io_uring: keep queue_sqe()'s fail path separately

A preparation path, extracts error path into a separate block. It looks
saner then calling req_set_fail_links() after io_put_req_find_next(), even
though it have been working well.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -5937,22 +5937,21 @@ static void __io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 		goto exit;
 	}
 
+	if (unlikely(ret)) {
 err:
-	/* drop submission reference */
-	nxt = io_put_req_find_next(req);
-
-	if (linked_timeout) {
-		if (!ret)
-			io_queue_linked_timeout(linked_timeout);
-		else
-			io_put_req(linked_timeout);
-	}
-
-	/* and drop final reference, if we failed */
-	if (ret) {
+		/* un-prep timeout, so it'll be killed as any other linked */
+		req->flags &= ~REQ_F_LINK_TIMEOUT;
 		req_set_fail_links(req);
+		io_put_req(req);
 		io_req_complete(req, ret);
+		goto exit;
 	}
+
+	/* drop submission reference */
+	nxt = io_put_req_find_next(req);
+	if (linked_timeout)
+		io_queue_linked_timeout(linked_timeout);
+
 	if (nxt) {
 		req = nxt;