drivers/target/tcm_fc/tfc_sess.c

   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 <generated/utsrelease.h>
  23 #include <linux/utsname.h>
  24 #include <linux/init.h>
  25 #include <linux/slab.h>
  26 #include <linux/kthread.h>
  27 #include <linux/types.h>
  28 #include <linux/string.h>
  29 #include <linux/configfs.h>
  30 #include <linux/ctype.h>
  31 #include <linux/hash.h>
  32 #include <linux/rcupdate.h>
  33 #include <linux/rculist.h>
  34 #include <linux/kref.h>
  35 #include <asm/unaligned.h>
  36 #include <scsi/scsi.h>
  37 #include <scsi/scsi_host.h>
  38 #include <scsi/scsi_device.h>
  39 #include <scsi/scsi_cmnd.h>
  40 #include <scsi/libfc.h>
  41
  42 #include <target/target_core_base.h>
  43 #include <target/target_core_fabric.h>
  44 #include <target/target_core_configfs.h>
  45 #include <target/configfs_macros.h>
  46
  47 #include "tcm_fc.h"
  48
  49 static void ft_sess_delete_all(struct ft_tport *);
  50
  51 /*
  52  * Lookup or allocate target local port.
  53  * Caller holds ft_lport_lock.
  54  */
  55 static struct ft_tport *ft_tport_create(struct fc_lport *lport)
  56 {
  57         struct ft_tpg *tpg;
  58         struct ft_tport *tport;
  59         int i;
  60
  61         tport = rcu_dereference(lport->prov[FC_TYPE_FCP]);
  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  * Free tport via RCU.
  90  */
  91 static void ft_tport_rcu_free(struct rcu_head *rcu)
  92 {
  93         struct ft_tport *tport = container_of(rcu, struct ft_tport, rcu);
  94
  95         kfree(tport);
  96 }
  97
  98 /*
  99  * Delete a target local port.
 100  * Caller holds ft_lport_lock.
 101  */
 102 static void ft_tport_delete(struct ft_tport *tport)
 103 {
 104         struct fc_lport *lport;
 105         struct ft_tpg *tpg;
 106
 107         ft_sess_delete_all(tport);
 108         lport = tport->lport;
 109         BUG_ON(tport != lport->prov[FC_TYPE_FCP]);
 110         rcu_assign_pointer(lport->prov[FC_TYPE_FCP], NULL);
 111
 112         tpg = tport->tpg;
 113         if (tpg) {
 114                 tpg->tport = NULL;
 115                 tport->tpg = NULL;
 116         }
 117         call_rcu(&tport->rcu, ft_tport_rcu_free);
 118 }
 119
 120 /*
 121  * Add local port.
 122  * Called thru fc_lport_iterate().
 123  */
 124 void ft_lport_add(struct fc_lport *lport, void *arg)
 125 {
 126         mutex_lock(&ft_lport_lock);
 127         ft_tport_create(lport);
 128         mutex_unlock(&ft_lport_lock);
 129 }
 130
 131 /*
 132  * Delete local port.
 133  * Called thru fc_lport_iterate().
 134  */
 135 void ft_lport_del(struct fc_lport *lport, void *arg)
 136 {
 137         struct ft_tport *tport;
 138
 139         mutex_lock(&ft_lport_lock);
 140         tport = lport->prov[FC_TYPE_FCP];
 141         if (tport)
 142                 ft_tport_delete(tport);
 143         mutex_unlock(&ft_lport_lock);
 144 }
 145
 146 /*
 147  * Notification of local port change from libfc.
 148  * Create or delete local port and associated tport.
 149  */
 150 int ft_lport_notify(struct notifier_block *nb, unsigned long event, void *arg)
 151 {
 152         struct fc_lport *lport = arg;
 153
 154         switch (event) {
 155         case FC_LPORT_EV_ADD:
 156                 ft_lport_add(lport, NULL);
 157                 break;
 158         case FC_LPORT_EV_DEL:
 159                 ft_lport_del(lport, NULL);
 160                 break;
 161         }
 162         return NOTIFY_DONE;
 163 }
 164
 165 /*
 166  * Hash function for FC_IDs.
 167  */
 168 static u32 ft_sess_hash(u32 port_id)
 169 {
 170         return hash_32(port_id, FT_SESS_HASH_BITS);
 171 }
 172
 173 /*
 174  * Find session in local port.
 175  * Sessions and hash lists are RCU-protected.
 176  * A reference is taken which must be eventually freed.
 177  */
 178 static struct ft_sess *ft_sess_get(struct fc_lport *lport, u32 port_id)
 179 {
 180         struct ft_tport *tport;
 181         struct hlist_head *head;
 182         struct hlist_node *pos;
 183         struct ft_sess *sess;
 184
 185         rcu_read_lock();
 186         tport = rcu_dereference(lport->prov[FC_TYPE_FCP]);
 187         if (!tport)
 188                 goto out;
 189
 190         head = &tport->hash[ft_sess_hash(port_id)];
 191         hlist_for_each_entry_rcu(sess, pos, head, hash) {
 192                 if (sess->port_id == port_id) {
 193                         kref_get(&sess->kref);
 194                         rcu_read_unlock();
 195                         pr_debug("port_id %x found %p\n", port_id, sess);
 196                         return sess;
 197                 }
 198         }
 199 out:
 200         rcu_read_unlock();
 201         pr_debug("port_id %x not found\n", port_id);
 202         return NULL;
 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 ft_node_acl *acl)
 211 {
 212         struct ft_sess *sess;
 213         struct hlist_head *head;
 214         struct hlist_node *pos;
 215
 216         head = &tport->hash[ft_sess_hash(port_id)];
 217         hlist_for_each_entry_rcu(sess, pos, head, hash)
 218                 if (sess->port_id == port_id)
 219                         return sess;
 220
 221         sess = kzalloc(sizeof(*sess), GFP_KERNEL);
 222         if (!sess)
 223                 return NULL;
 224
 225         sess->se_sess = transport_init_session();
 226         if (IS_ERR(sess->se_sess)) {
 227                 kfree(sess);
 228                 return NULL;
 229         }
 230         sess->se_sess->se_node_acl = &acl->se_node_acl;
 231         sess->tport = tport;
 232         sess->port_id = port_id;
 233         kref_init(&sess->kref); /* ref for table entry */
 234         hlist_add_head_rcu(&sess->hash, head);
 235         tport->sess_count++;
 236
 237         pr_debug("port_id %x sess %p\n", port_id, sess);
 238
 239         transport_register_session(&tport->tpg->se_tpg, &acl->se_node_acl,
 240                                    sess->se_sess, sess);
 241         return sess;
 242 }
 243
 244 /*
 245  * Unhash the session.
 246  * Caller holds ft_lport_lock.
 247  */
 248 static void ft_sess_unhash(struct ft_sess *sess)
 249 {
 250         struct ft_tport *tport = sess->tport;
 251
 252         hlist_del_rcu(&sess->hash);
 253         BUG_ON(!tport->sess_count);
 254         tport->sess_count--;
 255         sess->port_id = -1;
 256         sess->params = 0;
 257 }
 258
 259 /*
 260  * Delete session from hash.
 261  * Caller holds ft_lport_lock.
 262  */
 263 static struct ft_sess *ft_sess_delete(struct ft_tport *tport, u32 port_id)
 264 {
 265         struct hlist_head *head;
 266         struct hlist_node *pos;
 267         struct ft_sess *sess;
 268
 269         head = &tport->hash[ft_sess_hash(port_id)];
 270         hlist_for_each_entry_rcu(sess, pos, head, hash) {
 271                 if (sess->port_id == port_id) {
 272                         ft_sess_unhash(sess);
 273                         return sess;
 274                 }
 275         }
 276         return NULL;
 277 }
 278
 279 /*
 280  * Delete all sessions from tport.
 281  * Caller holds ft_lport_lock.
 282  */
 283 static void ft_sess_delete_all(struct ft_tport *tport)
 284 {
 285         struct hlist_head *head;
 286         struct hlist_node *pos;
 287         struct ft_sess *sess;
 288
 289         for (head = tport->hash;
 290              head < &tport->hash[FT_SESS_HASH_SIZE]; head++) {
 291                 hlist_for_each_entry_rcu(sess, pos, head, hash) {
 292                         ft_sess_unhash(sess);
 293                         transport_deregister_session_configfs(sess->se_sess);
 294                         ft_sess_put(sess);      /* release from table */
 295                 }
 296         }
 297 }
 298
 299 /*
 300  * TCM ops for sessions.
 301  */
 302
 303 /*
 304  * Determine whether session is allowed to be shutdown in the current context.
 305  * Returns non-zero if the session should be shutdown.
 306  */
 307 int ft_sess_shutdown(struct se_session *se_sess)
 308 {
 309         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 310
 311         pr_debug("port_id %x\n", sess->port_id);
 312         return 1;
 313 }
 314
 315 /*
 316  * Remove session and send PRLO.
 317  * This is called when the ACL is being deleted or queue depth is changing.
 318  */
 319 void ft_sess_close(struct se_session *se_sess)
 320 {
 321         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 322         struct fc_lport *lport;
 323         u32 port_id;
 324
 325         mutex_lock(&ft_lport_lock);
 326         lport = sess->tport->lport;
 327         port_id = sess->port_id;
 328         if (port_id == -1) {
 329                 mutex_unlock(&ft_lport_lock);
 330                 return;
 331         }
 332         pr_debug("port_id %x\n", port_id);
 333         ft_sess_unhash(sess);
 334         mutex_unlock(&ft_lport_lock);
 335         transport_deregister_session_configfs(se_sess);
 336         ft_sess_put(sess);
 337         /* XXX Send LOGO or PRLO */
 338         synchronize_rcu();              /* let transport deregister happen */
 339 }
 340
 341 u32 ft_sess_get_index(struct se_session *se_sess)
 342 {
 343         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 344
 345         return sess->port_id;   /* XXX TBD probably not what is needed */
 346 }
 347
 348 u32 ft_sess_get_port_name(struct se_session *se_sess,
 349                           unsigned char *buf, u32 len)
 350 {
 351         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 352
 353         return ft_format_wwn(buf, len, sess->port_name);
 354 }
 355
 356 /*
 357  * libfc ops involving sessions.
 358  */
 359
 360 static int ft_prli_locked(struct fc_rport_priv *rdata, u32 spp_len,
 361                           const struct fc_els_spp *rspp, struct fc_els_spp *spp)
 362 {
 363         struct ft_tport *tport;
 364         struct ft_sess *sess;
 365         struct ft_node_acl *acl;
 366         u32 fcp_parm;
 367
 368         tport = ft_tport_create(rdata->local_port);
 369         if (!tport)
 370                 return 0;       /* not a target for this local port */
 371
 372         acl = ft_acl_get(tport->tpg, rdata);
 373         if (!acl)
 374                 return 0;
 375
 376         if (!rspp)
 377                 goto fill;
 378
 379         if (rspp->spp_flags & (FC_SPP_OPA_VAL | FC_SPP_RPA_VAL))
 380                 return FC_SPP_RESP_NO_PA;
 381
 382         /*
 383          * If both target and initiator bits are off, the SPP is invalid.
 384          */
 385         fcp_parm = ntohl(rspp->spp_params);
 386         if (!(fcp_parm & (FCP_SPPF_INIT_FCN | FCP_SPPF_TARG_FCN)))
 387                 return FC_SPP_RESP_INVL;
 388
 389         /*
 390          * Create session (image pair) only if requested by
 391          * EST_IMG_PAIR flag and if the requestor is an initiator.
 392          */
 393         if (rspp->spp_flags & FC_SPP_EST_IMG_PAIR) {
 394                 spp->spp_flags |= FC_SPP_EST_IMG_PAIR;
 395                 if (!(fcp_parm & FCP_SPPF_INIT_FCN))
 396                         return FC_SPP_RESP_CONF;
 397                 sess = ft_sess_create(tport, rdata->ids.port_id, acl);
 398                 if (!sess)
 399                         return FC_SPP_RESP_RES;
 400                 if (!sess->params)
 401                         rdata->prli_count++;
 402                 sess->params = fcp_parm;
 403                 sess->port_name = rdata->ids.port_name;
 404                 sess->max_frame = rdata->maxframe_size;
 405
 406                 /* XXX TBD - clearing actions.  unit attn, see 4.10 */
 407         }
 408
 409         /*
 410          * OR in our service parameters with other provider (initiator), if any.
 411          * TBD XXX - indicate RETRY capability?
 412          */
 413 fill:
 414         fcp_parm = ntohl(spp->spp_params);
 415         spp->spp_params = htonl(fcp_parm | FCP_SPPF_TARG_FCN);
 416         return FC_SPP_RESP_ACK;
 417 }
 418
 419 /**
 420  * tcm_fcp_prli() - Handle incoming or outgoing PRLI for the FCP target
 421  * @rdata: remote port private
 422  * @spp_len: service parameter page length
 423  * @rspp: received service parameter page (NULL for outgoing PRLI)
 424  * @spp: response service parameter page
 425  *
 426  * Returns spp response code.
 427  */
 428 static int ft_prli(struct fc_rport_priv *rdata, u32 spp_len,
 429                    const struct fc_els_spp *rspp, struct fc_els_spp *spp)
 430 {
 431         int ret;
 432
 433         mutex_lock(&ft_lport_lock);
 434         ret = ft_prli_locked(rdata, spp_len, rspp, spp);
 435         mutex_unlock(&ft_lport_lock);
 436         pr_debug("port_id %x flags %x ret %x\n",
 437                rdata->ids.port_id, rspp ? rspp->spp_flags : 0, ret);
 438         return ret;
 439 }
 440
 441 static void ft_sess_rcu_free(struct rcu_head *rcu)
 442 {
 443         struct ft_sess *sess = container_of(rcu, struct ft_sess, rcu);
 444
 445         transport_deregister_session(sess->se_sess);
 446         kfree(sess);
 447 }
 448
 449 static void ft_sess_free(struct kref *kref)
 450 {
 451         struct ft_sess *sess = container_of(kref, struct ft_sess, kref);
 452
 453         call_rcu(&sess->rcu, ft_sess_rcu_free);
 454 }
 455
 456 void ft_sess_put(struct ft_sess *sess)
 457 {
 458         int sess_held = atomic_read(&sess->kref.refcount);
 459
 460         BUG_ON(!sess_held);
 461         kref_put(&sess->kref, ft_sess_free);
 462 }
 463
 464 static void ft_prlo(struct fc_rport_priv *rdata)
 465 {
 466         struct ft_sess *sess;
 467         struct ft_tport *tport;
 468
 469         mutex_lock(&ft_lport_lock);
 470         tport = rcu_dereference(rdata->local_port->prov[FC_TYPE_FCP]);
 471         if (!tport) {
 472                 mutex_unlock(&ft_lport_lock);
 473                 return;
 474         }
 475         sess = ft_sess_delete(tport, rdata->ids.port_id);
 476         if (!sess) {
 477                 mutex_unlock(&ft_lport_lock);
 478                 return;
 479         }
 480         mutex_unlock(&ft_lport_lock);
 481         transport_deregister_session_configfs(sess->se_sess);
 482         ft_sess_put(sess);              /* release from table */
 483         rdata->prli_count--;
 484         /* XXX TBD - clearing actions.  unit attn, see 4.10 */
 485 }
 486
 487 /*
 488  * Handle incoming FCP request.
 489  * Caller has verified that the frame is type FCP.
 490  */
 491 static void ft_recv(struct fc_lport *lport, struct fc_frame *fp)
 492 {
 493         struct ft_sess *sess;
 494         u32 sid = fc_frame_sid(fp);
 495
 496         pr_debug("sid %x\n", sid);
 497
 498         sess = ft_sess_get(lport, sid);
 499         if (!sess) {
 500                 pr_debug("sid %x sess lookup failed\n", sid);
 501                 /* TBD XXX - if FCP_CMND, send PRLO */
 502                 fc_frame_free(fp);
 503                 return;
 504         }
 505         ft_recv_req(sess, fp);  /* must do ft_sess_put() */
 506 }
 507
 508 /*
 509  * Provider ops for libfc.
 510  */
 511 struct fc4_prov ft_prov = {
 512         .prli = ft_prli,
 513         .prlo = ft_prlo,
 514         .recv = ft_recv,
 515         .module = THIS_MODULE,
 516 };