timekeeping: Rework timekeeping_init() to use shadow_timekeeper

For timekeeping_init() the sequence count write held time is not relevant
and it could keep working on the real timekeeper, but there is no reason to
make it different from other timekeeper updates.

Convert it to operate on the shadow timekeeper.

Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <jstultz@google.com>
Link: https://lore.kernel.org/all/20241009-devel-anna-maria-b4-timers-ptp-timekeeping-v2-19-554456a44a15@linutronix.de

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index f77782f557ce9e5decfa4a0828c3d8c0d43f1d6d..4e0037d342d84ea99b07308bcb9c7f5f993b4148 100644 (file)
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1809,7 +1809,7 @@ static bool persistent_clock_exists;
 void __init timekeeping_init(void)
 {
        struct timespec64 wall_time, boot_offset, wall_to_mono;
-       struct timekeeper *tk = &tk_core.timekeeper;
+       struct timekeeper *tks = &tk_core.shadow_timekeeper;
        struct clocksource *clock;
 
        tkd_basic_setup(&tk_core);
@@ -1833,22 +1833,20 @@ void __init timekeeping_init(void)
        wall_to_mono = timespec64_sub(boot_offset, wall_time);
 
        guard(raw_spinlock_irqsave)(&tk_core.lock);
-       write_seqcount_begin(&tk_core.seq);
+
        ntp_init();
 
        clock = clocksource_default_clock();
        if (clock->enable)
                clock->enable(clock);
-       tk_setup_internals(tk, clock);
+       tk_setup_internals(tks, clock);
 
-       tk_set_xtime(tk, &wall_time);
-       tk->raw_sec = 0;
+       tk_set_xtime(tks, &wall_time);
+       tks->raw_sec = 0;
 
-       tk_set_wall_to_mono(tk, wall_to_mono);
+       tk_set_wall_to_mono(tks, wall_to_mono);
 
-       timekeeping_update(&tk_core, tk, TK_MIRROR | TK_CLOCK_WAS_SET);
-
-       write_seqcount_end(&tk_core.seq);
+       timekeeping_update_from_shadow(&tk_core, TK_CLOCK_WAS_SET);
 }
 
 /* time in seconds when suspend began for persistent clock */