From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed, 9 Oct 2024 08:29:01 +0000 (+0200)
Subject: timekeeping: Encapsulate locking/unlocking of timekeeper_lock
X-Git-Tag: v6.13-rc1~171^2~82
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=dbdcf8c4caeca8192daa43429ccf23a1feec126c;p=thirdparty%2Fkernel%2Flinux.git

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 848d2b18f8002..77e0a0fe77717 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);
+}
+
 /*
  * 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 0bbae825bc022..b3dca834f48ca 100644
--- 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 9193d6133e5d6..98488b20b594e 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);
 }