Augment rt_task() with is_realtime()

Whenever the kernel checks for rt_task() to avoid delaying real-time
tasks, we want it to also not delay LITMUS^RT tasks.  Hence, most
calls to rt_task() should be matched by an equivalent call to
is_realtime().

Notably, this affects the implementations of select() and nanosleep(),
which use timer_slack_ns when setting up timers for non-real-time
tasks.

1 files changed, 3 insertions, 1 deletions

diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 22f9156f19d2..d5a8e4db0bf9 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -58,6 +58,8 @@
 
 #include "tick-internal.h"
 
+#include <litmus/litmus.h> /* for is_realtime() */
+
 /*
  * The timer bases:
  *
@@ -1659,7 +1661,7 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
         unsigned long slack;
 
         slack = current->timer_slack_ns;
-        if (dl_task(current) || rt_task(current))
+        if (dl_task(current) || rt_task(current) || is_realtime(current))
                 slack = 0;
 
         hrtimer_init_on_stack(&t.timer, clockid, mode);