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/scsi.h>
  36 #include <scsi/scsi_host.h>
  37 #include <scsi/scsi_device.h>
  38 #include <scsi/scsi_cmnd.h>
  39 #include <scsi/libfc.h>
  40
  41 #include <target/target_core_base.h>
  42 #include <target/target_core_fabric.h>
  43 #include <target/target_core_configfs.h>
  44 #include <target/configfs_macros.h>
  45
  46 #include "tcm_fc.h"
  47
  48 static void ft_sess_delete_all(struct ft_tport *);
  49
  50 /*
  51  * Lookup or allocate target local port.
  52  * Caller holds ft_lport_lock.
  53  */
  54 static struct ft_tport *ft_tport_create(struct fc_lport *lport)
  55 {
  56         struct ft_tpg *tpg;
  57         struct ft_tport *tport;
  58         int i;
  59
  60         tport = rcu_dereference_protected(lport->prov[FC_TYPE_FCP],
  61                                           lockdep_is_held(&ft_lport_lock));
  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 ft_sess *sess;
 173
 174         rcu_read_lock();
 175         tport = rcu_dereference(lport->prov[FC_TYPE_FCP]);
 176         if (!tport)
 177                 goto out;
 178
 179         head = &tport->hash[ft_sess_hash(port_id)];
 180         hlist_for_each_entry_rcu(sess, head, hash) {
 181                 if (sess->port_id == port_id) {
 182                         kref_get(&sess->kref);
 183                         rcu_read_unlock();
 184                         pr_debug("port_id %x found %p\n", port_id, sess);
 185                         return sess;
 186                 }
 187         }
 188 out:
 189         rcu_read_unlock();
 190         pr_debug("port_id %x not found\n", port_id);
 191         return NULL;
 192 }
 193
 194 /*
 195  * Allocate session and enter it in the hash for the local port.
 196  * Caller holds ft_lport_lock.
 197  */
 198 static struct ft_sess *ft_sess_create(struct ft_tport *tport, u32 port_id,
 199                                       struct ft_node_acl *acl)
 200 {
 201         struct ft_sess *sess;
 202         struct hlist_head *head;
 203
 204         head = &tport->hash[ft_sess_hash(port_id)];
 205         hlist_for_each_entry_rcu(sess, head, hash)
 206                 if (sess->port_id == port_id)
 207                         return sess;
 208
 209         sess = kzalloc(sizeof(*sess), GFP_KERNEL);
 210         if (!sess)
 211                 return NULL;
 212
 213         sess->se_sess = transport_init_session();
 214         if (IS_ERR(sess->se_sess)) {
 215                 kfree(sess);
 216                 return NULL;
 217         }
 218         sess->se_sess->se_node_acl = &acl->se_node_acl;
 219         sess->tport = tport;
 220         sess->port_id = port_id;
 221         kref_init(&sess->kref); /* ref for table entry */
 222         hlist_add_head_rcu(&sess->hash, head);
 223         tport->sess_count++;
 224
 225         pr_debug("port_id %x sess %p\n", port_id, sess);
 226
 227         transport_register_session(&tport->tpg->se_tpg, &acl->se_node_acl,
 228                                    sess->se_sess, sess);
 229         return sess;
 230 }
 231
 232 /*
 233  * Unhash the session.
 234  * Caller holds ft_lport_lock.
 235  */
 236 static void ft_sess_unhash(struct ft_sess *sess)
 237 {
 238         struct ft_tport *tport = sess->tport;
 239
 240         hlist_del_rcu(&sess->hash);
 241         BUG_ON(!tport->sess_count);
 242         tport->sess_count--;
 243         sess->port_id = -1;
 244         sess->params = 0;
 245 }
 246
 247 /*
 248  * Delete session from hash.
 249  * Caller holds ft_lport_lock.
 250  */
 251 static struct ft_sess *ft_sess_delete(struct ft_tport *tport, u32 port_id)
 252 {
 253         struct hlist_head *head;
 254         struct ft_sess *sess;
 255
 256         head = &tport->hash[ft_sess_hash(port_id)];
 257         hlist_for_each_entry_rcu(sess, head, hash) {
 258                 if (sess->port_id == port_id) {
 259                         ft_sess_unhash(sess);
 260                         return sess;
 261                 }
 262         }
 263         return NULL;
 264 }
 265
 266 /*
 267  * Delete all sessions from tport.
 268  * Caller holds ft_lport_lock.
 269  */
 270 static void ft_sess_delete_all(struct ft_tport *tport)
 271 {
 272         struct hlist_head *head;
 273         struct ft_sess *sess;
 274
 275         for (head = tport->hash;
 276              head < &tport->hash[FT_SESS_HASH_SIZE]; head++) {
 277                 hlist_for_each_entry_rcu(sess, head, hash) {
 278                         ft_sess_unhash(sess);
 279                         transport_deregister_session_configfs(sess->se_sess);
 280                         ft_sess_put(sess);      /* release from table */
 281                 }
 282         }
 283 }
 284
 285 /*
 286  * TCM ops for sessions.
 287  */
 288
 289 /*
 290  * Determine whether session is allowed to be shutdown in the current context.
 291  * Returns non-zero if the session should be shutdown.
 292  */
 293 int ft_sess_shutdown(struct se_session *se_sess)
 294 {
 295         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 296
 297         pr_debug("port_id %x\n", sess->port_id);
 298         return 1;
 299 }
 300
 301 /*
 302  * Remove session and send PRLO.
 303  * This is called when the ACL is being deleted or queue depth is changing.
 304  */
 305 void ft_sess_close(struct se_session *se_sess)
 306 {
 307         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 308         u32 port_id;
 309
 310         mutex_lock(&ft_lport_lock);
 311         port_id = sess->port_id;
 312         if (port_id == -1) {
 313                 mutex_unlock(&ft_lport_lock);
 314                 return;
 315         }
 316         pr_debug("port_id %x\n", port_id);
 317         ft_sess_unhash(sess);
 318         mutex_unlock(&ft_lport_lock);
 319         transport_deregister_session_configfs(se_sess);
 320         ft_sess_put(sess);
 321         /* XXX Send LOGO or PRLO */
 322         synchronize_rcu();              /* let transport deregister happen */
 323 }
 324
 325 u32 ft_sess_get_index(struct se_session *se_sess)
 326 {
 327         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 328
 329         return sess->port_id;   /* XXX TBD probably not what is needed */
 330 }
 331
 332 u32 ft_sess_get_port_name(struct se_session *se_sess,
 333                           unsigned char *buf, u32 len)
 334 {
 335         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 336
 337         return ft_format_wwn(buf, len, sess->port_name);
 338 }
 339
 340 /*
 341  * libfc ops involving sessions.
 342  */
 343
 344 static int ft_prli_locked(struct fc_rport_priv *rdata, u32 spp_len,
 345                           const struct fc_els_spp *rspp, struct fc_els_spp *spp)
 346 {
 347         struct ft_tport *tport;
 348         struct ft_sess *sess;
 349         struct ft_node_acl *acl;
 350         u32 fcp_parm;
 351
 352         tport = ft_tport_create(rdata->local_port);
 353         if (!tport)
 354                 goto not_target;        /* not a target for this local port */
 355
 356         acl = ft_acl_get(tport->tpg, rdata);
 357         if (!acl)
 358                 goto not_target;        /* no target for this remote */
 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, acl);
 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_rcu_free(struct rcu_head *rcu)
 432 {
 433         struct ft_sess *sess = container_of(rcu, struct ft_sess, rcu);
 434
 435         kfree(sess);
 436 }
 437
 438 static void ft_sess_free(struct kref *kref)
 439 {
 440         struct ft_sess *sess = container_of(kref, struct ft_sess, kref);
 441
 442         transport_deregister_session(sess->se_sess);
 443         call_rcu(&sess->rcu, ft_sess_rcu_free);
 444 }
 445
 446 void ft_sess_put(struct ft_sess *sess)
 447 {
 448         int sess_held = atomic_read(&sess->kref.refcount);
 449
 450         BUG_ON(!sess_held);
 451         kref_put(&sess->kref, ft_sess_free);
 452 }
 453
 454 static void ft_prlo(struct fc_rport_priv *rdata)
 455 {
 456         struct ft_sess *sess;
 457         struct ft_tport *tport;
 458
 459         mutex_lock(&ft_lport_lock);
 460         tport = rcu_dereference_protected(rdata->local_port->prov[FC_TYPE_FCP],
 461                                           lockdep_is_held(&ft_lport_lock));
 462
 463         if (!tport) {
 464                 mutex_unlock(&ft_lport_lock);
 465                 return;
 466         }
 467         sess = ft_sess_delete(tport, rdata->ids.port_id);
 468         if (!sess) {
 469                 mutex_unlock(&ft_lport_lock);
 470                 return;
 471         }
 472         mutex_unlock(&ft_lport_lock);
 473         transport_deregister_session_configfs(sess->se_sess);
 474         ft_sess_put(sess);              /* release from table */
 475         rdata->prli_count--;
 476         /* XXX TBD - clearing actions.  unit attn, see 4.10 */
 477 }
 478
 479 /*
 480  * Handle incoming FCP request.
 481  * Caller has verified that the frame is type FCP.
 482  */
 483 static void ft_recv(struct fc_lport *lport, struct fc_frame *fp)
 484 {
 485         struct ft_sess *sess;
 486         u32 sid = fc_frame_sid(fp);
 487
 488         pr_debug("sid %x\n", sid);
 489
 490         sess = ft_sess_get(lport, sid);
 491         if (!sess) {
 492                 pr_debug("sid %x sess lookup failed\n", sid);
 493                 /* TBD XXX - if FCP_CMND, send PRLO */
 494                 fc_frame_free(fp);
 495                 return;
 496         }
 497         ft_recv_req(sess, fp);  /* must do ft_sess_put() */
 498 }
 499
 500 /*
 501  * Provider ops for libfc.
 502  */
 503 struct fc4_prov ft_prov = {
 504         .prli = ft_prli,
 505         .prlo = ft_prlo,
 506         .recv = ft_recv,
 507         .module = THIS_MODULE,
 508 };