path: root/drivers/target/iscsi/iscsi_target_erl0.c

/******************************************************************************
 * This file contains error recovery level zero functions used by
 * the iSCSI Target driver.
 *
 * \u00a9 Copyright 2007-2011 RisingTide Systems LLC.
 *
 * Licensed to the Linux Foundation under the General Public License (GPL) version 2.
 *
 * Author: Nicholas A. Bellinger <nab@linux-iscsi.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 ******************************************************************************/

#include <scsi/iscsi_proto.h>
#include <target/target_core_base.h>
#include <target/target_core_transport.h>

#include "iscsi_target_core.h"
#include "iscsi_target_seq_pdu_list.h"
#include "iscsi_target_tq.h"
#include "iscsi_target_erl0.h"
#include "iscsi_target_erl1.h"
#include "iscsi_target_erl2.h"
#include "iscsi_target_util.h"
#include "iscsi_target.h"

/*
 *	Used to set values in struct iscsi_cmd that iscsit_dataout_check_sequence()
 *	checks against to determine a PDU's Offset+Length is within the current
 *	DataOUT Sequence.  Used for DataSequenceInOrder=Yes only.
 */
void iscsit_set_dataout_sequence_values(
	struct iscsi_cmd *cmd)
{
	struct iscsi_conn *conn = cmd->conn;
	/*
	 * Still set seq_start_offset and seq_end_offset for Unsolicited
	 * DataOUT, even if DataSequenceInOrder=No.
	 */
	if (cmd->unsolicited_data) {
		cmd->seq_start_offset = cmd->write_data_done;
		cmd->seq_end_offset = (cmd->write_data_done +
			(cmd->data_length >
			 conn->sess->sess_ops->FirstBurstLength) ?
			conn->sess->sess_ops->FirstBurstLength : cmd->data_length);
		return;
	}

	if (!conn->sess->sess_ops->DataSequenceInOrder)
		return;

	if (!cmd->seq_start_offset && !cmd->seq_end_offset) {
		cmd->seq_start_offset = cmd->write_data_done;
		cmd->seq_end_offset = (cmd->data_length >
			conn->sess->sess_ops->MaxBurstLength) ?
			(cmd->write_data_done +
			conn->sess->sess_ops->MaxBurstLength) : cmd->data_length;
	} else {
		cmd->seq_start_offset = cmd->seq_end_offset;
		cmd->seq_end_offset = ((cmd->seq_end_offset +
			conn->sess->sess_ops->MaxBurstLength) >=
			cmd->data_length) ? cmd->data_length :
			(cmd->seq_end_offset +
			 conn->sess->sess_ops->MaxBurstLength);
	}
}

static int iscsit_dataout_within_command_recovery_check(
	struct iscsi_cmd *cmd,
	unsigned char *buf)
{
	struct iscsi_conn *conn = cmd->conn;
	struct iscsi_data *hdr = (struct iscsi_data *) buf;
	u32 payload_length = ntoh24(hdr->dlength);

	/*
	 * We do the within-command recovery checks here as it is
	 * the first function called in iscsi_check_pre_dataout().
	 * Basically, if we are in within-command recovery and
	 * the PDU does not contain the offset the sequence needs,
	 * dump the payload.
	 *
	 * This only applies to DataPDUInOrder=Yes, for
	 * DataPDUInOrder=No we only re-request the failed PDU
	 * and check that all PDUs in a sequence are received
	 * upon end of sequence.
	 */
	if (conn->sess->sess_ops->DataSequenceInOrder) {
		if ((cmd->cmd_flags & ICF_WITHIN_COMMAND_RECOVERY) &&
		    (cmd->write_data_done != hdr->offset))
			goto dump;

		cmd->cmd_flags &= ~ICF_WITHIN_COMMAND_RECOVERY;
	} else {
		struct iscsi_seq *seq;

		seq = iscsit_get_seq_holder(cmd, hdr->offset, payload_length);
		if (!seq)
			return DATAOUT_CANNOT_RECOVER;
		/*
		 * Set the struct iscsi_seq pointer to reuse later.
		 */
		cmd->seq_ptr = seq;

		if (conn->sess->sess_ops->DataPDUInOrder) {
			if ((seq->status ==
			     DATAOUT_SEQUENCE_WITHIN_COMMAND_RECOVERY) &&
			   ((seq->offset != hdr->offset) ||
			    (seq->data_sn != hdr->datasn)))
				goto dump;
		} else {
			if ((seq->status ==
			     DATAOUT_SEQUENCE_WITHIN_COMMAND_RECOVERY) &&
			    (seq->data_sn != hdr->datasn))
				goto dump;
		}

		if (seq->status == DATAOUT_SEQUENCE_COMPLETE)
			goto dump;

		if (seq->status != DATAOUT_SEQUENCE_COMPLETE)
			seq->status = 0;
	}

	return DATAOUT_NORMAL;

dump:
	pr_err("Dumping DataOUT PDU Offset: %u Length: %d DataSN:"
		" 0x%08x\n", hdr->offset, payload_length, hdr->datasn);
	return iscsit_dump_data_payload(conn, payload_length, 1);
}

static int iscsit_dataout_check_unsolicited_sequence(
	struct iscsi_cmd *cmd,
	unsigned char *buf)
{
	u32 first_burst_len;
	struct iscsi_conn *conn = cmd->conn;
	struct iscsi_data *hdr = (struct iscsi_data *) buf;