selftests/vm: Set mmap()'s fd as -1 for MAP_ANONYMOUS flag

Man page of mmap() says that portable applications should ensure fd
argument to be -1 if MAP_ANONYMOUS flag is set as below:
```
The  mapping is not backed by any file; its contents are initialized to
zero.  The fd and offset arguments are ignored; however, some
implementations require  fd  to be  -1  if  MAP_ANONYMOUS  (or
MAP_ANON)  is specified, and portable applications
should ensure this.
```

However, few mmap() calls under selftests/vm/ uses 0 as fd though they
use MAP_ANONYMOUS flag.  This commit changes the argument to be -1 as
recommended.
Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

tools/testing/selftests/vm/map_hugetlb.c

@@ -62,7 +62,7 @@ int main(void)
 	void *addr;
 	int ret;
 
-	addr = mmap(ADDR, LENGTH, PROTECTION, FLAGS, 0, 0);
+	addr = mmap(ADDR, LENGTH, PROTECTION, FLAGS, -1, 0);
 	if (addr == MAP_FAILED) {
 		perror("mmap");
 		exit(1);

tools/testing/selftests/vm/mlock2-tests.c

@@ -293,7 +293,7 @@ static int test_mlock_lock()
 	unsigned long page_size = getpagesize();
 
 	map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
-		   MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
+		   MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 	if (map == MAP_FAILED) {
 		perror("test_mlock_locked mmap");
 		goto out;
@@ -402,7 +402,7 @@ static int test_mlock_onfault()
 	unsigned long page_size = getpagesize();
 
 	map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
-		   MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
+		   MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 	if (map == MAP_FAILED) {
 		perror("test_mlock_locked mmap");
 		goto out;
@@ -445,7 +445,7 @@ static int test_lock_onfault_of_present()
 	uint64_t page1_flags, page2_flags;
 
 	map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
-		   MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
+		   MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 	if (map == MAP_FAILED) {
 		perror("test_mlock_locked mmap");
 		goto out;
@@ -492,7 +492,7 @@ static int test_munlockall()
 	unsigned long page_size = getpagesize();
 
 	map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
-		   MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
+		   MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 
 	if (map == MAP_FAILED) {
 		perror("test_munlockall mmap");
@@ -518,7 +518,7 @@ static int test_munlockall()
 	munmap(map, 2 * page_size);
 
 	map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
-		   MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
+		   MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 
 	if (map == MAP_FAILED) {
 		perror("test_munlockall second mmap");
@@ -573,7 +573,7 @@ static int test_vma_management(bool call_mlock)
 	struct vm_boundaries page3;
 
 	map = mmap(NULL, 3 * page_size, PROT_READ | PROT_WRITE,
-		   MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
+		   MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 	if (map == MAP_FAILED) {
 		perror("mmap()");
 		return ret;

tools/testing/selftests/vm/on-fault-limit.c

@@ -26,7 +26,7 @@ static int test_limit(void)
 	}
 
 	map = mmap(NULL, 2 * lims.rlim_max, PROT_READ | PROT_WRITE,
-		   MAP_PRIVATE | MAP_ANONYMOUS | MAP_POPULATE, 0, 0);
+		   MAP_PRIVATE | MAP_ANONYMOUS | MAP_POPULATE, -1, 0);
 	if (map != MAP_FAILED)
 		printf("mmap should have failed, but didn't\n");
 	else {

tools/testing/selftests/vm/thuge-gen.c

@@ -146,7 +146,7 @@ void test_mmap(unsigned long size, unsigned flags)
 
 	before = read_free(size);
 	map = mmap(NULL, size*NUM_PAGES, PROT_READ|PROT_WRITE,
-			MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB|flags, 0, 0);
+			MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB|flags, -1, 0);
 
 	if (map == (char *)-1) err("mmap");
 	memset(map, 0xff, size*NUM_PAGES);