cpu/hotplug: Convert hotplug locking to percpu rwsem
There are no more (known) nested calls to get_online_cpus() and all
observed lock ordering problems have been addressed.
Replace the magic nested 'rwsem' hackery with a percpu-rwsem.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170524081549.447014063@linutronix.de
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index af4d660..ca73bc1 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -103,7 +103,7 @@
extern void cpus_write_unlock(void);
extern void cpus_read_lock(void);
extern void cpus_read_unlock(void);
-static inline void lockdep_assert_cpus_held(void) { }
+extern void lockdep_assert_cpus_held(void);
extern void cpu_hotplug_disable(void);
extern void cpu_hotplug_enable(void);
void clear_tasks_mm_cpumask(int cpu);