Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland...
[linux-2.6.git] / 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 <linux/slab.h>
44 #include <net/9p/9p.h>
45 #include <net/9p/client.h>
46 #include <net/9p/transport.h>
47 #include <rdma/ib_verbs.h>
48 #include <rdma/rdma_cm.h>
49
50 #define P9_PORT                 5640
51 #define P9_RDMA_SQ_DEPTH        32
52 #define P9_RDMA_RQ_DEPTH        32
53 #define P9_RDMA_SEND_SGE        4
54 #define P9_RDMA_RECV_SGE        4
55 #define P9_RDMA_IRD             0
56 #define P9_RDMA_ORD             0
57 #define P9_RDMA_TIMEOUT         30000           /* 30 seconds */
58 #define P9_RDMA_MAXSIZE         (4*4096)        /* Min SGE is 4, so we can
59                                                  * safely advertise a maxsize
60                                                  * of 64k */
61
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  * @dm_mr: DMA Memory Region pointer
71  * @lkey: The local access only memory region key
72  * @timeout: Number of uSecs to wait for connection management events
73  * @sq_depth: The depth of the Send Queue
74  * @sq_sem: Semaphore for the SQ
75  * @rq_depth: The depth of the Receive Queue.
76  * @rq_count: Count of requests in the Receive Queue.
77  * @addr: The remote peer's address
78  * @req_lock: Protects the active request list
79  * @cm_done: Completion event for connection management tracking
80  */
81 struct p9_trans_rdma {
82         enum {
83                 P9_RDMA_INIT,
84                 P9_RDMA_ADDR_RESOLVED,
85                 P9_RDMA_ROUTE_RESOLVED,
86                 P9_RDMA_CONNECTED,
87                 P9_RDMA_FLUSHING,
88                 P9_RDMA_CLOSING,
89                 P9_RDMA_CLOSED,
90         } state;
91         struct rdma_cm_id *cm_id;
92         struct ib_pd *pd;
93         struct ib_qp *qp;
94         struct ib_cq *cq;
95         struct ib_mr *dma_mr;
96         u32 lkey;
97         long timeout;
98         int sq_depth;
99         struct semaphore sq_sem;
100         int rq_depth;
101         atomic_t rq_count;
102         struct sockaddr_in addr;
103         spinlock_t req_lock;
104
105         struct completion cm_done;
106 };
107
108 /**
109  * p9_rdma_context - Keeps track of in-process WR
110  *
111  * @wc_op: The original WR op for when the CQE completes in error.
112  * @busa: Bus address to unmap when the WR completes
113  * @req: Keeps track of requests (send)
114  * @rc: Keepts track of replies (receive)
115  */
116 struct p9_rdma_req;
117 struct p9_rdma_context {
118         enum ib_wc_opcode wc_op;
119         dma_addr_t busa;
120         union {
121                 struct p9_req_t *req;
122                 struct p9_fcall *rc;
123         };
124 };
125
126 /**
127  * p9_rdma_opts - Collection of mount options
128  * @port: port of connection
129  * @sq_depth: The requested depth of the SQ. This really doesn't need
130  * to be any deeper than the number of threads used in the client
131  * @rq_depth: The depth of the RQ. Should be greater than or equal to SQ depth
132  * @timeout: Time to wait in msecs for CM events
133  */
134 struct p9_rdma_opts {
135         short port;
136         int sq_depth;
137         int rq_depth;
138         long timeout;
139 };
140
141 /*
142  * Option Parsing (code inspired by NFS code)
143  */
144 enum {
145         /* Options that take integer arguments */
146         Opt_port, Opt_rq_depth, Opt_sq_depth, Opt_timeout, Opt_err,
147 };
148
149 static match_table_t tokens = {
150         {Opt_port, "port=%u"},
151         {Opt_sq_depth, "sq=%u"},
152         {Opt_rq_depth, "rq=%u"},
153         {Opt_timeout, "timeout=%u"},
154         {Opt_err, NULL},
155 };
156
157 /**
158  * parse_opts - parse mount options into rdma options structure
159  * @params: options string passed from mount
160  * @opts: rdma transport-specific structure to parse options into
161  *
162  * Returns 0 upon success, -ERRNO upon failure
163  */
164 static int parse_opts(char *params, struct p9_rdma_opts *opts)
165 {
166         char *p;
167         substring_t args[MAX_OPT_ARGS];
168         int option;
169         char *options, *tmp_options;
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         tmp_options = kstrdup(params, GFP_KERNEL);
180         if (!tmp_options) {
181                 P9_DPRINTK(P9_DEBUG_ERROR,
182                            "failed to allocate copy of option string\n");
183                 return -ENOMEM;
184         }
185         options = tmp_options;
186
187         while ((p = strsep(&options, ",")) != NULL) {
188                 int token;
189                 int r;
190                 if (!*p)
191                         continue;
192                 token = match_token(p, tokens, args);
193                 r = match_int(&args[0], &option);
194                 if (r < 0) {
195                         P9_DPRINTK(P9_DEBUG_ERROR,
196                                    "integer field, but no integer?\n");
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(tmp_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 }
309
310 static void
311 handle_send(struct p9_client *client, struct p9_trans_rdma *rdma,
312             struct p9_rdma_context *c, enum ib_wc_status status, u32 byte_len)
313 {
314         ib_dma_unmap_single(rdma->cm_id->device,
315                             c->busa, c->req->tc->size,
316                             DMA_TO_DEVICE);
317 }
318
319 static void qp_event_handler(struct ib_event *event, void *context)
320 {
321         P9_DPRINTK(P9_DEBUG_ERROR, "QP event %d context %p\n", event->event,
322                                                                 context);
323 }
324
325 static void cq_comp_handler(struct ib_cq *cq, void *cq_context)
326 {
327         struct p9_client *client = cq_context;
328         struct p9_trans_rdma *rdma = client->trans;
329         int ret;
330         struct ib_wc wc;
331
332         ib_req_notify_cq(rdma->cq, IB_CQ_NEXT_COMP);
333         while ((ret = ib_poll_cq(cq, 1, &wc)) > 0) {
334                 struct p9_rdma_context *c = (void *) (unsigned long) wc.wr_id;
335
336                 switch (c->wc_op) {
337                 case IB_WC_RECV:
338                         atomic_dec(&rdma->rq_count);
339                         handle_recv(client, rdma, c, wc.status, wc.byte_len);
340                         break;
341
342                 case IB_WC_SEND:
343                         handle_send(client, rdma, c, wc.status, wc.byte_len);
344                         up(&rdma->sq_sem);
345                         break;
346
347                 default:
348                         printk(KERN_ERR "9prdma: unexpected completion type, "
349                                "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
357 static void cq_event_handler(struct ib_event *e, void *v)
358 {
359         P9_DPRINTK(P9_DEBUG_ERROR, "CQ event %d context %p\n", e->event, v);
360 }
361
362 static 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
385 static int
386 post_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_DPRINTK(P9_DEBUG_ERROR, "EIO\n");
411         return -EIO;
412 }
413
414 static 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_DPRINTK(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
520 static 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  */
540 static 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 */
560 static 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  */
571 static int
572 rdma_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
684 error:
685         rdma_destroy_trans(rdma);
686         return -ENOTCONN;
687 }
688
689 static 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  */
703 static int __init p9_trans_rdma_init(void)
704 {
705         v9fs_register_trans(&p9_rdma_trans);
706         return 0;
707 }
708
709 static void __exit p9_trans_rdma_exit(void)
710 {
711         v9fs_unregister_trans(&p9_rdma_trans);
712 }
713
714 module_init(p9_trans_rdma_init);
715 module_exit(p9_trans_rdma_exit);
716
717 MODULE_AUTHOR("Tom Tucker <tom@opengridcomputing.com>");
718 MODULE_DESCRIPTION("RDMA Transport for 9P");
719 MODULE_LICENSE("Dual BSD/GPL");