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userfaultfd/selftests: use memfd_create for shmem test type

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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: Axel Rasmussen <axelrasmussen@google.com>
Reviewed-by: Peter 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Axel Rasmussen 2021-06-30 18:49:34 -07:00 committed by Linus Torvalds
parent 7d64ae3ab6
commit fa2c2b5818
1 changed files with 15 additions and 1 deletions
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16
tools/testing/selftests/vm/userfaultfd.c
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@ -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);