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.
Regards,
Hans
