diff mbox series

[v1,2/5] mdev: Make mdev alias unique among all mdevs

Message ID 20190827191654.41161-3-parav@mellanox.com (mailing list archive)
State New, archived
Headers show
Series Introduce variable length mdev alias | expand

Commit Message

Parav Pandit Aug. 27, 2019, 7:16 p.m. UTC
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>

---
Changelog:
v0->v1:
 - Fixed inclusiong of alias for NULL check
 - Added ratelimited debug print for sha1 hash collision error
---
 drivers/vfio/mdev/mdev_core.c | 7 +++++++
 1 file changed, 7 insertions(+)

Comments

Alex Williamson Aug. 28, 2019, 9:36 p.m. UTC | #1
On Tue, 27 Aug 2019 14:16:51 -0500
Parav Pandit <parav@mellanox.com> 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>
> 
> ---
> Changelog:
> v0->v1:
>  - Fixed inclusiong of alias for NULL check
>  - Added ratelimited debug print for sha1 hash collision error
> ---
>  drivers/vfio/mdev/mdev_core.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
> index 62d29f57fe0c..4b9899e40665 100644
> --- a/drivers/vfio/mdev/mdev_core.c
> +++ b/drivers/vfio/mdev/mdev_core.c
> @@ -375,6 +375,13 @@ int mdev_device_create(struct kobject *kobj, struct device *dev,
>  			ret = -EEXIST;
>  			goto mdev_fail;
>  		}
> +		if (tmp->alias && alias && strcmp(tmp->alias, alias) == 0) {

Nit, test if the device we adding has an alias before the device we're
testing against.  The compiler can better optimize keeping alias hot.
Thanks,

Alex

> +			mutex_unlock(&mdev_list_lock);
> +			ret = -EEXIST;
> +			dev_dbg_ratelimited(dev, "Hash collision in alias creation for UUID %pUl\n",
> +					    uuid);
> +			goto mdev_fail;
> +		}
>  	}
>  
>  	mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
Parav Pandit Aug. 29, 2019, 9:07 a.m. UTC | #2
> -----Original Message-----
> From: Alex Williamson <alex.williamson@redhat.com>
> Sent: Thursday, August 29, 2019 3:07 AM
> To: Parav Pandit <parav@mellanox.com>
> Cc: Jiri Pirko <jiri@mellanox.com>; kwankhede@nvidia.com;
> cohuck@redhat.com; davem@davemloft.net; kvm@vger.kernel.org; linux-
> kernel@vger.kernel.org; netdev@vger.kernel.org
> Subject: Re: [PATCH v1 2/5] mdev: Make mdev alias unique among all mdevs
> 
> On Tue, 27 Aug 2019 14:16:51 -0500
> Parav Pandit <parav@mellanox.com> 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>
> >
> > ---
> > Changelog:
> > v0->v1:
> >  - Fixed inclusiong of alias for NULL check
> >  - Added ratelimited debug print for sha1 hash collision error
> > ---
> >  drivers/vfio/mdev/mdev_core.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> >
> > diff --git a/drivers/vfio/mdev/mdev_core.c
> > b/drivers/vfio/mdev/mdev_core.c index 62d29f57fe0c..4b9899e40665
> > 100644
> > --- a/drivers/vfio/mdev/mdev_core.c
> > +++ b/drivers/vfio/mdev/mdev_core.c
> > @@ -375,6 +375,13 @@ int mdev_device_create(struct kobject *kobj, struct
> device *dev,
> >  			ret = -EEXIST;
> >  			goto mdev_fail;
> >  		}
> > +		if (tmp->alias && alias && strcmp(tmp->alias, alias) == 0) {
> 
> Nit, test if the device we adding has an alias before the device we're testing
> against.  The compiler can better optimize keeping alias hot.
> Thanks,
> 
Ok. will do.

> Alex
diff mbox series

Patch

diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index 62d29f57fe0c..4b9899e40665 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -375,6 +375,13 @@  int mdev_device_create(struct kobject *kobj, struct device *dev,
 			ret = -EEXIST;
 			goto mdev_fail;
 		}
+		if (tmp->alias && alias && strcmp(tmp->alias, alias) == 0) {
+			mutex_unlock(&mdev_list_lock);
+			ret = -EEXIST;
+			dev_dbg_ratelimited(dev, "Hash collision in alias creation for UUID %pUl\n",
+					    uuid);
+			goto mdev_fail;
+		}
 	}
 
 	mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);