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Date:   Fri, 28 Jun 2019 10:44:02 +0200
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Rajat Jain <rajatja@google.com>
Cc:     Bjorn Helgaas <helgaas@kernel.org>,
        linux-pci <linux-pci@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Rajat Jain <rajatxjain@gmail.com>
Subject: Re: PCI/AER sysfs files violate the rules of how sysfs works
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On Thu, Jun 27, 2019 at 05:56:59PM -0700, Rajat Jain wrote:
> 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.

Sounds good to me.

thanks,

greg k-h