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 <crypto/hash.h>
  30 #include <linux/types.h>
  31 #include <linux/list.h>
  32 #include <linux/inet.h>
  33 #include <linux/slab.h>
  34 #include <linux/file.h>
  35 #include <linux/blkdev.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                 ahash_request_set_crypt(segment->hash, &sg, NULL, copied);
 218                 crypto_ahash_update(segment->hash);
 219         }
 220
 221         segment->copied += copied;
 222         if (segment->copied < segment->size) {
 223                 iscsi_tcp_segment_map(segment, recv);
 224                 return 0;
 225         }
 226
 227         segment->total_copied += segment->copied;
 228         segment->copied = 0;
 229         segment->size = 0;
 230
 231         /* Unmap the current scatterlist page, if there is one. */
 232         iscsi_tcp_segment_unmap(segment);
 233
 234         /* Do we have more scatterlist entries? */
 235         ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "total copied %u total size %u\n",
 236                       segment->total_copied, segment->total_size);
 237         if (segment->total_copied < segment->total_size) {
 238                 /* Proceed to the next entry in the scatterlist. */
 239                 iscsi_tcp_segment_init_sg(segment, sg_next(segment->sg),
 240                                           0);
 241                 iscsi_tcp_segment_map(segment, recv);
 242                 BUG_ON(segment->size == 0);
 243                 return 0;
 244         }
 245
 246         /* Do we need to handle padding? */
 247         if (!(tcp_conn->iscsi_conn->session->tt->caps & CAP_PADDING_OFFLOAD)) {
 248                 pad = iscsi_padding(segment->total_copied);
 249                 if (pad != 0) {
 250                         ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
 251                                       "consume %d pad bytes\n", pad);
 252                         segment->total_size += pad;
 253                         segment->size = pad;
 254                         segment->data = segment->padbuf;
 255                         return 0;
 256                 }
 257         }
 258
 259         /*
 260          * Set us up for transferring the data digest. hdr digest
 261          * is completely handled in hdr done function.
 262          */
 263         if (segment->hash) {
 264                 ahash_request_set_crypt(segment->hash, NULL,
 265                                         segment->digest, 0);
 266                 crypto_ahash_final(segment->hash);
 267                 iscsi_tcp_segment_splice_digest(segment,
 268                                  recv ? segment->recv_digest : segment->digest);
 269                 return 0;
 270         }
 271
 272         return 1;
 273 }
 274 EXPORT_SYMBOL_GPL(iscsi_tcp_segment_done);
 275
 276 /**
 277  * iscsi_tcp_segment_recv - copy data to segment
 278  * @tcp_conn: the iSCSI TCP connection
 279  * @segment: the buffer to copy to
 280  * @ptr: data pointer
 281  * @len: amount of data available
 282  *
 283  * This function copies up to @len bytes to the
 284  * given buffer, and returns the number of bytes
 285  * consumed, which can actually be less than @len.
 286  *
 287  * If hash digest is enabled, the function will update the
 288  * hash while copying.
 289  * Combining these two operations doesn't buy us a lot (yet),
 290  * but in the future we could implement combined copy+crc,
 291  * just way we do for network layer checksums.
 292  */
 293 static int
 294 iscsi_tcp_segment_recv(struct iscsi_tcp_conn *tcp_conn,
 295                        struct iscsi_segment *segment, const void *ptr,
 296                        unsigned int len)
 297 {
 298         unsigned int copy = 0, copied = 0;
 299
 300         while (!iscsi_tcp_segment_done(tcp_conn, segment, 1, copy)) {
 301                 if (copied == len) {
 302                         ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
 303                                       "copied %d bytes\n", len);
 304                         break;
 305                 }
 306
 307                 copy = min(len - copied, segment->size - segment->copied);
 308                 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "copying %d\n", copy);
 309                 memcpy(segment->data + segment->copied, ptr + copied, copy);
 310                 copied += copy;
 311         }
 312         return copied;
 313 }
 314
 315 inline void
 316 iscsi_tcp_dgst_header(struct ahash_request *hash, const void *hdr,
 317                       size_t hdrlen, unsigned char digest[ISCSI_DIGEST_SIZE])
 318 {
 319         struct scatterlist sg;
 320
 321         sg_init_one(&sg, hdr, hdrlen);
 322         ahash_request_set_crypt(hash, &sg, digest, hdrlen);
 323         crypto_ahash_digest(hash);
 324 }
 325 EXPORT_SYMBOL_GPL(iscsi_tcp_dgst_header);
 326
 327 static inline int
 328 iscsi_tcp_dgst_verify(struct iscsi_tcp_conn *tcp_conn,
 329                       struct iscsi_segment *segment)
 330 {
 331         if (!segment->digest_len)
 332                 return 1;
 333
 334         if (memcmp(segment->recv_digest, segment->digest,
 335                    segment->digest_len)) {
 336                 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "digest mismatch\n");
 337                 return 0;
 338         }
 339
 340         return 1;
 341 }
 342
 343 /*
 344  * Helper function to set up segment buffer
 345  */
 346 static inline void
 347 __iscsi_segment_init(struct iscsi_segment *segment, size_t size,
 348                      iscsi_segment_done_fn_t *done, struct ahash_request *hash)
 349 {
 350         memset(segment, 0, sizeof(*segment));
 351         segment->total_size = size;
 352         segment->done = done;
 353
 354         if (hash) {
 355                 segment->hash = hash;
 356                 crypto_ahash_init(hash);
 357         }
 358 }
 359
 360 inline void
 361 iscsi_segment_init_linear(struct iscsi_segment *segment, void *data,
 362                           size_t size, iscsi_segment_done_fn_t *done,
 363                           struct ahash_request *hash)
 364 {
 365         __iscsi_segment_init(segment, size, done, hash);
 366         segment->data = data;
 367         segment->size = size;
 368 }
 369 EXPORT_SYMBOL_GPL(iscsi_segment_init_linear);
 370
 371 inline int
 372 iscsi_segment_seek_sg(struct iscsi_segment *segment,
 373                       struct scatterlist *sg_list, unsigned int sg_count,
 374                       unsigned int offset, size_t size,
 375                       iscsi_segment_done_fn_t *done,
 376                       struct ahash_request *hash)
 377 {
 378         struct scatterlist *sg;
 379         unsigned int i;
 380
 381         __iscsi_segment_init(segment, size, done, hash);
 382         for_each_sg(sg_list, sg, sg_count, i) {
 383                 if (offset < sg->length) {
 384                         iscsi_tcp_segment_init_sg(segment, sg, offset);
 385                         return 0;
 386                 }
 387                 offset -= sg->length;
 388         }
 389
 390         return ISCSI_ERR_DATA_OFFSET;
 391 }
 392 EXPORT_SYMBOL_GPL(iscsi_segment_seek_sg);
 393
 394 /**
 395  * iscsi_tcp_hdr_recv_prep - prep segment for hdr reception
 396  * @tcp_conn: iscsi connection to prep for
 397  *
 398  * This function always passes NULL for the hash argument, because when this
 399  * function is called we do not yet know the final size of the header and want
 400  * to delay the digest processing until we know that.
 401  */
 402 void iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn)
 403 {
 404         ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
 405                       "(%s)\n", tcp_conn->iscsi_conn->hdrdgst_en ?
 406                       "digest enabled" : "digest disabled");
 407         iscsi_segment_init_linear(&tcp_conn->in.segment,
 408                                 tcp_conn->in.hdr_buf, sizeof(struct iscsi_hdr),
 409                                 iscsi_tcp_hdr_recv_done, NULL);
 410 }
 411 EXPORT_SYMBOL_GPL(iscsi_tcp_hdr_recv_prep);
 412
 413 /*
 414  * Handle incoming reply to any other type of command
 415  */
 416 static int
 417 iscsi_tcp_data_recv_done(struct iscsi_tcp_conn *tcp_conn,
 418                          struct iscsi_segment *segment)
 419 {
 420         struct iscsi_conn *conn = tcp_conn->iscsi_conn;
 421         int rc = 0;
 422
 423         if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
 424                 return ISCSI_ERR_DATA_DGST;
 425
 426         rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr,
 427                         conn->data, tcp_conn->in.datalen);
 428         if (rc)
 429                 return rc;
 430
 431         iscsi_tcp_hdr_recv_prep(tcp_conn);
 432         return 0;
 433 }
 434
 435 static void
 436 iscsi_tcp_data_recv_prep(struct iscsi_tcp_conn *tcp_conn)
 437 {
 438         struct iscsi_conn *conn = tcp_conn->iscsi_conn;
 439         struct ahash_request *rx_hash = NULL;
 440
 441         if (conn->datadgst_en &&
 442             !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
 443                 rx_hash = tcp_conn->rx_hash;
 444
 445         iscsi_segment_init_linear(&tcp_conn->in.segment,
 446                                 conn->data, tcp_conn->in.datalen,
 447                                 iscsi_tcp_data_recv_done, rx_hash);
 448 }
 449
 450 /**
 451  * iscsi_tcp_cleanup_task - free tcp_task resources
 452  * @task: iscsi task
 453  *
 454  * must be called with session back_lock
 455  */
 456 void iscsi_tcp_cleanup_task(struct iscsi_task *task)
 457 {
 458         struct iscsi_tcp_task *tcp_task = task->dd_data;
 459         struct iscsi_r2t_info *r2t;
 460
 461         /* nothing to do for mgmt */
 462         if (!task->sc)
 463                 return;
 464
 465         spin_lock_bh(&tcp_task->queue2pool);
 466         /* flush task's r2t queues */
 467         while (kfifo_out(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*))) {
 468                 kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
 469                             sizeof(void*));
 470                 ISCSI_DBG_TCP(task->conn, "pending r2t dropped\n");
 471         }
 472
 473         r2t = tcp_task->r2t;
 474         if (r2t != NULL) {
 475                 kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
 476                             sizeof(void*));
 477                 tcp_task->r2t = NULL;
 478         }
 479         spin_unlock_bh(&tcp_task->queue2pool);
 480 }
 481 EXPORT_SYMBOL_GPL(iscsi_tcp_cleanup_task);
 482
 483 /**
 484  * iscsi_tcp_data_in - SCSI Data-In Response processing
 485  * @conn: iscsi connection
 486  * @task: scsi command task
 487  */
 488 static int iscsi_tcp_data_in(struct iscsi_conn *conn, struct iscsi_task *task)
 489 {
 490         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 491         struct iscsi_tcp_task *tcp_task = task->dd_data;
 492         struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)tcp_conn->in.hdr;
 493         int datasn = be32_to_cpu(rhdr->datasn);
 494         unsigned total_in_length = scsi_in(task->sc)->length;
 495
 496         /*
 497          * lib iscsi will update this in the completion handling if there
 498          * is status.
 499          */
 500         if (!(rhdr->flags & ISCSI_FLAG_DATA_STATUS))
 501                 iscsi_update_cmdsn(conn->session, (struct iscsi_nopin*)rhdr);
 502
 503         if (tcp_conn->in.datalen == 0)
 504                 return 0;
 505
 506         if (tcp_task->exp_datasn != datasn) {
 507                 ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->datasn(%d)"
 508                               "\n", tcp_task->exp_datasn, datasn);
 509                 return ISCSI_ERR_DATASN;
 510         }
 511
 512         tcp_task->exp_datasn++;
 513
 514         tcp_task->data_offset = be32_to_cpu(rhdr->offset);
 515         if (tcp_task->data_offset + tcp_conn->in.datalen > total_in_length) {
 516                 ISCSI_DBG_TCP(conn, "data_offset(%d) + data_len(%d) > "
 517                               "total_length_in(%d)\n", tcp_task->data_offset,
 518                               tcp_conn->in.datalen, total_in_length);
 519                 return ISCSI_ERR_DATA_OFFSET;
 520         }
 521
 522         conn->datain_pdus_cnt++;
 523         return 0;
 524 }
 525
 526 /**
 527  * iscsi_tcp_r2t_rsp - iSCSI R2T Response processing
 528  * @conn: iscsi connection
 529  * @task: scsi command task
 530  */
 531 static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
 532 {
 533         struct iscsi_session *session = conn->session;
 534         struct iscsi_tcp_task *tcp_task = task->dd_data;
 535         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 536         struct iscsi_r2t_rsp *rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr;
 537         struct iscsi_r2t_info *r2t;
 538         int r2tsn = be32_to_cpu(rhdr->r2tsn);
 539         u32 data_length;
 540         u32 data_offset;
 541         int rc;
 542
 543         if (tcp_conn->in.datalen) {
 544                 iscsi_conn_printk(KERN_ERR, conn,
 545                                   "invalid R2t with datalen %d\n",
 546                                   tcp_conn->in.datalen);
 547                 return ISCSI_ERR_DATALEN;
 548         }
 549
 550         if (tcp_task->exp_datasn != r2tsn){
 551                 ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->r2tsn(%d)\n",
 552                               tcp_task->exp_datasn, r2tsn);
 553                 return ISCSI_ERR_R2TSN;
 554         }
 555
 556         /* fill-in new R2T associated with the task */
 557         iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr);
 558
 559         if (!task->sc || session->state != ISCSI_STATE_LOGGED_IN) {
 560                 iscsi_conn_printk(KERN_INFO, conn,
 561                                   "dropping R2T itt %d in recovery.\n",
 562                                   task->itt);
 563                 return 0;
 564         }
 565
 566         data_length = be32_to_cpu(rhdr->data_length);
 567         if (data_length == 0) {
 568                 iscsi_conn_printk(KERN_ERR, conn,
 569                                   "invalid R2T with zero data len\n");
 570                 return ISCSI_ERR_DATALEN;
 571         }
 572
 573         if (data_length > session->max_burst)
 574                 ISCSI_DBG_TCP(conn, "invalid R2T with data len %u and max "
 575                               "burst %u. Attempting to execute request.\n",
 576                               data_length, session->max_burst);
 577
 578         data_offset = be32_to_cpu(rhdr->data_offset);
 579         if (data_offset + data_length > scsi_out(task->sc)->length) {
 580                 iscsi_conn_printk(KERN_ERR, conn,
 581                                   "invalid R2T with data len %u at offset %u "
 582                                   "and total length %d\n", data_length,
 583                                   data_offset, scsi_out(task->sc)->length);
 584                 return ISCSI_ERR_DATALEN;
 585         }
 586
 587         spin_lock(&tcp_task->pool2queue);
 588         rc = kfifo_out(&tcp_task->r2tpool.queue, (void *)&r2t, sizeof(void *));
 589         if (!rc) {
 590                 iscsi_conn_printk(KERN_ERR, conn, "Could not allocate R2T. "
 591                                   "Target has sent more R2Ts than it "
 592                                   "negotiated for or driver has leaked.\n");
 593                 spin_unlock(&tcp_task->pool2queue);
 594                 return ISCSI_ERR_PROTO;
 595         }
 596
 597         r2t->exp_statsn = rhdr->statsn;
 598         r2t->data_length = data_length;
 599         r2t->data_offset = data_offset;
 600
 601         r2t->ttt = rhdr->ttt; /* no flip */
 602         r2t->datasn = 0;
 603         r2t->sent = 0;
 604
 605         tcp_task->exp_datasn = r2tsn + 1;
 606         kfifo_in(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*));
 607         conn->r2t_pdus_cnt++;
 608         spin_unlock(&tcp_task->pool2queue);
 609
 610         iscsi_requeue_task(task);
 611         return 0;
 612 }
 613
 614 /*
 615  * Handle incoming reply to DataIn command
 616  */
 617 static int
 618 iscsi_tcp_process_data_in(struct iscsi_tcp_conn *tcp_conn,
 619                           struct iscsi_segment *segment)
 620 {
 621         struct iscsi_conn *conn = tcp_conn->iscsi_conn;
 622         struct iscsi_hdr *hdr = tcp_conn->in.hdr;
 623         int rc;
 624
 625         if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
 626                 return ISCSI_ERR_DATA_DGST;
 627
 628         /* check for non-exceptional status */
 629         if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
 630                 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, NULL, 0);
 631                 if (rc)
 632                         return rc;
 633         }
 634
 635         iscsi_tcp_hdr_recv_prep(tcp_conn);
 636         return 0;
 637 }
 638
 639 /**
 640  * iscsi_tcp_hdr_dissect - process PDU header
 641  * @conn: iSCSI connection
 642  * @hdr: PDU header
 643  *
 644  * This function analyzes the header of the PDU received,
 645  * and performs several sanity checks. If the PDU is accompanied
 646  * by data, the receive buffer is set up to copy the incoming data
 647  * to the correct location.
 648  */
 649 static int
 650 iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
 651 {
 652         int rc = 0, opcode, ahslen;
 653         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 654         struct iscsi_task *task;
 655
 656         /* verify PDU length */
 657         tcp_conn->in.datalen = ntoh24(hdr->dlength);
 658         if (tcp_conn->in.datalen > conn->max_recv_dlength) {
 659                 iscsi_conn_printk(KERN_ERR, conn,
 660                                   "iscsi_tcp: datalen %d > %d\n",
 661                                   tcp_conn->in.datalen, conn->max_recv_dlength);
 662                 return ISCSI_ERR_DATALEN;
 663         }
 664
 665         /* Additional header segments. So far, we don't
 666          * process additional headers.
 667          */
 668         ahslen = hdr->hlength << 2;
 669
 670         opcode = hdr->opcode & ISCSI_OPCODE_MASK;
 671         /* verify itt (itt encoding: age+cid+itt) */
 672         rc = iscsi_verify_itt(conn, hdr->itt);
 673         if (rc)
 674                 return rc;
 675
 676         ISCSI_DBG_TCP(conn, "opcode 0x%x ahslen %d datalen %d\n",
 677                       opcode, ahslen, tcp_conn->in.datalen);
 678
 679         switch(opcode) {
 680         case ISCSI_OP_SCSI_DATA_IN:
 681                 spin_lock(&conn->session->back_lock);
 682                 task = iscsi_itt_to_ctask(conn, hdr->itt);
 683                 if (!task)
 684                         rc = ISCSI_ERR_BAD_ITT;
 685                 else
 686                         rc = iscsi_tcp_data_in(conn, task);
 687                 if (rc) {
 688                         spin_unlock(&conn->session->back_lock);
 689                         break;
 690                 }
 691
 692                 if (tcp_conn->in.datalen) {
 693                         struct iscsi_tcp_task *tcp_task = task->dd_data;
 694                         struct ahash_request *rx_hash = NULL;
 695                         struct scsi_data_buffer *sdb = scsi_in(task->sc);
 696
 697                         /*
 698                          * Setup copy of Data-In into the Scsi_Cmnd
 699                          * Scatterlist case:
 700                          * We set up the iscsi_segment to point to the next
 701                          * scatterlist entry to copy to. As we go along,
 702                          * we move on to the next scatterlist entry and
 703                          * update the digest per-entry.
 704                          */
 705                         if (conn->datadgst_en &&
 706                             !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
 707                                 rx_hash = tcp_conn->rx_hash;
 708
 709                         ISCSI_DBG_TCP(conn, "iscsi_tcp_begin_data_in( "
 710                                      "offset=%d, datalen=%d)\n",
 711                                       tcp_task->data_offset,
 712                                       tcp_conn->in.datalen);
 713                         task->last_xfer = jiffies;
 714                         rc = iscsi_segment_seek_sg(&tcp_conn->in.segment,
 715                                                    sdb->table.sgl,
 716                                                    sdb->table.nents,
 717                                                    tcp_task->data_offset,
 718                                                    tcp_conn->in.datalen,
 719                                                    iscsi_tcp_process_data_in,
 720                                                    rx_hash);
 721                         spin_unlock(&conn->session->back_lock);
 722                         return rc;
 723                 }
 724                 rc = __iscsi_complete_pdu(conn, hdr, NULL, 0);
 725                 spin_unlock(&conn->session->back_lock);
 726                 break;
 727         case ISCSI_OP_SCSI_CMD_RSP:
 728                 if (tcp_conn->in.datalen) {
 729                         iscsi_tcp_data_recv_prep(tcp_conn);
 730                         return 0;
 731                 }
 732                 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
 733                 break;
 734         case ISCSI_OP_R2T:
 735                 spin_lock(&conn->session->back_lock);
 736                 task = iscsi_itt_to_ctask(conn, hdr->itt);
 737                 spin_unlock(&conn->session->back_lock);
 738                 if (!task)
 739                         rc = ISCSI_ERR_BAD_ITT;
 740                 else if (ahslen)
 741                         rc = ISCSI_ERR_AHSLEN;
 742                 else if (task->sc->sc_data_direction == DMA_TO_DEVICE) {
 743                         task->last_xfer = jiffies;
 744                         spin_lock(&conn->session->frwd_lock);
 745                         rc = iscsi_tcp_r2t_rsp(conn, task);
 746                         spin_unlock(&conn->session->frwd_lock);
 747                 } else
 748                         rc = ISCSI_ERR_PROTO;
 749                 break;
 750         case ISCSI_OP_LOGIN_RSP:
 751         case ISCSI_OP_TEXT_RSP:
 752         case ISCSI_OP_REJECT:
 753         case ISCSI_OP_ASYNC_EVENT:
 754                 /*
 755                  * It is possible that we could get a PDU with a buffer larger
 756                  * than 8K, but there are no targets that currently do this.
 757                  * For now we fail until we find a vendor that needs it
 758                  */
 759                 if (ISCSI_DEF_MAX_RECV_SEG_LEN < tcp_conn->in.datalen) {
 760                         iscsi_conn_printk(KERN_ERR, conn,
 761                                           "iscsi_tcp: received buffer of "
 762                                           "len %u but conn buffer is only %u "
 763                                           "(opcode %0x)\n",
 764                                           tcp_conn->in.datalen,
 765                                           ISCSI_DEF_MAX_RECV_SEG_LEN, opcode);
 766                         rc = ISCSI_ERR_PROTO;
 767                         break;
 768                 }
 769
 770                 /* If there's data coming in with the response,
 771                  * receive it to the connection's buffer.
 772                  */
 773                 if (tcp_conn->in.datalen) {
 774                         iscsi_tcp_data_recv_prep(tcp_conn);
 775                         return 0;
 776                 }
 777         /* fall through */
 778         case ISCSI_OP_LOGOUT_RSP:
 779         case ISCSI_OP_NOOP_IN:
 780         case ISCSI_OP_SCSI_TMFUNC_RSP:
 781                 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
 782                 break;
 783         default:
 784                 rc = ISCSI_ERR_BAD_OPCODE;
 785                 break;
 786         }
 787
 788         if (rc == 0) {
 789                 /* Anything that comes with data should have
 790                  * been handled above. */
 791                 if (tcp_conn->in.datalen)
 792                         return ISCSI_ERR_PROTO;
 793                 iscsi_tcp_hdr_recv_prep(tcp_conn);
 794         }
 795
 796         return rc;
 797 }
 798
 799 /**
 800  * iscsi_tcp_hdr_recv_done - process PDU header
 801  * @tcp_conn: iSCSI TCP connection
 802  * @segment: the buffer segment being processed
 803  *
 804  * This is the callback invoked when the PDU header has
 805  * been received. If the header is followed by additional
 806  * header segments, we go back for more data.
 807  */
 808 static int
 809 iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
 810                         struct iscsi_segment *segment)
 811 {
 812         struct iscsi_conn *conn = tcp_conn->iscsi_conn;
 813         struct iscsi_hdr *hdr;
 814
 815         /* Check if there are additional header segments
 816          * *prior* to computing the digest, because we
 817          * may need to go back to the caller for more.
 818          */
 819         hdr = (struct iscsi_hdr *) tcp_conn->in.hdr_buf;
 820         if (segment->copied == sizeof(struct iscsi_hdr) && hdr->hlength) {
 821                 /* Bump the header length - the caller will
 822                  * just loop around and get the AHS for us, and
 823                  * call again. */
 824                 unsigned int ahslen = hdr->hlength << 2;
 825
 826                 /* Make sure we don't overflow */
 827                 if (sizeof(*hdr) + ahslen > sizeof(tcp_conn->in.hdr_buf))
 828                         return ISCSI_ERR_AHSLEN;
 829
 830                 segment->total_size += ahslen;
 831                 segment->size += ahslen;
 832                 return 0;
 833         }
 834
 835         /* We're done processing the header. See if we're doing
 836          * header digests; if so, set up the recv_digest buffer
 837          * and go back for more. */
 838         if (conn->hdrdgst_en &&
 839             !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD)) {
 840                 if (segment->digest_len == 0) {
 841                         /*
 842                          * Even if we offload the digest processing we
 843                          * splice it in so we can increment the skb/segment
 844                          * counters in preparation for the data segment.
 845                          */
 846                         iscsi_tcp_segment_splice_digest(segment,
 847                                                         segment->recv_digest);
 848                         return 0;
 849                 }
 850
 851                 iscsi_tcp_dgst_header(tcp_conn->rx_hash, hdr,
 852                                       segment->total_copied - ISCSI_DIGEST_SIZE,
 853                                       segment->digest);
 854
 855                 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
 856                         return ISCSI_ERR_HDR_DGST;
 857         }
 858
 859         tcp_conn->in.hdr = hdr;
 860         return iscsi_tcp_hdr_dissect(conn, hdr);
 861 }
 862
 863 /**
 864  * iscsi_tcp_recv_segment_is_hdr - tests if we are reading in a header
 865  * @tcp_conn: iscsi tcp conn
 866  *
 867  * returns non zero if we are currently processing or setup to process
 868  * a header.
 869  */
 870 inline int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn)
 871 {
 872         return tcp_conn->in.segment.done == iscsi_tcp_hdr_recv_done;
 873 }
 874 EXPORT_SYMBOL_GPL(iscsi_tcp_recv_segment_is_hdr);
 875
 876 /**
 877  * iscsi_tcp_recv_skb - Process skb
 878  * @conn: iscsi connection
 879  * @skb: network buffer with header and/or data segment
 880  * @offset: offset in skb
 881  * @offloaded: bool indicating if transfer was offloaded
 882  * @status: iscsi TCP status result
 883  *
 884  * Will return status of transfer in @status. And will return
 885  * number of bytes copied.
 886  */
 887 int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
 888                        unsigned int offset, bool offloaded, int *status)
 889 {
 890         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 891         struct iscsi_segment *segment = &tcp_conn->in.segment;
 892         struct skb_seq_state seq;
 893         unsigned int consumed = 0;
 894         int rc = 0;
 895
 896         ISCSI_DBG_TCP(conn, "in %d bytes\n", skb->len - offset);
 897         /*
 898          * Update for each skb instead of pdu, because over slow networks a
 899          * data_in's data could take a while to read in. We also want to
 900          * account for r2ts.
 901          */
 902         conn->last_recv = jiffies;
 903
 904         if (unlikely(conn->suspend_rx)) {
 905                 ISCSI_DBG_TCP(conn, "Rx suspended!\n");
 906                 *status = ISCSI_TCP_SUSPENDED;
 907                 return 0;
 908         }
 909
 910         if (offloaded) {
 911                 segment->total_copied = segment->total_size;
 912                 goto segment_done;
 913         }
 914
 915         skb_prepare_seq_read(skb, offset, skb->len, &seq);
 916         while (1) {
 917                 unsigned int avail;
 918                 const u8 *ptr;
 919
 920                 avail = skb_seq_read(consumed, &ptr, &seq);
 921                 if (avail == 0) {
 922                         ISCSI_DBG_TCP(conn, "no more data avail. Consumed %d\n",
 923                                       consumed);
 924                         *status = ISCSI_TCP_SKB_DONE;
 925                         goto skb_done;
 926                 }
 927                 BUG_ON(segment->copied >= segment->size);
 928
 929                 ISCSI_DBG_TCP(conn, "skb %p ptr=%p avail=%u\n", skb, ptr,
 930                               avail);
 931                 rc = iscsi_tcp_segment_recv(tcp_conn, segment, ptr, avail);
 932                 BUG_ON(rc == 0);
 933                 consumed += rc;
 934
 935                 if (segment->total_copied >= segment->total_size) {
 936                         skb_abort_seq_read(&seq);
 937                         goto segment_done;
 938                 }
 939         }
 940
 941 segment_done:
 942         *status = ISCSI_TCP_SEGMENT_DONE;
 943         ISCSI_DBG_TCP(conn, "segment done\n");
 944         rc = segment->done(tcp_conn, segment);
 945         if (rc != 0) {
 946                 *status = ISCSI_TCP_CONN_ERR;
 947                 ISCSI_DBG_TCP(conn, "Error receiving PDU, errno=%d\n", rc);
 948                 iscsi_conn_failure(conn, rc);
 949                 return 0;
 950         }
 951         /* The done() functions sets up the next segment. */
 952
 953 skb_done:
 954         conn->rxdata_octets += consumed;
 955         return consumed;
 956 }
 957 EXPORT_SYMBOL_GPL(iscsi_tcp_recv_skb);
 958
 959 /**
 960  * iscsi_tcp_task_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
 961  * @task: scsi command task
 962  */
 963 int iscsi_tcp_task_init(struct iscsi_task *task)
 964 {
 965         struct iscsi_tcp_task *tcp_task = task->dd_data;
 966         struct iscsi_conn *conn = task->conn;
 967         struct scsi_cmnd *sc = task->sc;
 968         int err;
 969
 970         if (!sc) {
 971                 /*
 972                  * mgmt tasks do not have a scatterlist since they come
 973                  * in from the iscsi interface.
 974                  */
 975                 ISCSI_DBG_TCP(conn, "mtask deq [itt 0x%x]\n", task->itt);
 976
 977                 return conn->session->tt->init_pdu(task, 0, task->data_count);
 978         }
 979
 980         BUG_ON(kfifo_len(&tcp_task->r2tqueue));
 981         tcp_task->exp_datasn = 0;
 982
 983         /* Prepare PDU, optionally w/ immediate data */
 984         ISCSI_DBG_TCP(conn, "task deq [itt 0x%x imm %d unsol %d]\n",
 985                       task->itt, task->imm_count, task->unsol_r2t.data_length);
 986
 987         err = conn->session->tt->init_pdu(task, 0, task->imm_count);
 988         if (err)
 989                 return err;
 990         task->imm_count = 0;
 991         return 0;
 992 }
 993 EXPORT_SYMBOL_GPL(iscsi_tcp_task_init);
 994
 995 static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
 996 {
 997         struct iscsi_tcp_task *tcp_task = task->dd_data;
 998         struct iscsi_r2t_info *r2t = NULL;
 999
1000         if (iscsi_task_has_unsol_data(task))
1001                 r2t = &task->unsol_r2t;
1002         else {
1003                 spin_lock_bh(&tcp_task->queue2pool);
1004                 if (tcp_task->r2t) {
1005                         r2t = tcp_task->r2t;
1006                         /* Continue with this R2T? */
1007                         if (r2t->data_length <= r2t->sent) {
1008                                 ISCSI_DBG_TCP(task->conn,
1009                                               "  done with r2t %p\n", r2t);
1010                                 kfifo_in(&tcp_task->r2tpool.queue,
1011                                             (void *)&tcp_task->r2t,
1012                                             sizeof(void *));
1013                                 tcp_task->r2t = r2t = NULL;
1014                         }
1015                 }
1016
1017                 if (r2t == NULL) {
1018                         if (kfifo_out(&tcp_task->r2tqueue,
1019                             (void *)&tcp_task->r2t, sizeof(void *)) !=
1020                             sizeof(void *))
1021                                 r2t = NULL;
1022                         else
1023                                 r2t = tcp_task->r2t;
1024                 }
1025                 spin_unlock_bh(&tcp_task->queue2pool);
1026         }
1027
1028         return r2t;
1029 }
1030
1031 /**
1032  * iscsi_tcp_task_xmit - xmit normal PDU task
1033  * @task: iscsi command task
1034  *
1035  * We're expected to return 0 when everything was transmitted successfully,
1036  * -EAGAIN if there's still data in the queue, or != 0 for any other kind
1037  * of error.
1038  */
1039 int iscsi_tcp_task_xmit(struct iscsi_task *task)
1040 {
1041         struct iscsi_conn *conn = task->conn;
1042         struct iscsi_session *session = conn->session;
1043         struct iscsi_r2t_info *r2t;
1044         int rc = 0;
1045
1046 flush:
1047         /* Flush any pending data first. */
1048         rc = session->tt->xmit_pdu(task);
1049         if (rc < 0)
1050                 return rc;
1051
1052         /* mgmt command */
1053         if (!task->sc) {
1054                 if (task->hdr->itt == RESERVED_ITT)
1055                         iscsi_put_task(task);
1056                 return 0;
1057         }
1058
1059         /* Are we done already? */
1060         if (task->sc->sc_data_direction != DMA_TO_DEVICE)
1061                 return 0;
1062
1063         r2t = iscsi_tcp_get_curr_r2t(task);
1064         if (r2t == NULL) {
1065                 /* Waiting for more R2Ts to arrive. */
1066                 ISCSI_DBG_TCP(conn, "no R2Ts yet\n");
1067                 return 0;
1068         }
1069
1070         rc = conn->session->tt->alloc_pdu(task, ISCSI_OP_SCSI_DATA_OUT);
1071         if (rc)
1072                 return rc;
1073         iscsi_prep_data_out_pdu(task, r2t, (struct iscsi_data *) task->hdr);
1074
1075         ISCSI_DBG_TCP(conn, "sol dout %p [dsn %d itt 0x%x doff %d dlen %d]\n",
1076                       r2t, r2t->datasn - 1, task->hdr->itt,
1077                       r2t->data_offset + r2t->sent, r2t->data_count);
1078
1079         rc = conn->session->tt->init_pdu(task, r2t->data_offset + r2t->sent,
1080                                          r2t->data_count);
1081         if (rc) {
1082                 iscsi_conn_failure(conn, ISCSI_ERR_XMIT_FAILED);
1083                 return rc;
1084         }
1085
1086         r2t->sent += r2t->data_count;
1087         goto flush;
1088 }
1089 EXPORT_SYMBOL_GPL(iscsi_tcp_task_xmit);
1090
1091 struct iscsi_cls_conn *
1092 iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
1093                       uint32_t conn_idx)
1094
1095 {
1096         struct iscsi_conn *conn;
1097         struct iscsi_cls_conn *cls_conn;
1098         struct iscsi_tcp_conn *tcp_conn;
1099
1100         cls_conn = iscsi_conn_setup(cls_session,
1101                                     sizeof(*tcp_conn) + dd_data_size, conn_idx);
1102         if (!cls_conn)
1103                 return NULL;
1104         conn = cls_conn->dd_data;
1105         /*
1106          * due to strange issues with iser these are not set
1107          * in iscsi_conn_setup
1108          */
1109         conn->max_recv_dlength = ISCSI_DEF_MAX_RECV_SEG_LEN;
1110
1111         tcp_conn = conn->dd_data;
1112         tcp_conn->iscsi_conn = conn;
1113         tcp_conn->dd_data = conn->dd_data + sizeof(*tcp_conn);
1114         return cls_conn;
1115 }
1116 EXPORT_SYMBOL_GPL(iscsi_tcp_conn_setup);
1117
1118 void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn)
1119 {
1120         iscsi_conn_teardown(cls_conn);
1121 }
1122 EXPORT_SYMBOL_GPL(iscsi_tcp_conn_teardown);
1123
1124 int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session)
1125 {
1126         int i;
1127         int cmd_i;
1128
1129         /*
1130          * initialize per-task: R2T pool and xmit queue
1131          */
1132         for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
1133                 struct iscsi_task *task = session->cmds[cmd_i];
1134                 struct iscsi_tcp_task *tcp_task = task->dd_data;
1135
1136                 /*
1137                  * pre-allocated x2 as much r2ts to handle race when
1138                  * target acks DataOut faster than we data_xmit() queues
1139                  * could replenish r2tqueue.
1140                  */
1141
1142                 /* R2T pool */
1143                 if (iscsi_pool_init(&tcp_task->r2tpool,
1144                                     session->max_r2t * 2, NULL,
1145                                     sizeof(struct iscsi_r2t_info))) {
1146                         goto r2t_alloc_fail;
1147                 }
1148
1149                 /* R2T xmit queue */
1150                 if (kfifo_alloc(&tcp_task->r2tqueue,
1151                       session->max_r2t * 4 * sizeof(void*), GFP_KERNEL)) {
1152                         iscsi_pool_free(&tcp_task->r2tpool);
1153                         goto r2t_alloc_fail;
1154                 }
1155                 spin_lock_init(&tcp_task->pool2queue);
1156                 spin_lock_init(&tcp_task->queue2pool);
1157         }
1158
1159         return 0;
1160
1161 r2t_alloc_fail:
1162         for (i = 0; i < cmd_i; i++) {
1163                 struct iscsi_task *task = session->cmds[i];
1164                 struct iscsi_tcp_task *tcp_task = task->dd_data;
1165
1166                 kfifo_free(&tcp_task->r2tqueue);
1167                 iscsi_pool_free(&tcp_task->r2tpool);
1168         }
1169         return -ENOMEM;
1170 }
1171 EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_alloc);
1172
1173 void iscsi_tcp_r2tpool_free(struct iscsi_session *session)
1174 {
1175         int i;
1176
1177         for (i = 0; i < session->cmds_max; i++) {
1178                 struct iscsi_task *task = session->cmds[i];
1179                 struct iscsi_tcp_task *tcp_task = task->dd_data;
1180
1181                 kfifo_free(&tcp_task->r2tqueue);
1182                 iscsi_pool_free(&tcp_task->r2tpool);
1183         }
1184 }
1185 EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_free);
1186
1187 int iscsi_tcp_set_max_r2t(struct iscsi_conn *conn, char *buf)
1188 {
1189         struct iscsi_session *session = conn->session;
1190         unsigned short r2ts = 0;
1191
1192         sscanf(buf, "%hu", &r2ts);
1193         if (session->max_r2t == r2ts)
1194                 return 0;
1195
1196         if (!r2ts || !is_power_of_2(r2ts))
1197                 return -EINVAL;
1198
1199         session->max_r2t = r2ts;
1200         iscsi_tcp_r2tpool_free(session);
1201         return iscsi_tcp_r2tpool_alloc(session);
1202 }
1203 EXPORT_SYMBOL_GPL(iscsi_tcp_set_max_r2t);
1204
1205 void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
1206                               struct iscsi_stats *stats)
1207 {
1208         struct iscsi_conn *conn = cls_conn->dd_data;
1209
1210         stats->txdata_octets = conn->txdata_octets;
1211         stats->rxdata_octets = conn->rxdata_octets;
1212         stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
1213         stats->dataout_pdus = conn->dataout_pdus_cnt;
1214         stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
1215         stats->datain_pdus = conn->datain_pdus_cnt;
1216         stats->r2t_pdus = conn->r2t_pdus_cnt;
1217         stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
1218         stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
1219 }
1220 EXPORT_SYMBOL_GPL(iscsi_tcp_conn_get_stats);