linux-kernel - [RFC PATCH v1 19/22] PCI/x86: enable PCI bus lock mechanism for x86 platforms

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Date:	Wed,  8 Aug 2012 00:10:59 +0800
From:	Jiang Liu <liuj97@...il.com>
To:	Bjorn Helgaas <bhelgaas@...gle.com>,
	Don Dutile <ddutile@...hat.com>,
	Yinghai Lu <yinghai@...nel.org>,
	Greg KH <gregkh@...uxfoundation.org>,
	Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>
Cc:	Jiang Liu <jiang.liu@...wei.com>,
	Taku Izumi <izumi.taku@...fujitsu.com>,
	"Rafael J . Wysocki" <rjw@...k.pl>,
	Yijing Wang <wangyijing@...wei.com>,
	Xinwei Hu <huxinwei@...wei.com>, linux-kernel@...r.kernel.org,
	linux-pci@...r.kernel.org, Jiang Liu <liuj97@...il.com>
Subject: [RFC PATCH v1 19/22] PCI/x86: enable PCI bus lock mechanism for x86 platforms

This patch turns on PCI bus lock mechanism for x86 platforms. It also
enhances x86 specific PCI implementation to support PCI bus lock.

Signed-off-by: Jiang Liu <liuj97@...il.com>
---
 arch/x86/pci/acpi.c   |    6 +++++-
 arch/x86/pci/common.c |   12 ++++++++++++
 drivers/pci/Kconfig   |    3 +--
 3 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
index 2bb885a..c68dbdf 100644
--- a/arch/x86/pci/acpi.c
+++ b/arch/x86/pci/acpi.c
@@ -414,7 +414,8 @@ struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_pci_root *root)
 	 * Maybe the desired pci bus has been already scanned. In such case
 	 * it is unnecessary to scan the pci bus with the given domain,busnum.
 	 */
-	bus = pci_find_bus(domain, busnum);
+	bus = __pci_get_and_lock_bus(domain, busnum,
+				     PCI_BUS_STATE_STOPPING - 1);
 	if (bus) {
 		/*
 		 * If the desired bus exits, the content of bus->sysdata will
@@ -449,6 +450,7 @@ struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_pci_root *root)
 			pci_free_resource_list(&resources);
 			__release_pci_root_info(info);
 		}
+		pci_bus_get(bus);
 	}
 
 	/* After the PCI-E bus has been walked and all devices discovered,
@@ -475,6 +477,8 @@ struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_pci_root *root)
 #endif
 	}
 
+	pci_unlock_and_put_bus(bus);
+
 	return bus;
 }
 
diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
index 0ad990a..8b7ae63 100644
--- a/arch/x86/pci/common.c
+++ b/arch/x86/pci/common.c
@@ -667,6 +667,18 @@ struct pci_bus * __devinit pci_scan_bus_with_sysdata(int busno)
 	return pci_scan_bus_on_node(busno, &pci_root_ops, -1);
 }
 
+static DEFINE_MUTEX(pci_root_bus_mutex);
+
+void arch_pci_lock_host_bridge_hotplug(void)
+{
+	mutex_lock(&pci_root_bus_mutex);
+}
+
+void arch_pci_unlock_host_bridge_hotplug(void)
+{
+	mutex_unlock(&pci_root_bus_mutex);
+}
+
 /*
  * NUMA info for PCI busses
  *
diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index a6df8b1..1bbe924 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -122,5 +122,4 @@ config PCI_LABEL
 	select NLS
 
 config PCI_BUS_LOCK
-	bool
-	default n
+	def_bool y if X86
-- 
1.7.9.5

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