xref: /linux/drivers/scsi/iscsi_tcp.c (revision a1ff5a7d78a036d6c2178ee5acd6ba4946243800)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * iSCSI Initiator over TCP/IP Data-Path
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  * See the file COPYING included with this distribution for more details.
12  *
13  * Credits:
14  *	Christoph Hellwig
15  *	FUJITA Tomonori
16  *	Arne Redlich
17  *	Zhenyu Wang
18  */
19 
20 #include <crypto/hash.h>
21 #include <linux/types.h>
22 #include <linux/inet.h>
23 #include <linux/slab.h>
24 #include <linux/sched/mm.h>
25 #include <linux/file.h>
26 #include <linux/blkdev.h>
27 #include <linux/delay.h>
28 #include <linux/kfifo.h>
29 #include <linux/scatterlist.h>
30 #include <linux/module.h>
31 #include <linux/backing-dev.h>
32 #include <net/tcp.h>
33 #include <scsi/scsi_cmnd.h>
34 #include <scsi/scsi_device.h>
35 #include <scsi/scsi_host.h>
36 #include <scsi/scsi.h>
37 #include <scsi/scsi_transport_iscsi.h>
38 #include <trace/events/iscsi.h>
39 #include <trace/events/sock.h>
40 
41 #include "iscsi_tcp.h"
42 
43 MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, "
44 	      "Dmitry Yusupov <dmitry_yus@yahoo.com>, "
45 	      "Alex Aizman <itn780@yahoo.com>");
46 MODULE_DESCRIPTION("iSCSI/TCP data-path");
47 MODULE_LICENSE("GPL");
48 
49 static struct scsi_transport_template *iscsi_sw_tcp_scsi_transport;
50 static const struct scsi_host_template iscsi_sw_tcp_sht;
51 static struct iscsi_transport iscsi_sw_tcp_transport;
52 
53 static unsigned int iscsi_max_lun = ~0;
54 module_param_named(max_lun, iscsi_max_lun, uint, S_IRUGO);
55 
56 static bool iscsi_recv_from_iscsi_q;
57 module_param_named(recv_from_iscsi_q, iscsi_recv_from_iscsi_q, bool, 0644);
58 MODULE_PARM_DESC(recv_from_iscsi_q, "Set to true to read iSCSI data/headers from the iscsi_q workqueue. The default is false which will perform reads from the network softirq context.");
59 
60 static int iscsi_sw_tcp_dbg;
61 module_param_named(debug_iscsi_tcp, iscsi_sw_tcp_dbg, int,
62 		   S_IRUGO | S_IWUSR);
63 MODULE_PARM_DESC(debug_iscsi_tcp, "Turn on debugging for iscsi_tcp module "
64 		 "Set to 1 to turn on, and zero to turn off. Default is off.");
65 
66 #define ISCSI_SW_TCP_DBG(_conn, dbg_fmt, arg...)		\
67 	do {							\
68 		if (iscsi_sw_tcp_dbg)				\
69 			iscsi_conn_printk(KERN_INFO, _conn,	\
70 					     "%s " dbg_fmt,	\
71 					     __func__, ##arg);	\
72 		iscsi_dbg_trace(trace_iscsi_dbg_sw_tcp,		\
73 				&(_conn)->cls_conn->dev,	\
74 				"%s " dbg_fmt, __func__, ##arg);\
75 	} while (0);
76 
77 
78 /**
79  * iscsi_sw_tcp_recv - TCP receive in sendfile fashion
80  * @rd_desc: read descriptor
81  * @skb: socket buffer
82  * @offset: offset in skb
83  * @len: skb->len - offset
84  */
iscsi_sw_tcp_recv(read_descriptor_t * rd_desc,struct sk_buff * skb,unsigned int offset,size_t len)85 static int iscsi_sw_tcp_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
86 			     unsigned int offset, size_t len)
87 {
88 	struct iscsi_conn *conn = rd_desc->arg.data;
89 	unsigned int consumed, total_consumed = 0;
90 	int status;
91 
92 	ISCSI_SW_TCP_DBG(conn, "in %d bytes\n", skb->len - offset);
93 
94 	do {
95 		status = 0;
96 		consumed = iscsi_tcp_recv_skb(conn, skb, offset, 0, &status);
97 		offset += consumed;
98 		total_consumed += consumed;
99 	} while (consumed != 0 && status != ISCSI_TCP_SKB_DONE);
100 
101 	ISCSI_SW_TCP_DBG(conn, "read %d bytes status %d\n",
102 			 skb->len - offset, status);
103 	return total_consumed;
104 }
105 
106 /**
107  * iscsi_sw_sk_state_check - check socket state
108  * @sk: socket
109  *
110  * If the socket is in CLOSE or CLOSE_WAIT we should
111  * not close the connection if there is still some
112  * data pending.
113  *
114  * Must be called with sk_callback_lock.
115  */
iscsi_sw_sk_state_check(struct sock * sk)116 static inline int iscsi_sw_sk_state_check(struct sock *sk)
117 {
118 	struct iscsi_conn *conn = sk->sk_user_data;
119 
120 	if ((sk->sk_state == TCP_CLOSE_WAIT || sk->sk_state == TCP_CLOSE) &&
121 	    (conn->session->state != ISCSI_STATE_LOGGING_OUT) &&
122 	    !atomic_read(&sk->sk_rmem_alloc)) {
123 		ISCSI_SW_TCP_DBG(conn, "TCP_CLOSE|TCP_CLOSE_WAIT\n");
124 		iscsi_conn_failure(conn, ISCSI_ERR_TCP_CONN_CLOSE);
125 		return -ECONNRESET;
126 	}
127 	return 0;
128 }
129 
iscsi_sw_tcp_recv_data(struct iscsi_conn * conn)130 static void iscsi_sw_tcp_recv_data(struct iscsi_conn *conn)
131 {
132 	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
133 	struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
134 	struct sock *sk = tcp_sw_conn->sock->sk;
135 	read_descriptor_t rd_desc;
136 
137 	/*
138 	 * Use rd_desc to pass 'conn' to iscsi_tcp_recv.
139 	 * We set count to 1 because we want the network layer to
140 	 * hand us all the skbs that are available. iscsi_tcp_recv
141 	 * handled pdus that cross buffers or pdus that still need data.
142 	 */
143 	rd_desc.arg.data = conn;
144 	rd_desc.count = 1;
145 
146 	tcp_read_sock(sk, &rd_desc, iscsi_sw_tcp_recv);
147 
148 	/* If we had to (atomically) map a highmem page,
149 	 * unmap it now. */
150 	iscsi_tcp_segment_unmap(&tcp_conn->in.segment);
151 
152 	iscsi_sw_sk_state_check(sk);
153 }
154 
iscsi_sw_tcp_recv_data_work(struct work_struct * work)155 static void iscsi_sw_tcp_recv_data_work(struct work_struct *work)
156 {
157 	struct iscsi_conn *conn = container_of(work, struct iscsi_conn,
158 					       recvwork);
159 	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
160 	struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
161 	struct sock *sk = tcp_sw_conn->sock->sk;
162 
163 	lock_sock(sk);
164 	iscsi_sw_tcp_recv_data(conn);
165 	release_sock(sk);
166 }
167 
iscsi_sw_tcp_data_ready(struct sock * sk)168 static void iscsi_sw_tcp_data_ready(struct sock *sk)
169 {
170 	struct iscsi_sw_tcp_conn *tcp_sw_conn;
171 	struct iscsi_tcp_conn *tcp_conn;
172 	struct iscsi_conn *conn;
173 
174 	trace_sk_data_ready(sk);
175 
176 	read_lock_bh(&sk->sk_callback_lock);
177 	conn = sk->sk_user_data;
178 	if (!conn) {
179 		read_unlock_bh(&sk->sk_callback_lock);
180 		return;
181 	}
182 	tcp_conn = conn->dd_data;
183 	tcp_sw_conn = tcp_conn->dd_data;
184 
185 	if (tcp_sw_conn->queue_recv)
186 		iscsi_conn_queue_recv(conn);
187 	else
188 		iscsi_sw_tcp_recv_data(conn);
189 	read_unlock_bh(&sk->sk_callback_lock);
190 }
191 
iscsi_sw_tcp_state_change(struct sock * sk)192 static void iscsi_sw_tcp_state_change(struct sock *sk)
193 {
194 	struct iscsi_tcp_conn *tcp_conn;
195 	struct iscsi_sw_tcp_conn *tcp_sw_conn;
196 	struct iscsi_conn *conn;
197 	void (*old_state_change)(struct sock *);
198 
199 	read_lock_bh(&sk->sk_callback_lock);
200 	conn = sk->sk_user_data;
201 	if (!conn) {
202 		read_unlock_bh(&sk->sk_callback_lock);
203 		return;
204 	}
205 
206 	iscsi_sw_sk_state_check(sk);
207 
208 	tcp_conn = conn->dd_data;
209 	tcp_sw_conn = tcp_conn->dd_data;
210 	old_state_change = tcp_sw_conn->old_state_change;
211 
212 	read_unlock_bh(&sk->sk_callback_lock);
213 
214 	old_state_change(sk);
215 }
216 
217 /**
218  * iscsi_sw_tcp_write_space - Called when more output buffer space is available
219  * @sk: socket space is available for
220  **/
iscsi_sw_tcp_write_space(struct sock * sk)221 static void iscsi_sw_tcp_write_space(struct sock *sk)
222 {
223 	struct iscsi_conn *conn;
224 	struct iscsi_tcp_conn *tcp_conn;
225 	struct iscsi_sw_tcp_conn *tcp_sw_conn;
226 	void (*old_write_space)(struct sock *);
227 
228 	read_lock_bh(&sk->sk_callback_lock);
229 	conn = sk->sk_user_data;
230 	if (!conn) {
231 		read_unlock_bh(&sk->sk_callback_lock);
232 		return;
233 	}
234 
235 	tcp_conn = conn->dd_data;
236 	tcp_sw_conn = tcp_conn->dd_data;
237 	old_write_space = tcp_sw_conn->old_write_space;
238 	read_unlock_bh(&sk->sk_callback_lock);
239 
240 	old_write_space(sk);
241 
242 	ISCSI_SW_TCP_DBG(conn, "iscsi_write_space\n");
243 	iscsi_conn_queue_xmit(conn);
244 }
245 
iscsi_sw_tcp_conn_set_callbacks(struct iscsi_conn * conn)246 static void iscsi_sw_tcp_conn_set_callbacks(struct iscsi_conn *conn)
247 {
248 	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
249 	struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
250 	struct sock *sk = tcp_sw_conn->sock->sk;
251 
252 	/* assign new callbacks */
253 	write_lock_bh(&sk->sk_callback_lock);
254 	sk->sk_user_data = conn;
255 	tcp_sw_conn->old_data_ready = sk->sk_data_ready;
256 	tcp_sw_conn->old_state_change = sk->sk_state_change;
257 	tcp_sw_conn->old_write_space = sk->sk_write_space;
258 	sk->sk_data_ready = iscsi_sw_tcp_data_ready;
259 	sk->sk_state_change = iscsi_sw_tcp_state_change;
260 	sk->sk_write_space = iscsi_sw_tcp_write_space;
261 	write_unlock_bh(&sk->sk_callback_lock);
262 }
263 
264 static void
iscsi_sw_tcp_conn_restore_callbacks(struct iscsi_conn * conn)265 iscsi_sw_tcp_conn_restore_callbacks(struct iscsi_conn *conn)
266 {
267 	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
268 	struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
269 	struct sock *sk = tcp_sw_conn->sock->sk;
270 
271 	/* restore socket callbacks, see also: iscsi_conn_set_callbacks() */
272 	write_lock_bh(&sk->sk_callback_lock);
273 	sk->sk_user_data    = NULL;
274 	sk->sk_data_ready   = tcp_sw_conn->old_data_ready;
275 	sk->sk_state_change = tcp_sw_conn->old_state_change;
276 	sk->sk_write_space  = tcp_sw_conn->old_write_space;
277 	sk->sk_no_check_tx = 0;
278 	write_unlock_bh(&sk->sk_callback_lock);
279 }
280 
281 /**
282  * iscsi_sw_tcp_xmit_segment - transmit segment
283  * @tcp_conn: the iSCSI TCP connection
284  * @segment: the buffer to transmnit
285  *
286  * This function transmits as much of the buffer as
287  * the network layer will accept, and returns the number of
288  * bytes transmitted.
289  *
290  * If CRC hashing is enabled, the function will compute the
291  * hash as it goes. When the entire segment has been transmitted,
292  * it will retrieve the hash value and send it as well.
293  */
iscsi_sw_tcp_xmit_segment(struct iscsi_tcp_conn * tcp_conn,struct iscsi_segment * segment)294 static int iscsi_sw_tcp_xmit_segment(struct iscsi_tcp_conn *tcp_conn,
295 				     struct iscsi_segment *segment)
296 {
297 	struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
298 	struct socket *sk = tcp_sw_conn->sock;
299 	unsigned int copied = 0;
300 	int r = 0;
301 
302 	while (!iscsi_tcp_segment_done(tcp_conn, segment, 0, r)) {
303 		struct scatterlist *sg;
304 		struct msghdr msg = {};
305 		struct bio_vec bv;
306 		unsigned int offset, copy;
307 
308 		r = 0;
309 		offset = segment->copied;
310 		copy = segment->size - offset;
311 
312 		if (segment->total_copied + segment->size < segment->total_size)
313 			msg.msg_flags |= MSG_MORE;
314 
315 		if (tcp_sw_conn->queue_recv)
316 			msg.msg_flags |= MSG_DONTWAIT;
317 
318 		if (!segment->data) {
319 			if (!tcp_conn->iscsi_conn->datadgst_en)
320 				msg.msg_flags |= MSG_SPLICE_PAGES;
321 			sg = segment->sg;
322 			offset += segment->sg_offset + sg->offset;
323 			bvec_set_page(&bv, sg_page(sg), copy, offset);
324 		} else {
325 			bvec_set_virt(&bv, segment->data + offset, copy);
326 		}
327 		iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bv, 1, copy);
328 
329 		r = sock_sendmsg(sk, &msg);
330 		if (r < 0) {
331 			iscsi_tcp_segment_unmap(segment);
332 			return r;
333 		}
334 		copied += r;
335 	}
336 	return copied;
337 }
338 
339 /**
340  * iscsi_sw_tcp_xmit - TCP transmit
341  * @conn: iscsi connection
342  **/
iscsi_sw_tcp_xmit(struct iscsi_conn * conn)343 static int iscsi_sw_tcp_xmit(struct iscsi_conn *conn)
344 {
345 	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
346 	struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
347 	struct iscsi_segment *segment = &tcp_sw_conn->out.segment;
348 	unsigned int consumed = 0;
349 	int rc = 0;
350 
351 	while (1) {
352 		rc = iscsi_sw_tcp_xmit_segment(tcp_conn, segment);
353 		/*
354 		 * We may not have been able to send data because the conn
355 		 * is getting stopped. libiscsi will know so propagate err
356 		 * for it to do the right thing.
357 		 */
358 		if (rc == -EAGAIN)
359 			return rc;
360 		else if (rc < 0) {
361 			rc = ISCSI_ERR_XMIT_FAILED;
362 			goto error;
363 		} else if (rc == 0)
364 			break;
365 
366 		consumed += rc;
367 
368 		if (segment->total_copied >= segment->total_size) {
369 			if (segment->done != NULL) {
370 				rc = segment->done(tcp_conn, segment);
371 				if (rc != 0)
372 					goto error;
373 			}
374 		}
375 	}
376 
377 	ISCSI_SW_TCP_DBG(conn, "xmit %d bytes\n", consumed);
378 
379 	conn->txdata_octets += consumed;
380 	return consumed;
381 
382 error:
383 	/* Transmit error. We could initiate error recovery
384 	 * here. */
385 	ISCSI_SW_TCP_DBG(conn, "Error sending PDU, errno=%d\n", rc);
386 	iscsi_conn_failure(conn, rc);
387 	return -EIO;
388 }
389 
390 /**
391  * iscsi_sw_tcp_xmit_qlen - return the number of bytes queued for xmit
392  * @conn: iscsi connection
393  */
iscsi_sw_tcp_xmit_qlen(struct iscsi_conn * conn)394 static inline int iscsi_sw_tcp_xmit_qlen(struct iscsi_conn *conn)
395 {
396 	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
397 	struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
398 	struct iscsi_segment *segment = &tcp_sw_conn->out.segment;
399 
400 	return segment->total_copied - segment->total_size;
401 }
402 
iscsi_sw_tcp_pdu_xmit(struct iscsi_task * task)403 static int iscsi_sw_tcp_pdu_xmit(struct iscsi_task *task)
404 {
405 	struct iscsi_conn *conn = task->conn;
406 	unsigned int noreclaim_flag;
407 	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
408 	struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
409 	int rc = 0;
410 
411 	if (!tcp_sw_conn->sock) {
412 		iscsi_conn_printk(KERN_ERR, conn,
413 				  "Transport not bound to socket!\n");
414 		return -EINVAL;
415 	}
416 
417 	noreclaim_flag = memalloc_noreclaim_save();
418 
419 	while (iscsi_sw_tcp_xmit_qlen(conn)) {
420 		rc = iscsi_sw_tcp_xmit(conn);
421 		if (rc == 0) {
422 			rc = -EAGAIN;
423 			break;
424 		}
425 		if (rc < 0)
426 			break;
427 		rc = 0;
428 	}
429 
430 	memalloc_noreclaim_restore(noreclaim_flag);
431 	return rc;
432 }
433 
434 /*
435  * This is called when we're done sending the header.
436  * Simply copy the data_segment to the send segment, and return.
437  */
iscsi_sw_tcp_send_hdr_done(struct iscsi_tcp_conn * tcp_conn,struct iscsi_segment * segment)438 static int iscsi_sw_tcp_send_hdr_done(struct iscsi_tcp_conn *tcp_conn,
439 				      struct iscsi_segment *segment)
440 {
441 	struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
442 
443 	tcp_sw_conn->out.segment = tcp_sw_conn->out.data_segment;
444 	ISCSI_SW_TCP_DBG(tcp_conn->iscsi_conn,
445 			 "Header done. Next segment size %u total_size %u\n",
446 			 tcp_sw_conn->out.segment.size,
447 			 tcp_sw_conn->out.segment.total_size);
448 	return 0;
449 }
450 
iscsi_sw_tcp_send_hdr_prep(struct iscsi_conn * conn,void * hdr,size_t hdrlen)451 static void iscsi_sw_tcp_send_hdr_prep(struct iscsi_conn *conn, void *hdr,
452 				       size_t hdrlen)
453 {
454 	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
455 	struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
456 
457 	ISCSI_SW_TCP_DBG(conn, "%s\n", conn->hdrdgst_en ?
458 			 "digest enabled" : "digest disabled");
459 
460 	/* Clear the data segment - needs to be filled in by the
461 	 * caller using iscsi_tcp_send_data_prep() */
462 	memset(&tcp_sw_conn->out.data_segment, 0,
463 	       sizeof(struct iscsi_segment));
464 
465 	/* If header digest is enabled, compute the CRC and
466 	 * place the digest into the same buffer. We make
467 	 * sure that both iscsi_tcp_task and mtask have
468 	 * sufficient room.
469 	 */
470 	if (conn->hdrdgst_en) {
471 		iscsi_tcp_dgst_header(tcp_sw_conn->tx_hash, hdr, hdrlen,
472 				      hdr + hdrlen);
473 		hdrlen += ISCSI_DIGEST_SIZE;
474 	}
475 
476 	/* Remember header pointer for later, when we need
477 	 * to decide whether there's a payload to go along
478 	 * with the header. */
479 	tcp_sw_conn->out.hdr = hdr;
480 
481 	iscsi_segment_init_linear(&tcp_sw_conn->out.segment, hdr, hdrlen,
482 				  iscsi_sw_tcp_send_hdr_done, NULL);
483 }
484 
485 /*
486  * Prepare the send buffer for the payload data.
487  * Padding and checksumming will all be taken care
488  * of by the iscsi_segment routines.
489  */
490 static int
iscsi_sw_tcp_send_data_prep(struct iscsi_conn * conn,struct scatterlist * sg,unsigned int count,unsigned int offset,unsigned int len)491 iscsi_sw_tcp_send_data_prep(struct iscsi_conn *conn, struct scatterlist *sg,
492 			    unsigned int count, unsigned int offset,
493 			    unsigned int len)
494 {
495 	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
496 	struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
497 	struct ahash_request *tx_hash = NULL;
498 	unsigned int hdr_spec_len;
499 
500 	ISCSI_SW_TCP_DBG(conn, "offset=%d, datalen=%d %s\n", offset, len,
501 			 conn->datadgst_en ?
502 			 "digest enabled" : "digest disabled");
503 
504 	/* Make sure the datalen matches what the caller
505 	   said he would send. */
506 	hdr_spec_len = ntoh24(tcp_sw_conn->out.hdr->dlength);
507 	WARN_ON(iscsi_padded(len) != iscsi_padded(hdr_spec_len));
508 
509 	if (conn->datadgst_en)
510 		tx_hash = tcp_sw_conn->tx_hash;
511 
512 	return iscsi_segment_seek_sg(&tcp_sw_conn->out.data_segment,
513 				     sg, count, offset, len,
514 				     NULL, tx_hash);
515 }
516 
517 static void
iscsi_sw_tcp_send_linear_data_prep(struct iscsi_conn * conn,void * data,size_t len)518 iscsi_sw_tcp_send_linear_data_prep(struct iscsi_conn *conn, void *data,
519 				   size_t len)
520 {
521 	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
522 	struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
523 	struct ahash_request *tx_hash = NULL;
524 	unsigned int hdr_spec_len;
525 
526 	ISCSI_SW_TCP_DBG(conn, "datalen=%zd %s\n", len, conn->datadgst_en ?
527 			 "digest enabled" : "digest disabled");
528 
529 	/* Make sure the datalen matches what the caller
530 	   said he would send. */
531 	hdr_spec_len = ntoh24(tcp_sw_conn->out.hdr->dlength);
532 	WARN_ON(iscsi_padded(len) != iscsi_padded(hdr_spec_len));
533 
534 	if (conn->datadgst_en)
535 		tx_hash = tcp_sw_conn->tx_hash;
536 
537 	iscsi_segment_init_linear(&tcp_sw_conn->out.data_segment,
538 				data, len, NULL, tx_hash);
539 }
540 
iscsi_sw_tcp_pdu_init(struct iscsi_task * task,unsigned int offset,unsigned int count)541 static int iscsi_sw_tcp_pdu_init(struct iscsi_task *task,
542 				 unsigned int offset, unsigned int count)
543 {
544 	struct iscsi_conn *conn = task->conn;
545 	int err = 0;
546 
547 	iscsi_sw_tcp_send_hdr_prep(conn, task->hdr, task->hdr_len);
548 
549 	if (!count)
550 		return 0;
551 
552 	if (!task->sc)
553 		iscsi_sw_tcp_send_linear_data_prep(conn, task->data, count);
554 	else {
555 		struct scsi_data_buffer *sdb = &task->sc->sdb;
556 
557 		err = iscsi_sw_tcp_send_data_prep(conn, sdb->table.sgl,
558 						  sdb->table.nents, offset,
559 						  count);
560 	}
561 
562 	if (err) {
563 		/* got invalid offset/len */
564 		return -EIO;
565 	}
566 	return 0;
567 }
568 
iscsi_sw_tcp_pdu_alloc(struct iscsi_task * task,uint8_t opcode)569 static int iscsi_sw_tcp_pdu_alloc(struct iscsi_task *task, uint8_t opcode)
570 {
571 	struct iscsi_tcp_task *tcp_task = task->dd_data;
572 
573 	task->hdr = task->dd_data + sizeof(*tcp_task);
574 	task->hdr_max = sizeof(struct iscsi_sw_tcp_hdrbuf) - ISCSI_DIGEST_SIZE;
575 	return 0;
576 }
577 
578 static struct iscsi_cls_conn *
iscsi_sw_tcp_conn_create(struct iscsi_cls_session * cls_session,uint32_t conn_idx)579 iscsi_sw_tcp_conn_create(struct iscsi_cls_session *cls_session,
580 			 uint32_t conn_idx)
581 {
582 	struct iscsi_conn *conn;
583 	struct iscsi_cls_conn *cls_conn;
584 	struct iscsi_tcp_conn *tcp_conn;
585 	struct iscsi_sw_tcp_conn *tcp_sw_conn;
586 	struct crypto_ahash *tfm;
587 
588 	cls_conn = iscsi_tcp_conn_setup(cls_session, sizeof(*tcp_sw_conn),
589 					conn_idx);
590 	if (!cls_conn)
591 		return NULL;
592 	conn = cls_conn->dd_data;
593 	tcp_conn = conn->dd_data;
594 	tcp_sw_conn = tcp_conn->dd_data;
595 	INIT_WORK(&conn->recvwork, iscsi_sw_tcp_recv_data_work);
596 	tcp_sw_conn->queue_recv = iscsi_recv_from_iscsi_q;
597 
598 	mutex_init(&tcp_sw_conn->sock_lock);
599 
600 	tfm = crypto_alloc_ahash("crc32c", 0, CRYPTO_ALG_ASYNC);
601 	if (IS_ERR(tfm))
602 		goto free_conn;
603 
604 	tcp_sw_conn->tx_hash = ahash_request_alloc(tfm, GFP_KERNEL);
605 	if (!tcp_sw_conn->tx_hash)
606 		goto free_tfm;
607 	ahash_request_set_callback(tcp_sw_conn->tx_hash, 0, NULL, NULL);
608 
609 	tcp_sw_conn->rx_hash = ahash_request_alloc(tfm, GFP_KERNEL);
610 	if (!tcp_sw_conn->rx_hash)
611 		goto free_tx_hash;
612 	ahash_request_set_callback(tcp_sw_conn->rx_hash, 0, NULL, NULL);
613 
614 	tcp_conn->rx_hash = tcp_sw_conn->rx_hash;
615 
616 	return cls_conn;
617 
618 free_tx_hash:
619 	ahash_request_free(tcp_sw_conn->tx_hash);
620 free_tfm:
621 	crypto_free_ahash(tfm);
622 free_conn:
623 	iscsi_conn_printk(KERN_ERR, conn,
624 			  "Could not create connection due to crc32c "
625 			  "loading error. Make sure the crc32c "
626 			  "module is built as a module or into the "
627 			  "kernel\n");
628 	iscsi_tcp_conn_teardown(cls_conn);
629 	return NULL;
630 }
631 
iscsi_sw_tcp_release_conn(struct iscsi_conn * conn)632 static void iscsi_sw_tcp_release_conn(struct iscsi_conn *conn)
633 {
634 	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
635 	struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
636 	struct socket *sock = tcp_sw_conn->sock;
637 
638 	/*
639 	 * The iscsi transport class will make sure we are not called in
640 	 * parallel with start, stop, bind and destroys. However, this can be
641 	 * called twice if userspace does a stop then a destroy.
642 	 */
643 	if (!sock)
644 		return;
645 
646 	/*
647 	 * Make sure we start socket shutdown now in case userspace is up
648 	 * but delayed in releasing the socket.
649 	 */
650 	kernel_sock_shutdown(sock, SHUT_RDWR);
651 
652 	sock_hold(sock->sk);
653 	iscsi_sw_tcp_conn_restore_callbacks(conn);
654 	sock_put(sock->sk);
655 
656 	iscsi_suspend_rx(conn);
657 
658 	mutex_lock(&tcp_sw_conn->sock_lock);
659 	tcp_sw_conn->sock = NULL;
660 	mutex_unlock(&tcp_sw_conn->sock_lock);
661 	sockfd_put(sock);
662 }
663 
iscsi_sw_tcp_conn_destroy(struct iscsi_cls_conn * cls_conn)664 static void iscsi_sw_tcp_conn_destroy(struct iscsi_cls_conn *cls_conn)
665 {
666 	struct iscsi_conn *conn = cls_conn->dd_data;
667 	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
668 	struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
669 
670 	iscsi_sw_tcp_release_conn(conn);
671 
672 	ahash_request_free(tcp_sw_conn->rx_hash);
673 	if (tcp_sw_conn->tx_hash) {
674 		struct crypto_ahash *tfm;
675 
676 		tfm = crypto_ahash_reqtfm(tcp_sw_conn->tx_hash);
677 		ahash_request_free(tcp_sw_conn->tx_hash);
678 		crypto_free_ahash(tfm);
679 	}
680 
681 	iscsi_tcp_conn_teardown(cls_conn);
682 }
683 
iscsi_sw_tcp_conn_stop(struct iscsi_cls_conn * cls_conn,int flag)684 static void iscsi_sw_tcp_conn_stop(struct iscsi_cls_conn *cls_conn, int flag)
685 {
686 	struct iscsi_conn *conn = cls_conn->dd_data;
687 	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
688 	struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
689 	struct socket *sock = tcp_sw_conn->sock;
690 
691 	/* userspace may have goofed up and not bound us */
692 	if (!sock)
693 		return;
694 
695 	sock->sk->sk_err = EIO;
696 	wake_up_interruptible(sk_sleep(sock->sk));
697 
698 	/* stop xmit side */
699 	iscsi_suspend_tx(conn);
700 
701 	/* stop recv side and release socket */
702 	iscsi_sw_tcp_release_conn(conn);
703 
704 	iscsi_conn_stop(cls_conn, flag);
705 }
706 
707 static int
iscsi_sw_tcp_conn_bind(struct iscsi_cls_session * cls_session,struct iscsi_cls_conn * cls_conn,uint64_t transport_eph,int is_leading)708 iscsi_sw_tcp_conn_bind(struct iscsi_cls_session *cls_session,
709 		       struct iscsi_cls_conn *cls_conn, uint64_t transport_eph,
710 		       int is_leading)
711 {
712 	struct iscsi_conn *conn = cls_conn->dd_data;
713 	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
714 	struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
715 	struct sock *sk;
716 	struct socket *sock;
717 	int err;
718 
719 	/* lookup for existing socket */
720 	sock = sockfd_lookup((int)transport_eph, &err);
721 	if (!sock) {
722 		iscsi_conn_printk(KERN_ERR, conn,
723 				  "sockfd_lookup failed %d\n", err);
724 		return -EEXIST;
725 	}
726 
727 	err = -EINVAL;
728 	if (!sk_is_tcp(sock->sk))
729 		goto free_socket;
730 
731 	err = iscsi_conn_bind(cls_session, cls_conn, is_leading);
732 	if (err)
733 		goto free_socket;
734 
735 	mutex_lock(&tcp_sw_conn->sock_lock);
736 	/* bind iSCSI connection and socket */
737 	tcp_sw_conn->sock = sock;
738 	mutex_unlock(&tcp_sw_conn->sock_lock);
739 
740 	/* setup Socket parameters */
741 	sk = sock->sk;
742 	sk->sk_reuse = SK_CAN_REUSE;
743 	sk->sk_sndtimeo = 15 * HZ; /* FIXME: make it configurable */
744 	sk->sk_allocation = GFP_ATOMIC;
745 	sk->sk_use_task_frag = false;
746 	sk_set_memalloc(sk);
747 	sock_no_linger(sk);
748 
749 	iscsi_sw_tcp_conn_set_callbacks(conn);
750 	/*
751 	 * set receive state machine into initial state
752 	 */
753 	iscsi_tcp_hdr_recv_prep(tcp_conn);
754 	return 0;
755 
756 free_socket:
757 	sockfd_put(sock);
758 	return err;
759 }
760 
iscsi_sw_tcp_conn_set_param(struct iscsi_cls_conn * cls_conn,enum iscsi_param param,char * buf,int buflen)761 static int iscsi_sw_tcp_conn_set_param(struct iscsi_cls_conn *cls_conn,
762 				       enum iscsi_param param, char *buf,
763 				       int buflen)
764 {
765 	struct iscsi_conn *conn = cls_conn->dd_data;
766 	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
767 	struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
768 
769 	switch(param) {
770 	case ISCSI_PARAM_HDRDGST_EN:
771 		iscsi_set_param(cls_conn, param, buf, buflen);
772 		break;
773 	case ISCSI_PARAM_DATADGST_EN:
774 		mutex_lock(&tcp_sw_conn->sock_lock);
775 		if (!tcp_sw_conn->sock) {
776 			mutex_unlock(&tcp_sw_conn->sock_lock);
777 			return -ENOTCONN;
778 		}
779 		iscsi_set_param(cls_conn, param, buf, buflen);
780 		mutex_unlock(&tcp_sw_conn->sock_lock);
781 		break;
782 	case ISCSI_PARAM_MAX_R2T:
783 		return iscsi_tcp_set_max_r2t(conn, buf);
784 	default:
785 		return iscsi_set_param(cls_conn, param, buf, buflen);
786 	}
787 
788 	return 0;
789 }
790 
iscsi_sw_tcp_conn_get_param(struct iscsi_cls_conn * cls_conn,enum iscsi_param param,char * buf)791 static int iscsi_sw_tcp_conn_get_param(struct iscsi_cls_conn *cls_conn,
792 				       enum iscsi_param param, char *buf)
793 {
794 	struct iscsi_conn *conn = cls_conn->dd_data;
795 	struct iscsi_sw_tcp_conn *tcp_sw_conn;
796 	struct iscsi_tcp_conn *tcp_conn;
797 	struct sockaddr_in6 addr;
798 	struct socket *sock;
799 	int rc;
800 
801 	switch(param) {
802 	case ISCSI_PARAM_CONN_PORT:
803 	case ISCSI_PARAM_CONN_ADDRESS:
804 	case ISCSI_PARAM_LOCAL_PORT:
805 		spin_lock_bh(&conn->session->frwd_lock);
806 		if (!conn->session->leadconn) {
807 			spin_unlock_bh(&conn->session->frwd_lock);
808 			return -ENOTCONN;
809 		}
810 		/*
811 		 * The conn has been setup and bound, so just grab a ref
812 		 * incase a destroy runs while we are in the net layer.
813 		 */
814 		iscsi_get_conn(conn->cls_conn);
815 		spin_unlock_bh(&conn->session->frwd_lock);
816 
817 		tcp_conn = conn->dd_data;
818 		tcp_sw_conn = tcp_conn->dd_data;
819 
820 		mutex_lock(&tcp_sw_conn->sock_lock);
821 		sock = tcp_sw_conn->sock;
822 		if (!sock) {
823 			rc = -ENOTCONN;
824 			goto sock_unlock;
825 		}
826 
827 		if (param == ISCSI_PARAM_LOCAL_PORT)
828 			rc = kernel_getsockname(sock,
829 						(struct sockaddr *)&addr);
830 		else
831 			rc = kernel_getpeername(sock,
832 						(struct sockaddr *)&addr);
833 sock_unlock:
834 		mutex_unlock(&tcp_sw_conn->sock_lock);
835 		iscsi_put_conn(conn->cls_conn);
836 		if (rc < 0)
837 			return rc;
838 
839 		return iscsi_conn_get_addr_param((struct sockaddr_storage *)
840 						 &addr, param, buf);
841 	default:
842 		return iscsi_conn_get_param(cls_conn, param, buf);
843 	}
844 
845 	return 0;
846 }
847 
iscsi_sw_tcp_host_get_param(struct Scsi_Host * shost,enum iscsi_host_param param,char * buf)848 static int iscsi_sw_tcp_host_get_param(struct Scsi_Host *shost,
849 				       enum iscsi_host_param param, char *buf)
850 {
851 	struct iscsi_sw_tcp_host *tcp_sw_host = iscsi_host_priv(shost);
852 	struct iscsi_session *session;
853 	struct iscsi_conn *conn;
854 	struct iscsi_tcp_conn *tcp_conn;
855 	struct iscsi_sw_tcp_conn *tcp_sw_conn;
856 	struct sockaddr_in6 addr;
857 	struct socket *sock;
858 	int rc;
859 
860 	switch (param) {
861 	case ISCSI_HOST_PARAM_IPADDRESS:
862 		session = tcp_sw_host->session;
863 		if (!session)
864 			return -ENOTCONN;
865 
866 		spin_lock_bh(&session->frwd_lock);
867 		conn = session->leadconn;
868 		if (!conn) {
869 			spin_unlock_bh(&session->frwd_lock);
870 			return -ENOTCONN;
871 		}
872 		tcp_conn = conn->dd_data;
873 		tcp_sw_conn = tcp_conn->dd_data;
874 		/*
875 		 * The conn has been setup and bound, so just grab a ref
876 		 * incase a destroy runs while we are in the net layer.
877 		 */
878 		iscsi_get_conn(conn->cls_conn);
879 		spin_unlock_bh(&session->frwd_lock);
880 
881 		mutex_lock(&tcp_sw_conn->sock_lock);
882 		sock = tcp_sw_conn->sock;
883 		if (!sock)
884 			rc = -ENOTCONN;
885 		else
886 			rc = kernel_getsockname(sock, (struct sockaddr *)&addr);
887 		mutex_unlock(&tcp_sw_conn->sock_lock);
888 		iscsi_put_conn(conn->cls_conn);
889 		if (rc < 0)
890 			return rc;
891 
892 		return iscsi_conn_get_addr_param((struct sockaddr_storage *)
893 						 &addr,
894 						 (enum iscsi_param)param, buf);
895 	default:
896 		return iscsi_host_get_param(shost, param, buf);
897 	}
898 
899 	return 0;
900 }
901 
902 static void
iscsi_sw_tcp_conn_get_stats(struct iscsi_cls_conn * cls_conn,struct iscsi_stats * stats)903 iscsi_sw_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
904 			    struct iscsi_stats *stats)
905 {
906 	struct iscsi_conn *conn = cls_conn->dd_data;
907 	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
908 	struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
909 
910 	stats->custom_length = 3;
911 	strcpy(stats->custom[0].desc, "tx_sendpage_failures");
912 	stats->custom[0].value = tcp_sw_conn->sendpage_failures_cnt;
913 	strcpy(stats->custom[1].desc, "rx_discontiguous_hdr");
914 	stats->custom[1].value = tcp_sw_conn->discontiguous_hdr_cnt;
915 	strcpy(stats->custom[2].desc, "eh_abort_cnt");
916 	stats->custom[2].value = conn->eh_abort_cnt;
917 
918 	iscsi_tcp_conn_get_stats(cls_conn, stats);
919 }
920 
921 static struct iscsi_cls_session *
iscsi_sw_tcp_session_create(struct iscsi_endpoint * ep,uint16_t cmds_max,uint16_t qdepth,uint32_t initial_cmdsn)922 iscsi_sw_tcp_session_create(struct iscsi_endpoint *ep, uint16_t cmds_max,
923 			    uint16_t qdepth, uint32_t initial_cmdsn)
924 {
925 	struct iscsi_cls_session *cls_session;
926 	struct iscsi_session *session;
927 	struct iscsi_sw_tcp_host *tcp_sw_host;
928 	struct Scsi_Host *shost;
929 	int rc;
930 
931 	if (ep) {
932 		printk(KERN_ERR "iscsi_tcp: invalid ep %p.\n", ep);
933 		return NULL;
934 	}
935 
936 	shost = iscsi_host_alloc(&iscsi_sw_tcp_sht,
937 				 sizeof(struct iscsi_sw_tcp_host), 1);
938 	if (!shost)
939 		return NULL;
940 	shost->transportt = iscsi_sw_tcp_scsi_transport;
941 	shost->cmd_per_lun = qdepth;
942 	shost->max_lun = iscsi_max_lun;
943 	shost->max_id = 0;
944 	shost->max_channel = 0;
945 	shost->max_cmd_len = SCSI_MAX_VARLEN_CDB_SIZE;
946 	shost->dma_alignment = 0;
947 
948 	rc = iscsi_host_get_max_scsi_cmds(shost, cmds_max);
949 	if (rc < 0)
950 		goto free_host;
951 	shost->can_queue = rc;
952 
953 	if (iscsi_host_add(shost, NULL))
954 		goto free_host;
955 
956 	cls_session = iscsi_session_setup(&iscsi_sw_tcp_transport, shost,
957 					  cmds_max, 0,
958 					  sizeof(struct iscsi_tcp_task) +
959 					  sizeof(struct iscsi_sw_tcp_hdrbuf),
960 					  initial_cmdsn, 0);
961 	if (!cls_session)
962 		goto remove_host;
963 	session = cls_session->dd_data;
964 
965 	if (iscsi_tcp_r2tpool_alloc(session))
966 		goto remove_session;
967 
968 	/* We are now fully setup so expose the session to sysfs. */
969 	tcp_sw_host = iscsi_host_priv(shost);
970 	tcp_sw_host->session = session;
971 	return cls_session;
972 
973 remove_session:
974 	iscsi_session_teardown(cls_session);
975 remove_host:
976 	iscsi_host_remove(shost, false);
977 free_host:
978 	iscsi_host_free(shost);
979 	return NULL;
980 }
981 
iscsi_sw_tcp_session_destroy(struct iscsi_cls_session * cls_session)982 static void iscsi_sw_tcp_session_destroy(struct iscsi_cls_session *cls_session)
983 {
984 	struct Scsi_Host *shost = iscsi_session_to_shost(cls_session);
985 	struct iscsi_session *session = cls_session->dd_data;
986 
987 	if (WARN_ON_ONCE(session->leadconn))
988 		return;
989 
990 	iscsi_session_remove(cls_session);
991 	/*
992 	 * Our get_host_param needs to access the session, so remove the
993 	 * host from sysfs before freeing the session to make sure userspace
994 	 * is no longer accessing the callout.
995 	 */
996 	iscsi_host_remove(shost, false);
997 
998 	iscsi_tcp_r2tpool_free(cls_session->dd_data);
999 
1000 	iscsi_session_free(cls_session);
1001 	iscsi_host_free(shost);
1002 }
1003 
iscsi_sw_tcp_attr_is_visible(int param_type,int param)1004 static umode_t iscsi_sw_tcp_attr_is_visible(int param_type, int param)
1005 {
1006 	switch (param_type) {
1007 	case ISCSI_HOST_PARAM:
1008 		switch (param) {
1009 		case ISCSI_HOST_PARAM_NETDEV_NAME:
1010 		case ISCSI_HOST_PARAM_HWADDRESS:
1011 		case ISCSI_HOST_PARAM_IPADDRESS:
1012 		case ISCSI_HOST_PARAM_INITIATOR_NAME:
1013 			return S_IRUGO;
1014 		default:
1015 			return 0;
1016 		}
1017 	case ISCSI_PARAM:
1018 		switch (param) {
1019 		case ISCSI_PARAM_MAX_RECV_DLENGTH:
1020 		case ISCSI_PARAM_MAX_XMIT_DLENGTH:
1021 		case ISCSI_PARAM_HDRDGST_EN:
1022 		case ISCSI_PARAM_DATADGST_EN:
1023 		case ISCSI_PARAM_CONN_ADDRESS:
1024 		case ISCSI_PARAM_CONN_PORT:
1025 		case ISCSI_PARAM_LOCAL_PORT:
1026 		case ISCSI_PARAM_EXP_STATSN:
1027 		case ISCSI_PARAM_PERSISTENT_ADDRESS:
1028 		case ISCSI_PARAM_PERSISTENT_PORT:
1029 		case ISCSI_PARAM_PING_TMO:
1030 		case ISCSI_PARAM_RECV_TMO:
1031 		case ISCSI_PARAM_INITIAL_R2T_EN:
1032 		case ISCSI_PARAM_MAX_R2T:
1033 		case ISCSI_PARAM_IMM_DATA_EN:
1034 		case ISCSI_PARAM_FIRST_BURST:
1035 		case ISCSI_PARAM_MAX_BURST:
1036 		case ISCSI_PARAM_PDU_INORDER_EN:
1037 		case ISCSI_PARAM_DATASEQ_INORDER_EN:
1038 		case ISCSI_PARAM_ERL:
1039 		case ISCSI_PARAM_TARGET_NAME:
1040 		case ISCSI_PARAM_TPGT:
1041 		case ISCSI_PARAM_USERNAME:
1042 		case ISCSI_PARAM_PASSWORD:
1043 		case ISCSI_PARAM_USERNAME_IN:
1044 		case ISCSI_PARAM_PASSWORD_IN:
1045 		case ISCSI_PARAM_FAST_ABORT:
1046 		case ISCSI_PARAM_ABORT_TMO:
1047 		case ISCSI_PARAM_LU_RESET_TMO:
1048 		case ISCSI_PARAM_TGT_RESET_TMO:
1049 		case ISCSI_PARAM_IFACE_NAME:
1050 		case ISCSI_PARAM_INITIATOR_NAME:
1051 			return S_IRUGO;
1052 		default:
1053 			return 0;
1054 		}
1055 	}
1056 
1057 	return 0;
1058 }
1059 
iscsi_sw_tcp_device_configure(struct scsi_device * sdev,struct queue_limits * lim)1060 static int iscsi_sw_tcp_device_configure(struct scsi_device *sdev,
1061 		struct queue_limits *lim)
1062 {
1063 	struct iscsi_sw_tcp_host *tcp_sw_host = iscsi_host_priv(sdev->host);
1064 	struct iscsi_session *session = tcp_sw_host->session;
1065 	struct iscsi_conn *conn = session->leadconn;
1066 
1067 	if (conn->datadgst_en)
1068 		lim->features |= BLK_FEAT_STABLE_WRITES;
1069 	return 0;
1070 }
1071 
1072 static const struct scsi_host_template iscsi_sw_tcp_sht = {
1073 	.module			= THIS_MODULE,
1074 	.name			= "iSCSI Initiator over TCP/IP",
1075 	.queuecommand           = iscsi_queuecommand,
1076 	.change_queue_depth	= scsi_change_queue_depth,
1077 	.can_queue		= ISCSI_TOTAL_CMDS_MAX,
1078 	.sg_tablesize		= 4096,
1079 	.max_sectors		= 0xFFFF,
1080 	.cmd_per_lun		= ISCSI_DEF_CMD_PER_LUN,
1081 	.eh_timed_out		= iscsi_eh_cmd_timed_out,
1082 	.eh_abort_handler       = iscsi_eh_abort,
1083 	.eh_device_reset_handler= iscsi_eh_device_reset,
1084 	.eh_target_reset_handler = iscsi_eh_recover_target,
1085 	.dma_boundary		= PAGE_SIZE - 1,
1086 	.device_configure	= iscsi_sw_tcp_device_configure,
1087 	.proc_name		= "iscsi_tcp",
1088 	.this_id		= -1,
1089 	.track_queue_depth	= 1,
1090 	.cmd_size		= sizeof(struct iscsi_cmd),
1091 };
1092 
1093 static struct iscsi_transport iscsi_sw_tcp_transport = {
1094 	.owner			= THIS_MODULE,
1095 	.name			= "tcp",
1096 	.caps			= CAP_RECOVERY_L0 | CAP_MULTI_R2T | CAP_HDRDGST
1097 				  | CAP_DATADGST,
1098 	/* session management */
1099 	.create_session		= iscsi_sw_tcp_session_create,
1100 	.destroy_session	= iscsi_sw_tcp_session_destroy,
1101 	/* connection management */
1102 	.create_conn		= iscsi_sw_tcp_conn_create,
1103 	.bind_conn		= iscsi_sw_tcp_conn_bind,
1104 	.destroy_conn		= iscsi_sw_tcp_conn_destroy,
1105 	.attr_is_visible	= iscsi_sw_tcp_attr_is_visible,
1106 	.set_param		= iscsi_sw_tcp_conn_set_param,
1107 	.get_conn_param		= iscsi_sw_tcp_conn_get_param,
1108 	.get_session_param	= iscsi_session_get_param,
1109 	.start_conn		= iscsi_conn_start,
1110 	.stop_conn		= iscsi_sw_tcp_conn_stop,
1111 	/* iscsi host params */
1112 	.get_host_param		= iscsi_sw_tcp_host_get_param,
1113 	.set_host_param		= iscsi_host_set_param,
1114 	/* IO */
1115 	.send_pdu		= iscsi_conn_send_pdu,
1116 	.get_stats		= iscsi_sw_tcp_conn_get_stats,
1117 	/* iscsi task/cmd helpers */
1118 	.init_task		= iscsi_tcp_task_init,
1119 	.xmit_task		= iscsi_tcp_task_xmit,
1120 	.cleanup_task		= iscsi_tcp_cleanup_task,
1121 	/* low level pdu helpers */
1122 	.xmit_pdu		= iscsi_sw_tcp_pdu_xmit,
1123 	.init_pdu		= iscsi_sw_tcp_pdu_init,
1124 	.alloc_pdu		= iscsi_sw_tcp_pdu_alloc,
1125 	/* recovery */
1126 	.session_recovery_timedout = iscsi_session_recovery_timedout,
1127 };
1128 
iscsi_sw_tcp_init(void)1129 static int __init iscsi_sw_tcp_init(void)
1130 {
1131 	if (iscsi_max_lun < 1) {
1132 		printk(KERN_ERR "iscsi_tcp: Invalid max_lun value of %u\n",
1133 		       iscsi_max_lun);
1134 		return -EINVAL;
1135 	}
1136 
1137 	iscsi_sw_tcp_scsi_transport = iscsi_register_transport(
1138 						&iscsi_sw_tcp_transport);
1139 	if (!iscsi_sw_tcp_scsi_transport)
1140 		return -ENODEV;
1141 
1142 	return 0;
1143 }
1144 
iscsi_sw_tcp_exit(void)1145 static void __exit iscsi_sw_tcp_exit(void)
1146 {
1147 	iscsi_unregister_transport(&iscsi_sw_tcp_transport);
1148 }
1149 
1150 module_init(iscsi_sw_tcp_init);
1151 module_exit(iscsi_sw_tcp_exit);
1152