x64, x2apic/intr-remap: generic irq migration support from process context

Generic infrastructure for migrating the irq from the process context in the
presence of CONFIG_GENERIC_PENDING_IRQ.

This will be used later for migrating irq in the presence of
interrupt-remapping.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: akpm@linux-foundation.org
Cc: arjan@linux.intel.com
Cc: andi@firstfloor.org
Cc: ebiederm@xmission.com
Cc: jbarnes@virtuousgeek.org
Cc: steiner@sgi.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 9 insertions, 1 deletions

diff --git a/include/linux/irq.h b/include/linux/irq.h
index 552e0ec269c9..c211984b55e5 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -62,6 +62,7 @@ typedef	void (*irq_flow_handler_t)(unsigned int irq,
 #define IRQ_MOVE_PENDING        0x00200000      /* need to re-target IRQ destination */
 #define IRQ_NO_BALANCING        0x00400000      /* IRQ is excluded from balancing */
 #define IRQ_SPURIOUS_DISABLED   0x00800000      /* IRQ was disabled by the spurious trap */
+#define IRQ_MOVE_PCNTXT 0x01000000      /* IRQ migration from process context */
 
 #ifdef CONFIG_IRQ_PER_CPU
 # define CHECK_IRQ_PER_CPU(var) ((var) & IRQ_PER_CPU)
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 46d6611a33bb..628b5572a7c2 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -87,7 +87,14 @@ int irq_set_affinity(unsigned int irq, cpumask_t cpumask)
         set_balance_irq_affinity(irq, cpumask);
 
 #ifdef CONFIG_GENERIC_PENDING_IRQ
-        set_pending_irq(irq, cpumask);
+        if (desc->status & IRQ_MOVE_PCNTXT) {
+                unsigned long flags;
+
+                spin_lock_irqsave(&desc->lock, flags);
+                desc->chip->set_affinity(irq, cpumask);
+                spin_unlock_irqrestore(&desc->lock, flags);
+        } else
+                set_pending_irq(irq, cpumask);
 #else
         desc->affinity = cpumask;
         desc->chip->set_affinity(irq, cpumask);