The patch titled
Subject: userfaultfd/selftests: create alias mappings in the shmem test
has been added to the -mm tree. Its filename is
userfaultfd-selftests-create-alias-mappings-in-the-shmem-test.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/userfaultfd-selftests-create-alias-mappings-in-the-shmem-test.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/userfaultfd-selftests-create-alias-mappings-in-the-shmem-test.patch
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------------------------------------------------------
From: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
Subject: 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/20210302000133.272579-4-axelrasmussen@xxxxxxxxxx
Signed-off-by: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Brian Geffon <bgeffon@xxxxxxxxxx>
Cc: Cannon Matthews <cannonmatthews@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: "Dr . David Alan Gilbert" <dgilbert@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Jerome Glisse <jglisse@xxxxxxxxxx>
Cc: Joe Perches <joe@xxxxxxxxxxx>
Cc: Lokesh Gidra <lokeshgidra@xxxxxxxxxx>
Cc: Michel Lespinasse <walken@xxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Cc: Mina Almasry <almasrymina@xxxxxxxxxx>
Cc: Oliver Upton <oupton@xxxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Shaohua Li <shli@xxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: Wang Qing <wangqing@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/vm/userfaultfd.c | 29 ++++++++++++++++++---
1 file changed, 26 insertions(+), 3 deletions(-)
--- a/tools/testing/selftests/vm/userfaultfd.c~userfaultfd-selftests-create-alias-mappings-in-the-shmem-test
+++ a/tools/testing/selftests/vm/userfaultfd.c
@@ -298,8 +298,9 @@ static int shmem_release_pages(char *rel
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);
@@ -308,12 +309,34 @@ static void shmem_allocate_area(void **a
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);
@@ -341,7 +364,7 @@ static struct uffd_test_ops shmem_uffd_t
.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 = {
_
Patches currently in -mm which might be from axelrasmussen@xxxxxxxxxx are
userfaultfd-add-minor-fault-registration-mode.patch
userfaultfd-disable-huge-pmd-sharing-for-minor-registered-vmas.patch
userfaultfd-hugetlbfs-only-compile-uffd-helpers-if-config-enabled.patch
userfaultfd-add-uffdio_continue-ioctl.patch
userfaultfd-update-documentation-to-describe-minor-fault-handling.patch
userfaultfd-selftests-add-test-exercising-minor-fault-handling.patch
userfaultfd-support-minor-fault-handling-for-shmem.patch
userfaultfd-selftests-use-memfd_create-for-shmem-test-type.patch
userfaultfd-selftests-create-alias-mappings-in-the-shmem-test.patch
userfaultfd-selftests-reinitialize-test-context-in-each-test.patch
userfaultfd-selftests-exercise-minor-fault-handling-shmem-support.patch
