On 2012-9-12 7:22, Bjorn Helgaas wrote:

On Tue, Aug 7, 2012 at 10:10 AM, Jiang Liu [off-list ref] wrote:

quoted

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 <redacted>
---
 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);
+}

Are these left over from previous work?  I don't see any reference to
them elsewhere in your patch series.

Hi Bjorn
	Eagle eyes! Yes, it's left from previous work and I have changed to
other mechanism for root bus locks.
	--Gerry

quoted

 /*
  * 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

.