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-rw-r--r--include/linux/cgroup.h13
-rw-r--r--kernel/cgroup.c20
2 files changed, 15 insertions, 18 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 63deb70..515927e 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -30,7 +30,6 @@ struct css_id;
extern int cgroup_init_early(void);
extern int cgroup_init(void);
-extern int cgroup_lock_is_held(void);
extern void cgroup_fork(struct task_struct *p);
extern void cgroup_post_fork(struct task_struct *p);
extern void cgroup_exit(struct task_struct *p, int run_callbacks);
@@ -552,10 +551,16 @@ static inline struct cgroup_subsys_state *cgroup_subsys_state(
* rcu_dereference_check() conditions, such as locks used during the
* cgroup_subsys::attach() methods.
*/
+#ifdef CONFIG_PROVE_RCU
+extern struct mutex cgroup_mutex;
#define task_subsys_state_check(task, subsys_id, __c) \
- rcu_dereference_check(task->cgroups->subsys[subsys_id], \
- lockdep_is_held(&task->alloc_lock) || \
- cgroup_lock_is_held() || (__c))
+ rcu_dereference_check((task)->cgroups->subsys[(subsys_id)], \
+ lockdep_is_held(&(task)->alloc_lock) || \
+ lockdep_is_held(&cgroup_mutex) || (__c))
+#else
+#define task_subsys_state_check(task, subsys_id, __c) \
+ rcu_dereference((task)->cgroups->subsys[(subsys_id)])
+#endif
static inline struct cgroup_subsys_state *
task_subsys_state(struct task_struct *task, int subsys_id)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 1a65958..ba3e24a 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -83,7 +83,13 @@
* B happens only through cgroup_show_options() and using cgroup_root_mutex
* breaks it.
*/
+#ifdef CONFIG_PROVE_RCU
+DEFINE_MUTEX(cgroup_mutex);
+EXPORT_SYMBOL_GPL(cgroup_mutex); /* only for task_subsys_state_check() */
+#else
static DEFINE_MUTEX(cgroup_mutex);
+#endif
+
static DEFINE_MUTEX(cgroup_root_mutex);
/*
@@ -251,20 +257,6 @@ static int cgroup_destroy_locked(struct cgroup *cgrp);
static int cgroup_addrm_files(struct cgroup *cgrp, struct cgroup_subsys *subsys,
struct cftype cfts[], bool is_add);
-#ifdef CONFIG_PROVE_LOCKING
-int cgroup_lock_is_held(void)
-{
- return lockdep_is_held(&cgroup_mutex);
-}
-#else /* #ifdef CONFIG_PROVE_LOCKING */
-int cgroup_lock_is_held(void)
-{
- return mutex_is_locked(&cgroup_mutex);
-}
-#endif /* #else #ifdef CONFIG_PROVE_LOCKING */
-
-EXPORT_SYMBOL_GPL(cgroup_lock_is_held);
-
static int css_unbias_refcnt(int refcnt)
{
return refcnt >= 0 ? refcnt : refcnt - CSS_DEACT_BIAS;