linux-kernel - [PATCH] hpet: Optimize local variable data type in hpet

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Message-ID: <20240710215238.799239-2-thorsten.blum@toblux.com>
Date: Wed, 10 Jul 2024 23:52:39 +0200
From: Thorsten Blum <thorsten.blum@...lux.com>
To: clemens@...isch.de,
	arnd@...db.de,
	gregkh@...uxfoundation.org
Cc: linux-kernel@...r.kernel.org,
	Thorsten Blum <thorsten.blum@...lux.com>
Subject: [PATCH] hpet: Optimize local variable data type in hpet_alloc()

The local variable period uses at most 32 bits and can be a u32 instead
of unsigned long. The upper 32 bits are all 0 after masking and right
shifting cap by HPET_COUNTER_CLK_PERIOD_SHIFT and can be discarded.

Since do_div() casts the divisor to u32 anyway, changing the data type
of period to u32 also removes the following Coccinelle/coccicheck
warning reported by do_div.cocci:

  WARNING: do_div() does a 64-by-32 division, please consider using div64_ul instead

Signed-off-by: Thorsten Blum <thorsten.blum@...lux.com>
---
 drivers/char/hpet.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c
index d51fc8321d41..bd68afa22cff 100644
--- a/drivers/char/hpet.c
+++ b/drivers/char/hpet.c
@@ -784,7 +784,7 @@ int hpet_alloc(struct hpet_data *hdp)
 	struct hpets *hpetp;
 	struct hpet __iomem *hpet;
 	static struct hpets *last;
-	unsigned long period;
+	u32 period;
 	unsigned long long temp;
 	u32 remainder;
 
-- 
2.45.2