Em Fri, 10 Aug 2018 09:32:53 +0200
Hans Verkuil <hverkuil@xxxxxxxxx> escreveu:
> On 08/09/2018 09:55 PM, Mauro Carvalho Chehab wrote:
> > Em Sat, 4 Aug 2018 14:44:57 +0200
> > Hans Verkuil <hverkuil@xxxxxxxxx> escreveu:
> >
> >> From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
> >>
> >> Add media_request_get_by_fd() to find a request based on the file
> >> descriptor.
> >>
> >> The caller has to call media_request_put() for the returned
> >> request since this function increments the refcount.
> >>
> >> Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
> >> Acked-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> >> ---
> >> drivers/media/media-request.c | 40 +++++++++++++++++++++++++++++++++++
> >> include/media/media-request.h | 24 +++++++++++++++++++++
> >> 2 files changed, 64 insertions(+)
> >>
> >> diff --git a/drivers/media/media-request.c b/drivers/media/media-request.c
> >> index 253068f51a1f..4b523f3a03a3 100644
> >> --- a/drivers/media/media-request.c
> >> +++ b/drivers/media/media-request.c
> >> @@ -231,6 +231,46 @@ static const struct file_operations request_fops = {
> >> .release = media_request_close,
> >> };
> >>
> >> +struct media_request *
> >> +media_request_get_by_fd(struct media_device *mdev, int request_fd)
> >> +{
> >> + struct file *filp;
> >> + struct media_request *req;
> >> +
> >> + if (!mdev || !mdev->ops ||
> >> + !mdev->ops->req_validate || !mdev->ops->req_queue)
> >> + return ERR_PTR(-EPERM);
> >
> > EPERM? I guess ENOTTY would be better.
> >
> > Any reason why using EPERM?
>
> This is called by e.g. VIDIOC_QBUF or VIDIOC_S/G/TRY_EXT_CTRLS where someone
> sets request_fd. Then this function is called to obtain the corresponding
> media_request struct. If requests are not supported, then EPERM is returned.
>
> Returning ENOTTY would be wrong, since VIDIOC_QBUF etc. are definitely implemented,
> instead they just do not permit the use of requests.
>
> Let me know if I can add your Reviewed-by after this explanation.
Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@xxxxxxxxxx>
>
> Regards,
>
> Hans
Thanks,
Mauro
