RE: [PATCH 2/4] mdev: Make mdev alias unique among all mdevs

Parav Pandit
2019-08-27T04:29:26Z

Hi Mark,

> -----Original Message-----
> From: Mark Bloch <markb@mellanox.com>
> Sent: Tuesday, August 27, 2019 4:32 AM
> To: Parav Pandit <parav@mellanox.com>; alex.williamson@redhat.com; Jiri
> Pirko <jiri@mellanox.com>; kwankhede@nvidia.com; cohuck@redhat.com;
> davem@davemloft.net
> Cc: kvm@vger.kernel.org; linux-kernel@vger.kernel.org;
> netdev@vger.kernel.org
> Subject: Re: [PATCH 2/4] mdev: Make mdev alias unique among all mdevs
>
>
>
> On 8/26/19 1:41 PM, Parav Pandit wrote:
> > Mdev alias should be unique among all the mdevs, so that when such
> > alias is used by the mdev users to derive other objects, there is no
> > collision in a given system.
> >
> > Signed-off-by: Parav Pandit <parav@mellanox.com>
> > ---
> > drivers/vfio/mdev/mdev_core.c | 5 +++++
> > 1 file changed, 5 insertions(+)
> >
> > diff --git a/drivers/vfio/mdev/mdev_core.c
> > b/drivers/vfio/mdev/mdev_core.c index e825ff38b037..6eb37f0c6369
> > 100644
> > --- a/drivers/vfio/mdev/mdev_core.c
> > +++ b/drivers/vfio/mdev/mdev_core.c
> > @@ -375,6 +375,11 @@ int mdev_device_create(struct kobject *kobj,
> struct device *dev,
> > ret = -EEXIST;
> > goto mdev_fail;
> > }
> > + if (tmp->alias && strcmp(tmp->alias, alias) == 0) {
>
> alias can be NULL here no?
>
If alias is NULL, tmp->alias would also be null because for given parent either we have alias or we don’t.
So its not possible to have tmp->alias as null and alias as non null.
But it may be good/defensive to add check for both.

> > + mutex_unlock(&mdev_list_lock);
> > + ret = -EEXIST;
> > + goto mdev_fail;
> > + }
> > }
> >
> > mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
> >
>
> Mark