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

/*******************************************************************************
 * This file contains error recovery level two 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_fabric.h>

#include "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,
	u32 exp_data_sn)
{
	u32 data_sn = 0;
	struct iscsi_conn *conn = cmd->conn;

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

	while (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_list) {

			list_del(&cmd->i_list);
			cmd->conn = NULL;
			spin_unlock(&cr->conn_recovery_cmd_lock);
			iscsit_free_cmd(cmd);
			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_list) {

			list_del(&cmd->i_list);
			cmd->conn = NULL;
			spin_unlock(&cr->conn_recovery_cmd_lock);
			iscsit_free_cmd(cmd);
			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;
}

int 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);

	return 0;
}

/*
 *	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(&cmd->i_list);
	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_list) {

		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);
		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_list) {
		if (!(cmd->cmd_flags & ICF_OOO_CMDSN))
			continue;

		list_del(&cmd->i_list);

		spin_unlock_bh(&conn->cmd_lock);
		iscsit_free_cmd(cmd);
		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(&cmd->i_list); 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_list) {

		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(&cmd->i_list);
			spin_unlock_bh(&conn->cmd_lock);
			iscsit_free_cmd(cmd);
			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 &&
		     (cmd->cmd_sn >= conn->sess->exp_cmd_sn)) {
			list_del(&cmd->i_list);
			spin_unlock_bh(&conn->cmd_lock);
			iscsit_free_cmd(cmd);
			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(&cmd->i_list);
		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_list, &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->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	*
	5	* \u00a9 Copyright 2007-2011 RisingTide Systems LLC.
	6	*
	7	* Licensed to the Linux Foundation under the General Public License (GPL) version 2.
	8	*
	9	* Author: Nicholas A. Bellinger <nab@linux-iscsi.org>
	10	*
	11	* This program is free software; you can redistribute it and/or modify
	12	* it under the terms of the GNU General Public License as published by
	13	* the Free Software Foundation; either version 2 of the License, or
	14	* (at your option) any later version.
	15	*
	16	* This program is distributed in the hope that it will be useful,
	17	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	18	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	19	* GNU General Public License for more details.
	20	******************************************************************************/
	21
	22	#include <scsi/iscsi_proto.h>
	23	#include <target/target_core_base.h>
c4795fb2	24	#include <target/target_core_fabric.h>
e48354ce NB	25
	26	#include "iscsi_target_core.h"
	27	#include "iscsi_target_datain_values.h"
	28	#include "iscsi_target_util.h"
	29	#include "iscsi_target_erl0.h"
	30	#include "iscsi_target_erl1.h"
	31	#include "iscsi_target_erl2.h"
	32	#include "iscsi_target.h"
	33
	34	/*
	35	* FIXME: Does RData SNACK apply here as well?
	36	*/
	37	void iscsit_create_conn_recovery_datain_values(
	38	struct iscsi_cmd *cmd,
	39	u32 exp_data_sn)
	40	{
	41	u32 data_sn = 0;
	42	struct iscsi_conn *conn = cmd->conn;
	43
	44	cmd->next_burst_len = 0;
	45	cmd->read_data_done = 0;
	46
	47	while (exp_data_sn > data_sn) {
	48	if ((cmd->next_burst_len +
	49	conn->conn_ops->MaxRecvDataSegmentLength) <
	50	conn->sess->sess_ops->MaxBurstLength) {
	51	cmd->read_data_done +=
	52	conn->conn_ops->MaxRecvDataSegmentLength;
	53	cmd->next_burst_len +=
	54	conn->conn_ops->MaxRecvDataSegmentLength;
	55	} else {
	56	cmd->read_data_done +=
	57	(conn->sess->sess_ops->MaxBurstLength -
	58	cmd->next_burst_len);
	59	cmd->next_burst_len = 0;
	60	}
	61	data_sn++;
	62	}
	63	}
	64
	65	void iscsit_create_conn_recovery_dataout_values(
	66	struct iscsi_cmd *cmd)
	67	{
	68	u32 write_data_done = 0;
	69	struct iscsi_conn *conn = cmd->conn;
	70
	71	cmd->data_sn = 0;
	72	cmd->next_burst_len = 0;
	73
	74	while (cmd->write_data_done > write_data_done) {
	75	if ((write_data_done + conn->sess->sess_ops->MaxBurstLength) <=
	76	cmd->write_data_done)
	77	write_data_done += conn->sess->sess_ops->MaxBurstLength;
	78	else
	79	break;
	80	}
	81
	82	cmd->write_data_done = write_data_done;
	83	}
	84
	85	static int iscsit_attach_active_connection_recovery_entry(
	86	struct iscsi_session *sess,
	87	struct iscsi_conn_recovery *cr)
	88	{
89	spin_lock(&sess->cr_a_lock);
90	list_add_tail(&cr->cr_list, &sess->cr_active_list);
91	spin_unlock(&sess->cr_a_lock);
92
93	return 0;
94	}
95
96	static int iscsit_attach_inactive_connection_recovery_entry(
97	struct iscsi_session *sess,
98	struct iscsi_conn_recovery *cr)
99	{
100	spin_lock(&sess->cr_i_lock);
101	list_add_tail(&cr->cr_list, &sess->cr_inactive_list);
102
103	sess->conn_recovery_count++;
104	pr_debug("Incremented connection recovery count to %u for"
105	" SID: %u\n", sess->conn_recovery_count, sess->sid);
106	spin_unlock(&sess->cr_i_lock);
107
108	return 0;
109	}
110
111	struct iscsi_conn_recovery *iscsit_get_inactive_connection_recovery_entry(
112	struct iscsi_session *sess,
113	u16 cid)
114	{
115	struct iscsi_conn_recovery *cr;
116
117	spin_lock(&sess->cr_i_lock);
118	list_for_each_entry(cr, &sess->cr_inactive_list, cr_list) {
119	if (cr->cid == cid) {
120	spin_unlock(&sess->cr_i_lock);
121	return cr;
122	}
123	}
124	spin_unlock(&sess->cr_i_lock);
125
126	return NULL;
127	}
128
129	void iscsit_free_connection_recovery_entires(struct iscsi_session *sess)
130	{
131	struct iscsi_cmd cmd, cmd_tmp;
132	struct iscsi_conn_recovery cr, cr_tmp;
133
134	spin_lock(&sess->cr_a_lock);
135	list_for_each_entry_safe(cr, cr_tmp, &sess->cr_active_list, cr_list) {
136	list_del(&cr->cr_list);
137	spin_unlock(&sess->cr_a_lock);
138
139	spin_lock(&cr->conn_recovery_cmd_lock);
140	list_for_each_entry_safe(cmd, cmd_tmp,
141	&cr->conn_recovery_cmd_list, i_list) {
142
143	list_del(&cmd->i_list);
144	cmd->conn = NULL;
145	spin_unlock(&cr->conn_recovery_cmd_lock);
d270190a	146	iscsit_free_cmd(cmd);
e48354ce NB	147	spin_lock(&cr->conn_recovery_cmd_lock);
	148	}
	149	spin_unlock(&cr->conn_recovery_cmd_lock);
	150	spin_lock(&sess->cr_a_lock);
	151
	152	kfree(cr);
	153	}
	154	spin_unlock(&sess->cr_a_lock);
	155
	156	spin_lock(&sess->cr_i_lock);
	157	list_for_each_entry_safe(cr, cr_tmp, &sess->cr_inactive_list, cr_list) {
	158	list_del(&cr->cr_list);
	159	spin_unlock(&sess->cr_i_lock);
	160
	161	spin_lock(&cr->conn_recovery_cmd_lock);
	162	list_for_each_entry_safe(cmd, cmd_tmp,
	163	&cr->conn_recovery_cmd_list, i_list) {
	164
	165	list_del(&cmd->i_list);
	166	cmd->conn = NULL;
	167	spin_unlock(&cr->conn_recovery_cmd_lock);
d270190a	168	iscsit_free_cmd(cmd);
e48354ce NB	169	spin_lock(&cr->conn_recovery_cmd_lock);
	170	}
	171	spin_unlock(&cr->conn_recovery_cmd_lock);
	172	spin_lock(&sess->cr_i_lock);
	173
	174	kfree(cr);
	175	}
	176	spin_unlock(&sess->cr_i_lock);
	177	}
	178
	179	int iscsit_remove_active_connection_recovery_entry(
	180	struct iscsi_conn_recovery *cr,
	181	struct iscsi_session *sess)
	182	{
	183	spin_lock(&sess->cr_a_lock);
	184	list_del(&cr->cr_list);
	185
	186	sess->conn_recovery_count--;
	187	pr_debug("Decremented connection recovery count to %u for"
	188	" SID: %u\n", sess->conn_recovery_count, sess->sid);
	189	spin_unlock(&sess->cr_a_lock);
	190
	191	kfree(cr);
	192
	193	return 0;
	194	}
	195
	196	int iscsit_remove_inactive_connection_recovery_entry(
	197	struct iscsi_conn_recovery *cr,
	198	struct iscsi_session *sess)
	199	{
	200	spin_lock(&sess->cr_i_lock);
	201	list_del(&cr->cr_list);
	202	spin_unlock(&sess->cr_i_lock);
	203
	204	return 0;
	205	}
	206
	207	/*
	208	* Called with cr->conn_recovery_cmd_lock help.
	209	*/
	210	int iscsit_remove_cmd_from_connection_recovery(
	211	struct iscsi_cmd *cmd,
	212	struct iscsi_session *sess)
	213	{
	214	struct iscsi_conn_recovery *cr;
	215
	216	if (!cmd->cr) {
	217	pr_err("struct iscsi_conn_recovery pointer for ITT: 0x%08x"
	218	" is NULL!\n", cmd->init_task_tag);
	219	BUG();
	220	}
	221	cr = cmd->cr;
	222
	223	list_del(&cmd->i_list);
	224	return --cr->cmd_count;
	225	}
	226
	227	void iscsit_discard_cr_cmds_by_expstatsn(
	228	struct iscsi_conn_recovery *cr,
	229	u32 exp_statsn)
	230	{
	231	u32 dropped_count = 0;
	232	struct iscsi_cmd cmd, cmd_tmp;
233	struct iscsi_session *sess = cr->sess;
234
235	spin_lock(&cr->conn_recovery_cmd_lock);
236	list_for_each_entry_safe(cmd, cmd_tmp,
237	&cr->conn_recovery_cmd_list, i_list) {
238
239	if (((cmd->deferred_i_state != ISTATE_SENT_STATUS) &&
240	(cmd->deferred_i_state != ISTATE_REMOVE)) \|\|
241	(cmd->stat_sn >= exp_statsn)) {
242	continue;
243	}
244
245	dropped_count++;
246	pr_debug("Dropping Acknowledged ITT: 0x%08x, StatSN:"
247	" 0x%08x, CID: %hu.\n", cmd->init_task_tag,
248	cmd->stat_sn, cr->cid);
249
250	iscsit_remove_cmd_from_connection_recovery(cmd, sess);
251
252	spin_unlock(&cr->conn_recovery_cmd_lock);
d270190a	253	iscsit_free_cmd(cmd);
e48354ce NB	254	spin_lock(&cr->conn_recovery_cmd_lock);
	255	}
	256	spin_unlock(&cr->conn_recovery_cmd_lock);
	257
	258	pr_debug("Dropped %u total acknowledged commands on"
	259	" CID: %hu less than old ExpStatSN: 0x%08x\n",
	260	dropped_count, cr->cid, exp_statsn);
	261
	262	if (!cr->cmd_count) {
	263	pr_debug("No commands to be reassigned for failed"
	264	" connection CID: %hu on SID: %u\n",
	265	cr->cid, sess->sid);
	266	iscsit_remove_inactive_connection_recovery_entry(cr, sess);
	267	iscsit_attach_active_connection_recovery_entry(sess, cr);
	268	pr_debug("iSCSI connection recovery successful for CID:"
	269	" %hu on SID: %u\n", cr->cid, sess->sid);
	270	iscsit_remove_active_connection_recovery_entry(cr, sess);
	271	} else {
	272	iscsit_remove_inactive_connection_recovery_entry(cr, sess);
	273	iscsit_attach_active_connection_recovery_entry(sess, cr);
	274	}
	275	}
	276
	277	int iscsit_discard_unacknowledged_ooo_cmdsns_for_conn(struct iscsi_conn *conn)
	278	{
	279	u32 dropped_count = 0;
	280	struct iscsi_cmd cmd, cmd_tmp;
	281	struct iscsi_ooo_cmdsn ooo_cmdsn, ooo_cmdsn_tmp;
	282	struct iscsi_session *sess = conn->sess;
	283
	284	mutex_lock(&sess->cmdsn_mutex);
	285	list_for_each_entry_safe(ooo_cmdsn, ooo_cmdsn_tmp,
	286	&sess->sess_ooo_cmdsn_list, ooo_list) {
	287
	288	if (ooo_cmdsn->cid != conn->cid)
	289	continue;
	290
	291	dropped_count++;
	292	pr_debug("Dropping unacknowledged CmdSN:"
	293	" 0x%08x during connection recovery on CID: %hu\n",
	294	ooo_cmdsn->cmdsn, conn->cid);
	295	iscsit_remove_ooo_cmdsn(sess, ooo_cmdsn);
	296	}
	297	mutex_unlock(&sess->cmdsn_mutex);
	298
	299	spin_lock_bh(&conn->cmd_lock);
	300	list_for_each_entry_safe(cmd, cmd_tmp, &conn->conn_cmd_list, i_list) {
	301	if (!(cmd->cmd_flags & ICF_OOO_CMDSN))
	302	continue;
	303
	304	list_del(&cmd->i_list);
	305
	306	spin_unlock_bh(&conn->cmd_lock);
d270190a	307	iscsit_free_cmd(cmd);
e48354ce NB	308	spin_lock_bh(&conn->cmd_lock);
	309	}
	310	spin_unlock_bh(&conn->cmd_lock);
	311
	312	pr_debug("Dropped %u total unacknowledged commands on CID:"
	313	" %hu for ExpCmdSN: 0x%08x.\n", dropped_count, conn->cid,
	314	sess->exp_cmd_sn);
	315	return 0;
	316	}
	317
	318	int iscsit_prepare_cmds_for_realligance(struct iscsi_conn *conn)
	319	{
	320	u32 cmd_count = 0;
	321	struct iscsi_cmd cmd, cmd_tmp;
	322	struct iscsi_conn_recovery *cr;
	323
	324	/*
	325	* Allocate an struct iscsi_conn_recovery for this connection.
	326	* Each struct iscsi_cmd contains an struct iscsi_conn_recovery pointer
	327	* (struct iscsi_cmd->cr) so we need to allocate this before preparing the
	328	* connection's command list for connection recovery.
	329	*/
	330	cr = kzalloc(sizeof(struct iscsi_conn_recovery), GFP_KERNEL);
	331	if (!cr) {
	332	pr_err("Unable to allocate memory for"
	333	" struct iscsi_conn_recovery.\n");
	334	return -1;
	335	}
	336	INIT_LIST_HEAD(&cr->cr_list);
	337	INIT_LIST_HEAD(&cr->conn_recovery_cmd_list);
	338	spin_lock_init(&cr->conn_recovery_cmd_lock);
	339	/*
	340	* Only perform connection recovery on ISCSI_OP_SCSI_CMD or
	341	* ISCSI_OP_NOOP_OUT opcodes. For all other opcodes call
	342	* list_del(&cmd->i_list); to release the command to the
	343	* session pool and remove it from the connection's list.
	344	*
	345	* Also stop the DataOUT timer, which will be restarted after
	346	* sending the TMR response.
	347	*/
	348	spin_lock_bh(&conn->cmd_lock);
	349	list_for_each_entry_safe(cmd, cmd_tmp, &conn->conn_cmd_list, i_list) {
	350
	351	if ((cmd->iscsi_opcode != ISCSI_OP_SCSI_CMD) &&
	352	(cmd->iscsi_opcode != ISCSI_OP_NOOP_OUT)) {
	353	pr_debug("Not performing realligence on"
	354	" Opcode: 0x%02x, ITT: 0x%08x, CmdSN: 0x%08x,"
	355	" CID: %hu\n", cmd->iscsi_opcode,
	356	cmd->init_task_tag, cmd->cmd_sn, conn->cid);
	357
	358	list_del(&cmd->i_list);
	359	spin_unlock_bh(&conn->cmd_lock);
d270190a	360	iscsit_free_cmd(cmd);
e48354ce NB	361	spin_lock_bh(&conn->cmd_lock);
	362	continue;
	363	}
	364
	365	/*
	366	* Special case where commands greater than or equal to
	367	* the session's ExpCmdSN are attached to the connection
	368	* list but not to the out of order CmdSN list. The one
	369	* obvious case is when a command with immediate data
	370	* attached must only check the CmdSN against ExpCmdSN
	371	* after the data is received. The special case below
	372	* is when the connection fails before data is received,
	373	* but also may apply to other PDUs, so it has been
	374	* made generic here.
	375	*/
	376	if (!(cmd->cmd_flags & ICF_OOO_CMDSN) && !cmd->immediate_cmd &&
	377	(cmd->cmd_sn >= conn->sess->exp_cmd_sn)) {
	378	list_del(&cmd->i_list);
	379	spin_unlock_bh(&conn->cmd_lock);
d270190a	380	iscsit_free_cmd(cmd);
e48354ce NB	381	spin_lock_bh(&conn->cmd_lock);
	382	continue;
	383	}
	384
	385	cmd_count++;
	386	pr_debug("Preparing Opcode: 0x%02x, ITT: 0x%08x,"
	387	" CmdSN: 0x%08x, StatSN: 0x%08x, CID: %hu for"
	388	" realligence.\n", cmd->iscsi_opcode,
	389	cmd->init_task_tag, cmd->cmd_sn, cmd->stat_sn,
	390	conn->cid);
	391
	392	cmd->deferred_i_state = cmd->i_state;
	393	cmd->i_state = ISTATE_IN_CONNECTION_RECOVERY;
	394
	395	if (cmd->data_direction == DMA_TO_DEVICE)
	396	iscsit_stop_dataout_timer(cmd);
	397
	398	cmd->sess = conn->sess;
	399
	400	list_del(&cmd->i_list);
	401	spin_unlock_bh(&conn->cmd_lock);
	402
	403	iscsit_free_all_datain_reqs(cmd);
	404
d270190a	405	transport_wait_for_tasks(&cmd->se_cmd);
e48354ce NB	406	/*
	407	* Add the struct iscsi_cmd to the connection recovery cmd list
	408	*/
	409	spin_lock(&cr->conn_recovery_cmd_lock);
	410	list_add_tail(&cmd->i_list, &cr->conn_recovery_cmd_list);
	411	spin_unlock(&cr->conn_recovery_cmd_lock);
	412
	413	spin_lock_bh(&conn->cmd_lock);
	414	cmd->cr = cr;
	415	cmd->conn = NULL;
	416	}
	417	spin_unlock_bh(&conn->cmd_lock);
	418	/*
	419	* Fill in the various values in the preallocated struct iscsi_conn_recovery.
	420	*/
	421	cr->cid = conn->cid;
	422	cr->cmd_count = cmd_count;
	423	cr->maxrecvdatasegmentlength = conn->conn_ops->MaxRecvDataSegmentLength;
	424	cr->sess = conn->sess;
	425
	426	iscsit_attach_inactive_connection_recovery_entry(conn->sess, cr);
	427
	428	return 0;
	429	}
	430
	431	int iscsit_connection_recovery_transport_reset(struct iscsi_conn *conn)
	432	{
	433	atomic_set(&conn->connection_recovery, 1);
	434
	435	if (iscsit_close_connection(conn) < 0)
	436	return -1;
	437
	438	return 0;
	439	}