genirq: Return the IRQ name from free_irq()

This allows callers to get back at them instead of having to store it in
another variable.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

include/linux/interrupt.h

@@ -155,7 +155,7 @@ extern int __must_check
 request_percpu_irq(unsigned int irq, irq_handler_t handler,
 		   const char *devname, void __percpu *percpu_dev_id);
 
-extern void free_irq(unsigned int, void *);
+extern const void *free_irq(unsigned int, void *);
 extern void free_percpu_irq(unsigned int, void __percpu *);
 
 struct device;

kernel/irq/manage.c

@@ -1574,20 +1574,27 @@ EXPORT_SYMBOL_GPL(remove_irq);
  *	have completed.
  *
  *	This function must not be called from interrupt context.
+ *
+ *	Returns the devname argument passed to request_irq.
  */
-void free_irq(unsigned int irq, void *dev_id)
+const void *free_irq(unsigned int irq, void *dev_id)
 {
 	struct irq_desc *desc = irq_to_desc(irq);
+	struct irqaction *action;
+	const char *devname;
 
 	if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
-		return;
+		return NULL;
 
 #ifdef CONFIG_SMP
 	if (WARN_ON(desc->affinity_notify))
 		desc->affinity_notify = NULL;
 #endif
 
-	kfree(__free_irq(irq, dev_id));
+	action = __free_irq(irq, dev_id);
+	devname = action->name;
+	kfree(action);
+	return devname;
 }
 EXPORT_SYMBOL(free_irq);