[PATCH 1/9] drm/connector: Make the drm_sysfs connector->kdev device hold a reference to the connector

[Greg Kroah-Hartman]

On Thu, Apr 29, 2021 at 01:40:28PM +0200, Daniel Vetter wrote:
> On Wed, Apr 28, 2021 at 11:52:49PM +0200, Hans de Goede wrote:
> > Userspace could hold open a reference to the connector->kdev device,
> > through e.g. holding a sysfs-atrtribute open after
> > drm_sysfs_connector_remove() has been called. In this case the connector
> > could be free-ed while the connector->kdev device's drvdata is still
> > pointing to it.
> > 
> > Give drm_connector devices there own device type, which allows
> > us to specify our own release function and make drm_sysfs_connector_add()
> > take a reference on the connector object, and have the new release
> > function put the reference when the device is released.
> > 
> > Giving drm_connector devices there own device type, will also allow
> > checking if a device is a drm_connector device with a
> > "if (device->type == &drm_sysfs_device_connector)" check.
> > 
> > Note that the setting of the name member of the device_type struct will
> > cause udev events for drm_connector-s to now contain DEVTYPE=drm_connector
> > as extra info. So this extends the uevent part of the userspace API.
> > 
> > Signed-off-by: Hans de Goede <hdegoede at redhat.com>
> 
> Are you sure? I thought sysfs is supposed to flush out any pending
> operations (they complete fast) and handle open fd internally?

Yes, it "should" :)