3 files changed, 16 insertions, 1 deletions

diff --git a/include/linux/irq.h b/include/linux/irq.h
index f04ba20712a2..60f8bc78a35a 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -221,6 +221,17 @@ extern void note_interrupt(unsigned int irq, irq_desc_t *desc,
 extern int can_request_irq(unsigned int irq, unsigned long irqflags);
 
 extern void init_irq_proc(void);
+
+#ifdef CONFIG_AUTO_IRQ_AFFINITY
+extern int select_smp_affinity(unsigned int irq);
+#else
+static inline int
+select_smp_affinity(unsigned int irq)
+{
+        return 1;
+}
+#endif
+
 #endif
 
 extern hw_irq_controller no_irq_type;  /* needed in every arch ? */
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 81c49a4d679e..97d5559997d2 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -366,6 +366,8 @@ int request_irq(unsigned int irq,
         action->next = NULL;
         action->dev_id = dev_id;
 
+        select_smp_affinity(irq);
+
         retval = setup_irq(irq, action);
         if (retval)
                 kfree(action);
diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
index f26e534c6585..8a64a4844cde 100644
--- a/kernel/irq/proc.c
+++ b/kernel/irq/proc.c
@@ -68,7 +68,9 @@ static int irq_affinity_write_proc(struct file *file, const char __user *buffer,
          */
         cpus_and(tmp, new_value, cpu_online_map);
         if (cpus_empty(tmp))
-                return -EINVAL;
+                /* Special case for empty set - allow the architecture
+                   code to set default SMP affinity. */
+                return select_smp_affinity(irq) ? -EINVAL : full_count;
 
         proc_set_irq_affinity(irq, new_value);