[FFmpeg-devel] [PATCH] hwcontext_opencl: Use correct function to enumerate devices

[Song, Ruiling]

> -----Original Message-----
> From: ffmpeg-devel [mailto:ffmpeg-devel-bounces at ffmpeg.org] On Behalf Of
> Mark Thompson
> Sent: Wednesday, November 28, 2018 8:17 AM
> To: ffmpeg-devel at ffmpeg.org
> Subject: [FFmpeg-devel] [PATCH] hwcontext_opencl: Use correct function to
> enumerate devices
> 
> Also assert that all required functions are present.
> ---
> On 26/11/2018 08:57, Song, Ruiling wrote:
> >> -----Original Message-----
> >> From: ffmpeg-devel [mailto:ffmpeg-devel-bounces at ffmpeg.org] On Behalf
> Of
> >> Mark Thompson
> >> Sent: Monday, November 26, 2018 6:08 AM
> >> To: FFmpeg development discussions and patches <ffmpeg-
> devel at ffmpeg.org>
> >> Subject: [FFmpeg-devel] [PATCH] hwcontext_opencl: Use correct function to
> >> enumerate devices
> >>
> >> ---
> >>  libavutil/hwcontext_opencl.c | 6 +++---
> >>  1 file changed, 3 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/libavutil/hwcontext_opencl.c b/libavutil/hwcontext_opencl.c
> >> index e6cef74269..6a26354c87 100644
> >> --- a/libavutil/hwcontext_opencl.c
> >> +++ b/libavutil/hwcontext_opencl.c
> >> @@ -542,9 +542,9 @@ static int
> >> opencl_device_create_internal(AVHWDeviceContext *hwdev,
> >>                  continue;
> >>          }
> >>
> >> -        err = opencl_enumerate_devices(hwdev, platforms[p], platform_name,
> >> -                                       &nb_devices, &devices,
> >> -                                       selector->context);
> >> +        err = selector->enumerate_devices(hwdev, platforms[p],
> platform_name,
> >> +                                          &nb_devices, &devices,
> >> +                                          selector->context);
> > I think it is better to check enumerate_devices  against null pointer before
> calling it, although it should works well currently.
> 
> The two enumerate functions should always be set when entering the function,
> since they are always required.  (Unlike the filter, where "do nothing" is a
> reasonable case.)
> 
> How about an assert at the start of the function to check that, like this?
Yes, that's good. It is just helpful when somebody add new platform support but happened to forget to give a meaningful function pointer.

Ruiling
> 
> - Mark
> 
> 
>  libavutil/hwcontext_opencl.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/libavutil/hwcontext_opencl.c b/libavutil/hwcontext_opencl.c
> index be71c8323e..d3df6221c4 100644
> --- a/libavutil/hwcontext_opencl.c
> +++ b/libavutil/hwcontext_opencl.c
> @@ -500,6 +500,9 @@ static int
> opencl_device_create_internal(AVHWDeviceContext *hwdev,
>           *device_name_src   = NULL;
>      int err, found, p, d;
> 
> +    av_assert0(selector->enumerate_platforms &&
> +               selector->enumerate_devices);
> +
>      err = selector->enumerate_platforms(hwdev, &nb_platforms, &platforms,
>                                          selector->context);
>      if (err)
> @@ -531,9 +534,9 @@ static int
> opencl_device_create_internal(AVHWDeviceContext *hwdev,
>                  continue;
>          }
> 
> -        err = opencl_enumerate_devices(hwdev, platforms[p], platform_name,
> -                                       &nb_devices, &devices,
> -                                       selector->context);
> +        err = selector->enumerate_devices(hwdev, platforms[p], platform_name,
> +                                          &nb_devices, &devices,
> +                                          selector->context);
>          if (err < 0)
>              continue;
> 
> --
> 2.19.1
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