diff options
| author | Dennis Zhou (Facebook) <dennisszhou@gmail.com> | 2018-08-31 16:22:42 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-10-10 08:55:54 +0200 |
| commit | 561deb108ca412c2986afc6e7c0d4c2bc2072f62 (patch) | |
| tree | 435648ed2588b6794ff03d43188f0d60fb90d175 /include | |
| parent | 8dbbc215f2baccc0fe37cdf92c91a6ed0655f293 (diff) | |
Revert "blk-throttle: fix race between blkcg_bio_issue_check() and cgroup_rmdir()"
[ Upstream commit 6b06546206868f723f2061d703a3c3c378dcbf4c ]
This reverts commit 4c6994806f708559c2812b73501406e21ae5dcd0.
Destroying blkgs is tricky because of the nature of the relationship. A
blkg should go away when either a blkcg or a request_queue goes away.
However, blkg's pin the blkcg to ensure they remain valid. To break this
cycle, when a blkcg is offlined, blkgs put back their css ref. This
eventually lets css_free() get called which frees the blkcg.
The above commit (4c6994806f70) breaks this order of events by trying to
destroy blkgs in css_free(). As the blkgs still hold references to the
blkcg, css_free() is never called.
The race between blkcg_bio_issue_check() and cgroup_rmdir() will be
addressed in the following patch by delaying destruction of a blkg until
all writeback associated with the blkcg has been finished.
Fixes: 4c6994806f70 ("blk-throttle: fix race between blkcg_bio_issue_check() and cgroup_rmdir()")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Cc: Jiufei Xue <jiufei.xue@linux.alibaba.com>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
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>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/blk-cgroup.h | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h index 0fce47d5acb1..5d46b83d4820 100644 --- a/include/linux/blk-cgroup.h +++ b/include/linux/blk-cgroup.h @@ -88,7 +88,6 @@ struct blkg_policy_data { /* the blkg and policy id this per-policy data belongs to */ struct blkcg_gq *blkg; int plid; - bool offline; }; /* |