1 files changed, 104 insertions, 78 deletions

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index cbc3828faf5f..ea119effe096 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -389,9 +389,9 @@ int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
  * allocate special interrupts that are part of the architecture.
  */
 static int
-__setup_irq(unsigned int irq, struct irq_desc * desc, struct irqaction *new)
+__setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
 {
-	struct irqaction *old, **p;
+	struct irqaction *old, **old_ptr;
 	const char *old_name = NULL;
 	unsigned long flags;
 	int shared = 0;
@@ -423,8 +423,8 @@ __setup_irq(unsigned int irq, struct irq_desc * desc, struct irqaction *new)
 	 * The following block of code has to be executed atomically
 	 */
 	spin_lock_irqsave(&desc->lock, flags);
-	p = &desc->action;
-	old = *p;
+	old_ptr = &desc->action;
+	old = *old_ptr;
 	if (old) {
 		/*
 		 * Can't share interrupts unless both agree to and are
@@ -447,8 +447,8 @@ __setup_irq(unsigned int irq, struct irq_desc * desc, struct irqaction *new)
 
 		/* add new interrupt at end of irq queue */
 		do {
-			p = &old->next;
-			old = *p;
+			old_ptr = &old->next;
+			old = *old_ptr;
 		} while (old);
 		shared = 1;
 	}
@@ -499,7 +499,7 @@ __setup_irq(unsigned int irq, struct irq_desc * desc, struct irqaction *new)
 				(int)(new->flags & IRQF_TRIGGER_MASK));
 	}
 
-	*p = new;
+	*old_ptr = new;
 
 	/* Reset broken irq detection when installing new handler */
 	desc->irq_count = 0;
@@ -549,90 +549,117 @@ int setup_irq(unsigned int irq, struct irqaction *act)
 
 	return __setup_irq(irq, desc, act);
 }
+EXPORT_SYMBOL_GPL(setup_irq);
 
-/**
- *	free_irq - free an interrupt
- *	@irq: Interrupt line to free
- *	@dev_id: Device identity to free
- *
- *	Remove an interrupt handler. The handler is removed and if the
- *	interrupt line is no longer in use by any driver it is disabled.
- *	On a shared IRQ the caller must ensure the interrupt is disabled
- *	on the card it drives before calling this function. The function
- *	does not return until any executing interrupts for this IRQ
- *	have completed.
- *
- *	This function must not be called from interrupt context.
+ /*
+ * Internal function to unregister an irqaction - used to free
+ * regular and special interrupts that are part of the architecture.
  */
-void free_irq(unsigned int irq, void *dev_id)
+static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
 {
 	struct irq_desc *desc = irq_to_desc(irq);
-	struct irqaction **p;
+	struct irqaction *action, **action_ptr;
 	unsigned long flags;
 
-	WARN_ON(in_interrupt());
+	WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
 
 	if (!desc)
-		return;
+		return NULL;
 
 	spin_lock_irqsave(&desc->lock, flags);
-	p = &desc->action;
+
+	/*
+	 * There can be multiple actions per IRQ descriptor, find the right
+	 * one based on the dev_id:
+	 */
+	action_ptr = &desc->action;
 	for (;;) {
-		struct irqaction *action = *p;
+		action = *action_ptr;
 
-		if (action) {
-			struct irqaction **pp = p;
+		if (!action) {
+			WARN(1, "Trying to free already-free IRQ %d\n", irq);
+			spin_unlock_irqrestore(&desc->lock, flags);
 
-			p = &action->next;
-			if (action->dev_id != dev_id)
-				continue;
+			return NULL;
+		}
 
-			/* Found it - now remove it from the list of entries */
-			*pp = action->next;
+		if (action->dev_id == dev_id)
+			break;
+		action_ptr = &action->next;
+	}
 
-			/* Currently used only by UML, might disappear one day.*/
+	/* Found it - now remove it from the list of entries: */
+	*action_ptr = action->next;
+
+	/* Currently used only by UML, might disappear one day: */
 #ifdef CONFIG_IRQ_RELEASE_METHOD
-			if (desc->chip->release)
-				desc->chip->release(irq, dev_id);
+	if (desc->chip->release)
+		desc->chip->release(irq, dev_id);
 #endif
 
-			if (!desc->action) {
-				desc->status |= IRQ_DISABLED;
-				if (desc->chip->shutdown)
-					desc->chip->shutdown(irq);
-				else
-					desc->chip->disable(irq);
-			}
-			spin_unlock_irqrestore(&desc->lock, flags);
-			unregister_handler_proc(irq, action);
+	/* If this was the last handler, shut down the IRQ line: */
+	if (!desc->action) {
+		desc->status |= IRQ_DISABLED;
+		if (desc->chip->shutdown)
+			desc->chip->shutdown(irq);
+		else
+			desc->chip->disable(irq);
+	}
+	spin_unlock_irqrestore(&desc->lock, flags);
+
+	unregister_handler_proc(irq, action);
+
+	/* Make sure it's not being used on another CPU: */
+	synchronize_irq(irq);
 
-			/* Make sure it's not being used on another CPU */
-			synchronize_irq(irq);
-#ifdef CONFIG_DEBUG_SHIRQ
-			/*
-			 * It's a shared IRQ -- the driver ought to be
-			 * prepared for it to happen even now it's
-			 * being freed, so let's make sure....  We do
-			 * this after actually deregistering it, to
-			 * make sure that a 'real' IRQ doesn't run in
-			 * parallel with our fake
-			 */
-			if (action->flags & IRQF_SHARED) {
-				local_irq_save(flags);
-				action->handler(irq, dev_id);
-				local_irq_restore(flags);
-			}
-#endif
-			kfree(action);
-			return;
-		}
-		printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq);
 #ifdef CONFIG_DEBUG_SHIRQ
-		dump_stack();
-#endif
-		spin_unlock_irqrestore(&desc->lock, flags);
-		return;
+	/*
+	 * It's a shared IRQ -- the driver ought to be prepared for an IRQ
+	 * event to happen even now it's being freed, so let's make sure that
+	 * is so by doing an extra call to the handler ....
+	 *
+	 * ( We do this after actually deregistering it, to make sure that a
+	 *   'real' IRQ doesn't run in * parallel with our fake. )
+	 */
+	if (action->flags & IRQF_SHARED) {
+		local_irq_save(flags);
+		action->handler(irq, dev_id);
+		local_irq_restore(flags);
 	}
+#endif
+	return action;
+}
+
+/**
+ *	remove_irq - free an interrupt
+ *	@irq: Interrupt line to free
+ *	@act: irqaction for the interrupt
+ *
+ * Used to remove interrupts statically setup by the early boot process.
+ */
+void remove_irq(unsigned int irq, struct irqaction *act)
+{
+	__free_irq(irq, act->dev_id);
+}
+EXPORT_SYMBOL_GPL(remove_irq);
+
+/**
+ *	free_irq - free an interrupt allocated with request_irq
+ *	@irq: Interrupt line to free
+ *	@dev_id: Device identity to free
+ *
+ *	Remove an interrupt handler. The handler is removed and if the
+ *	interrupt line is no longer in use by any driver it is disabled.
+ *	On a shared IRQ the caller must ensure the interrupt is disabled
+ *	on the card it drives before calling this function. The function
+ *	does not return until any executing interrupts for this IRQ
+ *	have completed.
+ *
+ *	This function must not be called from interrupt context.
+ */
+void free_irq(unsigned int irq, void *dev_id)
+{
+	kfree(__free_irq(irq, dev_id));
 }
 EXPORT_SYMBOL(free_irq);
 
@@ -679,11 +706,12 @@ int request_irq(unsigned int irq, irq_handler_t handler,
 	 * the behavior is classified as "will not fix" so we need to
 	 * start nudging drivers away from using that idiom.
 	 */
-	if ((irqflags & (IRQF_SHARED|IRQF_DISABLED))
-			== (IRQF_SHARED|IRQF_DISABLED))
-		pr_warning("IRQ %d/%s: IRQF_DISABLED is not "
-				"guaranteed on shared IRQs\n",
-				irq, devname);
+	if ((irqflags & (IRQF_SHARED|IRQF_DISABLED)) ==
+					(IRQF_SHARED|IRQF_DISABLED)) {
+		pr_warning(
+		  "IRQ %d/%s: IRQF_DISABLED is not guaranteed on shared IRQs\n",
+			irq, devname);
+	}
 
 #ifdef CONFIG_LOCKDEP
 	/*
@@ -709,15 +737,13 @@ int request_irq(unsigned int irq, irq_handler_t handler,
 	if (!handler)
 		return -EINVAL;
 
-	action = kmalloc(sizeof(struct irqaction), GFP_KERNEL);
+	action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
 	if (!action)
 		return -ENOMEM;
 
 	action->handler = handler;
 	action->flags = irqflags;
-	cpus_clear(action->mask);
 	action->name = devname;
-	action->next = NULL;
 	action->dev_id = dev_id;
 
 	retval = __setup_irq(irq, desc, action);