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Commit bc0d6501 authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

blkcg: kill blkio_list and replace blkio_list_lock with a mutex 



With blkio_policy[], blkio_list is redundant and hinders with
per-queue policy activation.  Remove it.  Also, replace
blkio_list_lock with a mutex blkcg_pol_mutex and let it protect the
whole [un]registration.

This is to prepare for per-queue policy activation and doesn't cause
any functional difference.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent f48ec1d7

block/blk-cgroup.c

+17 −15
Original line number Original line Diff line number Diff line
@@ -24,9 +24,7 @@ 




#define MAX_KEY_LEN 100

#define MAX_KEY_LEN 100





static DEFINE_SPINLOCK(blkio_list_lock);

static DEFINE_MUTEX(blkcg_pol_mutex);

static LIST_HEAD(blkio_list);



static DEFINE_MUTEX(all_q_mutex);

static DEFINE_MUTEX(all_q_mutex);

static LIST_HEAD(all_q_list);

static LIST_HEAD(all_q_list);
@@ -311,8 +309,9 @@ blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val) 
	struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup);

	struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup);

	struct blkio_group *blkg;

	struct blkio_group *blkg;

	struct hlist_node *n;

	struct hlist_node *n;

	int i;





	spin_lock(&blkio_list_lock);

	mutex_lock(&blkcg_pol_mutex);

	spin_lock_irq(&blkcg->lock);

	spin_lock_irq(&blkcg->lock);





	/*

	/*
@@ -321,15 +320,16 @@ blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val) 
	 * anyway.  If you get hit by a race, retry.

	 * anyway.  If you get hit by a race, retry.

	 */

	 */

	hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {

	hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {

		struct blkio_policy_type *pol;

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

			struct blkio_policy_type *pol = blkio_policy[i];





		list_for_each_entry(pol, &blkio_list, list)

			if (pol && pol->ops.blkio_reset_group_stats_fn)

			if (pol->ops.blkio_reset_group_stats_fn)

				pol->ops.blkio_reset_group_stats_fn(blkg);

				pol->ops.blkio_reset_group_stats_fn(blkg);

		}

		}

	}





	spin_unlock_irq(&blkcg->lock);

	spin_unlock_irq(&blkcg->lock);

	spin_unlock(&blkio_list_lock);

	mutex_unlock(&blkcg_pol_mutex);

	return 0;

	return 0;

}

}
@@ -732,20 +732,21 @@ void blkio_policy_register(struct blkio_policy_type *blkiop) 
{

{

	struct request_queue *q;

	struct request_queue *q;





	mutex_lock(&blkcg_pol_mutex);



	blkcg_bypass_start();

	blkcg_bypass_start();

	spin_lock(&blkio_list_lock);





	BUG_ON(blkio_policy[blkiop->plid]);

	BUG_ON(blkio_policy[blkiop->plid]);

	blkio_policy[blkiop->plid] = blkiop;

	blkio_policy[blkiop->plid] = blkiop;

	list_add_tail(&blkiop->list, &blkio_list);



	spin_unlock(&blkio_list_lock);

	list_for_each_entry(q, &all_q_list, all_q_node)

	list_for_each_entry(q, &all_q_list, all_q_node)

		update_root_blkg_pd(q, blkiop->plid);

		update_root_blkg_pd(q, blkiop->plid);



	blkcg_bypass_end();

	blkcg_bypass_end();





	if (blkiop->cftypes)

	if (blkiop->cftypes)

		WARN_ON(cgroup_add_cftypes(&blkio_subsys, blkiop->cftypes));

		WARN_ON(cgroup_add_cftypes(&blkio_subsys, blkiop->cftypes));



	mutex_unlock(&blkcg_pol_mutex);

}

}

EXPORT_SYMBOL_GPL(blkio_policy_register);

EXPORT_SYMBOL_GPL(blkio_policy_register);
@@ -753,19 +754,20 @@ void blkio_policy_unregister(struct blkio_policy_type *blkiop) 
{

{

	struct request_queue *q;

	struct request_queue *q;





	mutex_lock(&blkcg_pol_mutex);



	if (blkiop->cftypes)

	if (blkiop->cftypes)

		cgroup_rm_cftypes(&blkio_subsys, blkiop->cftypes);

		cgroup_rm_cftypes(&blkio_subsys, blkiop->cftypes);





	blkcg_bypass_start();

	blkcg_bypass_start();

	spin_lock(&blkio_list_lock);





	BUG_ON(blkio_policy[blkiop->plid] != blkiop);

	BUG_ON(blkio_policy[blkiop->plid] != blkiop);

	blkio_policy[blkiop->plid] = NULL;

	blkio_policy[blkiop->plid] = NULL;

	list_del_init(&blkiop->list);





	spin_unlock(&blkio_list_lock);

	list_for_each_entry(q, &all_q_list, all_q_node)

	list_for_each_entry(q, &all_q_list, all_q_node)

		update_root_blkg_pd(q, blkiop->plid);

		update_root_blkg_pd(q, blkiop->plid);

	blkcg_bypass_end();

	blkcg_bypass_end();



	mutex_unlock(&blkcg_pol_mutex);

}

}

EXPORT_SYMBOL_GPL(blkio_policy_unregister);
 
EXPORT_SYMBOL_GPL(blkio_policy_unregister);

block/blk-cgroup.h

+0 −1
Original line number Original line Diff line number Diff line
@@ -102,7 +102,6 @@ struct blkio_policy_ops { 
};

};





struct blkio_policy_type {

struct blkio_policy_type {

	struct list_head list;

	struct blkio_policy_ops ops;

	struct blkio_policy_ops ops;

	enum blkio_policy_id plid;

	enum blkio_policy_id plid;

	size_t pdata_size;		/* policy specific private data size */

	size_t pdata_size;		/* policy specific private data size */