diff options
| author | Tejun Heo <tj@kernel.org> | 2013-05-14 13:52:31 -0700 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2013-05-14 13:52:31 -0700 |
| commit | db61367038dcd222476881cb09fd54661b3cd508 (patch) | |
| tree | 2c13a848bc64d34175ab7abbd0774b816a41f20e | |
| parent | aa539cb38f4f1365ad52fed6a857b25f8b4dc06c (diff) | |
blkcg: invoke blkcg_policy->pd_init() after parent is linked
Currently, when creating a new blkcg_gq, each policy's pd_init_fn() is
invoked in blkg_alloc() before the parent is linked. This makes it
difficult for policies to perform initializations which are dependent
on the parent.
This patch moves pd_init_fn() invocations to blkg_create() after the
parent blkg is linked where the new blkg is fully initialized. As
this means that blkg_free() can't assume that pd's are initialized,
pd_exit_fn() invocations are moved to __blkg_release(). This
guarantees that pd_exit_fn() is also invoked with fully initialized
blkgs with valid parent pointers.
This will help implementing hierarchy support in blk-throttle.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
| -rw-r--r-- | block/blk-cgroup.c | 39 |
1 files changed, 22 insertions, 17 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index b950306838a..6bbe0a93959 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -51,18 +51,8 @@ static void blkg_free(struct blkcg_gq *blkg) if (!blkg) return; - for (i = 0; i < BLKCG_MAX_POLS; i++) { - struct blkcg_policy *pol = blkcg_policy[i]; - struct blkg_policy_data *pd = blkg->pd[i]; - - if (!pd) - continue; - - if (pol && pol->pd_exit_fn) - pol->pd_exit_fn(blkg); - - kfree(pd); - } + for (i = 0; i < BLKCG_MAX_POLS; i++) + kfree(blkg->pd[i]); blk_exit_rl(&blkg->rl); kfree(blkg); @@ -114,10 +104,6 @@ static struct blkcg_gq *blkg_alloc(struct blkcg *blkcg, struct request_queue *q, blkg->pd[i] = pd; pd->blkg = blkg; pd->plid = i; - - /* invoke per-policy init */ - if (pol->pd_init_fn) - pol->pd_init_fn(blkg); } return blkg; @@ -214,7 +200,7 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg, } blkg = new_blkg; - /* link parent and insert */ + /* link parent */ if (blkcg_parent(blkcg)) { blkg->parent = __blkg_lookup(blkcg_parent(blkcg), q, false); if (WARN_ON_ONCE(!blkg->parent)) { @@ -224,6 +210,15 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg, blkg_get(blkg->parent); } + /* invoke per-policy init */ + for (i = 0; i < BLKCG_MAX_POLS; i++) { + struct blkcg_policy *pol = blkcg_policy[i]; + + if (blkg->pd[i] && pol->pd_init_fn) + pol->pd_init_fn(blkg); + } + + /* insert */ spin_lock(&blkcg->lock); ret = radix_tree_insert(&blkcg->blkg_tree, q->id, blkg); if (likely(!ret)) { @@ -381,6 +376,16 @@ static void blkg_rcu_free(struct rcu_head *rcu_head) void __blkg_release(struct blkcg_gq *blkg) { + int i; + + /* tell policies that this one is being freed */ + for (i = 0; i < BLKCG_MAX_POLS; i++) { + struct blkcg_policy *pol = blkcg_policy[i]; + + if (blkg->pd[i] && pol->pd_exit_fn) + pol->pd_exit_fn(blkg); + } + /* release the blkcg and parent blkg refs this blkg has been holding */ css_put(&blkg->blkcg->css); if (blkg->parent) |