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

Kuan-Wei Chiu
2025-02-23T16:43:23Z

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@gmail.com>
Signed-off-by: Yu-Chun Lin <eleanor15x@gmail.com>
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.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