Hi Laurent, On Wed, Feb 07, 2024 at 12:08:10PM +0200, Laurent Pinchart wrote: > Hi Sakari, > > Thank you for the patch. > > On Wed, Dec 20, 2023 at 12:36:54PM +0200, Sakari Ailus wrote: > > The parent of the character device related to the media devnode is the > > media devnode. Thus the character device needs to be released before the > > media devnode's release function. Move it to unregistering of the media > > devnode, which mirrors adding the character device in conjunction with > > registering the media devnode. > > > > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> > > Acked-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx> > > --- > > drivers/media/mc/mc-devnode.c | 4 +--- > > 1 file changed, 1 insertion(+), 3 deletions(-) > > > > diff --git a/drivers/media/mc/mc-devnode.c b/drivers/media/mc/mc-devnode.c > > index 7e22938dfd81..8bc7450ac144 100644 > > --- a/drivers/media/mc/mc-devnode.c > > +++ b/drivers/media/mc/mc-devnode.c > > @@ -51,9 +51,6 @@ static void media_devnode_release(struct device *cd) > > > > mutex_lock(&media_devnode_lock); > > > > - /* Delete the cdev on this minor as well */ > > - cdev_del(&devnode->cdev); > > - > > /* Mark device node number as free */ > > clear_bit(devnode->minor, media_devnode_nums); > > Should this be moved to media_devnode_unregister() too ? It can be done > in a separate patch. Good question. Yes, I think that seems reasonable. The minor isn't needed after unregistering the device. > > > > > @@ -270,6 +267,7 @@ void media_devnode_unregister(struct media_devnode *devnode) > > clear_bit(MEDIA_FLAG_REGISTERED, &devnode->flags); > > mutex_unlock(&media_devnode_lock); > > > > + cdev_del(&devnode->cdev); > > I initially wondered if this could raise with the cdev access in > media_open(), as the media_devnode_lock is released just before calling > cdev_dev(), but my understanding is that the dev/open race is properly > handled in the cdev layer. > > Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> Thanks! > > I wonder if a similar change in v4l2-dev.c would be beneficial. Quite possibly. Let's see... -- Kind regards, Sakari Ailus
