sched: Use clamp() and clamp_val() to make sys_nice() more readable

Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1399541715-19568-1-git-send-email-yangds.fnst@cn.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 2 insertions, 9 deletions

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 6340c601475d..f5605b6deea4 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3057,17 +3057,10 @@ SYSCALL_DEFINE1(nice, int, increment)
          * We don't have to worry. Conceptually one call occurs first
          * and we have a single winner.
          */
-        if (increment < -40)
-                increment = -40;
-        if (increment > 40)
-                increment = 40;
-
+        increment = clamp(increment, -NICE_WIDTH, NICE_WIDTH);
         nice = task_nice(current) + increment;
-        if (nice < MIN_NICE)
-                nice = MIN_NICE;
-        if (nice > MAX_NICE)
-                nice = MAX_NICE;
 
+        nice = clamp_val(nice, MIN_NICE, MAX_NICE);
         if (increment < 0 && !can_nice(current, nice))
                 return -EPERM;