io_uring: use typesafe pointers in io_uring_task

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Link: https://lore.kernel.org/r/ce2a598e66e48347bb04afbaf2acc67c0cc7971a.1615809009.git.metze@samba.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -460,8 +460,8 @@ struct io_uring_task {
 	/* submission side */
 	struct xarray		xa;
 	struct wait_queue_head	wait;
-	void			*last;
-	void			*io_wq;
+	const struct io_ring_ctx *last;
+	struct io_wq		*io_wq;
 	struct percpu_counter	inflight;
 	atomic_t		in_idle;
 	bool			sqpoll;