timekeeping: Provide ktime_mono_to_any()

ktime based conversion function to map a monotonic time stamp to a
different CLOCK.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>

1 files changed, 20 insertions, 0 deletions

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index e99350319eec..032e77a54a79 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -451,6 +451,26 @@ ktime_t ktime_get_with_offset(enum tk_offsets offs)
 EXPORT_SYMBOL_GPL(ktime_get_with_offset);
 
 /**
+ * ktime_mono_to_any() - convert mononotic time to any other time
+ * @tmono:      time to convert.
+ * @offs:       which offset to use
+ */
+ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs)
+{
+        ktime_t *offset = offsets[offs];
+        unsigned long seq;
+        ktime_t tconv;
+
+        do {
+                seq = read_seqcount_begin(&tk_core.seq);
+                tconv = ktime_add(tmono, *offset);
+        } while (read_seqcount_retry(&tk_core.seq, seq));
+
+        return tconv;
+}
+EXPORT_SYMBOL_GPL(ktime_mono_to_any);
+
+/**
  * ktime_get_ts64 - get the monotonic clock in timespec64 format
  * @ts:         pointer to timespec variable
  *