linux-kernel - [PATCH v2] time: Use div64_ul() instead of do

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Date: Mon, 26 Feb 2024 10:03:06 +0100
From: Thorsten Blum <thorsten.blum@...lux.com>
To: thorsten.blum@...lux.com
Cc: anna-maria@...utronix.de,
	frederic@...nel.org,
	jstultz@...gle.com,
	liaochang1@...wei.com,
	linux-kernel@...r.kernel.org,
	peterz@...radead.org,
	tglx@...utronix.de
Subject: [PATCH v2] time: Use div64_ul() instead of do_div()

Fixes Coccinelle/coccicheck warning reported by do_div.cocci.

Compared to do_div(), div64_ul() does not implicitly cast the divisor and
does not unnecessarily calculate the remainder.

Signed-off-by: Thorsten Blum <thorsten.blum@...lux.com>
---
Changes in v2:
- s/div64_long/div64_ul/ as suggested by Chang Liao
---
 kernel/time/jiffies.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/time/jiffies.c b/kernel/time/jiffies.c
index bc4db9e5ab70..fccee15e94d5 100644
--- a/kernel/time/jiffies.c
+++ b/kernel/time/jiffies.c
@@ -91,7 +91,7 @@ int register_refined_jiffies(long cycles_per_second)
 	/* shift_hz stores hz<<8 for extra accuracy */
 	shift_hz = (u64)cycles_per_second << 8;
 	shift_hz += cycles_per_tick/2;
-	do_div(shift_hz, cycles_per_tick);
+	shift_hz = div64_ul(shift_hz, cycles_per_tick);
 	/* Calculate nsec_per_tick using shift_hz */
 	nsec_per_tick = (u64)NSEC_PER_SEC << 8;
 	nsec_per_tick += (u32)shift_hz/2;
-- 
2.43.2