linux-kernel - [tip: timers/core] timekeeping: Simplify code in timekeeping

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <172987928774.1442.15542081714807205566.tip-bot2@tip-bot2>
Date: Fri, 25 Oct 2024 18:01:27 -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>,
 John Stultz <jstultz@...gle.com>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject:
 [tip: timers/core] timekeeping: Simplify code in timekeeping_advance()

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

Commit-ID:     c2a329566a3d5a638061733f232c40379235931d
Gitweb:        https://git.kernel.org/tip/c2a329566a3d5a638061733f232c40379235931d
Author:        Thomas Gleixner <tglx@...utronix.de>
AuthorDate:    Wed, 09 Oct 2024 10:28:58 +02:00
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Fri, 25 Oct 2024 19:49:13 +02:00

timekeeping: Simplify code in timekeeping_advance()

timekeeping_advance() takes the timekeeper_lock and releases it before
returning. When an early return is required, goto statements are used to
make sure the lock is realeased properly. When the code was written the
locking guard() was not yet available.

Use the guard() to simplify the code and while at it cleanup ordering of
function variables. No functional change.

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>
Acked-by: John Stultz <jstultz@...gle.com>
Link: https://lore.kernel.org/all/20241009-devel-anna-maria-b4-timers-ptp-timekeeping-v2-5-554456a44a15@linutronix.de

---
 kernel/time/timekeeping.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index a9550f6..cfb718d 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -2307,23 +2307,22 @@ static bool timekeeping_advance(enum timekeeping_adv_mode mode)
 {
 	struct timekeeper *real_tk = &tk_core.timekeeper;
 	struct timekeeper *tk = &shadow_timekeeper;
-	u64 offset;
-	int shift = 0, maxshift;
 	unsigned int clock_set = 0;
-	unsigned long flags;
+	int shift = 0, maxshift;
+	u64 offset;
 
-	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	guard(raw_spinlock_irqsave)(&timekeeper_lock);
 
 	/* Make sure we're fully resumed: */
 	if (unlikely(timekeeping_suspended))
-		goto out;
+		return false;
 
 	offset = clocksource_delta(tk_clock_read(&tk->tkr_mono),
 				   tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
 
 	/* Check if there's really nothing to do */
 	if (offset < real_tk->cycle_interval && mode == TK_ADV_TICK)
-		goto out;
+		return false;
 
 	/* Do some additional sanity checking */
 	timekeeping_check_update(tk, offset);
@@ -2342,8 +2341,7 @@ static bool timekeeping_advance(enum timekeeping_adv_mode mode)
 	maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1;
 	shift = min(shift, maxshift);
 	while (offset >= tk->cycle_interval) {
-		offset = logarithmic_accumulation(tk, offset, shift,
-							&clock_set);
+		offset = logarithmic_accumulation(tk, offset, shift, &clock_set);
 		if (offset < tk->cycle_interval<<shift)
 			shift--;
 	}
@@ -2372,8 +2370,6 @@ static bool timekeeping_advance(enum timekeeping_adv_mode mode)
 	memcpy(real_tk, tk, sizeof(*tk));
 	/* The memcpy must come last. Do not put anything here! */
 	write_seqcount_end(&tk_core.seq);
-out:
-	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
 
 	return !!clock_set;
 }