[PATCH 3/3] powerpc: kdump: Use chip->shutdown to disable IRQs

[Anton Blanchard <anton@samba.org>]

I saw this in a kdump kernel:

IOMMU table initialized, virtual merging enabled
Interrupt 155954 (real) is invalid, disabling it.
Interrupt 155953 (real) is invalid, disabling it.

ie we took some spurious interrupts. default_machine_crash_shutdown tries
to disable all interrupt sources but uses chip->disable which maps to
the default action of:

static void default_disable(unsigned int irq)
{
}

If we use chip->shutdown, then we actually mask the IRQ:

static void default_shutdown(unsigned int irq)
{
        struct irq_desc *desc = irq_to_desc(irq);

        desc->chip->mask(irq);
        desc->status |= IRQ_MASKED;
}

Not sure why we don't implement a ->disable action for xics.c, or why
default_disable doesn't mask the interrupt.

Signed-off-by: Anton Blanchard <anton@samba.org>
---

Index: linux-2.6/arch/powerpc/kernel/crash.c
===================================================================
--- linux-2.6.orig/arch/powerpc/kernel/crash.c	2010-05-10 23:43:10.445953883 +1000
+++ linux-2.6/arch/powerpc/kernel/crash.c	2010-05-10 23:43:21.223454012 +1000
@@ -315,7 +315,7 @@ void default_machine_crash_shutdown(stru
 			desc->chip->eoi(i);
 
 		if (!(desc->status & IRQ_DISABLED))
-			desc->chip->disable(i);
+			desc->chip->shutdown(i);
 	}
 
 	/*