Commit e058a3ad authored by Zhang Yi's avatar Zhang Yi Committed by Long Li
Browse files

math64: add rem_u64() to just return the remainder 

maillist inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I9VTE3
CVE: NA

Reference: https://lore.kernel.org/linux-fsdevel/20240529095206.2568162-1-yi.zhang@huaweicloud.com/



--------------------------------

Add a new helper rem_u64() to only get the remainder of unsigned 64bit
divide with 32bit divisor.

Fixes: fabcdd2d ("fs: xfs: Introduce FORCEALIGN inode flag")
Signed-off-by: default avatarZhang Yi <yi.zhang@huawei.com>
Signed-off-by: default avatarLong Li <leo.lilong@huawei.com>
parent b4141d36

include/linux/math64.h

+24 −0
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 
#define _LINUX_MATH64_H



#include <linux/types.h>

#include <linux/log2.h>

#include <vdso/math64.h>

#include <asm/div64.h>
@@ -11,6 +12,20 @@ 
#define div64_long(x, y) div64_s64((x), (y))

#define div64_ul(x, y)   div64_u64((x), (y))



/**

 * rem_u64 - remainder of unsigned 64bit divide with 32bit divisor

 * @dividend: unsigned 64bit dividend

 * @divisor: unsigned 32bit divisor

 *

 * Return: dividend % divisor

 */

static inline u32 rem_u64(u64 dividend, u32 divisor)

{

	if (is_power_of_2(divisor))

		return dividend & (divisor - 1);

	return dividend % divisor;

}



/**

 * div_u64_rem - unsigned 64bit divide with 32bit divisor with remainder

 * @dividend: unsigned 64bit dividend
@@ -85,6 +100,15 @@ static inline s64 div64_s64(s64 dividend, s64 divisor) 
#define div64_long(x, y) div_s64((x), (y))

#define div64_ul(x, y)   div_u64((x), (y))



#ifndef rem_u64

static inline u32 rem_u64(u64 dividend, u32 divisor)

{

	if (is_power_of_2(divisor))

		return dividend & (divisor - 1);

	return do_div(dividend, divisor);

}

#endif



#ifndef div_u64_rem

static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)

{