1 files changed, 19 insertions, 10 deletions

diff --git a/kernel/cpu.c b/kernel/cpu.c
index f6e726f18491..156cc5556140 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -189,7 +189,6 @@ static inline void check_for_tasks(int cpu)
 }
 
 struct take_cpu_down_param {
-        struct task_struct *caller;
         unsigned long mod;
         void *hcpu;
 };
@@ -198,7 +197,6 @@ struct take_cpu_down_param {
 static int __ref take_cpu_down(void *_param)
 {
         struct take_cpu_down_param *param = _param;
-        unsigned int cpu = (unsigned long)param->hcpu;
         int err;
 
         /* Ensure this CPU doesn't handle any more interrupts. */
@@ -208,11 +206,6 @@ static int __ref take_cpu_down(void *_param)
 
         cpu_notify(CPU_DYING | param->mod, param->hcpu);
 
-        if (task_cpu(param->caller) == cpu)
-                move_task_off_dead_cpu(cpu, param->caller);
-        /* Force idle task to run as soon as we yield: it should
-           immediately notice cpu is offline and die quickly. */
-        sched_idle_next();
         return 0;
 }
 
@@ -223,7 +216,6 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
         void *hcpu = (void *)(long)cpu;
         unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
         struct take_cpu_down_param tcd_param = {
-                .caller = current,
                 .mod = mod,
                 .hcpu = hcpu,
         };
@@ -253,9 +245,15 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
         }
         BUG_ON(cpu_online(cpu));
 
-        /* Wait for it to sleep (leaving idle task). */
+        /*
+         * The migration_call() CPU_DYING callback will have removed all
+         * runnable tasks from the cpu, there's only the idle task left now
+         * that the migration thread is done doing the stop_machine thing.
+         *
+         * Wait for the stop thread to go away.
+         */
         while (!idle_cpu(cpu))
-                yield();
+                cpu_relax();
 
         /* This actually kills the CPU. */
         __cpu_die(cpu);
@@ -386,6 +384,14 @@ out:
 #ifdef CONFIG_PM_SLEEP_SMP
 static cpumask_var_t frozen_cpus;
 
+void __weak arch_disable_nonboot_cpus_begin(void)
+{
+}
+
+void __weak arch_disable_nonboot_cpus_end(void)
+{
+}
+
 int disable_nonboot_cpus(void)
 {
         int cpu, first_cpu, error = 0;
@@ -397,6 +403,7 @@ int disable_nonboot_cpus(void)
          * with the userspace trying to use the CPU hotplug at the same time
          */
         cpumask_clear(frozen_cpus);
+        arch_disable_nonboot_cpus_begin();
 
         printk("Disabling non-boot CPUs ...\n");
         for_each_online_cpu(cpu) {
@@ -412,6 +419,8 @@ int disable_nonboot_cpus(void)
                 }
         }
 
+        arch_disable_nonboot_cpus_end();
+
         if (!error) {
                 BUG_ON(num_online_cpus() > 1);
                 /* Make sure the CPUs won't be enabled by someone else */