X-Git-Url: http://pilppa.org/gitweb/?a=blobdiff_plain;f=kernel%2Fcpu.c;h=d61ba88f34e57b90edae90342ed1db59ebfbb59c;hb=d11ea48aab3b57cc931cc7120603e1c2ffb04302;hp=53d8263ae12ebc00483a3ad999177799003467e2;hpb=aef7b83c92dd0b7e994805440655d1d64147287b;p=linux-2.6-omap-h63xx.git

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 53d8263ae12..f230f9ae01c 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -13,35 +13,69 @@
 #include <linux/module.h>
 #include <linux/kthread.h>
 #include <linux/stop_machine.h>
-#include <asm/semaphore.h>
+#include <linux/mutex.h>
 
 /* This protects CPUs going up and down... */
-DECLARE_MUTEX(cpucontrol);
+static DEFINE_MUTEX(cpu_add_remove_lock);
+static DEFINE_MUTEX(cpu_bitmask_lock);
 
-static struct notifier_block *cpu_chain;
+static __cpuinitdata BLOCKING_NOTIFIER_HEAD(cpu_chain);
 
-/* Need to know about CPUs going up/down? */
-int register_cpu_notifier(struct notifier_block *nb)
+#ifdef CONFIG_HOTPLUG_CPU
+
+/* Crappy recursive lock-takers in cpufreq! Complain loudly about idiots */
+static struct task_struct *recursive;
+static int recursive_depth;
+
+void lock_cpu_hotplug(void)
 {
-	int ret;
+	struct task_struct *tsk = current;
+
+	if (tsk == recursive) {
+		static int warnings = 10;
+		if (warnings) {
+			printk(KERN_ERR "Lukewarm IQ detected in hotplug locking\n");
+			WARN_ON(1);
+			warnings--;
+		}
+		recursive_depth++;
+		return;
+	}
+	mutex_lock(&cpu_bitmask_lock);
+	recursive = tsk;
+}
+EXPORT_SYMBOL_GPL(lock_cpu_hotplug);
 
-	if ((ret = down_interruptible(&cpucontrol)) != 0)
-		return ret;
-	ret = notifier_chain_register(&cpu_chain, nb);
-	up(&cpucontrol);
-	return ret;
+void unlock_cpu_hotplug(void)
+{
+	WARN_ON(recursive != current);
+	if (recursive_depth) {
+		recursive_depth--;
+		return;
+	}
+	mutex_unlock(&cpu_bitmask_lock);
+	recursive = NULL;
 }
+EXPORT_SYMBOL_GPL(unlock_cpu_hotplug);
+
+#endif	/* CONFIG_HOTPLUG_CPU */
+
+/* Need to know about CPUs going up/down? */
+int __cpuinit register_cpu_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&cpu_chain, nb);
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+
 EXPORT_SYMBOL(register_cpu_notifier);
 
 void unregister_cpu_notifier(struct notifier_block *nb)
 {
-	down(&cpucontrol);
-	notifier_chain_unregister(&cpu_chain, nb);
-	up(&cpucontrol);
+	blocking_notifier_chain_unregister(&cpu_chain, nb);
 }
 EXPORT_SYMBOL(unregister_cpu_notifier);
 
-#ifdef CONFIG_HOTPLUG_CPU
 static inline void check_for_tasks(int cpu)
 {
 	struct task_struct *p;
@@ -80,9 +114,7 @@ int cpu_down(unsigned int cpu)
 	struct task_struct *p;
 	cpumask_t old_allowed, tmp;
 
-	if ((err = lock_cpu_hotplug_interruptible()) != 0)
-		return err;
-
+	mutex_lock(&cpu_add_remove_lock);
 	if (num_online_cpus() == 1) {
 		err = -EBUSY;
 		goto out;
@@ -93,7 +125,7 @@ int cpu_down(unsigned int cpu)
 		goto out;
 	}
 
-	err = notifier_call_chain(&cpu_chain, CPU_DOWN_PREPARE,
+	err = blocking_notifier_call_chain(&cpu_chain, CPU_DOWN_PREPARE,
 						(void *)(long)cpu);
 	if (err == NOTIFY_BAD) {
 		printk("%s: attempt to take down CPU %u failed\n",
@@ -108,10 +140,13 @@ int cpu_down(unsigned int cpu)
 	cpu_clear(cpu, tmp);
 	set_cpus_allowed(current, tmp);
 
+	mutex_lock(&cpu_bitmask_lock);
 	p = __stop_machine_run(take_cpu_down, NULL, cpu);
+	mutex_unlock(&cpu_bitmask_lock);
+
 	if (IS_ERR(p)) {
 		/* CPU didn't die: tell everyone.  Can't complain. */
-		if (notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED,
+		if (blocking_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED,
 				(void *)(long)cpu) == NOTIFY_BAD)
 			BUG();
 
@@ -134,8 +169,8 @@ int cpu_down(unsigned int cpu)
 	put_cpu();
 
 	/* CPU is completely dead: tell everyone.  Too late to complain. */
-	if (notifier_call_chain(&cpu_chain, CPU_DEAD, (void *)(long)cpu)
-	    == NOTIFY_BAD)
+	if (blocking_notifier_call_chain(&cpu_chain, CPU_DEAD,
+			(void *)(long)cpu) == NOTIFY_BAD)
 		BUG();
 
 	check_for_tasks(cpu);
@@ -145,7 +180,7 @@ out_thread:
 out_allowed:
 	set_cpus_allowed(current, old_allowed);
 out:
-	unlock_cpu_hotplug();
+	mutex_unlock(&cpu_add_remove_lock);
 	return err;
 }
 #endif /*CONFIG_HOTPLUG_CPU*/
@@ -155,14 +190,13 @@ int __devinit cpu_up(unsigned int cpu)
 	int ret;
 	void *hcpu = (void *)(long)cpu;
 
-	if ((ret = down_interruptible(&cpucontrol)) != 0)
-		return ret;
-
+	mutex_lock(&cpu_add_remove_lock);
 	if (cpu_online(cpu) || !cpu_present(cpu)) {
 		ret = -EINVAL;
 		goto out;
 	}
-	ret = notifier_call_chain(&cpu_chain, CPU_UP_PREPARE, hcpu);
+
+	ret = blocking_notifier_call_chain(&cpu_chain, CPU_UP_PREPARE, hcpu);
 	if (ret == NOTIFY_BAD) {
 		printk("%s: attempt to bring up CPU %u failed\n",
 				__FUNCTION__, cpu);
@@ -171,19 +205,21 @@ int __devinit cpu_up(unsigned int cpu)
 	}
 
 	/* Arch-specific enabling code. */
+	mutex_lock(&cpu_bitmask_lock);
 	ret = __cpu_up(cpu);
+	mutex_unlock(&cpu_bitmask_lock);
 	if (ret != 0)
 		goto out_notify;
-	if (!cpu_online(cpu))
-		BUG();
+	BUG_ON(!cpu_online(cpu));
 
 	/* Now call notifier in preparation. */
-	notifier_call_chain(&cpu_chain, CPU_ONLINE, hcpu);
+	blocking_notifier_call_chain(&cpu_chain, CPU_ONLINE, hcpu);
 
 out_notify:
 	if (ret != 0)
-		notifier_call_chain(&cpu_chain, CPU_UP_CANCELED, hcpu);
+		blocking_notifier_call_chain(&cpu_chain,
+				CPU_UP_CANCELED, hcpu);
 out:
-	up(&cpucontrol);
+	mutex_unlock(&cpu_add_remove_lock);
 	return ret;
 }