Hi Sergey
On Wed, 22 Nov 2023 at 08:35, Ricardo Ribalda <ribalda@xxxxxxxxxxxx> wrote:
>
> 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
To be on the safe side I am not going to run the async work on the
release path. will send a new revision
>
>
> >
> > > uvc_input_unregister(dev);
> > > }
>
>
>
> --
> Ricardo Ribalda
--
Ricardo Ribalda
