From: Zhang Yi yi.zhang@huawei.com
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@huaw...
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Add a new helper rem_u64() to only get the remainder of unsigned 64bit divide with 32bit divisor.
Signed-off-by: Zhang Yi yi.zhang@huawei.com Signed-off-by: Long Li leo.lilong@huawei.com --- include/linux/math64.h | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+)
diff --git a/include/linux/math64.h b/include/linux/math64.h index 66deb1fdc2ef..b5c4d1df08e5 100644 --- a/include/linux/math64.h +++ b/include/linux/math64.h @@ -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) {