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| author | Johannes Weiner <hannes@cmpxchg.org> | 2014-12-10 15:44:30 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-12-10 17:41:08 -0800 |
| commit | 413918bb61b4fa027baa3e79546c47f15e4b9ea8 (patch) | |
| tree | 439c803ef6cdb6fde9a8dbef510506f519a50338 | |
| parent | c01f46c7c725f0a1330673bc3c767b89a3b2dbc0 (diff) | |
| download | op-kernel-dev-413918bb61b4fa027baa3e79546c47f15e4b9ea8.zip op-kernel-dev-413918bb61b4fa027baa3e79546c47f15e4b9ea8.tar.gz | |
mm: memcontrol: pull the NULL check from __mem_cgroup_same_or_subtree()
The NULL in mm_match_cgroup() comes from a possibly exiting mm->owner. It
makes a lot more sense to check where it's looked up, rather than check
for it in __mem_cgroup_same_or_subtree() where it's unexpected.
No other callsite passes NULL to __mem_cgroup_same_or_subtree().
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Vladimir Davydov <vdavydov@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/memcontrol.h | 5 | ||||
| -rw-r--r-- | mm/memcontrol.c | 2 |
2 files changed, 4 insertions, 3 deletions
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index ea00761..e32ab94 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -83,11 +83,12 @@ static inline bool mm_match_cgroup(const struct mm_struct *mm, const struct mem_cgroup *memcg) { struct mem_cgroup *task_memcg; - bool match; + bool match = false; rcu_read_lock(); task_memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); - match = __mem_cgroup_same_or_subtree(memcg, task_memcg); + if (task_memcg) + match = __mem_cgroup_same_or_subtree(memcg, task_memcg); rcu_read_unlock(); return match; } diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 367cc57..e5dcebd 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1337,7 +1337,7 @@ bool __mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg, { if (root_memcg == memcg) return true; - if (!root_memcg->use_hierarchy || !memcg) + if (!root_memcg->use_hierarchy) return false; return cgroup_is_descendant(memcg->css.cgroup, root_memcg->css.cgroup); } |
