ssize_t size;
ssize_t ret;
static int vsd_queue_file_io(struct tgt_cmd *cmd, int op){	struct file *file = cmd->device->file;	ssize_t size;	struct iovec *iov;	loff_t pos = cmd->offset;	iov = sg_to_iovec(cmd->sg, cmd->sg_count);	if (!iov)		return -ENOMEM;	if (op == READ)		size = generic_file_readv(file, iov, cmd->sg_count, &pos);	else		size = generic_file_writev(file, iov, cmd->sg_count, &pos);	kfree(iov);/* not yet used	if (sync)		err = sync_page_range(inode, inode->i_mapping, pos,				      (size_t) cmd->bufflen);*/	return size;}