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From:   Rajat Jain <rajatja@google.com>
Date:   Thu, 27 Jun 2019 17:56:59 -0700
Message-ID: <CACK8Z6FXS3VoaqxmwXCR2vnp-TSE5zGMi6Zt1w_LxskTguMw=Q@mail.gmail.com>
Subject: Re: PCI/AER sysfs files violate the rules of how sysfs works
To:     Bjorn Helgaas <helgaas@kernel.org>
Cc:     Greg KH <gregkh@linuxfoundation.org>,
        linux-pci <linux-pci@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Rajat Jain <rajatxjain@gmail.com>
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On Fri, Jun 21, 2019 at 7:15 AM Bjorn Helgaas <helgaas@kernel.org> wrote:
>
> On Fri, Jun 21, 2019 at 09:29:11AM +0200, Greg KH wrote:
> > Hi,
> >
> > When working on some documentation scripts to show the
> > Documentation/ABI/ files in an automated way, I ran across this "gem" of
> > a sysfs file: Documentation/ABI/testing/sysfs-bus-pci-devices-aer_stats
> >
> > In it you describe how the files
> > /sys/bus/pci/devices/<dev>/aer_dev_correctable and
> > /sys/bus/pci/devices/<dev>/aer_dev_fatal and
> > /sys/bus/pci/devices/<dev>/aer_dev_nonfatal
> > all display a bunch of text on multiple lines.
> >
> > This violates the "one value per sysfs file" rule, and should never have
> > been merged as-is :(
> >
> > Please fix it up to be a lot of individual files if your really need all
> > of those different values.
>
> Sorry about that.  Do you think we're safe in changing the sysfs ABI
> by removing the original files and replacing them with new, better
> ones?  This is pretty new and hopefully not widely used yet.

Hi Bjorn / Greg,

I'm thinking of having a named group  for AER stats so that all the
individual counter attributes are put under a subdirectory (called
"aer_stats") in the sysfs, instead of cluttering the PCI device
directory. I expect to have the following counters in there:

dev_err_corr_<correctible_error_name>  (Total 8 such files)
dev_err_fatal_<fatal_error_name> (Total 17 Such files)
dev_err_nonfatal_<fatal_error_name> (Total 17 Such files)

dev_total_err_corr (1file)
dev_total_err_fatal (1file)
dev_total_err_nonfatal (1file)

rootport_total_err_corr (1file - only for rootports)
rootport_total_err_fatal (1file - only for rootports)
rootport_total_err_nonfatal (1file - only for rootports)

Please let me know if this sounds ok.

Thanks & Best Regards,

Rajat

>
> Bjorn