PCI: Add for_each_pci_bridge() helper

The following pattern is often used:

  list_for_each_entry(dev, &bus->devices, bus_list) {
    if (pci_is_bridge(dev)) {
      ...
    }
  }

Add a for_each_pci_bridge() helper to make that code easier to write and
read by reducing indentation level.  It also saves one or few lines of code
in each occurrence.

Convert PCI core parts here at the same time.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
[bhelgaas: fold in http://lkml.kernel.org/r/20171013165352.25550-1-andriy.shevchenko@linux.intel.com]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

8 files changed, 23 insertions, 32 deletions

diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index 5ed2dca..5db6f18 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -462,18 +462,15 @@ static void enable_slot(struct acpiphp_slot *slot)
 	acpiphp_rescan_slot(slot);
 	max = acpiphp_max_busnr(bus);
 	for (pass = 0; pass < 2; pass++) {
-		list_for_each_entry(dev, &bus->devices, bus_list) {
+		for_each_pci_bridge(dev, bus) {
 			if (PCI_SLOT(dev->devfn) != slot->device)
 				continue;
 
-			if (pci_is_bridge(dev)) {
-				max = pci_scan_bridge(bus, dev, max, pass);
-				if (pass && dev->subordinate) {
-					check_hotplug_bridge(slot, dev);
-					pcibios_resource_survey_bus(dev->subordinate);
-					__pci_bus_size_bridges(dev->subordinate,
-							       &add_list);
-				}
+			max = pci_scan_bridge(bus, dev, max, pass);
+			if (pass && dev->subordinate) {
+				check_hotplug_bridge(slot, dev);
+				pcibios_resource_survey_bus(dev->subordinate);
+				__pci_bus_size_bridges(dev->subordinate, &add_list);
 			}
 		}
 	}
diff --git a/drivers/pci/hotplug/cpci_hotplug_pci.c b/drivers/pci/hotplug/cpci_hotplug_pci.c
index 80c8001..f616358 100644
--- a/drivers/pci/hotplug/cpci_hotplug_pci.c
+++ b/drivers/pci/hotplug/cpci_hotplug_pci.c
@@ -286,14 +286,11 @@ int cpci_configure_slot(struct slot *slot)
 	}
 	parent = slot->dev->bus;
 
-	list_for_each_entry(dev, &parent->devices, bus_list) {
-		if (PCI_SLOT(dev->devfn) != PCI_SLOT(slot->devfn))
-			continue;
-		if (pci_is_bridge(dev))
+	for_each_pci_bridge(dev, parent) {
+		if (PCI_SLOT(dev->devfn) == PCI_SLOT(slot->devfn))
 			pci_hp_add_bridge(dev);
 	}
 
-
 	pci_assign_unassigned_bridge_resources(parent->self);
 
 	pci_bus_add_devices(parent);
diff --git a/drivers/pci/hotplug/pciehp_pci.c b/drivers/pci/hotplug/pciehp_pci.c
index 19f30a9..c3af027 100644
--- a/drivers/pci/hotplug/pciehp_pci.c
+++ b/drivers/pci/hotplug/pciehp_pci.c
@@ -60,9 +60,8 @@ int pciehp_configure_device(struct slot *p_slot)
 		goto out;
 	}
 
-	list_for_each_entry(dev, &parent->devices, bus_list)
-		if (pci_is_bridge(dev))
-			pci_hp_add_bridge(dev);
+	for_each_pci_bridge(dev, parent)
+		pci_hp_add_bridge(dev);
 
 	pci_assign_unassigned_bridge_resources(bridge);
 	pcie_bus_configure_settings(parent);
diff --git a/drivers/pci/hotplug/shpchp_pci.c b/drivers/pci/hotplug/shpchp_pci.c
index f8cd3a2..ea63db5 100644
--- a/drivers/pci/hotplug/shpchp_pci.c
+++ b/drivers/pci/hotplug/shpchp_pci.c
@@ -61,10 +61,8 @@ int shpchp_configure_device(struct slot *p_slot)
 		goto out;
 	}
 
-	list_for_each_entry(dev, &parent->devices, bus_list) {
-		if (PCI_SLOT(dev->devfn) != p_slot->device)
-			continue;
-		if (pci_is_bridge(dev))
+	for_each_pci_bridge(dev, parent) {
+		if (PCI_SLOT(dev->devfn) == p_slot->device)
 			pci_hp_add_bridge(dev);
 	}
 
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index ff94b69..cdc2f83 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2421,10 +2421,8 @@ unsigned int pci_scan_child_bus(struct pci_bus *bus)
 	}
 
 	for (pass = 0; pass < 2; pass++)
-		list_for_each_entry(dev, &bus->devices, bus_list) {
-			if (pci_is_bridge(dev))
-				max = pci_scan_bridge(bus, dev, max, pass);
-		}
+		for_each_pci_bridge(dev, bus)
+			max = pci_scan_bridge(bus, dev, max, pass);
 
 	/*
 	 * Make sure a hotplug bridge has at least the minimum requested
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 958da7d..7ca0340 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -1921,10 +1921,9 @@ void pci_assign_unassigned_bus_resources(struct pci_bus *bus)
 					want additional resources */
 
 	down_read(&pci_bus_sem);
-	list_for_each_entry(dev, &bus->devices, bus_list)
-		if (pci_is_bridge(dev) && pci_has_subordinate(dev))
-				__pci_bus_size_bridges(dev->subordinate,
-							 &add_list);
+	for_each_pci_bridge(dev, bus)
+		if (pci_has_subordinate(dev))
+			__pci_bus_size_bridges(dev->subordinate, &add_list);
 	up_read(&pci_bus_sem);
 	__pci_bus_assign_resources(bus, &add_list, NULL);
 	BUG_ON(!list_empty(&add_list));
diff --git a/drivers/pcmcia/cardbus.c b/drivers/pcmcia/cardbus.c
index 4fe4cc4..5c01705 100644
--- a/drivers/pcmcia/cardbus.c
+++ b/drivers/pcmcia/cardbus.c
@@ -77,9 +77,8 @@ int __ref cb_alloc(struct pcmcia_socket *s)
 
 	max = bus->busn_res.start;
 	for (pass = 0; pass < 2; pass++)
-		list_for_each_entry(dev, &bus->devices, bus_list)
-			if (pci_is_bridge(dev))
-				max = pci_scan_bridge(bus, dev, max, pass);
+		for_each_pci_bridge(dev, bus)
+			max = pci_scan_bridge(bus, dev, max, pass);
 
 	/*
 	 * Size all resources below the CardBus controller.
diff --git a/include/linux/pci.h b/include/linux/pci.h
index f4f8ee5..3dbe947 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -596,6 +596,10 @@ static inline bool pci_is_bridge(struct pci_dev *dev)
 		dev->hdr_type == PCI_HEADER_TYPE_CARDBUS;
 }
 
+#define for_each_pci_bridge(dev, bus)				\
+	list_for_each_entry(dev, &bus->devices, bus_list)	\
+		if (!pci_is_bridge(dev)) {} else
+
 static inline struct pci_dev *pci_upstream_bridge(struct pci_dev *dev)
 {
 	dev = pci_physfn(dev);