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 #define TFC_SESS_DBG(lport, fmt, args...) \
  43         pr_debug("host%u: rport %6.6x: " fmt,      \
  44                  (lport)->host->host_no,           \
  45                  (lport)->port_id, ##args )
  46
  47 static void ft_sess_delete_all(struct ft_tport *);
  48
  49 /*
  50  * Lookup or allocate target local port.
  51  * Caller holds ft_lport_lock.
  52  */
  53 static struct ft_tport *ft_tport_get(struct fc_lport *lport)
  54 {
  55         struct ft_tpg *tpg;
  56         struct ft_tport *tport;
  57         int i;
  58
  59         tport = rcu_dereference_protected(lport->prov[FC_TYPE_FCP],
  60                                           lockdep_is_held(&ft_lport_lock));
  61         if (tport && tport->tpg)
  62                 return tport;
  63
  64         tpg = ft_lport_find_tpg(lport);
  65         if (!tpg)
  66                 return NULL;
  67
  68         if (tport) {
  69                 tport->tpg = tpg;
  70                 tpg->tport = tport;
  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         lport->service_params &= ~FCP_SPPF_TARG_FCN;
 100         BUG_ON(tport != lport->prov[FC_TYPE_FCP]);
 101         RCU_INIT_POINTER(lport->prov[FC_TYPE_FCP], NULL);
 102
 103         tpg = tport->tpg;
 104         if (tpg) {
 105                 tpg->tport = NULL;
 106                 tport->tpg = NULL;
 107         }
 108         kfree_rcu(tport, rcu);
 109 }
 110
 111 /*
 112  * Add local port.
 113  * Called thru fc_lport_iterate().
 114  */
 115 void ft_lport_add(struct fc_lport *lport, void *arg)
 116 {
 117         mutex_lock(&ft_lport_lock);
 118         ft_tport_get(lport);
 119         lport->service_params |= FCP_SPPF_TARG_FCN;
 120         mutex_unlock(&ft_lport_lock);
 121 }
 122
 123 /*
 124  * Delete local port.
 125  * Called thru fc_lport_iterate().
 126  */
 127 void ft_lport_del(struct fc_lport *lport, void *arg)
 128 {
 129         struct ft_tport *tport;
 130
 131         mutex_lock(&ft_lport_lock);
 132         tport = lport->prov[FC_TYPE_FCP];
 133         if (tport)
 134                 ft_tport_delete(tport);
 135         mutex_unlock(&ft_lport_lock);
 136 }
 137
 138 /*
 139  * Notification of local port change from libfc.
 140  * Create or delete local port and associated tport.
 141  */
 142 int ft_lport_notify(struct notifier_block *nb, unsigned long event, void *arg)
 143 {
 144         struct fc_lport *lport = arg;
 145
 146         switch (event) {
 147         case FC_LPORT_EV_ADD:
 148                 ft_lport_add(lport, NULL);
 149                 break;
 150         case FC_LPORT_EV_DEL:
 151                 ft_lport_del(lport, NULL);
 152                 break;
 153         }
 154         return NOTIFY_DONE;
 155 }
 156
 157 /*
 158  * Hash function for FC_IDs.
 159  */
 160 static u32 ft_sess_hash(u32 port_id)
 161 {
 162         return hash_32(port_id, FT_SESS_HASH_BITS);
 163 }
 164
 165 /*
 166  * Find session in local port.
 167  * Sessions and hash lists are RCU-protected.
 168  * A reference is taken which must be eventually freed.
 169  */
 170 static struct ft_sess *ft_sess_get(struct fc_lport *lport, u32 port_id)
 171 {
 172         struct ft_tport *tport;
 173         struct hlist_head *head;
 174         struct ft_sess *sess;
 175         char *reason = "no session created";
 176
 177         rcu_read_lock();
 178         tport = rcu_dereference(lport->prov[FC_TYPE_FCP]);
 179         if (!tport) {
 180                 reason = "not an FCP port";
 181                 goto out;
 182         }
 183
 184         head = &tport->hash[ft_sess_hash(port_id)];
 185         hlist_for_each_entry_rcu(sess, head, hash) {
 186                 if (sess->port_id == port_id) {
 187                         kref_get(&sess->kref);
 188                         rcu_read_unlock();
 189                         TFC_SESS_DBG(lport, "port_id %x found %p\n",
 190                                      port_id, sess);
 191                         return sess;
 192                 }
 193         }
 194 out:
 195         rcu_read_unlock();
 196         TFC_SESS_DBG(lport, "port_id %x not found, %s\n",
 197                      port_id, reason);
 198         return NULL;
 199 }
 200
 201 static int ft_sess_alloc_cb(struct se_portal_group *se_tpg,
 202                             struct se_session *se_sess, void *p)
 203 {
 204         struct ft_sess *sess = p;
 205         struct ft_tport *tport = sess->tport;
 206         struct hlist_head *head = &tport->hash[ft_sess_hash(sess->port_id)];
 207
 208         TFC_SESS_DBG(tport->lport, "port_id %x sess %p\n", sess->port_id, sess);
 209         hlist_add_head_rcu(&sess->hash, head);
 210         tport->sess_count++;
 211
 212         return 0;
 213 }
 214
 215 /*
 216  * Allocate session and enter it in the hash for the local port.
 217  * Caller holds ft_lport_lock.
 218  */
 219 static struct ft_sess *ft_sess_create(struct ft_tport *tport, u32 port_id,
 220                                       struct fc_rport_priv *rdata)
 221 {
 222         struct se_portal_group *se_tpg = &tport->tpg->se_tpg;
 223         struct ft_sess *sess;
 224         struct hlist_head *head;
 225         unsigned char initiatorname[TRANSPORT_IQN_LEN];
 226
 227         ft_format_wwn(&initiatorname[0], TRANSPORT_IQN_LEN, rdata->ids.port_name);
 228
 229         head = &tport->hash[ft_sess_hash(port_id)];
 230         hlist_for_each_entry_rcu(sess, head, hash)
 231                 if (sess->port_id == port_id)
 232                         return sess;
 233
 234         sess = kzalloc(sizeof(*sess), GFP_KERNEL);
 235         if (!sess)
 236                 return ERR_PTR(-ENOMEM);
 237
 238         kref_init(&sess->kref); /* ref for table entry */
 239         sess->tport = tport;
 240         sess->port_id = port_id;
 241
 242         sess->se_sess = target_setup_session(se_tpg, TCM_FC_DEFAULT_TAGS,
 243                                              sizeof(struct ft_cmd),
 244                                              TARGET_PROT_NORMAL, &initiatorname[0],
 245                                              sess, ft_sess_alloc_cb);
 246         if (IS_ERR(sess->se_sess)) {
 247                 int rc = PTR_ERR(sess->se_sess);
 248                 kfree(sess);
 249                 sess = ERR_PTR(rc);
 250         }
 251         return sess;
 252 }
 253
 254 /*
 255  * Unhash the session.
 256  * Caller holds ft_lport_lock.
 257  */
 258 static void ft_sess_unhash(struct ft_sess *sess)
 259 {
 260         struct ft_tport *tport = sess->tport;
 261
 262         hlist_del_rcu(&sess->hash);
 263         BUG_ON(!tport->sess_count);
 264         tport->sess_count--;
 265         sess->port_id = -1;
 266         sess->params = 0;
 267 }
 268
 269 /*
 270  * Delete session from hash.
 271  * Caller holds ft_lport_lock.
 272  */
 273 static struct ft_sess *ft_sess_delete(struct ft_tport *tport, u32 port_id)
 274 {
 275         struct hlist_head *head;
 276         struct ft_sess *sess;
 277
 278         head = &tport->hash[ft_sess_hash(port_id)];
 279         hlist_for_each_entry_rcu(sess, head, hash) {
 280                 if (sess->port_id == port_id) {
 281                         ft_sess_unhash(sess);
 282                         return sess;
 283                 }
 284         }
 285         return NULL;
 286 }
 287
 288 static void ft_close_sess(struct ft_sess *sess)
 289 {
 290         target_sess_cmd_list_set_waiting(sess->se_sess);
 291         target_wait_for_sess_cmds(sess->se_sess);
 292         ft_sess_put(sess);
 293 }
 294
 295 /*
 296  * Delete all sessions from tport.
 297  * Caller holds ft_lport_lock.
 298  */
 299 static void ft_sess_delete_all(struct ft_tport *tport)
 300 {
 301         struct hlist_head *head;
 302         struct ft_sess *sess;
 303
 304         for (head = tport->hash;
 305              head < &tport->hash[FT_SESS_HASH_SIZE]; head++) {
 306                 hlist_for_each_entry_rcu(sess, head, hash) {
 307                         ft_sess_unhash(sess);
 308                         ft_close_sess(sess);    /* release from table */
 309                 }
 310         }
 311 }
 312
 313 /*
 314  * TCM ops for sessions.
 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         TFC_SESS_DBG(sess->tport->lport, "port_id %x close session\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 (IS_ERR(sess)) {
 393                         if (PTR_ERR(sess) == -EACCES) {
 394                                 spp->spp_flags &= ~FC_SPP_EST_IMG_PAIR;
 395                                 return FC_SPP_RESP_CONF;
 396                         } else
 397                                 return FC_SPP_RESP_RES;
 398                 }
 399                 if (!sess->params)
 400                         rdata->prli_count++;
 401                 sess->params = fcp_parm;
 402                 sess->port_name = rdata->ids.port_name;
 403                 sess->max_frame = rdata->maxframe_size;
 404
 405                 /* XXX TBD - clearing actions.  unit attn, see 4.10 */
 406         }
 407
 408         /*
 409          * OR in our service parameters with other provider (initiator), if any.
 410          */
 411 fill:
 412         fcp_parm = ntohl(spp->spp_params);
 413         fcp_parm &= ~FCP_SPPF_RETRY;
 414         spp->spp_params = htonl(fcp_parm | FCP_SPPF_TARG_FCN);
 415         return FC_SPP_RESP_ACK;
 416
 417 not_target:
 418         fcp_parm = ntohl(spp->spp_params);
 419         fcp_parm &= ~FCP_SPPF_TARG_FCN;
 420         spp->spp_params = htonl(fcp_parm);
 421         return 0;
 422 }
 423
 424 /**
 425  * tcm_fcp_prli() - Handle incoming or outgoing PRLI for the FCP target
 426  * @rdata: remote port private
 427  * @spp_len: service parameter page length
 428  * @rspp: received service parameter page (NULL for outgoing PRLI)
 429  * @spp: response service parameter page
 430  *
 431  * Returns spp response code.
 432  */
 433 static int ft_prli(struct fc_rport_priv *rdata, u32 spp_len,
 434                    const struct fc_els_spp *rspp, struct fc_els_spp *spp)
 435 {
 436         int ret;
 437
 438         mutex_lock(&ft_lport_lock);
 439         ret = ft_prli_locked(rdata, spp_len, rspp, spp);
 440         mutex_unlock(&ft_lport_lock);
 441         TFC_SESS_DBG(rdata->local_port, "port_id %x flags %x ret %x\n",
 442                      rdata->ids.port_id, rspp ? rspp->spp_flags : 0, ret);
 443         return ret;
 444 }
 445
 446 static void ft_sess_free(struct kref *kref)
 447 {
 448         struct ft_sess *sess = container_of(kref, struct ft_sess, kref);
 449
 450         target_remove_session(sess->se_sess);
 451         kfree_rcu(sess, rcu);
 452 }
 453
 454 void ft_sess_put(struct ft_sess *sess)
 455 {
 456         int sess_held = kref_read(&sess->kref);
 457
 458         BUG_ON(!sess_held);
 459         kref_put(&sess->kref, ft_sess_free);
 460 }
 461
 462 static void ft_prlo(struct fc_rport_priv *rdata)
 463 {
 464         struct ft_sess *sess;
 465         struct ft_tport *tport;
 466
 467         mutex_lock(&ft_lport_lock);
 468         tport = rcu_dereference_protected(rdata->local_port->prov[FC_TYPE_FCP],
 469                                           lockdep_is_held(&ft_lport_lock));
 470
 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         ft_close_sess(sess);            /* release from table */
 482         rdata->prli_count--;
 483         /* XXX TBD - clearing actions.  unit attn, see 4.10 */
 484 }
 485
 486 /*
 487  * Handle incoming FCP request.
 488  * Caller has verified that the frame is type FCP.
 489  */
 490 static void ft_recv(struct fc_lport *lport, struct fc_frame *fp)
 491 {
 492         struct ft_sess *sess;
 493         u32 sid = fc_frame_sid(fp);
 494
 495         TFC_SESS_DBG(lport, "recv sid %x\n", sid);
 496
 497         sess = ft_sess_get(lport, sid);
 498         if (!sess) {
 499                 TFC_SESS_DBG(lport, "sid %x sess lookup failed\n", sid);
 500                 /* TBD XXX - if FCP_CMND, send PRLO */
 501                 fc_frame_free(fp);
 502                 return;
 503         }
 504         ft_recv_req(sess, fp);  /* must do ft_sess_put() */
 505 }
 506
 507 /*
 508  * Provider ops for libfc.
 509  */
 510 struct fc4_prov ft_prov = {
 511         .prli = ft_prli,
 512         .prlo = ft_prlo,
 513         .recv = ft_recv,
 514         .module = THIS_MODULE,
 515 };