int iscsit_fe_sendpage_sg()

in iscsi/iscsi_target_util.c [1076:1172]

• 79 lines of code
• 15 McCabe index (conditional complexity)

int iscsit_fe_sendpage_sg(
	struct iscsi_cmd *cmd,
	struct iscsi_conn *conn)
{
	struct scatterlist *sg = cmd->first_data_sg;
	struct kvec iov;
	u32 tx_hdr_size, data_len;
	u32 offset = cmd->first_data_sg_off;
	int tx_sent, iov_off;

send_hdr:
	tx_hdr_size = ISCSI_HDR_LEN;
	if (conn->conn_ops->HeaderDigest)
		tx_hdr_size += ISCSI_CRC_LEN;

	iov.iov_base = cmd->pdu;
	iov.iov_len = tx_hdr_size;

	tx_sent = tx_data(conn, &iov, 1, tx_hdr_size);
	if (tx_hdr_size != tx_sent) {
		if (tx_sent == -EAGAIN) {
			pr_err("tx_data() returned -EAGAIN\n");
			goto send_hdr;
		}
		return -1;
	}

	data_len = cmd->tx_size - tx_hdr_size - cmd->padding;
	/*
	 * Set iov_off used by padding and data digest tx_data() calls below
	 * in order to determine proper offset into cmd->iov_data[]
	 */
	if (conn->conn_ops->DataDigest) {
		data_len -= ISCSI_CRC_LEN;
		if (cmd->padding)
			iov_off = (cmd->iov_data_count - 2);
		else
			iov_off = (cmd->iov_data_count - 1);
	} else {
		iov_off = (cmd->iov_data_count - 1);
	}
	/*
	 * Perform sendpage() for each page in the scatterlist
	 */
	while (data_len) {
		u32 space = (sg->length - offset);
		u32 sub_len = min_t(u32, data_len, space);
send_pg:
		tx_sent = conn->sock->ops->sendpage(conn->sock,
					sg_page(sg), sg->offset + offset, sub_len, 0);
		if (tx_sent != sub_len) {
			if (tx_sent == -EAGAIN) {
				pr_err("tcp_sendpage() returned"
						" -EAGAIN\n");
				goto send_pg;
			}

			pr_err("tcp_sendpage() failure: %d\n",
					tx_sent);
			return -1;
		}

		data_len -= sub_len;
		offset = 0;
		sg = sg_next(sg);
	}

send_padding:
	if (cmd->padding) {
		struct kvec *iov_p = &cmd->iov_data[iov_off++];

		tx_sent = tx_data(conn, iov_p, 1, cmd->padding);
		if (cmd->padding != tx_sent) {
			if (tx_sent == -EAGAIN) {
				pr_err("tx_data() returned -EAGAIN\n");
				goto send_padding;
			}
			return -1;
		}
	}

send_datacrc:
	if (conn->conn_ops->DataDigest) {
		struct kvec *iov_d = &cmd->iov_data[iov_off];

		tx_sent = tx_data(conn, iov_d, 1, ISCSI_CRC_LEN);
		if (ISCSI_CRC_LEN != tx_sent) {
			if (tx_sent == -EAGAIN) {
				pr_err("tx_data() returned -EAGAIN\n");
				goto send_datacrc;
			}
			return -1;
		}
	}

	return 0;
}