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         BUG_ON(tport != lport->prov[FC_TYPE_FCP]);
  95         RCU_INIT_POINTER(lport->prov[FC_TYPE_FCP], NULL);
  96
  97         tpg = tport->tpg;
  98         if (tpg) {
  99                 tpg->tport = NULL;
 100                 tport->tpg = NULL;
 101         }
 102         kfree_rcu(tport, rcu);
 103 }
 104
 105 /*
 106  * Add local port.
 107  * Called thru fc_lport_iterate().
 108  */
 109 void ft_lport_add(struct fc_lport *lport, void *arg)
 110 {
 111         mutex_lock(&ft_lport_lock);
 112         ft_tport_get(lport);
 113         mutex_unlock(&ft_lport_lock);
 114 }
 115
 116 /*
 117  * Delete local port.
 118  * Called thru fc_lport_iterate().
 119  */
 120 void ft_lport_del(struct fc_lport *lport, void *arg)
 121 {
 122         struct ft_tport *tport;
 123
 124         mutex_lock(&ft_lport_lock);
 125         tport = lport->prov[FC_TYPE_FCP];
 126         if (tport)
 127                 ft_tport_delete(tport);
 128         mutex_unlock(&ft_lport_lock);
 129 }
 130
 131 /*
 132  * Notification of local port change from libfc.
 133  * Create or delete local port and associated tport.
 134  */
 135 int ft_lport_notify(struct notifier_block *nb, unsigned long event, void *arg)
 136 {
 137         struct fc_lport *lport = arg;
 138
 139         switch (event) {
 140         case FC_LPORT_EV_ADD:
 141                 ft_lport_add(lport, NULL);
 142                 break;
 143         case FC_LPORT_EV_DEL:
 144                 ft_lport_del(lport, NULL);
 145                 break;
 146         }
 147         return NOTIFY_DONE;
 148 }
 149
 150 /*
 151  * Hash function for FC_IDs.
 152  */
 153 static u32 ft_sess_hash(u32 port_id)
 154 {
 155         return hash_32(port_id, FT_SESS_HASH_BITS);
 156 }
 157
 158 /*
 159  * Find session in local port.
 160  * Sessions and hash lists are RCU-protected.
 161  * A reference is taken which must be eventually freed.
 162  */
 163 static struct ft_sess *ft_sess_get(struct fc_lport *lport, u32 port_id)
 164 {
 165         struct ft_tport *tport;
 166         struct hlist_head *head;
 167         struct ft_sess *sess;
 168
 169         rcu_read_lock();
 170         tport = rcu_dereference(lport->prov[FC_TYPE_FCP]);
 171         if (!tport)
 172                 goto out;
 173
 174         head = &tport->hash[ft_sess_hash(port_id)];
 175         hlist_for_each_entry_rcu(sess, head, hash) {
 176                 if (sess->port_id == port_id) {
 177                         kref_get(&sess->kref);
 178                         rcu_read_unlock();
 179                         pr_debug("port_id %x found %p\n", port_id, sess);
 180                         return sess;
 181                 }
 182         }
 183 out:
 184         rcu_read_unlock();
 185         pr_debug("port_id %x not found\n", port_id);
 186         return NULL;
 187 }
 188
 189 /*
 190  * Allocate session and enter it in the hash for the local port.
 191  * Caller holds ft_lport_lock.
 192  */
 193 static struct ft_sess *ft_sess_create(struct ft_tport *tport, u32 port_id,
 194                                       struct ft_node_acl *acl)
 195 {
 196         struct ft_sess *sess;
 197         struct hlist_head *head;
 198
 199         head = &tport->hash[ft_sess_hash(port_id)];
 200         hlist_for_each_entry_rcu(sess, head, hash)
 201                 if (sess->port_id == port_id)
 202                         return sess;
 203
 204         sess = kzalloc(sizeof(*sess), GFP_KERNEL);
 205         if (!sess)
 206                 return NULL;
 207
 208         sess->se_sess = transport_init_session_tags(TCM_FC_DEFAULT_TAGS,
 209                                                     sizeof(struct ft_cmd),
 210                                                     TARGET_PROT_NORMAL);
 211         if (IS_ERR(sess->se_sess)) {
 212                 kfree(sess);
 213                 return NULL;
 214         }
 215         sess->se_sess->se_node_acl = &acl->se_node_acl;
 216         sess->tport = tport;
 217         sess->port_id = port_id;
 218         kref_init(&sess->kref); /* ref for table entry */
 219         hlist_add_head_rcu(&sess->hash, head);
 220         tport->sess_count++;
 221
 222         pr_debug("port_id %x sess %p\n", port_id, sess);
 223
 224         transport_register_session(&tport->tpg->se_tpg, &acl->se_node_acl,
 225                                    sess->se_sess, sess);
 226         return sess;
 227 }
 228
 229 /*
 230  * Unhash the session.
 231  * Caller holds ft_lport_lock.
 232  */
 233 static void ft_sess_unhash(struct ft_sess *sess)
 234 {
 235         struct ft_tport *tport = sess->tport;
 236
 237         hlist_del_rcu(&sess->hash);
 238         BUG_ON(!tport->sess_count);
 239         tport->sess_count--;
 240         sess->port_id = -1;
 241         sess->params = 0;
 242 }
 243
 244 /*
 245  * Delete session from hash.
 246  * Caller holds ft_lport_lock.
 247  */
 248 static struct ft_sess *ft_sess_delete(struct ft_tport *tport, u32 port_id)
 249 {
 250         struct hlist_head *head;
 251         struct ft_sess *sess;
 252
 253         head = &tport->hash[ft_sess_hash(port_id)];
 254         hlist_for_each_entry_rcu(sess, head, hash) {
 255                 if (sess->port_id == port_id) {
 256                         ft_sess_unhash(sess);
 257                         return sess;
 258                 }
 259         }
 260         return NULL;
 261 }
 262
 263 /*
 264  * Delete all sessions from tport.
 265  * Caller holds ft_lport_lock.
 266  */
 267 static void ft_sess_delete_all(struct ft_tport *tport)
 268 {
 269         struct hlist_head *head;
 270         struct ft_sess *sess;
 271
 272         for (head = tport->hash;
 273              head < &tport->hash[FT_SESS_HASH_SIZE]; head++) {
 274                 hlist_for_each_entry_rcu(sess, head, hash) {
 275                         ft_sess_unhash(sess);
 276                         transport_deregister_session_configfs(sess->se_sess);
 277                         ft_sess_put(sess);      /* release from table */
 278                 }
 279         }
 280 }
 281
 282 /*
 283  * TCM ops for sessions.
 284  */
 285
 286 /*
 287  * Determine whether session is allowed to be shutdown in the current context.
 288  * Returns non-zero if the session should be shutdown.
 289  */
 290 int ft_sess_shutdown(struct se_session *se_sess)
 291 {
 292         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 293
 294         pr_debug("port_id %x\n", sess->port_id);
 295         return 1;
 296 }
 297
 298 /*
 299  * Remove session and send PRLO.
 300  * This is called when the ACL is being deleted or queue depth is changing.
 301  */
 302 void ft_sess_close(struct se_session *se_sess)
 303 {
 304         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 305         u32 port_id;
 306
 307         mutex_lock(&ft_lport_lock);
 308         port_id = sess->port_id;
 309         if (port_id == -1) {
 310                 mutex_unlock(&ft_lport_lock);
 311                 return;
 312         }
 313         pr_debug("port_id %x\n", port_id);
 314         ft_sess_unhash(sess);
 315         mutex_unlock(&ft_lport_lock);
 316         transport_deregister_session_configfs(se_sess);
 317         ft_sess_put(sess);
 318         /* XXX Send LOGO or PRLO */
 319         synchronize_rcu();              /* let transport deregister happen */
 320 }
 321
 322 u32 ft_sess_get_index(struct se_session *se_sess)
 323 {
 324         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 325
 326         return sess->port_id;   /* XXX TBD probably not what is needed */
 327 }
 328
 329 u32 ft_sess_get_port_name(struct se_session *se_sess,
 330                           unsigned char *buf, u32 len)
 331 {
 332         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 333
 334         return ft_format_wwn(buf, len, sess->port_name);
 335 }
 336
 337 /*
 338  * libfc ops involving sessions.
 339  */
 340
 341 static int ft_prli_locked(struct fc_rport_priv *rdata, u32 spp_len,
 342                           const struct fc_els_spp *rspp, struct fc_els_spp *spp)
 343 {
 344         struct ft_tport *tport;
 345         struct ft_sess *sess;
 346         struct ft_node_acl *acl;
 347         u32 fcp_parm;
 348
 349         tport = ft_tport_get(rdata->local_port);
 350         if (!tport)
 351                 goto not_target;        /* not a target for this local port */
 352
 353         acl = ft_acl_get(tport->tpg, rdata);
 354         if (!acl)
 355                 goto not_target;        /* no target for this remote */
 356
 357         if (!rspp)
 358                 goto fill;
 359
 360         if (rspp->spp_flags & (FC_SPP_OPA_VAL | FC_SPP_RPA_VAL))
 361                 return FC_SPP_RESP_NO_PA;
 362
 363         /*
 364          * If both target and initiator bits are off, the SPP is invalid.
 365          */
 366         fcp_parm = ntohl(rspp->spp_params);
 367         if (!(fcp_parm & (FCP_SPPF_INIT_FCN | FCP_SPPF_TARG_FCN)))
 368                 return FC_SPP_RESP_INVL;
 369
 370         /*
 371          * Create session (image pair) only if requested by
 372          * EST_IMG_PAIR flag and if the requestor is an initiator.
 373          */
 374         if (rspp->spp_flags & FC_SPP_EST_IMG_PAIR) {
 375                 spp->spp_flags |= FC_SPP_EST_IMG_PAIR;
 376                 if (!(fcp_parm & FCP_SPPF_INIT_FCN))
 377                         return FC_SPP_RESP_CONF;
 378                 sess = ft_sess_create(tport, rdata->ids.port_id, acl);
 379                 if (!sess)
 380                         return FC_SPP_RESP_RES;
 381                 if (!sess->params)
 382                         rdata->prli_count++;
 383                 sess->params = fcp_parm;
 384                 sess->port_name = rdata->ids.port_name;
 385                 sess->max_frame = rdata->maxframe_size;
 386
 387                 /* XXX TBD - clearing actions.  unit attn, see 4.10 */
 388         }
 389
 390         /*
 391          * OR in our service parameters with other provider (initiator), if any.
 392          */
 393 fill:
 394         fcp_parm = ntohl(spp->spp_params);
 395         fcp_parm &= ~FCP_SPPF_RETRY;
 396         spp->spp_params = htonl(fcp_parm | FCP_SPPF_TARG_FCN);
 397         return FC_SPP_RESP_ACK;
 398
 399 not_target:
 400         fcp_parm = ntohl(spp->spp_params);
 401         fcp_parm &= ~FCP_SPPF_TARG_FCN;
 402         spp->spp_params = htonl(fcp_parm);
 403         return 0;
 404 }
 405
 406 /**
 407  * tcm_fcp_prli() - Handle incoming or outgoing PRLI for the FCP target
 408  * @rdata: remote port private
 409  * @spp_len: service parameter page length
 410  * @rspp: received service parameter page (NULL for outgoing PRLI)
 411  * @spp: response service parameter page
 412  *
 413  * Returns spp response code.
 414  */
 415 static int ft_prli(struct fc_rport_priv *rdata, u32 spp_len,
 416                    const struct fc_els_spp *rspp, struct fc_els_spp *spp)
 417 {
 418         int ret;
 419
 420         mutex_lock(&ft_lport_lock);
 421         ret = ft_prli_locked(rdata, spp_len, rspp, spp);
 422         mutex_unlock(&ft_lport_lock);
 423         pr_debug("port_id %x flags %x ret %x\n",
 424                rdata->ids.port_id, rspp ? rspp->spp_flags : 0, ret);
 425         return ret;
 426 }
 427
 428 static void ft_sess_free(struct kref *kref)
 429 {
 430         struct ft_sess *sess = container_of(kref, struct ft_sess, kref);
 431
 432         transport_deregister_session(sess->se_sess);
 433         kfree_rcu(sess, rcu);
 434 }
 435
 436 void ft_sess_put(struct ft_sess *sess)
 437 {
 438         int sess_held = atomic_read(&sess->kref.refcount);
 439
 440         BUG_ON(!sess_held);
 441         kref_put(&sess->kref, ft_sess_free);
 442 }
 443
 444 static void ft_prlo(struct fc_rport_priv *rdata)
 445 {
 446         struct ft_sess *sess;
 447         struct ft_tport *tport;
 448
 449         mutex_lock(&ft_lport_lock);
 450         tport = rcu_dereference_protected(rdata->local_port->prov[FC_TYPE_FCP],
 451                                           lockdep_is_held(&ft_lport_lock));
 452
 453         if (!tport) {
 454                 mutex_unlock(&ft_lport_lock);
 455                 return;
 456         }
 457         sess = ft_sess_delete(tport, rdata->ids.port_id);
 458         if (!sess) {
 459                 mutex_unlock(&ft_lport_lock);
 460                 return;
 461         }
 462         mutex_unlock(&ft_lport_lock);
 463         transport_deregister_session_configfs(sess->se_sess);
 464         ft_sess_put(sess);              /* release from table */
 465         rdata->prli_count--;
 466         /* XXX TBD - clearing actions.  unit attn, see 4.10 */
 467 }
 468
 469 /*
 470  * Handle incoming FCP request.
 471  * Caller has verified that the frame is type FCP.
 472  */
 473 static void ft_recv(struct fc_lport *lport, struct fc_frame *fp)
 474 {
 475         struct ft_sess *sess;
 476         u32 sid = fc_frame_sid(fp);
 477
 478         pr_debug("sid %x\n", sid);
 479
 480         sess = ft_sess_get(lport, sid);
 481         if (!sess) {
 482                 pr_debug("sid %x sess lookup failed\n", sid);
 483                 /* TBD XXX - if FCP_CMND, send PRLO */
 484                 fc_frame_free(fp);
 485                 return;
 486         }
 487         ft_recv_req(sess, fp);  /* must do ft_sess_put() */
 488 }
 489
 490 /*
 491  * Provider ops for libfc.
 492  */
 493 struct fc4_prov ft_prov = {
 494         .prli = ft_prli,
 495         .prlo = ft_prlo,
 496         .recv = ft_recv,
 497         .module = THIS_MODULE,
 498 };