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-rw-r--r--include/linux/cgroup.h20
1 files changed, 14 insertions, 6 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 0c621604baa..e3d00fdb858 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -525,13 +525,21 @@ static inline struct cgroup_subsys_state *cgroup_subsys_state(
return cgrp->subsys[subsys_id];
}
-static inline struct cgroup_subsys_state *task_subsys_state(
- struct task_struct *task, int subsys_id)
+/*
+ * function to get the cgroup_subsys_state which allows for extra
+ * rcu_dereference_check() conditions, such as locks used during the
+ * cgroup_subsys::attach() methods.
+ */
+#define task_subsys_state_check(task, subsys_id, __c) \
+ rcu_dereference_check(task->cgroups->subsys[subsys_id], \
+ rcu_read_lock_held() || \
+ lockdep_is_held(&task->alloc_lock) || \
+ cgroup_lock_is_held() || (__c))
+
+static inline struct cgroup_subsys_state *
+task_subsys_state(struct task_struct *task, int subsys_id)
{
- return rcu_dereference_check(task->cgroups->subsys[subsys_id],
- rcu_read_lock_held() ||
- lockdep_is_held(&task->alloc_lock) ||
- cgroup_lock_is_held());
+ return task_subsys_state_check(task, subsys_id, false);
}
static inline struct cgroup* task_cgroup(struct task_struct *task,