RCU needs to check if the cpu hotplug lock is held, in the middle of
other conditions to check the sanity of RCU-nocb. Provide a helper for
that.
Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxx>
Cc: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Cc: Lai Jiangshan <jiangshanlai@xxxxxxxxx>
Cc: Joel Fernandes <joel@xxxxxxxxxxxxxxxxx>
Cc: Neeraj Upadhyay <neeraju@xxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Boqun Feng <boqun.feng@xxxxxxxxx>
---
include/linux/cpu.h | 1 +
kernel/cpu.c | 7 +++++++
2 files changed, 8 insertions(+)
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index d6428aaf67e7..27eb3875e45a 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -118,6 +118,7 @@ extern void cpus_read_lock(void);
extern void cpus_read_unlock(void);
extern int cpus_read_trylock(void);
extern void lockdep_assert_cpus_held(void);
+extern int lockdep_is_cpus_held(void);
extern void cpu_hotplug_disable(void);
extern void cpu_hotplug_enable(void);
void clear_tasks_mm_cpumask(int cpu);
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 6ff2578ecf17..3cca5b27de25 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -330,6 +330,13 @@ void lockdep_assert_cpus_held(void)
percpu_rwsem_assert_held(&cpu_hotplug_lock);
}
+#ifdef CONFIG_LOCKDEP
+int lockdep_is_cpus_held(void)
+{
+ return percpu_rwsem_is_held(&cpu_hotplug_lock);
+}
+#endif
+
static void lockdep_acquire_cpus_lock(void)
{
rwsem_acquire(&cpu_hotplug_lock.dep_map, 0, 0, _THIS_IP_);
--
2.25.1
