diff options
| -rw-r--r-- | block/blk-cgroup.c | 34 | ||||
| -rw-r--r-- | block/blk-cgroup.h | 4 |
2 files changed, 18 insertions, 20 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 6bbe0a9..d074760 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -369,13 +369,17 @@ static void blkg_destroy_all(struct request_queue *q) q->root_rl.blkg = NULL; } -static void blkg_rcu_free(struct rcu_head *rcu_head) -{ - blkg_free(container_of(rcu_head, struct blkcg_gq, rcu_head)); -} - -void __blkg_release(struct blkcg_gq *blkg) +/* + * A group is RCU protected, but having an rcu lock does not mean that one + * can access all the fields of blkg and assume these are valid. For + * example, don't try to follow throtl_data and request queue links. + * + * Having a reference to blkg under an rcu allows accesses to only values + * local to groups like group stats and group rate limits. + */ +void __blkg_release_rcu(struct rcu_head *rcu_head) { + struct blkcg_gq *blkg = container_of(rcu_head, struct blkcg_gq, rcu_head); int i; /* tell policies that this one is being freed */ @@ -388,21 +392,15 @@ void __blkg_release(struct blkcg_gq *blkg) /* release the blkcg and parent blkg refs this blkg has been holding */ css_put(&blkg->blkcg->css); - if (blkg->parent) + if (blkg->parent) { + spin_lock_irq(blkg->q->queue_lock); blkg_put(blkg->parent); + spin_unlock_irq(blkg->q->queue_lock); + } - /* - * A group is freed in rcu manner. But having an rcu lock does not - * mean that one can access all the fields of blkg and assume these - * are valid. For example, don't try to follow throtl_data and - * request queue links. - * - * Having a reference to blkg under an rcu allows acess to only - * values local to groups like group stats and group rate limits - */ - call_rcu(&blkg->rcu_head, blkg_rcu_free); + blkg_free(blkg); } -EXPORT_SYMBOL_GPL(__blkg_release); +EXPORT_SYMBOL_GPL(__blkg_release_rcu); /* * The next function used by blk_queue_for_each_rl(). It's a bit tricky diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h index e15f731..8056c03 100644 --- a/block/blk-cgroup.h +++ b/block/blk-cgroup.h @@ -266,7 +266,7 @@ static inline void blkg_get(struct blkcg_gq *blkg) blkg->refcnt++; } -void __blkg_release(struct blkcg_gq *blkg); +void __blkg_release_rcu(struct rcu_head *rcu); /** * blkg_put - put a blkg reference @@ -279,7 +279,7 @@ static inline void blkg_put(struct blkcg_gq *blkg) lockdep_assert_held(blkg->q->queue_lock); WARN_ON_ONCE(blkg->refcnt <= 0); if (!--blkg->refcnt) - __blkg_release(blkg); + call_rcu(&blkg->rcu_head, __blkg_release_rcu); } struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg, struct request_queue *q, |
