1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * RDMA transport layer based on the trans_fd.c implementation.
4 *
5 *  Copyright (C) 2008 by Tom Tucker <tom@opengridcomputing.com>
6 *  Copyright (C) 2006 by Russ Cox <rsc@swtch.com>
7 *  Copyright (C) 2004-2005 by Latchesar Ionkov <lucho@ionkov.net>
8 *  Copyright (C) 2004-2008 by Eric Van Hensbergen <ericvh@gmail.com>
9 *  Copyright (C) 1997-2002 by Ron Minnich <rminnich@sarnoff.com>
10 */
11
12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14#include <linux/in.h>
15#include <linux/module.h>
16#include <linux/net.h>
17#include <linux/ipv6.h>
18#include <linux/kthread.h>
19#include <linux/errno.h>
20#include <linux/kernel.h>
21#include <linux/un.h>
22#include <linux/uaccess.h>
23#include <linux/inet.h>
24#include <linux/file.h>
25#include <linux/parser.h>
26#include <linux/semaphore.h>
27#include <linux/slab.h>
28#include <linux/seq_file.h>
29#include <net/9p/9p.h>
30#include <net/9p/client.h>
31#include <net/9p/transport.h>
32#include <rdma/ib_verbs.h>
33#include <rdma/rdma_cm.h>
34
35#define P9_PORT			5640
36#define P9_RDMA_SQ_DEPTH	32
37#define P9_RDMA_RQ_DEPTH	32
38#define P9_RDMA_SEND_SGE	4
39#define P9_RDMA_RECV_SGE	4
40#define P9_RDMA_IRD		0
41#define P9_RDMA_ORD		0
42#define P9_RDMA_TIMEOUT		30000		/* 30 seconds */
43#define P9_RDMA_MAXSIZE		(1024*1024)	/* 1MB */
44
45/**
46 * struct p9_trans_rdma - RDMA transport instance
47 *
48 * @state: tracks the transport state machine for connection setup and tear down
49 * @cm_id: The RDMA CM ID
50 * @pd: Protection Domain pointer
51 * @qp: Queue Pair pointer
52 * @cq: Completion Queue pointer
53 * @timeout: Number of uSecs to wait for connection management events
54 * @privport: Whether a privileged port may be used
55 * @port: The port to use
56 * @sq_depth: The depth of the Send Queue
57 * @sq_sem: Semaphore for the SQ
58 * @rq_depth: The depth of the Receive Queue.
59 * @rq_sem: Semaphore for the RQ
60 * @excess_rc : Amount of posted Receive Contexts without a pending request.
61 *		See rdma_request()
62 * @addr: The remote peer's address
63 * @req_lock: Protects the active request list
64 * @cm_done: Completion event for connection management tracking
65 */
66struct p9_trans_rdma {
67	enum {
68		P9_RDMA_INIT,
69		P9_RDMA_ADDR_RESOLVED,
70		P9_RDMA_ROUTE_RESOLVED,
71		P9_RDMA_CONNECTED,
72		P9_RDMA_FLUSHING,
73		P9_RDMA_CLOSING,
74		P9_RDMA_CLOSED,
75	} state;
76	struct rdma_cm_id *cm_id;
77	struct ib_pd *pd;
78	struct ib_qp *qp;
79	struct ib_cq *cq;
80	long timeout;
81	bool privport;
82	u16 port;
83	int sq_depth;
84	struct semaphore sq_sem;
85	int rq_depth;
86	struct semaphore rq_sem;
87	atomic_t excess_rc;
88	struct sockaddr_in addr;
89	spinlock_t req_lock;
90
91	struct completion cm_done;
92};
93
94struct p9_rdma_req;
95
96/**
97 * struct p9_rdma_context - Keeps track of in-process WR
98 *
99 * @cqe: completion queue entry
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 */
104struct p9_rdma_context {
105	struct ib_cqe cqe;
106	dma_addr_t busa;
107	union {
108		struct p9_req_t *req;
109		struct p9_fcall rc;
110	};
111};
112
113/**
114 * struct p9_rdma_opts - Collection of mount options
115 * @port: port of connection
116 * @privport: Whether a privileged port may be used
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 */
122struct 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 */
133enum {
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
141static 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
150static 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 */
174static 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
238static int
239p9_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
289static void
290recv_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
340static void
341send_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(client, c->req);
353	kfree(c);
354}
355
356static 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
362static 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
382static int
383post_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	int ret;
389
390	c->busa = ib_dma_map_single(rdma->cm_id->device,
391				    c->rc.sdata, client->msize,
392				    DMA_FROM_DEVICE);
393	if (ib_dma_mapping_error(rdma->cm_id->device, c->busa))
394		goto error;
395
396	c->cqe.done = recv_done;
397
398	sge.addr = c->busa;
399	sge.length = client->msize;
400	sge.lkey = rdma->pd->local_dma_lkey;
401
402	wr.next = NULL;
403	wr.wr_cqe = &c->cqe;
404	wr.sg_list = &sge;
405	wr.num_sge = 1;
406
407	ret = ib_post_recv(rdma->qp, &wr, NULL);
408	if (ret)
409		ib_dma_unmap_single(rdma->cm_id->device, c->busa,
410				    client->msize, DMA_FROM_DEVICE);
411	return ret;
412
413 error:
414	p9_debug(P9_DEBUG_ERROR, "EIO\n");
415	return -EIO;
416}
417
418static int rdma_request(struct p9_client *client, struct p9_req_t *req)
419{
420	struct p9_trans_rdma *rdma = client->trans;
421	struct ib_send_wr wr;
422	struct ib_sge sge;
423	int err = 0;
424	unsigned long flags;
425	struct p9_rdma_context *c = NULL;
426	struct p9_rdma_context *rpl_context = NULL;
427
428	/* When an error occurs between posting the recv and the send,
429	 * there will be a receive context posted without a pending request.
430	 * Since there is no way to "un-post" it, we remember it and skip
431	 * post_recv() for the next request.
432	 * So here,
433	 * see if we are this `next request' and need to absorb an excess rc.
434	 * If yes, then drop and free our own, and do not recv_post().
435	 **/
436	if (unlikely(atomic_read(&rdma->excess_rc) > 0)) {
437		if ((atomic_sub_return(1, &rdma->excess_rc) >= 0)) {
438			/* Got one! */
439			p9_fcall_fini(&req->rc);
440			req->rc.sdata = NULL;
441			goto dont_need_post_recv;
442		} else {
443			/* We raced and lost. */
444			atomic_inc(&rdma->excess_rc);
445		}
446	}
447
448	/* Allocate an fcall for the reply */
449	rpl_context = kmalloc(sizeof *rpl_context, GFP_NOFS);
450	if (!rpl_context) {
451		err = -ENOMEM;
452		goto recv_error;
453	}
454	rpl_context->rc.sdata = req->rc.sdata;
455
456	/*
457	 * Post a receive buffer for this request. We need to ensure
458	 * there is a reply buffer available for every outstanding
459	 * request. A flushed request can result in no reply for an
460	 * outstanding request, so we must keep a count to avoid
461	 * overflowing the RQ.
462	 */
463	if (down_interruptible(&rdma->rq_sem)) {
464		err = -EINTR;
465		goto recv_error;
466	}
467
468	err = post_recv(client, rpl_context);
469	if (err) {
470		p9_debug(P9_DEBUG_ERROR, "POST RECV failed: %d\n", err);
471		goto recv_error;
472	}
473	/* remove posted receive buffer from request structure */
474	req->rc.sdata = NULL;
475
476dont_need_post_recv:
477	/* Post the request */
478	c = kmalloc(sizeof *c, GFP_NOFS);
479	if (!c) {
480		err = -ENOMEM;
481		goto send_error;
482	}
483	c->req = req;
484
485	c->busa = ib_dma_map_single(rdma->cm_id->device,
486				    c->req->tc.sdata, c->req->tc.size,
487				    DMA_TO_DEVICE);
488	if (ib_dma_mapping_error(rdma->cm_id->device, c->busa)) {
489		err = -EIO;
490		goto send_error;
491	}
492
493	c->cqe.done = send_done;
494
495	sge.addr = c->busa;
496	sge.length = c->req->tc.size;
497	sge.lkey = rdma->pd->local_dma_lkey;
498
499	wr.next = NULL;
500	wr.wr_cqe = &c->cqe;
501	wr.opcode = IB_WR_SEND;
502	wr.send_flags = IB_SEND_SIGNALED;
503	wr.sg_list = &sge;
504	wr.num_sge = 1;
505
506	if (down_interruptible(&rdma->sq_sem)) {
507		err = -EINTR;
508		goto dma_unmap;
509	}
510
511	/* Mark request as `sent' *before* we actually send it,
512	 * because doing if after could erase the REQ_STATUS_RCVD
513	 * status in case of a very fast reply.
514	 */
515	WRITE_ONCE(req->status, REQ_STATUS_SENT);
516	err = ib_post_send(rdma->qp, &wr, NULL);
517	if (err)
518		goto dma_unmap;
519
520	/* Success */
521	return 0;
522
523dma_unmap:
524	ib_dma_unmap_single(rdma->cm_id->device, c->busa,
525			    c->req->tc.size, DMA_TO_DEVICE);
526 /* Handle errors that happened during or while preparing the send: */
527 send_error:
528	WRITE_ONCE(req->status, REQ_STATUS_ERROR);
529	kfree(c);
530	p9_debug(P9_DEBUG_ERROR, "Error %d in rdma_request()\n", err);
531
532	/* Ach.
533	 *  We did recv_post(), but not send. We have one recv_post in excess.
534	 */
535	atomic_inc(&rdma->excess_rc);
536	return err;
537
538 /* Handle errors that happened during or while preparing post_recv(): */
539 recv_error:
540	kfree(rpl_context);
541	spin_lock_irqsave(&rdma->req_lock, flags);
542	if (err != -EINTR && rdma->state < P9_RDMA_CLOSING) {
543		rdma->state = P9_RDMA_CLOSING;
544		spin_unlock_irqrestore(&rdma->req_lock, flags);
545		rdma_disconnect(rdma->cm_id);
546	} else
547		spin_unlock_irqrestore(&rdma->req_lock, flags);
548	return err;
549}
550
551static void rdma_close(struct p9_client *client)
552{
553	struct p9_trans_rdma *rdma;
554
555	if (!client)
556		return;
557
558	rdma = client->trans;
559	if (!rdma)
560		return;
561
562	client->status = Disconnected;
563	rdma_disconnect(rdma->cm_id);
564	rdma_destroy_trans(rdma);
565}
566
567/**
568 * alloc_rdma - Allocate and initialize the rdma transport structure
569 * @opts: Mount options structure
570 */
571static struct p9_trans_rdma *alloc_rdma(struct p9_rdma_opts *opts)
572{
573	struct p9_trans_rdma *rdma;
574
575	rdma = kzalloc(sizeof(struct p9_trans_rdma), GFP_KERNEL);
576	if (!rdma)
577		return NULL;
578
579	rdma->port = opts->port;
580	rdma->privport = opts->privport;
581	rdma->sq_depth = opts->sq_depth;
582	rdma->rq_depth = opts->rq_depth;
583	rdma->timeout = opts->timeout;
584	spin_lock_init(&rdma->req_lock);
585	init_completion(&rdma->cm_done);
586	sema_init(&rdma->sq_sem, rdma->sq_depth);
587	sema_init(&rdma->rq_sem, rdma->rq_depth);
588	atomic_set(&rdma->excess_rc, 0);
589
590	return rdma;
591}
592
593static int rdma_cancel(struct p9_client *client, struct p9_req_t *req)
594{
595	/* Nothing to do here.
596	 * We will take care of it (if we have to) in rdma_cancelled()
597	 */
598	return 1;
599}
600
601/* A request has been fully flushed without a reply.
602 * That means we have posted one buffer in excess.
603 */
604static int rdma_cancelled(struct p9_client *client, struct p9_req_t *req)
605{
606	struct p9_trans_rdma *rdma = client->trans;
607	atomic_inc(&rdma->excess_rc);
608	return 0;
609}
610
611static int p9_rdma_bind_privport(struct p9_trans_rdma *rdma)
612{
613	struct sockaddr_in cl = {
614		.sin_family = AF_INET,
615		.sin_addr.s_addr = htonl(INADDR_ANY),
616	};
617	int port, err = -EINVAL;
618
619	for (port = P9_DEF_MAX_RESVPORT; port >= P9_DEF_MIN_RESVPORT; port--) {
620		cl.sin_port = htons((ushort)port);
621		err = rdma_bind_addr(rdma->cm_id, (struct sockaddr *)&cl);
622		if (err != -EADDRINUSE)
623			break;
624	}
625	return err;
626}
627
628/**
629 * rdma_create_trans - Transport method for creating a transport instance
630 * @client: client instance
631 * @addr: IP address string
632 * @args: Mount options string
633 */
634static int
635rdma_create_trans(struct p9_client *client, const char *addr, char *args)
636{
637	int err;
638	struct p9_rdma_opts opts;
639	struct p9_trans_rdma *rdma;
640	struct rdma_conn_param conn_param;
641	struct ib_qp_init_attr qp_attr;
642
643	if (addr == NULL)
644		return -EINVAL;
645
646	/* Parse the transport specific mount options */
647	err = parse_opts(args, &opts);
648	if (err < 0)
649		return err;
650
651	/* Create and initialize the RDMA transport structure */
652	rdma = alloc_rdma(&opts);
653	if (!rdma)
654		return -ENOMEM;
655
656	/* Create the RDMA CM ID */
657	rdma->cm_id = rdma_create_id(&init_net, p9_cm_event_handler, client,
658				     RDMA_PS_TCP, IB_QPT_RC);
659	if (IS_ERR(rdma->cm_id))
660		goto error;
661
662	/* Associate the client with the transport */
663	client->trans = rdma;
664
665	/* Bind to a privileged port if we need to */
666	if (opts.privport) {
667		err = p9_rdma_bind_privport(rdma);
668		if (err < 0) {
669			pr_err("%s (%d): problem binding to privport: %d\n",
670			       __func__, task_pid_nr(current), -err);
671			goto error;
672		}
673	}
674
675	/* Resolve the server's address */
676	rdma->addr.sin_family = AF_INET;
677	rdma->addr.sin_addr.s_addr = in_aton(addr);
678	rdma->addr.sin_port = htons(opts.port);
679	err = rdma_resolve_addr(rdma->cm_id, NULL,
680				(struct sockaddr *)&rdma->addr,
681				rdma->timeout);
682	if (err)
683		goto error;
684	err = wait_for_completion_interruptible(&rdma->cm_done);
685	if (err || (rdma->state != P9_RDMA_ADDR_RESOLVED))
686		goto error;
687
688	/* Resolve the route to the server */
689	err = rdma_resolve_route(rdma->cm_id, rdma->timeout);
690	if (err)
691		goto error;
692	err = wait_for_completion_interruptible(&rdma->cm_done);
693	if (err || (rdma->state != P9_RDMA_ROUTE_RESOLVED))
694		goto error;
695
696	/* Create the Completion Queue */
697	rdma->cq = ib_alloc_cq_any(rdma->cm_id->device, client,
698				   opts.sq_depth + opts.rq_depth + 1,
699				   IB_POLL_SOFTIRQ);
700	if (IS_ERR(rdma->cq))
701		goto error;
702
703	/* Create the Protection Domain */
704	rdma->pd = ib_alloc_pd(rdma->cm_id->device, 0);
705	if (IS_ERR(rdma->pd))
706		goto error;
707
708	/* Create the Queue Pair */
709	memset(&qp_attr, 0, sizeof qp_attr);
710	qp_attr.event_handler = qp_event_handler;
711	qp_attr.qp_context = client;
712	qp_attr.cap.max_send_wr = opts.sq_depth;
713	qp_attr.cap.max_recv_wr = opts.rq_depth;
714	qp_attr.cap.max_send_sge = P9_RDMA_SEND_SGE;
715	qp_attr.cap.max_recv_sge = P9_RDMA_RECV_SGE;
716	qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
717	qp_attr.qp_type = IB_QPT_RC;
718	qp_attr.send_cq = rdma->cq;
719	qp_attr.recv_cq = rdma->cq;
720	err = rdma_create_qp(rdma->cm_id, rdma->pd, &qp_attr);
721	if (err)
722		goto error;
723	rdma->qp = rdma->cm_id->qp;
724
725	/* Request a connection */
726	memset(&conn_param, 0, sizeof(conn_param));
727	conn_param.private_data = NULL;
728	conn_param.private_data_len = 0;
729	conn_param.responder_resources = P9_RDMA_IRD;
730	conn_param.initiator_depth = P9_RDMA_ORD;
731	err = rdma_connect(rdma->cm_id, &conn_param);
732	if (err)
733		goto error;
734	err = wait_for_completion_interruptible(&rdma->cm_done);
735	if (err || (rdma->state != P9_RDMA_CONNECTED))
736		goto error;
737
738	client->status = Connected;
739
740	return 0;
741
742error:
743	rdma_destroy_trans(rdma);
744	return -ENOTCONN;
745}
746
747static struct p9_trans_module p9_rdma_trans = {
748	.name = "rdma",
749	.maxsize = P9_RDMA_MAXSIZE,
750	.pooled_rbuffers = true,
751	.def = 0,
752	.owner = THIS_MODULE,
753	.create = rdma_create_trans,
754	.close = rdma_close,
755	.request = rdma_request,
756	.cancel = rdma_cancel,
757	.cancelled = rdma_cancelled,
758	.show_options = p9_rdma_show_options,
759};
760
761/**
762 * p9_trans_rdma_init - Register the 9P RDMA transport driver
763 */
764static int __init p9_trans_rdma_init(void)
765{
766	v9fs_register_trans(&p9_rdma_trans);
767	return 0;
768}
769
770static void __exit p9_trans_rdma_exit(void)
771{
772	v9fs_unregister_trans(&p9_rdma_trans);
773}
774
775module_init(p9_trans_rdma_init);
776module_exit(p9_trans_rdma_exit);
777MODULE_ALIAS_9P("rdma");
778
779MODULE_AUTHOR("Tom Tucker <tom@opengridcomputing.com>");
780MODULE_DESCRIPTION("RDMA Transport for 9P");
781MODULE_LICENSE("Dual BSD/GPL");
782