Unverified Commit dfaabf91 authored by Max Kellermann's avatar Max Kellermann Committed by Christian Brauner
Browse files

fs/pipe: remove unnecessary spinlock from pipe_write() 



This reverts commit 8df44129 ("pipe: Check for ring full inside of
the spinlock in pipe_write()") which was obsoleted by commit
c73be61c ("pipe: Add general notification queue support") because
now pipe_write() fails early with -EXDEV if there is a watch_queue.

Without a watch_queue, no notifications can be posted to the pipe and
mutex protection is enough, as can be seen in splice_pipe_to_pipe()
which does not use the spinlock either.

Signed-off-by: default avatarMax Kellermann <max.kellermann@ionos.com>
Message-Id: <20230921075755.1378787-3-max.kellermann@ionos.com>
Reviewed-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent b4bd6b4b

fs/pipe.c

+0 −9
Original line number Diff line number Diff line
@@ -505,16 +505,7 @@ 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];