[PATCH 4/5] blkcg: blkcg_activate_policy() should initialize ancestors first
From: Tejun Heo <tj@kernel.org>
Date: 2019-06-13 22:31:03
Also in:
lkml
Subsystem:
block layer, control group - block io controller (blkio), the rest · Maintainers:
Jens Axboe, Tejun Heo, Josef Bacik, Linus Torvalds
When blkcg_activate_policy() is creating blkg_policy_data for existing blkgs, it did in the wrong order - descendants first. Fix it. None of the existing controllers seem affected by this. Signed-off-by: Tejun Heo <tj@kernel.org> --- block/blk-cgroup.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 04d286934c5e..440797293235 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c@@ -1390,7 +1390,8 @@ int blkcg_activate_policy(struct request_queue *q, spin_lock_irq(&q->queue_lock); - list_for_each_entry(blkg, &q->blkg_list, q_node) { + /* blkg_list is pushed at the head, reverse walk to init parents first */ + list_for_each_entry_reverse(blkg, &q->blkg_list, q_node) { struct blkg_policy_data *pd; if (blkg->pd[pol->plid])
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2.17.1