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_alloc_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         transport_deregister_session_configfs(sess->se_sess);
 291         target_sess_cmd_list_set_waiting(sess->se_sess);
 292         target_wait_for_sess_cmds(sess->se_sess);
 293         ft_sess_put(sess);
 294 }
 295
 296 /*
 297  * Delete all sessions from tport.
 298  * Caller holds ft_lport_lock.
 299  */
 300 static void ft_sess_delete_all(struct ft_tport *tport)
 301 {
 302         struct hlist_head *head;
 303         struct ft_sess *sess;
 304
 305         for (head = tport->hash;
 306              head < &tport->hash[FT_SESS_HASH_SIZE]; head++) {
 307                 hlist_for_each_entry_rcu(sess, head, hash) {
 308                         ft_sess_unhash(sess);
 309                         ft_close_sess(sess);    /* release from table */
 310                 }
 311         }
 312 }
 313
 314 /*
 315  * TCM ops for sessions.
 316  */
 317
 318 /*
 319  * Remove session and send PRLO.
 320  * This is called when the ACL is being deleted or queue depth is changing.
 321  */
 322 void ft_sess_close(struct se_session *se_sess)
 323 {
 324         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 325         u32 port_id;
 326
 327         mutex_lock(&ft_lport_lock);
 328         port_id = sess->port_id;
 329         if (port_id == -1) {
 330                 mutex_unlock(&ft_lport_lock);
 331                 return;
 332         }
 333         TFC_SESS_DBG(sess->tport->lport, "port_id %x close session\n", port_id);
 334         ft_sess_unhash(sess);
 335         mutex_unlock(&ft_lport_lock);
 336         ft_close_sess(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         u32 fcp_parm;
 366
 367         tport = ft_tport_get(rdata->local_port);
 368         if (!tport)
 369                 goto not_target;        /* not a target for this local port */
 370
 371         if (!rspp)
 372                 goto fill;
 373
 374         if (rspp->spp_flags & (FC_SPP_OPA_VAL | FC_SPP_RPA_VAL))
 375                 return FC_SPP_RESP_NO_PA;
 376
 377         /*
 378          * If both target and initiator bits are off, the SPP is invalid.
 379          */
 380         fcp_parm = ntohl(rspp->spp_params);
 381         if (!(fcp_parm & (FCP_SPPF_INIT_FCN | FCP_SPPF_TARG_FCN)))
 382                 return FC_SPP_RESP_INVL;
 383
 384         /*
 385          * Create session (image pair) only if requested by
 386          * EST_IMG_PAIR flag and if the requestor is an initiator.
 387          */
 388         if (rspp->spp_flags & FC_SPP_EST_IMG_PAIR) {
 389                 spp->spp_flags |= FC_SPP_EST_IMG_PAIR;
 390                 if (!(fcp_parm & FCP_SPPF_INIT_FCN))
 391                         return FC_SPP_RESP_CONF;
 392                 sess = ft_sess_create(tport, rdata->ids.port_id, rdata);
 393                 if (IS_ERR(sess)) {
 394                         if (PTR_ERR(sess) == -EACCES) {
 395                                 spp->spp_flags &= ~FC_SPP_EST_IMG_PAIR;
 396                                 return FC_SPP_RESP_CONF;
 397                         } else
 398                                 return FC_SPP_RESP_RES;
 399                 }
 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          */
 412 fill:
 413         fcp_parm = ntohl(spp->spp_params);
 414         fcp_parm &= ~FCP_SPPF_RETRY;
 415         spp->spp_params = htonl(fcp_parm | FCP_SPPF_TARG_FCN);
 416         return FC_SPP_RESP_ACK;
 417
 418 not_target:
 419         fcp_parm = ntohl(spp->spp_params);
 420         fcp_parm &= ~FCP_SPPF_TARG_FCN;
 421         spp->spp_params = htonl(fcp_parm);
 422         return 0;
 423 }
 424
 425 /**
 426  * tcm_fcp_prli() - Handle incoming or outgoing PRLI for the FCP target
 427  * @rdata: remote port private
 428  * @spp_len: service parameter page length
 429  * @rspp: received service parameter page (NULL for outgoing PRLI)
 430  * @spp: response service parameter page
 431  *
 432  * Returns spp response code.
 433  */
 434 static int ft_prli(struct fc_rport_priv *rdata, u32 spp_len,
 435                    const struct fc_els_spp *rspp, struct fc_els_spp *spp)
 436 {
 437         int ret;
 438
 439         mutex_lock(&ft_lport_lock);
 440         ret = ft_prli_locked(rdata, spp_len, rspp, spp);
 441         mutex_unlock(&ft_lport_lock);
 442         TFC_SESS_DBG(rdata->local_port, "port_id %x flags %x ret %x\n",
 443                      rdata->ids.port_id, rspp ? rspp->spp_flags : 0, ret);
 444         return ret;
 445 }
 446
 447 static void ft_sess_free(struct kref *kref)
 448 {
 449         struct ft_sess *sess = container_of(kref, struct ft_sess, kref);
 450
 451         transport_deregister_session(sess->se_sess);
 452         kfree_rcu(sess, rcu);
 453 }
 454
 455 void ft_sess_put(struct ft_sess *sess)
 456 {
 457         int sess_held = atomic_read(&sess->kref.refcount);
 458
 459         BUG_ON(!sess_held);
 460         kref_put(&sess->kref, ft_sess_free);
 461 }
 462
 463 static void ft_prlo(struct fc_rport_priv *rdata)
 464 {
 465         struct ft_sess *sess;
 466         struct ft_tport *tport;
 467
 468         mutex_lock(&ft_lport_lock);
 469         tport = rcu_dereference_protected(rdata->local_port->prov[FC_TYPE_FCP],
 470                                           lockdep_is_held(&ft_lport_lock));
 471
 472         if (!tport) {
 473                 mutex_unlock(&ft_lport_lock);
 474                 return;
 475         }
 476         sess = ft_sess_delete(tport, rdata->ids.port_id);
 477         if (!sess) {
 478                 mutex_unlock(&ft_lport_lock);
 479                 return;
 480         }
 481         mutex_unlock(&ft_lport_lock);
 482         ft_close_sess(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         TFC_SESS_DBG(lport, "recv sid %x\n", sid);
 497
 498         sess = ft_sess_get(lport, sid);
 499         if (!sess) {
 500                 TFC_SESS_DBG(lport, "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 };