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 <generated/utsrelease.h>
  23 #include <linux/utsname.h>
  24 #include <linux/init.h>
  25 #include <linux/slab.h>
  26 #include <linux/kthread.h>
  27 #include <linux/types.h>
  28 #include <linux/string.h>
  29 #include <linux/configfs.h>
  30 #include <linux/ctype.h>
  31 #include <linux/hash.h>
  32 #include <linux/rcupdate.h>
  33 #include <linux/rculist.h>
  34 #include <linux/kref.h>
  35 #include <asm/unaligned.h>
  36 #include <scsi/scsi.h>
  37 #include <scsi/scsi_host.h>
  38 #include <scsi/scsi_device.h>
  39 #include <scsi/scsi_cmnd.h>
  40 #include <scsi/libfc.h>
  41
  42 #include <target/target_core_base.h>
  43 #include <target/target_core_fabric.h>
  44 #include <target/target_core_configfs.h>
  45 #include <target/configfs_macros.h>
  46
  47 #include "tcm_fc.h"
  48
  49 static void ft_sess_delete_all(struct ft_tport *);
  50
  51 /*
  52  * Lookup or allocate target local port.
  53  * Caller holds ft_lport_lock.
  54  */
  55 static struct ft_tport *ft_tport_create(struct fc_lport *lport)
  56 {
  57         struct ft_tpg *tpg;
  58         struct ft_tport *tport;
  59         int i;
  60
  61         tport = rcu_dereference(lport->prov[FC_TYPE_FCP]);
  62         if (tport && tport->tpg)
  63                 return tport;
  64
  65         tpg = ft_lport_find_tpg(lport);
  66         if (!tpg)
  67                 return NULL;
  68
  69         if (tport) {
  70                 tport->tpg = tpg;
  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         BUG_ON(tport != lport->prov[FC_TYPE_FCP]);
 100         rcu_assign_pointer(lport->prov[FC_TYPE_FCP], NULL);
 101
 102         tpg = tport->tpg;
 103         if (tpg) {
 104                 tpg->tport = NULL;
 105                 tport->tpg = NULL;
 106         }
 107         kfree_rcu(tport, rcu);
 108 }
 109
 110 /*
 111  * Add local port.
 112  * Called thru fc_lport_iterate().
 113  */
 114 void ft_lport_add(struct fc_lport *lport, void *arg)
 115 {
 116         mutex_lock(&ft_lport_lock);
 117         ft_tport_create(lport);
 118         mutex_unlock(&ft_lport_lock);
 119 }
 120
 121 /*
 122  * Delete local port.
 123  * Called thru fc_lport_iterate().
 124  */
 125 void ft_lport_del(struct fc_lport *lport, void *arg)
 126 {
 127         struct ft_tport *tport;
 128
 129         mutex_lock(&ft_lport_lock);
 130         tport = lport->prov[FC_TYPE_FCP];
 131         if (tport)
 132                 ft_tport_delete(tport);
 133         mutex_unlock(&ft_lport_lock);
 134 }
 135
 136 /*
 137  * Notification of local port change from libfc.
 138  * Create or delete local port and associated tport.
 139  */
 140 int ft_lport_notify(struct notifier_block *nb, unsigned long event, void *arg)
 141 {
 142         struct fc_lport *lport = arg;
 143
 144         switch (event) {
 145         case FC_LPORT_EV_ADD:
 146                 ft_lport_add(lport, NULL);
 147                 break;
 148         case FC_LPORT_EV_DEL:
 149                 ft_lport_del(lport, NULL);
 150                 break;
 151         }
 152         return NOTIFY_DONE;
 153 }
 154
 155 /*
 156  * Hash function for FC_IDs.
 157  */
 158 static u32 ft_sess_hash(u32 port_id)
 159 {
 160         return hash_32(port_id, FT_SESS_HASH_BITS);
 161 }
 162
 163 /*
 164  * Find session in local port.
 165  * Sessions and hash lists are RCU-protected.
 166  * A reference is taken which must be eventually freed.
 167  */
 168 static struct ft_sess *ft_sess_get(struct fc_lport *lport, u32 port_id)
 169 {
 170         struct ft_tport *tport;
 171         struct hlist_head *head;
 172         struct hlist_node *pos;
 173         struct ft_sess *sess;
 174
 175         rcu_read_lock();
 176         tport = rcu_dereference(lport->prov[FC_TYPE_FCP]);
 177         if (!tport)
 178                 goto out;
 179
 180         head = &tport->hash[ft_sess_hash(port_id)];
 181         hlist_for_each_entry_rcu(sess, pos, head, hash) {
 182                 if (sess->port_id == port_id) {
 183                         kref_get(&sess->kref);
 184                         rcu_read_unlock();
 185                         pr_debug("port_id %x found %p\n", port_id, sess);
 186                         return sess;
 187                 }
 188         }
 189 out:
 190         rcu_read_unlock();
 191         pr_debug("port_id %x not found\n", port_id);
 192         return NULL;
 193 }
 194
 195 /*
 196  * Allocate session and enter it in the hash for the local port.
 197  * Caller holds ft_lport_lock.
 198  */
 199 static struct ft_sess *ft_sess_create(struct ft_tport *tport, u32 port_id,
 200                                       struct ft_node_acl *acl)
 201 {
 202         struct ft_sess *sess;
 203         struct hlist_head *head;
 204         struct hlist_node *pos;
 205
 206         head = &tport->hash[ft_sess_hash(port_id)];
 207         hlist_for_each_entry_rcu(sess, pos, head, hash)
 208                 if (sess->port_id == port_id)
 209                         return sess;
 210
 211         sess = kzalloc(sizeof(*sess), GFP_KERNEL);
 212         if (!sess)
 213                 return NULL;
 214
 215         sess->se_sess = transport_init_session();
 216         if (IS_ERR(sess->se_sess)) {
 217                 kfree(sess);
 218                 return NULL;
 219         }
 220         sess->se_sess->se_node_acl = &acl->se_node_acl;
 221         sess->tport = tport;
 222         sess->port_id = port_id;
 223         kref_init(&sess->kref); /* ref for table entry */
 224         hlist_add_head_rcu(&sess->hash, head);
 225         tport->sess_count++;
 226
 227         pr_debug("port_id %x sess %p\n", port_id, sess);
 228
 229         transport_register_session(&tport->tpg->se_tpg, &acl->se_node_acl,
 230                                    sess->se_sess, sess);
 231         return sess;
 232 }
 233
 234 /*
 235  * Unhash the session.
 236  * Caller holds ft_lport_lock.
 237  */
 238 static void ft_sess_unhash(struct ft_sess *sess)
 239 {
 240         struct ft_tport *tport = sess->tport;
 241
 242         hlist_del_rcu(&sess->hash);
 243         BUG_ON(!tport->sess_count);
 244         tport->sess_count--;
 245         sess->port_id = -1;
 246         sess->params = 0;
 247 }
 248
 249 /*
 250  * Delete session from hash.
 251  * Caller holds ft_lport_lock.
 252  */
 253 static struct ft_sess *ft_sess_delete(struct ft_tport *tport, u32 port_id)
 254 {
 255         struct hlist_head *head;
 256         struct hlist_node *pos;
 257         struct ft_sess *sess;
 258
 259         head = &tport->hash[ft_sess_hash(port_id)];
 260         hlist_for_each_entry_rcu(sess, pos, head, hash) {
 261                 if (sess->port_id == port_id) {
 262                         ft_sess_unhash(sess);
 263                         return sess;
 264                 }
 265         }
 266         return NULL;
 267 }
 268
 269 /*
 270  * Delete all sessions from tport.
 271  * Caller holds ft_lport_lock.
 272  */
 273 static void ft_sess_delete_all(struct ft_tport *tport)
 274 {
 275         struct hlist_head *head;
 276         struct hlist_node *pos;
 277         struct ft_sess *sess;
 278
 279         for (head = tport->hash;
 280              head < &tport->hash[FT_SESS_HASH_SIZE]; head++) {
 281                 hlist_for_each_entry_rcu(sess, pos, head, hash) {
 282                         ft_sess_unhash(sess);
 283                         transport_deregister_session_configfs(sess->se_sess);
 284                         ft_sess_put(sess);      /* release from table */
 285                 }
 286         }
 287 }
 288
 289 /*
 290  * TCM ops for sessions.
 291  */
 292
 293 /*
 294  * Determine whether session is allowed to be shutdown in the current context.
 295  * Returns non-zero if the session should be shutdown.
 296  */
 297 int ft_sess_shutdown(struct se_session *se_sess)
 298 {
 299         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 300
 301         pr_debug("port_id %x\n", sess->port_id);
 302         return 1;
 303 }
 304
 305 /*
 306  * Remove session and send PRLO.
 307  * This is called when the ACL is being deleted or queue depth is changing.
 308  */
 309 void ft_sess_close(struct se_session *se_sess)
 310 {
 311         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 312         u32 port_id;
 313
 314         mutex_lock(&ft_lport_lock);
 315         port_id = sess->port_id;
 316         if (port_id == -1) {
 317                 mutex_unlock(&ft_lport_lock);
 318                 return;
 319         }
 320         pr_debug("port_id %x\n", port_id);
 321         ft_sess_unhash(sess);
 322         mutex_unlock(&ft_lport_lock);
 323         transport_deregister_session_configfs(se_sess);
 324         ft_sess_put(sess);
 325         /* XXX Send LOGO or PRLO */
 326         synchronize_rcu();              /* let transport deregister happen */
 327 }
 328
 329 u32 ft_sess_get_index(struct se_session *se_sess)
 330 {
 331         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 332
 333         return sess->port_id;   /* XXX TBD probably not what is needed */
 334 }
 335
 336 u32 ft_sess_get_port_name(struct se_session *se_sess,
 337                           unsigned char *buf, u32 len)
 338 {
 339         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 340
 341         return ft_format_wwn(buf, len, sess->port_name);
 342 }
 343
 344 /*
 345  * libfc ops involving sessions.
 346  */
 347
 348 static int ft_prli_locked(struct fc_rport_priv *rdata, u32 spp_len,
 349                           const struct fc_els_spp *rspp, struct fc_els_spp *spp)
 350 {
 351         struct ft_tport *tport;
 352         struct ft_sess *sess;
 353         struct ft_node_acl *acl;
 354         u32 fcp_parm;
 355
 356         tport = ft_tport_create(rdata->local_port);
 357         if (!tport)
 358                 return 0;       /* not a target for this local port */
 359
 360         acl = ft_acl_get(tport->tpg, rdata);
 361         if (!acl)
 362                 return 0;
 363
 364         if (!rspp)
 365                 goto fill;
 366
 367         if (rspp->spp_flags & (FC_SPP_OPA_VAL | FC_SPP_RPA_VAL))
 368                 return FC_SPP_RESP_NO_PA;
 369
 370         /*
 371          * If both target and initiator bits are off, the SPP is invalid.
 372          */
 373         fcp_parm = ntohl(rspp->spp_params);
 374         if (!(fcp_parm & (FCP_SPPF_INIT_FCN | FCP_SPPF_TARG_FCN)))
 375                 return FC_SPP_RESP_INVL;
 376
 377         /*
 378          * Create session (image pair) only if requested by
 379          * EST_IMG_PAIR flag and if the requestor is an initiator.
 380          */
 381         if (rspp->spp_flags & FC_SPP_EST_IMG_PAIR) {
 382                 spp->spp_flags |= FC_SPP_EST_IMG_PAIR;
 383                 if (!(fcp_parm & FCP_SPPF_INIT_FCN))
 384                         return FC_SPP_RESP_CONF;
 385                 sess = ft_sess_create(tport, rdata->ids.port_id, acl);
 386                 if (!sess)
 387                         return FC_SPP_RESP_RES;
 388                 if (!sess->params)
 389                         rdata->prli_count++;
 390                 sess->params = fcp_parm;
 391                 sess->port_name = rdata->ids.port_name;
 392                 sess->max_frame = rdata->maxframe_size;
 393
 394                 /* XXX TBD - clearing actions.  unit attn, see 4.10 */
 395         }
 396
 397         /*
 398          * OR in our service parameters with other provider (initiator), if any.
 399          * TBD XXX - indicate RETRY capability?
 400          */
 401 fill:
 402         fcp_parm = ntohl(spp->spp_params);
 403         spp->spp_params = htonl(fcp_parm | FCP_SPPF_TARG_FCN);
 404         return FC_SPP_RESP_ACK;
 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_rcu_free(struct rcu_head *rcu)
 430 {
 431         struct ft_sess *sess = container_of(rcu, struct ft_sess, rcu);
 432
 433         transport_deregister_session(sess->se_sess);
 434         kfree(sess);
 435 }
 436
 437 static void ft_sess_free(struct kref *kref)
 438 {
 439         struct ft_sess *sess = container_of(kref, struct ft_sess, kref);
 440
 441         call_rcu(&sess->rcu, ft_sess_rcu_free);
 442 }
 443
 444 void ft_sess_put(struct ft_sess *sess)
 445 {
 446         int sess_held = atomic_read(&sess->kref.refcount);
 447
 448         BUG_ON(!sess_held);
 449         kref_put(&sess->kref, ft_sess_free);
 450 }
 451
 452 static void ft_prlo(struct fc_rport_priv *rdata)
 453 {
 454         struct ft_sess *sess;
 455         struct ft_tport *tport;
 456
 457         mutex_lock(&ft_lport_lock);
 458         tport = rcu_dereference(rdata->local_port->prov[FC_TYPE_FCP]);
 459         if (!tport) {
 460                 mutex_unlock(&ft_lport_lock);
 461                 return;
 462         }
 463         sess = ft_sess_delete(tport, rdata->ids.port_id);
 464         if (!sess) {
 465                 mutex_unlock(&ft_lport_lock);
 466                 return;
 467         }
 468         mutex_unlock(&ft_lport_lock);
 469         transport_deregister_session_configfs(sess->se_sess);
 470         ft_sess_put(sess);              /* release from table */
 471         rdata->prli_count--;
 472         /* XXX TBD - clearing actions.  unit attn, see 4.10 */
 473 }
 474
 475 /*
 476  * Handle incoming FCP request.
 477  * Caller has verified that the frame is type FCP.
 478  */
 479 static void ft_recv(struct fc_lport *lport, struct fc_frame *fp)
 480 {
 481         struct ft_sess *sess;
 482         u32 sid = fc_frame_sid(fp);
 483
 484         pr_debug("sid %x\n", sid);
 485
 486         sess = ft_sess_get(lport, sid);
 487         if (!sess) {
 488                 pr_debug("sid %x sess lookup failed\n", sid);
 489                 /* TBD XXX - if FCP_CMND, send PRLO */
 490                 fc_frame_free(fp);
 491                 return;
 492         }
 493         ft_recv_req(sess, fp);  /* must do ft_sess_put() */
 494 }
 495
 496 /*
 497  * Provider ops for libfc.
 498  */
 499 struct fc4_prov ft_prov = {
 500         .prli = ft_prli,
 501         .prlo = ft_prlo,
 502         .recv = ft_recv,
 503         .module = THIS_MODULE,
 504 };