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 <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         BUG_ON(tport != lport->prov[FC_TYPE_FCP]);
  95         RCU_INIT_POINTER(lport->prov[FC_TYPE_FCP], NULL);
  96
  97         tpg = tport->tpg;
  98         if (tpg) {
  99                 tpg->tport = NULL;
 100                 tport->tpg = NULL;
 101         }
 102         kfree_rcu(tport, rcu);
 103 }
 104
 105 /*
 106  * Add local port.
 107  * Called thru fc_lport_iterate().
 108  */
 109 void ft_lport_add(struct fc_lport *lport, void *arg)
 110 {
 111         mutex_lock(&ft_lport_lock);
 112         ft_tport_get(lport);
 113         mutex_unlock(&ft_lport_lock);
 114 }
 115
 116 /*
 117  * Delete local port.
 118  * Called thru fc_lport_iterate().
 119  */
 120 void ft_lport_del(struct fc_lport *lport, void *arg)
 121 {
 122         struct ft_tport *tport;
 123
 124         mutex_lock(&ft_lport_lock);
 125         tport = lport->prov[FC_TYPE_FCP];
 126         if (tport)
 127                 ft_tport_delete(tport);
 128         mutex_unlock(&ft_lport_lock);
 129 }
 130
 131 /*
 132  * Notification of local port change from libfc.
 133  * Create or delete local port and associated tport.
 134  */
 135 int ft_lport_notify(struct notifier_block *nb, unsigned long event, void *arg)
 136 {
 137         struct fc_lport *lport = arg;
 138
 139         switch (event) {
 140         case FC_LPORT_EV_ADD:
 141                 ft_lport_add(lport, NULL);
 142                 break;
 143         case FC_LPORT_EV_DEL:
 144                 ft_lport_del(lport, NULL);
 145                 break;
 146         }
 147         return NOTIFY_DONE;
 148 }
 149
 150 /*
 151  * Hash function for FC_IDs.
 152  */
 153 static u32 ft_sess_hash(u32 port_id)
 154 {
 155         return hash_32(port_id, FT_SESS_HASH_BITS);
 156 }
 157
 158 /*
 159  * Find session in local port.
 160  * Sessions and hash lists are RCU-protected.
 161  * A reference is taken which must be eventually freed.
 162  */
 163 static struct ft_sess *ft_sess_get(struct fc_lport *lport, u32 port_id)
 164 {
 165         struct ft_tport *tport;
 166         struct hlist_head *head;
 167         struct ft_sess *sess;
 168
 169         rcu_read_lock();
 170         tport = rcu_dereference(lport->prov[FC_TYPE_FCP]);
 171         if (!tport)
 172                 goto out;
 173
 174         head = &tport->hash[ft_sess_hash(port_id)];
 175         hlist_for_each_entry_rcu(sess, head, hash) {
 176                 if (sess->port_id == port_id) {
 177                         kref_get(&sess->kref);
 178                         rcu_read_unlock();
 179                         pr_debug("port_id %x found %p\n", port_id, sess);
 180                         return sess;
 181                 }
 182         }
 183 out:
 184         rcu_read_unlock();
 185         pr_debug("port_id %x not found\n", port_id);
 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         pr_debug("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 NULL;
 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_alloc_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                 kfree(sess);
 236                 return NULL;
 237         }
 238         return sess;
 239 }
 240
 241 /*
 242  * Unhash the session.
 243  * Caller holds ft_lport_lock.
 244  */
 245 static void ft_sess_unhash(struct ft_sess *sess)
 246 {
 247         struct ft_tport *tport = sess->tport;
 248
 249         hlist_del_rcu(&sess->hash);
 250         BUG_ON(!tport->sess_count);
 251         tport->sess_count--;
 252         sess->port_id = -1;
 253         sess->params = 0;
 254 }
 255
 256 /*
 257  * Delete session from hash.
 258  * Caller holds ft_lport_lock.
 259  */
 260 static struct ft_sess *ft_sess_delete(struct ft_tport *tport, u32 port_id)
 261 {
 262         struct hlist_head *head;
 263         struct ft_sess *sess;
 264
 265         head = &tport->hash[ft_sess_hash(port_id)];
 266         hlist_for_each_entry_rcu(sess, head, hash) {
 267                 if (sess->port_id == port_id) {
 268                         ft_sess_unhash(sess);
 269                         return sess;
 270                 }
 271         }
 272         return NULL;
 273 }
 274
 275 static void ft_close_sess(struct ft_sess *sess)
 276 {
 277         transport_deregister_session_configfs(sess->se_sess);
 278         target_sess_cmd_list_set_waiting(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  * Determine whether session is allowed to be shutdown in the current context.
 307  * Returns non-zero if the session should be shutdown.
 308  */
 309 int ft_sess_shutdown(struct se_session *se_sess)
 310 {
 311         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 312
 313         pr_debug("port_id %x\n", sess->port_id);
 314         return 1;
 315 }
 316
 317 /*
 318  * Remove session and send PRLO.
 319  * This is called when the ACL is being deleted or queue depth is changing.
 320  */
 321 void ft_sess_close(struct se_session *se_sess)
 322 {
 323         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 324         u32 port_id;
 325
 326         mutex_lock(&ft_lport_lock);
 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         ft_close_sess(sess);
 336         /* XXX Send LOGO or PRLO */
 337         synchronize_rcu();              /* let transport deregister happen */
 338 }
 339
 340 u32 ft_sess_get_index(struct se_session *se_sess)
 341 {
 342         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 343
 344         return sess->port_id;   /* XXX TBD probably not what is needed */
 345 }
 346
 347 u32 ft_sess_get_port_name(struct se_session *se_sess,
 348                           unsigned char *buf, u32 len)
 349 {
 350         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 351
 352         return ft_format_wwn(buf, len, sess->port_name);
 353 }
 354
 355 /*
 356  * libfc ops involving sessions.
 357  */
 358
 359 static int ft_prli_locked(struct fc_rport_priv *rdata, u32 spp_len,
 360                           const struct fc_els_spp *rspp, struct fc_els_spp *spp)
 361 {
 362         struct ft_tport *tport;
 363         struct ft_sess *sess;
 364         u32 fcp_parm;
 365
 366         tport = ft_tport_get(rdata->local_port);
 367         if (!tport)
 368                 goto not_target;        /* not a target for this local port */
 369
 370         if (!rspp)
 371                 goto fill;
 372
 373         if (rspp->spp_flags & (FC_SPP_OPA_VAL | FC_SPP_RPA_VAL))
 374                 return FC_SPP_RESP_NO_PA;
 375
 376         /*
 377          * If both target and initiator bits are off, the SPP is invalid.
 378          */
 379         fcp_parm = ntohl(rspp->spp_params);
 380         if (!(fcp_parm & (FCP_SPPF_INIT_FCN | FCP_SPPF_TARG_FCN)))
 381                 return FC_SPP_RESP_INVL;
 382
 383         /*
 384          * Create session (image pair) only if requested by
 385          * EST_IMG_PAIR flag and if the requestor is an initiator.
 386          */
 387         if (rspp->spp_flags & FC_SPP_EST_IMG_PAIR) {
 388                 spp->spp_flags |= FC_SPP_EST_IMG_PAIR;
 389                 if (!(fcp_parm & FCP_SPPF_INIT_FCN))
 390                         return FC_SPP_RESP_CONF;
 391                 sess = ft_sess_create(tport, rdata->ids.port_id, rdata);
 392                 if (!sess)
 393                         return FC_SPP_RESP_RES;
 394                 if (!sess->params)
 395                         rdata->prli_count++;
 396                 sess->params = fcp_parm;
 397                 sess->port_name = rdata->ids.port_name;
 398                 sess->max_frame = rdata->maxframe_size;
 399
 400                 /* XXX TBD - clearing actions.  unit attn, see 4.10 */
 401         }
 402
 403         /*
 404          * OR in our service parameters with other provider (initiator), if any.
 405          */
 406 fill:
 407         fcp_parm = ntohl(spp->spp_params);
 408         fcp_parm &= ~FCP_SPPF_RETRY;
 409         spp->spp_params = htonl(fcp_parm | FCP_SPPF_TARG_FCN);
 410         return FC_SPP_RESP_ACK;
 411
 412 not_target:
 413         fcp_parm = ntohl(spp->spp_params);
 414         fcp_parm &= ~FCP_SPPF_TARG_FCN;
 415         spp->spp_params = htonl(fcp_parm);
 416         return 0;
 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_free(struct kref *kref)
 442 {
 443         struct ft_sess *sess = container_of(kref, struct ft_sess, kref);
 444
 445         transport_deregister_session(sess->se_sess);
 446         kfree_rcu(sess, rcu);
 447 }
 448
 449 void ft_sess_put(struct ft_sess *sess)
 450 {
 451         int sess_held = atomic_read(&sess->kref.refcount);
 452
 453         BUG_ON(!sess_held);
 454         kref_put(&sess->kref, ft_sess_free);
 455 }
 456
 457 static void ft_prlo(struct fc_rport_priv *rdata)
 458 {
 459         struct ft_sess *sess;
 460         struct ft_tport *tport;
 461
 462         mutex_lock(&ft_lport_lock);
 463         tport = rcu_dereference_protected(rdata->local_port->prov[FC_TYPE_FCP],
 464                                           lockdep_is_held(&ft_lport_lock));
 465
 466         if (!tport) {
 467                 mutex_unlock(&ft_lport_lock);
 468                 return;
 469         }
 470         sess = ft_sess_delete(tport, rdata->ids.port_id);
 471         if (!sess) {
 472                 mutex_unlock(&ft_lport_lock);
 473                 return;
 474         }
 475         mutex_unlock(&ft_lport_lock);
 476         ft_close_sess(sess);            /* release from table */
 477         rdata->prli_count--;
 478         /* XXX TBD - clearing actions.  unit attn, see 4.10 */
 479 }
 480
 481 /*
 482  * Handle incoming FCP request.
 483  * Caller has verified that the frame is type FCP.
 484  */
 485 static void ft_recv(struct fc_lport *lport, struct fc_frame *fp)
 486 {
 487         struct ft_sess *sess;
 488         u32 sid = fc_frame_sid(fp);
 489
 490         pr_debug("sid %x\n", sid);
 491
 492         sess = ft_sess_get(lport, sid);
 493         if (!sess) {
 494                 pr_debug("sid %x sess lookup failed\n", sid);
 495                 /* TBD XXX - if FCP_CMND, send PRLO */
 496                 fc_frame_free(fp);
 497                 return;
 498         }
 499         ft_recv_req(sess, fp);  /* must do ft_sess_put() */
 500 }
 501
 502 /*
 503  * Provider ops for libfc.
 504  */
 505 struct fc4_prov ft_prov = {
 506         .prli = ft_prli,
 507         .prlo = ft_prlo,
 508         .recv = ft_recv,
 509         .module = THIS_MODULE,
 510 };