[PATCH] Remove blkg node after destroying blkg

[Tao Su]

Kernel hang when poweroff or reboot, due to infinite restart in function
blkg_destroy_all. It will goto restart label when a batch of blkgs are
destroyed, but not remove blkg node in blkg_list. So the blkg_list is
same in every 'restart' and result in kernel hang.

By adding list_del to remove blkg node after destroying, can solve this
kernel hang issue and satisfy the previous will to 'restart'.

Reported-by: Xiangfei Ma <xiangfeix.ma@xxxxxxxxx>
Tested-by: Xiangfei Ma <xiangfeix.ma@xxxxxxxxx>
Tested-by: Farrah Chen <farrah.chen@xxxxxxxxx>
Signed-off-by: Tao Su <tao1.su@xxxxxxxxxxxxxxx>
---
 block/blk-cgroup.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index bd50b55bdb61..960eb538a704 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -530,6 +530,7 @@ static void blkg_destroy_all(struct gendisk *disk)
 
 		spin_lock(&blkcg->lock);
 		blkg_destroy(blkg);
+		list_del(&blkg->q_node);
 		spin_unlock(&blkcg->lock);
 
 		/*
-- 
2.34.1