diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index c5dc833212e1..0a63c6cbbcb1 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -1530,6 +1530,10 @@ static void blkcg_scale_delay(struct blkcg_gq *blkg, u64 now)
 {
 	u64 old = atomic64_read(&blkg->delay_start);
 
+	/* negative use_delay means no scaling, see blkcg_set_delay() */
+	if (atomic_read(&blkg->use_delay) < 0)
+		return;
+
 	/*
 	 * We only want to scale down every second.  The idea here is that we
 	 * want to delay people for min(delay_nsec, NSEC_PER_SEC) in a certain
@@ -1717,6 +1721,8 @@ void blkcg_schedule_throttle(struct request_queue *q, bool use_memdelay)
  */
 void blkcg_add_delay(struct blkcg_gq *blkg, u64 now, u64 delta)
 {
+	if (WARN_ON_ONCE(atomic_read(&blkg->use_delay) < 0))
+		return;
 	blkcg_scale_delay(blkg, now);
 	atomic64_add(delta, &blkg->delay_nsec);
 }
diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index db35ee682294..a8e99ef76a08 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -1209,14 +1209,14 @@ static enum hrtimer_restart iocg_waitq_timer_fn(struct hrtimer *timer)
 	return HRTIMER_NORESTART;
 }
 
-static bool iocg_kick_delay(struct ioc_gq *iocg, struct ioc_now *now, u64 cost)
+static bool iocg_kick_delay(struct ioc_gq *iocg, struct ioc_now *now)
 {
 	struct ioc *ioc = iocg->ioc;
 	struct blkcg_gq *blkg = iocg_to_blkg(iocg);
 	u64 vtime = atomic64_read(&iocg->vtime);
 	u64 vmargin = ioc->margin_us * now->vrate;
 	u64 margin_ns = ioc->margin_us * NSEC_PER_USEC;
-	u64 expires, oexpires;
+	u64 delta_ns, expires, oexpires;
 	u32 hw_inuse;
 
 	/* debt-adjust vtime */
@@ -1233,15 +1233,10 @@ static bool iocg_kick_delay(struct ioc_gq *iocg, struct ioc_now *now, u64 cost)
 		return false;
 
 	/* use delay */
-	if (cost) {
-		u64 cost_ns = DIV64_U64_ROUND_UP(cost * NSEC_PER_USEC,
-						 now->vrate);
-		blkcg_add_delay(blkg, now->now_ns, cost_ns);
-	}
-	blkcg_use_delay(blkg);
-
-	expires = now->now_ns + DIV64_U64_ROUND_UP(vtime - now->vnow,
-						   now->vrate) * NSEC_PER_USEC;
+	delta_ns = DIV64_U64_ROUND_UP(vtime - now->vnow,
+				      now->vrate) * NSEC_PER_USEC;
+	blkcg_set_delay(blkg, delta_ns);
+	expires = now->now_ns + delta_ns;
 
 	/* if already active and close enough, don't bother */
 	oexpires = ktime_to_ns(hrtimer_get_softexpires(&iocg->delay_timer));
@@ -1260,7 +1255,7 @@ static enum hrtimer_restart iocg_delay_timer_fn(struct hrtimer *timer)
 	struct ioc_now now;
 
 	ioc_now(iocg->ioc, &now);
-	iocg_kick_delay(iocg, &now, 0);
+	iocg_kick_delay(iocg, &now);
 
 	return HRTIMER_NORESTART;
 }
@@ -1378,7 +1373,7 @@ static void ioc_timer_fn(struct timer_list *timer)
 		    atomic64_read(&iocg->abs_vdebt)) {
 			/* might be oversleeping vtime / hweight changes, kick */
 			iocg_kick_waitq(iocg, &now);
-			iocg_kick_delay(iocg, &now, 0);
+			iocg_kick_delay(iocg, &now);
 		} else if (iocg_is_idle(iocg)) {
 			/* no waiter and idle, deactivate */
 			iocg->last_inuse = iocg->inuse;
@@ -1737,7 +1732,7 @@ static void ioc_rqos_throttle(struct rq_qos *rqos, struct bio *bio)
 	 */
 	if (bio_issue_as_root_blkg(bio) || fatal_signal_pending(current)) {
 		atomic64_add(abs_cost, &iocg->abs_vdebt);
-		if (iocg_kick_delay(iocg, &now, cost))
+		if (iocg_kick_delay(iocg, &now))
 			blkcg_schedule_throttle(rqos->q,
 					(bio->bi_opf & REQ_SWAP) == REQ_SWAP);
 		return;
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index 4deb8bb7b6af..a57ebe2f00ab 100644
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -631,6 +631,8 @@ static inline bool blkcg_bio_issue_check(struct request_queue *q,
 
 static inline void blkcg_use_delay(struct blkcg_gq *blkg)
 {
+	if (WARN_ON_ONCE(atomic_read(&blkg->use_delay) < 0))
+		return;
 	if (atomic_add_return(1, &blkg->use_delay) == 1)
 		atomic_inc(&blkg->blkcg->css.cgroup->congestion_count);
 }
@@ -639,6 +641,8 @@ static inline int blkcg_unuse_delay(struct blkcg_gq *blkg)
 {
 	int old = atomic_read(&blkg->use_delay);
 
+	if (WARN_ON_ONCE(old < 0))
+		return 0;
 	if (old == 0)
 		return 0;
 
@@ -663,20 +667,39 @@ static inline int blkcg_unuse_delay(struct blkcg_gq *blkg)
 	return 1;
 }
 
+/**
+ * blkcg_set_delay - Enable allocator delay mechanism with the specified delay amount
+ * @blkg: target blkg
+ * @delay: delay duration in nsecs
+ *
+ * When enabled with this function, the delay is not decayed and must be
+ * explicitly cleared with blkcg_clear_delay(). Must not be mixed with
+ * blkcg_[un]use_delay() and blkcg_add_delay() usages.
+ */
+static inline void blkcg_set_delay(struct blkcg_gq *blkg, u64 delay)
+{
+	int old = atomic_read(&blkg->use_delay);
+
+	/* We only want 1 person setting the congestion count for this blkg. */
+	if (!old && atomic_cmpxchg(&blkg->use_delay, old, -1) == old)
+		atomic_inc(&blkg->blkcg->css.cgroup->congestion_count);
+
+	atomic64_set(&blkg->delay_nsec, delay);
+}
+
+/**
+ * blkcg_clear_delay - Disable allocator delay mechanism
+ * @blkg: target blkg
+ *
+ * Disable use_delay mechanism. See blkcg_set_delay().
+ */
 static inline void blkcg_clear_delay(struct blkcg_gq *blkg)
 {
 	int old = atomic_read(&blkg->use_delay);
-	if (!old)
-		return;
+
 	/* We only want 1 person clearing the congestion count for this blkg. */
-	while (old) {
-		int cur = atomic_cmpxchg(&blkg->use_delay, old, 0);
-		if (cur == old) {
-			atomic_dec(&blkg->blkcg->css.cgroup->congestion_count);
-			break;
-		}
-		old = cur;
-	}
+	if (old && atomic_cmpxchg(&blkg->use_delay, old, 0) == old)
+		atomic_dec(&blkg->blkcg->css.cgroup->congestion_count);
 }
 
 void blkcg_add_delay(struct blkcg_gq *blkg, u64 now, u64 delta);