[PATCH] srcu-3: RCU variant permitting read-side blocking

[sfrench/cifs-2.6.git] / kernel / softlockup.c

diff --git a/kernel/softlockup.c b/kernel/softlockup.c
index 2c1be1163edc4647384b829a6bb9e2db5bb41b5a..50afeb813305d76435e8c6852a80b5b9dc5c8cd9 100644 (file)
--- a/kernel/softlockup.c
+++ b/kernel/softlockup.c
@@ -104,7 +104,7 @@ static int watchdog(void * __bind_cpu)
 /*
  * Create/destroy watchdog threads as CPUs come and go:
  */
-static int
+static int __cpuinit
 cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
 {
        int hotcpu = (unsigned long)hcpu;
@@ -127,6 +127,8 @@ cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
                break;
 #ifdef CONFIG_HOTPLUG_CPU
        case CPU_UP_CANCELED:
+               if (!per_cpu(watchdog_task, hotcpu))
+                       break;
                /* Unbind so it can run.  Fall thru. */
                kthread_bind(per_cpu(watchdog_task, hotcpu),
                             any_online_cpu(cpu_online_map));
@@ -140,15 +142,16 @@ cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
        return NOTIFY_OK;
 }
 
-static struct notifier_block cpu_nfb = {
+static struct notifier_block __cpuinitdata cpu_nfb = {
        .notifier_call = cpu_callback
 };
 
 __init void spawn_softlockup_task(void)
 {
        void *cpu = (void *)(long)smp_processor_id();
+       int err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
 
-       cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
+       BUG_ON(err == NOTIFY_BAD);
        cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);
        register_cpu_notifier(&cpu_nfb);