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Message-ID: <CANiDSCuuaJ9AOr9nGc+GN5UhHs2b0CCZvEnF1Qdw2vn9yo_uXw@mail.gmail.com>
Date: Fri, 23 May 2025 12:58:31 +0200
From: Ricardo Ribalda <ribalda@...omium.org>
To: Laurent Pinchart <laurent.pinchart@...asonboard.com>
Cc: Hans de Goede <hdegoede@...hat.com>, Mauro Carvalho Chehab <mchehab@...nel.org>, linux-media@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/4] media: uvcvideo: Refactor uvc_ctrl_set_handle()
Hi Laurent
On Fri, 23 May 2025 at 10:53, Laurent Pinchart
<laurent.pinchart@...asonboard.com> wrote:
>
> Hi Ricardo,
>
> On Fri, May 09, 2025 at 06:24:13PM +0000, Ricardo Ribalda wrote:
> > Today uvc_ctrl_set_handle() covers two use-uses: setting the handle and
> > clearing the handle. The only common code between the two cases is the
> > lockdep_assert_held.
> >
> > The code looks cleaner if we split these two usecases in two functions.
>
> It does indeed. Thanks for pushing for this :-)
>
> > We also take this opportunity to use pending_async_ctrls from ctrl where
> > possible.
> >
> > Signed-off-by: Ricardo Ribalda <ribalda@...omium.org>
> > ---
> > drivers/media/usb/uvc/uvc_ctrl.c | 65 +++++++++++++++++++++-------------------
> > 1 file changed, 35 insertions(+), 30 deletions(-)
> >
> > diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> > index 44b6513c526421943bb9841fb53dc5f8e9f93f02..26be1d0a1891cf3a9a7489f60f9a2931c78d3239 100644
> > --- a/drivers/media/usb/uvc/uvc_ctrl.c
> > +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> > @@ -1812,48 +1812,53 @@ static void uvc_ctrl_send_slave_event(struct uvc_video_chain *chain,
> > uvc_ctrl_send_event(chain, handle, ctrl, mapping, val, changes);
> > }
> >
> > -static int uvc_ctrl_set_handle(struct uvc_fh *handle, struct uvc_control *ctrl,
> > - struct uvc_fh *new_handle)
> > +static int uvc_ctrl_set_handle(struct uvc_fh *handle, struct uvc_control *ctrl)
> > {
> > - lockdep_assert_held(&handle->chain->ctrl_mutex);
> > -
> > - if (new_handle) {
> > - int ret;
> > + int ret;
> >
> > - if (ctrl->handle)
> > - dev_warn_ratelimited(&handle->stream->dev->udev->dev,
> > - "UVC non compliance: Setting an async control with a pending operation.");
> > + lockdep_assert_held(&handle->chain->ctrl_mutex);
> >
> > - if (new_handle == ctrl->handle)
> > - return 0;
> > + if (ctrl->handle) {
> > + dev_warn_ratelimited(&handle->stream->dev->udev->dev,
> > + "UVC non compliance: Setting an async control with a pending operation.");
> >
> > - if (ctrl->handle) {
> > - WARN_ON(!ctrl->handle->pending_async_ctrls);
> > - if (ctrl->handle->pending_async_ctrls)
> > - ctrl->handle->pending_async_ctrls--;
> > - ctrl->handle = new_handle;
> > - handle->pending_async_ctrls++;
> > + if (ctrl->handle == handle)
> > return 0;
> > - }
> > -
> > - ret = uvc_pm_get(handle->chain->dev);
> > - if (ret)
> > - return ret;
> >
> > - ctrl->handle = new_handle;
> > - handle->pending_async_ctrls++;
> > + WARN_ON(!ctrl->handle->pending_async_ctrls);
> > + if (ctrl->handle->pending_async_ctrls)
> > + ctrl->handle->pending_async_ctrls--;
> > + ctrl->handle = handle;
> > + ctrl->handle->pending_async_ctrls++;
> > return 0;
> > }
> >
> > + ret = uvc_pm_get(handle->chain->dev);
> > + if (ret)
> > + return ret;
> > +
> > + ctrl->handle = handle;
> > + ctrl->handle->pending_async_ctrls++;
> > + return 0;
> > +}
> > +
> > +static int uvc_ctrl_clear_handle(struct uvc_fh *handle,
> > + struct uvc_control *ctrl)
> > +{
> > + lockdep_assert_held(&handle->chain->ctrl_mutex);
> > +
> > /* Cannot clear the handle for a control not owned by us.*/
>
> While at it, I'll add a space before */ when applying.
>
> > if (WARN_ON(ctrl->handle != handle))
> > return -EINVAL;
>
> But actually, as the caller guarantees that handle == ctrl->handle in
> both call sites (renaming the function makes this clear), can we drop
> the handle argument to this function ?
>
> If that's fine with you, I'd like to also change the
> uvc_ctrl_set_handle() function to pass the ctrl argument first.
SGTM, let me know if you have time to do this or if you prefer that I do it.
Cheers
>
> >
> > - ctrl->handle = NULL;
> > - if (WARN_ON(!handle->pending_async_ctrls))
> > + if (WARN_ON(!ctrl->handle->pending_async_ctrls)) {
> > + ctrl->handle = NULL;
> > return -EINVAL;
> > - handle->pending_async_ctrls--;
> > + }
> > +
> > + ctrl->handle->pending_async_ctrls--;
> > uvc_pm_put(handle->chain->dev);
>
> This will need to become
>
> uvc_pm_put(ctrl->handle->chain->dev);
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
>
> > + ctrl->handle = NULL;
> > return 0;
> > }
> >
> > @@ -1871,7 +1876,7 @@ void uvc_ctrl_status_event(struct uvc_video_chain *chain,
> >
> > handle = ctrl->handle;
> > if (handle)
> > - uvc_ctrl_set_handle(handle, ctrl, NULL);
> > + uvc_ctrl_clear_handle(handle, ctrl);
> >
> > list_for_each_entry(mapping, &ctrl->info.mappings, list) {
> > s32 value;
> > @@ -2161,7 +2166,7 @@ static int uvc_ctrl_commit_entity(struct uvc_device *dev,
> >
> > if (!rollback && handle && !ret &&
> > ctrl->info.flags & UVC_CTRL_FLAG_ASYNCHRONOUS)
> > - ret = uvc_ctrl_set_handle(handle, ctrl, handle);
> > + ret = uvc_ctrl_set_handle(handle, ctrl);
> >
> > if (ret < 0 && !rollback) {
> > if (err_ctrl)
> > @@ -3271,7 +3276,7 @@ void uvc_ctrl_cleanup_fh(struct uvc_fh *handle)
> > for (unsigned int i = 0; i < entity->ncontrols; ++i) {
> > if (entity->controls[i].handle != handle)
> > continue;
> > - uvc_ctrl_set_handle(handle, &entity->controls[i], NULL);
> > + uvc_ctrl_clear_handle(handle, &entity->controls[i]);
> > }
> > }
> >
>
> --
> Regards,
>
> Laurent Pinchart
--
Ricardo Ribalda
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