Re: [RFC PATCH v1 19/22] PCI/x86: enable PCI bus lock mechanism forx86 platforms

From: Bjorn Helgaas
Date: Tue Sep 11 2012 - 19:22:46 EST


On Tue, Aug 7, 2012 at 10:10 AM, Jiang Liu <liuj97@xxxxxxxxx> wrote:
> 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@xxxxxxxxx>
> ---
> 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.

> /*
> * 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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