irq: replace loop with nr_irqs with for_each_irq_desc

There are a handful of loops that go from 0 to nr_irqs and use
get_irq_desc() on them. These would allocate all the irq_desc
entries, regardless of the need for them.

Use the smarter for_each_irq_desc() iterator that will only iterate
over the present ones.

v2: make sure arch without GENERIC_HARDIRQS work too

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 3 insertions, 3 deletions

diff --git a/arch/x86/kernel/io_apic_64.c b/arch/x86/kernel/io_apic_64.c
index 51ef7eb75f2e..708be9724daf 100644
--- a/arch/x86/kernel/io_apic_64.c
+++ b/arch/x86/kernel/io_apic_64.c
@@ -1871,10 +1871,10 @@ unmask:
 
 static void ir_irq_migration(struct work_struct *work)
 {
-        int irq;
+        unsigned int irq;
+        struct irq_desc *desc;
 
-        for (irq = 0; irq < nr_irqs; irq++) {
-                struct irq_desc *desc = irq_to_desc(irq);
+        for_each_irq_desc(irq, desc) {
                 if (desc->status & IRQ_MOVE_PENDING) {
                         unsigned long flags;