Hi Sergey
On Wed, 22 Nov 2023 at 08:21, Sergey Senozhatsky
<senozhatsky@xxxxxxxxxxxx> wrote:
>
> On (23/11/21 19:53), Ricardo Ribalda wrote:
> > uvc_status_stop() handles properly the race conditions with the
> > asynchronous worker.
> > Let's use uvc_status_stop() for all the code paths that require stopping
> > it.
> >
> > Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
> > ---
> > drivers/media/usb/uvc/uvc_ctrl.c | 4 ----
> > drivers/media/usb/uvc/uvc_status.c | 2 +-
> > 2 files changed, 1 insertion(+), 5 deletions(-)
> >
> > diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> > index e59a463c2761..8e22a07e3e7b 100644
> > --- a/drivers/media/usb/uvc/uvc_ctrl.c
> > +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> > @@ -2765,10 +2765,6 @@ void uvc_ctrl_cleanup_device(struct uvc_device *dev)
> > struct uvc_entity *entity;
> > unsigned int i;
> >
> > - /* Can be uninitialized if we are aborting on probe error. */
> > - if (dev->async_ctrl.work.func)
> > - cancel_work_sync(&dev->async_ctrl.work);
> > -
> > /* Free controls and control mappings for all entities. */
> > list_for_each_entry(entity, &dev->entities, list) {
> > for (i = 0; i < entity->ncontrols; ++i) {
> > diff --git a/drivers/media/usb/uvc/uvc_status.c b/drivers/media/usb/uvc/uvc_status.c
> > index a78a88c710e2..0208612a9f12 100644
> > --- a/drivers/media/usb/uvc/uvc_status.c
> > +++ b/drivers/media/usb/uvc/uvc_status.c
> > @@ -292,7 +292,7 @@ int uvc_status_init(struct uvc_device *dev)
> >
> > void uvc_status_unregister(struct uvc_device *dev)
> > {
> > - usb_kill_urb(dev->int_urb);
> > + uvc_status_stop(dev);
>
> Sort of feels like this needs dev->lock somewhere here. Should we move 3/3
> to the head of the series?
>
> The question is, can this be called in parallel with uvc_v4l2_release(),
> for instance?
I can be called in parallel with uvc_v4l2_release(), but
uvc_status_stop() is thread-safe and does not take any locks after:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=619d9b710cf06f7a00a17120ca92333684ac45a8
So this "should" be good. key-word here is should :P
>
> > uvc_input_unregister(dev);
> > }
--
Ricardo Ribalda
