Commit fa2c2b58 authored by Axel Rasmussen's avatar Axel Rasmussen Committed by Linus Torvalds
Browse files

userfaultfd/selftests: use memfd_create for shmem test type 

This is a preparatory commit.  In the future, we want to be able to setup
alias mappings for area_src and area_dst in the shmem test, like we do in
the hugetlb_shared test.  With a VMA obtained via mmap(MAP_ANONYMOUS |
MAP_SHARED), it isn't clear how to do this.

So, mmap() with an fd, so we can create alias mappings.  Use memfd_create
instead of actually passing in a tmpfs path like hugetlb does, since it's
more convenient / simpler to run, and works just as well.

Future commits will:

1. Setup the alias mappings.
2. Extend our tests to actually take advantage of this, to test new
   userfaultfd behavior being introduced in this series.

Also, a small fix in the area we're changing: when the hugetlb setup fails
in main(), pass in the right argv[] so we actually print out the hugetlb
file path.

Link: https://lkml.kernel.org/r/20210503180737.2487560-8-axelrasmussen@google.com


Signed-off-by: default avatarAxel Rasmussen <axelrasmussen@google.com>
Reviewed-by: default avatarPeter Xu <peterx@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Oliver Upton <oupton@google.com>
Cc: Shaohua Li <shli@fb.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Wang Qing <wangqing@vivo.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7d64ae3a

tools/testing/selftests/vm/userfaultfd.c

+15 −1
Original line number Diff line number Diff line
@@ -85,6 +85,7 @@ static bool test_uffdio_wp = false; 
static bool test_uffdio_minor = false;



static bool map_shared;

static int shm_fd;

static int huge_fd;

static char *huge_fd_off0;

static unsigned long long *count_verify;
@@ -277,8 +278,11 @@ static void shmem_release_pages(char *rel_area) 


static void shmem_allocate_area(void **alloc_area)

{

	unsigned long offset =

		alloc_area == (void **)&area_src ? 0 : nr_pages * page_size;



	*alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,

			   MAP_ANONYMOUS | MAP_SHARED, -1, 0);

			   MAP_SHARED, shm_fd, offset);

	if (*alloc_area == MAP_FAILED)

		err("mmap of memfd failed");

}
@@ -1602,6 +1606,16 @@ int main(int argc, char **argv) 
			err("Open of %s failed", argv[4]);

		if (ftruncate(huge_fd, 0))

			err("ftruncate %s to size 0 failed", argv[4]);

	} else if (test_type == TEST_SHMEM) {

		shm_fd = memfd_create(argv[0], 0);

		if (shm_fd < 0)

			err("memfd_create");

		if (ftruncate(shm_fd, nr_pages * page_size * 2))

			err("ftruncate");

		if (fallocate(shm_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);