io_uring: add wrapper type for io_req_tw_func_t arg

In preparation for uring_cmd implementations to implement functions
with the io_req_tw_func_t signature, introduce a wrapper struct
io_tw_req to hide the struct io_kiocb * argument. The intention is for
only the io_uring core to access the inner struct io_kiocb *. uring_cmd
implementations should instead call a helper from io_uring/cmd.h to
convert struct io_tw_req to struct io_uring_cmd *.

Signed-off-by: Caleb Sander Mateos <[e-mail]>
Signed-off-by: Jens Axboe <[e-mail]>

include/linux/io_uring_types.h

···
 	REQ_F_SQE_COPIED	= IO_REQ_FLAG(REQ_F_SQE_COPIED_BIT),
 };
 
-typedef void (*io_req_tw_func_t)(struct io_kiocb *req, io_tw_token_t tw);
+struct io_tw_req {
+	struct io_kiocb *req;
+};
+
+typedef void (*io_req_tw_func_t)(struct io_tw_req tw_req, io_tw_token_t tw);
 
 struct io_task_work {
 	struct llist_node		node;

io_uring/futex.c

···
 	io_alloc_cache_free(&ctx->futex_cache, kfree);
 }
 
-static void __io_futex_complete(struct io_kiocb *req, io_tw_token_t tw)
+static void __io_futex_complete(struct io_tw_req tw_req, io_tw_token_t tw)
 {
-	hlist_del_init(&req->hash_node);
-	io_req_task_complete(req, tw);
+	hlist_del_init(&tw_req.req->hash_node);
+	io_req_task_complete(tw_req, tw);
 }
 
-static void io_futex_complete(struct io_kiocb *req, io_tw_token_t tw)
+static void io_futex_complete(struct io_tw_req tw_req, io_tw_token_t tw)
 {
+	struct io_kiocb *req = tw_req.req;
 	struct io_ring_ctx *ctx = req->ctx;
 
 	io_tw_lock(ctx, tw);
 	io_cache_free(&ctx->futex_cache, req->async_data);
 	io_req_async_data_clear(req, 0);
-	__io_futex_complete(req, tw);
+	__io_futex_complete(tw_req, tw);
 }
 
-static void io_futexv_complete(struct io_kiocb *req, io_tw_token_t tw)
+static void io_futexv_complete(struct io_tw_req tw_req, io_tw_token_t tw)
 {
+	struct io_kiocb *req = tw_req.req;
 	struct io_futex *iof = io_kiocb_to_cmd(req, struct io_futex);
 	struct futex_vector *futexv = req->async_data;
 
···
 	}
 
 	io_req_async_data_free(req);
-	__io_futex_complete(req, tw);
+	__io_futex_complete(tw_req, tw);
 }
 
 static bool io_futexv_claim(struct io_futex *iof)

io_uring/io_uring.c

···
 	mutex_lock(&ctx->uring_lock);
 	ts.cancel = io_should_terminate_tw(ctx);
 	llist_for_each_entry_safe(req, tmp, node, io_task_work.node)
-		req->io_task_work.func(req, ts);
+		req->io_task_work.func((struct io_tw_req){req}, ts);
 	io_submit_flush_completions(ctx);
 	mutex_unlock(&ctx->uring_lock);
 	percpu_ref_put(&ctx->refs);
···
 	io_wq_enqueue(tctx->io_wq, &req->work);
 }
 
-static void io_req_queue_iowq_tw(struct io_kiocb *req, io_tw_token_t tw)
+static void io_req_queue_iowq_tw(struct io_tw_req tw_req, io_tw_token_t tw)
 {
-	io_queue_iowq(req);
+	io_queue_iowq(tw_req.req);
 }
 
 void io_req_queue_iowq(struct io_kiocb *req)
···
 		}
 		INDIRECT_CALL_2(req->io_task_work.func,
 				io_poll_task_func, io_req_rw_complete,
-				req, ts);
+				(struct io_tw_req){req}, ts);
 		node = next;
 		(*count)++;
 		if (unlikely(need_resched())) {
···
 						    io_task_work.node);
 		INDIRECT_CALL_2(req->io_task_work.func,
 				io_poll_task_func, io_req_rw_complete,
-				req, tw);
+				(struct io_tw_req){req}, tw);
 		*node = next;
 		if (++ret >= events)
 			break;
···
 	return ret;
 }
 
-static void io_req_task_cancel(struct io_kiocb *req, io_tw_token_t tw)
+static void io_req_task_cancel(struct io_tw_req tw_req, io_tw_token_t tw)
 {
+	struct io_kiocb *req = tw_req.req;
+
 	io_tw_lock(req->ctx, tw);
 	io_req_defer_failed(req, req->cqe.res);
 }
 
-void io_req_task_submit(struct io_kiocb *req, io_tw_token_t tw)
+void io_req_task_submit(struct io_tw_req tw_req, io_tw_token_t tw)
 {
+	struct io_kiocb *req = tw_req.req;
 	struct io_ring_ctx *ctx = req->ctx;
 
 	io_tw_lock(ctx, tw);
···
 	return 0;
 }
 
-void io_req_task_complete(struct io_kiocb *req, io_tw_token_t tw)
+void io_req_task_complete(struct io_tw_req tw_req, io_tw_token_t tw)
 {
-	io_req_complete_defer(req);
+	io_req_complete_defer(tw_req.req);
 }
 
 /*

io_uring/io_uring.h

···
 void __io_req_task_work_add(struct io_kiocb *req, unsigned flags);
 void io_req_task_work_add_remote(struct io_kiocb *req, unsigned flags);
 void io_req_task_queue(struct io_kiocb *req);
-void io_req_task_complete(struct io_kiocb *req, io_tw_token_t tw);
+void io_req_task_complete(struct io_tw_req tw_req, io_tw_token_t tw);
 void io_req_task_queue_fail(struct io_kiocb *req, int ret);
-void io_req_task_submit(struct io_kiocb *req, io_tw_token_t tw);
+void io_req_task_submit(struct io_tw_req tw_req, io_tw_token_t tw);
 struct llist_node *io_handle_tw_list(struct llist_node *node, unsigned int *count, unsigned int max_entries);
 struct llist_node *tctx_task_work_run(struct io_uring_task *tctx, unsigned int max_entries, unsigned int *count);
 void tctx_task_work(struct callback_head *cb);

io_uring/msg_ring.c

···
 	return target_ctx->task_complete;
 }
 
-static void io_msg_tw_complete(struct io_kiocb *req, io_tw_token_t tw)
+static void io_msg_tw_complete(struct io_tw_req tw_req, io_tw_token_t tw)
 {
+	struct io_kiocb *req = tw_req.req;
 	struct io_ring_ctx *ctx = req->ctx;
 
 	io_add_aux_cqe(ctx, req->cqe.user_data, req->cqe.res, req->cqe.flags);

io_uring/notif.c

···
 
 static const struct ubuf_info_ops io_ubuf_ops;
 
-static void io_notif_tw_complete(struct io_kiocb *notif, io_tw_token_t tw)
+static void io_notif_tw_complete(struct io_tw_req tw_req, io_tw_token_t tw)
 {
+	struct io_kiocb *notif = tw_req.req;
 	struct io_notif_data *nd = io_notif_to_data(notif);
 	struct io_ring_ctx *ctx = notif->ctx;
 
···
 		}
 
 		nd = nd->next;
-		io_req_task_complete(notif, tw);
+		io_req_task_complete((struct io_tw_req){notif}, tw);
 	} while (nd);
 }
 

io_uring/poll.c

···
 	return IOU_POLL_NO_ACTION;
 }
 
-void io_poll_task_func(struct io_kiocb *req, io_tw_token_t tw)
+void io_poll_task_func(struct io_tw_req tw_req, io_tw_token_t tw)
 {
+	struct io_kiocb *req = tw_req.req;
 	int ret;
 
 	ret = io_poll_check_events(req, tw);
···
 			poll = io_kiocb_to_cmd(req, struct io_poll);
 			req->cqe.res = mangle_poll(req->cqe.res & poll->events);
 		} else if (ret == IOU_POLL_REISSUE) {
-			io_req_task_submit(req, tw);
+			io_req_task_submit(tw_req, tw);
 			return;
 		} else if (ret != IOU_POLL_REMOVE_POLL_USE_RES) {
 			req->cqe.res = ret;
···
 		}
 
 		io_req_set_res(req, req->cqe.res, 0);
-		io_req_task_complete(req, tw);
+		io_req_task_complete(tw_req, tw);
 	} else {
 		io_tw_lock(req->ctx, tw);
 
 		if (ret == IOU_POLL_REMOVE_POLL_USE_RES)
-			io_req_task_complete(req, tw);
+			io_req_task_complete(tw_req, tw);
 		else if (ret == IOU_POLL_DONE || ret == IOU_POLL_REISSUE)
-			io_req_task_submit(req, tw);
+			io_req_task_submit(tw_req, tw);
 		else
 			io_req_defer_failed(req, ret);
 	}

io_uring/poll.h

···
 bool io_poll_remove_all(struct io_ring_ctx *ctx, struct io_uring_task *tctx,
 			bool cancel_all);
 
-void io_poll_task_func(struct io_kiocb *req, io_tw_token_t tw);
+void io_poll_task_func(struct io_tw_req tw_req, io_tw_token_t tw);

io_uring/rw.c

···
 	return res;
 }
 
-void io_req_rw_complete(struct io_kiocb *req, io_tw_token_t tw)
+void io_req_rw_complete(struct io_tw_req tw_req, io_tw_token_t tw)
 {
+	struct io_kiocb *req = tw_req.req;
 	struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
 	struct kiocb *kiocb = &rw->kiocb;
 
···
 		req->cqe.flags |= io_put_kbuf(req, req->cqe.res, NULL);
 
 	io_req_rw_cleanup(req, 0);
-	io_req_task_complete(req, tw);
+	io_req_task_complete(tw_req, tw);
 }
 
 static void io_complete_rw(struct kiocb *kiocb, long res)

io_uring/rw.h

···
 int io_write_fixed(struct io_kiocb *req, unsigned int issue_flags);
 void io_readv_writev_cleanup(struct io_kiocb *req);
 void io_rw_fail(struct io_kiocb *req);
-void io_req_rw_complete(struct io_kiocb *req, io_tw_token_t tw);
+void io_req_rw_complete(struct io_tw_req tw_req, io_tw_token_t tw);
 int io_read_mshot_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
 int io_read_mshot(struct io_kiocb *req, unsigned int issue_flags);
 void io_rw_cache_free(const void *entry);

io_uring/timeout.c

···
 
 static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer);
 
-static void io_timeout_complete(struct io_kiocb *req, io_tw_token_t tw)
+static void io_timeout_complete(struct io_tw_req tw_req, io_tw_token_t tw)
 {
+	struct io_kiocb *req = tw_req.req;
 	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
 	struct io_timeout_data *data = req->async_data;
 	struct io_ring_ctx *ctx = req->ctx;
···
 		}
 	}
 
-	io_req_task_complete(req, tw);
+	io_req_task_complete(tw_req, tw);
 }
 
 static __cold bool io_flush_killed_timeouts(struct list_head *list, int err)
···
 	io_flush_killed_timeouts(&list, 0);
 }
 
-static void io_req_tw_fail_links(struct io_kiocb *link, io_tw_token_t tw)
+static void io_req_tw_fail_links(struct io_tw_req tw_req, io_tw_token_t tw)
 {
+	struct io_kiocb *link = tw_req.req;
+
 	io_tw_lock(link->ctx, tw);
 	while (link) {
 		struct io_kiocb *nxt = link->link;
···
 			res = link->cqe.res;
 		link->link = NULL;
 		io_req_set_res(link, res, 0);
-		io_req_task_complete(link, tw);
+		io_req_task_complete((struct io_tw_req){link}, tw);
 		link = nxt;
 	}
 }
···
 	return 0;
 }
 
-static void io_req_task_link_timeout(struct io_kiocb *req, io_tw_token_t tw)
+static void io_req_task_link_timeout(struct io_tw_req tw_req, io_tw_token_t tw)
 {
+	struct io_kiocb *req = tw_req.req;
 	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
 	struct io_kiocb *prev = timeout->prev;
 	int ret;
···
 			ret = -ECANCELED;
 		}
 		io_req_set_res(req, ret ?: -ETIME, 0);
-		io_req_task_complete(req, tw);
+		io_req_task_complete(tw_req, tw);
 		io_put_req(prev);
 	} else {
 		io_req_set_res(req, -ETIME, 0);
-		io_req_task_complete(req, tw);
+		io_req_task_complete(tw_req, tw);
 	}
 }
 

io_uring/uring_cmd.c

···
 }
 EXPORT_SYMBOL_GPL(io_uring_cmd_mark_cancelable);
 
-static void io_uring_cmd_work(struct io_kiocb *req, io_tw_token_t tw)
+static void io_uring_cmd_work(struct io_tw_req tw_req, io_tw_token_t tw)
 {
+	struct io_kiocb *req = tw_req.req;
 	struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
 	unsigned int flags = IO_URING_F_COMPLETE_DEFER;
 

io_uring/waitid.c

···
 #include "waitid.h"
 #include "../kernel/exit.h"
 
-static void io_waitid_cb(struct io_kiocb *req, io_tw_token_t tw);
+static void io_waitid_cb(struct io_tw_req tw_req, io_tw_token_t tw);
 
 #define IO_WAITID_CANCEL_FLAG	BIT(31)
 #define IO_WAITID_REF_MASK	GENMASK(30, 0)
···
 	return true;
 }
 
-static void io_waitid_cb(struct io_kiocb *req, io_tw_token_t tw)
+static void io_waitid_cb(struct io_tw_req tw_req, io_tw_token_t tw)
 {
+	struct io_kiocb *req = tw_req.req;
 	struct io_waitid_async *iwa = req->async_data;
 	struct io_ring_ctx *ctx = req->ctx;
 	int ret;
···
 	}
 
 	io_waitid_complete(req, ret);
-	io_req_task_complete(req, tw);
+	io_req_task_complete(tw_req, tw);
 }
 
 static int io_waitid_wait(struct wait_queue_entry *wait, unsigned mode,