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>

diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index 933c7fbd6b54d0cf4accf77f9906df962380f2e6..18fd4e71c9c13c957bcade0d7b5ccb3190ebe2ca 100644 (file)
--- 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;