Re: [PATCH 17/29] selftests/mm: Drop global mem_fd in uffd tests

[Mike Rapoport <rppt@linux.ibm.com>]

On Thu, Mar 30, 2023 at 12:08:06PM -0400, Peter Xu wrote:
> Drop it by creating the memfd dynamically in the tests.
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>

Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>

> ---
>  tools/testing/selftests/mm/uffd-common.c | 28 +++++++++++++++++++++++-
>  tools/testing/selftests/mm/uffd-common.h |  2 +-
>  tools/testing/selftests/mm/uffd-stress.c | 15 -------------
>  3 files changed, 28 insertions(+), 17 deletions(-)
> 
> diff --git a/tools/testing/selftests/mm/uffd-common.c b/tools/testing/selftests/mm/uffd-common.c
> index 3a9b5c1aca9d..a2b6e4957d0f 100644
> --- a/tools/testing/selftests/mm/uffd-common.c
> +++ b/tools/testing/selftests/mm/uffd-common.c
> @@ -12,12 +12,32 @@
>  volatile bool test_uffdio_copy_eexist = true;
>  unsigned long nr_cpus, nr_pages, nr_pages_per_cpu, page_size, hpage_size;
>  char *area_src, *area_src_alias, *area_dst, *area_dst_alias, *area_remap;
> -int mem_fd, uffd = -1, uffd_flags, finished, *pipefd, test_type;
> +int uffd = -1, uffd_flags, finished, *pipefd, test_type;
>  bool map_shared, test_collapse, test_dev_userfaultfd;
>  bool test_uffdio_wp = true, test_uffdio_minor = false;
>  unsigned long long *count_verify;
>  uffd_test_ops_t *uffd_test_ops;
> 
> +static int uffd_mem_fd_create(off_t mem_size, bool hugetlb)
> +{
> +	unsigned int memfd_flags = 0;
> +	int mem_fd;
> +
> +	if (hugetlb)
> +		memfd_flags = MFD_HUGETLB;
> +	mem_fd = memfd_create("uffd-test", memfd_flags);
> +	if (mem_fd < 0)
> +		err("memfd_create");
> +	if (ftruncate(mem_fd, mem_size))
> +		err("ftruncate");
> +	if (fallocate(mem_fd,
> +		      FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, 0,
> +		      mem_size))
> +		err("fallocate");
> +
> +	return mem_fd;
> +}
> +
>  static void anon_release_pages(char *rel_area)
>  {
>  	if (madvise(rel_area, nr_pages * page_size, MADV_DONTNEED))
> @@ -51,6 +71,7 @@ static void hugetlb_allocate_area(void **alloc_area, bool is_src)
>  	off_t offset = is_src ? 0 : size;
>  	void *area_alias = NULL;
>  	char **alloc_area_alias;
> +	int mem_fd = uffd_mem_fd_create(size * 2, true);
> 
>  	*alloc_area = mmap(NULL, size, PROT_READ | PROT_WRITE,
>  			   (map_shared ? MAP_SHARED : MAP_PRIVATE) |
> @@ -73,6 +94,8 @@ static void hugetlb_allocate_area(void **alloc_area, bool is_src)
>  	}
>  	if (area_alias)
>  		*alloc_area_alias = area_alias;
> +
> +	close(mem_fd);
>  }
> 
>  static void hugetlb_alias_mapping(__u64 *start, size_t len, unsigned long offset)
> @@ -95,6 +118,7 @@ static void shmem_allocate_area(void **alloc_area, bool is_src)
>  	size_t bytes = nr_pages * page_size;
>  	unsigned long offset = is_src ? 0 : bytes;
>  	char *p = NULL, *p_alias = NULL;
> +	int mem_fd = uffd_mem_fd_create(bytes * 2, false);
> 
>  	if (test_collapse) {
>  		p = BASE_PMD_ADDR;
> @@ -124,6 +148,8 @@ static void shmem_allocate_area(void **alloc_area, bool is_src)
>  		area_src_alias = area_alias;
>  	else
>  		area_dst_alias = area_alias;
> +
> +	close(mem_fd);
>  }
> 
>  static void shmem_alias_mapping(__u64 *start, size_t len, unsigned long offset)
> diff --git a/tools/testing/selftests/mm/uffd-common.h b/tools/testing/selftests/mm/uffd-common.h
> index 11f770391bd9..0dfab7057295 100644
> --- a/tools/testing/selftests/mm/uffd-common.h
> +++ b/tools/testing/selftests/mm/uffd-common.h
> @@ -87,7 +87,7 @@ typedef struct uffd_test_ops uffd_test_ops_t;
> 
>  extern unsigned long nr_cpus, nr_pages, nr_pages_per_cpu, page_size, hpage_size;
>  extern char *area_src, *area_src_alias, *area_dst, *area_dst_alias, *area_remap;
> -extern int mem_fd, uffd, uffd_flags, finished, *pipefd, test_type;
> +extern int uffd, uffd_flags, finished, *pipefd, test_type;
>  extern bool map_shared, test_collapse, test_dev_userfaultfd;
>  extern bool test_uffdio_wp, test_uffdio_minor;
>  extern unsigned long long *count_verify;
> diff --git a/tools/testing/selftests/mm/uffd-stress.c b/tools/testing/selftests/mm/uffd-stress.c
> index e6d39a755082..4eca1a0276c2 100644
> --- a/tools/testing/selftests/mm/uffd-stress.c
> +++ b/tools/testing/selftests/mm/uffd-stress.c
> @@ -1090,21 +1090,6 @@ int main(int argc, char **argv)
>  	}
>  	nr_pages = nr_pages_per_cpu * nr_cpus;
> 
> -	if (test_type == TEST_SHMEM || test_type == TEST_HUGETLB) {
> -		unsigned int memfd_flags = 0;
> -
> -		if (test_type == TEST_HUGETLB)
> -			memfd_flags = MFD_HUGETLB;
> -		mem_fd = memfd_create(argv[0], memfd_flags);
> -		if (mem_fd < 0)
> -			err("memfd_create");
> -		if (ftruncate(mem_fd, nr_pages * page_size * 2))
> -			err("ftruncate");
> -		if (fallocate(mem_fd,
> -			      FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, 0,
> -			      nr_pages * page_size * 2))
> -			err("fallocate");
> -	}
>  	printf("nr_pages: %lu, nr_pages_per_cpu: %lu\n",
>  	       nr_pages, nr_pages_per_cpu);
>  	return userfaultfd_stress();
> -- 
> 2.39.1
> 

-- 
Sincerely yours,
Mike.