linux-kernel - Re: [PATCH v4 12/16] libnvdimm, nfit: enable support for volatile ranges

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20170706021118.GA14468@lst.de>
Date:   Thu, 6 Jul 2017 04:11:18 +0200
From:   "hch@....de" <hch@....de>
To:     Dan Williams <dan.j.williams@...el.com>
Cc:     "Kani, Toshimitsu" <toshi.kani@....com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "hch@....de" <hch@....de>,
        "viro@...iv.linux.org.uk" <viro@...iv.linux.org.uk>,
        "x86@...nel.org" <x86@...nel.org>,
        "mawilcox@...rosoft.com" <mawilcox@...rosoft.com>,
        "linux-nvdimm@...ts.01.org" <linux-nvdimm@...ts.01.org>,
        "Knippers, Linda" <linda.knippers@....com>,
        "linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
        "jack@...e.cz" <jack@...e.cz>, jmoyer <jmoyer@...hat.com>,
        Johannes Thumshirn <jthumshirn@...e.de>
Subject: Re: [PATCH v4 12/16] libnvdimm, nfit: enable support for volatile
        ranges

On Wed, Jul 05, 2017 at 07:08:54PM -0700, Dan Williams wrote:
> [ adding Jeff, and Johannes ]
> 
> On Wed, Jul 5, 2017 at 6:17 PM, Kani, Toshimitsu <toshi.kani@....com> wrote:
> > On Wed, 2017-07-05 at 17:07 -0700, Dan Williams wrote:
> [..]
> >> We have symlinks in /dev/disk/by* to make it easier to identify
> >> storage devices, I think it makes sense to add udev rules for
> >> identifying volatile pmem and not try to differentiate this in the
> >> default kernel device name.
> >
> > I am not sure what might be a good way, but I am concerned because a
> > single block device naming do not represent both volatile and
> > persistent media today.
> 
> We do have time to changes this if we find out this is critical. Maybe
> it's best to ask Linux distro folks what would be easier for them?

I'm not really concerned about it, because SCSI devices for example
might not be persistent as well with ѕcsi_debug, target_core_rd or
volatile qemu devices.

That being said I really don't understand the purpose of these volatile
nfit ranges.  Are they seen in the wild?  If yes what's the use case?
If not why do we even need to support them?