1 files changed, 10 insertions, 21 deletions

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 6ba0f1ecb212..1c8ddd6ee940 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -209,9 +209,12 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
                 return -ENOMEM;
 
         cpu_hotplug_begin();
+        set_cpu_active(cpu, false);
         err = __raw_notifier_call_chain(&cpu_chain, CPU_DOWN_PREPARE | mod,
                                         hcpu, -1, &nr_calls);
         if (err == NOTIFY_BAD) {
+                set_cpu_active(cpu, true);
+
                 nr_calls--;
                 __raw_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED | mod,
                                           hcpu, nr_calls, NULL);
@@ -223,11 +226,11 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
 
         /* Ensure that we are not runnable on dying cpu */
         cpumask_copy(old_allowed, &current->cpus_allowed);
-        set_cpus_allowed_ptr(current,
-                             cpumask_of(cpumask_any_but(cpu_online_mask, cpu)));
+        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);
                 /* CPU didn't die: tell everyone.  Can't complain. */
                 if (raw_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED | mod,
                                             hcpu) == NOTIFY_BAD)
@@ -278,23 +281,8 @@ int __ref cpu_down(unsigned int cpu)
                 goto out;
         }
 
-        set_cpu_active(cpu, false);
-
-        /*
-         * Make sure the all cpus did the reschedule and are not
-         * using stale version of the cpu_active_mask.
-         * This is not strictly necessary becuase stop_machine()
-         * that we run down the line already provides the required
-         * synchronization. But it's really a side effect and we do not
-         * want to depend on the innards of the stop_machine here.
-         */
-        synchronize_sched();
-
         err = _cpu_down(cpu, 0);
 
-        if (cpu_online(cpu))
-                set_cpu_active(cpu, true);
-
 out:
         cpu_maps_update_done();
         stop_machine_destroy();
@@ -383,19 +371,20 @@ int disable_nonboot_cpus(void)
                 return error;
         cpu_maps_update_begin();
         first_cpu = cpumask_first(cpu_online_mask);
-        /* We take down all of the non-boot CPUs in one shot to avoid races
+        /*
+         * We take down all of the non-boot CPUs in one shot to avoid races
          * with the userspace trying to use the CPU hotplug at the same time
          */
         cpumask_clear(frozen_cpus);
+
         printk("Disabling non-boot CPUs ...\n");
         for_each_online_cpu(cpu) {
                 if (cpu == first_cpu)
                         continue;
                 error = _cpu_down(cpu, 1);
-                if (!error) {
+                if (!error)
                         cpumask_set_cpu(cpu, frozen_cpus);
-                        printk("CPU%d is down\n", cpu);
-                } else {
+                else {
                         printk(KERN_ERR "Error taking CPU%d down: %d\n",
                                 cpu, error);
                         break;