On 2/16/23 23:44, Jani Nikula wrote:
> Avoid figuring out the header pointer multiple times.
>
> Cc: Iaroslav Boliukin <iam@xxxxxxx>
> Cc: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx>
> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
> ---
> drivers/gpu/drm/drm_displayid.c | 17 ++++++++---------
> 1 file changed, 8 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_displayid.c b/drivers/gpu/drm/drm_displayid.c
> index 7d03159dc146..0de9b5530393 100644
> --- a/drivers/gpu/drm/drm_displayid.c
> +++ b/drivers/gpu/drm/drm_displayid.c
> @@ -20,7 +20,8 @@ displayid_get_header(const u8 *displayid, int length, int index)
> return base;
> }
>
> -static int validate_displayid(const u8 *displayid, int length, int idx)
> +static const struct displayid_header *
> +validate_displayid(const u8 *displayid, int length, int idx)
> {
> int i, dispid_length;
> u8 csum = 0;
> @@ -28,7 +29,7 @@ static int validate_displayid(const u8 *displayid, int length, int idx)
>
> base = displayid_get_header(displayid, length, idx);
> if (IS_ERR(base))
> - return PTR_ERR(base);
> + return base;
>
> DRM_DEBUG_KMS("base revision 0x%x, length %d, %d %d\n",
> base->rev, base->bytes, base->prod_id, base->ext_count);
> @@ -36,16 +37,16 @@ static int validate_displayid(const u8 *displayid, int length, int idx)
> /* +1 for DispID checksum */
> dispid_length = sizeof(*base) + base->bytes + 1;
> if (dispid_length > length - idx)
> - return -EINVAL;
> + return ERR_PTR(-EINVAL);
>
> for (i = 0; i < dispid_length; i++)
> csum += displayid[idx + i];
> if (csum) {
> DRM_NOTE("DisplayID checksum invalid, remainder is %d\n", csum);
> - return -EINVAL;
> + return ERR_PTR(-EINVAL);
> }
>
> - return 0;
> + return base;
> }
>
> static const u8 *drm_find_displayid_extension(const struct drm_edid *drm_edid,
> @@ -54,7 +55,6 @@ static const u8 *drm_find_displayid_extension(const struct drm_edid *drm_edid,
> {
> const u8 *displayid = drm_find_edid_extension(drm_edid, DISPLAYID_EXT, ext_index);
> const struct displayid_header *base;
> - int ret;
>
> if (!displayid)
> return NULL;
> @@ -63,11 +63,10 @@ static const u8 *drm_find_displayid_extension(const struct drm_edid *drm_edid,
> *length = EDID_LENGTH - 1;
> *idx = 1;
>
> - ret = validate_displayid(displayid, *length, *idx);
> - if (ret)
> + base = validate_displayid(displayid, *length, *idx);
> + if (IS_ERR(base))
> return NULL;
>
> - base = (const struct displayid_header *)&displayid[*idx];
> *length = *idx + sizeof(*base) + base->bytes;
>
> return displayid;
Tested-by: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx>
Reviewed-by: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx>
--
Best regards,
Dmitry
