Re: [PATCH] mdev: Send uevents around parent device registration

Kirti Wankhede
2019-06-26T19:04:14Z

On 6/26/2019 11:35 PM, Alex Williamson wrote:
> On Wed, 26 Jun 2019 23:23:00 +0530
> Kirti Wankhede <kwankhede@nvidia.com> wrote:
>
>> On 6/26/2019 7:57 PM, Alex Williamson wrote:
>>> This allows udev to trigger rules when a parent device is registered
>>> or unregistered from mdev.
>>>
>>> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
>>> ---
>>> drivers/vfio/mdev/mdev_core.c | 10 ++++++++--
>>> 1 file changed, 8 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
>>> index ae23151442cb..ecec2a3b13cb 100644
>>> --- a/drivers/vfio/mdev/mdev_core.c
>>> +++ b/drivers/vfio/mdev/mdev_core.c
>>> @@ -146,6 +146,8 @@ int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
>>> {
>>> int ret;
>>> struct mdev_parent *parent;
>>> + char *env_string = "MDEV_STATE=registered";
>>> + char *envp[] = { env_string, NULL };
>>>
>>> /* check for mandatory ops */
>>> if (!ops || !ops->create || !ops->remove || !ops->supported_type_groups)
>>> @@ -196,7 +198,8 @@ int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
>>> list_add(&parent->next, &parent_list);
>>> mutex_unlock(&parent_list_lock);
>>>
>>> - dev_info(dev, "MDEV: Registered\n");
>>> + kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);
>>> +
>>
>> Its good to have udev event, but don't remove debug print from dmesg.
>> Same for unregister.
>
> Who consumes these? They seem noisy. Thanks,
>

I don't think its noisy, its more of logging purpose. This is seen in
kernel log only when physical device is registered to mdev.

Thanks,
Kirti

> Alex
>
>>> return 0;
>>>
>>> add_dev_err:
>>> @@ -220,6 +223,8 @@ EXPORT_SYMBOL(mdev_register_device);
>>> void mdev_unregister_device(struct device *dev)
>>> {
>>> struct mdev_parent *parent;
>>> + char *env_string = "MDEV_STATE=unregistered";
>>> + char *envp[] = { env_string, NULL };
>>>
>>> mutex_lock(&parent_list_lock);
>>> parent = __find_parent_device(dev);
>>> @@ -228,7 +233,6 @@ void mdev_unregister_device(struct device *dev)
>>> mutex_unlock(&parent_list_lock);
>>> return;
>>> }
>>> - dev_info(dev, "MDEV: Unregistering\n");
>>>
>>> list_del(&parent->next);
>>> mutex_unlock(&parent_list_lock);
>>> @@ -243,6 +247,8 @@ void mdev_unregister_device(struct device *dev)
>>> up_write(&parent->unreg_sem);
>>>
>>> mdev_put_parent(parent);
>>> +
>>> + kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);
>>> }
>>> EXPORT_SYMBOL(mdev_unregister_device);
>>>
>>>
>