Re: [PATCH 11/99] fbdev/aty: Duplicate video-mode option string

[Geert Uytterhoeven]

Hi Thomas,

Thanks for your patch!

On Mon, Mar 6, 2023 at 5:00 PM Thomas Zimmermann <tzimmermann@xxxxxxx> wrote:
> Assume that the driver does not own the option string or its substrings
> and hence duplicate the option string for the video mode. The driver only
> parses the option string once as part of module initialization, so use
> a static buffer to store the duplicated mode option. Linux automatically
> frees the memory upon releasing the module.

Are you sure about that?
All of this code is inside "#ifndef MODULE".
In the aty128fb case, the function is not marked __init.
Enabling these 3 drivers adds 3x256 bytes of static buffer, more
if you enable more fbdev drivers.

> Done in preparation of switching the driver to struct option_iter and
> constifying the option string.
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>

> --- a/drivers/video/fbdev/aty/aty128fb.c
> +++ b/drivers/video/fbdev/aty/aty128fb.c
> @@ -1723,7 +1723,17 @@ static int aty128fb_setup(char *options)
>                         continue;
>                 }
>  #endif /* CONFIG_PPC_PMAC */
> -               mode_option = this_opt;
> +               {
> +                       static char mode_option_buf[256];
> +                       int ret;
> +
> +                       ret = snprintf(mode_option_buf, sizeof(mode_option_buf), "%s", this_opt);
> +                       if (WARN(ret < 0, "aty128: ignoring invalid option, ret=%d\n", ret))
> +                               continue;
> +                       if (WARN(ret >= sizeof(mode_option_buf), "aty128fb: option too long\n"))
> +                               continue;
> +                       mode_option = mode_option_buf;
> +               }
>         }
>         return 0;
>  }
eturn 0;
>  }

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds