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timekeeping: Encapsulate locking/unlocking of timekeeper_lock

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timekeeper_lock protects updates of timekeeper (tk_core). It is also used
by vdso_update_begin/end() and not only internally by the timekeeper code.

As long as there is only a single timekeeper, this works fine.  But when
the timekeeper infrastructure will be reused for per ptp clock timekeepers,
timekeeper_lock needs to be part of tk_core..

Therefore encapuslate locking/unlocking of timekeeper_lock and make the
lock static.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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-v2-8-554456a44a15@linutronix.de
This commit is contained in:
Thomas Gleixner 2024-10-09 10:29:01 +02:00
parent 20c7b582e8
commit dbdcf8c4ca
3 changed files with 18 additions and 5 deletions
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15
kernel/time/timekeeping.c
View File

@ -41,7 +41,7 @@ enum timekeeping_adv_mode {
TK_ADV_FREQ
};
DEFINE_RAW_SPINLOCK(timekeeper_lock);
static DEFINE_RAW_SPINLOCK(timekeeper_lock);
/*
* The most important data for readout fits into a single 64 byte
@ -114,6 +114,19 @@ static struct tk_fast tk_fast_raw ____cacheline_aligned = {
.base[1] = FAST_TK_INIT,
};
unsigned long timekeeper_lock_irqsave(void)
{
unsigned long flags;
raw_spin_lock_irqsave(&timekeeper_lock, flags);
return flags;
}
void timekeeper_unlock_irqrestore(unsigned long flags)
{
raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
}
/*
* Multigrain timestamps require tracking the latest fine-grained timestamp
* that has been issued, and never returning a coarse-grained timestamp that is

3
kernel/time/timekeeping_internal.h
View File

@ -49,6 +49,7 @@ static inline u64 clocksource_delta(u64 now, u64 last, u64 mask)
#endif
/* Semi public for serialization of non timekeeper VDSO updates. */
extern raw_spinlock_t timekeeper_lock;
unsigned long timekeeper_lock_irqsave(void);
void timekeeper_unlock_irqrestore(unsigned long flags);
#endif /* _TIMEKEEPING_INTERNAL_H */

5
kernel/time/vsyscall.c
View File

@ -151,9 +151,8 @@ void update_vsyscall_tz(void)
unsigned long vdso_update_begin(void)
{
struct vdso_data *vdata = __arch_get_k_vdso_data();
unsigned long flags;
unsigned long flags = timekeeper_lock_irqsave();
raw_spin_lock_irqsave(&timekeeper_lock, flags);
vdso_write_begin(vdata);
return flags;
}
@ -172,5 +171,5 @@ void vdso_update_end(unsigned long flags)
vdso_write_end(vdata);
__arch_sync_vdso_data(vdata);
raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
timekeeper_unlock_irqrestore(flags);
}