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_protected(lport->prov[FC_TYPE_FCP],
  62                                           lockdep_is_held(&ft_lport_lock));
  63         if (tport && tport->tpg)
  64                 return tport;
  65
  66         tpg = ft_lport_find_tpg(lport);
  67         if (!tpg)
  68                 return NULL;
  69
  70         if (tport) {
  71                 tport->tpg = tpg;
  72                 return tport;
  73         }
  74
  75         tport = kzalloc(sizeof(*tport), GFP_KERNEL);
  76         if (!tport)
  77                 return NULL;
  78
  79         tport->lport = lport;
  80         tport->tpg = tpg;
  81         tpg->tport = tport;
  82         for (i = 0; i < FT_SESS_HASH_SIZE; i++)
  83                 INIT_HLIST_HEAD(&tport->hash[i]);
  84
  85         rcu_assign_pointer(lport->prov[FC_TYPE_FCP], tport);
  86         return tport;
  87 }
  88
  89 /*
  90  * Delete a target local port.
  91  * Caller holds ft_lport_lock.
  92  */
  93 static void ft_tport_delete(struct ft_tport *tport)
  94 {
  95         struct fc_lport *lport;
  96         struct ft_tpg *tpg;
  97
  98         ft_sess_delete_all(tport);
  99         lport = tport->lport;
 100         BUG_ON(tport != lport->prov[FC_TYPE_FCP]);
 101         rcu_assign_pointer(lport->prov[FC_TYPE_FCP], NULL);
 102
 103         tpg = tport->tpg;
 104         if (tpg) {
 105                 tpg->tport = NULL;
 106                 tport->tpg = NULL;
 107         }
 108         kfree_rcu(tport, rcu);
 109 }
 110
 111 /*
 112  * Add local port.
 113  * Called thru fc_lport_iterate().
 114  */
 115 void ft_lport_add(struct fc_lport *lport, void *arg)
 116 {
 117         mutex_lock(&ft_lport_lock);
 118         ft_tport_create(lport);
 119         mutex_unlock(&ft_lport_lock);
 120 }
 121
 122 /*
 123  * Delete local port.
 124  * Called thru fc_lport_iterate().
 125  */
 126 void ft_lport_del(struct fc_lport *lport, void *arg)
 127 {
 128         struct ft_tport *tport;
 129
 130         mutex_lock(&ft_lport_lock);
 131         tport = lport->prov[FC_TYPE_FCP];
 132         if (tport)
 133                 ft_tport_delete(tport);
 134         mutex_unlock(&ft_lport_lock);
 135 }
 136
 137 /*
 138  * Notification of local port change from libfc.
 139  * Create or delete local port and associated tport.
 140  */
 141 int ft_lport_notify(struct notifier_block *nb, unsigned long event, void *arg)
 142 {
 143         struct fc_lport *lport = arg;
 144
 145         switch (event) {
 146         case FC_LPORT_EV_ADD:
 147                 ft_lport_add(lport, NULL);
 148                 break;
 149         case FC_LPORT_EV_DEL:
 150                 ft_lport_del(lport, NULL);
 151                 break;
 152         }
 153         return NOTIFY_DONE;
 154 }
 155
 156 /*
 157  * Hash function for FC_IDs.
 158  */
 159 static u32 ft_sess_hash(u32 port_id)
 160 {
 161         return hash_32(port_id, FT_SESS_HASH_BITS);
 162 }
 163
 164 /*
 165  * Find session in local port.
 166  * Sessions and hash lists are RCU-protected.
 167  * A reference is taken which must be eventually freed.
 168  */
 169 static struct ft_sess *ft_sess_get(struct fc_lport *lport, u32 port_id)
 170 {
 171         struct ft_tport *tport;
 172         struct hlist_head *head;
 173         struct hlist_node *pos;
 174         struct ft_sess *sess;
 175
 176         rcu_read_lock();
 177         tport = rcu_dereference(lport->prov[FC_TYPE_FCP]);
 178         if (!tport)
 179                 goto out;
 180
 181         head = &tport->hash[ft_sess_hash(port_id)];
 182         hlist_for_each_entry_rcu(sess, pos, head, hash) {
 183                 if (sess->port_id == port_id) {
 184                         kref_get(&sess->kref);
 185                         rcu_read_unlock();
 186                         pr_debug("port_id %x found %p\n", port_id, sess);
 187                         return sess;
 188                 }
 189         }
 190 out:
 191         rcu_read_unlock();
 192         pr_debug("port_id %x not found\n", port_id);
 193         return NULL;
 194 }
 195
 196 /*
 197  * Allocate session and enter it in the hash for the local port.
 198  * Caller holds ft_lport_lock.
 199  */
 200 static struct ft_sess *ft_sess_create(struct ft_tport *tport, u32 port_id,
 201                                       struct ft_node_acl *acl)
 202 {
 203         struct ft_sess *sess;
 204         struct hlist_head *head;
 205         struct hlist_node *pos;
 206
 207         head = &tport->hash[ft_sess_hash(port_id)];
 208         hlist_for_each_entry_rcu(sess, pos, head, hash)
 209                 if (sess->port_id == port_id)
 210                         return sess;
 211
 212         sess = kzalloc(sizeof(*sess), GFP_KERNEL);
 213         if (!sess)
 214                 return NULL;
 215
 216         sess->se_sess = transport_init_session();
 217         if (IS_ERR(sess->se_sess)) {
 218                 kfree(sess);
 219                 return NULL;
 220         }
 221         sess->se_sess->se_node_acl = &acl->se_node_acl;
 222         sess->tport = tport;
 223         sess->port_id = port_id;
 224         kref_init(&sess->kref); /* ref for table entry */
 225         hlist_add_head_rcu(&sess->hash, head);
 226         tport->sess_count++;
 227
 228         pr_debug("port_id %x sess %p\n", port_id, sess);
 229
 230         transport_register_session(&tport->tpg->se_tpg, &acl->se_node_acl,
 231                                    sess->se_sess, sess);
 232         return sess;
 233 }
 234
 235 /*
 236  * Unhash the session.
 237  * Caller holds ft_lport_lock.
 238  */
 239 static void ft_sess_unhash(struct ft_sess *sess)
 240 {
 241         struct ft_tport *tport = sess->tport;
 242
 243         hlist_del_rcu(&sess->hash);
 244         BUG_ON(!tport->sess_count);
 245         tport->sess_count--;
 246         sess->port_id = -1;
 247         sess->params = 0;
 248 }
 249
 250 /*
 251  * Delete session from hash.
 252  * Caller holds ft_lport_lock.
 253  */
 254 static struct ft_sess *ft_sess_delete(struct ft_tport *tport, u32 port_id)
 255 {
 256         struct hlist_head *head;
 257         struct hlist_node *pos;
 258         struct ft_sess *sess;
 259
 260         head = &tport->hash[ft_sess_hash(port_id)];
 261         hlist_for_each_entry_rcu(sess, pos, head, hash) {
 262                 if (sess->port_id == port_id) {
 263                         ft_sess_unhash(sess);
 264                         return sess;
 265                 }
 266         }
 267         return NULL;
 268 }
 269
 270 /*
 271  * Delete all sessions from tport.
 272  * Caller holds ft_lport_lock.
 273  */
 274 static void ft_sess_delete_all(struct ft_tport *tport)
 275 {
 276         struct hlist_head *head;
 277         struct hlist_node *pos;
 278         struct ft_sess *sess;
 279
 280         for (head = tport->hash;
 281              head < &tport->hash[FT_SESS_HASH_SIZE]; head++) {
 282                 hlist_for_each_entry_rcu(sess, pos, head, hash) {
 283                         ft_sess_unhash(sess);
 284                         transport_deregister_session_configfs(sess->se_sess);
 285                         ft_sess_put(sess);      /* release from table */
 286                 }
 287         }
 288 }
 289
 290 /*
 291  * TCM ops for sessions.
 292  */
 293
 294 /*
 295  * Determine whether session is allowed to be shutdown in the current context.
 296  * Returns non-zero if the session should be shutdown.
 297  */
 298 int ft_sess_shutdown(struct se_session *se_sess)
 299 {
 300         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 301
 302         pr_debug("port_id %x\n", sess->port_id);
 303         return 1;
 304 }
 305
 306 /*
 307  * Remove session and send PRLO.
 308  * This is called when the ACL is being deleted or queue depth is changing.
 309  */
 310 void ft_sess_close(struct se_session *se_sess)
 311 {
 312         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 313         u32 port_id;
 314
 315         mutex_lock(&ft_lport_lock);
 316         port_id = sess->port_id;
 317         if (port_id == -1) {
 318                 mutex_unlock(&ft_lport_lock);
 319                 return;
 320         }
 321         pr_debug("port_id %x\n", port_id);
 322         ft_sess_unhash(sess);
 323         mutex_unlock(&ft_lport_lock);
 324         transport_deregister_session_configfs(se_sess);
 325         ft_sess_put(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         struct ft_node_acl *acl;
 355         u32 fcp_parm;
 356
 357         tport = ft_tport_create(rdata->local_port);
 358         if (!tport)
 359                 return 0;       /* not a target for this local port */
 360
 361         acl = ft_acl_get(tport->tpg, rdata);
 362         if (!acl)
 363                 return 0;
 364
 365         if (!rspp)
 366                 goto fill;
 367
 368         if (rspp->spp_flags & (FC_SPP_OPA_VAL | FC_SPP_RPA_VAL))
 369                 return FC_SPP_RESP_NO_PA;
 370
 371         /*
 372          * If both target and initiator bits are off, the SPP is invalid.
 373          */
 374         fcp_parm = ntohl(rspp->spp_params);
 375         if (!(fcp_parm & (FCP_SPPF_INIT_FCN | FCP_SPPF_TARG_FCN)))
 376                 return FC_SPP_RESP_INVL;
 377
 378         /*
 379          * Create session (image pair) only if requested by
 380          * EST_IMG_PAIR flag and if the requestor is an initiator.
 381          */
 382         if (rspp->spp_flags & FC_SPP_EST_IMG_PAIR) {
 383                 spp->spp_flags |= FC_SPP_EST_IMG_PAIR;
 384                 if (!(fcp_parm & FCP_SPPF_INIT_FCN))
 385                         return FC_SPP_RESP_CONF;
 386                 sess = ft_sess_create(tport, rdata->ids.port_id, acl);
 387                 if (!sess)
 388                         return FC_SPP_RESP_RES;
 389                 if (!sess->params)
 390                         rdata->prli_count++;
 391                 sess->params = fcp_parm;
 392                 sess->port_name = rdata->ids.port_name;
 393                 sess->max_frame = rdata->maxframe_size;
 394
 395                 /* XXX TBD - clearing actions.  unit attn, see 4.10 */
 396         }
 397
 398         /*
 399          * OR in our service parameters with other provider (initiator), if any.
 400          * TBD XXX - indicate RETRY capability?
 401          */
 402 fill:
 403         fcp_parm = ntohl(spp->spp_params);
 404         spp->spp_params = htonl(fcp_parm | FCP_SPPF_TARG_FCN);
 405         return FC_SPP_RESP_ACK;
 406 }
 407
 408 /**
 409  * tcm_fcp_prli() - Handle incoming or outgoing PRLI for the FCP target
 410  * @rdata: remote port private
 411  * @spp_len: service parameter page length
 412  * @rspp: received service parameter page (NULL for outgoing PRLI)
 413  * @spp: response service parameter page
 414  *
 415  * Returns spp response code.
 416  */
 417 static int ft_prli(struct fc_rport_priv *rdata, u32 spp_len,
 418                    const struct fc_els_spp *rspp, struct fc_els_spp *spp)
 419 {
 420         int ret;
 421
 422         mutex_lock(&ft_lport_lock);
 423         ret = ft_prli_locked(rdata, spp_len, rspp, spp);
 424         mutex_unlock(&ft_lport_lock);
 425         pr_debug("port_id %x flags %x ret %x\n",
 426                rdata->ids.port_id, rspp ? rspp->spp_flags : 0, ret);
 427         return ret;
 428 }
 429
 430 static void ft_sess_rcu_free(struct rcu_head *rcu)
 431 {
 432         struct ft_sess *sess = container_of(rcu, struct ft_sess, rcu);
 433
 434         transport_deregister_session(sess->se_sess);
 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         call_rcu(&sess->rcu, ft_sess_rcu_free);
 443 }
 444
 445 void ft_sess_put(struct ft_sess *sess)
 446 {
 447         int sess_held = atomic_read(&sess->kref.refcount);
 448
 449         BUG_ON(!sess_held);
 450         kref_put(&sess->kref, ft_sess_free);
 451 }
 452
 453 static void ft_prlo(struct fc_rport_priv *rdata)
 454 {
 455         struct ft_sess *sess;
 456         struct ft_tport *tport;
 457
 458         mutex_lock(&ft_lport_lock);
 459         tport = rcu_dereference(rdata->local_port->prov[FC_TYPE_FCP]);
 460         if (!tport) {
 461                 mutex_unlock(&ft_lport_lock);
 462                 return;
 463         }
 464         sess = ft_sess_delete(tport, rdata->ids.port_id);
 465         if (!sess) {
 466                 mutex_unlock(&ft_lport_lock);
 467                 return;
 468         }
 469         mutex_unlock(&ft_lport_lock);
 470         transport_deregister_session_configfs(sess->se_sess);
 471         ft_sess_put(sess);              /* release from table */
 472         rdata->prli_count--;
 473         /* XXX TBD - clearing actions.  unit attn, see 4.10 */
 474 }
 475
 476 /*
 477  * Handle incoming FCP request.
 478  * Caller has verified that the frame is type FCP.
 479  */
 480 static void ft_recv(struct fc_lport *lport, struct fc_frame *fp)
 481 {
 482         struct ft_sess *sess;
 483         u32 sid = fc_frame_sid(fp);
 484
 485         pr_debug("sid %x\n", sid);
 486
 487         sess = ft_sess_get(lport, sid);
 488         if (!sess) {
 489                 pr_debug("sid %x sess lookup failed\n", sid);
 490                 /* TBD XXX - if FCP_CMND, send PRLO */
 491                 fc_frame_free(fp);
 492                 return;
 493         }
 494         ft_recv_req(sess, fp);  /* must do ft_sess_put() */
 495 }
 496
 497 /*
 498  * Provider ops for libfc.
 499  */
 500 struct fc4_prov ft_prov = {
 501         .prli = ft_prli,
 502         .prlo = ft_prlo,
 503         .recv = ft_recv,
 504         .module = THIS_MODULE,
 505 };