On 03/04, Mateusz Guzik wrote:
>
> @@ -529,10 +529,9 @@ anon_pipe_write(struct kiocb *iocb, struct iov_iter *from)
>
> if (!iov_iter_count(from))
> break;
> - }
>
> - if (!pipe_full(head, pipe->tail, pipe->max_usage))
> continue;
> + }
Reviewed-by: Oleg Nesterov <oleg@xxxxxxxxxx>
It seems that we can also remove the unnecessary signal_pending()
check, but I need to recheck and we need to cleanup the poll_usage
logic first.
This will also remove the unnecessary wakeups when the writer is
interrupted by signal/
diff --git a/fs/pipe.c b/fs/pipe.c
index b0641f75b1ba..ed55a86ca03b 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -541,12 +541,6 @@ anon_pipe_write(struct kiocb *iocb, struct iov_iter *from)
ret = -EAGAIN;
break;
}
- if (signal_pending(current)) {
- if (!ret)
- ret = -ERESTARTSYS;
- break;
- }
-
/*
* We're going to release the pipe lock and wait for more
* space. We wake up any readers if necessary, and then
@@ -554,10 +548,11 @@ anon_pipe_write(struct kiocb *iocb, struct iov_iter *from)
* become empty while we dropped the lock.
*/
mutex_unlock(&pipe->mutex);
- if (was_empty)
+ if (was_empty || pipe->poll_usage)
wake_up_interruptible_sync_poll(&pipe->rd_wait, EPOLLIN | EPOLLRDNORM);
kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
- wait_event_interruptible_exclusive(pipe->wr_wait, pipe_writable(pipe));
+ if (wait_event_interruptible_exclusive(pipe->wr_wait, pipe_writable(pipe)) < 0)
+ return ret ?: -ERESTARTSYS;
mutex_lock(&pipe->mutex);
was_empty = pipe_empty(pipe->head, pipe->tail);
wake_next_writer = true;
