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From:   Parav Pandit <parav@mellanox.com>
To:     Cornelia Huck <cohuck@redhat.com>
CC:     "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
        "wankhede@nvidia.com" <wankhede@nvidia.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "alex.williamson@redhat.com" <alex.williamson@redhat.com>,
        "cjia@nvidia.com" <cjia@nvidia.com>
Subject: RE: [PATCH v1 2/2] vfio/mdev: Removed unused and redundant API for
 mdev UUID
Thread-Topic: [PATCH v1 2/2] vfio/mdev: Removed unused and redundant API for
 mdev UUID
Thread-Index: AQHVTGHewj+1neBmdkuk/1V2f0BrWKbvbAyAgAB0EUCAAQ3sgIAAWv7w
Date:   Thu, 8 Aug 2019 14:01:37 +0000
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References: <20190802065905.45239-1-parav@mellanox.com>
        <20190806141826.52712-1-parav@mellanox.com>
        <20190806141826.52712-3-parav@mellanox.com>
        <20190807112801.6b2ceb36.cohuck@redhat.com>
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 <20190808102931.40c6b4ae.cohuck@redhat.com>
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> -----Original Message-----
> From: Cornelia Huck <cohuck@redhat.com>
> Sent: Thursday, August 8, 2019 2:00 PM
> To: Parav Pandit <parav@mellanox.com>
> Cc: kvm@vger.kernel.org; wankhede@nvidia.com; linux-
> kernel@vger.kernel.org; alex.williamson@redhat.com; cjia@nvidia.com
> Subject: Re: [PATCH v1 2/2] vfio/mdev: Removed unused and redundant API
> for mdev UUID
>=20
> On Wed, 7 Aug 2019 16:33:11 +0000
> Parav Pandit <parav@mellanox.com> wrote:
>=20
> > > -----Original Message-----
> > > From: Cornelia Huck <cohuck@redhat.com>
> > > Sent: Wednesday, August 7, 2019 2:58 PM
> > > To: Parav Pandit <parav@mellanox.com>
> > > Cc: kvm@vger.kernel.org; wankhede@nvidia.com; linux-
> > > kernel@vger.kernel.org; alex.williamson@redhat.com; cjia@nvidia.com
> > > Subject: Re: [PATCH v1 2/2] vfio/mdev: Removed unused and redundant
> > > API for mdev UUID
> > >
> > > On Tue,  6 Aug 2019 09:18:26 -0500
> > > Parav Pandit <parav@mellanox.com> wrote:
> > >
> > > > There is no single production driver who is interested in mdev
> > > > device uuid. Currently UUID is mainly used to derive a device name.
> > > > Additionally mdev device name is already available using core
> > > > kernel API dev_name().
> > >
> > > Well, the mdev code actually uses the uuid to check for duplicates
> > > before registration with the driver core would fail... I'd just drop
> > > the two sentences
> > Yes, it does the check. But its mainly used to derive a device name.
> > And to ensure that there are no two devices with duplicate name, it
> compares with the uuid.
> >
> > Even this 16 bytes storage is redundant.
> > Subsequently, I will submit a patch to get rid of storing this 16 bytes=
 of
> UUID too.
> > Because for duplicate name check, device name itself is pretty good
> enough.
> >
> > Since I ran out of time and rc-4 is going on, I differed the 3rd simpli=
fication
> patch.
>=20
> I'm not sure why we'd want to ditch the uuid; it's not like it is taking =
up huge
> amounts of space... and I see the device name being derived from the
> unique identifier that is the uuid, and not as the unique identifier itse=
lf.
>
Its just extra storage where ID is already present in device name.
Its redundant. Same functionality can be achieved without its storage, so i=
t's better to simplify.
Anyways, will handle it right after this two patches.

I realized that I had typo in the email of Kirti. So resending it with corr=
ected email.

> >
> > Commit message actually came from the thoughts of 3rd patch, but I see
> that without it, its not so intuitive.
> >
> > > talking about the device name, IMHO they don't really add useful
> > > information; but I'll leave that decision to the maintainers.
> > >
> > > >
> > > > Hence removed unused exported symbol.
> > > >
> > > > Signed-off-by: Parav Pandit <parav@mellanox.com>
> > > > ---
> > > > Changelog:
> > > > v0->v1:
> > > >  - Updated commit log to address comments from Cornelia
> > > > ---
> > > >  drivers/vfio/mdev/mdev_core.c | 6 ------
> > > >  include/linux/mdev.h          | 1 -
> > > >  2 files changed, 7 deletions(-)
> > >
> > > Reviewed-by: Cornelia Huck <cohuck@redhat.com>
> > Thanks for the review.