drivers/scsi/libfc/fc_disc.c

   1 /*
   2  * Copyright(c) 2007 - 2008 Intel Corporation. All rights reserved.
   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  * Maintained at www.Open-FCoE.org
  18  */
  19
  20 /*
  21  * Target Discovery
  22  *
  23  * This block discovers all FC-4 remote ports, including FCP initiators. It
  24  * also handles RSCN events and re-discovery if necessary.
  25  */
  26
  27 /*
  28  * DISC LOCKING
  29  *
  30  * The disc mutex is can be locked when acquiring rport locks, but may not
  31  * be held when acquiring the lport lock. Refer to fc_lport.c for more
  32  * details.
  33  */
  34
  35 #include <linux/timer.h>
  36 #include <linux/err.h>
  37 #include <asm/unaligned.h>
  38
  39 #include <scsi/fc/fc_gs.h>
  40
  41 #include <scsi/libfc.h>
  42
  43 #define FC_DISC_RETRY_LIMIT     3       /* max retries */
  44 #define FC_DISC_RETRY_DELAY     500UL   /* (msecs) delay */
  45
  46 #define FC_DISC_DELAY           3
  47
  48 static void fc_disc_gpn_ft_req(struct fc_disc *);
  49 static void fc_disc_gpn_ft_resp(struct fc_seq *, struct fc_frame *, void *);
  50 static int fc_disc_new_target(struct fc_disc *, struct fc_rport *,
  51                               struct fc_rport_identifiers *);
  52 static void fc_disc_del_target(struct fc_disc *, struct fc_rport *);
  53 static void fc_disc_done(struct fc_disc *);
  54 static void fc_disc_timeout(struct work_struct *);
  55 static void fc_disc_single(struct fc_disc *, struct fc_disc_port *);
  56 static void fc_disc_restart(struct fc_disc *);
  57
  58 /**
  59  * fc_disc_lookup_rport() - lookup a remote port by port_id
  60  * @lport: Fibre Channel host port instance
  61  * @port_id: remote port port_id to match
  62  */
  63 struct fc_rport *fc_disc_lookup_rport(const struct fc_lport *lport,
  64                                       u32 port_id)
  65 {
  66         const struct fc_disc *disc = &lport->disc;
  67         struct fc_rport *rport, *found = NULL;
  68         struct fc_rport_priv *rdata;
  69         int disc_found = 0;
  70
  71         list_for_each_entry(rdata, &disc->rports, peers) {
  72                 rport = PRIV_TO_RPORT(rdata);
  73                 if (rport->port_id == port_id) {
  74                         disc_found = 1;
  75                         found = rport;
  76                         break;
  77                 }
  78         }
  79
  80         if (!disc_found)
  81                 found = NULL;
  82
  83         return found;
  84 }
  85
  86 /**
  87  * fc_disc_stop_rports() - delete all the remote ports associated with the lport
  88  * @disc: The discovery job to stop rports on
  89  *
  90  * Locking Note: This function expects that the lport mutex is locked before
  91  * calling it.
  92  */
  93 void fc_disc_stop_rports(struct fc_disc *disc)
  94 {
  95         struct fc_lport *lport;
  96         struct fc_rport *rport;
  97         struct fc_rport_priv *rdata, *next;
  98
  99         lport = disc->lport;
 100
 101         mutex_lock(&disc->disc_mutex);
 102         list_for_each_entry_safe(rdata, next, &disc->rports, peers) {
 103                 rport = PRIV_TO_RPORT(rdata);
 104                 list_del(&rdata->peers);
 105                 lport->tt.rport_logoff(rport);
 106         }
 107
 108         list_for_each_entry_safe(rdata, next, &disc->rogue_rports, peers) {
 109                 rport = PRIV_TO_RPORT(rdata);
 110                 lport->tt.rport_logoff(rport);
 111         }
 112
 113         mutex_unlock(&disc->disc_mutex);
 114 }
 115
 116 /**
 117  * fc_disc_rport_callback() - Event handler for rport events
 118  * @lport: The lport which is receiving the event
 119  * @rport: The rport which the event has occured on
 120  * @event: The event that occured
 121  *
 122  * Locking Note: The rport lock should not be held when calling
 123  *               this function.
 124  */
 125 static void fc_disc_rport_callback(struct fc_lport *lport,
 126                                    struct fc_rport *rport,
 127                                    enum fc_rport_event event)
 128 {
 129         struct fc_rport_priv *rdata = rport->dd_data;
 130         struct fc_disc *disc = &lport->disc;
 131
 132         FC_DISC_DBG(disc, "Received a %d event for port (%6x)\n", event,
 133                     rport->port_id);
 134
 135         switch (event) {
 136         case RPORT_EV_CREATED:
 137                 if (disc) {
 138                         mutex_lock(&disc->disc_mutex);
 139                         list_add_tail(&rdata->peers, &disc->rports);
 140                         mutex_unlock(&disc->disc_mutex);
 141                 }
 142                 break;
 143         case RPORT_EV_LOGO:
 144         case RPORT_EV_FAILED:
 145         case RPORT_EV_STOP:
 146                 mutex_lock(&disc->disc_mutex);
 147                 mutex_lock(&rdata->rp_mutex);
 148                 if (rdata->trans_state == FC_PORTSTATE_ROGUE)
 149                         list_del(&rdata->peers);
 150                 mutex_unlock(&rdata->rp_mutex);
 151                 mutex_unlock(&disc->disc_mutex);
 152                 break;
 153         default:
 154                 break;
 155         }
 156
 157 }
 158
 159 /**
 160  * fc_disc_recv_rscn_req() - Handle Registered State Change Notification (RSCN)
 161  * @sp: Current sequence of the RSCN exchange
 162  * @fp: RSCN Frame
 163  * @lport: Fibre Channel host port instance
 164  *
 165  * Locking Note: This function expects that the disc_mutex is locked
 166  *               before it is called.
 167  */
 168 static void fc_disc_recv_rscn_req(struct fc_seq *sp, struct fc_frame *fp,
 169                                   struct fc_disc *disc)
 170 {
 171         struct fc_lport *lport;
 172         struct fc_rport *rport;
 173         struct fc_rport_priv *rdata;
 174         struct fc_els_rscn *rp;
 175         struct fc_els_rscn_page *pp;
 176         struct fc_seq_els_data rjt_data;
 177         unsigned int len;
 178         int redisc = 0;
 179         enum fc_els_rscn_ev_qual ev_qual;
 180         enum fc_els_rscn_addr_fmt fmt;
 181         LIST_HEAD(disc_ports);
 182         struct fc_disc_port *dp, *next;
 183
 184         lport = disc->lport;
 185
 186         FC_DISC_DBG(disc, "Received an RSCN event\n");
 187
 188         /* make sure the frame contains an RSCN message */
 189         rp = fc_frame_payload_get(fp, sizeof(*rp));
 190         if (!rp)
 191                 goto reject;
 192         /* make sure the page length is as expected (4 bytes) */
 193         if (rp->rscn_page_len != sizeof(*pp))
 194                 goto reject;
 195         /* get the RSCN payload length */
 196         len = ntohs(rp->rscn_plen);
 197         if (len < sizeof(*rp))
 198                 goto reject;
 199         /* make sure the frame contains the expected payload */
 200         rp = fc_frame_payload_get(fp, len);
 201         if (!rp)
 202                 goto reject;
 203         /* payload must be a multiple of the RSCN page size */
 204         len -= sizeof(*rp);
 205         if (len % sizeof(*pp))
 206                 goto reject;
 207
 208         for (pp = (void *)(rp + 1); len > 0; len -= sizeof(*pp), pp++) {
 209                 ev_qual = pp->rscn_page_flags >> ELS_RSCN_EV_QUAL_BIT;
 210                 ev_qual &= ELS_RSCN_EV_QUAL_MASK;
 211                 fmt = pp->rscn_page_flags >> ELS_RSCN_ADDR_FMT_BIT;
 212                 fmt &= ELS_RSCN_ADDR_FMT_MASK;
 213                 /*
 214                  * if we get an address format other than port
 215                  * (area, domain, fabric), then do a full discovery
 216                  */
 217                 switch (fmt) {
 218                 case ELS_ADDR_FMT_PORT:
 219                         FC_DISC_DBG(disc, "Port address format for port "
 220                                     "(%6x)\n", ntoh24(pp->rscn_fid));
 221                         dp = kzalloc(sizeof(*dp), GFP_KERNEL);
 222                         if (!dp) {
 223                                 redisc = 1;
 224                                 break;
 225                         }
 226                         dp->lp = lport;
 227                         dp->ids.port_id = ntoh24(pp->rscn_fid);
 228                         dp->ids.port_name = -1;
 229                         dp->ids.node_name = -1;
 230                         dp->ids.roles = FC_RPORT_ROLE_UNKNOWN;
 231                         list_add_tail(&dp->peers, &disc_ports);
 232                         break;
 233                 case ELS_ADDR_FMT_AREA:
 234                 case ELS_ADDR_FMT_DOM:
 235                 case ELS_ADDR_FMT_FAB:
 236                 default:
 237                         FC_DISC_DBG(disc, "Address format is (%d)\n", fmt);
 238                         redisc = 1;
 239                         break;
 240                 }
 241         }
 242         lport->tt.seq_els_rsp_send(sp, ELS_LS_ACC, NULL);
 243         if (redisc) {
 244                 FC_DISC_DBG(disc, "RSCN received: rediscovering\n");
 245                 fc_disc_restart(disc);
 246         } else {
 247                 FC_DISC_DBG(disc, "RSCN received: not rediscovering. "
 248                             "redisc %d state %d in_prog %d\n",
 249                             redisc, lport->state, disc->pending);
 250                 list_for_each_entry_safe(dp, next, &disc_ports, peers) {
 251                         list_del(&dp->peers);
 252                         rport = lport->tt.rport_lookup(lport, dp->ids.port_id);
 253                         if (rport) {
 254                                 rdata = rport->dd_data;
 255                                 list_del(&rdata->peers);
 256                                 lport->tt.rport_logoff(rport);
 257                         }
 258                         fc_disc_single(disc, dp);
 259                 }
 260         }
 261         fc_frame_free(fp);
 262         return;
 263 reject:
 264         FC_DISC_DBG(disc, "Received a bad RSCN frame\n");
 265         rjt_data.fp = NULL;
 266         rjt_data.reason = ELS_RJT_LOGIC;
 267         rjt_data.explan = ELS_EXPL_NONE;
 268         lport->tt.seq_els_rsp_send(sp, ELS_LS_RJT, &rjt_data);
 269         fc_frame_free(fp);
 270 }
 271
 272 /**
 273  * fc_disc_recv_req() - Handle incoming requests
 274  * @sp: Current sequence of the request exchange
 275  * @fp: The frame
 276  * @lport: The FC local port
 277  *
 278  * Locking Note: This function is called from the EM and will lock
 279  *               the disc_mutex before calling the handler for the
 280  *               request.
 281  */
 282 static void fc_disc_recv_req(struct fc_seq *sp, struct fc_frame *fp,
 283                              struct fc_lport *lport)
 284 {
 285         u8 op;
 286         struct fc_disc *disc = &lport->disc;
 287
 288         op = fc_frame_payload_op(fp);
 289         switch (op) {
 290         case ELS_RSCN:
 291                 mutex_lock(&disc->disc_mutex);
 292                 fc_disc_recv_rscn_req(sp, fp, disc);
 293                 mutex_unlock(&disc->disc_mutex);
 294                 break;
 295         default:
 296                 FC_DISC_DBG(disc, "Received an unsupported request, "
 297                             "the opcode is (%x)\n", op);
 298                 break;
 299         }
 300 }
 301
 302 /**
 303  * fc_disc_restart() - Restart discovery
 304  * @lport: FC discovery context
 305  *
 306  * Locking Note: This function expects that the disc mutex
 307  *               is already locked.
 308  */
 309 static void fc_disc_restart(struct fc_disc *disc)
 310 {
 311         struct fc_rport *rport;
 312         struct fc_rport_priv *rdata, *next;
 313         struct fc_lport *lport = disc->lport;
 314
 315         FC_DISC_DBG(disc, "Restarting discovery\n");
 316
 317         list_for_each_entry_safe(rdata, next, &disc->rports, peers) {
 318                 rport = PRIV_TO_RPORT(rdata);
 319                 list_del(&rdata->peers);
 320                 lport->tt.rport_logoff(rport);
 321         }
 322
 323         disc->requested = 1;
 324         if (!disc->pending)
 325                 fc_disc_gpn_ft_req(disc);
 326 }
 327
 328 /**
 329  * fc_disc_start() - Fibre Channel Target discovery
 330  * @lport: FC local port
 331  *
 332  * Returns non-zero if discovery cannot be started.
 333  */
 334 static void fc_disc_start(void (*disc_callback)(struct fc_lport *,
 335                                                 enum fc_disc_event),
 336                           struct fc_lport *lport)
 337 {
 338         struct fc_rport *rport;
 339         struct fc_rport_identifiers ids;
 340         struct fc_disc *disc = &lport->disc;
 341
 342         /*
 343          * At this point we may have a new disc job or an existing
 344          * one. Either way, let's lock when we make changes to it
 345          * and send the GPN_FT request.
 346          */
 347         mutex_lock(&disc->disc_mutex);
 348
 349         disc->disc_callback = disc_callback;
 350
 351         /*
 352          * If not ready, or already running discovery, just set request flag.
 353          */
 354         disc->requested = 1;
 355
 356         if (disc->pending) {
 357                 mutex_unlock(&disc->disc_mutex);
 358                 return;
 359         }
 360
 361         /*
 362          * Handle point-to-point mode as a simple discovery
 363          * of the remote port. Yucky, yucky, yuck, yuck!
 364          */
 365         rport = disc->lport->ptp_rp;
 366         if (rport) {
 367                 ids.port_id = rport->port_id;
 368                 ids.port_name = rport->port_name;
 369                 ids.node_name = rport->node_name;
 370                 ids.roles = FC_RPORT_ROLE_UNKNOWN;
 371                 get_device(&rport->dev);
 372
 373                 if (!fc_disc_new_target(disc, rport, &ids)) {
 374                         disc->event = DISC_EV_SUCCESS;
 375                         fc_disc_done(disc);
 376                 }
 377                 put_device(&rport->dev);
 378         } else {
 379                 fc_disc_gpn_ft_req(disc);       /* get ports by FC-4 type */
 380         }
 381
 382         mutex_unlock(&disc->disc_mutex);
 383 }
 384
 385 static struct fc_rport_operations fc_disc_rport_ops = {
 386         .event_callback = fc_disc_rport_callback,
 387 };
 388
 389 /**
 390  * fc_disc_new_target() - Handle new target found by discovery
 391  * @lport: FC local port
 392  * @rport: The previous FC remote port (NULL if new remote port)
 393  * @ids: Identifiers for the new FC remote port
 394  *
 395  * Locking Note: This function expects that the disc_mutex is locked
 396  *               before it is called.
 397  */
 398 static int fc_disc_new_target(struct fc_disc *disc,
 399                               struct fc_rport *rport,
 400                               struct fc_rport_identifiers *ids)
 401 {
 402         struct fc_lport *lport = disc->lport;
 403         struct fc_rport_priv *rdata;
 404         int error = 0;
 405
 406         if (rport && ids->port_name) {
 407                 if (rport->port_name == -1) {
 408                         /*
 409                          * Set WWN and fall through to notify of create.
 410                          */
 411                         fc_rport_set_name(rport, ids->port_name,
 412                                           rport->node_name);
 413                 } else if (rport->port_name != ids->port_name) {
 414                         /*
 415                          * This is a new port with the same FCID as
 416                          * a previously-discovered port.  Presumably the old
 417                          * port logged out and a new port logged in and was
 418                          * assigned the same FCID.  This should be rare.
 419                          * Delete the old one and fall thru to re-create.
 420                          */
 421                         fc_disc_del_target(disc, rport);
 422                         rport = NULL;
 423                 }
 424         }
 425         if (((ids->port_name != -1) || (ids->port_id != -1)) &&
 426             ids->port_id != fc_host_port_id(lport->host) &&
 427             ids->port_name != lport->wwpn) {
 428                 if (!rport) {
 429                         rport = lport->tt.rport_lookup(lport, ids->port_id);
 430                         if (!rport) {
 431                                 rport = lport->tt.rport_create(lport, ids);
 432                         }
 433                         if (!rport)
 434                                 error = -ENOMEM;
 435                 }
 436                 if (rport) {
 437                         rdata = rport->dd_data;
 438                         rdata->ops = &fc_disc_rport_ops;
 439                         rdata->rp_state = RPORT_ST_INIT;
 440                         list_add_tail(&rdata->peers, &disc->rogue_rports);
 441                         lport->tt.rport_login(rport);
 442                 }
 443         }
 444         return error;
 445 }
 446
 447 /**
 448  * fc_disc_del_target() - Delete a target
 449  * @disc: FC discovery context
 450  * @rport: The remote port to be removed
 451  */
 452 static void fc_disc_del_target(struct fc_disc *disc, struct fc_rport *rport)
 453 {
 454         struct fc_lport *lport = disc->lport;
 455         struct fc_rport_priv *rdata = rport->dd_data;
 456         list_del(&rdata->peers);
 457         lport->tt.rport_logoff(rport);
 458 }
 459
 460 /**
 461  * fc_disc_done() - Discovery has been completed
 462  * @disc: FC discovery context
 463  * Locking Note: This function expects that the disc mutex is locked before
 464  * it is called. The discovery callback is then made with the lock released,
 465  * and the lock is re-taken before returning from this function
 466  */
 467 static void fc_disc_done(struct fc_disc *disc)
 468 {
 469         struct fc_lport *lport = disc->lport;
 470         enum fc_disc_event event;
 471
 472         FC_DISC_DBG(disc, "Discovery complete\n");
 473
 474         event = disc->event;
 475         disc->event = DISC_EV_NONE;
 476
 477         if (disc->requested)
 478                 fc_disc_gpn_ft_req(disc);
 479         else
 480                 disc->pending = 0;
 481
 482         mutex_unlock(&disc->disc_mutex);
 483         disc->disc_callback(lport, event);
 484         mutex_lock(&disc->disc_mutex);
 485 }
 486
 487 /**
 488  * fc_disc_error() - Handle error on dNS request
 489  * @disc: FC discovery context
 490  * @fp: The frame pointer
 491  */
 492 static void fc_disc_error(struct fc_disc *disc, struct fc_frame *fp)
 493 {
 494         struct fc_lport *lport = disc->lport;
 495         unsigned long delay = 0;
 496
 497         FC_DISC_DBG(disc, "Error %ld, retries %d/%d\n",
 498                     PTR_ERR(fp), disc->retry_count,
 499                     FC_DISC_RETRY_LIMIT);
 500
 501         if (!fp || PTR_ERR(fp) == -FC_EX_TIMEOUT) {
 502                 /*
 503                  * Memory allocation failure, or the exchange timed out,
 504                  * retry after delay.
 505                  */
 506                 if (disc->retry_count < FC_DISC_RETRY_LIMIT) {
 507                         /* go ahead and retry */
 508                         if (!fp)
 509                                 delay = msecs_to_jiffies(FC_DISC_RETRY_DELAY);
 510                         else {
 511                                 delay = msecs_to_jiffies(lport->e_d_tov);
 512
 513                                 /* timeout faster first time */
 514                                 if (!disc->retry_count)
 515                                         delay /= 4;
 516                         }
 517                         disc->retry_count++;
 518                         schedule_delayed_work(&disc->disc_work, delay);
 519                 } else {
 520                         /* exceeded retries */
 521                         disc->event = DISC_EV_FAILED;
 522                         fc_disc_done(disc);
 523                 }
 524         }
 525 }
 526
 527 /**
 528  * fc_disc_gpn_ft_req() - Send Get Port Names by FC-4 type (GPN_FT) request
 529  * @lport: FC discovery context
 530  *
 531  * Locking Note: This function expects that the disc_mutex is locked
 532  *               before it is called.
 533  */
 534 static void fc_disc_gpn_ft_req(struct fc_disc *disc)
 535 {
 536         struct fc_frame *fp;
 537         struct fc_lport *lport = disc->lport;
 538
 539         WARN_ON(!fc_lport_test_ready(lport));
 540
 541         disc->pending = 1;
 542         disc->requested = 0;
 543
 544         disc->buf_len = 0;
 545         disc->seq_count = 0;
 546         fp = fc_frame_alloc(lport,
 547                             sizeof(struct fc_ct_hdr) +
 548                             sizeof(struct fc_ns_gid_ft));
 549         if (!fp)
 550                 goto err;
 551
 552         if (lport->tt.elsct_send(lport, NULL, fp,
 553                                  FC_NS_GPN_FT,
 554                                  fc_disc_gpn_ft_resp,
 555                                  disc, lport->e_d_tov))
 556                 return;
 557 err:
 558         fc_disc_error(disc, fp);
 559 }
 560
 561 /**
 562  * fc_disc_gpn_ft_parse() - Parse the list of IDs and names resulting from a request
 563  * @lport: Fibre Channel host port instance
 564  * @buf: GPN_FT response buffer
 565  * @len: size of response buffer
 566  */
 567 static int fc_disc_gpn_ft_parse(struct fc_disc *disc, void *buf, size_t len)
 568 {
 569         struct fc_lport *lport;
 570         struct fc_gpn_ft_resp *np;
 571         char *bp;
 572         size_t plen;
 573         size_t tlen;
 574         int error = 0;
 575         struct fc_rport_identifiers ids;
 576         struct fc_rport *rport;
 577         struct fc_rport_priv *rdata;
 578
 579         lport = disc->lport;
 580
 581         /*
 582          * Handle partial name record left over from previous call.
 583          */
 584         bp = buf;
 585         plen = len;
 586         np = (struct fc_gpn_ft_resp *)bp;
 587         tlen = disc->buf_len;
 588         if (tlen) {
 589                 WARN_ON(tlen >= sizeof(*np));
 590                 plen = sizeof(*np) - tlen;
 591                 WARN_ON(plen <= 0);
 592                 WARN_ON(plen >= sizeof(*np));
 593                 if (plen > len)
 594                         plen = len;
 595                 np = &disc->partial_buf;
 596                 memcpy((char *)np + tlen, bp, plen);
 597
 598                 /*
 599                  * Set bp so that the loop below will advance it to the
 600                  * first valid full name element.
 601                  */
 602                 bp -= tlen;
 603                 len += tlen;
 604                 plen += tlen;
 605                 disc->buf_len = (unsigned char) plen;
 606                 if (plen == sizeof(*np))
 607                         disc->buf_len = 0;
 608         }
 609
 610         /*
 611          * Handle full name records, including the one filled from above.
 612          * Normally, np == bp and plen == len, but from the partial case above,
 613          * bp, len describe the overall buffer, and np, plen describe the
 614          * partial buffer, which if would usually be full now.
 615          * After the first time through the loop, things return to "normal".
 616          */
 617         while (plen >= sizeof(*np)) {
 618                 ids.port_id = ntoh24(np->fp_fid);
 619                 ids.port_name = ntohll(np->fp_wwpn);
 620                 ids.node_name = -1;
 621                 ids.roles = FC_RPORT_ROLE_UNKNOWN;
 622
 623                 if (ids.port_id != fc_host_port_id(lport->host) &&
 624                     ids.port_name != lport->wwpn) {
 625                         rport = lport->tt.rport_create(lport, &ids);
 626                         if (rport) {
 627                                 rdata = rport->dd_data;
 628                                 rdata->ops = &fc_disc_rport_ops;
 629                                 rdata->local_port = lport;
 630                                 list_add_tail(&rdata->peers,
 631                                               &disc->rogue_rports);
 632                                 lport->tt.rport_login(rport);
 633                         } else
 634                                 printk(KERN_WARNING "libfc: Failed to allocate "
 635                                        "memory for the newly discovered port "
 636                                        "(%6x)\n", ids.port_id);
 637                 }
 638
 639                 if (np->fp_flags & FC_NS_FID_LAST) {
 640                         disc->event = DISC_EV_SUCCESS;
 641                         fc_disc_done(disc);
 642                         len = 0;
 643                         break;
 644                 }
 645                 len -= sizeof(*np);
 646                 bp += sizeof(*np);
 647                 np = (struct fc_gpn_ft_resp *)bp;
 648                 plen = len;
 649         }
 650
 651         /*
 652          * Save any partial record at the end of the buffer for next time.
 653          */
 654         if (error == 0 && len > 0 && len < sizeof(*np)) {
 655                 if (np != &disc->partial_buf) {
 656                         FC_DISC_DBG(disc, "Partial buffer remains "
 657                                     "for discovery\n");
 658                         memcpy(&disc->partial_buf, np, len);
 659                 }
 660                 disc->buf_len = (unsigned char) len;
 661         } else {
 662                 disc->buf_len = 0;
 663         }
 664         return error;
 665 }
 666
 667 /**
 668  * fc_disc_timeout() - Retry handler for the disc component
 669  * @work: Structure holding disc obj that needs retry discovery
 670  *
 671  * Handle retry of memory allocation for remote ports.
 672  */
 673 static void fc_disc_timeout(struct work_struct *work)
 674 {
 675         struct fc_disc *disc = container_of(work,
 676                                             struct fc_disc,
 677                                             disc_work.work);
 678         mutex_lock(&disc->disc_mutex);
 679         if (disc->requested && !disc->pending)
 680                 fc_disc_gpn_ft_req(disc);
 681         mutex_unlock(&disc->disc_mutex);
 682 }
 683
 684 /**
 685  * fc_disc_gpn_ft_resp() - Handle a response frame from Get Port Names (GPN_FT)
 686  * @sp: Current sequence of GPN_FT exchange
 687  * @fp: response frame
 688  * @lp_arg: Fibre Channel host port instance
 689  *
 690  * Locking Note: This function is called without disc mutex held, and
 691  *               should do all its processing with the mutex held
 692  */
 693 static void fc_disc_gpn_ft_resp(struct fc_seq *sp, struct fc_frame *fp,
 694                                 void *disc_arg)
 695 {
 696         struct fc_disc *disc = disc_arg;
 697         struct fc_ct_hdr *cp;
 698         struct fc_frame_header *fh;
 699         unsigned int seq_cnt;
 700         void *buf = NULL;
 701         unsigned int len;
 702         int error;
 703
 704         mutex_lock(&disc->disc_mutex);
 705         FC_DISC_DBG(disc, "Received a GPN_FT response\n");
 706
 707         if (IS_ERR(fp)) {
 708                 fc_disc_error(disc, fp);
 709                 mutex_unlock(&disc->disc_mutex);
 710                 return;
 711         }
 712
 713         WARN_ON(!fc_frame_is_linear(fp));       /* buffer must be contiguous */
 714         fh = fc_frame_header_get(fp);
 715         len = fr_len(fp) - sizeof(*fh);
 716         seq_cnt = ntohs(fh->fh_seq_cnt);
 717         if (fr_sof(fp) == FC_SOF_I3 && seq_cnt == 0 &&
 718             disc->seq_count == 0) {
 719                 cp = fc_frame_payload_get(fp, sizeof(*cp));
 720                 if (!cp) {
 721                         FC_DISC_DBG(disc, "GPN_FT response too short, len %d\n",
 722                                     fr_len(fp));
 723                 } else if (ntohs(cp->ct_cmd) == FC_FS_ACC) {
 724
 725                         /* Accepted, parse the response. */
 726                         buf = cp + 1;
 727                         len -= sizeof(*cp);
 728                 } else if (ntohs(cp->ct_cmd) == FC_FS_RJT) {
 729                         FC_DISC_DBG(disc, "GPN_FT rejected reason %x exp %x "
 730                                     "(check zoning)\n", cp->ct_reason,
 731                                     cp->ct_explan);
 732                         disc->event = DISC_EV_FAILED;
 733                         fc_disc_done(disc);
 734                 } else {
 735                         FC_DISC_DBG(disc, "GPN_FT unexpected response code "
 736                                     "%x\n", ntohs(cp->ct_cmd));
 737                 }
 738         } else if (fr_sof(fp) == FC_SOF_N3 &&
 739                    seq_cnt == disc->seq_count) {
 740                 buf = fh + 1;
 741         } else {
 742                 FC_DISC_DBG(disc, "GPN_FT unexpected frame - out of sequence? "
 743                             "seq_cnt %x expected %x sof %x eof %x\n",
 744                             seq_cnt, disc->seq_count, fr_sof(fp), fr_eof(fp));
 745         }
 746         if (buf) {
 747                 error = fc_disc_gpn_ft_parse(disc, buf, len);
 748                 if (error)
 749                         fc_disc_error(disc, fp);
 750                 else
 751                         disc->seq_count++;
 752         }
 753         fc_frame_free(fp);
 754
 755         mutex_unlock(&disc->disc_mutex);
 756 }
 757
 758 /**
 759  * fc_disc_single() - Discover the directory information for a single target
 760  * @lport: FC local port
 761  * @dp: The port to rediscover
 762  *
 763  * Locking Note: This function expects that the disc_mutex is locked
 764  *               before it is called.
 765  */
 766 static void fc_disc_single(struct fc_disc *disc, struct fc_disc_port *dp)
 767 {
 768         struct fc_lport *lport;
 769         struct fc_rport *new_rport;
 770         struct fc_rport_priv *rdata;
 771
 772         lport = disc->lport;
 773
 774         if (dp->ids.port_id == fc_host_port_id(lport->host))
 775                 goto out;
 776
 777         new_rport = lport->tt.rport_create(lport, &dp->ids);
 778         if (new_rport) {
 779                 rdata = new_rport->dd_data;
 780                 rdata->ops = &fc_disc_rport_ops;
 781                 kfree(dp);
 782                 list_add_tail(&rdata->peers, &disc->rogue_rports);
 783                 lport->tt.rport_login(new_rport);
 784         }
 785         return;
 786 out:
 787         kfree(dp);
 788 }
 789
 790 /**
 791  * fc_disc_stop() - Stop discovery for a given lport
 792  * @lport: The lport that discovery should stop for
 793  */
 794 void fc_disc_stop(struct fc_lport *lport)
 795 {
 796         struct fc_disc *disc = &lport->disc;
 797
 798         if (disc) {
 799                 cancel_delayed_work_sync(&disc->disc_work);
 800                 fc_disc_stop_rports(disc);
 801         }
 802 }
 803
 804 /**
 805  * fc_disc_stop_final() - Stop discovery for a given lport
 806  * @lport: The lport that discovery should stop for
 807  *
 808  * This function will block until discovery has been
 809  * completely stopped and all rports have been deleted.
 810  */
 811 void fc_disc_stop_final(struct fc_lport *lport)
 812 {
 813         fc_disc_stop(lport);
 814         lport->tt.rport_flush_queue();
 815 }
 816
 817 /**
 818  * fc_disc_init() - Initialize the discovery block
 819  * @lport: FC local port
 820  */
 821 int fc_disc_init(struct fc_lport *lport)
 822 {
 823         struct fc_disc *disc;
 824
 825         if (!lport->tt.disc_start)
 826                 lport->tt.disc_start = fc_disc_start;
 827
 828         if (!lport->tt.disc_stop)
 829                 lport->tt.disc_stop = fc_disc_stop;
 830
 831         if (!lport->tt.disc_stop_final)
 832                 lport->tt.disc_stop_final = fc_disc_stop_final;
 833
 834         if (!lport->tt.disc_recv_req)
 835                 lport->tt.disc_recv_req = fc_disc_recv_req;
 836
 837         if (!lport->tt.rport_lookup)
 838                 lport->tt.rport_lookup = fc_disc_lookup_rport;
 839
 840         disc = &lport->disc;
 841         INIT_DELAYED_WORK(&disc->disc_work, fc_disc_timeout);
 842         mutex_init(&disc->disc_mutex);
 843         INIT_LIST_HEAD(&disc->rports);
 844         INIT_LIST_HEAD(&disc->rogue_rports);
 845
 846         disc->lport = lport;
 847         disc->delay = FC_DISC_DELAY;
 848         disc->event = DISC_EV_NONE;
 849
 850         return 0;
 851 }
 852 EXPORT_SYMBOL(fc_disc_init);