memcg: remove unnecessary !mm check from try_get_mem_cgroup_from_mm()

Users pass either a mm that has been established under task lock, or use a verified current->mm, which means the task can't be exiting. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> 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>

memcg: remove unnecessary !mm check from try_get_mem_cgroup_from_mm()
Users pass either a mm that has been established under task lock, or use a verified current->mm, which means the task can't be exiting. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> 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>
Johannes Weiner · Linus Torvalds · Eric Lee · Eric Lee · Eric Lee · Eric Lee
1 parent 284f39afea
Showing 1 changed file with 0 additions and 7 deletions Side-by-side Diff
mm/memcontrol.c
@@ -1075,13 +1075,6 @@
 {
 	struct mem_cgroup *memcg = NULL;
  
-	if (!mm)
-		return NULL;
-	/*
-	 * Because we have no locks, mm->owner's may be being moved to other
-	 * cgroup. We use css_tryget() here even if this looks
-	 * pessimistic (rather than adding locks here).
-	 */
 	rcu_read_lock();
 	do {
 		memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
...	...	@@ -1075,13 +1075,6 @@
1075	1075	{
1076	1076	struct mem_cgroup *memcg = NULL;
1077	1077
1078		- if (!mm)
1079		- return NULL;
1080		- /*
1081		- * Because we have no locks, mm->owner's may be being moved to other
1082		- * cgroup. We use css_tryget() here even if this looks
1083		- * pessimistic (rather than adding locks here).
1084		- */
1085	1078	rcu_read_lock();
1086	1079	do {
1087	1080	memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));