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: 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

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 848d2b18f8002a667c7ed39c3f9ce0e44b1bdb7a..77e0a0fe77717ff04bb000c208219e8199e7cca8 100644 (file)
--- 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);
+}
+
 /*
  * Multigrain timestamps require tracking the latest fine-grained timestamp
  * that has been issued, and never returning a coarse-grained timestamp that is

diff --git a/kernel/time/timekeeping_internal.h b/kernel/time/timekeeping_internal.h
index 0bbae825bc0226e4eed64e73fe3b454986c7573f..b3dca834f48ca85f6e7bbd355ab63921ebe3bb41 100644 (file)
--- a/kernel/time/timekeeping_internal.h
+++ b/kernel/time/timekeeping_internal.h
@@ -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 */

diff --git a/kernel/time/vsyscall.c b/kernel/time/vsyscall.c
index 9193d6133e5d688342be8485b9a0efb7af9ee148..98488b20b594e6ad6b3a89a728b435de9654141a 100644 (file)
--- 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);
 }