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Diffstat (limited to 'kernel')
-rw-r--r--kernel/cpu.c24
1 files changed, 15 insertions, 9 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 5644ec5582b9..718ea76b78ba 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -191,17 +191,18 @@ void cpu_hotplug_done(void)
void cpu_hotplug_disable(void)
{
cpu_maps_update_begin();
- cpu_hotplug_disabled = 1;
+ cpu_hotplug_disabled++;
cpu_maps_update_done();
}
+EXPORT_SYMBOL_GPL(cpu_hotplug_disable);
void cpu_hotplug_enable(void)
{
cpu_maps_update_begin();
- cpu_hotplug_disabled = 0;
+ WARN_ON(--cpu_hotplug_disabled < 0);
cpu_maps_update_done();
}
-
+EXPORT_SYMBOL_GPL(cpu_hotplug_enable);
#endif /* CONFIG_HOTPLUG_CPU */
/* Need to know about CPUs going up/down? */
@@ -608,13 +609,18 @@ int disable_nonboot_cpus(void)
}
}
- if (!error) {
+ if (!error)
BUG_ON(num_online_cpus() > 1);
- /* Make sure the CPUs won't be enabled by someone else */
- cpu_hotplug_disabled = 1;
- } else {
+ else
pr_err("Non-boot CPUs are not disabled\n");
- }
+
+ /*
+ * Make sure the CPUs won't be enabled by someone else. We need to do
+ * this even in case of failure as all disable_nonboot_cpus() users are
+ * supposed to do enable_nonboot_cpus() on the failure path.
+ */
+ cpu_hotplug_disabled++;
+
cpu_maps_update_done();
return error;
}
@@ -633,7 +639,7 @@ void __ref enable_nonboot_cpus(void)
/* Allow everyone to use the CPU hotplug again */
cpu_maps_update_begin();
- cpu_hotplug_disabled = 0;
+ WARN_ON(--cpu_hotplug_disabled < 0);
if (cpumask_empty(frozen_cpus))
goto out;