drivers/scsi/libiscsi_tcp.c

   1 /*
   2  * iSCSI over TCP/IP Data-Path lib
   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/slab.h>
  33 #include <linux/file.h>
  34 #include <linux/blkdev.h>
  35 #include <linux/crypto.h>
  36 #include <linux/delay.h>
  37 #include <linux/kfifo.h>
  38 #include <linux/scatterlist.h>
  39 #include <linux/module.h>
  40 #include <net/tcp.h>
  41 #include <scsi/scsi_cmnd.h>
  42 #include <scsi/scsi_device.h>
  43 #include <scsi/scsi_host.h>
  44 #include <scsi/scsi.h>
  45 #include <scsi/scsi_transport_iscsi.h>
  46
  47 #include "iscsi_tcp.h"
  48
  49 MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, "
  50               "Dmitry Yusupov <dmitry_yus@yahoo.com>, "
  51               "Alex Aizman <itn780@yahoo.com>");
  52 MODULE_DESCRIPTION("iSCSI/TCP data-path");
  53 MODULE_LICENSE("GPL");
  54
  55 static int iscsi_dbg_libtcp;
  56 module_param_named(debug_libiscsi_tcp, iscsi_dbg_libtcp, int,
  57                    S_IRUGO | S_IWUSR);
  58 MODULE_PARM_DESC(debug_libiscsi_tcp, "Turn on debugging for libiscsi_tcp "
  59                  "module. Set to 1 to turn on, and zero to turn off. Default "
  60                  "is off.");
  61
  62 #define ISCSI_DBG_TCP(_conn, dbg_fmt, arg...)                   \
  63         do {                                                    \
  64                 if (iscsi_dbg_libtcp)                           \
  65                         iscsi_conn_printk(KERN_INFO, _conn,     \
  66                                              "%s " dbg_fmt,     \
  67                                              __func__, ##arg);  \
  68         } while (0);
  69
  70 static int iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
  71                                    struct iscsi_segment *segment);
  72
  73 /*
  74  * Scatterlist handling: inside the iscsi_segment, we
  75  * remember an index into the scatterlist, and set data/size
  76  * to the current scatterlist entry. For highmem pages, we
  77  * kmap as needed.
  78  *
  79  * Note that the page is unmapped when we return from
  80  * TCP's data_ready handler, so we may end up mapping and
  81  * unmapping the same page repeatedly. The whole reason
  82  * for this is that we shouldn't keep the page mapped
  83  * outside the softirq.
  84  */
  85
  86 /**
  87  * iscsi_tcp_segment_init_sg - init indicated scatterlist entry
  88  * @segment: the buffer object
  89  * @sg: scatterlist
  90  * @offset: byte offset into that sg entry
  91  *
  92  * This function sets up the segment so that subsequent
  93  * data is copied to the indicated sg entry, at the given
  94  * offset.
  95  */
  96 static inline void
  97 iscsi_tcp_segment_init_sg(struct iscsi_segment *segment,
  98                           struct scatterlist *sg, unsigned int offset)
  99 {
 100         segment->sg = sg;
 101         segment->sg_offset = offset;
 102         segment->size = min(sg->length - offset,
 103                             segment->total_size - segment->total_copied);
 104         segment->data = NULL;
 105 }
 106
 107 /**
 108  * iscsi_tcp_segment_map - map the current S/G page
 109  * @segment: iscsi_segment
 110  * @recv: 1 if called from recv path
 111  *
 112  * We only need to possibly kmap data if scatter lists are being used,
 113  * because the iscsi passthrough and internal IO paths will never use high
 114  * mem pages.
 115  */
 116 static void iscsi_tcp_segment_map(struct iscsi_segment *segment, int recv)
 117 {
 118         struct scatterlist *sg;
 119
 120         if (segment->data != NULL || !segment->sg)
 121                 return;
 122
 123         sg = segment->sg;
 124         BUG_ON(segment->sg_mapped);
 125         BUG_ON(sg->length == 0);
 126
 127         /*
 128          * If the page count is greater than one it is ok to send
 129          * to the network layer's zero copy send path. If not we
 130          * have to go the slow sendmsg path. We always map for the
 131          * recv path.
 132          */
 133         if (page_count(sg_page(sg)) >= 1 && !recv)
 134                 return;
 135
 136         if (recv) {
 137                 segment->atomic_mapped = true;
 138                 segment->sg_mapped = kmap_atomic(sg_page(sg));
 139         } else {
 140                 segment->atomic_mapped = false;
 141                 /* the xmit path can sleep with the page mapped so use kmap */
 142                 segment->sg_mapped = kmap(sg_page(sg));
 143         }
 144
 145         segment->data = segment->sg_mapped + sg->offset + segment->sg_offset;
 146 }
 147
 148 void iscsi_tcp_segment_unmap(struct iscsi_segment *segment)
 149 {
 150         if (segment->sg_mapped) {
 151                 if (segment->atomic_mapped)
 152                         kunmap_atomic(segment->sg_mapped);
 153                 else
 154                         kunmap(sg_page(segment->sg));
 155                 segment->sg_mapped = NULL;
 156                 segment->data = NULL;
 157         }
 158 }
 159 EXPORT_SYMBOL_GPL(iscsi_tcp_segment_unmap);
 160
 161 /*
 162  * Splice the digest buffer into the buffer
 163  */
 164 static inline void
 165 iscsi_tcp_segment_splice_digest(struct iscsi_segment *segment, void *digest)
 166 {
 167         segment->data = digest;
 168         segment->digest_len = ISCSI_DIGEST_SIZE;
 169         segment->total_size += ISCSI_DIGEST_SIZE;
 170         segment->size = ISCSI_DIGEST_SIZE;
 171         segment->copied = 0;
 172         segment->sg = NULL;
 173         segment->hash = NULL;
 174 }
 175
 176 /**
 177  * iscsi_tcp_segment_done - check whether the segment is complete
 178  * @tcp_conn: iscsi tcp connection
 179  * @segment: iscsi segment to check
 180  * @recv: set to one of this is called from the recv path
 181  * @copied: number of bytes copied
 182  *
 183  * Check if we're done receiving this segment. If the receive
 184  * buffer is full but we expect more data, move on to the
 185  * next entry in the scatterlist.
 186  *
 187  * If the amount of data we received isn't a multiple of 4,
 188  * we will transparently receive the pad bytes, too.
 189  *
 190  * This function must be re-entrant.
 191  */
 192 int iscsi_tcp_segment_done(struct iscsi_tcp_conn *tcp_conn,
 193                            struct iscsi_segment *segment, int recv,
 194                            unsigned copied)
 195 {
 196         struct scatterlist sg;
 197         unsigned int pad;
 198
 199         ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "copied %u %u size %u %s\n",
 200                       segment->copied, copied, segment->size,
 201                       recv ? "recv" : "xmit");
 202         if (segment->hash && copied) {
 203                 /*
 204                  * If a segment is kmapd we must unmap it before sending
 205                  * to the crypto layer since that will try to kmap it again.
 206                  */
 207                 iscsi_tcp_segment_unmap(segment);
 208
 209                 if (!segment->data) {
 210                         sg_init_table(&sg, 1);
 211                         sg_set_page(&sg, sg_page(segment->sg), copied,
 212                                     segment->copied + segment->sg_offset +
 213                                                         segment->sg->offset);
 214                 } else
 215                         sg_init_one(&sg, segment->data + segment->copied,
 216                                     copied);
 217                 crypto_hash_update(segment->hash, &sg, copied);
 218         }
 219
 220         segment->copied += copied;
 221         if (segment->copied < segment->size) {
 222                 iscsi_tcp_segment_map(segment, recv);
 223                 return 0;
 224         }
 225
 226         segment->total_copied += segment->copied;
 227         segment->copied = 0;
 228         segment->size = 0;
 229
 230         /* Unmap the current scatterlist page, if there is one. */
 231         iscsi_tcp_segment_unmap(segment);
 232
 233         /* Do we have more scatterlist entries? */
 234         ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "total copied %u total size %u\n",
 235                       segment->total_copied, segment->total_size);
 236         if (segment->total_copied < segment->total_size) {
 237                 /* Proceed to the next entry in the scatterlist. */
 238                 iscsi_tcp_segment_init_sg(segment, sg_next(segment->sg),
 239                                           0);
 240                 iscsi_tcp_segment_map(segment, recv);
 241                 BUG_ON(segment->size == 0);
 242                 return 0;
 243         }
 244
 245         /* Do we need to handle padding? */
 246         if (!(tcp_conn->iscsi_conn->session->tt->caps & CAP_PADDING_OFFLOAD)) {
 247                 pad = iscsi_padding(segment->total_copied);
 248                 if (pad != 0) {
 249                         ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
 250                                       "consume %d pad bytes\n", pad);
 251                         segment->total_size += pad;
 252                         segment->size = pad;
 253                         segment->data = segment->padbuf;
 254                         return 0;
 255                 }
 256         }
 257
 258         /*
 259          * Set us up for transferring the data digest. hdr digest
 260          * is completely handled in hdr done function.
 261          */
 262         if (segment->hash) {
 263                 crypto_hash_final(segment->hash, segment->digest);
 264                 iscsi_tcp_segment_splice_digest(segment,
 265                                  recv ? segment->recv_digest : segment->digest);
 266                 return 0;
 267         }
 268
 269         return 1;
 270 }
 271 EXPORT_SYMBOL_GPL(iscsi_tcp_segment_done);
 272
 273 /**
 274  * iscsi_tcp_segment_recv - copy data to segment
 275  * @tcp_conn: the iSCSI TCP connection
 276  * @segment: the buffer to copy to
 277  * @ptr: data pointer
 278  * @len: amount of data available
 279  *
 280  * This function copies up to @len bytes to the
 281  * given buffer, and returns the number of bytes
 282  * consumed, which can actually be less than @len.
 283  *
 284  * If hash digest is enabled, the function will update the
 285  * hash while copying.
 286  * Combining these two operations doesn't buy us a lot (yet),
 287  * but in the future we could implement combined copy+crc,
 288  * just way we do for network layer checksums.
 289  */
 290 static int
 291 iscsi_tcp_segment_recv(struct iscsi_tcp_conn *tcp_conn,
 292                        struct iscsi_segment *segment, const void *ptr,
 293                        unsigned int len)
 294 {
 295         unsigned int copy = 0, copied = 0;
 296
 297         while (!iscsi_tcp_segment_done(tcp_conn, segment, 1, copy)) {
 298                 if (copied == len) {
 299                         ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
 300                                       "copied %d bytes\n", len);
 301                         break;
 302                 }
 303
 304                 copy = min(len - copied, segment->size - segment->copied);
 305                 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "copying %d\n", copy);
 306                 memcpy(segment->data + segment->copied, ptr + copied, copy);
 307                 copied += copy;
 308         }
 309         return copied;
 310 }
 311
 312 inline void
 313 iscsi_tcp_dgst_header(struct hash_desc *hash, const void *hdr, size_t hdrlen,
 314                       unsigned char digest[ISCSI_DIGEST_SIZE])
 315 {
 316         struct scatterlist sg;
 317
 318         sg_init_one(&sg, hdr, hdrlen);
 319         crypto_hash_digest(hash, &sg, hdrlen, digest);
 320 }
 321 EXPORT_SYMBOL_GPL(iscsi_tcp_dgst_header);
 322
 323 static inline int
 324 iscsi_tcp_dgst_verify(struct iscsi_tcp_conn *tcp_conn,
 325                       struct iscsi_segment *segment)
 326 {
 327         if (!segment->digest_len)
 328                 return 1;
 329
 330         if (memcmp(segment->recv_digest, segment->digest,
 331                    segment->digest_len)) {
 332                 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "digest mismatch\n");
 333                 return 0;
 334         }
 335
 336         return 1;
 337 }
 338
 339 /*
 340  * Helper function to set up segment buffer
 341  */
 342 static inline void
 343 __iscsi_segment_init(struct iscsi_segment *segment, size_t size,
 344                      iscsi_segment_done_fn_t *done, struct hash_desc *hash)
 345 {
 346         memset(segment, 0, sizeof(*segment));
 347         segment->total_size = size;
 348         segment->done = done;
 349
 350         if (hash) {
 351                 segment->hash = hash;
 352                 crypto_hash_init(hash);
 353         }
 354 }
 355
 356 inline void
 357 iscsi_segment_init_linear(struct iscsi_segment *segment, void *data,
 358                           size_t size, iscsi_segment_done_fn_t *done,
 359                           struct hash_desc *hash)
 360 {
 361         __iscsi_segment_init(segment, size, done, hash);
 362         segment->data = data;
 363         segment->size = size;
 364 }
 365 EXPORT_SYMBOL_GPL(iscsi_segment_init_linear);
 366
 367 inline int
 368 iscsi_segment_seek_sg(struct iscsi_segment *segment,
 369                       struct scatterlist *sg_list, unsigned int sg_count,
 370                       unsigned int offset, size_t size,
 371                       iscsi_segment_done_fn_t *done, struct hash_desc *hash)
 372 {
 373         struct scatterlist *sg;
 374         unsigned int i;
 375
 376         __iscsi_segment_init(segment, size, done, hash);
 377         for_each_sg(sg_list, sg, sg_count, i) {
 378                 if (offset < sg->length) {
 379                         iscsi_tcp_segment_init_sg(segment, sg, offset);
 380                         return 0;
 381                 }
 382                 offset -= sg->length;
 383         }
 384
 385         return ISCSI_ERR_DATA_OFFSET;
 386 }
 387 EXPORT_SYMBOL_GPL(iscsi_segment_seek_sg);
 388
 389 /**
 390  * iscsi_tcp_hdr_recv_prep - prep segment for hdr reception
 391  * @tcp_conn: iscsi connection to prep for
 392  *
 393  * This function always passes NULL for the hash argument, because when this
 394  * function is called we do not yet know the final size of the header and want
 395  * to delay the digest processing until we know that.
 396  */
 397 void iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn)
 398 {
 399         ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
 400                       "(%s)\n", tcp_conn->iscsi_conn->hdrdgst_en ?
 401                       "digest enabled" : "digest disabled");
 402         iscsi_segment_init_linear(&tcp_conn->in.segment,
 403                                 tcp_conn->in.hdr_buf, sizeof(struct iscsi_hdr),
 404                                 iscsi_tcp_hdr_recv_done, NULL);
 405 }
 406 EXPORT_SYMBOL_GPL(iscsi_tcp_hdr_recv_prep);
 407
 408 /*
 409  * Handle incoming reply to any other type of command
 410  */
 411 static int
 412 iscsi_tcp_data_recv_done(struct iscsi_tcp_conn *tcp_conn,
 413                          struct iscsi_segment *segment)
 414 {
 415         struct iscsi_conn *conn = tcp_conn->iscsi_conn;
 416         int rc = 0;
 417
 418         if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
 419                 return ISCSI_ERR_DATA_DGST;
 420
 421         rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr,
 422                         conn->data, tcp_conn->in.datalen);
 423         if (rc)
 424                 return rc;
 425
 426         iscsi_tcp_hdr_recv_prep(tcp_conn);
 427         return 0;
 428 }
 429
 430 static void
 431 iscsi_tcp_data_recv_prep(struct iscsi_tcp_conn *tcp_conn)
 432 {
 433         struct iscsi_conn *conn = tcp_conn->iscsi_conn;
 434         struct hash_desc *rx_hash = NULL;
 435
 436         if (conn->datadgst_en &&
 437             !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
 438                 rx_hash = tcp_conn->rx_hash;
 439
 440         iscsi_segment_init_linear(&tcp_conn->in.segment,
 441                                 conn->data, tcp_conn->in.datalen,
 442                                 iscsi_tcp_data_recv_done, rx_hash);
 443 }
 444
 445 /**
 446  * iscsi_tcp_cleanup_task - free tcp_task resources
 447  * @task: iscsi task
 448  *
 449  * must be called with session back_lock
 450  */
 451 void iscsi_tcp_cleanup_task(struct iscsi_task *task)
 452 {
 453         struct iscsi_tcp_task *tcp_task = task->dd_data;
 454         struct iscsi_r2t_info *r2t;
 455
 456         /* nothing to do for mgmt */
 457         if (!task->sc)
 458                 return;
 459
 460         spin_lock_bh(&tcp_task->queue2pool);
 461         /* flush task's r2t queues */
 462         while (kfifo_out(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*))) {
 463                 kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
 464                             sizeof(void*));
 465                 ISCSI_DBG_TCP(task->conn, "pending r2t dropped\n");
 466         }
 467
 468         r2t = tcp_task->r2t;
 469         if (r2t != NULL) {
 470                 kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
 471                             sizeof(void*));
 472                 tcp_task->r2t = NULL;
 473         }
 474         spin_unlock_bh(&tcp_task->queue2pool);
 475 }
 476 EXPORT_SYMBOL_GPL(iscsi_tcp_cleanup_task);
 477
 478 /**
 479  * iscsi_tcp_data_in - SCSI Data-In Response processing
 480  * @conn: iscsi connection
 481  * @task: scsi command task
 482  */
 483 static int iscsi_tcp_data_in(struct iscsi_conn *conn, struct iscsi_task *task)
 484 {
 485         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 486         struct iscsi_tcp_task *tcp_task = task->dd_data;
 487         struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)tcp_conn->in.hdr;
 488         int datasn = be32_to_cpu(rhdr->datasn);
 489         unsigned total_in_length = scsi_in(task->sc)->length;
 490
 491         /*
 492          * lib iscsi will update this in the completion handling if there
 493          * is status.
 494          */
 495         if (!(rhdr->flags & ISCSI_FLAG_DATA_STATUS))
 496                 iscsi_update_cmdsn(conn->session, (struct iscsi_nopin*)rhdr);
 497
 498         if (tcp_conn->in.datalen == 0)
 499                 return 0;
 500
 501         if (tcp_task->exp_datasn != datasn) {
 502                 ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->datasn(%d)"
 503                               "\n", tcp_task->exp_datasn, datasn);
 504                 return ISCSI_ERR_DATASN;
 505         }
 506
 507         tcp_task->exp_datasn++;
 508
 509         tcp_task->data_offset = be32_to_cpu(rhdr->offset);
 510         if (tcp_task->data_offset + tcp_conn->in.datalen > total_in_length) {
 511                 ISCSI_DBG_TCP(conn, "data_offset(%d) + data_len(%d) > "
 512                               "total_length_in(%d)\n", tcp_task->data_offset,
 513                               tcp_conn->in.datalen, total_in_length);
 514                 return ISCSI_ERR_DATA_OFFSET;
 515         }
 516
 517         conn->datain_pdus_cnt++;
 518         return 0;
 519 }
 520
 521 /**
 522  * iscsi_tcp_r2t_rsp - iSCSI R2T Response processing
 523  * @conn: iscsi connection
 524  * @task: scsi command task
 525  */
 526 static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
 527 {
 528         struct iscsi_session *session = conn->session;
 529         struct iscsi_tcp_task *tcp_task = task->dd_data;
 530         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 531         struct iscsi_r2t_rsp *rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr;
 532         struct iscsi_r2t_info *r2t;
 533         int r2tsn = be32_to_cpu(rhdr->r2tsn);
 534         u32 data_length;
 535         u32 data_offset;
 536         int rc;
 537
 538         if (tcp_conn->in.datalen) {
 539                 iscsi_conn_printk(KERN_ERR, conn,
 540                                   "invalid R2t with datalen %d\n",
 541                                   tcp_conn->in.datalen);
 542                 return ISCSI_ERR_DATALEN;
 543         }
 544
 545         if (tcp_task->exp_datasn != r2tsn){
 546                 ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->r2tsn(%d)\n",
 547                               tcp_task->exp_datasn, r2tsn);
 548                 return ISCSI_ERR_R2TSN;
 549         }
 550
 551         /* fill-in new R2T associated with the task */
 552         iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr);
 553
 554         if (!task->sc || session->state != ISCSI_STATE_LOGGED_IN) {
 555                 iscsi_conn_printk(KERN_INFO, conn,
 556                                   "dropping R2T itt %d in recovery.\n",
 557                                   task->itt);
 558                 return 0;
 559         }
 560
 561         data_length = be32_to_cpu(rhdr->data_length);
 562         if (data_length == 0) {
 563                 iscsi_conn_printk(KERN_ERR, conn,
 564                                   "invalid R2T with zero data len\n");
 565                 return ISCSI_ERR_DATALEN;
 566         }
 567
 568         if (data_length > session->max_burst)
 569                 ISCSI_DBG_TCP(conn, "invalid R2T with data len %u and max "
 570                               "burst %u. Attempting to execute request.\n",
 571                               data_length, session->max_burst);
 572
 573         data_offset = be32_to_cpu(rhdr->data_offset);
 574         if (data_offset + data_length > scsi_out(task->sc)->length) {
 575                 iscsi_conn_printk(KERN_ERR, conn,
 576                                   "invalid R2T with data len %u at offset %u "
 577                                   "and total length %d\n", data_length,
 578                                   data_offset, scsi_out(task->sc)->length);
 579                 return ISCSI_ERR_DATALEN;
 580         }
 581
 582         spin_lock(&tcp_task->pool2queue);
 583         rc = kfifo_out(&tcp_task->r2tpool.queue, (void *)&r2t, sizeof(void *));
 584         if (!rc) {
 585                 iscsi_conn_printk(KERN_ERR, conn, "Could not allocate R2T. "
 586                                   "Target has sent more R2Ts than it "
 587                                   "negotiated for or driver has leaked.\n");
 588                 spin_unlock(&tcp_task->pool2queue);
 589                 return ISCSI_ERR_PROTO;
 590         }
 591
 592         r2t->exp_statsn = rhdr->statsn;
 593         r2t->data_length = data_length;
 594         r2t->data_offset = data_offset;
 595
 596         r2t->ttt = rhdr->ttt; /* no flip */
 597         r2t->datasn = 0;
 598         r2t->sent = 0;
 599
 600         tcp_task->exp_datasn = r2tsn + 1;
 601         kfifo_in(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*));
 602         conn->r2t_pdus_cnt++;
 603         spin_unlock(&tcp_task->pool2queue);
 604
 605         iscsi_requeue_task(task);
 606         return 0;
 607 }
 608
 609 /*
 610  * Handle incoming reply to DataIn command
 611  */
 612 static int
 613 iscsi_tcp_process_data_in(struct iscsi_tcp_conn *tcp_conn,
 614                           struct iscsi_segment *segment)
 615 {
 616         struct iscsi_conn *conn = tcp_conn->iscsi_conn;
 617         struct iscsi_hdr *hdr = tcp_conn->in.hdr;
 618         int rc;
 619
 620         if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
 621                 return ISCSI_ERR_DATA_DGST;
 622
 623         /* check for non-exceptional status */
 624         if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
 625                 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, NULL, 0);
 626                 if (rc)
 627                         return rc;
 628         }
 629
 630         iscsi_tcp_hdr_recv_prep(tcp_conn);
 631         return 0;
 632 }
 633
 634 /**
 635  * iscsi_tcp_hdr_dissect - process PDU header
 636  * @conn: iSCSI connection
 637  * @hdr: PDU header
 638  *
 639  * This function analyzes the header of the PDU received,
 640  * and performs several sanity checks. If the PDU is accompanied
 641  * by data, the receive buffer is set up to copy the incoming data
 642  * to the correct location.
 643  */
 644 static int
 645 iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
 646 {
 647         int rc = 0, opcode, ahslen;
 648         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 649         struct iscsi_task *task;
 650
 651         /* verify PDU length */
 652         tcp_conn->in.datalen = ntoh24(hdr->dlength);
 653         if (tcp_conn->in.datalen > conn->max_recv_dlength) {
 654                 iscsi_conn_printk(KERN_ERR, conn,
 655                                   "iscsi_tcp: datalen %d > %d\n",
 656                                   tcp_conn->in.datalen, conn->max_recv_dlength);
 657                 return ISCSI_ERR_DATALEN;
 658         }
 659
 660         /* Additional header segments. So far, we don't
 661          * process additional headers.
 662          */
 663         ahslen = hdr->hlength << 2;
 664
 665         opcode = hdr->opcode & ISCSI_OPCODE_MASK;
 666         /* verify itt (itt encoding: age+cid+itt) */
 667         rc = iscsi_verify_itt(conn, hdr->itt);
 668         if (rc)
 669                 return rc;
 670
 671         ISCSI_DBG_TCP(conn, "opcode 0x%x ahslen %d datalen %d\n",
 672                       opcode, ahslen, tcp_conn->in.datalen);
 673
 674         switch(opcode) {
 675         case ISCSI_OP_SCSI_DATA_IN:
 676                 spin_lock(&conn->session->back_lock);
 677                 task = iscsi_itt_to_ctask(conn, hdr->itt);
 678                 if (!task)
 679                         rc = ISCSI_ERR_BAD_ITT;
 680                 else
 681                         rc = iscsi_tcp_data_in(conn, task);
 682                 if (rc) {
 683                         spin_unlock(&conn->session->back_lock);
 684                         break;
 685                 }
 686
 687                 if (tcp_conn->in.datalen) {
 688                         struct iscsi_tcp_task *tcp_task = task->dd_data;
 689                         struct hash_desc *rx_hash = NULL;
 690                         struct scsi_data_buffer *sdb = scsi_in(task->sc);
 691
 692                         /*
 693                          * Setup copy of Data-In into the Scsi_Cmnd
 694                          * Scatterlist case:
 695                          * We set up the iscsi_segment to point to the next
 696                          * scatterlist entry to copy to. As we go along,
 697                          * we move on to the next scatterlist entry and
 698                          * update the digest per-entry.
 699                          */
 700                         if (conn->datadgst_en &&
 701                             !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
 702                                 rx_hash = tcp_conn->rx_hash;
 703
 704                         ISCSI_DBG_TCP(conn, "iscsi_tcp_begin_data_in( "
 705                                      "offset=%d, datalen=%d)\n",
 706                                       tcp_task->data_offset,
 707                                       tcp_conn->in.datalen);
 708                         task->last_xfer = jiffies;
 709                         rc = iscsi_segment_seek_sg(&tcp_conn->in.segment,
 710                                                    sdb->table.sgl,
 711                                                    sdb->table.nents,
 712                                                    tcp_task->data_offset,
 713                                                    tcp_conn->in.datalen,
 714                                                    iscsi_tcp_process_data_in,
 715                                                    rx_hash);
 716                         spin_unlock(&conn->session->back_lock);
 717                         return rc;
 718                 }
 719                 rc = __iscsi_complete_pdu(conn, hdr, NULL, 0);
 720                 spin_unlock(&conn->session->back_lock);
 721                 break;
 722         case ISCSI_OP_SCSI_CMD_RSP:
 723                 if (tcp_conn->in.datalen) {
 724                         iscsi_tcp_data_recv_prep(tcp_conn);
 725                         return 0;
 726                 }
 727                 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
 728                 break;
 729         case ISCSI_OP_R2T:
 730                 spin_lock(&conn->session->back_lock);
 731                 task = iscsi_itt_to_ctask(conn, hdr->itt);
 732                 spin_unlock(&conn->session->back_lock);
 733                 if (!task)
 734                         rc = ISCSI_ERR_BAD_ITT;
 735                 else if (ahslen)
 736                         rc = ISCSI_ERR_AHSLEN;
 737                 else if (task->sc->sc_data_direction == DMA_TO_DEVICE) {
 738                         task->last_xfer = jiffies;
 739                         spin_lock(&conn->session->frwd_lock);
 740                         rc = iscsi_tcp_r2t_rsp(conn, task);
 741                         spin_unlock(&conn->session->frwd_lock);
 742                 } else
 743                         rc = ISCSI_ERR_PROTO;
 744                 break;
 745         case ISCSI_OP_LOGIN_RSP:
 746         case ISCSI_OP_TEXT_RSP:
 747         case ISCSI_OP_REJECT:
 748         case ISCSI_OP_ASYNC_EVENT:
 749                 /*
 750                  * It is possible that we could get a PDU with a buffer larger
 751                  * than 8K, but there are no targets that currently do this.
 752                  * For now we fail until we find a vendor that needs it
 753                  */
 754                 if (ISCSI_DEF_MAX_RECV_SEG_LEN < tcp_conn->in.datalen) {
 755                         iscsi_conn_printk(KERN_ERR, conn,
 756                                           "iscsi_tcp: received buffer of "
 757                                           "len %u but conn buffer is only %u "
 758                                           "(opcode %0x)\n",
 759                                           tcp_conn->in.datalen,
 760                                           ISCSI_DEF_MAX_RECV_SEG_LEN, opcode);
 761                         rc = ISCSI_ERR_PROTO;
 762                         break;
 763                 }
 764
 765                 /* If there's data coming in with the response,
 766                  * receive it to the connection's buffer.
 767                  */
 768                 if (tcp_conn->in.datalen) {
 769                         iscsi_tcp_data_recv_prep(tcp_conn);
 770                         return 0;
 771                 }
 772         /* fall through */
 773         case ISCSI_OP_LOGOUT_RSP:
 774         case ISCSI_OP_NOOP_IN:
 775         case ISCSI_OP_SCSI_TMFUNC_RSP:
 776                 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
 777                 break;
 778         default:
 779                 rc = ISCSI_ERR_BAD_OPCODE;
 780                 break;
 781         }
 782
 783         if (rc == 0) {
 784                 /* Anything that comes with data should have
 785                  * been handled above. */
 786                 if (tcp_conn->in.datalen)
 787                         return ISCSI_ERR_PROTO;
 788                 iscsi_tcp_hdr_recv_prep(tcp_conn);
 789         }
 790
 791         return rc;
 792 }
 793
 794 /**
 795  * iscsi_tcp_hdr_recv_done - process PDU header
 796  *
 797  * This is the callback invoked when the PDU header has
 798  * been received. If the header is followed by additional
 799  * header segments, we go back for more data.
 800  */
 801 static int
 802 iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
 803                         struct iscsi_segment *segment)
 804 {
 805         struct iscsi_conn *conn = tcp_conn->iscsi_conn;
 806         struct iscsi_hdr *hdr;
 807
 808         /* Check if there are additional header segments
 809          * *prior* to computing the digest, because we
 810          * may need to go back to the caller for more.
 811          */
 812         hdr = (struct iscsi_hdr *) tcp_conn->in.hdr_buf;
 813         if (segment->copied == sizeof(struct iscsi_hdr) && hdr->hlength) {
 814                 /* Bump the header length - the caller will
 815                  * just loop around and get the AHS for us, and
 816                  * call again. */
 817                 unsigned int ahslen = hdr->hlength << 2;
 818
 819                 /* Make sure we don't overflow */
 820                 if (sizeof(*hdr) + ahslen > sizeof(tcp_conn->in.hdr_buf))
 821                         return ISCSI_ERR_AHSLEN;
 822
 823                 segment->total_size += ahslen;
 824                 segment->size += ahslen;
 825                 return 0;
 826         }
 827
 828         /* We're done processing the header. See if we're doing
 829          * header digests; if so, set up the recv_digest buffer
 830          * and go back for more. */
 831         if (conn->hdrdgst_en &&
 832             !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD)) {
 833                 if (segment->digest_len == 0) {
 834                         /*
 835                          * Even if we offload the digest processing we
 836                          * splice it in so we can increment the skb/segment
 837                          * counters in preparation for the data segment.
 838                          */
 839                         iscsi_tcp_segment_splice_digest(segment,
 840                                                         segment->recv_digest);
 841                         return 0;
 842                 }
 843
 844                 iscsi_tcp_dgst_header(tcp_conn->rx_hash, hdr,
 845                                       segment->total_copied - ISCSI_DIGEST_SIZE,
 846                                       segment->digest);
 847
 848                 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
 849                         return ISCSI_ERR_HDR_DGST;
 850         }
 851
 852         tcp_conn->in.hdr = hdr;
 853         return iscsi_tcp_hdr_dissect(conn, hdr);
 854 }
 855
 856 /**
 857  * iscsi_tcp_recv_segment_is_hdr - tests if we are reading in a header
 858  * @tcp_conn: iscsi tcp conn
 859  *
 860  * returns non zero if we are currently processing or setup to process
 861  * a header.
 862  */
 863 inline int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn)
 864 {
 865         return tcp_conn->in.segment.done == iscsi_tcp_hdr_recv_done;
 866 }
 867 EXPORT_SYMBOL_GPL(iscsi_tcp_recv_segment_is_hdr);
 868
 869 /**
 870  * iscsi_tcp_recv_skb - Process skb
 871  * @conn: iscsi connection
 872  * @skb: network buffer with header and/or data segment
 873  * @offset: offset in skb
 874  * @offload: bool indicating if transfer was offloaded
 875  *
 876  * Will return status of transfer in status. And will return
 877  * number of bytes copied.
 878  */
 879 int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
 880                        unsigned int offset, bool offloaded, int *status)
 881 {
 882         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 883         struct iscsi_segment *segment = &tcp_conn->in.segment;
 884         struct skb_seq_state seq;
 885         unsigned int consumed = 0;
 886         int rc = 0;
 887
 888         ISCSI_DBG_TCP(conn, "in %d bytes\n", skb->len - offset);
 889         /*
 890          * Update for each skb instead of pdu, because over slow networks a
 891          * data_in's data could take a while to read in. We also want to
 892          * account for r2ts.
 893          */
 894         conn->last_recv = jiffies;
 895
 896         if (unlikely(conn->suspend_rx)) {
 897                 ISCSI_DBG_TCP(conn, "Rx suspended!\n");
 898                 *status = ISCSI_TCP_SUSPENDED;
 899                 return 0;
 900         }
 901
 902         if (offloaded) {
 903                 segment->total_copied = segment->total_size;
 904                 goto segment_done;
 905         }
 906
 907         skb_prepare_seq_read(skb, offset, skb->len, &seq);
 908         while (1) {
 909                 unsigned int avail;
 910                 const u8 *ptr;
 911
 912                 avail = skb_seq_read(consumed, &ptr, &seq);
 913                 if (avail == 0) {
 914                         ISCSI_DBG_TCP(conn, "no more data avail. Consumed %d\n",
 915                                       consumed);
 916                         *status = ISCSI_TCP_SKB_DONE;
 917                         goto skb_done;
 918                 }
 919                 BUG_ON(segment->copied >= segment->size);
 920
 921                 ISCSI_DBG_TCP(conn, "skb %p ptr=%p avail=%u\n", skb, ptr,
 922                               avail);
 923                 rc = iscsi_tcp_segment_recv(tcp_conn, segment, ptr, avail);
 924                 BUG_ON(rc == 0);
 925                 consumed += rc;
 926
 927                 if (segment->total_copied >= segment->total_size) {
 928                         skb_abort_seq_read(&seq);
 929                         goto segment_done;
 930                 }
 931         }
 932
 933 segment_done:
 934         *status = ISCSI_TCP_SEGMENT_DONE;
 935         ISCSI_DBG_TCP(conn, "segment done\n");
 936         rc = segment->done(tcp_conn, segment);
 937         if (rc != 0) {
 938                 *status = ISCSI_TCP_CONN_ERR;
 939                 ISCSI_DBG_TCP(conn, "Error receiving PDU, errno=%d\n", rc);
 940                 iscsi_conn_failure(conn, rc);
 941                 return 0;
 942         }
 943         /* The done() functions sets up the next segment. */
 944
 945 skb_done:
 946         conn->rxdata_octets += consumed;
 947         return consumed;
 948 }
 949 EXPORT_SYMBOL_GPL(iscsi_tcp_recv_skb);
 950
 951 /**
 952  * iscsi_tcp_task_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
 953  * @conn: iscsi connection
 954  * @task: scsi command task
 955  * @sc: scsi command
 956  */
 957 int iscsi_tcp_task_init(struct iscsi_task *task)
 958 {
 959         struct iscsi_tcp_task *tcp_task = task->dd_data;
 960         struct iscsi_conn *conn = task->conn;
 961         struct scsi_cmnd *sc = task->sc;
 962         int err;
 963
 964         if (!sc) {
 965                 /*
 966                  * mgmt tasks do not have a scatterlist since they come
 967                  * in from the iscsi interface.
 968                  */
 969                 ISCSI_DBG_TCP(conn, "mtask deq [itt 0x%x]\n", task->itt);
 970
 971                 return conn->session->tt->init_pdu(task, 0, task->data_count);
 972         }
 973
 974         BUG_ON(kfifo_len(&tcp_task->r2tqueue));
 975         tcp_task->exp_datasn = 0;
 976
 977         /* Prepare PDU, optionally w/ immediate data */
 978         ISCSI_DBG_TCP(conn, "task deq [itt 0x%x imm %d unsol %d]\n",
 979                       task->itt, task->imm_count, task->unsol_r2t.data_length);
 980
 981         err = conn->session->tt->init_pdu(task, 0, task->imm_count);
 982         if (err)
 983                 return err;
 984         task->imm_count = 0;
 985         return 0;
 986 }
 987 EXPORT_SYMBOL_GPL(iscsi_tcp_task_init);
 988
 989 static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
 990 {
 991         struct iscsi_tcp_task *tcp_task = task->dd_data;
 992         struct iscsi_r2t_info *r2t = NULL;
 993
 994         if (iscsi_task_has_unsol_data(task))
 995                 r2t = &task->unsol_r2t;
 996         else {
 997                 spin_lock_bh(&tcp_task->queue2pool);
 998                 if (tcp_task->r2t) {
 999                         r2t = tcp_task->r2t;
1000                         /* Continue with this R2T? */
1001                         if (r2t->data_length <= r2t->sent) {
1002                                 ISCSI_DBG_TCP(task->conn,
1003                                               "  done with r2t %p\n", r2t);
1004                                 kfifo_in(&tcp_task->r2tpool.queue,
1005                                             (void *)&tcp_task->r2t,
1006                                             sizeof(void *));
1007                                 tcp_task->r2t = r2t = NULL;
1008                         }
1009                 }
1010
1011                 if (r2t == NULL) {
1012                         if (kfifo_out(&tcp_task->r2tqueue,
1013                             (void *)&tcp_task->r2t, sizeof(void *)) !=
1014                             sizeof(void *))
1015                                 r2t = NULL;
1016                         else
1017                                 r2t = tcp_task->r2t;
1018                 }
1019                 spin_unlock_bh(&tcp_task->queue2pool);
1020         }
1021
1022         return r2t;
1023 }
1024
1025 /**
1026  * iscsi_tcp_task_xmit - xmit normal PDU task
1027  * @task: iscsi command task
1028  *
1029  * We're expected to return 0 when everything was transmitted successfully,
1030  * -EAGAIN if there's still data in the queue, or != 0 for any other kind
1031  * of error.
1032  */
1033 int iscsi_tcp_task_xmit(struct iscsi_task *task)
1034 {
1035         struct iscsi_conn *conn = task->conn;
1036         struct iscsi_session *session = conn->session;
1037         struct iscsi_r2t_info *r2t;
1038         int rc = 0;
1039
1040 flush:
1041         /* Flush any pending data first. */
1042         rc = session->tt->xmit_pdu(task);
1043         if (rc < 0)
1044                 return rc;
1045
1046         /* mgmt command */
1047         if (!task->sc) {
1048                 if (task->hdr->itt == RESERVED_ITT)
1049                         iscsi_put_task(task);
1050                 return 0;
1051         }
1052
1053         /* Are we done already? */
1054         if (task->sc->sc_data_direction != DMA_TO_DEVICE)
1055                 return 0;
1056
1057         r2t = iscsi_tcp_get_curr_r2t(task);
1058         if (r2t == NULL) {
1059                 /* Waiting for more R2Ts to arrive. */
1060                 ISCSI_DBG_TCP(conn, "no R2Ts yet\n");
1061                 return 0;
1062         }
1063
1064         rc = conn->session->tt->alloc_pdu(task, ISCSI_OP_SCSI_DATA_OUT);
1065         if (rc)
1066                 return rc;
1067         iscsi_prep_data_out_pdu(task, r2t, (struct iscsi_data *) task->hdr);
1068
1069         ISCSI_DBG_TCP(conn, "sol dout %p [dsn %d itt 0x%x doff %d dlen %d]\n",
1070                       r2t, r2t->datasn - 1, task->hdr->itt,
1071                       r2t->data_offset + r2t->sent, r2t->data_count);
1072
1073         rc = conn->session->tt->init_pdu(task, r2t->data_offset + r2t->sent,
1074                                          r2t->data_count);
1075         if (rc) {
1076                 iscsi_conn_failure(conn, ISCSI_ERR_XMIT_FAILED);
1077                 return rc;
1078         }
1079
1080         r2t->sent += r2t->data_count;
1081         goto flush;
1082 }
1083 EXPORT_SYMBOL_GPL(iscsi_tcp_task_xmit);
1084
1085 struct iscsi_cls_conn *
1086 iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
1087                       uint32_t conn_idx)
1088
1089 {
1090         struct iscsi_conn *conn;
1091         struct iscsi_cls_conn *cls_conn;
1092         struct iscsi_tcp_conn *tcp_conn;
1093
1094         cls_conn = iscsi_conn_setup(cls_session,
1095                                     sizeof(*tcp_conn) + dd_data_size, conn_idx);
1096         if (!cls_conn)
1097                 return NULL;
1098         conn = cls_conn->dd_data;
1099         /*
1100          * due to strange issues with iser these are not set
1101          * in iscsi_conn_setup
1102          */
1103         conn->max_recv_dlength = ISCSI_DEF_MAX_RECV_SEG_LEN;
1104
1105         tcp_conn = conn->dd_data;
1106         tcp_conn->iscsi_conn = conn;
1107         tcp_conn->dd_data = conn->dd_data + sizeof(*tcp_conn);
1108         return cls_conn;
1109 }
1110 EXPORT_SYMBOL_GPL(iscsi_tcp_conn_setup);
1111
1112 void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn)
1113 {
1114         iscsi_conn_teardown(cls_conn);
1115 }
1116 EXPORT_SYMBOL_GPL(iscsi_tcp_conn_teardown);
1117
1118 int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session)
1119 {
1120         int i;
1121         int cmd_i;
1122
1123         /*
1124          * initialize per-task: R2T pool and xmit queue
1125          */
1126         for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
1127                 struct iscsi_task *task = session->cmds[cmd_i];
1128                 struct iscsi_tcp_task *tcp_task = task->dd_data;
1129
1130                 /*
1131                  * pre-allocated x2 as much r2ts to handle race when
1132                  * target acks DataOut faster than we data_xmit() queues
1133                  * could replenish r2tqueue.
1134                  */
1135
1136                 /* R2T pool */
1137                 if (iscsi_pool_init(&tcp_task->r2tpool,
1138                                     session->max_r2t * 2, NULL,
1139                                     sizeof(struct iscsi_r2t_info))) {
1140                         goto r2t_alloc_fail;
1141                 }
1142
1143                 /* R2T xmit queue */
1144                 if (kfifo_alloc(&tcp_task->r2tqueue,
1145                       session->max_r2t * 4 * sizeof(void*), GFP_KERNEL)) {
1146                         iscsi_pool_free(&tcp_task->r2tpool);
1147                         goto r2t_alloc_fail;
1148                 }
1149                 spin_lock_init(&tcp_task->pool2queue);
1150                 spin_lock_init(&tcp_task->queue2pool);
1151         }
1152
1153         return 0;
1154
1155 r2t_alloc_fail:
1156         for (i = 0; i < cmd_i; i++) {
1157                 struct iscsi_task *task = session->cmds[i];
1158                 struct iscsi_tcp_task *tcp_task = task->dd_data;
1159
1160                 kfifo_free(&tcp_task->r2tqueue);
1161                 iscsi_pool_free(&tcp_task->r2tpool);
1162         }
1163         return -ENOMEM;
1164 }
1165 EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_alloc);
1166
1167 void iscsi_tcp_r2tpool_free(struct iscsi_session *session)
1168 {
1169         int i;
1170
1171         for (i = 0; i < session->cmds_max; i++) {
1172                 struct iscsi_task *task = session->cmds[i];
1173                 struct iscsi_tcp_task *tcp_task = task->dd_data;
1174
1175                 kfifo_free(&tcp_task->r2tqueue);
1176                 iscsi_pool_free(&tcp_task->r2tpool);
1177         }
1178 }
1179 EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_free);
1180
1181 int iscsi_tcp_set_max_r2t(struct iscsi_conn *conn, char *buf)
1182 {
1183         struct iscsi_session *session = conn->session;
1184         unsigned short r2ts = 0;
1185
1186         sscanf(buf, "%hu", &r2ts);
1187         if (session->max_r2t == r2ts)
1188                 return 0;
1189
1190         if (!r2ts || !is_power_of_2(r2ts))
1191                 return -EINVAL;
1192
1193         session->max_r2t = r2ts;
1194         iscsi_tcp_r2tpool_free(session);
1195         return iscsi_tcp_r2tpool_alloc(session);
1196 }
1197 EXPORT_SYMBOL_GPL(iscsi_tcp_set_max_r2t);
1198
1199 void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
1200                               struct iscsi_stats *stats)
1201 {
1202         struct iscsi_conn *conn = cls_conn->dd_data;
1203
1204         stats->txdata_octets = conn->txdata_octets;
1205         stats->rxdata_octets = conn->rxdata_octets;
1206         stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
1207         stats->dataout_pdus = conn->dataout_pdus_cnt;
1208         stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
1209         stats->datain_pdus = conn->datain_pdus_cnt;
1210         stats->r2t_pdus = conn->r2t_pdus_cnt;
1211         stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
1212         stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
1213 }
1214 EXPORT_SYMBOL_GPL(iscsi_tcp_conn_get_stats);