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 <linux/crc32c.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->crcp = 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 	unsigned int pad;
195 
196 	ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "copied %u %u size %u %s\n",
197 		      segment->copied, copied, segment->size,
198 		      recv ? "recv" : "xmit");
199 	if (segment->crcp && copied) {
200 		if (segment->data) {
201 			*segment->crcp = crc32c(*segment->crcp,
202 						segment->data + segment->copied,
203 						copied);
204 		} else {
205 			const void *data;
206 
207 			data = kmap_local_page(sg_page(segment->sg));
208 			*segment->crcp = crc32c(*segment->crcp,
209 						data + segment->copied +
210 						segment->sg_offset +
211 						segment->sg->offset,
212 						copied);
213 			kunmap_local(data);
214 		}
215 	}
216 
217 	segment->copied += copied;
218 	if (segment->copied < segment->size) {
219 		iscsi_tcp_segment_map(segment, recv);
220 		return 0;
221 	}
222 
223 	segment->total_copied += segment->copied;
224 	segment->copied = 0;
225 	segment->size = 0;
226 
227 	/* Unmap the current scatterlist page, if there is one. */
228 	iscsi_tcp_segment_unmap(segment);
229 
230 	/* Do we have more scatterlist entries? */
231 	ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "total copied %u total size %u\n",
232 		      segment->total_copied, segment->total_size);
233 	if (segment->total_copied < segment->total_size) {
234 		/* Proceed to the next entry in the scatterlist. */
235 		iscsi_tcp_segment_init_sg(segment, sg_next(segment->sg),
236 					  0);
237 		iscsi_tcp_segment_map(segment, recv);
238 		BUG_ON(segment->size == 0);
239 		return 0;
240 	}
241 
242 	/* Do we need to handle padding? */
243 	if (!(tcp_conn->iscsi_conn->session->tt->caps & CAP_PADDING_OFFLOAD)) {
244 		pad = iscsi_padding(segment->total_copied);
245 		if (pad != 0) {
246 			ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
247 				      "consume %d pad bytes\n", pad);
248 			segment->total_size += pad;
249 			segment->size = pad;
250 			segment->data = segment->padbuf;
251 			return 0;
252 		}
253 	}
254 
255 	/*
256 	 * Set us up for transferring the data digest. hdr digest
257 	 * is completely handled in hdr done function.
258 	 */
259 	if (segment->crcp) {
260 		put_unaligned_le32(~*segment->crcp, segment->digest);
261 		iscsi_tcp_segment_splice_digest(segment,
262 				 recv ? segment->recv_digest : segment->digest);
263 		return 0;
264 	}
265 
266 	return 1;
267 }
268 EXPORT_SYMBOL_GPL(iscsi_tcp_segment_done);
269 
270 /**
271  * iscsi_tcp_segment_recv - copy data to segment
272  * @tcp_conn: the iSCSI TCP connection
273  * @segment: the buffer to copy to
274  * @ptr: data pointer
275  * @len: amount of data available
276  *
277  * This function copies up to @len bytes to the
278  * given buffer, and returns the number of bytes
279  * consumed, which can actually be less than @len.
280  *
281  * If CRC is enabled, the function will update the CRC while copying.
282  * Combining these two operations doesn't buy us a lot (yet),
283  * but in the future we could implement combined copy+crc,
284  * just way we do for network layer checksums.
285  */
286 static int
287 iscsi_tcp_segment_recv(struct iscsi_tcp_conn *tcp_conn,
288 		       struct iscsi_segment *segment, const void *ptr,
289 		       unsigned int len)
290 {
291 	unsigned int copy = 0, copied = 0;
292 
293 	while (!iscsi_tcp_segment_done(tcp_conn, segment, 1, copy)) {
294 		if (copied == len) {
295 			ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
296 				      "copied %d bytes\n", len);
297 			break;
298 		}
299 
300 		copy = min(len - copied, segment->size - segment->copied);
301 		ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "copying %d\n", copy);
302 		memcpy(segment->data + segment->copied, ptr + copied, copy);
303 		copied += copy;
304 	}
305 	return copied;
306 }
307 
308 inline void
309 iscsi_tcp_dgst_header(const void *hdr, size_t hdrlen,
310 		      unsigned char digest[ISCSI_DIGEST_SIZE])
311 {
312 	put_unaligned_le32(~crc32c(~0, hdr, hdrlen), digest);
313 }
314 EXPORT_SYMBOL_GPL(iscsi_tcp_dgst_header);
315 
316 static inline int
317 iscsi_tcp_dgst_verify(struct iscsi_tcp_conn *tcp_conn,
318 		      struct iscsi_segment *segment)
319 {
320 	if (!segment->digest_len)
321 		return 1;
322 
323 	if (memcmp(segment->recv_digest, segment->digest,
324 		   segment->digest_len)) {
325 		ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "digest mismatch\n");
326 		return 0;
327 	}
328 
329 	return 1;
330 }
331 
332 /*
333  * Helper function to set up segment buffer
334  */
335 static inline void
336 __iscsi_segment_init(struct iscsi_segment *segment, size_t size,
337 		     iscsi_segment_done_fn_t *done, u32 *crcp)
338 {
339 	memset(segment, 0, sizeof(*segment));
340 	segment->total_size = size;
341 	segment->done = done;
342 
343 	if (crcp) {
344 		segment->crcp = crcp;
345 		*crcp = ~0;
346 	}
347 }
348 
349 inline void
350 iscsi_segment_init_linear(struct iscsi_segment *segment, void *data,
351 			  size_t size, iscsi_segment_done_fn_t *done, u32 *crcp)
352 {
353 	__iscsi_segment_init(segment, size, done, crcp);
354 	segment->data = data;
355 	segment->size = size;
356 }
357 EXPORT_SYMBOL_GPL(iscsi_segment_init_linear);
358 
359 inline int
360 iscsi_segment_seek_sg(struct iscsi_segment *segment,
361 		      struct scatterlist *sg_list, unsigned int sg_count,
362 		      unsigned int offset, size_t size,
363 		      iscsi_segment_done_fn_t *done, u32 *crcp)
364 {
365 	struct scatterlist *sg;
366 	unsigned int i;
367 
368 	__iscsi_segment_init(segment, size, done, crcp);
369 	for_each_sg(sg_list, sg, sg_count, i) {
370 		if (offset < sg->length) {
371 			iscsi_tcp_segment_init_sg(segment, sg, offset);
372 			return 0;
373 		}
374 		offset -= sg->length;
375 	}
376 
377 	return ISCSI_ERR_DATA_OFFSET;
378 }
379 EXPORT_SYMBOL_GPL(iscsi_segment_seek_sg);
380 
381 /**
382  * iscsi_tcp_hdr_recv_prep - prep segment for hdr reception
383  * @tcp_conn: iscsi connection to prep for
384  *
385  * This function always passes NULL for the crcp argument, because when this
386  * function is called we do not yet know the final size of the header and want
387  * to delay the digest processing until we know that.
388  */
389 void iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn)
390 {
391 	ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
392 		      "(%s)\n", tcp_conn->iscsi_conn->hdrdgst_en ?
393 		      "digest enabled" : "digest disabled");
394 	iscsi_segment_init_linear(&tcp_conn->in.segment,
395 				tcp_conn->in.hdr_buf, sizeof(struct iscsi_hdr),
396 				iscsi_tcp_hdr_recv_done, NULL);
397 }
398 EXPORT_SYMBOL_GPL(iscsi_tcp_hdr_recv_prep);
399 
400 /*
401  * Handle incoming reply to any other type of command
402  */
403 static int
404 iscsi_tcp_data_recv_done(struct iscsi_tcp_conn *tcp_conn,
405 			 struct iscsi_segment *segment)
406 {
407 	struct iscsi_conn *conn = tcp_conn->iscsi_conn;
408 	int rc = 0;
409 
410 	if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
411 		return ISCSI_ERR_DATA_DGST;
412 
413 	rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr,
414 			conn->data, tcp_conn->in.datalen);
415 	if (rc)
416 		return rc;
417 
418 	iscsi_tcp_hdr_recv_prep(tcp_conn);
419 	return 0;
420 }
421 
422 static void
423 iscsi_tcp_data_recv_prep(struct iscsi_tcp_conn *tcp_conn)
424 {
425 	struct iscsi_conn *conn = tcp_conn->iscsi_conn;
426 	u32 *rx_crcp = NULL;
427 
428 	if (conn->datadgst_en &&
429 	    !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
430 		rx_crcp = tcp_conn->rx_crcp;
431 
432 	iscsi_segment_init_linear(&tcp_conn->in.segment,
433 				conn->data, tcp_conn->in.datalen,
434 				iscsi_tcp_data_recv_done, rx_crcp);
435 }
436 
437 /**
438  * iscsi_tcp_cleanup_task - free tcp_task resources
439  * @task: iscsi task
440  *
441  * must be called with session back_lock
442  */
443 void iscsi_tcp_cleanup_task(struct iscsi_task *task)
444 {
445 	struct iscsi_tcp_task *tcp_task = task->dd_data;
446 	struct iscsi_r2t_info *r2t;
447 
448 	/* nothing to do for mgmt */
449 	if (!task->sc)
450 		return;
451 
452 	spin_lock_bh(&tcp_task->queue2pool);
453 	/* flush task's r2t queues */
454 	while (kfifo_out(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*))) {
455 		kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
456 			    sizeof(void*));
457 		ISCSI_DBG_TCP(task->conn, "pending r2t dropped\n");
458 	}
459 
460 	r2t = tcp_task->r2t;
461 	if (r2t != NULL) {
462 		kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
463 			    sizeof(void*));
464 		tcp_task->r2t = NULL;
465 	}
466 	spin_unlock_bh(&tcp_task->queue2pool);
467 }
468 EXPORT_SYMBOL_GPL(iscsi_tcp_cleanup_task);
469 
470 /**
471  * iscsi_tcp_data_in - SCSI Data-In Response processing
472  * @conn: iscsi connection
473  * @task: scsi command task
474  */
475 static int iscsi_tcp_data_in(struct iscsi_conn *conn, struct iscsi_task *task)
476 {
477 	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
478 	struct iscsi_tcp_task *tcp_task = task->dd_data;
479 	struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)tcp_conn->in.hdr;
480 	int datasn = be32_to_cpu(rhdr->datasn);
481 	unsigned total_in_length = task->sc->sdb.length;
482 
483 	/*
484 	 * lib iscsi will update this in the completion handling if there
485 	 * is status.
486 	 */
487 	if (!(rhdr->flags & ISCSI_FLAG_DATA_STATUS))
488 		iscsi_update_cmdsn(conn->session, (struct iscsi_nopin*)rhdr);
489 
490 	if (tcp_conn->in.datalen == 0)
491 		return 0;
492 
493 	if (tcp_task->exp_datasn != datasn) {
494 		ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->datasn(%d)"
495 			      "\n", tcp_task->exp_datasn, datasn);
496 		return ISCSI_ERR_DATASN;
497 	}
498 
499 	tcp_task->exp_datasn++;
500 
501 	tcp_task->data_offset = be32_to_cpu(rhdr->offset);
502 	if (tcp_task->data_offset + tcp_conn->in.datalen > total_in_length) {
503 		ISCSI_DBG_TCP(conn, "data_offset(%d) + data_len(%d) > "
504 			      "total_length_in(%d)\n", tcp_task->data_offset,
505 			      tcp_conn->in.datalen, total_in_length);
506 		return ISCSI_ERR_DATA_OFFSET;
507 	}
508 
509 	conn->datain_pdus_cnt++;
510 	return 0;
511 }
512 
513 /**
514  * iscsi_tcp_r2t_rsp - iSCSI R2T Response processing
515  * @conn: iscsi connection
516  * @hdr: PDU header
517  */
518 static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
519 {
520 	struct iscsi_session *session = conn->session;
521 	struct iscsi_tcp_task *tcp_task;
522 	struct iscsi_tcp_conn *tcp_conn;
523 	struct iscsi_r2t_rsp *rhdr;
524 	struct iscsi_r2t_info *r2t;
525 	struct iscsi_task *task;
526 	u32 data_length;
527 	u32 data_offset;
528 	int r2tsn;
529 	int rc;
530 
531 	spin_lock(&session->back_lock);
532 	task = iscsi_itt_to_ctask(conn, hdr->itt);
533 	if (!task) {
534 		spin_unlock(&session->back_lock);
535 		return ISCSI_ERR_BAD_ITT;
536 	} else if (task->sc->sc_data_direction != DMA_TO_DEVICE) {
537 		spin_unlock(&session->back_lock);
538 		return ISCSI_ERR_PROTO;
539 	}
540 	/*
541 	 * A bad target might complete the cmd before we have handled R2Ts
542 	 * so get a ref to the task that will be dropped in the xmit path.
543 	 */
544 	if (task->state != ISCSI_TASK_RUNNING) {
545 		spin_unlock(&session->back_lock);
546 		/* Let the path that got the early rsp complete it */
547 		return 0;
548 	}
549 	task->last_xfer = jiffies;
550 	if (!iscsi_get_task(task)) {
551 		spin_unlock(&session->back_lock);
552 		/* Let the path that got the early rsp complete it */
553 		return 0;
554 	}
555 
556 	tcp_conn = conn->dd_data;
557 	rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr;
558 	/* fill-in new R2T associated with the task */
559 	iscsi_update_cmdsn(session, (struct iscsi_nopin *)rhdr);
560 	spin_unlock(&session->back_lock);
561 
562 	if (tcp_conn->in.datalen) {
563 		iscsi_conn_printk(KERN_ERR, conn,
564 				  "invalid R2t with datalen %d\n",
565 				  tcp_conn->in.datalen);
566 		rc = ISCSI_ERR_DATALEN;
567 		goto put_task;
568 	}
569 
570 	tcp_task = task->dd_data;
571 	r2tsn = be32_to_cpu(rhdr->r2tsn);
572 	if (tcp_task->exp_datasn != r2tsn){
573 		ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->r2tsn(%d)\n",
574 			      tcp_task->exp_datasn, r2tsn);
575 		rc = ISCSI_ERR_R2TSN;
576 		goto put_task;
577 	}
578 
579 	if (session->state != ISCSI_STATE_LOGGED_IN) {
580 		iscsi_conn_printk(KERN_INFO, conn,
581 				  "dropping R2T itt %d in recovery.\n",
582 				  task->itt);
583 		rc = 0;
584 		goto put_task;
585 	}
586 
587 	data_length = be32_to_cpu(rhdr->data_length);
588 	if (data_length == 0) {
589 		iscsi_conn_printk(KERN_ERR, conn,
590 				  "invalid R2T with zero data len\n");
591 		rc = ISCSI_ERR_DATALEN;
592 		goto put_task;
593 	}
594 
595 	if (data_length > session->max_burst)
596 		ISCSI_DBG_TCP(conn, "invalid R2T with data len %u and max "
597 			      "burst %u. Attempting to execute request.\n",
598 			      data_length, session->max_burst);
599 
600 	data_offset = be32_to_cpu(rhdr->data_offset);
601 	if (data_offset + data_length > task->sc->sdb.length) {
602 		iscsi_conn_printk(KERN_ERR, conn,
603 				  "invalid R2T with data len %u at offset %u "
604 				  "and total length %d\n", data_length,
605 				  data_offset, task->sc->sdb.length);
606 		rc = ISCSI_ERR_DATALEN;
607 		goto put_task;
608 	}
609 
610 	spin_lock(&tcp_task->pool2queue);
611 	rc = kfifo_out(&tcp_task->r2tpool.queue, (void *)&r2t, sizeof(void *));
612 	if (!rc) {
613 		iscsi_conn_printk(KERN_ERR, conn, "Could not allocate R2T. "
614 				  "Target has sent more R2Ts than it "
615 				  "negotiated for or driver has leaked.\n");
616 		spin_unlock(&tcp_task->pool2queue);
617 		rc = ISCSI_ERR_PROTO;
618 		goto put_task;
619 	}
620 
621 	r2t->exp_statsn = rhdr->statsn;
622 	r2t->data_length = data_length;
623 	r2t->data_offset = data_offset;
624 
625 	r2t->ttt = rhdr->ttt; /* no flip */
626 	r2t->datasn = 0;
627 	r2t->sent = 0;
628 
629 	tcp_task->exp_datasn = r2tsn + 1;
630 	kfifo_in(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*));
631 	conn->r2t_pdus_cnt++;
632 	spin_unlock(&tcp_task->pool2queue);
633 
634 	iscsi_requeue_task(task);
635 	return 0;
636 
637 put_task:
638 	iscsi_put_task(task);
639 	return rc;
640 }
641 
642 /*
643  * Handle incoming reply to DataIn command
644  */
645 static int
646 iscsi_tcp_process_data_in(struct iscsi_tcp_conn *tcp_conn,
647 			  struct iscsi_segment *segment)
648 {
649 	struct iscsi_conn *conn = tcp_conn->iscsi_conn;
650 	struct iscsi_hdr *hdr = tcp_conn->in.hdr;
651 	int rc;
652 
653 	if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
654 		return ISCSI_ERR_DATA_DGST;
655 
656 	/* check for non-exceptional status */
657 	if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
658 		rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, NULL, 0);
659 		if (rc)
660 			return rc;
661 	}
662 
663 	iscsi_tcp_hdr_recv_prep(tcp_conn);
664 	return 0;
665 }
666 
667 /**
668  * iscsi_tcp_hdr_dissect - process PDU header
669  * @conn: iSCSI connection
670  * @hdr: PDU header
671  *
672  * This function analyzes the header of the PDU received,
673  * and performs several sanity checks. If the PDU is accompanied
674  * by data, the receive buffer is set up to copy the incoming data
675  * to the correct location.
676  */
677 static int
678 iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
679 {
680 	int rc = 0, opcode, ahslen;
681 	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
682 	struct iscsi_task *task;
683 
684 	/* verify PDU length */
685 	tcp_conn->in.datalen = ntoh24(hdr->dlength);
686 	if (tcp_conn->in.datalen > conn->max_recv_dlength) {
687 		iscsi_conn_printk(KERN_ERR, conn,
688 				  "iscsi_tcp: datalen %d > %d\n",
689 				  tcp_conn->in.datalen, conn->max_recv_dlength);
690 		return ISCSI_ERR_DATALEN;
691 	}
692 
693 	/* Additional header segments. So far, we don't
694 	 * process additional headers.
695 	 */
696 	ahslen = hdr->hlength << 2;
697 
698 	opcode = hdr->opcode & ISCSI_OPCODE_MASK;
699 	/* verify itt (itt encoding: age+cid+itt) */
700 	rc = iscsi_verify_itt(conn, hdr->itt);
701 	if (rc)
702 		return rc;
703 
704 	ISCSI_DBG_TCP(conn, "opcode 0x%x ahslen %d datalen %d\n",
705 		      opcode, ahslen, tcp_conn->in.datalen);
706 
707 	switch(opcode) {
708 	case ISCSI_OP_SCSI_DATA_IN:
709 		spin_lock(&conn->session->back_lock);
710 		task = iscsi_itt_to_ctask(conn, hdr->itt);
711 		if (!task)
712 			rc = ISCSI_ERR_BAD_ITT;
713 		else
714 			rc = iscsi_tcp_data_in(conn, task);
715 		if (rc) {
716 			spin_unlock(&conn->session->back_lock);
717 			break;
718 		}
719 
720 		if (tcp_conn->in.datalen) {
721 			struct iscsi_tcp_task *tcp_task = task->dd_data;
722 			u32 *rx_crcp = NULL;
723 			struct scsi_data_buffer *sdb = &task->sc->sdb;
724 
725 			/*
726 			 * Setup copy of Data-In into the struct scsi_cmnd
727 			 * Scatterlist case:
728 			 * We set up the iscsi_segment to point to the next
729 			 * scatterlist entry to copy to. As we go along,
730 			 * we move on to the next scatterlist entry and
731 			 * update the digest per-entry.
732 			 */
733 			if (conn->datadgst_en &&
734 			    !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
735 				rx_crcp = tcp_conn->rx_crcp;
736 
737 			ISCSI_DBG_TCP(conn, "iscsi_tcp_begin_data_in( "
738 				     "offset=%d, datalen=%d)\n",
739 				      tcp_task->data_offset,
740 				      tcp_conn->in.datalen);
741 			task->last_xfer = jiffies;
742 			rc = iscsi_segment_seek_sg(&tcp_conn->in.segment,
743 						   sdb->table.sgl,
744 						   sdb->table.nents,
745 						   tcp_task->data_offset,
746 						   tcp_conn->in.datalen,
747 						   iscsi_tcp_process_data_in,
748 						   rx_crcp);
749 			spin_unlock(&conn->session->back_lock);
750 			return rc;
751 		}
752 		rc = __iscsi_complete_pdu(conn, hdr, NULL, 0);
753 		spin_unlock(&conn->session->back_lock);
754 		break;
755 	case ISCSI_OP_SCSI_CMD_RSP:
756 		if (tcp_conn->in.datalen) {
757 			iscsi_tcp_data_recv_prep(tcp_conn);
758 			return 0;
759 		}
760 		rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
761 		break;
762 	case ISCSI_OP_R2T:
763 		if (ahslen) {
764 			rc = ISCSI_ERR_AHSLEN;
765 			break;
766 		}
767 		rc = iscsi_tcp_r2t_rsp(conn, hdr);
768 		break;
769 	case ISCSI_OP_LOGIN_RSP:
770 	case ISCSI_OP_TEXT_RSP:
771 	case ISCSI_OP_REJECT:
772 	case ISCSI_OP_ASYNC_EVENT:
773 		/*
774 		 * It is possible that we could get a PDU with a buffer larger
775 		 * than 8K, but there are no targets that currently do this.
776 		 * For now we fail until we find a vendor that needs it
777 		 */
778 		if (ISCSI_DEF_MAX_RECV_SEG_LEN < tcp_conn->in.datalen) {
779 			iscsi_conn_printk(KERN_ERR, conn,
780 					  "iscsi_tcp: received buffer of "
781 					  "len %u but conn buffer is only %u "
782 					  "(opcode %0x)\n",
783 					  tcp_conn->in.datalen,
784 					  ISCSI_DEF_MAX_RECV_SEG_LEN, opcode);
785 			rc = ISCSI_ERR_PROTO;
786 			break;
787 		}
788 
789 		/* If there's data coming in with the response,
790 		 * receive it to the connection's buffer.
791 		 */
792 		if (tcp_conn->in.datalen) {
793 			iscsi_tcp_data_recv_prep(tcp_conn);
794 			return 0;
795 		}
796 		fallthrough;
797 	case ISCSI_OP_LOGOUT_RSP:
798 	case ISCSI_OP_NOOP_IN:
799 	case ISCSI_OP_SCSI_TMFUNC_RSP:
800 		rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
801 		break;
802 	default:
803 		rc = ISCSI_ERR_BAD_OPCODE;
804 		break;
805 	}
806 
807 	if (rc == 0) {
808 		/* Anything that comes with data should have
809 		 * been handled above. */
810 		if (tcp_conn->in.datalen)
811 			return ISCSI_ERR_PROTO;
812 		iscsi_tcp_hdr_recv_prep(tcp_conn);
813 	}
814 
815 	return rc;
816 }
817 
818 /**
819  * iscsi_tcp_hdr_recv_done - process PDU header
820  * @tcp_conn: iSCSI TCP connection
821  * @segment: the buffer segment being processed
822  *
823  * This is the callback invoked when the PDU header has
824  * been received. If the header is followed by additional
825  * header segments, we go back for more data.
826  */
827 static int
828 iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
829 			struct iscsi_segment *segment)
830 {
831 	struct iscsi_conn *conn = tcp_conn->iscsi_conn;
832 	struct iscsi_hdr *hdr;
833 
834 	/* Check if there are additional header segments
835 	 * *prior* to computing the digest, because we
836 	 * may need to go back to the caller for more.
837 	 */
838 	hdr = (struct iscsi_hdr *) tcp_conn->in.hdr_buf;
839 	if (segment->copied == sizeof(struct iscsi_hdr) && hdr->hlength) {
840 		/* Bump the header length - the caller will
841 		 * just loop around and get the AHS for us, and
842 		 * call again. */
843 		unsigned int ahslen = hdr->hlength << 2;
844 
845 		/* Make sure we don't overflow */
846 		if (sizeof(*hdr) + ahslen > sizeof(tcp_conn->in.hdr_buf))
847 			return ISCSI_ERR_AHSLEN;
848 
849 		segment->total_size += ahslen;
850 		segment->size += ahslen;
851 		return 0;
852 	}
853 
854 	/* We're done processing the header. See if we're doing
855 	 * header digests; if so, set up the recv_digest buffer
856 	 * and go back for more. */
857 	if (conn->hdrdgst_en &&
858 	    !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD)) {
859 		if (segment->digest_len == 0) {
860 			/*
861 			 * Even if we offload the digest processing we
862 			 * splice it in so we can increment the skb/segment
863 			 * counters in preparation for the data segment.
864 			 */
865 			iscsi_tcp_segment_splice_digest(segment,
866 							segment->recv_digest);
867 			return 0;
868 		}
869 
870 		iscsi_tcp_dgst_header(hdr,
871 				      segment->total_copied - ISCSI_DIGEST_SIZE,
872 				      segment->digest);
873 
874 		if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
875 			return ISCSI_ERR_HDR_DGST;
876 	}
877 
878 	tcp_conn->in.hdr = hdr;
879 	return iscsi_tcp_hdr_dissect(conn, hdr);
880 }
881 
882 /**
883  * iscsi_tcp_recv_segment_is_hdr - tests if we are reading in a header
884  * @tcp_conn: iscsi tcp conn
885  *
886  * returns non zero if we are currently processing or setup to process
887  * a header.
888  */
889 inline int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn)
890 {
891 	return tcp_conn->in.segment.done == iscsi_tcp_hdr_recv_done;
892 }
893 EXPORT_SYMBOL_GPL(iscsi_tcp_recv_segment_is_hdr);
894 
895 /**
896  * iscsi_tcp_recv_skb - Process skb
897  * @conn: iscsi connection
898  * @skb: network buffer with header and/or data segment
899  * @offset: offset in skb
900  * @offloaded: bool indicating if transfer was offloaded
901  * @status: iscsi TCP status result
902  *
903  * Will return status of transfer in @status. And will return
904  * number of bytes copied.
905  */
906 int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
907 		       unsigned int offset, bool offloaded, int *status)
908 {
909 	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
910 	struct iscsi_segment *segment = &tcp_conn->in.segment;
911 	struct skb_seq_state seq;
912 	unsigned int consumed = 0;
913 	int rc = 0;
914 
915 	ISCSI_DBG_TCP(conn, "in %d bytes\n", skb->len - offset);
916 	/*
917 	 * Update for each skb instead of pdu, because over slow networks a
918 	 * data_in's data could take a while to read in. We also want to
919 	 * account for r2ts.
920 	 */
921 	conn->last_recv = jiffies;
922 
923 	if (unlikely(test_bit(ISCSI_CONN_FLAG_SUSPEND_RX, &conn->flags))) {
924 		ISCSI_DBG_TCP(conn, "Rx suspended!\n");
925 		*status = ISCSI_TCP_SUSPENDED;
926 		return 0;
927 	}
928 
929 	if (offloaded) {
930 		segment->total_copied = segment->total_size;
931 		goto segment_done;
932 	}
933 
934 	skb_prepare_seq_read(skb, offset, skb->len, &seq);
935 	while (1) {
936 		unsigned int avail;
937 		const u8 *ptr;
938 
939 		avail = skb_seq_read(consumed, &ptr, &seq);
940 		if (avail == 0) {
941 			ISCSI_DBG_TCP(conn, "no more data avail. Consumed %d\n",
942 				      consumed);
943 			*status = ISCSI_TCP_SKB_DONE;
944 			goto skb_done;
945 		}
946 		BUG_ON(segment->copied >= segment->size);
947 
948 		ISCSI_DBG_TCP(conn, "skb %p ptr=%p avail=%u\n", skb, ptr,
949 			      avail);
950 		rc = iscsi_tcp_segment_recv(tcp_conn, segment, ptr, avail);
951 		BUG_ON(rc == 0);
952 		consumed += rc;
953 
954 		if (segment->total_copied >= segment->total_size) {
955 			skb_abort_seq_read(&seq);
956 			goto segment_done;
957 		}
958 	}
959 
960 segment_done:
961 	*status = ISCSI_TCP_SEGMENT_DONE;
962 	ISCSI_DBG_TCP(conn, "segment done\n");
963 	rc = segment->done(tcp_conn, segment);
964 	if (rc != 0) {
965 		*status = ISCSI_TCP_CONN_ERR;
966 		ISCSI_DBG_TCP(conn, "Error receiving PDU, errno=%d\n", rc);
967 		iscsi_conn_failure(conn, rc);
968 		return 0;
969 	}
970 	/* The done() functions sets up the next segment. */
971 
972 skb_done:
973 	conn->rxdata_octets += consumed;
974 	return consumed;
975 }
976 EXPORT_SYMBOL_GPL(iscsi_tcp_recv_skb);
977 
978 /**
979  * iscsi_tcp_task_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
980  * @task: scsi command task
981  */
982 int iscsi_tcp_task_init(struct iscsi_task *task)
983 {
984 	struct iscsi_tcp_task *tcp_task = task->dd_data;
985 	struct iscsi_conn *conn = task->conn;
986 	struct scsi_cmnd *sc = task->sc;
987 	int err;
988 
989 	if (!sc) {
990 		/*
991 		 * mgmt tasks do not have a scatterlist since they come
992 		 * in from the iscsi interface.
993 		 */
994 		ISCSI_DBG_TCP(conn, "mtask deq [itt 0x%x]\n", task->itt);
995 
996 		return conn->session->tt->init_pdu(task, 0, task->data_count);
997 	}
998 
999 	BUG_ON(kfifo_len(&tcp_task->r2tqueue));
1000 	tcp_task->exp_datasn = 0;
1001 
1002 	/* Prepare PDU, optionally w/ immediate data */
1003 	ISCSI_DBG_TCP(conn, "task deq [itt 0x%x imm %d unsol %d]\n",
1004 		      task->itt, task->imm_count, task->unsol_r2t.data_length);
1005 
1006 	err = conn->session->tt->init_pdu(task, 0, task->imm_count);
1007 	if (err)
1008 		return err;
1009 	task->imm_count = 0;
1010 	return 0;
1011 }
1012 EXPORT_SYMBOL_GPL(iscsi_tcp_task_init);
1013 
1014 static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
1015 {
1016 	struct iscsi_tcp_task *tcp_task = task->dd_data;
1017 	struct iscsi_r2t_info *r2t = NULL;
1018 
1019 	if (iscsi_task_has_unsol_data(task))
1020 		r2t = &task->unsol_r2t;
1021 	else {
1022 		spin_lock_bh(&tcp_task->queue2pool);
1023 		if (tcp_task->r2t) {
1024 			r2t = tcp_task->r2t;
1025 			/* Continue with this R2T? */
1026 			if (r2t->data_length <= r2t->sent) {
1027 				ISCSI_DBG_TCP(task->conn,
1028 					      "  done with r2t %p\n", r2t);
1029 				kfifo_in(&tcp_task->r2tpool.queue,
1030 					    (void *)&tcp_task->r2t,
1031 					    sizeof(void *));
1032 				tcp_task->r2t = r2t = NULL;
1033 			}
1034 		}
1035 
1036 		if (r2t == NULL) {
1037 			if (kfifo_out(&tcp_task->r2tqueue,
1038 			    (void *)&tcp_task->r2t, sizeof(void *)) !=
1039 			    sizeof(void *))
1040 				r2t = NULL;
1041 			else
1042 				r2t = tcp_task->r2t;
1043 		}
1044 		spin_unlock_bh(&tcp_task->queue2pool);
1045 	}
1046 
1047 	return r2t;
1048 }
1049 
1050 /**
1051  * iscsi_tcp_task_xmit - xmit normal PDU task
1052  * @task: iscsi command task
1053  *
1054  * We're expected to return 0 when everything was transmitted successfully,
1055  * -EAGAIN if there's still data in the queue, or != 0 for any other kind
1056  * of error.
1057  */
1058 int iscsi_tcp_task_xmit(struct iscsi_task *task)
1059 {
1060 	struct iscsi_conn *conn = task->conn;
1061 	struct iscsi_session *session = conn->session;
1062 	struct iscsi_r2t_info *r2t;
1063 	int rc = 0;
1064 
1065 flush:
1066 	/* Flush any pending data first. */
1067 	rc = session->tt->xmit_pdu(task);
1068 	if (rc < 0)
1069 		return rc;
1070 
1071 	/* mgmt command */
1072 	if (!task->sc) {
1073 		if (task->hdr->itt == RESERVED_ITT)
1074 			iscsi_put_task(task);
1075 		return 0;
1076 	}
1077 
1078 	/* Are we done already? */
1079 	if (task->sc->sc_data_direction != DMA_TO_DEVICE)
1080 		return 0;
1081 
1082 	r2t = iscsi_tcp_get_curr_r2t(task);
1083 	if (r2t == NULL) {
1084 		/* Waiting for more R2Ts to arrive. */
1085 		ISCSI_DBG_TCP(conn, "no R2Ts yet\n");
1086 		return 0;
1087 	}
1088 
1089 	rc = conn->session->tt->alloc_pdu(task, ISCSI_OP_SCSI_DATA_OUT);
1090 	if (rc)
1091 		return rc;
1092 	iscsi_prep_data_out_pdu(task, r2t, (struct iscsi_data *) task->hdr);
1093 
1094 	ISCSI_DBG_TCP(conn, "sol dout %p [dsn %d itt 0x%x doff %d dlen %d]\n",
1095 		      r2t, r2t->datasn - 1, task->hdr->itt,
1096 		      r2t->data_offset + r2t->sent, r2t->data_count);
1097 
1098 	rc = conn->session->tt->init_pdu(task, r2t->data_offset + r2t->sent,
1099 					 r2t->data_count);
1100 	if (rc) {
1101 		iscsi_conn_failure(conn, ISCSI_ERR_XMIT_FAILED);
1102 		return rc;
1103 	}
1104 
1105 	r2t->sent += r2t->data_count;
1106 	goto flush;
1107 }
1108 EXPORT_SYMBOL_GPL(iscsi_tcp_task_xmit);
1109 
1110 struct iscsi_cls_conn *
1111 iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
1112 		      uint32_t conn_idx)
1113 
1114 {
1115 	struct iscsi_conn *conn;
1116 	struct iscsi_cls_conn *cls_conn;
1117 	struct iscsi_tcp_conn *tcp_conn;
1118 
1119 	cls_conn = iscsi_conn_setup(cls_session,
1120 				    sizeof(*tcp_conn) + dd_data_size, conn_idx);
1121 	if (!cls_conn)
1122 		return NULL;
1123 	conn = cls_conn->dd_data;
1124 	/*
1125 	 * due to strange issues with iser these are not set
1126 	 * in iscsi_conn_setup
1127 	 */
1128 	conn->max_recv_dlength = ISCSI_DEF_MAX_RECV_SEG_LEN;
1129 
1130 	tcp_conn = conn->dd_data;
1131 	tcp_conn->iscsi_conn = conn;
1132 	tcp_conn->dd_data = conn->dd_data + sizeof(*tcp_conn);
1133 	return cls_conn;
1134 }
1135 EXPORT_SYMBOL_GPL(iscsi_tcp_conn_setup);
1136 
1137 void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn)
1138 {
1139 	iscsi_conn_teardown(cls_conn);
1140 }
1141 EXPORT_SYMBOL_GPL(iscsi_tcp_conn_teardown);
1142 
1143 int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session)
1144 {
1145 	int i;
1146 	int cmd_i;
1147 
1148 	/*
1149 	 * initialize per-task: R2T pool and xmit queue
1150 	 */
1151 	for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
1152 	        struct iscsi_task *task = session->cmds[cmd_i];
1153 		struct iscsi_tcp_task *tcp_task = task->dd_data;
1154 
1155 		/*
1156 		 * pre-allocated x2 as much r2ts to handle race when
1157 		 * target acks DataOut faster than we data_xmit() queues
1158 		 * could replenish r2tqueue.
1159 		 */
1160 
1161 		/* R2T pool */
1162 		if (iscsi_pool_init(&tcp_task->r2tpool,
1163 				    session->max_r2t * 2, NULL,
1164 				    sizeof(struct iscsi_r2t_info))) {
1165 			goto r2t_alloc_fail;
1166 		}
1167 
1168 		/* R2T xmit queue */
1169 		if (kfifo_alloc(&tcp_task->r2tqueue,
1170 		      session->max_r2t * 4 * sizeof(void*), GFP_KERNEL)) {
1171 			iscsi_pool_free(&tcp_task->r2tpool);
1172 			goto r2t_alloc_fail;
1173 		}
1174 		spin_lock_init(&tcp_task->pool2queue);
1175 		spin_lock_init(&tcp_task->queue2pool);
1176 	}
1177 
1178 	return 0;
1179 
1180 r2t_alloc_fail:
1181 	for (i = 0; i < cmd_i; i++) {
1182 		struct iscsi_task *task = session->cmds[i];
1183 		struct iscsi_tcp_task *tcp_task = task->dd_data;
1184 
1185 		kfifo_free(&tcp_task->r2tqueue);
1186 		iscsi_pool_free(&tcp_task->r2tpool);
1187 	}
1188 	return -ENOMEM;
1189 }
1190 EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_alloc);
1191 
1192 void iscsi_tcp_r2tpool_free(struct iscsi_session *session)
1193 {
1194 	int i;
1195 
1196 	for (i = 0; i < session->cmds_max; i++) {
1197 		struct iscsi_task *task = session->cmds[i];
1198 		struct iscsi_tcp_task *tcp_task = task->dd_data;
1199 
1200 		kfifo_free(&tcp_task->r2tqueue);
1201 		iscsi_pool_free(&tcp_task->r2tpool);
1202 	}
1203 }
1204 EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_free);
1205 
1206 int iscsi_tcp_set_max_r2t(struct iscsi_conn *conn, char *buf)
1207 {
1208 	struct iscsi_session *session = conn->session;
1209 	unsigned short r2ts = 0;
1210 
1211 	sscanf(buf, "%hu", &r2ts);
1212 	if (session->max_r2t == r2ts)
1213 		return 0;
1214 
1215 	if (!r2ts || !is_power_of_2(r2ts))
1216 		return -EINVAL;
1217 
1218 	session->max_r2t = r2ts;
1219 	iscsi_tcp_r2tpool_free(session);
1220 	return iscsi_tcp_r2tpool_alloc(session);
1221 }
1222 EXPORT_SYMBOL_GPL(iscsi_tcp_set_max_r2t);
1223 
1224 void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
1225 			      struct iscsi_stats *stats)
1226 {
1227 	struct iscsi_conn *conn = cls_conn->dd_data;
1228 
1229 	stats->txdata_octets = conn->txdata_octets;
1230 	stats->rxdata_octets = conn->rxdata_octets;
1231 	stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
1232 	stats->dataout_pdus = conn->dataout_pdus_cnt;
1233 	stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
1234 	stats->datain_pdus = conn->datain_pdus_cnt;
1235 	stats->r2t_pdus = conn->r2t_pdus_cnt;
1236 	stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
1237 	stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
1238 }
1239 EXPORT_SYMBOL_GPL(iscsi_tcp_conn_get_stats);
1240