linux-kernel - Re: [Linux-kernel-mentees] [PATCH v2 2/3] PCI: sysfs: Change permissions from symbolic to octal

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Date:   Wed, 14 Aug 2019 09:53:24 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Bjorn Helgaas <helgaas@...nel.org>
Cc:     Kelsey Skunberg <skunberg.kelsey@...il.com>,
        linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-kernel-mentees@...ts.linuxfoundation.org,
        Bodong Wang <bodong@...lanox.com>,
        Donald Dutile <ddutile@...hat.com>
Subject: Re: [Linux-kernel-mentees] [PATCH v2 2/3] PCI: sysfs: Change
 permissions from symbolic to octal

On Wed, Aug 14, 2019 at 12:38:46AM -0500, Bjorn Helgaas wrote:
> [+cc Bodong, Don, Greg for permission question]
> 
> On Tue, Aug 13, 2019 at 02:45:12PM -0600, Kelsey Skunberg wrote:
> > Symbolic permissions such as "(S_IWUSR | S_IWGRP)" are not
> > preferred and octal permissions should be used instead. Change all
> > symbolic permissions to octal permissions.
> > 
> > Example of old:
> > 
> > "(S_IWUSR | S_IWGRP)"
> > 
> > Example of new:
> > 
> > "0220"
> 
> 
> >  static DEVICE_ATTR_RO(sriov_totalvfs);
> > -static DEVICE_ATTR(sriov_numvfs, (S_IRUGO | S_IWUSR | S_IWGRP),
> > -				  sriov_numvfs_show, sriov_numvfs_store);
> > +static DEVICE_ATTR(sriov_numvfs, 0664, sriov_numvfs_show, sriov_numvfs_store);
> >  static DEVICE_ATTR_RO(sriov_offset);
> >  static DEVICE_ATTR_RO(sriov_stride);
> >  static DEVICE_ATTR_RO(sriov_vf_device);
> > -static DEVICE_ATTR(sriov_drivers_autoprobe, (S_IRUGO | S_IWUSR | S_IWGRP),
> > -		   sriov_drivers_autoprobe_show, sriov_drivers_autoprobe_store);
> > +static DEVICE_ATTR(sriov_drivers_autoprobe, 0664, sriov_drivers_autoprobe_show,
> > +		   sriov_drivers_autoprobe_store);
> 
> Greg noticed that sriov_numvfs and sriov_drivers_autoprobe have
> "unusual" permissions.  These were added by:
> 
>   0e7df22401a3 ("PCI: Add sysfs sriov_drivers_autoprobe to control VF driver binding")
>   1789382a72a5 ("PCI: SRIOV control and status via sysfs")
> 
> Kelsey's patch correctly preserves the existing permissions, but we
> should double-check that they are the permissions they want, and
> possibly add a comment about why they're different from the rest.

I agree.  And if those permissions are ok, please put a HUGE comment in
here saying why they are what they are and why they need to stay that
way so we don't have this conversation again in a few years :)

thanks,

greg k-h