sched: rt-watchdog: fix .rlim_max = RLIM_INFINITY

Remove the curious logic to set it_sched_expires in the future. It useless
because rt.timeout wouldn't be incremented anyway.

Explicity check for RLIM_INFINITY as a test programm that had a 1s soft limit
and a inf hard limit would SIGKILL at 1s. This is because RLIM_INFINITY+d-1
is d-2.

Signed-off-by: Peter Zijlsta <a.p.zijlstra@chello.nl>
CC: Michal Schmidt <mschmidt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 3 insertions, 8 deletions

diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 2c076b36c4f6..0b7c82ac467e 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -1020,7 +1020,8 @@ static void check_thread_timers(struct task_struct *tsk,
                 unsigned long hard = sig->rlim[RLIMIT_RTTIME].rlim_max;
                 unsigned long *soft = &sig->rlim[RLIMIT_RTTIME].rlim_cur;
 
-                if (tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) {
+                if (hard != RLIM_INFINITY &&
+                    tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) {
                         /*
                          * At the hard limit, we just die.
                          * No need to calculate anything else now.
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index f1f215db3bd0..2dac5ebb8bcb 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -1125,13 +1125,7 @@ static void watchdog(struct rq *rq, struct task_struct *p)
 
                 p->rt.timeout++;
                 next = DIV_ROUND_UP(min(soft, hard), USEC_PER_SEC/HZ);
-                if (next > p->rt.timeout) {
-                        u64 next_time = p->se.sum_exec_runtime;
-
-                        next_time += next * (NSEC_PER_SEC/HZ);
-                        if (p->it_sched_expires > next_time)
-                                p->it_sched_expires = next_time;
-                } else
+                if (p->rt.timeout > next)
                         p->it_sched_expires = p->se.sum_exec_runtime;
         }
 }