userfaultfd: non-cooperative: selftest: add ufd parameter to copy_page

With future addition of event tests, copy_page will be called with
different userfault file descriptors

Link: http://lkml.kernel.org/r/20161216144821.5183-40-aarcange@redhat.com
Signed-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/userfaultfd.c

@@ -317,7 +317,7 @@ static void *locking_thread(void *arg)
 	return NULL;
 }
 
-static int copy_page(unsigned long offset)
+static int copy_page(int ufd, unsigned long offset)
 {
 	struct uffdio_copy uffdio_copy;
 
@@ -329,7 +329,7 @@ static int copy_page(unsigned long offset)
 	uffdio_copy.len = page_size;
 	uffdio_copy.mode = 0;
 	uffdio_copy.copy = 0;
-	if (ioctl(uffd, UFFDIO_COPY, &uffdio_copy)) {
+	if (ioctl(ufd, UFFDIO_COPY, &uffdio_copy)) {
 		/* real retval in ufdio_copy.copy */
 		if (uffdio_copy.copy != -EEXIST)
 			fprintf(stderr, "UFFDIO_COPY error %Ld\n",
@@ -386,7 +386,7 @@ static void *uffd_poll_thread(void *arg)
 		offset = (char *)(unsigned long)msg.arg.pagefault.address -
 			 area_dst;
 		offset &= ~(page_size-1);
-		if (copy_page(offset))
+		if (copy_page(uffd, offset))
 			userfaults++;
 	}
 	return (void *)userfaults;
@@ -424,7 +424,7 @@ static void *uffd_read_thread(void *arg)
 		offset = (char *)(unsigned long)msg.arg.pagefault.address -
 			 area_dst;
 		offset &= ~(page_size-1);
-		if (copy_page(offset))
+		if (copy_page(uffd, offset))
 			(*this_cpu_userfaults)++;
 	}
 	return (void *)NULL;
@@ -438,7 +438,7 @@ static void *background_thread(void *arg)
 	for (page_nr = cpu * nr_pages_per_cpu;
 	     page_nr < (cpu+1) * nr_pages_per_cpu;
 	     page_nr++)
-		copy_page(page_nr * page_size);
+		copy_page(uffd, page_nr * page_size);
 
 	return NULL;
 }