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Mike Christiea081c132008-12-02 00:32:11 -06001/*
2 * iSCSI over TCP/IP Data-Path lib
3 *
4 * Copyright (C) 2004 Dmitry Yusupov
5 * Copyright (C) 2004 Alex Aizman
6 * Copyright (C) 2005 - 2006 Mike Christie
7 * Copyright (C) 2006 Red Hat, Inc. All rights reserved.
8 * maintained by open-iscsi@googlegroups.com
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published
12 * by the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 *
20 * See the file COPYING included with this distribution for more details.
21 *
22 * Credits:
23 * Christoph Hellwig
24 * FUJITA Tomonori
25 * Arne Redlich
26 * Zhenyu Wang
27 */
28
29#include <linux/types.h>
30#include <linux/list.h>
31#include <linux/inet.h>
32#include <linux/file.h>
33#include <linux/blkdev.h>
34#include <linux/crypto.h>
35#include <linux/delay.h>
36#include <linux/kfifo.h>
37#include <linux/scatterlist.h>
38#include <net/tcp.h>
39#include <scsi/scsi_cmnd.h>
40#include <scsi/scsi_device.h>
41#include <scsi/scsi_host.h>
42#include <scsi/scsi.h>
43#include <scsi/scsi_transport_iscsi.h>
44
45#include "iscsi_tcp.h"
46
47MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, "
48 "Dmitry Yusupov <dmitry_yus@yahoo.com>, "
49 "Alex Aizman <itn780@yahoo.com>");
50MODULE_DESCRIPTION("iSCSI/TCP data-path");
51MODULE_LICENSE("GPL");
Mike Christiea081c132008-12-02 00:32:11 -060052
Mike Christie0ab1c252009-03-05 14:45:59 -060053static int iscsi_dbg_libtcp;
54module_param_named(debug_libiscsi_tcp, iscsi_dbg_libtcp, int,
55 S_IRUGO | S_IWUSR);
56MODULE_PARM_DESC(debug_libiscsi_tcp, "Turn on debugging for libiscsi_tcp "
57 "module. Set to 1 to turn on, and zero to turn off. Default "
58 "is off.");
59
60#define ISCSI_DBG_TCP(_conn, dbg_fmt, arg...) \
61 do { \
62 if (iscsi_dbg_libtcp) \
63 iscsi_conn_printk(KERN_INFO, _conn, \
64 "%s " dbg_fmt, \
65 __func__, ##arg); \
66 } while (0);
Mike Christiea081c132008-12-02 00:32:11 -060067
68static int iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
69 struct iscsi_segment *segment);
70
71/*
72 * Scatterlist handling: inside the iscsi_segment, we
73 * remember an index into the scatterlist, and set data/size
74 * to the current scatterlist entry. For highmem pages, we
75 * kmap as needed.
76 *
77 * Note that the page is unmapped when we return from
78 * TCP's data_ready handler, so we may end up mapping and
79 * unmapping the same page repeatedly. The whole reason
80 * for this is that we shouldn't keep the page mapped
81 * outside the softirq.
82 */
83
84/**
85 * iscsi_tcp_segment_init_sg - init indicated scatterlist entry
86 * @segment: the buffer object
87 * @sg: scatterlist
88 * @offset: byte offset into that sg entry
89 *
90 * This function sets up the segment so that subsequent
91 * data is copied to the indicated sg entry, at the given
92 * offset.
93 */
94static inline void
95iscsi_tcp_segment_init_sg(struct iscsi_segment *segment,
96 struct scatterlist *sg, unsigned int offset)
97{
98 segment->sg = sg;
99 segment->sg_offset = offset;
100 segment->size = min(sg->length - offset,
101 segment->total_size - segment->total_copied);
102 segment->data = NULL;
103}
104
105/**
106 * iscsi_tcp_segment_map - map the current S/G page
107 * @segment: iscsi_segment
108 * @recv: 1 if called from recv path
109 *
110 * We only need to possibly kmap data if scatter lists are being used,
111 * because the iscsi passthrough and internal IO paths will never use high
112 * mem pages.
113 */
114static void iscsi_tcp_segment_map(struct iscsi_segment *segment, int recv)
115{
116 struct scatterlist *sg;
117
118 if (segment->data != NULL || !segment->sg)
119 return;
120
121 sg = segment->sg;
122 BUG_ON(segment->sg_mapped);
123 BUG_ON(sg->length == 0);
124
125 /*
126 * If the page count is greater than one it is ok to send
127 * to the network layer's zero copy send path. If not we
128 * have to go the slow sendmsg path. We always map for the
129 * recv path.
130 */
131 if (page_count(sg_page(sg)) >= 1 && !recv)
132 return;
133
Mike Christiea081c132008-12-02 00:32:11 -0600134 segment->sg_mapped = kmap_atomic(sg_page(sg), KM_SOFTIRQ0);
135 segment->data = segment->sg_mapped + sg->offset + segment->sg_offset;
136}
137
138void iscsi_tcp_segment_unmap(struct iscsi_segment *segment)
139{
Mike Christiea081c132008-12-02 00:32:11 -0600140 if (segment->sg_mapped) {
Mike Christiea081c132008-12-02 00:32:11 -0600141 kunmap_atomic(segment->sg_mapped, KM_SOFTIRQ0);
142 segment->sg_mapped = NULL;
143 segment->data = NULL;
144 }
145}
146EXPORT_SYMBOL_GPL(iscsi_tcp_segment_unmap);
147
148/*
149 * Splice the digest buffer into the buffer
150 */
151static inline void
152iscsi_tcp_segment_splice_digest(struct iscsi_segment *segment, void *digest)
153{
154 segment->data = digest;
155 segment->digest_len = ISCSI_DIGEST_SIZE;
156 segment->total_size += ISCSI_DIGEST_SIZE;
157 segment->size = ISCSI_DIGEST_SIZE;
158 segment->copied = 0;
159 segment->sg = NULL;
160 segment->hash = NULL;
161}
162
163/**
164 * iscsi_tcp_segment_done - check whether the segment is complete
Mike Christie6df19a72008-12-02 00:32:16 -0600165 * @tcp_conn: iscsi tcp connection
Mike Christiea081c132008-12-02 00:32:11 -0600166 * @segment: iscsi segment to check
167 * @recv: set to one of this is called from the recv path
168 * @copied: number of bytes copied
169 *
170 * Check if we're done receiving this segment. If the receive
171 * buffer is full but we expect more data, move on to the
172 * next entry in the scatterlist.
173 *
174 * If the amount of data we received isn't a multiple of 4,
175 * we will transparently receive the pad bytes, too.
176 *
177 * This function must be re-entrant.
178 */
Mike Christie6df19a72008-12-02 00:32:16 -0600179int iscsi_tcp_segment_done(struct iscsi_tcp_conn *tcp_conn,
180 struct iscsi_segment *segment, int recv,
Mike Christiea081c132008-12-02 00:32:11 -0600181 unsigned copied)
182{
Mike Christiea081c132008-12-02 00:32:11 -0600183 struct scatterlist sg;
184 unsigned int pad;
185
Mike Christie0ab1c252009-03-05 14:45:59 -0600186 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "copied %u %u size %u %s\n",
187 segment->copied, copied, segment->size,
188 recv ? "recv" : "xmit");
Mike Christiea081c132008-12-02 00:32:11 -0600189 if (segment->hash && copied) {
190 /*
191 * If a segment is kmapd we must unmap it before sending
192 * to the crypto layer since that will try to kmap it again.
193 */
194 iscsi_tcp_segment_unmap(segment);
195
196 if (!segment->data) {
197 sg_init_table(&sg, 1);
198 sg_set_page(&sg, sg_page(segment->sg), copied,
199 segment->copied + segment->sg_offset +
200 segment->sg->offset);
201 } else
202 sg_init_one(&sg, segment->data + segment->copied,
203 copied);
204 crypto_hash_update(segment->hash, &sg, copied);
205 }
206
207 segment->copied += copied;
208 if (segment->copied < segment->size) {
209 iscsi_tcp_segment_map(segment, recv);
210 return 0;
211 }
212
213 segment->total_copied += segment->copied;
214 segment->copied = 0;
215 segment->size = 0;
216
217 /* Unmap the current scatterlist page, if there is one. */
218 iscsi_tcp_segment_unmap(segment);
219
220 /* Do we have more scatterlist entries? */
Mike Christie0ab1c252009-03-05 14:45:59 -0600221 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "total copied %u total size %u\n",
222 segment->total_copied, segment->total_size);
Mike Christiea081c132008-12-02 00:32:11 -0600223 if (segment->total_copied < segment->total_size) {
224 /* Proceed to the next entry in the scatterlist. */
225 iscsi_tcp_segment_init_sg(segment, sg_next(segment->sg),
226 0);
227 iscsi_tcp_segment_map(segment, recv);
228 BUG_ON(segment->size == 0);
229 return 0;
230 }
231
232 /* Do we need to handle padding? */
Mike Christie6df19a72008-12-02 00:32:16 -0600233 if (!(tcp_conn->iscsi_conn->session->tt->caps & CAP_PADDING_OFFLOAD)) {
234 pad = iscsi_padding(segment->total_copied);
235 if (pad != 0) {
Mike Christie0ab1c252009-03-05 14:45:59 -0600236 ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
237 "consume %d pad bytes\n", pad);
Mike Christie6df19a72008-12-02 00:32:16 -0600238 segment->total_size += pad;
239 segment->size = pad;
Karen Xie28568302009-01-10 19:06:07 -0800240 segment->data = segment->padbuf;
Mike Christie6df19a72008-12-02 00:32:16 -0600241 return 0;
242 }
Mike Christiea081c132008-12-02 00:32:11 -0600243 }
244
245 /*
246 * Set us up for transferring the data digest. hdr digest
247 * is completely handled in hdr done function.
248 */
249 if (segment->hash) {
250 crypto_hash_final(segment->hash, segment->digest);
251 iscsi_tcp_segment_splice_digest(segment,
252 recv ? segment->recv_digest : segment->digest);
253 return 0;
254 }
255
256 return 1;
257}
258EXPORT_SYMBOL_GPL(iscsi_tcp_segment_done);
259
260/**
261 * iscsi_tcp_segment_recv - copy data to segment
262 * @tcp_conn: the iSCSI TCP connection
263 * @segment: the buffer to copy to
264 * @ptr: data pointer
265 * @len: amount of data available
266 *
267 * This function copies up to @len bytes to the
268 * given buffer, and returns the number of bytes
269 * consumed, which can actually be less than @len.
270 *
271 * If hash digest is enabled, the function will update the
272 * hash while copying.
273 * Combining these two operations doesn't buy us a lot (yet),
274 * but in the future we could implement combined copy+crc,
275 * just way we do for network layer checksums.
276 */
277static int
278iscsi_tcp_segment_recv(struct iscsi_tcp_conn *tcp_conn,
279 struct iscsi_segment *segment, const void *ptr,
280 unsigned int len)
281{
282 unsigned int copy = 0, copied = 0;
283
Mike Christie6df19a72008-12-02 00:32:16 -0600284 while (!iscsi_tcp_segment_done(tcp_conn, segment, 1, copy)) {
Mike Christiea081c132008-12-02 00:32:11 -0600285 if (copied == len) {
Mike Christie0ab1c252009-03-05 14:45:59 -0600286 ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
287 "copied %d bytes\n", len);
Mike Christiea081c132008-12-02 00:32:11 -0600288 break;
289 }
290
291 copy = min(len - copied, segment->size - segment->copied);
Mike Christie0ab1c252009-03-05 14:45:59 -0600292 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "copying %d\n", copy);
Mike Christiea081c132008-12-02 00:32:11 -0600293 memcpy(segment->data + segment->copied, ptr + copied, copy);
294 copied += copy;
295 }
296 return copied;
297}
298
299inline void
300iscsi_tcp_dgst_header(struct hash_desc *hash, const void *hdr, size_t hdrlen,
301 unsigned char digest[ISCSI_DIGEST_SIZE])
302{
303 struct scatterlist sg;
304
305 sg_init_one(&sg, hdr, hdrlen);
306 crypto_hash_digest(hash, &sg, hdrlen, digest);
307}
308EXPORT_SYMBOL_GPL(iscsi_tcp_dgst_header);
309
310static inline int
311iscsi_tcp_dgst_verify(struct iscsi_tcp_conn *tcp_conn,
312 struct iscsi_segment *segment)
313{
314 if (!segment->digest_len)
315 return 1;
316
317 if (memcmp(segment->recv_digest, segment->digest,
318 segment->digest_len)) {
Mike Christie0ab1c252009-03-05 14:45:59 -0600319 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "digest mismatch\n");
Mike Christiea081c132008-12-02 00:32:11 -0600320 return 0;
321 }
322
323 return 1;
324}
325
326/*
327 * Helper function to set up segment buffer
328 */
329static inline void
330__iscsi_segment_init(struct iscsi_segment *segment, size_t size,
331 iscsi_segment_done_fn_t *done, struct hash_desc *hash)
332{
333 memset(segment, 0, sizeof(*segment));
334 segment->total_size = size;
335 segment->done = done;
336
337 if (hash) {
338 segment->hash = hash;
339 crypto_hash_init(hash);
340 }
341}
342
343inline void
344iscsi_segment_init_linear(struct iscsi_segment *segment, void *data,
345 size_t size, iscsi_segment_done_fn_t *done,
346 struct hash_desc *hash)
347{
348 __iscsi_segment_init(segment, size, done, hash);
349 segment->data = data;
350 segment->size = size;
351}
352EXPORT_SYMBOL_GPL(iscsi_segment_init_linear);
353
354inline int
355iscsi_segment_seek_sg(struct iscsi_segment *segment,
356 struct scatterlist *sg_list, unsigned int sg_count,
357 unsigned int offset, size_t size,
358 iscsi_segment_done_fn_t *done, struct hash_desc *hash)
359{
360 struct scatterlist *sg;
361 unsigned int i;
362
Mike Christiea081c132008-12-02 00:32:11 -0600363 __iscsi_segment_init(segment, size, done, hash);
364 for_each_sg(sg_list, sg, sg_count, i) {
Mike Christiea081c132008-12-02 00:32:11 -0600365 if (offset < sg->length) {
366 iscsi_tcp_segment_init_sg(segment, sg, offset);
367 return 0;
368 }
369 offset -= sg->length;
370 }
371
372 return ISCSI_ERR_DATA_OFFSET;
373}
374EXPORT_SYMBOL_GPL(iscsi_segment_seek_sg);
375
376/**
377 * iscsi_tcp_hdr_recv_prep - prep segment for hdr reception
378 * @tcp_conn: iscsi connection to prep for
379 *
380 * This function always passes NULL for the hash argument, because when this
381 * function is called we do not yet know the final size of the header and want
382 * to delay the digest processing until we know that.
383 */
384void iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn)
385{
Mike Christie0ab1c252009-03-05 14:45:59 -0600386 ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
387 "(%s)\n", tcp_conn->iscsi_conn->hdrdgst_en ?
388 "digest enabled" : "digest disabled");
Mike Christiea081c132008-12-02 00:32:11 -0600389 iscsi_segment_init_linear(&tcp_conn->in.segment,
390 tcp_conn->in.hdr_buf, sizeof(struct iscsi_hdr),
391 iscsi_tcp_hdr_recv_done, NULL);
392}
393EXPORT_SYMBOL_GPL(iscsi_tcp_hdr_recv_prep);
394
395/*
396 * Handle incoming reply to any other type of command
397 */
398static int
399iscsi_tcp_data_recv_done(struct iscsi_tcp_conn *tcp_conn,
400 struct iscsi_segment *segment)
401{
402 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
403 int rc = 0;
404
405 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
406 return ISCSI_ERR_DATA_DGST;
407
408 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr,
409 conn->data, tcp_conn->in.datalen);
410 if (rc)
411 return rc;
412
413 iscsi_tcp_hdr_recv_prep(tcp_conn);
414 return 0;
415}
416
417static void
418iscsi_tcp_data_recv_prep(struct iscsi_tcp_conn *tcp_conn)
419{
420 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
421 struct hash_desc *rx_hash = NULL;
422
423 if (conn->datadgst_en &
424 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
425 rx_hash = tcp_conn->rx_hash;
426
427 iscsi_segment_init_linear(&tcp_conn->in.segment,
428 conn->data, tcp_conn->in.datalen,
429 iscsi_tcp_data_recv_done, rx_hash);
430}
431
432/**
433 * iscsi_tcp_cleanup_task - free tcp_task resources
434 * @task: iscsi task
435 *
436 * must be called with session lock
437 */
438void iscsi_tcp_cleanup_task(struct iscsi_task *task)
439{
440 struct iscsi_tcp_task *tcp_task = task->dd_data;
441 struct iscsi_r2t_info *r2t;
442
443 /* nothing to do for mgmt or pending tasks */
444 if (!task->sc || task->state == ISCSI_TASK_PENDING)
445 return;
446
447 /* flush task's r2t queues */
448 while (__kfifo_get(tcp_task->r2tqueue, (void*)&r2t, sizeof(void*))) {
449 __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
450 sizeof(void*));
Mike Christie0ab1c252009-03-05 14:45:59 -0600451 ISCSI_DBG_TCP(task->conn, "pending r2t dropped\n");
Mike Christiea081c132008-12-02 00:32:11 -0600452 }
453
454 r2t = tcp_task->r2t;
455 if (r2t != NULL) {
456 __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
457 sizeof(void*));
458 tcp_task->r2t = NULL;
459 }
460}
461EXPORT_SYMBOL_GPL(iscsi_tcp_cleanup_task);
462
463/**
464 * iscsi_tcp_data_in - SCSI Data-In Response processing
465 * @conn: iscsi connection
466 * @task: scsi command task
467 */
468static int iscsi_tcp_data_in(struct iscsi_conn *conn, struct iscsi_task *task)
469{
470 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
471 struct iscsi_tcp_task *tcp_task = task->dd_data;
472 struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)tcp_conn->in.hdr;
473 int datasn = be32_to_cpu(rhdr->datasn);
474 unsigned total_in_length = scsi_in(task->sc)->length;
475
476 iscsi_update_cmdsn(conn->session, (struct iscsi_nopin*)rhdr);
477 if (tcp_conn->in.datalen == 0)
478 return 0;
479
480 if (tcp_task->exp_datasn != datasn) {
Mike Christie0ab1c252009-03-05 14:45:59 -0600481 ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->datasn(%d)"
482 "\n", tcp_task->exp_datasn, datasn);
Mike Christiea081c132008-12-02 00:32:11 -0600483 return ISCSI_ERR_DATASN;
484 }
485
486 tcp_task->exp_datasn++;
487
488 tcp_task->data_offset = be32_to_cpu(rhdr->offset);
489 if (tcp_task->data_offset + tcp_conn->in.datalen > total_in_length) {
Mike Christie0ab1c252009-03-05 14:45:59 -0600490 ISCSI_DBG_TCP(conn, "data_offset(%d) + data_len(%d) > "
491 "total_length_in(%d)\n", tcp_task->data_offset,
492 tcp_conn->in.datalen, total_in_length);
Mike Christiea081c132008-12-02 00:32:11 -0600493 return ISCSI_ERR_DATA_OFFSET;
494 }
495
496 conn->datain_pdus_cnt++;
497 return 0;
498}
499
500/**
501 * iscsi_tcp_r2t_rsp - iSCSI R2T Response processing
502 * @conn: iscsi connection
503 * @task: scsi command task
504 */
505static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
506{
507 struct iscsi_session *session = conn->session;
508 struct iscsi_tcp_task *tcp_task = task->dd_data;
509 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
510 struct iscsi_r2t_rsp *rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr;
511 struct iscsi_r2t_info *r2t;
512 int r2tsn = be32_to_cpu(rhdr->r2tsn);
513 int rc;
514
515 if (tcp_conn->in.datalen) {
516 iscsi_conn_printk(KERN_ERR, conn,
517 "invalid R2t with datalen %d\n",
518 tcp_conn->in.datalen);
519 return ISCSI_ERR_DATALEN;
520 }
521
522 if (tcp_task->exp_datasn != r2tsn){
Mike Christie0ab1c252009-03-05 14:45:59 -0600523 ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->r2tsn(%d)\n",
524 tcp_task->exp_datasn, r2tsn);
Mike Christiea081c132008-12-02 00:32:11 -0600525 return ISCSI_ERR_R2TSN;
526 }
527
528 /* fill-in new R2T associated with the task */
529 iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr);
530
531 if (!task->sc || session->state != ISCSI_STATE_LOGGED_IN) {
532 iscsi_conn_printk(KERN_INFO, conn,
533 "dropping R2T itt %d in recovery.\n",
534 task->itt);
535 return 0;
536 }
537
538 rc = __kfifo_get(tcp_task->r2tpool.queue, (void*)&r2t, sizeof(void*));
539 if (!rc) {
540 iscsi_conn_printk(KERN_ERR, conn, "Could not allocate R2T. "
541 "Target has sent more R2Ts than it "
542 "negotiated for or driver has has leaked.\n");
543 return ISCSI_ERR_PROTO;
544 }
545
546 r2t->exp_statsn = rhdr->statsn;
547 r2t->data_length = be32_to_cpu(rhdr->data_length);
548 if (r2t->data_length == 0) {
549 iscsi_conn_printk(KERN_ERR, conn,
550 "invalid R2T with zero data len\n");
551 __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
552 sizeof(void*));
553 return ISCSI_ERR_DATALEN;
554 }
555
556 if (r2t->data_length > session->max_burst)
Mike Christie0ab1c252009-03-05 14:45:59 -0600557 ISCSI_DBG_TCP(conn, "invalid R2T with data len %u and max "
558 "burst %u. Attempting to execute request.\n",
559 r2t->data_length, session->max_burst);
Mike Christiea081c132008-12-02 00:32:11 -0600560
561 r2t->data_offset = be32_to_cpu(rhdr->data_offset);
562 if (r2t->data_offset + r2t->data_length > scsi_out(task->sc)->length) {
563 iscsi_conn_printk(KERN_ERR, conn,
564 "invalid R2T with data len %u at offset %u "
565 "and total length %d\n", r2t->data_length,
566 r2t->data_offset, scsi_out(task->sc)->length);
567 __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
568 sizeof(void*));
569 return ISCSI_ERR_DATALEN;
570 }
571
572 r2t->ttt = rhdr->ttt; /* no flip */
573 r2t->datasn = 0;
574 r2t->sent = 0;
575
576 tcp_task->exp_datasn = r2tsn + 1;
577 __kfifo_put(tcp_task->r2tqueue, (void*)&r2t, sizeof(void*));
578 conn->r2t_pdus_cnt++;
579
580 iscsi_requeue_task(task);
581 return 0;
582}
583
584/*
585 * Handle incoming reply to DataIn command
586 */
587static int
588iscsi_tcp_process_data_in(struct iscsi_tcp_conn *tcp_conn,
589 struct iscsi_segment *segment)
590{
591 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
592 struct iscsi_hdr *hdr = tcp_conn->in.hdr;
593 int rc;
594
595 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
596 return ISCSI_ERR_DATA_DGST;
597
598 /* check for non-exceptional status */
599 if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
600 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, NULL, 0);
601 if (rc)
602 return rc;
603 }
604
605 iscsi_tcp_hdr_recv_prep(tcp_conn);
606 return 0;
607}
608
609/**
610 * iscsi_tcp_hdr_dissect - process PDU header
611 * @conn: iSCSI connection
612 * @hdr: PDU header
613 *
614 * This function analyzes the header of the PDU received,
615 * and performs several sanity checks. If the PDU is accompanied
616 * by data, the receive buffer is set up to copy the incoming data
617 * to the correct location.
618 */
619static int
620iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
621{
622 int rc = 0, opcode, ahslen;
623 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
624 struct iscsi_task *task;
625
626 /* verify PDU length */
627 tcp_conn->in.datalen = ntoh24(hdr->dlength);
628 if (tcp_conn->in.datalen > conn->max_recv_dlength) {
629 iscsi_conn_printk(KERN_ERR, conn,
630 "iscsi_tcp: datalen %d > %d\n",
631 tcp_conn->in.datalen, conn->max_recv_dlength);
632 return ISCSI_ERR_DATALEN;
633 }
634
635 /* Additional header segments. So far, we don't
636 * process additional headers.
637 */
638 ahslen = hdr->hlength << 2;
639
640 opcode = hdr->opcode & ISCSI_OPCODE_MASK;
641 /* verify itt (itt encoding: age+cid+itt) */
642 rc = iscsi_verify_itt(conn, hdr->itt);
643 if (rc)
644 return rc;
645
Mike Christie0ab1c252009-03-05 14:45:59 -0600646 ISCSI_DBG_TCP(conn, "opcode 0x%x ahslen %d datalen %d\n",
647 opcode, ahslen, tcp_conn->in.datalen);
Mike Christiea081c132008-12-02 00:32:11 -0600648
649 switch(opcode) {
650 case ISCSI_OP_SCSI_DATA_IN:
651 spin_lock(&conn->session->lock);
652 task = iscsi_itt_to_ctask(conn, hdr->itt);
653 if (!task)
654 rc = ISCSI_ERR_BAD_ITT;
655 else
656 rc = iscsi_tcp_data_in(conn, task);
657 if (rc) {
658 spin_unlock(&conn->session->lock);
659 break;
660 }
661
662 if (tcp_conn->in.datalen) {
663 struct iscsi_tcp_task *tcp_task = task->dd_data;
664 struct hash_desc *rx_hash = NULL;
665 struct scsi_data_buffer *sdb = scsi_in(task->sc);
666
667 /*
668 * Setup copy of Data-In into the Scsi_Cmnd
669 * Scatterlist case:
670 * We set up the iscsi_segment to point to the next
671 * scatterlist entry to copy to. As we go along,
672 * we move on to the next scatterlist entry and
673 * update the digest per-entry.
674 */
675 if (conn->datadgst_en &&
676 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
677 rx_hash = tcp_conn->rx_hash;
678
Mike Christie0ab1c252009-03-05 14:45:59 -0600679 ISCSI_DBG_TCP(conn, "iscsi_tcp_begin_data_in( "
680 "offset=%d, datalen=%d)\n",
681 tcp_task->data_offset,
682 tcp_conn->in.datalen);
Mike Christiea081c132008-12-02 00:32:11 -0600683 rc = iscsi_segment_seek_sg(&tcp_conn->in.segment,
684 sdb->table.sgl,
685 sdb->table.nents,
686 tcp_task->data_offset,
687 tcp_conn->in.datalen,
688 iscsi_tcp_process_data_in,
689 rx_hash);
690 spin_unlock(&conn->session->lock);
691 return rc;
692 }
693 rc = __iscsi_complete_pdu(conn, hdr, NULL, 0);
694 spin_unlock(&conn->session->lock);
695 break;
696 case ISCSI_OP_SCSI_CMD_RSP:
697 if (tcp_conn->in.datalen) {
698 iscsi_tcp_data_recv_prep(tcp_conn);
699 return 0;
700 }
701 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
702 break;
703 case ISCSI_OP_R2T:
704 spin_lock(&conn->session->lock);
705 task = iscsi_itt_to_ctask(conn, hdr->itt);
706 if (!task)
707 rc = ISCSI_ERR_BAD_ITT;
708 else if (ahslen)
709 rc = ISCSI_ERR_AHSLEN;
710 else if (task->sc->sc_data_direction == DMA_TO_DEVICE)
711 rc = iscsi_tcp_r2t_rsp(conn, task);
712 else
713 rc = ISCSI_ERR_PROTO;
714 spin_unlock(&conn->session->lock);
715 break;
716 case ISCSI_OP_LOGIN_RSP:
717 case ISCSI_OP_TEXT_RSP:
718 case ISCSI_OP_REJECT:
719 case ISCSI_OP_ASYNC_EVENT:
720 /*
721 * It is possible that we could get a PDU with a buffer larger
722 * than 8K, but there are no targets that currently do this.
723 * For now we fail until we find a vendor that needs it
724 */
725 if (ISCSI_DEF_MAX_RECV_SEG_LEN < tcp_conn->in.datalen) {
726 iscsi_conn_printk(KERN_ERR, conn,
727 "iscsi_tcp: received buffer of "
728 "len %u but conn buffer is only %u "
729 "(opcode %0x)\n",
730 tcp_conn->in.datalen,
731 ISCSI_DEF_MAX_RECV_SEG_LEN, opcode);
732 rc = ISCSI_ERR_PROTO;
733 break;
734 }
735
736 /* If there's data coming in with the response,
737 * receive it to the connection's buffer.
738 */
739 if (tcp_conn->in.datalen) {
740 iscsi_tcp_data_recv_prep(tcp_conn);
741 return 0;
742 }
743 /* fall through */
744 case ISCSI_OP_LOGOUT_RSP:
745 case ISCSI_OP_NOOP_IN:
746 case ISCSI_OP_SCSI_TMFUNC_RSP:
747 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
748 break;
749 default:
750 rc = ISCSI_ERR_BAD_OPCODE;
751 break;
752 }
753
754 if (rc == 0) {
755 /* Anything that comes with data should have
756 * been handled above. */
757 if (tcp_conn->in.datalen)
758 return ISCSI_ERR_PROTO;
759 iscsi_tcp_hdr_recv_prep(tcp_conn);
760 }
761
762 return rc;
763}
764
765/**
766 * iscsi_tcp_hdr_recv_done - process PDU header
767 *
768 * This is the callback invoked when the PDU header has
769 * been received. If the header is followed by additional
770 * header segments, we go back for more data.
771 */
772static int
773iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
774 struct iscsi_segment *segment)
775{
776 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
777 struct iscsi_hdr *hdr;
778
779 /* Check if there are additional header segments
780 * *prior* to computing the digest, because we
781 * may need to go back to the caller for more.
782 */
783 hdr = (struct iscsi_hdr *) tcp_conn->in.hdr_buf;
784 if (segment->copied == sizeof(struct iscsi_hdr) && hdr->hlength) {
785 /* Bump the header length - the caller will
786 * just loop around and get the AHS for us, and
787 * call again. */
788 unsigned int ahslen = hdr->hlength << 2;
789
790 /* Make sure we don't overflow */
791 if (sizeof(*hdr) + ahslen > sizeof(tcp_conn->in.hdr_buf))
792 return ISCSI_ERR_AHSLEN;
793
794 segment->total_size += ahslen;
795 segment->size += ahslen;
796 return 0;
797 }
798
799 /* We're done processing the header. See if we're doing
800 * header digests; if so, set up the recv_digest buffer
801 * and go back for more. */
Mike Christie6df19a72008-12-02 00:32:16 -0600802 if (conn->hdrdgst_en &&
803 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD)) {
Mike Christiea081c132008-12-02 00:32:11 -0600804 if (segment->digest_len == 0) {
805 /*
806 * Even if we offload the digest processing we
807 * splice it in so we can increment the skb/segment
808 * counters in preparation for the data segment.
809 */
810 iscsi_tcp_segment_splice_digest(segment,
811 segment->recv_digest);
812 return 0;
813 }
814
Mike Christie6df19a72008-12-02 00:32:16 -0600815 iscsi_tcp_dgst_header(tcp_conn->rx_hash, hdr,
816 segment->total_copied - ISCSI_DIGEST_SIZE,
817 segment->digest);
Mike Christiea081c132008-12-02 00:32:11 -0600818
Mike Christie6df19a72008-12-02 00:32:16 -0600819 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
820 return ISCSI_ERR_HDR_DGST;
Mike Christiea081c132008-12-02 00:32:11 -0600821 }
822
823 tcp_conn->in.hdr = hdr;
824 return iscsi_tcp_hdr_dissect(conn, hdr);
825}
826
827/**
828 * iscsi_tcp_recv_segment_is_hdr - tests if we are reading in a header
829 * @tcp_conn: iscsi tcp conn
830 *
831 * returns non zero if we are currently processing or setup to process
832 * a header.
833 */
834inline int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn)
835{
836 return tcp_conn->in.segment.done == iscsi_tcp_hdr_recv_done;
837}
838EXPORT_SYMBOL_GPL(iscsi_tcp_recv_segment_is_hdr);
839
840/**
841 * iscsi_tcp_recv_skb - Process skb
842 * @conn: iscsi connection
843 * @skb: network buffer with header and/or data segment
844 * @offset: offset in skb
845 * @offload: bool indicating if transfer was offloaded
846 *
847 * Will return status of transfer in status. And will return
848 * number of bytes copied.
849 */
850int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
851 unsigned int offset, bool offloaded, int *status)
852{
853 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
854 struct iscsi_segment *segment = &tcp_conn->in.segment;
855 struct skb_seq_state seq;
856 unsigned int consumed = 0;
857 int rc = 0;
858
Mike Christie0ab1c252009-03-05 14:45:59 -0600859 ISCSI_DBG_TCP(conn, "in %d bytes\n", skb->len - offset);
Mike Christiea081c132008-12-02 00:32:11 -0600860
861 if (unlikely(conn->suspend_rx)) {
Mike Christie0ab1c252009-03-05 14:45:59 -0600862 ISCSI_DBG_TCP(conn, "Rx suspended!\n");
Mike Christiea081c132008-12-02 00:32:11 -0600863 *status = ISCSI_TCP_SUSPENDED;
864 return 0;
865 }
866
867 if (offloaded) {
868 segment->total_copied = segment->total_size;
869 goto segment_done;
870 }
871
872 skb_prepare_seq_read(skb, offset, skb->len, &seq);
873 while (1) {
874 unsigned int avail;
875 const u8 *ptr;
876
877 avail = skb_seq_read(consumed, &ptr, &seq);
878 if (avail == 0) {
Mike Christie0ab1c252009-03-05 14:45:59 -0600879 ISCSI_DBG_TCP(conn, "no more data avail. Consumed %d\n",
880 consumed);
Mike Christiea081c132008-12-02 00:32:11 -0600881 *status = ISCSI_TCP_SKB_DONE;
882 skb_abort_seq_read(&seq);
883 goto skb_done;
884 }
885 BUG_ON(segment->copied >= segment->size);
886
Mike Christie0ab1c252009-03-05 14:45:59 -0600887 ISCSI_DBG_TCP(conn, "skb %p ptr=%p avail=%u\n", skb, ptr,
888 avail);
Mike Christiea081c132008-12-02 00:32:11 -0600889 rc = iscsi_tcp_segment_recv(tcp_conn, segment, ptr, avail);
890 BUG_ON(rc == 0);
891 consumed += rc;
892
893 if (segment->total_copied >= segment->total_size) {
894 skb_abort_seq_read(&seq);
895 goto segment_done;
896 }
897 }
898
899segment_done:
900 *status = ISCSI_TCP_SEGMENT_DONE;
Mike Christie0ab1c252009-03-05 14:45:59 -0600901 ISCSI_DBG_TCP(conn, "segment done\n");
Mike Christiea081c132008-12-02 00:32:11 -0600902 rc = segment->done(tcp_conn, segment);
903 if (rc != 0) {
904 *status = ISCSI_TCP_CONN_ERR;
Mike Christie0ab1c252009-03-05 14:45:59 -0600905 ISCSI_DBG_TCP(conn, "Error receiving PDU, errno=%d\n", rc);
Mike Christiea081c132008-12-02 00:32:11 -0600906 iscsi_conn_failure(conn, rc);
907 return 0;
908 }
909 /* The done() functions sets up the next segment. */
910
911skb_done:
912 conn->rxdata_octets += consumed;
913 return consumed;
914}
915EXPORT_SYMBOL_GPL(iscsi_tcp_recv_skb);
916
917/**
918 * iscsi_tcp_task_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
919 * @conn: iscsi connection
920 * @task: scsi command task
921 * @sc: scsi command
922 */
923int iscsi_tcp_task_init(struct iscsi_task *task)
924{
925 struct iscsi_tcp_task *tcp_task = task->dd_data;
926 struct iscsi_conn *conn = task->conn;
927 struct scsi_cmnd *sc = task->sc;
928 int err;
929
930 if (!sc) {
931 /*
932 * mgmt tasks do not have a scatterlist since they come
933 * in from the iscsi interface.
934 */
Mike Christie0ab1c252009-03-05 14:45:59 -0600935 ISCSI_DBG_TCP(conn, "mtask deq [itt 0x%x]\n", task->itt);
Mike Christiea081c132008-12-02 00:32:11 -0600936
937 return conn->session->tt->init_pdu(task, 0, task->data_count);
938 }
939
940 BUG_ON(__kfifo_len(tcp_task->r2tqueue));
941 tcp_task->exp_datasn = 0;
942
943 /* Prepare PDU, optionally w/ immediate data */
Mike Christie0ab1c252009-03-05 14:45:59 -0600944 ISCSI_DBG_TCP(conn, "task deq [itt 0x%x imm %d unsol %d]\n",
945 task->itt, task->imm_count, task->unsol_r2t.data_length);
Mike Christiea081c132008-12-02 00:32:11 -0600946
947 err = conn->session->tt->init_pdu(task, 0, task->imm_count);
948 if (err)
949 return err;
950 task->imm_count = 0;
951 return 0;
952}
953EXPORT_SYMBOL_GPL(iscsi_tcp_task_init);
954
955static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
956{
957 struct iscsi_session *session = task->conn->session;
958 struct iscsi_tcp_task *tcp_task = task->dd_data;
959 struct iscsi_r2t_info *r2t = NULL;
960
961 if (iscsi_task_has_unsol_data(task))
962 r2t = &task->unsol_r2t;
963 else {
964 spin_lock_bh(&session->lock);
965 if (tcp_task->r2t) {
966 r2t = tcp_task->r2t;
967 /* Continue with this R2T? */
968 if (r2t->data_length <= r2t->sent) {
Mike Christie0ab1c252009-03-05 14:45:59 -0600969 ISCSI_DBG_TCP(task->conn,
970 " done with r2t %p\n", r2t);
Mike Christiea081c132008-12-02 00:32:11 -0600971 __kfifo_put(tcp_task->r2tpool.queue,
972 (void *)&tcp_task->r2t,
973 sizeof(void *));
974 tcp_task->r2t = r2t = NULL;
975 }
976 }
977
978 if (r2t == NULL) {
979 __kfifo_get(tcp_task->r2tqueue,
980 (void *)&tcp_task->r2t, sizeof(void *));
981 r2t = tcp_task->r2t;
982 }
983 spin_unlock_bh(&session->lock);
984 }
985
986 return r2t;
987}
988
989/**
990 * iscsi_tcp_task_xmit - xmit normal PDU task
991 * @task: iscsi command task
992 *
993 * We're expected to return 0 when everything was transmitted succesfully,
994 * -EAGAIN if there's still data in the queue, or != 0 for any other kind
995 * of error.
996 */
997int iscsi_tcp_task_xmit(struct iscsi_task *task)
998{
999 struct iscsi_conn *conn = task->conn;
1000 struct iscsi_session *session = conn->session;
1001 struct iscsi_r2t_info *r2t;
1002 int rc = 0;
1003
1004flush:
1005 /* Flush any pending data first. */
1006 rc = session->tt->xmit_pdu(task);
1007 if (rc < 0)
1008 return rc;
1009
1010 /* mgmt command */
1011 if (!task->sc) {
1012 if (task->hdr->itt == RESERVED_ITT)
1013 iscsi_put_task(task);
1014 return 0;
1015 }
1016
1017 /* Are we done already? */
1018 if (task->sc->sc_data_direction != DMA_TO_DEVICE)
1019 return 0;
1020
1021 r2t = iscsi_tcp_get_curr_r2t(task);
1022 if (r2t == NULL) {
1023 /* Waiting for more R2Ts to arrive. */
Mike Christie0ab1c252009-03-05 14:45:59 -06001024 ISCSI_DBG_TCP(conn, "no R2Ts yet\n");
Mike Christiea081c132008-12-02 00:32:11 -06001025 return 0;
1026 }
1027
Mike Christie2ff79d52008-12-02 00:32:14 -06001028 rc = conn->session->tt->alloc_pdu(task, ISCSI_OP_SCSI_DATA_OUT);
Mike Christiea081c132008-12-02 00:32:11 -06001029 if (rc)
1030 return rc;
1031 iscsi_prep_data_out_pdu(task, r2t, (struct iscsi_data *) task->hdr);
1032
Mike Christie0ab1c252009-03-05 14:45:59 -06001033 ISCSI_DBG_TCP(conn, "sol dout %p [dsn %d itt 0x%x doff %d dlen %d]\n",
1034 r2t, r2t->datasn - 1, task->hdr->itt,
1035 r2t->data_offset + r2t->sent, r2t->data_count);
Mike Christiea081c132008-12-02 00:32:11 -06001036
1037 rc = conn->session->tt->init_pdu(task, r2t->data_offset + r2t->sent,
1038 r2t->data_count);
1039 if (rc)
1040 return rc;
1041 r2t->sent += r2t->data_count;
1042 goto flush;
1043}
1044EXPORT_SYMBOL_GPL(iscsi_tcp_task_xmit);
1045
1046struct iscsi_cls_conn *
1047iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
1048 uint32_t conn_idx)
1049
1050{
1051 struct iscsi_conn *conn;
1052 struct iscsi_cls_conn *cls_conn;
1053 struct iscsi_tcp_conn *tcp_conn;
1054
1055 cls_conn = iscsi_conn_setup(cls_session, sizeof(*tcp_conn), conn_idx);
1056 if (!cls_conn)
1057 return NULL;
1058 conn = cls_conn->dd_data;
1059 /*
1060 * due to strange issues with iser these are not set
1061 * in iscsi_conn_setup
1062 */
1063 conn->max_recv_dlength = ISCSI_DEF_MAX_RECV_SEG_LEN;
1064
1065 tcp_conn = conn->dd_data;
1066 tcp_conn->iscsi_conn = conn;
1067
1068 tcp_conn->dd_data = kzalloc(dd_data_size, GFP_KERNEL);
1069 if (!tcp_conn->dd_data) {
1070 iscsi_conn_teardown(cls_conn);
1071 return NULL;
1072 }
1073 return cls_conn;
1074}
1075EXPORT_SYMBOL_GPL(iscsi_tcp_conn_setup);
1076
1077void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn)
1078{
1079 struct iscsi_conn *conn = cls_conn->dd_data;
1080 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1081
1082 kfree(tcp_conn->dd_data);
1083 iscsi_conn_teardown(cls_conn);
1084}
1085EXPORT_SYMBOL_GPL(iscsi_tcp_conn_teardown);
1086
1087int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session)
1088{
1089 int i;
1090 int cmd_i;
1091
1092 /*
1093 * initialize per-task: R2T pool and xmit queue
1094 */
1095 for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
1096 struct iscsi_task *task = session->cmds[cmd_i];
1097 struct iscsi_tcp_task *tcp_task = task->dd_data;
1098
1099 /*
1100 * pre-allocated x2 as much r2ts to handle race when
1101 * target acks DataOut faster than we data_xmit() queues
1102 * could replenish r2tqueue.
1103 */
1104
1105 /* R2T pool */
1106 if (iscsi_pool_init(&tcp_task->r2tpool,
1107 session->max_r2t * 2, NULL,
1108 sizeof(struct iscsi_r2t_info))) {
1109 goto r2t_alloc_fail;
1110 }
1111
1112 /* R2T xmit queue */
1113 tcp_task->r2tqueue = kfifo_alloc(
1114 session->max_r2t * 4 * sizeof(void*), GFP_KERNEL, NULL);
1115 if (tcp_task->r2tqueue == ERR_PTR(-ENOMEM)) {
1116 iscsi_pool_free(&tcp_task->r2tpool);
1117 goto r2t_alloc_fail;
1118 }
1119 }
1120
1121 return 0;
1122
1123r2t_alloc_fail:
1124 for (i = 0; i < cmd_i; i++) {
1125 struct iscsi_task *task = session->cmds[i];
1126 struct iscsi_tcp_task *tcp_task = task->dd_data;
1127
1128 kfifo_free(tcp_task->r2tqueue);
1129 iscsi_pool_free(&tcp_task->r2tpool);
1130 }
1131 return -ENOMEM;
1132}
1133EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_alloc);
1134
1135void iscsi_tcp_r2tpool_free(struct iscsi_session *session)
1136{
1137 int i;
1138
1139 for (i = 0; i < session->cmds_max; i++) {
1140 struct iscsi_task *task = session->cmds[i];
1141 struct iscsi_tcp_task *tcp_task = task->dd_data;
1142
1143 kfifo_free(tcp_task->r2tqueue);
1144 iscsi_pool_free(&tcp_task->r2tpool);
1145 }
1146}
1147EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_free);
1148
1149void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
1150 struct iscsi_stats *stats)
1151{
1152 struct iscsi_conn *conn = cls_conn->dd_data;
1153
1154 stats->txdata_octets = conn->txdata_octets;
1155 stats->rxdata_octets = conn->rxdata_octets;
1156 stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
1157 stats->dataout_pdus = conn->dataout_pdus_cnt;
1158 stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
1159 stats->datain_pdus = conn->datain_pdus_cnt;
1160 stats->r2t_pdus = conn->r2t_pdus_cnt;
1161 stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
1162 stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
1163}
1164EXPORT_SYMBOL_GPL(iscsi_tcp_conn_get_stats);