Commit c2a32956 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

timekeeping: Simplify code in timekeeping_advance() 



timekeeping_advance() takes the timekeeper_lock and releases it before
returning. When an early return is required, goto statements are used to
make sure the lock is realeased properly. When the code was written the
locking guard() was not yet available.

Use the guard() to simplify the code and while at it cleanup ordering of
function variables. No functional change.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarAnna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarJohn Stultz <jstultz@google.com>
Link: https://lore.kernel.org/all/20241009-devel-anna-maria-b4-timers-ptp-timekeeping-v2-5-554456a44a15@linutronix.de
parent 1f7226b1

kernel/time/timekeeping.c

+6 −10
Original line number Diff line number Diff line
@@ -2307,23 +2307,22 @@ static bool timekeeping_advance(enum timekeeping_adv_mode mode) 
{

	struct timekeeper *real_tk = &tk_core.timekeeper;

	struct timekeeper *tk = &shadow_timekeeper;

	u64 offset;

	int shift = 0, maxshift;

	unsigned int clock_set = 0;

	unsigned long flags;

	int shift = 0, maxshift;

	u64 offset;



	raw_spin_lock_irqsave(&timekeeper_lock, flags);

	guard(raw_spinlock_irqsave)(&timekeeper_lock);



	/* Make sure we're fully resumed: */

	if (unlikely(timekeeping_suspended))

		goto out;

		return false;



	offset = clocksource_delta(tk_clock_read(&tk->tkr_mono),

				   tk->tkr_mono.cycle_last, tk->tkr_mono.mask);



	/* Check if there's really nothing to do */

	if (offset < real_tk->cycle_interval && mode == TK_ADV_TICK)

		goto out;

		return false;



	/* Do some additional sanity checking */

	timekeeping_check_update(tk, offset);
@@ -2342,8 +2341,7 @@ static bool timekeeping_advance(enum timekeeping_adv_mode mode) 
	maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1;

	shift = min(shift, maxshift);

	while (offset >= tk->cycle_interval) {

		offset = logarithmic_accumulation(tk, offset, shift,

							&clock_set);

		offset = logarithmic_accumulation(tk, offset, shift, &clock_set);

		if (offset < tk->cycle_interval<<shift)

			shift--;

	}
@@ -2372,8 +2370,6 @@ static bool timekeeping_advance(enum timekeeping_adv_mode mode) 
	memcpy(real_tk, tk, sizeof(*tk));

	/* The memcpy must come last. Do not put anything here! */

	write_seqcount_end(&tk_core.seq);

out:

	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);



	return !!clock_set;

}