git.oblomov.eu Git - linux-2.6/blob - drivers/scsi/iscsi_tcp.c

   1 /*
   2  * iSCSI Initiator over TCP/IP Data-Path
   3  *
   4  * Copyright (C) 2004 Dmitry Yusupov
   5  * Copyright (C) 2004 Alex Aizman
   6  * Copyright (C) 2005 - 2006 Mike Christie
   7  * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
   8  * maintained by open-iscsi@googlegroups.com
   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
  12  * by 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, but
  16  * WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  18  * General Public License for more details.
  19  *
  20  * See the file COPYING included with this distribution for more details.
  21  *
  22  * Credits:
  23  *      Christoph Hellwig
  24  *      FUJITA Tomonori
  25  *      Arne Redlich
  26  *      Zhenyu Wang
  27  */
  28
  29 #include <linux/types.h>
  30 #include <linux/list.h>
  31 #include <linux/inet.h>
  32 #include <linux/file.h>
  33 #include <linux/blkdev.h>
  34 #include <linux/crypto.h>
  35 #include <linux/delay.h>
  36 #include <linux/kfifo.h>
  37 #include <linux/scatterlist.h>
  38 #include <net/tcp.h>
  39 #include <scsi/scsi_cmnd.h>
  40 #include <scsi/scsi_device.h>
  41 #include <scsi/scsi_host.h>
  42 #include <scsi/scsi.h>
  43 #include <scsi/scsi_transport_iscsi.h>
  44
  45 #include "iscsi_tcp.h"
  46
  47 MODULE_AUTHOR("Dmitry Yusupov <dmitry_yus@yahoo.com>, "
  48               "Alex Aizman <itn780@yahoo.com>");
  49 MODULE_DESCRIPTION("iSCSI/TCP data-path");
  50 MODULE_LICENSE("GPL");
  51 /* #define DEBUG_TCP */
  52 #define DEBUG_ASSERT
  53
  54 #ifdef DEBUG_TCP
  55 #define debug_tcp(fmt...) printk(KERN_INFO "tcp: " fmt)
  56 #else
  57 #define debug_tcp(fmt...)
  58 #endif
  59
  60 #ifndef DEBUG_ASSERT
  61 #ifdef BUG_ON
  62 #undef BUG_ON
  63 #endif
  64 #define BUG_ON(expr)
  65 #endif
  66
  67 static unsigned int iscsi_max_lun = 512;
  68 module_param_named(max_lun, iscsi_max_lun, uint, S_IRUGO);
  69
  70 static inline void
  71 iscsi_buf_init_iov(struct iscsi_buf *ibuf, char *vbuf, int size)
  72 {
  73         sg_init_one(&ibuf->sg, vbuf, size);
  74         ibuf->sent = 0;
  75         ibuf->use_sendmsg = 1;
  76 }
  77
  78 static inline void
  79 iscsi_buf_init_sg(struct iscsi_buf *ibuf, struct scatterlist *sg)
  80 {
  81         sg_init_table(&ibuf->sg, 1);
  82         sg_set_page(&ibuf->sg, sg_page(sg), sg->length, sg->offset);
  83         /*
  84          * Fastpath: sg element fits into single page
  85          */
  86         if (sg->length + sg->offset <= PAGE_SIZE && !PageSlab(sg_page(sg)))
  87                 ibuf->use_sendmsg = 0;
  88         else
  89                 ibuf->use_sendmsg = 1;
  90         ibuf->sent = 0;
  91 }
  92
  93 static inline int
  94 iscsi_buf_left(struct iscsi_buf *ibuf)
  95 {
  96         int rc;
  97
  98         rc = ibuf->sg.length - ibuf->sent;
  99         BUG_ON(rc < 0);
 100         return rc;
 101 }
 102
 103 static inline void
 104 iscsi_hdr_digest(struct iscsi_conn *conn, struct iscsi_buf *buf,
 105                  u8* crc)
 106 {
 107         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 108
 109         crypto_hash_digest(&tcp_conn->tx_hash, &buf->sg, buf->sg.length, crc);
 110         buf->sg.length += sizeof(u32);
 111 }
 112
 113 static inline int
 114 iscsi_hdr_extract(struct iscsi_tcp_conn *tcp_conn)
 115 {
 116         struct sk_buff *skb = tcp_conn->in.skb;
 117
 118         tcp_conn->in.zero_copy_hdr = 0;
 119
 120         if (tcp_conn->in.copy >= tcp_conn->hdr_size &&
 121             tcp_conn->in_progress == IN_PROGRESS_WAIT_HEADER) {
 122                 /*
 123                  * Zero-copy PDU Header: using connection context
 124                  * to store header pointer.
 125                  */
 126                 if (skb_shinfo(skb)->frag_list == NULL &&
 127                     !skb_shinfo(skb)->nr_frags) {
 128                         tcp_conn->in.hdr = (struct iscsi_hdr *)
 129                                 ((char*)skb->data + tcp_conn->in.offset);
 130                         tcp_conn->in.zero_copy_hdr = 1;
 131                 } else {
 132                         /* ignoring return code since we checked
 133                          * in.copy before */
 134                         skb_copy_bits(skb, tcp_conn->in.offset,
 135                                 &tcp_conn->hdr, tcp_conn->hdr_size);
 136                         tcp_conn->in.hdr = &tcp_conn->hdr;
 137                 }
 138                 tcp_conn->in.offset += tcp_conn->hdr_size;
 139                 tcp_conn->in.copy -= tcp_conn->hdr_size;
 140         } else {
 141                 int hdr_remains;
 142                 int copylen;
 143
 144                 /*
 145                  * PDU header scattered across SKB's,
 146                  * copying it... This'll happen quite rarely.
 147                  */
 148
 149                 if (tcp_conn->in_progress == IN_PROGRESS_WAIT_HEADER)
 150                         tcp_conn->in.hdr_offset = 0;
 151
 152                 hdr_remains = tcp_conn->hdr_size - tcp_conn->in.hdr_offset;
 153                 BUG_ON(hdr_remains <= 0);
 154
 155                 copylen = min(tcp_conn->in.copy, hdr_remains);
 156                 skb_copy_bits(skb, tcp_conn->in.offset,
 157                         (char*)&tcp_conn->hdr + tcp_conn->in.hdr_offset,
 158                         copylen);
 159
 160                 debug_tcp("PDU gather offset %d bytes %d in.offset %d "
 161                        "in.copy %d\n", tcp_conn->in.hdr_offset, copylen,
 162                        tcp_conn->in.offset, tcp_conn->in.copy);
 163
 164                 tcp_conn->in.offset += copylen;
 165                 tcp_conn->in.copy -= copylen;
 166                 if (copylen < hdr_remains)  {
 167                         tcp_conn->in_progress = IN_PROGRESS_HEADER_GATHER;
 168                         tcp_conn->in.hdr_offset += copylen;
 169                         return -EAGAIN;
 170                 }
 171                 tcp_conn->in.hdr = &tcp_conn->hdr;
 172                 tcp_conn->discontiguous_hdr_cnt++;
 173                 tcp_conn->in_progress = IN_PROGRESS_WAIT_HEADER;
 174         }
 175
 176         return 0;
 177 }
 178
 179 /*
 180  * must be called with session lock
 181  */
 182 static void
 183 iscsi_tcp_cleanup_ctask(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
 184 {
 185         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
 186         struct iscsi_r2t_info *r2t;
 187         struct scsi_cmnd *sc;
 188
 189         /* flush ctask's r2t queues */
 190         while (__kfifo_get(tcp_ctask->r2tqueue, (void*)&r2t, sizeof(void*))) {
 191                 __kfifo_put(tcp_ctask->r2tpool.queue, (void*)&r2t,
 192                             sizeof(void*));
 193                 debug_scsi("iscsi_tcp_cleanup_ctask pending r2t dropped\n");
 194         }
 195
 196         sc = ctask->sc;
 197         if (unlikely(!sc))
 198                 return;
 199
 200         tcp_ctask->xmstate = XMSTATE_IDLE;
 201         tcp_ctask->r2t = NULL;
 202 }
 203
 204 /**
 205  * iscsi_data_rsp - SCSI Data-In Response processing
 206  * @conn: iscsi connection
 207  * @ctask: scsi command task
 208  **/
 209 static int
 210 iscsi_data_rsp(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
 211 {
 212         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 213         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
 214         struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)tcp_conn->in.hdr;
 215         struct iscsi_session *session = conn->session;
 216         struct scsi_cmnd *sc = ctask->sc;
 217         int datasn = be32_to_cpu(rhdr->datasn);
 218
 219         iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr);
 220         /*
 221          * setup Data-In byte counter (gets decremented..)
 222          */
 223         ctask->data_count = tcp_conn->in.datalen;
 224
 225         if (tcp_conn->in.datalen == 0)
 226                 return 0;
 227
 228         if (tcp_ctask->exp_datasn != datasn) {
 229                 debug_tcp("%s: ctask->exp_datasn(%d) != rhdr->datasn(%d)\n",
 230                           __FUNCTION__, tcp_ctask->exp_datasn, datasn);
 231                 return ISCSI_ERR_DATASN;
 232         }
 233
 234         tcp_ctask->exp_datasn++;
 235
 236         tcp_ctask->data_offset = be32_to_cpu(rhdr->offset);
 237         if (tcp_ctask->data_offset + tcp_conn->in.datalen > scsi_bufflen(sc)) {
 238                 debug_tcp("%s: data_offset(%d) + data_len(%d) > total_length_in(%d)\n",
 239                           __FUNCTION__, tcp_ctask->data_offset,
 240                           tcp_conn->in.datalen, scsi_bufflen(sc));
 241                 return ISCSI_ERR_DATA_OFFSET;
 242         }
 243
 244         if (rhdr->flags & ISCSI_FLAG_DATA_STATUS) {
 245                 conn->exp_statsn = be32_to_cpu(rhdr->statsn) + 1;
 246                 if (rhdr->flags & ISCSI_FLAG_DATA_UNDERFLOW) {
 247                         int res_count = be32_to_cpu(rhdr->residual_count);
 248
 249                         if (res_count > 0 &&
 250                             res_count <= scsi_bufflen(sc)) {
 251                                 scsi_set_resid(sc, res_count);
 252                                 sc->result = (DID_OK << 16) | rhdr->cmd_status;
 253                         } else
 254                                 sc->result = (DID_BAD_TARGET << 16) |
 255                                         rhdr->cmd_status;
 256                 } else if (rhdr->flags & ISCSI_FLAG_DATA_OVERFLOW) {
 257                         scsi_set_resid(sc, be32_to_cpu(rhdr->residual_count));
 258                         sc->result = (DID_OK << 16) | rhdr->cmd_status;
 259                 } else
 260                         sc->result = (DID_OK << 16) | rhdr->cmd_status;
 261         }
 262
 263         conn->datain_pdus_cnt++;
 264         return 0;
 265 }
 266
 267 /**
 268  * iscsi_solicit_data_init - initialize first Data-Out
 269  * @conn: iscsi connection
 270  * @ctask: scsi command task
 271  * @r2t: R2T info
 272  *
 273  * Notes:
 274  *      Initialize first Data-Out within this R2T sequence and finds
 275  *      proper data_offset within this SCSI command.
 276  *
 277  *      This function is called with connection lock taken.
 278  **/
 279 static void
 280 iscsi_solicit_data_init(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
 281                         struct iscsi_r2t_info *r2t)
 282 {
 283         struct iscsi_data *hdr;
 284         struct scsi_cmnd *sc = ctask->sc;
 285         int i, sg_count = 0;
 286         struct scatterlist *sg;
 287
 288         hdr = &r2t->dtask.hdr;
 289         memset(hdr, 0, sizeof(struct iscsi_data));
 290         hdr->ttt = r2t->ttt;
 291         hdr->datasn = cpu_to_be32(r2t->solicit_datasn);
 292         r2t->solicit_datasn++;
 293         hdr->opcode = ISCSI_OP_SCSI_DATA_OUT;
 294         memcpy(hdr->lun, ctask->hdr->lun, sizeof(hdr->lun));
 295         hdr->itt = ctask->hdr->itt;
 296         hdr->exp_statsn = r2t->exp_statsn;
 297         hdr->offset = cpu_to_be32(r2t->data_offset);
 298         if (r2t->data_length > conn->max_xmit_dlength) {
 299                 hton24(hdr->dlength, conn->max_xmit_dlength);
 300                 r2t->data_count = conn->max_xmit_dlength;
 301                 hdr->flags = 0;
 302         } else {
 303                 hton24(hdr->dlength, r2t->data_length);
 304                 r2t->data_count = r2t->data_length;
 305                 hdr->flags = ISCSI_FLAG_CMD_FINAL;
 306         }
 307         conn->dataout_pdus_cnt++;
 308
 309         r2t->sent = 0;
 310
 311         iscsi_buf_init_iov(&r2t->headbuf, (char*)hdr,
 312                            sizeof(struct iscsi_hdr));
 313
 314         sg = scsi_sglist(sc);
 315         r2t->sg = NULL;
 316         for (i = 0; i < scsi_sg_count(sc); i++, sg += 1) {
 317                 /* FIXME: prefetch ? */
 318                 if (sg_count + sg->length > r2t->data_offset) {
 319                         int page_offset;
 320
 321                         /* sg page found! */
 322
 323                         /* offset within this page */
 324                         page_offset = r2t->data_offset - sg_count;
 325
 326                         /* fill in this buffer */
 327                         iscsi_buf_init_sg(&r2t->sendbuf, sg);
 328                         r2t->sendbuf.sg.offset += page_offset;
 329                         r2t->sendbuf.sg.length -= page_offset;
 330
 331                         /* xmit logic will continue with next one */
 332                         r2t->sg = sg + 1;
 333                         break;
 334                 }
 335                 sg_count += sg->length;
 336         }
 337         BUG_ON(r2t->sg == NULL);
 338 }
 339
 340 /**
 341  * iscsi_r2t_rsp - iSCSI R2T Response processing
 342  * @conn: iscsi connection
 343  * @ctask: scsi command task
 344  **/
 345 static int
 346 iscsi_r2t_rsp(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
 347 {
 348         struct iscsi_r2t_info *r2t;
 349         struct iscsi_session *session = conn->session;
 350         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
 351         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 352         struct iscsi_r2t_rsp *rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr;
 353         int r2tsn = be32_to_cpu(rhdr->r2tsn);
 354         int rc;
 355
 356         if (tcp_conn->in.datalen) {
 357                 printk(KERN_ERR "iscsi_tcp: invalid R2t with datalen %d\n",
 358                        tcp_conn->in.datalen);
 359                 return ISCSI_ERR_DATALEN;
 360         }
 361
 362         if (tcp_ctask->exp_datasn != r2tsn){
 363                 debug_tcp("%s: ctask->exp_datasn(%d) != rhdr->r2tsn(%d)\n",
 364                           __FUNCTION__, tcp_ctask->exp_datasn, r2tsn);
 365                 return ISCSI_ERR_R2TSN;
 366         }
 367
 368         /* fill-in new R2T associated with the task */
 369         spin_lock(&session->lock);
 370         iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr);
 371
 372         if (!ctask->sc || ctask->mtask ||
 373              session->state != ISCSI_STATE_LOGGED_IN) {
 374                 printk(KERN_INFO "iscsi_tcp: dropping R2T itt %d in "
 375                        "recovery...\n", ctask->itt);
 376                 spin_unlock(&session->lock);
 377                 return 0;
 378         }
 379
 380         rc = __kfifo_get(tcp_ctask->r2tpool.queue, (void*)&r2t, sizeof(void*));
 381         BUG_ON(!rc);
 382
 383         r2t->exp_statsn = rhdr->statsn;
 384         r2t->data_length = be32_to_cpu(rhdr->data_length);
 385         if (r2t->data_length == 0) {
 386                 printk(KERN_ERR "iscsi_tcp: invalid R2T with zero data len\n");
 387                 spin_unlock(&session->lock);
 388                 return ISCSI_ERR_DATALEN;
 389         }
 390
 391         if (r2t->data_length > session->max_burst)
 392                 debug_scsi("invalid R2T with data len %u and max burst %u."
 393                            "Attempting to execute request.\n",
 394                             r2t->data_length, session->max_burst);
 395
 396         r2t->data_offset = be32_to_cpu(rhdr->data_offset);
 397         if (r2t->data_offset + r2t->data_length > scsi_bufflen(ctask->sc)) {
 398                 spin_unlock(&session->lock);
 399                 printk(KERN_ERR "iscsi_tcp: invalid R2T with data len %u at "
 400                        "offset %u and total length %d\n", r2t->data_length,
 401                        r2t->data_offset, scsi_bufflen(ctask->sc));
 402                 return ISCSI_ERR_DATALEN;
 403         }
 404
 405         r2t->ttt = rhdr->ttt; /* no flip */
 406         r2t->solicit_datasn = 0;
 407
 408         iscsi_solicit_data_init(conn, ctask, r2t);
 409
 410         tcp_ctask->exp_datasn = r2tsn + 1;
 411         __kfifo_put(tcp_ctask->r2tqueue, (void*)&r2t, sizeof(void*));
 412         tcp_ctask->xmstate |= XMSTATE_SOL_HDR_INIT;
 413         list_move_tail(&ctask->running, &conn->xmitqueue);
 414
 415         scsi_queue_work(session->host, &conn->xmitwork);
 416         conn->r2t_pdus_cnt++;
 417         spin_unlock(&session->lock);
 418
 419         return 0;
 420 }
 421
 422 static int
 423 iscsi_tcp_hdr_recv(struct iscsi_conn *conn)
 424 {
 425         int rc = 0, opcode, ahslen;
 426         struct iscsi_hdr *hdr;
 427         struct iscsi_session *session = conn->session;
 428         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 429         uint32_t cdgst, rdgst = 0, itt;
 430
 431         hdr = tcp_conn->in.hdr;
 432
 433         /* verify PDU length */
 434         tcp_conn->in.datalen = ntoh24(hdr->dlength);
 435         if (tcp_conn->in.datalen > conn->max_recv_dlength) {
 436                 printk(KERN_ERR "iscsi_tcp: datalen %d > %d\n",
 437                        tcp_conn->in.datalen, conn->max_recv_dlength);
 438                 return ISCSI_ERR_DATALEN;
 439         }
 440         tcp_conn->data_copied = 0;
 441
 442         /* read AHS */
 443         ahslen = hdr->hlength << 2;
 444         tcp_conn->in.offset += ahslen;
 445         tcp_conn->in.copy -= ahslen;
 446         if (tcp_conn->in.copy < 0) {
 447                 printk(KERN_ERR "iscsi_tcp: can't handle AHS with length "
 448                        "%d bytes\n", ahslen);
 449                 return ISCSI_ERR_AHSLEN;
 450         }
 451
 452         /* calculate read padding */
 453         tcp_conn->in.padding = tcp_conn->in.datalen & (ISCSI_PAD_LEN-1);
 454         if (tcp_conn->in.padding) {
 455                 tcp_conn->in.padding = ISCSI_PAD_LEN - tcp_conn->in.padding;
 456                 debug_scsi("read padding %d bytes\n", tcp_conn->in.padding);
 457         }
 458
 459         if (conn->hdrdgst_en) {
 460                 struct scatterlist sg;
 461
 462                 sg_init_one(&sg, (u8 *)hdr,
 463                             sizeof(struct iscsi_hdr) + ahslen);
 464                 crypto_hash_digest(&tcp_conn->rx_hash, &sg, sg.length,
 465                                    (u8 *)&cdgst);
 466                 rdgst = *(uint32_t*)((char*)hdr + sizeof(struct iscsi_hdr) +
 467                                      ahslen);
 468                 if (cdgst != rdgst) {
 469                         printk(KERN_ERR "iscsi_tcp: hdrdgst error "
 470                                "recv 0x%x calc 0x%x\n", rdgst, cdgst);
 471                         return ISCSI_ERR_HDR_DGST;
 472                 }
 473         }
 474
 475         opcode = hdr->opcode & ISCSI_OPCODE_MASK;
 476         /* verify itt (itt encoding: age+cid+itt) */
 477         rc = iscsi_verify_itt(conn, hdr, &itt);
 478         if (rc == ISCSI_ERR_NO_SCSI_CMD) {
 479                 tcp_conn->in.datalen = 0; /* force drop */
 480                 return 0;
 481         } else if (rc)
 482                 return rc;
 483
 484         debug_tcp("opcode 0x%x offset %d copy %d ahslen %d datalen %d\n",
 485                   opcode, tcp_conn->in.offset, tcp_conn->in.copy,
 486                   ahslen, tcp_conn->in.datalen);
 487
 488         switch(opcode) {
 489         case ISCSI_OP_SCSI_DATA_IN:
 490                 tcp_conn->in.ctask = session->cmds[itt];
 491                 rc = iscsi_data_rsp(conn, tcp_conn->in.ctask);
 492                 if (rc)
 493                         return rc;
 494                 /* fall through */
 495         case ISCSI_OP_SCSI_CMD_RSP:
 496                 tcp_conn->in.ctask = session->cmds[itt];
 497                 if (tcp_conn->in.datalen)
 498                         goto copy_hdr;
 499
 500                 spin_lock(&session->lock);
 501                 rc = __iscsi_complete_pdu(conn, hdr, NULL, 0);
 502                 spin_unlock(&session->lock);
 503                 break;
 504         case ISCSI_OP_R2T:
 505                 tcp_conn->in.ctask = session->cmds[itt];
 506                 if (ahslen)
 507                         rc = ISCSI_ERR_AHSLEN;
 508                 else if (tcp_conn->in.ctask->sc->sc_data_direction ==
 509                                                                 DMA_TO_DEVICE)
 510                         rc = iscsi_r2t_rsp(conn, tcp_conn->in.ctask);
 511                 else
 512                         rc = ISCSI_ERR_PROTO;
 513                 break;
 514         case ISCSI_OP_LOGIN_RSP:
 515         case ISCSI_OP_TEXT_RSP:
 516         case ISCSI_OP_REJECT:
 517         case ISCSI_OP_ASYNC_EVENT:
 518                 /*
 519                  * It is possible that we could get a PDU with a buffer larger
 520                  * than 8K, but there are no targets that currently do this.
 521                  * For now we fail until we find a vendor that needs it
 522                  */
 523                 if (ISCSI_DEF_MAX_RECV_SEG_LEN <
 524                     tcp_conn->in.datalen) {
 525                         printk(KERN_ERR "iscsi_tcp: received buffer of len %u "
 526                               "but conn buffer is only %u (opcode %0x)\n",
 527                               tcp_conn->in.datalen,
 528                               ISCSI_DEF_MAX_RECV_SEG_LEN, opcode);
 529                         rc = ISCSI_ERR_PROTO;
 530                         break;
 531                 }
 532
 533                 if (tcp_conn->in.datalen)
 534                         goto copy_hdr;
 535         /* fall through */
 536         case ISCSI_OP_LOGOUT_RSP:
 537         case ISCSI_OP_NOOP_IN:
 538         case ISCSI_OP_SCSI_TMFUNC_RSP:
 539                 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
 540                 break;
 541         default:
 542                 rc = ISCSI_ERR_BAD_OPCODE;
 543                 break;
 544         }
 545
 546         return rc;
 547
 548 copy_hdr:
 549         /*
 550          * if we did zero copy for the header but we will need multiple
 551          * skbs to complete the command then we have to copy the header
 552          * for later use
 553          */
 554         if (tcp_conn->in.zero_copy_hdr && tcp_conn->in.copy <=
 555            (tcp_conn->in.datalen + tcp_conn->in.padding +
 556             (conn->datadgst_en ? 4 : 0))) {
 557                 debug_tcp("Copying header for later use. in.copy %d in.datalen"
 558                           " %d\n", tcp_conn->in.copy, tcp_conn->in.datalen);
 559                 memcpy(&tcp_conn->hdr, tcp_conn->in.hdr,
 560                        sizeof(struct iscsi_hdr));
 561                 tcp_conn->in.hdr = &tcp_conn->hdr;
 562                 tcp_conn->in.zero_copy_hdr = 0;
 563         }
 564         return 0;
 565 }
 566
 567 /**
 568  * iscsi_ctask_copy - copy skb bits to the destanation cmd task
 569  * @conn: iscsi tcp connection
 570  * @ctask: scsi command task
 571  * @buf: buffer to copy to
 572  * @buf_size: size of buffer
 573  * @offset: offset within the buffer
 574  *
 575  * Notes:
 576  *      The function calls skb_copy_bits() and updates per-connection and
 577  *      per-cmd byte counters.
 578  *
 579  *      Read counters (in bytes):
 580  *
 581  *      conn->in.offset         offset within in progress SKB
 582  *      conn->in.copy           left to copy from in progress SKB
 583  *                              including padding
 584  *      conn->in.copied         copied already from in progress SKB
 585  *      conn->data_copied       copied already from in progress buffer
 586  *      ctask->sent             total bytes sent up to the MidLayer
 587  *      ctask->data_count       left to copy from in progress Data-In
 588  *      buf_left                left to copy from in progress buffer
 589  **/
 590 static inline int
 591 iscsi_ctask_copy(struct iscsi_tcp_conn *tcp_conn, struct iscsi_cmd_task *ctask,
 592                 void *buf, int buf_size, int offset)
 593 {
 594         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
 595         int buf_left = buf_size - (tcp_conn->data_copied + offset);
 596         unsigned size = min(tcp_conn->in.copy, buf_left);
 597         int rc;
 598
 599         size = min(size, ctask->data_count);
 600
 601         debug_tcp("ctask_copy %d bytes at offset %d copied %d\n",
 602                size, tcp_conn->in.offset, tcp_conn->in.copied);
 603
 604         BUG_ON(size <= 0);
 605         BUG_ON(tcp_ctask->sent + size > scsi_bufflen(ctask->sc));
 606
 607         rc = skb_copy_bits(tcp_conn->in.skb, tcp_conn->in.offset,
 608                            (char*)buf + (offset + tcp_conn->data_copied), size);
 609         /* must fit into skb->len */
 610         BUG_ON(rc);
 611
 612         tcp_conn->in.offset += size;
 613         tcp_conn->in.copy -= size;
 614         tcp_conn->in.copied += size;
 615         tcp_conn->data_copied += size;
 616         tcp_ctask->sent += size;
 617         ctask->data_count -= size;
 618
 619         BUG_ON(tcp_conn->in.copy < 0);
 620         BUG_ON(ctask->data_count < 0);
 621
 622         if (buf_size != (tcp_conn->data_copied + offset)) {
 623                 if (!ctask->data_count) {
 624                         BUG_ON(buf_size - tcp_conn->data_copied < 0);
 625                         /* done with this PDU */
 626                         return buf_size - tcp_conn->data_copied;
 627                 }
 628                 return -EAGAIN;
 629         }
 630
 631         /* done with this buffer or with both - PDU and buffer */
 632         tcp_conn->data_copied = 0;
 633         return 0;
 634 }
 635
 636 /**
 637  * iscsi_tcp_copy - copy skb bits to the destanation buffer
 638  * @conn: iscsi tcp connection
 639  *
 640  * Notes:
 641  *      The function calls skb_copy_bits() and updates per-connection
 642  *      byte counters.
 643  **/
 644 static inline int
 645 iscsi_tcp_copy(struct iscsi_conn *conn, int buf_size)
 646 {
 647         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 648         int buf_left = buf_size - tcp_conn->data_copied;
 649         int size = min(tcp_conn->in.copy, buf_left);
 650         int rc;
 651
 652         debug_tcp("tcp_copy %d bytes at offset %d copied %d\n",
 653                size, tcp_conn->in.offset, tcp_conn->data_copied);
 654         BUG_ON(size <= 0);
 655
 656         rc = skb_copy_bits(tcp_conn->in.skb, tcp_conn->in.offset,
 657                            (char*)conn->data + tcp_conn->data_copied, size);
 658         BUG_ON(rc);
 659
 660         tcp_conn->in.offset += size;
 661         tcp_conn->in.copy -= size;
 662         tcp_conn->in.copied += size;
 663         tcp_conn->data_copied += size;
 664
 665         if (buf_size != tcp_conn->data_copied)
 666                 return -EAGAIN;
 667
 668         return 0;
 669 }
 670
 671 static inline void
 672 partial_sg_digest_update(struct hash_desc *desc, struct scatterlist *sg,
 673                          int offset, int length)
 674 {
 675         struct scatterlist temp;
 676
 677         sg_init_table(&temp, 1);
 678         sg_set_page(&temp, sg_page(sg), length, offset);
 679         crypto_hash_update(desc, &temp, length);
 680 }
 681
 682 static void
 683 iscsi_recv_digest_update(struct iscsi_tcp_conn *tcp_conn, char* buf, int len)
 684 {
 685         struct scatterlist tmp;
 686
 687         sg_init_one(&tmp, buf, len);
 688         crypto_hash_update(&tcp_conn->rx_hash, &tmp, len);
 689 }
 690
 691 static int iscsi_scsi_data_in(struct iscsi_conn *conn)
 692 {
 693         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 694         struct iscsi_cmd_task *ctask = tcp_conn->in.ctask;
 695         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
 696         struct scsi_cmnd *sc = ctask->sc;
 697         struct scatterlist *sg;
 698         int i, offset, rc = 0;
 699
 700         BUG_ON((void*)ctask != sc->SCp.ptr);
 701
 702         offset = tcp_ctask->data_offset;
 703         sg = scsi_sglist(sc);
 704
 705         if (tcp_ctask->data_offset)
 706                 for (i = 0; i < tcp_ctask->sg_count; i++)
 707                         offset -= sg[i].length;
 708         /* we've passed through partial sg*/
 709         if (offset < 0)
 710                 offset = 0;
 711
 712         for (i = tcp_ctask->sg_count; i < scsi_sg_count(sc); i++) {
 713                 char *dest;
 714
 715                 dest = kmap_atomic(sg_page(&sg[i]), KM_SOFTIRQ0);
 716                 rc = iscsi_ctask_copy(tcp_conn, ctask, dest + sg[i].offset,
 717                                       sg[i].length, offset);
 718                 kunmap_atomic(dest, KM_SOFTIRQ0);
 719                 if (rc == -EAGAIN)
 720                         /* continue with the next SKB/PDU */
 721                         return rc;
 722                 if (!rc) {
 723                         if (conn->datadgst_en) {
 724                                 if (!offset)
 725                                         crypto_hash_update(
 726                                                         &tcp_conn->rx_hash,
 727                                                         &sg[i], sg[i].length);
 728                                 else
 729                                         partial_sg_digest_update(
 730                                                         &tcp_conn->rx_hash,
 731                                                         &sg[i],
 732                                                         sg[i].offset + offset,
 733                                                         sg[i].length - offset);
 734                         }
 735                         offset = 0;
 736                         tcp_ctask->sg_count++;
 737                 }
 738
 739                 if (!ctask->data_count) {
 740                         if (rc && conn->datadgst_en)
 741                                 /*
 742                                  * data-in is complete, but buffer not...
 743                                  */
 744                                 partial_sg_digest_update(&tcp_conn->rx_hash,
 745                                                          &sg[i],
 746                                                          sg[i].offset,
 747                                                          sg[i].length-rc);
 748                         rc = 0;
 749                         break;
 750                 }
 751
 752                 if (!tcp_conn->in.copy)
 753                         return -EAGAIN;
 754         }
 755         BUG_ON(ctask->data_count);
 756
 757         /* check for non-exceptional status */
 758         if (tcp_conn->in.hdr->flags & ISCSI_FLAG_DATA_STATUS) {
 759                 debug_scsi("done [sc %lx res %d itt 0x%x flags 0x%x]\n",
 760                            (long)sc, sc->result, ctask->itt,
 761                            tcp_conn->in.hdr->flags);
 762                 spin_lock(&conn->session->lock);
 763                 __iscsi_complete_pdu(conn, tcp_conn->in.hdr, NULL, 0);
 764                 spin_unlock(&conn->session->lock);
 765         }
 766
 767         return rc;
 768 }
 769
 770 static int
 771 iscsi_data_recv(struct iscsi_conn *conn)
 772 {
 773         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 774         int rc = 0, opcode;
 775
 776         opcode = tcp_conn->in.hdr->opcode & ISCSI_OPCODE_MASK;
 777         switch (opcode) {
 778         case ISCSI_OP_SCSI_DATA_IN:
 779                 rc = iscsi_scsi_data_in(conn);
 780                 break;
 781         case ISCSI_OP_SCSI_CMD_RSP:
 782         case ISCSI_OP_TEXT_RSP:
 783         case ISCSI_OP_LOGIN_RSP:
 784         case ISCSI_OP_ASYNC_EVENT:
 785         case ISCSI_OP_REJECT:
 786                 /*
 787                  * Collect data segment to the connection's data
 788                  * placeholder
 789                  */
 790                 if (iscsi_tcp_copy(conn, tcp_conn->in.datalen)) {
 791                         rc = -EAGAIN;
 792                         goto exit;
 793                 }
 794
 795                 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, conn->data,
 796                                         tcp_conn->in.datalen);
 797                 if (!rc && conn->datadgst_en && opcode != ISCSI_OP_LOGIN_RSP)
 798                         iscsi_recv_digest_update(tcp_conn, conn->data,
 799                                                 tcp_conn->in.datalen);
 800                 break;
 801         default:
 802                 BUG_ON(1);
 803         }
 804 exit:
 805         return rc;
 806 }
 807
 808 /**
 809  * iscsi_tcp_data_recv - TCP receive in sendfile fashion
 810  * @rd_desc: read descriptor
 811  * @skb: socket buffer
 812  * @offset: offset in skb
 813  * @len: skb->len - offset
 814  **/
 815 static int
 816 iscsi_tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
 817                 unsigned int offset, size_t len)
 818 {
 819         int rc;
 820         struct iscsi_conn *conn = rd_desc->arg.data;
 821         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 822         int processed;
 823         char pad[ISCSI_PAD_LEN];
 824         struct scatterlist sg;
 825
 826         /*
 827          * Save current SKB and its offset in the corresponding
 828          * connection context.
 829          */
 830         tcp_conn->in.copy = skb->len - offset;
 831         tcp_conn->in.offset = offset;
 832         tcp_conn->in.skb = skb;
 833         tcp_conn->in.len = tcp_conn->in.copy;
 834         BUG_ON(tcp_conn->in.copy <= 0);
 835         debug_tcp("in %d bytes\n", tcp_conn->in.copy);
 836
 837 more:
 838         tcp_conn->in.copied = 0;
 839         rc = 0;
 840
 841         if (unlikely(conn->suspend_rx)) {
 842                 debug_tcp("conn %d Rx suspended!\n", conn->id);
 843                 return 0;
 844         }
 845
 846         if (tcp_conn->in_progress == IN_PROGRESS_WAIT_HEADER ||
 847             tcp_conn->in_progress == IN_PROGRESS_HEADER_GATHER) {
 848                 rc = iscsi_hdr_extract(tcp_conn);
 849                 if (rc) {
 850                        if (rc == -EAGAIN)
 851                                 goto nomore;
 852                        else {
 853                                 iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
 854                                 return 0;
 855                        }
 856                 }
 857
 858                 /*
 859                  * Verify and process incoming PDU header.
 860                  */
 861                 rc = iscsi_tcp_hdr_recv(conn);
 862                 if (!rc && tcp_conn->in.datalen) {
 863                         if (conn->datadgst_en)
 864                                 crypto_hash_init(&tcp_conn->rx_hash);
 865                         tcp_conn->in_progress = IN_PROGRESS_DATA_RECV;
 866                 } else if (rc) {
 867                         iscsi_conn_failure(conn, rc);
 868                         return 0;
 869                 }
 870         }
 871
 872         if (tcp_conn->in_progress == IN_PROGRESS_DDIGEST_RECV &&
 873             tcp_conn->in.copy) {
 874                 uint32_t recv_digest;
 875
 876                 debug_tcp("extra data_recv offset %d copy %d\n",
 877                           tcp_conn->in.offset, tcp_conn->in.copy);
 878
 879                 if (!tcp_conn->data_copied) {
 880                         if (tcp_conn->in.padding) {
 881                                 debug_tcp("padding -> %d\n",
 882                                           tcp_conn->in.padding);
 883                                 memset(pad, 0, tcp_conn->in.padding);
 884                                 sg_init_one(&sg, pad, tcp_conn->in.padding);
 885                                 crypto_hash_update(&tcp_conn->rx_hash,
 886                                                    &sg, sg.length);
 887                         }
 888                         crypto_hash_final(&tcp_conn->rx_hash,
 889                                           (u8 *) &tcp_conn->in.datadgst);
 890                         debug_tcp("rx digest 0x%x\n", tcp_conn->in.datadgst);
 891                 }
 892
 893                 rc = iscsi_tcp_copy(conn, sizeof(uint32_t));
 894                 if (rc) {
 895                         if (rc == -EAGAIN)
 896                                 goto again;
 897                         iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
 898                         return 0;
 899                 }
 900
 901                 memcpy(&recv_digest, conn->data, sizeof(uint32_t));
 902                 if (recv_digest != tcp_conn->in.datadgst) {
 903                         debug_tcp("iscsi_tcp: data digest error!"
 904                                   "0x%x != 0x%x\n", recv_digest,
 905                                   tcp_conn->in.datadgst);
 906                         iscsi_conn_failure(conn, ISCSI_ERR_DATA_DGST);
 907                         return 0;
 908                 } else {
 909                         debug_tcp("iscsi_tcp: data digest match!"
 910                                   "0x%x == 0x%x\n", recv_digest,
 911                                   tcp_conn->in.datadgst);
 912                         tcp_conn->in_progress = IN_PROGRESS_WAIT_HEADER;
 913                 }
 914         }
 915
 916         if (tcp_conn->in_progress == IN_PROGRESS_DATA_RECV &&
 917             tcp_conn->in.copy) {
 918                 debug_tcp("data_recv offset %d copy %d\n",
 919                        tcp_conn->in.offset, tcp_conn->in.copy);
 920
 921                 rc = iscsi_data_recv(conn);
 922                 if (rc) {
 923                         if (rc == -EAGAIN)
 924                                 goto again;
 925                         iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
 926                         return 0;
 927                 }
 928
 929                 if (tcp_conn->in.padding)
 930                         tcp_conn->in_progress = IN_PROGRESS_PAD_RECV;
 931                 else if (conn->datadgst_en)
 932                         tcp_conn->in_progress = IN_PROGRESS_DDIGEST_RECV;
 933                 else
 934                         tcp_conn->in_progress = IN_PROGRESS_WAIT_HEADER;
 935                 tcp_conn->data_copied = 0;
 936         }
 937
 938         if (tcp_conn->in_progress == IN_PROGRESS_PAD_RECV &&
 939             tcp_conn->in.copy) {
 940                 int copylen = min(tcp_conn->in.padding - tcp_conn->data_copied,
 941                                   tcp_conn->in.copy);
 942
 943                 tcp_conn->in.copy -= copylen;
 944                 tcp_conn->in.offset += copylen;
 945                 tcp_conn->data_copied += copylen;
 946
 947                 if (tcp_conn->data_copied != tcp_conn->in.padding)
 948                         tcp_conn->in_progress = IN_PROGRESS_PAD_RECV;
 949                 else if (conn->datadgst_en)
 950                         tcp_conn->in_progress = IN_PROGRESS_DDIGEST_RECV;
 951                 else
 952                         tcp_conn->in_progress = IN_PROGRESS_WAIT_HEADER;
 953                 tcp_conn->data_copied = 0;
 954         }
 955
 956         debug_tcp("f, processed %d from out of %d padding %d\n",
 957                tcp_conn->in.offset - offset, (int)len, tcp_conn->in.padding);
 958         BUG_ON(tcp_conn->in.offset - offset > len);
 959
 960         if (tcp_conn->in.offset - offset != len) {
 961                 debug_tcp("continue to process %d bytes\n",
 962                        (int)len - (tcp_conn->in.offset - offset));
 963                 goto more;
 964         }
 965
 966 nomore:
 967         processed = tcp_conn->in.offset - offset;
 968         BUG_ON(processed == 0);
 969         return processed;
 970
 971 again:
 972         processed = tcp_conn->in.offset - offset;
 973         debug_tcp("c, processed %d from out of %d rd_desc_cnt %d\n",
 974                   processed, (int)len, (int)rd_desc->count);
 975         BUG_ON(processed == 0);
 976         BUG_ON(processed > len);
 977
 978         conn->rxdata_octets += processed;
 979         return processed;
 980 }
 981
 982 static void
 983 iscsi_tcp_data_ready(struct sock *sk, int flag)
 984 {
 985         struct iscsi_conn *conn = sk->sk_user_data;
 986         read_descriptor_t rd_desc;
 987
 988         read_lock(&sk->sk_callback_lock);
 989
 990         /*
 991          * Use rd_desc to pass 'conn' to iscsi_tcp_data_recv.
 992          * We set count to 1 because we want the network layer to
 993          * hand us all the skbs that are available. iscsi_tcp_data_recv
 994          * handled pdus that cross buffers or pdus that still need data.
 995          */
 996         rd_desc.arg.data = conn;
 997         rd_desc.count = 1;
 998         tcp_read_sock(sk, &rd_desc, iscsi_tcp_data_recv);
 999
1000         read_unlock(&sk->sk_callback_lock);
1001 }
1002
1003 static void
1004 iscsi_tcp_state_change(struct sock *sk)
1005 {
1006         struct iscsi_tcp_conn *tcp_conn;
1007         struct iscsi_conn *conn;
1008         struct iscsi_session *session;
1009         void (*old_state_change)(struct sock *);
1010
1011         read_lock(&sk->sk_callback_lock);
1012
1013         conn = (struct iscsi_conn*)sk->sk_user_data;
1014         session = conn->session;
1015
1016         if ((sk->sk_state == TCP_CLOSE_WAIT ||
1017              sk->sk_state == TCP_CLOSE) &&
1018             !atomic_read(&sk->sk_rmem_alloc)) {
1019                 debug_tcp("iscsi_tcp_state_change: TCP_CLOSE|TCP_CLOSE_WAIT\n");
1020                 iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
1021         }
1022
1023         tcp_conn = conn->dd_data;
1024         old_state_change = tcp_conn->old_state_change;
1025
1026         read_unlock(&sk->sk_callback_lock);
1027
1028         old_state_change(sk);
1029 }
1030
1031 /**
1032  * iscsi_write_space - Called when more output buffer space is available
1033  * @sk: socket space is available for
1034  **/
1035 static void
1036 iscsi_write_space(struct sock *sk)
1037 {
1038         struct iscsi_conn *conn = (struct iscsi_conn*)sk->sk_user_data;
1039         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1040
1041         tcp_conn->old_write_space(sk);
1042         debug_tcp("iscsi_write_space: cid %d\n", conn->id);
1043         scsi_queue_work(conn->session->host, &conn->xmitwork);
1044 }
1045
1046 static void
1047 iscsi_conn_set_callbacks(struct iscsi_conn *conn)
1048 {
1049         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1050         struct sock *sk = tcp_conn->sock->sk;
1051
1052         /* assign new callbacks */
1053         write_lock_bh(&sk->sk_callback_lock);
1054         sk->sk_user_data = conn;
1055         tcp_conn->old_data_ready = sk->sk_data_ready;
1056         tcp_conn->old_state_change = sk->sk_state_change;
1057         tcp_conn->old_write_space = sk->sk_write_space;
1058         sk->sk_data_ready = iscsi_tcp_data_ready;
1059         sk->sk_state_change = iscsi_tcp_state_change;
1060         sk->sk_write_space = iscsi_write_space;
1061         write_unlock_bh(&sk->sk_callback_lock);
1062 }
1063
1064 static void
1065 iscsi_conn_restore_callbacks(struct iscsi_tcp_conn *tcp_conn)
1066 {
1067         struct sock *sk = tcp_conn->sock->sk;
1068
1069         /* restore socket callbacks, see also: iscsi_conn_set_callbacks() */
1070         write_lock_bh(&sk->sk_callback_lock);
1071         sk->sk_user_data    = NULL;
1072         sk->sk_data_ready   = tcp_conn->old_data_ready;
1073         sk->sk_state_change = tcp_conn->old_state_change;
1074         sk->sk_write_space  = tcp_conn->old_write_space;
1075         sk->sk_no_check  = 0;
1076         write_unlock_bh(&sk->sk_callback_lock);
1077 }
1078
1079 /**
1080  * iscsi_send - generic send routine
1081  * @sk: kernel's socket
1082  * @buf: buffer to write from
1083  * @size: actual size to write
1084  * @flags: socket's flags
1085  */
1086 static inline int
1087 iscsi_send(struct iscsi_conn *conn, struct iscsi_buf *buf, int size, int flags)
1088 {
1089         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1090         struct socket *sk = tcp_conn->sock;
1091         int offset = buf->sg.offset + buf->sent, res;
1092
1093         /*
1094          * if we got use_sg=0 or are sending something we kmallocd
1095          * then we did not have to do kmap (kmap returns page_address)
1096          *
1097          * if we got use_sg > 0, but had to drop down, we do not
1098          * set clustering so this should only happen for that
1099          * slab case.
1100          */
1101         if (buf->use_sendmsg)
1102                 res = sock_no_sendpage(sk, sg_page(&buf->sg), offset, size, flags);
1103         else
1104                 res = tcp_conn->sendpage(sk, sg_page(&buf->sg), offset, size, flags);
1105
1106         if (res >= 0) {
1107                 conn->txdata_octets += res;
1108                 buf->sent += res;
1109                 return res;
1110         }
1111
1112         tcp_conn->sendpage_failures_cnt++;
1113         if (res == -EAGAIN)
1114                 res = -ENOBUFS;
1115         else
1116                 iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
1117         return res;
1118 }
1119
1120 /**
1121  * iscsi_sendhdr - send PDU Header via tcp_sendpage()
1122  * @conn: iscsi connection
1123  * @buf: buffer to write from
1124  * @datalen: lenght of data to be sent after the header
1125  *
1126  * Notes:
1127  *      (Tx, Fast Path)
1128  **/
1129 static inline int
1130 iscsi_sendhdr(struct iscsi_conn *conn, struct iscsi_buf *buf, int datalen)
1131 {
1132         int flags = 0; /* MSG_DONTWAIT; */
1133         int res, size;
1134
1135         size = buf->sg.length - buf->sent;
1136         BUG_ON(buf->sent + size > buf->sg.length);
1137         if (buf->sent + size != buf->sg.length || datalen)
1138                 flags |= MSG_MORE;
1139
1140         res = iscsi_send(conn, buf, size, flags);
1141         debug_tcp("sendhdr %d bytes, sent %d res %d\n", size, buf->sent, res);
1142         if (res >= 0) {
1143                 if (size != res)
1144                         return -EAGAIN;
1145                 return 0;
1146         }
1147
1148         return res;
1149 }
1150
1151 /**
1152  * iscsi_sendpage - send one page of iSCSI Data-Out.
1153  * @conn: iscsi connection
1154  * @buf: buffer to write from
1155  * @count: remaining data
1156  * @sent: number of bytes sent
1157  *
1158  * Notes:
1159  *      (Tx, Fast Path)
1160  **/
1161 static inline int
1162 iscsi_sendpage(struct iscsi_conn *conn, struct iscsi_buf *buf,
1163                int *count, int *sent)
1164 {
1165         int flags = 0; /* MSG_DONTWAIT; */
1166         int res, size;
1167
1168         size = buf->sg.length - buf->sent;
1169         BUG_ON(buf->sent + size > buf->sg.length);
1170         if (size > *count)
1171                 size = *count;
1172         if (buf->sent + size != buf->sg.length || *count != size)
1173                 flags |= MSG_MORE;
1174
1175         res = iscsi_send(conn, buf, size, flags);
1176         debug_tcp("sendpage: %d bytes, sent %d left %d sent %d res %d\n",
1177                   size, buf->sent, *count, *sent, res);
1178         if (res >= 0) {
1179                 *count -= res;
1180                 *sent += res;
1181                 if (size != res)
1182                         return -EAGAIN;
1183                 return 0;
1184         }
1185
1186         return res;
1187 }
1188
1189 static inline void
1190 iscsi_data_digest_init(struct iscsi_tcp_conn *tcp_conn,
1191                       struct iscsi_tcp_cmd_task *tcp_ctask)
1192 {
1193         crypto_hash_init(&tcp_conn->tx_hash);
1194         tcp_ctask->digest_count = 4;
1195 }
1196
1197 /**
1198  * iscsi_solicit_data_cont - initialize next Data-Out
1199  * @conn: iscsi connection
1200  * @ctask: scsi command task
1201  * @r2t: R2T info
1202  * @left: bytes left to transfer
1203  *
1204  * Notes:
1205  *      Initialize next Data-Out within this R2T sequence and continue
1206  *      to process next Scatter-Gather element(if any) of this SCSI command.
1207  *
1208  *      Called under connection lock.
1209  **/
1210 static void
1211 iscsi_solicit_data_cont(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
1212                         struct iscsi_r2t_info *r2t, int left)
1213 {
1214         struct iscsi_data *hdr;
1215         int new_offset;
1216
1217         hdr = &r2t->dtask.hdr;
1218         memset(hdr, 0, sizeof(struct iscsi_data));
1219         hdr->ttt = r2t->ttt;
1220         hdr->datasn = cpu_to_be32(r2t->solicit_datasn);
1221         r2t->solicit_datasn++;
1222         hdr->opcode = ISCSI_OP_SCSI_DATA_OUT;
1223         memcpy(hdr->lun, ctask->hdr->lun, sizeof(hdr->lun));
1224         hdr->itt = ctask->hdr->itt;
1225         hdr->exp_statsn = r2t->exp_statsn;
1226         new_offset = r2t->data_offset + r2t->sent;
1227         hdr->offset = cpu_to_be32(new_offset);
1228         if (left > conn->max_xmit_dlength) {
1229                 hton24(hdr->dlength, conn->max_xmit_dlength);
1230                 r2t->data_count = conn->max_xmit_dlength;
1231         } else {
1232                 hton24(hdr->dlength, left);
1233                 r2t->data_count = left;
1234                 hdr->flags = ISCSI_FLAG_CMD_FINAL;
1235         }
1236         conn->dataout_pdus_cnt++;
1237
1238         iscsi_buf_init_iov(&r2t->headbuf, (char*)hdr,
1239                            sizeof(struct iscsi_hdr));
1240
1241         if (iscsi_buf_left(&r2t->sendbuf))
1242                 return;
1243
1244         iscsi_buf_init_sg(&r2t->sendbuf, r2t->sg);
1245         r2t->sg += 1;
1246 }
1247
1248 static void iscsi_set_padding(struct iscsi_tcp_cmd_task *tcp_ctask,
1249                               unsigned long len)
1250 {
1251         tcp_ctask->pad_count = len & (ISCSI_PAD_LEN - 1);
1252         if (!tcp_ctask->pad_count)
1253                 return;
1254
1255         tcp_ctask->pad_count = ISCSI_PAD_LEN - tcp_ctask->pad_count;
1256         debug_scsi("write padding %d bytes\n", tcp_ctask->pad_count);
1257         tcp_ctask->xmstate |= XMSTATE_W_PAD;
1258 }
1259
1260 /**
1261  * iscsi_tcp_cmd_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
1262  * @conn: iscsi connection
1263  * @ctask: scsi command task
1264  * @sc: scsi command
1265  **/
1266 static void
1267 iscsi_tcp_cmd_init(struct iscsi_cmd_task *ctask)
1268 {
1269         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1270
1271         BUG_ON(__kfifo_len(tcp_ctask->r2tqueue));
1272         tcp_ctask->xmstate = XMSTATE_CMD_HDR_INIT;
1273 }
1274
1275 /**
1276  * iscsi_tcp_mtask_xmit - xmit management(immediate) task
1277  * @conn: iscsi connection
1278  * @mtask: task management task
1279  *
1280  * Notes:
1281  *      The function can return -EAGAIN in which case caller must
1282  *      call it again later, or recover. '0' return code means successful
1283  *      xmit.
1284  *
1285  *      Management xmit state machine consists of these states:
1286  *              XMSTATE_IMM_HDR_INIT    - calculate digest of PDU Header
1287  *              XMSTATE_IMM_HDR         - PDU Header xmit in progress
1288  *              XMSTATE_IMM_DATA        - PDU Data xmit in progress
1289  *              XMSTATE_IDLE            - management PDU is done
1290  **/
1291 static int
1292 iscsi_tcp_mtask_xmit(struct iscsi_conn *conn, struct iscsi_mgmt_task *mtask)
1293 {
1294         struct iscsi_tcp_mgmt_task *tcp_mtask = mtask->dd_data;
1295         int rc;
1296
1297         debug_scsi("mtask deq [cid %d state %x itt 0x%x]\n",
1298                 conn->id, tcp_mtask->xmstate, mtask->itt);
1299
1300         if (tcp_mtask->xmstate & XMSTATE_IMM_HDR_INIT) {
1301                 iscsi_buf_init_iov(&tcp_mtask->headbuf, (char*)mtask->hdr,
1302                                    sizeof(struct iscsi_hdr));
1303
1304                 if (mtask->data_count) {
1305                         tcp_mtask->xmstate |= XMSTATE_IMM_DATA;
1306                         iscsi_buf_init_iov(&tcp_mtask->sendbuf,
1307                                            (char*)mtask->data,
1308                                            mtask->data_count);
1309                 }
1310
1311                 if (conn->c_stage != ISCSI_CONN_INITIAL_STAGE &&
1312                     conn->stop_stage != STOP_CONN_RECOVER &&
1313                     conn->hdrdgst_en)
1314                         iscsi_hdr_digest(conn, &tcp_mtask->headbuf,
1315                                         (u8*)tcp_mtask->hdrext);
1316
1317                 tcp_mtask->sent = 0;
1318                 tcp_mtask->xmstate &= ~XMSTATE_IMM_HDR_INIT;
1319                 tcp_mtask->xmstate |= XMSTATE_IMM_HDR;
1320         }
1321
1322         if (tcp_mtask->xmstate & XMSTATE_IMM_HDR) {
1323                 rc = iscsi_sendhdr(conn, &tcp_mtask->headbuf,
1324                                    mtask->data_count);
1325                 if (rc)
1326                         return rc;
1327                 tcp_mtask->xmstate &= ~XMSTATE_IMM_HDR;
1328         }
1329
1330         if (tcp_mtask->xmstate & XMSTATE_IMM_DATA) {
1331                 BUG_ON(!mtask->data_count);
1332                 tcp_mtask->xmstate &= ~XMSTATE_IMM_DATA;
1333                 /* FIXME: implement.
1334                  * Virtual buffer could be spreaded across multiple pages...
1335                  */
1336                 do {
1337                         int rc;
1338
1339                         rc = iscsi_sendpage(conn, &tcp_mtask->sendbuf,
1340                                         &mtask->data_count, &tcp_mtask->sent);
1341                         if (rc) {
1342                                 tcp_mtask->xmstate |= XMSTATE_IMM_DATA;
1343                                 return rc;
1344                         }
1345                 } while (mtask->data_count);
1346         }
1347
1348         BUG_ON(tcp_mtask->xmstate != XMSTATE_IDLE);
1349         if (mtask->hdr->itt == RESERVED_ITT) {
1350                 struct iscsi_session *session = conn->session;
1351
1352                 spin_lock_bh(&session->lock);
1353                 list_del(&conn->mtask->running);
1354                 __kfifo_put(session->mgmtpool.queue, (void*)&conn->mtask,
1355                             sizeof(void*));
1356                 spin_unlock_bh(&session->lock);
1357         }
1358         return 0;
1359 }
1360
1361 static int
1362 iscsi_send_cmd_hdr(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
1363 {
1364         struct scsi_cmnd *sc = ctask->sc;
1365         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1366         int rc = 0;
1367
1368         if (tcp_ctask->xmstate & XMSTATE_CMD_HDR_INIT) {
1369                 tcp_ctask->sent = 0;
1370                 tcp_ctask->sg_count = 0;
1371                 tcp_ctask->exp_datasn = 0;
1372
1373                 if (sc->sc_data_direction == DMA_TO_DEVICE) {
1374                         struct scatterlist *sg = scsi_sglist(sc);
1375
1376                         iscsi_buf_init_sg(&tcp_ctask->sendbuf, sg);
1377                         tcp_ctask->sg = sg + 1;
1378                         tcp_ctask->bad_sg = sg + scsi_sg_count(sc);
1379
1380                         debug_scsi("cmd [itt 0x%x total %d imm_data %d "
1381                                    "unsol count %d, unsol offset %d]\n",
1382                                    ctask->itt, scsi_bufflen(sc),
1383                                    ctask->imm_count, ctask->unsol_count,
1384                                    ctask->unsol_offset);
1385                 }
1386
1387                 iscsi_buf_init_iov(&tcp_ctask->headbuf, (char*)ctask->hdr,
1388                                   sizeof(struct iscsi_hdr));
1389
1390                 if (conn->hdrdgst_en)
1391                         iscsi_hdr_digest(conn, &tcp_ctask->headbuf,
1392                                          (u8*)tcp_ctask->hdrext);
1393                 tcp_ctask->xmstate &= ~XMSTATE_CMD_HDR_INIT;
1394                 tcp_ctask->xmstate |= XMSTATE_CMD_HDR_XMIT;
1395         }
1396
1397         if (tcp_ctask->xmstate & XMSTATE_CMD_HDR_XMIT) {
1398                 rc = iscsi_sendhdr(conn, &tcp_ctask->headbuf, ctask->imm_count);
1399                 if (rc)
1400                         return rc;
1401                 tcp_ctask->xmstate &= ~XMSTATE_CMD_HDR_XMIT;
1402
1403                 if (sc->sc_data_direction != DMA_TO_DEVICE)
1404                         return 0;
1405
1406                 if (ctask->imm_count) {
1407                         tcp_ctask->xmstate |= XMSTATE_IMM_DATA;
1408                         iscsi_set_padding(tcp_ctask, ctask->imm_count);
1409
1410                         if (ctask->conn->datadgst_en) {
1411                                 iscsi_data_digest_init(ctask->conn->dd_data,
1412                                                        tcp_ctask);
1413                                 tcp_ctask->immdigest = 0;
1414                         }
1415                 }
1416
1417                 if (ctask->unsol_count)
1418                         tcp_ctask->xmstate |=
1419                                         XMSTATE_UNS_HDR | XMSTATE_UNS_INIT;
1420         }
1421         return rc;
1422 }
1423
1424 static int
1425 iscsi_send_padding(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
1426 {
1427         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1428         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1429         int sent = 0, rc;
1430
1431         if (tcp_ctask->xmstate & XMSTATE_W_PAD) {
1432                 iscsi_buf_init_iov(&tcp_ctask->sendbuf, (char*)&tcp_ctask->pad,
1433                                    tcp_ctask->pad_count);
1434                 if (conn->datadgst_en)
1435                         crypto_hash_update(&tcp_conn->tx_hash,
1436                                            &tcp_ctask->sendbuf.sg,
1437                                            tcp_ctask->sendbuf.sg.length);
1438         } else if (!(tcp_ctask->xmstate & XMSTATE_W_RESEND_PAD))
1439                 return 0;
1440
1441         tcp_ctask->xmstate &= ~XMSTATE_W_PAD;
1442         tcp_ctask->xmstate &= ~XMSTATE_W_RESEND_PAD;
1443         debug_scsi("sending %d pad bytes for itt 0x%x\n",
1444                    tcp_ctask->pad_count, ctask->itt);
1445         rc = iscsi_sendpage(conn, &tcp_ctask->sendbuf, &tcp_ctask->pad_count,
1446                            &sent);
1447         if (rc) {
1448                 debug_scsi("padding send failed %d\n", rc);
1449                 tcp_ctask->xmstate |= XMSTATE_W_RESEND_PAD;
1450         }
1451         return rc;
1452 }
1453
1454 static int
1455 iscsi_send_digest(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
1456                         struct iscsi_buf *buf, uint32_t *digest)
1457 {
1458         struct iscsi_tcp_cmd_task *tcp_ctask;
1459         struct iscsi_tcp_conn *tcp_conn;
1460         int rc, sent = 0;
1461
1462         if (!conn->datadgst_en)
1463                 return 0;
1464
1465         tcp_ctask = ctask->dd_data;
1466         tcp_conn = conn->dd_data;
1467
1468         if (!(tcp_ctask->xmstate & XMSTATE_W_RESEND_DATA_DIGEST)) {
1469                 crypto_hash_final(&tcp_conn->tx_hash, (u8*)digest);
1470                 iscsi_buf_init_iov(buf, (char*)digest, 4);
1471         }
1472         tcp_ctask->xmstate &= ~XMSTATE_W_RESEND_DATA_DIGEST;
1473
1474         rc = iscsi_sendpage(conn, buf, &tcp_ctask->digest_count, &sent);
1475         if (!rc)
1476                 debug_scsi("sent digest 0x%x for itt 0x%x\n", *digest,
1477                           ctask->itt);
1478         else {
1479                 debug_scsi("sending digest 0x%x failed for itt 0x%x!\n",
1480                           *digest, ctask->itt);
1481                 tcp_ctask->xmstate |= XMSTATE_W_RESEND_DATA_DIGEST;
1482         }
1483         return rc;
1484 }
1485
1486 static int
1487 iscsi_send_data(struct iscsi_cmd_task *ctask, struct iscsi_buf *sendbuf,
1488                 struct scatterlist **sg, int *sent, int *count,
1489                 struct iscsi_buf *digestbuf, uint32_t *digest)
1490 {
1491         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1492         struct iscsi_conn *conn = ctask->conn;
1493         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1494         int rc, buf_sent, offset;
1495
1496         while (*count) {
1497                 buf_sent = 0;
1498                 offset = sendbuf->sent;
1499
1500                 rc = iscsi_sendpage(conn, sendbuf, count, &buf_sent);
1501                 *sent = *sent + buf_sent;
1502                 if (buf_sent && conn->datadgst_en)
1503                         partial_sg_digest_update(&tcp_conn->tx_hash,
1504                                 &sendbuf->sg, sendbuf->sg.offset + offset,
1505                                 buf_sent);
1506                 if (!iscsi_buf_left(sendbuf) && *sg != tcp_ctask->bad_sg) {
1507                         iscsi_buf_init_sg(sendbuf, *sg);
1508                         *sg = *sg + 1;
1509                 }
1510
1511                 if (rc)
1512                         return rc;
1513         }
1514
1515         rc = iscsi_send_padding(conn, ctask);
1516         if (rc)
1517                 return rc;
1518
1519         return iscsi_send_digest(conn, ctask, digestbuf, digest);
1520 }
1521
1522 static int
1523 iscsi_send_unsol_hdr(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
1524 {
1525         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1526         struct iscsi_data_task *dtask;
1527         int rc;
1528
1529         tcp_ctask->xmstate |= XMSTATE_UNS_DATA;
1530         if (tcp_ctask->xmstate & XMSTATE_UNS_INIT) {
1531                 dtask = &tcp_ctask->unsol_dtask;
1532
1533                 iscsi_prep_unsolicit_data_pdu(ctask, &dtask->hdr);
1534                 iscsi_buf_init_iov(&tcp_ctask->headbuf, (char*)&dtask->hdr,
1535                                    sizeof(struct iscsi_hdr));
1536                 if (conn->hdrdgst_en)
1537                         iscsi_hdr_digest(conn, &tcp_ctask->headbuf,
1538                                         (u8*)dtask->hdrext);
1539
1540                 tcp_ctask->xmstate &= ~XMSTATE_UNS_INIT;
1541                 iscsi_set_padding(tcp_ctask, ctask->data_count);
1542         }
1543
1544         rc = iscsi_sendhdr(conn, &tcp_ctask->headbuf, ctask->data_count);
1545         if (rc) {
1546                 tcp_ctask->xmstate &= ~XMSTATE_UNS_DATA;
1547                 tcp_ctask->xmstate |= XMSTATE_UNS_HDR;
1548                 return rc;
1549         }
1550
1551         if (conn->datadgst_en) {
1552                 dtask = &tcp_ctask->unsol_dtask;
1553                 iscsi_data_digest_init(ctask->conn->dd_data, tcp_ctask);
1554                 dtask->digest = 0;
1555         }
1556
1557         debug_scsi("uns dout [itt 0x%x dlen %d sent %d]\n",
1558                    ctask->itt, ctask->unsol_count, tcp_ctask->sent);
1559         return 0;
1560 }
1561
1562 static int
1563 iscsi_send_unsol_pdu(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
1564 {
1565         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1566         int rc;
1567
1568         if (tcp_ctask->xmstate & XMSTATE_UNS_HDR) {
1569                 BUG_ON(!ctask->unsol_count);
1570                 tcp_ctask->xmstate &= ~XMSTATE_UNS_HDR;
1571 send_hdr:
1572                 rc = iscsi_send_unsol_hdr(conn, ctask);
1573                 if (rc)
1574                         return rc;
1575         }
1576
1577         if (tcp_ctask->xmstate & XMSTATE_UNS_DATA) {
1578                 struct iscsi_data_task *dtask = &tcp_ctask->unsol_dtask;
1579                 int start = tcp_ctask->sent;
1580
1581                 rc = iscsi_send_data(ctask, &tcp_ctask->sendbuf, &tcp_ctask->sg,
1582                                      &tcp_ctask->sent, &ctask->data_count,
1583                                      &dtask->digestbuf, &dtask->digest);
1584                 ctask->unsol_count -= tcp_ctask->sent - start;
1585                 if (rc)
1586                         return rc;
1587                 tcp_ctask->xmstate &= ~XMSTATE_UNS_DATA;
1588                 /*
1589                  * Done with the Data-Out. Next, check if we need
1590                  * to send another unsolicited Data-Out.
1591                  */
1592                 if (ctask->unsol_count) {
1593                         debug_scsi("sending more uns\n");
1594                         tcp_ctask->xmstate |= XMSTATE_UNS_INIT;
1595                         goto send_hdr;
1596                 }
1597         }
1598         return 0;
1599 }
1600
1601 static int iscsi_send_sol_pdu(struct iscsi_conn *conn,
1602                               struct iscsi_cmd_task *ctask)
1603 {
1604         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1605         struct iscsi_session *session = conn->session;
1606         struct iscsi_r2t_info *r2t;
1607         struct iscsi_data_task *dtask;
1608         int left, rc;
1609
1610         if (tcp_ctask->xmstate & XMSTATE_SOL_HDR_INIT) {
1611                 if (!tcp_ctask->r2t) {
1612                         spin_lock_bh(&session->lock);
1613                         __kfifo_get(tcp_ctask->r2tqueue, (void*)&tcp_ctask->r2t,
1614                                     sizeof(void*));
1615                         spin_unlock_bh(&session->lock);
1616                 }
1617 send_hdr:
1618                 r2t = tcp_ctask->r2t;
1619                 dtask = &r2t->dtask;
1620
1621                 if (conn->hdrdgst_en)
1622                         iscsi_hdr_digest(conn, &r2t->headbuf,
1623                                         (u8*)dtask->hdrext);
1624                 tcp_ctask->xmstate &= ~XMSTATE_SOL_HDR_INIT;
1625                 tcp_ctask->xmstate |= XMSTATE_SOL_HDR;
1626         }
1627
1628         if (tcp_ctask->xmstate & XMSTATE_SOL_HDR) {
1629                 r2t = tcp_ctask->r2t;
1630                 dtask = &r2t->dtask;
1631
1632                 rc = iscsi_sendhdr(conn, &r2t->headbuf, r2t->data_count);
1633                 if (rc)
1634                         return rc;
1635                 tcp_ctask->xmstate &= ~XMSTATE_SOL_HDR;
1636                 tcp_ctask->xmstate |= XMSTATE_SOL_DATA;
1637
1638                 if (conn->datadgst_en) {
1639                         iscsi_data_digest_init(conn->dd_data, tcp_ctask);
1640                         dtask->digest = 0;
1641                 }
1642
1643                 iscsi_set_padding(tcp_ctask, r2t->data_count);
1644                 debug_scsi("sol dout [dsn %d itt 0x%x dlen %d sent %d]\n",
1645                         r2t->solicit_datasn - 1, ctask->itt, r2t->data_count,
1646                         r2t->sent);
1647         }
1648
1649         if (tcp_ctask->xmstate & XMSTATE_SOL_DATA) {
1650                 r2t = tcp_ctask->r2t;
1651                 dtask = &r2t->dtask;
1652
1653                 rc = iscsi_send_data(ctask, &r2t->sendbuf, &r2t->sg,
1654                                      &r2t->sent, &r2t->data_count,
1655                                      &dtask->digestbuf, &dtask->digest);
1656                 if (rc)
1657                         return rc;
1658                 tcp_ctask->xmstate &= ~XMSTATE_SOL_DATA;
1659
1660                 /*
1661                  * Done with this Data-Out. Next, check if we have
1662                  * to send another Data-Out for this R2T.
1663                  */
1664                 BUG_ON(r2t->data_length - r2t->sent < 0);
1665                 left = r2t->data_length - r2t->sent;
1666                 if (left) {
1667                         iscsi_solicit_data_cont(conn, ctask, r2t, left);
1668                         goto send_hdr;
1669                 }
1670
1671                 /*
1672                  * Done with this R2T. Check if there are more
1673                  * outstanding R2Ts ready to be processed.
1674                  */
1675                 spin_lock_bh(&session->lock);
1676                 tcp_ctask->r2t = NULL;
1677                 __kfifo_put(tcp_ctask->r2tpool.queue, (void*)&r2t,
1678                             sizeof(void*));
1679                 if (__kfifo_get(tcp_ctask->r2tqueue, (void*)&r2t,
1680                                 sizeof(void*))) {
1681                         tcp_ctask->r2t = r2t;
1682                         spin_unlock_bh(&session->lock);
1683                         goto send_hdr;
1684                 }
1685                 spin_unlock_bh(&session->lock);
1686         }
1687         return 0;
1688 }
1689
1690 /**
1691  * iscsi_tcp_ctask_xmit - xmit normal PDU task
1692  * @conn: iscsi connection
1693  * @ctask: iscsi command task
1694  *
1695  * Notes:
1696  *      The function can return -EAGAIN in which case caller must
1697  *      call it again later, or recover. '0' return code means successful
1698  *      xmit.
1699  *      The function is devided to logical helpers (above) for the different
1700  *      xmit stages.
1701  *
1702  *iscsi_send_cmd_hdr()
1703  *      XMSTATE_CMD_HDR_INIT - prepare Header and Data buffers Calculate
1704  *                             Header Digest
1705  *      XMSTATE_CMD_HDR_XMIT - Transmit header in progress
1706  *
1707  *iscsi_send_padding
1708  *      XMSTATE_W_PAD        - Prepare and send pading
1709  *      XMSTATE_W_RESEND_PAD - retry send pading
1710  *
1711  *iscsi_send_digest
1712  *      XMSTATE_W_RESEND_DATA_DIGEST - Finalize and send Data Digest
1713  *      XMSTATE_W_RESEND_DATA_DIGEST - retry sending digest
1714  *
1715  *iscsi_send_unsol_hdr
1716  *      XMSTATE_UNS_INIT     - prepare un-solicit data header and digest
1717  *      XMSTATE_UNS_HDR      - send un-solicit header
1718  *
1719  *iscsi_send_unsol_pdu
1720  *      XMSTATE_UNS_DATA     - send un-solicit data in progress
1721  *
1722  *iscsi_send_sol_pdu
1723  *      XMSTATE_SOL_HDR_INIT - solicit data header and digest initialize
1724  *      XMSTATE_SOL_HDR      - send solicit header
1725  *      XMSTATE_SOL_DATA     - send solicit data
1726  *
1727  *iscsi_tcp_ctask_xmit
1728  *      XMSTATE_IMM_DATA     - xmit managment data (??)
1729  **/
1730 static int
1731 iscsi_tcp_ctask_xmit(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
1732 {
1733         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1734         int rc = 0;
1735
1736         debug_scsi("ctask deq [cid %d xmstate %x itt 0x%x]\n",
1737                 conn->id, tcp_ctask->xmstate, ctask->itt);
1738
1739         rc = iscsi_send_cmd_hdr(conn, ctask);
1740         if (rc)
1741                 return rc;
1742         if (ctask->sc->sc_data_direction != DMA_TO_DEVICE)
1743                 return 0;
1744
1745         if (tcp_ctask->xmstate & XMSTATE_IMM_DATA) {
1746                 rc = iscsi_send_data(ctask, &tcp_ctask->sendbuf, &tcp_ctask->sg,
1747                                      &tcp_ctask->sent, &ctask->imm_count,
1748                                      &tcp_ctask->immbuf, &tcp_ctask->immdigest);
1749                 if (rc)
1750                         return rc;
1751                 tcp_ctask->xmstate &= ~XMSTATE_IMM_DATA;
1752         }
1753
1754         rc = iscsi_send_unsol_pdu(conn, ctask);
1755         if (rc)
1756                 return rc;
1757
1758         rc = iscsi_send_sol_pdu(conn, ctask);
1759         if (rc)
1760                 return rc;
1761
1762         return rc;
1763 }
1764
1765 static struct iscsi_cls_conn *
1766 iscsi_tcp_conn_create(struct iscsi_cls_session *cls_session, uint32_t conn_idx)
1767 {
1768         struct iscsi_conn *conn;
1769         struct iscsi_cls_conn *cls_conn;
1770         struct iscsi_tcp_conn *tcp_conn;
1771
1772         cls_conn = iscsi_conn_setup(cls_session, conn_idx);
1773         if (!cls_conn)
1774                 return NULL;
1775         conn = cls_conn->dd_data;
1776         /*
1777          * due to strange issues with iser these are not set
1778          * in iscsi_conn_setup
1779          */
1780         conn->max_recv_dlength = ISCSI_DEF_MAX_RECV_SEG_LEN;
1781
1782         tcp_conn = kzalloc(sizeof(*tcp_conn), GFP_KERNEL);
1783         if (!tcp_conn)
1784                 goto tcp_conn_alloc_fail;
1785
1786         conn->dd_data = tcp_conn;
1787         tcp_conn->iscsi_conn = conn;
1788         tcp_conn->in_progress = IN_PROGRESS_WAIT_HEADER;
1789         /* initial operational parameters */
1790         tcp_conn->hdr_size = sizeof(struct iscsi_hdr);
1791
1792         tcp_conn->tx_hash.tfm = crypto_alloc_hash("crc32c", 0,
1793                                                   CRYPTO_ALG_ASYNC);
1794         tcp_conn->tx_hash.flags = 0;
1795         if (IS_ERR(tcp_conn->tx_hash.tfm)) {
1796                 printk(KERN_ERR "Could not create connection due to crc32c "
1797                        "loading error %ld. Make sure the crc32c module is "
1798                        "built as a module or into the kernel\n",
1799                         PTR_ERR(tcp_conn->tx_hash.tfm));
1800                 goto free_tcp_conn;
1801         }
1802
1803         tcp_conn->rx_hash.tfm = crypto_alloc_hash("crc32c", 0,
1804                                                   CRYPTO_ALG_ASYNC);
1805         tcp_conn->rx_hash.flags = 0;
1806         if (IS_ERR(tcp_conn->rx_hash.tfm)) {
1807                 printk(KERN_ERR "Could not create connection due to crc32c "
1808                        "loading error %ld. Make sure the crc32c module is "
1809                        "built as a module or into the kernel\n",
1810                         PTR_ERR(tcp_conn->rx_hash.tfm));
1811                 goto free_tx_tfm;
1812         }
1813
1814         return cls_conn;
1815
1816 free_tx_tfm:
1817         crypto_free_hash(tcp_conn->tx_hash.tfm);
1818 free_tcp_conn:
1819         kfree(tcp_conn);
1820 tcp_conn_alloc_fail:
1821         iscsi_conn_teardown(cls_conn);
1822         return NULL;
1823 }
1824
1825 static void
1826 iscsi_tcp_release_conn(struct iscsi_conn *conn)
1827 {
1828         struct iscsi_session *session = conn->session;
1829         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1830         struct socket *sock = tcp_conn->sock;
1831
1832         if (!sock)
1833                 return;
1834
1835         sock_hold(sock->sk);
1836         iscsi_conn_restore_callbacks(tcp_conn);
1837         sock_put(sock->sk);
1838
1839         spin_lock_bh(&session->lock);
1840         tcp_conn->sock = NULL;
1841         conn->recv_lock = NULL;
1842         spin_unlock_bh(&session->lock);
1843         sockfd_put(sock);
1844 }
1845
1846 static void
1847 iscsi_tcp_conn_destroy(struct iscsi_cls_conn *cls_conn)
1848 {
1849         struct iscsi_conn *conn = cls_conn->dd_data;
1850         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1851
1852         iscsi_tcp_release_conn(conn);
1853         iscsi_conn_teardown(cls_conn);
1854
1855         if (tcp_conn->tx_hash.tfm)
1856                 crypto_free_hash(tcp_conn->tx_hash.tfm);
1857         if (tcp_conn->rx_hash.tfm)
1858                 crypto_free_hash(tcp_conn->rx_hash.tfm);
1859
1860         kfree(tcp_conn);
1861 }
1862
1863 static void
1864 iscsi_tcp_conn_stop(struct iscsi_cls_conn *cls_conn, int flag)
1865 {
1866         struct iscsi_conn *conn = cls_conn->dd_data;
1867         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1868
1869         iscsi_conn_stop(cls_conn, flag);
1870         iscsi_tcp_release_conn(conn);
1871         tcp_conn->hdr_size = sizeof(struct iscsi_hdr);
1872 }
1873
1874 static int iscsi_tcp_get_addr(struct iscsi_conn *conn, struct socket *sock,
1875                               char *buf, int *port,
1876                               int (*getname)(struct socket *, struct sockaddr *,
1877                                         int *addrlen))
1878 {
1879         struct sockaddr_storage *addr;
1880         struct sockaddr_in6 *sin6;
1881         struct sockaddr_in *sin;
1882         int rc = 0, len;
1883
1884         addr = kmalloc(sizeof(*addr), GFP_KERNEL);
1885         if (!addr)
1886                 return -ENOMEM;
1887
1888         if (getname(sock, (struct sockaddr *) addr, &len)) {
1889                 rc = -ENODEV;
1890                 goto free_addr;
1891         }
1892
1893         switch (addr->ss_family) {
1894         case AF_INET:
1895                 sin = (struct sockaddr_in *)addr;
1896                 spin_lock_bh(&conn->session->lock);
1897                 sprintf(buf, NIPQUAD_FMT, NIPQUAD(sin->sin_addr.s_addr));
1898                 *port = be16_to_cpu(sin->sin_port);
1899                 spin_unlock_bh(&conn->session->lock);
1900                 break;
1901         case AF_INET6:
1902                 sin6 = (struct sockaddr_in6 *)addr;
1903                 spin_lock_bh(&conn->session->lock);
1904                 sprintf(buf, NIP6_FMT, NIP6(sin6->sin6_addr));
1905                 *port = be16_to_cpu(sin6->sin6_port);
1906                 spin_unlock_bh(&conn->session->lock);
1907                 break;
1908         }
1909 free_addr:
1910         kfree(addr);
1911         return rc;
1912 }
1913
1914 static int
1915 iscsi_tcp_conn_bind(struct iscsi_cls_session *cls_session,
1916                     struct iscsi_cls_conn *cls_conn, uint64_t transport_eph,
1917                     int is_leading)
1918 {
1919         struct iscsi_conn *conn = cls_conn->dd_data;
1920         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1921         struct sock *sk;
1922         struct socket *sock;
1923         int err;
1924
1925         /* lookup for existing socket */
1926         sock = sockfd_lookup((int)transport_eph, &err);
1927         if (!sock) {
1928                 printk(KERN_ERR "iscsi_tcp: sockfd_lookup failed %d\n", err);
1929                 return -EEXIST;
1930         }
1931         /*
1932          * copy these values now because if we drop the session
1933          * userspace may still want to query the values since we will
1934          * be using them for the reconnect
1935          */
1936         err = iscsi_tcp_get_addr(conn, sock, conn->portal_address,
1937                                  &conn->portal_port, kernel_getpeername);
1938         if (err)
1939                 goto free_socket;
1940
1941         err = iscsi_tcp_get_addr(conn, sock, conn->local_address,
1942                                 &conn->local_port, kernel_getsockname);
1943         if (err)
1944                 goto free_socket;
1945
1946         err = iscsi_conn_bind(cls_session, cls_conn, is_leading);
1947         if (err)
1948                 goto free_socket;
1949
1950         /* bind iSCSI connection and socket */
1951         tcp_conn->sock = sock;
1952
1953         /* setup Socket parameters */
1954         sk = sock->sk;
1955         sk->sk_reuse = 1;
1956         sk->sk_sndtimeo = 15 * HZ; /* FIXME: make it configurable */
1957         sk->sk_allocation = GFP_ATOMIC;
1958
1959         /* FIXME: disable Nagle's algorithm */
1960
1961         /*
1962          * Intercept TCP callbacks for sendfile like receive
1963          * processing.
1964          */
1965         conn->recv_lock = &sk->sk_callback_lock;
1966         iscsi_conn_set_callbacks(conn);
1967         tcp_conn->sendpage = tcp_conn->sock->ops->sendpage;
1968         /*
1969          * set receive state machine into initial state
1970          */
1971         tcp_conn->in_progress = IN_PROGRESS_WAIT_HEADER;
1972         return 0;
1973
1974 free_socket:
1975         sockfd_put(sock);
1976         return err;
1977 }
1978
1979 /* called with host lock */
1980 static void
1981 iscsi_tcp_mgmt_init(struct iscsi_conn *conn, struct iscsi_mgmt_task *mtask)
1982 {
1983         struct iscsi_tcp_mgmt_task *tcp_mtask = mtask->dd_data;
1984         tcp_mtask->xmstate = XMSTATE_IMM_HDR_INIT;
1985 }
1986
1987 static int
1988 iscsi_r2tpool_alloc(struct iscsi_session *session)
1989 {
1990         int i;
1991         int cmd_i;
1992
1993         /*
1994          * initialize per-task: R2T pool and xmit queue
1995          */
1996         for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
1997                 struct iscsi_cmd_task *ctask = session->cmds[cmd_i];
1998                 struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1999
2000                 /*
2001                  * pre-allocated x4 as much r2ts to handle race when
2002                  * target acks DataOut faster than we data_xmit() queues
2003                  * could replenish r2tqueue.
2004                  */
2005
2006                 /* R2T pool */
2007                 if (iscsi_pool_init(&tcp_ctask->r2tpool, session->max_r2t * 4,
2008                                     (void***)&tcp_ctask->r2ts,
2009                                     sizeof(struct iscsi_r2t_info))) {
2010                         goto r2t_alloc_fail;
2011                 }
2012
2013                 /* R2T xmit queue */
2014                 tcp_ctask->r2tqueue = kfifo_alloc(
2015                       session->max_r2t * 4 * sizeof(void*), GFP_KERNEL, NULL);
2016                 if (tcp_ctask->r2tqueue == ERR_PTR(-ENOMEM)) {
2017                         iscsi_pool_free(&tcp_ctask->r2tpool,
2018                                         (void**)tcp_ctask->r2ts);
2019                         goto r2t_alloc_fail;
2020                 }
2021         }
2022
2023         return 0;
2024
2025 r2t_alloc_fail:
2026         for (i = 0; i < cmd_i; i++) {
2027                 struct iscsi_cmd_task *ctask = session->cmds[i];
2028                 struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
2029
2030                 kfifo_free(tcp_ctask->r2tqueue);
2031                 iscsi_pool_free(&tcp_ctask->r2tpool,
2032                                 (void**)tcp_ctask->r2ts);
2033         }
2034         return -ENOMEM;
2035 }
2036
2037 static void
2038 iscsi_r2tpool_free(struct iscsi_session *session)
2039 {
2040         int i;
2041
2042         for (i = 0; i < session->cmds_max; i++) {
2043                 struct iscsi_cmd_task *ctask = session->cmds[i];
2044                 struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
2045
2046                 kfifo_free(tcp_ctask->r2tqueue);
2047                 iscsi_pool_free(&tcp_ctask->r2tpool,
2048                                 (void**)tcp_ctask->r2ts);
2049         }
2050 }
2051
2052 static int
2053 iscsi_conn_set_param(struct iscsi_cls_conn *cls_conn, enum iscsi_param param,
2054                      char *buf, int buflen)
2055 {
2056         struct iscsi_conn *conn = cls_conn->dd_data;
2057         struct iscsi_session *session = conn->session;
2058         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
2059         int value;
2060
2061         switch(param) {
2062         case ISCSI_PARAM_HDRDGST_EN:
2063                 iscsi_set_param(cls_conn, param, buf, buflen);
2064                 tcp_conn->hdr_size = sizeof(struct iscsi_hdr);
2065                 if (conn->hdrdgst_en)
2066                         tcp_conn->hdr_size += sizeof(__u32);
2067                 break;
2068         case ISCSI_PARAM_DATADGST_EN:
2069                 iscsi_set_param(cls_conn, param, buf, buflen);
2070                 tcp_conn->sendpage = conn->datadgst_en ?
2071                         sock_no_sendpage : tcp_conn->sock->ops->sendpage;
2072                 break;
2073         case ISCSI_PARAM_MAX_R2T:
2074                 sscanf(buf, "%d", &value);
2075                 if (session->max_r2t == roundup_pow_of_two(value))
2076                         break;
2077                 iscsi_r2tpool_free(session);
2078                 iscsi_set_param(cls_conn, param, buf, buflen);
2079                 if (session->max_r2t & (session->max_r2t - 1))
2080                         session->max_r2t = roundup_pow_of_two(session->max_r2t);
2081                 if (iscsi_r2tpool_alloc(session))
2082                         return -ENOMEM;
2083                 break;
2084         default:
2085                 return iscsi_set_param(cls_conn, param, buf, buflen);
2086         }
2087
2088         return 0;
2089 }
2090
2091 static int
2092 iscsi_tcp_conn_get_param(struct iscsi_cls_conn *cls_conn,
2093                          enum iscsi_param param, char *buf)
2094 {
2095         struct iscsi_conn *conn = cls_conn->dd_data;
2096         int len;
2097
2098         switch(param) {
2099         case ISCSI_PARAM_CONN_PORT:
2100                 spin_lock_bh(&conn->session->lock);
2101                 len = sprintf(buf, "%hu\n", conn->portal_port);
2102                 spin_unlock_bh(&conn->session->lock);
2103                 break;
2104         case ISCSI_PARAM_CONN_ADDRESS:
2105                 spin_lock_bh(&conn->session->lock);
2106                 len = sprintf(buf, "%s\n", conn->portal_address);
2107                 spin_unlock_bh(&conn->session->lock);
2108                 break;
2109         default:
2110                 return iscsi_conn_get_param(cls_conn, param, buf);
2111         }
2112
2113         return len;
2114 }
2115
2116 static int
2117 iscsi_tcp_host_get_param(struct Scsi_Host *shost, enum iscsi_host_param param,
2118                          char *buf)
2119 {
2120         struct iscsi_session *session = iscsi_hostdata(shost->hostdata);
2121         int len;
2122
2123         switch (param) {
2124         case ISCSI_HOST_PARAM_IPADDRESS:
2125                 spin_lock_bh(&session->lock);
2126                 if (!session->leadconn)
2127                         len = -ENODEV;
2128                 else
2129                         len = sprintf(buf, "%s\n",
2130                                      session->leadconn->local_address);
2131                 spin_unlock_bh(&session->lock);
2132                 break;
2133         default:
2134                 return iscsi_host_get_param(shost, param, buf);
2135         }
2136         return len;
2137 }
2138
2139 static void
2140 iscsi_conn_get_stats(struct iscsi_cls_conn *cls_conn, struct iscsi_stats *stats)
2141 {
2142         struct iscsi_conn *conn = cls_conn->dd_data;
2143         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
2144
2145         stats->txdata_octets = conn->txdata_octets;
2146         stats->rxdata_octets = conn->rxdata_octets;
2147         stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
2148         stats->dataout_pdus = conn->dataout_pdus_cnt;
2149         stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
2150         stats->datain_pdus = conn->datain_pdus_cnt;
2151         stats->r2t_pdus = conn->r2t_pdus_cnt;
2152         stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
2153         stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
2154         stats->custom_length = 3;
2155         strcpy(stats->custom[0].desc, "tx_sendpage_failures");
2156         stats->custom[0].value = tcp_conn->sendpage_failures_cnt;
2157         strcpy(stats->custom[1].desc, "rx_discontiguous_hdr");
2158         stats->custom[1].value = tcp_conn->discontiguous_hdr_cnt;
2159         strcpy(stats->custom[2].desc, "eh_abort_cnt");
2160         stats->custom[2].value = conn->eh_abort_cnt;
2161 }
2162
2163 static struct iscsi_cls_session *
2164 iscsi_tcp_session_create(struct iscsi_transport *iscsit,
2165                          struct scsi_transport_template *scsit,
2166                          uint16_t cmds_max, uint16_t qdepth,
2167                          uint32_t initial_cmdsn, uint32_t *hostno)
2168 {
2169         struct iscsi_cls_session *cls_session;
2170         struct iscsi_session *session;
2171         uint32_t hn;
2172         int cmd_i;
2173
2174         cls_session = iscsi_session_setup(iscsit, scsit, cmds_max, qdepth,
2175                                          sizeof(struct iscsi_tcp_cmd_task),
2176                                          sizeof(struct iscsi_tcp_mgmt_task),
2177                                          initial_cmdsn, &hn);
2178         if (!cls_session)
2179                 return NULL;
2180         *hostno = hn;
2181
2182         session = class_to_transport_session(cls_session);
2183         for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
2184                 struct iscsi_cmd_task *ctask = session->cmds[cmd_i];
2185                 struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
2186
2187                 ctask->hdr = &tcp_ctask->hdr;
2188         }
2189
2190         for (cmd_i = 0; cmd_i < session->mgmtpool_max; cmd_i++) {
2191                 struct iscsi_mgmt_task *mtask = session->mgmt_cmds[cmd_i];
2192                 struct iscsi_tcp_mgmt_task *tcp_mtask = mtask->dd_data;
2193
2194                 mtask->hdr = &tcp_mtask->hdr;
2195         }
2196
2197         if (iscsi_r2tpool_alloc(class_to_transport_session(cls_session)))
2198                 goto r2tpool_alloc_fail;
2199
2200         return cls_session;
2201
2202 r2tpool_alloc_fail:
2203         iscsi_session_teardown(cls_session);
2204         return NULL;
2205 }
2206
2207 static void iscsi_tcp_session_destroy(struct iscsi_cls_session *cls_session)
2208 {
2209         iscsi_r2tpool_free(class_to_transport_session(cls_session));
2210         iscsi_session_teardown(cls_session);
2211 }
2212
2213 static int iscsi_tcp_slave_configure(struct scsi_device *sdev)
2214 {
2215         blk_queue_bounce_limit(sdev->request_queue, BLK_BOUNCE_ANY);
2216         blk_queue_dma_alignment(sdev->request_queue, 0);
2217         return 0;
2218 }
2219
2220 static struct scsi_host_template iscsi_sht = {
2221         .module                 = THIS_MODULE,
2222         .name                   = "iSCSI Initiator over TCP/IP",
2223         .queuecommand           = iscsi_queuecommand,
2224         .change_queue_depth     = iscsi_change_queue_depth,
2225         .can_queue              = ISCSI_DEF_XMIT_CMDS_MAX - 1,
2226         .sg_tablesize           = ISCSI_SG_TABLESIZE,
2227         .max_sectors            = 0xFFFF,
2228         .cmd_per_lun            = ISCSI_DEF_CMD_PER_LUN,
2229         .eh_abort_handler       = iscsi_eh_abort,
2230         .eh_host_reset_handler  = iscsi_eh_host_reset,
2231         .use_clustering         = DISABLE_CLUSTERING,
2232         .slave_configure        = iscsi_tcp_slave_configure,
2233         .proc_name              = "iscsi_tcp",
2234         .this_id                = -1,
2235 };
2236
2237 static struct iscsi_transport iscsi_tcp_transport = {
2238         .owner                  = THIS_MODULE,
2239         .name                   = "tcp",
2240         .caps                   = CAP_RECOVERY_L0 | CAP_MULTI_R2T | CAP_HDRDGST
2241                                   | CAP_DATADGST,
2242         .param_mask             = ISCSI_MAX_RECV_DLENGTH |
2243                                   ISCSI_MAX_XMIT_DLENGTH |
2244                                   ISCSI_HDRDGST_EN |
2245                                   ISCSI_DATADGST_EN |
2246                                   ISCSI_INITIAL_R2T_EN |
2247                                   ISCSI_MAX_R2T |
2248                                   ISCSI_IMM_DATA_EN |
2249                                   ISCSI_FIRST_BURST |
2250                                   ISCSI_MAX_BURST |
2251                                   ISCSI_PDU_INORDER_EN |
2252                                   ISCSI_DATASEQ_INORDER_EN |
2253                                   ISCSI_ERL |
2254                                   ISCSI_CONN_PORT |
2255                                   ISCSI_CONN_ADDRESS |
2256                                   ISCSI_EXP_STATSN |
2257                                   ISCSI_PERSISTENT_PORT |
2258                                   ISCSI_PERSISTENT_ADDRESS |
2259                                   ISCSI_TARGET_NAME | ISCSI_TPGT |
2260                                   ISCSI_USERNAME | ISCSI_PASSWORD |
2261                                   ISCSI_USERNAME_IN | ISCSI_PASSWORD_IN,
2262         .host_param_mask        = ISCSI_HOST_HWADDRESS | ISCSI_HOST_IPADDRESS |
2263                                   ISCSI_HOST_INITIATOR_NAME |
2264                                   ISCSI_HOST_NETDEV_NAME,
2265         .host_template          = &iscsi_sht,
2266         .conndata_size          = sizeof(struct iscsi_conn),
2267         .max_conn               = 1,
2268         .max_cmd_len            = ISCSI_TCP_MAX_CMD_LEN,
2269         /* session management */
2270         .create_session         = iscsi_tcp_session_create,
2271         .destroy_session        = iscsi_tcp_session_destroy,
2272         /* connection management */
2273         .create_conn            = iscsi_tcp_conn_create,
2274         .bind_conn              = iscsi_tcp_conn_bind,
2275         .destroy_conn           = iscsi_tcp_conn_destroy,
2276         .set_param              = iscsi_conn_set_param,
2277         .get_conn_param         = iscsi_tcp_conn_get_param,
2278         .get_session_param      = iscsi_session_get_param,
2279         .start_conn             = iscsi_conn_start,
2280         .stop_conn              = iscsi_tcp_conn_stop,
2281         /* iscsi host params */
2282         .get_host_param         = iscsi_tcp_host_get_param,
2283         .set_host_param         = iscsi_host_set_param,
2284         /* IO */
2285         .send_pdu               = iscsi_conn_send_pdu,
2286         .get_stats              = iscsi_conn_get_stats,
2287         .init_cmd_task          = iscsi_tcp_cmd_init,
2288         .init_mgmt_task         = iscsi_tcp_mgmt_init,
2289         .xmit_cmd_task          = iscsi_tcp_ctask_xmit,
2290         .xmit_mgmt_task         = iscsi_tcp_mtask_xmit,
2291         .cleanup_cmd_task       = iscsi_tcp_cleanup_ctask,
2292         /* recovery */
2293         .session_recovery_timedout = iscsi_session_recovery_timedout,
2294 };
2295
2296 static int __init
2297 iscsi_tcp_init(void)
2298 {
2299         if (iscsi_max_lun < 1) {
2300                 printk(KERN_ERR "iscsi_tcp: Invalid max_lun value of %u\n",
2301                        iscsi_max_lun);
2302                 return -EINVAL;
2303         }
2304         iscsi_tcp_transport.max_lun = iscsi_max_lun;
2305
2306         if (!iscsi_register_transport(&iscsi_tcp_transport))
2307                 return -ENODEV;
2308
2309         return 0;
2310 }
2311
2312 static void __exit
2313 iscsi_tcp_exit(void)
2314 {
2315         iscsi_unregister_transport(&iscsi_tcp_transport);
2316 }
2317
2318 module_init(iscsi_tcp_init);
2319 module_exit(iscsi_tcp_exit);