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