cpu-hotplug: export cpu_hotplug_enable/cpu_hotplug_disable

[cascardo/linux.git] / kernel / cpu.c

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 6a37454..718ea76 100644 (file)
--- 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? */
@@ -527,18 +528,9 @@ static int _cpu_up(unsigned int cpu, int tasks_frozen)
                goto out_notify;
        }
 
-       /*
-        * Some architectures have to walk the irq descriptors to
-        * setup the vector space for the cpu which comes online.
-        * Prevent irq alloc/free across the bringup.
-        */
-       irq_lock_sparse();
-
        /* Arch-specific enabling code. */
        ret = __cpu_up(cpu, idle);
 
-       irq_unlock_sparse();
-
        if (ret != 0)
                goto out_notify;
        BUG_ON(!cpu_online(cpu));
@@ -617,13 +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;
 }
@@ -642,7 +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;