Commit 66fc25ca authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: shuffle io_eventfd_signal() bits around 



A preparation patch, which moves a fast ->io_ev_fd check out of
io_eventfd_signal() into ev_posted*(). Compilers are smart enough for it
to not change anything, but will need it later.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/ec4091ac76d43912b73917e8db651c2dac4b7b01.1647481208.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 0f847471

fs/io_uring.c

+5 −8
Original line number Diff line number Diff line
@@ -1828,10 +1828,6 @@ static void io_eventfd_signal(struct io_ring_ctx *ctx) 
{

	struct io_ev_fd *ev_fd;



	/* Return quickly if ctx->io_ev_fd doesn't exist */

	if (likely(!rcu_dereference_raw(ctx->io_ev_fd)))

		return;



	rcu_read_lock();

	/*

	 * rcu_dereference ctx->io_ev_fd once and use it for both for checking
@@ -1851,7 +1847,6 @@ static void io_eventfd_signal(struct io_ring_ctx *ctx) 


	if (!ev_fd->eventfd_async || io_wq_current_is_worker())

		eventfd_signal(ev_fd->cq_ev_fd, 1);



out:

	rcu_read_unlock();

}
@@ -1863,7 +1858,7 @@ static void io_eventfd_signal(struct io_ring_ctx *ctx) 
 * 1:1 relationship between how many times this function is called (and

 * hence the eventfd count) and number of CQEs posted to the CQ ring.

 */

static void io_cqring_ev_posted(struct io_ring_ctx *ctx)

static inline void io_cqring_ev_posted(struct io_ring_ctx *ctx)

{

	/*

	 * wake_up_all() may seem excessive, but io_wake_function() and
@@ -1872,6 +1867,7 @@ static void io_cqring_ev_posted(struct io_ring_ctx *ctx) 
	 */

	if (wq_has_sleeper(&ctx->cq_wait))

		wake_up_all(&ctx->cq_wait);

	if (unlikely(rcu_dereference_raw(ctx->io_ev_fd)))

		io_eventfd_signal(ctx);

}
@@ -1881,6 +1877,7 @@ static void io_cqring_ev_posted_iopoll(struct io_ring_ctx *ctx) 
		if (wq_has_sleeper(&ctx->cq_wait))

			wake_up_all(&ctx->cq_wait);

	}

	if (unlikely(rcu_dereference_raw(ctx->io_ev_fd)))

		io_eventfd_signal(ctx);

}