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
40 #include "iscsi_tcp.h"
41
42 MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, "
43 "Dmitry Yusupov <dmitry_yus@yahoo.com>, "
44 "Alex Aizman <itn780@yahoo.com>");
45 MODULE_DESCRIPTION("iSCSI/TCP data-path");
46 MODULE_LICENSE("GPL");
47
48 static struct scsi_transport_template *iscsi_sw_tcp_scsi_transport;
49 static struct scsi_host_template iscsi_sw_tcp_sht;
50 static struct iscsi_transport iscsi_sw_tcp_transport;
51
52 static unsigned int iscsi_max_lun = ~0;
53 module_param_named(max_lun, iscsi_max_lun, uint, S_IRUGO);
54
55 static bool iscsi_recv_from_iscsi_q;
56 module_param_named(recv_from_iscsi_q, iscsi_recv_from_iscsi_q, bool, 0644);
57 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.");
58
59 static int iscsi_sw_tcp_dbg;
60 module_param_named(debug_iscsi_tcp, iscsi_sw_tcp_dbg, int,
61 S_IRUGO | S_IWUSR);
62 MODULE_PARM_DESC(debug_iscsi_tcp, "Turn on debugging for iscsi_tcp module "
63 "Set to 1 to turn on, and zero to turn off. Default is off.");
64
65 #define ISCSI_SW_TCP_DBG(_conn, dbg_fmt, arg...) \
66 do { \
67 if (iscsi_sw_tcp_dbg) \
68 iscsi_conn_printk(KERN_INFO, _conn, \
69 "%s " dbg_fmt, \
70 __func__, ##arg); \
71 iscsi_dbg_trace(trace_iscsi_dbg_sw_tcp, \
72 &(_conn)->cls_conn->dev, \
73 "%s " dbg_fmt, __func__, ##arg);\
74 } while (0);
75
76
77 /**
78 * iscsi_sw_tcp_recv - TCP receive in sendfile fashion
79 * @rd_desc: read descriptor
80 * @skb: socket buffer
81 * @offset: offset in skb
82 * @len: skb->len - offset
83 */
iscsi_sw_tcp_recv(read_descriptor_t * rd_desc,struct sk_buff * skb,unsigned int offset,size_t len)84 static int iscsi_sw_tcp_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
85 unsigned int offset, size_t len)
86 {
87 struct iscsi_conn *conn = rd_desc->arg.data;
88 unsigned int consumed, total_consumed = 0;
89 int status;
90
91 ISCSI_SW_TCP_DBG(conn, "in %d bytes\n", skb->len - offset);
92
93 do {
94 status = 0;
95 consumed = iscsi_tcp_recv_skb(conn, skb, offset, 0, &status);
96 offset += consumed;
97 total_consumed += consumed;
98 } while (consumed != 0 && status != ISCSI_TCP_SKB_DONE);
99
100 ISCSI_SW_TCP_DBG(conn, "read %d bytes status %d\n",
101 skb->len - offset, status);
102 return total_consumed;
103 }
104
105 /**
106 * iscsi_sw_sk_state_check - check socket state
107 * @sk: socket
108 *
109 * If the socket is in CLOSE or CLOSE_WAIT we should
110 * not close the connection if there is still some
111 * data pending.
112 *
113 * Must be called with sk_callback_lock.
114 */
iscsi_sw_sk_state_check(struct sock * sk)115 static inline int iscsi_sw_sk_state_check(struct sock *sk)
116 {
117 struct iscsi_conn *conn = sk->sk_user_data;
118
119 if ((sk->sk_state == TCP_CLOSE_WAIT || sk->sk_state == TCP_CLOSE) &&
120 (conn->session->state != ISCSI_STATE_LOGGING_OUT) &&
121 !atomic_read(&sk->sk_rmem_alloc)) {
122 ISCSI_SW_TCP_DBG(conn, "TCP_CLOSE|TCP_CLOSE_WAIT\n");
123 iscsi_conn_failure(conn, ISCSI_ERR_TCP_CONN_CLOSE);
124 return -ECONNRESET;
125 }
126 return 0;
127 }
128
iscsi_sw_tcp_recv_data(struct iscsi_conn * conn)129 static void iscsi_sw_tcp_recv_data(struct iscsi_conn *conn)
130 {
131 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
132 struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
133 struct sock *sk = tcp_sw_conn->sock->sk;
134 read_descriptor_t rd_desc;
135
136 /*
137 * Use rd_desc to pass 'conn' to iscsi_tcp_recv.
138 * We set count to 1 because we want the network layer to
139 * hand us all the skbs that are available. iscsi_tcp_recv
140 * handled pdus that cross buffers or pdus that still need data.
141 */
142 rd_desc.arg.data = conn;
143 rd_desc.count = 1;
144
145 tcp_read_sock(sk, &rd_desc, iscsi_sw_tcp_recv);
146
147 /* If we had to (atomically) map a highmem page,
148 * unmap it now. */
149 iscsi_tcp_segment_unmap(&tcp_conn->in.segment);
150
151 iscsi_sw_sk_state_check(sk);
152 }
153
iscsi_sw_tcp_recv_data_work(struct work_struct * work)154 static void iscsi_sw_tcp_recv_data_work(struct work_struct *work)
155 {
156 struct iscsi_conn *conn = container_of(work, struct iscsi_conn,
157 recvwork);
158 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
159 struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
160 struct sock *sk = tcp_sw_conn->sock->sk;
161
162 lock_sock(sk);
163 iscsi_sw_tcp_recv_data(conn);
164 release_sock(sk);
165 }
166
iscsi_sw_tcp_data_ready(struct sock * sk)167 static void iscsi_sw_tcp_data_ready(struct sock *sk)
168 {
169 struct iscsi_sw_tcp_conn *tcp_sw_conn;
170 struct iscsi_tcp_conn *tcp_conn;
171 struct iscsi_conn *conn;
172
173 read_lock_bh(&sk->sk_callback_lock);
174 conn = sk->sk_user_data;
175 if (!conn) {
176 read_unlock_bh(&sk->sk_callback_lock);
177 return;
178 }
179 tcp_conn = conn->dd_data;
180 tcp_sw_conn = tcp_conn->dd_data;
181
182 if (tcp_sw_conn->queue_recv)
183 iscsi_conn_queue_recv(conn);
184 else
185 iscsi_sw_tcp_recv_data(conn);
186 read_unlock_bh(&sk->sk_callback_lock);
187 }
188
iscsi_sw_tcp_state_change(struct sock * sk)189 static void iscsi_sw_tcp_state_change(struct sock *sk)
190 {
191 struct iscsi_tcp_conn *tcp_conn;
192 struct iscsi_sw_tcp_conn *tcp_sw_conn;
193 struct iscsi_conn *conn;
194 void (*old_state_change)(struct sock *);
195
196 read_lock_bh(&sk->sk_callback_lock);
197 conn = sk->sk_user_data;
198 if (!conn) {
199 read_unlock_bh(&sk->sk_callback_lock);
200 return;
201 }
202
203 iscsi_sw_sk_state_check(sk);
204
205 tcp_conn = conn->dd_data;
206 tcp_sw_conn = tcp_conn->dd_data;
207 old_state_change = tcp_sw_conn->old_state_change;
208
209 read_unlock_bh(&sk->sk_callback_lock);
210
211 old_state_change(sk);
212 }
213
214 /**
215 * iscsi_sw_tcp_write_space - Called when more output buffer space is available
216 * @sk: socket space is available for
217 **/
iscsi_sw_tcp_write_space(struct sock * sk)218 static void iscsi_sw_tcp_write_space(struct sock *sk)
219 {
220 struct iscsi_conn *conn;
221 struct iscsi_tcp_conn *tcp_conn;
222 struct iscsi_sw_tcp_conn *tcp_sw_conn;
223 void (*old_write_space)(struct sock *);
224
225 read_lock_bh(&sk->sk_callback_lock);
226 conn = sk->sk_user_data;
227 if (!conn) {
228 read_unlock_bh(&sk->sk_callback_lock);
229 return;
230 }
231
232 tcp_conn = conn->dd_data;
233 tcp_sw_conn = tcp_conn->dd_data;
234 old_write_space = tcp_sw_conn->old_write_space;
235 read_unlock_bh(&sk->sk_callback_lock);
236
237 old_write_space(sk);
238
239 ISCSI_SW_TCP_DBG(conn, "iscsi_write_space\n");
240 iscsi_conn_queue_xmit(conn);
241 }
242
iscsi_sw_tcp_conn_set_callbacks(struct iscsi_conn * conn)243 static void iscsi_sw_tcp_conn_set_callbacks(struct iscsi_conn *conn)
244 {
245 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
246 struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
247 struct sock *sk = tcp_sw_conn->sock->sk;
248
249 /* assign new callbacks */
250 write_lock_bh(&sk->sk_callback_lock);
251 sk->sk_user_data = conn;
252 tcp_sw_conn->old_data_ready = sk->sk_data_ready;
253 tcp_sw_conn->old_state_change = sk->sk_state_change;
254 tcp_sw_conn->old_write_space = sk->sk_write_space;
255 sk->sk_data_ready = iscsi_sw_tcp_data_ready;
256 sk->sk_state_change = iscsi_sw_tcp_state_change;
257 sk->sk_write_space = iscsi_sw_tcp_write_space;
258 write_unlock_bh(&sk->sk_callback_lock);
259 }
260
261 static void
iscsi_sw_tcp_conn_restore_callbacks(struct iscsi_conn * conn)262 iscsi_sw_tcp_conn_restore_callbacks(struct iscsi_conn *conn)
263 {
264 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
265 struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
266 struct sock *sk = tcp_sw_conn->sock->sk;
267
268 /* restore socket callbacks, see also: iscsi_conn_set_callbacks() */
269 write_lock_bh(&sk->sk_callback_lock);
270 sk->sk_user_data = NULL;
271 sk->sk_data_ready = tcp_sw_conn->old_data_ready;
272 sk->sk_state_change = tcp_sw_conn->old_state_change;
273 sk->sk_write_space = tcp_sw_conn->old_write_space;
274 sk->sk_no_check_tx = 0;
275 write_unlock_bh(&sk->sk_callback_lock);
276 }
277
278 /**
279 * iscsi_sw_tcp_xmit_segment - transmit segment
280 * @tcp_conn: the iSCSI TCP connection
281 * @segment: the buffer to transmnit
282 *
283 * This function transmits as much of the buffer as
284 * the network layer will accept, and returns the number of
285 * bytes transmitted.
286 *
287 * If CRC hashing is enabled, the function will compute the
288 * hash as it goes. When the entire segment has been transmitted,
289 * it will retrieve the hash value and send it as well.
290 */
iscsi_sw_tcp_xmit_segment(struct iscsi_tcp_conn * tcp_conn,struct iscsi_segment * segment)291 static int iscsi_sw_tcp_xmit_segment(struct iscsi_tcp_conn *tcp_conn,
292 struct iscsi_segment *segment)
293 {
294 struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
295 struct socket *sk = tcp_sw_conn->sock;
296 unsigned int copied = 0;
297 int r = 0;
298
299 while (!iscsi_tcp_segment_done(tcp_conn, segment, 0, r)) {
300 struct scatterlist *sg;
301 unsigned int offset, copy;
302 int flags = 0;
303
304 r = 0;
305 offset = segment->copied;
306 copy = segment->size - offset;
307
308 if (segment->total_copied + segment->size < segment->total_size)
309 flags |= MSG_MORE;
310
311 if (tcp_sw_conn->queue_recv)
312 flags |= MSG_DONTWAIT;
313
314 /* Use sendpage if we can; else fall back to sendmsg */
315 if (!segment->data) {
316 sg = segment->sg;
317 offset += segment->sg_offset + sg->offset;
318 r = tcp_sw_conn->sendpage(sk, sg_page(sg), offset,
319 copy, flags);
320 } else {
321 struct msghdr msg = { .msg_flags = flags };
322 struct kvec iov = {
323 .iov_base = segment->data + offset,
324 .iov_len = copy
325 };
326
327 r = kernel_sendmsg(sk, &msg, &iov, 1, copy);
328 }
329
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 = iscsi_conn_bind(cls_session, cls_conn, is_leading);
728 if (err)
729 goto free_socket;
730
731 mutex_lock(&tcp_sw_conn->sock_lock);
732 /* bind iSCSI connection and socket */
733 tcp_sw_conn->sock = sock;
734 mutex_unlock(&tcp_sw_conn->sock_lock);
735
736 /* setup Socket parameters */
737 sk = sock->sk;
738 sk->sk_reuse = SK_CAN_REUSE;
739 sk->sk_sndtimeo = 15 * HZ; /* FIXME: make it configurable */
740 sk->sk_allocation = GFP_ATOMIC;
741 sk_set_memalloc(sk);
742 sock_no_linger(sk);
743
744 iscsi_sw_tcp_conn_set_callbacks(conn);
745 tcp_sw_conn->sendpage = tcp_sw_conn->sock->ops->sendpage;
746 /*
747 * set receive state machine into initial state
748 */
749 iscsi_tcp_hdr_recv_prep(tcp_conn);
750 return 0;
751
752 free_socket:
753 sockfd_put(sock);
754 return err;
755 }
756
iscsi_sw_tcp_conn_set_param(struct iscsi_cls_conn * cls_conn,enum iscsi_param param,char * buf,int buflen)757 static int iscsi_sw_tcp_conn_set_param(struct iscsi_cls_conn *cls_conn,
758 enum iscsi_param param, char *buf,
759 int buflen)
760 {
761 struct iscsi_conn *conn = cls_conn->dd_data;
762 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
763 struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
764
765 switch(param) {
766 case ISCSI_PARAM_HDRDGST_EN:
767 iscsi_set_param(cls_conn, param, buf, buflen);
768 break;
769 case ISCSI_PARAM_DATADGST_EN:
770 mutex_lock(&tcp_sw_conn->sock_lock);
771 if (!tcp_sw_conn->sock) {
772 mutex_unlock(&tcp_sw_conn->sock_lock);
773 return -ENOTCONN;
774 }
775 iscsi_set_param(cls_conn, param, buf, buflen);
776 tcp_sw_conn->sendpage = conn->datadgst_en ?
777 sock_no_sendpage : tcp_sw_conn->sock->ops->sendpage;
778 mutex_unlock(&tcp_sw_conn->sock_lock);
779 break;
780 case ISCSI_PARAM_MAX_R2T:
781 return iscsi_tcp_set_max_r2t(conn, buf);
782 default:
783 return iscsi_set_param(cls_conn, param, buf, buflen);
784 }
785
786 return 0;
787 }
788
iscsi_sw_tcp_conn_get_param(struct iscsi_cls_conn * cls_conn,enum iscsi_param param,char * buf)789 static int iscsi_sw_tcp_conn_get_param(struct iscsi_cls_conn *cls_conn,
790 enum iscsi_param param, char *buf)
791 {
792 struct iscsi_conn *conn = cls_conn->dd_data;
793 struct iscsi_sw_tcp_conn *tcp_sw_conn;
794 struct iscsi_tcp_conn *tcp_conn;
795 struct sockaddr_in6 addr;
796 struct socket *sock;
797 int rc;
798
799 switch(param) {
800 case ISCSI_PARAM_CONN_PORT:
801 case ISCSI_PARAM_CONN_ADDRESS:
802 case ISCSI_PARAM_LOCAL_PORT:
803 spin_lock_bh(&conn->session->frwd_lock);
804 if (!conn->session->leadconn) {
805 spin_unlock_bh(&conn->session->frwd_lock);
806 return -ENOTCONN;
807 }
808 /*
809 * The conn has been setup and bound, so just grab a ref
810 * incase a destroy runs while we are in the net layer.
811 */
812 iscsi_get_conn(conn->cls_conn);
813 spin_unlock_bh(&conn->session->frwd_lock);
814
815 tcp_conn = conn->dd_data;
816 tcp_sw_conn = tcp_conn->dd_data;
817
818 mutex_lock(&tcp_sw_conn->sock_lock);
819 sock = tcp_sw_conn->sock;
820 if (!sock) {
821 rc = -ENOTCONN;
822 goto sock_unlock;
823 }
824
825 if (param == ISCSI_PARAM_LOCAL_PORT)
826 rc = kernel_getsockname(sock,
827 (struct sockaddr *)&addr);
828 else
829 rc = kernel_getpeername(sock,
830 (struct sockaddr *)&addr);
831 sock_unlock:
832 mutex_unlock(&tcp_sw_conn->sock_lock);
833 iscsi_put_conn(conn->cls_conn);
834 if (rc < 0)
835 return rc;
836
837 return iscsi_conn_get_addr_param((struct sockaddr_storage *)
838 &addr, param, buf);
839 default:
840 return iscsi_conn_get_param(cls_conn, param, buf);
841 }
842
843 return 0;
844 }
845
iscsi_sw_tcp_host_get_param(struct Scsi_Host * shost,enum iscsi_host_param param,char * buf)846 static int iscsi_sw_tcp_host_get_param(struct Scsi_Host *shost,
847 enum iscsi_host_param param, char *buf)
848 {
849 struct iscsi_sw_tcp_host *tcp_sw_host = iscsi_host_priv(shost);
850 struct iscsi_session *session;
851 struct iscsi_conn *conn;
852 struct iscsi_tcp_conn *tcp_conn;
853 struct iscsi_sw_tcp_conn *tcp_sw_conn;
854 struct sockaddr_in6 addr;
855 struct socket *sock;
856 int rc;
857
858 switch (param) {
859 case ISCSI_HOST_PARAM_IPADDRESS:
860 session = tcp_sw_host->session;
861 if (!session)
862 return -ENOTCONN;
863
864 spin_lock_bh(&session->frwd_lock);
865 conn = session->leadconn;
866 if (!conn) {
867 spin_unlock_bh(&session->frwd_lock);
868 return -ENOTCONN;
869 }
870 tcp_conn = conn->dd_data;
871 tcp_sw_conn = tcp_conn->dd_data;
872 /*
873 * The conn has been setup and bound, so just grab a ref
874 * incase a destroy runs while we are in the net layer.
875 */
876 iscsi_get_conn(conn->cls_conn);
877 spin_unlock_bh(&session->frwd_lock);
878
879 mutex_lock(&tcp_sw_conn->sock_lock);
880 sock = tcp_sw_conn->sock;
881 if (!sock)
882 rc = -ENOTCONN;
883 else
884 rc = kernel_getsockname(sock, (struct sockaddr *)&addr);
885 mutex_unlock(&tcp_sw_conn->sock_lock);
886 iscsi_put_conn(conn->cls_conn);
887 if (rc < 0)
888 return rc;
889
890 return iscsi_conn_get_addr_param((struct sockaddr_storage *)
891 &addr,
892 (enum iscsi_param)param, buf);
893 default:
894 return iscsi_host_get_param(shost, param, buf);
895 }
896
897 return 0;
898 }
899
900 static void
iscsi_sw_tcp_conn_get_stats(struct iscsi_cls_conn * cls_conn,struct iscsi_stats * stats)901 iscsi_sw_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
902 struct iscsi_stats *stats)
903 {
904 struct iscsi_conn *conn = cls_conn->dd_data;
905 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
906 struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
907
908 stats->custom_length = 3;
909 strcpy(stats->custom[0].desc, "tx_sendpage_failures");
910 stats->custom[0].value = tcp_sw_conn->sendpage_failures_cnt;
911 strcpy(stats->custom[1].desc, "rx_discontiguous_hdr");
912 stats->custom[1].value = tcp_sw_conn->discontiguous_hdr_cnt;
913 strcpy(stats->custom[2].desc, "eh_abort_cnt");
914 stats->custom[2].value = conn->eh_abort_cnt;
915
916 iscsi_tcp_conn_get_stats(cls_conn, stats);
917 }
918
919 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)920 iscsi_sw_tcp_session_create(struct iscsi_endpoint *ep, uint16_t cmds_max,
921 uint16_t qdepth, uint32_t initial_cmdsn)
922 {
923 struct iscsi_cls_session *cls_session;
924 struct iscsi_session *session;
925 struct iscsi_sw_tcp_host *tcp_sw_host;
926 struct Scsi_Host *shost;
927 int rc;
928
929 if (ep) {
930 printk(KERN_ERR "iscsi_tcp: invalid ep %p.\n", ep);
931 return NULL;
932 }
933
934 shost = iscsi_host_alloc(&iscsi_sw_tcp_sht,
935 sizeof(struct iscsi_sw_tcp_host), 1);
936 if (!shost)
937 return NULL;
938 shost->transportt = iscsi_sw_tcp_scsi_transport;
939 shost->cmd_per_lun = qdepth;
940 shost->max_lun = iscsi_max_lun;
941 shost->max_id = 0;
942 shost->max_channel = 0;
943 shost->max_cmd_len = SCSI_MAX_VARLEN_CDB_SIZE;
944
945 rc = iscsi_host_get_max_scsi_cmds(shost, cmds_max);
946 if (rc < 0)
947 goto free_host;
948 shost->can_queue = rc;
949
950 if (iscsi_host_add(shost, NULL))
951 goto free_host;
952
953 cls_session = iscsi_session_setup(&iscsi_sw_tcp_transport, shost,
954 cmds_max, 0,
955 sizeof(struct iscsi_tcp_task) +
956 sizeof(struct iscsi_sw_tcp_hdrbuf),
957 initial_cmdsn, 0);
958 if (!cls_session)
959 goto remove_host;
960 session = cls_session->dd_data;
961
962 if (iscsi_tcp_r2tpool_alloc(session))
963 goto remove_session;
964
965 /* We are now fully setup so expose the session to sysfs. */
966 tcp_sw_host = iscsi_host_priv(shost);
967 tcp_sw_host->session = session;
968 return cls_session;
969
970 remove_session:
971 iscsi_session_teardown(cls_session);
972 remove_host:
973 iscsi_host_remove(shost, false);
974 free_host:
975 iscsi_host_free(shost);
976 return NULL;
977 }
978
iscsi_sw_tcp_session_destroy(struct iscsi_cls_session * cls_session)979 static void iscsi_sw_tcp_session_destroy(struct iscsi_cls_session *cls_session)
980 {
981 struct Scsi_Host *shost = iscsi_session_to_shost(cls_session);
982 struct iscsi_session *session = cls_session->dd_data;
983
984 if (WARN_ON_ONCE(session->leadconn))
985 return;
986
987 iscsi_session_remove(cls_session);
988 /*
989 * Our get_host_param needs to access the session, so remove the
990 * host from sysfs before freeing the session to make sure userspace
991 * is no longer accessing the callout.
992 */
993 iscsi_host_remove(shost, false);
994
995 iscsi_tcp_r2tpool_free(cls_session->dd_data);
996
997 iscsi_session_free(cls_session);
998 iscsi_host_free(shost);
999 }
1000
iscsi_sw_tcp_attr_is_visible(int param_type,int param)1001 static umode_t iscsi_sw_tcp_attr_is_visible(int param_type, int param)
1002 {
1003 switch (param_type) {
1004 case ISCSI_HOST_PARAM:
1005 switch (param) {
1006 case ISCSI_HOST_PARAM_NETDEV_NAME:
1007 case ISCSI_HOST_PARAM_HWADDRESS:
1008 case ISCSI_HOST_PARAM_IPADDRESS:
1009 case ISCSI_HOST_PARAM_INITIATOR_NAME:
1010 return S_IRUGO;
1011 default:
1012 return 0;
1013 }
1014 case ISCSI_PARAM:
1015 switch (param) {
1016 case ISCSI_PARAM_MAX_RECV_DLENGTH:
1017 case ISCSI_PARAM_MAX_XMIT_DLENGTH:
1018 case ISCSI_PARAM_HDRDGST_EN:
1019 case ISCSI_PARAM_DATADGST_EN:
1020 case ISCSI_PARAM_CONN_ADDRESS:
1021 case ISCSI_PARAM_CONN_PORT:
1022 case ISCSI_PARAM_LOCAL_PORT:
1023 case ISCSI_PARAM_EXP_STATSN:
1024 case ISCSI_PARAM_PERSISTENT_ADDRESS:
1025 case ISCSI_PARAM_PERSISTENT_PORT:
1026 case ISCSI_PARAM_PING_TMO:
1027 case ISCSI_PARAM_RECV_TMO:
1028 case ISCSI_PARAM_INITIAL_R2T_EN:
1029 case ISCSI_PARAM_MAX_R2T:
1030 case ISCSI_PARAM_IMM_DATA_EN:
1031 case ISCSI_PARAM_FIRST_BURST:
1032 case ISCSI_PARAM_MAX_BURST:
1033 case ISCSI_PARAM_PDU_INORDER_EN:
1034 case ISCSI_PARAM_DATASEQ_INORDER_EN:
1035 case ISCSI_PARAM_ERL:
1036 case ISCSI_PARAM_TARGET_NAME:
1037 case ISCSI_PARAM_TPGT:
1038 case ISCSI_PARAM_USERNAME:
1039 case ISCSI_PARAM_PASSWORD:
1040 case ISCSI_PARAM_USERNAME_IN:
1041 case ISCSI_PARAM_PASSWORD_IN:
1042 case ISCSI_PARAM_FAST_ABORT:
1043 case ISCSI_PARAM_ABORT_TMO:
1044 case ISCSI_PARAM_LU_RESET_TMO:
1045 case ISCSI_PARAM_TGT_RESET_TMO:
1046 case ISCSI_PARAM_IFACE_NAME:
1047 case ISCSI_PARAM_INITIATOR_NAME:
1048 return S_IRUGO;
1049 default:
1050 return 0;
1051 }
1052 }
1053
1054 return 0;
1055 }
1056
iscsi_sw_tcp_slave_configure(struct scsi_device * sdev)1057 static int iscsi_sw_tcp_slave_configure(struct scsi_device *sdev)
1058 {
1059 struct iscsi_sw_tcp_host *tcp_sw_host = iscsi_host_priv(sdev->host);
1060 struct iscsi_session *session = tcp_sw_host->session;
1061 struct iscsi_conn *conn = session->leadconn;
1062
1063 if (conn->datadgst_en)
1064 blk_queue_flag_set(QUEUE_FLAG_STABLE_WRITES,
1065 sdev->request_queue);
1066 blk_queue_dma_alignment(sdev->request_queue, 0);
1067 return 0;
1068 }
1069
1070 static struct scsi_host_template iscsi_sw_tcp_sht = {
1071 .module = THIS_MODULE,
1072 .name = "iSCSI Initiator over TCP/IP",
1073 .queuecommand = iscsi_queuecommand,
1074 .change_queue_depth = scsi_change_queue_depth,
1075 .can_queue = ISCSI_TOTAL_CMDS_MAX,
1076 .sg_tablesize = 4096,
1077 .max_sectors = 0xFFFF,
1078 .cmd_per_lun = ISCSI_DEF_CMD_PER_LUN,
1079 .eh_timed_out = iscsi_eh_cmd_timed_out,
1080 .eh_abort_handler = iscsi_eh_abort,
1081 .eh_device_reset_handler= iscsi_eh_device_reset,
1082 .eh_target_reset_handler = iscsi_eh_recover_target,
1083 .dma_boundary = PAGE_SIZE - 1,
1084 .slave_configure = iscsi_sw_tcp_slave_configure,
1085 .target_alloc = iscsi_target_alloc,
1086 .proc_name = "iscsi_tcp",
1087 .this_id = -1,
1088 .track_queue_depth = 1,
1089 };
1090
1091 static struct iscsi_transport iscsi_sw_tcp_transport = {
1092 .owner = THIS_MODULE,
1093 .name = "tcp",
1094 .caps = CAP_RECOVERY_L0 | CAP_MULTI_R2T | CAP_HDRDGST
1095 | CAP_DATADGST,
1096 /* session management */
1097 .create_session = iscsi_sw_tcp_session_create,
1098 .destroy_session = iscsi_sw_tcp_session_destroy,
1099 /* connection management */
1100 .create_conn = iscsi_sw_tcp_conn_create,
1101 .bind_conn = iscsi_sw_tcp_conn_bind,
1102 .destroy_conn = iscsi_sw_tcp_conn_destroy,
1103 .attr_is_visible = iscsi_sw_tcp_attr_is_visible,
1104 .set_param = iscsi_sw_tcp_conn_set_param,
1105 .get_conn_param = iscsi_sw_tcp_conn_get_param,
1106 .get_session_param = iscsi_session_get_param,
1107 .start_conn = iscsi_conn_start,
1108 .stop_conn = iscsi_sw_tcp_conn_stop,
1109 /* iscsi host params */
1110 .get_host_param = iscsi_sw_tcp_host_get_param,
1111 .set_host_param = iscsi_host_set_param,
1112 /* IO */
1113 .send_pdu = iscsi_conn_send_pdu,
1114 .get_stats = iscsi_sw_tcp_conn_get_stats,
1115 /* iscsi task/cmd helpers */
1116 .init_task = iscsi_tcp_task_init,
1117 .xmit_task = iscsi_tcp_task_xmit,
1118 .cleanup_task = iscsi_tcp_cleanup_task,
1119 /* low level pdu helpers */
1120 .xmit_pdu = iscsi_sw_tcp_pdu_xmit,
1121 .init_pdu = iscsi_sw_tcp_pdu_init,
1122 .alloc_pdu = iscsi_sw_tcp_pdu_alloc,
1123 /* recovery */
1124 .session_recovery_timedout = iscsi_session_recovery_timedout,
1125 };
1126
iscsi_sw_tcp_init(void)1127 static int __init iscsi_sw_tcp_init(void)
1128 {
1129 if (iscsi_max_lun < 1) {
1130 printk(KERN_ERR "iscsi_tcp: Invalid max_lun value of %u\n",
1131 iscsi_max_lun);
1132 return -EINVAL;
1133 }
1134
1135 iscsi_sw_tcp_scsi_transport = iscsi_register_transport(
1136 &iscsi_sw_tcp_transport);
1137 if (!iscsi_sw_tcp_scsi_transport)
1138 return -ENODEV;
1139
1140 return 0;
1141 }
1142
iscsi_sw_tcp_exit(void)1143 static void __exit iscsi_sw_tcp_exit(void)
1144 {
1145 iscsi_unregister_transport(&iscsi_sw_tcp_transport);
1146 }
1147
1148 module_init(iscsi_sw_tcp_init);
1149 module_exit(iscsi_sw_tcp_exit);
1150