linux-kernel - RE: [PATCH v1 2/2] vfio/mdev: Removed unused and redundant API for mdev UUID

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Date:   Wed, 7 Aug 2019 16:33:11 +0000
From:   Parav Pandit <parav@...lanox.com>
To:     Cornelia Huck <cohuck@...hat.com>
CC:     "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "wankhede@...dia.com" <wankhede@...dia.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "alex.williamson@...hat.com" <alex.williamson@...hat.com>,
        "cjia@...dia.com" <cjia@...dia.com>
Subject: RE: [PATCH v1 2/2] vfio/mdev: Removed unused and redundant API for
 mdev UUID



> -----Original Message-----
> From: Cornelia Huck <cohuck@...hat.com>
> Sent: Wednesday, August 7, 2019 2:58 PM
> To: Parav Pandit <parav@...lanox.com>
> Cc: kvm@...r.kernel.org; wankhede@...dia.com; linux-
> kernel@...r.kernel.org; alex.williamson@...hat.com; cjia@...dia.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@...lanox.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 simplification patch.

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@...lanox.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@...hat.com>
Thanks for the review.