Commit 5bb23edb authored by Axel Rasmussen's avatar Axel Rasmussen Committed by Linus Torvalds
Browse files

userfaultfd/selftests: create alias mappings in the shmem test 

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: 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 fa2c2b58

tools/testing/selftests/vm/userfaultfd.c

+19 −3
Original line number Diff line number Diff line
@@ -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 = {