On Wed, 23 May 2007, Patrick McHardy wrote:
>
> Yes, that looks better, thanks.
There appear to be other obvious problems in the recent "cleanups" in this
area..
Look at
psched_tdiff_bounded(psched_time_t tv1, psched_time_t tv2,
psched_time_t bound)
{
return min(tv1 - tv2, bound);
}
and compare it to the previous code:
#define PSCHED_TDIFF_SAFE(tv1, tv2, bound) \
min_t(long long, (tv1) - (tv2), bound)
and ponder how that "trivial cleanup" totally broke the thing.
Hint: "psched_time_t" is an "u64". What does that mean for
min(tv1 - tv2, bound);
again, when "tv2" is larger than tv1. It _used_ to return a negative
value. Now it returns a positive "bound" upper bound, because "tv1-tv2"
will be used as a huge unsigned (and thus _positive_) integer. And was
that accidental, or done on purpose?
Sounds accidental to me, since you then want to return a "psched_tdiff_t",
which is typedeffed to be "long".
Doesn't sound very safe to me, especially since the commit message for
this is "[NET_SCHED]: turn PSCHED_TDIFF_SAFE into inline function", and
there's no indication that anybody realized that it changed semantics in
the process.
Hmm? What _should_ that thing do?
Linus
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