userfaultfd: non-cooperative: selftest: enable REMOVE event test for shmem

Now when madvise(MADV_REMOVE) notifies uffd reader, we should verify
that appliciation actually sees zeros at the removed range.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Mike Rapoport <[email protected]>
Reviewed-by: Andrea Arcangeli <[email protected]>
Cc: Hillf Danton <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Author: rppt

tools/testing/selftests/vm/userfaultfd.c

@@ -569,9 +569,9 @@ static int userfaultfd_open(int features)
  * part is accessed after mremap. Since hugetlbfs does not support
  * mremap, the entire monitored area is accessed in a single pass for
  * HUGETLB_TEST.
- * The release of the pages currently generates event only for
+ * The release of the pages currently generates event for shmem and
  * anonymous memory (UFFD_EVENT_REMOVE), hence it is not checked
- * for hugetlb and shmem.
+ * for hugetlb.
  */
 static int faulting_process(void)
 {
@@ -610,15 +610,13 @@ static int faulting_process(void)
 		}
 	}
 
-#ifndef SHMEM_TEST
 	if (release_pages(area_dst))
 		return 1;
 
 	for (nr = 0; nr < nr_pages; nr++) {
 		if (my_bcmp(area_dst + nr * page_size, zeropage, page_size))
 			fprintf(stderr, "nr %lu is not zero\n", nr), exit(1);
 	}
-#endif /* SHMEM_TEST */
 
 #endif /* HUGETLB_TEST */