diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/pipe.c | 30 |
1 files changed, 27 insertions, 3 deletions
diff --git a/fs/pipe.c b/fs/pipe.c index 58f236c65bea..87109e761fa5 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -270,6 +270,16 @@ static bool pipe_buf_can_merge(struct pipe_buffer *buf) return buf->ops == &anon_pipe_buf_ops; } +/* Done while waiting without holding the pipe lock - thus the READ_ONCE() */ +static inline bool pipe_readable(const struct pipe_inode_info *pipe) +{ + unsigned int head = READ_ONCE(pipe->head); + unsigned int tail = READ_ONCE(pipe->tail); + unsigned int writers = READ_ONCE(pipe->writers); + + return !pipe_empty(head, tail) || !writers; +} + static ssize_t pipe_read(struct kiocb *iocb, struct iov_iter *to) { @@ -359,11 +369,13 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to) ret = -ERESTARTSYS; break; } + __pipe_unlock(pipe); if (was_full) { wake_up_interruptible_sync_poll(&pipe->wait, EPOLLOUT | EPOLLWRNORM); kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); } - pipe_wait(pipe); + wait_event_interruptible(pipe->wait, pipe_readable(pipe)); + __pipe_lock(pipe); was_full = pipe_full(pipe->head, pipe->tail, pipe->max_usage); } __pipe_unlock(pipe); @@ -382,6 +394,17 @@ static inline int is_packetized(struct file *file) return (file->f_flags & O_DIRECT) != 0; } +/* Done while waiting without holding the pipe lock - thus the READ_ONCE() */ +static inline bool pipe_writable(const struct pipe_inode_info *pipe) +{ + unsigned int head = READ_ONCE(pipe->head); + unsigned int tail = READ_ONCE(pipe->tail); + unsigned int max_usage = READ_ONCE(pipe->max_usage); + + return !pipe_full(head, tail, max_usage) || + !READ_ONCE(pipe->readers); +} + static ssize_t pipe_write(struct kiocb *iocb, struct iov_iter *from) { @@ -529,12 +552,13 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from) * after waiting we need to re-check whether the pipe * become empty while we dropped the lock. */ + __pipe_unlock(pipe); if (was_empty) { wake_up_interruptible_sync_poll(&pipe->wait, EPOLLIN | EPOLLRDNORM); kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); } - pipe_wait(pipe); - + wait_event_interruptible(pipe->wait, pipe_writable(pipe)); + __pipe_lock(pipe); was_empty = pipe_empty(head, pipe->tail); } out: |