iocost: fix a deadlock in ioc_rqos_throttle()

hulk inclusion
category: feature
bugzilla: 38688
CVE: NA

---------------------------

ioc_rqos_throttle() may called inside queue_lock, the lock should
be unlocked before sleep.
Signed-off-by: NJiufei Xue <jiufei.xue@linux.alibaba.com>
Reviewed-by: NJoseph Qi <joseph.qi@linux.alibaba.com>

Conflict: block/blk-iocost.c
Signed-off-by: NYu Kuai <yukuai3@huawei.com>
Reviewed-by: NHou Tao <houtao1@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

block/blk-iocost.c

@@ -1678,6 +1678,8 @@ static u64 calc_vtime_cost(struct bio *bio, struct ioc_gq *iocg, bool is_merge)
 
 static void ioc_rqos_throttle(struct rq_qos *rqos, struct bio *bio,
 		spinlock_t *lock)
+	__releases(lock)
+	__acquires(lock)
 {
 	struct ioc *ioc = rqos_to_ioc(rqos);
 	struct request_queue *q = rqos->q;
@@ -1814,8 +1816,15 @@ static void ioc_rqos_throttle(struct rq_qos *rqos, struct bio *bio,
 		set_current_state(TASK_UNINTERRUPTIBLE);
 		if (wait.committed)
 			break;
+
+		if (lock) {
+			spin_unlock_irq(lock);
+			io_schedule();
+			spin_lock_irq(lock);
+		} else {
 			io_schedule();
 		}
+	}
 
 	/* waker already committed us, proceed */
 	finish_wait(&iocg->waitq, &wait.wait);