linux-kernel - [tip: timers/core] timekeeping: Don't stop time readers across hard

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Message-ID: <172987928985.1442.4888093989004626478.tip-bot2@tip-bot2>
Date: Fri, 25 Oct 2024 18:01:29 -0000
From: "tip-bot2 for Thomas Gleixner" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Thomas Gleixner <tglx@...utronix.de>,
 "Anna-Maria Behnsen" <anna-maria@...utronix.de>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: timers/core] timekeeping: Don't stop time readers across
 hard_pps() update

The following commit has been merged into the timers/core branch of tip:

Commit-ID:     886150fb4f19505b8f9d26201d7671b25c233a9f
Gitweb:        https://git.kernel.org/tip/886150fb4f19505b8f9d26201d7671b25c233a9f
Author:        Thomas Gleixner <tglx@...utronix.de>
AuthorDate:    Wed, 09 Oct 2024 10:28:55 +02:00
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Fri, 25 Oct 2024 19:49:13 +02:00

timekeeping: Don't stop time readers across hard_pps() update

hard_pps() update does not modify anything which might be required by time
readers so forcing readers out of the way during the update is a pointless
exercise.

The interaction with adjtimex() and timekeeper updates which call into the
NTP code is properly serialized by timekeeper_lock.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Anna-Maria Behnsen <anna-maria@...utronix.de>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Link: https://lore.kernel.org/all/20241009-devel-anna-maria-b4-timers-ptp-timekeeping-v2-2-554456a44a15@linutronix.de

---
 kernel/time/timekeeping.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 2bc3542..ff98a0b 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -2746,11 +2746,7 @@ void hardpps(const struct timespec64 *phase_ts, const struct timespec64 *raw_ts)
 	unsigned long flags;
 
 	raw_spin_lock_irqsave(&timekeeper_lock, flags);
-	write_seqcount_begin(&tk_core.seq);
-
 	__hardpps(phase_ts, raw_ts);
-
-	write_seqcount_end(&tk_core.seq);
 	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
 }
 EXPORT_SYMBOL(hardpps);