diff options
Diffstat (limited to 'fs/pipe.c')
-rw-r--r-- | fs/pipe.c | 64 |
1 files changed, 35 insertions, 29 deletions
diff --git a/fs/pipe.c b/fs/pipe.c index 139190165a1c..485e3be8903c 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -227,6 +227,36 @@ static inline bool pipe_readable(const struct pipe_inode_info *pipe) return !pipe_empty(head, tail) || !writers; } +static inline unsigned int pipe_update_tail(struct pipe_inode_info *pipe, + struct pipe_buffer *buf, + unsigned int tail) +{ + pipe_buf_release(pipe, buf); + + /* + * If the pipe has a watch_queue, we need additional protection + * by the spinlock because notifications get posted with only + * this spinlock, no mutex + */ + if (pipe_has_watch_queue(pipe)) { + spin_lock_irq(&pipe->rd_wait.lock); +#ifdef CONFIG_WATCH_QUEUE + if (buf->flags & PIPE_BUF_FLAG_LOSS) + pipe->note_loss = true; +#endif + pipe->tail = ++tail; + spin_unlock_irq(&pipe->rd_wait.lock); + return tail; + } + + /* + * Without a watch_queue, we can simply increment the tail + * without the spinlock - the mutex is enough. + */ + pipe->tail = ++tail; + return tail; +} + static ssize_t pipe_read(struct kiocb *iocb, struct iov_iter *to) { @@ -320,17 +350,8 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to) buf->len = 0; } - if (!buf->len) { - pipe_buf_release(pipe, buf); - spin_lock_irq(&pipe->rd_wait.lock); -#ifdef CONFIG_WATCH_QUEUE - if (buf->flags & PIPE_BUF_FLAG_LOSS) - pipe->note_loss = true; -#endif - tail++; - pipe->tail = tail; - spin_unlock_irq(&pipe->rd_wait.lock); - } + if (!buf->len) + tail = pipe_update_tail(pipe, buf, tail); total_len -= chars; if (!total_len) break; /* common path: read succeeded */ @@ -437,12 +458,10 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from) goto out; } -#ifdef CONFIG_WATCH_QUEUE - if (pipe->watch_queue) { + if (pipe_has_watch_queue(pipe)) { ret = -EXDEV; goto out; } -#endif /* * If it wasn't empty we try to merge new data into @@ -507,16 +526,7 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from) * it, either the reader will consume it or it'll still * be there for the next write. */ - spin_lock_irq(&pipe->rd_wait.lock); - - head = pipe->head; - if (pipe_full(head, pipe->tail, pipe->max_usage)) { - spin_unlock_irq(&pipe->rd_wait.lock); - continue; - } - pipe->head = head + 1; - spin_unlock_irq(&pipe->rd_wait.lock); /* Insert it into the buffer array */ buf = &pipe->bufs[head & mask]; @@ -1324,10 +1334,8 @@ static long pipe_set_size(struct pipe_inode_info *pipe, unsigned int arg) unsigned int nr_slots, size; long ret = 0; -#ifdef CONFIG_WATCH_QUEUE - if (pipe->watch_queue) + if (pipe_has_watch_queue(pipe)) return -EBUSY; -#endif size = round_pipe_size(arg); nr_slots = size >> PAGE_SHIFT; @@ -1379,10 +1387,8 @@ struct pipe_inode_info *get_pipe_info(struct file *file, bool for_splice) if (file->f_op != &pipefifo_fops || !pipe) return NULL; -#ifdef CONFIG_WATCH_QUEUE - if (for_splice && pipe->watch_queue) + if (for_splice && pipe_has_watch_queue(pipe)) return NULL; -#endif return pipe; } |