[PATCH 08/24] timekeeping: Encapsulate locking/unlocking of timekeeper_lock

Anna-Maria Behnsen
2024-09-11T13:30:06Z

From: Thomas Gleixner <tglx@linutronix.de>

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>
---
kernel/time/timekeeping.c | 15 ++++++++++++++-
kernel/time/timekeeping_internal.h | 3 ++-
kernel/time/vsyscall.c | 5 ++---
3 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index e35e00b0cdd4..e0b6d088a33b 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -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);
+}
+
static inline void tk_normalize_xtime(struct timekeeper *tk)
{
while (tk->tkr_mono.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_mono.shift)) {
diff --git a/kernel/time/timekeeping_internal.h b/kernel/time/timekeeping_internal.h
index 4ca2787d1642..3babb2bac579 100644
--- a/kernel/time/timekeeping_internal.h
+++ b/kernel/time/timekeeping_internal.h
@@ -34,6 +34,7 @@ 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 */
diff --git a/kernel/time/vsyscall.c b/kernel/time/vsyscall.c
index 9193d6133e5d..98488b20b594 100644
--- a/kernel/time/vsyscall.c
+++ b/kernel/time/vsyscall.c
@@ -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);
}

--
2.39.2