[PATCH v8 3/8] time: Remove duplicated code in ktime_get_raw_and_real()

Christopher S. Hall
2016-02-22T11:15:21Z

The code in ktime_get_snapshot() is a superset of the code in
ktime_get_raw_and_real() code. Further, ktime_get_raw_and_real() is
called only by the PPS code, pps_get_ts(). Consolidate the
pps_get_ts() code into a single function calling ktime_get_snapshot()
and eliminate ktime_get_raw_and_real(). A side effect of this is that
the raw and real results of pps_get_ts() correspond to exactly the
same clock cycle. Previously these values represented separate reads
of the system clock.

Signed-off-by: Christopher S. Hall <christopher.s.hall@intel.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
include/linux/pps_kernel.h | 17 ++++++-----------
kernel/time/timekeeping.c | 40 ++--------------------------------------
2 files changed, 8 insertions(+), 49 deletions(-)

diff --git a/include/linux/pps_kernel.h b/include/linux/pps_kernel.h
index 54bf148..35ac903 100644
--- a/include/linux/pps_kernel.h
+++ b/include/linux/pps_kernel.h
@@ -111,22 +111,17 @@ static inline void timespec_to_pps_ktime(struct pps_ktime *kt,
kt->nsec = ts.tv_nsec;
}

-#ifdef CONFIG_NTP_PPS
-
static inline void pps_get_ts(struct pps_event_time *ts)
{
- ktime_get_raw_and_real_ts64(&ts->ts_raw, &ts->ts_real);
-}
+ struct system_time_snapshot snap;

-#else /* CONFIG_NTP_PPS */
-
-static inline void pps_get_ts(struct pps_event_time *ts)
-{
- ktime_get_real_ts64(&ts->ts_real);
+ ktime_get_snapshot(&snap);
+ ts->ts_real = ktime_to_timespec64(snap.real);
+#ifdef CONFIG_NTP_PPS
+ ts->ts_raw = ktime_to_timespec64(snap.raw);
+#endif
}

-#endif /* CONFIG_NTP_PPS */
-
/* Subtract known time delay from PPS event time(s) */
static inline void pps_sub_ts(struct pps_event_time *ts, struct timespec64 delta)
{
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 89b4695..f1a1c97 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -888,6 +888,8 @@ void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot)
s64 nsec_real;
cycle_t now;

+ WARN_ON(timekeeping_suspended);
+
do {
seq = read_seqcount_begin(&tk_core.seq);

@@ -905,44 +907,6 @@ void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot)
}
EXPORT_SYMBOL_GPL(ktime_get_snapshot);

-#ifdef CONFIG_NTP_PPS
-
-/**
- * ktime_get_raw_and_real_ts64 - get day and raw monotonic time in timespec format
- * @ts_raw: pointer to the timespec to be set to raw monotonic time
- * @ts_real: pointer to the timespec to be set to the time of day
- *
- * This function reads both the time of day and raw monotonic time at the
- * same time atomically and stores the resulting timestamps in timespec
- * format.
- */
-void ktime_get_raw_and_real_ts64(struct timespec64 *ts_raw, struct timespec64 *ts_real)
-{
- struct timekeeper *tk = &tk_core.timekeeper;
- unsigned long seq;
- s64 nsecs_raw, nsecs_real;
-
- WARN_ON_ONCE(timekeeping_suspended);
-
- do {
- seq = read_seqcount_begin(&tk_core.seq);
-
- *ts_raw = tk->raw_time;
- ts_real->tv_sec = tk->xtime_sec;
- ts_real->tv_nsec = 0;
-
- nsecs_raw = timekeeping_get_ns(&tk->tkr_raw);
- nsecs_real = timekeeping_get_ns(&tk->tkr_mono);
-
- } while (read_seqcount_retry(&tk_core.seq, seq));
-
- timespec64_add_ns(ts_raw, nsecs_raw);
- timespec64_add_ns(ts_real, nsecs_real);
-}
-EXPORT_SYMBOL(ktime_get_raw_and_real_ts64);
-
-#endif /* CONFIG_NTP_PPS */
-
/**
* do_gettimeofday - Returns the time of day in a timeval
* @tv: pointer to the timeval to be set
--
2.1.4