PCI: Remove pci_bus_b() and use list_for_each_entry() directly

Replace list_for_each() with list_for_each_entry(), which means we no
longer need pci_bus_b() and can remove it.
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/pci.c

@@ -108,12 +108,12 @@ static bool pcie_ari_disabled;
  */
 unsigned char pci_bus_max_busnr(struct pci_bus* bus)
 {
-	struct list_head *tmp;
+	struct pci_bus *tmp;
 	unsigned char max, n;
 
 	max = bus->busn_res.end;
-	list_for_each(tmp, &bus->children) {
-		n = pci_bus_max_busnr(pci_bus_b(tmp));
+	list_for_each_entry(tmp, &bus->children, node) {
+		n = pci_bus_max_busnr(tmp);
 		if(n > max)
 			max = n;
 	}

drivers/pci/search.c

@@ -54,14 +54,14 @@ pci_find_upstream_pcie_bridge(struct pci_dev *pdev)
 
 static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr)
 {
-	struct pci_bus* child;
-	struct list_head *tmp;
+	struct pci_bus *child;
+	struct pci_bus *tmp;
 
 	if(bus->number == busnr)
 		return bus;
 
-	list_for_each(tmp, &bus->children) {
-		child = pci_do_find_bus(pci_bus_b(tmp), busnr);
+	list_for_each_entry(tmp, &bus->children, node) {
+		child = pci_do_find_bus(tmp, busnr);
 		if(child)
 			return child;
 	}
@@ -111,7 +111,7 @@ pci_find_next_bus(const struct pci_bus *from)
 	down_read(&pci_bus_sem);
 	n = from ? from->node.next : pci_root_buses.next;
 	if (n != &pci_root_buses)
-		b = pci_bus_b(n);
+		b = list_entry(n, struct pci_bus, node);
 	up_read(&pci_bus_sem);
 	return b;
 }

include/linux/pci.h

@@ -461,7 +461,6 @@ struct pci_bus {
 	unsigned int		is_added:1;
 };
 
-#define pci_bus_b(n)	list_entry(n, struct pci_bus, node)
 #define to_pci_bus(n)	container_of(n, struct pci_bus, dev)
 
 /*