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