[tip:irq/core] genirq: Fix can_request_irq() for IRQs without an action

[tip-bot for Ben Hutchings <tipbot@zytor.com>]

Commit-ID:  2779db8d37d4b542d9ca2575f5f178dbeaca6c86
Gitweb:     http://git.kernel.org/tip/2779db8d37d4b542d9ca2575f5f178dbeaca6c86
Author:     Ben Hutchings <ben@decadent.org.uk>
AuthorDate: Fri, 28 Jun 2013 02:40:30 +0100
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Fri, 28 Jun 2013 12:56:03 +0200

genirq: Fix can_request_irq() for IRQs without an action

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@rhi.hi.is>
Tested-by: Bjarni Ingi Gislason <bjarniig@rhi.hi.is> (against 3.2)
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: 709647@bugs.debian.org
Cc: stable@vger.kernel.org # 2.6.39+
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@linutronix.de>
---
 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 e16caa8..514bcfd 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -555,9 +555,9 @@ 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;