linux/net/9p/trans_rdma.c
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   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 <net/9p/9p.h>
  47#include <net/9p/client.h>
  48#include <net/9p/transport.h>
  49#include <rdma/ib_verbs.h>
  50#include <rdma/rdma_cm.h>
  51
  52#define P9_PORT                 5640
  53#define P9_RDMA_SQ_DEPTH        32
  54#define P9_RDMA_RQ_DEPTH        32
  55#define P9_RDMA_SEND_SGE        4
  56#define P9_RDMA_RECV_SGE        4
  57#define P9_RDMA_IRD             0
  58#define P9_RDMA_ORD             0
  59#define P9_RDMA_TIMEOUT         30000           /* 30 seconds */
  60#define P9_RDMA_MAXSIZE         (4*4096)        /* Min SGE is 4, so we can
  61                                                 * safely advertise a maxsize
  62                                                 * of 64k */
  63
  64/**
  65 * struct p9_trans_rdma - RDMA transport instance
  66 *
  67 * @state: tracks the transport state machine for connection setup and tear down
  68 * @cm_id: The RDMA CM ID
  69 * @pd: Protection Domain pointer
  70 * @qp: Queue Pair pointer
  71 * @cq: Completion Queue pointer
  72 * @dm_mr: DMA Memory Region pointer
  73 * @lkey: The local access only memory region key
  74 * @timeout: Number of uSecs to wait for connection management events
  75 * @sq_depth: The depth of the Send Queue
  76 * @sq_sem: Semaphore for the SQ
  77 * @rq_depth: The depth of the Receive Queue.
  78 * @rq_count: Count of requests in the Receive Queue.
  79 * @addr: The remote peer's address
  80 * @req_lock: Protects the active request list
  81 * @cm_done: Completion event for connection management tracking
  82 */
  83struct p9_trans_rdma {
  84        enum {
  85                P9_RDMA_INIT,
  86                P9_RDMA_ADDR_RESOLVED,
  87                P9_RDMA_ROUTE_RESOLVED,
  88                P9_RDMA_CONNECTED,
  89                P9_RDMA_FLUSHING,
  90                P9_RDMA_CLOSING,
  91                P9_RDMA_CLOSED,
  92        } state;
  93        struct rdma_cm_id *cm_id;
  94        struct ib_pd *pd;
  95        struct ib_qp *qp;
  96        struct ib_cq *cq;
  97        struct ib_mr *dma_mr;
  98        u32 lkey;
  99        long timeout;
 100        int sq_depth;
 101        struct semaphore sq_sem;
 102        int rq_depth;
 103        atomic_t rq_count;
 104        struct sockaddr_in addr;
 105        spinlock_t req_lock;
 106
 107        struct completion cm_done;
 108};
 109
 110/**
 111 * p9_rdma_context - Keeps track of in-process WR
 112 *
 113 * @wc_op: The original WR op for when the CQE completes in error.
 114 * @busa: Bus address to unmap when the WR completes
 115 * @req: Keeps track of requests (send)
 116 * @rc: Keepts track of replies (receive)
 117 */
 118struct p9_rdma_req;
 119struct p9_rdma_context {
 120        enum ib_wc_opcode wc_op;
 121        dma_addr_t busa;
 122        union {
 123                struct p9_req_t *req;
 124                struct p9_fcall *rc;
 125        };
 126};
 127
 128/**
 129 * p9_rdma_opts - Collection of mount options
 130 * @port: port of connection
 131 * @sq_depth: The requested depth of the SQ. This really doesn't need
 132 * to be any deeper than the number of threads used in the client
 133 * @rq_depth: The depth of the RQ. Should be greater than or equal to SQ depth
 134 * @timeout: Time to wait in msecs for CM events
 135 */
 136struct p9_rdma_opts {
 137        short port;
 138        int sq_depth;
 139        int rq_depth;
 140        long timeout;
 141};
 142
 143/*
 144 * Option Parsing (code inspired by NFS code)
 145 */
 146enum {
 147        /* Options that take integer arguments */
 148        Opt_port, Opt_rq_depth, Opt_sq_depth, Opt_timeout, Opt_err,
 149};
 150
 151static match_table_t tokens = {
 152        {Opt_port, "port=%u"},
 153        {Opt_sq_depth, "sq=%u"},
 154        {Opt_rq_depth, "rq=%u"},
 155        {Opt_timeout, "timeout=%u"},
 156        {Opt_err, NULL},
 157};
 158
 159/**
 160 * parse_opts - parse mount options into rdma options structure
 161 * @params: options string passed from mount
 162 * @opts: rdma transport-specific structure to parse options into
 163 *
 164 * Returns 0 upon success, -ERRNO upon failure
 165 */
 166static int parse_opts(char *params, struct p9_rdma_opts *opts)
 167{
 168        char *p;
 169        substring_t args[MAX_OPT_ARGS];
 170        int option;
 171        char *options, *tmp_options;
 172
 173        opts->port = P9_PORT;
 174        opts->sq_depth = P9_RDMA_SQ_DEPTH;
 175        opts->rq_depth = P9_RDMA_RQ_DEPTH;
 176        opts->timeout = P9_RDMA_TIMEOUT;
 177
 178        if (!params)
 179                return 0;
 180
 181        tmp_options = kstrdup(params, GFP_KERNEL);
 182        if (!tmp_options) {
 183                p9_debug(P9_DEBUG_ERROR,
 184                         "failed to allocate copy of option string\n");
 185                return -ENOMEM;
 186        }
 187        options = tmp_options;
 188
 189        while ((p = strsep(&options, ",")) != NULL) {
 190                int token;
 191                int r;
 192                if (!*p)
 193                        continue;
 194                token = match_token(p, tokens, args);
 195                r = match_int(&args[0], &option);
 196                if (r < 0) {
 197                        p9_debug(P9_DEBUG_ERROR,
 198                                 "integer field, but no integer?\n");
 199                        continue;
 200                }
 201                switch (token) {
 202                case Opt_port:
 203                        opts->port = option;
 204                        break;
 205                case Opt_sq_depth:
 206                        opts->sq_depth = option;
 207                        break;
 208                case Opt_rq_depth:
 209                        opts->rq_depth = option;
 210                        break;
 211                case Opt_timeout:
 212                        opts->timeout = option;
 213                        break;
 214                default:
 215                        continue;
 216                }
 217        }
 218        /* RQ must be at least as large as the SQ */
 219        opts->rq_depth = max(opts->rq_depth, opts->sq_depth);
 220        kfree(tmp_options);
 221        return 0;
 222}
 223
 224static int
 225p9_cm_event_handler(struct rdma_cm_id *id, struct rdma_cm_event *event)
 226{
 227        struct p9_client *c = id->context;
 228        struct p9_trans_rdma *rdma = c->trans;
 229        switch (event->event) {
 230        case RDMA_CM_EVENT_ADDR_RESOLVED:
 231                BUG_ON(rdma->state != P9_RDMA_INIT);
 232                rdma->state = P9_RDMA_ADDR_RESOLVED;
 233                break;
 234
 235        case RDMA_CM_EVENT_ROUTE_RESOLVED:
 236                BUG_ON(rdma->state != P9_RDMA_ADDR_RESOLVED);
 237                rdma->state = P9_RDMA_ROUTE_RESOLVED;
 238                break;
 239
 240        case RDMA_CM_EVENT_ESTABLISHED:
 241                BUG_ON(rdma->state != P9_RDMA_ROUTE_RESOLVED);
 242                rdma->state = P9_RDMA_CONNECTED;
 243                break;
 244
 245        case RDMA_CM_EVENT_DISCONNECTED:
 246                if (rdma)
 247                        rdma->state = P9_RDMA_CLOSED;
 248                if (c)
 249                        c->status = Disconnected;
 250                break;
 251
 252        case RDMA_CM_EVENT_TIMEWAIT_EXIT:
 253                break;
 254
 255        case RDMA_CM_EVENT_ADDR_CHANGE:
 256        case RDMA_CM_EVENT_ROUTE_ERROR:
 257        case RDMA_CM_EVENT_DEVICE_REMOVAL:
 258        case RDMA_CM_EVENT_MULTICAST_JOIN:
 259        case RDMA_CM_EVENT_MULTICAST_ERROR:
 260        case RDMA_CM_EVENT_REJECTED:
 261        case RDMA_CM_EVENT_CONNECT_REQUEST:
 262        case RDMA_CM_EVENT_CONNECT_RESPONSE:
 263        case RDMA_CM_EVENT_CONNECT_ERROR:
 264        case RDMA_CM_EVENT_ADDR_ERROR:
 265        case RDMA_CM_EVENT_UNREACHABLE:
 266                c->status = Disconnected;
 267                rdma_disconnect(rdma->cm_id);
 268                break;
 269        default:
 270                BUG();
 271        }
 272        complete(&rdma->cm_done);
 273        return 0;
 274}
 275
 276static void
 277handle_recv(struct p9_client *client, struct p9_trans_rdma *rdma,
 278            struct p9_rdma_context *c, enum ib_wc_status status, u32 byte_len)
 279{
 280        struct p9_req_t *req;
 281        int err = 0;
 282        int16_t tag;
 283
 284        req = NULL;
 285        ib_dma_unmap_single(rdma->cm_id->device, c->busa, client->msize,
 286                                                         DMA_FROM_DEVICE);
 287
 288        if (status != IB_WC_SUCCESS)
 289                goto err_out;
 290
 291        err = p9_parse_header(c->rc, NULL, NULL, &tag, 1);
 292        if (err)
 293                goto err_out;
 294
 295        req = p9_tag_lookup(client, tag);
 296        if (!req)
 297                goto err_out;
 298
 299        req->rc = c->rc;
 300        req->status = REQ_STATUS_RCVD;
 301        p9_client_cb(client, req);
 302
 303        return;
 304
 305 err_out:
 306        p9_debug(P9_DEBUG_ERROR, "req %p err %d status %d\n", req, err, status);
 307        rdma->state = P9_RDMA_FLUSHING;
 308        client->status = Disconnected;
 309}
 310
 311static void
 312handle_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
 320static void qp_event_handler(struct ib_event *event, void *context)
 321{
 322        p9_debug(P9_DEBUG_ERROR, "QP event %d context %p\n",
 323                 event->event, context);
 324}
 325
 326static 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                        pr_err("unexpected completion type, c->wc_op=%d, wc.opcode=%d, status=%d\n",
 350                               c->wc_op, wc.opcode, wc.status);
 351                        break;
 352                }
 353                kfree(c);
 354        }
 355}
 356
 357static void cq_event_handler(struct ib_event *e, void *v)
 358{
 359        p9_debug(P9_DEBUG_ERROR, "CQ event %d context %p\n", e->event, v);
 360}
 361
 362static void rdma_destroy_trans(struct p9_trans_rdma *rdma)
 363{
 364        if (!rdma)
 365                return;
 366
 367        if (rdma->dma_mr && !IS_ERR(rdma->dma_mr))
 368                ib_dereg_mr(rdma->dma_mr);
 369
 370        if (rdma->qp && !IS_ERR(rdma->qp))
 371                ib_destroy_qp(rdma->qp);
 372
 373        if (rdma->pd && !IS_ERR(rdma->pd))
 374                ib_dealloc_pd(rdma->pd);
 375
 376        if (rdma->cq && !IS_ERR(rdma->cq))
 377                ib_destroy_cq(rdma->cq);
 378
 379        if (rdma->cm_id && !IS_ERR(rdma->cm_id))
 380                rdma_destroy_id(rdma->cm_id);
 381
 382        kfree(rdma);
 383}
 384
 385static int
 386post_recv(struct p9_client *client, struct p9_rdma_context *c)
 387{
 388        struct p9_trans_rdma *rdma = client->trans;
 389        struct ib_recv_wr wr, *bad_wr;
 390        struct ib_sge sge;
 391
 392        c->busa = ib_dma_map_single(rdma->cm_id->device,
 393                                    c->rc->sdata, client->msize,
 394                                    DMA_FROM_DEVICE);
 395        if (ib_dma_mapping_error(rdma->cm_id->device, c->busa))
 396                goto error;
 397
 398        sge.addr = c->busa;
 399        sge.length = client->msize;
 400        sge.lkey = rdma->lkey;
 401
 402        wr.next = NULL;
 403        c->wc_op = IB_WC_RECV;
 404        wr.wr_id = (unsigned long) c;
 405        wr.sg_list = &sge;
 406        wr.num_sge = 1;
 407        return ib_post_recv(rdma->qp, &wr, &bad_wr);
 408
 409 error:
 410        p9_debug(P9_DEBUG_ERROR, "EIO\n");
 411        return -EIO;
 412}
 413
 414static int rdma_request(struct p9_client *client, struct p9_req_t *req)
 415{
 416        struct p9_trans_rdma *rdma = client->trans;
 417        struct ib_send_wr wr, *bad_wr;
 418        struct ib_sge sge;
 419        int err = 0;
 420        unsigned long flags;
 421        struct p9_rdma_context *c = NULL;
 422        struct p9_rdma_context *rpl_context = NULL;
 423
 424        /* Allocate an fcall for the reply */
 425        rpl_context = kmalloc(sizeof *rpl_context, GFP_NOFS);
 426        if (!rpl_context) {
 427                err = -ENOMEM;
 428                goto err_close;
 429        }
 430
 431        /*
 432         * If the request has a buffer, steal it, otherwise
 433         * allocate a new one.  Typically, requests should already
 434         * have receive buffers allocated and just swap them around
 435         */
 436        if (!req->rc) {
 437                req->rc = kmalloc(sizeof(struct p9_fcall)+client->msize,
 438                                  GFP_NOFS);
 439                if (req->rc) {
 440                        req->rc->sdata = (char *) req->rc +
 441                                                sizeof(struct p9_fcall);
 442                        req->rc->capacity = client->msize;
 443                }
 444        }
 445        rpl_context->rc = req->rc;
 446        if (!rpl_context->rc) {
 447                err = -ENOMEM;
 448                goto err_free2;
 449        }
 450
 451        /*
 452         * Post a receive buffer for this request. We need to ensure
 453         * there is a reply buffer available for every outstanding
 454         * request. A flushed request can result in no reply for an
 455         * outstanding request, so we must keep a count to avoid
 456         * overflowing the RQ.
 457         */
 458        if (atomic_inc_return(&rdma->rq_count) <= rdma->rq_depth) {
 459                err = post_recv(client, rpl_context);
 460                if (err)
 461                        goto err_free1;
 462        } else
 463                atomic_dec(&rdma->rq_count);
 464
 465        /* remove posted receive buffer from request structure */
 466        req->rc = NULL;
 467
 468        /* Post the request */
 469        c = kmalloc(sizeof *c, GFP_NOFS);
 470        if (!c) {
 471                err = -ENOMEM;
 472                goto err_free1;
 473        }
 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        kfree(c);
 501        kfree(rpl_context->rc);
 502        kfree(rpl_context);
 503        p9_debug(P9_DEBUG_ERROR, "EIO\n");
 504        return -EIO;
 505 err_free1:
 506        kfree(rpl_context->rc);
 507 err_free2:
 508        kfree(rpl_context);
 509 err_close:
 510        spin_lock_irqsave(&rdma->req_lock, flags);
 511        if (rdma->state < P9_RDMA_CLOSING) {
 512                rdma->state = P9_RDMA_CLOSING;
 513                spin_unlock_irqrestore(&rdma->req_lock, flags);
 514                rdma_disconnect(rdma->cm_id);
 515        } else
 516                spin_unlock_irqrestore(&rdma->req_lock, flags);
 517        return err;
 518}
 519
 520static void rdma_close(struct p9_client *client)
 521{
 522        struct p9_trans_rdma *rdma;
 523
 524        if (!client)
 525                return;
 526
 527        rdma = client->trans;
 528        if (!rdma)
 529                return;
 530
 531        client->status = Disconnected;
 532        rdma_disconnect(rdma->cm_id);
 533        rdma_destroy_trans(rdma);
 534}
 535
 536/**
 537 * alloc_rdma - Allocate and initialize the rdma transport structure
 538 * @opts: Mount options structure
 539 */
 540static struct p9_trans_rdma *alloc_rdma(struct p9_rdma_opts *opts)
 541{
 542        struct p9_trans_rdma *rdma;
 543
 544        rdma = kzalloc(sizeof(struct p9_trans_rdma), GFP_KERNEL);
 545        if (!rdma)
 546                return NULL;
 547
 548        rdma->sq_depth = opts->sq_depth;
 549        rdma->rq_depth = opts->rq_depth;
 550        rdma->timeout = opts->timeout;
 551        spin_lock_init(&rdma->req_lock);
 552        init_completion(&rdma->cm_done);
 553        sema_init(&rdma->sq_sem, rdma->sq_depth);
 554        atomic_set(&rdma->rq_count, 0);
 555
 556        return rdma;
 557}
 558
 559/* its not clear to me we can do anything after send has been posted */
 560static int rdma_cancel(struct p9_client *client, struct p9_req_t *req)
 561{
 562        return 1;
 563}
 564
 565/**
 566 * trans_create_rdma - Transport method for creating atransport instance
 567 * @client: client instance
 568 * @addr: IP address string
 569 * @args: Mount options string
 570 */
 571static int
 572rdma_create_trans(struct p9_client *client, const char *addr, char *args)
 573{
 574        int err;
 575        struct p9_rdma_opts opts;
 576        struct p9_trans_rdma *rdma;
 577        struct rdma_conn_param conn_param;
 578        struct ib_qp_init_attr qp_attr;
 579        struct ib_device_attr devattr;
 580
 581        /* Parse the transport specific mount options */
 582        err = parse_opts(args, &opts);
 583        if (err < 0)
 584                return err;
 585
 586        /* Create and initialize the RDMA transport structure */
 587        rdma = alloc_rdma(&opts);
 588        if (!rdma)
 589                return -ENOMEM;
 590
 591        /* Create the RDMA CM ID */
 592        rdma->cm_id = rdma_create_id(p9_cm_event_handler, client, RDMA_PS_TCP,
 593                                     IB_QPT_RC);
 594        if (IS_ERR(rdma->cm_id))
 595                goto error;
 596
 597        /* Associate the client with the transport */
 598        client->trans = rdma;
 599
 600        /* Resolve the server's address */
 601        rdma->addr.sin_family = AF_INET;
 602        rdma->addr.sin_addr.s_addr = in_aton(addr);
 603        rdma->addr.sin_port = htons(opts.port);
 604        err = rdma_resolve_addr(rdma->cm_id, NULL,
 605                                (struct sockaddr *)&rdma->addr,
 606                                rdma->timeout);
 607        if (err)
 608                goto error;
 609        err = wait_for_completion_interruptible(&rdma->cm_done);
 610        if (err || (rdma->state != P9_RDMA_ADDR_RESOLVED))
 611                goto error;
 612
 613        /* Resolve the route to the server */
 614        err = rdma_resolve_route(rdma->cm_id, rdma->timeout);
 615        if (err)
 616                goto error;
 617        err = wait_for_completion_interruptible(&rdma->cm_done);
 618        if (err || (rdma->state != P9_RDMA_ROUTE_RESOLVED))
 619                goto error;
 620
 621        /* Query the device attributes */
 622        err = ib_query_device(rdma->cm_id->device, &devattr);
 623        if (err)
 624                goto error;
 625
 626        /* Create the Completion Queue */
 627        rdma->cq = ib_create_cq(rdma->cm_id->device, cq_comp_handler,
 628                                cq_event_handler, client,
 629                                opts.sq_depth + opts.rq_depth + 1, 0);
 630        if (IS_ERR(rdma->cq))
 631                goto error;
 632        ib_req_notify_cq(rdma->cq, IB_CQ_NEXT_COMP);
 633
 634        /* Create the Protection Domain */
 635        rdma->pd = ib_alloc_pd(rdma->cm_id->device);
 636        if (IS_ERR(rdma->pd))
 637                goto error;
 638
 639        /* Cache the DMA lkey in the transport */
 640        rdma->dma_mr = NULL;
 641        if (devattr.device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY)
 642                rdma->lkey = rdma->cm_id->device->local_dma_lkey;
 643        else {
 644                rdma->dma_mr = ib_get_dma_mr(rdma->pd, IB_ACCESS_LOCAL_WRITE);
 645                if (IS_ERR(rdma->dma_mr))
 646                        goto error;
 647                rdma->lkey = rdma->dma_mr->lkey;
 648        }
 649
 650        /* Create the Queue Pair */
 651        memset(&qp_attr, 0, sizeof qp_attr);
 652        qp_attr.event_handler = qp_event_handler;
 653        qp_attr.qp_context = client;
 654        qp_attr.cap.max_send_wr = opts.sq_depth;
 655        qp_attr.cap.max_recv_wr = opts.rq_depth;
 656        qp_attr.cap.max_send_sge = P9_RDMA_SEND_SGE;
 657        qp_attr.cap.max_recv_sge = P9_RDMA_RECV_SGE;
 658        qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
 659        qp_attr.qp_type = IB_QPT_RC;
 660        qp_attr.send_cq = rdma->cq;
 661        qp_attr.recv_cq = rdma->cq;
 662        err = rdma_create_qp(rdma->cm_id, rdma->pd, &qp_attr);
 663        if (err)
 664                goto error;
 665        rdma->qp = rdma->cm_id->qp;
 666
 667        /* Request a connection */
 668        memset(&conn_param, 0, sizeof(conn_param));
 669        conn_param.private_data = NULL;
 670        conn_param.private_data_len = 0;
 671        conn_param.responder_resources = P9_RDMA_IRD;
 672        conn_param.initiator_depth = P9_RDMA_ORD;
 673        err = rdma_connect(rdma->cm_id, &conn_param);
 674        if (err)
 675                goto error;
 676        err = wait_for_completion_interruptible(&rdma->cm_done);
 677        if (err || (rdma->state != P9_RDMA_CONNECTED))
 678                goto error;
 679
 680        client->status = Connected;
 681
 682        return 0;
 683
 684error:
 685        rdma_destroy_trans(rdma);
 686        return -ENOTCONN;
 687}
 688
 689static struct p9_trans_module p9_rdma_trans = {
 690        .name = "rdma",
 691        .maxsize = P9_RDMA_MAXSIZE,
 692        .def = 0,
 693        .owner = THIS_MODULE,
 694        .create = rdma_create_trans,
 695        .close = rdma_close,
 696        .request = rdma_request,
 697        .cancel = rdma_cancel,
 698};
 699
 700/**
 701 * p9_trans_rdma_init - Register the 9P RDMA transport driver
 702 */
 703static int __init p9_trans_rdma_init(void)
 704{
 705        v9fs_register_trans(&p9_rdma_trans);
 706        return 0;
 707}
 708
 709static void __exit p9_trans_rdma_exit(void)
 710{
 711        v9fs_unregister_trans(&p9_rdma_trans);
 712}
 713
 714module_init(p9_trans_rdma_init);
 715module_exit(p9_trans_rdma_exit);
 716
 717MODULE_AUTHOR("Tom Tucker <tom@opengridcomputing.com>");
 718MODULE_DESCRIPTION("RDMA Transport for 9P");
 719MODULE_LICENSE("Dual BSD/GPL");
 720
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