diff mbox series

[14/24] timekeeping: Provide timekeeping_restore_shadow()

Message ID 20240911-devel-anna-maria-b4-timers-ptp-timekeeping-v1-14-f7cae09e25d6@linutronix.de (mailing list archive)
State Not Applicable
Headers show
Series timekeeping: Rework to prepare support of indenpendent PTP clocks | expand

Checks

Context Check Description
netdev/tree_selection success Not a local patch

Commit Message

Anna-Maria Behnsen Sept. 11, 2024, 1:29 p.m. UTC 
From: Thomas Gleixner <tglx@linutronix.de>

Functions which operate on the real timekeeper, e.g. do_settimeofday(),
have error conditions. If they are hit a full timekeeping update is still
required because the already committed operations modified the timekeeper.

When switching these functions to operate on the shadow timekeeper then the
full update can be avoided in the error case, but the modified shadow
timekeeper has to be restored.

Provide a helper function for that.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
---
 kernel/time/timekeeping.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index a69850429fb4..345117ff665d 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -755,6 +755,15 @@  static inline void tk_update_ktime_data(struct timekeeper *tk)
 	tk->tkr_raw.base = ns_to_ktime(tk->raw_sec * NSEC_PER_SEC);
 }
 
+/*
+ * Restore the shadow timekeeper from the real timekeeper.
+ */
+static void timekeeping_restore_shadow(struct tk_data *tkd)
+{
+	lockdep_assert_held(&tkd->lock);
+	memcpy(&tkd->shadow_timekeeper, &tkd->timekeeper, sizeof(tkd->timekeeper));
+}
+
 static void timekeeping_update(struct tk_data *tkd, struct timekeeper *tk, unsigned int action)
 {
 	lockdep_assert_held(&tkd->lock);
@@ -782,7 +791,7 @@  static void timekeeping_update(struct tk_data *tkd, struct timekeeper *tk, unsig
 	 * timekeeper structure on the next update with stale data
 	 */
 	if (action & TK_MIRROR)
-		memcpy(&tkd->shadow_timekeeper, tk, sizeof(*tk));
+		timekeeping_restore_shadow(tkd);
 }
 
 static void timekeeping_update_staged(struct tk_data *tkd, unsigned int action)