genirq: Provide !SMP stub for irq_set_affinity_notifier()

Instead of requiring each consumer of the IRQ affinity notifier to have
themselves be explicitly dependent on CONFIG_SMP, make the definition of
struct irq_affinity_notify to exist independently of that config option
and introduce a stub for irq_set_affinity_notifier() under non SMP
configuration.

Fixes: 2eacc23 ("net/mlx4_core: Enforce irq affinity changes
immediatly")

Signed-off-by: Eyal Perry <eyalpe@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Cc: Yevgeny Petrilin <yevgenyp@mellanox.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: David S. Miller <davem@davemloft.net>
Link: http://lkml.kernel.org/r/1400597820-30685-1-git-send-email-amirv@mellanox.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

include/linux/interrupt.h

@@ -199,6 +199,26 @@ extern int check_wakeup_irqs(void);
 static inline int check_wakeup_irqs(void) { return 0; }
 #endif
 
+/**
+ * struct irq_affinity_notify - context for notification of IRQ affinity changes
+ * @irq:		Interrupt to which notification applies
+ * @kref:		Reference count, for internal use
+ * @work:		Work item, for internal use
+ * @notify:		Function to be called on change.  This will be
+ *			called in process context.
+ * @release:		Function to be called on release.  This will be
+ *			called in process context.  Once registered, the
+ *			structure must only be freed when this function is
+ *			called or later.
+ */
+struct irq_affinity_notify {
+	unsigned int irq;
+	struct kref kref;
+	struct work_struct work;
+	void (*notify)(struct irq_affinity_notify *, const cpumask_t *mask);
+	void (*release)(struct kref *ref);
+};
+
 #if defined(CONFIG_SMP)
 
 extern cpumask_var_t irq_default_affinity;
@@ -242,26 +262,6 @@ extern int irq_select_affinity(unsigned int irq);
 
 extern int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m);
 
-/**
- * struct irq_affinity_notify - context for notification of IRQ affinity changes
- * @irq:		Interrupt to which notification applies
- * @kref:		Reference count, for internal use
- * @work:		Work item, for internal use
- * @notify:		Function to be called on change.  This will be
- *			called in process context.
- * @release:		Function to be called on release.  This will be
- *			called in process context.  Once registered, the
- *			structure must only be freed when this function is
- *			called or later.
- */
-struct irq_affinity_notify {
-	unsigned int irq;
-	struct kref kref;
-	struct work_struct work;
-	void (*notify)(struct irq_affinity_notify *, const cpumask_t *mask);
-	void (*release)(struct kref *ref);
-};
-
 extern int
 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify);
 
@@ -284,6 +284,12 @@ static inline int irq_set_affinity_hint(unsigned int irq,
 {
 	return -EINVAL;
 }
+
+static inline int
+irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
+{
+	return 0;
+}
 #endif /* CONFIG_SMP */
 
 /*