xref: /linux/net/9p/trans_rdma.c (revision b61104e7a6349bd2c2b3e2fb3260d87f15eda8f4) 
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/fs_context.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_RDMA_SEND_SGE	4
36 #define P9_RDMA_RECV_SGE	4
37 #define P9_RDMA_IRD		0
38 #define P9_RDMA_ORD		0
39 #define P9_RDMA_MAXSIZE		(1024*1024)	/* 1MB */
40 
41 /**
42  * struct p9_trans_rdma - RDMA transport instance
43  *
44  * @state: tracks the transport state machine for connection setup and tear down
45  * @cm_id: The RDMA CM ID
46  * @pd: Protection Domain pointer
47  * @qp: Queue Pair pointer
48  * @cq: Completion Queue pointer
49  * @timeout: Number of uSecs to wait for connection management events
50  * @privport: Whether a privileged port may be used
51  * @port: The port to use
52  * @sq_depth: The depth of the Send Queue
53  * @sq_sem: Semaphore for the SQ
54  * @rq_depth: The depth of the Receive Queue.
55  * @rq_sem: Semaphore for the RQ
56  * @excess_rc : Amount of posted Receive Contexts without a pending request.
57  *		See rdma_request()
58  * @addr: The remote peer's address
59  * @req_lock: Protects the active request list
60  * @cm_done: Completion event for connection management tracking
61  */
62 struct p9_trans_rdma {
63 	enum {
64 		P9_RDMA_INIT,
65 		P9_RDMA_ADDR_RESOLVED,
66 		P9_RDMA_ROUTE_RESOLVED,
67 		P9_RDMA_CONNECTED,
68 		P9_RDMA_FLUSHING,
69 		P9_RDMA_CLOSING,
70 		P9_RDMA_CLOSED,
71 	} state;
72 	struct rdma_cm_id *cm_id;
73 	struct ib_pd *pd;
74 	struct ib_qp *qp;
75 	struct ib_cq *cq;
76 	long timeout;
77 	bool privport;
78 	u16 port;
79 	int sq_depth;
80 	struct semaphore sq_sem;
81 	int rq_depth;
82 	struct semaphore rq_sem;
83 	atomic_t excess_rc;
84 	struct sockaddr_in addr;
85 	spinlock_t req_lock;
86 
87 	struct completion cm_done;
88 };
89 
90 struct p9_rdma_req;
91 
92 /**
93  * struct p9_rdma_context - Keeps track of in-process WR
94  *
95  * @cqe: completion queue entry
96  * @busa: Bus address to unmap when the WR completes
97  * @req: Keeps track of requests (send)
98  * @rc: Keepts track of replies (receive)
99  */
100 struct p9_rdma_context {
101 	struct ib_cqe cqe;
102 	dma_addr_t busa;
103 	union {
104 		struct p9_req_t *req;
105 		struct p9_fcall rc;
106 	};
107 };
108 
109 static int p9_rdma_show_options(struct seq_file *m, struct p9_client *clnt)
110 {
111 	struct p9_trans_rdma *rdma = clnt->trans;
112 
113 	if (rdma->port != P9_RDMA_PORT)
114 		seq_printf(m, ",port=%u", rdma->port);
115 	if (rdma->sq_depth != P9_RDMA_SQ_DEPTH)
116 		seq_printf(m, ",sq=%u", rdma->sq_depth);
117 	if (rdma->rq_depth != P9_RDMA_RQ_DEPTH)
118 		seq_printf(m, ",rq=%u", rdma->rq_depth);
119 	if (rdma->timeout != P9_RDMA_TIMEOUT)
120 		seq_printf(m, ",timeout=%lu", rdma->timeout);
121 	if (rdma->privport)
122 		seq_puts(m, ",privport");
123 	return 0;
124 }
125 
126 static int
127 p9_cm_event_handler(struct rdma_cm_id *id, struct rdma_cm_event *event)
128 {
129 	struct p9_client *c = id->context;
130 	struct p9_trans_rdma *rdma = c->trans;
131 	switch (event->event) {
132 	case RDMA_CM_EVENT_ADDR_RESOLVED:
133 		BUG_ON(rdma->state != P9_RDMA_INIT);
134 		rdma->state = P9_RDMA_ADDR_RESOLVED;
135 		break;
136 
137 	case RDMA_CM_EVENT_ROUTE_RESOLVED:
138 		BUG_ON(rdma->state != P9_RDMA_ADDR_RESOLVED);
139 		rdma->state = P9_RDMA_ROUTE_RESOLVED;
140 		break;
141 
142 	case RDMA_CM_EVENT_ESTABLISHED:
143 		BUG_ON(rdma->state != P9_RDMA_ROUTE_RESOLVED);
144 		rdma->state = P9_RDMA_CONNECTED;
145 		break;
146 
147 	case RDMA_CM_EVENT_DISCONNECTED:
148 		if (rdma)
149 			rdma->state = P9_RDMA_CLOSED;
150 		c->status = Disconnected;
151 		break;
152 
153 	case RDMA_CM_EVENT_TIMEWAIT_EXIT:
154 		break;
155 
156 	case RDMA_CM_EVENT_ADDR_CHANGE:
157 	case RDMA_CM_EVENT_ROUTE_ERROR:
158 	case RDMA_CM_EVENT_DEVICE_REMOVAL:
159 	case RDMA_CM_EVENT_MULTICAST_JOIN:
160 	case RDMA_CM_EVENT_MULTICAST_ERROR:
161 	case RDMA_CM_EVENT_REJECTED:
162 	case RDMA_CM_EVENT_CONNECT_REQUEST:
163 	case RDMA_CM_EVENT_CONNECT_RESPONSE:
164 	case RDMA_CM_EVENT_CONNECT_ERROR:
165 	case RDMA_CM_EVENT_ADDR_ERROR:
166 	case RDMA_CM_EVENT_UNREACHABLE:
167 		c->status = Disconnected;
168 		rdma_disconnect(rdma->cm_id);
169 		break;
170 	default:
171 		BUG();
172 	}
173 	complete(&rdma->cm_done);
174 	return 0;
175 }
176 
177 static void
178 recv_done(struct ib_cq *cq, struct ib_wc *wc)
179 {
180 	struct p9_client *client = cq->cq_context;
181 	struct p9_trans_rdma *rdma = client->trans;
182 	struct p9_rdma_context *c =
183 		container_of(wc->wr_cqe, struct p9_rdma_context, cqe);
184 	struct p9_req_t *req;
185 	int err = 0;
186 	int16_t tag;
187 
188 	req = NULL;
189 	ib_dma_unmap_single(rdma->cm_id->device, c->busa, client->msize,
190 							 DMA_FROM_DEVICE);
191 
192 	if (wc->status != IB_WC_SUCCESS)
193 		goto err_out;
194 
195 	c->rc.size = wc->byte_len;
196 	err = p9_parse_header(&c->rc, NULL, NULL, &tag, 1);
197 	if (err)
198 		goto err_out;
199 
200 	req = p9_tag_lookup(client, tag);
201 	if (!req)
202 		goto err_out;
203 
204 	/* Check that we have not yet received a reply for this request.
205 	 */
206 	if (unlikely(req->rc.sdata)) {
207 		pr_err("Duplicate reply for request %d", tag);
208 		goto err_out;
209 	}
210 
211 	req->rc.size = c->rc.size;
212 	req->rc.sdata = c->rc.sdata;
213 	p9_client_cb(client, req, REQ_STATUS_RCVD);
214 
215  out:
216 	up(&rdma->rq_sem);
217 	kfree(c);
218 	return;
219 
220  err_out:
221 	p9_debug(P9_DEBUG_ERROR, "req %p err %d status %d\n",
222 			req, err, wc->status);
223 	rdma->state = P9_RDMA_FLUSHING;
224 	client->status = Disconnected;
225 	goto out;
226 }
227 
228 static void
229 send_done(struct ib_cq *cq, struct ib_wc *wc)
230 {
231 	struct p9_client *client = cq->cq_context;
232 	struct p9_trans_rdma *rdma = client->trans;
233 	struct p9_rdma_context *c =
234 		container_of(wc->wr_cqe, struct p9_rdma_context, cqe);
235 
236 	ib_dma_unmap_single(rdma->cm_id->device,
237 			    c->busa, c->req->tc.size,
238 			    DMA_TO_DEVICE);
239 	up(&rdma->sq_sem);
240 	p9_req_put(client, c->req);
241 	kfree(c);
242 }
243 
244 static void qp_event_handler(struct ib_event *event, void *context)
245 {
246 	p9_debug(P9_DEBUG_ERROR, "QP event %d context %p\n",
247 		 event->event, context);
248 }
249 
250 static void rdma_destroy_trans(struct p9_trans_rdma *rdma)
251 {
252 	if (!rdma)
253 		return;
254 
255 	if (rdma->qp && !IS_ERR(rdma->qp))
256 		ib_destroy_qp(rdma->qp);
257 
258 	if (rdma->pd && !IS_ERR(rdma->pd))
259 		ib_dealloc_pd(rdma->pd);
260 
261 	if (rdma->cq && !IS_ERR(rdma->cq))
262 		ib_free_cq(rdma->cq);
263 
264 	if (rdma->cm_id && !IS_ERR(rdma->cm_id))
265 		rdma_destroy_id(rdma->cm_id);
266 
267 	kfree(rdma);
268 }
269 
270 static int
271 post_recv(struct p9_client *client, struct p9_rdma_context *c)
272 {
273 	struct p9_trans_rdma *rdma = client->trans;
274 	struct ib_recv_wr wr;
275 	struct ib_sge sge;
276 	int ret;
277 
278 	c->busa = ib_dma_map_single(rdma->cm_id->device,
279 				    c->rc.sdata, client->msize,
280 				    DMA_FROM_DEVICE);
281 	if (ib_dma_mapping_error(rdma->cm_id->device, c->busa))
282 		goto error;
283 
284 	c->cqe.done = recv_done;
285 
286 	sge.addr = c->busa;
287 	sge.length = client->msize;
288 	sge.lkey = rdma->pd->local_dma_lkey;
289 
290 	wr.next = NULL;
291 	wr.wr_cqe = &c->cqe;
292 	wr.sg_list = &sge;
293 	wr.num_sge = 1;
294 
295 	ret = ib_post_recv(rdma->qp, &wr, NULL);
296 	if (ret)
297 		ib_dma_unmap_single(rdma->cm_id->device, c->busa,
298 				    client->msize, DMA_FROM_DEVICE);
299 	return ret;
300 
301  error:
302 	p9_debug(P9_DEBUG_ERROR, "EIO\n");
303 	return -EIO;
304 }
305 
306 static int rdma_request(struct p9_client *client, struct p9_req_t *req)
307 {
308 	struct p9_trans_rdma *rdma = client->trans;
309 	struct ib_send_wr wr;
310 	struct ib_sge sge;
311 	int err = 0;
312 	unsigned long flags;
313 	struct p9_rdma_context *c = NULL;
314 	struct p9_rdma_context *rpl_context = NULL;
315 
316 	/* When an error occurs between posting the recv and the send,
317 	 * there will be a receive context posted without a pending request.
318 	 * Since there is no way to "un-post" it, we remember it and skip
319 	 * post_recv() for the next request.
320 	 * So here,
321 	 * see if we are this `next request' and need to absorb an excess rc.
322 	 * If yes, then drop and free our own, and do not recv_post().
323 	 **/
324 	if (unlikely(atomic_read(&rdma->excess_rc) > 0)) {
325 		if ((atomic_sub_return(1, &rdma->excess_rc) >= 0)) {
326 			/* Got one! */
327 			p9_fcall_fini(&req->rc);
328 			req->rc.sdata = NULL;
329 			goto dont_need_post_recv;
330 		} else {
331 			/* We raced and lost. */
332 			atomic_inc(&rdma->excess_rc);
333 		}
334 	}
335 
336 	/* Allocate an fcall for the reply */
337 	rpl_context = kmalloc(sizeof *rpl_context, GFP_NOFS);
338 	if (!rpl_context) {
339 		err = -ENOMEM;
340 		goto recv_error;
341 	}
342 	rpl_context->rc.sdata = req->rc.sdata;
343 
344 	/*
345 	 * Post a receive buffer for this request. We need to ensure
346 	 * there is a reply buffer available for every outstanding
347 	 * request. A flushed request can result in no reply for an
348 	 * outstanding request, so we must keep a count to avoid
349 	 * overflowing the RQ.
350 	 */
351 	if (down_interruptible(&rdma->rq_sem)) {
352 		err = -EINTR;
353 		goto recv_error;
354 	}
355 
356 	err = post_recv(client, rpl_context);
357 	if (err) {
358 		p9_debug(P9_DEBUG_ERROR, "POST RECV failed: %d\n", err);
359 		goto recv_error;
360 	}
361 	/* remove posted receive buffer from request structure */
362 	req->rc.sdata = NULL;
363 
364 dont_need_post_recv:
365 	/* Post the request */
366 	c = kmalloc(sizeof *c, GFP_NOFS);
367 	if (!c) {
368 		err = -ENOMEM;
369 		goto send_error;
370 	}
371 	c->req = req;
372 
373 	c->busa = ib_dma_map_single(rdma->cm_id->device,
374 				    c->req->tc.sdata, c->req->tc.size,
375 				    DMA_TO_DEVICE);
376 	if (ib_dma_mapping_error(rdma->cm_id->device, c->busa)) {
377 		err = -EIO;
378 		goto send_error;
379 	}
380 
381 	c->cqe.done = send_done;
382 
383 	sge.addr = c->busa;
384 	sge.length = c->req->tc.size;
385 	sge.lkey = rdma->pd->local_dma_lkey;
386 
387 	wr.next = NULL;
388 	wr.wr_cqe = &c->cqe;
389 	wr.opcode = IB_WR_SEND;
390 	wr.send_flags = IB_SEND_SIGNALED;
391 	wr.sg_list = &sge;
392 	wr.num_sge = 1;
393 
394 	if (down_interruptible(&rdma->sq_sem)) {
395 		err = -EINTR;
396 		goto dma_unmap;
397 	}
398 
399 	/* Mark request as `sent' *before* we actually send it,
400 	 * because doing if after could erase the REQ_STATUS_RCVD
401 	 * status in case of a very fast reply.
402 	 */
403 	WRITE_ONCE(req->status, REQ_STATUS_SENT);
404 	err = ib_post_send(rdma->qp, &wr, NULL);
405 	if (err)
406 		goto dma_unmap;
407 
408 	/* Success */
409 	return 0;
410 
411 dma_unmap:
412 	ib_dma_unmap_single(rdma->cm_id->device, c->busa,
413 			    c->req->tc.size, DMA_TO_DEVICE);
414  /* Handle errors that happened during or while preparing the send: */
415  send_error:
416 	WRITE_ONCE(req->status, REQ_STATUS_ERROR);
417 	kfree(c);
418 	p9_debug(P9_DEBUG_ERROR, "Error %d in rdma_request()\n", err);
419 
420 	/* Ach.
421 	 *  We did recv_post(), but not send. We have one recv_post in excess.
422 	 */
423 	atomic_inc(&rdma->excess_rc);
424 	return err;
425 
426  /* Handle errors that happened during or while preparing post_recv(): */
427  recv_error:
428 	kfree(rpl_context);
429 	spin_lock_irqsave(&rdma->req_lock, flags);
430 	if (err != -EINTR && rdma->state < P9_RDMA_CLOSING) {
431 		rdma->state = P9_RDMA_CLOSING;
432 		spin_unlock_irqrestore(&rdma->req_lock, flags);
433 		rdma_disconnect(rdma->cm_id);
434 	} else
435 		spin_unlock_irqrestore(&rdma->req_lock, flags);
436 	return err;
437 }
438 
439 static void rdma_close(struct p9_client *client)
440 {
441 	struct p9_trans_rdma *rdma;
442 
443 	if (!client)
444 		return;
445 
446 	rdma = client->trans;
447 	if (!rdma)
448 		return;
449 
450 	client->status = Disconnected;
451 	rdma_disconnect(rdma->cm_id);
452 	rdma_destroy_trans(rdma);
453 }
454 
455 /**
456  * alloc_rdma - Allocate and initialize the rdma transport structure
457  * @opts: Mount options structure
458  */
459 static struct p9_trans_rdma *alloc_rdma(struct p9_rdma_opts *opts)
460 {
461 	struct p9_trans_rdma *rdma;
462 
463 	rdma = kzalloc(sizeof(struct p9_trans_rdma), GFP_KERNEL);
464 	if (!rdma)
465 		return NULL;
466 
467 	rdma->port = opts->port;
468 	rdma->privport = opts->privport;
469 	rdma->sq_depth = opts->sq_depth;
470 	rdma->rq_depth = opts->rq_depth;
471 	rdma->timeout = opts->timeout;
472 	spin_lock_init(&rdma->req_lock);
473 	init_completion(&rdma->cm_done);
474 	sema_init(&rdma->sq_sem, rdma->sq_depth);
475 	sema_init(&rdma->rq_sem, rdma->rq_depth);
476 	atomic_set(&rdma->excess_rc, 0);
477 
478 	return rdma;
479 }
480 
481 static int rdma_cancel(struct p9_client *client, struct p9_req_t *req)
482 {
483 	/* Nothing to do here.
484 	 * We will take care of it (if we have to) in rdma_cancelled()
485 	 */
486 	return 1;
487 }
488 
489 /* A request has been fully flushed without a reply.
490  * That means we have posted one buffer in excess.
491  */
492 static int rdma_cancelled(struct p9_client *client, struct p9_req_t *req)
493 {
494 	struct p9_trans_rdma *rdma = client->trans;
495 	atomic_inc(&rdma->excess_rc);
496 	return 0;
497 }
498 
499 static int p9_rdma_bind_privport(struct p9_trans_rdma *rdma)
500 {
501 	struct sockaddr_in cl = {
502 		.sin_family = AF_INET,
503 		.sin_addr.s_addr = htonl(INADDR_ANY),
504 	};
505 	int port, err = -EINVAL;
506 
507 	for (port = P9_DEF_MAX_RESVPORT; port >= P9_DEF_MIN_RESVPORT; port--) {
508 		cl.sin_port = htons((ushort)port);
509 		err = rdma_bind_addr(rdma->cm_id, (struct sockaddr *)&cl);
510 		if (err != -EADDRINUSE)
511 			break;
512 	}
513 	return err;
514 }
515 
516 /**
517  * rdma_create_trans - Transport method for creating a transport instance
518  * @client: client instance
519  * @fc: The filesystem context
520  */
521 static int
522 rdma_create_trans(struct p9_client *client, struct fs_context *fc)
523 {
524 	const char *addr = fc->source;
525 	struct v9fs_context *ctx = fc->fs_private;
526 	struct p9_rdma_opts opts = ctx->rdma_opts;
527 	int err;
528 	struct p9_trans_rdma *rdma;
529 	struct rdma_conn_param conn_param;
530 	struct ib_qp_init_attr qp_attr;
531 
532 	if (addr == NULL)
533 		return -EINVAL;
534 
535 	/* options are already parsed, in the fs context */
536 	opts = ctx->rdma_opts;
537 
538 	/* Create and initialize the RDMA transport structure */
539 	rdma = alloc_rdma(&opts);
540 	if (!rdma)
541 		return -ENOMEM;
542 
543 	/* Create the RDMA CM ID */
544 	rdma->cm_id = rdma_create_id(&init_net, p9_cm_event_handler, client,
545 				     RDMA_PS_TCP, IB_QPT_RC);
546 	if (IS_ERR(rdma->cm_id))
547 		goto error;
548 
549 	/* Associate the client with the transport */
550 	client->trans = rdma;
551 
552 	/* Bind to a privileged port if we need to */
553 	if (opts.privport) {
554 		err = p9_rdma_bind_privport(rdma);
555 		if (err < 0) {
556 			pr_err("%s (%d): problem binding to privport: %d\n",
557 			       __func__, task_pid_nr(current), -err);
558 			goto error;
559 		}
560 	}
561 
562 	/* Resolve the server's address */
563 	rdma->addr.sin_family = AF_INET;
564 	rdma->addr.sin_addr.s_addr = in_aton(addr);
565 	rdma->addr.sin_port = htons(opts.port);
566 	err = rdma_resolve_addr(rdma->cm_id, NULL,
567 				(struct sockaddr *)&rdma->addr,
568 				rdma->timeout);
569 	if (err)
570 		goto error;
571 	err = wait_for_completion_interruptible(&rdma->cm_done);
572 	if (err || (rdma->state != P9_RDMA_ADDR_RESOLVED))
573 		goto error;
574 
575 	/* Resolve the route to the server */
576 	err = rdma_resolve_route(rdma->cm_id, rdma->timeout);
577 	if (err)
578 		goto error;
579 	err = wait_for_completion_interruptible(&rdma->cm_done);
580 	if (err || (rdma->state != P9_RDMA_ROUTE_RESOLVED))
581 		goto error;
582 
583 	/* Create the Completion Queue */
584 	rdma->cq = ib_alloc_cq_any(rdma->cm_id->device, client,
585 				   opts.sq_depth + opts.rq_depth + 1,
586 				   IB_POLL_SOFTIRQ);
587 	if (IS_ERR(rdma->cq))
588 		goto error;
589 
590 	/* Create the Protection Domain */
591 	rdma->pd = ib_alloc_pd(rdma->cm_id->device, 0);
592 	if (IS_ERR(rdma->pd))
593 		goto error;
594 
595 	/* Create the Queue Pair */
596 	memset(&qp_attr, 0, sizeof qp_attr);
597 	qp_attr.event_handler = qp_event_handler;
598 	qp_attr.qp_context = client;
599 	qp_attr.cap.max_send_wr = opts.sq_depth;
600 	qp_attr.cap.max_recv_wr = opts.rq_depth;
601 	qp_attr.cap.max_send_sge = P9_RDMA_SEND_SGE;
602 	qp_attr.cap.max_recv_sge = P9_RDMA_RECV_SGE;
603 	qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
604 	qp_attr.qp_type = IB_QPT_RC;
605 	qp_attr.send_cq = rdma->cq;
606 	qp_attr.recv_cq = rdma->cq;
607 	err = rdma_create_qp(rdma->cm_id, rdma->pd, &qp_attr);
608 	if (err)
609 		goto error;
610 	rdma->qp = rdma->cm_id->qp;
611 
612 	/* Request a connection */
613 	memset(&conn_param, 0, sizeof(conn_param));
614 	conn_param.private_data = NULL;
615 	conn_param.private_data_len = 0;
616 	conn_param.responder_resources = P9_RDMA_IRD;
617 	conn_param.initiator_depth = P9_RDMA_ORD;
618 	err = rdma_connect(rdma->cm_id, &conn_param);
619 	if (err)
620 		goto error;
621 	err = wait_for_completion_interruptible(&rdma->cm_done);
622 	if (err || (rdma->state != P9_RDMA_CONNECTED))
623 		goto error;
624 
625 	client->status = Connected;
626 
627 	return 0;
628 
629 error:
630 	rdma_destroy_trans(rdma);
631 	return -ENOTCONN;
632 }
633 
634 static struct p9_trans_module p9_rdma_trans = {
635 	.name = "rdma",
636 	.maxsize = P9_RDMA_MAXSIZE,
637 	.pooled_rbuffers = true,
638 	.def = false,
639 	.supports_vmalloc = false,
640 	.owner = THIS_MODULE,
641 	.create = rdma_create_trans,
642 	.close = rdma_close,
643 	.request = rdma_request,
644 	.cancel = rdma_cancel,
645 	.cancelled = rdma_cancelled,
646 	.show_options = p9_rdma_show_options,
647 };
648 
649 /**
650  * p9_trans_rdma_init - Register the 9P RDMA transport driver
651  */
652 static int __init p9_trans_rdma_init(void)
653 {
654 	v9fs_register_trans(&p9_rdma_trans);
655 	return 0;
656 }
657 
658 static void __exit p9_trans_rdma_exit(void)
659 {
660 	v9fs_unregister_trans(&p9_rdma_trans);
661 }
662 
663 module_init(p9_trans_rdma_init);
664 module_exit(p9_trans_rdma_exit);
665 MODULE_ALIAS_9P("rdma");
666 
667 MODULE_AUTHOR("Tom Tucker <tom@opengridcomputing.com>");
668 MODULE_DESCRIPTION("RDMA Transport for 9P");
669 MODULE_LICENSE("Dual BSD/GPL");
670