[PATCH 04/24] checksum: add csum_iov()

[Laurent Vivier <lvivier@redhat.com>]

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 checksum.c | 39 ++++++++++++++++++++++-----------------
 checksum.h |  1 +
 2 files changed, 23 insertions(+), 17 deletions(-)

diff --git a/checksum.c b/checksum.c
index c94980771c63..14b6057684d9 100644
--- a/checksum.c
+++ b/checksum.c
@@ -395,17 +395,8 @@ less_than_128_bytes:
 	return (uint32_t)sum64;
 }
 
-/**
- * csum() - Compute TCP/IP-style checksum
- * @buf:	Input buffer, must be aligned to 32-byte boundary
- * @len:	Input length
- * @init:	Initial 32-bit checksum, 0 for no pre-computed checksum
- *
- * Return: 16-bit folded, complemented checksum sum
- */
-/* NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) */
 __attribute__((optimize("-fno-strict-aliasing")))	/* See csum_16b() */
-uint16_t csum(const void *buf, size_t len, uint32_t init)
+uint32_t csum_unfolded(const void *buf, size_t len, uint32_t init)
 {
 	intptr_t align = ((intptr_t)buf + 0x1f) & ~(intptr_t)0x1f;
 	unsigned int pad = align - (intptr_t)buf;
@@ -419,24 +410,38 @@ uint16_t csum(const void *buf, size_t len, uint32_t init)
 	if (len > pad)
 		init = csum_avx2((void *)align, len - pad, init);
 
-	return (uint16_t)~csum_fold(init);
+	return init;
 }
-
 #else /* __AVX2__ */
 
+__attribute__((optimize("-fno-strict-aliasing")))	/* See csum_16b() */
+uint32_t csum_unfolded(const void *buf, size_t len, uint32_t init)
+{
+	return sum_16b(buf, len) + init;
+}
+#endif /* !__AVX2__ */
+
 /**
  * csum() - Compute TCP/IP-style checksum
- * @buf:	Input buffer
+ * @buf:	Input buffer, must be aligned to 32-byte boundary
  * @len:	Input length
- * @sum:	Initial 32-bit checksum, 0 for no pre-computed checksum
+ * @init:	Initial 32-bit checksum, 0 for no pre-computed checksum
  *
- * Return: 16-bit folded, complemented checksum
+ * Return: 16-bit folded, complemented checksum sum
  */
 /* NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) */
 __attribute__((optimize("-fno-strict-aliasing")))	/* See csum_16b() */
 uint16_t csum(const void *buf, size_t len, uint32_t init)
 {
-	return csum_unaligned(buf, len, init);
+	return (uint16_t)~csum_fold(csum_unfolded(buf, len, init));
 }
 
-#endif /* !__AVX2__ */
+uint16_t csum_iov(struct iovec *iov, unsigned int n, uint32_t init)
+{
+	unsigned int i;
+
+	for (i = 0; i < n;  i++)
+		init = csum_unfolded(iov[i].iov_base, iov[i].iov_len, init);
+
+	return (uint16_t)~csum_fold(init);
+}
diff --git a/checksum.h b/checksum.h
index 21c0310d3804..6a20297a5826 100644
--- a/checksum.h
+++ b/checksum.h
@@ -25,5 +25,6 @@ void csum_icmp6(struct icmp6hdr *icmp6hr,
 		const struct in6_addr *saddr, const struct in6_addr *daddr,
 		const void *payload, size_t len);
 uint16_t csum(const void *buf, size_t len, uint32_t init);
+uint16_t csum_iov(struct iovec *iov, unsigned int n, uint32_t init);
 
 #endif /* CHECKSUM_H */
-- 
@@ -25,5 +25,6 @@ void csum_icmp6(struct icmp6hdr *icmp6hr,
 		const struct in6_addr *saddr, const struct in6_addr *daddr,
 		const void *payload, size_t len);
 uint16_t csum(const void *buf, size_t len, uint32_t init);
+uint16_t csum_iov(struct iovec *iov, unsigned int n, uint32_t init);
 
 #endif /* CHECKSUM_H */
-- 
2.42.0