xref: /linux/drivers/target/tcm_fc/tfc_sess.c (revision c4ee0af3fa0dc65f690fc908f02b8355f9576ea0) 
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_tags(TCM_FC_DEFAULT_TAGS,
214 						    sizeof(struct ft_cmd));
215 	if (IS_ERR(sess->se_sess)) {
216 		kfree(sess);
217 		return NULL;
218 	}
219 	sess->se_sess->se_node_acl = &acl->se_node_acl;
220 	sess->tport = tport;
221 	sess->port_id = port_id;
222 	kref_init(&sess->kref);	/* ref for table entry */
223 	hlist_add_head_rcu(&sess->hash, head);
224 	tport->sess_count++;
225 
226 	pr_debug("port_id %x sess %p\n", port_id, sess);
227 
228 	transport_register_session(&tport->tpg->se_tpg, &acl->se_node_acl,
229 				   sess->se_sess, sess);
230 	return sess;
231 }
232 
233 /*
234  * Unhash the session.
235  * Caller holds ft_lport_lock.
236  */
237 static void ft_sess_unhash(struct ft_sess *sess)
238 {
239 	struct ft_tport *tport = sess->tport;
240 
241 	hlist_del_rcu(&sess->hash);
242 	BUG_ON(!tport->sess_count);
243 	tport->sess_count--;
244 	sess->port_id = -1;
245 	sess->params = 0;
246 }
247 
248 /*
249  * Delete session from hash.
250  * Caller holds ft_lport_lock.
251  */
252 static struct ft_sess *ft_sess_delete(struct ft_tport *tport, u32 port_id)
253 {
254 	struct hlist_head *head;
255 	struct ft_sess *sess;
256 
257 	head = &tport->hash[ft_sess_hash(port_id)];
258 	hlist_for_each_entry_rcu(sess, head, hash) {
259 		if (sess->port_id == port_id) {
260 			ft_sess_unhash(sess);
261 			return sess;
262 		}
263 	}
264 	return NULL;
265 }
266 
267 /*
268  * Delete all sessions from tport.
269  * Caller holds ft_lport_lock.
270  */
271 static void ft_sess_delete_all(struct ft_tport *tport)
272 {
273 	struct hlist_head *head;
274 	struct ft_sess *sess;
275 
276 	for (head = tport->hash;
277 	     head < &tport->hash[FT_SESS_HASH_SIZE]; head++) {
278 		hlist_for_each_entry_rcu(sess, head, hash) {
279 			ft_sess_unhash(sess);
280 			transport_deregister_session_configfs(sess->se_sess);
281 			ft_sess_put(sess);	/* release from table */
282 		}
283 	}
284 }
285 
286 /*
287  * TCM ops for sessions.
288  */
289 
290 /*
291  * Determine whether session is allowed to be shutdown in the current context.
292  * Returns non-zero if the session should be shutdown.
293  */
294 int ft_sess_shutdown(struct se_session *se_sess)
295 {
296 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
297 
298 	pr_debug("port_id %x\n", sess->port_id);
299 	return 1;
300 }
301 
302 /*
303  * Remove session and send PRLO.
304  * This is called when the ACL is being deleted or queue depth is changing.
305  */
306 void ft_sess_close(struct se_session *se_sess)
307 {
308 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
309 	u32 port_id;
310 
311 	mutex_lock(&ft_lport_lock);
312 	port_id = sess->port_id;
313 	if (port_id == -1) {
314 		mutex_unlock(&ft_lport_lock);
315 		return;
316 	}
317 	pr_debug("port_id %x\n", port_id);
318 	ft_sess_unhash(sess);
319 	mutex_unlock(&ft_lport_lock);
320 	transport_deregister_session_configfs(se_sess);
321 	ft_sess_put(sess);
322 	/* XXX Send LOGO or PRLO */
323 	synchronize_rcu();		/* let transport deregister happen */
324 }
325 
326 u32 ft_sess_get_index(struct se_session *se_sess)
327 {
328 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
329 
330 	return sess->port_id;	/* XXX TBD probably not what is needed */
331 }
332 
333 u32 ft_sess_get_port_name(struct se_session *se_sess,
334 			  unsigned char *buf, u32 len)
335 {
336 	struct ft_sess *sess = se_sess->fabric_sess_ptr;
337 
338 	return ft_format_wwn(buf, len, sess->port_name);
339 }
340 
341 /*
342  * libfc ops involving sessions.
343  */
344 
345 static int ft_prli_locked(struct fc_rport_priv *rdata, u32 spp_len,
346 			  const struct fc_els_spp *rspp, struct fc_els_spp *spp)
347 {
348 	struct ft_tport *tport;
349 	struct ft_sess *sess;
350 	struct ft_node_acl *acl;
351 	u32 fcp_parm;
352 
353 	tport = ft_tport_create(rdata->local_port);
354 	if (!tport)
355 		goto not_target;	/* not a target for this local port */
356 
357 	acl = ft_acl_get(tport->tpg, rdata);
358 	if (!acl)
359 		goto not_target;	/* no target for this remote */
360 
361 	if (!rspp)
362 		goto fill;
363 
364 	if (rspp->spp_flags & (FC_SPP_OPA_VAL | FC_SPP_RPA_VAL))
365 		return FC_SPP_RESP_NO_PA;
366 
367 	/*
368 	 * If both target and initiator bits are off, the SPP is invalid.
369 	 */
370 	fcp_parm = ntohl(rspp->spp_params);
371 	if (!(fcp_parm & (FCP_SPPF_INIT_FCN | FCP_SPPF_TARG_FCN)))
372 		return FC_SPP_RESP_INVL;
373 
374 	/*
375 	 * Create session (image pair) only if requested by
376 	 * EST_IMG_PAIR flag and if the requestor is an initiator.
377 	 */
378 	if (rspp->spp_flags & FC_SPP_EST_IMG_PAIR) {
379 		spp->spp_flags |= FC_SPP_EST_IMG_PAIR;
380 		if (!(fcp_parm & FCP_SPPF_INIT_FCN))
381 			return FC_SPP_RESP_CONF;
382 		sess = ft_sess_create(tport, rdata->ids.port_id, acl);
383 		if (!sess)
384 			return FC_SPP_RESP_RES;
385 		if (!sess->params)
386 			rdata->prli_count++;
387 		sess->params = fcp_parm;
388 		sess->port_name = rdata->ids.port_name;
389 		sess->max_frame = rdata->maxframe_size;
390 
391 		/* XXX TBD - clearing actions.  unit attn, see 4.10 */
392 	}
393 
394 	/*
395 	 * OR in our service parameters with other provider (initiator), if any.
396 	 */
397 fill:
398 	fcp_parm = ntohl(spp->spp_params);
399 	fcp_parm &= ~FCP_SPPF_RETRY;
400 	spp->spp_params = htonl(fcp_parm | FCP_SPPF_TARG_FCN);
401 	return FC_SPP_RESP_ACK;
402 
403 not_target:
404 	fcp_parm = ntohl(spp->spp_params);
405 	fcp_parm &= ~FCP_SPPF_TARG_FCN;
406 	spp->spp_params = htonl(fcp_parm);
407 	return 0;
408 }
409 
410 /**
411  * tcm_fcp_prli() - Handle incoming or outgoing PRLI for the FCP target
412  * @rdata: remote port private
413  * @spp_len: service parameter page length
414  * @rspp: received service parameter page (NULL for outgoing PRLI)
415  * @spp: response service parameter page
416  *
417  * Returns spp response code.
418  */
419 static int ft_prli(struct fc_rport_priv *rdata, u32 spp_len,
420 		   const struct fc_els_spp *rspp, struct fc_els_spp *spp)
421 {
422 	int ret;
423 
424 	mutex_lock(&ft_lport_lock);
425 	ret = ft_prli_locked(rdata, spp_len, rspp, spp);
426 	mutex_unlock(&ft_lport_lock);
427 	pr_debug("port_id %x flags %x ret %x\n",
428 	       rdata->ids.port_id, rspp ? rspp->spp_flags : 0, ret);
429 	return ret;
430 }
431 
432 static void ft_sess_free(struct kref *kref)
433 {
434 	struct ft_sess *sess = container_of(kref, struct ft_sess, kref);
435 
436 	transport_deregister_session(sess->se_sess);
437 	kfree_rcu(sess, rcu);
438 }
439 
440 void ft_sess_put(struct ft_sess *sess)
441 {
442 	int sess_held = atomic_read(&sess->kref.refcount);
443 
444 	BUG_ON(!sess_held);
445 	kref_put(&sess->kref, ft_sess_free);
446 }
447 
448 static void ft_prlo(struct fc_rport_priv *rdata)
449 {
450 	struct ft_sess *sess;
451 	struct ft_tport *tport;
452 
453 	mutex_lock(&ft_lport_lock);
454 	tport = rcu_dereference_protected(rdata->local_port->prov[FC_TYPE_FCP],
455 					  lockdep_is_held(&ft_lport_lock));
456 
457 	if (!tport) {
458 		mutex_unlock(&ft_lport_lock);
459 		return;
460 	}
461 	sess = ft_sess_delete(tport, rdata->ids.port_id);
462 	if (!sess) {
463 		mutex_unlock(&ft_lport_lock);
464 		return;
465 	}
466 	mutex_unlock(&ft_lport_lock);
467 	transport_deregister_session_configfs(sess->se_sess);
468 	ft_sess_put(sess);		/* release from table */
469 	rdata->prli_count--;
470 	/* XXX TBD - clearing actions.  unit attn, see 4.10 */
471 }
472 
473 /*
474  * Handle incoming FCP request.
475  * Caller has verified that the frame is type FCP.
476  */
477 static void ft_recv(struct fc_lport *lport, struct fc_frame *fp)
478 {
479 	struct ft_sess *sess;
480 	u32 sid = fc_frame_sid(fp);
481 
482 	pr_debug("sid %x\n", sid);
483 
484 	sess = ft_sess_get(lport, sid);
485 	if (!sess) {
486 		pr_debug("sid %x sess lookup failed\n", sid);
487 		/* TBD XXX - if FCP_CMND, send PRLO */
488 		fc_frame_free(fp);
489 		return;
490 	}
491 	ft_recv_req(sess, fp);	/* must do ft_sess_put() */
492 }
493 
494 /*
495  * Provider ops for libfc.
496  */
497 struct fc4_prov ft_prov = {
498 	.prli = ft_prli,
499 	.prlo = ft_prlo,
500 	.recv = ft_recv,
501 	.module = THIS_MODULE,
502 };
503