kunit: Fix again checksum tests on big endian CPUs

Commit b38460bc ("kunit: Fix checksum tests on big endian CPUs")
fixed endianness issues with kunit checksum tests, but then
commit 6f4c45cb ("kunit: Add tests for csum_ipv6_magic and
ip_fast_csum") introduced new issues on big endian CPUs. Those issues
are once again reflected by the warnings reported by sparse.

So, fix them with the same approach, perform proper conversion in
order to support both little and big endian CPUs. Once the conversions
are properly done and the right types used, the sparse warnings are
cleared as well.
Reported-by: Erhard Furtner <erhard_f@mailbox.org>
Fixes: 6f4c45cb ("kunit: Add tests for csum_ipv6_magic and ip_fast_csum")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Tested-by: Charlie Jenkins <charlie@rivosinc.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/73df3a9e95c2179119398ad1b4c84cdacbd8dfb6.1708684443.git.christophe.leroy@csgroup.euSigned-off-by: Jakub Kicinski <kuba@kernel.org>

lib/checksum_kunit.c

@@ -215,7 +215,7 @@ static const u32 init_sums_no_overflow[] = {
 	0xffff0000, 0xfffffffb,
 };
 
-static const __sum16 expected_csum_ipv6_magic[] = {
+static const u16 expected_csum_ipv6_magic[] = {
 	0x18d4, 0x3085, 0x2e4b, 0xd9f4, 0xbdc8, 0x78f,	0x1034, 0x8422, 0x6fc0,
 	0xd2f6, 0xbeb5, 0x9d3,	0x7e2a, 0x312e, 0x778e, 0xc1bb, 0x7cf2, 0x9d1e,
 	0xca21, 0xf3ff, 0x7569, 0xb02e, 0xca86, 0x7e76, 0x4539, 0x45e3, 0xf28d,
@@ -241,7 +241,7 @@ static const __sum16 expected_csum_ipv6_magic[] = {
 	0x3845, 0x1014
 };
 
-static const __sum16 expected_fast_csum[] = {
+static const u16 expected_fast_csum[] = {
 	0xda83, 0x45da, 0x4f46, 0x4e4f, 0x34e,	0xe902, 0xa5e9, 0x87a5, 0x7187,
 	0x5671, 0xf556, 0x6df5, 0x816d, 0x8f81, 0xbb8f, 0xfbba, 0x5afb, 0xbe5a,
 	0xedbe, 0xabee, 0x6aac, 0xe6b,	0xea0d, 0x67ea, 0x7e68, 0x8a7e, 0x6f8a,
@@ -577,7 +577,8 @@ static void test_csum_no_carry_inputs(struct kunit *test)
 
 static void test_ip_fast_csum(struct kunit *test)
 {
-	__sum16 csum_result, expected;
+	__sum16 csum_result;
+	u16 expected;
 
 	for (int len = IPv4_MIN_WORDS; len < IPv4_MAX_WORDS; len++) {
 		for (int index = 0; index < NUM_IP_FAST_CSUM_TESTS; index++) {
@@ -586,7 +587,7 @@ static void test_ip_fast_csum(struct kunit *test)
 				expected_fast_csum[(len - IPv4_MIN_WORDS) *
 						   NUM_IP_FAST_CSUM_TESTS +
 						   index];
-			CHECK_EQ(expected, csum_result);
+			CHECK_EQ(to_sum16(expected), csum_result);
 		}
 	}
 }
@@ -598,7 +599,7 @@ static void test_csum_ipv6_magic(struct kunit *test)
 	const struct in6_addr *daddr;
 	unsigned int len;
 	unsigned char proto;
-	unsigned int csum;
+	__wsum csum;
 
 	const int daddr_offset = sizeof(struct in6_addr);
 	const int len_offset = sizeof(struct in6_addr) + sizeof(struct in6_addr);
@@ -611,10 +612,10 @@ static void test_csum_ipv6_magic(struct kunit *test)
 		saddr = (const struct in6_addr *)(random_buf + i);
 		daddr = (const struct in6_addr *)(random_buf + i +
 						  daddr_offset);
-		len = *(unsigned int *)(random_buf + i + len_offset);
+		len = le32_to_cpu(*(__le32 *)(random_buf + i + len_offset));
 		proto = *(random_buf + i + proto_offset);
-		csum = *(unsigned int *)(random_buf + i + csum_offset);
-		CHECK_EQ(expected_csum_ipv6_magic[i],
+		csum = *(__wsum *)(random_buf + i + csum_offset);
+		CHECK_EQ(to_sum16(expected_csum_ipv6_magic[i]),
 			 csum_ipv6_magic(saddr, daddr, len, proto, csum));
 	}
 #endif /* !CONFIG_NET */