From 594e450b3f4435a9d663df3d48d7fa34e685cbd1 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sat, 5 Jun 2021 10:19:30 -0400 Subject: csum_and_copy_to_iter(): massage into form closer to csum_and_copy_from_iter() Namely, have off counted starting from 0 rather than from csstate->off. To compensate we need to shift the initial value (csstate->sum) (rotate by 8 bits, as usual for csum) and do the same after we are finished adding the pieces up. What we get out of that is a bit more redundancy in our variables - from is always equal to addr + off, which will be useful several commits down the road. Signed-off-by: Al Viro --- include/net/checksum.h | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) (limited to 'include/net') diff --git a/include/net/checksum.h b/include/net/checksum.h index 0d05b9e8690b..5b96d5bd6e54 100644 --- a/include/net/checksum.h +++ b/include/net/checksum.h @@ -80,16 +80,18 @@ static inline __sum16 csum16_sub(__sum16 csum, __be16 addend) return csum16_add(csum, ~addend); } -static inline __wsum -csum_block_add(__wsum csum, __wsum csum2, int offset) +static inline __wsum csum_shift(__wsum sum, int offset) { - u32 sum = (__force u32)csum2; - /* rotate sum to align it with a 16b boundary */ if (offset & 1) - sum = ror32(sum, 8); + return (__force __wsum)ror32((__force u32)sum, 8); + return sum; +} - return csum_add(csum, (__force __wsum)sum); +static inline __wsum +csum_block_add(__wsum csum, __wsum csum2, int offset) +{ + return csum_add(csum, csum_shift(csum2, offset)); } static inline __wsum -- cgit v1.2.3-73-gaa49b