io_uring: reshuffle io_submit_state bits

struct io_submit_state's ->free_list and ->link are hotter and smaller
than ->plug, place them first.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/6ad3c15849f50b27ad012c042c73e6e069d22df7.1633532552.git.asml.silence@gmail.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -308,19 +308,15 @@ struct io_submit_link {
 };
 
 struct io_submit_state {
-	struct blk_plug		plug;
+	/* inline/task_work completion list, under ->uring_lock */
+	struct io_wq_work_node	free_list;
+	/* batch completion logic */
+	struct io_wq_work_list	compl_reqs;
 	struct io_submit_link	link;
 
 	bool			plug_started;
 	bool			need_plug;
-
-	/*
-	 * Batch completion logic
-	 */
-	struct io_wq_work_list	compl_reqs;
-
-	/* inline/task_work completion list, under ->uring_lock */
-	struct io_wq_work_node	free_list;
+	struct blk_plug		plug;
 };
 
 struct io_ring_ctx {