From 035d10b2fa7e5f7e9bf9465dbc39c35affd5ac32 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 5 Mar 2012 13:15:04 -0800 Subject: 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: Tejun Heo Cc: Vivek Goyal Signed-off-by: Jens Axboe --- block/blk-cgroup.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'block/blk-cgroup.c') diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 5e50ca1f5b47..f1b08d3cba55 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -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); -- cgit v1.2.3