Re: [PATCH v5 06/16] drm/vkms: Use const for input pointers in pixel_read an pixel_write functions

[Maíra Canal]

On 3/13/24 14:45, Louis Chauvet wrote:
> As the pixel_read and pixel_write function should never modify the input
> buffer, mark those pointers const.
>
> Signed-off-by: Louis Chauvet <louis.chauvet@xxxxxxxxxxx>

Reviewed-by: Maíra Canal <mcanal@xxxxxxxxxx>

Best Regards,
- Maíra

> ---
>   drivers/gpu/drm/vkms/vkms_drv.h     |  4 ++--
>   drivers/gpu/drm/vkms/vkms_formats.c | 24 ++++++++++++------------
>   2 files changed, 14 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
> index 4bfc62d26f08..3ead8b39af4a 100644
> --- a/drivers/gpu/drm/vkms/vkms_drv.h
> +++ b/drivers/gpu/drm/vkms/vkms_drv.h
> @@ -61,7 +61,7 @@ struct line_buffer {
>    * @out_pixel: destination address to write the pixel
>    * @in_pixel: pixel to write
>    */
> -typedef void (*pixel_write_t)(u8 *out_pixel, struct pixel_argb_u16 *in_pixel);
> +typedef void (*pixel_write_t)(u8 *out_pixel, const struct pixel_argb_u16 *in_pixel);
>   
>   struct vkms_writeback_job {
>   	struct iosys_map data[DRM_FORMAT_MAX_PLANES];
> @@ -76,7 +76,7 @@ struct vkms_writeback_job {
>    * @in_pixel: Pointer to the pixel to read
>    * @out_pixel: Pointer to write the converted pixel
>    */
> -typedef void (*pixel_read_t)(u8 *in_pixel, struct pixel_argb_u16 *out_pixel);
> +typedef void (*pixel_read_t)(const u8 *in_pixel, struct pixel_argb_u16 *out_pixel);
>   
>   /**
>    * vkms_plane_state - Driver specific plane state
> diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
> index b57d85b8b935..b2f8dfc26c35 100644
> --- a/drivers/gpu/drm/vkms/vkms_formats.c
> +++ b/drivers/gpu/drm/vkms/vkms_formats.c
> @@ -76,7 +76,7 @@ static int get_x_position(const struct vkms_frame_info *frame_info, int limit, i
>    * They are used in the `vkms_compose_row` function to handle multiple formats.
>    */
>   
> -static void ARGB8888_to_argb_u16(u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
> +static void ARGB8888_to_argb_u16(const u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
>   {
>   	/*
>   	 * The 257 is the "conversion ratio". This number is obtained by the
> @@ -90,7 +90,7 @@ static void ARGB8888_to_argb_u16(u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
>   	out_pixel->b = (u16)in_pixel[0] * 257;
>   }
>   
> -static void XRGB8888_to_argb_u16(u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
> +static void XRGB8888_to_argb_u16(const u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
>   {
>   	out_pixel->a = (u16)0xffff;
>   	out_pixel->r = (u16)in_pixel[2] * 257;
> @@ -98,7 +98,7 @@ static void XRGB8888_to_argb_u16(u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
>   	out_pixel->b = (u16)in_pixel[0] * 257;
>   }
>   
> -static void ARGB16161616_to_argb_u16(u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
> +static void ARGB16161616_to_argb_u16(const u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
>   {
>   	u16 *pixel = (u16 *)in_pixel;
>   
> @@ -108,7 +108,7 @@ static void ARGB16161616_to_argb_u16(u8 *in_pixel, struct pixel_argb_u16 *out_pi
>   	out_pixel->b = le16_to_cpu(pixel[0]);
>   }
>   
> -static void XRGB16161616_to_argb_u16(u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
> +static void XRGB16161616_to_argb_u16(const u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
>   {
>   	u16 *pixel = (u16 *)in_pixel;
>   
> @@ -118,7 +118,7 @@ static void XRGB16161616_to_argb_u16(u8 *in_pixel, struct pixel_argb_u16 *out_pi
>   	out_pixel->b = le16_to_cpu(pixel[0]);
>   }
>   
> -static void RGB565_to_argb_u16(u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
> +static void RGB565_to_argb_u16(const u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
>   {
>   	u16 *pixel = (u16 *)in_pixel;
>   
> @@ -143,7 +143,7 @@ static void RGB565_to_argb_u16(u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
>    * It is used to avoid null pointer to be used as a function. In theory, this function should
>    * never be called, except if you found a bug in the driver/DRM core.
>    */
> -static void black_to_argb_u16(u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
> +static void black_to_argb_u16(const u8 *in_pixel, struct pixel_argb_u16 *out_pixel)
>   {
>   	out_pixel->a = (u16)0xFFFF;
>   	out_pixel->r = 0;
> @@ -189,7 +189,7 @@ void vkms_compose_row(struct line_buffer *stage_buffer, struct vkms_plane_state
>    * They are used in the `vkms_writeback_row` to convert and store a pixel from the src_buffer to
>    * the writeback buffer.
>    */
> -static void argb_u16_to_ARGB8888(u8 *out_pixel, struct pixel_argb_u16 *in_pixel)
> +static void argb_u16_to_ARGB8888(u8 *out_pixel, const struct pixel_argb_u16 *in_pixel)
>   {
>   	/*
>   	 * This sequence below is important because the format's byte order is
> @@ -207,7 +207,7 @@ static void argb_u16_to_ARGB8888(u8 *out_pixel, struct pixel_argb_u16 *in_pixel)
>   	out_pixel[0] = DIV_ROUND_CLOSEST(in_pixel->b, 257);
>   }
>   
> -static void argb_u16_to_XRGB8888(u8 *out_pixel, struct pixel_argb_u16 *in_pixel)
> +static void argb_u16_to_XRGB8888(u8 *out_pixel, const struct pixel_argb_u16 *in_pixel)
>   {
>   	out_pixel[3] = 0xff;
>   	out_pixel[2] = DIV_ROUND_CLOSEST(in_pixel->r, 257);
> @@ -215,7 +215,7 @@ static void argb_u16_to_XRGB8888(u8 *out_pixel, struct pixel_argb_u16 *in_pixel)
>   	out_pixel[0] = DIV_ROUND_CLOSEST(in_pixel->b, 257);
>   }
>   
> -static void argb_u16_to_ARGB16161616(u8 *out_pixel, struct pixel_argb_u16 *in_pixel)
> +static void argb_u16_to_ARGB16161616(u8 *out_pixel, const struct pixel_argb_u16 *in_pixel)
>   {
>   	u16 *pixel = (u16 *)out_pixel;
>   
> @@ -225,7 +225,7 @@ static void argb_u16_to_ARGB16161616(u8 *out_pixel, struct pixel_argb_u16 *in_pi
>   	pixel[0] = cpu_to_le16(in_pixel->b);
>   }
>   
> -static void argb_u16_to_XRGB16161616(u8 *out_pixel, struct pixel_argb_u16 *in_pixel)
> +static void argb_u16_to_XRGB16161616(u8 *out_pixel, const struct pixel_argb_u16 *in_pixel)
>   {
>   	u16 *pixel = (u16 *)out_pixel;
>   
> @@ -235,7 +235,7 @@ static void argb_u16_to_XRGB16161616(u8 *out_pixel, struct pixel_argb_u16 *in_pi
>   	pixel[0] = cpu_to_le16(in_pixel->b);
>   }
>   
> -static void argb_u16_to_RGB565(u8 *out_pixel, struct pixel_argb_u16 *in_pixel)
> +static void argb_u16_to_RGB565(u8 *out_pixel, const struct pixel_argb_u16 *in_pixel)
>   {
>   	u16 *pixel = (u16 *)out_pixel;
>   
> @@ -260,7 +260,7 @@ static void argb_u16_to_RGB565(u8 *out_pixel, struct pixel_argb_u16 *in_pixel)
>    * It is used to avoid null pointer to be used as a function. In theory, this should never
>    * happen, except if there is a bug in the driver
>    */
> -static void argb_u16_to_nothing(u8 *out_pixel, struct pixel_argb_u16 *in_pixel)
> +static void argb_u16_to_nothing(u8 *out_pixel, const struct pixel_argb_u16 *in_pixel)
>   {}
>   
>   /**