (len < 0) return -EINVAL; buf = io_rw_buffer_select(req, &len, needs_lock); if (IS_ERR(buf)) return PTR_ERR(buf); iov[0].iov_base = buf; iov[0].iov_len = len; return 0; } static ssize_t io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov, bool needs_lock) { if (req->flags & REQ_F_BUFFER_SELECTED) { struct io_buffer *kbuf; kbuf = (struct io_buffer *) (unsigned long) req->rw.addr; iov[0].iov_base = u64_to_user_ptr(kbuf->addr); iov[0].iov_len = kbuf->len; return 0; } if (!req->rw.len) return 0; else if (req->rw.len > 1) return -EINVAL; #ifdef CONFIG_COMPAT if (req->ctx->compat) return io_compat_import(req, iov, needs_lock); #endif return __io_iov_buffer_select(req, iov, needs_lock); } static ssize_t __io_import_iovec(int rw, struct io_kiocb *req, struct iovec **iovec, struct iov_iter *iter, bool needs_lock) { void __user *buf = u64_to_user_ptr(req->rw.addr); size_t sqe_len = req->rw.len; ssize_t ret; u8 opcode; opcode = req->opcode; if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) { *iovec = NULL; return io_import_fixed(req, rw, iter); } /* buffer index only valid with fixed read/write, or buffer select */ if (req->buf_index && !(req->flags & REQ_F_BUFFER_SELECT)) return -EINVAL; if (opcode == IORING_OP_READ || opcode == IORING_OP_WRITE) { if (req->flags & REQ_F_BUFFER_SELECT) { buf = io_rw_buffer_select(req, &sqe_len, needs_lock); if (IS_ERR(buf)) return PTR_ERR(buf); req->rw.len = sqe_len; } ret = import_single_range(rw, buf, sqe_len, *iovec, iter); *iovec = NULL; return ret < 0 ? ret : sqe_len; } if (req->flags & REQ_F_BUFFER_SELECT) { ret = io_iov_buffer_select(req, *iovec, needs_lock); if (!ret) { ret = (*iovec)->iov_len; iov_iter_init(iter, rw, *iovec, 1, ret); } *iovec = NULL; return ret; } #ifdef CONFIG_COMPAT if (req->ctx->compat) return compat_import_iovec(rw, buf, sqe_len, UIO_FASTIOV, iovec, iter); #endif return import_iovec(rw, buf, sqe_len, UIO_FASTIOV, iovec, iter); } static ssize_t io_import_iovec(int rw, struct io_kiocb *req, struct iovec **iovec, struct iov_iter *iter, bool needs_lock) { if (!req->io) return __io_import_iovec(rw, req, iovec, iter, needs_lock); *iovec = NULL; return iov_iter_count(&req->io->rw.iter); } static inline loff_t *io_kiocb_ppos(struct kiocb *kiocb) { return kiocb->ki_filp->f_mode & FMODE_STREAM ? NULL : &kiocb->ki_pos; } /* * For files that don't have ->read_iter() and ->write_iter(), handle them * by looping over ->read() or ->write() manually. */ static ssize_t loop_rw_iter(int rw, struct file *file, struct kiocb *kiocb, struct iov_iter *iter) { ssize_t ret = 0; /* * Don't support polled IO through this interface, and we can't * support non-blocking either. For the latter, this just causes * the kiocb to be handled from an async context. */ if (kiocb->ki_flags & IOCB_HIPRI) return -EOPNOTSUPP; if (kiocb->ki_flags & IOCB_NOWAIT) return -EAGAIN; while (iov_iter_count(iter)) { struct iovec iovec; ssize_t nr; if (!iov_iter_is_bvec(iter)) { iovec = iov_iter_iovec(iter); } else { /* fixed buffers import bvec */ iovec.iov_base = kmap(iter->bvec->bv_page) + iter->iov_offset; iovec.iov_len = min(iter->count, iter->bvec->bv_len - iter->iov_offset); } if (rw == READ) { nr = file->f_op->read(file, iovec.iov_base, iovec.iov_len, io_kiocb_ppos(kiocb)); } else { nr = file->f_op->write(file, iovec.iov_base, iovec.iov_len, io_kiocb_ppos(kiocb)); } if (iov_iter_is_bvec(iter)) kunmap(iter->bvec->bv_page); if (nr < 0) { if (!ret) ret = nr; break; } ret += nr; if (nr != iovec.iov_len) break; iov_iter_advance(iter, nr); } return ret; } static void io_req_map_rw(struct io_kiocb *req, const struct iovec *iovec, const struct iovec *fast_iov, struct iov_iter *iter) { struct io_async_rw *rw = &req->io->rw; memcpy(&rw->iter, iter, sizeof(*iter)); rw->free_iovec = NULL; rw->bytes_done = 0; /* can only be fixed buffers, no need to do anything */ if (iter->type == ITER_BVEC) return; if (!iovec) { unsigned iov_off = 0; rw->iter.iov = rw->fast_iov; if (iter->iov != fast_iov) { iov_off = iter->iov - fast_iov; rw->iter.iov += iov_off; } if (rw->fast_iov != fast_iov) memcpy(rw->fast_iov + iov_off, fast_iov + iov_off, sizeof(struct iovec) * iter->nr_segs); } else { rw->free_iovec = iovec; req->flags |= REQ_F_NEED_CLEANUP; } } static inline int __io_alloc_async_ctx(struct io_kiocb *req) { req->io = kmalloc(sizeof(*req->io), GFP_KERNEL); return req->io == NULL; } static int io_alloc_async_ctx(struct io_kiocb *req) { if (!io_op_defs[req->opcode].async_ctx) return 0; return __io_alloc_async_ctx(req); } static int io_setup_async_rw(struct io_kiocb *req, const struct iovec *iovec, const struct iovec *fast_iov, struct iov_iter *iter, bool force) { if (!force && !io_op_defs[req->opcode].async_ctx) return 0; if (!req->io) { if (__io_alloc_async_ctx(req)) return -ENOMEM; io_req_map_rw(req, iovec, fast_iov, iter); } return 0; } static inline int io_rw_prep_async(struct io_kiocb *req, int rw, bool force_nonblock) { struct io_async_rw *iorw = &req->io->rw; struct iovec *iov; ssize_t ret; iorw->iter.iov = iov = iorw->fast_iov; ret = __io_import_iovec(rw, req, &iov, &iorw->iter, !force_nonblock); if (unlikely(ret < 0)) return ret; iorw->iter.iov = iov; io_req_map_rw(req, iorw->iter.iov, iorw->fast_iov, &iorw->iter); return 0; } static int io_read_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe, bool force_nonblock) { ssize_t ret; ret = io_prep_rw(req, sqe, force_nonblock); if (ret) return ret; if (unlikely(!(req->file->f_mode & FMODE_READ))) return -EBADF; /* either don't need iovec imported or already have it */ if (!req->io || req->flags & REQ_F_NEED_CLEANUP) return 0; return io_rw_prep_async(req, READ, force_nonblock); } /* * This is our waitqueue callback handler, registered through lock_page_async() * when we initially tried to do the IO with the iocb armed our waitqueue. * This gets called when the page is unlocked, and we generally expect that to * happen when the page IO is completed and the page is now uptodate. This will * queue a task_work based retry of the operation, attempting to copy the data * again. If the latter fails because the page was NOT uptodate, then we will * do a thread based blocking retry of the operation. That's the unexpected * slow path. */ static int io_async_buf_func(struct wait_queue_entry *wait, unsigned mode, int sync, void *arg) { struct wait_page_queue *wpq; struct io_kiocb *req = wait->private; struct wait_page_key *key = arg; int ret; wpq = container_of(wait, struct wait_page_queue, wait); if (!wake_page_match(wpq, key)) return 0; req->rw.kiocb.ki_flags &= ~IOCB_WAITQ; list_del_init(&wait->entry); init_task_work(&req->task_work, io_req_task_submit); percpu_ref_get(&req->ctx->refs); /* submit ref gets dropped, acquire a new one */ refcount_inc(&req->refs); ret = io_req_task_work_add(req, &req->task_work, true); if (unlikely(ret)) { struct task_struct *tsk; /* queue just for cancelation */ init_task_work(&req->task_work, io_req_task_cancel); tsk = io_wq_get_task(req->ctx->io_wq); task_work_add(tsk, &req->task_work, 0); wake_up_process(tsk); } return 1; } /* * This controls whether a given IO request should be armed for async page * based retry. If we return false here, the request is handed to the async * worker threads for retry. If we're doing buffered reads on a regular file, * we prepare a private wait_page_queue entry and retry the operation. This * will either succeed because the page is now uptodate and unlocked, or it * will register a callback when the page is unlocked at IO completion. Through * that callback, io_uring uses task_work to setup a retry of the operation. * That retry will attempt the buffered read again. The retry will generally * succeed, or in rare cases where it fails, we then fall back to using the * async worker threads for a blocking retry. */ static bool io_rw_should_retry(struct io_kiocb *req) { struct wait_page_queue *wait = &req->io->rw.wpq; struct kiocb *kiocb = &req->rw.kiocb; /* never retry for NOWAIT, we just complete with -EAGAIN */ if (req->flags & REQ_F_NOWAIT) return false; /* Only for buffered IO */ if (kiocb->ki_flags & (IOCB_DIRECT | IOCB_HIPRI)) return false; /* * just use poll if we can, and don't attempt if the fs doesn't * support callback based unlocks */ if (file_can_poll(req->file) || !(req->file->f_mode & FMODE_BUF_RASYNC)) return false; wait->wait.func = io_async_buf_func; wait->wait.private = req; wait->wait.flags = 0; INIT_LIST_HEAD(&wait->wait.entry); kiocb->ki_flags |= IOCB_WAITQ; kiocb->ki_flags &= ~IOCB_NOWAIT; kiocb->ki_waitq = wait; io_get_req_task(req); return true; } static int io_iter_do_read(struct io_kiocb *req, struct iov_iter *iter) { if (req->file->f_op->read_iter) return call_read_iter(req->file, &req->rw.kiocb, iter); else if (req->file->f_op->read) return loop_rw_iter(READ, req->file, &req->rw.kiocb, iter); else return -EINVAL; } static int io_read(struct io_kiocb *req, bool force_nonblock, struct io_comp_state *cs) { struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; struct kiocb *kiocb = &req->rw.kiocb; struct iov_iter __iter, *iter = &__iter; ssize_t io_size, ret, ret2; size_t iov_count; bool no_async; if (req->io) iter = &req->io->rw.iter; ret = io_import_iovec(READ, req, &iovec, iter, !force_nonblock); if (ret < 0) return ret; iov_count = iov_iter_count(iter); io_size = ret; req->result = io_size; ret = 0; /* Ensure we clear previously set non-block flag */ if (!force_nonblock) kiocb->ki_flags &= ~IOCB_NOWAIT; /* If the file doesn't support async, just async punt */ no_async = force_nonblock && !io_file_supports_async(req->file, READ); if (no_async) goto copy_iov; ret = rw_verify_area(READ, req->file, io_kiocb_ppos(kiocb), iov_count); if (unlikely(ret)) goto out_free; ret = io_iter_do_read(req, iter); if (!ret) { goto done; } else if (ret == -EIOCBQUEUED) { ret = 0; goto out_free; } else if (ret == -EAGAIN) { /* IOPOLL retry should happen for io-wq threads */ if (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL)) goto done; /* no retry on NONBLOCK marked file */ if (req->file->f_flags & O_NONBLOCK) goto done; /* some cases will consume bytes even on error returns */ iov_iter_revert(iter, iov_count - iov_iter_count(iter)); ret = 0; goto copy_iov; } else if (ret < 0) { /* make sure -ERESTARTSYS -> -EINTR is done */ goto done; } /* read it all, or we did blocking attempt. no retry. */ if (!iov_iter_count(iter) || !force_nonblock || (req->file->f_flags & O_NONBLOCK)) goto done; io_size -= ret; copy_iov: ret2 = io_setup_async_rw(req, iovec, inline_vecs, iter, true); if (ret2) { ret = ret2; goto out_free; } if (no_async) return -EAGAIN; /* it's copied and will be cleaned with ->io */ iovec = NULL; /* now use our persistent iterator, if we aren't already */ iter = &req->io->rw.iter; retry: req->io->rw.bytes_done += ret; /* if we can retry, do so with the callbacks armed */ if (!io_rw_should_retry(req)) { kiocb->ki_flags &= ~IOCB_WAITQ; return -EAGAIN; } /* * Now retry read with the IOCB_WAITQ parts set in the iocb. If we * get -EIOCBQUEUED, then we'll get a notification when the desired * page gets unlocked. We can also get a partial read here, and if we * do, then just retry at the new offset. */ ret = io_iter_do_read(req, iter); if (ret == -EIOCBQUEUED) { ret = 0; goto out_free; } else if (ret > 0 && ret < io_size) { /* we got some bytes, but not all. retry. */ goto retry; } done: kiocb_done(kiocb, ret, cs); ret = 0; out_free: /* it's reportedly faster than delegating the null check to kfree() */ if (iovec) kfree(iovec); return ret; } static int io_write_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe, bool force_nonblock) { ssize_t ret; ret = io_prep_rw(req, sqe, force_nonblock); if (ret) return ret; if (unlikely(!(req->file->f_mode & FMODE_WRITE))) return -EBADF; /* either don't need iovec imported or already have it */ if (!req->io || req->flags & REQ_F_NEED_CLEANUP) return 0; return io_rw_prep_async(req, WRITE, force_nonblock); } static int io_write(struct io_kiocb *req, bool force_nonblock, struct io_comp_state *cs) { struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; struct kiocb *kiocb = &req->rw.kiocb; struct iov_iter __iter, *iter = &__iter; size_t iov_count; ssize_t ret, ret2, io_size; if (req->io) iter = &req->io->rw.iter; ret = io_import_iovec(WRITE, req, &iovec, iter, !force_nonblock); if (ret < 0) return ret; iov_count = iov_iter_count(iter); io_size = ret; req->result = io_size; /* Ensure we clear previously set non-block flag */ if (!force_nonblock) req->rw.kiocb.ki_flags &= ~IOCB_NOWAIT; /* If the file doesn't support async, just async punt */ if (force_nonblock && !io_file_supports_async(req->file, WRITE)) goto copy_iov; /* file path doesn't support NOWAIT for non-direct_IO */ if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT) && (req->flags & REQ_F_ISREG)) goto copy_iov; ret = rw_verify_area(WRITE, req->file, io_kiocb_ppos(kiocb), iov_count); if (unlikely(ret)) goto out_free; /* * Open-code file_start_write here to grab freeze protection, * which will be released by another thread in * io_complete_rw(). Fool lockdep by telling it the lock got * released so that it doesn't complain about the held lock when * we return to userspace. */ if (req->flags & REQ_F_ISREG) { __sb_start_write(file_inode(req->file)->i_sb, SB_FREEZE_WRITE, true); __sb_writers_release(file_inode(req->file)->i_sb, SB_FREEZE_WRITE); } kiocb->ki_flags |= IOCB_WRITE; if (req->file->f_op->write_iter) ret2 = call_write_iter(req->file, kiocb, iter); else if (req->file->f_op->write) ret2 = loop_rw_iter(WRITE, req->file, kiocb, iter); else ret2 = -EINVAL; /* * Raw bdev writes will return -EOPNOTSUPP for IOCB_NOWAIT. Just * retry them without IOCB_NOWAIT. */ if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT)) ret2 = -EAGAIN; /* no retry on NONBLOCK marked file */ if (ret2 == -EAGAIN && (req->file->f_flags & O_NONBLOCK)) goto done; if (!force_nonblock || ret2 != -EAGAIN) { /* IOPOLL retry should happen for io-wq threads */ if ((req->ctx->flags & IORING_SETUP_IOPOLL) && ret2 == -EAGAIN) goto copy_iov; done: kiocb_done(kiocb, ret2, cs); } else { copy_iov: /* some cases will consume bytes even on error returns */ iov_iter_revert(iter, iov_count - iov_iter_count(iter)); ret = io_setup_async_rw(req, iovec, inline_vecs, iter, false); if (!ret) return -EAGAIN; } out_free: /* it's reportedly faster than delegating the null check to kfree() */ if (iovec) kfree(iovec); return ret; } static int __io_splice_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_splice* sp = &req->splice; unsigned int valid_flags = SPLICE_F_FD_IN_FIXED | SPLICE_F_ALL; int ret; if (req->flags & REQ_F_NEED_CLEANUP) return 0; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; sp->file_in = NULL; sp->len = READ_ONCE(sqe->len); sp->flags = READ_ONCE(sqe->splice_flags); if (unlikely(sp->flags & ~valid_flags)) return -EINVAL; ret = io_file_get(NULL, req, READ_ONCE(sqe->splice_fd_in), &sp->file_in, (sp->flags & SPLICE_F_FD_IN_FIXED)); if (ret) return ret; req->flags |= REQ_F_NEED_CLEANUP; if (!S_ISREG(file_inode(sp->file_in)->i_mode)) { /* * Splice operation will be punted aync, and here need to * modify io_wq_work.flags, so initialize io_wq_work firstly. */ io_req_init_async(req); req->work.flags |= IO_WQ_WORK_UNBOUND; } return 0; } static int io_tee_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (READ_ONCE(sqe->splice_off_in) || READ_ONCE(sqe->off)) return -EINVAL; return __io_splice_prep(req, sqe); } static int io_tee(struct io_kiocb *req, bool force_nonblock) { struct io_splice *sp = &req->splice; struct file *in = sp->file_in; struct file *out = sp->file_out; unsigned int flags = sp->flags & ~SPLICE_F_FD_IN_FIXED; long ret = 0; if (force_nonblock) return -EAGAIN; if (sp->len) ret = do_tee(in, out, sp->len, flags); io_put_file(req, in, (sp->flags & SPLICE_F_FD_IN_FIXED)); req->flags &= ~REQ_F_NEED_CLEANUP; if (ret != sp->len) req_set_fail_links(req); io_req_complete(req, ret); return 0; } static int io_splice_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_splice* sp = &req->splice; sp->off_in = READ_ONCE(sqe->splice_off_in); sp->off_out = READ_ONCE(sqe->off); return __io_splice_prep(req, sqe); } static int io_splice(struct io_kiocb *req, bool force_nonblock) { struct io_splice *sp = &req->splice; struct file *in = sp->file_in; struct file *out = sp->file_out; unsigned int flags = sp->flags & ~SPLICE_F_FD_IN_FIXED; loff_t *poff_in, *poff_out; long ret = 0; if (force_nonblock) return -EAGAIN; poff_in = (sp->off_in == -1) ? NULL : &sp->off_in; poff_out = (sp->off_out == -1) ? NULL : &sp->off_out; if (sp->len) ret = do_splice(in, poff_in, out, poff_out, sp->len, flags); io_put_file(req, in, (sp->flags & SPLICE_F_FD_IN_FIXED)); req->flags &= ~REQ_F_NEED_CLEANUP; if (ret != sp->len) req_set_fail_links(req); io_req_complete(req, ret); return 0; } /* * IORING_OP_NOP just posts a completion event, nothing else. */ static int io_nop(struct io_kiocb *req, struct io_comp_state *cs) { struct io_ring_ctx *ctx = req->ctx; if (unlikely(ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; __io_req_complete(req, 0, 0, cs); return 0; } static int io_prep_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_ring_ctx *ctx = req->ctx; if (!req->file) return -EBADF; if (unlikely(ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index)) return -EINVAL; req->sync.flags = READ_ONCE(sqe->fsync_flags); if (unlikely(req->sync.flags & ~IORING_FSYNC_DATASYNC)) return -EINVAL; req->sync.off = READ_ONCE(sqe->off); req->sync.len = READ_ONCE(sqe->len); return 0; } static int io_fsync(struct io_kiocb *req, bool force_nonblock) { loff_t end = req->sync.off + req->sync.len; int ret; /* fsync always requires a blocking context */ if (force_nonblock) return -EAGAIN; ret = vfs_fsync_range(req->file, req->sync.off, end > 0 ? end : LLONG_MAX, req->sync.flags & IORING_FSYNC_DATASYNC); if (ret < 0) req_set_fail_links(req); io_req_complete(req, ret); return 0; } static int io_fallocate_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (sqe->ioprio || sqe->buf_index || sqe->rw_flags) return -EINVAL; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; req->sync.off = READ_ONCE(sqe->off); req->sync.len = READ_ONCE(sqe->addr); req->sync.mode = READ_ONCE(sqe->len); return 0; } static int io_fallocate(struct io_kiocb *req, bool force_nonblock) { int ret; /* fallocate always requiring blocking context */ if (force_nonblock) return -EAGAIN; ret = vfs_fallocate(req->file, req->sync.mode, req->sync.off, req->sync.len); if (ret < 0) req_set_fail_links(req); io_req_complete(req, ret); return 0; } static int __io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { const char __user *fname; int ret; if (unlikely(sqe->ioprio || sqe->buf_index)) return -EINVAL; if (unlikely(req->flags & REQ_F_FIXED_FILE)) return -EBADF; /* open.how should be already initialised */ if (!(req->open.how.flags & O_PATH) && force_o_largefile()) req->open.how.flags |= O_LARGEFILE; req->open.dfd = READ_ONCE(sqe->fd); fname = u64_to_user_ptr(READ_ONCE(sqe->addr)); req->open.filename = getname(fname); if (IS_ERR(req->open.filename)) { ret = PTR_ERR(req->open.filename); req->open.filename = NULL; return ret; } req->open.nofile = rlimit(RLIMIT_NOFILE); req->flags |= REQ_F_NEED_CLEANUP; return 0; } static int io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { u64 flags, mode; if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL))) return -EINVAL; if (req->flags & REQ_F_NEED_CLEANUP) return 0; mode = READ_ONCE(sqe->len); flags = READ_ONCE(sqe->open_flags); req->open.how = build_open_how(flags, mode); return __io_openat_prep(req, sqe); } static int io_openat2_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct open_how __user *how; size_t len; int ret; if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL))) return -EINVAL; if (req->flags & REQ_F_NEED_CLEANUP) return 0; how = u64_to_user_ptr(READ_ONCE(sqe->addr2)); len = READ_ONCE(sqe->len); if (len < OPEN_HOW_SIZE_VER0) return -EINVAL; ret = copy_struct_from_user(&req->open.how, sizeof(req->open.how), how, len); if (ret) return ret; return __io_openat_prep(req, sqe); } static int io_openat2(struct io_kiocb *req, bool force_nonblock) { struct open_flags op; struct file *file; int ret; if (force_nonblock) return -EAGAIN; ret = build_open_flags(&req->open.how, &op); if (ret) goto err; ret = __get_unused_fd_flags(req->open.how.flags, req->open.nofile); if (ret < 0) goto err; file = do_filp_open(req->open.dfd, req->open.filename, &op); if (IS_ERR(file)) { put_unused_fd(ret); ret = PTR_ERR(file); } else { fsnotify_open(file); fd_install(ret, file); } err: putname(req->open.filename); req->flags &= ~REQ_F_NEED_CLEANUP; if (ret < 0) req_set_fail_links(req); io_req_complete(req, ret); return 0; } static int io_openat(struct io_kiocb *req, bool force_nonblock) { return io_openat2(req, force_nonblock); } static int io_remove_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_provide_buf *p = &req->pbuf; u64 tmp; if (sqe->ioprio || sqe->rw_flags || sqe->addr || sqe->len || sqe->off) return -EINVAL; tmp = READ_ONCE(sqe->fd); if (!tmp || tmp > USHRT_MAX) return -EINVAL; memset(p, 0, sizeof(*p)); p->nbufs = tmp; p->bgid = READ_ONCE(sqe->buf_group); return 0; } static int __io_remove_buffers(struct io_ring_ctx *ctx, struct io_buffer *buf, int bgid, unsigned nbufs) { unsigned i = 0; /* shouldn't happen */ if (!nbufs) return 0; /* the head kbuf is the list itself */ while (!list_empty(&buf->list)) { struct io_buffer *nxt; nxt = list_first_entry(&buf->list, struct io_buffer, list); list_del(&nxt->list); kfree(nxt); if (++i == nbufs) return i; } i++; kfree(buf); idr_remove(&ctx->io_buffer_idr, bgid); return i; } static int io_remove_buffers(struct io_kiocb *req, bool force_nonblock, struct io_comp_state *cs) { struct io_provide_buf *p = &req->pbuf; struct io_ring_ctx *ctx = req->ctx; struct io_buffer *head; int ret = 0; io_ring_submit_lock(ctx, !force_nonblock); lockdep_assert_held(&ctx->uring_lock); ret = -ENOENT; head = idr_find(&ctx->io_buffer_idr, p->bgid); if (head) ret = __io_remove_buffers(ctx, head, p->bgid, p->nbufs); io_ring_submit_lock(ctx, !force_nonblock); if (ret < 0) req_set_fail_links(req); __io_req_complete(req, ret, 0, cs); return 0; } static int io_provide_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_provide_buf *p = &req->pbuf; u64 tmp; if (sqe->ioprio || sqe->rw_flags) return -EINVAL; tmp = READ_ONCE(sqe->fd); if (!tmp || tmp > USHRT_MAX) return -E2BIG; p->nbufs = tmp; p->addr = READ_ONCE(sqe->addr); p->len = READ_ONCE(sqe->len); if (!access_ok(u64_to_user_ptr(p->addr), (p->len * p->nbufs))) return -EFAULT; p->bgid = READ_ONCE(sqe->buf_group); tmp = READ_ONCE(sqe->off); if (tmp > USHRT_MAX) return -E2BIG; p->bid = tmp; return 0; } static int io_add_buffers(struct io_provide_buf *pbuf, struct io_buffer **head) { struct io_buffer *buf; u64 addr = pbuf->addr; int i, bid = pbuf->bid; for (i = 0; i < pbuf->nbufs; i++) { buf = kmalloc(sizeof(*buf), GFP_KERNEL); if (!buf) break; buf->addr = addr; buf->len = pbuf->len; buf->bid = bid; addr += pbuf->len; bid++; if (!*head) { INIT_LIST_HEAD(&buf->list); *head = buf; } else { list_add_tail(&buf->list, &(*head)->list); } } return i ? i : -ENOMEM; } static int io_provide_buffers(struct io_kiocb *req, bool force_nonblock, struct io_comp_state *cs) { struct io_provide_buf *p = &req->pbuf; struct io_ring_ctx *ctx = req->ctx; struct io_buffer *head, *list; int ret = 0; io_ring_submit_lock(ctx, !force_nonblock); lockdep_assert_held(&ctx->uring_lock); list = head = idr_find(&ctx->io_buffer_idr, p->bgid); ret = io_add_buffers(p, &head); if (ret < 0) goto out; if (!list) { ret = idr_alloc(&ctx->io_buffer_idr, head, p->bgid, p->bgid + 1, GFP_KERNEL); if (ret < 0) { __io_remove_buffers(ctx, head, p->bgid, -1U); goto out; } } out: io_ring_submit_unlock(ctx, !force_nonblock); if (ret < 0) req_set_fail_links(req); __io_req_complete(req, ret, 0, cs); return 0; } static int io_epoll_ctl_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { #if defined(CONFIG_EPOLL) if (sqe->ioprio || sqe->buf_index) return -EINVAL; if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL))) return -EINVAL; req->epoll.epfd = READ_ONCE(sqe->fd); req->epoll.op = READ_ONCE(sqe->len); req->epoll.fd = READ_ONCE(sqe->off); if (ep_op_has_event(req->epoll.op)) { struct epoll_event __user *ev; ev = u64_to_user_ptr(READ_ONCE(sqe->addr)); if (copy_from_user(&req->epoll.event, ev, sizeof(*ev))) return -EFAULT; } return 0; #else return -EOPNOTSUPP; #endif } static int io_epoll_ctl(struct io_kiocb *req, bool force_nonblock, struct io_comp_state *cs) { #if defined(CONFIG_EPOLL) struct io_epoll *ie = &req->epoll; int ret; ret = do_epoll_ctl(ie->epfd, ie->op, ie->fd, &ie->event, force_nonblock); if (force_nonblock && ret == -EAGAIN) return -EAGAIN; if (ret < 0) req_set_fail_links(req); __io_req_complete(req, ret, 0, cs); return 0; #else return -EOPNOTSUPP; #endif } static int io_madvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { #if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU) if (sqe->ioprio || sqe->buf_index || sqe->off) return -EINVAL; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; req->madvise.addr = READ_ONCE(sqe->addr); req->madvise.len = READ_ONCE(sqe->len); req->madvise.advice = READ_ONCE(sqe->fadvise_advice); return 0; #else return -EOPNOTSUPP; #endif } static int io_madvise(struct io_kiocb *req, bool force_nonblock) { #if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU) struct io_madvise *ma = &req->madvise; int ret; if (force_nonblock) return -EAGAIN; ret = do_madvise(ma->addr, ma->len, ma->advice); if (ret < 0) req_set_fail_links(req); io_req_complete(req, ret); return 0; #else return -EOPNOTSUPP; #endif } static int io_fadvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (sqe->ioprio || sqe->buf_index || sqe->addr) return -EINVAL; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; req->fadvise.offset = READ_ONCE(sqe->off); req->fadvise.len = READ_ONCE(sqe->len); req->fadvise.advice = READ_ONCE(sqe->fadvise_advice); return 0; } static int io_fadvise(struct io_kiocb *req, bool force_nonblock) { struct io_fadvise *fa = &req->fadvise; int ret; if (force_nonblock) { switch (fa->advice) { case POSIX_FADV_NORMAL: case POSIX_FADV_RANDOM: case POSIX_FADV_SEQUENTIAL: break; default: return -EAGAIN; } } ret = vfs_fadvise(req->file, fa->offset, fa->len, fa->advice); if (ret < 0) req_set_fail_links(req); io_req_complete(req, ret); return 0; } static int io_statx_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL))) return -EINVAL; if (sqe->ioprio || sqe->buf_index) return -EINVAL; if (req->flags & REQ_F_FIXED_FILE) return -EBADF; req->statx.dfd = READ_ONCE(sqe->fd); req->statx.mask = READ_ONCE(sqe->len); req->statx.filename = u64_to_user_ptr(READ_ONCE(sqe->addr)); req->statx.buffer = u64_to_user_ptr(READ_ONCE(sqe->addr2)); req->statx.flags = READ_ONCE(sqe->statx_flags); return 0; } static int io_statx(struct io_kiocb *req, bool force_nonblock) { struct io_statx *ctx = &req->statx; int ret; if (force_nonblock) { /* only need file table for an actual valid fd */ if (ctx->dfd == -1 || ctx->dfd == AT_FDCWD) req->flags |= REQ_F_NO_FILE_TABLE; return -EAGAIN; } ret = do_statx(ctx->dfd, ctx->filename, ctx->flags, ctx->mask, ctx->buffer); if (ret < 0) req_set_fail_links(req); io_req_complete(req, ret); return 0; } static int io_close_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { /* * If we queue this for async, it must not be cancellable. That would * leave the 'file' in an undeterminate state, and here need to modify * io_wq_work.flags, so initialize io_wq_work firstly. */ io_req_init_async(req); req->work.flags |= IO_WQ_WORK_NO_CANCEL; if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL))) return -EINVAL; if (sqe->ioprio || sqe->off || sqe->addr || sqe->len || sqe->rw_flags || sqe->buf_index) return -EINVAL; if (req->flags & REQ_F_FIXED_FILE) return -EBADF; req->close.fd = READ_ONCE(sqe->fd); if ((req->file && req->file->f_op == &io_uring_fops) || req->close.fd == req->ctx->ring_fd) return -EBADF; req->close.put_file = NULL; return 0; } static int io_close(struct io_kiocb *req, bool force_nonblock, struct io_comp_state *cs) { struct io_close *close = &req->close; int ret; /* might be already done during nonblock submission */ if (!close->put_file) { ret = __close_fd_get_file(close->fd, &close->put_file); if (ret < 0) return (ret == -ENOENT) ? -EBADF : ret; } /* if the file has a flush method, be safe and punt to async */ if (close->put_file->f_op->flush && force_nonblock) { /* was never set, but play safe */ req->flags &= ~REQ_F_NOWAIT; /* avoid grabbing files - we don't need the files */ req->flags |= REQ_F_NO_FILE_TABLE; return -EAGAIN; } /* No ->flush() or already async, safely close from here */ ret = filp_close(close->put_file, req->work.files); if (ret < 0) req_set_fail_links(req); fput(close->put_file); close->put_file = NULL; __io_req_complete(req, ret, 0, cs); return 0; } static int io_prep_sfr(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_ring_ctx *ctx = req->ctx; if (!req->file) return -EBADF; if (unlikely(ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index)) return -EINVAL; req->sync.off = READ_ONCE(sqe->off); req->sync.len = READ_ONCE(sqe->len); req->sync.flags = READ_ONCE(sqe->sync_range_flags); return 0; } static int io_sync_file_range(struct io_kiocb *req, bool force_nonblock) { int ret; /* sync_file_range always requires a blocking context */ if (force_nonblock) return -EAGAIN; ret = sync_file_range(req->file, req->sync.off, req->sync.len, req->sync.flags); if (ret < 0) req_set_fail_links(req); io_req_complete(req, ret); return 0; } #if defined(CONFIG_NET) static int io_setup_async_msg(struct io_kiocb *req, struct io_async_msghdr *kmsg) { if (req->io) return -EAGAIN; if (io_alloc_async_ctx(req)) { if (kmsg->iov != kmsg->fast_iov) kfree(kmsg->iov); return -ENOMEM; } req->flags |= REQ_F_NEED_CLEANUP; memcpy(&req->io->msg, kmsg, sizeof(*kmsg)); return -EAGAIN; } static int io_sendmsg_copy_hdr(struct io_kiocb *req, struct io_async_msghdr *iomsg) { iomsg->iov = iomsg->fast_iov; iomsg->msg.msg_name = &iomsg->addr; return sendmsg_copy_msghdr(&iomsg->msg, req->sr_msg.umsg, req->sr_msg.msg_flags, &iomsg->iov); } static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_sr_msg *sr = &req->sr_msg; struct io_async_ctx *io = req->io; int ret; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; sr->msg_flags = READ_ONCE(sqe->msg_flags); sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr)); sr->len = READ_ONCE(sqe->len); #ifdef CONFIG_COMPAT if (req->ctx->compat) sr->msg_flags |= MSG_CMSG_COMPAT; #endif if (!io || req->opcode == IORING_OP_SEND) return 0; /* iovec is already imported */ if (req->flags & REQ_F_NEED_CLEANUP) return 0; ret = io_sendmsg_copy_hdr(req, &io->msg); if (!ret) req->flags |= REQ_F_NEED_CLEANUP; return ret; } static int io_sendmsg(struct io_kiocb *req, bool force_nonblock, struct io_comp_state *cs) { struct io_async_msghdr iomsg, *kmsg; struct socket *sock; unsigned flags; int ret; sock = sock_from_file(req->file, &ret); if (unlikely(!sock)) return ret; if (req->io) { kmsg = &req->io->msg; kmsg->msg.msg_name = &req->io->msg.addr; /* if iov is set, it's allocated already */ if (!kmsg->iov) kmsg->iov = kmsg->fast_iov; kmsg->msg.msg_iter.iov = kmsg->iov; } else { ret = io_sendmsg_copy_hdr(req, &iomsg); if (ret) return ret; kmsg = &iomsg; } flags = req->sr_msg.msg_flags; if (flags & MSG_DONTWAIT) req->flags |= REQ_F_NOWAIT; else if (force_nonblock) flags |= MSG_DONTWAIT; ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags); if (force_nonblock && ret == -EAGAIN) return io_setup_async_msg(req, kmsg); if (ret == -ERESTARTSYS) ret = -EINTR; if (kmsg->iov != kmsg->fast_iov) kfree(kmsg->iov); req->flags &= ~REQ_F_NEED_CLEANUP; if (ret < 0) req_set_fail_links(req); __io_req_complete(req, ret, 0, cs); return 0; } static int io_send(struct io_kiocb *req, bool force_nonblock, struct io_comp_state *cs) { struct io_sr_msg *sr = &req->sr_msg; struct msghdr msg; struct iovec iov; struct socket *sock; unsigned flags; int ret; sock = sock_from_file(req->file, &ret); if (unlikely(!sock)) return ret; ret = import_single_range(WRITE, sr->buf, sr->len, &iov, &msg.msg_iter); if (unlikely(ret)) return ret;; msg.msg_name = NULL; msg.msg_control = NULL; msg.msg_controllen = 0; msg.msg_namelen = 0; flags = req->sr_msg.msg_flags; if (flags & MSG_DONTWAIT) req->flags |= REQ_F_NOWAIT; else if (force_nonblock) flags |= MSG_DONTWAIT; msg.msg_flags = flags; ret = sock_sendmsg(sock, &msg); if (force_nonblock && ret == -EAGAIN) return -EAGAIN; if (ret == -ERESTARTSYS) ret = -EINTR; if (ret < 0) req_set_fail_links(req); __io_req_complete(req, ret, 0, cs); return 0; } static int __io_recvmsg_copy_hdr(struct io_kiocb *req, struct io_async_msghdr *iomsg) { struct io_sr_msg *sr = &req->sr_msg; struct iovec __user *uiov; size_t iov_len; int ret; ret = __copy_msghdr_from_user(&iomsg->msg, sr->umsg, &iomsg->uaddr, &uiov, &iov_len); if (ret) return ret; if (req->flags & REQ_F_BUFFER_SELECT) { if (iov_len > 1) return -EINVAL; if (copy_from_user(iomsg->iov, uiov, sizeof(*uiov))) return -EFAULT; sr->len = iomsg->iov[0].iov_len; iov_iter_init(&iomsg->msg.msg_iter, READ, iomsg->iov, 1, sr->len); iomsg->iov = NULL; } else { ret = import_iovec(READ, uiov, iov_len, UIO_FASTIOV, &iomsg->iov, &iomsg->msg.msg_iter); if (ret > 0) ret = 0; } return ret; } #ifdef CONFIG_COMPAT static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req, struct io_async_msghdr *iomsg) { struct compat_msghdr __user *msg_compat; struct io_sr_msg *sr = &req->sr_msg; struct compat_iovec __user *uiov; compat_uptr_t ptr; compat_size_t len; int ret; msg_compat = (struct compat_msghdr __user *) sr->umsg; ret = __get_compat_msghdr(&iomsg->msg, msg_compat, &iomsg->uaddr, &ptr, &len); if (ret) return ret; uiov = compat_ptr(ptr); if (req->flags & REQ_F_BUFFER_SELECT) { compat_ssize_t clen; if (len > 1) return -EINVAL; if (!access_ok(uiov, sizeof(*uiov))) return -EFAULT; if (__get_user(clen, &uiov->iov_len)) return -EFAULT; if (clen < 0) return -EINVAL; sr->len = iomsg->iov[0].iov_len; iomsg->iov = NULL; } else { ret = compat_import_iovec(READ, uiov, len, UIO_FASTIOV, &iomsg->iov, &iomsg->msg.msg_iter); if (ret < 0) return ret; } return 0; } #endif static int io_recvmsg_copy_hdr(struct io_kiocb *req, struct io_async_msghdr *iomsg) { iomsg->msg.msg_name = &iomsg->addr; iomsg->iov = iomsg->fast_iov; #ifdef CONFIG_COMPAT if (req->ctx->compat) return __io_compat_recvmsg_copy_hdr(req, iomsg); #endif return __io_recvmsg_copy_hdr(req, iomsg); } static struct io_buffer *io_recv_buffer_select(struct io_kiocb *req, bool needs_lock) { struct io_sr_msg *sr = &req->sr_msg; struct io_buffer *kbuf; kbuf = io_buffer_select(req, &sr->len, sr->bgid, sr->kbuf, needs_lock); if (IS_ERR(kbuf)) return kbuf; sr->kbuf = kbuf; req->flags |= REQ_F_BUFFER_SELECTED; return kbuf; } static inline unsigned int io_put_recv_kbuf(struct io_kiocb *req) { return io_put_kbuf(req, req->sr_msg.kbuf); } static int io_recvmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_sr_msg *sr = &req->sr_msg; struct io_async_ctx *io = req->io; int ret; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; sr->msg_flags = READ_ONCE(sqe->msg_flags); sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr)); sr->len = READ_ONCE(sqe->len); sr->bgid = READ_ONCE(sqe->buf_group); #ifdef CONFIG_COMPAT if (req->ctx->compat) sr->msg_flags |= MSG_CMSG_COMPAT; #endif if (!io || req->opcode == IORING_OP_RECV) return 0; /* iovec is already imported */ if (req->flags & REQ_F_NEED_CLEANUP) return 0; ret = io_recvmsg_copy_hdr(req, &io->msg); if (!ret) req->flags |= REQ_F_NEED_CLEANUP; return ret; } static int io_recvmsg(struct io_kiocb *req, bool force_nonblock, struct io_comp_state *cs) { struct io_async_msghdr iomsg, *kmsg; struct socket *sock; struct io_buffer *kbuf; unsigned flags; int ret, cflags = 0; sock = sock_from_file(req->file, &ret); if (unlikely(!sock)) return ret; if (req->io) { kmsg = &req->io->msg; kmsg->msg.msg_name = &req->io->msg.addr; /* if iov is set, it's allocated already */ if (!kmsg->iov) kmsg->iov = kmsg->fast_iov; kmsg->msg.msg_iter.iov = kmsg->iov; } else { ret = io_recvmsg_copy_hdr(req, &iomsg); if (ret) return ret; kmsg = &iomsg; } if (req->flags & REQ_F_BUFFER_SELECT) { kbuf = io_recv_buffer_select(req, !force_nonblock); if (IS_ERR(kbuf)) return PTR_ERR(kbuf); kmsg->fast_iov[0].iov_base = u64_to_user_ptr(kbuf->addr); iov_iter_init(&kmsg->msg.msg_iter, READ, kmsg->iov, 1, req->sr_msg.len); } flags = req->sr_msg.msg_flags; if (flags & MSG_DONTWAIT) req->flags |= REQ_F_NOWAIT; else if (force_nonblock) flags |= MSG_DONTWAIT; ret = __sys_recvmsg_sock(sock, &kmsg->msg, req->sr_msg.umsg, kmsg->uaddr, flags); if (force_nonblock && ret == -EAGAIN) return io_setup_async_msg(req, kmsg); if (ret == -ERESTARTSYS) ret = -EINTR; if (req->flags & REQ_F_BUFFER_SELECTED) cflags = io_put_recv_kbuf(req); if (kmsg->iov != kmsg->fast_iov) kfree(kmsg->iov); req->flags &= ~REQ_F_NEED_CLEANUP; if (ret < 0) req_set_fail_links(req); __io_req_complete(req, ret, cflags, cs); return 0; } static int io_recv(struct io_kiocb *req, bool force_nonblock, struct io_comp_state *cs) { struct io_buffer *kbuf; struct io_sr_msg *sr = &req->sr_msg; struct msghdr msg; void __user *buf = sr->buf; struct socket *sock; struct iovec iov; unsigned flags; int ret, cflags = 0; sock = sock_from_file(req->file, &ret); if (unlikely(!sock)) return ret; if (req->flags & REQ_F_BUFFER_SELECT) { kbuf = io_recv_buffer_select(req, !force_nonblock); if (IS_ERR(kbuf)) return PTR_ERR(kbuf); buf = u64_to_user_ptr(kbuf->addr); } ret = import_single_range(READ, buf, sr->len, &iov, &msg.msg_iter); if (unlikely(ret)) goto out_free; msg.msg_name = NULL; msg.msg_control = NULL; msg.msg_controllen = 0; msg.msg_namelen = 0; msg.msg_iocb = NULL; msg.msg_flags = 0; flags = req->sr_msg.msg_flags; if (flags & MSG_DONTWAIT) req->flags |= REQ_F_NOWAIT; else if (force_nonblock) flags |= MSG_DONTWAIT; ret = sock_recvmsg(sock, &msg, flags); if (force_nonblock && ret == -EAGAIN) return -EAGAIN; if (ret == -ERESTARTSYS) ret = -EINTR; out_free: if (req->flags & REQ_F_BUFFER_SELECTED) cflags = io_put_recv_kbuf(req); if (ret < 0) req_set_fail_links(req); __io_req_complete(req, ret, cflags, cs); return 0; } static int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_accept *accept = &req->accept; if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL))) return -EINVAL; if (sqe->ioprio || sqe->len || sqe->buf_index) return -EINVAL; accept->addr = u64_to_user_ptr(READ_ONCE(sqe->addr)); accept->addr_len = u64_to_user_ptr(READ_ONCE(sqe->addr2)); accept->flags = READ_ONCE(sqe->accept_flags); accept->nofile = rlimit(RLIMIT_NOFILE); return 0; } static int io_accept(struct io_kiocb *req, bool force_nonblock, struct io_comp_state *cs) { struct io_accept *accept = &req->accept; unsigned int file_flags = force_nonblock ? O_NONBLOCK : 0; int ret; if (req->file->f_flags & O_NONBLOCK) req->flags |= REQ_F_NOWAIT; ret = __sys_accept4_file(req->file, file_flags, accept->addr, accept->addr_len, accept->flags, accept->nofile); if (ret == -EAGAIN && force_nonblock) return -EAGAIN; if (ret < 0) { if (ret == -ERESTARTSYS) ret = -EINTR; req_set_fail_links(req); } __io_req_complete(req, ret, 0, cs); return 0; } static int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_connect *conn = &req->connect; struct io_async_ctx *io = req->io; if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL))) return -EINVAL; if (sqe->ioprio || sqe->len || sqe->buf_index || sqe->rw_flags) return -EINVAL; conn->addr = u64_to_user_ptr(READ_ONCE(sqe->addr)); conn->addr_len = READ_ONCE(sqe->addr2); if (!io) return 0; return move_addr_to_kernel(conn->addr, conn->addr_len, &io->connect.address); } static int io_connect(struct io_kiocb *req, bool force_nonblock, struct io_comp_state *cs) { struct io_async_ctx __io, *io; unsigned file_flags; int ret; if (req->io) { io = req->io; } else { ret = move_addr_to_kernel(req->connect.addr, req->connect.addr_len, &__io.connect.address); if (ret) goto out; io = &__io; } file_flags = force_nonblock ? O_NONBLOCK : 0; ret = __sys_connect_file(req->file, &io->connect.address, req->connect.addr_len, file_flags); if ((ret == -EAGAIN || ret == -EINPROGRESS) && force_nonblock) { if (req->io) return -EAGAIN; if (io_alloc_async_ctx(req)) { ret = -ENOMEM; goto out; } memcpy(&req->io->connect, &__io.connect, sizeof(__io.connect)); return -EAGAIN; } if (ret == -ERESTARTSYS) ret = -EINTR; out: if (ret < 0) req_set_fail_links(req); __io_req_complete(req, ret, 0, cs); return 0; } #else /* !CONFIG_NET */ static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { return -EOPNOTSUPP; } static int io_sendmsg(struct io_kiocb *req, bool force_nonblock, struct io_comp_state *cs) { return -EOPNOTSUPP; } static int io_send(struct io_kiocb *req, bool force_nonblock, struct io_comp_state *cs) { return -EOPNOTSUPP; } static int io_recvmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { return -EOPNOTSUPP; } static int io_recvmsg(struct io_kiocb *req, bool force_nonblock, struct io_comp_state *cs) { return -EOPNOTSUPP; } static int io_recv(struct io_kiocb *req, bool force_nonblock, struct io_comp_state *cs) { return -EOPNOTSUPP; } static int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { return -EOPNOTSUPP; } static int io_accept(struct io_kiocb *req, bool force_nonblock, struct io_comp_state *cs) { return -EOPNOTSUPP; } static int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { return -EOPNOTSUPP; } static int io_connect(struct io_kiocb *req, bool force_nonblock, struct io_comp_state *cs) { return -EOPNOTSUPP; } #endif /* CONFIG_NET */ struct io_poll_table { struct poll_table_struct pt; struct io_kiocb *req; int error; }; static int __io_async_wake(struct io_kiocb *req, struct io_poll_iocb *poll, __poll_t mask, task_work_func_t func) { bool twa_signal_ok; int ret; /* for instances that support it check for an event match first: */ if (mask && !(mask & poll->events)) return 0; trace_io_uring_task_add(req->ctx, req->opcode, req->user_data, mask); list_del_init(&poll->wait.entry); req->result = mask; init_task_work(&req->task_work, func); percpu_ref_get(&req->ctx->refs); /* * If we using the signalfd wait_queue_head for this wakeup, then * it's not safe to use TWA_SIGNAL as we could be recursing on the * tsk->sighand->siglock on doing the wakeup. Should not be needed * either, as the normal wakeup will suffice. */ twa_signal_ok = (poll->head != &req->task->sighand->signalfd_wqh); /* * If this fails, then the task is exiting. When a task exits, the * work gets canceled, so just cancel this request as well instead * of executing it. We can't safely execute it anyway, as we may not * have the needed state needed for it anyway. */ ret = io_req_task_work_add(req, &req->task_work, twa_signal_ok); if (unlikely(ret)) { struct task_struct *tsk; WRITE_ONCE(poll->canceled, true); tsk = io_wq_get_task(req->ctx->io_wq); task_work_add(tsk, &req->task_work, 0); wake_up_process(tsk); } return 1; } static bool io_poll_rewait(struct io_kiocb *req, struct io_poll_iocb *poll) __acquires(&req->ctx->completion_lock) { struct io_ring_ctx *ctx = req->ctx; if (!req->result && !READ_ONCE(poll->canceled)) { struct poll_table_struct pt = { ._key = poll->events }; req->result = vfs_poll(req->file, &pt) & poll->events; } spin_lock_irq(&ctx->completion_lock); if (!req->result && !READ_ONCE(poll->canceled)) { add_wait_queue(poll->head, &poll->wait); return true; } return false; } static struct io_poll_iocb *io_poll_get_double(struct io_kiocb *req) { /* pure poll stashes this in ->io, poll driven retry elsewhere */ if (req->opcode == IORING_OP_POLL_ADD) return (struct io_poll_iocb *) req->io; return req->apoll->double_poll; } static struct io_poll_iocb *io_poll_get_single(struct io_kiocb *req) { if (req->opcode == IORING_OP_POLL_ADD) return &req->poll; return &req->apoll->poll; } static void io_poll_remove_double(struct io_kiocb *req) { struct io_poll_iocb *poll = io_poll_get_double(req); lockdep_assert_held(&req->ctx->completion_lock); if (poll && poll->head) { struct wait_queue_head *head = poll->head; spin_lock(&head->lock); list_del_init(&poll->wait.entry); if (poll->wait.private) refcount_dec(&req->refs); poll->head = NULL; spin_unlock(&head->lock); } } static void io_poll_complete(struct io_kiocb *req, __poll_t mask, int error) { struct io_ring_ctx *ctx = req->ctx; io_poll_remove_double(req); req->poll.done = true; io_cqring_fill_event(req, error ? error : mangle_poll(mask)); io_commit_cqring(ctx); } static void io_poll_task_handler(struct io_kiocb *req, struct io_kiocb **nxt) { struct io_ring_ctx *ctx = req->ctx; if (io_poll_rewait(req, &req->poll)) { spin_unlock_irq(&ctx->completion_lock); return; } hash_del(&req->hash_node); io_poll_complete(req, req->result, 0); req->flags |= REQ_F_COMP_LOCKED; *nxt = io_put_req_find_next(req); spin_unlock_irq(&ctx->completion_lock); io_cqring_ev_posted(ctx); } static void io_poll_task_func(struct callback_head *cb) { struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work); struct io_ring_ctx *ctx = req->ctx; struct io_kiocb *nxt = NULL; io_poll_task_handler(req, &nxt); if (nxt) __io_req_task_submit(nxt); percpu_ref_put(&ctx->refs); } static int io_poll_double_wake(struct wait_queue_entry *wait, unsigned mode, int sync, void *key) { struct io_kiocb *req = wait->private; struct io_poll_iocb *poll = io_poll_get_single(req); __poll_t mask = key_to_poll(key); /* for instances that support it check for an event match first: */ if (mask && !(mask & poll->events)) return 0; list_del_init(&wait->entry); if (poll && poll->head) { bool done; spin_lock(&poll->head->lock); done = list_empty(&poll->wait.entry); if (!done) list_del_init(&poll->wait.entry); /* make sure double remove sees this as being gone */ wait->private = NULL; spin_unlock(&poll->head->lock); if (!done) __io_async_wake(req, poll, mask, io_poll_task_func); } refcount_dec(&req->refs); return 1; } static void io_init_poll_iocb(struct io_poll_iocb *poll, __poll_t events, wait_queue_func_t wake_func) { poll->head = NULL; poll->done = false; poll->canceled = false; poll->events = events; INIT_LIST_HEAD(&poll->wait.entry); init_waitqueue_func_entry(&poll->wait, wake_func); } static void __io_queue_proc(struct io_poll_iocb *poll, struct io_poll_table *pt, struct wait_queue_head *head, struct io_poll_iocb **poll_ptr) { struct io_kiocb *req = pt->req; /* * If poll->head is already set, it's because the file being polled * uses multiple waitqueues for poll handling (eg one for read, one * for write). Setup a separate io_poll_iocb if this happens. */ if (unlikely(poll->head)) { /* already have a 2nd entry, fail a third attempt */ if (*poll_ptr) { pt->error = -EINVAL; return; } poll = kmalloc(sizeof(*poll), GFP_ATOMIC); if (!poll) { pt->error = -ENOMEM; return; } io_init_poll_iocb(poll, req->poll.events, io_poll_double_wake); refcount_inc(&req->refs); poll->wait.private = req; *poll_ptr = poll; } pt->error = 0; poll->head = head; if (poll->events & EPOLLEXCLUSIVE) add_wait_queue_exclusive(head, &poll->wait); else add_wait_queue(head, &poll->wait); } static void io_async_queue_proc(struct file *file, struct wait_queue_head *head, struct poll_table_struct *p) { struct io_poll_table *pt = container_of(p, struct io_poll_table, pt); struct async_poll *apoll = pt->req->apoll; __io_queue_proc(&apoll->poll, pt, head, &apoll->double_poll); } static void io_async_task_func(struct callback_head *cb) { struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work); struct async_poll *apoll = req->apoll; struct io_ring_ctx *ctx = req->ctx; trace_io_uring_task_run(req->ctx, req->opcode, req->user_data); if (io_poll_rewait(req, &apoll->poll)) { spin_unlock_irq(&ctx->completion_lock); percpu_ref_put(&ctx->refs); return; } /* If req is still hashed, it cannot have been canceled. Don't check. */ if (hash_hashed(&req->hash_node)) hash_del(&req->hash_node); io_poll_remove_double(req); spin_unlock_irq(&ctx->completion_lock); if (!READ_ONCE(apoll->poll.canceled)) __io_req_task_submit(req); else __io_req_task_cancel(req, -ECANCELED); percpu_ref_put(&ctx->refs); kfree(apoll->double_poll); kfree(apoll); } static int io_async_wake(struct wait_queue_entry *wait, unsigned mode, int sync, void *key) { struct io_kiocb *req = wait->private; struct io_poll_iocb *poll = &req->apoll->poll; trace_io_uring_poll_wake(req->ctx, req->opcode, req->user_data, key_to_poll(key)); return __io_async_wake(req, poll, key_to_poll(key), io_async_task_func); } static void io_poll_req_insert(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; struct hlist_head *list; list = &ctx->cancel_hash[hash_long(req->user_data, ctx->cancel_hash_bits)]; hlist_add_head(&req->hash_node, list); } static __poll_t __io_arm_poll_handler(struct io_kiocb *req, struct io_poll_iocb *poll, struct io_poll_table *ipt, __poll_t mask, wait_queue_func_t wake_func) __acquires(&ctx->completion_lock) { struct io_ring_ctx *ctx = req->ctx; bool cancel = false; io_init_poll_iocb(poll, mask, wake_func); poll->file = req->file; poll->wait.private = req; ipt->pt._key = mask; ipt->req = req; ipt->error = -EINVAL; mask = vfs_poll(req->file, &ipt->pt) & poll->events; spin_lock_irq(&ctx->completion_lock); if (likely(poll->head)) { spin_lock(&poll->head->lock); if (unlikely(list_empty(&poll->wait.entry))) { if (ipt->error) cancel = true; ipt->error = 0; mask = 0; } if (mask || ipt->error) list_del_init(&poll->wait.entry); else if (cancel) WRITE_ONCE(poll->canceled, true); else if (!poll->done) /* actually waiting for an event */ io_poll_req_insert(req); spin_unlock(&poll->head->lock); } return mask; } static bool io_arm_poll_handler(struct io_kiocb *req) { const struct io_op_def *def = &io_op_defs[req->opcode]; struct io_ring_ctx *ctx = req->ctx; struct async_poll *apoll; struct io_poll_table ipt; __poll_t mask, ret; int rw; if (!req->file || !file_can_poll(req->file)) return false; if (req->flags & REQ_F_POLLED) return false; if (def->pollin) rw = READ; else if (def->pollout) rw = WRITE; else return false; /* if we can't nonblock try, then no point in arming a poll handler */ if (!io_file_supports_async(req->file, rw)) return false; apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC); if (unlikely(!apoll)) return false; apoll->double_poll = NULL; req->flags |= REQ_F_POLLED; io_get_req_task(req); req->apoll = apoll; INIT_HLIST_NODE(&req->hash_node); mask = 0; if (def->pollin) mask |= POLLIN | POLLRDNORM; if (def->pollout) mask |= POLLOUT | POLLWRNORM; /* If reading from MSG_ERRQUEUE using recvmsg, ignore POLLIN */ if ((req->opcode == IORING_OP_RECVMSG) && (req->sr_msg.msg_flags & MSG_ERRQUEUE)) mask &= ~POLLIN; mask |= POLLERR | POLLPRI; ipt.pt._qproc = io_async_queue_proc; ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask, io_async_wake); if (ret || ipt.error) { io_poll_remove_double(req); spin_unlock_irq(&ctx->completion_lock); kfree(apoll->double_poll); kfree(apoll); return false; } spin_unlock_irq(&ctx->completion_lock); trace_io_uring_poll_arm(ctx, req->opcode, req->user_data, mask, apoll->poll.events); return true; } static bool __io_poll_remove_one(struct io_kiocb *req, struct io_poll_iocb *poll) { bool do_complete = false; spin_lock(&poll->head->lock); WRITE_ONCE(poll->canceled, true); if (!list_empty(&poll->wait.entry)) { list_del_init(&poll->wait.entry); do_complete = true; } spin_unlock(&poll->head->lock); hash_del(&req->hash_node); return do_complete; } static bool io_poll_remove_one(struct io_kiocb *req) { bool do_complete; io_poll_remove_double(req); if (req->opcode == IORING_OP_POLL_ADD) { do_complete = __io_poll_remove_one(req, &req->poll); } else { struct async_poll *apoll = req->apoll; /* non-poll requests have submit ref still */ do_complete = __io_poll_remove_one(req, &apoll->poll); if (do_complete) { io_put_req(req); kfree(apoll->double_poll); kfree(apoll); } } if (do_complete) { io_cqring_fill_event(req, -ECANCELED); io_commit_cqring(req->ctx); req->flags |= REQ_F_COMP_LOCKED; req_set_fail_links(req); io_put_req(req); } return do_complete; } static void io_poll_remove_all(struct io_ring_ctx *ctx) { struct hlist_node *tmp; struct io_kiocb *req; int posted = 0, i; spin_lock_irq(&ctx->completion_lock); for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) { struct hlist_head *list; list = &ctx->cancel_hash[i]; hlist_for_each_entry_safe(req, tmp, list, hash_node) posted += io_poll_remove_one(req); } spin_unlock_irq(&ctx->completion_lock); if (posted) io_cqring_ev_posted(ctx); } static int io_poll_cancel(struct io_ring_ctx *ctx, __u64 sqe_addr) { struct hlist_head *list; struct io_kiocb *req; list = &ctx->cancel_hash[hash_long(sqe_addr, ctx->cancel_hash_bits)]; hlist_for_each_entry(req, list, hash_node) { if (sqe_addr != req->user_data) continue; if (io_poll_remove_one(req)) return 0; return -EALREADY; } return -ENOENT; } static int io_poll_remove_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->ioprio || sqe->off || sqe->len || sqe->buf_index || sqe->poll_events) return -EINVAL; req->poll.addr = READ_ONCE(sqe->addr); return 0; } /* * Find a running poll command that matches one specified in sqe->addr, * and remove it if found. */ static int io_poll_remove(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; u64 addr; int ret; addr = req->poll.addr; spin_lock_irq(&ctx->completion_lock); ret = io_poll_cancel(ctx, addr); spin_unlock_irq(&ctx->completion_lock); if (ret < 0) req_set_fail_links(req); io_req_complete(req, ret); return 0; } static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync, void *key) { struct io_kiocb *req = wait->private; struct io_poll_iocb *poll = &req->poll; return __io_async_wake(req, poll, key_to_poll(key), io_poll_task_func); } static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head, struct poll_table_struct *p) { struct io_poll_table *pt = container_of(p, struct io_poll_table, pt); __io_queue_proc(&pt->req->poll, pt, head, (struct io_poll_iocb **) &pt->req->io); } static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_poll_iocb *poll = &req->poll; u32 events; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->addr || sqe->ioprio || sqe->off || sqe->len || sqe->buf_index) return -EINVAL; if (!poll->file) return -EBADF; events = READ_ONCE(sqe->poll32_events); #ifdef __BIG_ENDIAN events = swahw32(events); #endif poll->events = demangle_poll(events) | EPOLLERR | EPOLLHUP | (events & EPOLLEXCLUSIVE); io_get_req_task(req); return 0; } static int io_poll_add(struct io_kiocb *req) { struct io_poll_iocb *poll = &req->poll; struct io_ring_ctx *ctx = req->ctx; struct io_poll_table ipt; __poll_t mask; INIT_HLIST_NODE(&req->hash_node); ipt.pt._qproc = io_poll_queue_proc; mask = __io_arm_poll_handler(req, &req->poll, &ipt, poll->events, io_poll_wake); if (mask) { /* no async, we'd stolen it */ ipt.error = 0; io_poll_complete(req, mask, 0); } spin_unlock_irq(&ctx->completion_lock); if (mask) { io_cqring_ev_posted(ctx); io_put_req(req); } return ipt.error; } static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer) { struct io_timeout_data *data = container_of(timer, struct io_timeout_data, timer); struct io_kiocb *req = data->req; struct io_ring_ctx *ctx = req->ctx; unsigned long flags; spin_lock_irqsave(&ctx->completion_lock, flags); atomic_set(&req->ctx->cq_timeouts, atomic_read(&req->ctx->cq_timeouts) + 1); /* * We could be racing with timeout deletion. If the list is empty, * then timeout lookup already found it and will be handling it. */ if (!list_empty(&req->timeout.list)) list_del_init(&req->timeout.list); io_cqring_fill_event(req, -ETIME); io_commit_cqring(ctx); spin_unlock_irqrestore(&ctx->completion_lock, flags); io_cqring_ev_posted(ctx); req_set_fail_links(req); io_put_req(req); return HRTIMER_NORESTART; } static int __io_timeout_cancel(struct io_kiocb *req) { int ret; list_del_init(&req->timeout.list); ret = hrtimer_try_to_cancel(&req->io->timeout.timer); if (ret == -1) return -EALREADY; req_set_fail_links(req); req->flags |= REQ_F_COMP_LOCKED; io_cqring_fill_event(req, -ECANCELED); io_put_req(req); return 0; } static int io_timeout_cancel(struct io_ring_ctx *ctx, __u64 user_data) { struct io_kiocb *req; int ret = -ENOENT; list_for_each_entry(req, &ctx->timeout_list, timeout.list) { if (user_data == req->user_data) { ret = 0; break; } } if (ret == -ENOENT) return ret; return __io_timeout_cancel(req); } static int io_timeout_remove_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT))) return -EINVAL; if (sqe->ioprio || sqe->buf_index || sqe->len) return -EINVAL; req->timeout.addr = READ_ONCE(sqe->addr); req->timeout.flags = READ_ONCE(sqe->timeout_flags); if (req->timeout.flags) return -EINVAL; return 0; } /* * Remove or update an existing timeout command */ static int io_timeout_remove(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; int ret; spin_lock_irq(&ctx->completion_lock); ret = io_timeout_cancel(ctx, req->timeout.addr); io_cqring_fill_event(req, ret); io_commit_cqring(ctx); spin_unlock_irq(&ctx->completion_lock); io_cqring_ev_posted(ctx); if (ret < 0) req_set_fail_links(req); io_put_req(req); return 0; } static int io_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe, bool is_timeout_link) { struct io_timeout_data *data; unsigned flags; u32 off = READ_ONCE(sqe->off); if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->ioprio || sqe->buf_index || sqe->len != 1) return -EINVAL; if (off && is_timeout_link) return -EINVAL; flags = READ_ONCE(sqe->timeout_flags); if (flags & ~IORING_TIMEOUT_ABS) return -EINVAL; req->timeout.off = off; if (!req->io && io_alloc_async_ctx(req)) return -ENOMEM; data = &req->io->timeout; data->req = req; if (get_timespec64(&data->ts, u64_to_user_ptr(sqe->addr))) return -EFAULT; if (flags & IORING_TIMEOUT_ABS) data->mode = HRTIMER_MODE_ABS; else data->mode = HRTIMER_MODE_REL; hrtimer_init(&data->timer, CLOCK_MONOTONIC, data->mode); return 0; } static int io_timeout(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; struct io_timeout_data *data = &req->io->timeout; struct list_head *entry; u32 tail, off = req->timeout.off; spin_lock_irq(&ctx->completion_lock); /* * sqe->off holds how many events that need to occur for this * timeout event to be satisfied. If it isn't set, then this is * a pure timeout request, sequence isn't used. */ if (io_is_timeout_noseq(req)) { entry = ctx->timeout_list.prev; goto add; } tail = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts); req->timeout.target_seq = tail + off; /* * Insertion sort, ensuring the first entry in the list is always * the one we need first. */ list_for_each_prev(entry, &ctx->timeout_list) { struct io_kiocb *nxt = list_entry(entry, struct io_kiocb, timeout.list); if (io_is_timeout_noseq(nxt)) continue; /* nxt.seq is behind @tail, otherwise would've been completed */ if (off >= nxt->timeout.target_seq - tail) break; } add: list_add(&req->timeout.list, entry); data->timer.function = io_timeout_fn; hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode); spin_unlock_irq(&ctx->completion_lock); return 0; } static bool io_cancel_cb(struct io_wq_work *work, void *data) { struct io_kiocb *req = container_of(work, struct io_kiocb, work); return req->user_data == (unsigned long) data; } static int io_async_cancel_one(struct io_ring_ctx *ctx, void *sqe_addr) { enum io_wq_cancel cancel_ret; int ret = 0; cancel_ret = io_wq_cancel_cb(ctx->io_wq, io_cancel_cb, sqe_addr, false); switch (cancel_ret) { case IO_WQ_CANCEL_OK: ret = 0; break; case IO_WQ_CANCEL_RUNNING: ret = -EALREADY; break; case IO_WQ_CANCEL_NOTFOUND: ret = -ENOENT; break; } return ret; } static void io_async_find_and_cancel(struct io_ring_ctx *ctx, struct io_kiocb *req, __u64 sqe_addr, int success_ret) { unsigned long flags; int ret; ret = io_async_cancel_one(ctx, (void *) (unsigned long) sqe_addr); if (ret != -ENOENT) { spin_lock_irqsave(&ctx->completion_lock, flags); goto done; } spin_lock_irqsave(&ctx->completion_lock, flags); ret = io_timeout_cancel(ctx, sqe_addr); if (ret != -ENOENT) goto done; ret = io_poll_cancel(ctx, sqe_addr); done: if (!ret) ret = success_ret; io_cqring_fill_event(req, ret); io_commit_cqring(ctx); spin_unlock_irqrestore(&ctx->completion_lock, flags); io_cqring_ev_posted(ctx); if (ret < 0) req_set_fail_links(req); io_put_req(req); } static int io_async_cancel_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT))) return -EINVAL; if (sqe->ioprio || sqe->off || sqe->len || sqe->cancel_flags) return -EINVAL; req->cancel.addr = READ_ONCE(sqe->addr); return 0; } static int io_async_cancel(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; io_async_find_and_cancel(ctx, req, req->cancel.addr, 0); return 0; } static int io_files_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (unlikely(req->ctx->flags & IORING_SETUP_SQPOLL)) return -EINVAL; if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT))) return -EINVAL; if (sqe->ioprio || sqe->rw_flags) return -EINVAL; req->files_update.offset = READ_ONCE(sqe->off); req->files_update.nr_args = READ_ONCE(sqe->len); if (!req->files_update.nr_args) return -EINVAL; req->files_update.arg = READ_ONCE(sqe->addr); return 0; } static int io_files_update(struct io_kiocb *req, bool force_nonblock, struct io_comp_state *cs) { struct io_ring_ctx *ctx = req->ctx; struct io_uring_files_update up; int ret; if (force_nonblock) return -EAGAIN; up.offset = req->files_update.offset; up.fds = req->files_update.arg; mutex_lock(&ctx->uring_lock); ret = __io_sqe_files_update(ctx, &up, req->files_update.nr_args); mutex_unlock(&ctx->uring_lock); if (ret < 0) req_set_fail_links(req); __io_req_complete(req, ret, 0, cs); return 0; } static int io_req_defer_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { ssize_t ret = 0; if (!sqe) return 0; if (io_alloc_async_ctx(req)) return -EAGAIN; ret = io_prep_work_files(req); if (unlikely(ret)) return ret; io_prep_async_work(req); switch (req->opcode) { case IORING_OP_NOP: break; case IORING_OP_READV: case IORING_OP_READ_FIXED: case IORING_OP_READ: ret = io_read_prep(req, sqe, true); break; case IORING_OP_WRITEV: case IORING_OP_WRITE_FIXED: case IORING_OP_WRITE: ret = io_write_prep(req, sqe, true); break; case IORING_OP_POLL_ADD: ret = io_poll_add_prep(req, sqe); break; case IORING_OP_POLL_REMOVE: ret = io_poll_remove_prep(req, sqe); break; case IORING_OP_FSYNC: ret = io_prep_fsync(req, sqe); break; case IORING_OP_SYNC_FILE_RANGE: ret = io_prep_sfr(req, sqe); break; case IORING_OP_SENDMSG: case IORING_OP_SEND: ret = io_sendmsg_prep(req, sqe); break; case IORING_OP_RECVMSG: case IORING_OP_RECV: ret = io_recvmsg_prep(req, sqe); break; case IORING_OP_CONNECT: ret = io_connect_prep(req, sqe); break; case IORING_OP_TIMEOUT: ret = io_timeout_prep(req, sqe, false); break; case IORING_OP_TIMEOUT_REMOVE: ret = io_timeout_remove_prep(req, sqe); break; case IORING_OP_ASYNC_CANCEL: ret = io_async_cancel_prep(req, sqe); break; case IORING_OP_LINK_TIMEOUT: ret = io_timeout_prep(req, sqe, true); break; case IORING_OP_ACCEPT: ret = io_accept_prep(req, sqe); break; case IORING_OP_FALLOCATE: ret = io_fallocate_prep(req, sqe); break; case IORING_OP_OPENAT: ret = io_openat_prep(req, sqe); break; case IORING_OP_CLOSE: ret = io_close_prep(req, sqe); break; case IORING_OP_FILES_UPDATE: ret = io_files_update_prep(req, sqe); break; case IORING_OP_STATX: ret = io_statx_prep(req, sqe); break; case IORING_OP_FADVISE: ret = io_fadvise_prep(req, sqe); break; case IORING_OP_MADVISE: ret = io_madvise_prep(req, sqe); break; case IORING_OP_OPENAT2: ret = io_openat2_prep(req, sqe); break; case IORING_OP_EPOLL_CTL: ret = io_epoll_ctl_prep(req, sqe); break; case IORING_OP_SPLICE: ret = io_splice_prep(req, sqe); break; case IORING_OP_PROVIDE_BUFFERS: ret = io_provide_buffers_prep(req, sqe); break; case IORING_OP_REMOVE_BUFFERS: ret = io_remove_buffers_prep(req, sqe); break; case IORING_OP_TEE: ret = io_tee_prep(req, sqe); break; default: printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n", req->opcode); ret = -EINVAL; break; } return ret; } static u32 io_get_sequence(struct io_kiocb *req) { struct io_kiocb *pos; struct io_ring_ctx *ctx = req->ctx; u32 total_submitted, nr_reqs = 1; if (req->flags & REQ_F_LINK_HEAD) list_for_each_entry(pos, &req->link_list, link_list) nr_reqs++; total_submitted = ctx->cached_sq_head - ctx->cached_sq_dropped; return total_submitted - nr_reqs; } static int io_req_defer(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_ring_ctx *ctx = req->ctx; struct io_defer_entry *de; int ret; u32 seq; /* Still need defer if there is pending req in defer list. */ if (likely(list_empty_careful(&ctx->defer_list) && !(req->flags & REQ_F_IO_DRAIN))) return 0; seq = io_get_sequence(req); /* Still a chance to pass the sequence check */ if (!req_need_defer(req, seq) && list_empty_careful(&ctx->defer_list)) return 0; if (!req->io) { ret = io_req_defer_prep(req, sqe); if (ret) return ret; } io_prep_async_link(req); de = kmalloc(sizeof(*de), GFP_KERNEL); if (!de) return -ENOMEM; spin_lock_irq(&ctx->completion_lock); if (!req_need_defer(req, seq) && list_empty(&ctx->defer_list)) { spin_unlock_irq(&ctx->completion_lock); kfree(de); io_queue_async_work(req); return -EIOCBQUEUED; } trace_io_uring_defer(ctx, req, req->user_data); de->req = req; de->seq = seq; list_add_tail(&de->list, &ctx->defer_list); spin_unlock_irq(&ctx->completion_lock); return -EIOCBQUEUED; } static void __io_clean_op(struct io_kiocb *req) { struct io_async_ctx *io = req->io; if (req->flags & REQ_F_BUFFER_SELECTED) { switch (req->opcode) { case IORING_OP_READV: case IORING_OP_READ_FIXED: case IORING_OP_READ: kfree((void *)(unsigned long)req->rw.addr); break; case IORING_OP_RECVMSG: case IORING_OP_RECV: kfree(req->sr_msg.kbuf); break; } req->flags &= ~REQ_F_BUFFER_SELECTED; } if (req->flags & REQ_F_NEED_CLEANUP) { switch (req->opcode) { case IORING_OP_READV: case IORING_OP_READ_FIXED: case IORING_OP_READ: case IORING_OP_WRITEV: case IORING_OP_WRITE_FIXED: case IORING_OP_WRITE: if (io->rw.free_iovec) kfree(io->rw.free_iovec); break; case IORING_OP_RECVMSG: case IORING_OP_SENDMSG: if (io->msg.iov != io->msg.fast_iov) kfree(io->msg.iov); break; case IORING_OP_SPLICE: case IORING_OP_TEE: io_put_file(req, req->splice.file_in, (req->splice.flags & SPLICE_F_FD_IN_FIXED)); break; case IORING_OP_OPENAT: case IORING_OP_OPENAT2: if (req->open.filename) putname(req->open.filename); break; } req->flags &= ~REQ_F_NEED_CLEANUP; } if (req->flags & REQ_F_INFLIGHT) { struct io_ring_ctx *ctx = req->ctx; unsigned long flags; spin_lock_irqsave(&ctx->inflight_lock, flags); list_del(&req->inflight_entry); if (waitqueue_active(&ctx->inflight_wait)) wake_up(&ctx->inflight_wait); spin_unlock_irqrestore(&ctx->inflight_lock, flags); req->flags &= ~REQ_F_INFLIGHT; } } static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe, bool force_nonblock, struct io_comp_state *cs) { struct io_ring_ctx *ctx = req->ctx; int ret; switch (req->opcode) { case IORING_OP_NOP: ret = io_nop(req, cs); break; case IORING_OP_READV: case IORING_OP_READ_FIXED: case IORING_OP_READ: if (sqe) { ret = io_read_prep(req, sqe, force_nonblock); if (ret < 0) break; } ret = io_read(req, force_nonblock, cs); break; case IORING_OP_WRITEV: case IORING_OP_WRITE_FIXED: case IORING_OP_WRITE: if (sqe) { ret = io_write_prep(req, sqe, force_nonblock); if (ret < 0) break; } ret = io_write(req, force_nonblock, cs); break; case IORING_OP_FSYNC: if (sqe) { ret = io_prep_fsync(req, sqe); if (ret < 0) break; } ret = io_fsync(req, force_nonblock); break; case IORING_OP_POLL_ADD: if (sqe) { ret = io_poll_add_prep(req, sqe); if (ret) break; } ret = io_poll_add(req); break; case IORING_OP_POLL_REMOVE: if (sqe) { ret = io_poll_remove_prep(req, sqe); if (ret < 0) break; } ret = io_poll_remove(req); break; case IORING_OP_SYNC_FILE_RANGE: if (sqe) { ret = io_prep_sfr(req, sqe); if (ret < 0) break; } ret = io_sync_file_range(req, force_nonblock); break; case IORING_OP_SENDMSG: case IORING_OP_SEND: if (sqe) { ret = io_sendmsg_prep(req, sqe); if (ret < 0) break; } if (req->opcode == IORING_OP_SENDMSG) ret = io_sendmsg(req, force_nonblock, cs); else ret = io_send(req, force_nonblock, cs); break; case IORING_OP_RECVMSG: case IORING_OP_RECV: if (sqe) { ret = io_recvmsg_prep(req, sqe); if (ret) break; } if (req->opcode == IORING_OP_RECVMSG) ret = io_recvmsg(req, force_nonblock, cs); else ret = io_recv(req, force_nonblock, cs); break; case IORING_OP_TIMEOUT: if (sqe) { ret = io_timeout_prep(req, sqe, false); if (ret) break; } ret = io_timeout(req); break; case IORING_OP_TIMEOUT_REMOVE: if (sqe) { ret = io_timeout_remove_prep(req, sqe); if (ret) break; } ret = io_timeout_remove(req); break; case IORING_OP_ACCEPT: if (sqe) { ret = io_accept_prep(req, sqe); if (ret) break; } ret = io_accept(req, force_nonblock, cs); break; case IORING_OP_CONNECT: if (sqe) { ret = io_connect_prep(req, sqe); if (ret) break; } ret = io_connect(req, force_nonblock, cs); break; case IORING_OP_ASYNC_CANCEL: if (sqe) { ret = io_async_cancel_prep(req, sqe); if (ret) break; } ret = io_async_cancel(req); break; case IORING_OP_FALLOCATE: if (sqe) { ret = io_fallocate_prep(req, sqe); if (ret) break; } ret = io_fallocate(req, force_nonblock); break; case IORING_OP_OPENAT: if (sqe) { ret = io_openat_prep(req, sqe); if (ret) break; } ret = io_openat(req, force_nonblock); break; case IORING_OP_CLOSE: if (sqe) { ret = io_close_prep(req, sqe); if (ret) break; } ret = io_close(req, force_nonblock, cs); break; case IORING_OP_FILES_UPDATE: if (sqe) { ret = io_files_update_prep(req, sqe); if (ret) break; } ret = io_files_update(req, force_nonblock, cs); break; case IORING_OP_STATX: if (sqe) { ret = io_statx_prep(req, sqe); if (ret) break; } ret = io_statx(req, force_nonblock); break; case IORING_OP_FADVISE: if (sqe) { ret = io_fadvise_prep(req, sqe); if (ret) break; } ret = io_fadvise(req, force_nonblock); break; case IORING_OP_MADVISE: if (sqe) { ret = io_madvise_prep(req, sqe); if (ret) break; } ret = io_madvise(req, force_nonblock); break; case IORING_OP_OPENAT2: if (sqe) { ret = io_openat2_prep(req, sqe); if (ret) break; } ret = io_openat2(req, force_nonblock); break; case IORING_OP_EPOLL_CTL: if (sqe) { ret = io_epoll_ctl_prep(req, sqe); if (ret) break; } ret = io_epoll_ctl(req, force_nonblock, cs); break; case IORING_OP_SPLICE: if (sqe) { ret = io_splice_prep(req, sqe); if (ret < 0) break; } ret = io_splice(req, force_nonblock); break; case IORING_OP_PROVIDE_BUFFERS: if (sqe) { ret = io_provide_buffers_prep(req, sqe); if (ret) break; } ret = io_provide_buffers(req, force_nonblock, cs); break; case IORING_OP_REMOVE_BUFFERS: if (sqe) { ret = io_remove_buffers_prep(req, sqe); if (ret) break; } ret = io_remove_buffers(req, force_nonblock, cs); break; case IORING_OP_TEE: if (sqe) { ret = io_tee_prep(req, sqe); if (ret < 0) break; } ret = io_tee(req, force_nonblock); break; default: ret = -EINVAL; break; } if (ret) return ret; /* If the op doesn't have a file, we're not polling for it */ if ((ctx->flags & IORING_SETUP_IOPOLL) && req->file) { const bool in_async = io_wq_current_is_worker(); /* workqueue context doesn't hold uring_lock, grab it now */ if (in_async) mutex_lock(&ctx->uring_lock); io_iopoll_req_issued(req); if (in_async) mutex_unlock(&ctx->uring_lock); } return 0; } static struct io_wq_work *io_wq_submit_work(struct io_wq_work *work) { struct io_kiocb *req = container_of(work, struct io_kiocb, work); struct io_kiocb *timeout; int ret = 0; timeout = io_prep_linked_timeout(req); if (timeout) io_queue_linked_timeout(timeout); /* if NO_CANCEL is set, we must still run the work */ if ((work->flags & (IO_WQ_WORK_CANCEL|IO_WQ_WORK_NO_CANCEL)) == IO_WQ_WORK_CANCEL) { ret = -ECANCELED; } if (!ret) { do { ret = io_issue_sqe(req, NULL, false, NULL); /* * We can get EAGAIN for polled IO even though we're * forcing a sync submission from here, since we can't * wait for request slots on the block side. */ if (ret != -EAGAIN) break; cond_resched(); } while (1); } if (ret) { req_set_fail_links(req); io_req_complete(req, ret); } return io_steal_work(req); } static inline struct file *io_file_from_index(struct io_ring_ctx *ctx, int index) { struct fixed_file_table *table; table = &ctx->file_data->table[index >> IORING_FILE_TABLE_SHIFT]; return table->files[index & IORING_FILE_TABLE_MASK]; } static int io_file_get(struct io_submit_state *state, struct io_kiocb *req, int fd, struct file **out_file, bool fixed) { struct io_ring_ctx *ctx = req->ctx; struct file *file; if (fixed) { if (unlikely(!ctx->file_data || (unsigned) fd >= ctx->nr_user_files)) return -EBADF; fd = array_index_nospec(fd, ctx->nr_user_files); file = io_file_from_index(ctx, fd); if (file) { req->fixed_file_refs = ctx->file_data->cur_refs; percpu_ref_get(req->fixed_file_refs); } } else { trace_io_uring_file_get(ctx, fd); file = __io_file_get(state, fd); } if (file || io_op_defs[req->opcode].needs_file_no_error) { *out_file = file; return 0; } return -EBADF; } static int io_req_set_file(struct io_submit_state *state, struct io_kiocb *req, int fd) { bool fixed; fixed = (req->flags & REQ_F_FIXED_FILE) != 0; if (unlikely(!fixed && io_async_submit(req->ctx))) return -EBADF; return io_file_get(state, req, fd, &req->file, fixed); } static int io_grab_files(struct io_kiocb *req) { int ret = -EBADF; struct io_ring_ctx *ctx = req->ctx; io_req_init_async(req); if (req->work.files || (req->flags & REQ_F_NO_FILE_TABLE)) return 0; if (!ctx->ring_file) return -EBADF; rcu_read_lock(); spin_lock_irq(&ctx->inflight_lock); /* * We use the f_ops->flush() handler to ensure that we can flush * out work accessing these files if the fd is closed. Check if * the fd has changed since we started down this path, and disallow * this operation if it has. */ if (fcheck(ctx->ring_fd) == ctx->ring_file) { list_add(&req->inflight_entry, &ctx->inflight_list); req->flags |= REQ_F_INFLIGHT; req->work.files = current->files; ret = 0; } spin_unlock_irq(&ctx->inflight_lock); rcu_read_unlock(); return ret; } static inline int io_prep_work_files(struct io_kiocb *req) { if (!io_op_defs[req->opcode].file_table) return 0; return io_grab_files(req); } static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer) { struct io_timeout_data *data = container_of(timer, struct io_timeout_data, timer); struct io_kiocb *req = data->req; struct io_ring_ctx *ctx = req->ctx; struct io_kiocb *prev = NULL; unsigned long flags; spin_lock_irqsave(&ctx->completion_lock, flags); /* * We don't expect the list to be empty, that will only happen if we * race with the completion of the linked work. */ if (!list_empty(&req->link_list)) { prev = list_entry(req->link_list.prev, struct io_kiocb, link_list); if (refcount_inc_not_zero(&prev->refs)) { list_del_init(&req->link_list); prev->flags &= ~REQ_F_LINK_TIMEOUT; } else prev = NULL; } spin_unlock_irqrestore(&ctx->completion_lock, flags); if (prev) { req_set_fail_links(prev); io_async_find_and_cancel(ctx, req, prev->user_data, -ETIME); io_put_req(prev); } else { io_req_complete(req, -ETIME); } return HRTIMER_NORESTART; } static void __io_queue_linked_timeout(struct io_kiocb *req) { /* * If the list is now empty, then our linked request finished before * we got a chance to setup the timer */ if (!list_empty(&req->link_list)) { struct io_timeout_data *data = &req->io->timeout; data->timer.function = io_link_timeout_fn; hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode); } } static void io_queue_linked_timeout(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; spin_lock_irq(&ctx->completion_lock); __io_queue_linked_timeout(req); spin_unlock_irq(&ctx->completion_lock); /* drop submission reference */ io_put_req(req); } static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req) { struct io_kiocb *nxt; if (!(req->flags & REQ_F_LINK_HEAD)) return NULL; if (req->flags & REQ_F_LINK_TIMEOUT) return NULL; nxt = list_first_entry_or_null(&req->link_list, struct io_kiocb, link_list); if (!nxt || nxt->opcode != IORING_OP_LINK_TIMEOUT) return NULL; req->flags |= REQ_F_LINK_TIMEOUT; return nxt; } static void __io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe, struct io_comp_state *cs) { struct io_kiocb *linked_timeout; struct io_kiocb *nxt; const struct cred *old_creds = NULL; int ret; again: linked_timeout = io_prep_linked_timeout(req); if ((req->flags & REQ_F_WORK_INITIALIZED) && req->work.creds && req->work.creds != current_cred()) { if (old_creds) revert_creds(old_creds); if (old_creds == req->work.creds) old_creds = NULL; /* restored original creds */ else old_creds = override_creds(req->work.creds); } ret = io_issue_sqe(req, sqe, true, cs); /* * We async punt it if the file wasn't marked NOWAIT, or if the file * doesn't support non-blocking read/write attempts */ if (ret == -EAGAIN && !(req->flags & REQ_F_NOWAIT)) { if (!io_arm_poll_handler(req)) { punt: ret = io_prep_work_files(req); if (unlikely(ret)) goto err; /* * Queued up for async execution, worker will release * submit reference when the iocb is actually submitted. */ io_queue_async_work(req); } if (linked_timeout) io_queue_linked_timeout(linked_timeout); goto exit; } if (unlikely(ret)) { err: /* un-prep timeout, so it'll be killed as any other linked */ req->flags &= ~REQ_F_LINK_TIMEOUT; req_set_fail_links(req); io_put_req(req); io_req_complete(req, ret); goto exit; } /* drop submission reference */ nxt = io_put_req_find_next(req); if (linked_timeout) io_queue_linked_timeout(linked_timeout); if (nxt) { req = nxt; if (req->flags & REQ_F_FORCE_ASYNC) goto punt; goto again; } exit: if (old_creds) revert_creds(old_creds); } static void io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe, struct io_comp_state *cs) { int ret; ret = io_req_defer(req, sqe); if (ret) { if (ret != -EIOCBQUEUED) { fail_req: req_set_fail_links(req); io_put_req(req); io_req_complete(req, ret); } } else if (req->flags & REQ_F_FORCE_ASYNC) { if (!req->io) { ret = io_req_defer_prep(req, sqe); if (unlikely(ret)) goto fail_req; } /* * Never try inline submit of IOSQE_ASYNC is set, go straight * to async execution. */ io_req_init_async(req); req->work.flags |= IO_WQ_WORK_CONCURRENT; io_queue_async_work(req); } else { __io_queue_sqe(req, sqe, cs); } } static inline void io_queue_link_head(struct io_kiocb *req, struct io_comp_state *cs) { if (unlikely(req->flags & REQ_F_FAIL_LINK)) { io_put_req(req); io_req_complete(req, -ECANCELED); } else io_queue_sqe(req, NULL, cs); } static int io_submit_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe, struct io_kiocb **link, struct io_comp_state *cs) { struct io_ring_ctx *ctx = req->ctx; int ret; /* * If we already have a head request, queue this one for async * submittal once the head completes. If we don't have a head but * IOSQE_IO_LINK is set in the sqe, start a new head. This one will be * submitted sync once the chain is complete. If none of those * conditions are true (normal request), then just queue it. */ if (*link) { struct io_kiocb *head = *link; /* * Taking sequential execution of a link, draining both sides * of the link also fullfils IOSQE_IO_DRAIN semantics for all * requests in the link. So, it drains the head and the * next after the link request. The last one is done via * drain_next flag to persist the effect across calls. */ if (req->flags & REQ_F_IO_DRAIN) { head->flags |= REQ_F_IO_DRAIN; ctx->drain_next = 1; } ret = io_req_defer_prep(req, sqe); if (unlikely(ret)) { /* fail even hard links since we don't submit */ head->flags |= REQ_F_FAIL_LINK; return ret; } trace_io_uring_link(ctx, req, head); io_get_req_task(req); list_add_tail(&req->link_list, &head->link_list); /* last request of a link, enqueue the link */ if (!(req->flags & (REQ_F_LINK | REQ_F_HARDLINK))) { io_queue_link_head(head, cs); *link = NULL; } } else { if (unlikely(ctx->drain_next)) { req->flags |= REQ_F_IO_DRAIN; ctx->drain_next = 0; } if (req->flags & (REQ_F_LINK | REQ_F_HARDLINK)) { req->flags |= REQ_F_LINK_HEAD; INIT_LIST_HEAD(&req->link_list); ret = io_req_defer_prep(req, sqe); if (unlikely(ret)) req->flags |= REQ_F_FAIL_LINK; *link = req; } else { io_queue_sqe(req, sqe, cs); } } return 0; } /* * Batched submission is done, ensure local IO is flushed out. */ static void io_submit_state_end(struct io_submit_state *state) { if (!list_empty(&state->comp.list)) io_submit_flush_completions(&state->comp); blk_finish_plug(&state->plug); io_state_file_put(state); if (state->free_reqs) kmem_cache_free_bulk(req_cachep, state->free_reqs, state->reqs); } /* * Start submission side cache. */ static void io_submit_state_start(struct io_submit_state *state, struct io_ring_ctx *ctx, unsigned int max_ios) { blk_start_plug(&state->plug); state->comp.nr = 0; INIT_LIST_HEAD(&state->comp.list); state->comp.ctx = ctx; state->free_reqs = 0; state->file = NULL; state->ios_left = max_ios; } static void io_commit_sqring(struct io_ring_ctx *ctx) { struct io_rings *rings = ctx->rings; /* * Ensure any loads from the SQEs are done at this point, * since once we write the new head, the application could * write new data to them. */ smp_store_release(&rings->sq.head, ctx->cached_sq_head); } /* * Fetch an sqe, if one is available. Note that sqe_ptr will point to memory * that is mapped by userspace. This means that care needs to be taken to * ensure that reads are stable, as we cannot rely on userspace always * being a good citizen. If members of the sqe are validated and then later * used, it's important that those reads are done through READ_ONCE() to * prevent a re-load down the line. */ static const struct io_uring_sqe *io_get_sqe(struct io_ring_ctx *ctx) { u32 *sq_array = ctx->sq_array; unsigned head; /* * The cached sq head (or cq tail) serves two purposes: * * 1) allows us to batch the cost of updating the user visible * head updates. * 2) allows the kernel side to track the head on its own, even * though the application is the one updating it. */ head = READ_ONCE(sq_array[ctx->cached_sq_head & ctx->sq_mask]); if (likely(head < ctx->sq_entries)) return &ctx->sq_sqes[head]; /* drop invalid entries */ ctx->cached_sq_dropped++; WRITE_ONCE(ctx->rings->sq_dropped, ctx->cached_sq_dropped); return NULL; } static inline void io_consume_sqe(struct io_ring_ctx *ctx) { ctx->cached_sq_head++; } #define SQE_VALID_FLAGS (IOSQE_FIXED_FILE|IOSQE_IO_DRAIN|IOSQE_IO_LINK| \ IOSQE_IO_HARDLINK | IOSQE_ASYNC | \ IOSQE_BUFFER_SELECT) static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req, const struct io_uring_sqe *sqe, struct io_submit_state *state) { unsigned int sqe_flags; int id; req->opcode = READ_ONCE(sqe->opcode); req->user_data = READ_ONCE(sqe->user_data); req->io = NULL; req->file = NULL; req->ctx = ctx; req->flags = 0; /* one is dropped after submission, the other at completion */ refcount_set(&req->refs, 2); req->task = current; req->result = 0; if (unlikely(req->opcode >= IORING_OP_LAST)) return -EINVAL; if (unlikely(io_sq_thread_acquire_mm(ctx, req))) return -EFAULT; sqe_flags = READ_ONCE(sqe->flags); /* enforce forwards compatibility on users */ if (unlikely(sqe_flags & ~SQE_VALID_FLAGS)) return -EINVAL; if ((sqe_flags & IOSQE_BUFFER_SELECT) && !io_op_defs[req->opcode].buffer_select) return -EOPNOTSUPP; id = READ_ONCE(sqe->personality); if (id) { io_req_init_async(req); req->work.creds = idr_find(&ctx->personality_idr, id); if (unlikely(!req->work.creds)) return -EINVAL; get_cred(req->work.creds); } /* same numerical values with corresponding REQ_F_*, safe to copy */ req->flags |= sqe_flags; if (!io_op_defs[req->opcode].needs_file) return 0; return io_req_set_file(state, req, READ_ONCE(sqe->fd)); } static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr, struct file *ring_file, int ring_fd) { struct io_submit_state state; struct io_kiocb *link = NULL; int i, submitted = 0; /* if we have a backlog and couldn't flush it all, return BUSY */ if (test_bit(0, &ctx->sq_check_overflow)) { if (!list_empty(&ctx->cq_overflow_list) && !io_cqring_overflow_flush(ctx, false)) return -EBUSY; } /* make sure SQ entry isn't read before tail */ nr = min3(nr, ctx->sq_entries, io_sqring_entries(ctx)); if (!percpu_ref_tryget_many(&ctx->refs, nr)) return -EAGAIN; io_submit_state_start(&state, ctx, nr); ctx->ring_fd = ring_fd; ctx->ring_file = ring_file; for (i = 0; i < nr; i++) { const struct io_uring_sqe *sqe; struct io_kiocb *req; int err; sqe = io_get_sqe(ctx); if (unlikely(!sqe)) { io_consume_sqe(ctx); break; } req = io_alloc_req(ctx, &state); if (unlikely(!req)) { if (!submitted) submitted = -EAGAIN; break; } err = io_init_req(ctx, req, sqe, &state); io_consume_sqe(ctx); /* will complete beyond this point, count as submitted */ submitted++; if (unlikely(err)) { fail_req: io_put_req(req); io_req_complete(req, err); break; } trace_io_uring_submit_sqe(ctx, req->opcode, req->user_data, true, io_async_submit(ctx)); err = io_submit_sqe(req, sqe, &link, &state.comp); if (err) goto fail_req; } if (unlikely(submitted != nr)) { int ref_used = (submitted == -EAGAIN) ? 0 : submitted; percpu_ref_put_many(&ctx->refs, nr - ref_used); } if (link) io_queue_link_head(link, &state.comp); io_submit_state_end(&state); /* Commit SQ ring head once we've consumed and submitted all SQEs */ io_commit_sqring(ctx); return submitted; } static inline void io_ring_set_wakeup_flag(struct io_ring_ctx *ctx) { /* Tell userspace we may need a wakeup call */ spin_lock_irq(&ctx->completion_lock); ctx->rings->sq_flags |= IORING_SQ_NEED_WAKEUP; spin_unlock_irq(&ctx->completion_lock); } static inline void io_ring_clear_wakeup_flag(struct io_ring_ctx *ctx) { spin_lock_irq(&ctx->completion_lock); ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP; spin_unlock_irq(&ctx->completion_lock); } static int io_sq_thread(void *data) { struct io_ring_ctx *ctx = data; const struct cred *old_cred; DEFINE_WAIT(wait); unsigned long timeout; int ret = 0; complete(&ctx->sq_thread_comp); old_cred = override_creds(ctx->creds); timeout = jiffies + ctx->sq_thread_idle; while (!kthread_should_park()) { unsigned int to_submit; if (!list_empty(&ctx->iopoll_list)) { unsigned nr_events = 0; mutex_lock(&ctx->uring_lock); if (!list_empty(&ctx->iopoll_list) && !need_resched()) io_do_iopoll(ctx, &nr_events, 0); else timeout = jiffies + ctx->sq_thread_idle; mutex_unlock(&ctx->uring_lock); } to_submit = io_sqring_entries(ctx); /* * If submit got -EBUSY, flag us as needing the application * to enter the kernel to reap and flush events. */ if (!to_submit || ret == -EBUSY || need_resched()) { /* * Drop cur_mm before scheduling, we can't hold it for * long periods (or over schedule()). Do this before * adding ourselves to the waitqueue, as the unuse/drop * may sleep. */ io_sq_thread_drop_mm(); /* * We're polling. If we're within the defined idle * period, then let us spin without work before going * to sleep. The exception is if we got EBUSY doing * more IO, we should wait for the application to * reap events and wake us up. */ if (!list_empty(&ctx->iopoll_list) || need_resched() || (!time_after(jiffies, timeout) && ret != -EBUSY && !percpu_ref_is_dying(&ctx->refs))) { io_run_task_work(); cond_resched(); continue; } prepare_to_wait(&ctx->sqo_wait, &wait, TASK_INTERRUPTIBLE); /* * While doing polled IO, before going to sleep, we need * to check if there are new reqs added to iopoll_list, * it is because reqs may have been punted to io worker * and will be added to iopoll_list later, hence check * the iopoll_list again. */ if ((ctx->flags & IORING_SETUP_IOPOLL) && !list_empty_careful(&ctx->iopoll_list)) { finish_wait(&ctx->sqo_wait, &wait); continue; } io_ring_set_wakeup_flag(ctx); to_submit = io_sqring_entries(ctx); if (!to_submit || ret == -EBUSY) { if (kthread_should_park()) { finish_wait(&ctx->sqo_wait, &wait); break; } if (io_run_task_work()) { finish_wait(&ctx->sqo_wait, &wait); io_ring_clear_wakeup_flag(ctx); continue; } if (signal_pending(current)) flush_signals(current); schedule(); finish_wait(&ctx->sqo_wait, &wait); io_ring_clear_wakeup_flag(ctx); ret = 0; continue; } finish_wait(&ctx->sqo_wait, &wait); io_ring_clear_wakeup_flag(ctx); } mutex_lock(&ctx->uring_lock); if (likely(!percpu_ref_is_dying(&ctx->refs))) ret = io_submit_sqes(ctx, to_submit, NULL, -1); mutex_unlock(&ctx->uring_lock); timeout = jiffies + ctx->sq_thread_idle; } io_run_task_work(); io_sq_thread_drop_mm(); revert_creds(old_cred); kthread_parkme(); return 0; } struct io_wait_queue { struct wait_queue_entry wq; struct io_ring_ctx *ctx; unsigned to_wait; unsigned nr_timeouts; }; static inline bool io_should_wake(struct io_wait_queue *iowq, bool noflush) { struct io_ring_ctx *ctx = iowq->ctx; /* * Wake up if we have enough events, or if a timeout occurred since we * started waiting. For timeouts, we always want to return to userspace, * regardless of event count. */ return io_cqring_events(ctx, noflush) >= iowq->to_wait || atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts; } static int io_wake_function(struct wait_queue_entry *curr, unsigned int mode, int wake_flags, void *key) { struct io_wait_queue *iowq = container_of(curr, struct io_wait_queue, wq); /* use noflush == true, as we can't safely rely on locking context */ if (!io_should_wake(iowq, true)) return -1; return autoremove_wake_function(curr, mode, wake_flags, key); } /* * Wait until events become available, if we don't already have some. The * application must reap them itself, as they reside on the shared cq ring. */ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, const sigset_t __user *sig, size_t sigsz) { struct io_wait_queue iowq = { .wq = { .private = current, .func = io_wake_function, .entry = LIST_HEAD_INIT(iowq.wq.entry), }, .ctx = ctx, .to_wait = min_events, }; struct io_rings *rings = ctx->rings; int ret = 0; do { if (io_cqring_events(ctx, false) >= min_events) return 0; if (!io_run_task_work()) break; } while (1); if (sig) { #ifdef CONFIG_COMPAT if (in_compat_syscall()) ret = set_compat_user_sigmask((const compat_sigset_t __user *)sig, sigsz); else #endif ret = set_user_sigmask(sig, sigsz); if (ret) return ret; } iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts); trace_io_uring_cqring_wait(ctx, min_events); do { prepare_to_wait_exclusive(&ctx->wait, &iowq.wq, TASK_INTERRUPTIBLE); /* make sure we run task_work before checking for signals */ if (io_run_task_work()) continue; if (signal_pending(current)) { if (current->jobctl & JOBCTL_TASK_WORK) { spin_lock_irq(¤t->sighand->siglock); current->jobctl &= ~JOBCTL_TASK_WORK; recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); continue; } ret = -EINTR; break; } if (io_should_wake(&iowq, false)) break; schedule(); } while (1); finish_wait(&ctx->wait, &iowq.wq); restore_saved_sigmask_unless(ret == -EINTR); return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0; } static void __io_sqe_files_unregister(struct io_ring_ctx *ctx) { #if defined(CONFIG_UNIX) if (ctx->ring_sock) { struct sock *sock = ctx->ring_sock->sk; struct sk_buff *skb; while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL) kfree_skb(skb); } #else int i; for (i = 0; i < ctx->nr_user_files; i++) { struct file *file; file = io_file_from_index(ctx, i); if (file) fput(file); } #endif } static void io_file_ref_kill(struct percpu_ref *ref) { struct fixed_file_data *data; data = container_of(ref, struct fixed_file_data, refs); complete(&data->done); } static int io_sqe_files_unregister(struct io_ring_ctx *ctx) { struct fixed_file_data *data = ctx->file_data; struct fixed_file_ref_node *ref_node = NULL; unsigned nr_tables, i; if (!data) return -ENXIO; spin_lock(&data->lock); if (!list_empty(&data->ref_list)) ref_node = list_first_entry(&data->ref_list, struct fixed_file_ref_node, node); spin_unlock(&data->lock); if (ref_node) percpu_ref_kill(&ref_node->refs); percpu_ref_kill(&data->refs); /* wait for all refs nodes to complete */ flush_delayed_work(&ctx->file_put_work); wait_for_completion(&data->done); __io_sqe_files_unregister(ctx); nr_tables = DIV_ROUND_UP(ctx->nr_user_files, IORING_MAX_FILES_TABLE); for (i = 0; i < nr_tables; i++) kfree(data->table[i].files); kfree(data->table); percpu_ref_exit(&data->refs); kfree(data); ctx->file_data = NULL; ctx->nr_user_files = 0; return 0; } static void io_sq_thread_stop(struct io_ring_ctx *ctx) { if (ctx->sqo_thread) { wait_for_completion(&ctx->sq_thread_comp); /* * The park is a bit of a work-around, without it we get * warning spews on shutdown with SQPOLL set and affinity * set to a single CPU. */ kthread_park(ctx->sqo_thread); kthread_stop(ctx->sqo_thread); ctx->sqo_thread = NULL; } } static void io_finish_async(struct io_ring_ctx *ctx) { io_sq_thread_stop(ctx); if (ctx->io_wq) { io_wq_destroy(ctx->io_wq); ctx->io_wq = NULL; } } #if defined(CONFIG_UNIX) /* * Ensure the UNIX gc is aware of our file set, so we are certain that * the io_uring can be safely unregistered on process exit, even if we have * loops in the file referencing. */ static int __io_sqe_files_scm(struct io_ring_ctx *ctx, int nr, int offset) { struct sock *sk = ctx->ring_sock->sk; struct scm_fp_list *fpl; struct sk_buff *skb; int i, nr_files; fpl = kzalloc(sizeof(*fpl), GFP_KERNEL); if (!fpl) return -ENOMEM; skb = alloc_skb(0, GFP_KERNEL); if (!skb) { kfree(fpl); return -ENOMEM; } skb->sk = sk; nr_files = 0; fpl->user = get_uid(ctx->user); for (i = 0; i < nr; i++) { struct file *file = io_file_from_index(ctx, i + offset); if (!file) continue; fpl->fp[nr_files] = get_file(file); unix_inflight(fpl->user, fpl->fp[nr_files]); nr_files++; } if (nr_files) { fpl->max = SCM_MAX_FD; fpl->count = nr_files; UNIXCB(skb).fp = fpl; skb->destructor = unix_destruct_scm; refcount_add(skb->truesize, &sk->sk_wmem_alloc); skb_queue_head(&sk->sk_receive_queue, skb); for (i = 0; i < nr_files; i++) fput(fpl->fp[i]); } else { kfree_skb(skb); kfree(fpl); } return 0; } /* * If UNIX sockets are enabled, fd passing can cause a reference cycle which * causes regular reference counting to break down. We rely on the UNIX * garbage collection to take care of this problem for us. */ static int io_sqe_files_scm(struct io_ring_ctx *ctx) { unsigned left, total; int ret = 0; total = 0; left = ctx->nr_user_files; while (left) { unsigned this_files = min_t(unsigned, left, SCM_MAX_FD); ret = __io_sqe_files_scm(ctx, this_files, total); if (ret) break; left -= this_files; total += this_files; } if (!ret) return 0; while (total < ctx->nr_user_files) { struct file *file = io_file_from_index(ctx, total); if (file) fput(file); total++; } return ret; } #else static int io_sqe_files_scm(struct io_ring_ctx *ctx) { return 0; } #endif static int io_sqe_alloc_file_tables(struct io_ring_ctx *ctx, unsigned nr_tables, unsigned nr_files) { int i; for (i = 0; i < nr_tables; i++) { struct fixed_file_table *table = &ctx->file_data->table[i]; unsigned this_files; this_files = min(nr_files, IORING_MAX_FILES_TABLE); table->files = kcalloc(this_files, sizeof(struct file *), GFP_KERNEL); if (!table->files) break; nr_files -= this_files; } if (i == nr_tables) return 0; for (i = 0; i < nr_tables; i++) { struct fixed_file_table *table = &ctx->file_data->table[i]; kfree(table->files); } return 1; } static void io_ring_file_put(struct io_ring_ctx *ctx, struct file *file) { #if defined(CONFIG_UNIX) struct sock *sock = ctx->ring_sock->sk; struct sk_buff_head list, *head = &sock->sk_receive_queue; struct sk_buff *skb; int i; __skb_queue_head_init(&list); /* * Find the skb that holds this file in its SCM_RIGHTS. When found, * remove this entry and rearrange the file array. */ skb = skb_dequeue(head); while (skb) { struct scm_fp_list *fp; fp = UNIXCB(skb).fp; for (i = 0; i < fp->count; i++) { int left; if (fp->fp[i] != file) continue; unix_notinflight(fp->user, fp->fp[i]); left = fp->count - 1 - i; if (left) { memmove(&fp->fp[i], &fp->fp[i + 1], left * sizeof(struct file *)); } fp->count--; if (!fp->count) { kfree_skb(skb); skb = NULL; } else { __skb_queue_tail(&list, skb); } fput(file); file = NULL; break; } if (!file) break; __skb_queue_tail(&list, skb); skb = skb_dequeue(head); } if (skb_peek(&list)) { spin_lock_irq(&head->lock); while ((skb = __skb_dequeue(&list)) != NULL) __skb_queue_tail(head, skb); spin_unlock_irq(&head->lock); } #else fput(file); #endif } struct io_file_put { struct list_head list; struct file *file; }; static void __io_file_put_work(struct fixed_file_ref_node *ref_node) { struct fixed_file_data *file_data = ref_node->file_data; struct io_ring_ctx *ctx = file_data->ctx; struct io_file_put *pfile, *tmp; list_for_each_entry_safe(pfile, tmp, &ref_node->file_list, list) { list_del(&pfile->list); io_ring_file_put(ctx, pfile->file); kfree(pfile); } spin_lock(&file_data->lock); list_del(&ref_node->node); spin_unlock(&file_data->lock); percpu_ref_exit(&ref_node->refs); kfree(ref_node); percpu_ref_put(&file_data->refs); } static void io_file_put_work(struct work_struct *work) { struct io_ring_ctx *ctx; struct llist_node *node; ctx = container_of(work, struct io_ring_ctx, file_put_work.work); node = llist_del_all(&ctx->file_put_llist); while (node) { struct fixed_file_ref_node *ref_node; struct llist_node *next = node->next; ref_node = llist_entry(node, struct fixed_file_ref_node, llist); __io_file_put_work(ref_node); node = next; } } static void io_file_data_ref_zero(struct percpu_ref *ref) { struct fixed_file_ref_node *ref_node; struct io_ring_ctx *ctx; bool first_add; int delay = HZ; ref_node = container_of(ref, struct fixed_file_ref_node, refs); ctx = ref_node->file_data->ctx; if (percpu_ref_is_dying(&ctx->file_data->refs)) delay = 0; first_add = llist_add(&ref_node->llist, &ctx->file_put_llist); if (!delay) mod_delayed_work(system_wq, &ctx->file_put_work, 0); else if (first_add) queue_delayed_work(system_wq, &ctx->file_put_work, delay); } static struct fixed_file_ref_node *alloc_fixed_file_ref_node( struct io_ring_ctx *ctx) { struct fixed_file_ref_node *ref_node; ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL); if (!ref_node) return ERR_PTR(-ENOMEM); if (percpu_ref_init(&ref_node->refs, io_file_data_ref_zero, 0, GFP_KERNEL)) { kfree(ref_node); return ERR_PTR(-ENOMEM); } INIT_LIST_HEAD(&ref_node->node); INIT_LIST_HEAD(&ref_node->file_list); ref_node->file_data = ctx->file_data; return ref_node; } static void destroy_fixed_file_ref_node(struct fixed_file_ref_node *ref_node) { percpu_ref_exit(&ref_node->refs); kfree(ref_node); } static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, unsigned nr_args) { __s32 __user *fds = (__s32 __user *) arg; unsigned nr_tables; struct file *file; int fd, ret = 0; unsigned i; struct fixed_file_ref_node *ref_node; if (ctx->file_data) return -EBUSY; if (!nr_args) return -EINVAL; if (nr_args > IORING_MAX_FIXED_FILES) return -EMFILE; ctx->file_data = kzalloc(sizeof(*ctx->file_data), GFP_KERNEL); if (!ctx->file_data) return -ENOMEM; ctx->file_data->ctx = ctx; init_completion(&ctx->file_data->done); INIT_LIST_HEAD(&ctx->file_data->ref_list); spin_lock_init(&ctx->file_data->lock); nr_tables = DIV_ROUND_UP(nr_args, IORING_MAX_FILES_TABLE); ctx->file_data->table = kcalloc(nr_tables, sizeof(struct fixed_file_table), GFP_KERNEL); if (!ctx->file_data->table) { kfree(ctx->file_data); ctx->file_data = NULL; return -ENOMEM; } if (percpu_ref_init(&ctx->file_data->refs, io_file_ref_kill, PERCPU_REF_ALLOW_REINIT, GFP_KERNEL)) { kfree(ctx->file_data->table); kfree(ctx->file_data); ctx->file_data = NULL; return -ENOMEM; } if (io_sqe_alloc_file_tables(ctx, nr_tables, nr_args)) { percpu_ref_exit(&ctx->file_data->refs); kfree(ctx->file_data->table); kfree(ctx->file_data); ctx->file_data = NULL; return -ENOMEM; } for (i = 0; i < nr_args; i++, ctx->nr_user_files++) { struct fixed_file_table *table; unsigned index; ret = -EFAULT; if (copy_from_user(&fd, &fds[i], sizeof(fd))) break; /* allow sparse sets */ if (fd == -1) { ret = 0; continue; } table = &ctx->file_data->table[i >> IORING_FILE_TABLE_SHIFT]; index = i & IORING_FILE_TABLE_MASK; file = fget(fd); ret = -EBADF; if (!file) break; /* * Don't allow io_uring instances to be registered. If UNIX * isn't enabled, then this causes a reference cycle and this * instance can never get freed. If UNIX is enabled we'll * handle it just fine, but there's still no point in allowing * a ring fd as it doesn't support regular read/write anyway. */ if (file->f_op == &io_uring_fops) { fput(file); break; } ret = 0; table->files[index] = file; } if (ret) { for (i = 0; i < ctx->nr_user_files; i++) { file = io_file_from_index(ctx, i); if (file) fput(file); } for (i = 0; i < nr_tables; i++) kfree(ctx->file_data->table[i].files); percpu_ref_exit(&ctx->file_data->refs); kfree(ctx->file_data->table); kfree(ctx->file_data); ctx->file_data = NULL; ctx->nr_user_files = 0; return ret; } ret = io_sqe_files_scm(ctx); if (ret) { io_sqe_files_unregister(ctx); return ret; } ref_node = alloc_fixed_file_ref_node(ctx); if (IS_ERR(ref_node)) { io_sqe_files_unregister(ctx); return PTR_ERR(ref_node); } ctx->file_data->cur_refs = &ref_node->refs; spin_lock(&ctx->file_data->lock); list_add(&ref_node->node, &ctx->file_data->ref_list); spin_unlock(&ctx->file_data->lock); percpu_ref_get(&ctx->file_data->refs); return ret; } static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file, int index) { #if defined(CONFIG_UNIX) struct sock *sock = ctx->ring_sock->sk; struct sk_buff_head *head = &sock->sk_receive_queue; struct sk_buff *skb; /* * See if we can merge this file into an existing skb SCM_RIGHTS * file set. If there's no room, fall back to allocating a new skb * and filling it in. */ spin_lock_irq(&head->lock); skb = skb_peek(head); if (skb) { struct scm_fp_list *fpl = UNIXCB(skb).fp; if (fpl->count < SCM_MAX_FD) { __skb_unlink(skb, head); spin_unlock_irq(&head->lock); fpl->fp[fpl->count] = get_file(file); unix_inflight(fpl->user, fpl->fp[fpl->count]); fpl->count++; spin_lock_irq(&head->lock); __skb_queue_head(head, skb); } else { skb = NULL; } } spin_unlock_irq(&head->lock); if (skb) { fput(file); return 0; } return __io_sqe_files_scm(ctx, 1, index); #else return 0; #endif } static int io_queue_file_removal(struct fixed_file_data *data, struct file *file) { struct io_file_put *pfile; struct percpu_ref *refs = data->cur_refs; struct fixed_file_ref_node *ref_node; pfile = kzalloc(sizeof(*pfile), GFP_KERNEL); if (!pfile) return -ENOMEM; ref_node = container_of(refs, struct fixed_file_ref_node, refs); pfile->file = file; list_add(&pfile->list, &ref_node->file_list); return 0; } static int __io_sqe_files_update(struct io_ring_ctx *ctx, struct io_uring_files_update *up, unsigned nr_args) { struct fixed_file_data *data = ctx->file_data; struct fixed_file_ref_node *ref_node; struct file *file; __s32 __user *fds; int fd, i, err; __u32 done; bool needs_switch = false; if (check_add_overflow(up->offset, nr_args, &done)) return -EOVERFLOW; if (done > ctx->nr_user_files) return -EINVAL; ref_node = alloc_fixed_file_ref_node(ctx); if (IS_ERR(ref_node)) return PTR_ERR(ref_node); done = 0; fds = u64_to_user_ptr(up->fds); while (nr_args) { struct fixed_file_table *table; unsigned index; err = 0; if (copy_from_user(&fd, &fds[done], sizeof(fd))) { err = -EFAULT; break; } i = array_index_nospec(up->offset, ctx->nr_user_files); table = &ctx->file_data->table[i >> IORING_FILE_TABLE_SHIFT]; index = i & IORING_FILE_TABLE_MASK; if (table->files[index]) { file = table->files[index]; err = io_queue_file_removal(data, file); if (err) break; table->files[index] = NULL; needs_switch = true; } if (fd != -1) { file = fget(fd); if (!file) { err = -EBADF; break; } /* * Don't allow io_uring instances to be registered. If * UNIX isn't enabled, then this causes a reference * cycle and this instance can never get freed. If UNIX * is enabled we'll handle it just fine, but there's * still no point in allowing a ring fd as it doesn't * support regular read/write anyway. */ if (file->f_op == &io_uring_fops) { fput(file); err = -EBADF; break; } table->files[index] = file; err = io_sqe_file_register(ctx, file, i); if (err) { table->files[index] = NULL; fput(file); break; } } nr_args--; done++; up->offset++; } if (needs_switch) { percpu_ref_kill(data->cur_refs); spin_lock(&data->lock); list_add(&ref_node->node, &data->ref_list); data->cur_refs = &ref_node->refs; spin_unlock(&data->lock); percpu_ref_get(&ctx->file_data->refs); } else destroy_fixed_file_ref_node(ref_node); return done ? done : err; } static int io_sqe_files_update(struct io_ring_ctx *ctx, void __user *arg, unsigned nr_args) { struct io_uring_files_update up; if (!ctx->file_data) return -ENXIO; if (!nr_args) return -EINVAL; if (copy_from_user(&up, arg, sizeof(up))) return -EFAULT; if (up.resv) return -EINVAL; return __io_sqe_files_update(ctx, &up, nr_args); } static void io_free_work(struct io_wq_work *work) { struct io_kiocb *req = container_of(work, struct io_kiocb, work); /* Consider that io_steal_work() relies on this ref */ io_put_req(req); } static int io_init_wq_offload(struct io_ring_ctx *ctx, struct io_uring_params *p) { struct io_wq_data data; struct fd f; struct io_ring_ctx *ctx_attach; unsigned int concurrency; int ret = 0; data.user = ctx->user; data.free_work = io_free_work; data.do_work = io_wq_submit_work; if (!(p->flags & IORING_SETUP_ATTACH_WQ)) { /* Do QD, or 4 * CPUS, whatever is smallest */ concurrency = min(ctx->sq_entries, 4 * num_online_cpus()); ctx->io_wq = io_wq_create(concurrency, &data); if (IS_ERR(ctx->io_wq)) { ret = PTR_ERR(ctx->io_wq); ctx->io_wq = NULL; } return ret; } f = fdget(p->wq_fd); if (!f.file) return -EBADF; if (f.file->f_op != &io_uring_fops) { ret = -EINVAL; goto out_fput; } ctx_attach = f.file->private_data; /* @io_wq is protected by holding the fd */ if (!io_wq_get(ctx_attach->io_wq, &data)) { ret = -EINVAL; goto out_fput; } ctx->io_wq = ctx_attach->io_wq; out_fput: fdput(f); return ret; } static int io_sq_offload_start(struct io_ring_ctx *ctx, struct io_uring_params *p) { int ret; if (ctx->flags & IORING_SETUP_SQPOLL) { ret = -EPERM; if (!capable(CAP_SYS_ADMIN)) goto err; ctx->sq_thread_idle = msecs_to_jiffies(p->sq_thread_idle); if (!ctx->sq_thread_idle) ctx->sq_thread_idle = HZ; if (p->flags & IORING_SETUP_SQ_AFF) { int cpu = p->sq_thread_cpu; ret = -EINVAL; if (cpu >= nr_cpu_ids) goto err; if (!cpu_online(cpu)) goto err; ctx->sqo_thread = kthread_create_on_cpu(io_sq_thread, ctx, cpu, "io_uring-sq"); } else { ctx->sqo_thread = kthread_create(io_sq_thread, ctx, "io_uring-sq"); } if (IS_ERR(ctx->sqo_thread)) { ret = PTR_ERR(ctx->sqo_thread); ctx->sqo_thread = NULL; goto err; } wake_up_process(ctx->sqo_thread); } else if (p->flags & IORING_SETUP_SQ_AFF) { /* Can't have SQ_AFF without SQPOLL */ ret = -EINVAL; goto err; } ret = io_init_wq_offload(ctx, p); if (ret) goto err; return 0; err: io_finish_async(ctx); return ret; } static inline void __io_unaccount_mem(struct user_struct *user, unsigned long nr_pages) { atomic_long_sub(nr_pages, &user->locked_vm); } static inline int __io_account_mem(struct user_struct *user, unsigned long nr_pages) { unsigned long page_limit, cur_pages, new_pages; /* Don't allow more pages than we can safely lock */ page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; do { cur_pages = atomic_long_read(&user->locked_vm); new_pages = cur_pages + nr_pages; if (new_pages > page_limit) return -ENOMEM; } while (atomic_long_cmpxchg(&user->locked_vm, cur_pages, new_pages) != cur_pages); return 0; } static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages, enum io_mem_account acct) { if (ctx->limit_mem) __io_unaccount_mem(ctx->user, nr_pages); if (ctx->sqo_mm) { if (acct == ACCT_LOCKED) ctx->sqo_mm->locked_vm -= nr_pages; else if (acct == ACCT_PINNED) atomic64_sub(nr_pages, &ctx->sqo_mm->pinned_vm); } } static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages, enum io_mem_account acct) { int ret; if (ctx->limit_mem) { ret = __io_account_mem(ctx->user, nr_pages); if (ret) return ret; } if (ctx->sqo_mm) { if (acct == ACCT_LOCKED) ctx->sqo_mm->locked_vm += nr_pages; else if (acct == ACCT_PINNED) atomic64_add(nr_pages, &ctx->sqo_mm->pinned_vm); } return 0; } static void io_mem_free(void *ptr) { struct page *page; if (!ptr) return; page = virt_to_head_page(ptr); if (put_page_testzero(page)) free_compound_page(page); } static void *io_mem_alloc(size_t size) { gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP | __GFP_NORETRY; return (void *) __get_free_pages(gfp_flags, get_order(size)); } static unsigned long rings_size(unsigned sq_entries, unsigned cq_entries, size_t *sq_offset) { struct io_rings *rings; size_t off, sq_array_size; off = struct_size(rings, cqes, cq_entries); if (off == SIZE_MAX) return SIZE_MAX; #ifdef CONFIG_SMP off = ALIGN(off, SMP_CACHE_BYTES); if (off == 0) return SIZE_MAX; #endif if (sq_offset) *sq_offset = off; sq_array_size = array_size(sizeof(u32), sq_entries); if (sq_array_size == SIZE_MAX) return SIZE_MAX; if (check_add_overflow(off, sq_array_size, &off)) return SIZE_MAX; return off; } static unsigned long ring_pages(unsigned sq_entries, unsigned cq_entries) { size_t pages; pages = (size_t)1 << get_order( rings_size(sq_entries, cq_entries, NULL)); pages += (size_t)1 << get_order( array_size(sizeof(struct io_uring_sqe), sq_entries)); return pages; } static int io_sqe_buffer_unregister(struct io_ring_ctx *ctx) { int i, j; if (!ctx->user_bufs) return -ENXIO; for (i = 0; i < ctx->nr_user_bufs; i++) { struct io_mapped_ubuf *imu = &ctx->user_bufs[i]; for (j = 0; j < imu->nr_bvecs; j++) unpin_user_page(imu->bvec[j].bv_page); io_unaccount_mem(ctx, imu->nr_bvecs, ACCT_PINNED); kvfree(imu->bvec); imu->nr_bvecs = 0; } kfree(ctx->user_bufs); ctx->user_bufs = NULL; ctx->nr_user_bufs = 0; return 0; } static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst, void __user *arg, unsigned index) { struct iovec __user *src; #ifdef CONFIG_COMPAT if (ctx->compat) { struct compat_iovec __user *ciovs; struct compat_iovec ciov; ciovs = (struct compat_iovec __user *) arg; if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov))) return -EFAULT; dst->iov_base = u64_to_user_ptr((u64)ciov.iov_base); dst->iov_len = ciov.iov_len; return 0; } #endif src = (struct iovec __user *) arg; if (copy_from_user(dst, &src[index], sizeof(*dst))) return -EFAULT; return 0; } static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg, unsigned nr_args) { struct vm_area_struct **vmas = NULL; struct page **pages = NULL; int i, j, got_pages = 0; int ret = -EINVAL; if (ctx->user_bufs) return -EBUSY; if (!nr_args || nr_args > UIO_MAXIOV) return -EINVAL; ctx->user_bufs = kcalloc(nr_args, sizeof(struct io_mapped_ubuf), GFP_KERNEL); if (!ctx->user_bufs) return -ENOMEM; for (i = 0; i < nr_args; i++) { struct io_mapped_ubuf *imu = &ctx->user_bufs[i]; unsigned long off, start, end, ubuf; int pret, nr_pages; struct iovec iov; size_t size; ret = io_copy_iov(ctx, &iov, arg, i); if (ret) goto err; /* * Don't impose further limits on the size and buffer * constraints here, we'll -EINVAL later when IO is * submitted if they are wrong. */ ret = -EFAULT; if (!iov.iov_base || !iov.iov_len) goto err; /* arbitrary limit, but we need something */ if (iov.iov_len > SZ_1G) goto err; ubuf = (unsigned long) iov.iov_base; end = (ubuf + iov.iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT; start = ubuf >> PAGE_SHIFT; nr_pages = end - start; ret = io_account_mem(ctx, nr_pages, ACCT_PINNED); if (ret) goto err; ret = 0; if (!pages || nr_pages > got_pages) { kvfree(vmas); kvfree(pages); pages = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL); vmas = kvmalloc_array(nr_pages, sizeof(struct vm_area_struct *), GFP_KERNEL); if (!pages || !vmas) { ret = -ENOMEM; io_unaccount_mem(ctx, nr_pages, ACCT_PINNED); goto err; } got_pages = nr_pages; } imu->bvec = kvmalloc_array(nr_pages, sizeof(struct bio_vec), GFP_KERNEL); ret = -ENOMEM; if (!imu->bvec) { io_unaccount_mem(ctx, nr_pages, ACCT_PINNED); goto err; } ret = 0; mmap_read_lock(current->mm); pret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM, pages, vmas); if (pret == nr_pages) { /* don't support file backed memory */ for (j = 0; j < nr_pages; j++) { struct vm_area_struct *vma = vmas[j]; if (vma->vm_file && !is_file_hugepages(vma->vm_file)) { ret = -EOPNOTSUPP; break; } } } else { ret = pret < 0 ? pret : -EFAULT; } mmap_read_unlock(current->mm); if (ret) { /* * if we did partial map, or found file backed vmas, * release any pages we did get */ if (pret > 0) unpin_user_pages(pages, pret); io_unaccount_mem(ctx, nr_pages, ACCT_PINNED); kvfree(imu->bvec); goto err; } off = ubuf & ~PAGE_MASK; size = iov.iov_len; for (j = 0; j < nr_pages; j++) { size_t vec_len; vec_len = min_t(size_t, size, PAGE_SIZE - off); imu->bvec[j].bv_page = pages[j]; imu->bvec[j].bv_len = vec_len; imu->bvec[j].bv_offset = off; off = 0; size -= vec_len; } /* store original address for later verification */ imu->ubuf = ubuf; imu->len = iov.iov_len; imu->nr_bvecs = nr_pages; ctx->nr_user_bufs++; } kvfree(pages); kvfree(vmas); return 0; err: kvfree(pages); kvfree(vmas); io_sqe_buffer_unregister(ctx); return ret; } static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg) { __s32 __user *fds = arg; int fd; if (ctx->cq_ev_fd) return -EBUSY; if (copy_from_user(&fd, fds, sizeof(*fds))) return -EFAULT; ctx->cq_ev_fd = eventfd_ctx_fdget(fd); if (IS_ERR(ctx->cq_ev_fd)) { int ret = PTR_ERR(ctx->cq_ev_fd); ctx->cq_ev_fd = NULL; return ret; } return 0; } static int io_eventfd_unregister(struct io_ring_ctx *ctx) { if (ctx->cq_ev_fd) { eventfd_ctx_put(ctx->cq_ev_fd); ctx->cq_ev_fd = NULL; return 0; } return -ENXIO; } static int __io_destroy_buffers(int id, void *p, void *data) { struct io_ring_ctx *ctx = data; struct io_buffer *buf = p; __io_remove_buffers(ctx, buf, id, -1U); return 0; } static void io_destroy_buffers(struct io_ring_ctx *ctx) { idr_for_each(&ctx->io_buffer_idr, __io_destroy_buffers, ctx); idr_destroy(&ctx->io_buffer_idr); } static void io_ring_ctx_free(struct io_ring_ctx *ctx) { io_finish_async(ctx); io_sqe_buffer_unregister(ctx); if (ctx->sqo_mm) { mmdrop(ctx->sqo_mm); ctx->sqo_mm = NULL; } io_sqe_files_unregister(ctx); io_eventfd_unregister(ctx); io_destroy_buffers(ctx); idr_destroy(&ctx->personality_idr); #if defined(CONFIG_UNIX) if (ctx->ring_sock) { ctx->ring_sock->file = NULL; /* so that iput() is called */ sock_release(ctx->ring_sock); } #endif io_mem_free(ctx->rings); io_mem_free(ctx->sq_sqes); percpu_ref_exit(&ctx->refs); free_uid(ctx->user); put_cred(ctx->creds); kfree(ctx->cancel_hash); kmem_cache_free(req_cachep, ctx->fallback_req); kfree(ctx); } static __poll_t io_uring_poll(struct file *file, poll_table *wait) { struct io_ring_ctx *ctx = file->private_data; __poll_t mask = 0; poll_wait(file, &ctx->cq_wait, wait); /* * synchronizes with barrier from wq_has_sleeper call in * io_commit_cqring */ smp_rmb(); if (READ_ONCE(ctx->rings->sq.tail) - ctx->cached_sq_head != ctx->rings->sq_ring_entries) mask |= EPOLLOUT | EPOLLWRNORM; if (io_cqring_events(ctx, false)) mask |= EPOLLIN | EPOLLRDNORM; return mask; } static int io_uring_fasync(int fd, struct file *file, int on) { struct io_ring_ctx *ctx = file->private_data; return fasync_helper(fd, file, on, &ctx->cq_fasync); } static int io_remove_personalities(int id, void *p, void *data) { struct io_ring_ctx *ctx = data; const struct cred *cred; cred = idr_remove(&ctx->personality_idr, id); if (cred) put_cred(cred); return 0; } static void io_ring_exit_work(struct work_struct *work) { struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx, exit_work); /* * If we're doing polled IO and end up having requests being * submitted async (out-of-line), then completions can come in while * we're waiting for refs to drop. We need to reap these manually, * as nobody else will be looking for them. */ do { if (ctx->rings) io_cqring_overflow_flush(ctx, true); io_iopoll_try_reap_events(ctx); } while (!wait_for_completion_timeout(&ctx->ref_comp, HZ/20)); io_ring_ctx_free(ctx); } static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx) { mutex_lock(&ctx->uring_lock); percpu_ref_kill(&ctx->refs); mutex_unlock(&ctx->uring_lock); io_kill_timeouts(ctx); io_poll_remove_all(ctx); if (ctx->io_wq) io_wq_cancel_all(ctx->io_wq); /* if we failed setting up the ctx, we might not have any rings */ if (ctx->rings) io_cqring_overflow_flush(ctx, true); io_iopoll_try_reap_events(ctx); idr_for_each(&ctx->personality_idr, io_remove_personalities, ctx); /* * Do this upfront, so we won't have a grace period where the ring * is closed but resources aren't reaped yet. This can cause * spurious failure in setting up a new ring. */ io_unaccount_mem(ctx, ring_pages(ctx->sq_entries, ctx->cq_entries), ACCT_LOCKED); INIT_WORK(&ctx->exit_work, io_ring_exit_work); /* * Use system_unbound_wq to avoid spawning tons of event kworkers * if we're exiting a ton of rings at the same time. It just adds * noise and overhead, there's no discernable change in runtime * over using system_wq. */ queue_work(system_unbound_wq, &ctx->exit_work); } static int io_uring_release(struct inode *inode, struct file *file) { struct io_ring_ctx *ctx = file->private_data; file->private_data = NULL; io_ring_ctx_wait_and_kill(ctx); return 0; } static bool io_wq_files_match(struct io_wq_work *work, void *data) { struct files_struct *files = data; return work->files == files; } /* * Returns true if 'preq' is the link parent of 'req' */ static bool io_match_link(struct io_kiocb *preq, struct io_kiocb *req) { struct io_kiocb *link; if (!(preq->flags & REQ_F_LINK_HEAD)) return false; list_for_each_entry(link, &preq->link_list, link_list) { if (link == req) return true; } return false; } static inline bool io_match_files(struct io_kiocb *req, struct files_struct *files) { return (req->flags & REQ_F_WORK_INITIALIZED) && req->work.files == files; } static bool io_match_link_files(struct io_kiocb *req, struct files_struct *files) { struct io_kiocb *link; if (io_match_files(req, files)) return true; if (req->flags & REQ_F_LINK_HEAD) { list_for_each_entry(link, &req->link_list, link_list) { if (io_match_files(link, files)) return true; } } return false; } /* * We're looking to cancel 'req' because it's holding on to our files, but * 'req' could be a link to another request. See if it is, and cancel that * parent request if so. */ static bool io_poll_remove_link(struct io_ring_ctx *ctx, struct io_kiocb *req) { struct hlist_node *tmp; struct io_kiocb *preq; bool found = false; int i; spin_lock_irq(&ctx->completion_lock); for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) { struct hlist_head *list; list = &ctx->cancel_hash[i]; hlist_for_each_entry_safe(preq, tmp, list, hash_node) { found = io_match_link(preq, req); if (found) { io_poll_remove_one(preq); break; } } } spin_unlock_irq(&ctx->completion_lock); return found; } static bool io_timeout_remove_link(struct io_ring_ctx *ctx, struct io_kiocb *req) { struct io_kiocb *preq; bool found = false; spin_lock_irq(&ctx->completion_lock); list_for_each_entry(preq, &ctx->timeout_list, timeout.list) { found = io_match_link(preq, req); if (found) { __io_timeout_cancel(preq); break; } } spin_unlock_irq(&ctx->completion_lock); return found; } static bool io_cancel_link_cb(struct io_wq_work *work, void *data) { return io_match_link(container_of(work, struct io_kiocb, work), data); } static void io_attempt_cancel(struct io_ring_ctx *ctx, struct io_kiocb *req) { enum io_wq_cancel cret; /* cancel this particular work, if it's running */ cret = io_wq_cancel_work(ctx->io_wq, &req->work); if (cret != IO_WQ_CANCEL_NOTFOUND) return; /* find links that hold this pending, cancel those */ cret = io_wq_cancel_cb(ctx->io_wq, io_cancel_link_cb, req, true); if (cret != IO_WQ_CANCEL_NOTFOUND) return; /* if we have a poll link holding this pending, cancel that */ if (io_poll_remove_link(ctx, req)) return; /* final option, timeout link is holding this req pending */ io_timeout_remove_link(ctx, req); } static void io_cancel_defer_files(struct io_ring_ctx *ctx, struct files_struct *files) { struct io_defer_entry *de = NULL; LIST_HEAD(list); spin_lock_irq(&ctx->completion_lock); list_for_each_entry_reverse(de, &ctx->defer_list, list) { if (io_match_link_files(de->req, files)) { list_cut_position(&list, &ctx->defer_list, &de->list); break; } } spin_unlock_irq(&ctx->completion_lock); while (!list_empty(&list)) { de = list_first_entry(&list, struct io_defer_entry, list); list_del_init(&de->list); req_set_fail_links(de->req); io_put_req(de->req); io_req_complete(de->req, -ECANCELED); kfree(de); } } static void io_uring_cancel_files(struct io_ring_ctx *ctx, struct files_struct *files) { if (list_empty_careful(&ctx->inflight_list)) return; io_cancel_defer_files(ctx, files); /* cancel all at once, should be faster than doing it one by one*/ io_wq_cancel_cb(ctx->io_wq, io_wq_files_match, files, true); while (!list_empty_careful(&ctx->inflight_list)) { struct io_kiocb *cancel_req = NULL, *req; DEFINE_WAIT(wait); spin_lock_irq(&ctx->inflight_lock); list_for_each_entry(req, &ctx->inflight_list, inflight_entry) { if (req->work.files != files) continue; /* req is being completed, ignore */ if (!refcount_inc_not_zero(&req->refs)) continue; cancel_req = req; break; } if (cancel_req) prepare_to_wait(&ctx->inflight_wait, &wait, TASK_UNINTERRUPTIBLE); spin_unlock_irq(&ctx->inflight_lock); /* We need to keep going until we don't find a matching req */ if (!cancel_req) break; /* cancel this request, or head link requests */ io_attempt_cancel(ctx, cancel_req); io_put_req(cancel_req); /* cancellations _may_ trigger task work */ io_run_task_work(); schedule(); finish_wait(&ctx->inflight_wait, &wait); } } static bool io_cancel_task_cb(struct io_wq_work *work, void *data) { struct io_kiocb *req = container_of(work, struct io_kiocb, work); struct task_struct *task = data; return req->task == task; } static int io_uring_flush(struct file *file, void *data) { struct io_ring_ctx *ctx = file->private_data; io_uring_cancel_files(ctx, data); /* * If the task is going away, cancel work it may have pending */ if (fatal_signal_pending(current) || (current->flags & PF_EXITING)) io_wq_cancel_cb(ctx->io_wq, io_cancel_task_cb, current, true); return 0; } static void *io_uring_validate_mmap_request(struct file *file, loff_t pgoff, size_t sz) { struct io_ring_ctx *ctx = file->private_data; loff_t offset = pgoff << PAGE_SHIFT; struct page *page; void *ptr; switch (offset) { case IORING_OFF_SQ_RING: case IORING_OFF_CQ_RING: ptr = ctx->rings; break; case IORING_OFF_SQES: ptr = ctx->sq_sqes; break; default: return ERR_PTR(-EINVAL); } page = virt_to_head_page(ptr); if (sz > page_size(page)) return ERR_PTR(-EINVAL); return ptr; } #ifdef CONFIG_MMU static int io_uring_mmap(struct file *file, struct vm_area_struct *vma) { size_t sz = vma->vm_end - vma->vm_start; unsigned long pfn; void *ptr; ptr = io_uring_validate_mmap_request(file, vma->vm_pgoff, sz); if (IS_ERR(ptr)) return PTR_ERR(ptr); pfn = virt_to_phys(ptr) >> PAGE_SHIFT; return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot); } #else /* !CONFIG_MMU */ static int io_uring_mmap(struct file *file, struct vm_area_struct *vma) { return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -EINVAL; } static unsigned int io_uring_nommu_mmap_capabilities(struct file *file) { return NOMMU_MAP_DIRECT | NOMMU_MAP_READ | NOMMU_MAP_WRITE; } static unsigned long io_uring_nommu_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { void *ptr; ptr = io_uring_validate_mmap_request(file, pgoff, len); if (IS_ERR(ptr)) return PTR_ERR(ptr); return (unsigned long) ptr; } #endif /* !CONFIG_MMU */ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, u32, min_complete, u32, flags, const sigset_t __user *, sig, size_t, sigsz) { struct io_ring_ctx *ctx; long ret = -EBADF; int submitted = 0; struct fd f; io_run_task_work(); if (flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP)) return -EINVAL; f = fdget(fd); if (!f.file) return -EBADF; ret = -EOPNOTSUPP; if (f.file->f_op != &io_uring_fops) goto out_fput; ret = -ENXIO; ctx = f.file->private_data; if (!percpu_ref_tryget(&ctx->refs)) goto out_fput; /* * For SQ polling, the thread will do all submissions and completions. * Just return the requested submit count, and wake the thread if * we were asked to. */ ret = 0; if (ctx->flags & IORING_SETUP_SQPOLL) { if (!list_empty_careful(&ctx->cq_overflow_list)) io_cqring_overflow_flush(ctx, false); if (flags & IORING_ENTER_SQ_WAKEUP) wake_up(&ctx->sqo_wait); submitted = to_submit; } else if (to_submit) { mutex_lock(&ctx->uring_lock); submitted = io_submit_sqes(ctx, to_submit, f.file, fd); mutex_unlock(&ctx->uring_lock); if (submitted != to_submit) goto out; } if (flags & IORING_ENTER_GETEVENTS) { min_complete = min(min_complete, ctx->cq_entries); /* * When SETUP_IOPOLL and SETUP_SQPOLL are both enabled, user * space applications don't need to do io completion events * polling again, they can rely on io_sq_thread to do polling * work, which can reduce cpu usage and uring_lock contention. */ if (ctx->flags & IORING_SETUP_IOPOLL && !(ctx->flags & IORING_SETUP_SQPOLL)) { ret = io_iopoll_check(ctx, min_complete); } else { ret = io_cqring_wait(ctx, min_complete, sig, sigsz); } } out: percpu_ref_put(&ctx->refs); out_fput: fdput(f); return submitted ? submitted : ret; } #ifdef CONFIG_PROC_FS static int io_uring_show_cred(int id, void *p, void *data) { const struct cred *cred = p; struct seq_file *m = data; struct user_namespace *uns = seq_user_ns(m); struct group_info *gi; kernel_cap_t cap; unsigned __capi; int g; seq_printf(m, "%5d\n", id); seq_put_decimal_ull(m, "\tUid:\t", from_kuid_munged(uns, cred->uid)); seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->euid)); seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->suid)); seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->fsuid)); seq_put_decimal_ull(m, "\n\tGid:\t", from_kgid_munged(uns, cred->gid)); seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->egid)); seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->sgid)); seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->fsgid)); seq_puts(m, "\n\tGroups:\t"); gi = cred->group_info; for (g = 0; g < gi->ngroups; g++) { seq_put_decimal_ull(m, g ? " " : "", from_kgid_munged(uns, gi->gid[g])); } seq_puts(m, "\n\tCapEff:\t"); cap = cred->cap_effective; CAP_FOR_EACH_U32(__capi) seq_put_hex_ll(m, NULL, cap.cap[CAP_LAST_U32 - __capi], 8); seq_putc(m, '\n'); return 0; } static void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, struct seq_file *m) { bool has_lock; int i; /* * Avoid ABBA deadlock between the seq lock and the io_uring mutex, * since fdinfo case grabs it in the opposite direction of normal use * cases. If we fail to get the lock, we just don't iterate any * structures that could be going away outside the io_uring mutex. */ has_lock = mutex_trylock(&ctx->uring_lock); seq_printf(m, "UserFiles:\t%u\n", ctx->nr_user_files); for (i = 0; has_lock && i < ctx->nr_user_files; i++) { struct fixed_file_table *table; struct file *f; table = &ctx->file_data->table[i >> IORING_FILE_TABLE_SHIFT]; f = table->files[i & IORING_FILE_TABLE_MASK]; if (f) seq_printf(m, "%5u: %s\n", i, file_dentry(f)->d_iname); else seq_printf(m, "%5u: \n", i); } seq_printf(m, "UserBufs:\t%u\n", ctx->nr_user_bufs); for (i = 0; has_lock && i < ctx->nr_user_bufs; i++) { struct io_mapped_ubuf *buf = &ctx->user_bufs[i]; seq_printf(m, "%5u: 0x%llx/%u\n", i, buf->ubuf, (unsigned int) buf->len); } if (has_lock && !idr_is_empty(&ctx->personality_idr)) { seq_printf(m, "Personalities:\n"); idr_for_each(&ctx->personality_idr, io_uring_show_cred, m); } seq_printf(m, "PollList:\n"); spin_lock_irq(&ctx->completion_lock); for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) { struct hlist_head *list = &ctx->cancel_hash[i]; struct io_kiocb *req; hlist_for_each_entry(req, list, hash_node) seq_printf(m, " op=%d, task_works=%d\n", req->opcode, req->task->task_works != NULL); } spin_unlock_irq(&ctx->completion_lock); if (has_lock) mutex_unlock(&ctx->uring_lock); } static void io_uring_show_fdinfo(struct seq_file *m, struct file *f) { struct io_ring_ctx *ctx = f->private_data; if (percpu_ref_tryget(&ctx->refs)) { __io_uring_show_fdinfo(ctx, m); percpu_ref_put(&ctx->refs); } } #endif static const struct file_operations io_uring_fops = { .release = io_uring_release, .flush = io_uring_flush, .mmap = io_uring_mmap, #ifndef CONFIG_MMU .get_unmapped_area = io_uring_nommu_get_unmapped_area, .mmap_capabilities = io_uring_nommu_mmap_capabilities, #endif .poll = io_uring_poll, .fasync = io_uring_fasync, #ifdef CONFIG_PROC_FS .show_fdinfo = io_uring_show_fdinfo, #endif }; static int io_allocate_scq_urings(struct io_ring_ctx *ctx, struct io_uring_params *p) { struct io_rings *rings; size_t size, sq_array_offset; /* make sure these are sane, as we already accounted them */ ctx->sq_entries = p->sq_entries; ctx->cq_entries = p->cq_entries; size = rings_size(p->sq_entries, p->cq_entries, &sq_array_offset); if (size == SIZE_MAX) return -EOVERFLOW; rings = io_mem_alloc(size); if (!rings) return -ENOMEM; ctx->rings = rings; ctx->sq_array = (u32 *)((char *)rings + sq_array_offset); rings->sq_ring_mask = p->sq_entries - 1; rings->cq_ring_mask = p->cq_entries - 1; rings->sq_ring_entries = p->sq_entries; rings->cq_ring_entries = p->cq_entries; ctx->sq_mask = rings->sq_ring_mask; ctx->cq_mask = rings->cq_ring_mask; size = array_size(sizeof(struct io_uring_sqe), p->sq_entries); if (size == SIZE_MAX) { io_mem_free(ctx->rings); ctx->rings = NULL; return -EOVERFLOW; } ctx->sq_sqes = io_mem_alloc(size); if (!ctx->sq_sqes) { io_mem_free(ctx->rings); ctx->rings = NULL; return -ENOMEM; } return 0; } /* * Allocate an anonymous fd, this is what constitutes the application * visible backing of an io_uring instance. The application mmaps this * fd to gain access to the SQ/CQ ring details. If UNIX sockets are enabled, * we have to tie this fd to a socket for file garbage collection purposes. */ static int io_uring_get_fd(struct io_ring_ctx *ctx) { struct file *file; int ret; #if defined(CONFIG_UNIX) ret = sock_create_kern(&init_net, PF_UNIX, SOCK_RAW, IPPROTO_IP, &ctx->ring_sock); if (ret) return ret; #endif ret = get_unused_fd_flags(O_RDWR | O_CLOEXEC); if (ret < 0) goto err; file = anon_inode_getfile("[io_uring]", &io_uring_fops, ctx, O_RDWR | O_CLOEXEC); if (IS_ERR(file)) { put_unused_fd(ret); ret = PTR_ERR(file); goto err; } #if defined(CONFIG_UNIX) ctx->ring_sock->file = file; #endif fd_install(ret, file); return ret; err: #if defined(CONFIG_UNIX) sock_release(ctx->ring_sock); ctx->ring_sock = NULL; #endif return ret; } static int io_uring_create(unsigned entries, struct io_uring_params *p, struct io_uring_params __user *params) { struct user_struct *user = NULL; struct io_ring_ctx *ctx; bool limit_mem; int ret; if (!entries) return -EINVAL; if (entries > IORING_MAX_ENTRIES) { if (!(p->flags & IORING_SETUP_CLAMP)) return -EINVAL; entries = IORING_MAX_ENTRIES; } /* * Use twice as many entries for the CQ ring. It's possible for the * application to drive a higher depth than the size of the SQ ring, * since the sqes are only used at submission time. This allows for * some flexibility in overcommitting a bit. If the application has * set IORING_SETUP_CQSIZE, it will have passed in the desired number * of CQ ring entries manually. */ p->sq_entries = roundup_pow_of_two(entries); if (p->flags & IORING_SETUP_CQSIZE) { /* * If IORING_SETUP_CQSIZE is set, we do the same roundup * to a power-of-two, if it isn't already. We do NOT impose * any cq vs sq ring sizing. */ if (p->cq_entries < p->sq_entries) return -EINVAL; if (p->cq_entries > IORING_MAX_CQ_ENTRIES) { if (!(p->flags & IORING_SETUP_CLAMP)) return -EINVAL; p->cq_entries = IORING_MAX_CQ_ENTRIES; } p->cq_entries = roundup_pow_of_two(p->cq_entries); } else { p->cq_entries = 2 * p->sq_entries; } user = get_uid(current_user()); limit_mem = !capable(CAP_IPC_LOCK); if (limit_mem) { ret = __io_account_mem(user, ring_pages(p->sq_entries, p->cq_entries)); if (ret) { free_uid(user); return ret; } } ctx = io_ring_ctx_alloc(p); if (!ctx) { if (limit_mem) __io_unaccount_mem(user, ring_pages(p->sq_entries, p->cq_entries)); free_uid(user); return -ENOMEM; } ctx->compat = in_compat_syscall(); ctx->user = user; ctx->creds = get_current_cred(); mmgrab(current->mm); ctx->sqo_mm = current->mm; /* * Account memory _before_ installing the file descriptor. Once * the descriptor is installed, it can get closed at any time. Also * do this before hitting the general error path, as ring freeing * will un-account as well. */ io_account_mem(ctx, ring_pages(p->sq_entries, p->cq_entries), ACCT_LOCKED); ctx->limit_mem = limit_mem; ret = io_allocate_scq_urings(ctx, p); if (ret) goto err; ret = io_sq_offload_start(ctx, p); if (ret) goto err; memset(&p->sq_off, 0, sizeof(p->sq_off)); p->sq_off.head = offsetof(struct io_rings, sq.head); p->sq_off.tail = offsetof(struct io_rings, sq.tail); p->sq_off.ring_mask = offsetof(struct io_rings, sq_ring_mask); p->sq_off.ring_entries = offsetof(struct io_rings, sq_ring_entries); p->sq_off.flags = offsetof(struct io_rings, sq_flags); p->sq_off.dropped = offsetof(struct io_rings, sq_dropped); p->sq_off.array = (char *)ctx->sq_array - (char *)ctx->rings; memset(&p->cq_off, 0, sizeof(p->cq_off)); p->cq_off.head = offsetof(struct io_rings, cq.head); p->cq_off.tail = offsetof(struct io_rings, cq.tail); p->cq_off.ring_mask = offsetof(struct io_rings, cq_ring_mask); p->cq_off.ring_entries = offsetof(struct io_rings, cq_ring_entries); p->cq_off.overflow = offsetof(struct io_rings, cq_overflow); p->cq_off.cqes = offsetof(struct io_rings, cqes); p->cq_off.flags = offsetof(struct io_rings, cq_flags); p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP | IORING_FEAT_SUBMIT_STABLE | IORING_FEAT_RW_CUR_POS | IORING_FEAT_CUR_PERSONALITY | IORING_FEAT_FAST_POLL | IORING_FEAT_POLL_32BITS; if (copy_to_user(params, p, sizeof(*p))) { ret = -EFAULT; goto err; } /* * Install ring fd as the very last thing, so we don't risk someone * having closed it before we finish setup */ ret = io_uring_get_fd(ctx); if (ret < 0) goto err; trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags); return ret; err: io_ring_ctx_wait_and_kill(ctx); return ret; } /* * Sets up an aio uring context, and returns the fd. Applications asks for a * ring size, we return the actual sq/cq ring sizes (among other things) in the * params structure passed in. */ static long io_uring_setup(u32 entries, struct io_uring_params __user *params) { struct io_uring_params p; int i; if (copy_from_user(&p, params, sizeof(p))) return -EFAULT; for (i = 0; i < ARRAY_SIZE(p.resv); i++) { if (p.resv[i]) return -EINVAL; } if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL | IORING_SETUP_SQ_AFF | IORING_SETUP_CQSIZE | IORING_SETUP_CLAMP | IORING_SETUP_ATTACH_WQ)) return -EINVAL; return io_uring_create(entries, &p, params); } SYSCALL_DEFINE2(io_uring_setup, u32, entries, struct io_uring_params __user *, params) { return io_uring_setup(entries, params); } static int io_probe(struct io_ring_ctx *ctx, void __user *arg, unsigned nr_args) { struct io_uring_probe *p; size_t size; int i, ret; size = struct_size(p, ops, nr_args); if (size == SIZE_MAX) return -EOVERFLOW; p = kzalloc(size, GFP_KERNEL); if (!p) return -ENOMEM; ret = -EFAULT; if (copy_from_user(p, arg, size)) goto out; ret = -EINVAL; if (memchr_inv(p, 0, size)) goto out; p->last_op = IORING_OP_LAST - 1; if (nr_args > IORING_OP_LAST) nr_args = IORING_OP_LAST; for (i = 0; i < nr_args; i++) { p->ops[i].op = i; if (!io_op_defs[i].not_supported) p->ops[i].flags = IO_URING_OP_SUPPORTED; } p->ops_len = i; ret = 0; if (copy_to_user(arg, p, size)) ret = -EFAULT; out: kfree(p); return ret; } static int io_register_personality(struct io_ring_ctx *ctx) { const struct cred *creds = get_current_cred(); int id; id = idr_alloc_cyclic(&ctx->personality_idr, (void *) creds, 1, USHRT_MAX, GFP_KERNEL); if (id < 0) put_cred(creds); return id; } static int io_unregister_personality(struct io_ring_ctx *ctx, unsigned id) { const struct cred *old_creds; old_creds = idr_remove(&ctx->personality_idr, id); if (old_creds) { put_cred(old_creds); return 0; } return -EINVAL; } static bool io_register_op_must_quiesce(int op) { switch (op) { case IORING_UNREGISTER_FILES: case IORING_REGISTER_FILES_UPDATE: case IORING_REGISTER_PROBE: case IORING_REGISTER_PERSONALITY: case IORING_UNREGISTER_PERSONALITY: return false; default: return true; } } static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode, void __user *arg, unsigned nr_args) __releases(ctx->uring_lock) __acquires(ctx->uring_lock) { int ret; /* * We're inside the ring mutex, if the ref is already dying, then * someone else killed the ctx or is already going through * io_uring_register(). */ if (percpu_ref_is_dying(&ctx->refs)) return -ENXIO; if (io_register_op_must_quiesce(opcode)) { percpu_ref_kill(&ctx->refs); /* * Drop uring mutex before waiting for references to exit. If * another thread is currently inside io_uring_enter() it might * need to grab the uring_lock to make progress. If we hold it * here across the drain wait, then we can deadlock. It's safe * to drop the mutex here, since no new references will come in * after we've killed the percpu ref. */ mutex_unlock(&ctx->uring_lock); ret = wait_for_completion_interruptible(&ctx->ref_comp); mutex_lock(&ctx->uring_lock); if (ret) { percpu_ref_resurrect(&ctx->refs); ret = -EINTR; goto out; } } switch (opcode) { case IORING_REGISTER_BUFFERS: ret = io_sqe_buffer_register(ctx, arg, nr_args); break; case IORING_UNREGISTER_BUFFERS: ret = -EINVAL; if (arg || nr_args) break; ret = io_sqe_buffer_unregister(ctx); break; case IORING_REGISTER_FILES: ret = io_sqe_files_register(ctx, arg, nr_args); break; case IORING_UNREGISTER_FILES: ret = -EINVAL; if (arg || nr_args) break; ret = io_sqe_files_unregister(ctx); break; case IORING_REGISTER_FILES_UPDATE: ret = io_sqe_files_update(ctx, arg, nr_args); break; case IORING_REGISTER_EVENTFD: case IORING_REGISTER_EVENTFD_ASYNC: ret = -EINVAL; if (nr_args != 1) break; ret = io_eventfd_register(ctx, arg); if (ret) break; if (opcode == IORING_REGISTER_EVENTFD_ASYNC) ctx->eventfd_async = 1; else ctx->eventfd_async = 0; break; case IORING_UNREGISTER_EVENTFD: ret = -EINVAL; if (arg || nr_args) break; ret = io_eventfd_unregister(ctx); break; case IORING_REGISTER_PROBE: ret = -EINVAL; if (!arg || nr_args > 256) break; ret = io_probe(ctx, arg, nr_args); break; case IORING_REGISTER_PERSONALITY: ret = -EINVAL; if (arg || nr_args) break; ret = io_register_personality(ctx); break; case IORING_UNREGISTER_PERSONALITY: ret = -EINVAL; if (arg) break; ret = io_unregister_personality(ctx, nr_args); break; default: ret = -EINVAL; break; } if (io_register_op_must_quiesce(opcode)) { /* bring the ctx back to life */ percpu_ref_reinit(&ctx->refs); out: reinit_completion(&ctx->ref_comp); } return ret; } SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode, void __user *, arg, unsigned int, nr_args) { struct io_ring_ctx *ctx; long ret = -EBADF; struct fd f; f = fdget(fd); if (!f.file) return -EBADF; ret = -EOPNOTSUPP; if (f.file->f_op != &io_uring_fops) goto out_fput; ctx = f.file->private_data; mutex_lock(&ctx->uring_lock); ret = __io_uring_register(ctx, opcode, arg, nr_args); mutex_unlock(&ctx->uring_lock); trace_io_uring_register(ctx, opcode, ctx->nr_user_files, ctx->nr_user_bufs, ctx->cq_ev_fd != NULL, ret); out_fput: fdput(f); return ret; } static int __init io_uring_init(void) { #define __BUILD_BUG_VERIFY_ELEMENT(stype, eoffset, etype, ename) do { \ BUILD_BUG_ON(offsetof(stype, ename) != eoffset); \ BUILD_BUG_ON(sizeof(etype) != sizeof_field(stype, ename)); \ } while (0) #define BUILD_BUG_SQE_ELEM(eoffset, etype, ename) \ __BUILD_BUG_VERIFY_ELEMENT(struct io_uring_sqe, eoffset, etype, ename) BUILD_BUG_ON(sizeof(struct io_uring_sqe) != 64); BUILD_BUG_SQE_ELEM(0, __u8, opcode); BUILD_BUG_SQE_ELEM(1, __u8, flags); BUILD_BUG_SQE_ELEM(2, __u16, ioprio); BUILD_BUG_SQE_ELEM(4, __s32, fd); BUILD_BUG_SQE_ELEM(8, __u64, off); BUILD_BUG_SQE_ELEM(8, __u64, addr2); BUILD_BUG_SQE_ELEM(16, __u64, addr); BUILD_BUG_SQE_ELEM(16, __u64, splice_off_in); BUILD_BUG_SQE_ELEM(24, __u32, len); BUILD_BUG_SQE_ELEM(28, __kernel_rwf_t, rw_flags); BUILD_BUG_SQE_ELEM(28, /* compat */ int, rw_flags); BUILD_BUG_SQE_ELEM(28, /* compat */ __u32, rw_flags); BUILD_BUG_SQE_ELEM(28, __u32, fsync_flags); BUILD_BUG_SQE_ELEM(28, /* compat */ __u16, poll_events); BUILD_BUG_SQE_ELEM(28, __u32, poll32_events); BUILD_BUG_SQE_ELEM(28, __u32, sync_range_flags); BUILD_BUG_SQE_ELEM(28, __u32, msg_flags); BUILD_BUG_SQE_ELEM(28, __u32, timeout_flags); BUILD_BUG_SQE_ELEM(28, __u32, accept_flags); BUILD_BUG_SQE_ELEM(28, __u32, cancel_flags); BUILD_BUG_SQE_ELEM(28, __u32, open_flags); BUILD_BUG_SQE_ELEM(28, __u32, statx_flags); BUILD_BUG_SQE_ELEM(28, __u32, fadvise_advice); BUILD_BUG_SQE_ELEM(28, __u32, splice_flags); BUILD_BUG_SQE_ELEM(32, __u64, user_data); BUILD_BUG_SQE_ELEM(40, __u16, buf_index); BUILD_BUG_SQE_ELEM(42, __u16, personality); BUILD_BUG_SQE_ELEM(44, __s32, splice_fd_in); BUILD_BUG_ON(ARRAY_SIZE(io_op_defs) != IORING_OP_LAST); BUILD_BUG_ON(__REQ_F_LAST_BIT >= 8 * sizeof(int)); req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC); return 0; }; __initcall(io_uring_init);