linux-kernel - [PATCH 03/17] x86: Replace open-coded parity calculation with parity8()

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Message-Id: <20250223164217.2139331-4-visitorckw@gmail.com>
Date: Mon, 24 Feb 2025 00:42:03 +0800
From: Kuan-Wei Chiu <visitorckw@...il.com>
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	Kuan-Wei Chiu <visitorckw@...il.com>,
	Yu-Chun Lin <eleanor15x@...il.com>
Subject: [PATCH 03/17] x86: Replace open-coded parity calculation with parity8()

Refactor parity calculations to use the standard parity8() helper. This
change eliminates redundant implementations and improves code
efficiency.

Co-developed-by: Yu-Chun Lin <eleanor15x@...il.com>
Signed-off-by: Yu-Chun Lin <eleanor15x@...il.com>
Signed-off-by: Kuan-Wei Chiu <visitorckw@...il.com>
---
 arch/x86/kernel/bootflag.c | 18 +++---------------
 1 file changed, 3 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kernel/bootflag.c b/arch/x86/kernel/bootflag.c
index 3fed7ae58b60..314ff0e84900 100644
--- a/arch/x86/kernel/bootflag.c
+++ b/arch/x86/kernel/bootflag.c
@@ -8,6 +8,7 @@
 #include <linux/string.h>
 #include <linux/spinlock.h>
 #include <linux/acpi.h>
+#include <linux/bitops.h>
 #include <asm/io.h>
 
 #include <linux/mc146818rtc.h>
@@ -20,26 +21,13 @@
 
 int sbf_port __initdata = -1;	/* set via acpi_boot_init() */
 
-static int __init parity(u8 v)
-{
-	int x = 0;
-	int i;
-
-	for (i = 0; i < 8; i++) {
-		x ^= (v & 1);
-		v >>= 1;
-	}
-
-	return x;
-}
-
 static void __init sbf_write(u8 v)
 {
 	unsigned long flags;
 
 	if (sbf_port != -1) {
 		v &= ~SBF_PARITY;
-		if (!parity(v))
+		if (!parity8(v))
 			v |= SBF_PARITY;
 
 		printk(KERN_INFO "Simple Boot Flag at 0x%x set to 0x%x\n",
@@ -70,7 +58,7 @@ static int __init sbf_value_valid(u8 v)
 {
 	if (v & SBF_RESERVED)		/* Reserved bits */
 		return 0;
-	if (!parity(v))
+	if (!parity8(v))
 		return 0;
 
 	return 1;
-- 
2.34.1