net/9p/trans_rdma.c

   1 /*
   2  * linux/fs/9p/trans_rdma.c
   3  *
   4  * RDMA transport layer based on the trans_fd.c implementation.
   5  *
   6  *  Copyright (C) 2008 by Tom Tucker <tom@opengridcomputing.com>
   7  *  Copyright (C) 2006 by Russ Cox <rsc@swtch.com>
   8  *  Copyright (C) 2004-2005 by Latchesar Ionkov <lucho@ionkov.net>
   9  *  Copyright (C) 2004-2008 by Eric Van Hensbergen <ericvh@gmail.com>
  10  *  Copyright (C) 1997-2002 by Ron Minnich <rminnich@sarnoff.com>
  11  *
  12  *  This program is free software; you can redistribute it and/or modify
  13  *  it under the terms of the GNU General Public License version 2
  14  *  as published by the Free Software Foundation.
  15  *
  16  *  This program is distributed in the hope that it will be useful,
  17  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  *  GNU General Public License for more details.
  20  *
  21  *  You should have received a copy of the GNU General Public License
  22  *  along with this program; if not, write to:
  23  *  Free Software Foundation
  24  *  51 Franklin Street, Fifth Floor
  25  *  Boston, MA  02111-1301  USA
  26  *
  27  */
  28
  29 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  30
  31 #include <linux/in.h>
  32 #include <linux/module.h>
  33 #include <linux/net.h>
  34 #include <linux/ipv6.h>
  35 #include <linux/kthread.h>
  36 #include <linux/errno.h>
  37 #include <linux/kernel.h>
  38 #include <linux/un.h>
  39 #include <linux/uaccess.h>
  40 #include <linux/inet.h>
  41 #include <linux/idr.h>
  42 #include <linux/file.h>
  43 #include <linux/parser.h>
  44 #include <linux/semaphore.h>
  45 #include <linux/slab.h>
  46 #include <linux/seq_file.h>
  47 #include <net/9p/9p.h>
  48 #include <net/9p/client.h>
  49 #include <net/9p/transport.h>
  50 #include <rdma/ib_verbs.h>
  51 #include <rdma/rdma_cm.h>
  52
  53 #define P9_PORT                 5640
  54 #define P9_RDMA_SQ_DEPTH        32
  55 #define P9_RDMA_RQ_DEPTH        32
  56 #define P9_RDMA_SEND_SGE        4
  57 #define P9_RDMA_RECV_SGE        4
  58 #define P9_RDMA_IRD             0
  59 #define P9_RDMA_ORD             0
  60 #define P9_RDMA_TIMEOUT         30000           /* 30 seconds */
  61 #define P9_RDMA_MAXSIZE         (1024*1024)     /* 1MB */
  62
  63 /**
  64  * struct p9_trans_rdma - RDMA transport instance
  65  *
  66  * @state: tracks the transport state machine for connection setup and tear down
  67  * @cm_id: The RDMA CM ID
  68  * @pd: Protection Domain pointer
  69  * @qp: Queue Pair pointer
  70  * @cq: Completion Queue pointer
  71  * @timeout: Number of uSecs to wait for connection management events
  72  * @privport: Whether a privileged port may be used
  73  * @port: The port to use
  74  * @sq_depth: The depth of the Send Queue
  75  * @sq_sem: Semaphore for the SQ
  76  * @rq_depth: The depth of the Receive Queue.
  77  * @rq_sem: Semaphore for the RQ
  78  * @excess_rc : Amount of posted Receive Contexts without a pending request.
  79  *              See rdma_request()
  80  * @addr: The remote peer's address
  81  * @req_lock: Protects the active request list
  82  * @cm_done: Completion event for connection management tracking
  83  */
  84 struct p9_trans_rdma {
  85         enum {
  86                 P9_RDMA_INIT,
  87                 P9_RDMA_ADDR_RESOLVED,
  88                 P9_RDMA_ROUTE_RESOLVED,
  89                 P9_RDMA_CONNECTED,
  90                 P9_RDMA_FLUSHING,
  91                 P9_RDMA_CLOSING,
  92                 P9_RDMA_CLOSED,
  93         } state;
  94         struct rdma_cm_id *cm_id;
  95         struct ib_pd *pd;
  96         struct ib_qp *qp;
  97         struct ib_cq *cq;
  98         long timeout;
  99         bool privport;
 100         u16 port;
 101         int sq_depth;
 102         struct semaphore sq_sem;
 103         int rq_depth;
 104         struct semaphore rq_sem;
 105         atomic_t excess_rc;
 106         struct sockaddr_in addr;
 107         spinlock_t req_lock;
 108
 109         struct completion cm_done;
 110 };
 111
 112 /**
 113  * p9_rdma_context - Keeps track of in-process WR
 114  *
 115  * @busa: Bus address to unmap when the WR completes
 116  * @req: Keeps track of requests (send)
 117  * @rc: Keepts track of replies (receive)
 118  */
 119 struct p9_rdma_req;
 120 struct p9_rdma_context {
 121         struct ib_cqe cqe;
 122         dma_addr_t busa;
 123         union {
 124                 struct p9_req_t *req;
 125                 struct p9_fcall *rc;
 126         };
 127 };
 128
 129 /**
 130  * p9_rdma_opts - Collection of mount options
 131  * @port: port of connection
 132  * @sq_depth: The requested depth of the SQ. This really doesn't need
 133  * to be any deeper than the number of threads used in the client
 134  * @rq_depth: The depth of the RQ. Should be greater than or equal to SQ depth
 135  * @timeout: Time to wait in msecs for CM events
 136  */
 137 struct p9_rdma_opts {
 138         short port;
 139         bool privport;
 140         int sq_depth;
 141         int rq_depth;
 142         long timeout;
 143 };
 144
 145 /*
 146  * Option Parsing (code inspired by NFS code)
 147  */
 148 enum {
 149         /* Options that take integer arguments */
 150         Opt_port, Opt_rq_depth, Opt_sq_depth, Opt_timeout,
 151         /* Options that take no argument */
 152         Opt_privport,
 153         Opt_err,
 154 };
 155
 156 static match_table_t tokens = {
 157         {Opt_port, "port=%u"},
 158         {Opt_sq_depth, "sq=%u"},
 159         {Opt_rq_depth, "rq=%u"},
 160         {Opt_timeout, "timeout=%u"},
 161         {Opt_privport, "privport"},
 162         {Opt_err, NULL},
 163 };
 164
 165 static int p9_rdma_show_options(struct seq_file *m, struct p9_client *clnt)
 166 {
 167         struct p9_trans_rdma *rdma = clnt->trans;
 168
 169         if (rdma->port != P9_PORT)
 170                 seq_printf(m, ",port=%u", rdma->port);
 171         if (rdma->sq_depth != P9_RDMA_SQ_DEPTH)
 172                 seq_printf(m, ",sq=%u", rdma->sq_depth);
 173         if (rdma->rq_depth != P9_RDMA_RQ_DEPTH)
 174                 seq_printf(m, ",rq=%u", rdma->rq_depth);
 175         if (rdma->timeout != P9_RDMA_TIMEOUT)
 176                 seq_printf(m, ",timeout=%lu", rdma->timeout);
 177         if (rdma->privport)
 178                 seq_puts(m, ",privport");
 179         return 0;
 180 }
 181
 182 /**
 183  * parse_opts - parse mount options into rdma options structure
 184  * @params: options string passed from mount
 185  * @opts: rdma transport-specific structure to parse options into
 186  *
 187  * Returns 0 upon success, -ERRNO upon failure
 188  */
 189 static int parse_opts(char *params, struct p9_rdma_opts *opts)
 190 {
 191         char *p;
 192         substring_t args[MAX_OPT_ARGS];
 193         int option;
 194         char *options, *tmp_options;
 195
 196         opts->port = P9_PORT;
 197         opts->sq_depth = P9_RDMA_SQ_DEPTH;
 198         opts->rq_depth = P9_RDMA_RQ_DEPTH;
 199         opts->timeout = P9_RDMA_TIMEOUT;
 200         opts->privport = false;
 201
 202         if (!params)
 203                 return 0;
 204
 205         tmp_options = kstrdup(params, GFP_KERNEL);
 206         if (!tmp_options) {
 207                 p9_debug(P9_DEBUG_ERROR,
 208                          "failed to allocate copy of option string\n");
 209                 return -ENOMEM;
 210         }
 211         options = tmp_options;
 212
 213         while ((p = strsep(&options, ",")) != NULL) {
 214                 int token;
 215                 int r;
 216                 if (!*p)
 217                         continue;
 218                 token = match_token(p, tokens, args);
 219                 if ((token != Opt_err) && (token != Opt_privport)) {
 220                         r = match_int(&args[0], &option);
 221                         if (r < 0) {
 222                                 p9_debug(P9_DEBUG_ERROR,
 223                                          "integer field, but no integer?\n");
 224                                 continue;
 225                         }
 226                 }
 227                 switch (token) {
 228                 case Opt_port:
 229                         opts->port = option;
 230                         break;
 231                 case Opt_sq_depth:
 232                         opts->sq_depth = option;
 233                         break;
 234                 case Opt_rq_depth:
 235                         opts->rq_depth = option;
 236                         break;
 237                 case Opt_timeout:
 238                         opts->timeout = option;
 239                         break;
 240                 case Opt_privport:
 241                         opts->privport = true;
 242                         break;
 243                 default:
 244                         continue;
 245                 }
 246         }
 247         /* RQ must be at least as large as the SQ */
 248         opts->rq_depth = max(opts->rq_depth, opts->sq_depth);
 249         kfree(tmp_options);
 250         return 0;
 251 }
 252
 253 static int
 254 p9_cm_event_handler(struct rdma_cm_id *id, struct rdma_cm_event *event)
 255 {
 256         struct p9_client *c = id->context;
 257         struct p9_trans_rdma *rdma = c->trans;
 258         switch (event->event) {
 259         case RDMA_CM_EVENT_ADDR_RESOLVED:
 260                 BUG_ON(rdma->state != P9_RDMA_INIT);
 261                 rdma->state = P9_RDMA_ADDR_RESOLVED;
 262                 break;
 263
 264         case RDMA_CM_EVENT_ROUTE_RESOLVED:
 265                 BUG_ON(rdma->state != P9_RDMA_ADDR_RESOLVED);
 266                 rdma->state = P9_RDMA_ROUTE_RESOLVED;
 267                 break;
 268
 269         case RDMA_CM_EVENT_ESTABLISHED:
 270                 BUG_ON(rdma->state != P9_RDMA_ROUTE_RESOLVED);
 271                 rdma->state = P9_RDMA_CONNECTED;
 272                 break;
 273
 274         case RDMA_CM_EVENT_DISCONNECTED:
 275                 if (rdma)
 276                         rdma->state = P9_RDMA_CLOSED;
 277                 if (c)
 278                         c->status = Disconnected;
 279                 break;
 280
 281         case RDMA_CM_EVENT_TIMEWAIT_EXIT:
 282                 break;
 283
 284         case RDMA_CM_EVENT_ADDR_CHANGE:
 285         case RDMA_CM_EVENT_ROUTE_ERROR:
 286         case RDMA_CM_EVENT_DEVICE_REMOVAL:
 287         case RDMA_CM_EVENT_MULTICAST_JOIN:
 288         case RDMA_CM_EVENT_MULTICAST_ERROR:
 289         case RDMA_CM_EVENT_REJECTED:
 290         case RDMA_CM_EVENT_CONNECT_REQUEST:
 291         case RDMA_CM_EVENT_CONNECT_RESPONSE:
 292         case RDMA_CM_EVENT_CONNECT_ERROR:
 293         case RDMA_CM_EVENT_ADDR_ERROR:
 294         case RDMA_CM_EVENT_UNREACHABLE:
 295                 c->status = Disconnected;
 296                 rdma_disconnect(rdma->cm_id);
 297                 break;
 298         default:
 299                 BUG();
 300         }
 301         complete(&rdma->cm_done);
 302         return 0;
 303 }
 304
 305 static void
 306 recv_done(struct ib_cq *cq, struct ib_wc *wc)
 307 {
 308         struct p9_client *client = cq->cq_context;
 309         struct p9_trans_rdma *rdma = client->trans;
 310         struct p9_rdma_context *c =
 311                 container_of(wc->wr_cqe, struct p9_rdma_context, cqe);
 312         struct p9_req_t *req;
 313         int err = 0;
 314         int16_t tag;
 315
 316         req = NULL;
 317         ib_dma_unmap_single(rdma->cm_id->device, c->busa, client->msize,
 318                                                          DMA_FROM_DEVICE);
 319
 320         if (wc->status != IB_WC_SUCCESS)
 321                 goto err_out;
 322
 323         c->rc->size = wc->byte_len;
 324         err = p9_parse_header(c->rc, NULL, NULL, &tag, 1);
 325         if (err)
 326                 goto err_out;
 327
 328         req = p9_tag_lookup(client, tag);
 329         if (!req)
 330                 goto err_out;
 331
 332         /* Check that we have not yet received a reply for this request.
 333          */
 334         if (unlikely(req->rc)) {
 335                 pr_err("Duplicate reply for request %d", tag);
 336                 goto err_out;
 337         }
 338
 339         req->rc = c->rc;
 340         p9_client_cb(client, req, REQ_STATUS_RCVD);
 341
 342  out:
 343         up(&rdma->rq_sem);
 344         kfree(c);
 345         return;
 346
 347  err_out:
 348         p9_debug(P9_DEBUG_ERROR, "req %p err %d status %d\n",
 349                         req, err, wc->status);
 350         rdma->state = P9_RDMA_FLUSHING;
 351         client->status = Disconnected;
 352         goto out;
 353 }
 354
 355 static void
 356 send_done(struct ib_cq *cq, struct ib_wc *wc)
 357 {
 358         struct p9_client *client = cq->cq_context;
 359         struct p9_trans_rdma *rdma = client->trans;
 360         struct p9_rdma_context *c =
 361                 container_of(wc->wr_cqe, struct p9_rdma_context, cqe);
 362
 363         ib_dma_unmap_single(rdma->cm_id->device,
 364                             c->busa, c->req->tc->size,
 365                             DMA_TO_DEVICE);
 366         up(&rdma->sq_sem);
 367         kfree(c);
 368 }
 369
 370 static void qp_event_handler(struct ib_event *event, void *context)
 371 {
 372         p9_debug(P9_DEBUG_ERROR, "QP event %d context %p\n",
 373                  event->event, context);
 374 }
 375
 376 static void rdma_destroy_trans(struct p9_trans_rdma *rdma)
 377 {
 378         if (!rdma)
 379                 return;
 380
 381         if (rdma->qp && !IS_ERR(rdma->qp))
 382                 ib_destroy_qp(rdma->qp);
 383
 384         if (rdma->pd && !IS_ERR(rdma->pd))
 385                 ib_dealloc_pd(rdma->pd);
 386
 387         if (rdma->cq && !IS_ERR(rdma->cq))
 388                 ib_free_cq(rdma->cq);
 389
 390         if (rdma->cm_id && !IS_ERR(rdma->cm_id))
 391                 rdma_destroy_id(rdma->cm_id);
 392
 393         kfree(rdma);
 394 }
 395
 396 static int
 397 post_recv(struct p9_client *client, struct p9_rdma_context *c)
 398 {
 399         struct p9_trans_rdma *rdma = client->trans;
 400         struct ib_recv_wr wr;
 401         struct ib_sge sge;
 402
 403         c->busa = ib_dma_map_single(rdma->cm_id->device,
 404                                     c->rc->sdata, client->msize,
 405                                     DMA_FROM_DEVICE);
 406         if (ib_dma_mapping_error(rdma->cm_id->device, c->busa))
 407                 goto error;
 408
 409         c->cqe.done = recv_done;
 410
 411         sge.addr = c->busa;
 412         sge.length = client->msize;
 413         sge.lkey = rdma->pd->local_dma_lkey;
 414
 415         wr.next = NULL;
 416         wr.wr_cqe = &c->cqe;
 417         wr.sg_list = &sge;
 418         wr.num_sge = 1;
 419         return ib_post_recv(rdma->qp, &wr, NULL);
 420
 421  error:
 422         p9_debug(P9_DEBUG_ERROR, "EIO\n");
 423         return -EIO;
 424 }
 425
 426 static int rdma_request(struct p9_client *client, struct p9_req_t *req)
 427 {
 428         struct p9_trans_rdma *rdma = client->trans;
 429         struct ib_send_wr wr;
 430         struct ib_sge sge;
 431         int err = 0;
 432         unsigned long flags;
 433         struct p9_rdma_context *c = NULL;
 434         struct p9_rdma_context *rpl_context = NULL;
 435
 436         /* When an error occurs between posting the recv and the send,
 437          * there will be a receive context posted without a pending request.
 438          * Since there is no way to "un-post" it, we remember it and skip
 439          * post_recv() for the next request.
 440          * So here,
 441          * see if we are this `next request' and need to absorb an excess rc.
 442          * If yes, then drop and free our own, and do not recv_post().
 443          **/
 444         if (unlikely(atomic_read(&rdma->excess_rc) > 0)) {
 445                 if ((atomic_sub_return(1, &rdma->excess_rc) >= 0)) {
 446                         /* Got one ! */
 447                         kfree(req->rc);
 448                         req->rc = NULL;
 449                         goto dont_need_post_recv;
 450                 } else {
 451                         /* We raced and lost. */
 452                         atomic_inc(&rdma->excess_rc);
 453                 }
 454         }
 455
 456         /* Allocate an fcall for the reply */
 457         rpl_context = kmalloc(sizeof *rpl_context, GFP_NOFS);
 458         if (!rpl_context) {
 459                 err = -ENOMEM;
 460                 goto recv_error;
 461         }
 462         rpl_context->rc = req->rc;
 463
 464         /*
 465          * Post a receive buffer for this request. We need to ensure
 466          * there is a reply buffer available for every outstanding
 467          * request. A flushed request can result in no reply for an
 468          * outstanding request, so we must keep a count to avoid
 469          * overflowing the RQ.
 470          */
 471         if (down_interruptible(&rdma->rq_sem)) {
 472                 err = -EINTR;
 473                 goto recv_error;
 474         }
 475
 476         err = post_recv(client, rpl_context);
 477         if (err) {
 478                 p9_debug(P9_DEBUG_FCALL, "POST RECV failed\n");
 479                 goto recv_error;
 480         }
 481         /* remove posted receive buffer from request structure */
 482         req->rc = NULL;
 483
 484 dont_need_post_recv:
 485         /* Post the request */
 486         c = kmalloc(sizeof *c, GFP_NOFS);
 487         if (!c) {
 488                 err = -ENOMEM;
 489                 goto send_error;
 490         }
 491         c->req = req;
 492
 493         c->busa = ib_dma_map_single(rdma->cm_id->device,
 494                                     c->req->tc->sdata, c->req->tc->size,
 495                                     DMA_TO_DEVICE);
 496         if (ib_dma_mapping_error(rdma->cm_id->device, c->busa)) {
 497                 err = -EIO;
 498                 goto send_error;
 499         }
 500
 501         c->cqe.done = send_done;
 502
 503         sge.addr = c->busa;
 504         sge.length = c->req->tc->size;
 505         sge.lkey = rdma->pd->local_dma_lkey;
 506
 507         wr.next = NULL;
 508         wr.wr_cqe = &c->cqe;
 509         wr.opcode = IB_WR_SEND;
 510         wr.send_flags = IB_SEND_SIGNALED;
 511         wr.sg_list = &sge;
 512         wr.num_sge = 1;
 513
 514         if (down_interruptible(&rdma->sq_sem)) {
 515                 err = -EINTR;
 516                 goto send_error;
 517         }
 518
 519         /* Mark request as `sent' *before* we actually send it,
 520          * because doing if after could erase the REQ_STATUS_RCVD
 521          * status in case of a very fast reply.
 522          */
 523         req->status = REQ_STATUS_SENT;
 524         err = ib_post_send(rdma->qp, &wr, NULL);
 525         if (err)
 526                 goto send_error;
 527
 528         /* Success */
 529         return 0;
 530
 531  /* Handle errors that happened during or while preparing the send: */
 532  send_error:
 533         req->status = REQ_STATUS_ERROR;
 534         kfree(c);
 535         p9_debug(P9_DEBUG_ERROR, "Error %d in rdma_request()\n", err);
 536
 537         /* Ach.
 538          *  We did recv_post(), but not send. We have one recv_post in excess.
 539          */
 540         atomic_inc(&rdma->excess_rc);
 541         return err;
 542
 543  /* Handle errors that happened during or while preparing post_recv(): */
 544  recv_error:
 545         kfree(rpl_context);
 546         spin_lock_irqsave(&rdma->req_lock, flags);
 547         if (rdma->state < P9_RDMA_CLOSING) {
 548                 rdma->state = P9_RDMA_CLOSING;
 549                 spin_unlock_irqrestore(&rdma->req_lock, flags);
 550                 rdma_disconnect(rdma->cm_id);
 551         } else
 552                 spin_unlock_irqrestore(&rdma->req_lock, flags);
 553         return err;
 554 }
 555
 556 static void rdma_close(struct p9_client *client)
 557 {
 558         struct p9_trans_rdma *rdma;
 559
 560         if (!client)
 561                 return;
 562
 563         rdma = client->trans;
 564         if (!rdma)
 565                 return;
 566
 567         client->status = Disconnected;
 568         rdma_disconnect(rdma->cm_id);
 569         rdma_destroy_trans(rdma);
 570 }
 571
 572 /**
 573  * alloc_rdma - Allocate and initialize the rdma transport structure
 574  * @opts: Mount options structure
 575  */
 576 static struct p9_trans_rdma *alloc_rdma(struct p9_rdma_opts *opts)
 577 {
 578         struct p9_trans_rdma *rdma;
 579
 580         rdma = kzalloc(sizeof(struct p9_trans_rdma), GFP_KERNEL);
 581         if (!rdma)
 582                 return NULL;
 583
 584         rdma->port = opts->port;
 585         rdma->privport = opts->privport;
 586         rdma->sq_depth = opts->sq_depth;
 587         rdma->rq_depth = opts->rq_depth;
 588         rdma->timeout = opts->timeout;
 589         spin_lock_init(&rdma->req_lock);
 590         init_completion(&rdma->cm_done);
 591         sema_init(&rdma->sq_sem, rdma->sq_depth);
 592         sema_init(&rdma->rq_sem, rdma->rq_depth);
 593         atomic_set(&rdma->excess_rc, 0);
 594
 595         return rdma;
 596 }
 597
 598 static int rdma_cancel(struct p9_client *client, struct p9_req_t *req)
 599 {
 600         /* Nothing to do here.
 601          * We will take care of it (if we have to) in rdma_cancelled()
 602          */
 603         return 1;
 604 }
 605
 606 /* A request has been fully flushed without a reply.
 607  * That means we have posted one buffer in excess.
 608  */
 609 static int rdma_cancelled(struct p9_client *client, struct p9_req_t *req)
 610 {
 611         struct p9_trans_rdma *rdma = client->trans;
 612         atomic_inc(&rdma->excess_rc);
 613         return 0;
 614 }
 615
 616 static int p9_rdma_bind_privport(struct p9_trans_rdma *rdma)
 617 {
 618         struct sockaddr_in cl = {
 619                 .sin_family = AF_INET,
 620                 .sin_addr.s_addr = htonl(INADDR_ANY),
 621         };
 622         int port, err = -EINVAL;
 623
 624         for (port = P9_DEF_MAX_RESVPORT; port >= P9_DEF_MIN_RESVPORT; port--) {
 625                 cl.sin_port = htons((ushort)port);
 626                 err = rdma_bind_addr(rdma->cm_id, (struct sockaddr *)&cl);
 627                 if (err != -EADDRINUSE)
 628                         break;
 629         }
 630         return err;
 631 }
 632
 633 /**
 634  * rdma_create_trans - Transport method for creating a transport instance
 635  * @client: client instance
 636  * @addr: IP address string
 637  * @args: Mount options string
 638  */
 639 static int
 640 rdma_create_trans(struct p9_client *client, const char *addr, char *args)
 641 {
 642         int err;
 643         struct p9_rdma_opts opts;
 644         struct p9_trans_rdma *rdma;
 645         struct rdma_conn_param conn_param;
 646         struct ib_qp_init_attr qp_attr;
 647
 648         if (addr == NULL)
 649                 return -EINVAL;
 650
 651         /* Parse the transport specific mount options */
 652         err = parse_opts(args, &opts);
 653         if (err < 0)
 654                 return err;
 655
 656         /* Create and initialize the RDMA transport structure */
 657         rdma = alloc_rdma(&opts);
 658         if (!rdma)
 659                 return -ENOMEM;
 660
 661         /* Create the RDMA CM ID */
 662         rdma->cm_id = rdma_create_id(&init_net, p9_cm_event_handler, client,
 663                                      RDMA_PS_TCP, IB_QPT_RC);
 664         if (IS_ERR(rdma->cm_id))
 665                 goto error;
 666
 667         /* Associate the client with the transport */
 668         client->trans = rdma;
 669
 670         /* Bind to a privileged port if we need to */
 671         if (opts.privport) {
 672                 err = p9_rdma_bind_privport(rdma);
 673                 if (err < 0) {
 674                         pr_err("%s (%d): problem binding to privport: %d\n",
 675                                __func__, task_pid_nr(current), -err);
 676                         goto error;
 677                 }
 678         }
 679
 680         /* Resolve the server's address */
 681         rdma->addr.sin_family = AF_INET;
 682         rdma->addr.sin_addr.s_addr = in_aton(addr);
 683         rdma->addr.sin_port = htons(opts.port);
 684         err = rdma_resolve_addr(rdma->cm_id, NULL,
 685                                 (struct sockaddr *)&rdma->addr,
 686                                 rdma->timeout);
 687         if (err)
 688                 goto error;
 689         err = wait_for_completion_interruptible(&rdma->cm_done);
 690         if (err || (rdma->state != P9_RDMA_ADDR_RESOLVED))
 691                 goto error;
 692
 693         /* Resolve the route to the server */
 694         err = rdma_resolve_route(rdma->cm_id, rdma->timeout);
 695         if (err)
 696                 goto error;
 697         err = wait_for_completion_interruptible(&rdma->cm_done);
 698         if (err || (rdma->state != P9_RDMA_ROUTE_RESOLVED))
 699                 goto error;
 700
 701         /* Create the Completion Queue */
 702         rdma->cq = ib_alloc_cq(rdma->cm_id->device, client,
 703                         opts.sq_depth + opts.rq_depth + 1,
 704                         0, IB_POLL_SOFTIRQ);
 705         if (IS_ERR(rdma->cq))
 706                 goto error;
 707
 708         /* Create the Protection Domain */
 709         rdma->pd = ib_alloc_pd(rdma->cm_id->device, 0);
 710         if (IS_ERR(rdma->pd))
 711                 goto error;
 712
 713         /* Create the Queue Pair */
 714         memset(&qp_attr, 0, sizeof qp_attr);
 715         qp_attr.event_handler = qp_event_handler;
 716         qp_attr.qp_context = client;
 717         qp_attr.cap.max_send_wr = opts.sq_depth;
 718         qp_attr.cap.max_recv_wr = opts.rq_depth;
 719         qp_attr.cap.max_send_sge = P9_RDMA_SEND_SGE;
 720         qp_attr.cap.max_recv_sge = P9_RDMA_RECV_SGE;
 721         qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
 722         qp_attr.qp_type = IB_QPT_RC;
 723         qp_attr.send_cq = rdma->cq;
 724         qp_attr.recv_cq = rdma->cq;
 725         err = rdma_create_qp(rdma->cm_id, rdma->pd, &qp_attr);
 726         if (err)
 727                 goto error;
 728         rdma->qp = rdma->cm_id->qp;
 729
 730         /* Request a connection */
 731         memset(&conn_param, 0, sizeof(conn_param));
 732         conn_param.private_data = NULL;
 733         conn_param.private_data_len = 0;
 734         conn_param.responder_resources = P9_RDMA_IRD;
 735         conn_param.initiator_depth = P9_RDMA_ORD;
 736         err = rdma_connect(rdma->cm_id, &conn_param);
 737         if (err)
 738                 goto error;
 739         err = wait_for_completion_interruptible(&rdma->cm_done);
 740         if (err || (rdma->state != P9_RDMA_CONNECTED))
 741                 goto error;
 742
 743         client->status = Connected;
 744
 745         return 0;
 746
 747 error:
 748         rdma_destroy_trans(rdma);
 749         return -ENOTCONN;
 750 }
 751
 752 static struct p9_trans_module p9_rdma_trans = {
 753         .name = "rdma",
 754         .maxsize = P9_RDMA_MAXSIZE,
 755         .def = 0,
 756         .owner = THIS_MODULE,
 757         .create = rdma_create_trans,
 758         .close = rdma_close,
 759         .request = rdma_request,
 760         .cancel = rdma_cancel,
 761         .cancelled = rdma_cancelled,
 762         .show_options = p9_rdma_show_options,
 763 };
 764
 765 /**
 766  * p9_trans_rdma_init - Register the 9P RDMA transport driver
 767  */
 768 static int __init p9_trans_rdma_init(void)
 769 {
 770         v9fs_register_trans(&p9_rdma_trans);
 771         return 0;
 772 }
 773
 774 static void __exit p9_trans_rdma_exit(void)
 775 {
 776         v9fs_unregister_trans(&p9_rdma_trans);
 777 }
 778
 779 module_init(p9_trans_rdma_init);
 780 module_exit(p9_trans_rdma_exit);
 781
 782 MODULE_AUTHOR("Tom Tucker <tom@opengridcomputing.com>");
 783 MODULE_DESCRIPTION("RDMA Transport for 9P");
 784 MODULE_LICENSE("Dual BSD/GPL");