[PATCH] ARM: GIC irq desciptor bug fix

[Chao at marvell.com]

From: cxie4 <cxie4 at marvell.com>

gic_set_cpu will directly use irq_desc[]. If CONFIG_SPARSE_IRQ is enabled, there is no
irq_desc[]. So we need use irq_to_desc(irq) to get the descriptor for irq.

Signed-off-by: cxie4 <cxie4 at marvell.com>
---
 arch/arm/common/gic.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/arch/arm/common/gic.c b/arch/arm/common/gic.c
index 7dfa9a8..6599acb 100644
--- a/arch/arm/common/gic.c
+++ b/arch/arm/common/gic.c
@@ -160,9 +160,15 @@ static int gic_set_cpu(unsigned int irq, const struct cpumask *mask_val)
 	unsigned int shift = (irq % 4) * 8;
 	unsigned int cpu = cpumask_first(mask_val);
 	u32 val;
+	struct irq_desc *desc;
 
 	spin_lock(&irq_controller_lock);
-	irq_desc[irq].node = cpu;
+	desc = irq_to_desc(irq);
+	if (desc == NULL) {
+		spin_unlock(&irq_controller_lock);
+		return -EINVAL;
+	}
+	desc->node = cpu;
 	val = readl(reg) & ~(0xff << shift);
 	val |= 1 << (cpu + shift);
 	writel(val, reg);
-- 
1.6.3.3