xref: /openbmc/linux/drivers/target/tcm_fc/tfc_sess.c (revision e23feb16) 
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 ft_sess *sess;
173 
174 	rcu_read_lock();
175 	tport = rcu_dereference(lport->prov[FC_TYPE_FCP]);
176 	if (!tport)
177 		goto out;
178 
179 	head = &tport->hash[ft_sess_hash(port_id)];
180 	hlist_for_each_entry_rcu(sess, head, hash) {
181 		if (sess->port_id == port_id) {
182 			kref_get(&sess->kref);
183 			rcu_read_unlock();
184 			pr_debug("port_id %x found %p\n", port_id, sess);
185 			return sess;
186 		}
187 	}
188 out:
189 	rcu_read_unlock();
190 	pr_debug("port_id %x not found\n", port_id);
191 	return NULL;
192 }
193 
194 /*
195  * Allocate session and enter it in the hash for the local port.
196  * Caller holds ft_lport_lock.
197  */
198 static struct ft_sess *ft_sess_create(struct ft_tport *tport, u32 port_id,
199 				      struct ft_node_acl *acl)
200 {
201 	struct ft_sess *sess;
202 	struct hlist_head *head;
203 
204 	head = &tport->hash[ft_sess_hash(port_id)];
205 	hlist_for_each_entry_rcu(sess, head, hash)
206 		if (sess->port_id == port_id)
207 			return sess;
208 
209 	sess = kzalloc(sizeof(*sess), GFP_KERNEL);
210 	if (!sess)
211 		return NULL;
212 
213 	sess->se_sess = transport_init_session();
214 	if (IS_ERR(sess->se_sess)) {
215 		kfree(sess);
216 		return NULL;
217 	}
218 	sess->se_sess->se_node_acl = &acl->se_node_acl;
219 	sess->tport = tport;
220 	sess->port_id = port_id;
221 	kref_init(&sess->kref);	/* ref for table entry */
222 	hlist_add_head_rcu(&sess->hash, head);
223 	tport->sess_count++;
224 
225 	pr_debug("port_id %x sess %p\n", port_id, sess);
226 
227 	transport_register_session(&tport->tpg->se_tpg, &acl->se_node_acl,
228 				   sess->se_sess, sess);
229 	return sess;
230 }
231 
232 /*
233  * Unhash the session.
234  * Caller holds ft_lport_lock.
235  */
236 static void ft_sess_unhash(struct ft_sess *sess)
237 {
238 	struct ft_tport *tport = sess->tport;
239 
240 	hlist_del_rcu(&sess->hash);
241 	BUG_ON(!tport->sess_count);
242 	tport->sess_count--;
243 	sess->port_id = -1;
244 	sess->params = 0;
245 }
246 
247 /*
248  * Delete session from hash.
249  * Caller holds ft_lport_lock.
250  */
251 static struct ft_sess *ft_sess_delete(struct ft_tport *tport, u32 port_id)
252 {
253 	struct hlist_head *head;
254 	struct ft_sess *sess;
255 
256 	head = &tport->hash[ft_sess_hash(port_id)];
257 	hlist_for_each_entry_rcu(sess, head, hash) {
258 		if (sess->port_id == port_id) {
259 			ft_sess_unhash(sess);
260 			return sess;
261 		}
262 	}
263 	return NULL;
264 }
265 
266 /*
267  * Delete all sessions from tport.
268  * Caller holds ft_lport_lock.
269  */
270 static void ft_sess_delete_all(struct ft_tport *tport)
271 {
272 	struct hlist_head *head;
273 	struct ft_sess *sess;
274 
275 	for (head = tport->hash;
276 	     head < &tport->hash[FT_SESS_HASH_SIZE]; head++) {
277 		hlist_for_each_entry_rcu(sess, head, hash) {
278 			ft_sess_unhash(sess);
279 			transport_deregister_session_configfs(sess->se_sess);
280 			ft_sess_put(sess);	/* release from table */
281 		}
282 	}
283 }
284 
285 /*
286  * TCM ops for sessions.
287  */
288 
289 /*
290  * Determine whether session is allowed to be shutdown in the current context.
291  * Returns non-zero if the session should be shutdown.
292  */
293 int ft_sess_shutdown(struct se_session *se_sess)
294 {
295 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
296 
297 	pr_debug("port_id %x\n", sess->port_id);
298 	return 1;
299 }
300 
301 /*
302  * Remove session and send PRLO.
303  * This is called when the ACL is being deleted or queue depth is changing.
304  */
305 void ft_sess_close(struct se_session *se_sess)
306 {
307 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
308 	u32 port_id;
309 
310 	mutex_lock(&ft_lport_lock);
311 	port_id = sess->port_id;
312 	if (port_id == -1) {
313 		mutex_unlock(&ft_lport_lock);
314 		return;
315 	}
316 	pr_debug("port_id %x\n", port_id);
317 	ft_sess_unhash(sess);
318 	mutex_unlock(&ft_lport_lock);
319 	transport_deregister_session_configfs(se_sess);
320 	ft_sess_put(sess);
321 	/* XXX Send LOGO or PRLO */
322 	synchronize_rcu();		/* let transport deregister happen */
323 }
324 
325 u32 ft_sess_get_index(struct se_session *se_sess)
326 {
327 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
328 
329 	return sess->port_id;	/* XXX TBD probably not what is needed */
330 }
331 
332 u32 ft_sess_get_port_name(struct se_session *se_sess,
333 			  unsigned char *buf, u32 len)
334 {
335 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
336 
337 	return ft_format_wwn(buf, len, sess->port_name);
338 }
339 
340 /*
341  * libfc ops involving sessions.
342  */
343 
344 static int ft_prli_locked(struct fc_rport_priv *rdata, u32 spp_len,
345 			  const struct fc_els_spp *rspp, struct fc_els_spp *spp)
346 {
347 	struct ft_tport *tport;
348 	struct ft_sess *sess;
349 	struct ft_node_acl *acl;
350 	u32 fcp_parm;
351 
352 	tport = ft_tport_create(rdata->local_port);
353 	if (!tport)
354 		goto not_target;	/* not a target for this local port */
355 
356 	acl = ft_acl_get(tport->tpg, rdata);
357 	if (!acl)
358 		goto not_target;	/* no target for this remote */
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, acl);
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 	transport_deregister_session_configfs(sess->se_sess);
467 	ft_sess_put(sess);		/* release from table */
468 	rdata->prli_count--;
469 	/* XXX TBD - clearing actions.  unit attn, see 4.10 */
470 }
471 
472 /*
473  * Handle incoming FCP request.
474  * Caller has verified that the frame is type FCP.
475  */
476 static void ft_recv(struct fc_lport *lport, struct fc_frame *fp)
477 {
478 	struct ft_sess *sess;
479 	u32 sid = fc_frame_sid(fp);
480 
481 	pr_debug("sid %x\n", sid);
482 
483 	sess = ft_sess_get(lport, sid);
484 	if (!sess) {
485 		pr_debug("sid %x sess lookup failed\n", sid);
486 		/* TBD XXX - if FCP_CMND, send PRLO */
487 		fc_frame_free(fp);
488 		return;
489 	}
490 	ft_recv_req(sess, fp);	/* must do ft_sess_put() */
491 }
492 
493 /*
494  * Provider ops for libfc.
495  */
496 struct fc4_prov ft_prov = {
497 	.prli = ft_prli,
498 	.prlo = ft_prlo,
499 	.recv = ft_recv,
500 	.module = THIS_MODULE,
501 };
502