1 files changed, 40 insertions, 76 deletions

diff --git a/block/blk-rq-qos.h b/block/blk-rq-qos.h
index 1ef1f7d4bc3c..b538f2c0febc 100644
--- a/block/blk-rq-qos.h
+++ b/block/blk-rq-qos.h
@@ -25,8 +25,8 @@ struct rq_wait {
 };
 
 struct rq_qos {
-	struct rq_qos_ops *ops;
-	struct request_queue *q;
+	const struct rq_qos_ops *ops;
+	struct gendisk *disk;
 	enum rq_qos_id id;
 	struct rq_qos *next;
 #ifdef CONFIG_BLK_DEBUG_FS
@@ -74,7 +74,7 @@ static inline struct rq_qos *wbt_rq_qos(struct request_queue *q)
 	return rq_qos_id(q, RQ_QOS_WBT);
 }
 
-static inline struct rq_qos *blkcg_rq_qos(struct request_queue *q)
+static inline struct rq_qos *iolat_rq_qos(struct request_queue *q)
 {
 	return rq_qos_id(q, RQ_QOS_LATENCY);
 }
@@ -85,65 +85,9 @@ static inline void rq_wait_init(struct rq_wait *rq_wait)
 	init_waitqueue_head(&rq_wait->wait);
 }
 
-static inline int rq_qos_add(struct request_queue *q, struct rq_qos *rqos)
-{
-	/*
-	 * No IO can be in-flight when adding rqos, so freeze queue, which
-	 * is fine since we only support rq_qos for blk-mq queue.
-	 *
-	 * Reuse ->queue_lock for protecting against other concurrent
-	 * rq_qos adding/deleting
-	 */
-	blk_mq_freeze_queue(q);
-
-	spin_lock_irq(&q->queue_lock);
-	if (rq_qos_id(q, rqos->id))
-		goto ebusy;
-	rqos->next = q->rq_qos;
-	q->rq_qos = rqos;
-	spin_unlock_irq(&q->queue_lock);
-
-	blk_mq_unfreeze_queue(q);
-
-	if (rqos->ops->debugfs_attrs) {
-		mutex_lock(&q->debugfs_mutex);
-		blk_mq_debugfs_register_rqos(rqos);
-		mutex_unlock(&q->debugfs_mutex);
-	}
-
-	return 0;
-ebusy:
-	spin_unlock_irq(&q->queue_lock);
-	blk_mq_unfreeze_queue(q);
-	return -EBUSY;
-
-}
-
-static inline void rq_qos_del(struct request_queue *q, struct rq_qos *rqos)
-{
-	struct rq_qos **cur;
-
-	/*
-	 * See comment in rq_qos_add() about freezing queue & using
-	 * ->queue_lock.
-	 */
-	blk_mq_freeze_queue(q);
-
-	spin_lock_irq(&q->queue_lock);
-	for (cur = &q->rq_qos; *cur; cur = &(*cur)->next) {
-		if (*cur == rqos) {
-			*cur = rqos->next;
-			break;
-		}
-	}
-	spin_unlock_irq(&q->queue_lock);
-
-	blk_mq_unfreeze_queue(q);
-
-	mutex_lock(&q->debugfs_mutex);
-	blk_mq_debugfs_unregister_rqos(rqos);
-	mutex_unlock(&q->debugfs_mutex);
-}
+int rq_qos_add(struct rq_qos *rqos, struct gendisk *disk, enum rq_qos_id id,
+		const struct rq_qos_ops *ops);
+void rq_qos_del(struct rq_qos *rqos);
 
 typedef bool (acquire_inflight_cb_t)(struct rq_wait *rqw, void *private_data);
 typedef void (cleanup_cb_t)(struct rq_wait *rqw, void *private_data);
@@ -168,41 +112,58 @@ void __rq_qos_queue_depth_changed(struct rq_qos *rqos);
 
 static inline void rq_qos_cleanup(struct request_queue *q, struct bio *bio)
 {
-	if (q->rq_qos)
+	if (unlikely(test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags)) &&
+			q->rq_qos)
 		__rq_qos_cleanup(q->rq_qos, bio);
 }
 
 static inline void rq_qos_done(struct request_queue *q, struct request *rq)
 {
-	if (q->rq_qos)
+	if (unlikely(test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags)) &&
+			q->rq_qos && !blk_rq_is_passthrough(rq))
 		__rq_qos_done(q->rq_qos, rq);
 }
 
 static inline void rq_qos_issue(struct request_queue *q, struct request *rq)
 {
-	if (q->rq_qos)
+	if (unlikely(test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags)) &&
+			q->rq_qos)
 		__rq_qos_issue(q->rq_qos, rq);
 }
 
 static inline void rq_qos_requeue(struct request_queue *q, struct request *rq)
 {
-	if (q->rq_qos)
+	if (unlikely(test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags)) &&
+			q->rq_qos)
 		__rq_qos_requeue(q->rq_qos, rq);
 }
 
 static inline void rq_qos_done_bio(struct bio *bio)
 {
-	if (bio->bi_bdev && (bio_flagged(bio, BIO_QOS_THROTTLED) ||
-			     bio_flagged(bio, BIO_QOS_MERGED))) {
-		struct request_queue *q = bdev_get_queue(bio->bi_bdev);
-		if (q->rq_qos)
-			__rq_qos_done_bio(q->rq_qos, bio);
-	}
+	struct request_queue *q;
+
+	if (!bio->bi_bdev || (!bio_flagged(bio, BIO_QOS_THROTTLED) &&
+			     !bio_flagged(bio, BIO_QOS_MERGED)))
+		return;
+
+	q = bdev_get_queue(bio->bi_bdev);
+
+	/*
+	 * A BIO may carry BIO_QOS_* flags even if the associated request_queue
+	 * does not have rq_qos enabled. This can happen with stacked block
+	 * devices — for example, NVMe multipath, where it's possible that the
+	 * bottom device has QoS enabled but the top device does not. Therefore,
+	 * always verify that q->rq_qos is present and QoS is enabled before
+	 * calling __rq_qos_done_bio().
+	 */
+	if (test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags) && q->rq_qos)
+		__rq_qos_done_bio(q->rq_qos, bio);
 }
 
 static inline void rq_qos_throttle(struct request_queue *q, struct bio *bio)
 {
-	if (q->rq_qos) {
+	if (unlikely(test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags)) &&
+			q->rq_qos) {
 		bio_set_flag(bio, BIO_QOS_THROTTLED);
 		__rq_qos_throttle(q->rq_qos, bio);
 	}
@@ -211,14 +172,16 @@ static inline void rq_qos_throttle(struct request_queue *q, struct bio *bio)
 static inline void rq_qos_track(struct request_queue *q, struct request *rq,
 				struct bio *bio)
 {
-	if (q->rq_qos)
+	if (unlikely(test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags)) &&
+			q->rq_qos)
 		__rq_qos_track(q->rq_qos, rq, bio);
 }
 
 static inline void rq_qos_merge(struct request_queue *q, struct request *rq,
 				struct bio *bio)
 {
-	if (q->rq_qos) {
+	if (unlikely(test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags)) &&
+			q->rq_qos) {
 		bio_set_flag(bio, BIO_QOS_MERGED);
 		__rq_qos_merge(q->rq_qos, rq, bio);
 	}
@@ -226,7 +189,8 @@ static inline void rq_qos_merge(struct request_queue *q, struct request *rq,
 
 static inline void rq_qos_queue_depth_changed(struct request_queue *q)
 {
-	if (q->rq_qos)
+	if (unlikely(test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags)) &&
+			q->rq_qos)
 		__rq_qos_queue_depth_changed(q->rq_qos);
 }