xref: /linux/drivers/scsi/scsi_transport_iscsi.c (revision c537b994505099b7197e7d3125b942ecbcc51eb6)
1 /*
2  * iSCSI transport class definitions
3  *
4  * Copyright (C) IBM Corporation, 2004
5  * Copyright (C) Mike Christie, 2004 - 2005
6  * Copyright (C) Dmitry Yusupov, 2004 - 2005
7  * Copyright (C) Alex Aizman, 2004 - 2005
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  * GNU General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License
20  * along with this program; if not, write to the Free Software
21  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
22  */
23 #include <linux/module.h>
24 #include <linux/mutex.h>
25 #include <net/tcp.h>
26 #include <scsi/scsi.h>
27 #include <scsi/scsi_host.h>
28 #include <scsi/scsi_device.h>
29 #include <scsi/scsi_transport.h>
30 #include <scsi/scsi_transport_iscsi.h>
31 #include <scsi/iscsi_if.h>
32 
33 #define ISCSI_SESSION_ATTRS 11
34 #define ISCSI_CONN_ATTRS 11
35 #define ISCSI_HOST_ATTRS 0
36 #define ISCSI_TRANSPORT_VERSION "2.0-724"
37 
38 struct iscsi_internal {
39 	int daemon_pid;
40 	struct scsi_transport_template t;
41 	struct iscsi_transport *iscsi_transport;
42 	struct list_head list;
43 	struct class_device cdev;
44 
45 	struct class_device_attribute *host_attrs[ISCSI_HOST_ATTRS + 1];
46 	struct transport_container conn_cont;
47 	struct class_device_attribute *conn_attrs[ISCSI_CONN_ATTRS + 1];
48 	struct transport_container session_cont;
49 	struct class_device_attribute *session_attrs[ISCSI_SESSION_ATTRS + 1];
50 };
51 
52 static int iscsi_session_nr;	/* sysfs session id for next new session */
53 
54 /*
55  * list of registered transports and lock that must
56  * be held while accessing list. The iscsi_transport_lock must
57  * be acquired after the rx_queue_mutex.
58  */
59 static LIST_HEAD(iscsi_transports);
60 static DEFINE_SPINLOCK(iscsi_transport_lock);
61 
62 #define to_iscsi_internal(tmpl) \
63 	container_of(tmpl, struct iscsi_internal, t)
64 
65 #define cdev_to_iscsi_internal(_cdev) \
66 	container_of(_cdev, struct iscsi_internal, cdev)
67 
68 static void iscsi_transport_release(struct class_device *cdev)
69 {
70 	struct iscsi_internal *priv = cdev_to_iscsi_internal(cdev);
71 	kfree(priv);
72 }
73 
74 /*
75  * iscsi_transport_class represents the iscsi_transports that are
76  * registered.
77  */
78 static struct class iscsi_transport_class = {
79 	.name = "iscsi_transport",
80 	.release = iscsi_transport_release,
81 };
82 
83 static ssize_t
84 show_transport_handle(struct class_device *cdev, char *buf)
85 {
86 	struct iscsi_internal *priv = cdev_to_iscsi_internal(cdev);
87 	return sprintf(buf, "%llu\n", (unsigned long long)iscsi_handle(priv->iscsi_transport));
88 }
89 static CLASS_DEVICE_ATTR(handle, S_IRUGO, show_transport_handle, NULL);
90 
91 #define show_transport_attr(name, format)				\
92 static ssize_t								\
93 show_transport_##name(struct class_device *cdev, char *buf)		\
94 {									\
95 	struct iscsi_internal *priv = cdev_to_iscsi_internal(cdev);	\
96 	return sprintf(buf, format"\n", priv->iscsi_transport->name);	\
97 }									\
98 static CLASS_DEVICE_ATTR(name, S_IRUGO, show_transport_##name, NULL);
99 
100 show_transport_attr(caps, "0x%x");
101 show_transport_attr(max_lun, "%d");
102 show_transport_attr(max_conn, "%d");
103 show_transport_attr(max_cmd_len, "%d");
104 
105 static struct attribute *iscsi_transport_attrs[] = {
106 	&class_device_attr_handle.attr,
107 	&class_device_attr_caps.attr,
108 	&class_device_attr_max_lun.attr,
109 	&class_device_attr_max_conn.attr,
110 	&class_device_attr_max_cmd_len.attr,
111 	NULL,
112 };
113 
114 static struct attribute_group iscsi_transport_group = {
115 	.attrs = iscsi_transport_attrs,
116 };
117 
118 static int iscsi_setup_host(struct transport_container *tc, struct device *dev,
119 			    struct class_device *cdev)
120 {
121 	struct Scsi_Host *shost = dev_to_shost(dev);
122 	struct iscsi_host *ihost = shost->shost_data;
123 
124 	memset(ihost, 0, sizeof(*ihost));
125 	INIT_LIST_HEAD(&ihost->sessions);
126 	mutex_init(&ihost->mutex);
127 	return 0;
128 }
129 
130 static DECLARE_TRANSPORT_CLASS(iscsi_host_class,
131 			       "iscsi_host",
132 			       iscsi_setup_host,
133 			       NULL,
134 			       NULL);
135 
136 static DECLARE_TRANSPORT_CLASS(iscsi_session_class,
137 			       "iscsi_session",
138 			       NULL,
139 			       NULL,
140 			       NULL);
141 
142 static DECLARE_TRANSPORT_CLASS(iscsi_connection_class,
143 			       "iscsi_connection",
144 			       NULL,
145 			       NULL,
146 			       NULL);
147 
148 static struct sock *nls;
149 static DEFINE_MUTEX(rx_queue_mutex);
150 
151 static LIST_HEAD(sesslist);
152 static DEFINE_SPINLOCK(sesslock);
153 static LIST_HEAD(connlist);
154 static DEFINE_SPINLOCK(connlock);
155 
156 static uint32_t iscsi_conn_get_sid(struct iscsi_cls_conn *conn)
157 {
158 	struct iscsi_cls_session *sess = iscsi_dev_to_session(conn->dev.parent);
159 	return sess->sid;
160 }
161 
162 /*
163  * Returns the matching session to a given sid
164  */
165 static struct iscsi_cls_session *iscsi_session_lookup(uint32_t sid)
166 {
167 	unsigned long flags;
168 	struct iscsi_cls_session *sess;
169 
170 	spin_lock_irqsave(&sesslock, flags);
171 	list_for_each_entry(sess, &sesslist, sess_list) {
172 		if (sess->sid == sid) {
173 			spin_unlock_irqrestore(&sesslock, flags);
174 			return sess;
175 		}
176 	}
177 	spin_unlock_irqrestore(&sesslock, flags);
178 	return NULL;
179 }
180 
181 /*
182  * Returns the matching connection to a given sid / cid tuple
183  */
184 static struct iscsi_cls_conn *iscsi_conn_lookup(uint32_t sid, uint32_t cid)
185 {
186 	unsigned long flags;
187 	struct iscsi_cls_conn *conn;
188 
189 	spin_lock_irqsave(&connlock, flags);
190 	list_for_each_entry(conn, &connlist, conn_list) {
191 		if ((conn->cid == cid) && (iscsi_conn_get_sid(conn) == sid)) {
192 			spin_unlock_irqrestore(&connlock, flags);
193 			return conn;
194 		}
195 	}
196 	spin_unlock_irqrestore(&connlock, flags);
197 	return NULL;
198 }
199 
200 /*
201  * The following functions can be used by LLDs that allocate
202  * their own scsi_hosts or by software iscsi LLDs
203  */
204 static void iscsi_session_release(struct device *dev)
205 {
206 	struct iscsi_cls_session *session = iscsi_dev_to_session(dev);
207 	struct Scsi_Host *shost;
208 
209 	shost = iscsi_session_to_shost(session);
210 	scsi_host_put(shost);
211 	kfree(session);
212 }
213 
214 static int iscsi_is_session_dev(const struct device *dev)
215 {
216 	return dev->release == iscsi_session_release;
217 }
218 
219 static int iscsi_user_scan(struct Scsi_Host *shost, uint channel,
220 			   uint id, uint lun)
221 {
222 	struct iscsi_host *ihost = shost->shost_data;
223 	struct iscsi_cls_session *session;
224 
225 	mutex_lock(&ihost->mutex);
226 	list_for_each_entry(session, &ihost->sessions, host_list) {
227 		if ((channel == SCAN_WILD_CARD || channel == 0) &&
228 		    (id == SCAN_WILD_CARD || id == session->target_id))
229 			scsi_scan_target(&session->dev, 0,
230 					 session->target_id, lun, 1);
231 	}
232 	mutex_unlock(&ihost->mutex);
233 
234 	return 0;
235 }
236 
237 static void session_recovery_timedout(struct work_struct *work)
238 {
239 	struct iscsi_cls_session *session =
240 		container_of(work, struct iscsi_cls_session,
241 			     recovery_work.work);
242 
243 	dev_printk(KERN_INFO, &session->dev, "iscsi: session recovery timed "
244 		  "out after %d secs\n", session->recovery_tmo);
245 
246 	if (session->transport->session_recovery_timedout)
247 		session->transport->session_recovery_timedout(session);
248 
249 	scsi_target_unblock(&session->dev);
250 }
251 
252 void iscsi_unblock_session(struct iscsi_cls_session *session)
253 {
254 	if (!cancel_delayed_work(&session->recovery_work))
255 		flush_scheduled_work();
256 	scsi_target_unblock(&session->dev);
257 }
258 EXPORT_SYMBOL_GPL(iscsi_unblock_session);
259 
260 void iscsi_block_session(struct iscsi_cls_session *session)
261 {
262 	scsi_target_block(&session->dev);
263 	schedule_delayed_work(&session->recovery_work,
264 			     session->recovery_tmo * HZ);
265 }
266 EXPORT_SYMBOL_GPL(iscsi_block_session);
267 
268 struct iscsi_cls_session *
269 iscsi_alloc_session(struct Scsi_Host *shost,
270 		    struct iscsi_transport *transport)
271 {
272 	struct iscsi_cls_session *session;
273 
274 	session = kzalloc(sizeof(*session) + transport->sessiondata_size,
275 			  GFP_KERNEL);
276 	if (!session)
277 		return NULL;
278 
279 	session->transport = transport;
280 	session->recovery_tmo = 120;
281 	INIT_DELAYED_WORK(&session->recovery_work, session_recovery_timedout);
282 	INIT_LIST_HEAD(&session->host_list);
283 	INIT_LIST_HEAD(&session->sess_list);
284 
285 	/* this is released in the dev's release function */
286 	scsi_host_get(shost);
287 	session->dev.parent = &shost->shost_gendev;
288 	session->dev.release = iscsi_session_release;
289 	device_initialize(&session->dev);
290 	if (transport->sessiondata_size)
291 		session->dd_data = &session[1];
292 	return session;
293 }
294 EXPORT_SYMBOL_GPL(iscsi_alloc_session);
295 
296 int iscsi_add_session(struct iscsi_cls_session *session, unsigned int target_id)
297 {
298 	struct Scsi_Host *shost = iscsi_session_to_shost(session);
299 	struct iscsi_host *ihost;
300 	int err;
301 
302 	ihost = shost->shost_data;
303 	session->sid = iscsi_session_nr++;
304 	session->target_id = target_id;
305 
306 	snprintf(session->dev.bus_id, BUS_ID_SIZE, "session%u",
307 		 session->sid);
308 	err = device_add(&session->dev);
309 	if (err) {
310 		dev_printk(KERN_ERR, &session->dev, "iscsi: could not "
311 			   "register session's dev\n");
312 		goto release_host;
313 	}
314 	transport_register_device(&session->dev);
315 
316 	mutex_lock(&ihost->mutex);
317 	list_add(&session->host_list, &ihost->sessions);
318 	mutex_unlock(&ihost->mutex);
319 	return 0;
320 
321 release_host:
322 	scsi_host_put(shost);
323 	return err;
324 }
325 EXPORT_SYMBOL_GPL(iscsi_add_session);
326 
327 /**
328  * iscsi_create_session - create iscsi class session
329  * @shost: scsi host
330  * @transport: iscsi transport
331  *
332  * This can be called from a LLD or iscsi_transport.
333  **/
334 struct iscsi_cls_session *
335 iscsi_create_session(struct Scsi_Host *shost,
336 		     struct iscsi_transport *transport,
337 		     unsigned int target_id)
338 {
339 	struct iscsi_cls_session *session;
340 
341 	session = iscsi_alloc_session(shost, transport);
342 	if (!session)
343 		return NULL;
344 
345 	if (iscsi_add_session(session, target_id)) {
346 		iscsi_free_session(session);
347 		return NULL;
348 	}
349 	return session;
350 }
351 EXPORT_SYMBOL_GPL(iscsi_create_session);
352 
353 void iscsi_remove_session(struct iscsi_cls_session *session)
354 {
355 	struct Scsi_Host *shost = iscsi_session_to_shost(session);
356 	struct iscsi_host *ihost = shost->shost_data;
357 
358 	if (!cancel_delayed_work(&session->recovery_work))
359 		flush_scheduled_work();
360 
361 	mutex_lock(&ihost->mutex);
362 	list_del(&session->host_list);
363 	mutex_unlock(&ihost->mutex);
364 
365 	scsi_remove_target(&session->dev);
366 
367 	transport_unregister_device(&session->dev);
368 	device_del(&session->dev);
369 }
370 EXPORT_SYMBOL_GPL(iscsi_remove_session);
371 
372 void iscsi_free_session(struct iscsi_cls_session *session)
373 {
374 	put_device(&session->dev);
375 }
376 
377 EXPORT_SYMBOL_GPL(iscsi_free_session);
378 
379 /**
380  * iscsi_destroy_session - destroy iscsi session
381  * @session: iscsi_session
382  *
383  * Can be called by a LLD or iscsi_transport. There must not be
384  * any running connections.
385  **/
386 int iscsi_destroy_session(struct iscsi_cls_session *session)
387 {
388 	iscsi_remove_session(session);
389 	iscsi_free_session(session);
390 	return 0;
391 }
392 EXPORT_SYMBOL_GPL(iscsi_destroy_session);
393 
394 static void iscsi_conn_release(struct device *dev)
395 {
396 	struct iscsi_cls_conn *conn = iscsi_dev_to_conn(dev);
397 	struct device *parent = conn->dev.parent;
398 
399 	kfree(conn);
400 	put_device(parent);
401 }
402 
403 static int iscsi_is_conn_dev(const struct device *dev)
404 {
405 	return dev->release == iscsi_conn_release;
406 }
407 
408 /**
409  * iscsi_create_conn - create iscsi class connection
410  * @session: iscsi cls session
411  * @cid: connection id
412  *
413  * This can be called from a LLD or iscsi_transport. The connection
414  * is child of the session so cid must be unique for all connections
415  * on the session.
416  *
417  * Since we do not support MCS, cid will normally be zero. In some cases
418  * for software iscsi we could be trying to preallocate a connection struct
419  * in which case there could be two connection structs and cid would be
420  * non-zero.
421  **/
422 struct iscsi_cls_conn *
423 iscsi_create_conn(struct iscsi_cls_session *session, uint32_t cid)
424 {
425 	struct iscsi_transport *transport = session->transport;
426 	struct iscsi_cls_conn *conn;
427 	int err;
428 
429 	conn = kzalloc(sizeof(*conn) + transport->conndata_size, GFP_KERNEL);
430 	if (!conn)
431 		return NULL;
432 
433 	if (transport->conndata_size)
434 		conn->dd_data = &conn[1];
435 
436 	INIT_LIST_HEAD(&conn->conn_list);
437 	conn->transport = transport;
438 	conn->cid = cid;
439 
440 	/* this is released in the dev's release function */
441 	if (!get_device(&session->dev))
442 		goto free_conn;
443 
444 	snprintf(conn->dev.bus_id, BUS_ID_SIZE, "connection%d:%u",
445 		 session->sid, cid);
446 	conn->dev.parent = &session->dev;
447 	conn->dev.release = iscsi_conn_release;
448 	err = device_register(&conn->dev);
449 	if (err) {
450 		dev_printk(KERN_ERR, &conn->dev, "iscsi: could not register "
451 			   "connection's dev\n");
452 		goto release_parent_ref;
453 	}
454 	transport_register_device(&conn->dev);
455 	return conn;
456 
457 release_parent_ref:
458 	put_device(&session->dev);
459 free_conn:
460 	kfree(conn);
461 	return NULL;
462 }
463 
464 EXPORT_SYMBOL_GPL(iscsi_create_conn);
465 
466 /**
467  * iscsi_destroy_conn - destroy iscsi class connection
468  * @session: iscsi cls session
469  *
470  * This can be called from a LLD or iscsi_transport.
471  **/
472 int iscsi_destroy_conn(struct iscsi_cls_conn *conn)
473 {
474 	transport_unregister_device(&conn->dev);
475 	device_unregister(&conn->dev);
476 	return 0;
477 }
478 
479 EXPORT_SYMBOL_GPL(iscsi_destroy_conn);
480 
481 /*
482  * iscsi interface functions
483  */
484 static struct iscsi_internal *
485 iscsi_if_transport_lookup(struct iscsi_transport *tt)
486 {
487 	struct iscsi_internal *priv;
488 	unsigned long flags;
489 
490 	spin_lock_irqsave(&iscsi_transport_lock, flags);
491 	list_for_each_entry(priv, &iscsi_transports, list) {
492 		if (tt == priv->iscsi_transport) {
493 			spin_unlock_irqrestore(&iscsi_transport_lock, flags);
494 			return priv;
495 		}
496 	}
497 	spin_unlock_irqrestore(&iscsi_transport_lock, flags);
498 	return NULL;
499 }
500 
501 static int
502 iscsi_broadcast_skb(struct sk_buff *skb, gfp_t gfp)
503 {
504 	int rc;
505 
506 	rc = netlink_broadcast(nls, skb, 0, 1, gfp);
507 	if (rc < 0) {
508 		printk(KERN_ERR "iscsi: can not broadcast skb (%d)\n", rc);
509 		return rc;
510 	}
511 
512 	return 0;
513 }
514 
515 static int
516 iscsi_unicast_skb(struct sk_buff *skb, int pid)
517 {
518 	int rc;
519 
520 	rc = netlink_unicast(nls, skb, pid, MSG_DONTWAIT);
521 	if (rc < 0) {
522 		printk(KERN_ERR "iscsi: can not unicast skb (%d)\n", rc);
523 		return rc;
524 	}
525 
526 	return 0;
527 }
528 
529 int iscsi_recv_pdu(struct iscsi_cls_conn *conn, struct iscsi_hdr *hdr,
530 		   char *data, uint32_t data_size)
531 {
532 	struct nlmsghdr	*nlh;
533 	struct sk_buff *skb;
534 	struct iscsi_uevent *ev;
535 	char *pdu;
536 	struct iscsi_internal *priv;
537 	int len = NLMSG_SPACE(sizeof(*ev) + sizeof(struct iscsi_hdr) +
538 			      data_size);
539 
540 	priv = iscsi_if_transport_lookup(conn->transport);
541 	if (!priv)
542 		return -EINVAL;
543 
544 	skb = alloc_skb(len, GFP_ATOMIC);
545 	if (!skb) {
546 		iscsi_conn_error(conn, ISCSI_ERR_CONN_FAILED);
547 		dev_printk(KERN_ERR, &conn->dev, "iscsi: can not deliver "
548 			   "control PDU: OOM\n");
549 		return -ENOMEM;
550 	}
551 
552 	nlh = __nlmsg_put(skb, priv->daemon_pid, 0, 0, (len - sizeof(*nlh)), 0);
553 	ev = NLMSG_DATA(nlh);
554 	memset(ev, 0, sizeof(*ev));
555 	ev->transport_handle = iscsi_handle(conn->transport);
556 	ev->type = ISCSI_KEVENT_RECV_PDU;
557 	ev->r.recv_req.cid = conn->cid;
558 	ev->r.recv_req.sid = iscsi_conn_get_sid(conn);
559 	pdu = (char*)ev + sizeof(*ev);
560 	memcpy(pdu, hdr, sizeof(struct iscsi_hdr));
561 	memcpy(pdu + sizeof(struct iscsi_hdr), data, data_size);
562 
563 	return iscsi_unicast_skb(skb, priv->daemon_pid);
564 }
565 EXPORT_SYMBOL_GPL(iscsi_recv_pdu);
566 
567 void iscsi_conn_error(struct iscsi_cls_conn *conn, enum iscsi_err error)
568 {
569 	struct nlmsghdr	*nlh;
570 	struct sk_buff	*skb;
571 	struct iscsi_uevent *ev;
572 	struct iscsi_internal *priv;
573 	int len = NLMSG_SPACE(sizeof(*ev));
574 
575 	priv = iscsi_if_transport_lookup(conn->transport);
576 	if (!priv)
577 		return;
578 
579 	skb = alloc_skb(len, GFP_ATOMIC);
580 	if (!skb) {
581 		dev_printk(KERN_ERR, &conn->dev, "iscsi: gracefully ignored "
582 			  "conn error (%d)\n", error);
583 		return;
584 	}
585 
586 	nlh = __nlmsg_put(skb, priv->daemon_pid, 0, 0, (len - sizeof(*nlh)), 0);
587 	ev = NLMSG_DATA(nlh);
588 	ev->transport_handle = iscsi_handle(conn->transport);
589 	ev->type = ISCSI_KEVENT_CONN_ERROR;
590 	ev->r.connerror.error = error;
591 	ev->r.connerror.cid = conn->cid;
592 	ev->r.connerror.sid = iscsi_conn_get_sid(conn);
593 
594 	iscsi_broadcast_skb(skb, GFP_ATOMIC);
595 
596 	dev_printk(KERN_INFO, &conn->dev, "iscsi: detected conn error (%d)\n",
597 		   error);
598 }
599 EXPORT_SYMBOL_GPL(iscsi_conn_error);
600 
601 static int
602 iscsi_if_send_reply(int pid, int seq, int type, int done, int multi,
603 		      void *payload, int size)
604 {
605 	struct sk_buff	*skb;
606 	struct nlmsghdr	*nlh;
607 	int len = NLMSG_SPACE(size);
608 	int flags = multi ? NLM_F_MULTI : 0;
609 	int t = done ? NLMSG_DONE : type;
610 
611 	skb = alloc_skb(len, GFP_ATOMIC);
612 	/*
613 	 * FIXME:
614 	 * user is supposed to react on iferror == -ENOMEM;
615 	 * see iscsi_if_rx().
616 	 */
617 	BUG_ON(!skb);
618 
619 	nlh = __nlmsg_put(skb, pid, seq, t, (len - sizeof(*nlh)), 0);
620 	nlh->nlmsg_flags = flags;
621 	memcpy(NLMSG_DATA(nlh), payload, size);
622 	return iscsi_unicast_skb(skb, pid);
623 }
624 
625 static int
626 iscsi_if_get_stats(struct iscsi_transport *transport, struct nlmsghdr *nlh)
627 {
628 	struct iscsi_uevent *ev = NLMSG_DATA(nlh);
629 	struct iscsi_stats *stats;
630 	struct sk_buff *skbstat;
631 	struct iscsi_cls_conn *conn;
632 	struct nlmsghdr	*nlhstat;
633 	struct iscsi_uevent *evstat;
634 	struct iscsi_internal *priv;
635 	int len = NLMSG_SPACE(sizeof(*ev) +
636 			      sizeof(struct iscsi_stats) +
637 			      sizeof(struct iscsi_stats_custom) *
638 			      ISCSI_STATS_CUSTOM_MAX);
639 	int err = 0;
640 
641 	priv = iscsi_if_transport_lookup(transport);
642 	if (!priv)
643 		return -EINVAL;
644 
645 	conn = iscsi_conn_lookup(ev->u.get_stats.sid, ev->u.get_stats.cid);
646 	if (!conn)
647 		return -EEXIST;
648 
649 	do {
650 		int actual_size;
651 
652 		skbstat = alloc_skb(len, GFP_ATOMIC);
653 		if (!skbstat) {
654 			dev_printk(KERN_ERR, &conn->dev, "iscsi: can not "
655 				   "deliver stats: OOM\n");
656 			return -ENOMEM;
657 		}
658 
659 		nlhstat = __nlmsg_put(skbstat, priv->daemon_pid, 0, 0,
660 				      (len - sizeof(*nlhstat)), 0);
661 		evstat = NLMSG_DATA(nlhstat);
662 		memset(evstat, 0, sizeof(*evstat));
663 		evstat->transport_handle = iscsi_handle(conn->transport);
664 		evstat->type = nlh->nlmsg_type;
665 		evstat->u.get_stats.cid =
666 			ev->u.get_stats.cid;
667 		evstat->u.get_stats.sid =
668 			ev->u.get_stats.sid;
669 		stats = (struct iscsi_stats *)
670 			((char*)evstat + sizeof(*evstat));
671 		memset(stats, 0, sizeof(*stats));
672 
673 		transport->get_stats(conn, stats);
674 		actual_size = NLMSG_SPACE(sizeof(struct iscsi_uevent) +
675 					  sizeof(struct iscsi_stats) +
676 					  sizeof(struct iscsi_stats_custom) *
677 					  stats->custom_length);
678 		actual_size -= sizeof(*nlhstat);
679 		actual_size = NLMSG_LENGTH(actual_size);
680 		skb_trim(skbstat, NLMSG_ALIGN(actual_size));
681 		nlhstat->nlmsg_len = actual_size;
682 
683 		err = iscsi_unicast_skb(skbstat, priv->daemon_pid);
684 	} while (err < 0 && err != -ECONNREFUSED);
685 
686 	return err;
687 }
688 
689 /**
690  * iscsi_if_destroy_session_done - send session destr. completion event
691  * @conn: last connection for session
692  *
693  * This is called by HW iscsi LLDs to notify userpsace that its HW has
694  * removed a session.
695  **/
696 int iscsi_if_destroy_session_done(struct iscsi_cls_conn *conn)
697 {
698 	struct iscsi_internal *priv;
699 	struct iscsi_cls_session *session;
700 	struct Scsi_Host *shost;
701 	struct iscsi_uevent *ev;
702 	struct sk_buff  *skb;
703 	struct nlmsghdr *nlh;
704 	unsigned long flags;
705 	int rc, len = NLMSG_SPACE(sizeof(*ev));
706 
707 	priv = iscsi_if_transport_lookup(conn->transport);
708 	if (!priv)
709 		return -EINVAL;
710 
711 	session = iscsi_dev_to_session(conn->dev.parent);
712 	shost = iscsi_session_to_shost(session);
713 
714 	skb = alloc_skb(len, GFP_KERNEL);
715 	if (!skb) {
716 		dev_printk(KERN_ERR, &conn->dev, "Cannot notify userspace of "
717 			  "session creation event\n");
718 		return -ENOMEM;
719 	}
720 
721 	nlh = __nlmsg_put(skb, priv->daemon_pid, 0, 0, (len - sizeof(*nlh)), 0);
722 	ev = NLMSG_DATA(nlh);
723 	ev->transport_handle = iscsi_handle(conn->transport);
724 	ev->type = ISCSI_KEVENT_DESTROY_SESSION;
725 	ev->r.d_session.host_no = shost->host_no;
726 	ev->r.d_session.sid = session->sid;
727 
728 	/*
729 	 * this will occur if the daemon is not up, so we just warn
730 	 * the user and when the daemon is restarted it will handle it
731 	 */
732 	rc = iscsi_broadcast_skb(skb, GFP_KERNEL);
733 	if (rc < 0)
734 		dev_printk(KERN_ERR, &conn->dev, "Cannot notify userspace of "
735 			  "session destruction event. Check iscsi daemon\n");
736 
737 	spin_lock_irqsave(&sesslock, flags);
738 	list_del(&session->sess_list);
739 	spin_unlock_irqrestore(&sesslock, flags);
740 
741 	spin_lock_irqsave(&connlock, flags);
742 	conn->active = 0;
743 	list_del(&conn->conn_list);
744 	spin_unlock_irqrestore(&connlock, flags);
745 
746 	return rc;
747 }
748 EXPORT_SYMBOL_GPL(iscsi_if_destroy_session_done);
749 
750 /**
751  * iscsi_if_create_session_done - send session creation completion event
752  * @conn: leading connection for session
753  *
754  * This is called by HW iscsi LLDs to notify userpsace that its HW has
755  * created a session or a existing session is back in the logged in state.
756  **/
757 int iscsi_if_create_session_done(struct iscsi_cls_conn *conn)
758 {
759 	struct iscsi_internal *priv;
760 	struct iscsi_cls_session *session;
761 	struct Scsi_Host *shost;
762 	struct iscsi_uevent *ev;
763 	struct sk_buff  *skb;
764 	struct nlmsghdr *nlh;
765 	unsigned long flags;
766 	int rc, len = NLMSG_SPACE(sizeof(*ev));
767 
768 	priv = iscsi_if_transport_lookup(conn->transport);
769 	if (!priv)
770 		return -EINVAL;
771 
772 	session = iscsi_dev_to_session(conn->dev.parent);
773 	shost = iscsi_session_to_shost(session);
774 
775 	skb = alloc_skb(len, GFP_KERNEL);
776 	if (!skb) {
777 		dev_printk(KERN_ERR, &conn->dev, "Cannot notify userspace of "
778 			  "session creation event\n");
779 		return -ENOMEM;
780 	}
781 
782 	nlh = __nlmsg_put(skb, priv->daemon_pid, 0, 0, (len - sizeof(*nlh)), 0);
783 	ev = NLMSG_DATA(nlh);
784 	ev->transport_handle = iscsi_handle(conn->transport);
785 	ev->type = ISCSI_UEVENT_CREATE_SESSION;
786 	ev->r.c_session_ret.host_no = shost->host_no;
787 	ev->r.c_session_ret.sid = session->sid;
788 
789 	/*
790 	 * this will occur if the daemon is not up, so we just warn
791 	 * the user and when the daemon is restarted it will handle it
792 	 */
793 	rc = iscsi_broadcast_skb(skb, GFP_KERNEL);
794 	if (rc < 0)
795 		dev_printk(KERN_ERR, &conn->dev, "Cannot notify userspace of "
796 			  "session creation event. Check iscsi daemon\n");
797 
798 	spin_lock_irqsave(&sesslock, flags);
799 	list_add(&session->sess_list, &sesslist);
800 	spin_unlock_irqrestore(&sesslock, flags);
801 
802 	spin_lock_irqsave(&connlock, flags);
803 	list_add(&conn->conn_list, &connlist);
804 	conn->active = 1;
805 	spin_unlock_irqrestore(&connlock, flags);
806 	return rc;
807 }
808 EXPORT_SYMBOL_GPL(iscsi_if_create_session_done);
809 
810 static int
811 iscsi_if_create_session(struct iscsi_internal *priv, struct iscsi_uevent *ev)
812 {
813 	struct iscsi_transport *transport = priv->iscsi_transport;
814 	struct iscsi_cls_session *session;
815 	unsigned long flags;
816 	uint32_t hostno;
817 
818 	session = transport->create_session(transport, &priv->t,
819 					    ev->u.c_session.initial_cmdsn,
820 					    &hostno);
821 	if (!session)
822 		return -ENOMEM;
823 
824 	spin_lock_irqsave(&sesslock, flags);
825 	list_add(&session->sess_list, &sesslist);
826 	spin_unlock_irqrestore(&sesslock, flags);
827 
828 	ev->r.c_session_ret.host_no = hostno;
829 	ev->r.c_session_ret.sid = session->sid;
830 	return 0;
831 }
832 
833 static int
834 iscsi_if_create_conn(struct iscsi_transport *transport, struct iscsi_uevent *ev)
835 {
836 	struct iscsi_cls_conn *conn;
837 	struct iscsi_cls_session *session;
838 	unsigned long flags;
839 
840 	session = iscsi_session_lookup(ev->u.c_conn.sid);
841 	if (!session) {
842 		printk(KERN_ERR "iscsi: invalid session %d\n",
843 		       ev->u.c_conn.sid);
844 		return -EINVAL;
845 	}
846 
847 	conn = transport->create_conn(session, ev->u.c_conn.cid);
848 	if (!conn) {
849 		printk(KERN_ERR "iscsi: couldn't create a new "
850 			   "connection for session %d\n",
851 			   session->sid);
852 		return -ENOMEM;
853 	}
854 
855 	ev->r.c_conn_ret.sid = session->sid;
856 	ev->r.c_conn_ret.cid = conn->cid;
857 
858 	spin_lock_irqsave(&connlock, flags);
859 	list_add(&conn->conn_list, &connlist);
860 	conn->active = 1;
861 	spin_unlock_irqrestore(&connlock, flags);
862 
863 	return 0;
864 }
865 
866 static int
867 iscsi_if_destroy_conn(struct iscsi_transport *transport, struct iscsi_uevent *ev)
868 {
869 	unsigned long flags;
870 	struct iscsi_cls_conn *conn;
871 
872 	conn = iscsi_conn_lookup(ev->u.d_conn.sid, ev->u.d_conn.cid);
873 	if (!conn)
874 		return -EINVAL;
875 	spin_lock_irqsave(&connlock, flags);
876 	conn->active = 0;
877 	list_del(&conn->conn_list);
878 	spin_unlock_irqrestore(&connlock, flags);
879 
880 	if (transport->destroy_conn)
881 		transport->destroy_conn(conn);
882 	return 0;
883 }
884 
885 static int
886 iscsi_set_param(struct iscsi_transport *transport, struct iscsi_uevent *ev)
887 {
888 	char *data = (char*)ev + sizeof(*ev);
889 	struct iscsi_cls_conn *conn;
890 	struct iscsi_cls_session *session;
891 	int err = 0, value = 0;
892 
893 	session = iscsi_session_lookup(ev->u.set_param.sid);
894 	conn = iscsi_conn_lookup(ev->u.set_param.sid, ev->u.set_param.cid);
895 	if (!conn || !session)
896 		return -EINVAL;
897 
898 	switch (ev->u.set_param.param) {
899 	case ISCSI_PARAM_SESS_RECOVERY_TMO:
900 		sscanf(data, "%d", &value);
901 		if (value != 0)
902 			session->recovery_tmo = value;
903 		break;
904 	default:
905 		err = transport->set_param(conn, ev->u.set_param.param,
906 					   data, ev->u.set_param.len);
907 	}
908 
909 	return err;
910 }
911 
912 static int
913 iscsi_if_transport_ep(struct iscsi_transport *transport,
914 		      struct iscsi_uevent *ev, int msg_type)
915 {
916 	struct sockaddr *dst_addr;
917 	int rc = 0;
918 
919 	switch (msg_type) {
920 	case ISCSI_UEVENT_TRANSPORT_EP_CONNECT:
921 		if (!transport->ep_connect)
922 			return -EINVAL;
923 
924 		dst_addr = (struct sockaddr *)((char*)ev + sizeof(*ev));
925 		rc = transport->ep_connect(dst_addr,
926 					   ev->u.ep_connect.non_blocking,
927 					   &ev->r.ep_connect_ret.handle);
928 		break;
929 	case ISCSI_UEVENT_TRANSPORT_EP_POLL:
930 		if (!transport->ep_poll)
931 			return -EINVAL;
932 
933 		ev->r.retcode = transport->ep_poll(ev->u.ep_poll.ep_handle,
934 						   ev->u.ep_poll.timeout_ms);
935 		break;
936 	case ISCSI_UEVENT_TRANSPORT_EP_DISCONNECT:
937 		if (!transport->ep_disconnect)
938 			return -EINVAL;
939 
940 		transport->ep_disconnect(ev->u.ep_disconnect.ep_handle);
941 		break;
942 	}
943 	return rc;
944 }
945 
946 static int
947 iscsi_tgt_dscvr(struct iscsi_transport *transport,
948 		struct iscsi_uevent *ev)
949 {
950 	struct sockaddr *dst_addr;
951 
952 	if (!transport->tgt_dscvr)
953 		return -EINVAL;
954 
955 	dst_addr = (struct sockaddr *)((char*)ev + sizeof(*ev));
956 	return transport->tgt_dscvr(ev->u.tgt_dscvr.type,
957 				    ev->u.tgt_dscvr.host_no,
958 				    ev->u.tgt_dscvr.enable, dst_addr);
959 }
960 
961 static int
962 iscsi_if_recv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
963 {
964 	int err = 0;
965 	struct iscsi_uevent *ev = NLMSG_DATA(nlh);
966 	struct iscsi_transport *transport = NULL;
967 	struct iscsi_internal *priv;
968 	struct iscsi_cls_session *session;
969 	struct iscsi_cls_conn *conn;
970 	unsigned long flags;
971 
972 	priv = iscsi_if_transport_lookup(iscsi_ptr(ev->transport_handle));
973 	if (!priv)
974 		return -EINVAL;
975 	transport = priv->iscsi_transport;
976 
977 	if (!try_module_get(transport->owner))
978 		return -EINVAL;
979 
980 	priv->daemon_pid = NETLINK_CREDS(skb)->pid;
981 
982 	switch (nlh->nlmsg_type) {
983 	case ISCSI_UEVENT_CREATE_SESSION:
984 		err = iscsi_if_create_session(priv, ev);
985 		break;
986 	case ISCSI_UEVENT_DESTROY_SESSION:
987 		session = iscsi_session_lookup(ev->u.d_session.sid);
988 		if (session) {
989 			spin_lock_irqsave(&sesslock, flags);
990 			list_del(&session->sess_list);
991 			spin_unlock_irqrestore(&sesslock, flags);
992 
993 			transport->destroy_session(session);
994 		} else
995 			err = -EINVAL;
996 		break;
997 	case ISCSI_UEVENT_CREATE_CONN:
998 		err = iscsi_if_create_conn(transport, ev);
999 		break;
1000 	case ISCSI_UEVENT_DESTROY_CONN:
1001 		err = iscsi_if_destroy_conn(transport, ev);
1002 		break;
1003 	case ISCSI_UEVENT_BIND_CONN:
1004 		session = iscsi_session_lookup(ev->u.b_conn.sid);
1005 		conn = iscsi_conn_lookup(ev->u.b_conn.sid, ev->u.b_conn.cid);
1006 
1007 		if (session && conn)
1008 			ev->r.retcode =	transport->bind_conn(session, conn,
1009 					ev->u.b_conn.transport_eph,
1010 					ev->u.b_conn.is_leading);
1011 		else
1012 			err = -EINVAL;
1013 		break;
1014 	case ISCSI_UEVENT_SET_PARAM:
1015 		err = iscsi_set_param(transport, ev);
1016 		break;
1017 	case ISCSI_UEVENT_START_CONN:
1018 		conn = iscsi_conn_lookup(ev->u.start_conn.sid, ev->u.start_conn.cid);
1019 		if (conn)
1020 			ev->r.retcode = transport->start_conn(conn);
1021 		else
1022 			err = -EINVAL;
1023 		break;
1024 	case ISCSI_UEVENT_STOP_CONN:
1025 		conn = iscsi_conn_lookup(ev->u.stop_conn.sid, ev->u.stop_conn.cid);
1026 		if (conn)
1027 			transport->stop_conn(conn, ev->u.stop_conn.flag);
1028 		else
1029 			err = -EINVAL;
1030 		break;
1031 	case ISCSI_UEVENT_SEND_PDU:
1032 		conn = iscsi_conn_lookup(ev->u.send_pdu.sid, ev->u.send_pdu.cid);
1033 		if (conn)
1034 			ev->r.retcode =	transport->send_pdu(conn,
1035 				(struct iscsi_hdr*)((char*)ev + sizeof(*ev)),
1036 				(char*)ev + sizeof(*ev) + ev->u.send_pdu.hdr_size,
1037 				ev->u.send_pdu.data_size);
1038 		else
1039 			err = -EINVAL;
1040 		break;
1041 	case ISCSI_UEVENT_GET_STATS:
1042 		err = iscsi_if_get_stats(transport, nlh);
1043 		break;
1044 	case ISCSI_UEVENT_TRANSPORT_EP_CONNECT:
1045 	case ISCSI_UEVENT_TRANSPORT_EP_POLL:
1046 	case ISCSI_UEVENT_TRANSPORT_EP_DISCONNECT:
1047 		err = iscsi_if_transport_ep(transport, ev, nlh->nlmsg_type);
1048 		break;
1049 	case ISCSI_UEVENT_TGT_DSCVR:
1050 		err = iscsi_tgt_dscvr(transport, ev);
1051 		break;
1052 	default:
1053 		err = -EINVAL;
1054 		break;
1055 	}
1056 
1057 	module_put(transport->owner);
1058 	return err;
1059 }
1060 
1061 /*
1062  * Get message from skb (based on rtnetlink_rcv_skb).  Each message is
1063  * processed by iscsi_if_recv_msg.  Malformed skbs with wrong lengths or
1064  * invalid creds are discarded silently.
1065  */
1066 static void
1067 iscsi_if_rx(struct sock *sk, int len)
1068 {
1069 	struct sk_buff *skb;
1070 
1071 	mutex_lock(&rx_queue_mutex);
1072 	while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1073 		if (NETLINK_CREDS(skb)->uid) {
1074 			skb_pull(skb, skb->len);
1075 			goto free_skb;
1076 		}
1077 
1078 		while (skb->len >= NLMSG_SPACE(0)) {
1079 			int err;
1080 			uint32_t rlen;
1081 			struct nlmsghdr	*nlh;
1082 			struct iscsi_uevent *ev;
1083 
1084 			nlh = (struct nlmsghdr *)skb->data;
1085 			if (nlh->nlmsg_len < sizeof(*nlh) ||
1086 			    skb->len < nlh->nlmsg_len) {
1087 				break;
1088 			}
1089 
1090 			ev = NLMSG_DATA(nlh);
1091 			rlen = NLMSG_ALIGN(nlh->nlmsg_len);
1092 			if (rlen > skb->len)
1093 				rlen = skb->len;
1094 
1095 			err = iscsi_if_recv_msg(skb, nlh);
1096 			if (err) {
1097 				ev->type = ISCSI_KEVENT_IF_ERROR;
1098 				ev->iferror = err;
1099 			}
1100 			do {
1101 				/*
1102 				 * special case for GET_STATS:
1103 				 * on success - sending reply and stats from
1104 				 * inside of if_recv_msg(),
1105 				 * on error - fall through.
1106 				 */
1107 				if (ev->type == ISCSI_UEVENT_GET_STATS && !err)
1108 					break;
1109 				err = iscsi_if_send_reply(
1110 					NETLINK_CREDS(skb)->pid, nlh->nlmsg_seq,
1111 					nlh->nlmsg_type, 0, 0, ev, sizeof(*ev));
1112 			} while (err < 0 && err != -ECONNREFUSED);
1113 			skb_pull(skb, rlen);
1114 		}
1115 free_skb:
1116 		kfree_skb(skb);
1117 	}
1118 	mutex_unlock(&rx_queue_mutex);
1119 }
1120 
1121 #define iscsi_cdev_to_conn(_cdev) \
1122 	iscsi_dev_to_conn(_cdev->dev)
1123 
1124 #define ISCSI_CLASS_ATTR(_prefix,_name,_mode,_show,_store)		\
1125 struct class_device_attribute class_device_attr_##_prefix##_##_name =	\
1126 	__ATTR(_name,_mode,_show,_store)
1127 
1128 /*
1129  * iSCSI connection attrs
1130  */
1131 #define iscsi_conn_attr_show(param)					\
1132 static ssize_t								\
1133 show_conn_param_##param(struct class_device *cdev, char *buf)		\
1134 {									\
1135 	struct iscsi_cls_conn *conn = iscsi_cdev_to_conn(cdev);		\
1136 	struct iscsi_transport *t = conn->transport;			\
1137 	return t->get_conn_param(conn, param, buf);			\
1138 }
1139 
1140 #define iscsi_conn_attr(field, param)					\
1141 	iscsi_conn_attr_show(param)					\
1142 static ISCSI_CLASS_ATTR(conn, field, S_IRUGO, show_conn_param_##param,	\
1143 			NULL);
1144 
1145 iscsi_conn_attr(max_recv_dlength, ISCSI_PARAM_MAX_RECV_DLENGTH);
1146 iscsi_conn_attr(max_xmit_dlength, ISCSI_PARAM_MAX_XMIT_DLENGTH);
1147 iscsi_conn_attr(header_digest, ISCSI_PARAM_HDRDGST_EN);
1148 iscsi_conn_attr(data_digest, ISCSI_PARAM_DATADGST_EN);
1149 iscsi_conn_attr(ifmarker, ISCSI_PARAM_IFMARKER_EN);
1150 iscsi_conn_attr(ofmarker, ISCSI_PARAM_OFMARKER_EN);
1151 iscsi_conn_attr(persistent_port, ISCSI_PARAM_PERSISTENT_PORT);
1152 iscsi_conn_attr(port, ISCSI_PARAM_CONN_PORT);
1153 iscsi_conn_attr(exp_statsn, ISCSI_PARAM_EXP_STATSN);
1154 iscsi_conn_attr(persistent_address, ISCSI_PARAM_PERSISTENT_ADDRESS);
1155 iscsi_conn_attr(address, ISCSI_PARAM_CONN_ADDRESS);
1156 
1157 #define iscsi_cdev_to_session(_cdev) \
1158 	iscsi_dev_to_session(_cdev->dev)
1159 
1160 /*
1161  * iSCSI session attrs
1162  */
1163 #define iscsi_session_attr_show(param)					\
1164 static ssize_t								\
1165 show_session_param_##param(struct class_device *cdev, char *buf)	\
1166 {									\
1167 	struct iscsi_cls_session *session = iscsi_cdev_to_session(cdev); \
1168 	struct iscsi_transport *t = session->transport;			\
1169 	return t->get_session_param(session, param, buf);		\
1170 }
1171 
1172 #define iscsi_session_attr(field, param)				\
1173 	iscsi_session_attr_show(param)					\
1174 static ISCSI_CLASS_ATTR(sess, field, S_IRUGO, show_session_param_##param, \
1175 			NULL);
1176 
1177 iscsi_session_attr(targetname, ISCSI_PARAM_TARGET_NAME);
1178 iscsi_session_attr(initial_r2t, ISCSI_PARAM_INITIAL_R2T_EN);
1179 iscsi_session_attr(max_outstanding_r2t, ISCSI_PARAM_MAX_R2T);
1180 iscsi_session_attr(immediate_data, ISCSI_PARAM_IMM_DATA_EN);
1181 iscsi_session_attr(first_burst_len, ISCSI_PARAM_FIRST_BURST);
1182 iscsi_session_attr(max_burst_len, ISCSI_PARAM_MAX_BURST);
1183 iscsi_session_attr(data_pdu_in_order, ISCSI_PARAM_PDU_INORDER_EN);
1184 iscsi_session_attr(data_seq_in_order, ISCSI_PARAM_DATASEQ_INORDER_EN);
1185 iscsi_session_attr(erl, ISCSI_PARAM_ERL);
1186 iscsi_session_attr(tpgt, ISCSI_PARAM_TPGT);
1187 
1188 #define iscsi_priv_session_attr_show(field, format)			\
1189 static ssize_t								\
1190 show_priv_session_##field(struct class_device *cdev, char *buf)		\
1191 {									\
1192 	struct iscsi_cls_session *session = iscsi_cdev_to_session(cdev);\
1193 	return sprintf(buf, format"\n", session->field);		\
1194 }
1195 
1196 #define iscsi_priv_session_attr(field, format)				\
1197 	iscsi_priv_session_attr_show(field, format)			\
1198 static ISCSI_CLASS_ATTR(priv_sess, field, S_IRUGO, show_priv_session_##field, \
1199 			NULL)
1200 iscsi_priv_session_attr(recovery_tmo, "%d");
1201 
1202 #define SETUP_PRIV_SESSION_RD_ATTR(field)				\
1203 do {									\
1204 	priv->session_attrs[count] = &class_device_attr_priv_sess_##field; \
1205 	count++;							\
1206 } while (0)
1207 
1208 
1209 #define SETUP_SESSION_RD_ATTR(field, param_flag)			\
1210 do {									\
1211 	if (tt->param_mask & param_flag) {				\
1212 		priv->session_attrs[count] = &class_device_attr_sess_##field; \
1213 		count++;						\
1214 	}								\
1215 } while (0)
1216 
1217 #define SETUP_CONN_RD_ATTR(field, param_flag)				\
1218 do {									\
1219 	if (tt->param_mask & param_flag) {				\
1220 		priv->conn_attrs[count] = &class_device_attr_conn_##field; \
1221 		count++;						\
1222 	}								\
1223 } while (0)
1224 
1225 static int iscsi_session_match(struct attribute_container *cont,
1226 			   struct device *dev)
1227 {
1228 	struct iscsi_cls_session *session;
1229 	struct Scsi_Host *shost;
1230 	struct iscsi_internal *priv;
1231 
1232 	if (!iscsi_is_session_dev(dev))
1233 		return 0;
1234 
1235 	session = iscsi_dev_to_session(dev);
1236 	shost = iscsi_session_to_shost(session);
1237 	if (!shost->transportt)
1238 		return 0;
1239 
1240 	priv = to_iscsi_internal(shost->transportt);
1241 	if (priv->session_cont.ac.class != &iscsi_session_class.class)
1242 		return 0;
1243 
1244 	return &priv->session_cont.ac == cont;
1245 }
1246 
1247 static int iscsi_conn_match(struct attribute_container *cont,
1248 			   struct device *dev)
1249 {
1250 	struct iscsi_cls_session *session;
1251 	struct iscsi_cls_conn *conn;
1252 	struct Scsi_Host *shost;
1253 	struct iscsi_internal *priv;
1254 
1255 	if (!iscsi_is_conn_dev(dev))
1256 		return 0;
1257 
1258 	conn = iscsi_dev_to_conn(dev);
1259 	session = iscsi_dev_to_session(conn->dev.parent);
1260 	shost = iscsi_session_to_shost(session);
1261 
1262 	if (!shost->transportt)
1263 		return 0;
1264 
1265 	priv = to_iscsi_internal(shost->transportt);
1266 	if (priv->conn_cont.ac.class != &iscsi_connection_class.class)
1267 		return 0;
1268 
1269 	return &priv->conn_cont.ac == cont;
1270 }
1271 
1272 static int iscsi_host_match(struct attribute_container *cont,
1273 			    struct device *dev)
1274 {
1275 	struct Scsi_Host *shost;
1276 	struct iscsi_internal *priv;
1277 
1278 	if (!scsi_is_host_device(dev))
1279 		return 0;
1280 
1281 	shost = dev_to_shost(dev);
1282 	if (!shost->transportt  ||
1283 	    shost->transportt->host_attrs.ac.class != &iscsi_host_class.class)
1284 		return 0;
1285 
1286         priv = to_iscsi_internal(shost->transportt);
1287         return &priv->t.host_attrs.ac == cont;
1288 }
1289 
1290 struct scsi_transport_template *
1291 iscsi_register_transport(struct iscsi_transport *tt)
1292 {
1293 	struct iscsi_internal *priv;
1294 	unsigned long flags;
1295 	int count = 0, err;
1296 
1297 	BUG_ON(!tt);
1298 
1299 	priv = iscsi_if_transport_lookup(tt);
1300 	if (priv)
1301 		return NULL;
1302 
1303 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
1304 	if (!priv)
1305 		return NULL;
1306 	INIT_LIST_HEAD(&priv->list);
1307 	priv->daemon_pid = -1;
1308 	priv->iscsi_transport = tt;
1309 	priv->t.user_scan = iscsi_user_scan;
1310 
1311 	priv->cdev.class = &iscsi_transport_class;
1312 	snprintf(priv->cdev.class_id, BUS_ID_SIZE, "%s", tt->name);
1313 	err = class_device_register(&priv->cdev);
1314 	if (err)
1315 		goto free_priv;
1316 
1317 	err = sysfs_create_group(&priv->cdev.kobj, &iscsi_transport_group);
1318 	if (err)
1319 		goto unregister_cdev;
1320 
1321 	/* host parameters */
1322 	priv->t.host_attrs.ac.attrs = &priv->host_attrs[0];
1323 	priv->t.host_attrs.ac.class = &iscsi_host_class.class;
1324 	priv->t.host_attrs.ac.match = iscsi_host_match;
1325 	priv->t.host_size = sizeof(struct iscsi_host);
1326 	priv->host_attrs[0] = NULL;
1327 	transport_container_register(&priv->t.host_attrs);
1328 
1329 	/* connection parameters */
1330 	priv->conn_cont.ac.attrs = &priv->conn_attrs[0];
1331 	priv->conn_cont.ac.class = &iscsi_connection_class.class;
1332 	priv->conn_cont.ac.match = iscsi_conn_match;
1333 	transport_container_register(&priv->conn_cont);
1334 
1335 	SETUP_CONN_RD_ATTR(max_recv_dlength, ISCSI_MAX_RECV_DLENGTH);
1336 	SETUP_CONN_RD_ATTR(max_xmit_dlength, ISCSI_MAX_XMIT_DLENGTH);
1337 	SETUP_CONN_RD_ATTR(header_digest, ISCSI_HDRDGST_EN);
1338 	SETUP_CONN_RD_ATTR(data_digest, ISCSI_DATADGST_EN);
1339 	SETUP_CONN_RD_ATTR(ifmarker, ISCSI_IFMARKER_EN);
1340 	SETUP_CONN_RD_ATTR(ofmarker, ISCSI_OFMARKER_EN);
1341 	SETUP_CONN_RD_ATTR(address, ISCSI_CONN_ADDRESS);
1342 	SETUP_CONN_RD_ATTR(port, ISCSI_CONN_PORT);
1343 	SETUP_CONN_RD_ATTR(exp_statsn, ISCSI_EXP_STATSN);
1344 	SETUP_CONN_RD_ATTR(persistent_address, ISCSI_PERSISTENT_ADDRESS);
1345 	SETUP_CONN_RD_ATTR(persistent_port, ISCSI_PERSISTENT_PORT);
1346 
1347 	BUG_ON(count > ISCSI_CONN_ATTRS);
1348 	priv->conn_attrs[count] = NULL;
1349 	count = 0;
1350 
1351 	/* session parameters */
1352 	priv->session_cont.ac.attrs = &priv->session_attrs[0];
1353 	priv->session_cont.ac.class = &iscsi_session_class.class;
1354 	priv->session_cont.ac.match = iscsi_session_match;
1355 	transport_container_register(&priv->session_cont);
1356 
1357 	SETUP_SESSION_RD_ATTR(initial_r2t, ISCSI_INITIAL_R2T_EN);
1358 	SETUP_SESSION_RD_ATTR(max_outstanding_r2t, ISCSI_MAX_R2T);
1359 	SETUP_SESSION_RD_ATTR(immediate_data, ISCSI_IMM_DATA_EN);
1360 	SETUP_SESSION_RD_ATTR(first_burst_len, ISCSI_FIRST_BURST);
1361 	SETUP_SESSION_RD_ATTR(max_burst_len, ISCSI_MAX_BURST);
1362 	SETUP_SESSION_RD_ATTR(data_pdu_in_order, ISCSI_PDU_INORDER_EN);
1363 	SETUP_SESSION_RD_ATTR(data_seq_in_order, ISCSI_DATASEQ_INORDER_EN);
1364 	SETUP_SESSION_RD_ATTR(erl, ISCSI_ERL);
1365 	SETUP_SESSION_RD_ATTR(targetname, ISCSI_TARGET_NAME);
1366 	SETUP_SESSION_RD_ATTR(tpgt, ISCSI_TPGT);
1367 	SETUP_PRIV_SESSION_RD_ATTR(recovery_tmo);
1368 
1369 	BUG_ON(count > ISCSI_SESSION_ATTRS);
1370 	priv->session_attrs[count] = NULL;
1371 
1372 	spin_lock_irqsave(&iscsi_transport_lock, flags);
1373 	list_add(&priv->list, &iscsi_transports);
1374 	spin_unlock_irqrestore(&iscsi_transport_lock, flags);
1375 
1376 	printk(KERN_NOTICE "iscsi: registered transport (%s)\n", tt->name);
1377 	return &priv->t;
1378 
1379 unregister_cdev:
1380 	class_device_unregister(&priv->cdev);
1381 free_priv:
1382 	kfree(priv);
1383 	return NULL;
1384 }
1385 EXPORT_SYMBOL_GPL(iscsi_register_transport);
1386 
1387 int iscsi_unregister_transport(struct iscsi_transport *tt)
1388 {
1389 	struct iscsi_internal *priv;
1390 	unsigned long flags;
1391 
1392 	BUG_ON(!tt);
1393 
1394 	mutex_lock(&rx_queue_mutex);
1395 
1396 	priv = iscsi_if_transport_lookup(tt);
1397 	BUG_ON (!priv);
1398 
1399 	spin_lock_irqsave(&iscsi_transport_lock, flags);
1400 	list_del(&priv->list);
1401 	spin_unlock_irqrestore(&iscsi_transport_lock, flags);
1402 
1403 	transport_container_unregister(&priv->conn_cont);
1404 	transport_container_unregister(&priv->session_cont);
1405 	transport_container_unregister(&priv->t.host_attrs);
1406 
1407 	sysfs_remove_group(&priv->cdev.kobj, &iscsi_transport_group);
1408 	class_device_unregister(&priv->cdev);
1409 	mutex_unlock(&rx_queue_mutex);
1410 
1411 	return 0;
1412 }
1413 EXPORT_SYMBOL_GPL(iscsi_unregister_transport);
1414 
1415 static __init int iscsi_transport_init(void)
1416 {
1417 	int err;
1418 
1419 	printk(KERN_INFO "Loading iSCSI transport class v%s.\n",
1420 		ISCSI_TRANSPORT_VERSION);
1421 
1422 	err = class_register(&iscsi_transport_class);
1423 	if (err)
1424 		return err;
1425 
1426 	err = transport_class_register(&iscsi_host_class);
1427 	if (err)
1428 		goto unregister_transport_class;
1429 
1430 	err = transport_class_register(&iscsi_connection_class);
1431 	if (err)
1432 		goto unregister_host_class;
1433 
1434 	err = transport_class_register(&iscsi_session_class);
1435 	if (err)
1436 		goto unregister_conn_class;
1437 
1438 	nls = netlink_kernel_create(NETLINK_ISCSI, 1, iscsi_if_rx,
1439 			THIS_MODULE);
1440 	if (!nls) {
1441 		err = -ENOBUFS;
1442 		goto unregister_session_class;
1443 	}
1444 
1445 	return 0;
1446 
1447 unregister_session_class:
1448 	transport_class_unregister(&iscsi_session_class);
1449 unregister_conn_class:
1450 	transport_class_unregister(&iscsi_connection_class);
1451 unregister_host_class:
1452 	transport_class_unregister(&iscsi_host_class);
1453 unregister_transport_class:
1454 	class_unregister(&iscsi_transport_class);
1455 	return err;
1456 }
1457 
1458 static void __exit iscsi_transport_exit(void)
1459 {
1460 	sock_release(nls->sk_socket);
1461 	transport_class_unregister(&iscsi_connection_class);
1462 	transport_class_unregister(&iscsi_session_class);
1463 	transport_class_unregister(&iscsi_host_class);
1464 	class_unregister(&iscsi_transport_class);
1465 }
1466 
1467 module_init(iscsi_transport_init);
1468 module_exit(iscsi_transport_exit);
1469 
1470 MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, "
1471 	      "Dmitry Yusupov <dmitry_yus@yahoo.com>, "
1472 	      "Alex Aizman <itn780@yahoo.com>");
1473 MODULE_DESCRIPTION("iSCSI Transport Interface");
1474 MODULE_LICENSE("GPL");
1475 MODULE_VERSION(ISCSI_TRANSPORT_VERSION);
1476