xref: /linux/drivers/target/tcm_fc/tfc_sess.c (revision 8e07e0e3964ca4e23ce7b68e2096fe660a888942) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2010 Cisco Systems, Inc.
4  */
5 
6 /* XXX TBD some includes may be extraneous */
7 
8 #include <linux/module.h>
9 #include <linux/moduleparam.h>
10 #include <linux/utsname.h>
11 #include <linux/init.h>
12 #include <linux/slab.h>
13 #include <linux/kthread.h>
14 #include <linux/types.h>
15 #include <linux/string.h>
16 #include <linux/configfs.h>
17 #include <linux/ctype.h>
18 #include <linux/hash.h>
19 #include <linux/rcupdate.h>
20 #include <linux/rculist.h>
21 #include <linux/kref.h>
22 #include <asm/unaligned.h>
23 #include <scsi/libfc.h>
24 
25 #include <target/target_core_base.h>
26 #include <target/target_core_fabric.h>
27 
28 #include "tcm_fc.h"
29 
30 #define TFC_SESS_DBG(lport, fmt, args...) \
31 	pr_debug("host%u: rport %6.6x: " fmt,	   \
32 		 (lport)->host->host_no,	   \
33 		 (lport)->port_id, ##args )
34 
35 static void ft_sess_delete_all(struct ft_tport *);
36 
37 /*
38  * Lookup or allocate target local port.
39  * Caller holds ft_lport_lock.
40  */
41 static struct ft_tport *ft_tport_get(struct fc_lport *lport)
42 {
43 	struct ft_tpg *tpg;
44 	struct ft_tport *tport;
45 	int i;
46 
47 	tport = rcu_dereference_protected(lport->prov[FC_TYPE_FCP],
48 					  lockdep_is_held(&ft_lport_lock));
49 	if (tport && tport->tpg)
50 		return tport;
51 
52 	tpg = ft_lport_find_tpg(lport);
53 	if (!tpg)
54 		return NULL;
55 
56 	if (tport) {
57 		tport->tpg = tpg;
58 		tpg->tport = tport;
59 		return tport;
60 	}
61 
62 	tport = kzalloc(sizeof(*tport), GFP_KERNEL);
63 	if (!tport)
64 		return NULL;
65 
66 	tport->lport = lport;
67 	tport->tpg = tpg;
68 	tpg->tport = tport;
69 	for (i = 0; i < FT_SESS_HASH_SIZE; i++)
70 		INIT_HLIST_HEAD(&tport->hash[i]);
71 
72 	rcu_assign_pointer(lport->prov[FC_TYPE_FCP], tport);
73 	return tport;
74 }
75 
76 /*
77  * Delete a target local port.
78  * Caller holds ft_lport_lock.
79  */
80 static void ft_tport_delete(struct ft_tport *tport)
81 {
82 	struct fc_lport *lport;
83 	struct ft_tpg *tpg;
84 
85 	ft_sess_delete_all(tport);
86 	lport = tport->lport;
87 	lport->service_params &= ~FCP_SPPF_TARG_FCN;
88 	BUG_ON(tport != lport->prov[FC_TYPE_FCP]);
89 	RCU_INIT_POINTER(lport->prov[FC_TYPE_FCP], NULL);
90 
91 	tpg = tport->tpg;
92 	if (tpg) {
93 		tpg->tport = NULL;
94 		tport->tpg = NULL;
95 	}
96 	kfree_rcu(tport, rcu);
97 }
98 
99 /*
100  * Add local port.
101  * Called thru fc_lport_iterate().
102  */
103 void ft_lport_add(struct fc_lport *lport, void *arg)
104 {
105 	mutex_lock(&ft_lport_lock);
106 	ft_tport_get(lport);
107 	lport->service_params |= FCP_SPPF_TARG_FCN;
108 	mutex_unlock(&ft_lport_lock);
109 }
110 
111 /*
112  * Delete local port.
113  * Called thru fc_lport_iterate().
114  */
115 void ft_lport_del(struct fc_lport *lport, void *arg)
116 {
117 	struct ft_tport *tport;
118 
119 	mutex_lock(&ft_lport_lock);
120 	tport = lport->prov[FC_TYPE_FCP];
121 	if (tport)
122 		ft_tport_delete(tport);
123 	mutex_unlock(&ft_lport_lock);
124 }
125 
126 /*
127  * Notification of local port change from libfc.
128  * Create or delete local port and associated tport.
129  */
130 int ft_lport_notify(struct notifier_block *nb, unsigned long event, void *arg)
131 {
132 	struct fc_lport *lport = arg;
133 
134 	switch (event) {
135 	case FC_LPORT_EV_ADD:
136 		ft_lport_add(lport, NULL);
137 		break;
138 	case FC_LPORT_EV_DEL:
139 		ft_lport_del(lport, NULL);
140 		break;
141 	}
142 	return NOTIFY_DONE;
143 }
144 
145 /*
146  * Hash function for FC_IDs.
147  */
148 static u32 ft_sess_hash(u32 port_id)
149 {
150 	return hash_32(port_id, FT_SESS_HASH_BITS);
151 }
152 
153 /*
154  * Find session in local port.
155  * Sessions and hash lists are RCU-protected.
156  * A reference is taken which must be eventually freed.
157  */
158 static struct ft_sess *ft_sess_get(struct fc_lport *lport, u32 port_id)
159 {
160 	struct ft_tport *tport;
161 	struct hlist_head *head;
162 	struct ft_sess *sess;
163 	char *reason = "no session created";
164 
165 	rcu_read_lock();
166 	tport = rcu_dereference(lport->prov[FC_TYPE_FCP]);
167 	if (!tport) {
168 		reason = "not an FCP port";
169 		goto out;
170 	}
171 
172 	head = &tport->hash[ft_sess_hash(port_id)];
173 	hlist_for_each_entry_rcu(sess, head, hash) {
174 		if (sess->port_id == port_id) {
175 			kref_get(&sess->kref);
176 			rcu_read_unlock();
177 			TFC_SESS_DBG(lport, "port_id %x found %p\n",
178 				     port_id, sess);
179 			return sess;
180 		}
181 	}
182 out:
183 	rcu_read_unlock();
184 	TFC_SESS_DBG(lport, "port_id %x not found, %s\n",
185 		     port_id, reason);
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 	TFC_SESS_DBG(tport->lport, "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 ERR_PTR(-ENOMEM);
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_setup_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 		int rc = PTR_ERR(sess->se_sess);
236 		kfree(sess);
237 		sess = ERR_PTR(rc);
238 	}
239 	return sess;
240 }
241 
242 /*
243  * Unhash the session.
244  * Caller holds ft_lport_lock.
245  */
246 static void ft_sess_unhash(struct ft_sess *sess)
247 {
248 	struct ft_tport *tport = sess->tport;
249 
250 	hlist_del_rcu(&sess->hash);
251 	BUG_ON(!tport->sess_count);
252 	tport->sess_count--;
253 	sess->port_id = -1;
254 	sess->params = 0;
255 }
256 
257 /*
258  * Delete session from hash.
259  * Caller holds ft_lport_lock.
260  */
261 static struct ft_sess *ft_sess_delete(struct ft_tport *tport, u32 port_id)
262 {
263 	struct hlist_head *head;
264 	struct ft_sess *sess;
265 
266 	head = &tport->hash[ft_sess_hash(port_id)];
267 	hlist_for_each_entry_rcu(sess, head, hash) {
268 		if (sess->port_id == port_id) {
269 			ft_sess_unhash(sess);
270 			return sess;
271 		}
272 	}
273 	return NULL;
274 }
275 
276 static void ft_close_sess(struct ft_sess *sess)
277 {
278 	target_stop_session(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 	TFC_SESS_DBG(sess->tport->lport, "port_id %x close session\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 (IS_ERR(sess)) {
381 			if (PTR_ERR(sess) == -EACCES) {
382 				spp->spp_flags &= ~FC_SPP_EST_IMG_PAIR;
383 				return FC_SPP_RESP_CONF;
384 			} else
385 				return FC_SPP_RESP_RES;
386 		}
387 		if (!sess->params)
388 			rdata->prli_count++;
389 		sess->params = fcp_parm;
390 		sess->port_name = rdata->ids.port_name;
391 		sess->max_frame = rdata->maxframe_size;
392 
393 		/* XXX TBD - clearing actions.  unit attn, see 4.10 */
394 	}
395 
396 	/*
397 	 * OR in our service parameters with other provider (initiator), if any.
398 	 */
399 fill:
400 	fcp_parm = ntohl(spp->spp_params);
401 	fcp_parm &= ~FCP_SPPF_RETRY;
402 	spp->spp_params = htonl(fcp_parm | FCP_SPPF_TARG_FCN);
403 	return FC_SPP_RESP_ACK;
404 
405 not_target:
406 	fcp_parm = ntohl(spp->spp_params);
407 	fcp_parm &= ~FCP_SPPF_TARG_FCN;
408 	spp->spp_params = htonl(fcp_parm);
409 	return 0;
410 }
411 
412 /**
413  * ft_prli() - Handle incoming or outgoing PRLI for the FCP target
414  * @rdata: remote port private
415  * @spp_len: service parameter page length
416  * @rspp: received service parameter page (NULL for outgoing PRLI)
417  * @spp: response service parameter page
418  *
419  * Returns spp response code.
420  */
421 static int ft_prli(struct fc_rport_priv *rdata, u32 spp_len,
422 		   const struct fc_els_spp *rspp, struct fc_els_spp *spp)
423 {
424 	int ret;
425 
426 	mutex_lock(&ft_lport_lock);
427 	ret = ft_prli_locked(rdata, spp_len, rspp, spp);
428 	mutex_unlock(&ft_lport_lock);
429 	TFC_SESS_DBG(rdata->local_port, "port_id %x flags %x ret %x\n",
430 		     rdata->ids.port_id, rspp ? rspp->spp_flags : 0, ret);
431 	return ret;
432 }
433 
434 static void ft_sess_free(struct kref *kref)
435 {
436 	struct ft_sess *sess = container_of(kref, struct ft_sess, kref);
437 
438 	target_remove_session(sess->se_sess);
439 	kfree_rcu(sess, rcu);
440 }
441 
442 void ft_sess_put(struct ft_sess *sess)
443 {
444 	int sess_held = kref_read(&sess->kref);
445 
446 	BUG_ON(!sess_held);
447 	kref_put(&sess->kref, ft_sess_free);
448 }
449 
450 static void ft_prlo(struct fc_rport_priv *rdata)
451 {
452 	struct ft_sess *sess;
453 	struct ft_tport *tport;
454 
455 	mutex_lock(&ft_lport_lock);
456 	tport = rcu_dereference_protected(rdata->local_port->prov[FC_TYPE_FCP],
457 					  lockdep_is_held(&ft_lport_lock));
458 
459 	if (!tport) {
460 		mutex_unlock(&ft_lport_lock);
461 		return;
462 	}
463 	sess = ft_sess_delete(tport, rdata->ids.port_id);
464 	if (!sess) {
465 		mutex_unlock(&ft_lport_lock);
466 		return;
467 	}
468 	mutex_unlock(&ft_lport_lock);
469 	ft_close_sess(sess);		/* release from table */
470 	rdata->prli_count--;
471 	/* XXX TBD - clearing actions.  unit attn, see 4.10 */
472 }
473 
474 /*
475  * Handle incoming FCP request.
476  * Caller has verified that the frame is type FCP.
477  */
478 static void ft_recv(struct fc_lport *lport, struct fc_frame *fp)
479 {
480 	struct ft_sess *sess;
481 	u32 sid = fc_frame_sid(fp);
482 
483 	TFC_SESS_DBG(lport, "recv sid %x\n", sid);
484 
485 	sess = ft_sess_get(lport, sid);
486 	if (!sess) {
487 		TFC_SESS_DBG(lport, "sid %x sess lookup failed\n", sid);
488 		/* TBD XXX - if FCP_CMND, send PRLO */
489 		fc_frame_free(fp);
490 		return;
491 	}
492 	ft_recv_req(sess, fp);	/* must do ft_sess_put() */
493 }
494 
495 /*
496  * Provider ops for libfc.
497  */
498 struct fc4_prov ft_prov = {
499 	.prli = ft_prli,
500 	.prlo = ft_prlo,
501 	.recv = ft_recv,
502 	.module = THIS_MODULE,
503 };
504