timekeeping: Rework do_settimeofday64() to use shadow_timekeeper

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Updates of the timekeeper can be done by operating on the shadow timekeeper
and afterwards copying the result into the real timekeeper. This has the
advantage, that the sequence count write protected region is kept as small
as possible.

Convert do_settimeofday64() to use this scheme.

That allows to use a scoped_guard() for locking the timekeeper lock as the
usage of the shadow timekeeper allows a rollback in the error case instead
of the full timekeeper update of the original code.

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-v2-16-554456a44a15@linutronix.de

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Anna-Maria Behnsen 2024-10-09 10:29:09 +02:00 • committed by Thomas Gleixner

parent 97e5379253

commit bba9898ef3

1 changed files with 16 additions and 26 deletions

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kernel/time/timekeeping.c

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