Revert "Revert "io_uring: Use io_schedule* in cqring wait""

This reverts commit 992f4fa.

Author: popcornmix

io_uring/io_uring.c

@@ -2354,7 +2354,7 @@ static inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx,
 					  struct io_wait_queue *iowq,
 					  ktime_t *timeout)
 {
-	int ret;
+	int token, ret;
 	unsigned long check_cq;
 
 	/* make sure we run task_work before checking for signals */
@@ -2370,9 +2370,18 @@ static inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx,
 		if (check_cq & BIT(IO_CHECK_CQ_DROPPED_BIT))
 			return -EBADR;
 	}
+
+	/*
+	 * Use io_schedule_prepare/finish, so cpufreq can take into account
+	 * that the task is waiting for IO - turns out to be important for low
+	 * QD IO.
+	 */
+	token = io_schedule_prepare();
+	ret = 1;
 	if (!schedule_hrtimeout(timeout, HRTIMER_MODE_ABS))
-		return -ETIME;
-	return 1;
+		ret = -ETIME;
+	io_schedule_finish(token);
+	return ret;
 }
 
 /*