apply_lut_to_channel_value() indexes a struct drm_color_lut array, and then cast to (__u16 *) and index with the channel (r -> index 0, g -> index 1, b -> index 2). This is a bit fragile and prone to issues.
Instead, add a more robust helper lut_channel_value() such that, given a struct drm_color_lut and a color channel, it retrives the value. Signed-off-by: Leandro Ribeiro <[email protected]> --- drivers/gpu/drm/vkms/vkms_composer.c | 30 ++++++++++++++++++++++------ 1 file changed, 24 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c index 83d217085ad0..bd539ee4c5be 100644 --- a/drivers/gpu/drm/vkms/vkms_composer.c +++ b/drivers/gpu/drm/vkms/vkms_composer.c @@ -75,6 +75,24 @@ VISIBLE_IF_KUNIT u16 lerp_u16(u16 a, u16 b, s64 t) } EXPORT_SYMBOL_IF_KUNIT(lerp_u16); +static inline u16 lut_channel_value(const struct drm_color_lut *lut, + enum lut_channel channel) +{ + switch (channel) { + case LUT_RED: + return lut->red; + case LUT_BLUE: + return lut->blue; + case LUT_GREEN: + return lut->green; + case LUT_RESERVED: + DRM_DEBUG_DRIVER("LUT_RESERVED channel should not be accessed"); + return 0; + } + DRM_DEBUG_DRIVER("unknown LUT channel"); + return 0; +} + VISIBLE_IF_KUNIT s64 get_lut_index(const struct vkms_color_lut *lut, u16 channel_value) { s64 color_channel_fp = drm_int2fixp(channel_value); @@ -86,8 +104,8 @@ EXPORT_SYMBOL_IF_KUNIT(get_lut_index); VISIBLE_IF_KUNIT u16 apply_lut_to_channel_value(const struct vkms_color_lut *lut, u16 channel_value, enum lut_channel channel) { + const struct drm_color_lut *lut_y_floor, *lut_y_ceil; s64 lut_index = get_lut_index(lut, channel_value); - u16 *floor_lut_value, *ceil_lut_value; u16 floor_channel_value, ceil_channel_value; /* @@ -96,15 +114,15 @@ VISIBLE_IF_KUNIT u16 apply_lut_to_channel_value(const struct vkms_color_lut *lut */ static_assert(sizeof(struct drm_color_lut) == sizeof(__u16) * 4); - floor_lut_value = (__u16 *)&lut->base[drm_fixp2int(lut_index)]; + lut_y_floor = &lut->base[drm_fixp2int(lut_index)]; if (drm_fixp2int(lut_index) == (lut->lut_length - 1)) /* We're at the end of the LUT array, use same value for ceil and floor */ - ceil_lut_value = floor_lut_value; + lut_y_ceil = lut_y_floor; else - ceil_lut_value = (__u16 *)&lut->base[drm_fixp2int_ceil(lut_index)]; + lut_y_ceil = &lut->base[drm_fixp2int_ceil(lut_index)]; - floor_channel_value = floor_lut_value[channel]; - ceil_channel_value = ceil_lut_value[channel]; + floor_channel_value = lut_channel_value(lut_y_floor, channel); + ceil_channel_value = lut_channel_value(lut_y_ceil, channel); return lerp_u16(floor_channel_value, ceil_channel_value, lut_index & DRM_FIXED_DECIMAL_MASK); -- 2.55.0
