LXR linux/drivers/target/iscsi/iscsi_target

   1/*******************************************************************************
   2 * This file contains error recovery level two functions used by
   3 * the iSCSI Target driver.
   4 *
   5 * (c) Copyright 2007-2013 Datera, Inc.
   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 <linux/slab.h>
  21#include <scsi/iscsi_proto.h>
  22#include <target/target_core_base.h>
  23#include <target/target_core_fabric.h>
  24
  25#include <target/iscsi/iscsi_target_core.h>
  26#include "iscsi_target_datain_values.h"
  27#include "iscsi_target_util.h"
  28#include "iscsi_target_erl0.h"
  29#include "iscsi_target_erl1.h"
  30#include "iscsi_target_erl2.h"
  31#include "iscsi_target.h"
  32
  33/*
  34 *      FIXME: Does RData SNACK apply here as well?
  35 */
  36void iscsit_create_conn_recovery_datain_values(
  37        struct iscsi_cmd *cmd,
  38        __be32 exp_data_sn)
  39{
  40        u32 data_sn = 0;
  41        struct iscsi_conn *conn = cmd->conn;
  42
  43        cmd->next_burst_len = 0;
  44        cmd->read_data_done = 0;
  45
  46        while (be32_to_cpu(exp_data_sn) > data_sn) {
  47                if ((cmd->next_burst_len +
  48                     conn->conn_ops->MaxRecvDataSegmentLength) <
  49                     conn->sess->sess_ops->MaxBurstLength) {
  50                        cmd->read_data_done +=
  51                               conn->conn_ops->MaxRecvDataSegmentLength;
  52                        cmd->next_burst_len +=
  53                               conn->conn_ops->MaxRecvDataSegmentLength;
  54                } else {
  55                        cmd->read_data_done +=
  56                                (conn->sess->sess_ops->MaxBurstLength -
  57                                cmd->next_burst_len);
  58                        cmd->next_burst_len = 0;
  59                }
  60                data_sn++;
  61        }
  62}
  63
  64void iscsit_create_conn_recovery_dataout_values(
  65        struct iscsi_cmd *cmd)
  66{
  67        u32 write_data_done = 0;
  68        struct iscsi_conn *conn = cmd->conn;
  69
  70        cmd->data_sn = 0;
  71        cmd->next_burst_len = 0;
  72
  73        while (cmd->write_data_done > write_data_done) {
  74                if ((write_data_done + conn->sess->sess_ops->MaxBurstLength) <=
  75                     cmd->write_data_done)
  76                        write_data_done += conn->sess->sess_ops->MaxBurstLength;
  77                else
  78                        break;
  79        }
  80
  81        cmd->write_data_done = write_data_done;
  82}
  83
  84static int iscsit_attach_active_connection_recovery_entry(
  85        struct iscsi_session *sess,
  86        struct iscsi_conn_recovery *cr)
  87{
  88        spin_lock(&sess->cr_a_lock);
  89        list_add_tail(&cr->cr_list, &sess->cr_active_list);
  90        spin_unlock(&sess->cr_a_lock);
  91
  92        return 0;
  93}
  94
  95static int iscsit_attach_inactive_connection_recovery_entry(
  96        struct iscsi_session *sess,
  97        struct iscsi_conn_recovery *cr)
  98{
  99        spin_lock(&sess->cr_i_lock);
 100        list_add_tail(&cr->cr_list, &sess->cr_inactive_list);
 101
 102        sess->conn_recovery_count++;
 103        pr_debug("Incremented connection recovery count to %u for"
 104                " SID: %u\n", sess->conn_recovery_count, sess->sid);
 105        spin_unlock(&sess->cr_i_lock);
 106
 107        return 0;
 108}
 109
 110struct iscsi_conn_recovery *iscsit_get_inactive_connection_recovery_entry(
 111        struct iscsi_session *sess,
 112        u16 cid)
 113{
 114        struct iscsi_conn_recovery *cr;
 115
 116        spin_lock(&sess->cr_i_lock);
 117        list_for_each_entry(cr, &sess->cr_inactive_list, cr_list) {
 118                if (cr->cid == cid) {
 119                        spin_unlock(&sess->cr_i_lock);
 120                        return cr;
 121                }
 122        }
 123        spin_unlock(&sess->cr_i_lock);
 124
 125        return NULL;
 126}
 127
 128void iscsit_free_connection_recovery_entries(struct iscsi_session *sess)
 129{
 130        struct iscsi_cmd *cmd, *cmd_tmp;
 131        struct iscsi_conn_recovery *cr, *cr_tmp;
 132
 133        spin_lock(&sess->cr_a_lock);
 134        list_for_each_entry_safe(cr, cr_tmp, &sess->cr_active_list, cr_list) {
 135                list_del(&cr->cr_list);
 136                spin_unlock(&sess->cr_a_lock);
 137
 138                spin_lock(&cr->conn_recovery_cmd_lock);
 139                list_for_each_entry_safe(cmd, cmd_tmp,
 140                                &cr->conn_recovery_cmd_list, i_conn_node) {
 141
 142                        list_del_init(&cmd->i_conn_node);
 143                        cmd->conn = NULL;
 144                        spin_unlock(&cr->conn_recovery_cmd_lock);
 145                        iscsit_free_cmd(cmd, true);
 146                        spin_lock(&cr->conn_recovery_cmd_lock);
 147                }
 148                spin_unlock(&cr->conn_recovery_cmd_lock);
 149                spin_lock(&sess->cr_a_lock);
 150
 151                kfree(cr);
 152        }
 153        spin_unlock(&sess->cr_a_lock);
 154
 155        spin_lock(&sess->cr_i_lock);
 156        list_for_each_entry_safe(cr, cr_tmp, &sess->cr_inactive_list, cr_list) {
 157                list_del(&cr->cr_list);
 158                spin_unlock(&sess->cr_i_lock);
 159
 160                spin_lock(&cr->conn_recovery_cmd_lock);
 161                list_for_each_entry_safe(cmd, cmd_tmp,
 162                                &cr->conn_recovery_cmd_list, i_conn_node) {
 163
 164                        list_del_init(&cmd->i_conn_node);
 165                        cmd->conn = NULL;
 166                        spin_unlock(&cr->conn_recovery_cmd_lock);
 167                        iscsit_free_cmd(cmd, true);
 168                        spin_lock(&cr->conn_recovery_cmd_lock);
 169                }
 170                spin_unlock(&cr->conn_recovery_cmd_lock);
 171                spin_lock(&sess->cr_i_lock);
 172
 173                kfree(cr);
 174        }
 175        spin_unlock(&sess->cr_i_lock);
 176}
 177
 178int iscsit_remove_active_connection_recovery_entry(
 179        struct iscsi_conn_recovery *cr,
 180        struct iscsi_session *sess)
 181{
 182        spin_lock(&sess->cr_a_lock);
 183        list_del(&cr->cr_list);
 184
 185        sess->conn_recovery_count--;
 186        pr_debug("Decremented connection recovery count to %u for"
 187                " SID: %u\n", sess->conn_recovery_count, sess->sid);
 188        spin_unlock(&sess->cr_a_lock);
 189
 190        kfree(cr);
 191
 192        return 0;
 193}
 194
 195static void iscsit_remove_inactive_connection_recovery_entry(
 196        struct iscsi_conn_recovery *cr,
 197        struct iscsi_session *sess)
 198{
 199        spin_lock(&sess->cr_i_lock);
 200        list_del(&cr->cr_list);
 201        spin_unlock(&sess->cr_i_lock);
 202}
 203
 204/*
 205 *      Called with cr->conn_recovery_cmd_lock help.
 206 */
 207int iscsit_remove_cmd_from_connection_recovery(
 208        struct iscsi_cmd *cmd,
 209        struct iscsi_session *sess)
 210{
 211        struct iscsi_conn_recovery *cr;
 212
 213        if (!cmd->cr) {
 214                pr_err("struct iscsi_conn_recovery pointer for ITT: 0x%08x"
 215                        " is NULL!\n", cmd->init_task_tag);
 216                BUG();
 217        }
 218        cr = cmd->cr;
 219
 220        list_del_init(&cmd->i_conn_node);
 221        return --cr->cmd_count;
 222}
 223
 224void iscsit_discard_cr_cmds_by_expstatsn(
 225        struct iscsi_conn_recovery *cr,
 226        u32 exp_statsn)
 227{
 228        u32 dropped_count = 0;
 229        struct iscsi_cmd *cmd, *cmd_tmp;
 230        struct iscsi_session *sess = cr->sess;
 231
 232        spin_lock(&cr->conn_recovery_cmd_lock);
 233        list_for_each_entry_safe(cmd, cmd_tmp,
 234                        &cr->conn_recovery_cmd_list, i_conn_node) {
 235
 236                if (((cmd->deferred_i_state != ISTATE_SENT_STATUS) &&
 237                     (cmd->deferred_i_state != ISTATE_REMOVE)) ||
 238                     (cmd->stat_sn >= exp_statsn)) {
 239                        continue;
 240                }
 241
 242                dropped_count++;
 243                pr_debug("Dropping Acknowledged ITT: 0x%08x, StatSN:"
 244                        " 0x%08x, CID: %hu.\n", cmd->init_task_tag,
 245                                cmd->stat_sn, cr->cid);
 246
 247                iscsit_remove_cmd_from_connection_recovery(cmd, sess);
 248
 249                spin_unlock(&cr->conn_recovery_cmd_lock);
 250                iscsit_free_cmd(cmd, true);
 251                spin_lock(&cr->conn_recovery_cmd_lock);
 252        }
 253        spin_unlock(&cr->conn_recovery_cmd_lock);
 254
 255        pr_debug("Dropped %u total acknowledged commands on"
 256                " CID: %hu less than old ExpStatSN: 0x%08x\n",
 257                        dropped_count, cr->cid, exp_statsn);
 258
 259        if (!cr->cmd_count) {
 260                pr_debug("No commands to be reassigned for failed"
 261                        " connection CID: %hu on SID: %u\n",
 262                        cr->cid, sess->sid);
 263                iscsit_remove_inactive_connection_recovery_entry(cr, sess);
 264                iscsit_attach_active_connection_recovery_entry(sess, cr);
 265                pr_debug("iSCSI connection recovery successful for CID:"
 266                        " %hu on SID: %u\n", cr->cid, sess->sid);
 267                iscsit_remove_active_connection_recovery_entry(cr, sess);
 268        } else {
 269                iscsit_remove_inactive_connection_recovery_entry(cr, sess);
 270                iscsit_attach_active_connection_recovery_entry(sess, cr);
 271        }
 272}
 273
 274int iscsit_discard_unacknowledged_ooo_cmdsns_for_conn(struct iscsi_conn *conn)
 275{
 276        u32 dropped_count = 0;
 277        struct iscsi_cmd *cmd, *cmd_tmp;
 278        struct iscsi_ooo_cmdsn *ooo_cmdsn, *ooo_cmdsn_tmp;
 279        struct iscsi_session *sess = conn->sess;
 280
 281        mutex_lock(&sess->cmdsn_mutex);
 282        list_for_each_entry_safe(ooo_cmdsn, ooo_cmdsn_tmp,
 283                        &sess->sess_ooo_cmdsn_list, ooo_list) {
 284
 285                if (ooo_cmdsn->cid != conn->cid)
 286                        continue;
 287
 288                dropped_count++;
 289                pr_debug("Dropping unacknowledged CmdSN:"
 290                " 0x%08x during connection recovery on CID: %hu\n",
 291                        ooo_cmdsn->cmdsn, conn->cid);
 292                iscsit_remove_ooo_cmdsn(sess, ooo_cmdsn);
 293        }
 294        mutex_unlock(&sess->cmdsn_mutex);
 295
 296        spin_lock_bh(&conn->cmd_lock);
 297        list_for_each_entry_safe(cmd, cmd_tmp, &conn->conn_cmd_list, i_conn_node) {
 298                if (!(cmd->cmd_flags & ICF_OOO_CMDSN))
 299                        continue;
 300
 301                list_del_init(&cmd->i_conn_node);
 302
 303                spin_unlock_bh(&conn->cmd_lock);
 304                iscsit_free_cmd(cmd, true);
 305                spin_lock_bh(&conn->cmd_lock);
 306        }
 307        spin_unlock_bh(&conn->cmd_lock);
 308
 309        pr_debug("Dropped %u total unacknowledged commands on CID:"
 310                " %hu for ExpCmdSN: 0x%08x.\n", dropped_count, conn->cid,
 311                                sess->exp_cmd_sn);
 312        return 0;
 313}
 314
 315int iscsit_prepare_cmds_for_reallegiance(struct iscsi_conn *conn)
 316{
 317        u32 cmd_count = 0;
 318        struct iscsi_cmd *cmd, *cmd_tmp;
 319        struct iscsi_conn_recovery *cr;
 320
 321        /*
 322         * Allocate an struct iscsi_conn_recovery for this connection.
 323         * Each struct iscsi_cmd contains an struct iscsi_conn_recovery pointer
 324         * (struct iscsi_cmd->cr) so we need to allocate this before preparing the
 325         * connection's command list for connection recovery.
 326         */
 327        cr = kzalloc(sizeof(struct iscsi_conn_recovery), GFP_KERNEL);
 328        if (!cr) {
 329                pr_err("Unable to allocate memory for"
 330                        " struct iscsi_conn_recovery.\n");
 331                return -1;
 332        }
 333        INIT_LIST_HEAD(&cr->cr_list);
 334        INIT_LIST_HEAD(&cr->conn_recovery_cmd_list);
 335        spin_lock_init(&cr->conn_recovery_cmd_lock);
 336        /*
 337         * Only perform connection recovery on ISCSI_OP_SCSI_CMD or
 338         * ISCSI_OP_NOOP_OUT opcodes.  For all other opcodes call
 339         * list_del_init(&cmd->i_conn_node); to release the command to the
 340         * session pool and remove it from the connection's list.
 341         *
 342         * Also stop the DataOUT timer, which will be restarted after
 343         * sending the TMR response.
 344         */
 345        spin_lock_bh(&conn->cmd_lock);
 346        list_for_each_entry_safe(cmd, cmd_tmp, &conn->conn_cmd_list, i_conn_node) {
 347
 348                if ((cmd->iscsi_opcode != ISCSI_OP_SCSI_CMD) &&
 349                    (cmd->iscsi_opcode != ISCSI_OP_NOOP_OUT)) {
 350                        pr_debug("Not performing reallegiance on"
 351                                " Opcode: 0x%02x, ITT: 0x%08x, CmdSN: 0x%08x,"
 352                                " CID: %hu\n", cmd->iscsi_opcode,
 353                                cmd->init_task_tag, cmd->cmd_sn, conn->cid);
 354
 355                        list_del_init(&cmd->i_conn_node);
 356                        spin_unlock_bh(&conn->cmd_lock);
 357                        iscsit_free_cmd(cmd, true);
 358                        spin_lock_bh(&conn->cmd_lock);
 359                        continue;
 360                }
 361
 362                /*
 363                 * Special case where commands greater than or equal to
 364                 * the session's ExpCmdSN are attached to the connection
 365                 * list but not to the out of order CmdSN list.  The one
 366                 * obvious case is when a command with immediate data
 367                 * attached must only check the CmdSN against ExpCmdSN
 368                 * after the data is received.  The special case below
 369                 * is when the connection fails before data is received,
 370                 * but also may apply to other PDUs, so it has been
 371                 * made generic here.
 372                 */
 373                if (!(cmd->cmd_flags & ICF_OOO_CMDSN) && !cmd->immediate_cmd &&
 374                     iscsi_sna_gte(cmd->cmd_sn, conn->sess->exp_cmd_sn)) {
 375                        list_del_init(&cmd->i_conn_node);
 376                        spin_unlock_bh(&conn->cmd_lock);
 377                        iscsit_free_cmd(cmd, true);
 378                        spin_lock_bh(&conn->cmd_lock);
 379                        continue;
 380                }
 381
 382                cmd_count++;
 383                pr_debug("Preparing Opcode: 0x%02x, ITT: 0x%08x,"
 384                        " CmdSN: 0x%08x, StatSN: 0x%08x, CID: %hu for"
 385                        " reallegiance.\n", cmd->iscsi_opcode,
 386                        cmd->init_task_tag, cmd->cmd_sn, cmd->stat_sn,
 387                        conn->cid);
 388
 389                cmd->deferred_i_state = cmd->i_state;
 390                cmd->i_state = ISTATE_IN_CONNECTION_RECOVERY;
 391
 392                if (cmd->data_direction == DMA_TO_DEVICE)
 393                        iscsit_stop_dataout_timer(cmd);
 394
 395                cmd->sess = conn->sess;
 396
 397                list_del_init(&cmd->i_conn_node);
 398                spin_unlock_bh(&conn->cmd_lock);
 399
 400                iscsit_free_all_datain_reqs(cmd);
 401
 402                transport_wait_for_tasks(&cmd->se_cmd);
 403                /*
 404                 * Add the struct iscsi_cmd to the connection recovery cmd list
 405                 */
 406                spin_lock(&cr->conn_recovery_cmd_lock);
 407                list_add_tail(&cmd->i_conn_node, &cr->conn_recovery_cmd_list);
 408                spin_unlock(&cr->conn_recovery_cmd_lock);
 409
 410                spin_lock_bh(&conn->cmd_lock);
 411                cmd->cr = cr;
 412                cmd->conn = NULL;
 413        }
 414        spin_unlock_bh(&conn->cmd_lock);
 415        /*
 416         * Fill in the various values in the preallocated struct iscsi_conn_recovery.
 417         */
 418        cr->cid = conn->cid;
 419        cr->cmd_count = cmd_count;
 420        cr->maxrecvdatasegmentlength = conn->conn_ops->MaxRecvDataSegmentLength;
 421        cr->maxxmitdatasegmentlength = conn->conn_ops->MaxXmitDataSegmentLength;
 422        cr->sess = conn->sess;
 423
 424        iscsit_attach_inactive_connection_recovery_entry(conn->sess, cr);
 425
 426        return 0;
 427}
 428
 429int iscsit_connection_recovery_transport_reset(struct iscsi_conn *conn)
 430{
 431        atomic_set(&conn->connection_recovery, 1);
 432
 433        if (iscsit_close_connection(conn) < 0)
 434                return -1;
 435
 436        return 0;
 437}
 438