diff options
Diffstat (limited to 'block/blk-rq-qos.h')
| -rw-r--r-- | block/blk-rq-qos.h | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/block/blk-rq-qos.h b/block/blk-rq-qos.h index 2bc43e94f4c4..2bcb3495e376 100644 --- a/block/blk-rq-qos.h +++ b/block/blk-rq-qos.h @@ -7,6 +7,7 @@ #include <linux/blk_types.h> #include <linux/atomic.h> #include <linux/wait.h> +#include <linux/blk-mq.h> #include "blk-mq-debugfs.h" @@ -99,8 +100,21 @@ static inline void rq_wait_init(struct rq_wait *rq_wait) static inline void 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); 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) blk_mq_debugfs_register_rqos(rqos); @@ -110,12 +124,22 @@ 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); blk_mq_debugfs_unregister_rqos(rqos); } |