As described in the comment of blkcg_activate_policy(), *Update of each blkg is protected by both queue and blkcg locks so that holding either lock and testing blkcg_policy_enabled() is always enough for dereferencing policy data.* with queue lock held, there is no need to hold blkcg lock in blkcg_deactivate_policy(). Similar case is in blkcg_activate_policy(), which has removed holding of blkcg lock in commit 4c55f4f9ad3001ac1fefdd8d8ca7641d18558e23.
Signed-off-by: Jiang Biao <[email protected]> Signed-off-by: Wen Yang <[email protected]> CC: Tejun Heo <[email protected]> CC: Jens Axboe <[email protected]> --- block/blk-cgroup.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index c2033a2..2b7f8d0 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -1367,17 +1367,12 @@ void blkcg_deactivate_policy(struct request_queue *q, __clear_bit(pol->plid, q->blkcg_pols); list_for_each_entry(blkg, &q->blkg_list, q_node) { - /* grab blkcg lock too while removing @pd from @blkg */ - spin_lock(&blkg->blkcg->lock); - if (blkg->pd[pol->plid]) { if (pol->pd_offline_fn) pol->pd_offline_fn(blkg->pd[pol->plid]); pol->pd_free_fn(blkg->pd[pol->plid]); blkg->pd[pol->plid] = NULL; } - - spin_unlock(&blkg->blkcg->lock); } spin_unlock_irq(q->queue_lock); -- 2.7.4
