[sysctl] Fix breakage on systems with older glibc

[safe/jmp/linux-2.6] / kernel / cpu.c

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 8ce1004..291ac58 100644 (file)
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -212,6 +212,8 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
        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 +225,11 @@ 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)
@@ -292,9 +294,6 @@ int __ref cpu_down(unsigned int cpu)
 
        err = _cpu_down(cpu, 0);
 
-       if (cpu_online(cpu))
-               set_cpu_active(cpu, true);
-
 out:
        cpu_maps_update_done();
        stop_machine_destroy();
@@ -387,20 +386,29 @@ int disable_nonboot_cpus(void)
         * with the userspace trying to use the CPU hotplug at the same time
         */
        cpumask_clear(frozen_cpus);
+
+       for_each_online_cpu(cpu) {
+               if (cpu == first_cpu)
+                       continue;
+               set_cpu_active(cpu, false);
+       }
+
+       synchronize_sched();
+
        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;
                }
        }
+
        if (!error) {
                BUG_ON(num_online_cpus() > 1);
                /* Make sure the CPUs won't be enabled by someone else */
@@ -413,6 +421,14 @@ int disable_nonboot_cpus(void)
        return error;
 }
 
+void __weak arch_enable_nonboot_cpus_begin(void)
+{
+}
+
+void __weak arch_enable_nonboot_cpus_end(void)
+{
+}
+
 void __ref enable_nonboot_cpus(void)
 {
        int cpu, error;
@@ -424,6 +440,9 @@ void __ref enable_nonboot_cpus(void)
                goto out;
 
        printk("Enabling non-boot CPUs ...\n");
+
+       arch_enable_nonboot_cpus_begin();
+
        for_each_cpu(cpu, frozen_cpus) {
                error = _cpu_up(cpu, 1);
                if (!error) {
@@ -432,6 +451,9 @@ void __ref enable_nonboot_cpus(void)
                }
                printk(KERN_WARNING "Error taking CPU%d up: %d\n", cpu, error);
        }
+
+       arch_enable_nonboot_cpus_end();
+
        cpumask_clear(frozen_cpus);
 out:
        cpu_maps_update_done();