[PATCH -next] selftests/mm: mseal, self_elf: Fix warning comparing pointer to 0

[PATCH -next] selftests/mm: mseal, self_elf: Fix warning comparing pointer to 0

[Jiapeng Chong]

Avoid pointer type value compared with 0 to make code clear.

./tools/testing/selftests/mm/mseal_test.c:486:27-28: WARNING comparing pointer to 0.
./tools/testing/selftests/mm/mseal_test.c:1399:29-30: WARNING comparing pointer to 0.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=9552
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
---
 tools/testing/selftests/mm/mseal_test.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/mm/mseal_test.c b/tools/testing/selftests/mm/mseal_test.c
index a818f010de47..50a5b9b9399e 100644
--- a/tools/testing/selftests/mm/mseal_test.c
+++ b/tools/testing/selftests/mm/mseal_test.c
@@ -481,9 +481,8 @@ static void test_seal_zero_address(void)
 	int prot;
 
 	/* use mmap to change protection. */
-	ptr = sys_mmap(0, size, PROT_NONE,
-			MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0);
-	FAIL_TEST_IF_FALSE(ptr == 0);
+	ptr = sys_mmap(0, size, PROT_NONE, MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0);
+	FAIL_TEST_IF_FALSE(!ptr);
 
 	size = get_vma_size(ptr, &prot);
 	FAIL_TEST_IF_FALSE(size == 4 * page_size);
@@ -1390,13 +1389,12 @@ static void test_seal_mremap_move_fixed_zero(bool seal)
 	/*
 	 * MREMAP_FIXED can move the mapping to zero address
 	 */
-	ret2 = mremap(ptr, size, 2 * page_size, MREMAP_MAYMOVE | MREMAP_FIXED,
-			0);
+	ret2 = mremap(ptr, size, 2 * page_size, MREMAP_MAYMOVE | MREMAP_FIXED, 0);
 	if (seal) {
 		FAIL_TEST_IF_FALSE(ret2 == MAP_FAILED);
 		FAIL_TEST_IF_FALSE(errno == EPERM);
 	} else {
-		FAIL_TEST_IF_FALSE(ret2 == 0);
+		FAIL_TEST_IF_FALSE(!ret2);
 
 	}
 
-- 
2.32.0.3.g01195cf9f

Re: [PATCH -next] selftests/mm: mseal, self_elf: Fix warning comparing pointer to 0

[Andrew Morton]

On Thu, 18 Jul 2024 11:10:39 +0800 Jiapeng Chong <jiapeng.chong@linux.alibaba.com> wrote:

> Avoid pointer type value compared with 0 to make code clear.
> 
> ./tools/testing/selftests/mm/mseal_test.c:486:27-28: WARNING comparing pointer to 0.
> ./tools/testing/selftests/mm/mseal_test.c:1399:29-30: WARNING comparing pointer to 0.
> 
> ...
>
> --- a/tools/testing/selftests/mm/mseal_test.c
> +++ b/tools/testing/selftests/mm/mseal_test.c
> @@ -481,9 +481,8 @@ static void test_seal_zero_address(void)
>  	int prot;
>  
>  	/* use mmap to change protection. */
> -	ptr = sys_mmap(0, size, PROT_NONE,
> -			MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0);
> -	FAIL_TEST_IF_FALSE(ptr == 0);
> +	ptr = sys_mmap(0, size, PROT_NONE, MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0);
> +	FAIL_TEST_IF_FALSE(!ptr);
> @@ -1390,13 +1389,12 @@ static void test_seal_mremap_move_fixed_zero(bool seal)
>  	/*
>  	 * MREMAP_FIXED can move the mapping to zero address
>  	 */
> -	ret2 = mremap(ptr, size, 2 * page_size, MREMAP_MAYMOVE | MREMAP_FIXED,
> -			0);
> +	ret2 = mremap(ptr, size, 2 * page_size, MREMAP_MAYMOVE | MREMAP_FIXED, 0);

The author of this code chose to make it tractable in an 80-column
display.  It's best not to change that, without explanation.