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@@ -16,56 +16,48 @@
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#include <linux/mutex.h>
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/* This protects CPUs going up and down... */
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-static DEFINE_MUTEX(cpucontrol);
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+static DEFINE_MUTEX(cpu_add_remove_lock);
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+static DEFINE_MUTEX(cpu_bitmask_lock);
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static __cpuinitdata BLOCKING_NOTIFIER_HEAD(cpu_chain);
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#ifdef CONFIG_HOTPLUG_CPU
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-static struct task_struct *lock_cpu_hotplug_owner;
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-static int lock_cpu_hotplug_depth;
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-static int __lock_cpu_hotplug(int interruptible)
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-{
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- int ret = 0;
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-
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- if (lock_cpu_hotplug_owner != current) {
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- if (interruptible)
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- ret = mutex_lock_interruptible(&cpucontrol);
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- else
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- mutex_lock(&cpucontrol);
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- }
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-
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- /*
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- * Set only if we succeed in locking
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- */
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- if (!ret) {
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- lock_cpu_hotplug_depth++;
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- lock_cpu_hotplug_owner = current;
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- }
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-
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- return ret;
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-}
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+/* Crappy recursive lock-takers in cpufreq! Complain loudly about idiots */
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+static struct task_struct *recursive;
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+static int recursive_depth;
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void lock_cpu_hotplug(void)
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{
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- __lock_cpu_hotplug(0);
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+ struct task_struct *tsk = current;
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+
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+ if (tsk == recursive) {
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+ static int warnings = 10;
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+ if (warnings) {
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+ printk(KERN_ERR "Lukewarm IQ detected in hotplug locking\n");
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+ WARN_ON(1);
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+ warnings--;
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+ }
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+ recursive_depth++;
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+ return;
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+ }
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+ mutex_lock(&cpu_bitmask_lock);
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+ recursive = tsk;
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}
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EXPORT_SYMBOL_GPL(lock_cpu_hotplug);
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void unlock_cpu_hotplug(void)
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{
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- if (--lock_cpu_hotplug_depth == 0) {
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- lock_cpu_hotplug_owner = NULL;
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- mutex_unlock(&cpucontrol);
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+ WARN_ON(recursive != current);
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+ if (recursive_depth) {
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+ recursive_depth--;
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+ return;
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}
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+ mutex_unlock(&cpu_bitmask_lock);
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+ recursive = NULL;
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}
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EXPORT_SYMBOL_GPL(unlock_cpu_hotplug);
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-int lock_cpu_hotplug_interruptible(void)
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-{
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- return __lock_cpu_hotplug(1);
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-}
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-EXPORT_SYMBOL_GPL(lock_cpu_hotplug_interruptible);
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#endif /* CONFIG_HOTPLUG_CPU */
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/* Need to know about CPUs going up/down? */
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@@ -122,9 +114,7 @@ int cpu_down(unsigned int cpu)
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struct task_struct *p;
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cpumask_t old_allowed, tmp;
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- if ((err = lock_cpu_hotplug_interruptible()) != 0)
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- return err;
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-
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+ mutex_lock(&cpu_add_remove_lock);
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if (num_online_cpus() == 1) {
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err = -EBUSY;
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goto out;
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@@ -150,7 +140,10 @@ int cpu_down(unsigned int cpu)
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cpu_clear(cpu, tmp);
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set_cpus_allowed(current, tmp);
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+ mutex_lock(&cpu_bitmask_lock);
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p = __stop_machine_run(take_cpu_down, NULL, cpu);
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+ mutex_unlock(&cpu_bitmask_lock);
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+
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if (IS_ERR(p)) {
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/* CPU didn't die: tell everyone. Can't complain. */
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if (blocking_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED,
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@@ -187,7 +180,7 @@ out_thread:
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out_allowed:
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set_cpus_allowed(current, old_allowed);
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out:
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- unlock_cpu_hotplug();
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+ mutex_unlock(&cpu_add_remove_lock);
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return err;
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}
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#endif /*CONFIG_HOTPLUG_CPU*/
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@@ -197,9 +190,7 @@ int __devinit cpu_up(unsigned int cpu)
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int ret;
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void *hcpu = (void *)(long)cpu;
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- if ((ret = lock_cpu_hotplug_interruptible()) != 0)
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- return ret;
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-
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+ mutex_lock(&cpu_add_remove_lock);
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if (cpu_online(cpu) || !cpu_present(cpu)) {
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ret = -EINVAL;
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goto out;
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@@ -214,7 +205,9 @@ int __devinit cpu_up(unsigned int cpu)
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}
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/* Arch-specific enabling code. */
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+ mutex_lock(&cpu_bitmask_lock);
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ret = __cpu_up(cpu);
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+ mutex_unlock(&cpu_bitmask_lock);
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if (ret != 0)
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goto out_notify;
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BUG_ON(!cpu_online(cpu));
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@@ -227,6 +220,6 @@ out_notify:
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blocking_notifier_call_chain(&cpu_chain,
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CPU_UP_CANCELED, hcpu);
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out:
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- unlock_cpu_hotplug();
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+ mutex_unlock(&cpu_add_remove_lock);
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return ret;
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}
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