From 931ef163309ee955611f287dc65248b39a65fc9d Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Fri, 26 Feb 2016 18:43:36 +0000
Subject: cpu/hotplug: Unpark smpboot threads from the state machine

Handle the smpboot threads in the state machine.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: Rik van Riel <riel@redhat.com>
Cc: Rafael Wysocki <rafael.j.wysocki@intel.com>
Cc: "Srivatsa S. Bhat" <srivatsa@mit.edu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Turner <pjt@google.com>
Link: http://lkml.kernel.org/r/20160226182341.295777684@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/cpu.c | 39 +++++----------------------------------
 1 file changed, 5 insertions(+), 34 deletions(-)

(limited to 'kernel/cpu.c')

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 65e34d3..3ec86bc 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -481,8 +481,6 @@ static int takedown_cpu(unsigned int cpu)
 	else
 		synchronize_rcu();
 
-	smpboot_park_threads(cpu);
-
 	/*
 	 * Prevent irq alloc/free while the dying cpu reorganizes the
 	 * interrupt affinities.
@@ -612,38 +610,6 @@ int cpu_down(unsigned int cpu)
 EXPORT_SYMBOL(cpu_down);
 #endif /*CONFIG_HOTPLUG_CPU*/
 
-/*
- * Unpark per-CPU smpboot kthreads at CPU-online time.
- */
-static int smpboot_thread_call(struct notifier_block *nfb,
-			       unsigned long action, void *hcpu)
-{
-	int cpu = (long)hcpu;
-
-	switch (action & ~CPU_TASKS_FROZEN) {
-
-	case CPU_DOWN_FAILED:
-	case CPU_ONLINE:
-		smpboot_unpark_threads(cpu);
-		break;
-
-	default:
-		break;
-	}
-
-	return NOTIFY_OK;
-}
-
-static struct notifier_block smpboot_thread_notifier = {
-	.notifier_call = smpboot_thread_call,
-	.priority = CPU_PRI_SMPBOOT,
-};
-
-void smpboot_thread_init(void)
-{
-	register_cpu_notifier(&smpboot_thread_notifier);
-}
-
 /**
  * notify_cpu_starting(cpu) - call the CPU_STARTING notifiers
  * @cpu: cpu that just started
@@ -959,6 +925,11 @@ static struct cpuhp_step cpuhp_bp_states[] = {
 		.startup		= cpuhp_set_cpu_active,
 		.teardown		= NULL,
 	},
+	[CPUHP_SMPBOOT_THREADS] = {
+		.name			= "smpboot:threads",
+		.startup		= smpboot_unpark_threads,
+		.teardown		= smpboot_park_threads,
+	},
 	[CPUHP_NOTIFY_ONLINE] = {
 		.name			= "notify:online",
 		.startup		= notify_online,
-- 
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