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FROMGIT: 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/20210302000133.272579-4-axelrasmussen@google.com
Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Cannon Matthews <cannonmatthews@google.com>
Cc: David Rientjes <rientjes@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: Lokesh Gidra <lokeshgidra@google.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Oliver Upton <oupton@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shaohua Li <shli@fb.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Wang Qing <wangqing@vivo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

(cherry picked from commit 8bc5e62208bcb9427ea6eed94ff1b152598da6f8
https: //git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git akpm)
Link: https://lore.kernel.org/patchwork/patch/1388149/
Signed-off-by: Lokesh Gidra <lokeshgidra@google.com>
Bug: 160737021
Bug: 169683130
Change-Id: I1605dba2d5f0e35bfd57bd9110bb54e950faab19
This commit is contained in:
Axel Rasmussen
2021-03-18 17:01:52 +11:00
committed by Todd Kjos
parent 94f1573615
commit 4a460b5cba
1 changed files with 26 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

29
tools/testing/selftests/vm/userfaultfd.c
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@@ -289,8 +289,9 @@ static int 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);
@@ -299,12 +300,34 @@ static void shmem_allocate_area(void **alloc_area)
goto fail;
}
area_alias = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
MAP_SHARED, shm_fd, offset);
if (area_alias == MAP_FAILED) {
perror("mmap of memfd alias failed");
goto fail_munmap;
}
if (is_src)
area_src_alias = area_alias;
else
area_dst_alias = area_alias;
return;
fail_munmap:
if (munmap(*alloc_area, nr_pages * page_size) < 0) {
perror("munmap of memfd failed\n");
exit(1);
}
fail:
*alloc_area = NULL;
}
static void shmem_alias_mapping(__u64 *start, size_t len, unsigned long offset)
{
*start = (unsigned long)area_dst_alias + offset;
}
struct uffd_test_ops {
unsigned long expected_ioctls;
void (*allocate_area)(void **alloc_area);
@@ -332,7 +355,7 @@ 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 = {