quoted

+	host = kzalloc(sizeof(*host), GFP_KERNEL);
+	if (!host)
+		return NULL;
+
+	host->busnum = bus;
+	host->domain = domain;
+	/* If support CONFIG_PCI_DOMAINS_GENERIC, use
+	 * pci_host_assign_domain_nr() to assign domain
+	 * number instead PCI_DOMAIN(db).
+	 */

Follow the normal Linux comment style:

	host->domain = domain;

	/*
	 * If we support ...
	 */

OK.

quoted

+	pci_host_assign_domain_nr(host);
+

...

quoted

 
+struct pci_host_bridge *pci_create_host_bridge(
+		struct device *parent, u32 dombus, struct list_head *resources);
+void pci_free_host_bridge(struct pci_host_bridge *host);

A later patch adds another declaration and a blank line here.  If you want
the blank line, add it here, when you're adding the first declarations in
this section.

OK.

quoted

 #endif /* DRIVERS_PCI_H */

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 3d6befd..27ec612 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c

@@ -503,31 +503,6 @@ static struct pci_bus *pci_alloc_bus(struct pci_bus *parent)
 	return b;
 }

...

quoted

 struct pci_host_bridge {
 	u16	domain;
+	u16 busnum;

Why do we need this?  host_bridge->bus->number and
host_bridge->bus->busn_res.start both already contain the same information,
and I hate to add a third place.  I know pci_create_host_bridge() doesn't
have a struct pci_bus at the point where you initialize busnum, but it does
have the resource list, which contains the bus number range.

Hmm, I will try to remove it, I put it here because when call pci_create_root_bus(),
I could only pass the pci_host_bridge_ops, don't need to provide the bus number,
pci_scan_root_bus() may lack the bus number resource at that time.
But I think fix it is not a hard job, I will rework it, thanks.

quoted

 	struct device dev;
 	struct pci_bus *bus;		/* root bus */
 	struct list_head windows;	/* resource_entry */
-- 
1.7.1

.

-- 
Thanks!
Yijing