On Wed, Nov 6, 2013 at 12:46 PM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote:
> Oh, I see. The problem is when VF is on a virtual bus and the
> corresponding PF is on a root bus. Then we have:
>
> pci_is_root_bus(VF) == false
> pci_upstream_bridge(VF) == pci_upstream_bridge(PF)
> pci_uptream_bridge(PF) == NULL
>
> I guess that's what your suggestion about "caching the return from
> pci_upstream_bridge()" was about. Like this:
Yes.
For the two patches,
Acked-by: Yinghai Lu <yinghai@xxxxxxxxxx>
>
>
> commit 21ea57bf1311f7a8d1b755d355322a1f077fccb7
> Author: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Date: Wed Nov 6 10:11:48 2013 -0700
>
> PCI: Add pci_upstream_bridge()
>
> This adds a pci_upstream_bridge() interface to find the PCI-to-PCI bridge
> upstream from a device. This is typically just "dev->bus->self", but in
> the case of a VF on a virtual bus, we have to start from the corresponding
> PF. Returns NULL if there is no upstream PCI bridge, i.e., if the device
> is on a root bus.
>
> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
>
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index d3a888a..835ec7b 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -480,6 +480,15 @@ static inline bool pci_is_root_bus(struct pci_bus *pbus)
> return !(pbus->parent);
> }
>
> +static inline struct pci_dev *pci_upstream_bridge(struct pci_dev *dev)
> +{
> + dev = pci_physfn(dev);
> + if (pci_is_root_bus(dev->bus))
> + return NULL;
> +
> + return dev->bus->self;
> +}
> +
> #ifdef CONFIG_PCI_MSI
> static inline bool pci_dev_msi_enabled(struct pci_dev *pci_dev)
> {
> commit bca690ab580d5c0c4a0c7201f3c42057288add8b
> Author: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Date: Wed Nov 6 10:00:51 2013 -0700
>
> PCI: Enable upstream bridges even for VFs on virtual buses
>
> Previously we enabled the upstream PCI-to-PCI bridge only when
> "dev->bus->self != NULL". In the case of a VF on a virtual bus, where
> "bus->self == NULL", we didn't enable the upstream bridge.
>
> This fixes that by enabling the upstream bridge of the PF corresponding to
> the VF.
>
> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index ac40f90..d3ed931 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -1148,12 +1148,12 @@ int pci_reenable_device(struct pci_dev *dev)
>
> static void pci_enable_bridge(struct pci_dev *dev)
> {
> + struct pci_dev *bridge;
> int retval;
>
> - if (!dev)
> - return;
> -
> - pci_enable_bridge(dev->bus->self);
> + bridge = pci_upstream_bridge(dev);
> + if (bridge)
> + pci_enable_bridge(bridge);
>
> if (pci_is_enabled(dev)) {
> if (!dev->is_busmaster)
> @@ -1170,6 +1170,7 @@ static void pci_enable_bridge(struct pci_dev *dev)
>
> static int pci_enable_device_flags(struct pci_dev *dev, unsigned long flags)
> {
> + struct pci_dev *bridge;
> int err;
> int i, bars = 0;
>
> @@ -1188,7 +1189,9 @@ static int pci_enable_device_flags(struct pci_dev *dev, unsigned long flags)
> if (atomic_inc_return(&dev->enable_cnt) > 1)
> return 0; /* already enabled */
>
> - pci_enable_bridge(dev->bus->self);
> + bridge = pci_upstream_bridge(dev);
> + if (bridge)
> + pci_enable_bridge(bridge);
>
> /* only skip sriov related */
> for (i = 0; i <= PCI_ROM_RESOURCE; i++)
--
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