No.
Unsigned arithmetic is fine. The _correct_ way to test whether something
is in within
[ start , start+HZ ]
is to do
if (jiffies - start <= HZ)
try it. The C language guarantees that unsigned arithmetic works in a
"modulo power of two" fashion, which means that it _is_ ok to do
arithmetic on unsigned longs, and jiffy wrapping does not matter. No need
to cast to "signed" or anything else.
In short: It is wrong to do
if (jiffies <= start+HZ)
and it is _right_ to do
if (jiffies - start <= HZ)
(as long as "start" is "unsigned long" like jiffies).
Linus
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/