kernel core: use helpers for rlimits

Make sure compiler won't do weird things with limits.  E.g.  fetching them
twice may return 2 different values after writable limits are implemented.

I.e.  either use rlimit helpers added in commit 3e10e716abf3 ("resource:
add helpers for fetching rlimits") or ACCESS_ONCE if not applicable.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index abb36b16b93b..b47ceeec1a91 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4353,7 +4353,7 @@ int can_nice(const struct task_struct *p, const int nice)
         /* convert nice value [19,-20] to rlimit style value [1,40] */
         int nice_rlim = 20 - nice;
 
-        return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur ||
+        return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) ||
                 capable(CAP_SYS_NICE));
 }
 
@@ -4530,7 +4530,7 @@ recheck:
 
                         if (!lock_task_sighand(p, &flags))
                                 return -ESRCH;
-                        rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur;
+                        rlim_rtprio = task_rlimit(p, RLIMIT_RTPRIO);
                         unlock_task_sighand(p, &flags);
 
                         /* can't set/change the rt policy */