genirq: use iterators for irq_desc loops

Use for_each_irq_desc[_reverse] for all the iteration loops.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index e6d47e8..9ce1ab6 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -137,14 +137,12 @@
 static void init_evtchn_cpu_bindings(void)
 {
 #ifdef CONFIG_SMP
+	struct irq_desc *desc;
 	int i;
+
 	/* By default all event channels notify CPU#0. */
-	for (i = 0; i < nr_irqs; i++) {
-		struct irq_desc *desc = irq_to_desc(i);
-		if (!desc)
-			continue;
+	for_each_irq_desc(i, desc)
 		desc->affinity = cpumask_of_cpu(0);
-	}
 #endif
 
 	memset(cpu_evtchn, 0, sizeof(cpu_evtchn));
@@ -233,7 +231,7 @@
 	int irq;
 
 	/* Only allocate from dynirq range */
-	for (irq = 0; irq < nr_irqs; irq++)
+	for_each_irq_nr(irq)
 		if (irq_bindcount[irq] == 0)
 			break;
 
@@ -794,7 +792,7 @@
 		mask_evtchn(evtchn);
 
 	/* No IRQ <-> event-channel mappings. */
-	for (irq = 0; irq < nr_irqs; irq++)
+	for_each_irq_nr(irq)
 		irq_info[irq].evtchn = 0; /* zap event-channel binding */
 
 	for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
@@ -826,7 +824,7 @@
 		mask_evtchn(i);
 
 	/* Dynamic IRQ space is currently unbound. Zero the refcnts. */
-	for (i = 0; i < nr_irqs; i++)
+	for_each_irq_nr(i)
 		irq_bindcount[i] = 0;
 
 	irq_ctx_init(smp_processor_id());