selftests/mm: drop test_uffdio_zeropage_eexist

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.

Link: https://lkml.kernel.org/r/20230412164238.328238-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/tools/testing/selftests/mm/userfaultfd.c b/tools/testing/selftests/mm/userfaultfd.c
index d724f1c..3487ec0 100644 (file)
--- 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);
 }