On Fri, Oct 24, 2014 at 09:49:48AM -0400, Johannes Weiner wrote: > 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 <[email protected]>
Reviewed-by: Vladimir Davydov <[email protected]> > --- > include/linux/memcontrol.h | 5 +++-- > mm/memcontrol.c | 2 +- > 2 files changed, 4 insertions(+), 3 deletions(-) > > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h > index ea007615e8f9..e32ab948f589 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 bdf8520979cf..15b1c5110a8f 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -1316,7 +1316,7 @@ 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); > } > -- > 2.1.2 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
