| Message ID | 51ECE851.4030002@asianux.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Jul 22, 2013 at 10:07 AM, Chen Gang <gang.chen@asianux.com> 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@asianux.com> > --- > 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@linux-m68k.org 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 -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 07/22/2013 07:16 PM, Geert Uytterhoeven wrote: > On Mon, Jul 22, 2013 at 10:07 AM, Chen Gang <gang.chen@asianux.com> 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@asianux.com> >> --- >> 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". > OH, yes, thanks. Original implementation is no issue (the compiler will skip the first checking automatically). If suitable, I should send patch v2. Thanks. > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org > > 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 > >
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; if (!registered_fb[con2fb.framebuffer]) request_module("fb%d", con2fb.framebuffer);
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@asianux.com> --- drivers/video/fbmem.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)