[PATCH] sched: Document that RT task priorities are 1â99

[Sebastian Andrzej Siewior]

John identified three files which claim that RT task priorities start at
zero. As far as I understand, 0 is used for DL and has nothing to do
wihich RT priorities as identified by the RT policy.

Correct the comment, valid RT priorities are in the range from 1 to 99.

Reported-by: John Ogness <john.ogness@xxxxxxxxxxxxx>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
 Documentation/scheduler/sched-rt-group.txt | 2 +-
 include/linux/sched/prio.h                 | 2 +-
 kernel/sched/cpupri.h                      | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/Documentation/scheduler/sched-rt-group.txt b/Documentation/scheduler/sched-rt-group.txt
index d8fce3e784574..23f8f8465a775 100644
--- a/Documentation/scheduler/sched-rt-group.txt
+++ b/Documentation/scheduler/sched-rt-group.txt
@@ -175,7 +175,7 @@ get their allocated time.
 
 Implementing SCHED_EDF might take a while to complete. Priority Inheritance is
 the biggest challenge as the current linux PI infrastructure is geared towards
-the limited static priority levels 0-99. With deadline scheduling you need to
+the limited static priority levels 1-99. With deadline scheduling you need to
 do deadline inheritance (since priority is inversely proportional to the
 deadline delta (deadline - now)).
 
diff --git a/include/linux/sched/prio.h b/include/linux/sched/prio.h
index 7d64feafc408e..6986c32356842 100644
--- a/include/linux/sched/prio.h
+++ b/include/linux/sched/prio.h
@@ -8,7 +8,7 @@
 
 /*
  * Priority of a process goes from 0..MAX_PRIO-1, valid RT
- * priority is 0..MAX_RT_PRIO-1, and SCHED_NORMAL/SCHED_BATCH
+ * priority is 1..MAX_RT_PRIO-1, and SCHED_NORMAL/SCHED_BATCH
  * tasks are in the range MAX_RT_PRIO..MAX_PRIO-1. Priority
  * values are inverted: lower p->prio value means higher priority.
  *
diff --git a/kernel/sched/cpupri.h b/kernel/sched/cpupri.h
index 7dc20a3232e72..40257a97fb8f2 100644
--- a/kernel/sched/cpupri.h
+++ b/kernel/sched/cpupri.h
@@ -5,7 +5,7 @@
 #define CPUPRI_INVALID		-1
 #define CPUPRI_IDLE		 0
 #define CPUPRI_NORMAL		 1
-/* values 2-101 are RT priorities 0-99 */
+/* values 2-101 are RT priorities 1-99 */
 
 struct cpupri_vec {
 	atomic_t		count;
-- 
2.20.1