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  * @hdr: PDU header
 528  */
 529 static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
 530 {
 531         struct iscsi_session *session = conn->session;
 532         struct iscsi_tcp_task *tcp_task;
 533         struct iscsi_tcp_conn *tcp_conn;
 534         struct iscsi_r2t_rsp *rhdr;
 535         struct iscsi_r2t_info *r2t;
 536         struct iscsi_task *task;
 537         u32 data_length;
 538         u32 data_offset;
 539         int r2tsn;
 540         int rc;
 541
 542         spin_lock(&session->back_lock);
 543         task = iscsi_itt_to_ctask(conn, hdr->itt);
 544         if (!task) {
 545                 spin_unlock(&session->back_lock);
 546                 return ISCSI_ERR_BAD_ITT;
 547         } else if (task->sc->sc_data_direction != DMA_TO_DEVICE) {
 548                 spin_unlock(&session->back_lock);
 549                 return ISCSI_ERR_PROTO;
 550         }
 551         /*
 552          * A bad target might complete the cmd before we have handled R2Ts
 553          * so get a ref to the task that will be dropped in the xmit path.
 554          */
 555         if (task->state != ISCSI_TASK_RUNNING) {
 556                 spin_unlock(&session->back_lock);
 557                 /* Let the path that got the early rsp complete it */
 558                 return 0;
 559         }
 560         task->last_xfer = jiffies;
 561         __iscsi_get_task(task);
 562
 563         tcp_conn = conn->dd_data;
 564         rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr;
 565         /* fill-in new R2T associated with the task */
 566         iscsi_update_cmdsn(session, (struct iscsi_nopin *)rhdr);
 567         spin_unlock(&session->back_lock);
 568
 569         if (tcp_conn->in.datalen) {
 570                 iscsi_conn_printk(KERN_ERR, conn,
 571                                   "invalid R2t with datalen %d\n",
 572                                   tcp_conn->in.datalen);
 573                 rc = ISCSI_ERR_DATALEN;
 574                 goto put_task;
 575         }
 576
 577         tcp_task = task->dd_data;
 578         r2tsn = be32_to_cpu(rhdr->r2tsn);
 579         if (tcp_task->exp_datasn != r2tsn){
 580                 ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->r2tsn(%d)\n",
 581                               tcp_task->exp_datasn, r2tsn);
 582                 rc = ISCSI_ERR_R2TSN;
 583                 goto put_task;
 584         }
 585
 586         if (session->state != ISCSI_STATE_LOGGED_IN) {
 587                 iscsi_conn_printk(KERN_INFO, conn,
 588                                   "dropping R2T itt %d in recovery.\n",
 589                                   task->itt);
 590                 rc = 0;
 591                 goto put_task;
 592         }
 593
 594         data_length = be32_to_cpu(rhdr->data_length);
 595         if (data_length == 0) {
 596                 iscsi_conn_printk(KERN_ERR, conn,
 597                                   "invalid R2T with zero data len\n");
 598                 rc = ISCSI_ERR_DATALEN;
 599                 goto put_task;
 600         }
 601
 602         if (data_length > session->max_burst)
 603                 ISCSI_DBG_TCP(conn, "invalid R2T with data len %u and max "
 604                               "burst %u. Attempting to execute request.\n",
 605                               data_length, session->max_burst);
 606
 607         data_offset = be32_to_cpu(rhdr->data_offset);
 608         if (data_offset + data_length > task->sc->sdb.length) {
 609                 iscsi_conn_printk(KERN_ERR, conn,
 610                                   "invalid R2T with data len %u at offset %u "
 611                                   "and total length %d\n", data_length,
 612                                   data_offset, task->sc->sdb.length);
 613                 rc = ISCSI_ERR_DATALEN;
 614                 goto put_task;
 615         }
 616
 617         spin_lock(&tcp_task->pool2queue);
 618         rc = kfifo_out(&tcp_task->r2tpool.queue, (void *)&r2t, sizeof(void *));
 619         if (!rc) {
 620                 iscsi_conn_printk(KERN_ERR, conn, "Could not allocate R2T. "
 621                                   "Target has sent more R2Ts than it "
 622                                   "negotiated for or driver has leaked.\n");
 623                 spin_unlock(&tcp_task->pool2queue);
 624                 rc = ISCSI_ERR_PROTO;
 625                 goto put_task;
 626         }
 627
 628         r2t->exp_statsn = rhdr->statsn;
 629         r2t->data_length = data_length;
 630         r2t->data_offset = data_offset;
 631
 632         r2t->ttt = rhdr->ttt; /* no flip */
 633         r2t->datasn = 0;
 634         r2t->sent = 0;
 635
 636         tcp_task->exp_datasn = r2tsn + 1;
 637         kfifo_in(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*));
 638         conn->r2t_pdus_cnt++;
 639         spin_unlock(&tcp_task->pool2queue);
 640
 641         iscsi_requeue_task(task);
 642         return 0;
 643
 644 put_task:
 645         iscsi_put_task(task);
 646         return rc;
 647 }
 648
 649 /*
 650  * Handle incoming reply to DataIn command
 651  */
 652 static int
 653 iscsi_tcp_process_data_in(struct iscsi_tcp_conn *tcp_conn,
 654                           struct iscsi_segment *segment)
 655 {
 656         struct iscsi_conn *conn = tcp_conn->iscsi_conn;
 657         struct iscsi_hdr *hdr = tcp_conn->in.hdr;
 658         int rc;
 659
 660         if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
 661                 return ISCSI_ERR_DATA_DGST;
 662
 663         /* check for non-exceptional status */
 664         if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
 665                 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, NULL, 0);
 666                 if (rc)
 667                         return rc;
 668         }
 669
 670         iscsi_tcp_hdr_recv_prep(tcp_conn);
 671         return 0;
 672 }
 673
 674 /**
 675  * iscsi_tcp_hdr_dissect - process PDU header
 676  * @conn: iSCSI connection
 677  * @hdr: PDU header
 678  *
 679  * This function analyzes the header of the PDU received,
 680  * and performs several sanity checks. If the PDU is accompanied
 681  * by data, the receive buffer is set up to copy the incoming data
 682  * to the correct location.
 683  */
 684 static int
 685 iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
 686 {
 687         int rc = 0, opcode, ahslen;
 688         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 689         struct iscsi_task *task;
 690
 691         /* verify PDU length */
 692         tcp_conn->in.datalen = ntoh24(hdr->dlength);
 693         if (tcp_conn->in.datalen > conn->max_recv_dlength) {
 694                 iscsi_conn_printk(KERN_ERR, conn,
 695                                   "iscsi_tcp: datalen %d > %d\n",
 696                                   tcp_conn->in.datalen, conn->max_recv_dlength);
 697                 return ISCSI_ERR_DATALEN;
 698         }
 699
 700         /* Additional header segments. So far, we don't
 701          * process additional headers.
 702          */
 703         ahslen = hdr->hlength << 2;
 704
 705         opcode = hdr->opcode & ISCSI_OPCODE_MASK;
 706         /* verify itt (itt encoding: age+cid+itt) */
 707         rc = iscsi_verify_itt(conn, hdr->itt);
 708         if (rc)
 709                 return rc;
 710
 711         ISCSI_DBG_TCP(conn, "opcode 0x%x ahslen %d datalen %d\n",
 712                       opcode, ahslen, tcp_conn->in.datalen);
 713
 714         switch(opcode) {
 715         case ISCSI_OP_SCSI_DATA_IN:
 716                 spin_lock(&conn->session->back_lock);
 717                 task = iscsi_itt_to_ctask(conn, hdr->itt);
 718                 if (!task)
 719                         rc = ISCSI_ERR_BAD_ITT;
 720                 else
 721                         rc = iscsi_tcp_data_in(conn, task);
 722                 if (rc) {
 723                         spin_unlock(&conn->session->back_lock);
 724                         break;
 725                 }
 726
 727                 if (tcp_conn->in.datalen) {
 728                         struct iscsi_tcp_task *tcp_task = task->dd_data;
 729                         struct ahash_request *rx_hash = NULL;
 730                         struct scsi_data_buffer *sdb = &task->sc->sdb;
 731
 732                         /*
 733                          * Setup copy of Data-In into the struct scsi_cmnd
 734                          * Scatterlist case:
 735                          * We set up the iscsi_segment to point to the next
 736                          * scatterlist entry to copy to. As we go along,
 737                          * we move on to the next scatterlist entry and
 738                          * update the digest per-entry.
 739                          */
 740                         if (conn->datadgst_en &&
 741                             !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
 742                                 rx_hash = tcp_conn->rx_hash;
 743
 744                         ISCSI_DBG_TCP(conn, "iscsi_tcp_begin_data_in( "
 745                                      "offset=%d, datalen=%d)\n",
 746                                       tcp_task->data_offset,
 747                                       tcp_conn->in.datalen);
 748                         task->last_xfer = jiffies;
 749                         rc = iscsi_segment_seek_sg(&tcp_conn->in.segment,
 750                                                    sdb->table.sgl,
 751                                                    sdb->table.nents,
 752                                                    tcp_task->data_offset,
 753                                                    tcp_conn->in.datalen,
 754                                                    iscsi_tcp_process_data_in,
 755                                                    rx_hash);
 756                         spin_unlock(&conn->session->back_lock);
 757                         return rc;
 758                 }
 759                 rc = __iscsi_complete_pdu(conn, hdr, NULL, 0);
 760                 spin_unlock(&conn->session->back_lock);
 761                 break;
 762         case ISCSI_OP_SCSI_CMD_RSP:
 763                 if (tcp_conn->in.datalen) {
 764                         iscsi_tcp_data_recv_prep(tcp_conn);
 765                         return 0;
 766                 }
 767                 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
 768                 break;
 769         case ISCSI_OP_R2T:
 770                 if (ahslen) {
 771                         rc = ISCSI_ERR_AHSLEN;
 772                         break;
 773                 }
 774                 rc = iscsi_tcp_r2t_rsp(conn, hdr);
 775                 break;
 776         case ISCSI_OP_LOGIN_RSP:
 777         case ISCSI_OP_TEXT_RSP:
 778         case ISCSI_OP_REJECT:
 779         case ISCSI_OP_ASYNC_EVENT:
 780                 /*
 781                  * It is possible that we could get a PDU with a buffer larger
 782                  * than 8K, but there are no targets that currently do this.
 783                  * For now we fail until we find a vendor that needs it
 784                  */
 785                 if (ISCSI_DEF_MAX_RECV_SEG_LEN < tcp_conn->in.datalen) {
 786                         iscsi_conn_printk(KERN_ERR, conn,
 787                                           "iscsi_tcp: received buffer of "
 788                                           "len %u but conn buffer is only %u "
 789                                           "(opcode %0x)\n",
 790                                           tcp_conn->in.datalen,
 791                                           ISCSI_DEF_MAX_RECV_SEG_LEN, opcode);
 792                         rc = ISCSI_ERR_PROTO;
 793                         break;
 794                 }
 795
 796                 /* If there's data coming in with the response,
 797                  * receive it to the connection's buffer.
 798                  */
 799                 if (tcp_conn->in.datalen) {
 800                         iscsi_tcp_data_recv_prep(tcp_conn);
 801                         return 0;
 802                 }
 803                 fallthrough;
 804         case ISCSI_OP_LOGOUT_RSP:
 805         case ISCSI_OP_NOOP_IN:
 806         case ISCSI_OP_SCSI_TMFUNC_RSP:
 807                 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
 808                 break;
 809         default:
 810                 rc = ISCSI_ERR_BAD_OPCODE;
 811                 break;
 812         }
 813
 814         if (rc == 0) {
 815                 /* Anything that comes with data should have
 816                  * been handled above. */
 817                 if (tcp_conn->in.datalen)
 818                         return ISCSI_ERR_PROTO;
 819                 iscsi_tcp_hdr_recv_prep(tcp_conn);
 820         }
 821
 822         return rc;
 823 }
 824
 825 /**
 826  * iscsi_tcp_hdr_recv_done - process PDU header
 827  * @tcp_conn: iSCSI TCP connection
 828  * @segment: the buffer segment being processed
 829  *
 830  * This is the callback invoked when the PDU header has
 831  * been received. If the header is followed by additional
 832  * header segments, we go back for more data.
 833  */
 834 static int
 835 iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
 836                         struct iscsi_segment *segment)
 837 {
 838         struct iscsi_conn *conn = tcp_conn->iscsi_conn;
 839         struct iscsi_hdr *hdr;
 840
 841         /* Check if there are additional header segments
 842          * *prior* to computing the digest, because we
 843          * may need to go back to the caller for more.
 844          */
 845         hdr = (struct iscsi_hdr *) tcp_conn->in.hdr_buf;
 846         if (segment->copied == sizeof(struct iscsi_hdr) && hdr->hlength) {
 847                 /* Bump the header length - the caller will
 848                  * just loop around and get the AHS for us, and
 849                  * call again. */
 850                 unsigned int ahslen = hdr->hlength << 2;
 851
 852                 /* Make sure we don't overflow */
 853                 if (sizeof(*hdr) + ahslen > sizeof(tcp_conn->in.hdr_buf))
 854                         return ISCSI_ERR_AHSLEN;
 855
 856                 segment->total_size += ahslen;
 857                 segment->size += ahslen;
 858                 return 0;
 859         }
 860
 861         /* We're done processing the header. See if we're doing
 862          * header digests; if so, set up the recv_digest buffer
 863          * and go back for more. */
 864         if (conn->hdrdgst_en &&
 865             !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD)) {
 866                 if (segment->digest_len == 0) {
 867                         /*
 868                          * Even if we offload the digest processing we
 869                          * splice it in so we can increment the skb/segment
 870                          * counters in preparation for the data segment.
 871                          */
 872                         iscsi_tcp_segment_splice_digest(segment,
 873                                                         segment->recv_digest);
 874                         return 0;
 875                 }
 876
 877                 iscsi_tcp_dgst_header(tcp_conn->rx_hash, hdr,
 878                                       segment->total_copied - ISCSI_DIGEST_SIZE,
 879                                       segment->digest);
 880
 881                 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
 882                         return ISCSI_ERR_HDR_DGST;
 883         }
 884
 885         tcp_conn->in.hdr = hdr;
 886         return iscsi_tcp_hdr_dissect(conn, hdr);
 887 }
 888
 889 /**
 890  * iscsi_tcp_recv_segment_is_hdr - tests if we are reading in a header
 891  * @tcp_conn: iscsi tcp conn
 892  *
 893  * returns non zero if we are currently processing or setup to process
 894  * a header.
 895  */
 896 inline int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn)
 897 {
 898         return tcp_conn->in.segment.done == iscsi_tcp_hdr_recv_done;
 899 }
 900 EXPORT_SYMBOL_GPL(iscsi_tcp_recv_segment_is_hdr);
 901
 902 /**
 903  * iscsi_tcp_recv_skb - Process skb
 904  * @conn: iscsi connection
 905  * @skb: network buffer with header and/or data segment
 906  * @offset: offset in skb
 907  * @offloaded: bool indicating if transfer was offloaded
 908  * @status: iscsi TCP status result
 909  *
 910  * Will return status of transfer in @status. And will return
 911  * number of bytes copied.
 912  */
 913 int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
 914                        unsigned int offset, bool offloaded, int *status)
 915 {
 916         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 917         struct iscsi_segment *segment = &tcp_conn->in.segment;
 918         struct skb_seq_state seq;
 919         unsigned int consumed = 0;
 920         int rc = 0;
 921
 922         ISCSI_DBG_TCP(conn, "in %d bytes\n", skb->len - offset);
 923         /*
 924          * Update for each skb instead of pdu, because over slow networks a
 925          * data_in's data could take a while to read in. We also want to
 926          * account for r2ts.
 927          */
 928         conn->last_recv = jiffies;
 929
 930         if (unlikely(conn->suspend_rx)) {
 931                 ISCSI_DBG_TCP(conn, "Rx suspended!\n");
 932                 *status = ISCSI_TCP_SUSPENDED;
 933                 return 0;
 934         }
 935
 936         if (offloaded) {
 937                 segment->total_copied = segment->total_size;
 938                 goto segment_done;
 939         }
 940
 941         skb_prepare_seq_read(skb, offset, skb->len, &seq);
 942         while (1) {
 943                 unsigned int avail;
 944                 const u8 *ptr;
 945
 946                 avail = skb_seq_read(consumed, &ptr, &seq);
 947                 if (avail == 0) {
 948                         ISCSI_DBG_TCP(conn, "no more data avail. Consumed %d\n",
 949                                       consumed);
 950                         *status = ISCSI_TCP_SKB_DONE;
 951                         goto skb_done;
 952                 }
 953                 BUG_ON(segment->copied >= segment->size);
 954
 955                 ISCSI_DBG_TCP(conn, "skb %p ptr=%p avail=%u\n", skb, ptr,
 956                               avail);
 957                 rc = iscsi_tcp_segment_recv(tcp_conn, segment, ptr, avail);
 958                 BUG_ON(rc == 0);
 959                 consumed += rc;
 960
 961                 if (segment->total_copied >= segment->total_size) {
 962                         skb_abort_seq_read(&seq);
 963                         goto segment_done;
 964                 }
 965         }
 966
 967 segment_done:
 968         *status = ISCSI_TCP_SEGMENT_DONE;
 969         ISCSI_DBG_TCP(conn, "segment done\n");
 970         rc = segment->done(tcp_conn, segment);
 971         if (rc != 0) {
 972                 *status = ISCSI_TCP_CONN_ERR;
 973                 ISCSI_DBG_TCP(conn, "Error receiving PDU, errno=%d\n", rc);
 974                 iscsi_conn_failure(conn, rc);
 975                 return 0;
 976         }
 977         /* The done() functions sets up the next segment. */
 978
 979 skb_done:
 980         conn->rxdata_octets += consumed;
 981         return consumed;
 982 }
 983 EXPORT_SYMBOL_GPL(iscsi_tcp_recv_skb);
 984
 985 /**
 986  * iscsi_tcp_task_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
 987  * @task: scsi command task
 988  */
 989 int iscsi_tcp_task_init(struct iscsi_task *task)
 990 {
 991         struct iscsi_tcp_task *tcp_task = task->dd_data;
 992         struct iscsi_conn *conn = task->conn;
 993         struct scsi_cmnd *sc = task->sc;
 994         int err;
 995
 996         if (!sc) {
 997                 /*
 998                  * mgmt tasks do not have a scatterlist since they come
 999                  * in from the iscsi interface.
1000                  */
1001                 ISCSI_DBG_TCP(conn, "mtask deq [itt 0x%x]\n", task->itt);
1002
1003                 return conn->session->tt->init_pdu(task, 0, task->data_count);
1004         }
1005
1006         BUG_ON(kfifo_len(&tcp_task->r2tqueue));
1007         tcp_task->exp_datasn = 0;
1008
1009         /* Prepare PDU, optionally w/ immediate data */
1010         ISCSI_DBG_TCP(conn, "task deq [itt 0x%x imm %d unsol %d]\n",
1011                       task->itt, task->imm_count, task->unsol_r2t.data_length);
1012
1013         err = conn->session->tt->init_pdu(task, 0, task->imm_count);
1014         if (err)
1015                 return err;
1016         task->imm_count = 0;
1017         return 0;
1018 }
1019 EXPORT_SYMBOL_GPL(iscsi_tcp_task_init);
1020
1021 static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
1022 {
1023         struct iscsi_tcp_task *tcp_task = task->dd_data;
1024         struct iscsi_r2t_info *r2t = NULL;
1025
1026         if (iscsi_task_has_unsol_data(task))
1027                 r2t = &task->unsol_r2t;
1028         else {
1029                 spin_lock_bh(&tcp_task->queue2pool);
1030                 if (tcp_task->r2t) {
1031                         r2t = tcp_task->r2t;
1032                         /* Continue with this R2T? */
1033                         if (r2t->data_length <= r2t->sent) {
1034                                 ISCSI_DBG_TCP(task->conn,
1035                                               "  done with r2t %p\n", r2t);
1036                                 kfifo_in(&tcp_task->r2tpool.queue,
1037                                             (void *)&tcp_task->r2t,
1038                                             sizeof(void *));
1039                                 tcp_task->r2t = r2t = NULL;
1040                         }
1041                 }
1042
1043                 if (r2t == NULL) {
1044                         if (kfifo_out(&tcp_task->r2tqueue,
1045                             (void *)&tcp_task->r2t, sizeof(void *)) !=
1046                             sizeof(void *))
1047                                 r2t = NULL;
1048                         else
1049                                 r2t = tcp_task->r2t;
1050                 }
1051                 spin_unlock_bh(&tcp_task->queue2pool);
1052         }
1053
1054         return r2t;
1055 }
1056
1057 /**
1058  * iscsi_tcp_task_xmit - xmit normal PDU task
1059  * @task: iscsi command task
1060  *
1061  * We're expected to return 0 when everything was transmitted successfully,
1062  * -EAGAIN if there's still data in the queue, or != 0 for any other kind
1063  * of error.
1064  */
1065 int iscsi_tcp_task_xmit(struct iscsi_task *task)
1066 {
1067         struct iscsi_conn *conn = task->conn;
1068         struct iscsi_session *session = conn->session;
1069         struct iscsi_r2t_info *r2t;
1070         int rc = 0;
1071
1072 flush:
1073         /* Flush any pending data first. */
1074         rc = session->tt->xmit_pdu(task);
1075         if (rc < 0)
1076                 return rc;
1077
1078         /* mgmt command */
1079         if (!task->sc) {
1080                 if (task->hdr->itt == RESERVED_ITT)
1081                         iscsi_put_task(task);
1082                 return 0;
1083         }
1084
1085         /* Are we done already? */
1086         if (task->sc->sc_data_direction != DMA_TO_DEVICE)
1087                 return 0;
1088
1089         r2t = iscsi_tcp_get_curr_r2t(task);
1090         if (r2t == NULL) {
1091                 /* Waiting for more R2Ts to arrive. */
1092                 ISCSI_DBG_TCP(conn, "no R2Ts yet\n");
1093                 return 0;
1094         }
1095
1096         rc = conn->session->tt->alloc_pdu(task, ISCSI_OP_SCSI_DATA_OUT);
1097         if (rc)
1098                 return rc;
1099         iscsi_prep_data_out_pdu(task, r2t, (struct iscsi_data *) task->hdr);
1100
1101         ISCSI_DBG_TCP(conn, "sol dout %p [dsn %d itt 0x%x doff %d dlen %d]\n",
1102                       r2t, r2t->datasn - 1, task->hdr->itt,
1103                       r2t->data_offset + r2t->sent, r2t->data_count);
1104
1105         rc = conn->session->tt->init_pdu(task, r2t->data_offset + r2t->sent,
1106                                          r2t->data_count);
1107         if (rc) {
1108                 iscsi_conn_failure(conn, ISCSI_ERR_XMIT_FAILED);
1109                 return rc;
1110         }
1111
1112         r2t->sent += r2t->data_count;
1113         goto flush;
1114 }
1115 EXPORT_SYMBOL_GPL(iscsi_tcp_task_xmit);
1116
1117 struct iscsi_cls_conn *
1118 iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
1119                       uint32_t conn_idx)
1120
1121 {
1122         struct iscsi_conn *conn;
1123         struct iscsi_cls_conn *cls_conn;
1124         struct iscsi_tcp_conn *tcp_conn;
1125
1126         cls_conn = iscsi_conn_setup(cls_session,
1127                                     sizeof(*tcp_conn) + dd_data_size, conn_idx);
1128         if (!cls_conn)
1129                 return NULL;
1130         conn = cls_conn->dd_data;
1131         /*
1132          * due to strange issues with iser these are not set
1133          * in iscsi_conn_setup
1134          */
1135         conn->max_recv_dlength = ISCSI_DEF_MAX_RECV_SEG_LEN;
1136
1137         tcp_conn = conn->dd_data;
1138         tcp_conn->iscsi_conn = conn;
1139         tcp_conn->dd_data = conn->dd_data + sizeof(*tcp_conn);
1140         return cls_conn;
1141 }
1142 EXPORT_SYMBOL_GPL(iscsi_tcp_conn_setup);
1143
1144 void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn)
1145 {
1146         iscsi_conn_teardown(cls_conn);
1147 }
1148 EXPORT_SYMBOL_GPL(iscsi_tcp_conn_teardown);
1149
1150 int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session)
1151 {
1152         int i;
1153         int cmd_i;
1154
1155         /*
1156          * initialize per-task: R2T pool and xmit queue
1157          */
1158         for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
1159                 struct iscsi_task *task = session->cmds[cmd_i];
1160                 struct iscsi_tcp_task *tcp_task = task->dd_data;
1161
1162                 /*
1163                  * pre-allocated x2 as much r2ts to handle race when
1164                  * target acks DataOut faster than we data_xmit() queues
1165                  * could replenish r2tqueue.
1166                  */
1167
1168                 /* R2T pool */
1169                 if (iscsi_pool_init(&tcp_task->r2tpool,
1170                                     session->max_r2t * 2, NULL,
1171                                     sizeof(struct iscsi_r2t_info))) {
1172                         goto r2t_alloc_fail;
1173                 }
1174
1175                 /* R2T xmit queue */
1176                 if (kfifo_alloc(&tcp_task->r2tqueue,
1177                       session->max_r2t * 4 * sizeof(void*), GFP_KERNEL)) {
1178                         iscsi_pool_free(&tcp_task->r2tpool);
1179                         goto r2t_alloc_fail;
1180                 }
1181                 spin_lock_init(&tcp_task->pool2queue);
1182                 spin_lock_init(&tcp_task->queue2pool);
1183         }
1184
1185         return 0;
1186
1187 r2t_alloc_fail:
1188         for (i = 0; i < cmd_i; i++) {
1189                 struct iscsi_task *task = session->cmds[i];
1190                 struct iscsi_tcp_task *tcp_task = task->dd_data;
1191
1192                 kfifo_free(&tcp_task->r2tqueue);
1193                 iscsi_pool_free(&tcp_task->r2tpool);
1194         }
1195         return -ENOMEM;
1196 }
1197 EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_alloc);
1198
1199 void iscsi_tcp_r2tpool_free(struct iscsi_session *session)
1200 {
1201         int i;
1202
1203         for (i = 0; i < session->cmds_max; i++) {
1204                 struct iscsi_task *task = session->cmds[i];
1205                 struct iscsi_tcp_task *tcp_task = task->dd_data;
1206
1207                 kfifo_free(&tcp_task->r2tqueue);
1208                 iscsi_pool_free(&tcp_task->r2tpool);
1209         }
1210 }
1211 EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_free);
1212
1213 int iscsi_tcp_set_max_r2t(struct iscsi_conn *conn, char *buf)
1214 {
1215         struct iscsi_session *session = conn->session;
1216         unsigned short r2ts = 0;
1217
1218         sscanf(buf, "%hu", &r2ts);
1219         if (session->max_r2t == r2ts)
1220                 return 0;
1221
1222         if (!r2ts || !is_power_of_2(r2ts))
1223                 return -EINVAL;
1224
1225         session->max_r2t = r2ts;
1226         iscsi_tcp_r2tpool_free(session);
1227         return iscsi_tcp_r2tpool_alloc(session);
1228 }
1229 EXPORT_SYMBOL_GPL(iscsi_tcp_set_max_r2t);
1230
1231 void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
1232                               struct iscsi_stats *stats)
1233 {
1234         struct iscsi_conn *conn = cls_conn->dd_data;
1235
1236         stats->txdata_octets = conn->txdata_octets;
1237         stats->rxdata_octets = conn->rxdata_octets;
1238         stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
1239         stats->dataout_pdus = conn->dataout_pdus_cnt;
1240         stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
1241         stats->datain_pdus = conn->datain_pdus_cnt;
1242         stats->r2t_pdus = conn->r2t_pdus_cnt;
1243         stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
1244         stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
1245 }
1246 EXPORT_SYMBOL_GPL(iscsi_tcp_conn_get_stats);