cpu-hotplug: introduce cpu_notify(), __cpu_notify(), cpu_notify_nofail()

No functional change.  These are just wrappers of
raw_cpu_notifier_call_chain.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/cpu.c

@@ -134,6 +134,26 @@ int __ref register_cpu_notifier(struct notifier_block *nb)
 	return ret;
 }
 
+static int __cpu_notify(unsigned long val, void *v, int nr_to_call,
+			int *nr_calls)
+{
+	return __raw_notifier_call_chain(&cpu_chain, val, v, nr_to_call,
+					nr_calls);
+}
+
+static int cpu_notify(unsigned long val, void *v)
+{
+	return __cpu_notify(val, v, -1, NULL);
+}
+
+static void cpu_notify_nofail(unsigned long val, void *v)
+{
+	int err;
+
+	err = cpu_notify(val, v);
+	BUG_ON(err == NOTIFY_BAD);
+}
+
 #ifdef CONFIG_HOTPLUG_CPU
 
 EXPORT_SYMBOL(register_cpu_notifier);
@@ -181,8 +201,7 @@ static int __ref take_cpu_down(void *_param)
 	if (err < 0)
 		return err;
 
-	raw_notifier_call_chain(&cpu_chain, CPU_DYING | param->mod,
-				param->hcpu);
+	cpu_notify(CPU_DYING | param->mod, param->hcpu);
 
 	if (task_cpu(param->caller) == cpu)
 		move_task_off_dead_cpu(cpu, param->caller);
@@ -212,14 +231,12 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
 
 	cpu_hotplug_begin();
 	set_cpu_active(cpu, false);
-	err = __raw_notifier_call_chain(&cpu_chain, CPU_DOWN_PREPARE | mod,
-					hcpu, -1, &nr_calls);
+	err = __cpu_notify(CPU_DOWN_PREPARE | mod, hcpu, -1, &nr_calls);
 	if (err == NOTIFY_BAD) {
 		set_cpu_active(cpu, true);
 
 		nr_calls--;
-		__raw_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED | mod,
-					  hcpu, nr_calls, NULL);
+		__cpu_notify(CPU_DOWN_FAILED | mod, hcpu, nr_calls, NULL);
 		printk("%s: attempt to take down CPU %u failed\n",
 				__func__, cpu);
 		err = -EINVAL;
@@ -230,9 +247,7 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
 	if (err) {
 		set_cpu_active(cpu, true);
 		/* CPU didn't die: tell everyone.  Can't complain. */
-		if (raw_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED | mod,
-					    hcpu) == NOTIFY_BAD)
-			BUG();
+		cpu_notify_nofail(CPU_DOWN_FAILED | mod, hcpu);
 
 		goto out_release;
 	}
@@ -246,19 +261,14 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
 	__cpu_die(cpu);
 
 	/* CPU is completely dead: tell everyone.  Too late to complain. */
-	if (raw_notifier_call_chain(&cpu_chain, CPU_DEAD | mod,
-				    hcpu) == NOTIFY_BAD)
-		BUG();
+	cpu_notify_nofail(CPU_DEAD | mod, hcpu);
 
 	check_for_tasks(cpu);
 
 out_release:
 	cpu_hotplug_done();
-	if (!err) {
-		if (raw_notifier_call_chain(&cpu_chain, CPU_POST_DEAD | mod,
-					    hcpu) == NOTIFY_BAD)
-			BUG();
-	}
+	if (!err)
+		cpu_notify_nofail(CPU_POST_DEAD | mod, hcpu);
 	return err;
 }
 
@@ -293,8 +303,7 @@ static int __cpuinit _cpu_up(unsigned int cpu, int tasks_frozen)
 		return -EINVAL;
 
 	cpu_hotplug_begin();
-	ret = __raw_notifier_call_chain(&cpu_chain, CPU_UP_PREPARE | mod, hcpu,
-							-1, &nr_calls);
+	ret = __cpu_notify(CPU_UP_PREPARE | mod, hcpu, -1, &nr_calls);
 	if (ret == NOTIFY_BAD) {
 		nr_calls--;
 		printk("%s: attempt to bring up CPU %u failed\n",
@@ -312,12 +321,11 @@ static int __cpuinit _cpu_up(unsigned int cpu, int tasks_frozen)
 	set_cpu_active(cpu, true);
 
 	/* Now call notifier in preparation. */
-	raw_notifier_call_chain(&cpu_chain, CPU_ONLINE | mod, hcpu);
+	cpu_notify(CPU_ONLINE | mod, hcpu);
 
 out_notify:
 	if (ret != 0)
-		__raw_notifier_call_chain(&cpu_chain,
-				CPU_UP_CANCELED | mod, hcpu, nr_calls, NULL);
+		__cpu_notify(CPU_UP_CANCELED | mod, hcpu, nr_calls, NULL);
 	cpu_hotplug_done();
 
 	return ret;
@@ -481,7 +489,7 @@ void __cpuinit notify_cpu_starting(unsigned int cpu)
 	if (frozen_cpus != NULL && cpumask_test_cpu(cpu, frozen_cpus))
 		val = CPU_STARTING_FROZEN;
 #endif /* CONFIG_PM_SLEEP_SMP */
-	raw_notifier_call_chain(&cpu_chain, val, (void *)(long)cpu);
+	cpu_notify(val, (void *)(long)cpu);
 }
 
 #endif /* CONFIG_SMP */