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Commit 035d10b2 authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

blkcg: add blkio_policy[] array and allow one policy per policy ID 



Block cgroup policies are maintained in a linked list and,
theoretically, multiple policies sharing the same policy ID are
allowed.

This patch temporarily restricts one policy per plid and adds
blkio_policy[] array which indexes registered policy types by plid.
Both the restriction and blkio_policy[] array are transitional and
will be removed once API cleanup is complete.

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 ca32aefc

block/blk-cgroup.c

+10 −0
Original line number Diff line number Diff line
@@ -29,6 +29,8 @@ static LIST_HEAD(blkio_list); 
struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT };

EXPORT_SYMBOL_GPL(blkio_root_cgroup);



static struct blkio_policy_type *blkio_policy[BLKIO_NR_POLICIES];



static struct cgroup_subsys_state *blkiocg_create(struct cgroup_subsys *,

						  struct cgroup *);

static int blkiocg_can_attach(struct cgroup_subsys *, struct cgroup *,
@@ -1694,7 +1696,11 @@ static void blkiocg_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, 
void blkio_policy_register(struct blkio_policy_type *blkiop)

{

	spin_lock(&blkio_list_lock);



	BUG_ON(blkio_policy[blkiop->plid]);

	blkio_policy[blkiop->plid] = blkiop;

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



	spin_unlock(&blkio_list_lock);

}

EXPORT_SYMBOL_GPL(blkio_policy_register);
@@ -1702,7 +1708,11 @@ EXPORT_SYMBOL_GPL(blkio_policy_register); 
void blkio_policy_unregister(struct blkio_policy_type *blkiop)

{

	spin_lock(&blkio_list_lock);



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

	blkio_policy[blkiop->plid] = NULL;

	list_del_init(&blkiop->list);



	spin_unlock(&blkio_list_lock);

}

EXPORT_SYMBOL_GPL(blkio_policy_unregister);

block/blk-cgroup.h

+2 −0
Original line number Diff line number Diff line
@@ -19,6 +19,8 @@ 
enum blkio_policy_id {

	BLKIO_POLICY_PROP = 0,		/* Proportional Bandwidth division */

	BLKIO_POLICY_THROTL,		/* Throttling */



	BLKIO_NR_POLICIES,

};



/* Max limits for throttle policy */