irqdomain: Always update revmap when setting up a virq

At irq_setup_virq() time all of the data needed to update the reverse
map is available, but the current code ignores it and relies upon the
slow path to insert revmap records.  This patch adds revmap updating
to the setup path so the slow path will no longer be necessary.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Rob Herring <rob.herring@calxeda.com>

arch/powerpc/sysdev/xics/xics-common.c

@@ -329,9 +329,6 @@ static int xics_host_map(struct irq_domain *h, unsigned int virq,
 
 	pr_devel("xics: map virq %d, hwirq 0x%lx\n", virq, hw);
 
-	/* Insert the interrupt mapping into the radix tree for fast lookup */
-	irq_radix_revmap_insert(xics_host, virq, hw);
-
 	/* They aren't all level sensitive but we just don't really know */
 	irq_set_status_flags(virq, IRQ_LEVEL);
 

kernel/irq/irqdomain.c

@@ -424,6 +424,18 @@ static int irq_setup_virq(struct irq_domain *domain, unsigned int virq,
 		return -1;
 	}
 
+	switch (domain->revmap_type) {
+	case IRQ_DOMAIN_MAP_LINEAR:
+		if (hwirq < domain->revmap_data.linear.size)
+			domain->revmap_data.linear.revmap[hwirq] = virq;
+		break;
+	case IRQ_DOMAIN_MAP_TREE:
+		mutex_lock(&revmap_trees_mutex);
+		irq_radix_revmap_insert(domain, virq, hwirq);
+		mutex_unlock(&revmap_trees_mutex);
+		break;
+	}
+
 	irq_clear_status_flags(virq, IRQ_NOREQUEST);
 
 	return 0;