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 #include <linux/in.h>
  30 #include <linux/module.h>
  31 #include <linux/net.h>
  32 #include <linux/ipv6.h>
  33 #include <linux/kthread.h>
  34 #include <linux/errno.h>
  35 #include <linux/kernel.h>
  36 #include <linux/un.h>
  37 #include <linux/uaccess.h>
  38 #include <linux/inet.h>
  39 #include <linux/idr.h>
  40 #include <linux/file.h>
  41 #include <linux/parser.h>
  42 #include <linux/semaphore.h>
  43 #include <net/9p/9p.h>
  44 #include <net/9p/client.h>
  45 #include <net/9p/transport.h>
  46 #include <rdma/ib_verbs.h>
  47 #include <rdma/rdma_cm.h>
  48
  49 #define P9_PORT                 5640
  50 #define P9_RDMA_SQ_DEPTH        32
  51 #define P9_RDMA_RQ_DEPTH        32
  52 #define P9_RDMA_SEND_SGE        4
  53 #define P9_RDMA_RECV_SGE        4
  54 #define P9_RDMA_IRD             0
  55 #define P9_RDMA_ORD             0
  56 #define P9_RDMA_TIMEOUT         30000           /* 30 seconds */
  57 #define P9_RDMA_MAXSIZE         (4*4096)        /* Min SGE is 4, so we can
  58                                                  * safely advertise a maxsize
  59                                                  * of 64k */
  60
  61 #define P9_RDMA_MAX_SGE (P9_RDMA_MAXSIZE >> PAGE_SHIFT)
  62 /**
  63  * struct p9_trans_rdma - RDMA transport instance
  64  *
  65  * @state: tracks the transport state machine for connection setup and tear down
  66  * @cm_id: The RDMA CM ID
  67  * @pd: Protection Domain pointer
  68  * @qp: Queue Pair pointer
  69  * @cq: Completion Queue pointer
  70  * @lkey: The local access only memory region key
  71  * @timeout: Number of uSecs to wait for connection management events
  72  * @sq_depth: The depth of the Send Queue
  73  * @sq_sem: Semaphore for the SQ
  74  * @rq_depth: The depth of the Receive Queue.
  75  * @addr: The remote peer's address
  76  * @req_lock: Protects the active request list
  77  * @send_wait: Wait list when the SQ fills up
  78  * @cm_done: Completion event for connection management tracking
  79  */
  80 struct p9_trans_rdma {
  81         enum {
  82                 P9_RDMA_INIT,
  83                 P9_RDMA_ADDR_RESOLVED,
  84                 P9_RDMA_ROUTE_RESOLVED,
  85                 P9_RDMA_CONNECTED,
  86                 P9_RDMA_FLUSHING,
  87                 P9_RDMA_CLOSING,
  88                 P9_RDMA_CLOSED,
  89         } state;
  90         struct rdma_cm_id *cm_id;
  91         struct ib_pd *pd;
  92         struct ib_qp *qp;
  93         struct ib_cq *cq;
  94         struct ib_mr *dma_mr;
  95         u32 lkey;
  96         long timeout;
  97         int sq_depth;
  98         struct semaphore sq_sem;
  99         int rq_depth;
 100         atomic_t rq_count;
 101         struct sockaddr_in addr;
 102         spinlock_t req_lock;
 103
 104         struct completion cm_done;
 105 };
 106
 107 /**
 108  * p9_rdma_context - Keeps track of in-process WR
 109  *
 110  * @wc_op: The original WR op for when the CQE completes in error.
 111  * @busa: Bus address to unmap when the WR completes
 112  * @req: Keeps track of requests (send)
 113  * @rc: Keepts track of replies (receive)
 114  */
 115 struct p9_rdma_req;
 116 struct p9_rdma_context {
 117         enum ib_wc_opcode wc_op;
 118         dma_addr_t busa;
 119         union {
 120                 struct p9_req_t *req;
 121                 struct p9_fcall *rc;
 122         };
 123 };
 124
 125 /**
 126  * p9_rdma_opts - Collection of mount options
 127  * @port: port of connection
 128  * @sq_depth: The requested depth of the SQ. This really doesn't need
 129  * to be any deeper than the number of threads used in the client
 130  * @rq_depth: The depth of the RQ. Should be greater than or equal to SQ depth
 131  * @timeout: Time to wait in msecs for CM events
 132  */
 133 struct p9_rdma_opts {
 134         short port;
 135         int sq_depth;
 136         int rq_depth;
 137         long timeout;
 138 };
 139
 140 /*
 141  * Option Parsing (code inspired by NFS code)
 142  */
 143 enum {
 144         /* Options that take integer arguments */
 145         Opt_port, Opt_rq_depth, Opt_sq_depth, Opt_timeout, Opt_err,
 146 };
 147
 148 static match_table_t tokens = {
 149         {Opt_port, "port=%u"},
 150         {Opt_sq_depth, "sq=%u"},
 151         {Opt_rq_depth, "rq=%u"},
 152         {Opt_timeout, "timeout=%u"},
 153         {Opt_err, NULL},
 154 };
 155
 156 /**
 157  * parse_options - parse mount options into session structure
 158  * @options: options string passed from mount
 159  * @opts: transport-specific structure to parse options into
 160  *
 161  * Returns 0 upon success, -ERRNO upon failure
 162  */
 163 static int parse_opts(char *params, struct p9_rdma_opts *opts)
 164 {
 165         char *p;
 166         substring_t args[MAX_OPT_ARGS];
 167         int option;
 168         char *options;
 169         int ret;
 170
 171         opts->port = P9_PORT;
 172         opts->sq_depth = P9_RDMA_SQ_DEPTH;
 173         opts->rq_depth = P9_RDMA_RQ_DEPTH;
 174         opts->timeout = P9_RDMA_TIMEOUT;
 175
 176         if (!params)
 177                 return 0;
 178
 179         options = kstrdup(params, GFP_KERNEL);
 180         if (!options) {
 181                 P9_DPRINTK(P9_DEBUG_ERROR,
 182                            "failed to allocate copy of option string\n");
 183                 return -ENOMEM;
 184         }
 185
 186         while ((p = strsep(&options, ",")) != NULL) {
 187                 int token;
 188                 int r;
 189                 if (!*p)
 190                         continue;
 191                 token = match_token(p, tokens, args);
 192                 r = match_int(&args[0], &option);
 193                 if (r < 0) {
 194                         P9_DPRINTK(P9_DEBUG_ERROR,
 195                                    "integer field, but no integer?\n");
 196                         ret = r;
 197                         continue;
 198                 }
 199                 switch (token) {
 200                 case Opt_port:
 201                         opts->port = option;
 202                         break;
 203                 case Opt_sq_depth:
 204                         opts->sq_depth = option;
 205                         break;
 206                 case Opt_rq_depth:
 207                         opts->rq_depth = option;
 208                         break;
 209                 case Opt_timeout:
 210                         opts->timeout = option;
 211                         break;
 212                 default:
 213                         continue;
 214                 }
 215         }
 216         /* RQ must be at least as large as the SQ */
 217         opts->rq_depth = max(opts->rq_depth, opts->sq_depth);
 218         kfree(options);
 219         return 0;
 220 }
 221
 222 static int
 223 p9_cm_event_handler(struct rdma_cm_id *id, struct rdma_cm_event *event)
 224 {
 225         struct p9_client *c = id->context;
 226         struct p9_trans_rdma *rdma = c->trans;
 227         switch (event->event) {
 228         case RDMA_CM_EVENT_ADDR_RESOLVED:
 229                 BUG_ON(rdma->state != P9_RDMA_INIT);
 230                 rdma->state = P9_RDMA_ADDR_RESOLVED;
 231                 break;
 232
 233         case RDMA_CM_EVENT_ROUTE_RESOLVED:
 234                 BUG_ON(rdma->state != P9_RDMA_ADDR_RESOLVED);
 235                 rdma->state = P9_RDMA_ROUTE_RESOLVED;
 236                 break;
 237
 238         case RDMA_CM_EVENT_ESTABLISHED:
 239                 BUG_ON(rdma->state != P9_RDMA_ROUTE_RESOLVED);
 240                 rdma->state = P9_RDMA_CONNECTED;
 241                 break;
 242
 243         case RDMA_CM_EVENT_DISCONNECTED:
 244                 if (rdma)
 245                         rdma->state = P9_RDMA_CLOSED;
 246                 if (c)
 247                         c->status = Disconnected;
 248                 break;
 249
 250         case RDMA_CM_EVENT_TIMEWAIT_EXIT:
 251                 break;
 252
 253         case RDMA_CM_EVENT_ADDR_CHANGE:
 254         case RDMA_CM_EVENT_ROUTE_ERROR:
 255         case RDMA_CM_EVENT_DEVICE_REMOVAL:
 256         case RDMA_CM_EVENT_MULTICAST_JOIN:
 257         case RDMA_CM_EVENT_MULTICAST_ERROR:
 258         case RDMA_CM_EVENT_REJECTED:
 259         case RDMA_CM_EVENT_CONNECT_REQUEST:
 260         case RDMA_CM_EVENT_CONNECT_RESPONSE:
 261         case RDMA_CM_EVENT_CONNECT_ERROR:
 262         case RDMA_CM_EVENT_ADDR_ERROR:
 263         case RDMA_CM_EVENT_UNREACHABLE:
 264                 c->status = Disconnected;
 265                 rdma_disconnect(rdma->cm_id);
 266                 break;
 267         default:
 268                 BUG();
 269         }
 270         complete(&rdma->cm_done);
 271         return 0;
 272 }
 273
 274 static void
 275 handle_recv(struct p9_client *client, struct p9_trans_rdma *rdma,
 276             struct p9_rdma_context *c, enum ib_wc_status status, u32 byte_len)
 277 {
 278         struct p9_req_t *req;
 279         int err = 0;
 280         int16_t tag;
 281
 282         req = NULL;
 283         ib_dma_unmap_single(rdma->cm_id->device, c->busa, client->msize,
 284                                                          DMA_FROM_DEVICE);
 285
 286         if (status != IB_WC_SUCCESS)
 287                 goto err_out;
 288
 289         err = p9_parse_header(c->rc, NULL, NULL, &tag, 1);
 290         if (err)
 291                 goto err_out;
 292
 293         req = p9_tag_lookup(client, tag);
 294         if (!req)
 295                 goto err_out;
 296
 297         req->rc = c->rc;
 298         req->status = REQ_STATUS_RCVD;
 299         p9_client_cb(client, req);
 300
 301         return;
 302
 303  err_out:
 304         P9_DPRINTK(P9_DEBUG_ERROR, "req %p err %d status %d\n",
 305                    req, err, status);
 306         rdma->state = P9_RDMA_FLUSHING;
 307         client->status = Disconnected;
 308         return;
 309 }
 310
 311 static void
 312 handle_send(struct p9_client *client, struct p9_trans_rdma *rdma,
 313             struct p9_rdma_context *c, enum ib_wc_status status, u32 byte_len)
 314 {
 315         ib_dma_unmap_single(rdma->cm_id->device,
 316                             c->busa, c->req->tc->size,
 317                             DMA_TO_DEVICE);
 318 }
 319
 320 static void qp_event_handler(struct ib_event *event, void *context)
 321 {
 322         P9_DPRINTK(P9_DEBUG_ERROR, "QP event %d context %p\n", event->event,
 323                                                                 context);
 324 }
 325
 326 static void cq_comp_handler(struct ib_cq *cq, void *cq_context)
 327 {
 328         struct p9_client *client = cq_context;
 329         struct p9_trans_rdma *rdma = client->trans;
 330         int ret;
 331         struct ib_wc wc;
 332
 333         ib_req_notify_cq(rdma->cq, IB_CQ_NEXT_COMP);
 334         while ((ret = ib_poll_cq(cq, 1, &wc)) > 0) {
 335                 struct p9_rdma_context *c = (void *) (unsigned long) wc.wr_id;
 336
 337                 switch (c->wc_op) {
 338                 case IB_WC_RECV:
 339                         atomic_dec(&rdma->rq_count);
 340                         handle_recv(client, rdma, c, wc.status, wc.byte_len);
 341                         break;
 342
 343                 case IB_WC_SEND:
 344                         handle_send(client, rdma, c, wc.status, wc.byte_len);
 345                         up(&rdma->sq_sem);
 346                         break;
 347
 348                 default:
 349                         printk(KERN_ERR "9prdma: unexpected completion type, "
 350                                "c->wc_op=%d, wc.opcode=%d, status=%d\n",
 351                                c->wc_op, wc.opcode, wc.status);
 352                         break;
 353                 }
 354                 kfree(c);
 355         }
 356 }
 357
 358 static void cq_event_handler(struct ib_event *e, void *v)
 359 {
 360         P9_DPRINTK(P9_DEBUG_ERROR, "CQ event %d context %p\n", e->event, v);
 361 }
 362
 363 static void rdma_destroy_trans(struct p9_trans_rdma *rdma)
 364 {
 365         if (!rdma)
 366                 return;
 367
 368         if (rdma->dma_mr && !IS_ERR(rdma->dma_mr))
 369                 ib_dereg_mr(rdma->dma_mr);
 370
 371         if (rdma->qp && !IS_ERR(rdma->qp))
 372                 ib_destroy_qp(rdma->qp);
 373
 374         if (rdma->pd && !IS_ERR(rdma->pd))
 375                 ib_dealloc_pd(rdma->pd);
 376
 377         if (rdma->cq && !IS_ERR(rdma->cq))
 378                 ib_destroy_cq(rdma->cq);
 379
 380         if (rdma->cm_id && !IS_ERR(rdma->cm_id))
 381                 rdma_destroy_id(rdma->cm_id);
 382
 383         kfree(rdma);
 384 }
 385
 386 static int
 387 post_recv(struct p9_client *client, struct p9_rdma_context *c)
 388 {
 389         struct p9_trans_rdma *rdma = client->trans;
 390         struct ib_recv_wr wr, *bad_wr;
 391         struct ib_sge sge;
 392
 393         c->busa = ib_dma_map_single(rdma->cm_id->device,
 394                                     c->rc->sdata, client->msize,
 395                                     DMA_FROM_DEVICE);
 396         if (ib_dma_mapping_error(rdma->cm_id->device, c->busa))
 397                 goto error;
 398
 399         sge.addr = c->busa;
 400         sge.length = client->msize;
 401         sge.lkey = rdma->lkey;
 402
 403         wr.next = NULL;
 404         c->wc_op = IB_WC_RECV;
 405         wr.wr_id = (unsigned long) c;
 406         wr.sg_list = &sge;
 407         wr.num_sge = 1;
 408         return ib_post_recv(rdma->qp, &wr, &bad_wr);
 409
 410  error:
 411         P9_DPRINTK(P9_DEBUG_ERROR, "EIO\n");
 412         return -EIO;
 413 }
 414
 415 static int rdma_request(struct p9_client *client, struct p9_req_t *req)
 416 {
 417         struct p9_trans_rdma *rdma = client->trans;
 418         struct ib_send_wr wr, *bad_wr;
 419         struct ib_sge sge;
 420         int err = 0;
 421         unsigned long flags;
 422         struct p9_rdma_context *c = NULL;
 423         struct p9_rdma_context *rpl_context = NULL;
 424
 425         /* Allocate an fcall for the reply */
 426         rpl_context = kmalloc(sizeof *rpl_context, GFP_KERNEL);
 427         if (!rpl_context)
 428                 goto err_close;
 429
 430         /*
 431          * If the request has a buffer, steal it, otherwise
 432          * allocate a new one.  Typically, requests should already
 433          * have receive buffers allocated and just swap them around
 434          */
 435         if (!req->rc) {
 436                 req->rc = kmalloc(sizeof(struct p9_fcall)+client->msize,
 437                                                                 GFP_KERNEL);
 438                 if (req->rc) {
 439                         req->rc->sdata = (char *) req->rc +
 440                                                 sizeof(struct p9_fcall);
 441                         req->rc->capacity = client->msize;
 442                 }
 443         }
 444         rpl_context->rc = req->rc;
 445         if (!rpl_context->rc) {
 446                 kfree(rpl_context);
 447                 goto err_close;
 448         }
 449
 450         /*
 451          * Post a receive buffer for this request. We need to ensure
 452          * there is a reply buffer available for every outstanding
 453          * request. A flushed request can result in no reply for an
 454          * outstanding request, so we must keep a count to avoid
 455          * overflowing the RQ.
 456          */
 457         if (atomic_inc_return(&rdma->rq_count) <= rdma->rq_depth) {
 458                 err = post_recv(client, rpl_context);
 459                 if (err) {
 460                         kfree(rpl_context->rc);
 461                         kfree(rpl_context);
 462                         goto err_close;
 463                 }
 464         } else
 465                 atomic_dec(&rdma->rq_count);
 466
 467         /* remove posted receive buffer from request structure */
 468         req->rc = NULL;
 469
 470         /* Post the request */
 471         c = kmalloc(sizeof *c, GFP_KERNEL);
 472         if (!c)
 473                 goto err_close;
 474         c->req = req;
 475
 476         c->busa = ib_dma_map_single(rdma->cm_id->device,
 477                                     c->req->tc->sdata, c->req->tc->size,
 478                                     DMA_TO_DEVICE);
 479         if (ib_dma_mapping_error(rdma->cm_id->device, c->busa))
 480                 goto error;
 481
 482         sge.addr = c->busa;
 483         sge.length = c->req->tc->size;
 484         sge.lkey = rdma->lkey;
 485
 486         wr.next = NULL;
 487         c->wc_op = IB_WC_SEND;
 488         wr.wr_id = (unsigned long) c;
 489         wr.opcode = IB_WR_SEND;
 490         wr.send_flags = IB_SEND_SIGNALED;
 491         wr.sg_list = &sge;
 492         wr.num_sge = 1;
 493
 494         if (down_interruptible(&rdma->sq_sem))
 495                 goto error;
 496
 497         return ib_post_send(rdma->qp, &wr, &bad_wr);
 498
 499  error:
 500         P9_DPRINTK(P9_DEBUG_ERROR, "EIO\n");
 501         return -EIO;
 502
 503  err_close:
 504         spin_lock_irqsave(&rdma->req_lock, flags);
 505         if (rdma->state < P9_RDMA_CLOSING) {
 506                 rdma->state = P9_RDMA_CLOSING;
 507                 spin_unlock_irqrestore(&rdma->req_lock, flags);
 508                 rdma_disconnect(rdma->cm_id);
 509         } else
 510                 spin_unlock_irqrestore(&rdma->req_lock, flags);
 511         return err;
 512 }
 513
 514 static void rdma_close(struct p9_client *client)
 515 {
 516         struct p9_trans_rdma *rdma;
 517
 518         if (!client)
 519                 return;
 520
 521         rdma = client->trans;
 522         if (!rdma)
 523                 return;
 524
 525         client->status = Disconnected;
 526         rdma_disconnect(rdma->cm_id);
 527         rdma_destroy_trans(rdma);
 528 }
 529
 530 /**
 531  * alloc_rdma - Allocate and initialize the rdma transport structure
 532  * @opts: Mount options structure
 533  */
 534 static struct p9_trans_rdma *alloc_rdma(struct p9_rdma_opts *opts)
 535 {
 536         struct p9_trans_rdma *rdma;
 537
 538         rdma = kzalloc(sizeof(struct p9_trans_rdma), GFP_KERNEL);
 539         if (!rdma)
 540                 return NULL;
 541
 542         rdma->sq_depth = opts->sq_depth;
 543         rdma->rq_depth = opts->rq_depth;
 544         rdma->timeout = opts->timeout;
 545         spin_lock_init(&rdma->req_lock);
 546         init_completion(&rdma->cm_done);
 547         sema_init(&rdma->sq_sem, rdma->sq_depth);
 548         atomic_set(&rdma->rq_count, 0);
 549
 550         return rdma;
 551 }
 552
 553 /* its not clear to me we can do anything after send has been posted */
 554 static int rdma_cancel(struct p9_client *client, struct p9_req_t *req)
 555 {
 556         return 1;
 557 }
 558
 559 /**
 560  * trans_create_rdma - Transport method for creating atransport instance
 561  * @client: client instance
 562  * @addr: IP address string
 563  * @args: Mount options string
 564  */
 565 static int
 566 rdma_create_trans(struct p9_client *client, const char *addr, char *args)
 567 {
 568         int err;
 569         struct p9_rdma_opts opts;
 570         struct p9_trans_rdma *rdma;
 571         struct rdma_conn_param conn_param;
 572         struct ib_qp_init_attr qp_attr;
 573         struct ib_device_attr devattr;
 574
 575         /* Parse the transport specific mount options */
 576         err = parse_opts(args, &opts);
 577         if (err < 0)
 578                 return err;
 579
 580         /* Create and initialize the RDMA transport structure */
 581         rdma = alloc_rdma(&opts);
 582         if (!rdma)
 583                 return -ENOMEM;
 584
 585         /* Create the RDMA CM ID */
 586         rdma->cm_id = rdma_create_id(p9_cm_event_handler, client, RDMA_PS_TCP);
 587         if (IS_ERR(rdma->cm_id))
 588                 goto error;
 589
 590         /* Associate the client with the transport */
 591         client->trans = rdma;
 592
 593         /* Resolve the server's address */
 594         rdma->addr.sin_family = AF_INET;
 595         rdma->addr.sin_addr.s_addr = in_aton(addr);
 596         rdma->addr.sin_port = htons(opts.port);
 597         err = rdma_resolve_addr(rdma->cm_id, NULL,
 598                                 (struct sockaddr *)&rdma->addr,
 599                                 rdma->timeout);
 600         if (err)
 601                 goto error;
 602         err = wait_for_completion_interruptible(&rdma->cm_done);
 603         if (err || (rdma->state != P9_RDMA_ADDR_RESOLVED))
 604                 goto error;
 605
 606         /* Resolve the route to the server */
 607         err = rdma_resolve_route(rdma->cm_id, rdma->timeout);
 608         if (err)
 609                 goto error;
 610         err = wait_for_completion_interruptible(&rdma->cm_done);
 611         if (err || (rdma->state != P9_RDMA_ROUTE_RESOLVED))
 612                 goto error;
 613
 614         /* Query the device attributes */
 615         err = ib_query_device(rdma->cm_id->device, &devattr);
 616         if (err)
 617                 goto error;
 618
 619         /* Create the Completion Queue */
 620         rdma->cq = ib_create_cq(rdma->cm_id->device, cq_comp_handler,
 621                                 cq_event_handler, client,
 622                                 opts.sq_depth + opts.rq_depth + 1, 0);
 623         if (IS_ERR(rdma->cq))
 624                 goto error;
 625         ib_req_notify_cq(rdma->cq, IB_CQ_NEXT_COMP);
 626
 627         /* Create the Protection Domain */
 628         rdma->pd = ib_alloc_pd(rdma->cm_id->device);
 629         if (IS_ERR(rdma->pd))
 630                 goto error;
 631
 632         /* Cache the DMA lkey in the transport */
 633         rdma->dma_mr = NULL;
 634         if (devattr.device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY)
 635                 rdma->lkey = rdma->cm_id->device->local_dma_lkey;
 636         else {
 637                 rdma->dma_mr = ib_get_dma_mr(rdma->pd, IB_ACCESS_LOCAL_WRITE);
 638                 if (IS_ERR(rdma->dma_mr))
 639                         goto error;
 640                 rdma->lkey = rdma->dma_mr->lkey;
 641         }
 642
 643         /* Create the Queue Pair */
 644         memset(&qp_attr, 0, sizeof qp_attr);
 645         qp_attr.event_handler = qp_event_handler;
 646         qp_attr.qp_context = client;
 647         qp_attr.cap.max_send_wr = opts.sq_depth;
 648         qp_attr.cap.max_recv_wr = opts.rq_depth;
 649         qp_attr.cap.max_send_sge = P9_RDMA_SEND_SGE;
 650         qp_attr.cap.max_recv_sge = P9_RDMA_RECV_SGE;
 651         qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
 652         qp_attr.qp_type = IB_QPT_RC;
 653         qp_attr.send_cq = rdma->cq;
 654         qp_attr.recv_cq = rdma->cq;
 655         err = rdma_create_qp(rdma->cm_id, rdma->pd, &qp_attr);
 656         if (err)
 657                 goto error;
 658         rdma->qp = rdma->cm_id->qp;
 659
 660         /* Request a connection */
 661         memset(&conn_param, 0, sizeof(conn_param));
 662         conn_param.private_data = NULL;
 663         conn_param.private_data_len = 0;
 664         conn_param.responder_resources = P9_RDMA_IRD;
 665         conn_param.initiator_depth = P9_RDMA_ORD;
 666         err = rdma_connect(rdma->cm_id, &conn_param);
 667         if (err)
 668                 goto error;
 669         err = wait_for_completion_interruptible(&rdma->cm_done);
 670         if (err || (rdma->state != P9_RDMA_CONNECTED))
 671                 goto error;
 672
 673         client->status = Connected;
 674
 675         return 0;
 676
 677 error:
 678         rdma_destroy_trans(rdma);
 679         return -ENOTCONN;
 680 }
 681
 682 static struct p9_trans_module p9_rdma_trans = {
 683         .name = "rdma",
 684         .maxsize = P9_RDMA_MAXSIZE,
 685         .def = 0,
 686         .owner = THIS_MODULE,
 687         .create = rdma_create_trans,
 688         .close = rdma_close,
 689         .request = rdma_request,
 690         .cancel = rdma_cancel,
 691 };
 692
 693 /**
 694  * p9_trans_rdma_init - Register the 9P RDMA transport driver
 695  */
 696 static int __init p9_trans_rdma_init(void)
 697 {
 698         v9fs_register_trans(&p9_rdma_trans);
 699         return 0;
 700 }
 701
 702 static void __exit p9_trans_rdma_exit(void)
 703 {
 704         v9fs_unregister_trans(&p9_rdma_trans);
 705 }
 706
 707 module_init(p9_trans_rdma_init);
 708 module_exit(p9_trans_rdma_exit);
 709
 710 MODULE_AUTHOR("Tom Tucker <tom@opengridcomputing.com>");
 711 MODULE_DESCRIPTION("RDMA Transport for 9P");
 712 MODULE_LICENSE("Dual BSD/GPL");