Re: [PATCH] drm/sysfs: fix hotplug regression since lifetime changes

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, Nov 21, 2013 at 10:22:55AM +0100, Daniel Vetter wrote:
> On Thu, Nov 21, 2013 at 11:51:04AM +1000, Dave Airlie wrote:
> > 5bdebb183c9702a8c57a01dff09337be3de337a6 changed the lifetimes, but it
> > also meant we no longer set the device_type field properly, so the
> > hotplug events in userspace weren't fully formed enough for drivers to care.
> > 
> > Reported-by: Jesse Barnes <jbarnes@virtuosugeek.org>
> > Signed-off-by: Dave Airlie <airlied@redhat.com>
> > ---
> >  drivers/gpu/drm/drm_sysfs.c | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c
> > index 1a35ea5..c6a3902 100644
> > --- a/drivers/gpu/drm/drm_sysfs.c
> > +++ b/drivers/gpu/drm/drm_sysfs.c
> > @@ -516,6 +516,7 @@ int drm_sysfs_device_add(struct drm_minor *minor)
> >  		DRM_ERROR("device create failed %ld\n", PTR_ERR(minor->kdev));
> >  		return PTR_ERR(minor->kdev);
> >  	}
> > +	minor->kdev->type = &drm_sysfs_device_minor;
> 
> Isn't this one of the sysfs races Greg is fighting against? At least from
> a cursor read through the driver core it looks like we'd better set the
> dev->type before we set it up with device_create().
> 
> Cc'ing Greg for insight.

No, setting the type at this point is fine, I don't see the race, care
to explain what I'm missing?

But, if you want to be "correct" you can just create the device
structure yourself, set the fields (including the type) and then call
device_register() yourself.  Look at usb_create_ep_devs() for an
example of how to do this.

thanks,

greg k-h