switch simple cases of fget_light to fdget

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/ioctl.c b/fs/ioctl.c
index 29167be..3bdad6d 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -603,21 +603,14 @@
 
 SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
 {
-	struct file *filp;
-	int error = -EBADF;
-	int fput_needed;
+	int error;
+	struct fd f = fdget(fd);
 
-	filp = fget_light(fd, &fput_needed);
-	if (!filp)
-		goto out;
-
-	error = security_file_ioctl(filp, cmd, arg);
-	if (error)
-		goto out_fput;
-
-	error = do_vfs_ioctl(filp, fd, cmd, arg);
- out_fput:
-	fput_light(filp, fput_needed);
- out:
+	if (!f.file)
+		return -EBADF;
+	error = security_file_ioctl(f.file, cmd, arg);
+	if (!error)
+		error = do_vfs_ioctl(f.file, fd, cmd, arg);
+	fdput(f);
 	return error;
 }