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
  39MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, "
  40	      "Dmitry Yusupov <dmitry_yus@yahoo.com>, "
  41	      "Alex Aizman <itn780@yahoo.com>");
  42MODULE_DESCRIPTION("iSCSI/TCP data-path");
  43MODULE_LICENSE("GPL");
  44
  45static int iscsi_dbg_libtcp;
  46module_param_named(debug_libiscsi_tcp, iscsi_dbg_libtcp, int,
  47		   S_IRUGO | S_IWUSR);
  48MODULE_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
  63static 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 */
  89static inline void
  90iscsi_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 */
 109static 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
 146void 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}
 157EXPORT_SYMBOL_GPL(iscsi_tcp_segment_unmap);
 158
 159/*
 160 * Splice the digest buffer into the buffer
 161 */
 162static inline void
 163iscsi_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 */
 190int 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}
 272EXPORT_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 */
 291static int
 292iscsi_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
 313inline void
 314iscsi_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}
 323EXPORT_SYMBOL_GPL(iscsi_tcp_dgst_header);
 324
 325static inline int
 326iscsi_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 */
 344static 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
 358inline void
 359iscsi_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}
 367EXPORT_SYMBOL_GPL(iscsi_segment_init_linear);
 368
 369inline int
 370iscsi_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}
 390EXPORT_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 */
 400void 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}
 409EXPORT_SYMBOL_GPL(iscsi_tcp_hdr_recv_prep);
 410
 411/*
 412 * Handle incoming reply to any other type of command
 413 */
 414static int
 415iscsi_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
 433static void
 434iscsi_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 */
 454void 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}
 479EXPORT_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 */
 486static 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 */
 529static 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	if (!iscsi_get_task(task)) {
 562		spin_unlock(&session->back_lock);
 563		/* Let the path that got the early rsp complete it */
 564		return 0;
 565	}
 566
 567	tcp_conn = conn->dd_data;
 568	rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr;
 569	/* fill-in new R2T associated with the task */
 570	iscsi_update_cmdsn(session, (struct iscsi_nopin *)rhdr);
 571	spin_unlock(&session->back_lock);
 572
 573	if (tcp_conn->in.datalen) {
 574		iscsi_conn_printk(KERN_ERR, conn,
 575				  "invalid R2t with datalen %d\n",
 576				  tcp_conn->in.datalen);
 577		rc = ISCSI_ERR_DATALEN;
 578		goto put_task;
 579	}
 580
 581	tcp_task = task->dd_data;
 582	r2tsn = be32_to_cpu(rhdr->r2tsn);
 583	if (tcp_task->exp_datasn != r2tsn){
 584		ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->r2tsn(%d)\n",
 585			      tcp_task->exp_datasn, r2tsn);
 586		rc = ISCSI_ERR_R2TSN;
 587		goto put_task;
 588	}
 589
 590	if (session->state != ISCSI_STATE_LOGGED_IN) {
 591		iscsi_conn_printk(KERN_INFO, conn,
 592				  "dropping R2T itt %d in recovery.\n",
 593				  task->itt);
 594		rc = 0;
 595		goto put_task;
 596	}
 597
 598	data_length = be32_to_cpu(rhdr->data_length);
 599	if (data_length == 0) {
 600		iscsi_conn_printk(KERN_ERR, conn,
 601				  "invalid R2T with zero data len\n");
 602		rc = ISCSI_ERR_DATALEN;
 603		goto put_task;
 604	}
 605
 606	if (data_length > session->max_burst)
 607		ISCSI_DBG_TCP(conn, "invalid R2T with data len %u and max "
 608			      "burst %u. Attempting to execute request.\n",
 609			      data_length, session->max_burst);
 610
 611	data_offset = be32_to_cpu(rhdr->data_offset);
 612	if (data_offset + data_length > task->sc->sdb.length) {
 613		iscsi_conn_printk(KERN_ERR, conn,
 614				  "invalid R2T with data len %u at offset %u "
 615				  "and total length %d\n", data_length,
 616				  data_offset, task->sc->sdb.length);
 617		rc = ISCSI_ERR_DATALEN;
 618		goto put_task;
 619	}
 620
 621	spin_lock(&tcp_task->pool2queue);
 622	rc = kfifo_out(&tcp_task->r2tpool.queue, (void *)&r2t, sizeof(void *));
 623	if (!rc) {
 624		iscsi_conn_printk(KERN_ERR, conn, "Could not allocate R2T. "
 625				  "Target has sent more R2Ts than it "
 626				  "negotiated for or driver has leaked.\n");
 627		spin_unlock(&tcp_task->pool2queue);
 628		rc = ISCSI_ERR_PROTO;
 629		goto put_task;
 630	}
 631
 632	r2t->exp_statsn = rhdr->statsn;
 633	r2t->data_length = data_length;
 634	r2t->data_offset = data_offset;
 635
 636	r2t->ttt = rhdr->ttt; /* no flip */
 637	r2t->datasn = 0;
 638	r2t->sent = 0;
 639
 640	tcp_task->exp_datasn = r2tsn + 1;
 641	kfifo_in(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*));
 642	conn->r2t_pdus_cnt++;
 643	spin_unlock(&tcp_task->pool2queue);
 644
 645	iscsi_requeue_task(task);
 646	return 0;
 647
 648put_task:
 649	iscsi_put_task(task);
 650	return rc;
 651}
 652
 653/*
 654 * Handle incoming reply to DataIn command
 655 */
 656static int
 657iscsi_tcp_process_data_in(struct iscsi_tcp_conn *tcp_conn,
 658			  struct iscsi_segment *segment)
 659{
 660	struct iscsi_conn *conn = tcp_conn->iscsi_conn;
 661	struct iscsi_hdr *hdr = tcp_conn->in.hdr;
 662	int rc;
 663
 664	if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
 665		return ISCSI_ERR_DATA_DGST;
 666
 667	/* check for non-exceptional status */
 668	if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
 669		rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, NULL, 0);
 670		if (rc)
 671			return rc;
 672	}
 673
 674	iscsi_tcp_hdr_recv_prep(tcp_conn);
 675	return 0;
 676}
 677
 678/**
 679 * iscsi_tcp_hdr_dissect - process PDU header
 680 * @conn: iSCSI connection
 681 * @hdr: PDU header
 682 *
 683 * This function analyzes the header of the PDU received,
 684 * and performs several sanity checks. If the PDU is accompanied
 685 * by data, the receive buffer is set up to copy the incoming data
 686 * to the correct location.
 687 */
 688static int
 689iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
 690{
 691	int rc = 0, opcode, ahslen;
 692	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 693	struct iscsi_task *task;
 694
 695	/* verify PDU length */
 696	tcp_conn->in.datalen = ntoh24(hdr->dlength);
 697	if (tcp_conn->in.datalen > conn->max_recv_dlength) {
 698		iscsi_conn_printk(KERN_ERR, conn,
 699				  "iscsi_tcp: datalen %d > %d\n",
 700				  tcp_conn->in.datalen, conn->max_recv_dlength);
 701		return ISCSI_ERR_DATALEN;
 702	}
 703
 704	/* Additional header segments. So far, we don't
 705	 * process additional headers.
 706	 */
 707	ahslen = hdr->hlength << 2;
 708
 709	opcode = hdr->opcode & ISCSI_OPCODE_MASK;
 710	/* verify itt (itt encoding: age+cid+itt) */
 711	rc = iscsi_verify_itt(conn, hdr->itt);
 712	if (rc)
 713		return rc;
 714
 715	ISCSI_DBG_TCP(conn, "opcode 0x%x ahslen %d datalen %d\n",
 716		      opcode, ahslen, tcp_conn->in.datalen);
 717
 718	switch(opcode) {
 719	case ISCSI_OP_SCSI_DATA_IN:
 720		spin_lock(&conn->session->back_lock);
 721		task = iscsi_itt_to_ctask(conn, hdr->itt);
 722		if (!task)
 723			rc = ISCSI_ERR_BAD_ITT;
 724		else
 725			rc = iscsi_tcp_data_in(conn, task);
 726		if (rc) {
 727			spin_unlock(&conn->session->back_lock);
 728			break;
 729		}
 730
 731		if (tcp_conn->in.datalen) {
 732			struct iscsi_tcp_task *tcp_task = task->dd_data;
 733			struct ahash_request *rx_hash = NULL;
 734			struct scsi_data_buffer *sdb = &task->sc->sdb;
 735
 736			/*
 737			 * Setup copy of Data-In into the struct scsi_cmnd
 738			 * Scatterlist case:
 739			 * We set up the iscsi_segment to point to the next
 740			 * scatterlist entry to copy to. As we go along,
 741			 * we move on to the next scatterlist entry and
 742			 * update the digest per-entry.
 743			 */
 744			if (conn->datadgst_en &&
 745			    !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
 746				rx_hash = tcp_conn->rx_hash;
 747
 748			ISCSI_DBG_TCP(conn, "iscsi_tcp_begin_data_in( "
 749				     "offset=%d, datalen=%d)\n",
 750				      tcp_task->data_offset,
 751				      tcp_conn->in.datalen);
 752			task->last_xfer = jiffies;
 753			rc = iscsi_segment_seek_sg(&tcp_conn->in.segment,
 754						   sdb->table.sgl,
 755						   sdb->table.nents,
 756						   tcp_task->data_offset,
 757						   tcp_conn->in.datalen,
 758						   iscsi_tcp_process_data_in,
 759						   rx_hash);
 760			spin_unlock(&conn->session->back_lock);
 761			return rc;
 762		}
 763		rc = __iscsi_complete_pdu(conn, hdr, NULL, 0);
 764		spin_unlock(&conn->session->back_lock);
 765		break;
 766	case ISCSI_OP_SCSI_CMD_RSP:
 767		if (tcp_conn->in.datalen) {
 768			iscsi_tcp_data_recv_prep(tcp_conn);
 769			return 0;
 770		}
 771		rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
 772		break;
 773	case ISCSI_OP_R2T:
 774		if (ahslen) {
 775			rc = ISCSI_ERR_AHSLEN;
 776			break;
 777		}
 778		rc = iscsi_tcp_r2t_rsp(conn, hdr);
 779		break;
 780	case ISCSI_OP_LOGIN_RSP:
 781	case ISCSI_OP_TEXT_RSP:
 782	case ISCSI_OP_REJECT:
 783	case ISCSI_OP_ASYNC_EVENT:
 784		/*
 785		 * It is possible that we could get a PDU with a buffer larger
 786		 * than 8K, but there are no targets that currently do this.
 787		 * For now we fail until we find a vendor that needs it
 788		 */
 789		if (ISCSI_DEF_MAX_RECV_SEG_LEN < tcp_conn->in.datalen) {
 790			iscsi_conn_printk(KERN_ERR, conn,
 791					  "iscsi_tcp: received buffer of "
 792					  "len %u but conn buffer is only %u "
 793					  "(opcode %0x)\n",
 794					  tcp_conn->in.datalen,
 795					  ISCSI_DEF_MAX_RECV_SEG_LEN, opcode);
 796			rc = ISCSI_ERR_PROTO;
 797			break;
 798		}
 799
 800		/* If there's data coming in with the response,
 801		 * receive it to the connection's buffer.
 802		 */
 803		if (tcp_conn->in.datalen) {
 804			iscsi_tcp_data_recv_prep(tcp_conn);
 805			return 0;
 806		}
 807		fallthrough;
 808	case ISCSI_OP_LOGOUT_RSP:
 809	case ISCSI_OP_NOOP_IN:
 810	case ISCSI_OP_SCSI_TMFUNC_RSP:
 811		rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
 812		break;
 813	default:
 814		rc = ISCSI_ERR_BAD_OPCODE;
 815		break;
 816	}
 817
 818	if (rc == 0) {
 819		/* Anything that comes with data should have
 820		 * been handled above. */
 821		if (tcp_conn->in.datalen)
 822			return ISCSI_ERR_PROTO;
 823		iscsi_tcp_hdr_recv_prep(tcp_conn);
 824	}
 825
 826	return rc;
 827}
 828
 829/**
 830 * iscsi_tcp_hdr_recv_done - process PDU header
 831 * @tcp_conn: iSCSI TCP connection
 832 * @segment: the buffer segment being processed
 833 *
 834 * This is the callback invoked when the PDU header has
 835 * been received. If the header is followed by additional
 836 * header segments, we go back for more data.
 837 */
 838static int
 839iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
 840			struct iscsi_segment *segment)
 841{
 842	struct iscsi_conn *conn = tcp_conn->iscsi_conn;
 843	struct iscsi_hdr *hdr;
 844
 845	/* Check if there are additional header segments
 846	 * *prior* to computing the digest, because we
 847	 * may need to go back to the caller for more.
 848	 */
 849	hdr = (struct iscsi_hdr *) tcp_conn->in.hdr_buf;
 850	if (segment->copied == sizeof(struct iscsi_hdr) && hdr->hlength) {
 851		/* Bump the header length - the caller will
 852		 * just loop around and get the AHS for us, and
 853		 * call again. */
 854		unsigned int ahslen = hdr->hlength << 2;
 855
 856		/* Make sure we don't overflow */
 857		if (sizeof(*hdr) + ahslen > sizeof(tcp_conn->in.hdr_buf))
 858			return ISCSI_ERR_AHSLEN;
 859
 860		segment->total_size += ahslen;
 861		segment->size += ahslen;
 862		return 0;
 863	}
 864
 865	/* We're done processing the header. See if we're doing
 866	 * header digests; if so, set up the recv_digest buffer
 867	 * and go back for more. */
 868	if (conn->hdrdgst_en &&
 869	    !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD)) {
 870		if (segment->digest_len == 0) {
 871			/*
 872			 * Even if we offload the digest processing we
 873			 * splice it in so we can increment the skb/segment
 874			 * counters in preparation for the data segment.
 875			 */
 876			iscsi_tcp_segment_splice_digest(segment,
 877							segment->recv_digest);
 878			return 0;
 879		}
 880
 881		iscsi_tcp_dgst_header(tcp_conn->rx_hash, hdr,
 882				      segment->total_copied - ISCSI_DIGEST_SIZE,
 883				      segment->digest);
 884
 885		if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
 886			return ISCSI_ERR_HDR_DGST;
 887	}
 888
 889	tcp_conn->in.hdr = hdr;
 890	return iscsi_tcp_hdr_dissect(conn, hdr);
 891}
 892
 893/**
 894 * iscsi_tcp_recv_segment_is_hdr - tests if we are reading in a header
 895 * @tcp_conn: iscsi tcp conn
 896 *
 897 * returns non zero if we are currently processing or setup to process
 898 * a header.
 899 */
 900inline int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn)
 901{
 902	return tcp_conn->in.segment.done == iscsi_tcp_hdr_recv_done;
 903}
 904EXPORT_SYMBOL_GPL(iscsi_tcp_recv_segment_is_hdr);
 905
 906/**
 907 * iscsi_tcp_recv_skb - Process skb
 908 * @conn: iscsi connection
 909 * @skb: network buffer with header and/or data segment
 910 * @offset: offset in skb
 911 * @offloaded: bool indicating if transfer was offloaded
 912 * @status: iscsi TCP status result
 913 *
 914 * Will return status of transfer in @status. And will return
 915 * number of bytes copied.
 916 */
 917int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
 918		       unsigned int offset, bool offloaded, int *status)
 919{
 920	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 921	struct iscsi_segment *segment = &tcp_conn->in.segment;
 922	struct skb_seq_state seq;
 923	unsigned int consumed = 0;
 924	int rc = 0;
 925
 926	ISCSI_DBG_TCP(conn, "in %d bytes\n", skb->len - offset);
 927	/*
 928	 * Update for each skb instead of pdu, because over slow networks a
 929	 * data_in's data could take a while to read in. We also want to
 930	 * account for r2ts.
 931	 */
 932	conn->last_recv = jiffies;
 933
 934	if (unlikely(test_bit(ISCSI_CONN_FLAG_SUSPEND_RX, &conn->flags))) {
 935		ISCSI_DBG_TCP(conn, "Rx suspended!\n");
 936		*status = ISCSI_TCP_SUSPENDED;
 937		return 0;
 938	}
 939
 940	if (offloaded) {
 941		segment->total_copied = segment->total_size;
 942		goto segment_done;
 943	}
 944
 945	skb_prepare_seq_read(skb, offset, skb->len, &seq);
 946	while (1) {
 947		unsigned int avail;
 948		const u8 *ptr;
 949
 950		avail = skb_seq_read(consumed, &ptr, &seq);
 951		if (avail == 0) {
 952			ISCSI_DBG_TCP(conn, "no more data avail. Consumed %d\n",
 953				      consumed);
 954			*status = ISCSI_TCP_SKB_DONE;
 955			goto skb_done;
 956		}
 957		BUG_ON(segment->copied >= segment->size);
 958
 959		ISCSI_DBG_TCP(conn, "skb %p ptr=%p avail=%u\n", skb, ptr,
 960			      avail);
 961		rc = iscsi_tcp_segment_recv(tcp_conn, segment, ptr, avail);
 962		BUG_ON(rc == 0);
 963		consumed += rc;
 964
 965		if (segment->total_copied >= segment->total_size) {
 966			skb_abort_seq_read(&seq);
 967			goto segment_done;
 968		}
 969	}
 970
 971segment_done:
 972	*status = ISCSI_TCP_SEGMENT_DONE;
 973	ISCSI_DBG_TCP(conn, "segment done\n");
 974	rc = segment->done(tcp_conn, segment);
 975	if (rc != 0) {
 976		*status = ISCSI_TCP_CONN_ERR;
 977		ISCSI_DBG_TCP(conn, "Error receiving PDU, errno=%d\n", rc);
 978		iscsi_conn_failure(conn, rc);
 979		return 0;
 980	}
 981	/* The done() functions sets up the next segment. */
 982
 983skb_done:
 984	conn->rxdata_octets += consumed;
 985	return consumed;
 986}
 987EXPORT_SYMBOL_GPL(iscsi_tcp_recv_skb);
 988
 989/**
 990 * iscsi_tcp_task_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
 991 * @task: scsi command task
 992 */
 993int iscsi_tcp_task_init(struct iscsi_task *task)
 994{
 995	struct iscsi_tcp_task *tcp_task = task->dd_data;
 996	struct iscsi_conn *conn = task->conn;
 997	struct scsi_cmnd *sc = task->sc;
 998	int err;
 999
1000	if (!sc) {
1001		/*
1002		 * mgmt tasks do not have a scatterlist since they come
1003		 * in from the iscsi interface.
1004		 */
1005		ISCSI_DBG_TCP(conn, "mtask deq [itt 0x%x]\n", task->itt);
1006
1007		return conn->session->tt->init_pdu(task, 0, task->data_count);
1008	}
1009
1010	BUG_ON(kfifo_len(&tcp_task->r2tqueue));
1011	tcp_task->exp_datasn = 0;
1012
1013	/* Prepare PDU, optionally w/ immediate data */
1014	ISCSI_DBG_TCP(conn, "task deq [itt 0x%x imm %d unsol %d]\n",
1015		      task->itt, task->imm_count, task->unsol_r2t.data_length);
1016
1017	err = conn->session->tt->init_pdu(task, 0, task->imm_count);
1018	if (err)
1019		return err;
1020	task->imm_count = 0;
1021	return 0;
1022}
1023EXPORT_SYMBOL_GPL(iscsi_tcp_task_init);
1024
1025static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
1026{
1027	struct iscsi_tcp_task *tcp_task = task->dd_data;
1028	struct iscsi_r2t_info *r2t = NULL;
1029
1030	if (iscsi_task_has_unsol_data(task))
1031		r2t = &task->unsol_r2t;
1032	else {
1033		spin_lock_bh(&tcp_task->queue2pool);
1034		if (tcp_task->r2t) {
1035			r2t = tcp_task->r2t;
1036			/* Continue with this R2T? */
1037			if (r2t->data_length <= r2t->sent) {
1038				ISCSI_DBG_TCP(task->conn,
1039					      "  done with r2t %p\n", r2t);
1040				kfifo_in(&tcp_task->r2tpool.queue,
1041					    (void *)&tcp_task->r2t,
1042					    sizeof(void *));
1043				tcp_task->r2t = r2t = NULL;
1044			}
1045		}
1046
1047		if (r2t == NULL) {
1048			if (kfifo_out(&tcp_task->r2tqueue,
1049			    (void *)&tcp_task->r2t, sizeof(void *)) !=
1050			    sizeof(void *))
1051				r2t = NULL;
1052			else
1053				r2t = tcp_task->r2t;
1054		}
1055		spin_unlock_bh(&tcp_task->queue2pool);
1056	}
1057
1058	return r2t;
1059}
1060
1061/**
1062 * iscsi_tcp_task_xmit - xmit normal PDU task
1063 * @task: iscsi command task
1064 *
1065 * We're expected to return 0 when everything was transmitted successfully,
1066 * -EAGAIN if there's still data in the queue, or != 0 for any other kind
1067 * of error.
1068 */
1069int iscsi_tcp_task_xmit(struct iscsi_task *task)
1070{
1071	struct iscsi_conn *conn = task->conn;
1072	struct iscsi_session *session = conn->session;
1073	struct iscsi_r2t_info *r2t;
1074	int rc = 0;
1075
1076flush:
1077	/* Flush any pending data first. */
1078	rc = session->tt->xmit_pdu(task);
1079	if (rc < 0)
1080		return rc;
1081
1082	/* mgmt command */
1083	if (!task->sc) {
1084		if (task->hdr->itt == RESERVED_ITT)
1085			iscsi_put_task(task);
1086		return 0;
1087	}
1088
1089	/* Are we done already? */
1090	if (task->sc->sc_data_direction != DMA_TO_DEVICE)
1091		return 0;
1092
1093	r2t = iscsi_tcp_get_curr_r2t(task);
1094	if (r2t == NULL) {
1095		/* Waiting for more R2Ts to arrive. */
1096		ISCSI_DBG_TCP(conn, "no R2Ts yet\n");
1097		return 0;
1098	}
1099
1100	rc = conn->session->tt->alloc_pdu(task, ISCSI_OP_SCSI_DATA_OUT);
1101	if (rc)
1102		return rc;
1103	iscsi_prep_data_out_pdu(task, r2t, (struct iscsi_data *) task->hdr);
1104
1105	ISCSI_DBG_TCP(conn, "sol dout %p [dsn %d itt 0x%x doff %d dlen %d]\n",
1106		      r2t, r2t->datasn - 1, task->hdr->itt,
1107		      r2t->data_offset + r2t->sent, r2t->data_count);
1108
1109	rc = conn->session->tt->init_pdu(task, r2t->data_offset + r2t->sent,
1110					 r2t->data_count);
1111	if (rc) {
1112		iscsi_conn_failure(conn, ISCSI_ERR_XMIT_FAILED);
1113		return rc;
1114	}
1115
1116	r2t->sent += r2t->data_count;
1117	goto flush;
1118}
1119EXPORT_SYMBOL_GPL(iscsi_tcp_task_xmit);
1120
1121struct iscsi_cls_conn *
1122iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
1123		      uint32_t conn_idx)
1124
1125{
1126	struct iscsi_conn *conn;
1127	struct iscsi_cls_conn *cls_conn;
1128	struct iscsi_tcp_conn *tcp_conn;
1129
1130	cls_conn = iscsi_conn_setup(cls_session,
1131				    sizeof(*tcp_conn) + dd_data_size, conn_idx);
1132	if (!cls_conn)
1133		return NULL;
1134	conn = cls_conn->dd_data;
1135	/*
1136	 * due to strange issues with iser these are not set
1137	 * in iscsi_conn_setup
1138	 */
1139	conn->max_recv_dlength = ISCSI_DEF_MAX_RECV_SEG_LEN;
1140
1141	tcp_conn = conn->dd_data;
1142	tcp_conn->iscsi_conn = conn;
1143	tcp_conn->dd_data = conn->dd_data + sizeof(*tcp_conn);
1144	return cls_conn;
1145}
1146EXPORT_SYMBOL_GPL(iscsi_tcp_conn_setup);
1147
1148void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn)
1149{
1150	iscsi_conn_teardown(cls_conn);
1151}
1152EXPORT_SYMBOL_GPL(iscsi_tcp_conn_teardown);
1153
1154int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session)
1155{
1156	int i;
1157	int cmd_i;
1158
1159	/*
1160	 * initialize per-task: R2T pool and xmit queue
1161	 */
1162	for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
1163	        struct iscsi_task *task = session->cmds[cmd_i];
1164		struct iscsi_tcp_task *tcp_task = task->dd_data;
1165
1166		/*
1167		 * pre-allocated x2 as much r2ts to handle race when
1168		 * target acks DataOut faster than we data_xmit() queues
1169		 * could replenish r2tqueue.
1170		 */
1171
1172		/* R2T pool */
1173		if (iscsi_pool_init(&tcp_task->r2tpool,
1174				    session->max_r2t * 2, NULL,
1175				    sizeof(struct iscsi_r2t_info))) {
1176			goto r2t_alloc_fail;
1177		}
1178
1179		/* R2T xmit queue */
1180		if (kfifo_alloc(&tcp_task->r2tqueue,
1181		      session->max_r2t * 4 * sizeof(void*), GFP_KERNEL)) {
1182			iscsi_pool_free(&tcp_task->r2tpool);
1183			goto r2t_alloc_fail;
1184		}
1185		spin_lock_init(&tcp_task->pool2queue);
1186		spin_lock_init(&tcp_task->queue2pool);
1187	}
1188
1189	return 0;
1190
1191r2t_alloc_fail:
1192	for (i = 0; i < cmd_i; i++) {
1193		struct iscsi_task *task = session->cmds[i];
1194		struct iscsi_tcp_task *tcp_task = task->dd_data;
1195
1196		kfifo_free(&tcp_task->r2tqueue);
1197		iscsi_pool_free(&tcp_task->r2tpool);
1198	}
1199	return -ENOMEM;
1200}
1201EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_alloc);
1202
1203void iscsi_tcp_r2tpool_free(struct iscsi_session *session)
1204{
1205	int i;
1206
1207	for (i = 0; i < session->cmds_max; i++) {
1208		struct iscsi_task *task = session->cmds[i];
1209		struct iscsi_tcp_task *tcp_task = task->dd_data;
1210
1211		kfifo_free(&tcp_task->r2tqueue);
1212		iscsi_pool_free(&tcp_task->r2tpool);
1213	}
1214}
1215EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_free);
1216
1217int iscsi_tcp_set_max_r2t(struct iscsi_conn *conn, char *buf)
1218{
1219	struct iscsi_session *session = conn->session;
1220	unsigned short r2ts = 0;
1221
1222	sscanf(buf, "%hu", &r2ts);
1223	if (session->max_r2t == r2ts)
1224		return 0;
1225
1226	if (!r2ts || !is_power_of_2(r2ts))
1227		return -EINVAL;
1228
1229	session->max_r2t = r2ts;
1230	iscsi_tcp_r2tpool_free(session);
1231	return iscsi_tcp_r2tpool_alloc(session);
1232}
1233EXPORT_SYMBOL_GPL(iscsi_tcp_set_max_r2t);
1234
1235void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
1236			      struct iscsi_stats *stats)
1237{
1238	struct iscsi_conn *conn = cls_conn->dd_data;
1239
1240	stats->txdata_octets = conn->txdata_octets;
1241	stats->rxdata_octets = conn->rxdata_octets;
1242	stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
1243	stats->dataout_pdus = conn->dataout_pdus_cnt;
1244	stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
1245	stats->datain_pdus = conn->datain_pdus_cnt;
1246	stats->r2t_pdus = conn->r2t_pdus_cnt;
1247	stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
1248	stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
1249}
1250EXPORT_SYMBOL_GPL(iscsi_tcp_conn_get_stats);