irq/apic: Use config_enabled(CONFIG_SMP) checks to clean up irq_set_affinity() for UP

Move the ->irq_set_affinity() routines out of the #ifdef CONFIG_SMP
sections and use config_enabled(CONFIG_SMP) checks inside those
routines. Thus making those routines simple null stubs for
!CONFIG_SMP and retaining those routines with no additional
runtime overhead for CONFIG_SMP kernels.

Cleans up the ifdef CONFIG_SMP in and around routines related to
irq_set_affinity in io_apic and irq_remapping subsystems.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: torvalds@linux-foundation.org
Cc: joerg.roedel@amd.com
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Link: http://lkml.kernel.org/r/1339723729.3475.63.camel@sbsiddha-desk.sc.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
index 853902a..e0b18f3 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -902,7 +902,6 @@
 	return 0;
 }
 
-#ifdef CONFIG_SMP
 /*
  * Migrate the IO-APIC irq in the presence of intr-remapping.
  *
@@ -926,6 +925,9 @@
 	struct irte irte;
 	int err;
 
+	if (!config_enabled(CONFIG_SMP))
+		return -EINVAL;
+
 	if (!cpumask_intersects(mask, cpu_online_mask))
 		return -EINVAL;
 
@@ -963,7 +965,6 @@
 	cpumask_copy(data->affinity, mask);
 	return 0;
 }
-#endif
 
 static void intel_compose_msi_msg(struct pci_dev *pdev,
 				  unsigned int irq, unsigned int dest,
@@ -1065,9 +1066,7 @@
 	.reenable		= reenable_irq_remapping,
 	.enable_faulting	= enable_drhd_fault_handling,
 	.setup_ioapic_entry	= intel_setup_ioapic_entry,
-#ifdef CONFIG_SMP
 	.set_affinity		= intel_ioapic_set_affinity,
-#endif
 	.free_irq		= free_irte,
 	.compose_msi_msg	= intel_compose_msi_msg,
 	.msi_alloc_irq		= intel_msi_alloc_irq,