xref: /openbmc/linux/drivers/target/tcm_fc/tfc_sess.c (revision 9c1f8594) 
1 /*
2  * Copyright (c) 2010 Cisco Systems, Inc.
3  *
4  * This program is free software; you can redistribute it and/or modify it
5  * under the terms and conditions of the GNU General Public License,
6  * version 2, as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope it will be useful, but WITHOUT
9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
11  * more details.
12  *
13  * You should have received a copy of the GNU General Public License along with
14  * this program; if not, write to the Free Software Foundation, Inc.,
15  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
16  */
17 
18 /* XXX TBD some includes may be extraneous */
19 
20 #include <linux/module.h>
21 #include <linux/moduleparam.h>
22 #include <linux/version.h>
23 #include <generated/utsrelease.h>
24 #include <linux/utsname.h>
25 #include <linux/init.h>
26 #include <linux/slab.h>
27 #include <linux/kthread.h>
28 #include <linux/types.h>
29 #include <linux/string.h>
30 #include <linux/configfs.h>
31 #include <linux/ctype.h>
32 #include <linux/hash.h>
33 #include <linux/rcupdate.h>
34 #include <linux/rculist.h>
35 #include <linux/kref.h>
36 #include <asm/unaligned.h>
37 #include <scsi/scsi.h>
38 #include <scsi/scsi_host.h>
39 #include <scsi/scsi_device.h>
40 #include <scsi/scsi_cmnd.h>
41 #include <scsi/libfc.h>
42 
43 #include <target/target_core_base.h>
44 #include <target/target_core_transport.h>
45 #include <target/target_core_fabric_ops.h>
46 #include <target/target_core_device.h>
47 #include <target/target_core_tpg.h>
48 #include <target/target_core_configfs.h>
49 #include <target/configfs_macros.h>
50 
51 #include "tcm_fc.h"
52 
53 static void ft_sess_delete_all(struct ft_tport *);
54 
55 /*
56  * Lookup or allocate target local port.
57  * Caller holds ft_lport_lock.
58  */
59 static struct ft_tport *ft_tport_create(struct fc_lport *lport)
60 {
61 	struct ft_tpg *tpg;
62 	struct ft_tport *tport;
63 	int i;
64 
65 	tport = rcu_dereference(lport->prov[FC_TYPE_FCP]);
66 	if (tport && tport->tpg)
67 		return tport;
68 
69 	tpg = ft_lport_find_tpg(lport);
70 	if (!tpg)
71 		return NULL;
72 
73 	if (tport) {
74 		tport->tpg = tpg;
75 		return tport;
76 	}
77 
78 	tport = kzalloc(sizeof(*tport), GFP_KERNEL);
79 	if (!tport)
80 		return NULL;
81 
82 	tport->lport = lport;
83 	tport->tpg = tpg;
84 	tpg->tport = tport;
85 	for (i = 0; i < FT_SESS_HASH_SIZE; i++)
86 		INIT_HLIST_HEAD(&tport->hash[i]);
87 
88 	rcu_assign_pointer(lport->prov[FC_TYPE_FCP], tport);
89 	return tport;
90 }
91 
92 /*
93  * Free tport via RCU.
94  */
95 static void ft_tport_rcu_free(struct rcu_head *rcu)
96 {
97 	struct ft_tport *tport = container_of(rcu, struct ft_tport, rcu);
98 
99 	kfree(tport);
100 }
101 
102 /*
103  * Delete a target local port.
104  * Caller holds ft_lport_lock.
105  */
106 static void ft_tport_delete(struct ft_tport *tport)
107 {
108 	struct fc_lport *lport;
109 	struct ft_tpg *tpg;
110 
111 	ft_sess_delete_all(tport);
112 	lport = tport->lport;
113 	BUG_ON(tport != lport->prov[FC_TYPE_FCP]);
114 	rcu_assign_pointer(lport->prov[FC_TYPE_FCP], NULL);
115 
116 	tpg = tport->tpg;
117 	if (tpg) {
118 		tpg->tport = NULL;
119 		tport->tpg = NULL;
120 	}
121 	call_rcu(&tport->rcu, ft_tport_rcu_free);
122 }
123 
124 /*
125  * Add local port.
126  * Called thru fc_lport_iterate().
127  */
128 void ft_lport_add(struct fc_lport *lport, void *arg)
129 {
130 	mutex_lock(&ft_lport_lock);
131 	ft_tport_create(lport);
132 	mutex_unlock(&ft_lport_lock);
133 }
134 
135 /*
136  * Delete local port.
137  * Called thru fc_lport_iterate().
138  */
139 void ft_lport_del(struct fc_lport *lport, void *arg)
140 {
141 	struct ft_tport *tport;
142 
143 	mutex_lock(&ft_lport_lock);
144 	tport = lport->prov[FC_TYPE_FCP];
145 	if (tport)
146 		ft_tport_delete(tport);
147 	mutex_unlock(&ft_lport_lock);
148 }
149 
150 /*
151  * Notification of local port change from libfc.
152  * Create or delete local port and associated tport.
153  */
154 int ft_lport_notify(struct notifier_block *nb, unsigned long event, void *arg)
155 {
156 	struct fc_lport *lport = arg;
157 
158 	switch (event) {
159 	case FC_LPORT_EV_ADD:
160 		ft_lport_add(lport, NULL);
161 		break;
162 	case FC_LPORT_EV_DEL:
163 		ft_lport_del(lport, NULL);
164 		break;
165 	}
166 	return NOTIFY_DONE;
167 }
168 
169 /*
170  * Hash function for FC_IDs.
171  */
172 static u32 ft_sess_hash(u32 port_id)
173 {
174 	return hash_32(port_id, FT_SESS_HASH_BITS);
175 }
176 
177 /*
178  * Find session in local port.
179  * Sessions and hash lists are RCU-protected.
180  * A reference is taken which must be eventually freed.
181  */
182 static struct ft_sess *ft_sess_get(struct fc_lport *lport, u32 port_id)
183 {
184 	struct ft_tport *tport;
185 	struct hlist_head *head;
186 	struct hlist_node *pos;
187 	struct ft_sess *sess;
188 
189 	rcu_read_lock();
190 	tport = rcu_dereference(lport->prov[FC_TYPE_FCP]);
191 	if (!tport)
192 		goto out;
193 
194 	head = &tport->hash[ft_sess_hash(port_id)];
195 	hlist_for_each_entry_rcu(sess, pos, head, hash) {
196 		if (sess->port_id == port_id) {
197 			kref_get(&sess->kref);
198 			rcu_read_unlock();
199 			pr_debug("port_id %x found %p\n", port_id, sess);
200 			return sess;
201 		}
202 	}
203 out:
204 	rcu_read_unlock();
205 	pr_debug("port_id %x not found\n", port_id);
206 	return NULL;
207 }
208 
209 /*
210  * Allocate session and enter it in the hash for the local port.
211  * Caller holds ft_lport_lock.
212  */
213 static struct ft_sess *ft_sess_create(struct ft_tport *tport, u32 port_id,
214 				      struct ft_node_acl *acl)
215 {
216 	struct ft_sess *sess;
217 	struct hlist_head *head;
218 	struct hlist_node *pos;
219 
220 	head = &tport->hash[ft_sess_hash(port_id)];
221 	hlist_for_each_entry_rcu(sess, pos, head, hash)
222 		if (sess->port_id == port_id)
223 			return sess;
224 
225 	sess = kzalloc(sizeof(*sess), GFP_KERNEL);
226 	if (!sess)
227 		return NULL;
228 
229 	sess->se_sess = transport_init_session();
230 	if (IS_ERR(sess->se_sess)) {
231 		kfree(sess);
232 		return NULL;
233 	}
234 	sess->se_sess->se_node_acl = &acl->se_node_acl;
235 	sess->tport = tport;
236 	sess->port_id = port_id;
237 	kref_init(&sess->kref);	/* ref for table entry */
238 	hlist_add_head_rcu(&sess->hash, head);
239 	tport->sess_count++;
240 
241 	pr_debug("port_id %x sess %p\n", port_id, sess);
242 
243 	transport_register_session(&tport->tpg->se_tpg, &acl->se_node_acl,
244 				   sess->se_sess, sess);
245 	return sess;
246 }
247 
248 /*
249  * Unhash the session.
250  * Caller holds ft_lport_lock.
251  */
252 static void ft_sess_unhash(struct ft_sess *sess)
253 {
254 	struct ft_tport *tport = sess->tport;
255 
256 	hlist_del_rcu(&sess->hash);
257 	BUG_ON(!tport->sess_count);
258 	tport->sess_count--;
259 	sess->port_id = -1;
260 	sess->params = 0;
261 }
262 
263 /*
264  * Delete session from hash.
265  * Caller holds ft_lport_lock.
266  */
267 static struct ft_sess *ft_sess_delete(struct ft_tport *tport, u32 port_id)
268 {
269 	struct hlist_head *head;
270 	struct hlist_node *pos;
271 	struct ft_sess *sess;
272 
273 	head = &tport->hash[ft_sess_hash(port_id)];
274 	hlist_for_each_entry_rcu(sess, pos, head, hash) {
275 		if (sess->port_id == port_id) {
276 			ft_sess_unhash(sess);
277 			return sess;
278 		}
279 	}
280 	return NULL;
281 }
282 
283 /*
284  * Delete all sessions from tport.
285  * Caller holds ft_lport_lock.
286  */
287 static void ft_sess_delete_all(struct ft_tport *tport)
288 {
289 	struct hlist_head *head;
290 	struct hlist_node *pos;
291 	struct ft_sess *sess;
292 
293 	for (head = tport->hash;
294 	     head < &tport->hash[FT_SESS_HASH_SIZE]; head++) {
295 		hlist_for_each_entry_rcu(sess, pos, head, hash) {
296 			ft_sess_unhash(sess);
297 			transport_deregister_session_configfs(sess->se_sess);
298 			ft_sess_put(sess);	/* release from table */
299 		}
300 	}
301 }
302 
303 /*
304  * TCM ops for sessions.
305  */
306 
307 /*
308  * Determine whether session is allowed to be shutdown in the current context.
309  * Returns non-zero if the session should be shutdown.
310  */
311 int ft_sess_shutdown(struct se_session *se_sess)
312 {
313 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
314 
315 	pr_debug("port_id %x\n", sess->port_id);
316 	return 1;
317 }
318 
319 /*
320  * Remove session and send PRLO.
321  * This is called when the ACL is being deleted or queue depth is changing.
322  */
323 void ft_sess_close(struct se_session *se_sess)
324 {
325 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
326 	struct fc_lport *lport;
327 	u32 port_id;
328 
329 	mutex_lock(&ft_lport_lock);
330 	lport = sess->tport->lport;
331 	port_id = sess->port_id;
332 	if (port_id == -1) {
333 		mutex_unlock(&ft_lport_lock);
334 		return;
335 	}
336 	pr_debug("port_id %x\n", port_id);
337 	ft_sess_unhash(sess);
338 	mutex_unlock(&ft_lport_lock);
339 	transport_deregister_session_configfs(se_sess);
340 	ft_sess_put(sess);
341 	/* XXX Send LOGO or PRLO */
342 	synchronize_rcu();		/* let transport deregister happen */
343 }
344 
345 void ft_sess_stop(struct se_session *se_sess, int sess_sleep, int conn_sleep)
346 {
347 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
348 
349 	pr_debug("port_id %x\n", sess->port_id);
350 }
351 
352 int ft_sess_logged_in(struct se_session *se_sess)
353 {
354 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
355 
356 	return sess->port_id != -1;
357 }
358 
359 u32 ft_sess_get_index(struct se_session *se_sess)
360 {
361 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
362 
363 	return sess->port_id;	/* XXX TBD probably not what is needed */
364 }
365 
366 u32 ft_sess_get_port_name(struct se_session *se_sess,
367 			  unsigned char *buf, u32 len)
368 {
369 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
370 
371 	return ft_format_wwn(buf, len, sess->port_name);
372 }
373 
374 void ft_sess_set_erl0(struct se_session *se_sess)
375 {
376 	/* XXX TBD called when out of memory */
377 }
378 
379 /*
380  * libfc ops involving sessions.
381  */
382 
383 static int ft_prli_locked(struct fc_rport_priv *rdata, u32 spp_len,
384 			  const struct fc_els_spp *rspp, struct fc_els_spp *spp)
385 {
386 	struct ft_tport *tport;
387 	struct ft_sess *sess;
388 	struct ft_node_acl *acl;
389 	u32 fcp_parm;
390 
391 	tport = ft_tport_create(rdata->local_port);
392 	if (!tport)
393 		return 0;	/* not a target for this local port */
394 
395 	acl = ft_acl_get(tport->tpg, rdata);
396 	if (!acl)
397 		return 0;
398 
399 	if (!rspp)
400 		goto fill;
401 
402 	if (rspp->spp_flags & (FC_SPP_OPA_VAL | FC_SPP_RPA_VAL))
403 		return FC_SPP_RESP_NO_PA;
404 
405 	/*
406 	 * If both target and initiator bits are off, the SPP is invalid.
407 	 */
408 	fcp_parm = ntohl(rspp->spp_params);
409 	if (!(fcp_parm & (FCP_SPPF_INIT_FCN | FCP_SPPF_TARG_FCN)))
410 		return FC_SPP_RESP_INVL;
411 
412 	/*
413 	 * Create session (image pair) only if requested by
414 	 * EST_IMG_PAIR flag and if the requestor is an initiator.
415 	 */
416 	if (rspp->spp_flags & FC_SPP_EST_IMG_PAIR) {
417 		spp->spp_flags |= FC_SPP_EST_IMG_PAIR;
418 		if (!(fcp_parm & FCP_SPPF_INIT_FCN))
419 			return FC_SPP_RESP_CONF;
420 		sess = ft_sess_create(tport, rdata->ids.port_id, acl);
421 		if (!sess)
422 			return FC_SPP_RESP_RES;
423 		if (!sess->params)
424 			rdata->prli_count++;
425 		sess->params = fcp_parm;
426 		sess->port_name = rdata->ids.port_name;
427 		sess->max_frame = rdata->maxframe_size;
428 
429 		/* XXX TBD - clearing actions.  unit attn, see 4.10 */
430 	}
431 
432 	/*
433 	 * OR in our service parameters with other provider (initiator), if any.
434 	 * TBD XXX - indicate RETRY capability?
435 	 */
436 fill:
437 	fcp_parm = ntohl(spp->spp_params);
438 	spp->spp_params = htonl(fcp_parm | FCP_SPPF_TARG_FCN);
439 	return FC_SPP_RESP_ACK;
440 }
441 
442 /**
443  * tcm_fcp_prli() - Handle incoming or outgoing PRLI for the FCP target
444  * @rdata: remote port private
445  * @spp_len: service parameter page length
446  * @rspp: received service parameter page (NULL for outgoing PRLI)
447  * @spp: response service parameter page
448  *
449  * Returns spp response code.
450  */
451 static int ft_prli(struct fc_rport_priv *rdata, u32 spp_len,
452 		   const struct fc_els_spp *rspp, struct fc_els_spp *spp)
453 {
454 	int ret;
455 
456 	mutex_lock(&ft_lport_lock);
457 	ret = ft_prli_locked(rdata, spp_len, rspp, spp);
458 	mutex_unlock(&ft_lport_lock);
459 	pr_debug("port_id %x flags %x ret %x\n",
460 	       rdata->ids.port_id, rspp ? rspp->spp_flags : 0, ret);
461 	return ret;
462 }
463 
464 static void ft_sess_rcu_free(struct rcu_head *rcu)
465 {
466 	struct ft_sess *sess = container_of(rcu, struct ft_sess, rcu);
467 
468 	transport_deregister_session(sess->se_sess);
469 	kfree(sess);
470 }
471 
472 static void ft_sess_free(struct kref *kref)
473 {
474 	struct ft_sess *sess = container_of(kref, struct ft_sess, kref);
475 
476 	call_rcu(&sess->rcu, ft_sess_rcu_free);
477 }
478 
479 void ft_sess_put(struct ft_sess *sess)
480 {
481 	int sess_held = atomic_read(&sess->kref.refcount);
482 
483 	BUG_ON(!sess_held);
484 	kref_put(&sess->kref, ft_sess_free);
485 }
486 
487 static void ft_prlo(struct fc_rport_priv *rdata)
488 {
489 	struct ft_sess *sess;
490 	struct ft_tport *tport;
491 
492 	mutex_lock(&ft_lport_lock);
493 	tport = rcu_dereference(rdata->local_port->prov[FC_TYPE_FCP]);
494 	if (!tport) {
495 		mutex_unlock(&ft_lport_lock);
496 		return;
497 	}
498 	sess = ft_sess_delete(tport, rdata->ids.port_id);
499 	if (!sess) {
500 		mutex_unlock(&ft_lport_lock);
501 		return;
502 	}
503 	mutex_unlock(&ft_lport_lock);
504 	transport_deregister_session_configfs(sess->se_sess);
505 	ft_sess_put(sess);		/* release from table */
506 	rdata->prli_count--;
507 	/* XXX TBD - clearing actions.  unit attn, see 4.10 */
508 }
509 
510 /*
511  * Handle incoming FCP request.
512  * Caller has verified that the frame is type FCP.
513  */
514 static void ft_recv(struct fc_lport *lport, struct fc_frame *fp)
515 {
516 	struct ft_sess *sess;
517 	u32 sid = fc_frame_sid(fp);
518 
519 	pr_debug("sid %x\n", sid);
520 
521 	sess = ft_sess_get(lport, sid);
522 	if (!sess) {
523 		pr_debug("sid %x sess lookup failed\n", sid);
524 		/* TBD XXX - if FCP_CMND, send PRLO */
525 		fc_frame_free(fp);
526 		return;
527 	}
528 	ft_recv_req(sess, fp);	/* must do ft_sess_put() */
529 }
530 
531 /*
532  * Provider ops for libfc.
533  */
534 struct fc4_prov ft_prov = {
535 	.prli = ft_prli,
536 	.prlo = ft_prlo,
537 	.recv = ft_recv,
538 	.module = THIS_MODULE,
539 };
540