blkdev_write_iter: expand generic_file_checks() call in there

ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)

{

	struct file *file = iocb->ki_filp;

	struct inode *bd_inode = file->f_mapping->host;

	loff_t size = i_size_read(bd_inode);

	struct blk_plug plug;

	ssize_t ret;

	size_t count = iov_iter_count(from);

	ret = generic_write_checks(file, &iocb->ki_pos, &count, 1);

	if (ret)

		return ret;

	if (bdev_read_only(I_BDEV(bd_inode)))

		return -EPERM;

	if (count == 0)

	if (!iov_iter_count(from))

		return 0;

	iov_iter_truncate(from, count);

	if (iocb->ki_pos >= size)

		return -ENOSPC;

	iov_iter_truncate(from, size - iocb->ki_pos);

	blk_start_plug(&plug);

	ret = __generic_file_write_iter(iocb, from);