[PATCH 14/98] genirq: Fix can_request_irq() for IRQs without an action

[Luis Henriques]

3.5.7.17 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ben Hutchings <ben at decadent.org.uk>

commit 2779db8d37d4b542d9ca2575f5f178dbeaca6c86 upstream.

Commit 02725e7471b8 ('genirq: Use irq_get/put functions'),
inadvertently changed can_request_irq() to return 0 for IRQs that have
no action.  This causes pcibios_lookup_irq() to select only IRQs that
already have an action with IRQF_SHARED set, or to fail if there are
none.  Change can_request_irq() to return 1 for IRQs that have no
action (if the first two conditions are met).

Reported-by: Bjarni Ingi Gislason <bjarniig at rhi.hi.is>
Tested-by: Bjarni Ingi Gislason <bjarniig at rhi.hi.is> (against 3.2)
Signed-off-by: Ben Hutchings <ben at decadent.org.uk>
Cc: 709647 at bugs.debian.org
Link: http://bugs.debian.org/709647
Link: http://lkml.kernel.org/r/1372383630.23847.40.camel@deadeye.wl.decadent.org.uk
Signed-off-by: Thomas Gleixner <tglx at linutronix.de>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 kernel/irq/manage.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index b4c6385..a561ed3 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -554,9 +554,9 @@ int can_request_irq(unsigned int irq, unsigned long irqflags)
 		return 0;
 
 	if (irq_settings_can_request(desc)) {
-		if (desc->action)
-			if (irqflags & desc->action->flags & IRQF_SHARED)
-				canrequest =1;
+		if (!desc->action ||
+		    irqflags & desc->action->flags & IRQF_SHARED)
+			canrequest = 1;
 	}
 	irq_put_desc_unlock(desc, flags);
 	return canrequest;
-- 
1.8.1.2