[PATCH] irq: Add compiling definition of irq_thread_check_affinity for !CONFIG_SMP

[Kevin Winchester <kjwinchester@gmail.com>]

The addition and use of irq_thread_check_affinity neglected the fact
that struct irq_desc does not have an affinity member when CONFIG_SMP=n.

Fix this by adding an empty definition of the method for !SMP.

Signed-off-by: Kevin Winchester <kjwinchester@gmail.com>
---

I'll try not to be lazy and send a real patch.  Please let me know if
I've done it wrong.

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index f0de36f..82f01c8 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -190,11 +190,46 @@ int irq_select_affinity_usr(unsigned int irq)
 	return ret;
 }
 
+/*
+ * Check whether we need to change the affinity of the interrupt thread.
+ */
+static void
+irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
+{
+	cpumask_var_t mask;
+
+	if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
+		return;
+
+	/*
+	 * In case we are out of memory we set IRQTF_AFFINITY again and
+	 * try again next time
+	 */
+	if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
+		set_bit(IRQTF_AFFINITY, &action->thread_flags);
+		return;
+	}
+
+	spin_lock_irq(&desc->lock);
+	cpumask_copy(mask, desc->affinity);
+	spin_unlock_irq(&desc->lock);
+
+	set_cpus_allowed_ptr(current, mask);
+	free_cpumask_var(mask);
+}
+
 #else
+
 static inline int setup_affinity(unsigned int irq, struct irq_desc *desc)
 {
 	return 0;
 }
+
+static void
+irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
+{
+}
+
 #endif
 
 void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
@@ -452,34 +487,6 @@ static int irq_wait_for_interrupt(struct irqaction *action)
 }
 
 /*
- * Check whether we need to change the affinity of the interrupt thread.
- */
-static void
-irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
-{
-	cpumask_var_t mask;
-
-	if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
-		return;
-
-	/*
-	 * In case we are out of memory we set IRQTF_AFFINITY again and
-	 * try again next time
-	 */
-	if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
-		set_bit(IRQTF_AFFINITY, &action->thread_flags);
-		return;
-	}
-
-	spin_lock_irq(&desc->lock);
-	cpumask_copy(mask, desc->affinity);
-	spin_unlock_irq(&desc->lock);
-
-	set_cpus_allowed_ptr(current, mask);
-	free_cpumask_var(mask);
-}
-
-/*
  * Interrupt handler thread
  */
 static int irq_thread(void *data)