1 files changed, 6 insertions, 20 deletions

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 25bba73b1be3..545777574779 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -164,6 +164,7 @@ static inline void check_for_tasks(int cpu)
 }
 
 struct take_cpu_down_param {
+        struct task_struct *caller;
         unsigned long mod;
         void *hcpu;
 };
@@ -172,6 +173,7 @@ 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. */
@@ -182,6 +184,8 @@ static int __ref take_cpu_down(void *_param)
         raw_notifier_call_chain(&cpu_chain, 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();
@@ -192,10 +196,10 @@ static int __ref take_cpu_down(void *_param)
 static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
 {
         int err, nr_calls = 0;
-        cpumask_var_t old_allowed;
         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,
         };
@@ -206,9 +210,6 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
         if (!cpu_online(cpu))
                 return -EINVAL;
 
-        if (!alloc_cpumask_var(&old_allowed, GFP_KERNEL))
-                return -ENOMEM;
-
         cpu_hotplug_begin();
         set_cpu_active(cpu, false);
         err = __raw_notifier_call_chain(&cpu_chain, CPU_DOWN_PREPARE | mod,
@@ -225,10 +226,6 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
                 goto out_release;
         }
 
-        /* Ensure that we are not runnable on dying cpu */
-        cpumask_copy(old_allowed, &current->cpus_allowed);
-        set_cpus_allowed_ptr(current, cpu_active_mask);
-
         err = __stop_machine(take_cpu_down, &tcd_param, cpumask_of(cpu));
         if (err) {
                 set_cpu_active(cpu, true);
@@ -237,7 +234,7 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
                                             hcpu) == NOTIFY_BAD)
                         BUG();
 
-                goto out_allowed;
+                goto out_release;
         }
         BUG_ON(cpu_online(cpu));
 
@@ -255,8 +252,6 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
 
         check_for_tasks(cpu);
 
-out_allowed:
-        set_cpus_allowed_ptr(current, old_allowed);
 out_release:
         cpu_hotplug_done();
         if (!err) {
@@ -264,7 +259,6 @@ out_release:
                                             hcpu) == NOTIFY_BAD)
                         BUG();
         }
-        free_cpumask_var(old_allowed);
         return err;
 }
 
@@ -272,9 +266,6 @@ int __ref cpu_down(unsigned int cpu)
 {
         int err;
 
-        err = stop_machine_create();
-        if (err)
-                return err;
         cpu_maps_update_begin();
 
         if (cpu_hotplug_disabled) {
@@ -286,7 +277,6 @@ int __ref cpu_down(unsigned int cpu)
 
 out:
         cpu_maps_update_done();
-        stop_machine_destroy();
         return err;
 }
 EXPORT_SYMBOL(cpu_down);
@@ -367,9 +357,6 @@ int disable_nonboot_cpus(void)
 {
         int cpu, first_cpu, error;
 
-        error = stop_machine_create();
-        if (error)
-                return error;
         cpu_maps_update_begin();
         first_cpu = cpumask_first(cpu_online_mask);
         /*
@@ -400,7 +387,6 @@ int disable_nonboot_cpus(void)
                 printk(KERN_ERR "Non-boot CPUs are not disabled\n");
         }
         cpu_maps_update_done();
-        stop_machine_destroy();
         return error;
 }