Advance the pipe ring tail pointer inside of wait spinlock in pipe_read()
so that the pipe can be written into with kernel notifications from
contexts where pipe->mutex cannot be taken.
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
---
fs/pipe.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/fs/pipe.c b/fs/pipe.c
index 69afeab8a73a..ea134f69a292 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -325,9 +325,14 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
if (!buf->len) {
pipe_buf_release(pipe, buf);
+ spin_lock_irq(&pipe->wait.lock);
tail++;
pipe->tail = tail;
- do_wakeup = 1;
+ do_wakeup = 0;
+ wake_up_interruptible_sync_poll_locked(
+ &pipe->wait, EPOLLOUT | EPOLLWRNORM);
+ spin_unlock_irq(&pipe->wait.lock);
+ kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
}
total_len -= chars;
if (!total_len)
@@ -359,6 +364,7 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
if (do_wakeup) {
wake_up_interruptible_sync_poll(&pipe->wait, EPOLLOUT | EPOLLWRNORM);
kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
+ do_wakeup = 0;
}
pipe_wait(pipe);
}
