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_shift(__wsum sum, int offset)
+{
+	/* rotate sum to align it with a 16b boundary */
+	if (offset & 1)
+		return (__force __wsum)ror32((__force u32)sum, 8);
+	return sum;
+}
+
 static inline __wsum
 csum_block_add(__wsum csum, __wsum csum2, int offset)
 {
-	u32 sum = (__force u32)csum2;
-
-	/* rotate sum to align it with a 16b boundary */
-	if (offset & 1)
-		sum = ror32(sum, 8);
-
-	return csum_add(csum, (__force __wsum)sum);
+	return csum_add(csum, csum_shift(csum2, offset));
 }
 
 static inline __wsum
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 362e8b5a5dc5..93ae0c2c8d66 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1781,8 +1781,8 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate,
 	if (unlikely(iov_iter_is_pipe(i)))
 		return csum_and_copy_to_pipe_iter(addr, bytes, _csstate, i);
 
-	sum = csstate->csum;
-	off = csstate->off;
+	sum = csum_shift(csstate->csum, csstate->off);
+	off = 0;
 	if (unlikely(iov_iter_is_discard(i))) {
 		WARN_ON(1);	/* for now */
 		return 0;
@@ -1817,8 +1817,8 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate,
 		off += v.bv_len;
 	})
 	)
-	csstate->csum = sum;
-	csstate->off = off;
+	csstate->csum = csum_shift(sum, csstate->off);
+	csstate->off += bytes;
 	return bytes;
 }
 EXPORT_SYMBOL(csum_and_copy_to_iter);