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Subject[PATCH] sched: fix never executed code due to expression always false

There are two expressions in kernel/sched.c that are always false since
they test for <0 but the result of the expression is unsigned so they will
never be less than zero. This patch implement the logic that I believe is
intended without the signedness issue and without the nasty casts.
<disclaimer>patch is compile tested only</disclaimer>


Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk>
---
sched.c | 7 ++++---
1 files changed, 4 insertions(+), 3 deletions(-)
--- linux-2.6.12-rc2-mm3-orig/kernel/sched.c 2005-04-11 21:20:56.000000000 +0200
+++ linux-2.6.12-rc2-mm3/kernel/sched.c 2005-04-15 01:37:48.000000000 +0200
@@ -2697,9 +2697,10 @@ need_resched_nonpreemptible:
schedstat_inc(rq, sched_cnt);
now = sched_clock();
if (likely((long long)now - prev->timestamp < NS_MAX_SLEEP_AVG)) {
- run_time = now - prev->timestamp;
- if (unlikely((long long)now - prev->timestamp < 0))
+ if (unlikely(prev->timestamp > now))
run_time = 0;
+ else
+ run_time = now - prev->timestamp;
} else
run_time = NS_MAX_SLEEP_AVG;

@@ -2776,7 +2777,7 @@ go_idle:

if (!rt_task(next) && next->activated > 0) {
unsigned long long delta = now - next->timestamp;
- if (unlikely((long long)now - next->timestamp < 0))
+ if (unlikely(next->timestamp > now))
delta = 0;

if (next->activated == 1)

-
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