genirq: add reverse iterator for irq_desc
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 38bf89f..31632aa 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -21,6 +21,10 @@
# define for_each_irq_desc(irq, desc) \
for (irq = 0, desc = irq_desc; irq < nr_irqs; irq++, desc++)
+
+# define for_each_irq_desc_reverse(irq, desc) \
+ for (irq = nr_irqs -1, desc = irq_desc + (nr_irqs -1 ); \
+ irq > 0; irq--, desc--)
#endif
#ifndef CONFIG_S390