Re: [PATCH net] kunit: Fix again checksum tests on big endian CPUs

[Christophe Leroy]

Le 23/02/2024 à 18:57, Charlie Jenkins a écrit :
> On Fri, Feb 23, 2024 at 11:41:52AM +0100, Christophe Leroy wrote:
>> Commit b38460bc463c ("kunit: Fix checksum tests on big endian CPUs")
>> fixed endianness issues with kunit checksum tests, but then
>> commit 6f4c45cbcb00 ("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@xxxxxxxxxxx>
>> Fixes: 6f4c45cbcb00 ("kunit: Add tests for csum_ipv6_magic and ip_fast_csum")
>> Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
>> ---
>>   lib/checksum_kunit.c | 17 +++++++++--------
>>   1 file changed, 9 insertions(+), 8 deletions(-)
>>
>> diff --git a/lib/checksum_kunit.c b/lib/checksum_kunit.c
>> index 225bb7701460..bf70850035c7 100644
>> --- a/lib/checksum_kunit.c
>> +++ b/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 */
>> -- 
>> 2.43.0
>>
> 
> There is no need to duplicate efforts here. This has already been
> resolved by
> https://lore.kernel.org/lkml/20240221-fix_sparse_errors_checksum_tests-v9-2-bff4d73ab9d1@xxxxxxxxxxxx/.
> 

The idea here is to provide a fix which is similar to the one done 
previously and that uses the same approach and reuses the same helpers.

This is to keep the code homogeneous.

Christophe