drivers/scsi/libiscsi_tcp.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * iSCSI over TCP/IP Data-Path lib
   4  *
   5  * Copyright (C) 2004 Dmitry Yusupov
   6  * Copyright (C) 2004 Alex Aizman
   7  * Copyright (C) 2005 - 2006 Mike Christie
   8  * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
   9  * maintained by open-iscsi@googlegroups.com
  10  *
  11  * Credits:
  12  *      Christoph Hellwig
  13  *      FUJITA Tomonori
  14  *      Arne Redlich
  15  *      Zhenyu Wang
  16  */
  17
  18 #include <crypto/hash.h>
  19 #include <linux/types.h>
  20 #include <linux/list.h>
  21 #include <linux/inet.h>
  22 #include <linux/slab.h>
  23 #include <linux/file.h>
  24 #include <linux/blkdev.h>
  25 #include <linux/delay.h>
  26 #include <linux/kfifo.h>
  27 #include <linux/scatterlist.h>
  28 #include <linux/module.h>
  29 #include <net/tcp.h>
  30 #include <scsi/scsi_cmnd.h>
  31 #include <scsi/scsi_device.h>
  32 #include <scsi/scsi_host.h>
  33 #include <scsi/scsi.h>
  34 #include <scsi/scsi_transport_iscsi.h>
  35 #include <trace/events/iscsi.h>
  36
  37 #include "iscsi_tcp.h"
  38
  39 MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, "
  40               "Dmitry Yusupov <dmitry_yus@yahoo.com>, "
  41               "Alex Aizman <itn780@yahoo.com>");
  42 MODULE_DESCRIPTION("iSCSI/TCP data-path");
  43 MODULE_LICENSE("GPL");
  44
  45 static int iscsi_dbg_libtcp;
  46 module_param_named(debug_libiscsi_tcp, iscsi_dbg_libtcp, int,
  47                    S_IRUGO | S_IWUSR);
  48 MODULE_PARM_DESC(debug_libiscsi_tcp, "Turn on debugging for libiscsi_tcp "
  49                  "module. Set to 1 to turn on, and zero to turn off. Default "
  50                  "is off.");
  51
  52 #define ISCSI_DBG_TCP(_conn, dbg_fmt, arg...)                   \
  53         do {                                                    \
  54                 if (iscsi_dbg_libtcp)                           \
  55                         iscsi_conn_printk(KERN_INFO, _conn,     \
  56                                              "%s " dbg_fmt,     \
  57                                              __func__, ##arg);  \
  58                 iscsi_dbg_trace(trace_iscsi_dbg_tcp,            \
  59                                 &(_conn)->cls_conn->dev,        \
  60                                 "%s " dbg_fmt, __func__, ##arg);\
  61         } while (0);
  62
  63 static int iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
  64                                    struct iscsi_segment *segment);
  65
  66 /*
  67  * Scatterlist handling: inside the iscsi_segment, we
  68  * remember an index into the scatterlist, and set data/size
  69  * to the current scatterlist entry. For highmem pages, we
  70  * kmap as needed.
  71  *
  72  * Note that the page is unmapped when we return from
  73  * TCP's data_ready handler, so we may end up mapping and
  74  * unmapping the same page repeatedly. The whole reason
  75  * for this is that we shouldn't keep the page mapped
  76  * outside the softirq.
  77  */
  78
  79 /**
  80  * iscsi_tcp_segment_init_sg - init indicated scatterlist entry
  81  * @segment: the buffer object
  82  * @sg: scatterlist
  83  * @offset: byte offset into that sg entry
  84  *
  85  * This function sets up the segment so that subsequent
  86  * data is copied to the indicated sg entry, at the given
  87  * offset.
  88  */
  89 static inline void
  90 iscsi_tcp_segment_init_sg(struct iscsi_segment *segment,
  91                           struct scatterlist *sg, unsigned int offset)
  92 {
  93         segment->sg = sg;
  94         segment->sg_offset = offset;
  95         segment->size = min(sg->length - offset,
  96                             segment->total_size - segment->total_copied);
  97         segment->data = NULL;
  98 }
  99
 100 /**
 101  * iscsi_tcp_segment_map - map the current S/G page
 102  * @segment: iscsi_segment
 103  * @recv: 1 if called from recv path
 104  *
 105  * We only need to possibly kmap data if scatter lists are being used,
 106  * because the iscsi passthrough and internal IO paths will never use high
 107  * mem pages.
 108  */
 109 static void iscsi_tcp_segment_map(struct iscsi_segment *segment, int recv)
 110 {
 111         struct scatterlist *sg;
 112
 113         if (segment->data != NULL || !segment->sg)
 114                 return;
 115
 116         sg = segment->sg;
 117         BUG_ON(segment->sg_mapped);
 118         BUG_ON(sg->length == 0);
 119
 120         /*
 121          * We always map for the recv path.
 122          *
 123          * If the page count is greater than one it is ok to send
 124          * to the network layer's zero copy send path. If not we
 125          * have to go the slow sendmsg path.
 126          *
 127          * Same goes for slab pages: skb_can_coalesce() allows
 128          * coalescing neighboring slab objects into a single frag which
 129          * triggers one of hardened usercopy checks.
 130          */
 131         if (!recv && sendpage_ok(sg_page(sg)))
 132                 return;
 133
 134         if (recv) {
 135                 segment->atomic_mapped = true;
 136                 segment->sg_mapped = kmap_atomic(sg_page(sg));
 137         } else {
 138                 segment->atomic_mapped = false;
 139                 /* the xmit path can sleep with the page mapped so use kmap */
 140                 segment->sg_mapped = kmap(sg_page(sg));
 141         }
 142
 143         segment->data = segment->sg_mapped + sg->offset + segment->sg_offset;
 144 }
 145
 146 void iscsi_tcp_segment_unmap(struct iscsi_segment *segment)
 147 {
 148         if (segment->sg_mapped) {
 149                 if (segment->atomic_mapped)
 150                         kunmap_atomic(segment->sg_mapped);
 151                 else
 152                         kunmap(sg_page(segment->sg));
 153                 segment->sg_mapped = NULL;
 154                 segment->data = NULL;
 155         }
 156 }
 157 EXPORT_SYMBOL_GPL(iscsi_tcp_segment_unmap);
 158
 159 /*
 160  * Splice the digest buffer into the buffer
 161  */
 162 static inline void
 163 iscsi_tcp_segment_splice_digest(struct iscsi_segment *segment, void *digest)
 164 {
 165         segment->data = digest;
 166         segment->digest_len = ISCSI_DIGEST_SIZE;
 167         segment->total_size += ISCSI_DIGEST_SIZE;
 168         segment->size = ISCSI_DIGEST_SIZE;
 169         segment->copied = 0;
 170         segment->sg = NULL;
 171         segment->hash = NULL;
 172 }
 173
 174 /**
 175  * iscsi_tcp_segment_done - check whether the segment is complete
 176  * @tcp_conn: iscsi tcp connection
 177  * @segment: iscsi segment to check
 178  * @recv: set to one of this is called from the recv path
 179  * @copied: number of bytes copied
 180  *
 181  * Check if we're done receiving this segment. If the receive
 182  * buffer is full but we expect more data, move on to the
 183  * next entry in the scatterlist.
 184  *
 185  * If the amount of data we received isn't a multiple of 4,
 186  * we will transparently receive the pad bytes, too.
 187  *
 188  * This function must be re-entrant.
 189  */
 190 int iscsi_tcp_segment_done(struct iscsi_tcp_conn *tcp_conn,
 191                            struct iscsi_segment *segment, int recv,
 192                            unsigned copied)
 193 {
 194         struct scatterlist sg;
 195         unsigned int pad;
 196
 197         ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "copied %u %u size %u %s\n",
 198                       segment->copied, copied, segment->size,
 199                       recv ? "recv" : "xmit");
 200         if (segment->hash && copied) {
 201                 /*
 202                  * If a segment is kmapd we must unmap it before sending
 203                  * to the crypto layer since that will try to kmap it again.
 204                  */
 205                 iscsi_tcp_segment_unmap(segment);
 206
 207                 if (!segment->data) {
 208                         sg_init_table(&sg, 1);
 209                         sg_set_page(&sg, sg_page(segment->sg), copied,
 210                                     segment->copied + segment->sg_offset +
 211                                                         segment->sg->offset);
 212                 } else
 213                         sg_init_one(&sg, segment->data + segment->copied,
 214                                     copied);
 215                 ahash_request_set_crypt(segment->hash, &sg, NULL, copied);
 216                 crypto_ahash_update(segment->hash);
 217         }
 218
 219         segment->copied += copied;
 220         if (segment->copied < segment->size) {
 221                 iscsi_tcp_segment_map(segment, recv);
 222                 return 0;
 223         }
 224
 225         segment->total_copied += segment->copied;
 226         segment->copied = 0;
 227         segment->size = 0;
 228
 229         /* Unmap the current scatterlist page, if there is one. */
 230         iscsi_tcp_segment_unmap(segment);
 231
 232         /* Do we have more scatterlist entries? */
 233         ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "total copied %u total size %u\n",
 234                       segment->total_copied, segment->total_size);
 235         if (segment->total_copied < segment->total_size) {
 236                 /* Proceed to the next entry in the scatterlist. */
 237                 iscsi_tcp_segment_init_sg(segment, sg_next(segment->sg),
 238                                           0);
 239                 iscsi_tcp_segment_map(segment, recv);
 240                 BUG_ON(segment->size == 0);
 241                 return 0;
 242         }
 243
 244         /* Do we need to handle padding? */
 245         if (!(tcp_conn->iscsi_conn->session->tt->caps & CAP_PADDING_OFFLOAD)) {
 246                 pad = iscsi_padding(segment->total_copied);
 247                 if (pad != 0) {
 248                         ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
 249                                       "consume %d pad bytes\n", pad);
 250                         segment->total_size += pad;
 251                         segment->size = pad;
 252                         segment->data = segment->padbuf;
 253                         return 0;
 254                 }
 255         }
 256
 257         /*
 258          * Set us up for transferring the data digest. hdr digest
 259          * is completely handled in hdr done function.
 260          */
 261         if (segment->hash) {
 262                 ahash_request_set_crypt(segment->hash, NULL,
 263                                         segment->digest, 0);
 264                 crypto_ahash_final(segment->hash);
 265                 iscsi_tcp_segment_splice_digest(segment,
 266                                  recv ? segment->recv_digest : segment->digest);
 267                 return 0;
 268         }
 269
 270         return 1;
 271 }
 272 EXPORT_SYMBOL_GPL(iscsi_tcp_segment_done);
 273
 274 /**
 275  * iscsi_tcp_segment_recv - copy data to segment
 276  * @tcp_conn: the iSCSI TCP connection
 277  * @segment: the buffer to copy to
 278  * @ptr: data pointer
 279  * @len: amount of data available
 280  *
 281  * This function copies up to @len bytes to the
 282  * given buffer, and returns the number of bytes
 283  * consumed, which can actually be less than @len.
 284  *
 285  * If hash digest is enabled, the function will update the
 286  * hash while copying.
 287  * Combining these two operations doesn't buy us a lot (yet),
 288  * but in the future we could implement combined copy+crc,
 289  * just way we do for network layer checksums.
 290  */
 291 static int
 292 iscsi_tcp_segment_recv(struct iscsi_tcp_conn *tcp_conn,
 293                        struct iscsi_segment *segment, const void *ptr,
 294                        unsigned int len)
 295 {
 296         unsigned int copy = 0, copied = 0;
 297
 298         while (!iscsi_tcp_segment_done(tcp_conn, segment, 1, copy)) {
 299                 if (copied == len) {
 300                         ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
 301                                       "copied %d bytes\n", len);
 302                         break;
 303                 }
 304
 305                 copy = min(len - copied, segment->size - segment->copied);
 306                 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "copying %d\n", copy);
 307                 memcpy(segment->data + segment->copied, ptr + copied, copy);
 308                 copied += copy;
 309         }
 310         return copied;
 311 }
 312
 313 inline void
 314 iscsi_tcp_dgst_header(struct ahash_request *hash, const void *hdr,
 315                       size_t hdrlen, unsigned char digest[ISCSI_DIGEST_SIZE])
 316 {
 317         struct scatterlist sg;
 318
 319         sg_init_one(&sg, hdr, hdrlen);
 320         ahash_request_set_crypt(hash, &sg, digest, hdrlen);
 321         crypto_ahash_digest(hash);
 322 }
 323 EXPORT_SYMBOL_GPL(iscsi_tcp_dgst_header);
 324
 325 static inline int
 326 iscsi_tcp_dgst_verify(struct iscsi_tcp_conn *tcp_conn,
 327                       struct iscsi_segment *segment)
 328 {
 329         if (!segment->digest_len)
 330                 return 1;
 331
 332         if (memcmp(segment->recv_digest, segment->digest,
 333                    segment->digest_len)) {
 334                 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "digest mismatch\n");
 335                 return 0;
 336         }
 337
 338         return 1;
 339 }
 340
 341 /*
 342  * Helper function to set up segment buffer
 343  */
 344 static inline void
 345 __iscsi_segment_init(struct iscsi_segment *segment, size_t size,
 346                      iscsi_segment_done_fn_t *done, struct ahash_request *hash)
 347 {
 348         memset(segment, 0, sizeof(*segment));
 349         segment->total_size = size;
 350         segment->done = done;
 351
 352         if (hash) {
 353                 segment->hash = hash;
 354                 crypto_ahash_init(hash);
 355         }
 356 }
 357
 358 inline void
 359 iscsi_segment_init_linear(struct iscsi_segment *segment, void *data,
 360                           size_t size, iscsi_segment_done_fn_t *done,
 361                           struct ahash_request *hash)
 362 {
 363         __iscsi_segment_init(segment, size, done, hash);
 364         segment->data = data;
 365         segment->size = size;
 366 }
 367 EXPORT_SYMBOL_GPL(iscsi_segment_init_linear);
 368
 369 inline int
 370 iscsi_segment_seek_sg(struct iscsi_segment *segment,
 371                       struct scatterlist *sg_list, unsigned int sg_count,
 372                       unsigned int offset, size_t size,
 373                       iscsi_segment_done_fn_t *done,
 374                       struct ahash_request *hash)
 375 {
 376         struct scatterlist *sg;
 377         unsigned int i;
 378
 379         __iscsi_segment_init(segment, size, done, hash);
 380         for_each_sg(sg_list, sg, sg_count, i) {
 381                 if (offset < sg->length) {
 382                         iscsi_tcp_segment_init_sg(segment, sg, offset);
 383                         return 0;
 384                 }
 385                 offset -= sg->length;
 386         }
 387
 388         return ISCSI_ERR_DATA_OFFSET;
 389 }
 390 EXPORT_SYMBOL_GPL(iscsi_segment_seek_sg);
 391
 392 /**
 393  * iscsi_tcp_hdr_recv_prep - prep segment for hdr reception
 394  * @tcp_conn: iscsi connection to prep for
 395  *
 396  * This function always passes NULL for the hash argument, because when this
 397  * function is called we do not yet know the final size of the header and want
 398  * to delay the digest processing until we know that.
 399  */
 400 void iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn)
 401 {
 402         ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
 403                       "(%s)\n", tcp_conn->iscsi_conn->hdrdgst_en ?
 404                       "digest enabled" : "digest disabled");
 405         iscsi_segment_init_linear(&tcp_conn->in.segment,
 406                                 tcp_conn->in.hdr_buf, sizeof(struct iscsi_hdr),
 407                                 iscsi_tcp_hdr_recv_done, NULL);
 408 }
 409 EXPORT_SYMBOL_GPL(iscsi_tcp_hdr_recv_prep);
 410
 411 /*
 412  * Handle incoming reply to any other type of command
 413  */
 414 static int
 415 iscsi_tcp_data_recv_done(struct iscsi_tcp_conn *tcp_conn,
 416                          struct iscsi_segment *segment)
 417 {
 418         struct iscsi_conn *conn = tcp_conn->iscsi_conn;
 419         int rc = 0;
 420
 421         if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
 422                 return ISCSI_ERR_DATA_DGST;
 423
 424         rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr,
 425                         conn->data, tcp_conn->in.datalen);
 426         if (rc)
 427                 return rc;
 428
 429         iscsi_tcp_hdr_recv_prep(tcp_conn);
 430         return 0;
 431 }
 432
 433 static void
 434 iscsi_tcp_data_recv_prep(struct iscsi_tcp_conn *tcp_conn)
 435 {
 436         struct iscsi_conn *conn = tcp_conn->iscsi_conn;
 437         struct ahash_request *rx_hash = NULL;
 438
 439         if (conn->datadgst_en &&
 440             !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
 441                 rx_hash = tcp_conn->rx_hash;
 442
 443         iscsi_segment_init_linear(&tcp_conn->in.segment,
 444                                 conn->data, tcp_conn->in.datalen,
 445                                 iscsi_tcp_data_recv_done, rx_hash);
 446 }
 447
 448 /**
 449  * iscsi_tcp_cleanup_task - free tcp_task resources
 450  * @task: iscsi task
 451  *
 452  * must be called with session back_lock
 453  */
 454 void iscsi_tcp_cleanup_task(struct iscsi_task *task)
 455 {
 456         struct iscsi_tcp_task *tcp_task = task->dd_data;
 457         struct iscsi_r2t_info *r2t;
 458
 459         /* nothing to do for mgmt */
 460         if (!task->sc)
 461                 return;
 462
 463         spin_lock_bh(&tcp_task->queue2pool);
 464         /* flush task's r2t queues */
 465         while (kfifo_out(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*))) {
 466                 kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
 467                             sizeof(void*));
 468                 ISCSI_DBG_TCP(task->conn, "pending r2t dropped\n");
 469         }
 470
 471         r2t = tcp_task->r2t;
 472         if (r2t != NULL) {
 473                 kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
 474                             sizeof(void*));
 475                 tcp_task->r2t = NULL;
 476         }
 477         spin_unlock_bh(&tcp_task->queue2pool);
 478 }
 479 EXPORT_SYMBOL_GPL(iscsi_tcp_cleanup_task);
 480
 481 /**
 482  * iscsi_tcp_data_in - SCSI Data-In Response processing
 483  * @conn: iscsi connection
 484  * @task: scsi command task
 485  */
 486 static int iscsi_tcp_data_in(struct iscsi_conn *conn, struct iscsi_task *task)
 487 {
 488         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 489         struct iscsi_tcp_task *tcp_task = task->dd_data;
 490         struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)tcp_conn->in.hdr;
 491         int datasn = be32_to_cpu(rhdr->datasn);
 492         unsigned total_in_length = task->sc->sdb.length;
 493
 494         /*
 495          * lib iscsi will update this in the completion handling if there
 496          * is status.
 497          */
 498         if (!(rhdr->flags & ISCSI_FLAG_DATA_STATUS))
 499                 iscsi_update_cmdsn(conn->session, (struct iscsi_nopin*)rhdr);
 500
 501         if (tcp_conn->in.datalen == 0)
 502                 return 0;
 503
 504         if (tcp_task->exp_datasn != datasn) {
 505                 ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->datasn(%d)"
 506                               "\n", tcp_task->exp_datasn, datasn);
 507                 return ISCSI_ERR_DATASN;
 508         }
 509
 510         tcp_task->exp_datasn++;
 511
 512         tcp_task->data_offset = be32_to_cpu(rhdr->offset);
 513         if (tcp_task->data_offset + tcp_conn->in.datalen > total_in_length) {
 514                 ISCSI_DBG_TCP(conn, "data_offset(%d) + data_len(%d) > "
 515                               "total_length_in(%d)\n", tcp_task->data_offset,
 516                               tcp_conn->in.datalen, total_in_length);
 517                 return ISCSI_ERR_DATA_OFFSET;
 518         }
 519
 520         conn->datain_pdus_cnt++;
 521         return 0;
 522 }
 523
 524 /**
 525  * iscsi_tcp_r2t_rsp - iSCSI R2T Response processing
 526  * @conn: iscsi connection
 527  * @task: scsi command task
 528  */
 529 static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
 530 {
 531         struct iscsi_session *session = conn->session;
 532         struct iscsi_tcp_task *tcp_task = task->dd_data;
 533         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 534         struct iscsi_r2t_rsp *rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr;
 535         struct iscsi_r2t_info *r2t;
 536         int r2tsn = be32_to_cpu(rhdr->r2tsn);
 537         u32 data_length;
 538         u32 data_offset;
 539         int rc;
 540
 541         if (tcp_conn->in.datalen) {
 542                 iscsi_conn_printk(KERN_ERR, conn,
 543                                   "invalid R2t with datalen %d\n",
 544                                   tcp_conn->in.datalen);
 545                 return ISCSI_ERR_DATALEN;
 546         }
 547
 548         if (tcp_task->exp_datasn != r2tsn){
 549                 ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->r2tsn(%d)\n",
 550                               tcp_task->exp_datasn, r2tsn);
 551                 return ISCSI_ERR_R2TSN;
 552         }
 553
 554         /* fill-in new R2T associated with the task */
 555         iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr);
 556
 557         if (!task->sc || session->state != ISCSI_STATE_LOGGED_IN) {
 558                 iscsi_conn_printk(KERN_INFO, conn,
 559                                   "dropping R2T itt %d in recovery.\n",
 560                                   task->itt);
 561                 return 0;
 562         }
 563
 564         data_length = be32_to_cpu(rhdr->data_length);
 565         if (data_length == 0) {
 566                 iscsi_conn_printk(KERN_ERR, conn,
 567                                   "invalid R2T with zero data len\n");
 568                 return ISCSI_ERR_DATALEN;
 569         }
 570
 571         if (data_length > session->max_burst)
 572                 ISCSI_DBG_TCP(conn, "invalid R2T with data len %u and max "
 573                               "burst %u. Attempting to execute request.\n",
 574                               data_length, session->max_burst);
 575
 576         data_offset = be32_to_cpu(rhdr->data_offset);
 577         if (data_offset + data_length > task->sc->sdb.length) {
 578                 iscsi_conn_printk(KERN_ERR, conn,
 579                                   "invalid R2T with data len %u at offset %u "
 580                                   "and total length %d\n", data_length,
 581                                   data_offset, task->sc->sdb.length);
 582                 return ISCSI_ERR_DATALEN;
 583         }
 584
 585         spin_lock(&tcp_task->pool2queue);
 586         rc = kfifo_out(&tcp_task->r2tpool.queue, (void *)&r2t, sizeof(void *));
 587         if (!rc) {
 588                 iscsi_conn_printk(KERN_ERR, conn, "Could not allocate R2T. "
 589                                   "Target has sent more R2Ts than it "
 590                                   "negotiated for or driver has leaked.\n");
 591                 spin_unlock(&tcp_task->pool2queue);
 592                 return ISCSI_ERR_PROTO;
 593         }
 594
 595         r2t->exp_statsn = rhdr->statsn;
 596         r2t->data_length = data_length;
 597         r2t->data_offset = data_offset;
 598
 599         r2t->ttt = rhdr->ttt; /* no flip */
 600         r2t->datasn = 0;
 601         r2t->sent = 0;
 602
 603         tcp_task->exp_datasn = r2tsn + 1;
 604         kfifo_in(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*));
 605         conn->r2t_pdus_cnt++;
 606         spin_unlock(&tcp_task->pool2queue);
 607
 608         iscsi_requeue_task(task);
 609         return 0;
 610 }
 611
 612 /*
 613  * Handle incoming reply to DataIn command
 614  */
 615 static int
 616 iscsi_tcp_process_data_in(struct iscsi_tcp_conn *tcp_conn,
 617                           struct iscsi_segment *segment)
 618 {
 619         struct iscsi_conn *conn = tcp_conn->iscsi_conn;
 620         struct iscsi_hdr *hdr = tcp_conn->in.hdr;
 621         int rc;
 622
 623         if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
 624                 return ISCSI_ERR_DATA_DGST;
 625
 626         /* check for non-exceptional status */
 627         if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
 628                 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, NULL, 0);
 629                 if (rc)
 630                         return rc;
 631         }
 632
 633         iscsi_tcp_hdr_recv_prep(tcp_conn);
 634         return 0;
 635 }
 636
 637 /**
 638  * iscsi_tcp_hdr_dissect - process PDU header
 639  * @conn: iSCSI connection
 640  * @hdr: PDU header
 641  *
 642  * This function analyzes the header of the PDU received,
 643  * and performs several sanity checks. If the PDU is accompanied
 644  * by data, the receive buffer is set up to copy the incoming data
 645  * to the correct location.
 646  */
 647 static int
 648 iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
 649 {
 650         int rc = 0, opcode, ahslen;
 651         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 652         struct iscsi_task *task;
 653
 654         /* verify PDU length */
 655         tcp_conn->in.datalen = ntoh24(hdr->dlength);
 656         if (tcp_conn->in.datalen > conn->max_recv_dlength) {
 657                 iscsi_conn_printk(KERN_ERR, conn,
 658                                   "iscsi_tcp: datalen %d > %d\n",
 659                                   tcp_conn->in.datalen, conn->max_recv_dlength);
 660                 return ISCSI_ERR_DATALEN;
 661         }
 662
 663         /* Additional header segments. So far, we don't
 664          * process additional headers.
 665          */
 666         ahslen = hdr->hlength << 2;
 667
 668         opcode = hdr->opcode & ISCSI_OPCODE_MASK;
 669         /* verify itt (itt encoding: age+cid+itt) */
 670         rc = iscsi_verify_itt(conn, hdr->itt);
 671         if (rc)
 672                 return rc;
 673
 674         ISCSI_DBG_TCP(conn, "opcode 0x%x ahslen %d datalen %d\n",
 675                       opcode, ahslen, tcp_conn->in.datalen);
 676
 677         switch(opcode) {
 678         case ISCSI_OP_SCSI_DATA_IN:
 679                 spin_lock(&conn->session->back_lock);
 680                 task = iscsi_itt_to_ctask(conn, hdr->itt);
 681                 if (!task)
 682                         rc = ISCSI_ERR_BAD_ITT;
 683                 else
 684                         rc = iscsi_tcp_data_in(conn, task);
 685                 if (rc) {
 686                         spin_unlock(&conn->session->back_lock);
 687                         break;
 688                 }
 689
 690                 if (tcp_conn->in.datalen) {
 691                         struct iscsi_tcp_task *tcp_task = task->dd_data;
 692                         struct ahash_request *rx_hash = NULL;
 693                         struct scsi_data_buffer *sdb = &task->sc->sdb;
 694
 695                         /*
 696                          * Setup copy of Data-In into the struct scsi_cmnd
 697                          * Scatterlist case:
 698                          * We set up the iscsi_segment to point to the next
 699                          * scatterlist entry to copy to. As we go along,
 700                          * we move on to the next scatterlist entry and
 701                          * update the digest per-entry.
 702                          */
 703                         if (conn->datadgst_en &&
 704                             !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
 705                                 rx_hash = tcp_conn->rx_hash;
 706
 707                         ISCSI_DBG_TCP(conn, "iscsi_tcp_begin_data_in( "
 708                                      "offset=%d, datalen=%d)\n",
 709                                       tcp_task->data_offset,
 710                                       tcp_conn->in.datalen);
 711                         task->last_xfer = jiffies;
 712                         rc = iscsi_segment_seek_sg(&tcp_conn->in.segment,
 713                                                    sdb->table.sgl,
 714                                                    sdb->table.nents,
 715                                                    tcp_task->data_offset,
 716                                                    tcp_conn->in.datalen,
 717                                                    iscsi_tcp_process_data_in,
 718                                                    rx_hash);
 719                         spin_unlock(&conn->session->back_lock);
 720                         return rc;
 721                 }
 722                 rc = __iscsi_complete_pdu(conn, hdr, NULL, 0);
 723                 spin_unlock(&conn->session->back_lock);
 724                 break;
 725         case ISCSI_OP_SCSI_CMD_RSP:
 726                 if (tcp_conn->in.datalen) {
 727                         iscsi_tcp_data_recv_prep(tcp_conn);
 728                         return 0;
 729                 }
 730                 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
 731                 break;
 732         case ISCSI_OP_R2T:
 733                 spin_lock(&conn->session->back_lock);
 734                 task = iscsi_itt_to_ctask(conn, hdr->itt);
 735                 spin_unlock(&conn->session->back_lock);
 736                 if (!task)
 737                         rc = ISCSI_ERR_BAD_ITT;
 738                 else if (ahslen)
 739                         rc = ISCSI_ERR_AHSLEN;
 740                 else if (task->sc->sc_data_direction == DMA_TO_DEVICE) {
 741                         task->last_xfer = jiffies;
 742                         spin_lock(&conn->session->frwd_lock);
 743                         rc = iscsi_tcp_r2t_rsp(conn, task);
 744                         spin_unlock(&conn->session->frwd_lock);
 745                 } else
 746                         rc = ISCSI_ERR_PROTO;
 747                 break;
 748         case ISCSI_OP_LOGIN_RSP:
 749         case ISCSI_OP_TEXT_RSP:
 750         case ISCSI_OP_REJECT:
 751         case ISCSI_OP_ASYNC_EVENT:
 752                 /*
 753                  * It is possible that we could get a PDU with a buffer larger
 754                  * than 8K, but there are no targets that currently do this.
 755                  * For now we fail until we find a vendor that needs it
 756                  */
 757                 if (ISCSI_DEF_MAX_RECV_SEG_LEN < tcp_conn->in.datalen) {
 758                         iscsi_conn_printk(KERN_ERR, conn,
 759                                           "iscsi_tcp: received buffer of "
 760                                           "len %u but conn buffer is only %u "
 761                                           "(opcode %0x)\n",
 762                                           tcp_conn->in.datalen,
 763                                           ISCSI_DEF_MAX_RECV_SEG_LEN, opcode);
 764                         rc = ISCSI_ERR_PROTO;
 765                         break;
 766                 }
 767
 768                 /* If there's data coming in with the response,
 769                  * receive it to the connection's buffer.
 770                  */
 771                 if (tcp_conn->in.datalen) {
 772                         iscsi_tcp_data_recv_prep(tcp_conn);
 773                         return 0;
 774                 }
 775                 fallthrough;
 776         case ISCSI_OP_LOGOUT_RSP:
 777         case ISCSI_OP_NOOP_IN:
 778         case ISCSI_OP_SCSI_TMFUNC_RSP:
 779                 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
 780                 break;
 781         default:
 782                 rc = ISCSI_ERR_BAD_OPCODE;
 783                 break;
 784         }
 785
 786         if (rc == 0) {
 787                 /* Anything that comes with data should have
 788                  * been handled above. */
 789                 if (tcp_conn->in.datalen)
 790                         return ISCSI_ERR_PROTO;
 791                 iscsi_tcp_hdr_recv_prep(tcp_conn);
 792         }
 793
 794         return rc;
 795 }
 796
 797 /**
 798  * iscsi_tcp_hdr_recv_done - process PDU header
 799  * @tcp_conn: iSCSI TCP connection
 800  * @segment: the buffer segment being processed
 801  *
 802  * This is the callback invoked when the PDU header has
 803  * been received. If the header is followed by additional
 804  * header segments, we go back for more data.
 805  */
 806 static int
 807 iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
 808                         struct iscsi_segment *segment)
 809 {
 810         struct iscsi_conn *conn = tcp_conn->iscsi_conn;
 811         struct iscsi_hdr *hdr;
 812
 813         /* Check if there are additional header segments
 814          * *prior* to computing the digest, because we
 815          * may need to go back to the caller for more.
 816          */
 817         hdr = (struct iscsi_hdr *) tcp_conn->in.hdr_buf;
 818         if (segment->copied == sizeof(struct iscsi_hdr) && hdr->hlength) {
 819                 /* Bump the header length - the caller will
 820                  * just loop around and get the AHS for us, and
 821                  * call again. */
 822                 unsigned int ahslen = hdr->hlength << 2;
 823
 824                 /* Make sure we don't overflow */
 825                 if (sizeof(*hdr) + ahslen > sizeof(tcp_conn->in.hdr_buf))
 826                         return ISCSI_ERR_AHSLEN;
 827
 828                 segment->total_size += ahslen;
 829                 segment->size += ahslen;
 830                 return 0;
 831         }
 832
 833         /* We're done processing the header. See if we're doing
 834          * header digests; if so, set up the recv_digest buffer
 835          * and go back for more. */
 836         if (conn->hdrdgst_en &&
 837             !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD)) {
 838                 if (segment->digest_len == 0) {
 839                         /*
 840                          * Even if we offload the digest processing we
 841                          * splice it in so we can increment the skb/segment
 842                          * counters in preparation for the data segment.
 843                          */
 844                         iscsi_tcp_segment_splice_digest(segment,
 845                                                         segment->recv_digest);
 846                         return 0;
 847                 }
 848
 849                 iscsi_tcp_dgst_header(tcp_conn->rx_hash, hdr,
 850                                       segment->total_copied - ISCSI_DIGEST_SIZE,
 851                                       segment->digest);
 852
 853                 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
 854                         return ISCSI_ERR_HDR_DGST;
 855         }
 856
 857         tcp_conn->in.hdr = hdr;
 858         return iscsi_tcp_hdr_dissect(conn, hdr);
 859 }
 860
 861 /**
 862  * iscsi_tcp_recv_segment_is_hdr - tests if we are reading in a header
 863  * @tcp_conn: iscsi tcp conn
 864  *
 865  * returns non zero if we are currently processing or setup to process
 866  * a header.
 867  */
 868 inline int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn)
 869 {
 870         return tcp_conn->in.segment.done == iscsi_tcp_hdr_recv_done;
 871 }
 872 EXPORT_SYMBOL_GPL(iscsi_tcp_recv_segment_is_hdr);
 873
 874 /**
 875  * iscsi_tcp_recv_skb - Process skb
 876  * @conn: iscsi connection
 877  * @skb: network buffer with header and/or data segment
 878  * @offset: offset in skb
 879  * @offloaded: bool indicating if transfer was offloaded
 880  * @status: iscsi TCP status result
 881  *
 882  * Will return status of transfer in @status. And will return
 883  * number of bytes copied.
 884  */
 885 int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
 886                        unsigned int offset, bool offloaded, int *status)
 887 {
 888         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 889         struct iscsi_segment *segment = &tcp_conn->in.segment;
 890         struct skb_seq_state seq;
 891         unsigned int consumed = 0;
 892         int rc = 0;
 893
 894         ISCSI_DBG_TCP(conn, "in %d bytes\n", skb->len - offset);
 895         /*
 896          * Update for each skb instead of pdu, because over slow networks a
 897          * data_in's data could take a while to read in. We also want to
 898          * account for r2ts.
 899          */
 900         conn->last_recv = jiffies;
 901
 902         if (unlikely(conn->suspend_rx)) {
 903                 ISCSI_DBG_TCP(conn, "Rx suspended!\n");
 904                 *status = ISCSI_TCP_SUSPENDED;
 905                 return 0;
 906         }
 907
 908         if (offloaded) {
 909                 segment->total_copied = segment->total_size;
 910                 goto segment_done;
 911         }
 912
 913         skb_prepare_seq_read(skb, offset, skb->len, &seq);
 914         while (1) {
 915                 unsigned int avail;
 916                 const u8 *ptr;
 917
 918                 avail = skb_seq_read(consumed, &ptr, &seq);
 919                 if (avail == 0) {
 920                         ISCSI_DBG_TCP(conn, "no more data avail. Consumed %d\n",
 921                                       consumed);
 922                         *status = ISCSI_TCP_SKB_DONE;
 923                         goto skb_done;
 924                 }
 925                 BUG_ON(segment->copied >= segment->size);
 926
 927                 ISCSI_DBG_TCP(conn, "skb %p ptr=%p avail=%u\n", skb, ptr,
 928                               avail);
 929                 rc = iscsi_tcp_segment_recv(tcp_conn, segment, ptr, avail);
 930                 BUG_ON(rc == 0);
 931                 consumed += rc;
 932
 933                 if (segment->total_copied >= segment->total_size) {
 934                         skb_abort_seq_read(&seq);
 935                         goto segment_done;
 936                 }
 937         }
 938
 939 segment_done:
 940         *status = ISCSI_TCP_SEGMENT_DONE;
 941         ISCSI_DBG_TCP(conn, "segment done\n");
 942         rc = segment->done(tcp_conn, segment);
 943         if (rc != 0) {
 944                 *status = ISCSI_TCP_CONN_ERR;
 945                 ISCSI_DBG_TCP(conn, "Error receiving PDU, errno=%d\n", rc);
 946                 iscsi_conn_failure(conn, rc);
 947                 return 0;
 948         }
 949         /* The done() functions sets up the next segment. */
 950
 951 skb_done:
 952         conn->rxdata_octets += consumed;
 953         return consumed;
 954 }
 955 EXPORT_SYMBOL_GPL(iscsi_tcp_recv_skb);
 956
 957 /**
 958  * iscsi_tcp_task_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
 959  * @task: scsi command task
 960  */
 961 int iscsi_tcp_task_init(struct iscsi_task *task)
 962 {
 963         struct iscsi_tcp_task *tcp_task = task->dd_data;
 964         struct iscsi_conn *conn = task->conn;
 965         struct scsi_cmnd *sc = task->sc;
 966         int err;
 967
 968         if (!sc) {
 969                 /*
 970                  * mgmt tasks do not have a scatterlist since they come
 971                  * in from the iscsi interface.
 972                  */
 973                 ISCSI_DBG_TCP(conn, "mtask deq [itt 0x%x]\n", task->itt);
 974
 975                 return conn->session->tt->init_pdu(task, 0, task->data_count);
 976         }
 977
 978         BUG_ON(kfifo_len(&tcp_task->r2tqueue));
 979         tcp_task->exp_datasn = 0;
 980
 981         /* Prepare PDU, optionally w/ immediate data */
 982         ISCSI_DBG_TCP(conn, "task deq [itt 0x%x imm %d unsol %d]\n",
 983                       task->itt, task->imm_count, task->unsol_r2t.data_length);
 984
 985         err = conn->session->tt->init_pdu(task, 0, task->imm_count);
 986         if (err)
 987                 return err;
 988         task->imm_count = 0;
 989         return 0;
 990 }
 991 EXPORT_SYMBOL_GPL(iscsi_tcp_task_init);
 992
 993 static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
 994 {
 995         struct iscsi_tcp_task *tcp_task = task->dd_data;
 996         struct iscsi_r2t_info *r2t = NULL;
 997
 998         if (iscsi_task_has_unsol_data(task))
 999                 r2t = &task->unsol_r2t;
1000         else {
1001                 spin_lock_bh(&tcp_task->queue2pool);
1002                 if (tcp_task->r2t) {
1003                         r2t = tcp_task->r2t;
1004                         /* Continue with this R2T? */
1005                         if (r2t->data_length <= r2t->sent) {
1006                                 ISCSI_DBG_TCP(task->conn,
1007                                               "  done with r2t %p\n", r2t);
1008                                 kfifo_in(&tcp_task->r2tpool.queue,
1009                                             (void *)&tcp_task->r2t,
1010                                             sizeof(void *));
1011                                 tcp_task->r2t = r2t = NULL;
1012                         }
1013                 }
1014
1015                 if (r2t == NULL) {
1016                         if (kfifo_out(&tcp_task->r2tqueue,
1017                             (void *)&tcp_task->r2t, sizeof(void *)) !=
1018                             sizeof(void *))
1019                                 r2t = NULL;
1020                         else
1021                                 r2t = tcp_task->r2t;
1022                 }
1023                 spin_unlock_bh(&tcp_task->queue2pool);
1024         }
1025
1026         return r2t;
1027 }
1028
1029 /**
1030  * iscsi_tcp_task_xmit - xmit normal PDU task
1031  * @task: iscsi command task
1032  *
1033  * We're expected to return 0 when everything was transmitted successfully,
1034  * -EAGAIN if there's still data in the queue, or != 0 for any other kind
1035  * of error.
1036  */
1037 int iscsi_tcp_task_xmit(struct iscsi_task *task)
1038 {
1039         struct iscsi_conn *conn = task->conn;
1040         struct iscsi_session *session = conn->session;
1041         struct iscsi_r2t_info *r2t;
1042         int rc = 0;
1043
1044 flush:
1045         /* Flush any pending data first. */
1046         rc = session->tt->xmit_pdu(task);
1047         if (rc < 0)
1048                 return rc;
1049
1050         /* mgmt command */
1051         if (!task->sc) {
1052                 if (task->hdr->itt == RESERVED_ITT)
1053                         iscsi_put_task(task);
1054                 return 0;
1055         }
1056
1057         /* Are we done already? */
1058         if (task->sc->sc_data_direction != DMA_TO_DEVICE)
1059                 return 0;
1060
1061         r2t = iscsi_tcp_get_curr_r2t(task);
1062         if (r2t == NULL) {
1063                 /* Waiting for more R2Ts to arrive. */
1064                 ISCSI_DBG_TCP(conn, "no R2Ts yet\n");
1065                 return 0;
1066         }
1067
1068         rc = conn->session->tt->alloc_pdu(task, ISCSI_OP_SCSI_DATA_OUT);
1069         if (rc)
1070                 return rc;
1071         iscsi_prep_data_out_pdu(task, r2t, (struct iscsi_data *) task->hdr);
1072
1073         ISCSI_DBG_TCP(conn, "sol dout %p [dsn %d itt 0x%x doff %d dlen %d]\n",
1074                       r2t, r2t->datasn - 1, task->hdr->itt,
1075                       r2t->data_offset + r2t->sent, r2t->data_count);
1076
1077         rc = conn->session->tt->init_pdu(task, r2t->data_offset + r2t->sent,
1078                                          r2t->data_count);
1079         if (rc) {
1080                 iscsi_conn_failure(conn, ISCSI_ERR_XMIT_FAILED);
1081                 return rc;
1082         }
1083
1084         r2t->sent += r2t->data_count;
1085         goto flush;
1086 }
1087 EXPORT_SYMBOL_GPL(iscsi_tcp_task_xmit);
1088
1089 struct iscsi_cls_conn *
1090 iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
1091                       uint32_t conn_idx)
1092
1093 {
1094         struct iscsi_conn *conn;
1095         struct iscsi_cls_conn *cls_conn;
1096         struct iscsi_tcp_conn *tcp_conn;
1097
1098         cls_conn = iscsi_conn_setup(cls_session,
1099                                     sizeof(*tcp_conn) + dd_data_size, conn_idx);
1100         if (!cls_conn)
1101                 return NULL;
1102         conn = cls_conn->dd_data;
1103         /*
1104          * due to strange issues with iser these are not set
1105          * in iscsi_conn_setup
1106          */
1107         conn->max_recv_dlength = ISCSI_DEF_MAX_RECV_SEG_LEN;
1108
1109         tcp_conn = conn->dd_data;
1110         tcp_conn->iscsi_conn = conn;
1111         tcp_conn->dd_data = conn->dd_data + sizeof(*tcp_conn);
1112         return cls_conn;
1113 }
1114 EXPORT_SYMBOL_GPL(iscsi_tcp_conn_setup);
1115
1116 void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn)
1117 {
1118         iscsi_conn_teardown(cls_conn);
1119 }
1120 EXPORT_SYMBOL_GPL(iscsi_tcp_conn_teardown);
1121
1122 int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session)
1123 {
1124         int i;
1125         int cmd_i;
1126
1127         /*
1128          * initialize per-task: R2T pool and xmit queue
1129          */
1130         for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
1131                 struct iscsi_task *task = session->cmds[cmd_i];
1132                 struct iscsi_tcp_task *tcp_task = task->dd_data;
1133
1134                 /*
1135                  * pre-allocated x2 as much r2ts to handle race when
1136                  * target acks DataOut faster than we data_xmit() queues
1137                  * could replenish r2tqueue.
1138                  */
1139
1140                 /* R2T pool */
1141                 if (iscsi_pool_init(&tcp_task->r2tpool,
1142                                     session->max_r2t * 2, NULL,
1143                                     sizeof(struct iscsi_r2t_info))) {
1144                         goto r2t_alloc_fail;
1145                 }
1146
1147                 /* R2T xmit queue */
1148                 if (kfifo_alloc(&tcp_task->r2tqueue,
1149                       session->max_r2t * 4 * sizeof(void*), GFP_KERNEL)) {
1150                         iscsi_pool_free(&tcp_task->r2tpool);
1151                         goto r2t_alloc_fail;
1152                 }
1153                 spin_lock_init(&tcp_task->pool2queue);
1154                 spin_lock_init(&tcp_task->queue2pool);
1155         }
1156
1157         return 0;
1158
1159 r2t_alloc_fail:
1160         for (i = 0; i < cmd_i; i++) {
1161                 struct iscsi_task *task = session->cmds[i];
1162                 struct iscsi_tcp_task *tcp_task = task->dd_data;
1163
1164                 kfifo_free(&tcp_task->r2tqueue);
1165                 iscsi_pool_free(&tcp_task->r2tpool);
1166         }
1167         return -ENOMEM;
1168 }
1169 EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_alloc);
1170
1171 void iscsi_tcp_r2tpool_free(struct iscsi_session *session)
1172 {
1173         int i;
1174
1175         for (i = 0; i < session->cmds_max; i++) {
1176                 struct iscsi_task *task = session->cmds[i];
1177                 struct iscsi_tcp_task *tcp_task = task->dd_data;
1178
1179                 kfifo_free(&tcp_task->r2tqueue);
1180                 iscsi_pool_free(&tcp_task->r2tpool);
1181         }
1182 }
1183 EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_free);
1184
1185 int iscsi_tcp_set_max_r2t(struct iscsi_conn *conn, char *buf)
1186 {
1187         struct iscsi_session *session = conn->session;
1188         unsigned short r2ts = 0;
1189
1190         sscanf(buf, "%hu", &r2ts);
1191         if (session->max_r2t == r2ts)
1192                 return 0;
1193
1194         if (!r2ts || !is_power_of_2(r2ts))
1195                 return -EINVAL;
1196
1197         session->max_r2t = r2ts;
1198         iscsi_tcp_r2tpool_free(session);
1199         return iscsi_tcp_r2tpool_alloc(session);
1200 }
1201 EXPORT_SYMBOL_GPL(iscsi_tcp_set_max_r2t);
1202
1203 void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
1204                               struct iscsi_stats *stats)
1205 {
1206         struct iscsi_conn *conn = cls_conn->dd_data;
1207
1208         stats->txdata_octets = conn->txdata_octets;
1209         stats->rxdata_octets = conn->rxdata_octets;
1210         stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
1211         stats->dataout_pdus = conn->dataout_pdus_cnt;
1212         stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
1213         stats->datain_pdus = conn->datain_pdus_cnt;
1214         stats->r2t_pdus = conn->r2t_pdus_cnt;
1215         stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
1216         stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
1217 }
1218 EXPORT_SYMBOL_GPL(iscsi_tcp_conn_get_stats);