The check t->pid == t->pid is not the blessed way to check
whether a task is a group leader.
This is not about the code beautifulness only, but about
pid namespaces fixes - both the tgid and the pid fields on
the task_struct are (slowly :( ) becoming deprecated.
Besides, the thread_group_leader() macro makes only one
dereference :)
Signed-off-by: Pavel Emelyanov <[email protected]>
---
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index eb681a6..bc4cac6 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1065,7 +1065,7 @@ static void mem_cgroup_move_task(struct cgroup_subsys *ss,
* Only thread group leaders are allowed to migrate, the mm_struct is
* in effect owned by the leader
*/
- if (p->tgid != p->pid)
+ if (!thread_group_leader(p))
goto out;
css_get(&mem->css);