On Thu, Jan 04, 2018 at 05:09:58PM -0600, Stuart Hayes wrote:
>
>
> On 1/3/2018 6:08 PM, Bjorn Helgaas wrote:
> > Hi Stuart,
> >
> > Please run "git log --oneline drivers/pci/pci-sysfs.c" and follow the
> > convention.
> >
>
> Bjorn,
>
> Is the problem just with the subject line (i.e., it should be something
> like "PCI: Expose ari_enabled...")?
Yep, exactly. I don't have any issue with the patch itself; I just
like the logs to be consistent to make them easier to read because I
spend a lot of time reading them :)
> I'm happy to fix, I just want to make sure I understand the problem so I
> get it right next time.
> > On Wed, Jan 03, 2018 at 10:36:46AM -0600, Stuart Hayes wrote:
> >> Some multifunction PCI devices with more than 8 functions use "alternative
> >> routing-ID interpretation" (ARI), which means the 8-bit device/function
> >> number field will be interpreted as 8 bits specifying the function number
> >> (the device number is 0 implicitly), rather than the upper 5 bits
> >> specifying the device number and the lower 3 bits specifying the function
> >> number. The kernel can enable and use this.
> >>
> >> Expose in a sysfs attribute whether the kernel has enabled ARI, so that a
> >> program in userspace won't have to parse PCI devices and PCI configuration
> >> space to figure out if it is enabled. This will allow better predictable
> >> network naming using PCI function numbers without using PCI bus or device
> >> numbers, which is desirable because bus and device numbers can change with
> >> system configuration but function numbers will not.
> >>
> >> Signed-off-by: Stuart Hayes <stuart.w.hayes@xxxxxxxxx>
> >> ---
> >>
> >> --- linux-4.15-rc6/drivers/pci/pci-sysfs.c.orig 2017-12-31 17:47:43.000000000 -0500
> >> +++ linux-4.15-rc6/drivers/pci/pci-sysfs.c 2018-01-02 13:58:23.372928377 -0500
> >> @@ -278,6 +278,16 @@ static ssize_t subordinate_bus_number_sh
> >> }
> >> static DEVICE_ATTR_RO(subordinate_bus_number);
> >>
> >> +static ssize_t ari_enabled_show(struct device *dev,
> >> + struct device_attribute *attr,
> >> + char *buf)
> >> +{
> >> + struct pci_dev *pci_dev = to_pci_dev(dev);
> >> +
> >> + return sprintf(buf, "%u\n", pci_ari_enabled(pci_dev->bus));
> >> +}
> >> +static DEVICE_ATTR_RO(ari_enabled);
> >> +
> >> static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
> >> char *buf)
> >> {
> >> @@ -786,6 +796,7 @@ static struct attribute *pci_dev_attrs[]
> >> &dev_attr_devspec.attr,
> >> #endif
> >> &dev_attr_driver_override.attr,
> >> + &dev_attr_ari_enabled.attr,
> >> NULL,
> >> };
> >>
> >>
> >>
> >> ---
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> >>
