mm: kmem: remove redundant checks from get_obj_cgroup_from_current()

There are checks for current->mm and current->active_memcg in
get_obj_cgroup_from_current(), but these checks are redundant:
memcg_kmem_bypass() called just above performs same checks.

Signed-off-by: Roman Gushchin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Shakeel Butt <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Michal Hocko <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

mm/memcontrol.c

@@ -2939,9 +2939,6 @@ __always_inline struct obj_cgroup *get_obj_cgroup_from_current(void)
 	if (memcg_kmem_bypass())
 		return NULL;
 
-	if (unlikely(!current->mm && !current->active_memcg))
-		return NULL;
-
 	rcu_read_lock();
 	if (unlikely(current->active_memcg))
 		memcg = rcu_dereference(current->active_memcg);