xref: /openbmc/linux/drivers/target/tcm_fc/tfc_sess.c (revision b6bec26c) 
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/utsname.h>
23 #include <linux/init.h>
24 #include <linux/slab.h>
25 #include <linux/kthread.h>
26 #include <linux/types.h>
27 #include <linux/string.h>
28 #include <linux/configfs.h>
29 #include <linux/ctype.h>
30 #include <linux/hash.h>
31 #include <linux/rcupdate.h>
32 #include <linux/rculist.h>
33 #include <linux/kref.h>
34 #include <asm/unaligned.h>
35 #include <scsi/scsi.h>
36 #include <scsi/scsi_host.h>
37 #include <scsi/scsi_device.h>
38 #include <scsi/scsi_cmnd.h>
39 #include <scsi/libfc.h>
40 
41 #include <target/target_core_base.h>
42 #include <target/target_core_fabric.h>
43 #include <target/target_core_configfs.h>
44 #include <target/configfs_macros.h>
45 
46 #include "tcm_fc.h"
47 
48 static void ft_sess_delete_all(struct ft_tport *);
49 
50 /*
51  * Lookup or allocate target local port.
52  * Caller holds ft_lport_lock.
53  */
54 static struct ft_tport *ft_tport_create(struct fc_lport *lport)
55 {
56 	struct ft_tpg *tpg;
57 	struct ft_tport *tport;
58 	int i;
59 
60 	tport = rcu_dereference_protected(lport->prov[FC_TYPE_FCP],
61 					  lockdep_is_held(&ft_lport_lock));
62 	if (tport && tport->tpg)
63 		return tport;
64 
65 	tpg = ft_lport_find_tpg(lport);
66 	if (!tpg)
67 		return NULL;
68 
69 	if (tport) {
70 		tport->tpg = tpg;
71 		return tport;
72 	}
73 
74 	tport = kzalloc(sizeof(*tport), GFP_KERNEL);
75 	if (!tport)
76 		return NULL;
77 
78 	tport->lport = lport;
79 	tport->tpg = tpg;
80 	tpg->tport = tport;
81 	for (i = 0; i < FT_SESS_HASH_SIZE; i++)
82 		INIT_HLIST_HEAD(&tport->hash[i]);
83 
84 	rcu_assign_pointer(lport->prov[FC_TYPE_FCP], tport);
85 	return tport;
86 }
87 
88 /*
89  * Delete a target local port.
90  * Caller holds ft_lport_lock.
91  */
92 static void ft_tport_delete(struct ft_tport *tport)
93 {
94 	struct fc_lport *lport;
95 	struct ft_tpg *tpg;
96 
97 	ft_sess_delete_all(tport);
98 	lport = tport->lport;
99 	BUG_ON(tport != lport->prov[FC_TYPE_FCP]);
100 	rcu_assign_pointer(lport->prov[FC_TYPE_FCP], NULL);
101 
102 	tpg = tport->tpg;
103 	if (tpg) {
104 		tpg->tport = NULL;
105 		tport->tpg = NULL;
106 	}
107 	kfree_rcu(tport, rcu);
108 }
109 
110 /*
111  * Add local port.
112  * Called thru fc_lport_iterate().
113  */
114 void ft_lport_add(struct fc_lport *lport, void *arg)
115 {
116 	mutex_lock(&ft_lport_lock);
117 	ft_tport_create(lport);
118 	mutex_unlock(&ft_lport_lock);
119 }
120 
121 /*
122  * Delete local port.
123  * Called thru fc_lport_iterate().
124  */
125 void ft_lport_del(struct fc_lport *lport, void *arg)
126 {
127 	struct ft_tport *tport;
128 
129 	mutex_lock(&ft_lport_lock);
130 	tport = lport->prov[FC_TYPE_FCP];
131 	if (tport)
132 		ft_tport_delete(tport);
133 	mutex_unlock(&ft_lport_lock);
134 }
135 
136 /*
137  * Notification of local port change from libfc.
138  * Create or delete local port and associated tport.
139  */
140 int ft_lport_notify(struct notifier_block *nb, unsigned long event, void *arg)
141 {
142 	struct fc_lport *lport = arg;
143 
144 	switch (event) {
145 	case FC_LPORT_EV_ADD:
146 		ft_lport_add(lport, NULL);
147 		break;
148 	case FC_LPORT_EV_DEL:
149 		ft_lport_del(lport, NULL);
150 		break;
151 	}
152 	return NOTIFY_DONE;
153 }
154 
155 /*
156  * Hash function for FC_IDs.
157  */
158 static u32 ft_sess_hash(u32 port_id)
159 {
160 	return hash_32(port_id, FT_SESS_HASH_BITS);
161 }
162 
163 /*
164  * Find session in local port.
165  * Sessions and hash lists are RCU-protected.
166  * A reference is taken which must be eventually freed.
167  */
168 static struct ft_sess *ft_sess_get(struct fc_lport *lport, u32 port_id)
169 {
170 	struct ft_tport *tport;
171 	struct hlist_head *head;
172 	struct hlist_node *pos;
173 	struct ft_sess *sess;
174 
175 	rcu_read_lock();
176 	tport = rcu_dereference(lport->prov[FC_TYPE_FCP]);
177 	if (!tport)
178 		goto out;
179 
180 	head = &tport->hash[ft_sess_hash(port_id)];
181 	hlist_for_each_entry_rcu(sess, pos, head, hash) {
182 		if (sess->port_id == port_id) {
183 			kref_get(&sess->kref);
184 			rcu_read_unlock();
185 			pr_debug("port_id %x found %p\n", port_id, sess);
186 			return sess;
187 		}
188 	}
189 out:
190 	rcu_read_unlock();
191 	pr_debug("port_id %x not found\n", port_id);
192 	return NULL;
193 }
194 
195 /*
196  * Allocate session and enter it in the hash for the local port.
197  * Caller holds ft_lport_lock.
198  */
199 static struct ft_sess *ft_sess_create(struct ft_tport *tport, u32 port_id,
200 				      struct ft_node_acl *acl)
201 {
202 	struct ft_sess *sess;
203 	struct hlist_head *head;
204 	struct hlist_node *pos;
205 
206 	head = &tport->hash[ft_sess_hash(port_id)];
207 	hlist_for_each_entry_rcu(sess, pos, head, hash)
208 		if (sess->port_id == port_id)
209 			return sess;
210 
211 	sess = kzalloc(sizeof(*sess), GFP_KERNEL);
212 	if (!sess)
213 		return NULL;
214 
215 	sess->se_sess = transport_init_session();
216 	if (IS_ERR(sess->se_sess)) {
217 		kfree(sess);
218 		return NULL;
219 	}
220 	sess->se_sess->se_node_acl = &acl->se_node_acl;
221 	sess->tport = tport;
222 	sess->port_id = port_id;
223 	kref_init(&sess->kref);	/* ref for table entry */
224 	hlist_add_head_rcu(&sess->hash, head);
225 	tport->sess_count++;
226 
227 	pr_debug("port_id %x sess %p\n", port_id, sess);
228 
229 	transport_register_session(&tport->tpg->se_tpg, &acl->se_node_acl,
230 				   sess->se_sess, sess);
231 	return sess;
232 }
233 
234 /*
235  * Unhash the session.
236  * Caller holds ft_lport_lock.
237  */
238 static void ft_sess_unhash(struct ft_sess *sess)
239 {
240 	struct ft_tport *tport = sess->tport;
241 
242 	hlist_del_rcu(&sess->hash);
243 	BUG_ON(!tport->sess_count);
244 	tport->sess_count--;
245 	sess->port_id = -1;
246 	sess->params = 0;
247 }
248 
249 /*
250  * Delete session from hash.
251  * Caller holds ft_lport_lock.
252  */
253 static struct ft_sess *ft_sess_delete(struct ft_tport *tport, u32 port_id)
254 {
255 	struct hlist_head *head;
256 	struct hlist_node *pos;
257 	struct ft_sess *sess;
258 
259 	head = &tport->hash[ft_sess_hash(port_id)];
260 	hlist_for_each_entry_rcu(sess, pos, head, hash) {
261 		if (sess->port_id == port_id) {
262 			ft_sess_unhash(sess);
263 			return sess;
264 		}
265 	}
266 	return NULL;
267 }
268 
269 /*
270  * Delete all sessions from tport.
271  * Caller holds ft_lport_lock.
272  */
273 static void ft_sess_delete_all(struct ft_tport *tport)
274 {
275 	struct hlist_head *head;
276 	struct hlist_node *pos;
277 	struct ft_sess *sess;
278 
279 	for (head = tport->hash;
280 	     head < &tport->hash[FT_SESS_HASH_SIZE]; head++) {
281 		hlist_for_each_entry_rcu(sess, pos, head, hash) {
282 			ft_sess_unhash(sess);
283 			transport_deregister_session_configfs(sess->se_sess);
284 			ft_sess_put(sess);	/* release from table */
285 		}
286 	}
287 }
288 
289 /*
290  * TCM ops for sessions.
291  */
292 
293 /*
294  * Determine whether session is allowed to be shutdown in the current context.
295  * Returns non-zero if the session should be shutdown.
296  */
297 int ft_sess_shutdown(struct se_session *se_sess)
298 {
299 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
300 
301 	pr_debug("port_id %x\n", sess->port_id);
302 	return 1;
303 }
304 
305 /*
306  * Remove session and send PRLO.
307  * This is called when the ACL is being deleted or queue depth is changing.
308  */
309 void ft_sess_close(struct se_session *se_sess)
310 {
311 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
312 	u32 port_id;
313 
314 	mutex_lock(&ft_lport_lock);
315 	port_id = sess->port_id;
316 	if (port_id == -1) {
317 		mutex_unlock(&ft_lport_lock);
318 		return;
319 	}
320 	pr_debug("port_id %x\n", port_id);
321 	ft_sess_unhash(sess);
322 	mutex_unlock(&ft_lport_lock);
323 	transport_deregister_session_configfs(se_sess);
324 	ft_sess_put(sess);
325 	/* XXX Send LOGO or PRLO */
326 	synchronize_rcu();		/* let transport deregister happen */
327 }
328 
329 u32 ft_sess_get_index(struct se_session *se_sess)
330 {
331 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
332 
333 	return sess->port_id;	/* XXX TBD probably not what is needed */
334 }
335 
336 u32 ft_sess_get_port_name(struct se_session *se_sess,
337 			  unsigned char *buf, u32 len)
338 {
339 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
340 
341 	return ft_format_wwn(buf, len, sess->port_name);
342 }
343 
344 /*
345  * libfc ops involving sessions.
346  */
347 
348 static int ft_prli_locked(struct fc_rport_priv *rdata, u32 spp_len,
349 			  const struct fc_els_spp *rspp, struct fc_els_spp *spp)
350 {
351 	struct ft_tport *tport;
352 	struct ft_sess *sess;
353 	struct ft_node_acl *acl;
354 	u32 fcp_parm;
355 
356 	tport = ft_tport_create(rdata->local_port);
357 	if (!tport)
358 		goto not_target;	/* not a target for this local port */
359 
360 	acl = ft_acl_get(tport->tpg, rdata);
361 	if (!acl)
362 		goto not_target;	/* no target for this remote */
363 
364 	if (!rspp)
365 		goto fill;
366 
367 	if (rspp->spp_flags & (FC_SPP_OPA_VAL | FC_SPP_RPA_VAL))
368 		return FC_SPP_RESP_NO_PA;
369 
370 	/*
371 	 * If both target and initiator bits are off, the SPP is invalid.
372 	 */
373 	fcp_parm = ntohl(rspp->spp_params);
374 	if (!(fcp_parm & (FCP_SPPF_INIT_FCN | FCP_SPPF_TARG_FCN)))
375 		return FC_SPP_RESP_INVL;
376 
377 	/*
378 	 * Create session (image pair) only if requested by
379 	 * EST_IMG_PAIR flag and if the requestor is an initiator.
380 	 */
381 	if (rspp->spp_flags & FC_SPP_EST_IMG_PAIR) {
382 		spp->spp_flags |= FC_SPP_EST_IMG_PAIR;
383 		if (!(fcp_parm & FCP_SPPF_INIT_FCN))
384 			return FC_SPP_RESP_CONF;
385 		sess = ft_sess_create(tport, rdata->ids.port_id, acl);
386 		if (!sess)
387 			return FC_SPP_RESP_RES;
388 		if (!sess->params)
389 			rdata->prli_count++;
390 		sess->params = fcp_parm;
391 		sess->port_name = rdata->ids.port_name;
392 		sess->max_frame = rdata->maxframe_size;
393 
394 		/* XXX TBD - clearing actions.  unit attn, see 4.10 */
395 	}
396 
397 	/*
398 	 * OR in our service parameters with other provider (initiator), if any.
399 	 */
400 fill:
401 	fcp_parm = ntohl(spp->spp_params);
402 	fcp_parm &= ~FCP_SPPF_RETRY;
403 	spp->spp_params = htonl(fcp_parm | FCP_SPPF_TARG_FCN);
404 	return FC_SPP_RESP_ACK;
405 
406 not_target:
407 	fcp_parm = ntohl(spp->spp_params);
408 	fcp_parm &= ~FCP_SPPF_TARG_FCN;
409 	spp->spp_params = htonl(fcp_parm);
410 	return 0;
411 }
412 
413 /**
414  * tcm_fcp_prli() - Handle incoming or outgoing PRLI for the FCP target
415  * @rdata: remote port private
416  * @spp_len: service parameter page length
417  * @rspp: received service parameter page (NULL for outgoing PRLI)
418  * @spp: response service parameter page
419  *
420  * Returns spp response code.
421  */
422 static int ft_prli(struct fc_rport_priv *rdata, u32 spp_len,
423 		   const struct fc_els_spp *rspp, struct fc_els_spp *spp)
424 {
425 	int ret;
426 
427 	mutex_lock(&ft_lport_lock);
428 	ret = ft_prli_locked(rdata, spp_len, rspp, spp);
429 	mutex_unlock(&ft_lport_lock);
430 	pr_debug("port_id %x flags %x ret %x\n",
431 	       rdata->ids.port_id, rspp ? rspp->spp_flags : 0, ret);
432 	return ret;
433 }
434 
435 static void ft_sess_rcu_free(struct rcu_head *rcu)
436 {
437 	struct ft_sess *sess = container_of(rcu, struct ft_sess, rcu);
438 
439 	kfree(sess);
440 }
441 
442 static void ft_sess_free(struct kref *kref)
443 {
444 	struct ft_sess *sess = container_of(kref, struct ft_sess, kref);
445 
446 	transport_deregister_session(sess->se_sess);
447 	call_rcu(&sess->rcu, ft_sess_rcu_free);
448 }
449 
450 void ft_sess_put(struct ft_sess *sess)
451 {
452 	int sess_held = atomic_read(&sess->kref.refcount);
453 
454 	BUG_ON(!sess_held);
455 	kref_put(&sess->kref, ft_sess_free);
456 }
457 
458 static void ft_prlo(struct fc_rport_priv *rdata)
459 {
460 	struct ft_sess *sess;
461 	struct ft_tport *tport;
462 
463 	mutex_lock(&ft_lport_lock);
464 	tport = rcu_dereference_protected(rdata->local_port->prov[FC_TYPE_FCP],
465 					  lockdep_is_held(&ft_lport_lock));
466 
467 	if (!tport) {
468 		mutex_unlock(&ft_lport_lock);
469 		return;
470 	}
471 	sess = ft_sess_delete(tport, rdata->ids.port_id);
472 	if (!sess) {
473 		mutex_unlock(&ft_lport_lock);
474 		return;
475 	}
476 	mutex_unlock(&ft_lport_lock);
477 	transport_deregister_session_configfs(sess->se_sess);
478 	ft_sess_put(sess);		/* release from table */
479 	rdata->prli_count--;
480 	/* XXX TBD - clearing actions.  unit attn, see 4.10 */
481 }
482 
483 /*
484  * Handle incoming FCP request.
485  * Caller has verified that the frame is type FCP.
486  */
487 static void ft_recv(struct fc_lport *lport, struct fc_frame *fp)
488 {
489 	struct ft_sess *sess;
490 	u32 sid = fc_frame_sid(fp);
491 
492 	pr_debug("sid %x\n", sid);
493 
494 	sess = ft_sess_get(lport, sid);
495 	if (!sess) {
496 		pr_debug("sid %x sess lookup failed\n", sid);
497 		/* TBD XXX - if FCP_CMND, send PRLO */
498 		fc_frame_free(fp);
499 		return;
500 	}
501 	ft_recv_req(sess, fp);	/* must do ft_sess_put() */
502 }
503 
504 /*
505  * Provider ops for libfc.
506  */
507 struct fc4_prov ft_prov = {
508 	.prli = ft_prli,
509 	.prlo = ft_prlo,
510 	.recv = ft_recv,
511 	.module = THIS_MODULE,
512 };
513