[PATCH] introduce __blkdev_driver_ioctl()

Analog of blkdev_driver_ioctl() with sane arguments.  For
now uses fake struct file, by the end of the series it won't
and blkdev_driver_ioctl() will become a wrapper around it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index c681d5e..d85c65a 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -1400,13 +1400,10 @@
 {
 	struct multipath *m = (struct multipath *) ti->private;
 	struct block_device *bdev = NULL;
+	fmode_t mode = 0;
 	unsigned long flags;
-	struct file fake_file = {};
-	struct dentry fake_dentry = {};
 	int r = 0;
 
-	fake_file.f_path.dentry = &fake_dentry;
-
 	spin_lock_irqsave(&m->lock, flags);
 
 	if (!m->current_pgpath)
@@ -1414,8 +1411,7 @@
 
 	if (m->current_pgpath) {
 		bdev = m->current_pgpath->path.dev->bdev;
-		fake_dentry.d_inode = bdev->bd_inode;
-		fake_file.f_mode = m->current_pgpath->path.dev->mode;
+		mode = m->current_pgpath->path.dev->mode;
 	}
 
 	if (m->queue_io)
@@ -1425,8 +1421,7 @@
 
 	spin_unlock_irqrestore(&m->lock, flags);
 
-	return r ? : blkdev_driver_ioctl(bdev->bd_inode, &fake_file,
-					 bdev->bd_disk, cmd, arg);
+	return r ? : __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 }
 
 /*-----------------------------------------------------------------