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-rw-r--r--block/blk-cgroup.c96
1 files changed, 41 insertions, 55 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index c3226ce8c5f6..2a4f77f2b229 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -235,13 +235,8 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg,
blkg->online = true;
spin_unlock(&blkcg->lock);
- if (!ret) {
- if (blkcg == &blkcg_root) {
- q->root_blkg = blkg;
- q->root_rl.blkg = blkg;
- }
+ if (!ret)
return blkg;
- }
/* @blkg failed fully initialized, use the usual release path */
blkg_put(blkg);
@@ -340,15 +335,6 @@ static void blkg_destroy(struct blkcg_gq *blkg)
rcu_assign_pointer(blkcg->blkg_hint, NULL);
/*
- * If root blkg is destroyed. Just clear the pointer since root_rl
- * does not take reference on root blkg.
- */
- if (blkcg == &blkcg_root) {
- blkg->q->root_blkg = NULL;
- blkg->q->root_rl.blkg = NULL;
- }
-
- /*
* Put the reference taken at the time of creation so that when all
* queues are gone, group can be destroyed.
*/
@@ -855,9 +841,45 @@ done:
*/
int blkcg_init_queue(struct request_queue *q)
{
- might_sleep();
+ struct blkcg_gq *new_blkg, *blkg;
+ bool preloaded;
+ int ret;
+
+ new_blkg = blkg_alloc(&blkcg_root, q, GFP_KERNEL);
+ if (!new_blkg)
+ return -ENOMEM;
+
+ preloaded = !radix_tree_preload(GFP_KERNEL);
- return blk_throtl_init(q);
+ /*
+ * Make sure the root blkg exists and count the existing blkgs. As
+ * @q is bypassing at this point, blkg_lookup_create() can't be
+ * used. Open code insertion.
+ */
+ rcu_read_lock();
+ spin_lock_irq(q->queue_lock);
+ blkg = blkg_create(&blkcg_root, q, new_blkg);
+ spin_unlock_irq(q->queue_lock);
+ rcu_read_unlock();
+
+ if (preloaded)
+ radix_tree_preload_end();
+
+ if (IS_ERR(blkg)) {
+ kfree(new_blkg);
+ return PTR_ERR(blkg);
+ }
+
+ q->root_blkg = blkg;
+ q->root_rl.blkg = blkg;
+
+ ret = blk_throtl_init(q);
+ if (ret) {
+ spin_lock_irq(q->queue_lock);
+ blkg_destroy_all(q);
+ spin_unlock_irq(q->queue_lock);
+ }
+ return ret;
}
/**
@@ -958,52 +980,20 @@ int blkcg_activate_policy(struct request_queue *q,
const struct blkcg_policy *pol)
{
LIST_HEAD(pds);
- struct blkcg_gq *blkg, *new_blkg;
+ struct blkcg_gq *blkg;
struct blkg_policy_data *pd, *n;
int cnt = 0, ret;
- bool preloaded;
if (blkcg_policy_enabled(q, pol))
return 0;
- /* preallocations for root blkg */
- new_blkg = blkg_alloc(&blkcg_root, q, GFP_KERNEL);
- if (!new_blkg)
- return -ENOMEM;
-
+ /* count and allocate policy_data for all existing blkgs */
blk_queue_bypass_start(q);
-
- preloaded = !radix_tree_preload(GFP_KERNEL);
-
- /*
- * Make sure the root blkg exists and count the existing blkgs. As
- * @q is bypassing at this point, blkg_lookup_create() can't be
- * used. Open code it.
- */
spin_lock_irq(q->queue_lock);
-
- rcu_read_lock();
- blkg = __blkg_lookup(&blkcg_root, q, false);
- if (blkg)
- blkg_free(new_blkg);
- else
- blkg = blkg_create(&blkcg_root, q, new_blkg);
- rcu_read_unlock();
-
- if (preloaded)
- radix_tree_preload_end();
-
- if (IS_ERR(blkg)) {
- ret = PTR_ERR(blkg);
- goto out_unlock;
- }
-
list_for_each_entry(blkg, &q->blkg_list, q_node)
cnt++;
-
spin_unlock_irq(q->queue_lock);
- /* allocate policy_data for all existing blkgs */
while (cnt--) {
pd = kzalloc_node(pol->pd_size, GFP_KERNEL, q->node);
if (!pd) {
@@ -1072,10 +1062,6 @@ void blkcg_deactivate_policy(struct request_queue *q,
__clear_bit(pol->plid, q->blkcg_pols);
- /* if no policy is left, no need for blkgs - shoot them down */
- if (bitmap_empty(q->blkcg_pols, BLKCG_MAX_POLS))
- blkg_destroy_all(q);
-
list_for_each_entry(blkg, &q->blkg_list, q_node) {
/* grab blkcg lock too while removing @pd from @blkg */
spin_lock(&blkg->blkcg->lock);