linux-kernel - [PATCH v5 08/18] timers: Create helper function to forward timer base clk

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Date:   Wed,  1 Mar 2023 15:17:34 +0100
From:   Anna-Maria Behnsen <anna-maria@...utronix.de>
To:     linux-kernel@...r.kernel.org
Cc:     Peter Zijlstra <peterz@...radead.org>,
        John Stultz <jstultz@...gle.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Eric Dumazet <edumazet@...gle.com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Arjan van de Ven <arjan@...radead.org>,
        "Paul E . McKenney" <paulmck@...nel.org>,
        Frederic Weisbecker <fweisbec@...il.com>,
        Rik van Riel <riel@...riel.com>,
        Anna-Maria Behnsen <anna-maria@...utronix.de>
Subject: [PATCH v5 08/18] timers: Create helper function to forward timer base clk

The logic for forwarding timer base clock is splitted into a separte
function to make it accessible for other call sites.

No functional change.

Signed-off-by: Anna-Maria Behnsen <anna-maria@...utronix.de>
---
v5: New patch to simplify next patch
---
 kernel/time/timer.c | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index d3e1776b505b..1629ccf24dd0 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1921,6 +1921,21 @@ static unsigned long next_timer_interrupt(struct timer_base *base)
 	return base->next_expiry;
 }
 
+/*
+ * Forward base clock is done only when @basej is past base->clk, otherwise
+ * base-clk might be rewind.
+ */
+static void forward_base_clk(struct timer_base *base, unsigned long nextevt,
+			     unsigned long basej)
+{
+	if (time_after(basej, base->clk)) {
+		if (time_after(nextevt, basej))
+			base->clk = basej;
+		else if (time_after(nextevt, base->clk))
+			base->clk = nextevt;
+	}
+}
+
 /**
  * get_next_timer_interrupt - return the time (clock mono) of the next timer
  * @basej:	base time jiffies
@@ -1952,15 +1967,9 @@ u64 get_next_timer_interrupt(unsigned long basej, u64 basem)
 
 	/*
 	 * We have a fresh next event. Check whether we can forward the
-	 * base. We can only do that when @basej is past base->clk
-	 * otherwise we might rewind base->clk.
+	 * base.
 	 */
-	if (time_after(basej, base->clk)) {
-		if (time_after(nextevt, basej))
-			base->clk = basej;
-		else if (time_after(nextevt, base->clk))
-			base->clk = nextevt;
-	}
+	forward_base_clk(base, nextevt, basej);
 
 	/*
 	 * Base is idle if the next event is more than a tick away. Also
-- 
2.30.2