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/iscsi_proto.h>
  23 #include <target/target_core_base.h>
  24 #include <target/target_core_transport.h>
  25
  26 #include "iscsi_target_core.h"
  27 #include "iscsi_target_seq_pdu_list.h"
  28 #include "iscsi_target_datain_values.h"
  29 #include "iscsi_target_device.h"
  30 #include "iscsi_target_erl0.h"
  31 #include "iscsi_target_erl1.h"
  32 #include "iscsi_target_erl2.h"
  33 #include "iscsi_target_tmr.h"
  34 #include "iscsi_target_tpg.h"
  35 #include "iscsi_target_util.h"
  36 #include "iscsi_target.h"
  37
  38 u8 iscsit_tmr_abort_task(
  39         struct iscsi_cmd *cmd,
  40         unsigned char *buf)
  41 {
  42         struct iscsi_cmd *ref_cmd;
  43         struct iscsi_conn *conn = cmd->conn;
  44         struct iscsi_tmr_req *tmr_req = cmd->tmr_req;
  45         struct se_tmr_req *se_tmr = cmd->se_cmd.se_tmr_req;
  46         struct iscsi_tm *hdr = (struct iscsi_tm *) buf;
  47
  48         ref_cmd = iscsit_find_cmd_from_itt(conn, hdr->rtt);
  49         if (!ref_cmd) {
  50                 pr_err("Unable to locate RefTaskTag: 0x%08x on CID:"
  51                         " %hu.\n", hdr->rtt, conn->cid);
  52                 return ((hdr->refcmdsn >= conn->sess->exp_cmd_sn) &&
  53                         (hdr->refcmdsn <= conn->sess->max_cmd_sn)) ?
  54                         ISCSI_TMF_RSP_COMPLETE : ISCSI_TMF_RSP_NO_TASK;
  55         }
  56         if (ref_cmd->cmd_sn != hdr->refcmdsn) {
  57                 pr_err("RefCmdSN 0x%08x does not equal"
  58                         " task's CmdSN 0x%08x. Rejecting ABORT_TASK.\n",
  59                         hdr->refcmdsn, ref_cmd->cmd_sn);
  60                 return ISCSI_TMF_RSP_REJECTED;
  61         }
  62
  63         se_tmr->ref_task_tag            = hdr->rtt;
  64         se_tmr->ref_cmd                 = &ref_cmd->se_cmd;
  65         tmr_req->ref_cmd_sn             = hdr->refcmdsn;
  66         tmr_req->exp_data_sn            = hdr->exp_datasn;
  67
  68         return ISCSI_TMF_RSP_COMPLETE;
  69 }
  70
  71 /*
  72  *      Called from iscsit_handle_task_mgt_cmd().
  73  */
  74 int iscsit_tmr_task_warm_reset(
  75         struct iscsi_conn *conn,
  76         struct iscsi_tmr_req *tmr_req,
  77         unsigned char *buf)
  78 {
  79         struct iscsi_session *sess = conn->sess;
  80         struct iscsi_node_attrib *na = iscsit_tpg_get_node_attrib(sess);
  81 #if 0
  82         struct iscsi_init_task_mgt_cmnd *hdr =
  83                 (struct iscsi_init_task_mgt_cmnd *) buf;
  84 #endif
  85         if (!na->tmr_warm_reset) {
  86                 pr_err("TMR Opcode TARGET_WARM_RESET authorization"
  87                         " failed for Initiator Node: %s\n",
  88                         sess->se_sess->se_node_acl->initiatorname);
  89                  return -1;
  90         }
  91         /*
  92          * Do the real work in transport_generic_do_tmr().
  93          */
  94         return 0;
  95 }
  96
  97 int iscsit_tmr_task_cold_reset(
  98         struct iscsi_conn *conn,
  99         struct iscsi_tmr_req *tmr_req,
 100         unsigned char *buf)
 101 {
 102         struct iscsi_session *sess = conn->sess;
 103         struct iscsi_node_attrib *na = iscsit_tpg_get_node_attrib(sess);
 104
 105         if (!na->tmr_cold_reset) {
 106                 pr_err("TMR Opcode TARGET_COLD_RESET authorization"
 107                         " failed for Initiator Node: %s\n",
 108                         sess->se_sess->se_node_acl->initiatorname);
 109                 return -1;
 110         }
 111         /*
 112          * Do the real work in transport_generic_do_tmr().
 113          */
 114         return 0;
 115 }
 116
 117 u8 iscsit_tmr_task_reassign(
 118         struct iscsi_cmd *cmd,
 119         unsigned char *buf)
 120 {
 121         struct iscsi_cmd *ref_cmd = NULL;
 122         struct iscsi_conn *conn = cmd->conn;
 123         struct iscsi_conn_recovery *cr = NULL;
 124         struct iscsi_tmr_req *tmr_req = cmd->tmr_req;
 125         struct se_tmr_req *se_tmr = cmd->se_cmd.se_tmr_req;
 126         struct iscsi_tm *hdr = (struct iscsi_tm *) buf;
 127         int ret;
 128
 129         pr_debug("Got TASK_REASSIGN TMR ITT: 0x%08x,"
 130                 " RefTaskTag: 0x%08x, ExpDataSN: 0x%08x, CID: %hu\n",
 131                 hdr->itt, hdr->rtt, hdr->exp_datasn, conn->cid);
 132
 133         if (conn->sess->sess_ops->ErrorRecoveryLevel != 2) {
 134                 pr_err("TMR TASK_REASSIGN not supported in ERL<2,"
 135                                 " ignoring request.\n");
 136                 return ISCSI_TMF_RSP_NOT_SUPPORTED;
 137         }
 138
 139         ret = iscsit_find_cmd_for_recovery(conn->sess, &ref_cmd, &cr, hdr->rtt);
 140         if (ret == -2) {
 141                 pr_err("Command ITT: 0x%08x is still alligent to CID:"
 142                         " %hu\n", ref_cmd->init_task_tag, cr->cid);
 143                 return ISCSI_TMF_RSP_TASK_ALLEGIANT;
 144         } else if (ret == -1) {
 145                 pr_err("Unable to locate RefTaskTag: 0x%08x in"
 146                         " connection recovery command list.\n", hdr->rtt);
 147                 return ISCSI_TMF_RSP_NO_TASK;
 148         }
 149         /*
 150          * Temporary check to prevent connection recovery for
 151          * connections with a differing MaxRecvDataSegmentLength.
 152          */
 153         if (cr->maxrecvdatasegmentlength !=
 154             conn->conn_ops->MaxRecvDataSegmentLength) {
 155                 pr_err("Unable to perform connection recovery for"
 156                         " differing MaxRecvDataSegmentLength, rejecting"
 157                         " TMR TASK_REASSIGN.\n");
 158                 return ISCSI_TMF_RSP_REJECTED;
 159         }
 160
 161         se_tmr->ref_task_tag            = hdr->rtt;
 162         se_tmr->ref_cmd                 = &ref_cmd->se_cmd;
 163         se_tmr->ref_task_lun            = get_unaligned_le64(&hdr->lun);
 164         tmr_req->ref_cmd_sn             = hdr->refcmdsn;
 165         tmr_req->exp_data_sn            = hdr->exp_datasn;
 166         tmr_req->conn_recovery          = cr;
 167         tmr_req->task_reassign          = 1;
 168         /*
 169          * Command can now be reassigned to a new connection.
 170          * The task management response must be sent before the
 171          * reassignment actually happens.  See iscsi_tmr_post_handler().
 172          */
 173         return ISCSI_TMF_RSP_COMPLETE;
 174 }
 175
 176 static void iscsit_task_reassign_remove_cmd(
 177         struct iscsi_cmd *cmd,
 178         struct iscsi_conn_recovery *cr,
 179         struct iscsi_session *sess)
 180 {
 181         int ret;
 182
 183         spin_lock(&cr->conn_recovery_cmd_lock);
 184         ret = iscsit_remove_cmd_from_connection_recovery(cmd, sess);
 185         spin_unlock(&cr->conn_recovery_cmd_lock);
 186         if (!ret) {
 187                 pr_debug("iSCSI connection recovery successful for CID:"
 188                         " %hu on SID: %u\n", cr->cid, sess->sid);
 189                 iscsit_remove_active_connection_recovery_entry(cr, sess);
 190         }
 191 }
 192
 193 static int iscsit_task_reassign_complete_nop_out(
 194         struct iscsi_tmr_req *tmr_req,
 195         struct iscsi_conn *conn)
 196 {
 197         struct se_tmr_req *se_tmr = tmr_req->se_tmr_req;
 198         struct se_cmd *se_cmd = se_tmr->ref_cmd;
 199         struct iscsi_cmd *cmd = container_of(se_cmd, struct iscsi_cmd, se_cmd);
 200         struct iscsi_conn_recovery *cr;
 201
 202         if (!cmd->cr) {
 203                 pr_err("struct iscsi_conn_recovery pointer for ITT: 0x%08x"
 204                         " is NULL!\n", cmd->init_task_tag);
 205                 return -1;
 206         }
 207         cr = cmd->cr;
 208
 209         /*
 210          * Reset the StatSN so a new one for this commands new connection
 211          * will be assigned.
 212          * Reset the ExpStatSN as well so we may receive Status SNACKs.
 213          */
 214         cmd->stat_sn = cmd->exp_stat_sn = 0;
 215
 216         iscsit_task_reassign_remove_cmd(cmd, cr, conn->sess);
 217
 218         spin_lock_bh(&conn->cmd_lock);
 219         list_add_tail(&cmd->i_list, &conn->conn_cmd_list);
 220         spin_unlock_bh(&conn->cmd_lock);
 221
 222         cmd->i_state = ISTATE_SEND_NOPIN;
 223         iscsit_add_cmd_to_response_queue(cmd, conn, cmd->i_state);
 224         return 0;
 225 }
 226
 227 static int iscsit_task_reassign_complete_write(
 228         struct iscsi_cmd *cmd,
 229         struct iscsi_tmr_req *tmr_req)
 230 {
 231         int no_build_r2ts = 0;
 232         u32 length = 0, offset = 0;
 233         struct iscsi_conn *conn = cmd->conn;
 234         struct se_cmd *se_cmd = &cmd->se_cmd;
 235         /*
 236          * The Initiator must not send a R2T SNACK with a Begrun less than
 237          * the TMR TASK_REASSIGN's ExpDataSN.
 238          */
 239         if (!tmr_req->exp_data_sn) {
 240                 cmd->cmd_flags &= ~ICF_GOT_DATACK_SNACK;
 241                 cmd->acked_data_sn = 0;
 242         } else {
 243                 cmd->cmd_flags |= ICF_GOT_DATACK_SNACK;
 244                 cmd->acked_data_sn = (tmr_req->exp_data_sn - 1);
 245         }
 246
 247         /*
 248          * The TMR TASK_REASSIGN's ExpDataSN contains the next R2TSN the
 249          * Initiator is expecting.  The Target controls all WRITE operations
 250          * so if we have received all DataOUT we can safety ignore Initiator.
 251          */
 252         if (cmd->cmd_flags & ICF_GOT_LAST_DATAOUT) {
 253                 if (!atomic_read(&cmd->transport_sent)) {
 254                         pr_debug("WRITE ITT: 0x%08x: t_state: %d"
 255                                 " never sent to transport\n",
 256                                 cmd->init_task_tag, cmd->se_cmd.t_state);
 257                         return transport_generic_handle_data(se_cmd);
 258                 }
 259
 260                 cmd->i_state = ISTATE_SEND_STATUS;
 261                 iscsit_add_cmd_to_response_queue(cmd, conn, cmd->i_state);
 262                 return 0;
 263         }
 264
 265         /*
 266          * Special case to deal with DataSequenceInOrder=No and Non-Immeidate
 267          * Unsolicited DataOut.
 268          */
 269         if (cmd->unsolicited_data) {
 270                 cmd->unsolicited_data = 0;
 271
 272                 offset = cmd->next_burst_len = cmd->write_data_done;
 273
 274                 if ((conn->sess->sess_ops->FirstBurstLength - offset) >=
 275                      cmd->data_length) {
 276                         no_build_r2ts = 1;
 277                         length = (cmd->data_length - offset);
 278                 } else
 279                         length = (conn->sess->sess_ops->FirstBurstLength - offset);
 280
 281                 spin_lock_bh(&cmd->r2t_lock);
 282                 if (iscsit_add_r2t_to_list(cmd, offset, length, 0, 0) < 0) {
 283                         spin_unlock_bh(&cmd->r2t_lock);
 284                         return -1;
 285                 }
 286                 cmd->outstanding_r2ts++;
 287                 spin_unlock_bh(&cmd->r2t_lock);
 288
 289                 if (no_build_r2ts)
 290                         return 0;
 291         }
 292         /*
 293          * iscsit_build_r2ts_for_cmd() can handle the rest from here.
 294          */
 295         return iscsit_build_r2ts_for_cmd(cmd, conn, 2);
 296 }
 297
 298 static int iscsit_task_reassign_complete_read(
 299         struct iscsi_cmd *cmd,
 300         struct iscsi_tmr_req *tmr_req)
 301 {
 302         struct iscsi_conn *conn = cmd->conn;
 303         struct iscsi_datain_req *dr;
 304         struct se_cmd *se_cmd = &cmd->se_cmd;
 305         /*
 306          * The Initiator must not send a Data SNACK with a BegRun less than
 307          * the TMR TASK_REASSIGN's ExpDataSN.
 308          */
 309         if (!tmr_req->exp_data_sn) {
 310                 cmd->cmd_flags &= ~ICF_GOT_DATACK_SNACK;
 311                 cmd->acked_data_sn = 0;
 312         } else {
 313                 cmd->cmd_flags |= ICF_GOT_DATACK_SNACK;
 314                 cmd->acked_data_sn = (tmr_req->exp_data_sn - 1);
 315         }
 316
 317         if (!atomic_read(&cmd->transport_sent)) {
 318                 pr_debug("READ ITT: 0x%08x: t_state: %d never sent to"
 319                         " transport\n", cmd->init_task_tag,
 320                         cmd->se_cmd.t_state);
 321                 transport_generic_handle_cdb(se_cmd);
 322                 return 0;
 323         }
 324
 325         if (!atomic_read(&se_cmd->t_transport_complete)) {
 326                 pr_err("READ ITT: 0x%08x: t_state: %d, never returned"
 327                         " from transport\n", cmd->init_task_tag,
 328                         cmd->se_cmd.t_state);
 329                 return -1;
 330         }
 331
 332         dr = iscsit_allocate_datain_req();
 333         if (!dr)
 334                 return -1;
 335         /*
 336          * The TMR TASK_REASSIGN's ExpDataSN contains the next DataSN the
 337          * Initiator is expecting.
 338          */
 339         dr->data_sn = dr->begrun = tmr_req->exp_data_sn;
 340         dr->runlength = 0;
 341         dr->generate_recovery_values = 1;
 342         dr->recovery = DATAIN_CONNECTION_RECOVERY;
 343
 344         iscsit_attach_datain_req(cmd, dr);
 345
 346         cmd->i_state = ISTATE_SEND_DATAIN;
 347         iscsit_add_cmd_to_response_queue(cmd, conn, cmd->i_state);
 348         return 0;
 349 }
 350
 351 static int iscsit_task_reassign_complete_none(
 352         struct iscsi_cmd *cmd,
 353         struct iscsi_tmr_req *tmr_req)
 354 {
 355         struct iscsi_conn *conn = cmd->conn;
 356
 357         cmd->i_state = ISTATE_SEND_STATUS;
 358         iscsit_add_cmd_to_response_queue(cmd, conn, cmd->i_state);
 359         return 0;
 360 }
 361
 362 static int iscsit_task_reassign_complete_scsi_cmnd(
 363         struct iscsi_tmr_req *tmr_req,
 364         struct iscsi_conn *conn)
 365 {
 366         struct se_tmr_req *se_tmr = tmr_req->se_tmr_req;
 367         struct se_cmd *se_cmd = se_tmr->ref_cmd;
 368         struct iscsi_cmd *cmd = container_of(se_cmd, struct iscsi_cmd, se_cmd);
 369         struct iscsi_conn_recovery *cr;
 370
 371         if (!cmd->cr) {
 372                 pr_err("struct iscsi_conn_recovery pointer for ITT: 0x%08x"
 373                         " is NULL!\n", cmd->init_task_tag);
 374                 return -1;
 375         }
 376         cr = cmd->cr;
 377
 378         /*
 379          * Reset the StatSN so a new one for this commands new connection
 380          * will be assigned.
 381          * Reset the ExpStatSN as well so we may receive Status SNACKs.
 382          */
 383         cmd->stat_sn = cmd->exp_stat_sn = 0;
 384
 385         iscsit_task_reassign_remove_cmd(cmd, cr, conn->sess);
 386
 387         spin_lock_bh(&conn->cmd_lock);
 388         list_add_tail(&cmd->i_list, &conn->conn_cmd_list);
 389         spin_unlock_bh(&conn->cmd_lock);
 390
 391         if (se_cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION) {
 392                 cmd->i_state = ISTATE_SEND_STATUS;
 393                 iscsit_add_cmd_to_response_queue(cmd, conn, cmd->i_state);
 394                 return 0;
 395         }
 396
 397         switch (cmd->data_direction) {
 398         case DMA_TO_DEVICE:
 399                 return iscsit_task_reassign_complete_write(cmd, tmr_req);
 400         case DMA_FROM_DEVICE:
 401                 return iscsit_task_reassign_complete_read(cmd, tmr_req);
 402         case DMA_NONE:
 403                 return iscsit_task_reassign_complete_none(cmd, tmr_req);
 404         default:
 405                 pr_err("Unknown cmd->data_direction: 0x%02x\n",
 406                                 cmd->data_direction);
 407                 return -1;
 408         }
 409
 410         return 0;
 411 }
 412
 413 static int iscsit_task_reassign_complete(
 414         struct iscsi_tmr_req *tmr_req,
 415         struct iscsi_conn *conn)
 416 {
 417         struct se_tmr_req *se_tmr = tmr_req->se_tmr_req;
 418         struct se_cmd *se_cmd;
 419         struct iscsi_cmd *cmd;
 420         int ret = 0;
 421
 422         if (!se_tmr->ref_cmd) {
 423                 pr_err("TMR Request is missing a RefCmd struct iscsi_cmd.\n");
 424                 return -1;
 425         }
 426         se_cmd = se_tmr->ref_cmd;
 427         cmd = container_of(se_cmd, struct iscsi_cmd, se_cmd);
 428
 429         cmd->conn = conn;
 430
 431         switch (cmd->iscsi_opcode) {
 432         case ISCSI_OP_NOOP_OUT:
 433                 ret = iscsit_task_reassign_complete_nop_out(tmr_req, conn);
 434                 break;
 435         case ISCSI_OP_SCSI_CMD:
 436                 ret = iscsit_task_reassign_complete_scsi_cmnd(tmr_req, conn);
 437                 break;
 438         default:
 439                  pr_err("Illegal iSCSI Opcode 0x%02x during"
 440                         " command realligence\n", cmd->iscsi_opcode);
 441                 return -1;
 442         }
 443
 444         if (ret != 0)
 445                 return ret;
 446
 447         pr_debug("Completed connection realligence for Opcode: 0x%02x,"
 448                 " ITT: 0x%08x to CID: %hu.\n", cmd->iscsi_opcode,
 449                         cmd->init_task_tag, conn->cid);
 450
 451         return 0;
 452 }
 453
 454 /*
 455  *      Handles special after-the-fact actions related to TMRs.
 456  *      Right now the only one that its really needed for is
 457  *      connection recovery releated TASK_REASSIGN.
 458  */
 459 extern int iscsit_tmr_post_handler(struct iscsi_cmd *cmd, struct iscsi_conn *conn)
 460 {
 461         struct iscsi_tmr_req *tmr_req = cmd->tmr_req;
 462         struct se_tmr_req *se_tmr = cmd->se_cmd.se_tmr_req;
 463
 464         if (tmr_req->task_reassign &&
 465            (se_tmr->response == ISCSI_TMF_RSP_COMPLETE))
 466                 return iscsit_task_reassign_complete(tmr_req, conn);
 467
 468         return 0;
 469 }
 470
 471 /*
 472  *      Nothing to do here, but leave it for good measure. :-)
 473  */
 474 int iscsit_task_reassign_prepare_read(
 475         struct iscsi_tmr_req *tmr_req,
 476         struct iscsi_conn *conn)
 477 {
 478         return 0;
 479 }
 480
 481 static void iscsit_task_reassign_prepare_unsolicited_dataout(
 482         struct iscsi_cmd *cmd,
 483         struct iscsi_conn *conn)
 484 {
 485         int i, j;
 486         struct iscsi_pdu *pdu = NULL;
 487         struct iscsi_seq *seq = NULL;
 488
 489         if (conn->sess->sess_ops->DataSequenceInOrder) {
 490                 cmd->data_sn = 0;
 491
 492                 if (cmd->immediate_data)
 493                         cmd->r2t_offset += (cmd->first_burst_len -
 494                                 cmd->seq_start_offset);
 495
 496                 if (conn->sess->sess_ops->DataPDUInOrder) {
 497                         cmd->write_data_done -= (cmd->immediate_data) ?
 498                                                 (cmd->first_burst_len -
 499                                                  cmd->seq_start_offset) :
 500                                                  cmd->first_burst_len;
 501                         cmd->first_burst_len = 0;
 502                         return;
 503                 }
 504
 505                 for (i = 0; i < cmd->pdu_count; i++) {
 506                         pdu = &cmd->pdu_list[i];
 507
 508                         if (pdu->status != ISCSI_PDU_RECEIVED_OK)
 509                                 continue;
 510
 511                         if ((pdu->offset >= cmd->seq_start_offset) &&
 512                            ((pdu->offset + pdu->length) <=
 513                              cmd->seq_end_offset)) {
 514                                 cmd->first_burst_len -= pdu->length;
 515                                 cmd->write_data_done -= pdu->length;
 516                                 pdu->status = ISCSI_PDU_NOT_RECEIVED;
 517                         }
 518                 }
 519         } else {
 520                 for (i = 0; i < cmd->seq_count; i++) {
 521                         seq = &cmd->seq_list[i];
 522
 523                         if (seq->type != SEQTYPE_UNSOLICITED)
 524                                 continue;
 525
 526                         cmd->write_data_done -=
 527                                         (seq->offset - seq->orig_offset);
 528                         cmd->first_burst_len = 0;
 529                         seq->data_sn = 0;
 530                         seq->offset = seq->orig_offset;
 531                         seq->next_burst_len = 0;
 532                         seq->status = DATAOUT_SEQUENCE_WITHIN_COMMAND_RECOVERY;
 533
 534                         if (conn->sess->sess_ops->DataPDUInOrder)
 535                                 continue;
 536
 537                         for (j = 0; j < seq->pdu_count; j++) {
 538                                 pdu = &cmd->pdu_list[j+seq->pdu_start];
 539
 540                                 if (pdu->status != ISCSI_PDU_RECEIVED_OK)
 541                                         continue;
 542
 543                                 pdu->status = ISCSI_PDU_NOT_RECEIVED;
 544                         }
 545                 }
 546         }
 547 }
 548
 549 int iscsit_task_reassign_prepare_write(
 550         struct iscsi_tmr_req *tmr_req,
 551         struct iscsi_conn *conn)
 552 {
 553         struct se_tmr_req *se_tmr = tmr_req->se_tmr_req;
 554         struct se_cmd *se_cmd = se_tmr->ref_cmd;
 555         struct iscsi_cmd *cmd = container_of(se_cmd, struct iscsi_cmd, se_cmd);
 556         struct iscsi_pdu *pdu = NULL;
 557         struct iscsi_r2t *r2t = NULL, *r2t_tmp;
 558         int first_incomplete_r2t = 1, i = 0;
 559
 560         /*
 561          * The command was in the process of receiving Unsolicited DataOUT when
 562          * the connection failed.
 563          */
 564         if (cmd->unsolicited_data)
 565                 iscsit_task_reassign_prepare_unsolicited_dataout(cmd, conn);
 566
 567         /*
 568          * The Initiator is requesting R2Ts starting from zero,  skip
 569          * checking acknowledged R2Ts and start checking struct iscsi_r2ts
 570          * greater than zero.
 571          */
 572         if (!tmr_req->exp_data_sn)
 573                 goto drop_unacknowledged_r2ts;
 574
 575         /*
 576          * We now check that the PDUs in DataOUT sequences below
 577          * the TMR TASK_REASSIGN ExpDataSN (R2TSN the Initiator is
 578          * expecting next) have all the DataOUT they require to complete
 579          * the DataOUT sequence.  First scan from R2TSN 0 to TMR
 580          * TASK_REASSIGN ExpDataSN-1.
 581          *
 582          * If we have not received all DataOUT in question,  we must
 583          * make sure to make the appropriate changes to values in
 584          * struct iscsi_cmd (and elsewhere depending on session parameters)
 585          * so iscsit_build_r2ts_for_cmd() in iscsit_task_reassign_complete_write()
 586          * will resend a new R2T for the DataOUT sequences in question.
 587          */
 588         spin_lock_bh(&cmd->r2t_lock);
 589         if (list_empty(&cmd->cmd_r2t_list)) {
 590                 spin_unlock_bh(&cmd->r2t_lock);
 591                 return -1;
 592         }
 593
 594         list_for_each_entry(r2t, &cmd->cmd_r2t_list, r2t_list) {
 595
 596                 if (r2t->r2t_sn >= tmr_req->exp_data_sn)
 597                         continue;
 598                 /*
 599                  * Safely ignore Recovery R2Ts and R2Ts that have completed
 600                  * DataOUT sequences.
 601                  */
 602                 if (r2t->seq_complete)
 603                         continue;
 604
 605                 if (r2t->recovery_r2t)
 606                         continue;
 607
 608                 /*
 609                  *                 DataSequenceInOrder=Yes:
 610                  *
 611                  * Taking into account the iSCSI implementation requirement of
 612                  * MaxOutstandingR2T=1 while ErrorRecoveryLevel>0 and
 613                  * DataSequenceInOrder=Yes, we must take into consideration
 614                  * the following:
 615                  *
 616                  *                  DataSequenceInOrder=No:
 617                  *
 618                  * Taking into account that the Initiator controls the (possibly
 619                  * random) PDU Order in (possibly random) Sequence Order of
 620                  * DataOUT the target requests with R2Ts,  we must take into
 621                  * consideration the following:
 622                  *
 623                  *      DataPDUInOrder=Yes for DataSequenceInOrder=[Yes,No]:
 624                  *
 625                  * While processing non-complete R2T DataOUT sequence requests
 626                  * the Target will re-request only the total sequence length
 627                  * minus current received offset.  This is because we must
 628                  * assume the initiator will continue sending DataOUT from the
 629                  * last PDU before the connection failed.
 630                  *
 631                  *      DataPDUInOrder=No for DataSequenceInOrder=[Yes,No]:
 632                  *
 633                  * While processing non-complete R2T DataOUT sequence requests
 634                  * the Target will re-request the entire DataOUT sequence if
 635                  * any single PDU is missing from the sequence.  This is because
 636                  * we have no logical method to determine the next PDU offset,
 637                  * and we must assume the Initiator will be sending any random
 638                  * PDU offset in the current sequence after TASK_REASSIGN
 639                  * has completed.
 640                  */
 641                 if (conn->sess->sess_ops->DataSequenceInOrder) {
 642                         if (!first_incomplete_r2t) {
 643                                 cmd->r2t_offset -= r2t->xfer_len;
 644                                 goto next;
 645                         }
 646
 647                         if (conn->sess->sess_ops->DataPDUInOrder) {
 648                                 cmd->data_sn = 0;
 649                                 cmd->r2t_offset -= (r2t->xfer_len -
 650                                         cmd->next_burst_len);
 651                                 first_incomplete_r2t = 0;
 652                                 goto next;
 653                         }
 654
 655                         cmd->data_sn = 0;
 656                         cmd->r2t_offset -= r2t->xfer_len;
 657
 658                         for (i = 0; i < cmd->pdu_count; i++) {
 659                                 pdu = &cmd->pdu_list[i];
 660
 661                                 if (pdu->status != ISCSI_PDU_RECEIVED_OK)
 662                                         continue;
 663
 664                                 if ((pdu->offset >= r2t->offset) &&
 665                                     (pdu->offset < (r2t->offset +
 666                                                 r2t->xfer_len))) {
 667                                         cmd->next_burst_len -= pdu->length;
 668                                         cmd->write_data_done -= pdu->length;
 669                                         pdu->status = ISCSI_PDU_NOT_RECEIVED;
 670                                 }
 671                         }
 672
 673                         first_incomplete_r2t = 0;
 674                 } else {
 675                         struct iscsi_seq *seq;
 676
 677                         seq = iscsit_get_seq_holder(cmd, r2t->offset,
 678                                         r2t->xfer_len);
 679                         if (!seq) {
 680                                 spin_unlock_bh(&cmd->r2t_lock);
 681                                 return -1;
 682                         }
 683
 684                         cmd->write_data_done -=
 685                                         (seq->offset - seq->orig_offset);
 686                         seq->data_sn = 0;
 687                         seq->offset = seq->orig_offset;
 688                         seq->next_burst_len = 0;
 689                         seq->status = DATAOUT_SEQUENCE_WITHIN_COMMAND_RECOVERY;
 690
 691                         cmd->seq_send_order--;
 692
 693                         if (conn->sess->sess_ops->DataPDUInOrder)
 694                                 goto next;
 695
 696                         for (i = 0; i < seq->pdu_count; i++) {
 697                                 pdu = &cmd->pdu_list[i+seq->pdu_start];
 698
 699                                 if (pdu->status != ISCSI_PDU_RECEIVED_OK)
 700                                         continue;
 701
 702                                 pdu->status = ISCSI_PDU_NOT_RECEIVED;
 703                         }
 704                 }
 705
 706 next:
 707                 cmd->outstanding_r2ts--;
 708         }
 709         spin_unlock_bh(&cmd->r2t_lock);
 710
 711         /*
 712          * We now drop all unacknowledged R2Ts, ie: ExpDataSN from TMR
 713          * TASK_REASSIGN to the last R2T in the list..  We are also careful
 714          * to check that the Initiator is not requesting R2Ts for DataOUT
 715          * sequences it has already completed.
 716          *
 717          * Free each R2T in question and adjust values in struct iscsi_cmd
 718          * accordingly so iscsit_build_r2ts_for_cmd() do the rest of
 719          * the work after the TMR TASK_REASSIGN Response is sent.
 720          */
 721 drop_unacknowledged_r2ts:
 722
 723         cmd->cmd_flags &= ~ICF_SENT_LAST_R2T;
 724         cmd->r2t_sn = tmr_req->exp_data_sn;
 725
 726         spin_lock_bh(&cmd->r2t_lock);
 727         list_for_each_entry_safe(r2t, r2t_tmp, &cmd->cmd_r2t_list, r2t_list) {
 728                 /*
 729                  * Skip up to the R2T Sequence number provided by the
 730                  * iSCSI TASK_REASSIGN TMR
 731                  */
 732                 if (r2t->r2t_sn < tmr_req->exp_data_sn)
 733                         continue;
 734
 735                 if (r2t->seq_complete) {
 736                         pr_err("Initiator is requesting R2Ts from"
 737                                 " R2TSN: 0x%08x, but R2TSN: 0x%08x, Offset: %u,"
 738                                 " Length: %u is already complete."
 739                                 "   BAD INITIATOR ERL=2 IMPLEMENTATION!\n",
 740                                 tmr_req->exp_data_sn, r2t->r2t_sn,
 741                                 r2t->offset, r2t->xfer_len);
 742                         spin_unlock_bh(&cmd->r2t_lock);
 743                         return -1;
 744                 }
 745
 746                 if (r2t->recovery_r2t) {
 747                         iscsit_free_r2t(r2t, cmd);
 748                         continue;
 749                 }
 750
 751                 /*                 DataSequenceInOrder=Yes:
 752                  *
 753                  * Taking into account the iSCSI implementation requirement of
 754                  * MaxOutstandingR2T=1 while ErrorRecoveryLevel>0 and
 755                  * DataSequenceInOrder=Yes, it's safe to subtract the R2Ts
 756                  * entire transfer length from the commands R2T offset marker.
 757                  *
 758                  *                 DataSequenceInOrder=No:
 759                  *
 760                  * We subtract the difference from struct iscsi_seq between the
 761                  * current offset and original offset from cmd->write_data_done
 762                  * for account for DataOUT PDUs already received.  Then reset
 763                  * the current offset to the original and zero out the current
 764                  * burst length,  to make sure we re-request the entire DataOUT
 765                  * sequence.
 766                  */
 767                 if (conn->sess->sess_ops->DataSequenceInOrder)
 768                         cmd->r2t_offset -= r2t->xfer_len;
 769                 else
 770                         cmd->seq_send_order--;
 771
 772                 cmd->outstanding_r2ts--;
 773                 iscsit_free_r2t(r2t, cmd);
 774         }
 775         spin_unlock_bh(&cmd->r2t_lock);
 776
 777         return 0;
 778 }
 779
 780 /*
 781  *      Performs sanity checks TMR TASK_REASSIGN's ExpDataSN for
 782  *      a given struct iscsi_cmd.
 783  */
 784 int iscsit_check_task_reassign_expdatasn(
 785         struct iscsi_tmr_req *tmr_req,
 786         struct iscsi_conn *conn)
 787 {
 788         struct se_tmr_req *se_tmr = tmr_req->se_tmr_req;
 789         struct se_cmd *se_cmd = se_tmr->ref_cmd;
 790         struct iscsi_cmd *ref_cmd = container_of(se_cmd, struct iscsi_cmd, se_cmd);
 791
 792         if (ref_cmd->iscsi_opcode != ISCSI_OP_SCSI_CMD)
 793                 return 0;
 794
 795         if (se_cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION)
 796                 return 0;
 797
 798         if (ref_cmd->data_direction == DMA_NONE)
 799                 return 0;
 800
 801         /*
 802          * For READs the TMR TASK_REASSIGNs ExpDataSN contains the next DataSN
 803          * of DataIN the Initiator is expecting.
 804          *
 805          * Also check that the Initiator is not re-requesting DataIN that has
 806          * already been acknowledged with a DataAck SNACK.
 807          */
 808         if (ref_cmd->data_direction == DMA_FROM_DEVICE) {
 809                 if (tmr_req->exp_data_sn > ref_cmd->data_sn) {
 810                         pr_err("Received ExpDataSN: 0x%08x for READ"
 811                                 " in TMR TASK_REASSIGN greater than command's"
 812                                 " DataSN: 0x%08x.\n", tmr_req->exp_data_sn,
 813                                 ref_cmd->data_sn);
 814                         return -1;
 815                 }
 816                 if ((ref_cmd->cmd_flags & ICF_GOT_DATACK_SNACK) &&
 817                     (tmr_req->exp_data_sn <= ref_cmd->acked_data_sn)) {
 818                         pr_err("Received ExpDataSN: 0x%08x for READ"
 819                                 " in TMR TASK_REASSIGN for previously"
 820                                 " acknowledged DataIN: 0x%08x,"
 821                                 " protocol error\n", tmr_req->exp_data_sn,
 822                                 ref_cmd->acked_data_sn);
 823                         return -1;
 824                 }
 825                 return iscsit_task_reassign_prepare_read(tmr_req, conn);
 826         }
 827
 828         /*
 829          * For WRITEs the TMR TASK_REASSIGNs ExpDataSN contains the next R2TSN
 830          * for R2Ts the Initiator is expecting.
 831          *
 832          * Do the magic in iscsit_task_reassign_prepare_write().
 833          */
 834         if (ref_cmd->data_direction == DMA_TO_DEVICE) {
 835                 if (tmr_req->exp_data_sn > ref_cmd->r2t_sn) {
 836                         pr_err("Received ExpDataSN: 0x%08x for WRITE"
 837                                 " in TMR TASK_REASSIGN greater than command's"
 838                                 " R2TSN: 0x%08x.\n", tmr_req->exp_data_sn,
 839                                         ref_cmd->r2t_sn);
 840                         return -1;
 841                 }
 842                 return iscsit_task_reassign_prepare_write(tmr_req, conn);
 843         }
 844
 845         pr_err("Unknown iSCSI data_direction: 0x%02x\n",
 846                         ref_cmd->data_direction);
 847
 848         return -1;
 849 }