From c15d4d6d95dc85dced59a11af1d9720c25b570d2 Mon Sep 17 00:00:00 2001
From: Mike Travis <travis@sgi.com>
Date: Sat, 10 Jan 2009 22:24:06 -0800
Subject: [PATCH] --- yaml --- r: 136381 b: refs/heads/master c:
 0fa0ebbf15addc1be8f73325d809c8547a9de304 h: refs/heads/master i:   136379:
 cc11ea876906f0e4879e483ed9e4c0dbf3d071ae v: v3

---
 [refs]                       |  2 +-
 trunk/kernel/irq/handle.c    | 11 +++++++++--
 trunk/kernel/irq/internals.h |  7 +++++++
 3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/[refs] b/[refs]
index 96816cf4c90f..34ef88096b9b 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: e2f4d06545ec1f29b0e838ee34cbf3500ea5b9a4
+refs/heads/master: 0fa0ebbf15addc1be8f73325d809c8547a9de304
diff --git a/trunk/kernel/irq/handle.c b/trunk/kernel/irq/handle.c
index fd1ef16252f4..d0b8f7e72790 100644
--- a/trunk/kernel/irq/handle.c
+++ b/trunk/kernel/irq/handle.c
@@ -17,6 +17,7 @@
 #include <linux/kernel_stat.h>
 #include <linux/rculist.h>
 #include <linux/hash.h>
+#include <linux/bootmem.h>
 
 #include "internals.h"
 
@@ -110,7 +111,7 @@ static void init_one_irq_desc(int irq, struct irq_desc *desc, int cpu)
  */
 DEFINE_SPINLOCK(sparse_irq_lock);
 
-struct irq_desc *irq_desc_ptrs[NR_IRQS] __read_mostly;
+struct irq_desc **irq_desc_ptrs __read_mostly;
 
 static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
 	[0 ... NR_IRQS_LEGACY-1] = {
@@ -137,6 +138,9 @@ int __init early_irq_init(void)
 	desc = irq_desc_legacy;
 	legacy_count = ARRAY_SIZE(irq_desc_legacy);
 
+	/* allocate irq_desc_ptrs array based on nr_irqs */
+	irq_desc_ptrs = alloc_bootmem(nr_irqs * sizeof(void *));
+
 	for (i = 0; i < legacy_count; i++) {
 		desc[i].irq = i;
 		desc[i].kstat_irqs = kstat_irqs_legacy[i];
@@ -153,7 +157,10 @@ int __init early_irq_init(void)
 
 struct irq_desc *irq_to_desc(unsigned int irq)
 {
-	return (irq < nr_irqs) ? irq_desc_ptrs[irq] : NULL;
+	if (irq_desc_ptrs && irq < nr_irqs)
+		return irq_desc_ptrs[irq];
+
+	return NULL;
 }
 
 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
diff --git a/trunk/kernel/irq/internals.h b/trunk/kernel/irq/internals.h
index e6d0a43cc125..40416a81a0f5 100644
--- a/trunk/kernel/irq/internals.h
+++ b/trunk/kernel/irq/internals.h
@@ -16,7 +16,14 @@ extern int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
 extern struct lock_class_key irq_desc_lock_class;
 extern void init_kstat_irqs(struct irq_desc *desc, int cpu, int nr);
 extern spinlock_t sparse_irq_lock;
+
+#ifdef CONFIG_SPARSE_IRQ
+/* irq_desc_ptrs allocated at boot time */
+extern struct irq_desc **irq_desc_ptrs;
+#else
+/* irq_desc_ptrs is a fixed size array */
 extern struct irq_desc *irq_desc_ptrs[NR_IRQS];
+#endif
 
 #ifdef CONFIG_PROC_FS
 extern void register_irq_proc(unsigned int irq, struct irq_desc *desc);