[PATCH] sched: make policy-testing consistent in core

[Henrik Austad <henrik@austad.us>]

Most of the policy-tests are done via the <class>_policy() helpers with
the notable exception of idle. A new wrapper for valid_policy() has also
been added to improve readability  in set_load_weight().

This commit does not change the logical behavior of the scheduler core.

Signed-off-by: Henrik Austad <henrik@austad.us>
CC: Ingo Molnar <mingo@redhat.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: linux-kernel@vger.kernel.org
---
 kernel/sched/core.c  | 9 +++------
 kernel/sched/sched.h | 9 +++++++++
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 3595403921bd..889ce337a83a 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -814,7 +814,7 @@ static void set_load_weight(struct task_struct *p)
 	/*
 	 * SCHED_IDLE tasks get minimal weight:
 	 */
-	if (p->policy == SCHED_IDLE) {
+	if (idle_policy(p->policy)) {
 		load->weight = scale_load(WEIGHT_IDLEPRIO);
 		load->inv_weight = WMULT_IDLEPRIO;
 		return;
@@ -3736,10 +3736,7 @@ recheck:
 	} else {
 		reset_on_fork = !!(attr->sched_flags & SCHED_FLAG_RESET_ON_FORK);
 
-		if (policy != SCHED_DEADLINE &&
-				policy != SCHED_FIFO && policy != SCHED_RR &&
-				policy != SCHED_NORMAL && policy != SCHED_BATCH &&
-				policy != SCHED_IDLE)
+		if (!valid_policy(policy))
 			return -EINVAL;
 	}
 
@@ -3795,7 +3792,7 @@ recheck:
 		 * Treat SCHED_IDLE as nice 20. Only allow a switch to
 		 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
 		 */
-		if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) {
+		if (idle_policy(p->policy) && !idle_policy(policy)) {
 			if (!can_nice(p, task_nice(p)))
 				return -EPERM;
 		}
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 68cda117574c..597349055c3a 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -84,6 +84,10 @@ static inline void update_cpu_load_active(struct rq *this_rq) { }
  */
 #define RUNTIME_INF	((u64)~0ULL)
 
+static inline int idle_policy(int policy)
+{
+	return policy == SCHED_IDLE;
+}
 static inline int fair_policy(int policy)
 {
 	return policy == SCHED_NORMAL || policy == SCHED_BATCH;
@@ -98,6 +102,11 @@ static inline int dl_policy(int policy)
 {
 	return policy == SCHED_DEADLINE;
 }
+static inline bool valid_policy(int policy)
+{
+	return idle_policy(policy) || fair_policy(policy) ||
+		rt_policy(policy) || dl_policy(policy);
+}
 
 static inline int task_has_rt_policy(struct task_struct *p)
 {
-- 
1.9.1