powerpc: Add virq_is_host to reduce virq_to_host usage

Some irq_host implementations are using virq_to_host to check if
they are the irq_host for a virtual irq.  To allow us to make space
versus time tradeoffs, replace this usage with an assertive
virq_is_host that confirms or denies the irq is associated with the
given irq_host.

Signed-off-by: Milton Miller <miltonm@bga.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

3 files changed, 8 insertions, 1 deletions

diff --git a/arch/powerpc/include/asm/irq.h b/arch/powerpc/include/asm/irq.h
index 6f4a3efb59a9..a65d1702643b 100644
--- a/arch/powerpc/include/asm/irq.h
+++ b/arch/powerpc/include/asm/irq.h
@@ -128,6 +128,7 @@ struct irq_host {
 struct irq_data;
 extern irq_hw_number_t irqd_to_hwirq(struct irq_data *d);
 extern irq_hw_number_t virq_to_hw(unsigned int virq);
+extern bool virq_is_host(unsigned int virq, struct irq_host *host);
 extern struct irq_host *virq_to_host(unsigned int virq);
 
 /**
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 0715a09a4101..73cf29078fef 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -510,6 +510,12 @@ irq_hw_number_t virq_to_hw(unsigned int virq)
 }
 EXPORT_SYMBOL_GPL(virq_to_hw);
 
+bool virq_is_host(unsigned int virq, struct irq_host *host)
+{
+        return irq_map[virq].host == host;
+}
+EXPORT_SYMBOL_GPL(virq_is_host);
+
 struct irq_host *virq_to_host(unsigned int virq)
 {
         return irq_map[virq].host;
diff --git a/arch/powerpc/sysdev/xics/xics-common.c b/arch/powerpc/sysdev/xics/xics-common.c
index 43b2a791e204..445c5a01b766 100644
--- a/arch/powerpc/sysdev/xics/xics-common.c
+++ b/arch/powerpc/sysdev/xics/xics-common.c
@@ -213,7 +213,7 @@ void xics_migrate_irqs_away(void)
                 /* We can't set affinity on ISA interrupts */
                 if (virq < NUM_ISA_INTERRUPTS)
                         continue;
-                if (virq_to_host(virq) != xics_host)
+                if (!virq_is_host(virq, xics_host))
                         continue;
                 irq = (unsigned int)virq_to_hw(virq);
                 /* We need to get IPIs still. */