drivers/scsi/libfc/fc_disc.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright(c) 2007 - 2008 Intel Corporation. All rights reserved.
   4  *
   5  * Maintained at www.Open-FCoE.org
   6  */
   7
   8 /*
   9  * Target Discovery
  10  *
  11  * This block discovers all FC-4 remote ports, including FCP initiators. It
  12  * also handles RSCN events and re-discovery if necessary.
  13  */
  14
  15 /*
  16  * DISC LOCKING
  17  *
  18  * The disc mutex is can be locked when acquiring rport locks, but may not
  19  * be held when acquiring the lport lock. Refer to fc_lport.c for more
  20  * details.
  21  */
  22
  23 #include <linux/timer.h>
  24 #include <linux/slab.h>
  25 #include <linux/err.h>
  26 #include <linux/export.h>
  27 #include <linux/list.h>
  28
  29 #include <linux/unaligned.h>
  30
  31 #include <scsi/fc/fc_gs.h>
  32
  33 #include <scsi/libfc.h>
  34
  35 #include "fc_libfc.h"
  36
  37 #define FC_DISC_RETRY_LIMIT     3       /* max retries */
  38 #define FC_DISC_RETRY_DELAY     500UL   /* (msecs) delay */
  39
  40 static void fc_disc_gpn_ft_req(struct fc_disc *);
  41 static void fc_disc_gpn_ft_resp(struct fc_seq *, struct fc_frame *, void *);
  42 static void fc_disc_done(struct fc_disc *, enum fc_disc_event);
  43 static void fc_disc_timeout(struct work_struct *);
  44 static int fc_disc_single(struct fc_lport *, struct fc_disc_port *);
  45 static void fc_disc_restart(struct fc_disc *);
  46
  47 /**
  48  * fc_disc_stop_rports() - Delete all the remote ports associated with the lport
  49  * @disc: The discovery job to stop remote ports on
  50  */
  51 static void fc_disc_stop_rports(struct fc_disc *disc)
  52 {
  53         struct fc_rport_priv *rdata;
  54
  55         lockdep_assert_held(&disc->disc_mutex);
  56
  57         list_for_each_entry(rdata, &disc->rports, peers) {
  58                 if (kref_get_unless_zero(&rdata->kref)) {
  59                         fc_rport_logoff(rdata);
  60                         kref_put(&rdata->kref, fc_rport_destroy);
  61                 }
  62         }
  63 }
  64
  65 /**
  66  * fc_disc_recv_rscn_req() - Handle Registered State Change Notification (RSCN)
  67  * @disc:  The discovery object to which the RSCN applies
  68  * @fp:    The RSCN frame
  69  */
  70 static void fc_disc_recv_rscn_req(struct fc_disc *disc, struct fc_frame *fp)
  71 {
  72         struct fc_lport *lport;
  73         struct fc_els_rscn *rp;
  74         struct fc_els_rscn_page *pp;
  75         struct fc_seq_els_data rjt_data;
  76         unsigned int len;
  77         int redisc = 0;
  78         enum fc_els_rscn_addr_fmt fmt;
  79         LIST_HEAD(disc_ports);
  80         struct fc_disc_port *dp, *next;
  81
  82         lockdep_assert_held(&disc->disc_mutex);
  83
  84         lport = fc_disc_lport(disc);
  85
  86         FC_DISC_DBG(disc, "Received an RSCN event\n");
  87
  88         /* make sure the frame contains an RSCN message */
  89         rp = fc_frame_payload_get(fp, sizeof(*rp));
  90         if (!rp)
  91                 goto reject;
  92         /* make sure the page length is as expected (4 bytes) */
  93         if (rp->rscn_page_len != sizeof(*pp))
  94                 goto reject;
  95         /* get the RSCN payload length */
  96         len = ntohs(rp->rscn_plen);
  97         if (len < sizeof(*rp))
  98                 goto reject;
  99         /* make sure the frame contains the expected payload */
 100         rp = fc_frame_payload_get(fp, len);
 101         if (!rp)
 102                 goto reject;
 103         /* payload must be a multiple of the RSCN page size */
 104         len -= sizeof(*rp);
 105         if (len % sizeof(*pp))
 106                 goto reject;
 107
 108         for (pp = (void *)(rp + 1); len > 0; len -= sizeof(*pp), pp++) {
 109                 fmt = pp->rscn_page_flags >> ELS_RSCN_ADDR_FMT_BIT;
 110                 fmt &= ELS_RSCN_ADDR_FMT_MASK;
 111                 /*
 112                  * if we get an address format other than port
 113                  * (area, domain, fabric), then do a full discovery
 114                  */
 115                 switch (fmt) {
 116                 case ELS_ADDR_FMT_PORT:
 117                         FC_DISC_DBG(disc, "Port address format for port "
 118                                     "(%6.6x)\n", ntoh24(pp->rscn_fid));
 119                         dp = kzalloc(sizeof(*dp), GFP_KERNEL);
 120                         if (!dp) {
 121                                 redisc = 1;
 122                                 break;
 123                         }
 124                         dp->lp = lport;
 125                         dp->port_id = ntoh24(pp->rscn_fid);
 126                         list_add_tail(&dp->peers, &disc_ports);
 127                         break;
 128                 case ELS_ADDR_FMT_AREA:
 129                 case ELS_ADDR_FMT_DOM:
 130                 case ELS_ADDR_FMT_FAB:
 131                 default:
 132                         FC_DISC_DBG(disc, "Address format is (%d)\n", fmt);
 133                         redisc = 1;
 134                         break;
 135                 }
 136         }
 137         fc_seq_els_rsp_send(fp, ELS_LS_ACC, NULL);
 138
 139         /*
 140          * If not doing a complete rediscovery, do GPN_ID on
 141          * the individual ports mentioned in the list.
 142          * If any of these get an error, do a full rediscovery.
 143          * In any case, go through the list and free the entries.
 144          */
 145         list_for_each_entry_safe(dp, next, &disc_ports, peers) {
 146                 list_del(&dp->peers);
 147                 if (!redisc)
 148                         redisc = fc_disc_single(lport, dp);
 149                 kfree(dp);
 150         }
 151         if (redisc) {
 152                 FC_DISC_DBG(disc, "RSCN received: rediscovering\n");
 153                 fc_disc_restart(disc);
 154         } else {
 155                 FC_DISC_DBG(disc, "RSCN received: not rediscovering. "
 156                             "redisc %d state %d in_prog %d\n",
 157                             redisc, lport->state, disc->pending);
 158         }
 159         fc_frame_free(fp);
 160         return;
 161 reject:
 162         FC_DISC_DBG(disc, "Received a bad RSCN frame\n");
 163         rjt_data.reason = ELS_RJT_LOGIC;
 164         rjt_data.explan = ELS_EXPL_NONE;
 165         fc_seq_els_rsp_send(fp, ELS_LS_RJT, &rjt_data);
 166         fc_frame_free(fp);
 167 }
 168
 169 /**
 170  * fc_disc_recv_req() - Handle incoming requests
 171  * @lport: The local port receiving the request
 172  * @fp:    The request frame
 173  *
 174  * Locking Note: This function is called from the EM and will lock
 175  *               the disc_mutex before calling the handler for the
 176  *               request.
 177  */
 178 static void fc_disc_recv_req(struct fc_lport *lport, struct fc_frame *fp)
 179 {
 180         u8 op;
 181         struct fc_disc *disc = &lport->disc;
 182
 183         op = fc_frame_payload_op(fp);
 184         switch (op) {
 185         case ELS_RSCN:
 186                 mutex_lock(&disc->disc_mutex);
 187                 fc_disc_recv_rscn_req(disc, fp);
 188                 mutex_unlock(&disc->disc_mutex);
 189                 break;
 190         default:
 191                 FC_DISC_DBG(disc, "Received an unsupported request, "
 192                             "the opcode is (%x)\n", op);
 193                 fc_frame_free(fp);
 194                 break;
 195         }
 196 }
 197
 198 /**
 199  * fc_disc_restart() - Restart discovery
 200  * @disc: The discovery object to be restarted
 201  */
 202 static void fc_disc_restart(struct fc_disc *disc)
 203 {
 204         lockdep_assert_held(&disc->disc_mutex);
 205
 206         if (!disc->disc_callback)
 207                 return;
 208
 209         FC_DISC_DBG(disc, "Restarting discovery\n");
 210
 211         disc->requested = 1;
 212         if (disc->pending)
 213                 return;
 214
 215         /*
 216          * Advance disc_id.  This is an arbitrary non-zero number that will
 217          * match the value in the fc_rport_priv after discovery for all
 218          * freshly-discovered remote ports.  Avoid wrapping to zero.
 219          */
 220         disc->disc_id = (disc->disc_id + 2) | 1;
 221         disc->retry_count = 0;
 222         fc_disc_gpn_ft_req(disc);
 223 }
 224
 225 /**
 226  * fc_disc_start() - Start discovery on a local port
 227  * @lport:         The local port to have discovery started on
 228  * @disc_callback: Callback function to be called when discovery is complete
 229  */
 230 static void fc_disc_start(void (*disc_callback)(struct fc_lport *,
 231                                                 enum fc_disc_event),
 232                           struct fc_lport *lport)
 233 {
 234         struct fc_disc *disc = &lport->disc;
 235
 236         /*
 237          * At this point we may have a new disc job or an existing
 238          * one. Either way, let's lock when we make changes to it
 239          * and send the GPN_FT request.
 240          */
 241         mutex_lock(&disc->disc_mutex);
 242         disc->disc_callback = disc_callback;
 243         fc_disc_restart(disc);
 244         mutex_unlock(&disc->disc_mutex);
 245 }
 246
 247 /**
 248  * fc_disc_done() - Discovery has been completed
 249  * @disc:  The discovery context
 250  * @event: The discovery completion status
 251  */
 252 static void fc_disc_done(struct fc_disc *disc, enum fc_disc_event event)
 253 {
 254         struct fc_lport *lport = fc_disc_lport(disc);
 255         struct fc_rport_priv *rdata;
 256
 257         lockdep_assert_held(&disc->disc_mutex);
 258         FC_DISC_DBG(disc, "Discovery complete\n");
 259
 260         disc->pending = 0;
 261         if (disc->requested) {
 262                 fc_disc_restart(disc);
 263                 return;
 264         }
 265
 266         /*
 267          * Go through all remote ports.  If they were found in the latest
 268          * discovery, reverify or log them in.  Otherwise, log them out.
 269          * Skip ports which were never discovered.  These are the dNS port
 270          * and ports which were created by PLOGI.
 271          *
 272          * We don't need to use the _rcu variant here as the rport list
 273          * is protected by the disc mutex which is already held on entry.
 274          */
 275         list_for_each_entry(rdata, &disc->rports, peers) {
 276                 if (!kref_get_unless_zero(&rdata->kref))
 277                         continue;
 278                 if (rdata->disc_id) {
 279                         if (rdata->disc_id == disc->disc_id)
 280                                 fc_rport_login(rdata);
 281                         else
 282                                 fc_rport_logoff(rdata);
 283                 }
 284                 kref_put(&rdata->kref, fc_rport_destroy);
 285         }
 286         mutex_unlock(&disc->disc_mutex);
 287         disc->disc_callback(lport, event);
 288         mutex_lock(&disc->disc_mutex);
 289 }
 290
 291 /**
 292  * fc_disc_error() - Handle error on dNS request
 293  * @disc: The discovery context
 294  * @fp:   The error code encoded as a frame pointer
 295  */
 296 static void fc_disc_error(struct fc_disc *disc, struct fc_frame *fp)
 297 {
 298         struct fc_lport *lport = fc_disc_lport(disc);
 299         unsigned long delay = 0;
 300
 301         FC_DISC_DBG(disc, "Error %d, retries %d/%d\n",
 302                     PTR_ERR_OR_ZERO(fp), disc->retry_count,
 303                     FC_DISC_RETRY_LIMIT);
 304
 305         if (!fp || PTR_ERR(fp) == -FC_EX_TIMEOUT) {
 306                 /*
 307                  * Memory allocation failure, or the exchange timed out,
 308                  * retry after delay.
 309                  */
 310                 if (disc->retry_count < FC_DISC_RETRY_LIMIT) {
 311                         /* go ahead and retry */
 312                         if (!fp)
 313                                 delay = msecs_to_jiffies(FC_DISC_RETRY_DELAY);
 314                         else {
 315                                 delay = msecs_to_jiffies(lport->e_d_tov);
 316
 317                                 /* timeout faster first time */
 318                                 if (!disc->retry_count)
 319                                         delay /= 4;
 320                         }
 321                         disc->retry_count++;
 322                         schedule_delayed_work(&disc->disc_work, delay);
 323                 } else
 324                         fc_disc_done(disc, DISC_EV_FAILED);
 325         } else if (PTR_ERR(fp) == -FC_EX_CLOSED) {
 326                 /*
 327                  * if discovery fails due to lport reset, clear
 328                  * pending flag so that subsequent discovery can
 329                  * continue
 330                  */
 331                 disc->pending = 0;
 332         }
 333 }
 334
 335 /**
 336  * fc_disc_gpn_ft_req() - Send Get Port Names by FC-4 type (GPN_FT) request
 337  * @disc: The discovery context
 338  */
 339 static void fc_disc_gpn_ft_req(struct fc_disc *disc)
 340 {
 341         struct fc_frame *fp;
 342         struct fc_lport *lport = fc_disc_lport(disc);
 343
 344         lockdep_assert_held(&disc->disc_mutex);
 345
 346         WARN_ON(!fc_lport_test_ready(lport));
 347
 348         disc->pending = 1;
 349         disc->requested = 0;
 350
 351         disc->buf_len = 0;
 352         disc->seq_count = 0;
 353         fp = fc_frame_alloc(lport,
 354                             sizeof(struct fc_ct_hdr) +
 355                             sizeof(struct fc_ns_gid_ft));
 356         if (!fp)
 357                 goto err;
 358
 359         if (lport->tt.elsct_send(lport, 0, fp,
 360                                  FC_NS_GPN_FT,
 361                                  fc_disc_gpn_ft_resp,
 362                                  disc, 3 * lport->r_a_tov))
 363                 return;
 364 err:
 365         fc_disc_error(disc, NULL);
 366 }
 367
 368 /**
 369  * fc_disc_gpn_ft_parse() - Parse the body of the dNS GPN_FT response.
 370  * @disc:  The discovery context
 371  * @buf:   The GPN_FT response buffer
 372  * @len:   The size of response buffer
 373  *
 374  * Goes through the list of IDs and names resulting from a request.
 375  */
 376 static int fc_disc_gpn_ft_parse(struct fc_disc *disc, void *buf, size_t len)
 377 {
 378         struct fc_lport *lport;
 379         struct fc_gpn_ft_resp *np;
 380         char *bp;
 381         size_t plen;
 382         size_t tlen;
 383         int error = 0;
 384         struct fc_rport_identifiers ids;
 385         struct fc_rport_priv *rdata;
 386
 387         lport = fc_disc_lport(disc);
 388         disc->seq_count++;
 389
 390         /*
 391          * Handle partial name record left over from previous call.
 392          */
 393         bp = buf;
 394         plen = len;
 395         np = (struct fc_gpn_ft_resp *)bp;
 396         tlen = disc->buf_len;
 397         disc->buf_len = 0;
 398         if (tlen) {
 399                 WARN_ON(tlen >= sizeof(*np));
 400                 plen = sizeof(*np) - tlen;
 401                 WARN_ON(plen <= 0);
 402                 WARN_ON(plen >= sizeof(*np));
 403                 if (plen > len)
 404                         plen = len;
 405                 np = &disc->partial_buf;
 406                 memcpy((char *)np + tlen, bp, plen);
 407
 408                 /*
 409                  * Set bp so that the loop below will advance it to the
 410                  * first valid full name element.
 411                  */
 412                 bp -= tlen;
 413                 len += tlen;
 414                 plen += tlen;
 415                 disc->buf_len = (unsigned char) plen;
 416                 if (plen == sizeof(*np))
 417                         disc->buf_len = 0;
 418         }
 419
 420         /*
 421          * Handle full name records, including the one filled from above.
 422          * Normally, np == bp and plen == len, but from the partial case above,
 423          * bp, len describe the overall buffer, and np, plen describe the
 424          * partial buffer, which if would usually be full now.
 425          * After the first time through the loop, things return to "normal".
 426          */
 427         while (plen >= sizeof(*np)) {
 428                 ids.port_id = ntoh24(np->fp_fid);
 429                 ids.port_name = ntohll(np->fp_wwpn);
 430
 431                 if (ids.port_id != lport->port_id &&
 432                     ids.port_name != lport->wwpn) {
 433                         rdata = fc_rport_create(lport, ids.port_id);
 434                         if (rdata) {
 435                                 rdata->ids.port_name = ids.port_name;
 436                                 rdata->disc_id = disc->disc_id;
 437                         } else {
 438                                 printk(KERN_WARNING "libfc: Failed to allocate "
 439                                        "memory for the newly discovered port "
 440                                        "(%6.6x)\n", ids.port_id);
 441                                 error = -ENOMEM;
 442                         }
 443                 }
 444
 445                 if (np->fp_flags & FC_NS_FID_LAST) {
 446                         fc_disc_done(disc, DISC_EV_SUCCESS);
 447                         len = 0;
 448                         break;
 449                 }
 450                 len -= sizeof(*np);
 451                 bp += sizeof(*np);
 452                 np = (struct fc_gpn_ft_resp *)bp;
 453                 plen = len;
 454         }
 455
 456         /*
 457          * Save any partial record at the end of the buffer for next time.
 458          */
 459         if (error == 0 && len > 0 && len < sizeof(*np)) {
 460                 if (np != &disc->partial_buf) {
 461                         FC_DISC_DBG(disc, "Partial buffer remains "
 462                                     "for discovery\n");
 463                         memcpy(&disc->partial_buf, np, len);
 464                 }
 465                 disc->buf_len = (unsigned char) len;
 466         }
 467         return error;
 468 }
 469
 470 /**
 471  * fc_disc_timeout() - Handler for discovery timeouts
 472  * @work: Structure holding discovery context that needs to retry discovery
 473  */
 474 static void fc_disc_timeout(struct work_struct *work)
 475 {
 476         struct fc_disc *disc = container_of(work,
 477                                             struct fc_disc,
 478                                             disc_work.work);
 479         mutex_lock(&disc->disc_mutex);
 480         fc_disc_gpn_ft_req(disc);
 481         mutex_unlock(&disc->disc_mutex);
 482 }
 483
 484 /**
 485  * fc_disc_gpn_ft_resp() - Handle a response frame from Get Port Names (GPN_FT)
 486  * @sp:     The sequence that the GPN_FT response was received on
 487  * @fp:     The GPN_FT response frame
 488  * @disc_arg: The discovery context
 489  *
 490  * Locking Note: This function is called without disc mutex held, and
 491  *               should do all its processing with the mutex held
 492  */
 493 static void fc_disc_gpn_ft_resp(struct fc_seq *sp, struct fc_frame *fp,
 494                                 void *disc_arg)
 495 {
 496         struct fc_disc *disc = disc_arg;
 497         struct fc_ct_hdr *cp;
 498         struct fc_frame_header *fh;
 499         enum fc_disc_event event = DISC_EV_NONE;
 500         unsigned int seq_cnt;
 501         unsigned int len;
 502         int error = 0;
 503
 504         mutex_lock(&disc->disc_mutex);
 505         FC_DISC_DBG(disc, "Received a GPN_FT response\n");
 506
 507         if (IS_ERR(fp)) {
 508                 fc_disc_error(disc, fp);
 509                 mutex_unlock(&disc->disc_mutex);
 510                 return;
 511         }
 512
 513         WARN_ON(!fc_frame_is_linear(fp));       /* buffer must be contiguous */
 514         fh = fc_frame_header_get(fp);
 515         len = fr_len(fp) - sizeof(*fh);
 516         seq_cnt = ntohs(fh->fh_seq_cnt);
 517         if (fr_sof(fp) == FC_SOF_I3 && seq_cnt == 0 && disc->seq_count == 0) {
 518                 cp = fc_frame_payload_get(fp, sizeof(*cp));
 519                 if (!cp) {
 520                         FC_DISC_DBG(disc, "GPN_FT response too short, len %d\n",
 521                                     fr_len(fp));
 522                         event = DISC_EV_FAILED;
 523                 } else if (ntohs(cp->ct_cmd) == FC_FS_ACC) {
 524
 525                         /* Accepted, parse the response. */
 526                         len -= sizeof(*cp);
 527                         error = fc_disc_gpn_ft_parse(disc, cp + 1, len);
 528                 } else if (ntohs(cp->ct_cmd) == FC_FS_RJT) {
 529                         FC_DISC_DBG(disc, "GPN_FT rejected reason %x exp %x "
 530                                     "(check zoning)\n", cp->ct_reason,
 531                                     cp->ct_explan);
 532                         event = DISC_EV_FAILED;
 533                         if (cp->ct_reason == FC_FS_RJT_UNABL &&
 534                             cp->ct_explan == FC_FS_EXP_FTNR)
 535                                 event = DISC_EV_SUCCESS;
 536                 } else {
 537                         FC_DISC_DBG(disc, "GPN_FT unexpected response code "
 538                                     "%x\n", ntohs(cp->ct_cmd));
 539                         event = DISC_EV_FAILED;
 540                 }
 541         } else if (fr_sof(fp) == FC_SOF_N3 && seq_cnt == disc->seq_count) {
 542                 error = fc_disc_gpn_ft_parse(disc, fh + 1, len);
 543         } else {
 544                 FC_DISC_DBG(disc, "GPN_FT unexpected frame - out of sequence? "
 545                             "seq_cnt %x expected %x sof %x eof %x\n",
 546                             seq_cnt, disc->seq_count, fr_sof(fp), fr_eof(fp));
 547                 event = DISC_EV_FAILED;
 548         }
 549         if (error)
 550                 fc_disc_error(disc, ERR_PTR(error));
 551         else if (event != DISC_EV_NONE)
 552                 fc_disc_done(disc, event);
 553         fc_frame_free(fp);
 554         mutex_unlock(&disc->disc_mutex);
 555 }
 556
 557 /**
 558  * fc_disc_gpn_id_resp() - Handle a response frame from Get Port Names (GPN_ID)
 559  * @sp:        The sequence the GPN_ID is on
 560  * @fp:        The response frame
 561  * @rdata_arg: The remote port that sent the GPN_ID response
 562  *
 563  * Locking Note: This function is called without disc mutex held.
 564  */
 565 static void fc_disc_gpn_id_resp(struct fc_seq *sp, struct fc_frame *fp,
 566                                 void *rdata_arg)
 567 {
 568         struct fc_rport_priv *rdata = rdata_arg;
 569         struct fc_rport_priv *new_rdata;
 570         struct fc_lport *lport;
 571         struct fc_disc *disc;
 572         struct fc_ct_hdr *cp;
 573         struct fc_ns_gid_pn *pn;
 574         u64 port_name;
 575
 576         lport = rdata->local_port;
 577         disc = &lport->disc;
 578
 579         if (PTR_ERR(fp) == -FC_EX_CLOSED)
 580                 goto out;
 581         if (IS_ERR(fp)) {
 582                 mutex_lock(&disc->disc_mutex);
 583                 fc_disc_restart(disc);
 584                 mutex_unlock(&disc->disc_mutex);
 585                 goto out;
 586         }
 587
 588         cp = fc_frame_payload_get(fp, sizeof(*cp));
 589         if (!cp)
 590                 goto redisc;
 591         if (ntohs(cp->ct_cmd) == FC_FS_ACC) {
 592                 if (fr_len(fp) < sizeof(struct fc_frame_header) +
 593                     sizeof(*cp) + sizeof(*pn))
 594                         goto redisc;
 595                 pn = (struct fc_ns_gid_pn *)(cp + 1);
 596                 port_name = get_unaligned_be64(&pn->fn_wwpn);
 597                 mutex_lock(&rdata->rp_mutex);
 598                 if (rdata->ids.port_name == -1)
 599                         rdata->ids.port_name = port_name;
 600                 else if (rdata->ids.port_name != port_name) {
 601                         FC_DISC_DBG(disc, "GPN_ID accepted.  WWPN changed. "
 602                                     "Port-id %6.6x wwpn %16.16llx\n",
 603                                     rdata->ids.port_id, port_name);
 604                         mutex_unlock(&rdata->rp_mutex);
 605                         fc_rport_logoff(rdata);
 606                         mutex_lock(&lport->disc.disc_mutex);
 607                         new_rdata = fc_rport_create(lport, rdata->ids.port_id);
 608                         mutex_unlock(&lport->disc.disc_mutex);
 609                         if (new_rdata) {
 610                                 new_rdata->disc_id = disc->disc_id;
 611                                 fc_rport_login(new_rdata);
 612                         }
 613                         goto free_fp;
 614                 }
 615                 rdata->disc_id = disc->disc_id;
 616                 mutex_unlock(&rdata->rp_mutex);
 617                 fc_rport_login(rdata);
 618         } else if (ntohs(cp->ct_cmd) == FC_FS_RJT) {
 619                 FC_DISC_DBG(disc, "GPN_ID rejected reason %x exp %x\n",
 620                             cp->ct_reason, cp->ct_explan);
 621                 fc_rport_logoff(rdata);
 622         } else {
 623                 FC_DISC_DBG(disc, "GPN_ID unexpected response code %x\n",
 624                             ntohs(cp->ct_cmd));
 625 redisc:
 626                 mutex_lock(&disc->disc_mutex);
 627                 fc_disc_restart(disc);
 628                 mutex_unlock(&disc->disc_mutex);
 629         }
 630 free_fp:
 631         fc_frame_free(fp);
 632 out:
 633         kref_put(&rdata->kref, fc_rport_destroy);
 634 }
 635
 636 /**
 637  * fc_disc_gpn_id_req() - Send Get Port Names by ID (GPN_ID) request
 638  * @lport: The local port to initiate discovery on
 639  * @rdata: remote port private data
 640  *
 641  * On failure, an error code is returned.
 642  */
 643 static int fc_disc_gpn_id_req(struct fc_lport *lport,
 644                               struct fc_rport_priv *rdata)
 645 {
 646         struct fc_frame *fp;
 647
 648         lockdep_assert_held(&lport->disc.disc_mutex);
 649         fp = fc_frame_alloc(lport, sizeof(struct fc_ct_hdr) +
 650                             sizeof(struct fc_ns_fid));
 651         if (!fp)
 652                 return -ENOMEM;
 653         if (!lport->tt.elsct_send(lport, rdata->ids.port_id, fp, FC_NS_GPN_ID,
 654                                   fc_disc_gpn_id_resp, rdata,
 655                                   3 * lport->r_a_tov))
 656                 return -ENOMEM;
 657         kref_get(&rdata->kref);
 658         return 0;
 659 }
 660
 661 /**
 662  * fc_disc_single() - Discover the directory information for a single target
 663  * @lport: The local port the remote port is associated with
 664  * @dp:    The port to rediscover
 665  */
 666 static int fc_disc_single(struct fc_lport *lport, struct fc_disc_port *dp)
 667 {
 668         struct fc_rport_priv *rdata;
 669
 670         lockdep_assert_held(&lport->disc.disc_mutex);
 671
 672         rdata = fc_rport_create(lport, dp->port_id);
 673         if (!rdata)
 674                 return -ENOMEM;
 675         rdata->disc_id = 0;
 676         return fc_disc_gpn_id_req(lport, rdata);
 677 }
 678
 679 /**
 680  * fc_disc_stop() - Stop discovery for a given lport
 681  * @lport: The local port that discovery should stop on
 682  */
 683 static void fc_disc_stop(struct fc_lport *lport)
 684 {
 685         struct fc_disc *disc = &lport->disc;
 686
 687         if (disc->pending)
 688                 cancel_delayed_work_sync(&disc->disc_work);
 689         mutex_lock(&disc->disc_mutex);
 690         fc_disc_stop_rports(disc);
 691         mutex_unlock(&disc->disc_mutex);
 692 }
 693
 694 /**
 695  * fc_disc_stop_final() - Stop discovery for a given lport
 696  * @lport: The lport that discovery should stop on
 697  *
 698  * This function will block until discovery has been
 699  * completely stopped and all rports have been deleted.
 700  */
 701 static void fc_disc_stop_final(struct fc_lport *lport)
 702 {
 703         fc_disc_stop(lport);
 704         fc_rport_flush_queue();
 705 }
 706
 707 /**
 708  * fc_disc_config() - Configure the discovery layer for a local port
 709  * @lport: The local port that needs the discovery layer to be configured
 710  * @priv: Private data structre for users of the discovery layer
 711  */
 712 void fc_disc_config(struct fc_lport *lport, void *priv)
 713 {
 714         struct fc_disc *disc;
 715
 716         if (!lport->tt.disc_start)
 717                 lport->tt.disc_start = fc_disc_start;
 718
 719         if (!lport->tt.disc_stop)
 720                 lport->tt.disc_stop = fc_disc_stop;
 721
 722         if (!lport->tt.disc_stop_final)
 723                 lport->tt.disc_stop_final = fc_disc_stop_final;
 724
 725         if (!lport->tt.disc_recv_req)
 726                 lport->tt.disc_recv_req = fc_disc_recv_req;
 727
 728         disc = &lport->disc;
 729
 730         disc->priv = priv;
 731 }
 732 EXPORT_SYMBOL(fc_disc_config);
 733
 734 /**
 735  * fc_disc_init() - Initialize the discovery layer for a local port
 736  * @lport: The local port that needs the discovery layer to be initialized
 737  */
 738 void fc_disc_init(struct fc_lport *lport)
 739 {
 740         struct fc_disc *disc = &lport->disc;
 741
 742         INIT_DELAYED_WORK(&disc->disc_work, fc_disc_timeout);
 743         mutex_init(&disc->disc_mutex);
 744         INIT_LIST_HEAD(&disc->rports);
 745 }
 746 EXPORT_SYMBOL(fc_disc_init);