From 31494cf3532cfee0bf5c913ac9962971aab7b1d4 Mon Sep 17 00:00:00 2001
From: Gavin Shan <gwshan@linux.vnet.ibm.com>
Date: Fri, 23 Jan 2015 14:25:06 +1100
Subject: [PATCH] powerpc/powernv: Don't alloc IRQ map if necessary

On PowerNV platform, the OPAL interrupts are exported by firmware
through device-node property (/ibm,opal::opal-interrupts). Under
some extreme circumstances (e.g. simulator), we don't have this
property found from the device tree. For that case, we shouldn't
allocate the interrupt map. Otherwise, slab complains allocating
zero sized memory chunk.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/platforms/powernv/opal.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index 933c7fbd6b54..18fd4e71c9c1 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -708,11 +708,12 @@ static void __init opal_irq_init(struct device_node *dn)
 
 	/* Get interrupt property */
 	irqs = of_get_property(opal_node, "opal-interrupts", &irqlen);
-	pr_debug("Found %d interrupts reserved for OPAL\n",
-		 irqs ? (irqlen / 4) : 0);
+	opal_irq_count = irqs ? (irqlen / 4) : 0;
+	pr_debug("Found %d interrupts reserved for OPAL\n", opal_irq_count);
+	if (!opal_irq_count)
+		return;
 
 	/* Install interrupt handlers */
-	opal_irq_count = irqlen / 4;
 	opal_irqs = kzalloc(opal_irq_count * sizeof(unsigned int), GFP_KERNEL);
 	for (i = 0; irqs && i < opal_irq_count; i++, irqs++) {
 		unsigned int irq, virq;
-- 
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