Commit dbdcf8c4 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

timekeeping: Encapsulate locking/unlocking of timekeeper_lock 



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: 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-v2-8-554456a44a15@linutronix.de
parent 20c7b582

kernel/time/timekeeping.c

+14 −1
Original line number Diff line number Diff line
@@ -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

kernel/time/timekeeping_internal.h

+2 −1
Original line number Diff line number Diff line
@@ -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 */

kernel/time/vsyscall.c

+2 −3
Original line number Diff line number Diff line
@@ -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);

}