io_uring: micro optimization of __io_sq_thread() condition

reverse the order of the element evaluation in an if statement.

for many users that are not using iopoll, the iopoll_list will always
evaluate to false after having made a memory access whereas to_submit is
very likely already loaded in a register.

Signed-off-by: Olivier Langlois <[email protected]>
Reviewed-by: Pavel Begunkov <[email protected]>
Link: https://lore.kernel.org/r/052ca60b5c49e7439e4b8bd33bfab4a09d36d3d6.1722374371.git.olivier@trillion01.com
Signed-off-by: Jens Axboe <[email protected]>

Author: Olivier Langlois

io_uring/sqpoll.c

@@ -176,7 +176,7 @@ static int __io_sq_thread(struct io_ring_ctx *ctx, bool cap_entries)
 	if (cap_entries && to_submit > IORING_SQPOLL_CAP_ENTRIES_VALUE)
 		to_submit = IORING_SQPOLL_CAP_ENTRIES_VALUE;
 
-	if (!wq_list_empty(&ctx->iopoll_list) || to_submit) {
+	if (to_submit || !wq_list_empty(&ctx->iopoll_list)) {
 		const struct cred *creds = NULL;
 
 		if (ctx->sq_creds != current_cred())