4.14-stable review patch. If anyone has any objections, please let me know.
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From: Jiang Biao jiang.biao2@zte.com.cn
[ Upstream commit 946b81da114b8ba5c74bb01e57c0c6eca2bdc801 ]
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 jiang.biao2@zte.com.cn Signed-off-by: Wen Yang wen.yang99@zte.com.cn CC: Tejun Heo tj@kernel.org Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- block/blk-cgroup.c | 5 ----- 1 file changed, 5 deletions(-)
--- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -1374,17 +1374,12 @@ void blkcg_deactivate_policy(struct requ __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);