[POWERPC] Make irq_dispose_mapping(NO_IRQ) a nop

It makes for a friendlier API if irq_dispose_mapping(NO_IRQ) is a
nop, rather than triggering a WARN_ON.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 5 insertions, 1 deletions

diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 67b21a008f6e..eb9fc621e057 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -648,10 +648,14 @@ EXPORT_SYMBOL_GPL(irq_of_parse_and_map);
 
 void irq_dispose_mapping(unsigned int virq)
 {
-        struct irq_host *host = irq_map[virq].host;
+        struct irq_host *host;
         irq_hw_number_t hwirq;
         unsigned long flags;
 
+        if (virq == NO_IRQ)
+                return;
+
+        host = irq_map[virq].host;
         WARN_ON (host == NULL);
         if (host == NULL)
                 return;