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                 tpg->tport = tport;
  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 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, 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
 205         head = &tport->hash[ft_sess_hash(port_id)];
 206         hlist_for_each_entry_rcu(sess, head, hash)
 207                 if (sess->port_id == port_id)
 208                         return sess;
 209
 210         sess = kzalloc(sizeof(*sess), GFP_KERNEL);
 211         if (!sess)
 212                 return NULL;
 213
 214         sess->se_sess = transport_init_session();
 215         if (IS_ERR(sess->se_sess)) {
 216                 kfree(sess);
 217                 return NULL;
 218         }
 219         sess->se_sess->se_node_acl = &acl->se_node_acl;
 220         sess->tport = tport;
 221         sess->port_id = port_id;
 222         kref_init(&sess->kref); /* ref for table entry */
 223         hlist_add_head_rcu(&sess->hash, head);
 224         tport->sess_count++;
 225
 226         pr_debug("port_id %x sess %p\n", port_id, sess);
 227
 228         transport_register_session(&tport->tpg->se_tpg, &acl->se_node_acl,
 229                                    sess->se_sess, sess);
 230         return sess;
 231 }
 232
 233 /*
 234  * Unhash the session.
 235  * Caller holds ft_lport_lock.
 236  */
 237 static void ft_sess_unhash(struct ft_sess *sess)
 238 {
 239         struct ft_tport *tport = sess->tport;
 240
 241         hlist_del_rcu(&sess->hash);
 242         BUG_ON(!tport->sess_count);
 243         tport->sess_count--;
 244         sess->port_id = -1;
 245         sess->params = 0;
 246 }
 247
 248 /*
 249  * Delete session from hash.
 250  * Caller holds ft_lport_lock.
 251  */
 252 static struct ft_sess *ft_sess_delete(struct ft_tport *tport, u32 port_id)
 253 {
 254         struct hlist_head *head;
 255         struct ft_sess *sess;
 256
 257         head = &tport->hash[ft_sess_hash(port_id)];
 258         hlist_for_each_entry_rcu(sess, head, hash) {
 259                 if (sess->port_id == port_id) {
 260                         ft_sess_unhash(sess);
 261                         return sess;
 262                 }
 263         }
 264         return NULL;
 265 }
 266
 267 /*
 268  * Delete all sessions from tport.
 269  * Caller holds ft_lport_lock.
 270  */
 271 static void ft_sess_delete_all(struct ft_tport *tport)
 272 {
 273         struct hlist_head *head;
 274         struct ft_sess *sess;
 275
 276         for (head = tport->hash;
 277              head < &tport->hash[FT_SESS_HASH_SIZE]; head++) {
 278                 hlist_for_each_entry_rcu(sess, head, hash) {
 279                         ft_sess_unhash(sess);
 280                         transport_deregister_session_configfs(sess->se_sess);
 281                         ft_sess_put(sess);      /* release from table */
 282                 }
 283         }
 284 }
 285
 286 /*
 287  * TCM ops for sessions.
 288  */
 289
 290 /*
 291  * Determine whether session is allowed to be shutdown in the current context.
 292  * Returns non-zero if the session should be shutdown.
 293  */
 294 int ft_sess_shutdown(struct se_session *se_sess)
 295 {
 296         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 297
 298         pr_debug("port_id %x\n", sess->port_id);
 299         return 1;
 300 }
 301
 302 /*
 303  * Remove session and send PRLO.
 304  * This is called when the ACL is being deleted or queue depth is changing.
 305  */
 306 void ft_sess_close(struct se_session *se_sess)
 307 {
 308         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 309         u32 port_id;
 310
 311         mutex_lock(&ft_lport_lock);
 312         port_id = sess->port_id;
 313         if (port_id == -1) {
 314                 mutex_unlock(&ft_lport_lock);
 315                 return;
 316         }
 317         pr_debug("port_id %x\n", port_id);
 318         ft_sess_unhash(sess);
 319         mutex_unlock(&ft_lport_lock);
 320         transport_deregister_session_configfs(se_sess);
 321         ft_sess_put(sess);
 322         /* XXX Send LOGO or PRLO */
 323         synchronize_rcu();              /* let transport deregister happen */
 324 }
 325
 326 u32 ft_sess_get_index(struct se_session *se_sess)
 327 {
 328         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 329
 330         return sess->port_id;   /* XXX TBD probably not what is needed */
 331 }
 332
 333 u32 ft_sess_get_port_name(struct se_session *se_sess,
 334                           unsigned char *buf, u32 len)
 335 {
 336         struct ft_sess *sess = se_sess->fabric_sess_ptr;
 337
 338         return ft_format_wwn(buf, len, sess->port_name);
 339 }
 340
 341 /*
 342  * libfc ops involving sessions.
 343  */
 344
 345 static int ft_prli_locked(struct fc_rport_priv *rdata, u32 spp_len,
 346                           const struct fc_els_spp *rspp, struct fc_els_spp *spp)
 347 {
 348         struct ft_tport *tport;
 349         struct ft_sess *sess;
 350         struct ft_node_acl *acl;
 351         u32 fcp_parm;
 352
 353         tport = ft_tport_create(rdata->local_port);
 354         if (!tport)
 355                 goto not_target;        /* not a target for this local port */
 356
 357         acl = ft_acl_get(tport->tpg, rdata);
 358         if (!acl)
 359                 goto not_target;        /* no target for this remote */
 360
 361         if (!rspp)
 362                 goto fill;
 363
 364         if (rspp->spp_flags & (FC_SPP_OPA_VAL | FC_SPP_RPA_VAL))
 365                 return FC_SPP_RESP_NO_PA;
 366
 367         /*
 368          * If both target and initiator bits are off, the SPP is invalid.
 369          */
 370         fcp_parm = ntohl(rspp->spp_params);
 371         if (!(fcp_parm & (FCP_SPPF_INIT_FCN | FCP_SPPF_TARG_FCN)))
 372                 return FC_SPP_RESP_INVL;
 373
 374         /*
 375          * Create session (image pair) only if requested by
 376          * EST_IMG_PAIR flag and if the requestor is an initiator.
 377          */
 378         if (rspp->spp_flags & FC_SPP_EST_IMG_PAIR) {
 379                 spp->spp_flags |= FC_SPP_EST_IMG_PAIR;
 380                 if (!(fcp_parm & FCP_SPPF_INIT_FCN))
 381                         return FC_SPP_RESP_CONF;
 382                 sess = ft_sess_create(tport, rdata->ids.port_id, acl);
 383                 if (!sess)
 384                         return FC_SPP_RESP_RES;
 385                 if (!sess->params)
 386                         rdata->prli_count++;
 387                 sess->params = fcp_parm;
 388                 sess->port_name = rdata->ids.port_name;
 389                 sess->max_frame = rdata->maxframe_size;
 390
 391                 /* XXX TBD - clearing actions.  unit attn, see 4.10 */
 392         }
 393
 394         /*
 395          * OR in our service parameters with other provider (initiator), if any.
 396          */
 397 fill:
 398         fcp_parm = ntohl(spp->spp_params);
 399         fcp_parm &= ~FCP_SPPF_RETRY;
 400         spp->spp_params = htonl(fcp_parm | FCP_SPPF_TARG_FCN);
 401         return FC_SPP_RESP_ACK;
 402
 403 not_target:
 404         fcp_parm = ntohl(spp->spp_params);
 405         fcp_parm &= ~FCP_SPPF_TARG_FCN;
 406         spp->spp_params = htonl(fcp_parm);
 407         return 0;
 408 }
 409
 410 /**
 411  * tcm_fcp_prli() - Handle incoming or outgoing PRLI for the FCP target
 412  * @rdata: remote port private
 413  * @spp_len: service parameter page length
 414  * @rspp: received service parameter page (NULL for outgoing PRLI)
 415  * @spp: response service parameter page
 416  *
 417  * Returns spp response code.
 418  */
 419 static int ft_prli(struct fc_rport_priv *rdata, u32 spp_len,
 420                    const struct fc_els_spp *rspp, struct fc_els_spp *spp)
 421 {
 422         int ret;
 423
 424         mutex_lock(&ft_lport_lock);
 425         ret = ft_prli_locked(rdata, spp_len, rspp, spp);
 426         mutex_unlock(&ft_lport_lock);
 427         pr_debug("port_id %x flags %x ret %x\n",
 428                rdata->ids.port_id, rspp ? rspp->spp_flags : 0, ret);
 429         return ret;
 430 }
 431
 432 static void ft_sess_free(struct kref *kref)
 433 {
 434         struct ft_sess *sess = container_of(kref, struct ft_sess, kref);
 435
 436         transport_deregister_session(sess->se_sess);
 437         kfree_rcu(sess, rcu);
 438 }
 439
 440 void ft_sess_put(struct ft_sess *sess)
 441 {
 442         int sess_held = atomic_read(&sess->kref.refcount);
 443
 444         BUG_ON(!sess_held);
 445         kref_put(&sess->kref, ft_sess_free);
 446 }
 447
 448 static void ft_prlo(struct fc_rport_priv *rdata)
 449 {
 450         struct ft_sess *sess;
 451         struct ft_tport *tport;
 452
 453         mutex_lock(&ft_lport_lock);
 454         tport = rcu_dereference_protected(rdata->local_port->prov[FC_TYPE_FCP],
 455                                           lockdep_is_held(&ft_lport_lock));
 456
 457         if (!tport) {
 458                 mutex_unlock(&ft_lport_lock);
 459                 return;
 460         }
 461         sess = ft_sess_delete(tport, rdata->ids.port_id);
 462         if (!sess) {
 463                 mutex_unlock(&ft_lport_lock);
 464                 return;
 465         }
 466         mutex_unlock(&ft_lport_lock);
 467         transport_deregister_session_configfs(sess->se_sess);
 468         ft_sess_put(sess);              /* release from table */
 469         rdata->prli_count--;
 470         /* XXX TBD - clearing actions.  unit attn, see 4.10 */
 471 }
 472
 473 /*
 474  * Handle incoming FCP request.
 475  * Caller has verified that the frame is type FCP.
 476  */
 477 static void ft_recv(struct fc_lport *lport, struct fc_frame *fp)
 478 {
 479         struct ft_sess *sess;
 480         u32 sid = fc_frame_sid(fp);
 481
 482         pr_debug("sid %x\n", sid);
 483
 484         sess = ft_sess_get(lport, sid);
 485         if (!sess) {
 486                 pr_debug("sid %x sess lookup failed\n", sid);
 487                 /* TBD XXX - if FCP_CMND, send PRLO */
 488                 fc_frame_free(fp);
 489                 return;
 490         }
 491         ft_recv_req(sess, fp);  /* must do ft_sess_put() */
 492 }
 493
 494 /*
 495  * Provider ops for libfc.
 496  */
 497 struct fc4_prov ft_prov = {
 498         .prli = ft_prli,
 499         .prlo = ft_prlo,
 500         .recv = ft_recv,
 501         .module = THIS_MODULE,
 502 };