[PATCH] ppc64: allocate irqstacks only for possible cpus

With earlier setup of cpu_possible_map the number of irqstacks shrinks from
NR_CPUS to the number of possible cpus.
Signed-off-by: Nathan Lynch <nathanl@austin.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/ppc64/kernel/irq.c

@@ -931,7 +931,7 @@ void irq_ctx_init(void)
 	struct thread_info *tp;
 	int i;
 
-	for (i = 0; i < NR_CPUS; i++) {
+	for_each_cpu(i) {
 		memset((void *)softirq_ctx[i], 0, THREAD_SIZE);
 		tp = softirq_ctx[i];
 		tp->cpu = i;

arch/ppc64/kernel/setup.c

@@ -701,7 +701,7 @@ static void __init irqstack_early_init(void)
 	int i;
 
 	/* interrupt stacks must be under 256MB, we cannot afford to take SLB misses on them */
-	for (i = 0; i < NR_CPUS; i++) {
+	for_each_cpu(i) {
 		softirq_ctx[i] = (struct thread_info *)__va(lmb_alloc_base(THREAD_SIZE,
 					THREAD_SIZE, 0x10000000));
 		hardirq_ctx[i] = (struct thread_info *)__va(lmb_alloc_base(THREAD_SIZE,