userfaultfd: shmem: add userfaultfd_shmem test

The test verifies that anonymous shared mapping can be used with userfault
using the existing testing method.  The shared memory area is allocated
using mmap(..., MAP_SHARED | MAP_ANONYMOUS, ...) and released using
madvise(MADV_REMOVE)

Link: http://lkml.kernel.org/r/20161216144821.5183-35-aarcange@redhat.comSigned-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Michael Rapoport <RAPOPORT@il.ibm.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

tools/testing/selftests/vm/Makefile

@@ -11,6 +11,7 @@ BINARIES += thuge-gen
 BINARIES += transhuge-stress
 BINARIES += userfaultfd
 BINARIES += userfaultfd_hugetlb
+BINARIES += userfaultfd_shmem
 BINARIES += mlock-random-test
 
 all: $(BINARIES)
@@ -22,6 +23,9 @@ userfaultfd: userfaultfd.c ../../../../usr/include/linux/kernel.h
 userfaultfd_hugetlb: userfaultfd.c ../../../../usr/include/linux/kernel.h
 	$(CC) $(CFLAGS) -DHUGETLB_TEST -O2 -o $@ $< -lpthread
 
+userfaultfd_shmem: userfaultfd.c ../../../../usr/include/linux/kernel.h
+	$(CC) $(CFLAGS) -DSHMEM_TEST -O2 -o $@ $< -lpthread
+
 mlock-random-test: mlock-random-test.c
 	$(CC) $(CFLAGS) -o $@ $< -lcap
 

tools/testing/selftests/vm/run_vmtests

@@ -116,6 +116,17 @@ else
 fi
 rm -f $mnt/ufd_test_file
 
+echo "----------------------------"
+echo "running userfaultfd_shmem"
+echo "----------------------------"
+./userfaultfd_shmem 128 32
+if [ $? -ne 0 ]; then
+	echo "[FAIL]"
+	exitcode=1
+else
+	echo "[PASS]"
+fi
+
 #cleanup
 umount $mnt
 rm -rf $mnt

tools/testing/selftests/vm/userfaultfd.c

@@ -101,8 +101,9 @@ pthread_attr_t attr;
 				 ~(unsigned long)(sizeof(unsigned long long) \
 						  -  1)))
 
-#ifndef HUGETLB_TEST
+#if !defined(HUGETLB_TEST) && !defined(SHMEM_TEST)
 
+/* Anonymous memory */
 #define EXPECTED_IOCTLS		((1 << _UFFDIO_WAKE) | \
 				 (1 << _UFFDIO_COPY) | \
 				 (1 << _UFFDIO_ZEROPAGE))
@@ -127,10 +128,13 @@ static void allocate_area(void **alloc_area)
 	}
 }
 
-#else /* HUGETLB_TEST */
+#else /* HUGETLB_TEST or SHMEM_TEST */
 
 #define EXPECTED_IOCTLS		UFFD_API_RANGE_IOCTLS_BASIC
 
+#ifdef HUGETLB_TEST
+
+/* HugeTLB memory */
 static int release_pages(char *rel_area)
 {
 	int ret = 0;
@@ -162,8 +166,37 @@ static void allocate_area(void **alloc_area)
 		huge_fd_off0 = *alloc_area;
 }
 
+#elif defined(SHMEM_TEST)
+
+/* Shared memory */
+static int release_pages(char *rel_area)
+{
+	int ret = 0;
+
+	if (madvise(rel_area, nr_pages * page_size, MADV_REMOVE)) {
+		perror("madvise");
+		ret = 1;
+	}
+
+	return ret;
+}
+
+static void allocate_area(void **alloc_area)
+{
+	*alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
+			   MAP_ANONYMOUS | MAP_SHARED, -1, 0);
+	if (*alloc_area == MAP_FAILED) {
+		fprintf(stderr, "shared memory mmap failed\n");
+		*alloc_area = NULL;
+	}
+}
+
+#else /* SHMEM_TEST */
+#error "Undefined test type"
 #endif /* HUGETLB_TEST */
 
+#endif /* !defined(HUGETLB_TEST) && !defined(SHMEM_TEST) */
+
 static int my_bcmp(char *str1, char *str2, size_t n)
 {
 	unsigned long i;