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| author | Dennis Zhou (Facebook) <dennisszhou@gmail.com> | 2018-08-31 16:22:42 -0400 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2018-08-31 14:48:54 -0600 |
| commit | 6b06546206868f723f2061d703a3c3c378dcbf4c (patch) | |
| tree | 4ee94bc8c5ba5ac96a1260ab9efc6c67b4a344a9 /include | |
| parent | 52bd456a66c1abb7dd43628080025703248b1ea2 (diff) | |
| download | linux-6b06546206868f723f2061d703a3c3c378dcbf4c.tar.bz2 | |
Revert "blk-throttle: fix race between blkcg_bio_issue_check() and cgroup_rmdir()"
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>
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 34aec30e06c7..1615cdd4c797 100644 --- a/include/linux/blk-cgroup.h +++ b/include/linux/blk-cgroup.h @@ -89,7 +89,6 @@ struct blkg_policy_data { /* the blkg and policy id this per-policy data belongs to */ struct blkcg_gq *blkg; int plid; - bool offline; }; /* |