Re: [PATCH 11/29] selftests/mm: Drop test_uffdio_zeropage_eexist

Mike Rapoport
2023-04-07T09:49:01Z

On Thu, Mar 30, 2023 at 12:07:17PM -0400, Peter Xu wrote:
> The idea was trying to flip this var in the alarm handler from time to time
> to test -EEXIST of UFFDIO_ZEROPAGE, but firstly it's only used in the
> zeropage test so probably only used once, meanwhile we passed
> "retry==false" so it'll never got tested anyway.
>
> Drop both sides so we always test UFFDIO_ZEROPAGE retries if has_zeropage
> is set (!hugetlb).
>
> One more thing to do is doing UFFDIO_REGISTER for the alias buffer too,
> because otherwise the test won't even pass! We were just lucky that this
> test never really got ran at all.
>
> Signed-off-by: Peter Xu <peterx@redhat.com>

Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>

> ---
> tools/testing/selftests/mm/userfaultfd.c | 20 +++++++++++---------
> 1 file changed, 11 insertions(+), 9 deletions(-)
>
> diff --git a/tools/testing/selftests/mm/userfaultfd.c b/tools/testing/selftests/mm/userfaultfd.c
> index d724f1c78847..3487ec0bfcc8 100644
> --- a/tools/testing/selftests/mm/userfaultfd.c
> +++ b/tools/testing/selftests/mm/userfaultfd.c
> @@ -88,7 +88,6 @@ static bool test_dev_userfaultfd;
> /* exercise the test_uffdio_*_eexist every ALARM_INTERVAL_SECS */
> #define ALARM_INTERVAL_SECS 10
> static volatile bool test_uffdio_copy_eexist = true;
> -static volatile bool test_uffdio_zeropage_eexist = true;
> /* Whether to test uffd write-protection */
> static bool test_uffdio_wp = true;
> /* Whether to test uffd minor faults */
> @@ -1114,7 +1113,7 @@ static void retry_uffdio_zeropage(int ufd,
> }
> }
>
> -static int __uffdio_zeropage(int ufd, unsigned long offset, bool retry)
> +static int __uffdio_zeropage(int ufd, unsigned long offset)
> {
> struct uffdio_zeropage uffdio_zeropage;
> int ret;
> @@ -1138,11 +1137,8 @@ static int __uffdio_zeropage(int ufd, unsigned long offset, bool retry)
> if (res != page_size) {
> err("UFFDIO_ZEROPAGE unexpected size");
> } else {
> - if (test_uffdio_zeropage_eexist && retry) {
> - test_uffdio_zeropage_eexist = false;
> - retry_uffdio_zeropage(ufd, &uffdio_zeropage,
> - offset);
> - }
> + retry_uffdio_zeropage(ufd, &uffdio_zeropage,
> + offset);
> return 1;
> }
> } else
> @@ -1153,7 +1149,7 @@ static int __uffdio_zeropage(int ufd, unsigned long offset, bool retry)
>
> static int uffdio_zeropage(int ufd, unsigned long offset)
> {
> - return __uffdio_zeropage(ufd, offset, false);
> + return __uffdio_zeropage(ufd, offset);
> }
>
> /* exercise UFFDIO_ZEROPAGE */
> @@ -1177,6 +1173,13 @@ static int userfaultfd_zeropage_test(void)
> assert_expected_ioctls_present(
> uffdio_register.mode, uffdio_register.ioctls);
>
> + if (area_dst_alias) {
> + /* Needed this to test zeropage-retry on shared memory */
> + uffdio_register.range.start = (unsigned long) area_dst_alias;
> + if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
> + err("register failure");
> + }
> +
> if (uffdio_zeropage(uffd, 0))
> if (my_bcmp(area_dst, zeropage, page_size))
> err("zeropage is not zero");
> @@ -1763,7 +1766,6 @@ static void sigalrm(int sig)
> if (sig != SIGALRM)
> abort();
> test_uffdio_copy_eexist = true;
> - test_uffdio_zeropage_eexist = true;
> alarm(ALARM_INTERVAL_SECS);
> }
>
> --
> 2.39.1
>

--
Sincerely yours,
Mike.