On Wed, 2012-10-31 at 17:19 -0400, Donald Dutile wrote:
> Some implementations of SRIOV provide a capability structure
> value of TotalVFs that is greater than what the software can support.
> Provide a method to reduce the capability structure reported value
> to the value the driver can support.
> This ensures sysfs reports the current capability of the system,
> hardware and software.
> Example for its use: igb & ixgbe -- report 8 & 64 as TotalVFs,
> but drivers only support 7 & 63 maximum.
>
> Signed-off-by: Donald Dutile <ddutile@xxxxxxxxxx>
> ---
> drivers/pci/iov.c | 27 ++++++++++++++++++++++++++-
> drivers/pci/pci-sysfs.c | 10 ++++++++--
> drivers/pci/pci.h | 1 +
> include/linux/pci.h | 5 +++++
> 4 files changed, 40 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
> index aeccc91..98c3d37 100644
> --- a/drivers/pci/iov.c
> +++ b/drivers/pci/iov.c
> @@ -682,7 +682,6 @@ int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn)
>
> if (!dev->is_physfn)
> return -ENODEV;
> -
> return sriov_enable(dev, nr_virtfn);
> }
> EXPORT_SYMBOL_GPL(pci_enable_sriov);
This hunk doesn't belong in this patch.
> @@ -735,3 +734,29 @@ int pci_num_vf(struct pci_dev *dev)
> return dev->sriov->nr_virtfn;
> }
> EXPORT_SYMBOL_GPL(pci_num_vf);
> +
> +/**
> + * pci_sriov_set_totalvfs -- reduce the TotalVFs available
> + * @dev: the PCI PF device
> + * numvfs: number that should be used for TotalVFs supported
> + *
> + * Should be called from PF driver's probe routine with
> + * device's mutex held.
> + *
> + * Returns 0 if PF is an SRIOV-capable device and
> + * value of numvfs valid, otherwise -EINVAL
This says the only possible error is -EINVAL, but it can also return
-EIO! And the already-enabled case might be one that some drivers will
need to handle specially.
> + */
> +int pci_sriov_set_totalvfs(struct pci_dev *dev, u16 numvfs)
> +{
> + if (!dev || !dev->is_physfn || (numvfs > dev->sriov->total))
> + return -EINVAL;
> +
> + /* Shouldn't change if VFs already enabled */
> + if (dev->sriov->ctrl & PCI_SRIOV_CTRL_VFE)
> + return -EIO;
[...]
EBUSY seems a bit more appropriate.
Ben.
--
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.
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