[Mesa-dev] [PATCH] gbm: Use unsigned for BO offset getter

[Jason Ekstrand]

Reviewed-by: Jason Ekstrand <jason at jlekstrand.net>

Please land soon so the old API can exist for as short a time as possible.
:-)

On Thu, Mar 23, 2017 at 8:14 AM, Daniel Stone <daniels at collabora.com> wrote:

> The actual offset returned is uint32_t, however int64_t was used as the
> return type from gbm_bo_get_offset to allow negative returns to signal
> errors to the caller.
>
> In case of an error getting the offset, the user will also be unable to
> get the handle/FD, and thus have nothing to offset into. This means that
> returning 0 as an error value is harmless, allowing us to change the
> return type to uint32_t in order to avoid signed/unsigned confusion in
> callers.
>
> Signed-off-by: Daniel Stone <daniels at collabora.com>
> Cc: Ben Widawsky <ben at bwidawsk.net>
> Cc: Jason Ekstrand <jason at jlekstrand.net>
> ---
>  src/gbm/backends/dri/gbm_dri.c | 18 +++++++++---------
>  src/gbm/main/gbm.c             |  2 +-
>  src/gbm/main/gbm.h             |  2 +-
>  src/gbm/main/gbmint.h          |  2 +-
>  4 files changed, 12 insertions(+), 12 deletions(-)
>
> diff --git a/src/gbm/backends/dri/gbm_dri.c b/src/gbm/backends/dri/gbm_
> dri.c
> index 84b4dd8853..f8c005c15b 100644
> --- a/src/gbm/backends/dri/gbm_dri.c
> +++ b/src/gbm/backends/dri/gbm_dri.c
> @@ -710,22 +710,22 @@ gbm_dri_bo_get_stride(struct gbm_bo *_bo, int plane)
>     return (uint32_t)stride;
>  }
>
> -static int64_t
> +static uint32_t
>  gbm_dri_bo_get_offset(struct gbm_bo *_bo, int plane)
>  {
>     struct gbm_dri_device *dri = gbm_dri_device(_bo->gbm);
>     struct gbm_dri_bo *bo = gbm_dri_bo(_bo);
>     int offset = 0;
>
> -   if (!dri->image || dri->image->base.version < 13 ||
> !dri->image->fromPlanar) {
> -      errno = ENOSYS;
> -      return -1;
> -   }
> +   /* These error cases do not actually return an error code, as the user
> +    * will also fail to obtain the handle/FD from the BO. In that case,
> the
> +    * offset is irrelevant, as they have no buffer to offset into, so
> +    * returning 0 is harmless. */
> +   if (!dri->image || dri->image->base.version < 13 ||
> !dri->image->fromPlanar)
> +      return 0;
>
> -   if (plane >= get_number_planes(dri, bo->image)) {
> -      errno = EINVAL;
> -      return -2;
> -   }
> +   if (plane >= get_number_planes(dri, bo->image))
> +      return 0;
>
>      /* Dumb images have no offset */
>     if (bo->image == NULL) {
> diff --git a/src/gbm/main/gbm.c b/src/gbm/main/gbm.c
> index 19dc5db901..79d78b763e 100644
> --- a/src/gbm/main/gbm.c
> +++ b/src/gbm/main/gbm.c
> @@ -203,7 +203,7 @@ gbm_bo_get_format(struct gbm_bo *bo)
>   * \param bo The buffer object
>   * \return The offset
>   */
> -GBM_EXPORT int64_t
> +GBM_EXPORT uint32_t
>  gbm_bo_get_offset(struct gbm_bo *bo, int plane)
>  {
>     return bo->gbm->bo_get_offset(bo, plane);
> diff --git a/src/gbm/main/gbm.h b/src/gbm/main/gbm.h
> index a774b50951..b52137ed01 100644
> --- a/src/gbm/main/gbm.h
> +++ b/src/gbm/main/gbm.h
> @@ -315,7 +315,7 @@ gbm_bo_get_stride_for_plane(struct gbm_bo *bo, int
> plane);
>  uint32_t
>  gbm_bo_get_format(struct gbm_bo *bo);
>
> -int64_t
> +uint32_t
>  gbm_bo_get_offset(struct gbm_bo *bo, int plane);
>
>  struct gbm_device *
> diff --git a/src/gbm/main/gbmint.h b/src/gbm/main/gbmint.h
> index 5ad85cc80f..c27a7a560a 100644
> --- a/src/gbm/main/gbmint.h
> +++ b/src/gbm/main/gbmint.h
> @@ -81,7 +81,7 @@ struct gbm_device {
>     int (*bo_get_planes)(struct gbm_bo *bo);
>     union gbm_bo_handle (*bo_get_handle)(struct gbm_bo *bo, int plane);
>     uint32_t (*bo_get_stride)(struct gbm_bo *bo, int plane);
> -   int64_t (*bo_get_offset)(struct gbm_bo *bo, int plane);
> +   uint32_t (*bo_get_offset)(struct gbm_bo *bo, int plane);
>     uint64_t (*bo_get_modifier)(struct gbm_bo *bo);
>     void (*bo_destroy)(struct gbm_bo *bo);
>
> --
> 2.12.1
>
>
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