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userfaultfd/selftests: create alias mappings in the shmem test

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Previously, we just allocated two shm areas: area_src and area_dst.  With
this commit, change this so we also allocate area_src_alias, and
area_dst_alias.

area_*_alias and area_* (respectively) point to the same underlying
physical pages, but are different VMAs.  In a future commit in this
series, we'll leverage this setup to exercise minor fault handling support
for shmem, just like we do in the hugetlb_shared test.

Link: https://lkml.kernel.org/r/20210503180737.2487560-9-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 18:49:38 -07:00 committed by Linus Torvalds
parent fa2c2b5818
commit 5bb23edb18
1 changed files with 19 additions and 3 deletions
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22
tools/testing/selftests/vm/userfaultfd.c
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@ -278,13 +278,29 @@ 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;
void *area_alias = NULL;
bool is_src = alloc_area == (void **)&area_src;
unsigned long offset = is_src ? 0 : nr_pages * page_size;
*alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
MAP_SHARED, shm_fd, offset);
if (*alloc_area == MAP_FAILED)
err("mmap of memfd failed");
area_alias = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
MAP_SHARED, shm_fd, offset);
if (area_alias == MAP_FAILED)
err("mmap of memfd alias failed");
if (is_src)
area_src_alias = area_alias;
else
area_dst_alias = area_alias;
}
static void shmem_alias_mapping(__u64 *start, size_t len, unsigned long offset)
{
*start = (unsigned long)area_dst_alias + offset;
}
struct uffd_test_ops {
@ -314,7 +330,7 @@ static struct uffd_test_ops shmem_uffd_test_ops = {
.expected_ioctls = SHMEM_EXPECTED_IOCTLS,
.allocate_area = shmem_allocate_area,
.release_pages = shmem_release_pages,
.alias_mapping = noop_alias_mapping,
.alias_mapping = shmem_alias_mapping,
};
static struct uffd_test_ops hugetlb_uffd_test_ops = {