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authorTejun Heo <tj@kernel.org>2013-05-14 13:52:31 -0700
committerTejun Heo <tj@kernel.org>2013-05-14 13:52:31 -0700
commitdb61367038dcd222476881cb09fd54661b3cd508 (patch)
tree2c13a848bc64d34175ab7abbd0774b816a41f20e /block
parentaa539cb38f4f1365ad52fed6a857b25f8b4dc06c (diff)
downloadlinux-linaro-stable-db61367038dcd222476881cb09fd54661b3cd508.tar.gz
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>
Diffstat (limited to 'block')
-rw-r--r--block/blk-cgroup.c39
1 files changed, 22 insertions, 17 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index b950306838ad..6bbe0a939596 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)