PCI/MSI: Register irq domain with specific token

When creating a PCI/MSI domain, tag it with DOMAIN_BUS_PCI_MSI so
that it can be looked-up using irq_find_matching_host().

Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: <linux-arm-kernel@lists.infradead.org>
Cc: Yijing Wang <wangyijing@huawei.com>
Cc: Ma Jun <majun258@huawei.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Duc Dang <dhdang@apm.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/1438091186-10244-3-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index cd4c78c..3aae7c9 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -1273,12 +1273,19 @@
 					     struct msi_domain_info *info,
 					     struct irq_domain *parent)
 {
+	struct irq_domain *domain;
+
 	if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
 		pci_msi_domain_update_dom_ops(info);
 	if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
 		pci_msi_domain_update_chip_ops(info);
 
-	return msi_create_irq_domain(node, info, parent);
+	domain = msi_create_irq_domain(node, info, parent);
+	if (!domain)
+		return NULL;
+
+	domain->bus_token = DOMAIN_BUS_PCI_MSI;
+	return domain;
 }
 
 /**