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    SubjectRE: [PATCH v2 0/2] Simplify mtty driver and mdev core
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    > -----Original Message-----
    > From: Cornelia Huck <cohuck@redhat.com>
    > Sent: Tuesday, August 20, 2019 11:25 PM
    > To: Alex Williamson <alex.williamson@redhat.com>
    > Cc: Parav Pandit <parav@mellanox.com>; Jiri Pirko <jiri@mellanox.com>;
    > David S . Miller <davem@davemloft.net>; Kirti Wankhede
    > <kwankhede@nvidia.com>; kvm@vger.kernel.org; linux-
    > kernel@vger.kernel.org; cjia <cjia@nvidia.com>; netdev@vger.kernel.org
    > Subject: Re: [PATCH v2 0/2] Simplify mtty driver and mdev core
    >
    > On Tue, 20 Aug 2019 11:19:04 -0600
    > Alex Williamson <alex.williamson@redhat.com> wrote:
    >
    > > What about an alias based on the uuid? For example, we use 160-bit
    > > sha1s daily with git (uuids are only 128-bit), but we generally don't
    > > reference git commits with the full 20 character string. Generally 12
    > > characters is recommended to avoid ambiguity. Could mdev
    > > automatically create an abbreviated sha1 alias for the device? If so,
    > > how many characters should we use and what do we do on collision? The
    > > colliding device could add enough alias characters to disambiguate (we
    > > likely couldn't re-alias the existing device to disambiguate, but I'm
    > > not sure it matters, userspace has sysfs to associate aliases). Ex.
    > >
    > > UUID=$(uuidgen)
    > > ALIAS=$(echo $UUID | sha1sum | colrm 13)
    > >
    > > Since there seems to be some prefix overhead, as I ask about above in
    > > how many characters we actually have to work with in IFNAMESZ, maybe
    > > we start with 8 characters (matching your "index" namespace) and
    > > expand as necessary for disambiguation. If we can eliminate overhead
    > > in IFNAMESZ, let's start with 12. Thanks,
    > >
    > > Alex
    >
    > I really like that idea, and it seems the best option proposed yet, as we don't
    > need to create a secondary identifier.
    User setting this alias at mdev creation time and exposed via sysfs as read only attribute works.
    Exposing that as
    const char *mdev_alias(struct mdev_device *dev) to vendor drivers..

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