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blkcg: implement all_blkcgs list

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Add all_blkcgs list goes through blkcg->all_blkcgs_node and is
protected by blkcg_pol_mutex.  This will be used to fix
blkcg_policy_data allocation bug.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Arianna Avanzini <avanzini.arianna@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Tejun Heo 2015-07-09 16:39:49 -04:00 committed by Jens Axboe
parent 144232b342
commit 7876f930d0
2 changed files with 13 additions and 5 deletions
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17
block/blk-cgroup.c
View File

@ -46,6 +46,8 @@ struct cgroup_subsys_state * const blkcg_root_css = &blkcg_root.css;
static struct blkcg_policy *blkcg_policy[BLKCG_MAX_POLS];
static LIST_HEAD(all_blkcgs); /* protected by blkcg_pol_mutex */
static bool blkcg_policy_enabled(struct request_queue *q,
const struct blkcg_policy *pol)
{
@ -817,6 +819,10 @@ static void blkcg_css_free(struct cgroup_subsys_state *css)
{
struct blkcg *blkcg = css_to_blkcg(css);
mutex_lock(&blkcg_pol_mutex);
list_del(&blkcg->all_blkcgs_node);
mutex_unlock(&blkcg_pol_mutex);
if (blkcg != &blkcg_root) {
int i;
@ -833,6 +839,8 @@ blkcg_css_alloc(struct cgroup_subsys_state *parent_css)
struct cgroup_subsys_state *ret;
int i;
mutex_lock(&blkcg_pol_mutex);
if (!parent_css) {
blkcg = &blkcg_root;
goto done;
@ -844,8 +852,6 @@ blkcg_css_alloc(struct cgroup_subsys_state *parent_css)
goto free_blkcg;
}
mutex_lock(&blkcg_pol_mutex);
for (i = 0; i < BLKCG_MAX_POLS ; i++) {
struct blkcg_policy *pol = blkcg_policy[i];
struct blkcg_policy_data *cpd;
@ -862,7 +868,6 @@ blkcg_css_alloc(struct cgroup_subsys_state *parent_css)
BUG_ON(blkcg->pd[i]);
cpd = kzalloc(pol->cpd_size, GFP_KERNEL);
if (!cpd) {
mutex_unlock(&blkcg_pol_mutex);
ret = ERR_PTR(-ENOMEM);
goto free_pd_blkcg;
}
@ -871,7 +876,6 @@ blkcg_css_alloc(struct cgroup_subsys_state *parent_css)
pol->cpd_init_fn(blkcg);
}
mutex_unlock(&blkcg_pol_mutex);
done:
spin_lock_init(&blkcg->lock);
INIT_RADIX_TREE(&blkcg->blkg_tree, GFP_ATOMIC);
@ -879,14 +883,17 @@ done:
#ifdef CONFIG_CGROUP_WRITEBACK
INIT_LIST_HEAD(&blkcg->cgwb_list);
#endif
list_add_tail(&blkcg->all_blkcgs_node, &all_blkcgs);
mutex_unlock(&blkcg_pol_mutex);
return &blkcg->css;
free_pd_blkcg:
for (i--; i >= 0; i--)
kfree(blkcg->pd[i]);
free_blkcg:
kfree(blkcg);
mutex_unlock(&blkcg_pol_mutex);
return ret;
}

1
include/linux/blk-cgroup.h
View File

@ -47,6 +47,7 @@ struct blkcg {
struct blkcg_policy_data *pd[BLKCG_MAX_POLS];
struct list_head all_blkcgs_node;
#ifdef CONFIG_CGROUP_WRITEBACK
struct list_head cgwb_list;
#endif