diff options
| -rw-r--r-- | block/blk-cgroup.c | 35 | ||||
| -rw-r--r-- | include/linux/blkdev.h | 1 |
2 files changed, 30 insertions, 6 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 75f3c4460715..cb110fc51940 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -118,16 +118,32 @@ static void blkg_free_workfn(struct work_struct *work) { struct blkcg_gq *blkg = container_of(work, struct blkcg_gq, free_work); + struct request_queue *q = blkg->q; int i; + /* + * pd_free_fn() can also be called from blkcg_deactivate_policy(), + * in order to make sure pd_free_fn() is called in order, the deletion + * of the list blkg->q_node is delayed to here from blkg_destroy(), and + * blkcg_mutex is used to synchronize blkg_free_workfn() and + * blkcg_deactivate_policy(). + */ + if (q) + mutex_lock(&q->blkcg_mutex); + for (i = 0; i < BLKCG_MAX_POLS; i++) if (blkg->pd[i]) blkcg_policy[i]->pd_free_fn(blkg->pd[i]); if (blkg->parent) blkg_put(blkg->parent); - if (blkg->q) - blk_put_queue(blkg->q); + + if (q) { + list_del_init(&blkg->q_node); + mutex_unlock(&q->blkcg_mutex); + blk_put_queue(q); + } + free_percpu(blkg->iostat_cpu); percpu_ref_exit(&blkg->refcnt); kfree(blkg); @@ -462,9 +478,14 @@ static void blkg_destroy(struct blkcg_gq *blkg) lockdep_assert_held(&blkg->q->queue_lock); lockdep_assert_held(&blkcg->lock); - /* Something wrong if we are trying to remove same group twice */ - WARN_ON_ONCE(list_empty(&blkg->q_node)); - WARN_ON_ONCE(hlist_unhashed(&blkg->blkcg_node)); + /* + * blkg stays on the queue list until blkg_free_workfn(), see details in + * blkg_free_workfn(), hence this function can be called from + * blkcg_destroy_blkgs() first and again from blkg_destroy_all() before + * blkg_free_workfn(). + */ + if (hlist_unhashed(&blkg->blkcg_node)) + return; for (i = 0; i < BLKCG_MAX_POLS; i++) { struct blkcg_policy *pol = blkcg_policy[i]; @@ -479,7 +500,6 @@ static void blkg_destroy(struct blkcg_gq *blkg) blkg->online = false; radix_tree_delete(&blkcg->blkg_tree, blkg->q->id); - list_del_init(&blkg->q_node); hlist_del_init_rcu(&blkg->blkcg_node); /* @@ -1280,6 +1300,7 @@ int blkcg_init_disk(struct gendisk *disk) int ret; INIT_LIST_HEAD(&q->blkg_list); + mutex_init(&q->blkcg_mutex); new_blkg = blkg_alloc(&blkcg_root, disk, GFP_KERNEL); if (!new_blkg) @@ -1520,6 +1541,7 @@ void blkcg_deactivate_policy(struct request_queue *q, if (queue_is_mq(q)) blk_mq_freeze_queue(q); + mutex_lock(&q->blkcg_mutex); spin_lock_irq(&q->queue_lock); __clear_bit(pol->plid, q->blkcg_pols); @@ -1538,6 +1560,7 @@ void blkcg_deactivate_policy(struct request_queue *q, } spin_unlock_irq(&q->queue_lock); + mutex_unlock(&q->blkcg_mutex); if (queue_is_mq(q)) blk_mq_unfreeze_queue(q); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 89f51d68c68a..b9637d63e6f0 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -485,6 +485,7 @@ struct request_queue { DECLARE_BITMAP (blkcg_pols, BLKCG_MAX_POLS); struct blkcg_gq *root_blkg; struct list_head blkg_list; + struct mutex blkcg_mutex; #endif struct queue_limits limits; |