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Commit 7876f930 authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

blkcg: implement all_blkcgs list 



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: default avatarTejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Arianna Avanzini <avanzini.arianna@gmail.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 144232b3

block/blk-cgroup.c

+12 −5
Original line number Original line Diff line number Diff line
@@ -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 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,

static bool blkcg_policy_enabled(struct request_queue *q,

				 const struct blkcg_policy *pol)

				 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);

	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) {

	if (blkcg != &blkcg_root) {

		int i;

		int i;
@@ -833,6 +839,8 @@ blkcg_css_alloc(struct cgroup_subsys_state *parent_css) 
	struct cgroup_subsys_state *ret;

	struct cgroup_subsys_state *ret;

	int i;

	int i;





	mutex_lock(&blkcg_pol_mutex);



	if (!parent_css) {

	if (!parent_css) {

		blkcg = &blkcg_root;

		blkcg = &blkcg_root;

		goto done;

		goto done;
@@ -844,8 +852,6 @@ blkcg_css_alloc(struct cgroup_subsys_state *parent_css) 
		goto free_blkcg;

		goto free_blkcg;

	}

	}





	mutex_lock(&blkcg_pol_mutex);



	for (i = 0; i < BLKCG_MAX_POLS ; i++) {

	for (i = 0; i < BLKCG_MAX_POLS ; i++) {

		struct blkcg_policy *pol = blkcg_policy[i];

		struct blkcg_policy *pol = blkcg_policy[i];

		struct blkcg_policy_data *cpd;

		struct blkcg_policy_data *cpd;
@@ -862,7 +868,6 @@ blkcg_css_alloc(struct cgroup_subsys_state *parent_css) 
		BUG_ON(blkcg->pd[i]);

		BUG_ON(blkcg->pd[i]);

		cpd = kzalloc(pol->cpd_size, GFP_KERNEL);

		cpd = kzalloc(pol->cpd_size, GFP_KERNEL);

		if (!cpd) {

		if (!cpd) {

			mutex_unlock(&blkcg_pol_mutex);

			ret = ERR_PTR(-ENOMEM);

			ret = ERR_PTR(-ENOMEM);

			goto free_pd_blkcg;

			goto free_pd_blkcg;

		}

		}
@@ -871,7 +876,6 @@ blkcg_css_alloc(struct cgroup_subsys_state *parent_css) 
		pol->cpd_init_fn(blkcg);

		pol->cpd_init_fn(blkcg);

	}

	}





	mutex_unlock(&blkcg_pol_mutex);

done:

done:

	spin_lock_init(&blkcg->lock);

	spin_lock_init(&blkcg->lock);

	INIT_RADIX_TREE(&blkcg->blkg_tree, GFP_ATOMIC);

	INIT_RADIX_TREE(&blkcg->blkg_tree, GFP_ATOMIC);
@@ -879,14 +883,17 @@ blkcg_css_alloc(struct cgroup_subsys_state *parent_css) 
#ifdef CONFIG_CGROUP_WRITEBACK

#ifdef CONFIG_CGROUP_WRITEBACK

	INIT_LIST_HEAD(&blkcg->cgwb_list);

	INIT_LIST_HEAD(&blkcg->cgwb_list);

#endif

#endif

	list_add_tail(&blkcg->all_blkcgs_node, &all_blkcgs);



	mutex_unlock(&blkcg_pol_mutex);

	return &blkcg->css;

	return &blkcg->css;





free_pd_blkcg:

free_pd_blkcg:

	for (i--; i >= 0; i--)

	for (i--; i >= 0; i--)

		kfree(blkcg->pd[i]);

		kfree(blkcg->pd[i]);



free_blkcg:

free_blkcg:

	kfree(blkcg);

	kfree(blkcg);

	mutex_unlock(&blkcg_pol_mutex);

	return ret;

	return ret;

}

}

include/linux/blk-cgroup.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -47,6 +47,7 @@ struct blkcg { 




	struct blkcg_policy_data	*pd[BLKCG_MAX_POLS];

	struct blkcg_policy_data	*pd[BLKCG_MAX_POLS];





	struct list_head		all_blkcgs_node;

#ifdef CONFIG_CGROUP_WRITEBACK

#ifdef CONFIG_CGROUP_WRITEBACK

	struct list_head		cgwb_list;

	struct list_head		cgwb_list;

#endif

#endif