[PATCH -next 2/4] cpuset: add helpers for cpuset related locks

[Chen Ridong]

From: Chen Ridong <chenridong@xxxxxxxxxx>

Add guard_cpus_read_and_cpuset and guard_cpuset helpers for cpuset, which
will be user for subsequent patched to make code concise;

Signed-off-by: Chen Ridong <chenridong@xxxxxxxxxx>
---
 include/linux/cpuset.h          |  1 +
 kernel/cgroup/cpuset-internal.h |  2 ++
 kernel/cgroup/cpuset.c          | 11 +++++++++++
 3 files changed, 14 insertions(+)

diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
index 2ddb256187b5..6153de28acf0 100644
--- a/include/linux/cpuset.h
+++ b/include/linux/cpuset.h
@@ -74,6 +74,7 @@ extern void inc_dl_tasks_cs(struct task_struct *task);
 extern void dec_dl_tasks_cs(struct task_struct *task);
 extern void cpuset_lock(void);
 extern void cpuset_unlock(void);
+extern void guard_cpuset(void);
 extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask);
 extern bool cpuset_cpus_allowed_fallback(struct task_struct *p);
 extern bool cpuset_cpu_is_isolated(int cpu);
diff --git a/kernel/cgroup/cpuset-internal.h b/kernel/cgroup/cpuset-internal.h
index 75b3aef39231..084e19fe33d5 100644
--- a/kernel/cgroup/cpuset-internal.h
+++ b/kernel/cgroup/cpuset-internal.h
@@ -277,6 +277,8 @@ ssize_t cpuset_write_resmask(struct kernfs_open_file *of,
 				    char *buf, size_t nbytes, loff_t off);
 int cpuset_common_seq_show(struct seq_file *sf, void *v);
 
+void guard_cpus_read_and_cpuset(void);
+
 /*
  * cpuset-v1.c
  */
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index cf7cd2255265..f6cdb5cdffe8 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -260,6 +260,17 @@ void cpuset_unlock(void)
 	mutex_unlock(&cpuset_mutex);
 }
 
+void guard_cpuset(void)
+{
+	guard(mutex)(&cpuset_mutex);
+}
+
+void guard_cpus_read_and_cpuset(void)
+{
+	guard(cpus_read_lock)();
+	guard(mutex)(&cpuset_mutex);
+}
+
 static DEFINE_SPINLOCK(callback_lock);
 
 void cpuset_callback_lock_irq(void)
-- 
2.34.1