Re: [PATCH] splice: pass a poll key when waking pipe readers and writers

[Breno Leitao <leitao@debian.org>]

On Wed, Sep 16, 2026 at 12:57:13PM +0200, Oleg Nesterov wrote:
> While at it... I think they both should use wq_has_sleeper().

Good point, thanks!

> If you agree, feel free to send V2 with this additional change.

Sure, let's wait a bit more before I send v2, but I've got this fix updated
already to the following change:

	diff --git a/fs/splice.c b/fs/splice.c
	index 9d8f63e2fd1ab..65f9090c3438c 100644
	--- a/fs/splice.c
	+++ b/fs/splice.c
	@@ -177,9 +177,9 @@ static const struct pipe_buf_operations user_page_pipe_buf_ops = {

	static void wakeup_pipe_readers(struct pipe_inode_info *pipe)
	{
	-       smp_mb();
	-       if (waitqueue_active(&pipe->rd_wait))
	-               wake_up_interruptible(&pipe->rd_wait);
	+       if (wq_has_sleeper(&pipe->rd_wait))
	+               wake_up_interruptible_poll(&pipe->rd_wait,
	+                                          EPOLLIN | EPOLLRDNORM);
		kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
	}

	@@ -413,9 +413,9 @@ EXPORT_SYMBOL(nosteal_pipe_buf_ops);

	static void wakeup_pipe_writers(struct pipe_inode_info *pipe)
	{
	-       smp_mb();
	-       if (waitqueue_active(&pipe->wr_wait))
	-               wake_up_interruptible(&pipe->wr_wait);
	+       if (wq_has_sleeper(&pipe->wr_wait))
	+               wake_up_interruptible_poll(&pipe->wr_wait,
	+                                          EPOLLOUT | EPOLLWRNORM);
		kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
	}


Thanks for the quick review,
--breno