[PATCH] sched/clock: Provide !HAVE_UNSTABLE_SCHED_CLOCK stub for sched_clock_stable()

[Yiyang Chen <cyyzero16@gmail.com>]

When CONFIG_HAVE_UNSTABLE_SCHED_CLOCK is disabled, sched_clock() is
already assumed to provide stable semantics, but the public header
doesn't provide a sched_clock_stable() stub for that case.

Add a header stub that always returns true and clean up the duplicate
local stub in ring_buffer.c, so callers can use sched_clock_stable()
unconditionally.

Signed-off-by: Yiyang Chen <cyyzero16@gmail.com>
---
 include/linux/sched/clock.h | 5 +++++
 kernel/trace/ring_buffer.c  | 7 -------
 2 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/include/linux/sched/clock.h b/include/linux/sched/clock.h
index 196f0ca351a2..39f0a7f94bfc 100644
--- a/include/linux/sched/clock.h
+++ b/include/linux/sched/clock.h
@@ -33,6 +33,11 @@ extern u64 sched_clock_cpu(int cpu);
 extern void sched_clock_init(void);
 
 #ifndef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
+static inline int sched_clock_stable(void)
+{
+	return 1;
+}
+
 static inline void sched_clock_tick(void)
 {
 }
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 5326924615a4..02691c3c6dd6 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -3769,13 +3769,6 @@ rb_add_time_stamp(struct ring_buffer_per_cpu *cpu_buffer,
 	return skip_time_extend(event);
 }
 
-#ifndef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
-static inline bool sched_clock_stable(void)
-{
-	return true;
-}
-#endif
-
 static void
 rb_check_timestamp(struct ring_buffer_per_cpu *cpu_buffer,
 		   struct rb_event_info *info)
-- 
2.43.0