From 2fe1e67e6987b6f05329740da79c8150a2205b0d Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Fri, 26 May 2023 08:47:40 -0700 Subject: x86/csum: Fix clang -Wuninitialized in csum_partial() Clang warns: arch/x86/lib/csum-partial_64.c:74:20: error: variable 'result' is uninitialized when used here [-Werror,-Wuninitialized] return csum_tail(result, temp64, odd); ^~~~~~ arch/x86/lib/csum-partial_64.c:48:22: note: initialize the variable 'result' to silence this warning unsigned odd, result; ^ = 0 1 error generated. The only initialization and uses of result in csum_partial() were moved into csum_tail() but result is still being passed by value to csum_tail() (clang's -Wuninitialized does not do interprocedural analysis to realize that result is always assigned in csum_tail() however). Sink the declaration of result into csum_tail() to clear up the warning. Closes: https://lore.kernel.org/202305262039.3HUYjWJk-lkp@intel.com/ Fixes: 688eb8191b47 ("x86/csum: Improve performance of `csum_partial`") Reported-by: kernel test robot Signed-off-by: Nathan Chancellor Signed-off-by: Dave Hansen Link: https://lore.kernel.org/all/20230526-csum_partial-wuninitialized-v1-1-ebc0108dcec1%40kernel.org --- arch/x86/lib/csum-partial_64.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'arch/x86/lib') diff --git a/arch/x86/lib/csum-partial_64.c b/arch/x86/lib/csum-partial_64.c index fe5861951b15..cea25ca8b8cf 100644 --- a/arch/x86/lib/csum-partial_64.c +++ b/arch/x86/lib/csum-partial_64.c @@ -21,8 +21,10 @@ static inline unsigned short from32to16(unsigned a) return b; } -static inline __wsum csum_tail(unsigned int result, u64 temp64, int odd) +static inline __wsum csum_tail(u64 temp64, int odd) { + unsigned int result; + result = add32_with_carry(temp64 >> 32, temp64 & 0xffffffff); if (unlikely(odd)) { result = from32to16(result); @@ -45,7 +47,7 @@ static inline __wsum csum_tail(unsigned int result, u64 temp64, int odd) __wsum csum_partial(const void *buff, int len, __wsum sum) { u64 temp64 = (__force u64)sum; - unsigned odd, result; + unsigned odd; odd = 1 & (unsigned long) buff; if (unlikely(odd)) { @@ -71,7 +73,7 @@ __wsum csum_partial(const void *buff, int len, __wsum sum) "adcq $0,%[res]" : [res] "+r"(temp64) : [src] "r"(buff), "m"(*(const char(*)[40])buff)); - return csum_tail(result, temp64, odd); + return csum_tail(temp64, odd); } if (unlikely(len >= 64)) { /* @@ -141,7 +143,7 @@ __wsum csum_partial(const void *buff, int len, __wsum sum) : [res] "+r"(temp64) : [trail] "r"(trail)); } - return csum_tail(result, temp64, odd); + return csum_tail(temp64, odd); } EXPORT_SYMBOL(csum_partial); -- cgit v1.2.3