linux-kernel - [PATCH 1/2] pciehp: remove redundancy in bridge resource allocation

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Date:	Wed, 25 Nov 2009 20:25:41 +0900
From:	Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>
To:	Yinghai Lu <yinghai@...nel.org>
CC:	Jesse Barnes <jbarnes@...tuousgeek.org>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Alex Chiang <achiang@...com>,
	Bjorn Helgaas <bjorn.helgaas@...com>,
	Ingo Molnar <mingo@...e.hu>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
	Ivan Kokshaysky <ink@...assic.park.msu.ru>
Subject: [PATCH 1/2] pciehp: remove redundancy in bridge resource allocation

Current pciehp driver configures bridge's child bus each time the
bridge is found on the hot-added PCIe adapter card. It is redundant
and strange because pciehp tryies to add devices on the child bus
before adding its parent bridge. It should be done at one time on the
slot's parent bus.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>

---
 drivers/pci/hotplug/pciehp_pci.c |   28 +++++++++++++---------------
 1 file changed, 13 insertions(+), 15 deletions(-)

Index: 20091125/drivers/pci/hotplug/pciehp_pci.c
===================================================================
--- 20091125.orig/drivers/pci/hotplug/pciehp_pci.c
+++ 20091125/drivers/pci/hotplug/pciehp_pci.c
@@ -34,30 +34,26 @@
 #include "../pci.h"
 #include "pciehp.h"
 
-static int __ref pciehp_add_bridge(struct pci_dev *dev)
+static void __ref pciehp_scan_bridge(struct pci_dev *dev)
 {
 	struct pci_bus *parent = dev->bus;
-	int pass, busnr, start = parent->secondary;
-	int end = parent->subordinate;
+	int pass, busnr, start, end;
 
+	start = parent->secondary;
+	end = parent->subordinate;
 	for (busnr = start; busnr <= end; busnr++) {
 		if (!pci_find_bus(pci_domain_nr(parent), busnr))
 			break;
 	}
+
 	if (busnr-- > end) {
 		err("No bus number available for hot-added bridge %s\n",
-				pci_name(dev));
-		return -1;
+		    pci_name(dev));
+		return;
 	}
+
 	for (pass = 0; pass < 2; pass++)
 		busnr = pci_scan_bridge(parent, dev, busnr, pass);
-	if (!dev->subordinate)
-		return -1;
-	pci_bus_size_bridges(dev->subordinate);
-	pci_bus_assign_resources(parent);
-	pci_enable_bridges(parent);
-	pci_bus_add_devices(parent);
-	return 0;
 }
 
 int pciehp_configure_device(struct slot *p_slot)
@@ -93,14 +89,16 @@ int pciehp_configure_device(struct slot 
 			continue;
 		}
 		if ((dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) ||
-				(dev->hdr_type == PCI_HEADER_TYPE_CARDBUS)) {
-			pciehp_add_bridge(dev);
-		}
+		    (dev->hdr_type == PCI_HEADER_TYPE_CARDBUS))
+			pciehp_scan_bridge(dev);
+
 		pci_configure_slot(dev);
 		pci_dev_put(dev);
 	}
 
+	pci_bus_size_bridges(parent);
 	pci_bus_assign_resources(parent);
+	pci_enable_bridges(parent);
 	pci_bus_add_devices(parent);
 	return 0;
 }

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