1 files changed, 11 insertions, 24 deletions

diff --git a/block/blk-wbt.c b/block/blk-wbt.c
index e49a48684532..0bb613139bec 100644
--- a/block/blk-wbt.c
+++ b/block/blk-wbt.c
@@ -146,7 +146,7 @@ enum {
 static inline bool rwb_enabled(struct rq_wb *rwb)
 {
 	return rwb && rwb->enable_state != WBT_STATE_OFF_DEFAULT &&
-		      rwb->wb_normal != 0;
+		      rwb->enable_state != WBT_STATE_OFF_MANUAL;
 }
 
 static void wb_timestamp(struct rq_wb *rwb, unsigned long *var)
@@ -201,15 +201,6 @@ static void wbt_rqw_done(struct rq_wb *rwb, struct rq_wait *rqw,
 	inflight = atomic_dec_return(&rqw->inflight);
 
 	/*
-	 * wbt got disabled with IO in flight. Wake up any potential
-	 * waiters, we don't have to do more than that.
-	 */
-	if (unlikely(!rwb_enabled(rwb))) {
-		rwb_wake_all(rwb);
-		return;
-	}
-
-	/*
 	 * For discards, our limit is always the background. For writes, if
 	 * the device does write back caching, drop further down before we
 	 * wake people up.
@@ -503,8 +494,7 @@ bool wbt_disabled(struct request_queue *q)
 {
 	struct rq_qos *rqos = wbt_rq_qos(q);
 
-	return !rqos || RQWB(rqos)->enable_state == WBT_STATE_OFF_DEFAULT ||
-	       RQWB(rqos)->enable_state == WBT_STATE_OFF_MANUAL;
+	return !rqos || !rwb_enabled(RQWB(rqos));
 }
 
 u64 wbt_get_min_lat(struct request_queue *q)
@@ -545,13 +535,6 @@ static inline unsigned int get_limit(struct rq_wb *rwb, blk_opf_t opf)
 {
 	unsigned int limit;
 
-	/*
-	 * If we got disabled, just return UINT_MAX. This ensures that
-	 * we'll properly inc a new IO, and dec+wakeup at the end.
-	 */
-	if (!rwb_enabled(rwb))
-		return UINT_MAX;
-
 	if ((opf & REQ_OP_MASK) == REQ_OP_DISCARD)
 		return rwb->wb_background;
 
@@ -730,14 +713,16 @@ void wbt_enable_default(struct gendisk *disk)
 {
 	struct request_queue *q = disk->queue;
 	struct rq_qos *rqos;
-	bool disable_flag = q->elevator &&
-		    test_bit(ELEVATOR_FLAG_DISABLE_WBT, &q->elevator->flags);
+	bool enable = IS_ENABLED(CONFIG_BLK_WBT_MQ);
+
+	if (q->elevator &&
+	    test_bit(ELEVATOR_FLAG_DISABLE_WBT, &q->elevator->flags))
+		enable = false;
 
 	/* Throttling already enabled? */
 	rqos = wbt_rq_qos(q);
 	if (rqos) {
-		if (!disable_flag &&
-		    RQWB(rqos)->enable_state == WBT_STATE_OFF_DEFAULT)
+		if (enable && RQWB(rqos)->enable_state == WBT_STATE_OFF_DEFAULT)
 			RQWB(rqos)->enable_state = WBT_STATE_ON_DEFAULT;
 		return;
 	}
@@ -746,7 +731,7 @@ void wbt_enable_default(struct gendisk *disk)
 	if (!blk_queue_registered(q))
 		return;
 
-	if (queue_is_mq(q) && !disable_flag)
+	if (queue_is_mq(q) && enable)
 		wbt_init(disk);
 }
 EXPORT_SYMBOL_GPL(wbt_enable_default);
@@ -942,7 +927,9 @@ int wbt_init(struct gendisk *disk)
 	/*
 	 * Assign rwb and add the stats callback.
 	 */
+	mutex_lock(&q->rq_qos_mutex);
 	ret = rq_qos_add(&rwb->rqos, disk, RQ_QOS_WBT, &wbt_rqos_ops);
+	mutex_unlock(&q->rq_qos_mutex);
 	if (ret)
 		goto err_free;