[mirror_ubuntu-artful-kernel.git] / drivers / target / iscsi / iscsi_target_erl2.c

/*******************************************************************************
 * This file contains error recovery level two functions used by
 * the iSCSI Target driver.
 *
 * (c) Copyright 2007-2013 Datera, Inc.
 *
 * 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_fabric.h>

#include <target/iscsi/iscsi_target_core.h>
#include "iscsi_target_datain_values.h"
#include "iscsi_target_util.h"
#include "iscsi_target_erl0.h"
#include "iscsi_target_erl1.h"
#include "iscsi_target_erl2.h"
#include "iscsi_target.h"

/*
 *	FIXME: Does RData SNACK apply here as well?
 */
void iscsit_create_conn_recovery_datain_values(
	struct iscsi_cmd *cmd,
	__be32 exp_data_sn)
{
	u32 data_sn = 0;
	struct iscsi_conn *conn = cmd->conn;

	cmd->next_burst_len = 0;
	cmd->read_data_done = 0;

	while (be32_to_cpu(exp_data_sn) > data_sn) {
		if ((cmd->next_burst_len +
		     conn->conn_ops->MaxRecvDataSegmentLength) <
		     conn->sess->sess_ops->MaxBurstLength) {
			cmd->read_data_done +=
			       conn->conn_ops->MaxRecvDataSegmentLength;
			cmd->next_burst_len +=
			       conn->conn_ops->MaxRecvDataSegmentLength;
		} else {
			cmd->read_data_done +=
				(conn->sess->sess_ops->MaxBurstLength -
				cmd->next_burst_len);
			cmd->next_burst_len = 0;
		}
		data_sn++;
	}
}

void iscsit_create_conn_recovery_dataout_values(
	struct iscsi_cmd *cmd)
{
	u32 write_data_done = 0;
	struct iscsi_conn *conn = cmd->conn;

	cmd->data_sn = 0;
	cmd->next_burst_len = 0;

	while (cmd->write_data_done > write_data_done) {
		if ((write_data_done + conn->sess->sess_ops->MaxBurstLength) <=
		     cmd->write_data_done)
			write_data_done += conn->sess->sess_ops->MaxBurstLength;
		else
			break;
	}

	cmd->write_data_done = write_data_done;
}

static int iscsit_attach_active_connection_recovery_entry(
	struct iscsi_session *sess,
	struct iscsi_conn_recovery *cr)
{
	spin_lock(&sess->cr_a_lock);
	list_add_tail(&cr->cr_list, &sess->cr_active_list);
	spin_unlock(&sess->cr_a_lock);

	return 0;
}

static int iscsit_attach_inactive_connection_recovery_entry(
	struct iscsi_session *sess,
	struct iscsi_conn_recovery *cr)
{
	spin_lock(&sess->cr_i_lock);
	list_add_tail(&cr->cr_list, &sess->cr_inactive_list);

	sess->conn_recovery_count++;
	pr_debug("Incremented connection recovery count to %u for"
		" SID: %u\n", sess->conn_recovery_count, sess->sid);
	spin_unlock(&sess->cr_i_lock);

	return 0;
}

struct iscsi_conn_recovery *iscsit_get_inactive_connection_recovery_entry(
	struct iscsi_session *sess,
	u16 cid)
{
	struct iscsi_conn_recovery *cr;

	spin_lock(&sess->cr_i_lock);
	list_for_each_entry(cr, &sess->cr_inactive_list, cr_list) {
		if (cr->cid == cid) {
			spin_unlock(&sess->cr_i_lock);
			return cr;
		}
	}
	spin_unlock(&sess->cr_i_lock);

	return NULL;
}

void iscsit_free_connection_recovery_entires(struct iscsi_session *sess)
{
	struct iscsi_cmd *cmd, *cmd_tmp;
	struct iscsi_conn_recovery *cr, *cr_tmp;

	spin_lock(&sess->cr_a_lock);
	list_for_each_entry_safe(cr, cr_tmp, &sess->cr_active_list, cr_list) {
		list_del(&cr->cr_list);
		spin_unlock(&sess->cr_a_lock);

		spin_lock(&cr->conn_recovery_cmd_lock);
		list_for_each_entry_safe(cmd, cmd_tmp,
				&cr->conn_recovery_cmd_list, i_conn_node) {

			list_del_init(&cmd->i_conn_node);
			cmd->conn = NULL;
			spin_unlock(&cr->conn_recovery_cmd_lock);
			iscsit_free_cmd(cmd, true);
			spin_lock(&cr->conn_recovery_cmd_lock);
		}
		spin_unlock(&cr->conn_recovery_cmd_lock);
		spin_lock(&sess->cr_a_lock);

		kfree(cr);
	}
	spin_unlock(&sess->cr_a_lock);

	spin_lock(&sess->cr_i_lock);
	list_for_each_entry_safe(cr, cr_tmp, &sess->cr_inactive_list, cr_list) {
		list_del(&cr->cr_list);
		spin_unlock(&sess->cr_i_lock);

		spin_lock(&cr->conn_recovery_cmd_lock);
		list_for_each_entry_safe(cmd, cmd_tmp,
				&cr->conn_recovery_cmd_list, i_conn_node) {

			list_del_init(&cmd->i_conn_node);
			cmd->conn = NULL;
			spin_unlock(&cr->conn_recovery_cmd_lock);
			iscsit_free_cmd(cmd, true);
			spin_lock(&cr->conn_recovery_cmd_lock);
		}
		spin_unlock(&cr->conn_recovery_cmd_lock);
		spin_lock(&sess->cr_i_lock);

		kfree(cr);
	}
	spin_unlock(&sess->cr_i_lock);
}

int iscsit_remove_active_connection_recovery_entry(
	struct iscsi_conn_recovery *cr,
	struct iscsi_session *sess)
{
	spin_lock(&sess->cr_a_lock);
	list_del(&cr->cr_list);

	sess->conn_recovery_count--;
	pr_debug("Decremented connection recovery count to %u for"
		" SID: %u\n", sess->conn_recovery_count, sess->sid);
	spin_unlock(&sess->cr_a_lock);

	kfree(cr);

	return 0;
}

static void iscsit_remove_inactive_connection_recovery_entry(
	struct iscsi_conn_recovery *cr,
	struct iscsi_session *sess)
{
	spin_lock(&sess->cr_i_lock);
	list_del(&cr->cr_list);
	spin_unlock(&sess->cr_i_lock);
}

/*
 *	Called with cr->conn_recovery_cmd_lock help.
 */
int iscsit_remove_cmd_from_connection_recovery(
	struct iscsi_cmd *cmd,
	struct iscsi_session *sess)
{
	struct iscsi_conn_recovery *cr;

	if (!cmd->cr) {
		pr_err("struct iscsi_conn_recovery pointer for ITT: 0x%08x"
			" is NULL!\n", cmd->init_task_tag);
		BUG();
	}
	cr = cmd->cr;

	list_del_init(&cmd->i_conn_node);
	return --cr->cmd_count;
}

void iscsit_discard_cr_cmds_by_expstatsn(
	struct iscsi_conn_recovery *cr,
	u32 exp_statsn)
{
	u32 dropped_count = 0;
	struct iscsi_cmd *cmd, *cmd_tmp;
	struct iscsi_session *sess = cr->sess;

	spin_lock(&cr->conn_recovery_cmd_lock);
	list_for_each_entry_safe(cmd, cmd_tmp,
			&cr->conn_recovery_cmd_list, i_conn_node) {

		if (((cmd->deferred_i_state != ISTATE_SENT_STATUS) &&
		     (cmd->deferred_i_state != ISTATE_REMOVE)) ||
		     (cmd->stat_sn >= exp_statsn)) {
			continue;
		}

		dropped_count++;
		pr_debug("Dropping Acknowledged ITT: 0x%08x, StatSN:"
			" 0x%08x, CID: %hu.\n", cmd->init_task_tag,
				cmd->stat_sn, cr->cid);

		iscsit_remove_cmd_from_connection_recovery(cmd, sess);

		spin_unlock(&cr->conn_recovery_cmd_lock);
		iscsit_free_cmd(cmd, true);
		spin_lock(&cr->conn_recovery_cmd_lock);
	}
	spin_unlock(&cr->conn_recovery_cmd_lock);

	pr_debug("Dropped %u total acknowledged commands on"
		" CID: %hu less than old ExpStatSN: 0x%08x\n",
			dropped_count, cr->cid, exp_statsn);

	if (!cr->cmd_count) {
		pr_debug("No commands to be reassigned for failed"
			" connection CID: %hu on SID: %u\n",
			cr->cid, sess->sid);
		iscsit_remove_inactive_connection_recovery_entry(cr, sess);
		iscsit_attach_active_connection_recovery_entry(sess, cr);
		pr_debug("iSCSI connection recovery successful for CID:"
			" %hu on SID: %u\n", cr->cid, sess->sid);
		iscsit_remove_active_connection_recovery_entry(cr, sess);
	} else {
		iscsit_remove_inactive_connection_recovery_entry(cr, sess);
		iscsit_attach_active_connection_recovery_entry(sess, cr);
	}
}

int iscsit_discard_unacknowledged_ooo_cmdsns_for_conn(struct iscsi_conn *conn)
{
	u32 dropped_count = 0;
	struct iscsi_cmd *cmd, *cmd_tmp;
	struct iscsi_ooo_cmdsn *ooo_cmdsn, *ooo_cmdsn_tmp;
	struct iscsi_session *sess = conn->sess;

	mutex_lock(&sess->cmdsn_mutex);
	list_for_each_entry_safe(ooo_cmdsn, ooo_cmdsn_tmp,
			&sess->sess_ooo_cmdsn_list, ooo_list) {

		if (ooo_cmdsn->cid != conn->cid)
			continue;

		dropped_count++;
		pr_debug("Dropping unacknowledged CmdSN:"
		" 0x%08x during connection recovery on CID: %hu\n",
			ooo_cmdsn->cmdsn, conn->cid);
		iscsit_remove_ooo_cmdsn(sess, ooo_cmdsn);
	}
	mutex_unlock(&sess->cmdsn_mutex);

	spin_lock_bh(&conn->cmd_lock);
	list_for_each_entry_safe(cmd, cmd_tmp, &conn->conn_cmd_list, i_conn_node) {
		if (!(cmd->cmd_flags & ICF_OOO_CMDSN))
			continue;

		list_del_init(&cmd->i_conn_node);

		spin_unlock_bh(&conn->cmd_lock);
		iscsit_free_cmd(cmd, true);
		spin_lock_bh(&conn->cmd_lock);
	}
	spin_unlock_bh(&conn->cmd_lock);

	pr_debug("Dropped %u total unacknowledged commands on CID:"
		" %hu for ExpCmdSN: 0x%08x.\n", dropped_count, conn->cid,
				sess->exp_cmd_sn);
	return 0;
}

int iscsit_prepare_cmds_for_realligance(struct iscsi_conn *conn)
{
	u32 cmd_count = 0;
	struct iscsi_cmd *cmd, *cmd_tmp;
	struct iscsi_conn_recovery *cr;

	/*
	 * Allocate an struct iscsi_conn_recovery for this connection.
	 * Each struct iscsi_cmd contains an struct iscsi_conn_recovery pointer
	 * (struct iscsi_cmd->cr) so we need to allocate this before preparing the
	 * connection's command list for connection recovery.
	 */
	cr = kzalloc(sizeof(struct iscsi_conn_recovery), GFP_KERNEL);
	if (!cr) {
		pr_err("Unable to allocate memory for"
			" struct iscsi_conn_recovery.\n");
		return -1;
	}
	INIT_LIST_HEAD(&cr->cr_list);
	INIT_LIST_HEAD(&cr->conn_recovery_cmd_list);
	spin_lock_init(&cr->conn_recovery_cmd_lock);
	/*
	 * Only perform connection recovery on ISCSI_OP_SCSI_CMD or
	 * ISCSI_OP_NOOP_OUT opcodes.  For all other opcodes call
	 * list_del_init(&cmd->i_conn_node); to release the command to the
	 * session pool and remove it from the connection's list.
	 *
	 * Also stop the DataOUT timer, which will be restarted after
	 * sending the TMR response.
	 */
	spin_lock_bh(&conn->cmd_lock);
	list_for_each_entry_safe(cmd, cmd_tmp, &conn->conn_cmd_list, i_conn_node) {

		if ((cmd->iscsi_opcode != ISCSI_OP_SCSI_CMD) &&
		    (cmd->iscsi_opcode != ISCSI_OP_NOOP_OUT)) {
			pr_debug("Not performing realligence on"
				" Opcode: 0x%02x, ITT: 0x%08x, CmdSN: 0x%08x,"
				" CID: %hu\n", cmd->iscsi_opcode,
				cmd->init_task_tag, cmd->cmd_sn, conn->cid);

			list_del_init(&cmd->i_conn_node);
			spin_unlock_bh(&conn->cmd_lock);
			iscsit_free_cmd(cmd, true);
			spin_lock_bh(&conn->cmd_lock);
			continue;
		}

		/*
		 * Special case where commands greater than or equal to
		 * the session's ExpCmdSN are attached to the connection
		 * list but not to the out of order CmdSN list.  The one
		 * obvious case is when a command with immediate data
		 * attached must only check the CmdSN against ExpCmdSN
		 * after the data is received.  The special case below
		 * is when the connection fails before data is received,
		 * but also may apply to other PDUs, so it has been
		 * made generic here.
		 */
		if (!(cmd->cmd_flags & ICF_OOO_CMDSN) && !cmd->immediate_cmd &&
		     iscsi_sna_gte(cmd->cmd_sn, conn->sess->exp_cmd_sn)) {
			list_del_init(&cmd->i_conn_node);
			spin_unlock_bh(&conn->cmd_lock);
			iscsit_free_cmd(cmd, true);
			spin_lock_bh(&conn->cmd_lock);
			continue;
		}

		cmd_count++;
		pr_debug("Preparing Opcode: 0x%02x, ITT: 0x%08x,"
			" CmdSN: 0x%08x, StatSN: 0x%08x, CID: %hu for"
			" realligence.\n", cmd->iscsi_opcode,
			cmd->init_task_tag, cmd->cmd_sn, cmd->stat_sn,
			conn->cid);

		cmd->deferred_i_state = cmd->i_state;
		cmd->i_state = ISTATE_IN_CONNECTION_RECOVERY;

		if (cmd->data_direction == DMA_TO_DEVICE)
			iscsit_stop_dataout_timer(cmd);

		cmd->sess = conn->sess;

		list_del_init(&cmd->i_conn_node);
		spin_unlock_bh(&conn->cmd_lock);

		iscsit_free_all_datain_reqs(cmd);

		transport_wait_for_tasks(&cmd->se_cmd);
		/*
		 * Add the struct iscsi_cmd to the connection recovery cmd list
		 */
		spin_lock(&cr->conn_recovery_cmd_lock);
		list_add_tail(&cmd->i_conn_node, &cr->conn_recovery_cmd_list);
		spin_unlock(&cr->conn_recovery_cmd_lock);

		spin_lock_bh(&conn->cmd_lock);
		cmd->cr = cr;
		cmd->conn = NULL;
	}
	spin_unlock_bh(&conn->cmd_lock);
	/*
	 * Fill in the various values in the preallocated struct iscsi_conn_recovery.
	 */
	cr->cid = conn->cid;
	cr->cmd_count = cmd_count;
	cr->maxrecvdatasegmentlength = conn->conn_ops->MaxRecvDataSegmentLength;
	cr->maxxmitdatasegmentlength = conn->conn_ops->MaxXmitDataSegmentLength;
	cr->sess = conn->sess;

	iscsit_attach_inactive_connection_recovery_entry(conn->sess, cr);

	return 0;
}

int iscsit_connection_recovery_transport_reset(struct iscsi_conn *conn)
{
	atomic_set(&conn->connection_recovery, 1);

	if (iscsit_close_connection(conn) < 0)
		return -1;

	return 0;
}
Commit	Line	Data
e48354ce NB	1	/*******************************************************************************
	2	* This file contains error recovery level two functions used by
	3	* the iSCSI Target driver.
	4	*
4c76251e	5	* (c) Copyright 2007-2013 Datera, Inc.
e48354ce NB	6	*
	7	* Author: Nicholas A. Bellinger <nab@linux-iscsi.org>
	8	*
	9	* This program is free software; you can redistribute it and/or modify
	10	* it under the terms of the GNU General Public License as published by
	11	* the Free Software Foundation; either version 2 of the License, or
	12	* (at your option) any later version.
	13	*
	14	* This program is distributed in the hope that it will be useful,
	15	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	16	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	17	* GNU General Public License for more details.
	18	******************************************************************************/
	19
	20	#include <scsi/iscsi_proto.h>
	21	#include <target/target_core_base.h>
c4795fb2	22	#include <target/target_core_fabric.h>
e48354ce	23
67f091f2	24	#include <target/iscsi/iscsi_target_core.h>
e48354ce NB	25	#include "iscsi_target_datain_values.h"
	26	#include "iscsi_target_util.h"
	27	#include "iscsi_target_erl0.h"
	28	#include "iscsi_target_erl1.h"
	29	#include "iscsi_target_erl2.h"
	30	#include "iscsi_target.h"
	31
	32	/*
	33	* FIXME: Does RData SNACK apply here as well?
	34	*/
	35	void iscsit_create_conn_recovery_datain_values(
	36	struct iscsi_cmd *cmd,
50e5c87d	37	__be32 exp_data_sn)
e48354ce NB	38	{
	39	u32 data_sn = 0;
	40	struct iscsi_conn *conn = cmd->conn;
	41
	42	cmd->next_burst_len = 0;
	43	cmd->read_data_done = 0;
	44
50e5c87d	45	while (be32_to_cpu(exp_data_sn) > data_sn) {
e48354ce NB	46	if ((cmd->next_burst_len +
	47	conn->conn_ops->MaxRecvDataSegmentLength) <
	48	conn->sess->sess_ops->MaxBurstLength) {
	49	cmd->read_data_done +=
	50	conn->conn_ops->MaxRecvDataSegmentLength;
	51	cmd->next_burst_len +=
	52	conn->conn_ops->MaxRecvDataSegmentLength;
	53	} else {
	54	cmd->read_data_done +=
	55	(conn->sess->sess_ops->MaxBurstLength -
	56	cmd->next_burst_len);
	57	cmd->next_burst_len = 0;
	58	}
	59	data_sn++;
	60	}
	61	}
	62
	63	void iscsit_create_conn_recovery_dataout_values(
	64	struct iscsi_cmd *cmd)
	65	{
	66	u32 write_data_done = 0;
	67	struct iscsi_conn *conn = cmd->conn;
	68
	69	cmd->data_sn = 0;
	70	cmd->next_burst_len = 0;
	71
	72	while (cmd->write_data_done > write_data_done) {
	73	if ((write_data_done + conn->sess->sess_ops->MaxBurstLength) <=
	74	cmd->write_data_done)
	75	write_data_done += conn->sess->sess_ops->MaxBurstLength;
	76	else
	77	break;
	78	}
	79
	80	cmd->write_data_done = write_data_done;
	81	}
	82
	83	static int iscsit_attach_active_connection_recovery_entry(
	84	struct iscsi_session *sess,
	85	struct iscsi_conn_recovery *cr)
	86	{
	87	spin_lock(&sess->cr_a_lock);
	88	list_add_tail(&cr->cr_list, &sess->cr_active_list);
	89	spin_unlock(&sess->cr_a_lock);
	90
	91	return 0;
	92	}
	93
	94	static int iscsit_attach_inactive_connection_recovery_entry(
	95	struct iscsi_session *sess,
	96	struct iscsi_conn_recovery *cr)
	97	{
	98	spin_lock(&sess->cr_i_lock);
	99	list_add_tail(&cr->cr_list, &sess->cr_inactive_list);
	100
	101	sess->conn_recovery_count++;
	102	pr_debug("Incremented connection recovery count to %u for"
	103	" SID: %u\n", sess->conn_recovery_count, sess->sid);
	104	spin_unlock(&sess->cr_i_lock);
	105
	106	return 0;
	107	}
	108
	109	struct iscsi_conn_recovery *iscsit_get_inactive_connection_recovery_entry(
110	struct iscsi_session *sess,
111	u16 cid)
112	{
113	struct iscsi_conn_recovery *cr;
114
115	spin_lock(&sess->cr_i_lock);
116	list_for_each_entry(cr, &sess->cr_inactive_list, cr_list) {
117	if (cr->cid == cid) {
118	spin_unlock(&sess->cr_i_lock);
119	return cr;
120	}
121	}
122	spin_unlock(&sess->cr_i_lock);
123
124	return NULL;
125	}
126
127	void iscsit_free_connection_recovery_entires(struct iscsi_session *sess)
128	{
129	struct iscsi_cmd cmd, cmd_tmp;
130	struct iscsi_conn_recovery cr, cr_tmp;
131
132	spin_lock(&sess->cr_a_lock);
133	list_for_each_entry_safe(cr, cr_tmp, &sess->cr_active_list, cr_list) {
134	list_del(&cr->cr_list);
135	spin_unlock(&sess->cr_a_lock);
136
137	spin_lock(&cr->conn_recovery_cmd_lock);
138	list_for_each_entry_safe(cmd, cmd_tmp,
2fbb471e	139	&cr->conn_recovery_cmd_list, i_conn_node) {
e48354ce	140
5159d763	141	list_del_init(&cmd->i_conn_node);
e48354ce NB	142	cmd->conn = NULL;
e48354ce NB	143	spin_unlock(&cr->conn_recovery_cmd_lock);
aafc9d15	144	iscsit_free_cmd(cmd, true);
e48354ce NB	145	spin_lock(&cr->conn_recovery_cmd_lock);
	146	}
	147	spin_unlock(&cr->conn_recovery_cmd_lock);
	148	spin_lock(&sess->cr_a_lock);
	149
	150	kfree(cr);
	151	}
	152	spin_unlock(&sess->cr_a_lock);
	153
	154	spin_lock(&sess->cr_i_lock);
	155	list_for_each_entry_safe(cr, cr_tmp, &sess->cr_inactive_list, cr_list) {
	156	list_del(&cr->cr_list);
	157	spin_unlock(&sess->cr_i_lock);
	158
	159	spin_lock(&cr->conn_recovery_cmd_lock);
	160	list_for_each_entry_safe(cmd, cmd_tmp,
2fbb471e	161	&cr->conn_recovery_cmd_list, i_conn_node) {
e48354ce	162
5159d763	163	list_del_init(&cmd->i_conn_node);
e48354ce NB	164	cmd->conn = NULL;
e48354ce NB	165	spin_unlock(&cr->conn_recovery_cmd_lock);
aafc9d15	166	iscsit_free_cmd(cmd, true);
e48354ce NB	167	spin_lock(&cr->conn_recovery_cmd_lock);
	168	}
	169	spin_unlock(&cr->conn_recovery_cmd_lock);
	170	spin_lock(&sess->cr_i_lock);
	171
	172	kfree(cr);
	173	}
	174	spin_unlock(&sess->cr_i_lock);
	175	}
	176
	177	int iscsit_remove_active_connection_recovery_entry(
	178	struct iscsi_conn_recovery *cr,
	179	struct iscsi_session *sess)
	180	{
	181	spin_lock(&sess->cr_a_lock);
	182	list_del(&cr->cr_list);
	183
	184	sess->conn_recovery_count--;
	185	pr_debug("Decremented connection recovery count to %u for"
	186	" SID: %u\n", sess->conn_recovery_count, sess->sid);
	187	spin_unlock(&sess->cr_a_lock);
	188
	189	kfree(cr);
	190
	191	return 0;
	192	}
	193
fceb5bc7	194	static void iscsit_remove_inactive_connection_recovery_entry(
e48354ce NB	195	struct iscsi_conn_recovery *cr,
	196	struct iscsi_session *sess)
	197	{
	198	spin_lock(&sess->cr_i_lock);
	199	list_del(&cr->cr_list);
	200	spin_unlock(&sess->cr_i_lock);
e48354ce NB	201	}
	202
	203	/*
	204	* Called with cr->conn_recovery_cmd_lock help.
	205	*/
	206	int iscsit_remove_cmd_from_connection_recovery(
	207	struct iscsi_cmd *cmd,
	208	struct iscsi_session *sess)
	209	{
	210	struct iscsi_conn_recovery *cr;
	211
	212	if (!cmd->cr) {
	213	pr_err("struct iscsi_conn_recovery pointer for ITT: 0x%08x"
	214	" is NULL!\n", cmd->init_task_tag);
	215	BUG();
	216	}
	217	cr = cmd->cr;
	218
5159d763	219	list_del_init(&cmd->i_conn_node);
e48354ce NB	220	return --cr->cmd_count;
	221	}
	222
	223	void iscsit_discard_cr_cmds_by_expstatsn(
	224	struct iscsi_conn_recovery *cr,
	225	u32 exp_statsn)
	226	{
	227	u32 dropped_count = 0;
	228	struct iscsi_cmd cmd, cmd_tmp;
	229	struct iscsi_session *sess = cr->sess;
	230
	231	spin_lock(&cr->conn_recovery_cmd_lock);
	232	list_for_each_entry_safe(cmd, cmd_tmp,
2fbb471e	233	&cr->conn_recovery_cmd_list, i_conn_node) {
e48354ce NB	234
	235	if (((cmd->deferred_i_state != ISTATE_SENT_STATUS) &&
	236	(cmd->deferred_i_state != ISTATE_REMOVE)) \|\|
	237	(cmd->stat_sn >= exp_statsn)) {
	238	continue;
	239	}
	240
	241	dropped_count++;
	242	pr_debug("Dropping Acknowledged ITT: 0x%08x, StatSN:"
	243	" 0x%08x, CID: %hu.\n", cmd->init_task_tag,
	244	cmd->stat_sn, cr->cid);
	245
	246	iscsit_remove_cmd_from_connection_recovery(cmd, sess);
	247
	248	spin_unlock(&cr->conn_recovery_cmd_lock);
aafc9d15	249	iscsit_free_cmd(cmd, true);
e48354ce NB	250	spin_lock(&cr->conn_recovery_cmd_lock);
	251	}
	252	spin_unlock(&cr->conn_recovery_cmd_lock);
	253
	254	pr_debug("Dropped %u total acknowledged commands on"
	255	" CID: %hu less than old ExpStatSN: 0x%08x\n",
	256	dropped_count, cr->cid, exp_statsn);
	257
	258	if (!cr->cmd_count) {
	259	pr_debug("No commands to be reassigned for failed"
	260	" connection CID: %hu on SID: %u\n",
	261	cr->cid, sess->sid);
	262	iscsit_remove_inactive_connection_recovery_entry(cr, sess);
	263	iscsit_attach_active_connection_recovery_entry(sess, cr);
	264	pr_debug("iSCSI connection recovery successful for CID:"
	265	" %hu on SID: %u\n", cr->cid, sess->sid);
	266	iscsit_remove_active_connection_recovery_entry(cr, sess);
	267	} else {
	268	iscsit_remove_inactive_connection_recovery_entry(cr, sess);
	269	iscsit_attach_active_connection_recovery_entry(sess, cr);
	270	}
	271	}
	272
	273	int iscsit_discard_unacknowledged_ooo_cmdsns_for_conn(struct iscsi_conn *conn)
	274	{
	275	u32 dropped_count = 0;
	276	struct iscsi_cmd cmd, cmd_tmp;
	277	struct iscsi_ooo_cmdsn ooo_cmdsn, ooo_cmdsn_tmp;
	278	struct iscsi_session *sess = conn->sess;
	279
	280	mutex_lock(&sess->cmdsn_mutex);
	281	list_for_each_entry_safe(ooo_cmdsn, ooo_cmdsn_tmp,
	282	&sess->sess_ooo_cmdsn_list, ooo_list) {
	283
	284	if (ooo_cmdsn->cid != conn->cid)
	285	continue;
	286
	287	dropped_count++;
	288	pr_debug("Dropping unacknowledged CmdSN:"
	289	" 0x%08x during connection recovery on CID: %hu\n",
	290	ooo_cmdsn->cmdsn, conn->cid);
	291	iscsit_remove_ooo_cmdsn(sess, ooo_cmdsn);
	292	}
	293	mutex_unlock(&sess->cmdsn_mutex);
	294
	295	spin_lock_bh(&conn->cmd_lock);
2fbb471e	296	list_for_each_entry_safe(cmd, cmd_tmp, &conn->conn_cmd_list, i_conn_node) {
e48354ce NB	297	if (!(cmd->cmd_flags & ICF_OOO_CMDSN))
	298	continue;
	299
5159d763	300	list_del_init(&cmd->i_conn_node);
e48354ce NB	301
e48354ce NB	302	spin_unlock_bh(&conn->cmd_lock);
aafc9d15	303	iscsit_free_cmd(cmd, true);
e48354ce NB	304	spin_lock_bh(&conn->cmd_lock);
	305	}
	306	spin_unlock_bh(&conn->cmd_lock);
	307
	308	pr_debug("Dropped %u total unacknowledged commands on CID:"
	309	" %hu for ExpCmdSN: 0x%08x.\n", dropped_count, conn->cid,
	310	sess->exp_cmd_sn);
	311	return 0;
	312	}
	313
	314	int iscsit_prepare_cmds_for_realligance(struct iscsi_conn *conn)
	315	{
	316	u32 cmd_count = 0;
	317	struct iscsi_cmd cmd, cmd_tmp;
	318	struct iscsi_conn_recovery *cr;
	319
	320	/*
	321	* Allocate an struct iscsi_conn_recovery for this connection.
	322	* Each struct iscsi_cmd contains an struct iscsi_conn_recovery pointer
	323	* (struct iscsi_cmd->cr) so we need to allocate this before preparing the
	324	* connection's command list for connection recovery.
	325	*/
	326	cr = kzalloc(sizeof(struct iscsi_conn_recovery), GFP_KERNEL);
	327	if (!cr) {
	328	pr_err("Unable to allocate memory for"
	329	" struct iscsi_conn_recovery.\n");
	330	return -1;
	331	}
	332	INIT_LIST_HEAD(&cr->cr_list);
	333	INIT_LIST_HEAD(&cr->conn_recovery_cmd_list);
	334	spin_lock_init(&cr->conn_recovery_cmd_lock);
	335	/*
	336	* Only perform connection recovery on ISCSI_OP_SCSI_CMD or
	337	* ISCSI_OP_NOOP_OUT opcodes. For all other opcodes call
5159d763	338	* list_del_init(&cmd->i_conn_node); to release the command to the
e48354ce NB	339	* session pool and remove it from the connection's list.
	340	*
	341	* Also stop the DataOUT timer, which will be restarted after
	342	* sending the TMR response.
	343	*/
	344	spin_lock_bh(&conn->cmd_lock);
2fbb471e	345	list_for_each_entry_safe(cmd, cmd_tmp, &conn->conn_cmd_list, i_conn_node) {
e48354ce NB	346
	347	if ((cmd->iscsi_opcode != ISCSI_OP_SCSI_CMD) &&
	348	(cmd->iscsi_opcode != ISCSI_OP_NOOP_OUT)) {
	349	pr_debug("Not performing realligence on"
	350	" Opcode: 0x%02x, ITT: 0x%08x, CmdSN: 0x%08x,"
	351	" CID: %hu\n", cmd->iscsi_opcode,
	352	cmd->init_task_tag, cmd->cmd_sn, conn->cid);
	353
5159d763	354	list_del_init(&cmd->i_conn_node);
e48354ce	355	spin_unlock_bh(&conn->cmd_lock);
aafc9d15	356	iscsit_free_cmd(cmd, true);
e48354ce NB	357	spin_lock_bh(&conn->cmd_lock);
	358	continue;
	359	}
	360
	361	/*
	362	* Special case where commands greater than or equal to
	363	* the session's ExpCmdSN are attached to the connection
	364	* list but not to the out of order CmdSN list. The one
	365	* obvious case is when a command with immediate data
	366	* attached must only check the CmdSN against ExpCmdSN
	367	* after the data is received. The special case below
	368	* is when the connection fails before data is received,
	369	* but also may apply to other PDUs, so it has been
	370	* made generic here.
	371	*/
	372	if (!(cmd->cmd_flags & ICF_OOO_CMDSN) && !cmd->immediate_cmd &&
64fe4f4f	373	iscsi_sna_gte(cmd->cmd_sn, conn->sess->exp_cmd_sn)) {
5159d763	374	list_del_init(&cmd->i_conn_node);
e48354ce	375	spin_unlock_bh(&conn->cmd_lock);
aafc9d15	376	iscsit_free_cmd(cmd, true);
e48354ce NB	377	spin_lock_bh(&conn->cmd_lock);
	378	continue;
	379	}
	380
	381	cmd_count++;
	382	pr_debug("Preparing Opcode: 0x%02x, ITT: 0x%08x,"
	383	" CmdSN: 0x%08x, StatSN: 0x%08x, CID: %hu for"
	384	" realligence.\n", cmd->iscsi_opcode,
	385	cmd->init_task_tag, cmd->cmd_sn, cmd->stat_sn,
	386	conn->cid);
	387
	388	cmd->deferred_i_state = cmd->i_state;
	389	cmd->i_state = ISTATE_IN_CONNECTION_RECOVERY;
	390
	391	if (cmd->data_direction == DMA_TO_DEVICE)
	392	iscsit_stop_dataout_timer(cmd);
	393
	394	cmd->sess = conn->sess;
	395
5159d763	396	list_del_init(&cmd->i_conn_node);
e48354ce NB	397	spin_unlock_bh(&conn->cmd_lock);
	398
	399	iscsit_free_all_datain_reqs(cmd);
	400
d270190a	401	transport_wait_for_tasks(&cmd->se_cmd);
e48354ce NB	402	/*
	403	* Add the struct iscsi_cmd to the connection recovery cmd list
	404	*/
	405	spin_lock(&cr->conn_recovery_cmd_lock);
2fbb471e	406	list_add_tail(&cmd->i_conn_node, &cr->conn_recovery_cmd_list);
e48354ce NB	407	spin_unlock(&cr->conn_recovery_cmd_lock);
	408
	409	spin_lock_bh(&conn->cmd_lock);
	410	cmd->cr = cr;
	411	cmd->conn = NULL;
	412	}
	413	spin_unlock_bh(&conn->cmd_lock);
	414	/*
	415	* Fill in the various values in the preallocated struct iscsi_conn_recovery.
	416	*/
	417	cr->cid = conn->cid;
	418	cr->cmd_count = cmd_count;
	419	cr->maxrecvdatasegmentlength = conn->conn_ops->MaxRecvDataSegmentLength;
1c417f39	420	cr->maxxmitdatasegmentlength = conn->conn_ops->MaxXmitDataSegmentLength;
e48354ce NB	421	cr->sess = conn->sess;
	422
	423	iscsit_attach_inactive_connection_recovery_entry(conn->sess, cr);
	424
	425	return 0;
	426	}
	427
	428	int iscsit_connection_recovery_transport_reset(struct iscsi_conn *conn)
	429	{
	430	atomic_set(&conn->connection_recovery, 1);
	431
	432	if (iscsit_close_connection(conn) < 0)
	433	return -1;
	434
	435	return 0;
	436	}