4 files changed, 31 insertions, 56 deletions

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 05c46bae5e55..0e6353cf147a 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -297,15 +297,18 @@ static int __cpuinit _cpu_up(unsigned int cpu, int tasks_frozen)
 	int ret, nr_calls = 0;
 	void *hcpu = (void *)(long)cpu;
 	unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
+	struct task_struct *idle;
 
 	if (cpu_online(cpu) || !cpu_present(cpu))
 		return -EINVAL;
 
 	cpu_hotplug_begin();
 
-	ret = smpboot_prepare(cpu);
-	if (ret)
+	idle = idle_thread_get(cpu);
+	if (IS_ERR(idle)) {
+		ret = PTR_ERR(idle);
 		goto out;
+	}
 
 	ret = __cpu_notify(CPU_UP_PREPARE | mod, hcpu, -1, &nr_calls);
 	if (ret) {
@@ -316,7 +319,7 @@ static int __cpuinit _cpu_up(unsigned int cpu, int tasks_frozen)
 	}
 
 	/* Arch-specific enabling code. */
-	ret = __cpu_up(cpu, idle_thread_get(cpu));
+	ret = __cpu_up(cpu, idle);
 	if (ret != 0)
 		goto out_notify;
 	BUG_ON(!cpu_online(cpu));
diff --git a/kernel/smp.c b/kernel/smp.c
index 2f8b10ecf759..a61294c07f3f 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -13,6 +13,8 @@
 #include <linux/smp.h>
 #include <linux/cpu.h>
 
+#include "smpboot.h"
+
 #ifdef CONFIG_USE_GENERIC_SMP_HELPERS
 static struct {
 	struct list_head	queue;
@@ -669,6 +671,8 @@ void __init smp_init(void)
 {
 	unsigned int cpu;
 
+	idle_threads_init();
+
 	/* FIXME: This should be done in userspace --RR */
 	for_each_present_cpu(cpu) {
 		if (num_online_cpus() >= setup_max_cpus)
diff --git a/kernel/smpboot.c b/kernel/smpboot.c
index ed1576981801..e1a797e028a3 100644
--- a/kernel/smpboot.c
+++ b/kernel/smpboot.c
@@ -6,64 +6,42 @@
 #include <linux/init.h>
 #include <linux/sched.h>
 #include <linux/percpu.h>
-#include <linux/workqueue.h>
 
 #include "smpboot.h"
 
 #ifdef CONFIG_GENERIC_SMP_IDLE_THREAD
-struct create_idle {
-	struct work_struct	work;
-	struct task_struct	*idle;
-	struct completion	done;
-	unsigned int cpu;
-};
-
-static void __cpuinit do_fork_idle(struct work_struct *work)
-{
-	struct create_idle *c = container_of(work, struct create_idle, work);
-
-	c->idle = fork_idle(c->cpu);
-	complete(&c->done);
-}
-
-static struct task_struct * __cpuinit idle_thread_create(unsigned int cpu)
-{
-	struct create_idle c_idle = {
-		.cpu	= cpu,
-		.done	= COMPLETION_INITIALIZER_ONSTACK(c_idle.done),
-	};
-
-	INIT_WORK_ONSTACK(&c_idle.work, do_fork_idle);
-	schedule_work(&c_idle.work);
-	wait_for_completion(&c_idle.done);
-	destroy_work_on_stack(&c_idle.work);
-	return c_idle.idle;
-}
-
 /*
  * For the hotplug case we keep the task structs around and reuse
  * them.
  */
 static DEFINE_PER_CPU(struct task_struct *, idle_threads);
 
-static inline struct task_struct *get_idle_for_cpu(unsigned int cpu)
+struct task_struct * __cpuinit idle_thread_get(unsigned int cpu)
 {
 	struct task_struct *tsk = per_cpu(idle_threads, cpu);
 
 	if (!tsk)
-		return idle_thread_create(cpu);
+		return ERR_PTR(-ENOMEM);
 	init_idle(tsk, cpu);
 	return tsk;
 }
 
-struct task_struct * __cpuinit idle_thread_get(unsigned int cpu)
+void __init idle_thread_set_boot_cpu(void)
 {
-	return per_cpu(idle_threads, cpu);
+	per_cpu(idle_threads, smp_processor_id()) = current;
 }
 
-void __init idle_thread_set_boot_cpu(void)
+static inline void idle_init(unsigned int cpu)
 {
-	per_cpu(idle_threads, smp_processor_id()) = current;
+	struct task_struct *tsk = per_cpu(idle_threads, cpu);
+
+	if (!tsk) {
+		tsk = fork_idle(cpu);
+		if (IS_ERR(tsk))
+			pr_err("SMP: fork_idle() failed for CPU %u\n", cpu);
+		else
+			per_cpu(idle_threads, cpu) = tsk;
+	}
 }
 
 /**
@@ -72,25 +50,13 @@ void __init idle_thread_set_boot_cpu(void)
  *
  * Creates the thread if it does not exist.
  */
-static int __cpuinit idle_thread_init(unsigned int cpu)
+void __init idle_threads_init(void)
 {
-	struct task_struct *idle = get_idle_for_cpu(cpu);
+	unsigned int cpu;
 
-	if (IS_ERR(idle)) {
-		printk(KERN_ERR "failed fork for CPU %u\n", cpu);
-		return PTR_ERR(idle);
+	for_each_possible_cpu(cpu) {
+		if (cpu != smp_processor_id())
+			idle_init(cpu);
 	}
-	per_cpu(idle_threads, cpu) = idle;
-	return 0;
 }
-#else
-static inline int idle_thread_init(unsigned int cpu) { return 0; }
 #endif
-
-/**
- * smpboot_prepare - generic smpboot preparation
- */
-int __cpuinit smpboot_prepare(unsigned int cpu)
-{
-	return idle_thread_init(cpu);
-}
diff --git a/kernel/smpboot.h b/kernel/smpboot.h
index 7943bbbab917..4cfbcb8a8362 100644
--- a/kernel/smpboot.h
+++ b/kernel/smpboot.h
@@ -8,9 +8,11 @@ int smpboot_prepare(unsigned int cpu);
 #ifdef CONFIG_GENERIC_SMP_IDLE_THREAD
 struct task_struct *idle_thread_get(unsigned int cpu);
 void idle_thread_set_boot_cpu(void);
+void idle_threads_init(void);
 #else
 static inline struct task_struct *idle_thread_get(unsigned int cpu) { return NULL; }
 static inline void idle_thread_set_boot_cpu(void) { }
+static inline void idle_threads_init(unsigned int cpu) { }
 #endif
 
 #endif