On Mon, Jul 22, 2013 at 10:07 AM, Chen Gang <gang.chen@xxxxxxxxxxx> wrote:
> For 'con2fb.framebuffer', it can be '-1' as an invalid value, so it
> need related type cast for its comparing.
>
> The related warning:
>
> drivers/video/fbmem.c:1169:3: warning: comparison of unsigned expression < 0 is always false [-Wtype-limits]
>
>
> Signed-off-by: Chen Gang <gang.chen@xxxxxxxxxxx>
> ---
> drivers/video/fbmem.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c
> index 36e1fe2..8e8225c 100644
> --- a/drivers/video/fbmem.c
> +++ b/drivers/video/fbmem.c
> @@ -1166,7 +1166,7 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
> return -EFAULT;
> if (con2fb.console < 1 || con2fb.console > MAX_NR_CONSOLES)
> return -EINVAL;
> - if (con2fb.framebuffer < 0 || con2fb.framebuffer >= FB_MAX)
> + if ((int)con2fb.framebuffer < 0 || con2fb.framebuffer >= FB_MAX)
> return -EINVAL;
Instead of adding the cast, you can also just remove the check, as it's useless.
If it's `-1' for invalid, after conversion to unsigned, it will
trigger the check
">= FB_MAX".
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
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