xref: /openbmc/linux/drivers/target/tcm_fc/tfc_sess.c (revision 78700c0a) 
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/libfc.h>
36 
37 #include <target/target_core_base.h>
38 #include <target/target_core_fabric.h>
39 
40 #include "tcm_fc.h"
41 
42 static void ft_sess_delete_all(struct ft_tport *);
43 
44 /*
45  * Lookup or allocate target local port.
46  * Caller holds ft_lport_lock.
47  */
48 static struct ft_tport *ft_tport_get(struct fc_lport *lport)
49 {
50 	struct ft_tpg *tpg;
51 	struct ft_tport *tport;
52 	int i;
53 
54 	tport = rcu_dereference_protected(lport->prov[FC_TYPE_FCP],
55 					  lockdep_is_held(&ft_lport_lock));
56 	if (tport && tport->tpg)
57 		return tport;
58 
59 	tpg = ft_lport_find_tpg(lport);
60 	if (!tpg)
61 		return NULL;
62 
63 	if (tport) {
64 		tport->tpg = tpg;
65 		tpg->tport = tport;
66 		return tport;
67 	}
68 
69 	tport = kzalloc(sizeof(*tport), GFP_KERNEL);
70 	if (!tport)
71 		return NULL;
72 
73 	tport->lport = lport;
74 	tport->tpg = tpg;
75 	tpg->tport = tport;
76 	for (i = 0; i < FT_SESS_HASH_SIZE; i++)
77 		INIT_HLIST_HEAD(&tport->hash[i]);
78 
79 	rcu_assign_pointer(lport->prov[FC_TYPE_FCP], tport);
80 	return tport;
81 }
82 
83 /*
84  * Delete a target local port.
85  * Caller holds ft_lport_lock.
86  */
87 static void ft_tport_delete(struct ft_tport *tport)
88 {
89 	struct fc_lport *lport;
90 	struct ft_tpg *tpg;
91 
92 	ft_sess_delete_all(tport);
93 	lport = tport->lport;
94 	BUG_ON(tport != lport->prov[FC_TYPE_FCP]);
95 	RCU_INIT_POINTER(lport->prov[FC_TYPE_FCP], NULL);
96 
97 	tpg = tport->tpg;
98 	if (tpg) {
99 		tpg->tport = NULL;
100 		tport->tpg = NULL;
101 	}
102 	kfree_rcu(tport, rcu);
103 }
104 
105 /*
106  * Add local port.
107  * Called thru fc_lport_iterate().
108  */
109 void ft_lport_add(struct fc_lport *lport, void *arg)
110 {
111 	mutex_lock(&ft_lport_lock);
112 	ft_tport_get(lport);
113 	mutex_unlock(&ft_lport_lock);
114 }
115 
116 /*
117  * Delete local port.
118  * Called thru fc_lport_iterate().
119  */
120 void ft_lport_del(struct fc_lport *lport, void *arg)
121 {
122 	struct ft_tport *tport;
123 
124 	mutex_lock(&ft_lport_lock);
125 	tport = lport->prov[FC_TYPE_FCP];
126 	if (tport)
127 		ft_tport_delete(tport);
128 	mutex_unlock(&ft_lport_lock);
129 }
130 
131 /*
132  * Notification of local port change from libfc.
133  * Create or delete local port and associated tport.
134  */
135 int ft_lport_notify(struct notifier_block *nb, unsigned long event, void *arg)
136 {
137 	struct fc_lport *lport = arg;
138 
139 	switch (event) {
140 	case FC_LPORT_EV_ADD:
141 		ft_lport_add(lport, NULL);
142 		break;
143 	case FC_LPORT_EV_DEL:
144 		ft_lport_del(lport, NULL);
145 		break;
146 	}
147 	return NOTIFY_DONE;
148 }
149 
150 /*
151  * Hash function for FC_IDs.
152  */
153 static u32 ft_sess_hash(u32 port_id)
154 {
155 	return hash_32(port_id, FT_SESS_HASH_BITS);
156 }
157 
158 /*
159  * Find session in local port.
160  * Sessions and hash lists are RCU-protected.
161  * A reference is taken which must be eventually freed.
162  */
163 static struct ft_sess *ft_sess_get(struct fc_lport *lport, u32 port_id)
164 {
165 	struct ft_tport *tport;
166 	struct hlist_head *head;
167 	struct ft_sess *sess;
168 
169 	rcu_read_lock();
170 	tport = rcu_dereference(lport->prov[FC_TYPE_FCP]);
171 	if (!tport)
172 		goto out;
173 
174 	head = &tport->hash[ft_sess_hash(port_id)];
175 	hlist_for_each_entry_rcu(sess, head, hash) {
176 		if (sess->port_id == port_id) {
177 			kref_get(&sess->kref);
178 			rcu_read_unlock();
179 			pr_debug("port_id %x found %p\n", port_id, sess);
180 			return sess;
181 		}
182 	}
183 out:
184 	rcu_read_unlock();
185 	pr_debug("port_id %x not found\n", port_id);
186 	return NULL;
187 }
188 
189 static int ft_sess_alloc_cb(struct se_portal_group *se_tpg,
190 			    struct se_session *se_sess, void *p)
191 {
192 	struct ft_sess *sess = p;
193 	struct ft_tport *tport = sess->tport;
194 	struct hlist_head *head = &tport->hash[ft_sess_hash(sess->port_id)];
195 
196 	pr_debug("port_id %x sess %p\n", sess->port_id, sess);
197 	hlist_add_head_rcu(&sess->hash, head);
198 	tport->sess_count++;
199 
200 	return 0;
201 }
202 
203 /*
204  * Allocate session and enter it in the hash for the local port.
205  * Caller holds ft_lport_lock.
206  */
207 static struct ft_sess *ft_sess_create(struct ft_tport *tport, u32 port_id,
208 				      struct fc_rport_priv *rdata)
209 {
210 	struct se_portal_group *se_tpg = &tport->tpg->se_tpg;
211 	struct ft_sess *sess;
212 	struct hlist_head *head;
213 	unsigned char initiatorname[TRANSPORT_IQN_LEN];
214 
215 	ft_format_wwn(&initiatorname[0], TRANSPORT_IQN_LEN, rdata->ids.port_name);
216 
217 	head = &tport->hash[ft_sess_hash(port_id)];
218 	hlist_for_each_entry_rcu(sess, head, hash)
219 		if (sess->port_id == port_id)
220 			return sess;
221 
222 	sess = kzalloc(sizeof(*sess), GFP_KERNEL);
223 	if (!sess)
224 		return NULL;
225 
226 	kref_init(&sess->kref); /* ref for table entry */
227 	sess->tport = tport;
228 	sess->port_id = port_id;
229 
230 	sess->se_sess = target_alloc_session(se_tpg, TCM_FC_DEFAULT_TAGS,
231 					     sizeof(struct ft_cmd),
232 					     TARGET_PROT_NORMAL, &initiatorname[0],
233 					     sess, ft_sess_alloc_cb);
234 	if (IS_ERR(sess->se_sess)) {
235 		kfree(sess);
236 		return NULL;
237 	}
238 	return sess;
239 }
240 
241 /*
242  * Unhash the session.
243  * Caller holds ft_lport_lock.
244  */
245 static void ft_sess_unhash(struct ft_sess *sess)
246 {
247 	struct ft_tport *tport = sess->tport;
248 
249 	hlist_del_rcu(&sess->hash);
250 	BUG_ON(!tport->sess_count);
251 	tport->sess_count--;
252 	sess->port_id = -1;
253 	sess->params = 0;
254 }
255 
256 /*
257  * Delete session from hash.
258  * Caller holds ft_lport_lock.
259  */
260 static struct ft_sess *ft_sess_delete(struct ft_tport *tport, u32 port_id)
261 {
262 	struct hlist_head *head;
263 	struct ft_sess *sess;
264 
265 	head = &tport->hash[ft_sess_hash(port_id)];
266 	hlist_for_each_entry_rcu(sess, head, hash) {
267 		if (sess->port_id == port_id) {
268 			ft_sess_unhash(sess);
269 			return sess;
270 		}
271 	}
272 	return NULL;
273 }
274 
275 static void ft_close_sess(struct ft_sess *sess)
276 {
277 	transport_deregister_session_configfs(sess->se_sess);
278 	target_sess_cmd_list_set_waiting(sess->se_sess);
279 	target_wait_for_sess_cmds(sess->se_sess);
280 	ft_sess_put(sess);
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 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, head, hash) {
295 			ft_sess_unhash(sess);
296 			ft_close_sess(sess);	/* release from table */
297 		}
298 	}
299 }
300 
301 /*
302  * TCM ops for sessions.
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 	ft_close_sess(sess);
324 	/* XXX Send LOGO or PRLO */
325 	synchronize_rcu();		/* let transport deregister happen */
326 }
327 
328 u32 ft_sess_get_index(struct se_session *se_sess)
329 {
330 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
331 
332 	return sess->port_id;	/* XXX TBD probably not what is needed */
333 }
334 
335 u32 ft_sess_get_port_name(struct se_session *se_sess,
336 			  unsigned char *buf, u32 len)
337 {
338 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
339 
340 	return ft_format_wwn(buf, len, sess->port_name);
341 }
342 
343 /*
344  * libfc ops involving sessions.
345  */
346 
347 static int ft_prli_locked(struct fc_rport_priv *rdata, u32 spp_len,
348 			  const struct fc_els_spp *rspp, struct fc_els_spp *spp)
349 {
350 	struct ft_tport *tport;
351 	struct ft_sess *sess;
352 	u32 fcp_parm;
353 
354 	tport = ft_tport_get(rdata->local_port);
355 	if (!tport)
356 		goto not_target;	/* not a target for this local port */
357 
358 	if (!rspp)
359 		goto fill;
360 
361 	if (rspp->spp_flags & (FC_SPP_OPA_VAL | FC_SPP_RPA_VAL))
362 		return FC_SPP_RESP_NO_PA;
363 
364 	/*
365 	 * If both target and initiator bits are off, the SPP is invalid.
366 	 */
367 	fcp_parm = ntohl(rspp->spp_params);
368 	if (!(fcp_parm & (FCP_SPPF_INIT_FCN | FCP_SPPF_TARG_FCN)))
369 		return FC_SPP_RESP_INVL;
370 
371 	/*
372 	 * Create session (image pair) only if requested by
373 	 * EST_IMG_PAIR flag and if the requestor is an initiator.
374 	 */
375 	if (rspp->spp_flags & FC_SPP_EST_IMG_PAIR) {
376 		spp->spp_flags |= FC_SPP_EST_IMG_PAIR;
377 		if (!(fcp_parm & FCP_SPPF_INIT_FCN))
378 			return FC_SPP_RESP_CONF;
379 		sess = ft_sess_create(tport, rdata->ids.port_id, rdata);
380 		if (!sess)
381 			return FC_SPP_RESP_RES;
382 		if (!sess->params)
383 			rdata->prli_count++;
384 		sess->params = fcp_parm;
385 		sess->port_name = rdata->ids.port_name;
386 		sess->max_frame = rdata->maxframe_size;
387 
388 		/* XXX TBD - clearing actions.  unit attn, see 4.10 */
389 	}
390 
391 	/*
392 	 * OR in our service parameters with other provider (initiator), if any.
393 	 */
394 fill:
395 	fcp_parm = ntohl(spp->spp_params);
396 	fcp_parm &= ~FCP_SPPF_RETRY;
397 	spp->spp_params = htonl(fcp_parm | FCP_SPPF_TARG_FCN);
398 	return FC_SPP_RESP_ACK;
399 
400 not_target:
401 	fcp_parm = ntohl(spp->spp_params);
402 	fcp_parm &= ~FCP_SPPF_TARG_FCN;
403 	spp->spp_params = htonl(fcp_parm);
404 	return 0;
405 }
406 
407 /**
408  * tcm_fcp_prli() - Handle incoming or outgoing PRLI for the FCP target
409  * @rdata: remote port private
410  * @spp_len: service parameter page length
411  * @rspp: received service parameter page (NULL for outgoing PRLI)
412  * @spp: response service parameter page
413  *
414  * Returns spp response code.
415  */
416 static int ft_prli(struct fc_rport_priv *rdata, u32 spp_len,
417 		   const struct fc_els_spp *rspp, struct fc_els_spp *spp)
418 {
419 	int ret;
420 
421 	mutex_lock(&ft_lport_lock);
422 	ret = ft_prli_locked(rdata, spp_len, rspp, spp);
423 	mutex_unlock(&ft_lport_lock);
424 	pr_debug("port_id %x flags %x ret %x\n",
425 	       rdata->ids.port_id, rspp ? rspp->spp_flags : 0, ret);
426 	return ret;
427 }
428 
429 static void ft_sess_free(struct kref *kref)
430 {
431 	struct ft_sess *sess = container_of(kref, struct ft_sess, kref);
432 
433 	transport_deregister_session(sess->se_sess);
434 	kfree_rcu(sess, rcu);
435 }
436 
437 void ft_sess_put(struct ft_sess *sess)
438 {
439 	int sess_held = atomic_read(&sess->kref.refcount);
440 
441 	BUG_ON(!sess_held);
442 	kref_put(&sess->kref, ft_sess_free);
443 }
444 
445 static void ft_prlo(struct fc_rport_priv *rdata)
446 {
447 	struct ft_sess *sess;
448 	struct ft_tport *tport;
449 
450 	mutex_lock(&ft_lport_lock);
451 	tport = rcu_dereference_protected(rdata->local_port->prov[FC_TYPE_FCP],
452 					  lockdep_is_held(&ft_lport_lock));
453 
454 	if (!tport) {
455 		mutex_unlock(&ft_lport_lock);
456 		return;
457 	}
458 	sess = ft_sess_delete(tport, rdata->ids.port_id);
459 	if (!sess) {
460 		mutex_unlock(&ft_lport_lock);
461 		return;
462 	}
463 	mutex_unlock(&ft_lport_lock);
464 	ft_close_sess(sess);		/* release from table */
465 	rdata->prli_count--;
466 	/* XXX TBD - clearing actions.  unit attn, see 4.10 */
467 }
468 
469 /*
470  * Handle incoming FCP request.
471  * Caller has verified that the frame is type FCP.
472  */
473 static void ft_recv(struct fc_lport *lport, struct fc_frame *fp)
474 {
475 	struct ft_sess *sess;
476 	u32 sid = fc_frame_sid(fp);
477 
478 	pr_debug("sid %x\n", sid);
479 
480 	sess = ft_sess_get(lport, sid);
481 	if (!sess) {
482 		pr_debug("sid %x sess lookup failed\n", sid);
483 		/* TBD XXX - if FCP_CMND, send PRLO */
484 		fc_frame_free(fp);
485 		return;
486 	}
487 	ft_recv_req(sess, fp);	/* must do ft_sess_put() */
488 }
489 
490 /*
491  * Provider ops for libfc.
492  */
493 struct fc4_prov ft_prov = {
494 	.prli = ft_prli,
495 	.prlo = ft_prlo,
496 	.recv = ft_recv,
497 	.module = THIS_MODULE,
498 };
499