xref: /openbmc/linux/drivers/target/tcm_fc/tfc_sess.c (revision 615c36f5) 
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 <generated/utsrelease.h>
23 #include <linux/utsname.h>
24 #include <linux/init.h>
25 #include <linux/slab.h>
26 #include <linux/kthread.h>
27 #include <linux/types.h>
28 #include <linux/string.h>
29 #include <linux/configfs.h>
30 #include <linux/ctype.h>
31 #include <linux/hash.h>
32 #include <linux/rcupdate.h>
33 #include <linux/rculist.h>
34 #include <linux/kref.h>
35 #include <asm/unaligned.h>
36 #include <scsi/scsi.h>
37 #include <scsi/scsi_host.h>
38 #include <scsi/scsi_device.h>
39 #include <scsi/scsi_cmnd.h>
40 #include <scsi/libfc.h>
41 
42 #include <target/target_core_base.h>
43 #include <target/target_core_transport.h>
44 #include <target/target_core_fabric_ops.h>
45 #include <target/target_core_device.h>
46 #include <target/target_core_tpg.h>
47 #include <target/target_core_configfs.h>
48 #include <target/configfs_macros.h>
49 
50 #include "tcm_fc.h"
51 
52 static void ft_sess_delete_all(struct ft_tport *);
53 
54 /*
55  * Lookup or allocate target local port.
56  * Caller holds ft_lport_lock.
57  */
58 static struct ft_tport *ft_tport_create(struct fc_lport *lport)
59 {
60 	struct ft_tpg *tpg;
61 	struct ft_tport *tport;
62 	int i;
63 
64 	tport = rcu_dereference(lport->prov[FC_TYPE_FCP]);
65 	if (tport && tport->tpg)
66 		return tport;
67 
68 	tpg = ft_lport_find_tpg(lport);
69 	if (!tpg)
70 		return NULL;
71 
72 	if (tport) {
73 		tport->tpg = tpg;
74 		return tport;
75 	}
76 
77 	tport = kzalloc(sizeof(*tport), GFP_KERNEL);
78 	if (!tport)
79 		return NULL;
80 
81 	tport->lport = lport;
82 	tport->tpg = tpg;
83 	tpg->tport = tport;
84 	for (i = 0; i < FT_SESS_HASH_SIZE; i++)
85 		INIT_HLIST_HEAD(&tport->hash[i]);
86 
87 	rcu_assign_pointer(lport->prov[FC_TYPE_FCP], tport);
88 	return tport;
89 }
90 
91 /*
92  * Free tport via RCU.
93  */
94 static void ft_tport_rcu_free(struct rcu_head *rcu)
95 {
96 	struct ft_tport *tport = container_of(rcu, struct ft_tport, rcu);
97 
98 	kfree(tport);
99 }
100 
101 /*
102  * Delete a target local port.
103  * Caller holds ft_lport_lock.
104  */
105 static void ft_tport_delete(struct ft_tport *tport)
106 {
107 	struct fc_lport *lport;
108 	struct ft_tpg *tpg;
109 
110 	ft_sess_delete_all(tport);
111 	lport = tport->lport;
112 	BUG_ON(tport != lport->prov[FC_TYPE_FCP]);
113 	rcu_assign_pointer(lport->prov[FC_TYPE_FCP], NULL);
114 
115 	tpg = tport->tpg;
116 	if (tpg) {
117 		tpg->tport = NULL;
118 		tport->tpg = NULL;
119 	}
120 	call_rcu(&tport->rcu, ft_tport_rcu_free);
121 }
122 
123 /*
124  * Add local port.
125  * Called thru fc_lport_iterate().
126  */
127 void ft_lport_add(struct fc_lport *lport, void *arg)
128 {
129 	mutex_lock(&ft_lport_lock);
130 	ft_tport_create(lport);
131 	mutex_unlock(&ft_lport_lock);
132 }
133 
134 /*
135  * Delete local port.
136  * Called thru fc_lport_iterate().
137  */
138 void ft_lport_del(struct fc_lport *lport, void *arg)
139 {
140 	struct ft_tport *tport;
141 
142 	mutex_lock(&ft_lport_lock);
143 	tport = lport->prov[FC_TYPE_FCP];
144 	if (tport)
145 		ft_tport_delete(tport);
146 	mutex_unlock(&ft_lport_lock);
147 }
148 
149 /*
150  * Notification of local port change from libfc.
151  * Create or delete local port and associated tport.
152  */
153 int ft_lport_notify(struct notifier_block *nb, unsigned long event, void *arg)
154 {
155 	struct fc_lport *lport = arg;
156 
157 	switch (event) {
158 	case FC_LPORT_EV_ADD:
159 		ft_lport_add(lport, NULL);
160 		break;
161 	case FC_LPORT_EV_DEL:
162 		ft_lport_del(lport, NULL);
163 		break;
164 	}
165 	return NOTIFY_DONE;
166 }
167 
168 /*
169  * Hash function for FC_IDs.
170  */
171 static u32 ft_sess_hash(u32 port_id)
172 {
173 	return hash_32(port_id, FT_SESS_HASH_BITS);
174 }
175 
176 /*
177  * Find session in local port.
178  * Sessions and hash lists are RCU-protected.
179  * A reference is taken which must be eventually freed.
180  */
181 static struct ft_sess *ft_sess_get(struct fc_lport *lport, u32 port_id)
182 {
183 	struct ft_tport *tport;
184 	struct hlist_head *head;
185 	struct hlist_node *pos;
186 	struct ft_sess *sess;
187 
188 	rcu_read_lock();
189 	tport = rcu_dereference(lport->prov[FC_TYPE_FCP]);
190 	if (!tport)
191 		goto out;
192 
193 	head = &tport->hash[ft_sess_hash(port_id)];
194 	hlist_for_each_entry_rcu(sess, pos, head, hash) {
195 		if (sess->port_id == port_id) {
196 			kref_get(&sess->kref);
197 			rcu_read_unlock();
198 			pr_debug("port_id %x found %p\n", port_id, sess);
199 			return sess;
200 		}
201 	}
202 out:
203 	rcu_read_unlock();
204 	pr_debug("port_id %x not found\n", port_id);
205 	return NULL;
206 }
207 
208 /*
209  * Allocate session and enter it in the hash for the local port.
210  * Caller holds ft_lport_lock.
211  */
212 static struct ft_sess *ft_sess_create(struct ft_tport *tport, u32 port_id,
213 				      struct ft_node_acl *acl)
214 {
215 	struct ft_sess *sess;
216 	struct hlist_head *head;
217 	struct hlist_node *pos;
218 
219 	head = &tport->hash[ft_sess_hash(port_id)];
220 	hlist_for_each_entry_rcu(sess, pos, head, hash)
221 		if (sess->port_id == port_id)
222 			return sess;
223 
224 	sess = kzalloc(sizeof(*sess), GFP_KERNEL);
225 	if (!sess)
226 		return NULL;
227 
228 	sess->se_sess = transport_init_session();
229 	if (IS_ERR(sess->se_sess)) {
230 		kfree(sess);
231 		return NULL;
232 	}
233 	sess->se_sess->se_node_acl = &acl->se_node_acl;
234 	sess->tport = tport;
235 	sess->port_id = port_id;
236 	kref_init(&sess->kref);	/* ref for table entry */
237 	hlist_add_head_rcu(&sess->hash, head);
238 	tport->sess_count++;
239 
240 	pr_debug("port_id %x sess %p\n", port_id, sess);
241 
242 	transport_register_session(&tport->tpg->se_tpg, &acl->se_node_acl,
243 				   sess->se_sess, sess);
244 	return sess;
245 }
246 
247 /*
248  * Unhash the session.
249  * Caller holds ft_lport_lock.
250  */
251 static void ft_sess_unhash(struct ft_sess *sess)
252 {
253 	struct ft_tport *tport = sess->tport;
254 
255 	hlist_del_rcu(&sess->hash);
256 	BUG_ON(!tport->sess_count);
257 	tport->sess_count--;
258 	sess->port_id = -1;
259 	sess->params = 0;
260 }
261 
262 /*
263  * Delete session from hash.
264  * Caller holds ft_lport_lock.
265  */
266 static struct ft_sess *ft_sess_delete(struct ft_tport *tport, u32 port_id)
267 {
268 	struct hlist_head *head;
269 	struct hlist_node *pos;
270 	struct ft_sess *sess;
271 
272 	head = &tport->hash[ft_sess_hash(port_id)];
273 	hlist_for_each_entry_rcu(sess, pos, head, hash) {
274 		if (sess->port_id == port_id) {
275 			ft_sess_unhash(sess);
276 			return sess;
277 		}
278 	}
279 	return NULL;
280 }
281 
282 /*
283  * Delete all sessions from tport.
284  * Caller holds ft_lport_lock.
285  */
286 static void ft_sess_delete_all(struct ft_tport *tport)
287 {
288 	struct hlist_head *head;
289 	struct hlist_node *pos;
290 	struct ft_sess *sess;
291 
292 	for (head = tport->hash;
293 	     head < &tport->hash[FT_SESS_HASH_SIZE]; head++) {
294 		hlist_for_each_entry_rcu(sess, pos, head, hash) {
295 			ft_sess_unhash(sess);
296 			transport_deregister_session_configfs(sess->se_sess);
297 			ft_sess_put(sess);	/* release from table */
298 		}
299 	}
300 }
301 
302 /*
303  * TCM ops for sessions.
304  */
305 
306 /*
307  * Determine whether session is allowed to be shutdown in the current context.
308  * Returns non-zero if the session should be shutdown.
309  */
310 int ft_sess_shutdown(struct se_session *se_sess)
311 {
312 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
313 
314 	pr_debug("port_id %x\n", sess->port_id);
315 	return 1;
316 }
317 
318 /*
319  * Remove session and send PRLO.
320  * This is called when the ACL is being deleted or queue depth is changing.
321  */
322 void ft_sess_close(struct se_session *se_sess)
323 {
324 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
325 	struct fc_lport *lport;
326 	u32 port_id;
327 
328 	mutex_lock(&ft_lport_lock);
329 	lport = sess->tport->lport;
330 	port_id = sess->port_id;
331 	if (port_id == -1) {
332 		mutex_unlock(&ft_lport_lock);
333 		return;
334 	}
335 	pr_debug("port_id %x\n", port_id);
336 	ft_sess_unhash(sess);
337 	mutex_unlock(&ft_lport_lock);
338 	transport_deregister_session_configfs(se_sess);
339 	ft_sess_put(sess);
340 	/* XXX Send LOGO or PRLO */
341 	synchronize_rcu();		/* let transport deregister happen */
342 }
343 
344 void ft_sess_stop(struct se_session *se_sess, int sess_sleep, int conn_sleep)
345 {
346 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
347 
348 	pr_debug("port_id %x\n", sess->port_id);
349 }
350 
351 int ft_sess_logged_in(struct se_session *se_sess)
352 {
353 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
354 
355 	return sess->port_id != -1;
356 }
357 
358 u32 ft_sess_get_index(struct se_session *se_sess)
359 {
360 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
361 
362 	return sess->port_id;	/* XXX TBD probably not what is needed */
363 }
364 
365 u32 ft_sess_get_port_name(struct se_session *se_sess,
366 			  unsigned char *buf, u32 len)
367 {
368 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
369 
370 	return ft_format_wwn(buf, len, sess->port_name);
371 }
372 
373 void ft_sess_set_erl0(struct se_session *se_sess)
374 {
375 	/* XXX TBD called when out of memory */
376 }
377 
378 /*
379  * libfc ops involving sessions.
380  */
381 
382 static int ft_prli_locked(struct fc_rport_priv *rdata, u32 spp_len,
383 			  const struct fc_els_spp *rspp, struct fc_els_spp *spp)
384 {
385 	struct ft_tport *tport;
386 	struct ft_sess *sess;
387 	struct ft_node_acl *acl;
388 	u32 fcp_parm;
389 
390 	tport = ft_tport_create(rdata->local_port);
391 	if (!tport)
392 		return 0;	/* not a target for this local port */
393 
394 	acl = ft_acl_get(tport->tpg, rdata);
395 	if (!acl)
396 		return 0;
397 
398 	if (!rspp)
399 		goto fill;
400 
401 	if (rspp->spp_flags & (FC_SPP_OPA_VAL | FC_SPP_RPA_VAL))
402 		return FC_SPP_RESP_NO_PA;
403 
404 	/*
405 	 * If both target and initiator bits are off, the SPP is invalid.
406 	 */
407 	fcp_parm = ntohl(rspp->spp_params);
408 	if (!(fcp_parm & (FCP_SPPF_INIT_FCN | FCP_SPPF_TARG_FCN)))
409 		return FC_SPP_RESP_INVL;
410 
411 	/*
412 	 * Create session (image pair) only if requested by
413 	 * EST_IMG_PAIR flag and if the requestor is an initiator.
414 	 */
415 	if (rspp->spp_flags & FC_SPP_EST_IMG_PAIR) {
416 		spp->spp_flags |= FC_SPP_EST_IMG_PAIR;
417 		if (!(fcp_parm & FCP_SPPF_INIT_FCN))
418 			return FC_SPP_RESP_CONF;
419 		sess = ft_sess_create(tport, rdata->ids.port_id, acl);
420 		if (!sess)
421 			return FC_SPP_RESP_RES;
422 		if (!sess->params)
423 			rdata->prli_count++;
424 		sess->params = fcp_parm;
425 		sess->port_name = rdata->ids.port_name;
426 		sess->max_frame = rdata->maxframe_size;
427 
428 		/* XXX TBD - clearing actions.  unit attn, see 4.10 */
429 	}
430 
431 	/*
432 	 * OR in our service parameters with other provider (initiator), if any.
433 	 * TBD XXX - indicate RETRY capability?
434 	 */
435 fill:
436 	fcp_parm = ntohl(spp->spp_params);
437 	spp->spp_params = htonl(fcp_parm | FCP_SPPF_TARG_FCN);
438 	return FC_SPP_RESP_ACK;
439 }
440 
441 /**
442  * tcm_fcp_prli() - Handle incoming or outgoing PRLI for the FCP target
443  * @rdata: remote port private
444  * @spp_len: service parameter page length
445  * @rspp: received service parameter page (NULL for outgoing PRLI)
446  * @spp: response service parameter page
447  *
448  * Returns spp response code.
449  */
450 static int ft_prli(struct fc_rport_priv *rdata, u32 spp_len,
451 		   const struct fc_els_spp *rspp, struct fc_els_spp *spp)
452 {
453 	int ret;
454 
455 	mutex_lock(&ft_lport_lock);
456 	ret = ft_prli_locked(rdata, spp_len, rspp, spp);
457 	mutex_unlock(&ft_lport_lock);
458 	pr_debug("port_id %x flags %x ret %x\n",
459 	       rdata->ids.port_id, rspp ? rspp->spp_flags : 0, ret);
460 	return ret;
461 }
462 
463 static void ft_sess_rcu_free(struct rcu_head *rcu)
464 {
465 	struct ft_sess *sess = container_of(rcu, struct ft_sess, rcu);
466 
467 	transport_deregister_session(sess->se_sess);
468 	kfree(sess);
469 }
470 
471 static void ft_sess_free(struct kref *kref)
472 {
473 	struct ft_sess *sess = container_of(kref, struct ft_sess, kref);
474 
475 	call_rcu(&sess->rcu, ft_sess_rcu_free);
476 }
477 
478 void ft_sess_put(struct ft_sess *sess)
479 {
480 	int sess_held = atomic_read(&sess->kref.refcount);
481 
482 	BUG_ON(!sess_held);
483 	kref_put(&sess->kref, ft_sess_free);
484 }
485 
486 static void ft_prlo(struct fc_rport_priv *rdata)
487 {
488 	struct ft_sess *sess;
489 	struct ft_tport *tport;
490 
491 	mutex_lock(&ft_lport_lock);
492 	tport = rcu_dereference(rdata->local_port->prov[FC_TYPE_FCP]);
493 	if (!tport) {
494 		mutex_unlock(&ft_lport_lock);
495 		return;
496 	}
497 	sess = ft_sess_delete(tport, rdata->ids.port_id);
498 	if (!sess) {
499 		mutex_unlock(&ft_lport_lock);
500 		return;
501 	}
502 	mutex_unlock(&ft_lport_lock);
503 	transport_deregister_session_configfs(sess->se_sess);
504 	ft_sess_put(sess);		/* release from table */
505 	rdata->prli_count--;
506 	/* XXX TBD - clearing actions.  unit attn, see 4.10 */
507 }
508 
509 /*
510  * Handle incoming FCP request.
511  * Caller has verified that the frame is type FCP.
512  */
513 static void ft_recv(struct fc_lport *lport, struct fc_frame *fp)
514 {
515 	struct ft_sess *sess;
516 	u32 sid = fc_frame_sid(fp);
517 
518 	pr_debug("sid %x\n", sid);
519 
520 	sess = ft_sess_get(lport, sid);
521 	if (!sess) {
522 		pr_debug("sid %x sess lookup failed\n", sid);
523 		/* TBD XXX - if FCP_CMND, send PRLO */
524 		fc_frame_free(fp);
525 		return;
526 	}
527 	ft_recv_req(sess, fp);	/* must do ft_sess_put() */
528 }
529 
530 /*
531  * Provider ops for libfc.
532  */
533 struct fc4_prov ft_prov = {
534 	.prli = ft_prli,
535 	.prlo = ft_prlo,
536 	.recv = ft_recv,
537 	.module = THIS_MODULE,
538 };
539