root/net/9p/trans_rdma.c

DEFINITIONS

1. p9_rdma_show_options
2. parse_opts
3. p9_cm_event_handler
4. recv_done
5. send_done
6. qp_event_handler
7. rdma_destroy_trans
8. post_recv
9. rdma_request
10. rdma_close
11. alloc_rdma
12. rdma_cancel
13. rdma_cancelled
14. p9_rdma_bind_privport
15. rdma_create_trans
16. p9_trans_rdma_init
17. p9_trans_rdma_exit

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * linux/fs/9p/trans_rdma.c
   4  *
   5  * RDMA transport layer based on the trans_fd.c implementation.
   6  *
   7  *  Copyright (C) 2008 by Tom Tucker <tom@opengridcomputing.com>
   8  *  Copyright (C) 2006 by Russ Cox <rsc@swtch.com>
   9  *  Copyright (C) 2004-2005 by Latchesar Ionkov <lucho@ionkov.net>
  10  *  Copyright (C) 2004-2008 by Eric Van Hensbergen <ericvh@gmail.com>
  11  *  Copyright (C) 1997-2002 by Ron Minnich <rminnich@sarnoff.com>
  12  */
  13 
  14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  15 
  16 #include <linux/in.h>
  17 #include <linux/module.h>
  18 #include <linux/net.h>
  19 #include <linux/ipv6.h>
  20 #include <linux/kthread.h>
  21 #include <linux/errno.h>
  22 #include <linux/kernel.h>
  23 #include <linux/un.h>
  24 #include <linux/uaccess.h>
  25 #include <linux/inet.h>
  26 #include <linux/idr.h>
  27 #include <linux/file.h>
  28 #include <linux/parser.h>
  29 #include <linux/semaphore.h>
  30 #include <linux/slab.h>
  31 #include <linux/seq_file.h>
  32 #include <net/9p/9p.h>
  33 #include <net/9p/client.h>
  34 #include <net/9p/transport.h>
  35 #include <rdma/ib_verbs.h>
  36 #include <rdma/rdma_cm.h>
  37 
  38 #define P9_PORT                 5640
  39 #define P9_RDMA_SQ_DEPTH        32
  40 #define P9_RDMA_RQ_DEPTH        32
  41 #define P9_RDMA_SEND_SGE        4
  42 #define P9_RDMA_RECV_SGE        4
  43 #define P9_RDMA_IRD             0
  44 #define P9_RDMA_ORD             0
  45 #define P9_RDMA_TIMEOUT         30000           /* 30 seconds */
  46 #define P9_RDMA_MAXSIZE         (1024*1024)     /* 1MB */
  47 
  48 /**
  49  * struct p9_trans_rdma - RDMA transport instance
  50  *
  51  * @state: tracks the transport state machine for connection setup and tear down
  52  * @cm_id: The RDMA CM ID
  53  * @pd: Protection Domain pointer
  54  * @qp: Queue Pair pointer
  55  * @cq: Completion Queue pointer
  56  * @timeout: Number of uSecs to wait for connection management events
  57  * @privport: Whether a privileged port may be used
  58  * @port: The port to use
  59  * @sq_depth: The depth of the Send Queue
  60  * @sq_sem: Semaphore for the SQ
  61  * @rq_depth: The depth of the Receive Queue.
  62  * @rq_sem: Semaphore for the RQ
  63  * @excess_rc : Amount of posted Receive Contexts without a pending request.
  64  *              See rdma_request()
  65  * @addr: The remote peer's address
  66  * @req_lock: Protects the active request list
  67  * @cm_done: Completion event for connection management tracking
  68  */
  69 struct p9_trans_rdma {
  70         enum {
  71                 P9_RDMA_INIT,
  72                 P9_RDMA_ADDR_RESOLVED,
  73                 P9_RDMA_ROUTE_RESOLVED,
  74                 P9_RDMA_CONNECTED,
  75                 P9_RDMA_FLUSHING,
  76                 P9_RDMA_CLOSING,
  77                 P9_RDMA_CLOSED,
  78         } state;
  79         struct rdma_cm_id *cm_id;
  80         struct ib_pd *pd;
  81         struct ib_qp *qp;
  82         struct ib_cq *cq;
  83         long timeout;
  84         bool privport;
  85         u16 port;
  86         int sq_depth;
  87         struct semaphore sq_sem;
  88         int rq_depth;
  89         struct semaphore rq_sem;
  90         atomic_t excess_rc;
  91         struct sockaddr_in addr;
  92         spinlock_t req_lock;
  93 
  94         struct completion cm_done;
  95 };
  96 
  97 /**
  98  * p9_rdma_context - Keeps track of in-process WR
  99  *
 100  * @busa: Bus address to unmap when the WR completes
 101  * @req: Keeps track of requests (send)
 102  * @rc: Keepts track of replies (receive)
 103  */
 104 struct p9_rdma_req;
 105 struct p9_rdma_context {
 106         struct ib_cqe cqe;
 107         dma_addr_t busa;
 108         union {
 109                 struct p9_req_t *req;
 110                 struct p9_fcall rc;
 111         };
 112 };
 113 
 114 /**
 115  * p9_rdma_opts - Collection of mount options
 116  * @port: port of connection
 117  * @sq_depth: The requested depth of the SQ. This really doesn't need
 118  * to be any deeper than the number of threads used in the client
 119  * @rq_depth: The depth of the RQ. Should be greater than or equal to SQ depth
 120  * @timeout: Time to wait in msecs for CM events
 121  */
 122 struct p9_rdma_opts {
 123         short port;
 124         bool privport;
 125         int sq_depth;
 126         int rq_depth;
 127         long timeout;
 128 };
 129 
 130 /*
 131  * Option Parsing (code inspired by NFS code)
 132  */
 133 enum {
 134         /* Options that take integer arguments */
 135         Opt_port, Opt_rq_depth, Opt_sq_depth, Opt_timeout,
 136         /* Options that take no argument */
 137         Opt_privport,
 138         Opt_err,
 139 };
 140 
 141 static match_table_t tokens = {
 142         {Opt_port, "port=%u"},
 143         {Opt_sq_depth, "sq=%u"},
 144         {Opt_rq_depth, "rq=%u"},
 145         {Opt_timeout, "timeout=%u"},
 146         {Opt_privport, "privport"},
 147         {Opt_err, NULL},
 148 };
 149 
 150 static int p9_rdma_show_options(struct seq_file *m, struct p9_client *clnt)
 151 {
 152         struct p9_trans_rdma *rdma = clnt->trans;
 153 
 154         if (rdma->port != P9_PORT)
 155                 seq_printf(m, ",port=%u", rdma->port);
 156         if (rdma->sq_depth != P9_RDMA_SQ_DEPTH)
 157                 seq_printf(m, ",sq=%u", rdma->sq_depth);
 158         if (rdma->rq_depth != P9_RDMA_RQ_DEPTH)
 159                 seq_printf(m, ",rq=%u", rdma->rq_depth);
 160         if (rdma->timeout != P9_RDMA_TIMEOUT)
 161                 seq_printf(m, ",timeout=%lu", rdma->timeout);
 162         if (rdma->privport)
 163                 seq_puts(m, ",privport");
 164         return 0;
 165 }
 166 
 167 /**
 168  * parse_opts - parse mount options into rdma options structure
 169  * @params: options string passed from mount
 170  * @opts: rdma transport-specific structure to parse options into
 171  *
 172  * Returns 0 upon success, -ERRNO upon failure
 173  */
 174 static int parse_opts(char *params, struct p9_rdma_opts *opts)
 175 {
 176         char *p;
 177         substring_t args[MAX_OPT_ARGS];
 178         int option;
 179         char *options, *tmp_options;
 180 
 181         opts->port = P9_PORT;
 182         opts->sq_depth = P9_RDMA_SQ_DEPTH;
 183         opts->rq_depth = P9_RDMA_RQ_DEPTH;
 184         opts->timeout = P9_RDMA_TIMEOUT;
 185         opts->privport = false;
 186 
 187         if (!params)
 188                 return 0;
 189 
 190         tmp_options = kstrdup(params, GFP_KERNEL);
 191         if (!tmp_options) {
 192                 p9_debug(P9_DEBUG_ERROR,
 193                          "failed to allocate copy of option string\n");
 194                 return -ENOMEM;
 195         }
 196         options = tmp_options;
 197 
 198         while ((p = strsep(&options, ",")) != NULL) {
 199                 int token;
 200                 int r;
 201                 if (!*p)
 202                         continue;
 203                 token = match_token(p, tokens, args);
 204                 if ((token != Opt_err) && (token != Opt_privport)) {
 205                         r = match_int(&args[0], &option);
 206                         if (r < 0) {
 207                                 p9_debug(P9_DEBUG_ERROR,
 208                                          "integer field, but no integer?\n");
 209                                 continue;
 210                         }
 211                 }
 212                 switch (token) {
 213                 case Opt_port:
 214                         opts->port = option;
 215                         break;
 216                 case Opt_sq_depth:
 217                         opts->sq_depth = option;
 218                         break;
 219                 case Opt_rq_depth:
 220                         opts->rq_depth = option;
 221                         break;
 222                 case Opt_timeout:
 223                         opts->timeout = option;
 224                         break;
 225                 case Opt_privport:
 226                         opts->privport = true;
 227                         break;
 228                 default:
 229                         continue;
 230                 }
 231         }
 232         /* RQ must be at least as large as the SQ */
 233         opts->rq_depth = max(opts->rq_depth, opts->sq_depth);
 234         kfree(tmp_options);
 235         return 0;
 236 }
 237 
 238 static int
 239 p9_cm_event_handler(struct rdma_cm_id *id, struct rdma_cm_event *event)
 240 {
 241         struct p9_client *c = id->context;
 242         struct p9_trans_rdma *rdma = c->trans;
 243         switch (event->event) {
 244         case RDMA_CM_EVENT_ADDR_RESOLVED:
 245                 BUG_ON(rdma->state != P9_RDMA_INIT);
 246                 rdma->state = P9_RDMA_ADDR_RESOLVED;
 247                 break;
 248 
 249         case RDMA_CM_EVENT_ROUTE_RESOLVED:
 250                 BUG_ON(rdma->state != P9_RDMA_ADDR_RESOLVED);
 251                 rdma->state = P9_RDMA_ROUTE_RESOLVED;
 252                 break;
 253 
 254         case RDMA_CM_EVENT_ESTABLISHED:
 255                 BUG_ON(rdma->state != P9_RDMA_ROUTE_RESOLVED);
 256                 rdma->state = P9_RDMA_CONNECTED;
 257                 break;
 258 
 259         case RDMA_CM_EVENT_DISCONNECTED:
 260                 if (rdma)
 261                         rdma->state = P9_RDMA_CLOSED;
 262                 c->status = Disconnected;
 263                 break;
 264 
 265         case RDMA_CM_EVENT_TIMEWAIT_EXIT:
 266                 break;
 267 
 268         case RDMA_CM_EVENT_ADDR_CHANGE:
 269         case RDMA_CM_EVENT_ROUTE_ERROR:
 270         case RDMA_CM_EVENT_DEVICE_REMOVAL:
 271         case RDMA_CM_EVENT_MULTICAST_JOIN:
 272         case RDMA_CM_EVENT_MULTICAST_ERROR:
 273         case RDMA_CM_EVENT_REJECTED:
 274         case RDMA_CM_EVENT_CONNECT_REQUEST:
 275         case RDMA_CM_EVENT_CONNECT_RESPONSE:
 276         case RDMA_CM_EVENT_CONNECT_ERROR:
 277         case RDMA_CM_EVENT_ADDR_ERROR:
 278         case RDMA_CM_EVENT_UNREACHABLE:
 279                 c->status = Disconnected;
 280                 rdma_disconnect(rdma->cm_id);
 281                 break;
 282         default:
 283                 BUG();
 284         }
 285         complete(&rdma->cm_done);
 286         return 0;
 287 }
 288 
 289 static void
 290 recv_done(struct ib_cq *cq, struct ib_wc *wc)
 291 {
 292         struct p9_client *client = cq->cq_context;
 293         struct p9_trans_rdma *rdma = client->trans;
 294         struct p9_rdma_context *c =
 295                 container_of(wc->wr_cqe, struct p9_rdma_context, cqe);
 296         struct p9_req_t *req;
 297         int err = 0;
 298         int16_t tag;
 299 
 300         req = NULL;
 301         ib_dma_unmap_single(rdma->cm_id->device, c->busa, client->msize,
 302                                                          DMA_FROM_DEVICE);
 303 
 304         if (wc->status != IB_WC_SUCCESS)
 305                 goto err_out;
 306 
 307         c->rc.size = wc->byte_len;
 308         err = p9_parse_header(&c->rc, NULL, NULL, &tag, 1);
 309         if (err)
 310                 goto err_out;
 311 
 312         req = p9_tag_lookup(client, tag);
 313         if (!req)
 314                 goto err_out;
 315 
 316         /* Check that we have not yet received a reply for this request.
 317          */
 318         if (unlikely(req->rc.sdata)) {
 319                 pr_err("Duplicate reply for request %d", tag);
 320                 goto err_out;
 321         }
 322 
 323         req->rc.size = c->rc.size;
 324         req->rc.sdata = c->rc.sdata;
 325         p9_client_cb(client, req, REQ_STATUS_RCVD);
 326 
 327  out:
 328         up(&rdma->rq_sem);
 329         kfree(c);
 330         return;
 331 
 332  err_out:
 333         p9_debug(P9_DEBUG_ERROR, "req %p err %d status %d\n",
 334                         req, err, wc->status);
 335         rdma->state = P9_RDMA_FLUSHING;
 336         client->status = Disconnected;
 337         goto out;
 338 }
 339 
 340 static void
 341 send_done(struct ib_cq *cq, struct ib_wc *wc)
 342 {
 343         struct p9_client *client = cq->cq_context;
 344         struct p9_trans_rdma *rdma = client->trans;
 345         struct p9_rdma_context *c =
 346                 container_of(wc->wr_cqe, struct p9_rdma_context, cqe);
 347 
 348         ib_dma_unmap_single(rdma->cm_id->device,
 349                             c->busa, c->req->tc.size,
 350                             DMA_TO_DEVICE);
 351         up(&rdma->sq_sem);
 352         p9_req_put(c->req);
 353         kfree(c);
 354 }
 355 
 356 static void qp_event_handler(struct ib_event *event, void *context)
 357 {
 358         p9_debug(P9_DEBUG_ERROR, "QP event %d context %p\n",
 359                  event->event, context);
 360 }
 361 
 362 static void rdma_destroy_trans(struct p9_trans_rdma *rdma)
 363 {
 364         if (!rdma)
 365                 return;
 366 
 367         if (rdma->qp && !IS_ERR(rdma->qp))
 368                 ib_destroy_qp(rdma->qp);
 369 
 370         if (rdma->pd && !IS_ERR(rdma->pd))
 371                 ib_dealloc_pd(rdma->pd);
 372 
 373         if (rdma->cq && !IS_ERR(rdma->cq))
 374                 ib_free_cq(rdma->cq);
 375 
 376         if (rdma->cm_id && !IS_ERR(rdma->cm_id))
 377                 rdma_destroy_id(rdma->cm_id);
 378 
 379         kfree(rdma);
 380 }
 381 
 382 static int
 383 post_recv(struct p9_client *client, struct p9_rdma_context *c)
 384 {
 385         struct p9_trans_rdma *rdma = client->trans;
 386         struct ib_recv_wr wr;
 387         struct ib_sge sge;
 388 
 389         c->busa = ib_dma_map_single(rdma->cm_id->device,
 390                                     c->rc.sdata, client->msize,
 391                                     DMA_FROM_DEVICE);
 392         if (ib_dma_mapping_error(rdma->cm_id->device, c->busa))
 393                 goto error;
 394 
 395         c->cqe.done = recv_done;
 396 
 397         sge.addr = c->busa;
 398         sge.length = client->msize;
 399         sge.lkey = rdma->pd->local_dma_lkey;
 400 
 401         wr.next = NULL;
 402         wr.wr_cqe = &c->cqe;
 403         wr.sg_list = &sge;
 404         wr.num_sge = 1;
 405         return ib_post_recv(rdma->qp, &wr, NULL);
 406 
 407  error:
 408         p9_debug(P9_DEBUG_ERROR, "EIO\n");
 409         return -EIO;
 410 }
 411 
 412 static int rdma_request(struct p9_client *client, struct p9_req_t *req)
 413 {
 414         struct p9_trans_rdma *rdma = client->trans;
 415         struct ib_send_wr wr;
 416         struct ib_sge sge;
 417         int err = 0;
 418         unsigned long flags;
 419         struct p9_rdma_context *c = NULL;
 420         struct p9_rdma_context *rpl_context = NULL;
 421 
 422         /* When an error occurs between posting the recv and the send,
 423          * there will be a receive context posted without a pending request.
 424          * Since there is no way to "un-post" it, we remember it and skip
 425          * post_recv() for the next request.
 426          * So here,
 427          * see if we are this `next request' and need to absorb an excess rc.
 428          * If yes, then drop and free our own, and do not recv_post().
 429          **/
 430         if (unlikely(atomic_read(&rdma->excess_rc) > 0)) {
 431                 if ((atomic_sub_return(1, &rdma->excess_rc) >= 0)) {
 432                         /* Got one! */
 433                         p9_fcall_fini(&req->rc);
 434                         req->rc.sdata = NULL;
 435                         goto dont_need_post_recv;
 436                 } else {
 437                         /* We raced and lost. */
 438                         atomic_inc(&rdma->excess_rc);
 439                 }
 440         }
 441 
 442         /* Allocate an fcall for the reply */
 443         rpl_context = kmalloc(sizeof *rpl_context, GFP_NOFS);
 444         if (!rpl_context) {
 445                 err = -ENOMEM;
 446                 goto recv_error;
 447         }
 448         rpl_context->rc.sdata = req->rc.sdata;
 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 (down_interruptible(&rdma->rq_sem)) {
 458                 err = -EINTR;
 459                 goto recv_error;
 460         }
 461 
 462         err = post_recv(client, rpl_context);
 463         if (err) {
 464                 p9_debug(P9_DEBUG_ERROR, "POST RECV failed: %d\n", err);
 465                 goto recv_error;
 466         }
 467         /* remove posted receive buffer from request structure */
 468         req->rc.sdata = NULL;
 469 
 470 dont_need_post_recv:
 471         /* Post the request */
 472         c = kmalloc(sizeof *c, GFP_NOFS);
 473         if (!c) {
 474                 err = -ENOMEM;
 475                 goto send_error;
 476         }
 477         c->req = req;
 478 
 479         c->busa = ib_dma_map_single(rdma->cm_id->device,
 480                                     c->req->tc.sdata, c->req->tc.size,
 481                                     DMA_TO_DEVICE);
 482         if (ib_dma_mapping_error(rdma->cm_id->device, c->busa)) {
 483                 err = -EIO;
 484                 goto send_error;
 485         }
 486 
 487         c->cqe.done = send_done;
 488 
 489         sge.addr = c->busa;
 490         sge.length = c->req->tc.size;
 491         sge.lkey = rdma->pd->local_dma_lkey;
 492 
 493         wr.next = NULL;
 494         wr.wr_cqe = &c->cqe;
 495         wr.opcode = IB_WR_SEND;
 496         wr.send_flags = IB_SEND_SIGNALED;
 497         wr.sg_list = &sge;
 498         wr.num_sge = 1;
 499 
 500         if (down_interruptible(&rdma->sq_sem)) {
 501                 err = -EINTR;
 502                 goto send_error;
 503         }
 504 
 505         /* Mark request as `sent' *before* we actually send it,
 506          * because doing if after could erase the REQ_STATUS_RCVD
 507          * status in case of a very fast reply.
 508          */
 509         req->status = REQ_STATUS_SENT;
 510         err = ib_post_send(rdma->qp, &wr, NULL);
 511         if (err)
 512                 goto send_error;
 513 
 514         /* Success */
 515         return 0;
 516 
 517  /* Handle errors that happened during or while preparing the send: */
 518  send_error:
 519         req->status = REQ_STATUS_ERROR;
 520         kfree(c);
 521         p9_debug(P9_DEBUG_ERROR, "Error %d in rdma_request()\n", err);
 522 
 523         /* Ach.
 524          *  We did recv_post(), but not send. We have one recv_post in excess.
 525          */
 526         atomic_inc(&rdma->excess_rc);
 527         return err;
 528 
 529  /* Handle errors that happened during or while preparing post_recv(): */
 530  recv_error:
 531         kfree(rpl_context);
 532         spin_lock_irqsave(&rdma->req_lock, flags);
 533         if (err != -EINTR && rdma->state < P9_RDMA_CLOSING) {
 534                 rdma->state = P9_RDMA_CLOSING;
 535                 spin_unlock_irqrestore(&rdma->req_lock, flags);
 536                 rdma_disconnect(rdma->cm_id);
 537         } else
 538                 spin_unlock_irqrestore(&rdma->req_lock, flags);
 539         return err;
 540 }
 541 
 542 static void rdma_close(struct p9_client *client)
 543 {
 544         struct p9_trans_rdma *rdma;
 545 
 546         if (!client)
 547                 return;
 548 
 549         rdma = client->trans;
 550         if (!rdma)
 551                 return;
 552 
 553         client->status = Disconnected;
 554         rdma_disconnect(rdma->cm_id);
 555         rdma_destroy_trans(rdma);
 556 }
 557 
 558 /**
 559  * alloc_rdma - Allocate and initialize the rdma transport structure
 560  * @opts: Mount options structure
 561  */
 562 static struct p9_trans_rdma *alloc_rdma(struct p9_rdma_opts *opts)
 563 {
 564         struct p9_trans_rdma *rdma;
 565 
 566         rdma = kzalloc(sizeof(struct p9_trans_rdma), GFP_KERNEL);
 567         if (!rdma)
 568                 return NULL;
 569 
 570         rdma->port = opts->port;
 571         rdma->privport = opts->privport;
 572         rdma->sq_depth = opts->sq_depth;
 573         rdma->rq_depth = opts->rq_depth;
 574         rdma->timeout = opts->timeout;
 575         spin_lock_init(&rdma->req_lock);
 576         init_completion(&rdma->cm_done);
 577         sema_init(&rdma->sq_sem, rdma->sq_depth);
 578         sema_init(&rdma->rq_sem, rdma->rq_depth);
 579         atomic_set(&rdma->excess_rc, 0);
 580 
 581         return rdma;
 582 }
 583 
 584 static int rdma_cancel(struct p9_client *client, struct p9_req_t *req)
 585 {
 586         /* Nothing to do here.
 587          * We will take care of it (if we have to) in rdma_cancelled()
 588          */
 589         return 1;
 590 }
 591 
 592 /* A request has been fully flushed without a reply.
 593  * That means we have posted one buffer in excess.
 594  */
 595 static int rdma_cancelled(struct p9_client *client, struct p9_req_t *req)
 596 {
 597         struct p9_trans_rdma *rdma = client->trans;
 598         atomic_inc(&rdma->excess_rc);
 599         return 0;
 600 }
 601 
 602 static int p9_rdma_bind_privport(struct p9_trans_rdma *rdma)
 603 {
 604         struct sockaddr_in cl = {
 605                 .sin_family = AF_INET,
 606                 .sin_addr.s_addr = htonl(INADDR_ANY),
 607         };
 608         int port, err = -EINVAL;
 609 
 610         for (port = P9_DEF_MAX_RESVPORT; port >= P9_DEF_MIN_RESVPORT; port--) {
 611                 cl.sin_port = htons((ushort)port);
 612                 err = rdma_bind_addr(rdma->cm_id, (struct sockaddr *)&cl);
 613                 if (err != -EADDRINUSE)
 614                         break;
 615         }
 616         return err;
 617 }
 618 
 619 /**
 620  * rdma_create_trans - Transport method for creating a transport instance
 621  * @client: client instance
 622  * @addr: IP address string
 623  * @args: Mount options string
 624  */
 625 static int
 626 rdma_create_trans(struct p9_client *client, const char *addr, char *args)
 627 {
 628         int err;
 629         struct p9_rdma_opts opts;
 630         struct p9_trans_rdma *rdma;
 631         struct rdma_conn_param conn_param;
 632         struct ib_qp_init_attr qp_attr;
 633 
 634         if (addr == NULL)
 635                 return -EINVAL;
 636 
 637         /* Parse the transport specific mount options */
 638         err = parse_opts(args, &opts);
 639         if (err < 0)
 640                 return err;
 641 
 642         /* Create and initialize the RDMA transport structure */
 643         rdma = alloc_rdma(&opts);
 644         if (!rdma)
 645                 return -ENOMEM;
 646 
 647         /* Create the RDMA CM ID */
 648         rdma->cm_id = rdma_create_id(&init_net, p9_cm_event_handler, client,
 649                                      RDMA_PS_TCP, IB_QPT_RC);
 650         if (IS_ERR(rdma->cm_id))
 651                 goto error;
 652 
 653         /* Associate the client with the transport */
 654         client->trans = rdma;
 655 
 656         /* Bind to a privileged port if we need to */
 657         if (opts.privport) {
 658                 err = p9_rdma_bind_privport(rdma);
 659                 if (err < 0) {
 660                         pr_err("%s (%d): problem binding to privport: %d\n",
 661                                __func__, task_pid_nr(current), -err);
 662                         goto error;
 663                 }
 664         }
 665 
 666         /* Resolve the server's address */
 667         rdma->addr.sin_family = AF_INET;
 668         rdma->addr.sin_addr.s_addr = in_aton(addr);
 669         rdma->addr.sin_port = htons(opts.port);
 670         err = rdma_resolve_addr(rdma->cm_id, NULL,
 671                                 (struct sockaddr *)&rdma->addr,
 672                                 rdma->timeout);
 673         if (err)
 674                 goto error;
 675         err = wait_for_completion_interruptible(&rdma->cm_done);
 676         if (err || (rdma->state != P9_RDMA_ADDR_RESOLVED))
 677                 goto error;
 678 
 679         /* Resolve the route to the server */
 680         err = rdma_resolve_route(rdma->cm_id, rdma->timeout);
 681         if (err)
 682                 goto error;
 683         err = wait_for_completion_interruptible(&rdma->cm_done);
 684         if (err || (rdma->state != P9_RDMA_ROUTE_RESOLVED))
 685                 goto error;
 686 
 687         /* Create the Completion Queue */
 688         rdma->cq = ib_alloc_cq_any(rdma->cm_id->device, client,
 689                                    opts.sq_depth + opts.rq_depth + 1,
 690                                    IB_POLL_SOFTIRQ);
 691         if (IS_ERR(rdma->cq))
 692                 goto error;
 693 
 694         /* Create the Protection Domain */
 695         rdma->pd = ib_alloc_pd(rdma->cm_id->device, 0);
 696         if (IS_ERR(rdma->pd))
 697                 goto error;
 698 
 699         /* Create the Queue Pair */
 700         memset(&qp_attr, 0, sizeof qp_attr);
 701         qp_attr.event_handler = qp_event_handler;
 702         qp_attr.qp_context = client;
 703         qp_attr.cap.max_send_wr = opts.sq_depth;
 704         qp_attr.cap.max_recv_wr = opts.rq_depth;
 705         qp_attr.cap.max_send_sge = P9_RDMA_SEND_SGE;
 706         qp_attr.cap.max_recv_sge = P9_RDMA_RECV_SGE;
 707         qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
 708         qp_attr.qp_type = IB_QPT_RC;
 709         qp_attr.send_cq = rdma->cq;
 710         qp_attr.recv_cq = rdma->cq;
 711         err = rdma_create_qp(rdma->cm_id, rdma->pd, &qp_attr);
 712         if (err)
 713                 goto error;
 714         rdma->qp = rdma->cm_id->qp;
 715 
 716         /* Request a connection */
 717         memset(&conn_param, 0, sizeof(conn_param));
 718         conn_param.private_data = NULL;
 719         conn_param.private_data_len = 0;
 720         conn_param.responder_resources = P9_RDMA_IRD;
 721         conn_param.initiator_depth = P9_RDMA_ORD;
 722         err = rdma_connect(rdma->cm_id, &conn_param);
 723         if (err)
 724                 goto error;
 725         err = wait_for_completion_interruptible(&rdma->cm_done);
 726         if (err || (rdma->state != P9_RDMA_CONNECTED))
 727                 goto error;
 728 
 729         client->status = Connected;
 730 
 731         return 0;
 732 
 733 error:
 734         rdma_destroy_trans(rdma);
 735         return -ENOTCONN;
 736 }
 737 
 738 static struct p9_trans_module p9_rdma_trans = {
 739         .name = "rdma",
 740         .maxsize = P9_RDMA_MAXSIZE,
 741         .def = 0,
 742         .owner = THIS_MODULE,
 743         .create = rdma_create_trans,
 744         .close = rdma_close,
 745         .request = rdma_request,
 746         .cancel = rdma_cancel,
 747         .cancelled = rdma_cancelled,
 748         .show_options = p9_rdma_show_options,
 749 };
 750 
 751 /**
 752  * p9_trans_rdma_init - Register the 9P RDMA transport driver
 753  */
 754 static int __init p9_trans_rdma_init(void)
 755 {
 756         v9fs_register_trans(&p9_rdma_trans);
 757         return 0;
 758 }
 759 
 760 static void __exit p9_trans_rdma_exit(void)
 761 {
 762         v9fs_unregister_trans(&p9_rdma_trans);
 763 }
 764 
 765 module_init(p9_trans_rdma_init);
 766 module_exit(p9_trans_rdma_exit);
 767 
 768 MODULE_AUTHOR("Tom Tucker <tom@opengridcomputing.com>");
 769 MODULE_DESCRIPTION("RDMA Transport for 9P");
 770 MODULE_LICENSE("Dual BSD/GPL");