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blk-cgroup: cgroup_rstat_updated() shouldn't be called on cgroup1

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Currently, cgroup rstat is supported only on cgroup2 hierarchy and
rstat functions shouldn't be called on cgroup1 cgroups.  While
converting blk-cgroup core statistics to rstat, f733164829
("blk-cgroup: reimplement basic IO stats using cgroup rstat")
accidentally ended up calling cgroup_rstat_updated() on cgroup1
cgroups causing crashes.

Longer term, we probably should add cgroup1 support to rstat but for
now let's mask the call directly.

Fixes: f733164829 ("blk-cgroup: reimplement basic IO stats using cgroup rstat")
Tested-by: Faiz Abbas <faiz_abbas@ti.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Tejun Heo 2019-11-14 14:31:28 -08:00 committed by Jens Axboe
parent de678bc63c
commit 496074f94b
1 changed files with 2 additions and 1 deletions
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3
include/linux/blk-cgroup.h
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@ -626,7 +626,8 @@ static inline bool blkcg_bio_issue_check(struct request_queue *q,
bis->cur.ios[rwd]++;
u64_stats_update_end(&bis->sync);
cgroup_rstat_updated(blkg->blkcg->css.cgroup, cpu);
if (cgroup_subsys_on_dfl(io_cgrp_subsys))
cgroup_rstat_updated(blkg->blkcg->css.cgroup, cpu);
put_cpu();
}