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 #include <target/configfs_macros.h>
  40
  41 #include "tcm_fc.h"
  42
  43 static void ft_sess_delete_all(struct ft_tport *);
  44
  45 /*
  46  * Lookup or allocate target local port.
  47  * Caller holds ft_lport_lock.
  48  */
  49 static struct ft_tport *ft_tport_get(struct fc_lport *lport)
  50 {
  51         struct ft_tpg *tpg;
  52         struct ft_tport *tport;
  53         int i;
  54
  55         tport = rcu_dereference_protected(lport->prov[FC_TYPE_FCP],
  56                                           lockdep_is_held(&ft_lport_lock));
  57         if (tport && tport->tpg)
  58                 return tport;
  59
  60         tpg = ft_lport_find_tpg(lport);
  61         if (!tpg)
  62                 return NULL;
  63
  64         if (tport) {
  65                 tport->tpg = tpg;
  66                 tpg->tport = tport;
  67                 return tport;
  68         }
  69
  70         tport = kzalloc(sizeof(*tport), GFP_KERNEL);
  71         if (!tport)
  72                 return NULL;
  73
  74         tport->lport = lport;
  75         tport->tpg = tpg;
  76         tpg->tport = tport;
  77         for (i = 0; i < FT_SESS_HASH_SIZE; i++)
  78                 INIT_HLIST_HEAD(&tport->hash[i]);
  79
  80         rcu_assign_pointer(lport->prov[FC_TYPE_FCP], tport);
  81         return tport;
  82 }
  83
  84 /*
  85  * Delete a target local port.
  86  * Caller holds ft_lport_lock.
  87  */
  88 static void ft_tport_delete(struct ft_tport *tport)
  89 {
  90         struct fc_lport *lport;
  91         struct ft_tpg *tpg;
  92
  93         ft_sess_delete_all(tport);
  94         lport = tport->lport;
  95         BUG_ON(tport != lport->prov[FC_TYPE_FCP]);
  96         RCU_INIT_POINTER(lport->prov[FC_TYPE_FCP], NULL);
  97
  98         tpg = tport->tpg;
  99         if (tpg) {
 100                 tpg->tport = NULL;
 101                 tport->tpg = NULL;
 102         }
 103         kfree_rcu(tport, rcu);
 104 }
 105
 106 /*
 107  * Add local port.
 108  * Called thru fc_lport_iterate().
 109  */
 110 void ft_lport_add(struct fc_lport *lport, void *arg)
 111 {
 112         mutex_lock(&ft_lport_lock);
 113         ft_tport_get(lport);
 114         mutex_unlock(&ft_lport_lock);
 115 }
 116
 117 /*
 118  * Delete local port.
 119  * Called thru fc_lport_iterate().
 120  */
 121 void ft_lport_del(struct fc_lport *lport, void *arg)
 122 {
 123         struct ft_tport *tport;
 124
 125         mutex_lock(&ft_lport_lock);
 126         tport = lport->prov[FC_TYPE_FCP];
 127         if (tport)
 128                 ft_tport_delete(tport);
 129         mutex_unlock(&ft_lport_lock);
 130 }
 131
 132 /*
 133  * Notification of local port change from libfc.
 134  * Create or delete local port and associated tport.
 135  */
 136 int ft_lport_notify(struct notifier_block *nb, unsigned long event, void *arg)
 137 {
 138         struct fc_lport *lport = arg;
 139
 140         switch (event) {
 141         case FC_LPORT_EV_ADD:
 142                 ft_lport_add(lport, NULL);
 143                 break;
 144         case FC_LPORT_EV_DEL:
 145                 ft_lport_del(lport, NULL);
 146                 break;
 147         }
 148         return NOTIFY_DONE;
 149 }
 150
 151 /*
 152  * Hash function for FC_IDs.
 153  */
 154 static u32 ft_sess_hash(u32 port_id)
 155 {
 156         return hash_32(port_id, FT_SESS_HASH_BITS);
 157 }
 158
 159 /*
 160  * Find session in local port.
 161  * Sessions and hash lists are RCU-protected.
 162  * A reference is taken which must be eventually freed.
 163  */
 164 static struct ft_sess *ft_sess_get(struct fc_lport *lport, u32 port_id)
 165 {
 166         struct ft_tport *tport;
 167         struct hlist_head *head;
 168         struct ft_sess *sess;
 169
 170         rcu_read_lock();
 171         tport = rcu_dereference(lport->prov[FC_TYPE_FCP]);
 172         if (!tport)
 173                 goto out;
 174
 175         head = &tport->hash[ft_sess_hash(port_id)];
 176         hlist_for_each_entry_rcu(sess, head, hash) {
 177                 if (sess->port_id == port_id) {
 178                         kref_get(&sess->kref);
 179                         rcu_read_unlock();
 180                         pr_debug("port_id %x found %p\n", port_id, sess);
 181                         return sess;
 182                 }
 183         }
 184 out:
 185         rcu_read_unlock();
 186         pr_debug("port_id %x not found\n", port_id);
 187         return NULL;
 188 }
 189
 190 /*
 191  * Allocate session and enter it in the hash for the local port.
 192  * Caller holds ft_lport_lock.
 193  */
 194 static struct ft_sess *ft_sess_create(struct ft_tport *tport, u32 port_id,
 195                                       struct ft_node_acl *acl)
 196 {
 197         struct ft_sess *sess;
 198         struct hlist_head *head;
 199
 200         head = &tport->hash[ft_sess_hash(port_id)];
 201         hlist_for_each_entry_rcu(sess, head, hash)
 202                 if (sess->port_id == port_id)
 203                         return sess;
 204
 205         sess = kzalloc(sizeof(*sess), GFP_KERNEL);
 206         if (!sess)
 207                 return NULL;
 208
 209         sess->se_sess = transport_init_session_tags(TCM_FC_DEFAULT_TAGS,
 210                                                     sizeof(struct ft_cmd),
 211                                                     TARGET_PROT_NORMAL);
 212         if (IS_ERR(sess->se_sess)) {
 213                 kfree(sess);
 214                 return NULL;
 215         }
 216         sess->se_sess->se_node_acl = &acl->se_node_acl;
 217         sess->tport = tport;
 218         sess->port_id = port_id;
 219         kref_init(&sess->kref); /* ref for table entry */
 220         hlist_add_head_rcu(&sess->hash, head);
 221         tport->sess_count++;
 222
 223         pr_debug("port_id %x sess %p\n", port_id, sess);
 224
 225         transport_register_session(&tport->tpg->se_tpg, &acl->se_node_acl,
 226                                    sess->se_sess, sess);
 227         return sess;
 228 }
 229
 230 /*
 231  * Unhash the session.
 232  * Caller holds ft_lport_lock.
 233  */
 234 static void ft_sess_unhash(struct ft_sess *sess)
 235 {
 236         struct ft_tport *tport = sess->tport;
 237
 238         hlist_del_rcu(&sess->hash);
 239         BUG_ON(!tport->sess_count);
 240         tport->sess_count--;
 241         sess->port_id = -1;
 242         sess->params = 0;
 243 }
 244
 245 /*
 246  * Delete session from hash.
 247  * Caller holds ft_lport_lock.
 248  */
 249 static struct ft_sess *ft_sess_delete(struct ft_tport *tport, u32 port_id)
 250 {
 251         struct hlist_head *head;
 252         struct ft_sess *sess;
 253
 254         head = &tport->hash[ft_sess_hash(port_id)];
 255         hlist_for_each_entry_rcu(sess, head, hash) {
 256                 if (sess->port_id == port_id) {
 257                         ft_sess_unhash(sess);
 258                         return sess;
 259                 }
 260         }
 261         return NULL;
 262 }
 263
 264 /*
 265  * Delete all sessions from tport.
 266  * Caller holds ft_lport_lock.
 267  */
 268 static void ft_sess_delete_all(struct ft_tport *tport)
 269 {
 270         struct hlist_head *head;
 271         struct ft_sess *sess;
 272
 273         for (head = tport->hash;
 274              head < &tport->hash[FT_SESS_HASH_SIZE]; head++) {
 275                 hlist_for_each_entry_rcu(sess, head, hash) {
 276                         ft_sess_unhash(sess);
 277                         transport_deregister_session_configfs(sess->se_sess);
 278                         ft_sess_put(sess);      /* release from table */
 279                 }
 280         }
 281 }
 282
 283 /*
 284  * TCM ops for sessions.
 285  */
 286
 287 /*
 288  * Determine whether session is allowed to be shutdown in the current context.
 289  * Returns non-zero if the session should be shutdown.
 290  */
 291 int ft_sess_shutdown(struct se_session *se_sess)
 292 {
 293         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 294
 295         pr_debug("port_id %x\n", sess->port_id);
 296         return 1;
 297 }
 298
 299 /*
 300  * Remove session and send PRLO.
 301  * This is called when the ACL is being deleted or queue depth is changing.
 302  */
 303 void ft_sess_close(struct se_session *se_sess)
 304 {
 305         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 306         u32 port_id;
 307
 308         mutex_lock(&ft_lport_lock);
 309         port_id = sess->port_id;
 310         if (port_id == -1) {
 311                 mutex_unlock(&ft_lport_lock);
 312                 return;
 313         }
 314         pr_debug("port_id %x\n", port_id);
 315         ft_sess_unhash(sess);
 316         mutex_unlock(&ft_lport_lock);
 317         transport_deregister_session_configfs(se_sess);
 318         ft_sess_put(sess);
 319         /* XXX Send LOGO or PRLO */
 320         synchronize_rcu();              /* let transport deregister happen */
 321 }
 322
 323 u32 ft_sess_get_index(struct se_session *se_sess)
 324 {
 325         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 326
 327         return sess->port_id;   /* XXX TBD probably not what is needed */
 328 }
 329
 330 u32 ft_sess_get_port_name(struct se_session *se_sess,
 331                           unsigned char *buf, u32 len)
 332 {
 333         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 334
 335         return ft_format_wwn(buf, len, sess->port_name);
 336 }
 337
 338 /*
 339  * libfc ops involving sessions.
 340  */
 341
 342 static int ft_prli_locked(struct fc_rport_priv *rdata, u32 spp_len,
 343                           const struct fc_els_spp *rspp, struct fc_els_spp *spp)
 344 {
 345         struct ft_tport *tport;
 346         struct ft_sess *sess;
 347         struct ft_node_acl *acl;
 348         u32 fcp_parm;
 349
 350         tport = ft_tport_get(rdata->local_port);
 351         if (!tport)
 352                 goto not_target;        /* not a target for this local port */
 353
 354         acl = ft_acl_get(tport->tpg, rdata);
 355         if (!acl)
 356                 goto not_target;        /* no target for this remote */
 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, acl);
 380                 if (!sess)
 381                         return FC_SPP_RESP_RES;
 382                 if (!sess->params)
 383                         rdata->prli_count++;
 384                 sess->params = fcp_parm;
 385                 sess->port_name = rdata->ids.port_name;
 386                 sess->max_frame = rdata->maxframe_size;
 387
 388                 /* XXX TBD - clearing actions.  unit attn, see 4.10 */
 389         }
 390
 391         /*
 392          * OR in our service parameters with other provider (initiator), if any.
 393          */
 394 fill:
 395         fcp_parm = ntohl(spp->spp_params);
 396         fcp_parm &= ~FCP_SPPF_RETRY;
 397         spp->spp_params = htonl(fcp_parm | FCP_SPPF_TARG_FCN);
 398         return FC_SPP_RESP_ACK;
 399
 400 not_target:
 401         fcp_parm = ntohl(spp->spp_params);
 402         fcp_parm &= ~FCP_SPPF_TARG_FCN;
 403         spp->spp_params = htonl(fcp_parm);
 404         return 0;
 405 }
 406
 407 /**
 408  * tcm_fcp_prli() - Handle incoming or outgoing PRLI for the FCP target
 409  * @rdata: remote port private
 410  * @spp_len: service parameter page length
 411  * @rspp: received service parameter page (NULL for outgoing PRLI)
 412  * @spp: response service parameter page
 413  *
 414  * Returns spp response code.
 415  */
 416 static int ft_prli(struct fc_rport_priv *rdata, u32 spp_len,
 417                    const struct fc_els_spp *rspp, struct fc_els_spp *spp)
 418 {
 419         int ret;
 420
 421         mutex_lock(&ft_lport_lock);
 422         ret = ft_prli_locked(rdata, spp_len, rspp, spp);
 423         mutex_unlock(&ft_lport_lock);
 424         pr_debug("port_id %x flags %x ret %x\n",
 425                rdata->ids.port_id, rspp ? rspp->spp_flags : 0, ret);
 426         return ret;
 427 }
 428
 429 static void ft_sess_free(struct kref *kref)
 430 {
 431         struct ft_sess *sess = container_of(kref, struct ft_sess, kref);
 432
 433         transport_deregister_session(sess->se_sess);
 434         kfree_rcu(sess, rcu);
 435 }
 436
 437 void ft_sess_put(struct ft_sess *sess)
 438 {
 439         int sess_held = atomic_read(&sess->kref.refcount);
 440
 441         BUG_ON(!sess_held);
 442         kref_put(&sess->kref, ft_sess_free);
 443 }
 444
 445 static void ft_prlo(struct fc_rport_priv *rdata)
 446 {
 447         struct ft_sess *sess;
 448         struct ft_tport *tport;
 449
 450         mutex_lock(&ft_lport_lock);
 451         tport = rcu_dereference_protected(rdata->local_port->prov[FC_TYPE_FCP],
 452                                           lockdep_is_held(&ft_lport_lock));
 453
 454         if (!tport) {
 455                 mutex_unlock(&ft_lport_lock);
 456                 return;
 457         }
 458         sess = ft_sess_delete(tport, rdata->ids.port_id);
 459         if (!sess) {
 460                 mutex_unlock(&ft_lport_lock);
 461                 return;
 462         }
 463         mutex_unlock(&ft_lport_lock);
 464         transport_deregister_session_configfs(sess->se_sess);
 465         ft_sess_put(sess);              /* release from table */
 466         rdata->prli_count--;
 467         /* XXX TBD - clearing actions.  unit attn, see 4.10 */
 468 }
 469
 470 /*
 471  * Handle incoming FCP request.
 472  * Caller has verified that the frame is type FCP.
 473  */
 474 static void ft_recv(struct fc_lport *lport, struct fc_frame *fp)
 475 {
 476         struct ft_sess *sess;
 477         u32 sid = fc_frame_sid(fp);
 478
 479         pr_debug("sid %x\n", sid);
 480
 481         sess = ft_sess_get(lport, sid);
 482         if (!sess) {
 483                 pr_debug("sid %x sess lookup failed\n", sid);
 484                 /* TBD XXX - if FCP_CMND, send PRLO */
 485                 fc_frame_free(fp);
 486                 return;
 487         }
 488         ft_recv_req(sess, fp);  /* must do ft_sess_put() */
 489 }
 490
 491 /*
 492  * Provider ops for libfc.
 493  */
 494 struct fc4_prov ft_prov = {
 495         .prli = ft_prli,
 496         .prlo = ft_prlo,
 497         .recv = ft_recv,
 498         .module = THIS_MODULE,
 499 };