[PATCH 1/1] io_uring: remove extra nxt check after punt

[PATCH 1/1] io_uring: remove extra nxt check after punt

[Pavel Begunkov]

After __io_queue_sqe() ended up in io_queue_async_work(), it's already
known that there is no @nxt req, so skip the check and return from the
function.

Also, @nxt initialisation now can be done just before
io_put_req_find_next(), as there is no jumping until it's checked.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 fs/io_uring.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 8d8d93adb9c2..74498c9cd023 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4931,7 +4931,7 @@ static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req)
 static void __io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
 	struct io_kiocb *linked_timeout;
-	struct io_kiocb *nxt = NULL;
+	struct io_kiocb *nxt;
 	const struct cred *old_creds = NULL;
 	int ret;
 
@@ -4958,7 +4958,7 @@ static void __io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 		if (io_arm_poll_handler(req)) {
 			if (linked_timeout)
 				io_queue_linked_timeout(linked_timeout);
-			goto done_req;
+			goto exit;
 		}
 punt:
 		if (io_op_defs[req->opcode].file_table) {
@@ -4972,10 +4972,11 @@ static void __io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 		 * submit reference when the iocb is actually submitted.
 		 */
 		io_queue_async_work(req);
-		goto done_req;
+		goto exit;
 	}
 
 err:
+	nxt = NULL;
 	/* drop submission reference */
 	io_put_req_find_next(req, &nxt);
 
@@ -4992,15 +4993,14 @@ static void __io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 		req_set_fail_links(req);
 		io_put_req(req);
 	}
-done_req:
 	if (nxt) {
 		req = nxt;
-		nxt = NULL;
 
 		if (req->flags & REQ_F_FORCE_ASYNC)
 			goto punt;
 		goto again;
 	}
+exit:
 	if (old_creds)
 		revert_creds(old_creds);
 }
-- 
2.24.0

Re: [PATCH 1/1] io_uring: remove extra nxt check after punt

[Jens Axboe]

On 2/29/20 12:48 PM, Pavel Begunkov wrote:
> After __io_queue_sqe() ended up in io_queue_async_work(), it's already
> known that there is no @nxt req, so skip the check and return from the
> function.
> 
> Also, @nxt initialisation now can be done just before
> io_put_req_find_next(), as there is no jumping until it's checked.

Applied, thanks.

-- 
Jens Axboe