On Mon, Aug 22, 2016 at 02:17:28PM +0200, Hans Verkuil wrote: > On 08/19/2016 12:23 PM, Sakari Ailus wrote: > > The struct cdev embedded in struct media_devnode contains its own kobj. > > Instead of trying to manage its lifetime separately from struct > > media_devnode, make the cdev kobj a parent of the struct media_device.dev > > kobj. > > > > The cdev will thus be released during unregistering the media_devnode, not > > in media_devnode.dev kobj's release callback. > > > > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> > > --- > > drivers/media/media-devnode.c | 5 ++--- > > 1 file changed, 2 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/media/media-devnode.c b/drivers/media/media-devnode.c > > index aa8030b..69f84a7 100644 > > --- a/drivers/media/media-devnode.c > > +++ b/drivers/media/media-devnode.c > > @@ -63,9 +63,6 @@ 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); > > > > @@ -246,6 +243,7 @@ int __must_check media_devnode_register(struct media_devnode *devnode, > > > > /* Part 2: Initialize and register the character device */ > > cdev_init(&devnode->cdev, &media_devnode_fops); > > + devnode->cdev.kobj.parent = &devnode->dev.kobj; > > devnode->cdev.owner = owner; > > > > ret = cdev_add(&devnode->cdev, MKDEV(MAJOR(media_dev_t), devnode->minor), 1); > > @@ -291,6 +289,7 @@ void media_devnode_unregister(struct media_devnode *devnode) > > clear_bit(MEDIA_FLAG_REGISTERED, &devnode->flags); > > mutex_unlock(&media_devnode_lock); > > device_unregister(&devnode->dev); > > + cdev_del(&devnode->cdev); > > Are you sure about this order? Shouldn't cdev_del be called first? > > The register() calls cdev_add() before device_add(), so I would expect the > reverse order here. This is also what cec-core.c does. Correct. It's possible that device_unregister() releases the last reference to the struct device, which in turn causes the memory to be released. I'll fix that. -- Sakari Ailus e-mail: sakari.ailus@xxxxxx XMPP: sailus@xxxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
