xref: /linux/drivers/target/tcm_fc/tfc_sess.c (revision 4413e16d9d21673bb5048a2e542f1aaa00015c2e) 
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_fabric.h>
44 #include <target/target_core_configfs.h>
45 #include <target/configfs_macros.h>
46 
47 #include "tcm_fc.h"
48 
49 static void ft_sess_delete_all(struct ft_tport *);
50 
51 /*
52  * Lookup or allocate target local port.
53  * Caller holds ft_lport_lock.
54  */
55 static struct ft_tport *ft_tport_create(struct fc_lport *lport)
56 {
57 	struct ft_tpg *tpg;
58 	struct ft_tport *tport;
59 	int i;
60 
61 	tport = rcu_dereference_protected(lport->prov[FC_TYPE_FCP],
62 					  lockdep_is_held(&ft_lport_lock));
63 	if (tport && tport->tpg)
64 		return tport;
65 
66 	tpg = ft_lport_find_tpg(lport);
67 	if (!tpg)
68 		return NULL;
69 
70 	if (tport) {
71 		tport->tpg = tpg;
72 		return tport;
73 	}
74 
75 	tport = kzalloc(sizeof(*tport), GFP_KERNEL);
76 	if (!tport)
77 		return NULL;
78 
79 	tport->lport = lport;
80 	tport->tpg = tpg;
81 	tpg->tport = tport;
82 	for (i = 0; i < FT_SESS_HASH_SIZE; i++)
83 		INIT_HLIST_HEAD(&tport->hash[i]);
84 
85 	rcu_assign_pointer(lport->prov[FC_TYPE_FCP], tport);
86 	return tport;
87 }
88 
89 /*
90  * Delete a target local port.
91  * Caller holds ft_lport_lock.
92  */
93 static void ft_tport_delete(struct ft_tport *tport)
94 {
95 	struct fc_lport *lport;
96 	struct ft_tpg *tpg;
97 
98 	ft_sess_delete_all(tport);
99 	lport = tport->lport;
100 	BUG_ON(tport != lport->prov[FC_TYPE_FCP]);
101 	rcu_assign_pointer(lport->prov[FC_TYPE_FCP], NULL);
102 
103 	tpg = tport->tpg;
104 	if (tpg) {
105 		tpg->tport = NULL;
106 		tport->tpg = NULL;
107 	}
108 	kfree_rcu(tport, rcu);
109 }
110 
111 /*
112  * Add local port.
113  * Called thru fc_lport_iterate().
114  */
115 void ft_lport_add(struct fc_lport *lport, void *arg)
116 {
117 	mutex_lock(&ft_lport_lock);
118 	ft_tport_create(lport);
119 	mutex_unlock(&ft_lport_lock);
120 }
121 
122 /*
123  * Delete local port.
124  * Called thru fc_lport_iterate().
125  */
126 void ft_lport_del(struct fc_lport *lport, void *arg)
127 {
128 	struct ft_tport *tport;
129 
130 	mutex_lock(&ft_lport_lock);
131 	tport = lport->prov[FC_TYPE_FCP];
132 	if (tport)
133 		ft_tport_delete(tport);
134 	mutex_unlock(&ft_lport_lock);
135 }
136 
137 /*
138  * Notification of local port change from libfc.
139  * Create or delete local port and associated tport.
140  */
141 int ft_lport_notify(struct notifier_block *nb, unsigned long event, void *arg)
142 {
143 	struct fc_lport *lport = arg;
144 
145 	switch (event) {
146 	case FC_LPORT_EV_ADD:
147 		ft_lport_add(lport, NULL);
148 		break;
149 	case FC_LPORT_EV_DEL:
150 		ft_lport_del(lport, NULL);
151 		break;
152 	}
153 	return NOTIFY_DONE;
154 }
155 
156 /*
157  * Hash function for FC_IDs.
158  */
159 static u32 ft_sess_hash(u32 port_id)
160 {
161 	return hash_32(port_id, FT_SESS_HASH_BITS);
162 }
163 
164 /*
165  * Find session in local port.
166  * Sessions and hash lists are RCU-protected.
167  * A reference is taken which must be eventually freed.
168  */
169 static struct ft_sess *ft_sess_get(struct fc_lport *lport, u32 port_id)
170 {
171 	struct ft_tport *tport;
172 	struct hlist_head *head;
173 	struct hlist_node *pos;
174 	struct ft_sess *sess;
175 
176 	rcu_read_lock();
177 	tport = rcu_dereference(lport->prov[FC_TYPE_FCP]);
178 	if (!tport)
179 		goto out;
180 
181 	head = &tport->hash[ft_sess_hash(port_id)];
182 	hlist_for_each_entry_rcu(sess, pos, head, hash) {
183 		if (sess->port_id == port_id) {
184 			kref_get(&sess->kref);
185 			rcu_read_unlock();
186 			pr_debug("port_id %x found %p\n", port_id, sess);
187 			return sess;
188 		}
189 	}
190 out:
191 	rcu_read_unlock();
192 	pr_debug("port_id %x not found\n", port_id);
193 	return NULL;
194 }
195 
196 /*
197  * Allocate session and enter it in the hash for the local port.
198  * Caller holds ft_lport_lock.
199  */
200 static struct ft_sess *ft_sess_create(struct ft_tport *tport, u32 port_id,
201 				      struct ft_node_acl *acl)
202 {
203 	struct ft_sess *sess;
204 	struct hlist_head *head;
205 	struct hlist_node *pos;
206 
207 	head = &tport->hash[ft_sess_hash(port_id)];
208 	hlist_for_each_entry_rcu(sess, pos, head, hash)
209 		if (sess->port_id == port_id)
210 			return sess;
211 
212 	sess = kzalloc(sizeof(*sess), GFP_KERNEL);
213 	if (!sess)
214 		return NULL;
215 
216 	sess->se_sess = transport_init_session();
217 	if (IS_ERR(sess->se_sess)) {
218 		kfree(sess);
219 		return NULL;
220 	}
221 	sess->se_sess->se_node_acl = &acl->se_node_acl;
222 	sess->tport = tport;
223 	sess->port_id = port_id;
224 	kref_init(&sess->kref);	/* ref for table entry */
225 	hlist_add_head_rcu(&sess->hash, head);
226 	tport->sess_count++;
227 
228 	pr_debug("port_id %x sess %p\n", port_id, sess);
229 
230 	transport_register_session(&tport->tpg->se_tpg, &acl->se_node_acl,
231 				   sess->se_sess, sess);
232 	return sess;
233 }
234 
235 /*
236  * Unhash the session.
237  * Caller holds ft_lport_lock.
238  */
239 static void ft_sess_unhash(struct ft_sess *sess)
240 {
241 	struct ft_tport *tport = sess->tport;
242 
243 	hlist_del_rcu(&sess->hash);
244 	BUG_ON(!tport->sess_count);
245 	tport->sess_count--;
246 	sess->port_id = -1;
247 	sess->params = 0;
248 }
249 
250 /*
251  * Delete session from hash.
252  * Caller holds ft_lport_lock.
253  */
254 static struct ft_sess *ft_sess_delete(struct ft_tport *tport, u32 port_id)
255 {
256 	struct hlist_head *head;
257 	struct hlist_node *pos;
258 	struct ft_sess *sess;
259 
260 	head = &tport->hash[ft_sess_hash(port_id)];
261 	hlist_for_each_entry_rcu(sess, pos, head, hash) {
262 		if (sess->port_id == port_id) {
263 			ft_sess_unhash(sess);
264 			return sess;
265 		}
266 	}
267 	return NULL;
268 }
269 
270 /*
271  * Delete all sessions from tport.
272  * Caller holds ft_lport_lock.
273  */
274 static void ft_sess_delete_all(struct ft_tport *tport)
275 {
276 	struct hlist_head *head;
277 	struct hlist_node *pos;
278 	struct ft_sess *sess;
279 
280 	for (head = tport->hash;
281 	     head < &tport->hash[FT_SESS_HASH_SIZE]; head++) {
282 		hlist_for_each_entry_rcu(sess, pos, head, hash) {
283 			ft_sess_unhash(sess);
284 			transport_deregister_session_configfs(sess->se_sess);
285 			ft_sess_put(sess);	/* release from table */
286 		}
287 	}
288 }
289 
290 /*
291  * TCM ops for sessions.
292  */
293 
294 /*
295  * Determine whether session is allowed to be shutdown in the current context.
296  * Returns non-zero if the session should be shutdown.
297  */
298 int ft_sess_shutdown(struct se_session *se_sess)
299 {
300 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
301 
302 	pr_debug("port_id %x\n", sess->port_id);
303 	return 1;
304 }
305 
306 /*
307  * Remove session and send PRLO.
308  * This is called when the ACL is being deleted or queue depth is changing.
309  */
310 void ft_sess_close(struct se_session *se_sess)
311 {
312 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
313 	u32 port_id;
314 
315 	mutex_lock(&ft_lport_lock);
316 	port_id = sess->port_id;
317 	if (port_id == -1) {
318 		mutex_unlock(&ft_lport_lock);
319 		return;
320 	}
321 	pr_debug("port_id %x\n", port_id);
322 	ft_sess_unhash(sess);
323 	mutex_unlock(&ft_lport_lock);
324 	transport_deregister_session_configfs(se_sess);
325 	ft_sess_put(sess);
326 	/* XXX Send LOGO or PRLO */
327 	synchronize_rcu();		/* let transport deregister happen */
328 }
329 
330 u32 ft_sess_get_index(struct se_session *se_sess)
331 {
332 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
333 
334 	return sess->port_id;	/* XXX TBD probably not what is needed */
335 }
336 
337 u32 ft_sess_get_port_name(struct se_session *se_sess,
338 			  unsigned char *buf, u32 len)
339 {
340 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
341 
342 	return ft_format_wwn(buf, len, sess->port_name);
343 }
344 
345 /*
346  * libfc ops involving sessions.
347  */
348 
349 static int ft_prli_locked(struct fc_rport_priv *rdata, u32 spp_len,
350 			  const struct fc_els_spp *rspp, struct fc_els_spp *spp)
351 {
352 	struct ft_tport *tport;
353 	struct ft_sess *sess;
354 	struct ft_node_acl *acl;
355 	u32 fcp_parm;
356 
357 	tport = ft_tport_create(rdata->local_port);
358 	if (!tport)
359 		return 0;	/* not a target for this local port */
360 
361 	acl = ft_acl_get(tport->tpg, rdata);
362 	if (!acl)
363 		return 0;
364 
365 	if (!rspp)
366 		goto fill;
367 
368 	if (rspp->spp_flags & (FC_SPP_OPA_VAL | FC_SPP_RPA_VAL))
369 		return FC_SPP_RESP_NO_PA;
370 
371 	/*
372 	 * If both target and initiator bits are off, the SPP is invalid.
373 	 */
374 	fcp_parm = ntohl(rspp->spp_params);
375 	if (!(fcp_parm & (FCP_SPPF_INIT_FCN | FCP_SPPF_TARG_FCN)))
376 		return FC_SPP_RESP_INVL;
377 
378 	/*
379 	 * Create session (image pair) only if requested by
380 	 * EST_IMG_PAIR flag and if the requestor is an initiator.
381 	 */
382 	if (rspp->spp_flags & FC_SPP_EST_IMG_PAIR) {
383 		spp->spp_flags |= FC_SPP_EST_IMG_PAIR;
384 		if (!(fcp_parm & FCP_SPPF_INIT_FCN))
385 			return FC_SPP_RESP_CONF;
386 		sess = ft_sess_create(tport, rdata->ids.port_id, acl);
387 		if (!sess)
388 			return FC_SPP_RESP_RES;
389 		if (!sess->params)
390 			rdata->prli_count++;
391 		sess->params = fcp_parm;
392 		sess->port_name = rdata->ids.port_name;
393 		sess->max_frame = rdata->maxframe_size;
394 
395 		/* XXX TBD - clearing actions.  unit attn, see 4.10 */
396 	}
397 
398 	/*
399 	 * OR in our service parameters with other provider (initiator), if any.
400 	 * TBD XXX - indicate RETRY capability?
401 	 */
402 fill:
403 	fcp_parm = ntohl(spp->spp_params);
404 	spp->spp_params = htonl(fcp_parm | FCP_SPPF_TARG_FCN);
405 	return FC_SPP_RESP_ACK;
406 }
407 
408 /**
409  * tcm_fcp_prli() - Handle incoming or outgoing PRLI for the FCP target
410  * @rdata: remote port private
411  * @spp_len: service parameter page length
412  * @rspp: received service parameter page (NULL for outgoing PRLI)
413  * @spp: response service parameter page
414  *
415  * Returns spp response code.
416  */
417 static int ft_prli(struct fc_rport_priv *rdata, u32 spp_len,
418 		   const struct fc_els_spp *rspp, struct fc_els_spp *spp)
419 {
420 	int ret;
421 
422 	mutex_lock(&ft_lport_lock);
423 	ret = ft_prli_locked(rdata, spp_len, rspp, spp);
424 	mutex_unlock(&ft_lport_lock);
425 	pr_debug("port_id %x flags %x ret %x\n",
426 	       rdata->ids.port_id, rspp ? rspp->spp_flags : 0, ret);
427 	return ret;
428 }
429 
430 static void ft_sess_rcu_free(struct rcu_head *rcu)
431 {
432 	struct ft_sess *sess = container_of(rcu, struct ft_sess, rcu);
433 
434 	transport_deregister_session(sess->se_sess);
435 	kfree(sess);
436 }
437 
438 static void ft_sess_free(struct kref *kref)
439 {
440 	struct ft_sess *sess = container_of(kref, struct ft_sess, kref);
441 
442 	call_rcu(&sess->rcu, ft_sess_rcu_free);
443 }
444 
445 void ft_sess_put(struct ft_sess *sess)
446 {
447 	int sess_held = atomic_read(&sess->kref.refcount);
448 
449 	BUG_ON(!sess_held);
450 	kref_put(&sess->kref, ft_sess_free);
451 }
452 
453 static void ft_prlo(struct fc_rport_priv *rdata)
454 {
455 	struct ft_sess *sess;
456 	struct ft_tport *tport;
457 
458 	mutex_lock(&ft_lport_lock);
459 	tport = rcu_dereference_protected(rdata->local_port->prov[FC_TYPE_FCP],
460 					  lockdep_is_held(&ft_lport_lock));
461 
462 	if (!tport) {
463 		mutex_unlock(&ft_lport_lock);
464 		return;
465 	}
466 	sess = ft_sess_delete(tport, rdata->ids.port_id);
467 	if (!sess) {
468 		mutex_unlock(&ft_lport_lock);
469 		return;
470 	}
471 	mutex_unlock(&ft_lport_lock);
472 	transport_deregister_session_configfs(sess->se_sess);
473 	ft_sess_put(sess);		/* release from table */
474 	rdata->prli_count--;
475 	/* XXX TBD - clearing actions.  unit attn, see 4.10 */
476 }
477 
478 /*
479  * Handle incoming FCP request.
480  * Caller has verified that the frame is type FCP.
481  */
482 static void ft_recv(struct fc_lport *lport, struct fc_frame *fp)
483 {
484 	struct ft_sess *sess;
485 	u32 sid = fc_frame_sid(fp);
486 
487 	pr_debug("sid %x\n", sid);
488 
489 	sess = ft_sess_get(lport, sid);
490 	if (!sess) {
491 		pr_debug("sid %x sess lookup failed\n", sid);
492 		/* TBD XXX - if FCP_CMND, send PRLO */
493 		fc_frame_free(fp);
494 		return;
495 	}
496 	ft_recv_req(sess, fp);	/* must do ft_sess_put() */
497 }
498 
499 /*
500  * Provider ops for libfc.
501  */
502 struct fc4_prov ft_prov = {
503 	.prli = ft_prli,
504 	.prlo = ft_prlo,
505 	.recv = ft_recv,
506 	.module = THIS_MODULE,
507 };
508