cpu-hotplug: replace lock_cpu_hotplug() with get_online_cpus()
Replace all lock_cpu_hotplug/unlock_cpu_hotplug from the kernel and use
get_online_cpus and put_online_cpus instead as it highlights the
refcount semantics in these operations.
The new API guarantees protection against the cpu-hotplug operation, but
it doesn't guarantee serialized access to any of the local data
structures. Hence the changes needs to be reviewed.
In case of pseries_add_processor/pseries_remove_processor, use
cpu_maps_update_begin()/cpu_maps_update_done() as we're modifying the
cpu_present_map there.
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 656dc3f..b0c4152 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -48,7 +48,7 @@
#ifdef CONFIG_HOTPLUG_CPU
-void lock_cpu_hotplug(void)
+void get_online_cpus(void)
{
might_sleep();
if (cpu_hotplug.active_writer == current)
@@ -58,9 +58,9 @@
mutex_unlock(&cpu_hotplug.lock);
}
-EXPORT_SYMBOL_GPL(lock_cpu_hotplug);
+EXPORT_SYMBOL_GPL(get_online_cpus);
-void unlock_cpu_hotplug(void)
+void put_online_cpus(void)
{
if (cpu_hotplug.active_writer == current)
return;
@@ -73,7 +73,7 @@
mutex_unlock(&cpu_hotplug.lock);
}
-EXPORT_SYMBOL_GPL(unlock_cpu_hotplug);
+EXPORT_SYMBOL_GPL(put_online_cpus);
#endif /* CONFIG_HOTPLUG_CPU */
@@ -110,7 +110,7 @@
* non zero and goes to sleep again.
*
* However, this is very difficult to achieve in practice since
- * lock_cpu_hotplug() not an api which is called all that often.
+ * get_online_cpus() not an api which is called all that often.
*
*/
static void cpu_hotplug_begin(void)
