[PATCH] Add irq flag to disable balancing for an interrupt

Add a flag so we can prevent the irq balancing of an interrupt.  Move the
bits, so we have room for more :)

Necessary for the ability to setup clocksources more flexible (e.g.  use the
different HPET channels per CPU)

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 5 insertions, 1 deletions

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index acc5d9fe462b..cd790ad0ae57 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -281,6 +281,10 @@ int setup_irq(unsigned int irq, struct irqaction *new)
         if (new->flags & IRQF_PERCPU)
                 desc->status |= IRQ_PER_CPU;
 #endif
+        /* Exclude IRQ from balancing */
+        if (new->flags & IRQF_NOBALANCING)
+                desc->status |= IRQ_NO_BALANCING;
+
         if (!shared) {
                 irq_chip_set_defaults(desc->chip);
 
diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
index 6d3be06e8ce6..bb44bc995d6e 100644
--- a/kernel/irq/proc.c
+++ b/kernel/irq/proc.c
@@ -55,7 +55,7 @@ static int irq_affinity_write_proc(struct file *file, const char __user *buffer,
         cpumask_t new_value, tmp;
 
         if (!irq_desc[irq].chip->set_affinity || no_irq_affinity ||
-                                CHECK_IRQ_PER_CPU(irq_desc[irq].status))
+            irq_balancing_disabled(irq))
                 return -EIO;
 
         err = cpumask_parse_user(buffer, count, new_value);