2023-04-12 07:40:21

by Deming Wang

Subject: [PATCH] selftests/mm: Replace obsolete memalign() with posix_memalign()

memalign() is obsolete according to its manpage.

Replace memalign() with posix_memalign() and remove malloc.h include
that was there for memalign().

As a pointer is passed into posix_memalign(), initialize *p to NULL
to silence a warning about the function's return value being used as
uninitialized (which is not valid anyway because the error is properly
checked before p is returned).

Signed-off-by: Deming Wang <[email protected]>
---
tools/testing/selftests/mm/soft-dirty.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/mm/soft-dirty.c b/tools/testing/selftests/mm/soft-dirty.c
index 21d8830c5f24..4bb7421141a2 100644
--- a/tools/testing/selftests/mm/soft-dirty.c
+++ b/tools/testing/selftests/mm/soft-dirty.c
@@ -80,8 +80,8 @@ static void test_hugepage(int pagemap_fd, int pagesize)
int i, ret;
size_t hpage_len = read_pmd_pagesize();

- map = memalign(hpage_len, hpage_len);
- if (!map)
+ ret = posix_memalign((void *)(&map), hpage_len, hpage_len);
+ if (ret < 0)
ksft_exit_fail_msg("memalign failed\n");

ret = madvise(map, hpage_len, MADV_HUGEPAGE);
--
2.27.0

2023-04-12 08:30:59

by David Hildenbrand

Subject: Re: [PATCH] selftests/mm: Replace obsolete memalign() with posix_memalign()

On 12.04.23 09:27, Deming Wang wrote:
> memalign() is obsolete according to its manpage.
>
> Replace memalign() with posix_memalign() and remove malloc.h include
> that was there for memalign().
>
> As a pointer is passed into posix_memalign(), initialize *p to NULL
> to silence a warning about the function's return value being used as
> uninitialized (which is not valid anyway because the error is properly
> checked before p is returned).

I don't follow how that comment here applies to the patch. What is p?
Where is it initialized to NULL?

>
> Signed-off-by: Deming Wang <[email protected]>
> ---
> tools/testing/selftests/mm/soft-dirty.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/mm/soft-dirty.c b/tools/testing/selftests/mm/soft-dirty.c
> index 21d8830c5f24..4bb7421141a2 100644
> --- a/tools/testing/selftests/mm/soft-dirty.c
> +++ b/tools/testing/selftests/mm/soft-dirty.c
> @@ -80,8 +80,8 @@ static void test_hugepage(int pagemap_fd, int pagesize)
> int i, ret;
> size_t hpage_len = read_pmd_pagesize();
>
> - map = memalign(hpage_len, hpage_len);
> - if (!map)
> + ret = posix_memalign((void *)(&map), hpage_len, hpage_len);

posix_memalign expects an "void **memptr", casting to "void *" looks
weird. Further, you can drop the parentheses around &map.

ret = posix_memalign((void **)&map, hpage_len, hpage_len);


> + if (ret < 0)
> ksft_exit_fail_msg("memalign failed\n");

Better adjust the comment to "posix_memalign() failed\n"

--
Thanks,

David / dhildenb