On Monday, April 21, 2014 10:09:30 PM Pavel Machek wrote:
> On Mon 2014-04-21 21:40:27, Chen Gang wrote:
> > For do_div(), it need 'u64' type, which means the outside must be sure
> > of 'start' is not bigger than 'stop', or it will report warning.
> >
> > The related warning (with allmodconfig for unicore32):
> >
> > CC kernel/power/hibernate.o
> > kernel/power/hibernate.c: In function ‘swsusp_show_speed’:
> > kernel/power/hibernate.c:237: warning: comparison of distinct pointer
> > types lacks a cast
> >
> > Signed-off-by: Chen Gang <gang.chen.5...@gmail.com>
>
> > {
> > - s64 elapsed_centisecs64;
> > + u64 elapsed_centisecs64;
> > int centisecs;
> > int k;
> > int kps;
> >
> > elapsed_centisecs64 = timeval_to_ns(stop) - timeval_to_ns(start);
> > + if ((s64)elapsed_centisecs64 < 0) {
> > + printk(KERN_ERR "PM: stop: %llu < start %llu\n",
> > + timeval_to_ns(stop), timeval_to_ns(start));
> > + return;
> > + }
> > do_div(elapsed_centisecs64, NSEC_PER_SEC / 100);
> > centisecs = elapsed_centisecs64;
> > if (centisecs == 0)
>
> Quite a lot of code to shut up warning in mostly debugging
> function... is there alternative method of shutting it up? Have you
> seen < 0 values in wild?
No, I don't think so. This is a purely theoretical problem that never
happens in practice, because all of the callers do the right thing.
Rafael
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