io_uring: kill off ->inflight_entry field

->inflight_entry is not used anymore after converting everything to
single linked lists, remove it. Also adjust io_kiocb layout, so all hot
bits are in first 3 cachelines.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/fd8d68087ede26c4e1707ce6b175aa1eb2381f2b.1632516769.git.asml.silence@gmail.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -868,18 +868,15 @@ struct io_kiocb {
 	struct percpu_ref		*fixed_rsrc_refs;
 
 	/* used with ctx->iopoll_list with reads/writes */
-	struct list_head		inflight_entry;
+	struct io_wq_work_node		comp_list;
 	struct io_task_work		io_task_work;
 	/* for polled requests, i.e. IORING_OP_POLL_ADD and async armed poll */
 	struct hlist_node		hash_node;
 	struct async_poll		*apoll;
-	struct io_wq_work		work;
-	const struct cred		*creds;
-
-	struct io_wq_work_node		comp_list;
-
 	/* store used ubuf, so we can prevent reloading */
 	struct io_mapped_ubuf		*imu;
+	struct io_wq_work		work;
+	const struct cred		*creds;
 };
 
 struct io_tctx_node {