Merge tag '9p-for-5.3' of git://github.com/martinetd/linux
[sfrench/cifs-2.6.git] / net / 9p / trans_rdma.c
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(rdma->cm_id->device, client,
689                         opts.sq_depth + opts.rq_depth + 1,
690                         0, 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");