Re: [B.A.T.M.A.N.] [PATCH] batman-adv: Fixing wrap-around bug in vis

[Andrew Lunn <andrew@lunn.ch>]

On Fri, Mar 12, 2010 at 01:09:31AM +0100, Linus L??ssing wrote:
> Sorry still does not seem to work :). Despite testing it on a
> setup in batman itself I also tested it with a small c program
> (which does not work as expected either):
> -----
> #include <stdio.h>
> #include <stdint.h>
> 
> #define seq_before(x,y) ((x - y) > 1 << 7 + 8 * (sizeof(x) - 1))
> #define seq_after(x,y) ((y - x) >= 1 << 7 + 8 * (sizeof(x) - 1))
> 
> int main() {
>         uint8_t old = 0;
>         uint8_t new = 1;
>         if (!seq_after(new,old))
>                 printf("foobar\n");
> 
>         return 0;
> }

It is worth taking a look at include/linux/jiffies.h. The macros
time_after(), time_after_eq() etc.

	      Andrew