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>

6 files changed, 17 insertions, 29 deletions

diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index 5ed2dcaa8e27..5db6f1839dad 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 80c80017197d..f616358fa938 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 19f30a9f461d..c3af027ee1a6 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 f8cd3a27e351..ea63db58b4b1 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 ff94b69738a8..cdc2f83c11c5 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 958da7db9033..7ca03407404c 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));