io_uring: make io_cqring_events() take 'ctx' as argument

The rings can be derived from the ctx, and we need the ctx there for
a future change.

No functional changes in this patch.
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -866,8 +866,10 @@ static void io_put_req(struct io_kiocb *req, struct io_kiocb **nxtptr)
 	}
 }
 
-static unsigned io_cqring_events(struct io_rings *rings)
+static unsigned io_cqring_events(struct io_ring_ctx *ctx)
 {
+	struct io_rings *rings = ctx->rings;
+
 	/* See comment at the top of this file */
 	smp_rmb();
 	return READ_ONCE(rings->cq.tail) - READ_ONCE(rings->cq.head);
@@ -1023,7 +1025,7 @@ static int __io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events,
 		 * If we do, we can potentially be spinning for commands that
 		 * already triggered a CQE (eg in error).
 		 */
-		if (io_cqring_events(ctx->rings))
+		if (io_cqring_events(ctx))
 			break;
 
 		/*
@@ -3076,7 +3078,7 @@ static inline bool io_should_wake(struct io_wait_queue *iowq)
 	 * started waiting. For timeouts, we always want to return to userspace,
 	 * regardless of event count.
 	 */
-	return io_cqring_events(ctx->rings) >= iowq->to_wait ||
+	return io_cqring_events(ctx) >= iowq->to_wait ||
 			atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts;
 }
 
@@ -3111,7 +3113,7 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
 	struct io_rings *rings = ctx->rings;
 	int ret = 0;
 
-	if (io_cqring_events(rings) >= min_events)
+	if (io_cqring_events(ctx) >= min_events)
 		return 0;
 
 	if (sig) {