genirq: Implement sane enumeration

Use the allocator bitmap to lookup active interrupts.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 16 insertions, 0 deletions

diff --git a/include/linux/irqnr.h b/include/linux/irqnr.h
index 7bf89bc8cbca..05aa8c23483f 100644
--- a/include/linux/irqnr.h
+++ b/include/linux/irqnr.h
@@ -25,6 +25,7 @@
 
 extern int nr_irqs;
 extern struct irq_desc *irq_to_desc(unsigned int irq);
+unsigned int irq_get_next_irq(unsigned int offset);
 
 # define for_each_irq_desc(irq, desc)                                   \
         for (irq = 0, desc = irq_to_desc(irq); irq < nr_irqs;           \
@@ -47,6 +48,10 @@ extern struct irq_desc *irq_to_desc(unsigned int irq);
 #define irq_node(irq)   0
 #endif
 
+# define for_each_active_irq(irq)                       \
+        for (irq = irq_get_next_irq(0); irq < nr_irqs;  \
+             irq = irq_get_next_irq(irq + 1))
+
 #endif /* CONFIG_GENERIC_HARDIRQS */
 
 #define for_each_irq_nr(irq)                   \
diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index 6312a2c83971..2e7e94ef64da 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -463,6 +463,17 @@ err:
         return ret;
 }
 
+/**
+ * irq_get_next_irq - get next allocated irq number
+ * @offset:     where to start the search
+ *
+ * Returns next irq number after offset or nr_irqs if none is found.
+ */
+unsigned int irq_get_next_irq(unsigned int offset)
+{
+        return find_next_bit(allocated_irqs, nr_irqs, offset);
+}
+
 /* Statistics access */
 void clear_kstat_irqs(struct irq_desc *desc)
 {