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authorHong Zhiguo <zhiguohong@tencent.com>2013-11-20 10:35:05 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-12-11 22:36:27 -0800
commit950cda7f8e2bc6f182a2640817970166c55240db (patch)
treee770f6d656a19cb92fdb0e6ad0f9b669d03d3a97 /block
parentc52348079702c2fa0fcc74e2ac5ba81c70a47fbc (diff)
downloadlinux-linaro-stable-950cda7f8e2bc6f182a2640817970166c55240db.tar.gz
Update of blkg_stat and blkg_rwstat may happen in bh context. While u64_stats_fetch_retry is only preempt_disable on 32bit UP system. This is not enough to avoid preemption by bh and may read strange 64 bit value.
commit 2c575026fae6e63771bd2a4c1d407214a8096a89 upstream. Signed-off-by: Hong Zhiguo <zhiguohong@tencent.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'block')
-rw-r--r--block/blk-cgroup.h8
1 files changed, 4 insertions, 4 deletions
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index 4e595ee8c915..749afadfbb33 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -399,9 +399,9 @@ static inline uint64_t blkg_stat_read(struct blkg_stat *stat)
uint64_t v;
do {
- start = u64_stats_fetch_begin(&stat->syncp);
+ start = u64_stats_fetch_begin_bh(&stat->syncp);
v = stat->cnt;
- } while (u64_stats_fetch_retry(&stat->syncp, start));
+ } while (u64_stats_fetch_retry_bh(&stat->syncp, start));
return v;
}
@@ -467,9 +467,9 @@ static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
struct blkg_rwstat tmp;
do {
- start = u64_stats_fetch_begin(&rwstat->syncp);
+ start = u64_stats_fetch_begin_bh(&rwstat->syncp);
tmp = *rwstat;
- } while (u64_stats_fetch_retry(&rwstat->syncp, start));
+ } while (u64_stats_fetch_retry_bh(&rwstat->syncp, start));
return tmp;
}