[PATCH v3 3/7] x86: avoid unneeded __div64_32 function definition

Arnd Bergmann
2023-08-03T08:29:37Z

The __div64_32() function is provided for 32-bit architectures that
don't have a custom do_div() implementation. x86_32 has one, and
does not use the header file that declares the function prototype,
so the definition causes a W=1 warning:

lib/math/div64.c:31:32: error: no previous prototype for '__div64_32' [-Werror=missing-prototypes]

Define an empty macro to prevent the function definition from getting
built, which avoids the warning and saves a little .text space.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
v3: improve code comment
---
arch/x86/include/asm/div64.h | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/arch/x86/include/asm/div64.h b/arch/x86/include/asm/div64.h
index b8f1dc0761e4b..9931e4c7d73f3 100644
--- a/arch/x86/include/asm/div64.h
+++ b/arch/x86/include/asm/div64.h
@@ -71,6 +71,12 @@ static inline u64 mul_u32_u32(u32 a, u32 b)
}
#define mul_u32_u32 mul_u32_u32

+/*
+ * __div64_32() is never called on x86, so prevent the
+ * generic definition from getting built.
+ */
+#define __div64_32
+
#else
# include <asm-generic/div64.h>

--
2.39.2