Re: [PATCH mlx5-next v1 2/5] PCI: Add SR-IOV sysfs entry to read number of MSI-X vectors

[Leon Romanovsky <leon@kernel.org>]

On Mon, Jan 18, 2021 at 06:03:22PM +0100, Greg KH wrote:
> On Sun, Jan 10, 2021 at 05:07:24PM +0200, Leon Romanovsky wrote:
> > From: Leon Romanovsky <leonro@nvidia.com>
> >
> > Some SR-IOV capable devices provide an ability to configure specific
> > number of MSI-X vectors on their VF prior driver is probed on that VF.
> >
> > In order to make management easy, provide new read-only sysfs file that
> > returns a total number of possible to configure MSI-X vectors.
> >
> > cat /sys/bus/pci/devices/.../sriov_vf_total_msix
> >   = 0 - feature is not supported
> >   > 0 - total number of MSI-X vectors to consume by the VFs
> >
> > Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> > ---
> >  Documentation/ABI/testing/sysfs-bus-pci | 14 +++++++++++
> >  drivers/pci/iov.c                       | 31 +++++++++++++++++++++++++
> >  drivers/pci/pci.h                       |  3 +++
> >  include/linux/pci.h                     |  2 ++
> >  4 files changed, 50 insertions(+)
> >
> > diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
> > index 05e26e5da54e..64e9b700acc9 100644
> > --- a/Documentation/ABI/testing/sysfs-bus-pci
> > +++ b/Documentation/ABI/testing/sysfs-bus-pci
> > @@ -395,3 +395,17 @@ Description:
> >  		The file is writable if the PF is bound to a driver that
> >  		supports the ->sriov_set_msix_vec_count() callback and there
> >  		is no driver bound to the VF.
> > +
> > +What:		/sys/bus/pci/devices/.../sriov_vf_total_msix
> > +Date:		January 2021
> > +Contact:	Leon Romanovsky <leonro@nvidia.com>
> > +Description:
> > +		This file is associated with the SR-IOV PFs.
> > +		It returns a total number of possible to configure MSI-X
> > +		vectors on the enabled VFs.
> > +
> > +		The values returned are:
> > +		 * > 0 - this will be total number possible to consume by VFs,
> > +		 * = 0 - feature is not supported
> > +
> > +		If no SR-IOV VFs are enabled, this value will return 0.
> > diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
> > index 42c0df4158d1..0a6ddf3230fd 100644
> > --- a/drivers/pci/iov.c
> > +++ b/drivers/pci/iov.c
> > @@ -394,12 +394,22 @@ static ssize_t sriov_drivers_autoprobe_store(struct device *dev,
> >  	return count;
> >  }
> >
> > +static ssize_t sriov_vf_total_msix_show(struct device *dev,
> > +					struct device_attribute *attr,
> > +					char *buf)
> > +{
> > +	struct pci_dev *pdev = to_pci_dev(dev);
> > +
> > +	return sprintf(buf, "%d\n", pdev->sriov->vf_total_msix);
>
> Nit, please use sysfs_emit() for new sysfs files.

I'll do, thanks.

>
> thanks,
>
> greg k-h