drivers/target/iscsi/iscsi_target_tmr.c

   1 /*******************************************************************************
   2  * This file contains the iSCSI Target specific Task Management functions.
   3  *
   4  * \u00a9 Copyright 2007-2011 RisingTide Systems LLC.
   5  *
   6  * Licensed to the Linux Foundation under the General Public License (GPL) version 2.
   7  *
   8  * Author: Nicholas A. Bellinger <nab@linux-iscsi.org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  ******************************************************************************/
  20
  21 #include <asm/unaligned.h>
  22 #include <scsi/scsi_device.h>
  23 #include <scsi/iscsi_proto.h>
  24 #include <target/target_core_base.h>
  25 #include <target/target_core_fabric.h>
  26
  27 #include "iscsi_target_core.h"
  28 #include "iscsi_target_seq_pdu_list.h"
  29 #include "iscsi_target_datain_values.h"
  30 #include "iscsi_target_device.h"
  31 #include "iscsi_target_erl0.h"
  32 #include "iscsi_target_erl1.h"
  33 #include "iscsi_target_erl2.h"
  34 #include "iscsi_target_tmr.h"
  35 #include "iscsi_target_tpg.h"
  36 #include "iscsi_target_util.h"
  37 #include "iscsi_target.h"
  38
  39 u8 iscsit_tmr_abort_task(
  40         struct iscsi_cmd *cmd,
  41         unsigned char *buf)
  42 {
  43         struct iscsi_cmd *ref_cmd;
  44         struct iscsi_conn *conn = cmd->conn;
  45         struct iscsi_tmr_req *tmr_req = cmd->tmr_req;
  46         struct se_tmr_req *se_tmr = cmd->se_cmd.se_tmr_req;
  47         struct iscsi_tm *hdr = (struct iscsi_tm *) buf;
  48
  49         ref_cmd = iscsit_find_cmd_from_itt(conn, hdr->rtt);
  50         if (!ref_cmd) {
  51                 pr_err("Unable to locate RefTaskTag: 0x%08x on CID:"
  52                         " %hu.\n", hdr->rtt, conn->cid);
  53                 return ((hdr->refcmdsn >= conn->sess->exp_cmd_sn) &&
  54                         (hdr->refcmdsn <= conn->sess->max_cmd_sn)) ?
  55                         ISCSI_TMF_RSP_COMPLETE : ISCSI_TMF_RSP_NO_TASK;
  56         }
  57         if (ref_cmd->cmd_sn != hdr->refcmdsn) {
  58                 pr_err("RefCmdSN 0x%08x does not equal"
  59                         " task's CmdSN 0x%08x. Rejecting ABORT_TASK.\n",
  60                         hdr->refcmdsn, ref_cmd->cmd_sn);
  61                 return ISCSI_TMF_RSP_REJECTED;
  62         }
  63
  64         se_tmr->ref_task_tag            = hdr->rtt;
  65         tmr_req->ref_cmd                = ref_cmd;
  66         tmr_req->ref_cmd_sn             = hdr->refcmdsn;
  67         tmr_req->exp_data_sn            = hdr->exp_datasn;
  68
  69         return ISCSI_TMF_RSP_COMPLETE;
  70 }
  71
  72 /*
  73  *      Called from iscsit_handle_task_mgt_cmd().
  74  */
  75 int iscsit_tmr_task_warm_reset(
  76         struct iscsi_conn *conn,
  77         struct iscsi_tmr_req *tmr_req,
  78         unsigned char *buf)
  79 {
  80         struct iscsi_session *sess = conn->sess;
  81         struct iscsi_node_attrib *na = iscsit_tpg_get_node_attrib(sess);
  82
  83         if (!na->tmr_warm_reset) {
  84                 pr_err("TMR Opcode TARGET_WARM_RESET authorization"
  85                         " failed for Initiator Node: %s\n",
  86                         sess->se_sess->se_node_acl->initiatorname);
  87                  return -1;
  88         }
  89         /*
  90          * Do the real work in transport_generic_do_tmr().
  91          */
  92         return 0;
  93 }
  94
  95 int iscsit_tmr_task_cold_reset(
  96         struct iscsi_conn *conn,
  97         struct iscsi_tmr_req *tmr_req,
  98         unsigned char *buf)
  99 {
 100         struct iscsi_session *sess = conn->sess;
 101         struct iscsi_node_attrib *na = iscsit_tpg_get_node_attrib(sess);
 102
 103         if (!na->tmr_cold_reset) {
 104                 pr_err("TMR Opcode TARGET_COLD_RESET authorization"
 105                         " failed for Initiator Node: %s\n",
 106                         sess->se_sess->se_node_acl->initiatorname);
 107                 return -1;
 108         }
 109         /*
 110          * Do the real work in transport_generic_do_tmr().
 111          */
 112         return 0;
 113 }
 114
 115 u8 iscsit_tmr_task_reassign(
 116         struct iscsi_cmd *cmd,
 117         unsigned char *buf)
 118 {
 119         struct iscsi_cmd *ref_cmd = NULL;
 120         struct iscsi_conn *conn = cmd->conn;
 121         struct iscsi_conn_recovery *cr = NULL;
 122         struct iscsi_tmr_req *tmr_req = cmd->tmr_req;
 123         struct se_tmr_req *se_tmr = cmd->se_cmd.se_tmr_req;
 124         struct iscsi_tm *hdr = (struct iscsi_tm *) buf;
 125         int ret, ref_lun;
 126
 127         pr_debug("Got TASK_REASSIGN TMR ITT: 0x%08x,"
 128                 " RefTaskTag: 0x%08x, ExpDataSN: 0x%08x, CID: %hu\n",
 129                 hdr->itt, hdr->rtt, hdr->exp_datasn, conn->cid);
 130
 131         if (conn->sess->sess_ops->ErrorRecoveryLevel != 2) {
 132                 pr_err("TMR TASK_REASSIGN not supported in ERL<2,"
 133                                 " ignoring request.\n");
 134                 return ISCSI_TMF_RSP_NOT_SUPPORTED;
 135         }
 136
 137         ret = iscsit_find_cmd_for_recovery(conn->sess, &ref_cmd, &cr, hdr->rtt);
 138         if (ret == -2) {
 139                 pr_err("Command ITT: 0x%08x is still alligent to CID:"
 140                         " %hu\n", ref_cmd->init_task_tag, cr->cid);
 141                 return ISCSI_TMF_RSP_TASK_ALLEGIANT;
 142         } else if (ret == -1) {
 143                 pr_err("Unable to locate RefTaskTag: 0x%08x in"
 144                         " connection recovery command list.\n", hdr->rtt);
 145                 return ISCSI_TMF_RSP_NO_TASK;
 146         }
 147         /*
 148          * Temporary check to prevent connection recovery for
 149          * connections with a differing MaxRecvDataSegmentLength.
 150          */
 151         if (cr->maxrecvdatasegmentlength !=
 152             conn->conn_ops->MaxRecvDataSegmentLength) {
 153                 pr_err("Unable to perform connection recovery for"
 154                         " differing MaxRecvDataSegmentLength, rejecting"
 155                         " TMR TASK_REASSIGN.\n");
 156                 return ISCSI_TMF_RSP_REJECTED;
 157         }
 158
 159         ref_lun = scsilun_to_int(&hdr->lun);
 160         if (ref_lun != ref_cmd->se_cmd.orig_fe_lun) {
 161                 pr_err("Unable to perform connection recovery for"
 162                         " differing ref_lun: %d ref_cmd orig_fe_lun: %u\n",
 163                         ref_lun, ref_cmd->se_cmd.orig_fe_lun);
 164                 return ISCSI_TMF_RSP_REJECTED;
 165         }
 166
 167         se_tmr->ref_task_tag            = hdr->rtt;
 168         tmr_req->ref_cmd                = ref_cmd;
 169         tmr_req->ref_cmd_sn             = hdr->refcmdsn;
 170         tmr_req->exp_data_sn            = hdr->exp_datasn;
 171         tmr_req->conn_recovery          = cr;
 172         tmr_req->task_reassign          = 1;
 173         /*
 174          * Command can now be reassigned to a new connection.
 175          * The task management response must be sent before the
 176          * reassignment actually happens.  See iscsi_tmr_post_handler().
 177          */
 178         return ISCSI_TMF_RSP_COMPLETE;
 179 }
 180
 181 static void iscsit_task_reassign_remove_cmd(
 182         struct iscsi_cmd *cmd,
 183         struct iscsi_conn_recovery *cr,
 184         struct iscsi_session *sess)
 185 {
 186         int ret;
 187
 188         spin_lock(&cr->conn_recovery_cmd_lock);
 189         ret = iscsit_remove_cmd_from_connection_recovery(cmd, sess);
 190         spin_unlock(&cr->conn_recovery_cmd_lock);
 191         if (!ret) {
 192                 pr_debug("iSCSI connection recovery successful for CID:"
 193                         " %hu on SID: %u\n", cr->cid, sess->sid);
 194                 iscsit_remove_active_connection_recovery_entry(cr, sess);
 195         }
 196 }
 197
 198 static int iscsit_task_reassign_complete_nop_out(
 199         struct iscsi_tmr_req *tmr_req,
 200         struct iscsi_conn *conn)
 201 {
 202         struct iscsi_cmd *cmd = tmr_req->ref_cmd;
 203         struct iscsi_conn_recovery *cr;
 204
 205         if (!cmd->cr) {
 206                 pr_err("struct iscsi_conn_recovery pointer for ITT: 0x%08x"
 207                         " is NULL!\n", cmd->init_task_tag);
 208                 return -1;
 209         }
 210         cr = cmd->cr;
 211
 212         /*
 213          * Reset the StatSN so a new one for this commands new connection
 214          * will be assigned.
 215          * Reset the ExpStatSN as well so we may receive Status SNACKs.
 216          */
 217         cmd->stat_sn = cmd->exp_stat_sn = 0;
 218
 219         iscsit_task_reassign_remove_cmd(cmd, cr, conn->sess);
 220
 221         spin_lock_bh(&conn->cmd_lock);
 222         list_add_tail(&cmd->i_conn_node, &conn->conn_cmd_list);
 223         spin_unlock_bh(&conn->cmd_lock);
 224
 225         cmd->i_state = ISTATE_SEND_NOPIN;
 226         iscsit_add_cmd_to_response_queue(cmd, conn, cmd->i_state);
 227         return 0;
 228 }
 229
 230 static int iscsit_task_reassign_complete_write(
 231         struct iscsi_cmd *cmd,
 232         struct iscsi_tmr_req *tmr_req)
 233 {
 234         int no_build_r2ts = 0;
 235         u32 length = 0, offset = 0;
 236         struct iscsi_conn *conn = cmd->conn;
 237         struct se_cmd *se_cmd = &cmd->se_cmd;
 238         /*
 239          * The Initiator must not send a R2T SNACK with a Begrun less than
 240          * the TMR TASK_REASSIGN's ExpDataSN.
 241          */
 242         if (!tmr_req->exp_data_sn) {
 243                 cmd->cmd_flags &= ~ICF_GOT_DATACK_SNACK;
 244                 cmd->acked_data_sn = 0;
 245         } else {
 246                 cmd->cmd_flags |= ICF_GOT_DATACK_SNACK;
 247                 cmd->acked_data_sn = (tmr_req->exp_data_sn - 1);
 248         }
 249
 250         /*
 251          * The TMR TASK_REASSIGN's ExpDataSN contains the next R2TSN the
 252          * Initiator is expecting.  The Target controls all WRITE operations
 253          * so if we have received all DataOUT we can safety ignore Initiator.
 254          */
 255         if (cmd->cmd_flags & ICF_GOT_LAST_DATAOUT) {
 256                 if (!(cmd->se_cmd.transport_state & CMD_T_SENT)) {
 257                         pr_debug("WRITE ITT: 0x%08x: t_state: %d"
 258                                 " never sent to transport\n",
 259                                 cmd->init_task_tag, cmd->se_cmd.t_state);
 260                         target_execute_cmd(se_cmd);
 261                         return 0;
 262                 }
 263
 264                 cmd->i_state = ISTATE_SEND_STATUS;
 265                 iscsit_add_cmd_to_response_queue(cmd, conn, cmd->i_state);
 266                 return 0;
 267         }
 268
 269         /*
 270          * Special case to deal with DataSequenceInOrder=No and Non-Immeidate
 271          * Unsolicited DataOut.
 272          */
 273         if (cmd->unsolicited_data) {
 274                 cmd->unsolicited_data = 0;
 275
 276                 offset = cmd->next_burst_len = cmd->write_data_done;
 277
 278                 if ((conn->sess->sess_ops->FirstBurstLength - offset) >=
 279                      cmd->se_cmd.data_length) {
 280                         no_build_r2ts = 1;
 281                         length = (cmd->se_cmd.data_length - offset);
 282                 } else
 283                         length = (conn->sess->sess_ops->FirstBurstLength - offset);
 284
 285                 spin_lock_bh(&cmd->r2t_lock);
 286                 if (iscsit_add_r2t_to_list(cmd, offset, length, 0, 0) < 0) {
 287                         spin_unlock_bh(&cmd->r2t_lock);
 288                         return -1;
 289                 }
 290                 cmd->outstanding_r2ts++;
 291                 spin_unlock_bh(&cmd->r2t_lock);
 292
 293                 if (no_build_r2ts)
 294                         return 0;
 295         }
 296         /*
 297          * iscsit_build_r2ts_for_cmd() can handle the rest from here.
 298          */
 299         return iscsit_build_r2ts_for_cmd(cmd, conn, true);
 300 }
 301
 302 static int iscsit_task_reassign_complete_read(
 303         struct iscsi_cmd *cmd,
 304         struct iscsi_tmr_req *tmr_req)
 305 {
 306         struct iscsi_conn *conn = cmd->conn;
 307         struct iscsi_datain_req *dr;
 308         struct se_cmd *se_cmd = &cmd->se_cmd;
 309         /*
 310          * The Initiator must not send a Data SNACK with a BegRun less than
 311          * the TMR TASK_REASSIGN's ExpDataSN.
 312          */
 313         if (!tmr_req->exp_data_sn) {
 314                 cmd->cmd_flags &= ~ICF_GOT_DATACK_SNACK;
 315                 cmd->acked_data_sn = 0;
 316         } else {
 317                 cmd->cmd_flags |= ICF_GOT_DATACK_SNACK;
 318                 cmd->acked_data_sn = (tmr_req->exp_data_sn - 1);
 319         }
 320
 321         if (!(cmd->se_cmd.transport_state & CMD_T_SENT)) {
 322                 pr_debug("READ ITT: 0x%08x: t_state: %d never sent to"
 323                         " transport\n", cmd->init_task_tag,
 324                         cmd->se_cmd.t_state);
 325                 transport_handle_cdb_direct(se_cmd);
 326                 return 0;
 327         }
 328
 329         if (!(se_cmd->transport_state & CMD_T_COMPLETE)) {
 330                 pr_err("READ ITT: 0x%08x: t_state: %d, never returned"
 331                         " from transport\n", cmd->init_task_tag,
 332                         cmd->se_cmd.t_state);
 333                 return -1;
 334         }
 335
 336         dr = iscsit_allocate_datain_req();
 337         if (!dr)
 338                 return -1;
 339         /*
 340          * The TMR TASK_REASSIGN's ExpDataSN contains the next DataSN the
 341          * Initiator is expecting.
 342          */
 343         dr->data_sn = dr->begrun = tmr_req->exp_data_sn;
 344         dr->runlength = 0;
 345         dr->generate_recovery_values = 1;
 346         dr->recovery = DATAIN_CONNECTION_RECOVERY;
 347
 348         iscsit_attach_datain_req(cmd, dr);
 349
 350         cmd->i_state = ISTATE_SEND_DATAIN;
 351         iscsit_add_cmd_to_response_queue(cmd, conn, cmd->i_state);
 352         return 0;
 353 }
 354
 355 static int iscsit_task_reassign_complete_none(
 356         struct iscsi_cmd *cmd,
 357         struct iscsi_tmr_req *tmr_req)
 358 {
 359         struct iscsi_conn *conn = cmd->conn;
 360
 361         cmd->i_state = ISTATE_SEND_STATUS;
 362         iscsit_add_cmd_to_response_queue(cmd, conn, cmd->i_state);
 363         return 0;
 364 }
 365
 366 static int iscsit_task_reassign_complete_scsi_cmnd(
 367         struct iscsi_tmr_req *tmr_req,
 368         struct iscsi_conn *conn)
 369 {
 370         struct iscsi_cmd *cmd = tmr_req->ref_cmd;
 371         struct iscsi_conn_recovery *cr;
 372
 373         if (!cmd->cr) {
 374                 pr_err("struct iscsi_conn_recovery pointer for ITT: 0x%08x"
 375                         " is NULL!\n", cmd->init_task_tag);
 376                 return -1;
 377         }
 378         cr = cmd->cr;
 379
 380         /*
 381          * Reset the StatSN so a new one for this commands new connection
 382          * will be assigned.
 383          * Reset the ExpStatSN as well so we may receive Status SNACKs.
 384          */
 385         cmd->stat_sn = cmd->exp_stat_sn = 0;
 386
 387         iscsit_task_reassign_remove_cmd(cmd, cr, conn->sess);
 388
 389         spin_lock_bh(&conn->cmd_lock);
 390         list_add_tail(&cmd->i_conn_node, &conn->conn_cmd_list);
 391         spin_unlock_bh(&conn->cmd_lock);
 392
 393         if (cmd->se_cmd.se_cmd_flags & SCF_SENT_CHECK_CONDITION) {
 394                 cmd->i_state = ISTATE_SEND_STATUS;
 395                 iscsit_add_cmd_to_response_queue(cmd, conn, cmd->i_state);
 396                 return 0;
 397         }
 398
 399         switch (cmd->data_direction) {
 400         case DMA_TO_DEVICE:
 401                 return iscsit_task_reassign_complete_write(cmd, tmr_req);
 402         case DMA_FROM_DEVICE:
 403                 return iscsit_task_reassign_complete_read(cmd, tmr_req);
 404         case DMA_NONE:
 405                 return iscsit_task_reassign_complete_none(cmd, tmr_req);
 406         default:
 407                 pr_err("Unknown cmd->data_direction: 0x%02x\n",
 408                                 cmd->data_direction);
 409                 return -1;
 410         }
 411
 412         return 0;
 413 }
 414
 415 static int iscsit_task_reassign_complete(
 416         struct iscsi_tmr_req *tmr_req,
 417         struct iscsi_conn *conn)
 418 {
 419         struct iscsi_cmd *cmd;
 420         int ret = 0;
 421
 422         if (!tmr_req->ref_cmd) {
 423                 pr_err("TMR Request is missing a RefCmd struct iscsi_cmd.\n");
 424                 return -1;
 425         }
 426         cmd = tmr_req->ref_cmd;
 427
 428         cmd->conn = conn;
 429
 430         switch (cmd->iscsi_opcode) {
 431         case ISCSI_OP_NOOP_OUT:
 432                 ret = iscsit_task_reassign_complete_nop_out(tmr_req, conn);
 433                 break;
 434         case ISCSI_OP_SCSI_CMD:
 435                 ret = iscsit_task_reassign_complete_scsi_cmnd(tmr_req, conn);
 436                 break;
 437         default:
 438                  pr_err("Illegal iSCSI Opcode 0x%02x during"
 439                         " command realligence\n", cmd->iscsi_opcode);
 440                 return -1;
 441         }
 442
 443         if (ret != 0)
 444                 return ret;
 445
 446         pr_debug("Completed connection realligence for Opcode: 0x%02x,"
 447                 " ITT: 0x%08x to CID: %hu.\n", cmd->iscsi_opcode,
 448                         cmd->init_task_tag, conn->cid);
 449
 450         return 0;
 451 }
 452
 453 /*
 454  *      Handles special after-the-fact actions related to TMRs.
 455  *      Right now the only one that its really needed for is
 456  *      connection recovery releated TASK_REASSIGN.
 457  */
 458 extern int iscsit_tmr_post_handler(struct iscsi_cmd *cmd, struct iscsi_conn *conn)
 459 {
 460         struct iscsi_tmr_req *tmr_req = cmd->tmr_req;
 461         struct se_tmr_req *se_tmr = cmd->se_cmd.se_tmr_req;
 462
 463         if (tmr_req->task_reassign &&
 464            (se_tmr->response == ISCSI_TMF_RSP_COMPLETE))
 465                 return iscsit_task_reassign_complete(tmr_req, conn);
 466
 467         return 0;
 468 }
 469
 470 /*
 471  *      Nothing to do here, but leave it for good measure. :-)
 472  */
 473 int iscsit_task_reassign_prepare_read(
 474         struct iscsi_tmr_req *tmr_req,
 475         struct iscsi_conn *conn)
 476 {
 477         return 0;
 478 }
 479
 480 static void iscsit_task_reassign_prepare_unsolicited_dataout(
 481         struct iscsi_cmd *cmd,
 482         struct iscsi_conn *conn)
 483 {
 484         int i, j;
 485         struct iscsi_pdu *pdu = NULL;
 486         struct iscsi_seq *seq = NULL;
 487
 488         if (conn->sess->sess_ops->DataSequenceInOrder) {
 489                 cmd->data_sn = 0;
 490
 491                 if (cmd->immediate_data)
 492                         cmd->r2t_offset += (cmd->first_burst_len -
 493                                 cmd->seq_start_offset);
 494
 495                 if (conn->sess->sess_ops->DataPDUInOrder) {
 496                         cmd->write_data_done -= (cmd->immediate_data) ?
 497                                                 (cmd->first_burst_len -
 498                                                  cmd->seq_start_offset) :
 499                                                  cmd->first_burst_len;
 500                         cmd->first_burst_len = 0;
 501                         return;
 502                 }
 503
 504                 for (i = 0; i < cmd->pdu_count; i++) {
 505                         pdu = &cmd->pdu_list[i];
 506
 507                         if (pdu->status != ISCSI_PDU_RECEIVED_OK)
 508                                 continue;
 509
 510                         if ((pdu->offset >= cmd->seq_start_offset) &&
 511                            ((pdu->offset + pdu->length) <=
 512                              cmd->seq_end_offset)) {
 513                                 cmd->first_burst_len -= pdu->length;
 514                                 cmd->write_data_done -= pdu->length;
 515                                 pdu->status = ISCSI_PDU_NOT_RECEIVED;
 516                         }
 517                 }
 518         } else {
 519                 for (i = 0; i < cmd->seq_count; i++) {
 520                         seq = &cmd->seq_list[i];
 521
 522                         if (seq->type != SEQTYPE_UNSOLICITED)
 523                                 continue;
 524
 525                         cmd->write_data_done -=
 526                                         (seq->offset - seq->orig_offset);
 527                         cmd->first_burst_len = 0;
 528                         seq->data_sn = 0;
 529                         seq->offset = seq->orig_offset;
 530                         seq->next_burst_len = 0;
 531                         seq->status = DATAOUT_SEQUENCE_WITHIN_COMMAND_RECOVERY;
 532
 533                         if (conn->sess->sess_ops->DataPDUInOrder)
 534                                 continue;
 535
 536                         for (j = 0; j < seq->pdu_count; j++) {
 537                                 pdu = &cmd->pdu_list[j+seq->pdu_start];
 538
 539                                 if (pdu->status != ISCSI_PDU_RECEIVED_OK)
 540                                         continue;
 541
 542                                 pdu->status = ISCSI_PDU_NOT_RECEIVED;
 543                         }
 544                 }
 545         }
 546 }
 547
 548 int iscsit_task_reassign_prepare_write(
 549         struct iscsi_tmr_req *tmr_req,
 550         struct iscsi_conn *conn)
 551 {
 552         struct iscsi_cmd *cmd = tmr_req->ref_cmd;
 553         struct iscsi_pdu *pdu = NULL;
 554         struct iscsi_r2t *r2t = NULL, *r2t_tmp;
 555         int first_incomplete_r2t = 1, i = 0;
 556
 557         /*
 558          * The command was in the process of receiving Unsolicited DataOUT when
 559          * the connection failed.
 560          */
 561         if (cmd->unsolicited_data)
 562                 iscsit_task_reassign_prepare_unsolicited_dataout(cmd, conn);
 563
 564         /*
 565          * The Initiator is requesting R2Ts starting from zero,  skip
 566          * checking acknowledged R2Ts and start checking struct iscsi_r2ts
 567          * greater than zero.
 568          */
 569         if (!tmr_req->exp_data_sn)
 570                 goto drop_unacknowledged_r2ts;
 571
 572         /*
 573          * We now check that the PDUs in DataOUT sequences below
 574          * the TMR TASK_REASSIGN ExpDataSN (R2TSN the Initiator is
 575          * expecting next) have all the DataOUT they require to complete
 576          * the DataOUT sequence.  First scan from R2TSN 0 to TMR
 577          * TASK_REASSIGN ExpDataSN-1.
 578          *
 579          * If we have not received all DataOUT in question,  we must
 580          * make sure to make the appropriate changes to values in
 581          * struct iscsi_cmd (and elsewhere depending on session parameters)
 582          * so iscsit_build_r2ts_for_cmd() in iscsit_task_reassign_complete_write()
 583          * will resend a new R2T for the DataOUT sequences in question.
 584          */
 585         spin_lock_bh(&cmd->r2t_lock);
 586         if (list_empty(&cmd->cmd_r2t_list)) {
 587                 spin_unlock_bh(&cmd->r2t_lock);
 588                 return -1;
 589         }
 590
 591         list_for_each_entry(r2t, &cmd->cmd_r2t_list, r2t_list) {
 592
 593                 if (r2t->r2t_sn >= tmr_req->exp_data_sn)
 594                         continue;
 595                 /*
 596                  * Safely ignore Recovery R2Ts and R2Ts that have completed
 597                  * DataOUT sequences.
 598                  */
 599                 if (r2t->seq_complete)
 600                         continue;
 601
 602                 if (r2t->recovery_r2t)
 603                         continue;
 604
 605                 /*
 606                  *                 DataSequenceInOrder=Yes:
 607                  *
 608                  * Taking into account the iSCSI implementation requirement of
 609                  * MaxOutstandingR2T=1 while ErrorRecoveryLevel>0 and
 610                  * DataSequenceInOrder=Yes, we must take into consideration
 611                  * the following:
 612                  *
 613                  *                  DataSequenceInOrder=No:
 614                  *
 615                  * Taking into account that the Initiator controls the (possibly
 616                  * random) PDU Order in (possibly random) Sequence Order of
 617                  * DataOUT the target requests with R2Ts,  we must take into
 618                  * consideration the following:
 619                  *
 620                  *      DataPDUInOrder=Yes for DataSequenceInOrder=[Yes,No]:
 621                  *
 622                  * While processing non-complete R2T DataOUT sequence requests
 623                  * the Target will re-request only the total sequence length
 624                  * minus current received offset.  This is because we must
 625                  * assume the initiator will continue sending DataOUT from the
 626                  * last PDU before the connection failed.
 627                  *
 628                  *      DataPDUInOrder=No for DataSequenceInOrder=[Yes,No]:
 629                  *
 630                  * While processing non-complete R2T DataOUT sequence requests
 631                  * the Target will re-request the entire DataOUT sequence if
 632                  * any single PDU is missing from the sequence.  This is because
 633                  * we have no logical method to determine the next PDU offset,
 634                  * and we must assume the Initiator will be sending any random
 635                  * PDU offset in the current sequence after TASK_REASSIGN
 636                  * has completed.
 637                  */
 638                 if (conn->sess->sess_ops->DataSequenceInOrder) {
 639                         if (!first_incomplete_r2t) {
 640                                 cmd->r2t_offset -= r2t->xfer_len;
 641                                 goto next;
 642                         }
 643
 644                         if (conn->sess->sess_ops->DataPDUInOrder) {
 645                                 cmd->data_sn = 0;
 646                                 cmd->r2t_offset -= (r2t->xfer_len -
 647                                         cmd->next_burst_len);
 648                                 first_incomplete_r2t = 0;
 649                                 goto next;
 650                         }
 651
 652                         cmd->data_sn = 0;
 653                         cmd->r2t_offset -= r2t->xfer_len;
 654
 655                         for (i = 0; i < cmd->pdu_count; i++) {
 656                                 pdu = &cmd->pdu_list[i];
 657
 658                                 if (pdu->status != ISCSI_PDU_RECEIVED_OK)
 659                                         continue;
 660
 661                                 if ((pdu->offset >= r2t->offset) &&
 662                                     (pdu->offset < (r2t->offset +
 663                                                 r2t->xfer_len))) {
 664                                         cmd->next_burst_len -= pdu->length;
 665                                         cmd->write_data_done -= pdu->length;
 666                                         pdu->status = ISCSI_PDU_NOT_RECEIVED;
 667                                 }
 668                         }
 669
 670                         first_incomplete_r2t = 0;
 671                 } else {
 672                         struct iscsi_seq *seq;
 673
 674                         seq = iscsit_get_seq_holder(cmd, r2t->offset,
 675                                         r2t->xfer_len);
 676                         if (!seq) {
 677                                 spin_unlock_bh(&cmd->r2t_lock);
 678                                 return -1;
 679                         }
 680
 681                         cmd->write_data_done -=
 682                                         (seq->offset - seq->orig_offset);
 683                         seq->data_sn = 0;
 684                         seq->offset = seq->orig_offset;
 685                         seq->next_burst_len = 0;
 686                         seq->status = DATAOUT_SEQUENCE_WITHIN_COMMAND_RECOVERY;
 687
 688                         cmd->seq_send_order--;
 689
 690                         if (conn->sess->sess_ops->DataPDUInOrder)
 691                                 goto next;
 692
 693                         for (i = 0; i < seq->pdu_count; i++) {
 694                                 pdu = &cmd->pdu_list[i+seq->pdu_start];
 695
 696                                 if (pdu->status != ISCSI_PDU_RECEIVED_OK)
 697                                         continue;
 698
 699                                 pdu->status = ISCSI_PDU_NOT_RECEIVED;
 700                         }
 701                 }
 702
 703 next:
 704                 cmd->outstanding_r2ts--;
 705         }
 706         spin_unlock_bh(&cmd->r2t_lock);
 707
 708         /*
 709          * We now drop all unacknowledged R2Ts, ie: ExpDataSN from TMR
 710          * TASK_REASSIGN to the last R2T in the list..  We are also careful
 711          * to check that the Initiator is not requesting R2Ts for DataOUT
 712          * sequences it has already completed.
 713          *
 714          * Free each R2T in question and adjust values in struct iscsi_cmd
 715          * accordingly so iscsit_build_r2ts_for_cmd() do the rest of
 716          * the work after the TMR TASK_REASSIGN Response is sent.
 717          */
 718 drop_unacknowledged_r2ts:
 719
 720         cmd->cmd_flags &= ~ICF_SENT_LAST_R2T;
 721         cmd->r2t_sn = tmr_req->exp_data_sn;
 722
 723         spin_lock_bh(&cmd->r2t_lock);
 724         list_for_each_entry_safe(r2t, r2t_tmp, &cmd->cmd_r2t_list, r2t_list) {
 725                 /*
 726                  * Skip up to the R2T Sequence number provided by the
 727                  * iSCSI TASK_REASSIGN TMR
 728                  */
 729                 if (r2t->r2t_sn < tmr_req->exp_data_sn)
 730                         continue;
 731
 732                 if (r2t->seq_complete) {
 733                         pr_err("Initiator is requesting R2Ts from"
 734                                 " R2TSN: 0x%08x, but R2TSN: 0x%08x, Offset: %u,"
 735                                 " Length: %u is already complete."
 736                                 "   BAD INITIATOR ERL=2 IMPLEMENTATION!\n",
 737                                 tmr_req->exp_data_sn, r2t->r2t_sn,
 738                                 r2t->offset, r2t->xfer_len);
 739                         spin_unlock_bh(&cmd->r2t_lock);
 740                         return -1;
 741                 }
 742
 743                 if (r2t->recovery_r2t) {
 744                         iscsit_free_r2t(r2t, cmd);
 745                         continue;
 746                 }
 747
 748                 /*                 DataSequenceInOrder=Yes:
 749                  *
 750                  * Taking into account the iSCSI implementation requirement of
 751                  * MaxOutstandingR2T=1 while ErrorRecoveryLevel>0 and
 752                  * DataSequenceInOrder=Yes, it's safe to subtract the R2Ts
 753                  * entire transfer length from the commands R2T offset marker.
 754                  *
 755                  *                 DataSequenceInOrder=No:
 756                  *
 757                  * We subtract the difference from struct iscsi_seq between the
 758                  * current offset and original offset from cmd->write_data_done
 759                  * for account for DataOUT PDUs already received.  Then reset
 760                  * the current offset to the original and zero out the current
 761                  * burst length,  to make sure we re-request the entire DataOUT
 762                  * sequence.
 763                  */
 764                 if (conn->sess->sess_ops->DataSequenceInOrder)
 765                         cmd->r2t_offset -= r2t->xfer_len;
 766                 else
 767                         cmd->seq_send_order--;
 768
 769                 cmd->outstanding_r2ts--;
 770                 iscsit_free_r2t(r2t, cmd);
 771         }
 772         spin_unlock_bh(&cmd->r2t_lock);
 773
 774         return 0;
 775 }
 776
 777 /*
 778  *      Performs sanity checks TMR TASK_REASSIGN's ExpDataSN for
 779  *      a given struct iscsi_cmd.
 780  */
 781 int iscsit_check_task_reassign_expdatasn(
 782         struct iscsi_tmr_req *tmr_req,
 783         struct iscsi_conn *conn)
 784 {
 785         struct iscsi_cmd *ref_cmd = tmr_req->ref_cmd;
 786
 787         if (ref_cmd->iscsi_opcode != ISCSI_OP_SCSI_CMD)
 788                 return 0;
 789
 790         if (ref_cmd->se_cmd.se_cmd_flags & SCF_SENT_CHECK_CONDITION)
 791                 return 0;
 792
 793         if (ref_cmd->data_direction == DMA_NONE)
 794                 return 0;
 795
 796         /*
 797          * For READs the TMR TASK_REASSIGNs ExpDataSN contains the next DataSN
 798          * of DataIN the Initiator is expecting.
 799          *
 800          * Also check that the Initiator is not re-requesting DataIN that has
 801          * already been acknowledged with a DataAck SNACK.
 802          */
 803         if (ref_cmd->data_direction == DMA_FROM_DEVICE) {
 804                 if (tmr_req->exp_data_sn > ref_cmd->data_sn) {
 805                         pr_err("Received ExpDataSN: 0x%08x for READ"
 806                                 " in TMR TASK_REASSIGN greater than command's"
 807                                 " DataSN: 0x%08x.\n", tmr_req->exp_data_sn,
 808                                 ref_cmd->data_sn);
 809                         return -1;
 810                 }
 811                 if ((ref_cmd->cmd_flags & ICF_GOT_DATACK_SNACK) &&
 812                     (tmr_req->exp_data_sn <= ref_cmd->acked_data_sn)) {
 813                         pr_err("Received ExpDataSN: 0x%08x for READ"
 814                                 " in TMR TASK_REASSIGN for previously"
 815                                 " acknowledged DataIN: 0x%08x,"
 816                                 " protocol error\n", tmr_req->exp_data_sn,
 817                                 ref_cmd->acked_data_sn);
 818                         return -1;
 819                 }
 820                 return iscsit_task_reassign_prepare_read(tmr_req, conn);
 821         }
 822
 823         /*
 824          * For WRITEs the TMR TASK_REASSIGNs ExpDataSN contains the next R2TSN
 825          * for R2Ts the Initiator is expecting.
 826          *
 827          * Do the magic in iscsit_task_reassign_prepare_write().
 828          */
 829         if (ref_cmd->data_direction == DMA_TO_DEVICE) {
 830                 if (tmr_req->exp_data_sn > ref_cmd->r2t_sn) {
 831                         pr_err("Received ExpDataSN: 0x%08x for WRITE"
 832                                 " in TMR TASK_REASSIGN greater than command's"
 833                                 " R2TSN: 0x%08x.\n", tmr_req->exp_data_sn,
 834                                         ref_cmd->r2t_sn);
 835                         return -1;
 836                 }
 837                 return iscsit_task_reassign_prepare_write(tmr_req, conn);
 838         }
 839
 840         pr_err("Unknown iSCSI data_direction: 0x%02x\n",
 841                         ref_cmd->data_direction);
 842
 843         return -1;
 844 }