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