xref: /openbmc/linux/drivers/target/tcm_fc/tfc_sess.c (revision bc5aa3a0) 
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 	lport->service_params &= ~FCP_SPPF_TARG_FCN;
95 	BUG_ON(tport != lport->prov[FC_TYPE_FCP]);
96 	RCU_INIT_POINTER(lport->prov[FC_TYPE_FCP], NULL);
97 
98 	tpg = tport->tpg;
99 	if (tpg) {
100 		tpg->tport = NULL;
101 		tport->tpg = NULL;
102 	}
103 	kfree_rcu(tport, rcu);
104 }
105 
106 /*
107  * Add local port.
108  * Called thru fc_lport_iterate().
109  */
110 void ft_lport_add(struct fc_lport *lport, void *arg)
111 {
112 	mutex_lock(&ft_lport_lock);
113 	ft_tport_get(lport);
114 	lport->service_params |= FCP_SPPF_TARG_FCN;
115 	mutex_unlock(&ft_lport_lock);
116 }
117 
118 /*
119  * Delete local port.
120  * Called thru fc_lport_iterate().
121  */
122 void ft_lport_del(struct fc_lport *lport, void *arg)
123 {
124 	struct ft_tport *tport;
125 
126 	mutex_lock(&ft_lport_lock);
127 	tport = lport->prov[FC_TYPE_FCP];
128 	if (tport)
129 		ft_tport_delete(tport);
130 	mutex_unlock(&ft_lport_lock);
131 }
132 
133 /*
134  * Notification of local port change from libfc.
135  * Create or delete local port and associated tport.
136  */
137 int ft_lport_notify(struct notifier_block *nb, unsigned long event, void *arg)
138 {
139 	struct fc_lport *lport = arg;
140 
141 	switch (event) {
142 	case FC_LPORT_EV_ADD:
143 		ft_lport_add(lport, NULL);
144 		break;
145 	case FC_LPORT_EV_DEL:
146 		ft_lport_del(lport, NULL);
147 		break;
148 	}
149 	return NOTIFY_DONE;
150 }
151 
152 /*
153  * Hash function for FC_IDs.
154  */
155 static u32 ft_sess_hash(u32 port_id)
156 {
157 	return hash_32(port_id, FT_SESS_HASH_BITS);
158 }
159 
160 /*
161  * Find session in local port.
162  * Sessions and hash lists are RCU-protected.
163  * A reference is taken which must be eventually freed.
164  */
165 static struct ft_sess *ft_sess_get(struct fc_lport *lport, u32 port_id)
166 {
167 	struct ft_tport *tport;
168 	struct hlist_head *head;
169 	struct ft_sess *sess;
170 
171 	rcu_read_lock();
172 	tport = rcu_dereference(lport->prov[FC_TYPE_FCP]);
173 	if (!tport)
174 		goto out;
175 
176 	head = &tport->hash[ft_sess_hash(port_id)];
177 	hlist_for_each_entry_rcu(sess, head, hash) {
178 		if (sess->port_id == port_id) {
179 			kref_get(&sess->kref);
180 			rcu_read_unlock();
181 			pr_debug("port_id %x found %p\n", port_id, sess);
182 			return sess;
183 		}
184 	}
185 out:
186 	rcu_read_unlock();
187 	pr_debug("port_id %x not found\n", port_id);
188 	return NULL;
189 }
190 
191 static int ft_sess_alloc_cb(struct se_portal_group *se_tpg,
192 			    struct se_session *se_sess, void *p)
193 {
194 	struct ft_sess *sess = p;
195 	struct ft_tport *tport = sess->tport;
196 	struct hlist_head *head = &tport->hash[ft_sess_hash(sess->port_id)];
197 
198 	pr_debug("port_id %x sess %p\n", sess->port_id, sess);
199 	hlist_add_head_rcu(&sess->hash, head);
200 	tport->sess_count++;
201 
202 	return 0;
203 }
204 
205 /*
206  * Allocate session and enter it in the hash for the local port.
207  * Caller holds ft_lport_lock.
208  */
209 static struct ft_sess *ft_sess_create(struct ft_tport *tport, u32 port_id,
210 				      struct fc_rport_priv *rdata)
211 {
212 	struct se_portal_group *se_tpg = &tport->tpg->se_tpg;
213 	struct ft_sess *sess;
214 	struct hlist_head *head;
215 	unsigned char initiatorname[TRANSPORT_IQN_LEN];
216 
217 	ft_format_wwn(&initiatorname[0], TRANSPORT_IQN_LEN, rdata->ids.port_name);
218 
219 	head = &tport->hash[ft_sess_hash(port_id)];
220 	hlist_for_each_entry_rcu(sess, 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 	kref_init(&sess->kref); /* ref for table entry */
229 	sess->tport = tport;
230 	sess->port_id = port_id;
231 
232 	sess->se_sess = target_alloc_session(se_tpg, TCM_FC_DEFAULT_TAGS,
233 					     sizeof(struct ft_cmd),
234 					     TARGET_PROT_NORMAL, &initiatorname[0],
235 					     sess, ft_sess_alloc_cb);
236 	if (IS_ERR(sess->se_sess)) {
237 		kfree(sess);
238 		return NULL;
239 	}
240 	return sess;
241 }
242 
243 /*
244  * Unhash the session.
245  * Caller holds ft_lport_lock.
246  */
247 static void ft_sess_unhash(struct ft_sess *sess)
248 {
249 	struct ft_tport *tport = sess->tport;
250 
251 	hlist_del_rcu(&sess->hash);
252 	BUG_ON(!tport->sess_count);
253 	tport->sess_count--;
254 	sess->port_id = -1;
255 	sess->params = 0;
256 }
257 
258 /*
259  * Delete session from hash.
260  * Caller holds ft_lport_lock.
261  */
262 static struct ft_sess *ft_sess_delete(struct ft_tport *tport, u32 port_id)
263 {
264 	struct hlist_head *head;
265 	struct ft_sess *sess;
266 
267 	head = &tport->hash[ft_sess_hash(port_id)];
268 	hlist_for_each_entry_rcu(sess, head, hash) {
269 		if (sess->port_id == port_id) {
270 			ft_sess_unhash(sess);
271 			return sess;
272 		}
273 	}
274 	return NULL;
275 }
276 
277 static void ft_close_sess(struct ft_sess *sess)
278 {
279 	transport_deregister_session_configfs(sess->se_sess);
280 	target_sess_cmd_list_set_waiting(sess->se_sess);
281 	target_wait_for_sess_cmds(sess->se_sess);
282 	ft_sess_put(sess);
283 }
284 
285 /*
286  * Delete all sessions from tport.
287  * Caller holds ft_lport_lock.
288  */
289 static void ft_sess_delete_all(struct ft_tport *tport)
290 {
291 	struct hlist_head *head;
292 	struct ft_sess *sess;
293 
294 	for (head = tport->hash;
295 	     head < &tport->hash[FT_SESS_HASH_SIZE]; head++) {
296 		hlist_for_each_entry_rcu(sess, head, hash) {
297 			ft_sess_unhash(sess);
298 			ft_close_sess(sess);	/* release from table */
299 		}
300 	}
301 }
302 
303 /*
304  * TCM ops for sessions.
305  */
306 
307 /*
308  * Remove session and send PRLO.
309  * This is called when the ACL is being deleted or queue depth is changing.
310  */
311 void ft_sess_close(struct se_session *se_sess)
312 {
313 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
314 	u32 port_id;
315 
316 	mutex_lock(&ft_lport_lock);
317 	port_id = sess->port_id;
318 	if (port_id == -1) {
319 		mutex_unlock(&ft_lport_lock);
320 		return;
321 	}
322 	pr_debug("port_id %x\n", port_id);
323 	ft_sess_unhash(sess);
324 	mutex_unlock(&ft_lport_lock);
325 	ft_close_sess(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 	u32 fcp_parm;
355 
356 	tport = ft_tport_get(rdata->local_port);
357 	if (!tport)
358 		goto not_target;	/* not a target for this local port */
359 
360 	if (!rspp)
361 		goto fill;
362 
363 	if (rspp->spp_flags & (FC_SPP_OPA_VAL | FC_SPP_RPA_VAL))
364 		return FC_SPP_RESP_NO_PA;
365 
366 	/*
367 	 * If both target and initiator bits are off, the SPP is invalid.
368 	 */
369 	fcp_parm = ntohl(rspp->spp_params);
370 	if (!(fcp_parm & (FCP_SPPF_INIT_FCN | FCP_SPPF_TARG_FCN)))
371 		return FC_SPP_RESP_INVL;
372 
373 	/*
374 	 * Create session (image pair) only if requested by
375 	 * EST_IMG_PAIR flag and if the requestor is an initiator.
376 	 */
377 	if (rspp->spp_flags & FC_SPP_EST_IMG_PAIR) {
378 		spp->spp_flags |= FC_SPP_EST_IMG_PAIR;
379 		if (!(fcp_parm & FCP_SPPF_INIT_FCN))
380 			return FC_SPP_RESP_CONF;
381 		sess = ft_sess_create(tport, rdata->ids.port_id, rdata);
382 		if (!sess)
383 			return FC_SPP_RESP_RES;
384 		if (!sess->params)
385 			rdata->prli_count++;
386 		sess->params = fcp_parm;
387 		sess->port_name = rdata->ids.port_name;
388 		sess->max_frame = rdata->maxframe_size;
389 
390 		/* XXX TBD - clearing actions.  unit attn, see 4.10 */
391 	}
392 
393 	/*
394 	 * OR in our service parameters with other provider (initiator), if any.
395 	 */
396 fill:
397 	fcp_parm = ntohl(spp->spp_params);
398 	fcp_parm &= ~FCP_SPPF_RETRY;
399 	spp->spp_params = htonl(fcp_parm | FCP_SPPF_TARG_FCN);
400 	return FC_SPP_RESP_ACK;
401 
402 not_target:
403 	fcp_parm = ntohl(spp->spp_params);
404 	fcp_parm &= ~FCP_SPPF_TARG_FCN;
405 	spp->spp_params = htonl(fcp_parm);
406 	return 0;
407 }
408 
409 /**
410  * tcm_fcp_prli() - Handle incoming or outgoing PRLI for the FCP target
411  * @rdata: remote port private
412  * @spp_len: service parameter page length
413  * @rspp: received service parameter page (NULL for outgoing PRLI)
414  * @spp: response service parameter page
415  *
416  * Returns spp response code.
417  */
418 static int ft_prli(struct fc_rport_priv *rdata, u32 spp_len,
419 		   const struct fc_els_spp *rspp, struct fc_els_spp *spp)
420 {
421 	int ret;
422 
423 	mutex_lock(&ft_lport_lock);
424 	ret = ft_prli_locked(rdata, spp_len, rspp, spp);
425 	mutex_unlock(&ft_lport_lock);
426 	pr_debug("port_id %x flags %x ret %x\n",
427 	       rdata->ids.port_id, rspp ? rspp->spp_flags : 0, ret);
428 	return ret;
429 }
430 
431 static void ft_sess_free(struct kref *kref)
432 {
433 	struct ft_sess *sess = container_of(kref, struct ft_sess, kref);
434 
435 	transport_deregister_session(sess->se_sess);
436 	kfree_rcu(sess, rcu);
437 }
438 
439 void ft_sess_put(struct ft_sess *sess)
440 {
441 	int sess_held = atomic_read(&sess->kref.refcount);
442 
443 	BUG_ON(!sess_held);
444 	kref_put(&sess->kref, ft_sess_free);
445 }
446 
447 static void ft_prlo(struct fc_rport_priv *rdata)
448 {
449 	struct ft_sess *sess;
450 	struct ft_tport *tport;
451 
452 	mutex_lock(&ft_lport_lock);
453 	tport = rcu_dereference_protected(rdata->local_port->prov[FC_TYPE_FCP],
454 					  lockdep_is_held(&ft_lport_lock));
455 
456 	if (!tport) {
457 		mutex_unlock(&ft_lport_lock);
458 		return;
459 	}
460 	sess = ft_sess_delete(tport, rdata->ids.port_id);
461 	if (!sess) {
462 		mutex_unlock(&ft_lport_lock);
463 		return;
464 	}
465 	mutex_unlock(&ft_lport_lock);
466 	ft_close_sess(sess);		/* release from table */
467 	rdata->prli_count--;
468 	/* XXX TBD - clearing actions.  unit attn, see 4.10 */
469 }
470 
471 /*
472  * Handle incoming FCP request.
473  * Caller has verified that the frame is type FCP.
474  */
475 static void ft_recv(struct fc_lport *lport, struct fc_frame *fp)
476 {
477 	struct ft_sess *sess;
478 	u32 sid = fc_frame_sid(fp);
479 
480 	pr_debug("sid %x\n", sid);
481 
482 	sess = ft_sess_get(lport, sid);
483 	if (!sess) {
484 		pr_debug("sid %x sess lookup failed\n", sid);
485 		/* TBD XXX - if FCP_CMND, send PRLO */
486 		fc_frame_free(fp);
487 		return;
488 	}
489 	ft_recv_req(sess, fp);	/* must do ft_sess_put() */
490 }
491 
492 /*
493  * Provider ops for libfc.
494  */
495 struct fc4_prov ft_prov = {
496 	.prli = ft_prli,
497 	.prlo = ft_prlo,
498 	.recv = ft_recv,
499 	.module = THIS_MODULE,
500 };
501