genirq: Fix can_request_irq() for IRQs without an action

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@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
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>

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 382a6bd..52bdd58 100644 (file)
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -539,9 +539,9 @@ 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;