[tip:sched/core] sched/prio: Add two inline function named nice_to_rlimit() and rlimit_to_nice() in prio.h.

[tip-bot for Dongsheng Yang <tipbot@zytor.com>]

Commit-ID:  b482e5f5c22ef95ffe7c4d86fc9719455fb24bca
Gitweb:     http://git.kernel.org/tip/b482e5f5c22ef95ffe7c4d86fc9719455fb24bca
Author:     Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
AuthorDate: Thu, 8 May 2014 18:33:48 +0900
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Mon, 19 May 2014 22:02:42 +0900

sched/prio: Add two inline function named nice_to_rlimit() and rlimit_to_nice() in prio.h.

This patch add two inline functions named nice_to_rlimit() and
rlimit_to_nice() in prio.h.  They are handle the convertion between
nice value [19,-20] and rlimit style value [1,40].

Cc: mingo@redhat.com
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/e1f9c9f2023719e0738e16cd6807c74c68b08fad.1399532322.git.yangds.fnst@cn.fujitsu.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 include/linux/sched/prio.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/include/linux/sched/prio.h b/include/linux/sched/prio.h
index ac32258..d9cf5a5 100644
--- a/include/linux/sched/prio.h
+++ b/include/linux/sched/prio.h
@@ -41,4 +41,20 @@
 #define TASK_USER_PRIO(p)	USER_PRIO((p)->static_prio)
 #define MAX_USER_PRIO		(USER_PRIO(MAX_PRIO))
 
+/*
+ * Convert nice value [19,-20] to rlimit style value [1,40].
+ */
+static inline long nice_to_rlimit(long nice)
+{
+	return (MAX_NICE - nice + 1);
+}
+
+/*
+ * Convert rlimit style value [1,40] to nice value [-20, 19].
+ */
+static inline long rlimit_to_nice(long prio)
+{
+	return (MAX_NICE - prio + 1);
+}
+
 #endif /* _SCHED_PRIO_H */