diff options
Diffstat (limited to 'fs/proc/proc_sysctl.c')
-rw-r--r-- | fs/proc/proc_sysctl.c | 113 |
1 files changed, 60 insertions, 53 deletions
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index d11ebc055ce0..27a283d85a6e 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -17,6 +17,7 @@ #include <linux/bpf-cgroup.h> #include <linux/mount.h> #include <linux/kmemleak.h> +#include <linux/lockdep.h> #include "internal.h" #define list_for_each_table_entry(entry, header) \ @@ -33,7 +34,7 @@ static const struct inode_operations proc_sys_dir_operations; * Support for permanently empty directories. * Must be non-empty to avoid sharing an address with other tables. */ -static struct ctl_table sysctl_mount_point[] = { +static const struct ctl_table sysctl_mount_point[] = { { } }; @@ -67,7 +68,7 @@ void proc_sys_poll_notify(struct ctl_table_poll *poll) wake_up_interruptible(&poll->wait); } -static struct ctl_table root_table[] = { +static const struct ctl_table root_table[] = { { .procname = "", .mode = S_IFDIR|S_IRUGO|S_IXUGO, @@ -88,7 +89,7 @@ static DEFINE_SPINLOCK(sysctl_lock); static void drop_sysctl_table(struct ctl_table_header *header); static int sysctl_follow_link(struct ctl_table_header **phead, - struct ctl_table **pentry); + const struct ctl_table **pentry); static int insert_links(struct ctl_table_header *head); static void put_links(struct ctl_table_header *header); @@ -109,14 +110,15 @@ static int namecmp(const char *name1, int len1, const char *name2, int len2) return cmp; } -/* Called under sysctl_lock */ -static struct ctl_table *find_entry(struct ctl_table_header **phead, +static const struct ctl_table *find_entry(struct ctl_table_header **phead, struct ctl_dir *dir, const char *name, int namelen) { struct ctl_table_header *head; - struct ctl_table *entry; + const struct ctl_table *entry; struct rb_node *node = dir->root.rb_node; + lockdep_assert_held(&sysctl_lock); + while (node) { struct ctl_node *ctl_node; @@ -141,7 +143,7 @@ static struct ctl_table *find_entry(struct ctl_table_header **phead, return NULL; } -static int insert_entry(struct ctl_table_header *head, struct ctl_table *entry) +static int insert_entry(struct ctl_table_header *head, const struct ctl_table *entry) { struct rb_node *node = &head->node[entry - head->ctl_table].node; struct rb_node **p = &head->parent->root.rb_node; @@ -151,7 +153,7 @@ static int insert_entry(struct ctl_table_header *head, struct ctl_table *entry) while (*p) { struct ctl_table_header *parent_head; - struct ctl_table *parent_entry; + const struct ctl_table *parent_entry; struct ctl_node *parent_node; const char *parent_name; int cmp; @@ -180,7 +182,7 @@ static int insert_entry(struct ctl_table_header *head, struct ctl_table *entry) return 0; } -static void erase_entry(struct ctl_table_header *head, struct ctl_table *entry) +static void erase_entry(struct ctl_table_header *head, const struct ctl_table *entry) { struct rb_node *node = &head->node[entry - head->ctl_table].node; @@ -189,7 +191,7 @@ static void erase_entry(struct ctl_table_header *head, struct ctl_table *entry) static void init_header(struct ctl_table_header *head, struct ctl_table_root *root, struct ctl_table_set *set, - struct ctl_node *node, struct ctl_table *table, size_t table_size) + struct ctl_node *node, const struct ctl_table *table, size_t table_size) { head->ctl_table = table; head->ctl_table_size = table_size; @@ -204,7 +206,7 @@ static void init_header(struct ctl_table_header *head, head->node = node; INIT_HLIST_HEAD(&head->inodes); if (node) { - struct ctl_table *entry; + const struct ctl_table *entry; list_for_each_table_entry(entry, head) { node->header = head; @@ -217,7 +219,7 @@ static void init_header(struct ctl_table_header *head, static void erase_header(struct ctl_table_header *head) { - struct ctl_table *entry; + const struct ctl_table *entry; list_for_each_table_entry(entry, head) erase_entry(head, entry); @@ -225,7 +227,7 @@ static void erase_header(struct ctl_table_header *head) static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header) { - struct ctl_table *entry; + const struct ctl_table *entry; struct ctl_table_header *dir_h = &dir->header; int err; @@ -263,18 +265,20 @@ fail_links: return err; } -/* called under sysctl_lock */ static int use_table(struct ctl_table_header *p) { + lockdep_assert_held(&sysctl_lock); + if (unlikely(p->unregistering)) return 0; p->used++; return 1; } -/* called under sysctl_lock */ static void unuse_table(struct ctl_table_header *p) { + lockdep_assert_held(&sysctl_lock); + if (!--p->used) if (unlikely(p->unregistering)) complete(p->unregistering); @@ -285,9 +289,11 @@ static void proc_sys_invalidate_dcache(struct ctl_table_header *head) proc_invalidate_siblings_dcache(&head->inodes, &sysctl_lock); } -/* called under sysctl_lock, will reacquire if has to wait */ static void start_unregistering(struct ctl_table_header *p) { + /* will reacquire if has to wait */ + lockdep_assert_held(&sysctl_lock); + /* * if p->used is 0, nobody will ever touch that entry again; * we'll eliminate all paths to it before dropping sysctl_lock @@ -344,12 +350,12 @@ lookup_header_set(struct ctl_table_root *root) return set; } -static struct ctl_table *lookup_entry(struct ctl_table_header **phead, - struct ctl_dir *dir, - const char *name, int namelen) +static const struct ctl_table *lookup_entry(struct ctl_table_header **phead, + struct ctl_dir *dir, + const char *name, int namelen) { struct ctl_table_header *head; - struct ctl_table *entry; + const struct ctl_table *entry; spin_lock(&sysctl_lock); entry = find_entry(&head, dir, name, namelen); @@ -374,10 +380,10 @@ static struct ctl_node *first_usable_entry(struct rb_node *node) } static void first_entry(struct ctl_dir *dir, - struct ctl_table_header **phead, struct ctl_table **pentry) + struct ctl_table_header **phead, const struct ctl_table **pentry) { struct ctl_table_header *head = NULL; - struct ctl_table *entry = NULL; + const struct ctl_table *entry = NULL; struct ctl_node *ctl_node; spin_lock(&sysctl_lock); @@ -391,10 +397,10 @@ static void first_entry(struct ctl_dir *dir, *pentry = entry; } -static void next_entry(struct ctl_table_header **phead, struct ctl_table **pentry) +static void next_entry(struct ctl_table_header **phead, const struct ctl_table **pentry) { struct ctl_table_header *head = *phead; - struct ctl_table *entry = *pentry; + const struct ctl_table *entry = *pentry; struct ctl_node *ctl_node = &head->node[entry - head->ctl_table]; spin_lock(&sysctl_lock); @@ -427,7 +433,7 @@ static int test_perm(int mode, int op) return -EACCES; } -static int sysctl_perm(struct ctl_table_header *head, struct ctl_table *table, int op) +static int sysctl_perm(struct ctl_table_header *head, const struct ctl_table *table, int op) { struct ctl_table_root *root = head->root; int mode; @@ -441,7 +447,7 @@ static int sysctl_perm(struct ctl_table_header *head, struct ctl_table *table, i } static struct inode *proc_sys_make_inode(struct super_block *sb, - struct ctl_table_header *head, struct ctl_table *table) + struct ctl_table_header *head, const struct ctl_table *table) { struct ctl_table_root *root = head->root; struct inode *inode; @@ -512,7 +518,7 @@ static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, struct ctl_table_header *head = grab_header(dir); struct ctl_table_header *h = NULL; const struct qstr *name = &dentry->d_name; - struct ctl_table *p; + const struct ctl_table *p; struct inode *inode; struct dentry *err = ERR_PTR(-ENOENT); struct ctl_dir *ctl_dir; @@ -550,7 +556,7 @@ static ssize_t proc_sys_call_handler(struct kiocb *iocb, struct iov_iter *iter, { struct inode *inode = file_inode(iocb->ki_filp); struct ctl_table_header *head = grab_header(inode); - struct ctl_table *table = PROC_I(inode)->sysctl_entry; + const struct ctl_table *table = PROC_I(inode)->sysctl_entry; size_t count = iov_iter_count(iter); char *kbuf; ssize_t error; @@ -624,7 +630,7 @@ static ssize_t proc_sys_write(struct kiocb *iocb, struct iov_iter *iter) static int proc_sys_open(struct inode *inode, struct file *filp) { struct ctl_table_header *head = grab_header(inode); - struct ctl_table *table = PROC_I(inode)->sysctl_entry; + const struct ctl_table *table = PROC_I(inode)->sysctl_entry; /* sysctl was unregistered */ if (IS_ERR(head)) @@ -642,7 +648,7 @@ static __poll_t proc_sys_poll(struct file *filp, poll_table *wait) { struct inode *inode = file_inode(filp); struct ctl_table_header *head = grab_header(inode); - struct ctl_table *table = PROC_I(inode)->sysctl_entry; + const struct ctl_table *table = PROC_I(inode)->sysctl_entry; __poll_t ret = DEFAULT_POLLMASK; unsigned long event; @@ -673,7 +679,7 @@ out: static bool proc_sys_fill_cache(struct file *file, struct dir_context *ctx, struct ctl_table_header *head, - struct ctl_table *table) + const struct ctl_table *table) { struct dentry *child, *dir = file->f_path.dentry; struct inode *inode; @@ -698,11 +704,11 @@ static bool proc_sys_fill_cache(struct file *file, res = d_splice_alias(inode, child); d_lookup_done(child); if (unlikely(res)) { - if (IS_ERR(res)) { - dput(child); - return false; - } dput(child); + + if (IS_ERR(res)) + return false; + child = res; } } @@ -717,7 +723,7 @@ static bool proc_sys_fill_cache(struct file *file, static bool proc_sys_link_fill_cache(struct file *file, struct dir_context *ctx, struct ctl_table_header *head, - struct ctl_table *table) + const struct ctl_table *table) { bool ret = true; @@ -735,7 +741,7 @@ out: return ret; } -static int scan(struct ctl_table_header *head, struct ctl_table *table, +static int scan(struct ctl_table_header *head, const struct ctl_table *table, unsigned long *pos, struct file *file, struct dir_context *ctx) { @@ -759,7 +765,7 @@ static int proc_sys_readdir(struct file *file, struct dir_context *ctx) { struct ctl_table_header *head = grab_header(file_inode(file)); struct ctl_table_header *h = NULL; - struct ctl_table *entry; + const struct ctl_table *entry; struct ctl_dir *ctl_dir; unsigned long pos; @@ -792,7 +798,7 @@ static int proc_sys_permission(struct mnt_idmap *idmap, * are _NOT_ writeable, capabilities or not. */ struct ctl_table_header *head; - struct ctl_table *table; + const struct ctl_table *table; int error; /* Executable files are not allowed under /proc/sys/ */ @@ -836,7 +842,7 @@ static int proc_sys_getattr(struct mnt_idmap *idmap, { struct inode *inode = d_inode(path->dentry); struct ctl_table_header *head = grab_header(inode); - struct ctl_table *table = PROC_I(inode)->sysctl_entry; + const struct ctl_table *table = PROC_I(inode)->sysctl_entry; if (IS_ERR(head)) return PTR_ERR(head); @@ -935,7 +941,7 @@ static struct ctl_dir *find_subdir(struct ctl_dir *dir, const char *name, int namelen) { struct ctl_table_header *head; - struct ctl_table *entry; + const struct ctl_table *entry; entry = find_entry(&head, dir, name, namelen); if (!entry) @@ -1046,12 +1052,12 @@ static struct ctl_dir *xlate_dir(struct ctl_table_set *set, struct ctl_dir *dir) } static int sysctl_follow_link(struct ctl_table_header **phead, - struct ctl_table **pentry) + const struct ctl_table **pentry) { struct ctl_table_header *head; + const struct ctl_table *entry; struct ctl_table_root *root; struct ctl_table_set *set; - struct ctl_table *entry; struct ctl_dir *dir; int ret; @@ -1078,7 +1084,7 @@ static int sysctl_follow_link(struct ctl_table_header **phead, return ret; } -static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...) +static int sysctl_err(const char *path, const struct ctl_table *table, char *fmt, ...) { struct va_format vaf; va_list args; @@ -1094,7 +1100,7 @@ static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...) return -EINVAL; } -static int sysctl_check_table_array(const char *path, struct ctl_table *table) +static int sysctl_check_table_array(const char *path, const struct ctl_table *table) { unsigned int extra; int err = 0; @@ -1133,7 +1139,7 @@ static int sysctl_check_table_array(const char *path, struct ctl_table *table) static int sysctl_check_table(const char *path, struct ctl_table_header *header) { - struct ctl_table *entry; + const struct ctl_table *entry; int err = 0; list_for_each_table_entry(entry, header) { if (!entry->procname) @@ -1169,8 +1175,9 @@ static int sysctl_check_table(const char *path, struct ctl_table_header *header) static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table_header *head) { - struct ctl_table *link_table, *entry, *link; + struct ctl_table *link_table, *link; struct ctl_table_header *links; + const struct ctl_table *entry; struct ctl_node *node; char *link_name; int name_bytes; @@ -1215,7 +1222,7 @@ static bool get_links(struct ctl_dir *dir, struct ctl_table_root *link_root) { struct ctl_table_header *tmp_head; - struct ctl_table *entry, *link; + const struct ctl_table *entry, *link; if (header->ctl_table_size == 0 || sysctl_is_perm_empty_ctl_header(header)) @@ -1358,7 +1365,7 @@ static struct ctl_dir *sysctl_mkdir_p(struct ctl_dir *dir, const char *path) */ struct ctl_table_header *__register_sysctl_table( struct ctl_table_set *set, - const char *path, struct ctl_table *table, size_t table_size) + const char *path, const struct ctl_table *table, size_t table_size) { struct ctl_table_root *root = set->dir.header.root; struct ctl_table_header *header; @@ -1419,7 +1426,7 @@ fail: * * See __register_sysctl_table for more details. */ -struct ctl_table_header *register_sysctl_sz(const char *path, struct ctl_table *table, +struct ctl_table_header *register_sysctl_sz(const char *path, const struct ctl_table *table, size_t table_size) { return __register_sysctl_table(&sysctl_table_root.default_set, @@ -1448,7 +1455,7 @@ EXPORT_SYMBOL(register_sysctl_sz); * * Context: if your base directory does not exist it will be created for you. */ -void __init __register_sysctl_init(const char *path, struct ctl_table *table, +void __init __register_sysctl_init(const char *path, const struct ctl_table *table, const char *table_name, size_t table_size) { struct ctl_table_header *hdr = register_sysctl_sz(path, table, table_size); @@ -1466,7 +1473,7 @@ static void put_links(struct ctl_table_header *header) struct ctl_table_root *root = header->root; struct ctl_dir *parent = header->parent; struct ctl_dir *core_parent; - struct ctl_table *entry; + const struct ctl_table *entry; if (header->set == root_set) return; @@ -1477,7 +1484,7 @@ static void put_links(struct ctl_table_header *header) list_for_each_table_entry(entry, header) { struct ctl_table_header *link_head; - struct ctl_table *link; + const struct ctl_table *link; const char *name = entry->procname; link = find_entry(&link_head, core_parent, name, strlen(name)); |