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v5.14.15
  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 */
 69struct 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
 97struct p9_rdma_req;
 98
 99/**
100 * struct p9_rdma_context - Keeps track of in-process WR
101 *
102 * @cqe: completion queue entry
103 * @busa: Bus address to unmap when the WR completes
104 * @req: Keeps track of requests (send)
105 * @rc: Keepts track of replies (receive)
106 */
 
107struct p9_rdma_context {
108	struct ib_cqe cqe;
109	dma_addr_t busa;
110	union {
111		struct p9_req_t *req;
112		struct p9_fcall rc;
113	};
114};
115
116/**
117 * struct p9_rdma_opts - Collection of mount options
118 * @port: port of connection
119 * @privport: Whether a privileged port may be used
120 * @sq_depth: The requested depth of the SQ. This really doesn't need
121 * to be any deeper than the number of threads used in the client
122 * @rq_depth: The depth of the RQ. Should be greater than or equal to SQ depth
123 * @timeout: Time to wait in msecs for CM events
124 */
125struct p9_rdma_opts {
126	short port;
127	bool privport;
128	int sq_depth;
129	int rq_depth;
130	long timeout;
131};
132
133/*
134 * Option Parsing (code inspired by NFS code)
135 */
136enum {
137	/* Options that take integer arguments */
138	Opt_port, Opt_rq_depth, Opt_sq_depth, Opt_timeout,
139	/* Options that take no argument */
140	Opt_privport,
141	Opt_err,
142};
143
144static match_table_t tokens = {
145	{Opt_port, "port=%u"},
146	{Opt_sq_depth, "sq=%u"},
147	{Opt_rq_depth, "rq=%u"},
148	{Opt_timeout, "timeout=%u"},
149	{Opt_privport, "privport"},
150	{Opt_err, NULL},
151};
152
153static int p9_rdma_show_options(struct seq_file *m, struct p9_client *clnt)
154{
155	struct p9_trans_rdma *rdma = clnt->trans;
156
157	if (rdma->port != P9_PORT)
158		seq_printf(m, ",port=%u", rdma->port);
159	if (rdma->sq_depth != P9_RDMA_SQ_DEPTH)
160		seq_printf(m, ",sq=%u", rdma->sq_depth);
161	if (rdma->rq_depth != P9_RDMA_RQ_DEPTH)
162		seq_printf(m, ",rq=%u", rdma->rq_depth);
163	if (rdma->timeout != P9_RDMA_TIMEOUT)
164		seq_printf(m, ",timeout=%lu", rdma->timeout);
165	if (rdma->privport)
166		seq_puts(m, ",privport");
167	return 0;
168}
169
170/**
171 * parse_opts - parse mount options into rdma options structure
172 * @params: options string passed from mount
173 * @opts: rdma transport-specific structure to parse options into
174 *
175 * Returns 0 upon success, -ERRNO upon failure
176 */
177static int parse_opts(char *params, struct p9_rdma_opts *opts)
178{
179	char *p;
180	substring_t args[MAX_OPT_ARGS];
181	int option;
182	char *options, *tmp_options;
183
184	opts->port = P9_PORT;
185	opts->sq_depth = P9_RDMA_SQ_DEPTH;
186	opts->rq_depth = P9_RDMA_RQ_DEPTH;
187	opts->timeout = P9_RDMA_TIMEOUT;
188	opts->privport = false;
189
190	if (!params)
191		return 0;
192
193	tmp_options = kstrdup(params, GFP_KERNEL);
194	if (!tmp_options) {
195		p9_debug(P9_DEBUG_ERROR,
196			 "failed to allocate copy of option string\n");
197		return -ENOMEM;
198	}
199	options = tmp_options;
200
201	while ((p = strsep(&options, ",")) != NULL) {
202		int token;
203		int r;
204		if (!*p)
205			continue;
206		token = match_token(p, tokens, args);
207		if ((token != Opt_err) && (token != Opt_privport)) {
208			r = match_int(&args[0], &option);
209			if (r < 0) {
210				p9_debug(P9_DEBUG_ERROR,
211					 "integer field, but no integer?\n");
212				continue;
213			}
214		}
215		switch (token) {
216		case Opt_port:
217			opts->port = option;
218			break;
219		case Opt_sq_depth:
220			opts->sq_depth = option;
221			break;
222		case Opt_rq_depth:
223			opts->rq_depth = option;
224			break;
225		case Opt_timeout:
226			opts->timeout = option;
227			break;
228		case Opt_privport:
229			opts->privport = true;
230			break;
231		default:
232			continue;
233		}
234	}
235	/* RQ must be at least as large as the SQ */
236	opts->rq_depth = max(opts->rq_depth, opts->sq_depth);
237	kfree(tmp_options);
238	return 0;
239}
240
241static int
242p9_cm_event_handler(struct rdma_cm_id *id, struct rdma_cm_event *event)
243{
244	struct p9_client *c = id->context;
245	struct p9_trans_rdma *rdma = c->trans;
246	switch (event->event) {
247	case RDMA_CM_EVENT_ADDR_RESOLVED:
248		BUG_ON(rdma->state != P9_RDMA_INIT);
249		rdma->state = P9_RDMA_ADDR_RESOLVED;
250		break;
251
252	case RDMA_CM_EVENT_ROUTE_RESOLVED:
253		BUG_ON(rdma->state != P9_RDMA_ADDR_RESOLVED);
254		rdma->state = P9_RDMA_ROUTE_RESOLVED;
255		break;
256
257	case RDMA_CM_EVENT_ESTABLISHED:
258		BUG_ON(rdma->state != P9_RDMA_ROUTE_RESOLVED);
259		rdma->state = P9_RDMA_CONNECTED;
260		break;
261
262	case RDMA_CM_EVENT_DISCONNECTED:
263		if (rdma)
264			rdma->state = P9_RDMA_CLOSED;
265		c->status = Disconnected;
 
266		break;
267
268	case RDMA_CM_EVENT_TIMEWAIT_EXIT:
269		break;
270
271	case RDMA_CM_EVENT_ADDR_CHANGE:
272	case RDMA_CM_EVENT_ROUTE_ERROR:
273	case RDMA_CM_EVENT_DEVICE_REMOVAL:
274	case RDMA_CM_EVENT_MULTICAST_JOIN:
275	case RDMA_CM_EVENT_MULTICAST_ERROR:
276	case RDMA_CM_EVENT_REJECTED:
277	case RDMA_CM_EVENT_CONNECT_REQUEST:
278	case RDMA_CM_EVENT_CONNECT_RESPONSE:
279	case RDMA_CM_EVENT_CONNECT_ERROR:
280	case RDMA_CM_EVENT_ADDR_ERROR:
281	case RDMA_CM_EVENT_UNREACHABLE:
282		c->status = Disconnected;
283		rdma_disconnect(rdma->cm_id);
284		break;
285	default:
286		BUG();
287	}
288	complete(&rdma->cm_done);
289	return 0;
290}
291
292static void
293recv_done(struct ib_cq *cq, struct ib_wc *wc)
 
294{
295	struct p9_client *client = cq->cq_context;
296	struct p9_trans_rdma *rdma = client->trans;
297	struct p9_rdma_context *c =
298		container_of(wc->wr_cqe, struct p9_rdma_context, cqe);
299	struct p9_req_t *req;
300	int err = 0;
301	int16_t tag;
302
303	req = NULL;
304	ib_dma_unmap_single(rdma->cm_id->device, c->busa, client->msize,
305							 DMA_FROM_DEVICE);
306
307	if (wc->status != IB_WC_SUCCESS)
308		goto err_out;
309
310	c->rc.size = wc->byte_len;
311	err = p9_parse_header(&c->rc, NULL, NULL, &tag, 1);
312	if (err)
313		goto err_out;
314
315	req = p9_tag_lookup(client, tag);
316	if (!req)
317		goto err_out;
318
319	/* Check that we have not yet received a reply for this request.
320	 */
321	if (unlikely(req->rc.sdata)) {
322		pr_err("Duplicate reply for request %d", tag);
323		goto err_out;
324	}
325
326	req->rc.size = c->rc.size;
327	req->rc.sdata = c->rc.sdata;
328	p9_client_cb(client, req, REQ_STATUS_RCVD);
329
330 out:
331	up(&rdma->rq_sem);
332	kfree(c);
333	return;
334
335 err_out:
336	p9_debug(P9_DEBUG_ERROR, "req %p err %d status %d\n",
337			req, err, wc->status);
338	rdma->state = P9_RDMA_FLUSHING;
339	client->status = Disconnected;
340	goto out;
341}
342
343static void
344send_done(struct ib_cq *cq, struct ib_wc *wc)
 
345{
346	struct p9_client *client = cq->cq_context;
347	struct p9_trans_rdma *rdma = client->trans;
348	struct p9_rdma_context *c =
349		container_of(wc->wr_cqe, struct p9_rdma_context, cqe);
350
351	ib_dma_unmap_single(rdma->cm_id->device,
352			    c->busa, c->req->tc.size,
353			    DMA_TO_DEVICE);
354	up(&rdma->sq_sem);
355	p9_req_put(c->req);
356	kfree(c);
357}
358
359static void qp_event_handler(struct ib_event *event, void *context)
360{
361	p9_debug(P9_DEBUG_ERROR, "QP event %d context %p\n",
362		 event->event, context);
363}
364
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
365static void rdma_destroy_trans(struct p9_trans_rdma *rdma)
366{
367	if (!rdma)
368		return;
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_free_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
385static int
386post_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;
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	c->cqe.done = recv_done;
399
400	sge.addr = c->busa;
401	sge.length = client->msize;
402	sge.lkey = rdma->pd->local_dma_lkey;
403
404	wr.next = NULL;
405	wr.wr_cqe = &c->cqe;
 
406	wr.sg_list = &sge;
407	wr.num_sge = 1;
408	return ib_post_recv(rdma->qp, &wr, NULL);
409
410 error:
411	p9_debug(P9_DEBUG_ERROR, "EIO\n");
412	return -EIO;
413}
414
415static int rdma_request(struct p9_client *client, struct p9_req_t *req)
416{
417	struct p9_trans_rdma *rdma = client->trans;
418	struct ib_send_wr wr;
419	struct ib_sge sge;
420	int err = 0;
421	unsigned long flags;
422	struct p9_rdma_context *c = NULL;
423	struct p9_rdma_context *rpl_context = NULL;
424
425	/* When an error occurs between posting the recv and the send,
426	 * there will be a receive context posted without a pending request.
427	 * Since there is no way to "un-post" it, we remember it and skip
428	 * post_recv() for the next request.
429	 * So here,
430	 * see if we are this `next request' and need to absorb an excess rc.
431	 * If yes, then drop and free our own, and do not recv_post().
432	 **/
433	if (unlikely(atomic_read(&rdma->excess_rc) > 0)) {
434		if ((atomic_sub_return(1, &rdma->excess_rc) >= 0)) {
435			/* Got one! */
436			p9_fcall_fini(&req->rc);
437			req->rc.sdata = NULL;
438			goto dont_need_post_recv;
439		} else {
440			/* We raced and lost. */
441			atomic_inc(&rdma->excess_rc);
442		}
443	}
444
445	/* Allocate an fcall for the reply */
446	rpl_context = kmalloc(sizeof *rpl_context, GFP_NOFS);
447	if (!rpl_context) {
448		err = -ENOMEM;
449		goto recv_error;
450	}
451	rpl_context->rc.sdata = req->rc.sdata;
452
453	/*
454	 * Post a receive buffer for this request. We need to ensure
455	 * there is a reply buffer available for every outstanding
456	 * request. A flushed request can result in no reply for an
457	 * outstanding request, so we must keep a count to avoid
458	 * overflowing the RQ.
459	 */
460	if (down_interruptible(&rdma->rq_sem)) {
461		err = -EINTR;
462		goto recv_error;
463	}
464
465	err = post_recv(client, rpl_context);
466	if (err) {
467		p9_debug(P9_DEBUG_ERROR, "POST RECV failed: %d\n", err);
468		goto recv_error;
469	}
470	/* remove posted receive buffer from request structure */
471	req->rc.sdata = NULL;
472
473dont_need_post_recv:
474	/* Post the request */
475	c = kmalloc(sizeof *c, GFP_NOFS);
476	if (!c) {
477		err = -ENOMEM;
478		goto send_error;
479	}
480	c->req = req;
481
482	c->busa = ib_dma_map_single(rdma->cm_id->device,
483				    c->req->tc.sdata, c->req->tc.size,
484				    DMA_TO_DEVICE);
485	if (ib_dma_mapping_error(rdma->cm_id->device, c->busa)) {
486		err = -EIO;
487		goto send_error;
488	}
489
490	c->cqe.done = send_done;
491
492	sge.addr = c->busa;
493	sge.length = c->req->tc.size;
494	sge.lkey = rdma->pd->local_dma_lkey;
495
496	wr.next = NULL;
497	wr.wr_cqe = &c->cqe;
 
498	wr.opcode = IB_WR_SEND;
499	wr.send_flags = IB_SEND_SIGNALED;
500	wr.sg_list = &sge;
501	wr.num_sge = 1;
502
503	if (down_interruptible(&rdma->sq_sem)) {
504		err = -EINTR;
505		goto send_error;
506	}
507
508	/* Mark request as `sent' *before* we actually send it,
509	 * because doing if after could erase the REQ_STATUS_RCVD
510	 * status in case of a very fast reply.
511	 */
512	req->status = REQ_STATUS_SENT;
513	err = ib_post_send(rdma->qp, &wr, NULL);
514	if (err)
515		goto send_error;
516
517	/* Success */
518	return 0;
519
520 /* Handle errors that happened during or while preparing the send: */
521 send_error:
522	req->status = REQ_STATUS_ERROR;
523	kfree(c);
524	p9_debug(P9_DEBUG_ERROR, "Error %d in rdma_request()\n", err);
525
526	/* Ach.
527	 *  We did recv_post(), but not send. We have one recv_post in excess.
528	 */
529	atomic_inc(&rdma->excess_rc);
530	return err;
531
532 /* Handle errors that happened during or while preparing post_recv(): */
533 recv_error:
534	kfree(rpl_context);
535	spin_lock_irqsave(&rdma->req_lock, flags);
536	if (err != -EINTR && rdma->state < P9_RDMA_CLOSING) {
537		rdma->state = P9_RDMA_CLOSING;
538		spin_unlock_irqrestore(&rdma->req_lock, flags);
539		rdma_disconnect(rdma->cm_id);
540	} else
541		spin_unlock_irqrestore(&rdma->req_lock, flags);
542	return err;
543}
544
545static void rdma_close(struct p9_client *client)
546{
547	struct p9_trans_rdma *rdma;
548
549	if (!client)
550		return;
551
552	rdma = client->trans;
553	if (!rdma)
554		return;
555
556	client->status = Disconnected;
557	rdma_disconnect(rdma->cm_id);
558	rdma_destroy_trans(rdma);
559}
560
561/**
562 * alloc_rdma - Allocate and initialize the rdma transport structure
563 * @opts: Mount options structure
564 */
565static struct p9_trans_rdma *alloc_rdma(struct p9_rdma_opts *opts)
566{
567	struct p9_trans_rdma *rdma;
568
569	rdma = kzalloc(sizeof(struct p9_trans_rdma), GFP_KERNEL);
570	if (!rdma)
571		return NULL;
572
573	rdma->port = opts->port;
574	rdma->privport = opts->privport;
575	rdma->sq_depth = opts->sq_depth;
576	rdma->rq_depth = opts->rq_depth;
577	rdma->timeout = opts->timeout;
578	spin_lock_init(&rdma->req_lock);
579	init_completion(&rdma->cm_done);
580	sema_init(&rdma->sq_sem, rdma->sq_depth);
581	sema_init(&rdma->rq_sem, rdma->rq_depth);
582	atomic_set(&rdma->excess_rc, 0);
583
584	return rdma;
585}
586
587static int rdma_cancel(struct p9_client *client, struct p9_req_t *req)
588{
589	/* Nothing to do here.
590	 * We will take care of it (if we have to) in rdma_cancelled()
591	 */
592	return 1;
593}
594
595/* A request has been fully flushed without a reply.
596 * That means we have posted one buffer in excess.
597 */
598static int rdma_cancelled(struct p9_client *client, struct p9_req_t *req)
599{
600	struct p9_trans_rdma *rdma = client->trans;
601	atomic_inc(&rdma->excess_rc);
602	return 0;
603}
604
605static int p9_rdma_bind_privport(struct p9_trans_rdma *rdma)
606{
607	struct sockaddr_in cl = {
608		.sin_family = AF_INET,
609		.sin_addr.s_addr = htonl(INADDR_ANY),
610	};
611	int port, err = -EINVAL;
612
613	for (port = P9_DEF_MAX_RESVPORT; port >= P9_DEF_MIN_RESVPORT; port--) {
614		cl.sin_port = htons((ushort)port);
615		err = rdma_bind_addr(rdma->cm_id, (struct sockaddr *)&cl);
616		if (err != -EADDRINUSE)
617			break;
618	}
619	return err;
620}
621
622/**
623 * rdma_create_trans - Transport method for creating a transport instance
624 * @client: client instance
625 * @addr: IP address string
626 * @args: Mount options string
627 */
628static int
629rdma_create_trans(struct p9_client *client, const char *addr, char *args)
630{
631	int err;
632	struct p9_rdma_opts opts;
633	struct p9_trans_rdma *rdma;
634	struct rdma_conn_param conn_param;
635	struct ib_qp_init_attr qp_attr;
636
637	if (addr == NULL)
638		return -EINVAL;
639
640	/* Parse the transport specific mount options */
641	err = parse_opts(args, &opts);
642	if (err < 0)
643		return err;
644
645	/* Create and initialize the RDMA transport structure */
646	rdma = alloc_rdma(&opts);
647	if (!rdma)
648		return -ENOMEM;
649
650	/* Create the RDMA CM ID */
651	rdma->cm_id = rdma_create_id(&init_net, p9_cm_event_handler, client,
652				     RDMA_PS_TCP, IB_QPT_RC);
653	if (IS_ERR(rdma->cm_id))
654		goto error;
655
656	/* Associate the client with the transport */
657	client->trans = rdma;
658
659	/* Bind to a privileged port if we need to */
660	if (opts.privport) {
661		err = p9_rdma_bind_privport(rdma);
662		if (err < 0) {
663			pr_err("%s (%d): problem binding to privport: %d\n",
664			       __func__, task_pid_nr(current), -err);
665			goto error;
666		}
667	}
668
669	/* Resolve the server's address */
670	rdma->addr.sin_family = AF_INET;
671	rdma->addr.sin_addr.s_addr = in_aton(addr);
672	rdma->addr.sin_port = htons(opts.port);
673	err = rdma_resolve_addr(rdma->cm_id, NULL,
674				(struct sockaddr *)&rdma->addr,
675				rdma->timeout);
676	if (err)
677		goto error;
678	err = wait_for_completion_interruptible(&rdma->cm_done);
679	if (err || (rdma->state != P9_RDMA_ADDR_RESOLVED))
680		goto error;
681
682	/* Resolve the route to the server */
683	err = rdma_resolve_route(rdma->cm_id, rdma->timeout);
684	if (err)
685		goto error;
686	err = wait_for_completion_interruptible(&rdma->cm_done);
687	if (err || (rdma->state != P9_RDMA_ROUTE_RESOLVED))
688		goto error;
689
 
 
 
 
 
690	/* Create the Completion Queue */
691	rdma->cq = ib_alloc_cq_any(rdma->cm_id->device, client,
692				   opts.sq_depth + opts.rq_depth + 1,
693				   IB_POLL_SOFTIRQ);
694	if (IS_ERR(rdma->cq))
695		goto error;
 
696
697	/* Create the Protection Domain */
698	rdma->pd = ib_alloc_pd(rdma->cm_id->device, 0);
699	if (IS_ERR(rdma->pd))
700		goto error;
701
 
 
 
 
 
 
 
 
 
 
 
702	/* Create the Queue Pair */
703	memset(&qp_attr, 0, sizeof qp_attr);
704	qp_attr.event_handler = qp_event_handler;
705	qp_attr.qp_context = client;
706	qp_attr.cap.max_send_wr = opts.sq_depth;
707	qp_attr.cap.max_recv_wr = opts.rq_depth;
708	qp_attr.cap.max_send_sge = P9_RDMA_SEND_SGE;
709	qp_attr.cap.max_recv_sge = P9_RDMA_RECV_SGE;
710	qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
711	qp_attr.qp_type = IB_QPT_RC;
712	qp_attr.send_cq = rdma->cq;
713	qp_attr.recv_cq = rdma->cq;
714	err = rdma_create_qp(rdma->cm_id, rdma->pd, &qp_attr);
715	if (err)
716		goto error;
717	rdma->qp = rdma->cm_id->qp;
718
719	/* Request a connection */
720	memset(&conn_param, 0, sizeof(conn_param));
721	conn_param.private_data = NULL;
722	conn_param.private_data_len = 0;
723	conn_param.responder_resources = P9_RDMA_IRD;
724	conn_param.initiator_depth = P9_RDMA_ORD;
725	err = rdma_connect(rdma->cm_id, &conn_param);
726	if (err)
727		goto error;
728	err = wait_for_completion_interruptible(&rdma->cm_done);
729	if (err || (rdma->state != P9_RDMA_CONNECTED))
730		goto error;
731
732	client->status = Connected;
733
734	return 0;
735
736error:
737	rdma_destroy_trans(rdma);
738	return -ENOTCONN;
739}
740
741static struct p9_trans_module p9_rdma_trans = {
742	.name = "rdma",
743	.maxsize = P9_RDMA_MAXSIZE,
744	.def = 0,
745	.owner = THIS_MODULE,
746	.create = rdma_create_trans,
747	.close = rdma_close,
748	.request = rdma_request,
749	.cancel = rdma_cancel,
750	.cancelled = rdma_cancelled,
751	.show_options = p9_rdma_show_options,
752};
753
754/**
755 * p9_trans_rdma_init - Register the 9P RDMA transport driver
756 */
757static int __init p9_trans_rdma_init(void)
758{
759	v9fs_register_trans(&p9_rdma_trans);
760	return 0;
761}
762
763static void __exit p9_trans_rdma_exit(void)
764{
765	v9fs_unregister_trans(&p9_rdma_trans);
766}
767
768module_init(p9_trans_rdma_init);
769module_exit(p9_trans_rdma_exit);
770
771MODULE_AUTHOR("Tom Tucker <tom@opengridcomputing.com>");
772MODULE_DESCRIPTION("RDMA Transport for 9P");
773MODULE_LICENSE("Dual BSD/GPL");
v3.15
 
  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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 30
 31#include <linux/in.h>
 32#include <linux/module.h>
 33#include <linux/net.h>
 34#include <linux/ipv6.h>
 35#include <linux/kthread.h>
 36#include <linux/errno.h>
 37#include <linux/kernel.h>
 38#include <linux/un.h>
 39#include <linux/uaccess.h>
 40#include <linux/inet.h>
 41#include <linux/idr.h>
 42#include <linux/file.h>
 43#include <linux/parser.h>
 44#include <linux/semaphore.h>
 45#include <linux/slab.h>
 
 46#include <net/9p/9p.h>
 47#include <net/9p/client.h>
 48#include <net/9p/transport.h>
 49#include <rdma/ib_verbs.h>
 50#include <rdma/rdma_cm.h>
 51
 52#define P9_PORT			5640
 53#define P9_RDMA_SQ_DEPTH	32
 54#define P9_RDMA_RQ_DEPTH	32
 55#define P9_RDMA_SEND_SGE	4
 56#define P9_RDMA_RECV_SGE	4
 57#define P9_RDMA_IRD		0
 58#define P9_RDMA_ORD		0
 59#define P9_RDMA_TIMEOUT		30000		/* 30 seconds */
 60#define P9_RDMA_MAXSIZE		(1024*1024)	/* 1MB */
 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_sem: Semaphore for the RQ
 77 * @excess_rc : Amount of posted Receive Contexts without a pending request.
 78 *		See rdma_request()
 79 * @addr: The remote peer's address
 80 * @req_lock: Protects the active request list
 81 * @cm_done: Completion event for connection management tracking
 82 */
 83struct p9_trans_rdma {
 84	enum {
 85		P9_RDMA_INIT,
 86		P9_RDMA_ADDR_RESOLVED,
 87		P9_RDMA_ROUTE_RESOLVED,
 88		P9_RDMA_CONNECTED,
 89		P9_RDMA_FLUSHING,
 90		P9_RDMA_CLOSING,
 91		P9_RDMA_CLOSED,
 92	} state;
 93	struct rdma_cm_id *cm_id;
 94	struct ib_pd *pd;
 95	struct ib_qp *qp;
 96	struct ib_cq *cq;
 97	struct ib_mr *dma_mr;
 98	u32 lkey;
 99	long timeout;
 
 
100	int sq_depth;
101	struct semaphore sq_sem;
102	int rq_depth;
103	struct semaphore rq_sem;
104	atomic_t excess_rc;
105	struct sockaddr_in addr;
106	spinlock_t req_lock;
107
108	struct completion cm_done;
109};
110
 
 
111/**
112 * p9_rdma_context - Keeps track of in-process WR
113 *
114 * @wc_op: The original WR op for when the CQE completes in error.
115 * @busa: Bus address to unmap when the WR completes
116 * @req: Keeps track of requests (send)
117 * @rc: Keepts track of replies (receive)
118 */
119struct p9_rdma_req;
120struct p9_rdma_context {
121	enum ib_wc_opcode wc_op;
122	dma_addr_t busa;
123	union {
124		struct p9_req_t *req;
125		struct p9_fcall *rc;
126	};
127};
128
129/**
130 * p9_rdma_opts - Collection of mount options
131 * @port: port of connection
 
132 * @sq_depth: The requested depth of the SQ. This really doesn't need
133 * to be any deeper than the number of threads used in the client
134 * @rq_depth: The depth of the RQ. Should be greater than or equal to SQ depth
135 * @timeout: Time to wait in msecs for CM events
136 */
137struct p9_rdma_opts {
138	short port;
 
139	int sq_depth;
140	int rq_depth;
141	long timeout;
142};
143
144/*
145 * Option Parsing (code inspired by NFS code)
146 */
147enum {
148	/* Options that take integer arguments */
149	Opt_port, Opt_rq_depth, Opt_sq_depth, Opt_timeout, Opt_err,
 
 
 
150};
151
152static match_table_t tokens = {
153	{Opt_port, "port=%u"},
154	{Opt_sq_depth, "sq=%u"},
155	{Opt_rq_depth, "rq=%u"},
156	{Opt_timeout, "timeout=%u"},
 
157	{Opt_err, NULL},
158};
159
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
160/**
161 * parse_opts - parse mount options into rdma options structure
162 * @params: options string passed from mount
163 * @opts: rdma transport-specific structure to parse options into
164 *
165 * Returns 0 upon success, -ERRNO upon failure
166 */
167static int parse_opts(char *params, struct p9_rdma_opts *opts)
168{
169	char *p;
170	substring_t args[MAX_OPT_ARGS];
171	int option;
172	char *options, *tmp_options;
173
174	opts->port = P9_PORT;
175	opts->sq_depth = P9_RDMA_SQ_DEPTH;
176	opts->rq_depth = P9_RDMA_RQ_DEPTH;
177	opts->timeout = P9_RDMA_TIMEOUT;
 
178
179	if (!params)
180		return 0;
181
182	tmp_options = kstrdup(params, GFP_KERNEL);
183	if (!tmp_options) {
184		p9_debug(P9_DEBUG_ERROR,
185			 "failed to allocate copy of option string\n");
186		return -ENOMEM;
187	}
188	options = tmp_options;
189
190	while ((p = strsep(&options, ",")) != NULL) {
191		int token;
192		int r;
193		if (!*p)
194			continue;
195		token = match_token(p, tokens, args);
196		if (token == Opt_err)
197			continue;
198		r = match_int(&args[0], &option);
199		if (r < 0) {
200			p9_debug(P9_DEBUG_ERROR,
201				 "integer field, but no integer?\n");
202			continue;
203		}
204		switch (token) {
205		case Opt_port:
206			opts->port = option;
207			break;
208		case Opt_sq_depth:
209			opts->sq_depth = option;
210			break;
211		case Opt_rq_depth:
212			opts->rq_depth = option;
213			break;
214		case Opt_timeout:
215			opts->timeout = option;
216			break;
 
 
 
217		default:
218			continue;
219		}
220	}
221	/* RQ must be at least as large as the SQ */
222	opts->rq_depth = max(opts->rq_depth, opts->sq_depth);
223	kfree(tmp_options);
224	return 0;
225}
226
227static int
228p9_cm_event_handler(struct rdma_cm_id *id, struct rdma_cm_event *event)
229{
230	struct p9_client *c = id->context;
231	struct p9_trans_rdma *rdma = c->trans;
232	switch (event->event) {
233	case RDMA_CM_EVENT_ADDR_RESOLVED:
234		BUG_ON(rdma->state != P9_RDMA_INIT);
235		rdma->state = P9_RDMA_ADDR_RESOLVED;
236		break;
237
238	case RDMA_CM_EVENT_ROUTE_RESOLVED:
239		BUG_ON(rdma->state != P9_RDMA_ADDR_RESOLVED);
240		rdma->state = P9_RDMA_ROUTE_RESOLVED;
241		break;
242
243	case RDMA_CM_EVENT_ESTABLISHED:
244		BUG_ON(rdma->state != P9_RDMA_ROUTE_RESOLVED);
245		rdma->state = P9_RDMA_CONNECTED;
246		break;
247
248	case RDMA_CM_EVENT_DISCONNECTED:
249		if (rdma)
250			rdma->state = P9_RDMA_CLOSED;
251		if (c)
252			c->status = Disconnected;
253		break;
254
255	case RDMA_CM_EVENT_TIMEWAIT_EXIT:
256		break;
257
258	case RDMA_CM_EVENT_ADDR_CHANGE:
259	case RDMA_CM_EVENT_ROUTE_ERROR:
260	case RDMA_CM_EVENT_DEVICE_REMOVAL:
261	case RDMA_CM_EVENT_MULTICAST_JOIN:
262	case RDMA_CM_EVENT_MULTICAST_ERROR:
263	case RDMA_CM_EVENT_REJECTED:
264	case RDMA_CM_EVENT_CONNECT_REQUEST:
265	case RDMA_CM_EVENT_CONNECT_RESPONSE:
266	case RDMA_CM_EVENT_CONNECT_ERROR:
267	case RDMA_CM_EVENT_ADDR_ERROR:
268	case RDMA_CM_EVENT_UNREACHABLE:
269		c->status = Disconnected;
270		rdma_disconnect(rdma->cm_id);
271		break;
272	default:
273		BUG();
274	}
275	complete(&rdma->cm_done);
276	return 0;
277}
278
279static void
280handle_recv(struct p9_client *client, struct p9_trans_rdma *rdma,
281	    struct p9_rdma_context *c, enum ib_wc_status status, u32 byte_len)
282{
 
 
 
 
283	struct p9_req_t *req;
284	int err = 0;
285	int16_t tag;
286
287	req = NULL;
288	ib_dma_unmap_single(rdma->cm_id->device, c->busa, client->msize,
289							 DMA_FROM_DEVICE);
290
291	if (status != IB_WC_SUCCESS)
292		goto err_out;
293
294	err = p9_parse_header(c->rc, NULL, NULL, &tag, 1);
 
295	if (err)
296		goto err_out;
297
298	req = p9_tag_lookup(client, tag);
299	if (!req)
300		goto err_out;
301
302	/* Check that we have not yet received a reply for this request.
303	 */
304	if (unlikely(req->rc)) {
305		pr_err("Duplicate reply for request %d", tag);
306		goto err_out;
307	}
308
309	req->rc = c->rc;
 
310	p9_client_cb(client, req, REQ_STATUS_RCVD);
311
 
 
 
312	return;
313
314 err_out:
315	p9_debug(P9_DEBUG_ERROR, "req %p err %d status %d\n", req, err, status);
 
316	rdma->state = P9_RDMA_FLUSHING;
317	client->status = Disconnected;
 
318}
319
320static void
321handle_send(struct p9_client *client, struct p9_trans_rdma *rdma,
322	    struct p9_rdma_context *c, enum ib_wc_status status, u32 byte_len)
323{
 
 
 
 
 
324	ib_dma_unmap_single(rdma->cm_id->device,
325			    c->busa, c->req->tc->size,
326			    DMA_TO_DEVICE);
 
 
 
327}
328
329static void qp_event_handler(struct ib_event *event, void *context)
330{
331	p9_debug(P9_DEBUG_ERROR, "QP event %d context %p\n",
332		 event->event, context);
333}
334
335static void cq_comp_handler(struct ib_cq *cq, void *cq_context)
336{
337	struct p9_client *client = cq_context;
338	struct p9_trans_rdma *rdma = client->trans;
339	int ret;
340	struct ib_wc wc;
341
342	ib_req_notify_cq(rdma->cq, IB_CQ_NEXT_COMP);
343	while ((ret = ib_poll_cq(cq, 1, &wc)) > 0) {
344		struct p9_rdma_context *c = (void *) (unsigned long) wc.wr_id;
345
346		switch (c->wc_op) {
347		case IB_WC_RECV:
348			handle_recv(client, rdma, c, wc.status, wc.byte_len);
349			up(&rdma->rq_sem);
350			break;
351
352		case IB_WC_SEND:
353			handle_send(client, rdma, c, wc.status, wc.byte_len);
354			up(&rdma->sq_sem);
355			break;
356
357		default:
358			pr_err("unexpected completion type, c->wc_op=%d, wc.opcode=%d, status=%d\n",
359			       c->wc_op, wc.opcode, wc.status);
360			break;
361		}
362		kfree(c);
363	}
364}
365
366static void cq_event_handler(struct ib_event *e, void *v)
367{
368	p9_debug(P9_DEBUG_ERROR, "CQ event %d context %p\n", e->event, v);
369}
370
371static void rdma_destroy_trans(struct p9_trans_rdma *rdma)
372{
373	if (!rdma)
374		return;
375
376	if (rdma->dma_mr && !IS_ERR(rdma->dma_mr))
377		ib_dereg_mr(rdma->dma_mr);
378
379	if (rdma->qp && !IS_ERR(rdma->qp))
380		ib_destroy_qp(rdma->qp);
381
382	if (rdma->pd && !IS_ERR(rdma->pd))
383		ib_dealloc_pd(rdma->pd);
384
385	if (rdma->cq && !IS_ERR(rdma->cq))
386		ib_destroy_cq(rdma->cq);
387
388	if (rdma->cm_id && !IS_ERR(rdma->cm_id))
389		rdma_destroy_id(rdma->cm_id);
390
391	kfree(rdma);
392}
393
394static int
395post_recv(struct p9_client *client, struct p9_rdma_context *c)
396{
397	struct p9_trans_rdma *rdma = client->trans;
398	struct ib_recv_wr wr, *bad_wr;
399	struct ib_sge sge;
400
401	c->busa = ib_dma_map_single(rdma->cm_id->device,
402				    c->rc->sdata, client->msize,
403				    DMA_FROM_DEVICE);
404	if (ib_dma_mapping_error(rdma->cm_id->device, c->busa))
405		goto error;
406
 
 
407	sge.addr = c->busa;
408	sge.length = client->msize;
409	sge.lkey = rdma->lkey;
410
411	wr.next = NULL;
412	c->wc_op = IB_WC_RECV;
413	wr.wr_id = (unsigned long) c;
414	wr.sg_list = &sge;
415	wr.num_sge = 1;
416	return ib_post_recv(rdma->qp, &wr, &bad_wr);
417
418 error:
419	p9_debug(P9_DEBUG_ERROR, "EIO\n");
420	return -EIO;
421}
422
423static int rdma_request(struct p9_client *client, struct p9_req_t *req)
424{
425	struct p9_trans_rdma *rdma = client->trans;
426	struct ib_send_wr wr, *bad_wr;
427	struct ib_sge sge;
428	int err = 0;
429	unsigned long flags;
430	struct p9_rdma_context *c = NULL;
431	struct p9_rdma_context *rpl_context = NULL;
432
433	/* When an error occurs between posting the recv and the send,
434	 * there will be a receive context posted without a pending request.
435	 * Since there is no way to "un-post" it, we remember it and skip
436	 * post_recv() for the next request.
437	 * So here,
438	 * see if we are this `next request' and need to absorb an excess rc.
439	 * If yes, then drop and free our own, and do not recv_post().
440	 **/
441	if (unlikely(atomic_read(&rdma->excess_rc) > 0)) {
442		if ((atomic_sub_return(1, &rdma->excess_rc) >= 0)) {
443			/* Got one ! */
444			kfree(req->rc);
445			req->rc = NULL;
446			goto dont_need_post_recv;
447		} else {
448			/* We raced and lost. */
449			atomic_inc(&rdma->excess_rc);
450		}
451	}
452
453	/* Allocate an fcall for the reply */
454	rpl_context = kmalloc(sizeof *rpl_context, GFP_NOFS);
455	if (!rpl_context) {
456		err = -ENOMEM;
457		goto recv_error;
458	}
459	rpl_context->rc = req->rc;
460
461	/*
462	 * Post a receive buffer for this request. We need to ensure
463	 * there is a reply buffer available for every outstanding
464	 * request. A flushed request can result in no reply for an
465	 * outstanding request, so we must keep a count to avoid
466	 * overflowing the RQ.
467	 */
468	if (down_interruptible(&rdma->rq_sem)) {
469		err = -EINTR;
470		goto recv_error;
471	}
472
473	err = post_recv(client, rpl_context);
474	if (err) {
475		p9_debug(P9_DEBUG_FCALL, "POST RECV failed\n");
476		goto recv_error;
477	}
478	/* remove posted receive buffer from request structure */
479	req->rc = NULL;
480
481dont_need_post_recv:
482	/* Post the request */
483	c = kmalloc(sizeof *c, GFP_NOFS);
484	if (!c) {
485		err = -ENOMEM;
486		goto send_error;
487	}
488	c->req = req;
489
490	c->busa = ib_dma_map_single(rdma->cm_id->device,
491				    c->req->tc->sdata, c->req->tc->size,
492				    DMA_TO_DEVICE);
493	if (ib_dma_mapping_error(rdma->cm_id->device, c->busa)) {
494		err = -EIO;
495		goto send_error;
496	}
497
 
 
498	sge.addr = c->busa;
499	sge.length = c->req->tc->size;
500	sge.lkey = rdma->lkey;
501
502	wr.next = NULL;
503	c->wc_op = IB_WC_SEND;
504	wr.wr_id = (unsigned long) c;
505	wr.opcode = IB_WR_SEND;
506	wr.send_flags = IB_SEND_SIGNALED;
507	wr.sg_list = &sge;
508	wr.num_sge = 1;
509
510	if (down_interruptible(&rdma->sq_sem)) {
511		err = -EINTR;
512		goto send_error;
513	}
514
515	/* Mark request as `sent' *before* we actually send it,
516	 * because doing if after could erase the REQ_STATUS_RCVD
517	 * status in case of a very fast reply.
518	 */
519	req->status = REQ_STATUS_SENT;
520	err = ib_post_send(rdma->qp, &wr, &bad_wr);
521	if (err)
522		goto send_error;
523
524	/* Success */
525	return 0;
526
527 /* Handle errors that happened during or while preparing the send: */
528 send_error:
529	req->status = REQ_STATUS_ERROR;
530	kfree(c);
531	p9_debug(P9_DEBUG_ERROR, "Error %d in rdma_request()\n", err);
532
533	/* Ach.
534	 *  We did recv_post(), but not send. We have one recv_post in excess.
535	 */
536	atomic_inc(&rdma->excess_rc);
537	return err;
538
539 /* Handle errors that happened during or while preparing post_recv(): */
540 recv_error:
541	kfree(rpl_context);
542	spin_lock_irqsave(&rdma->req_lock, flags);
543	if (rdma->state < P9_RDMA_CLOSING) {
544		rdma->state = P9_RDMA_CLOSING;
545		spin_unlock_irqrestore(&rdma->req_lock, flags);
546		rdma_disconnect(rdma->cm_id);
547	} else
548		spin_unlock_irqrestore(&rdma->req_lock, flags);
549	return err;
550}
551
552static void rdma_close(struct p9_client *client)
553{
554	struct p9_trans_rdma *rdma;
555
556	if (!client)
557		return;
558
559	rdma = client->trans;
560	if (!rdma)
561		return;
562
563	client->status = Disconnected;
564	rdma_disconnect(rdma->cm_id);
565	rdma_destroy_trans(rdma);
566}
567
568/**
569 * alloc_rdma - Allocate and initialize the rdma transport structure
570 * @opts: Mount options structure
571 */
572static struct p9_trans_rdma *alloc_rdma(struct p9_rdma_opts *opts)
573{
574	struct p9_trans_rdma *rdma;
575
576	rdma = kzalloc(sizeof(struct p9_trans_rdma), GFP_KERNEL);
577	if (!rdma)
578		return NULL;
579
 
 
580	rdma->sq_depth = opts->sq_depth;
581	rdma->rq_depth = opts->rq_depth;
582	rdma->timeout = opts->timeout;
583	spin_lock_init(&rdma->req_lock);
584	init_completion(&rdma->cm_done);
585	sema_init(&rdma->sq_sem, rdma->sq_depth);
586	sema_init(&rdma->rq_sem, rdma->rq_depth);
587	atomic_set(&rdma->excess_rc, 0);
588
589	return rdma;
590}
591
592static int rdma_cancel(struct p9_client *client, struct p9_req_t *req)
593{
594	/* Nothing to do here.
595	 * We will take care of it (if we have to) in rdma_cancelled()
596	 */
597	return 1;
598}
599
600/* A request has been fully flushed without a reply.
601 * That means we have posted one buffer in excess.
602 */
603static int rdma_cancelled(struct p9_client *client, struct p9_req_t *req)
604{
605	struct p9_trans_rdma *rdma = client->trans;
606	atomic_inc(&rdma->excess_rc);
607	return 0;
608}
609
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
610/**
611 * trans_create_rdma - Transport method for creating atransport instance
612 * @client: client instance
613 * @addr: IP address string
614 * @args: Mount options string
615 */
616static int
617rdma_create_trans(struct p9_client *client, const char *addr, char *args)
618{
619	int err;
620	struct p9_rdma_opts opts;
621	struct p9_trans_rdma *rdma;
622	struct rdma_conn_param conn_param;
623	struct ib_qp_init_attr qp_attr;
624	struct ib_device_attr devattr;
 
 
625
626	/* Parse the transport specific mount options */
627	err = parse_opts(args, &opts);
628	if (err < 0)
629		return err;
630
631	/* Create and initialize the RDMA transport structure */
632	rdma = alloc_rdma(&opts);
633	if (!rdma)
634		return -ENOMEM;
635
636	/* Create the RDMA CM ID */
637	rdma->cm_id = rdma_create_id(p9_cm_event_handler, client, RDMA_PS_TCP,
638				     IB_QPT_RC);
639	if (IS_ERR(rdma->cm_id))
640		goto error;
641
642	/* Associate the client with the transport */
643	client->trans = rdma;
644
 
 
 
 
 
 
 
 
 
 
645	/* Resolve the server's address */
646	rdma->addr.sin_family = AF_INET;
647	rdma->addr.sin_addr.s_addr = in_aton(addr);
648	rdma->addr.sin_port = htons(opts.port);
649	err = rdma_resolve_addr(rdma->cm_id, NULL,
650				(struct sockaddr *)&rdma->addr,
651				rdma->timeout);
652	if (err)
653		goto error;
654	err = wait_for_completion_interruptible(&rdma->cm_done);
655	if (err || (rdma->state != P9_RDMA_ADDR_RESOLVED))
656		goto error;
657
658	/* Resolve the route to the server */
659	err = rdma_resolve_route(rdma->cm_id, rdma->timeout);
660	if (err)
661		goto error;
662	err = wait_for_completion_interruptible(&rdma->cm_done);
663	if (err || (rdma->state != P9_RDMA_ROUTE_RESOLVED))
664		goto error;
665
666	/* Query the device attributes */
667	err = ib_query_device(rdma->cm_id->device, &devattr);
668	if (err)
669		goto error;
670
671	/* Create the Completion Queue */
672	rdma->cq = ib_create_cq(rdma->cm_id->device, cq_comp_handler,
673				cq_event_handler, client,
674				opts.sq_depth + opts.rq_depth + 1, 0);
675	if (IS_ERR(rdma->cq))
676		goto error;
677	ib_req_notify_cq(rdma->cq, IB_CQ_NEXT_COMP);
678
679	/* Create the Protection Domain */
680	rdma->pd = ib_alloc_pd(rdma->cm_id->device);
681	if (IS_ERR(rdma->pd))
682		goto error;
683
684	/* Cache the DMA lkey in the transport */
685	rdma->dma_mr = NULL;
686	if (devattr.device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY)
687		rdma->lkey = rdma->cm_id->device->local_dma_lkey;
688	else {
689		rdma->dma_mr = ib_get_dma_mr(rdma->pd, IB_ACCESS_LOCAL_WRITE);
690		if (IS_ERR(rdma->dma_mr))
691			goto error;
692		rdma->lkey = rdma->dma_mr->lkey;
693	}
694
695	/* Create the Queue Pair */
696	memset(&qp_attr, 0, sizeof qp_attr);
697	qp_attr.event_handler = qp_event_handler;
698	qp_attr.qp_context = client;
699	qp_attr.cap.max_send_wr = opts.sq_depth;
700	qp_attr.cap.max_recv_wr = opts.rq_depth;
701	qp_attr.cap.max_send_sge = P9_RDMA_SEND_SGE;
702	qp_attr.cap.max_recv_sge = P9_RDMA_RECV_SGE;
703	qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
704	qp_attr.qp_type = IB_QPT_RC;
705	qp_attr.send_cq = rdma->cq;
706	qp_attr.recv_cq = rdma->cq;
707	err = rdma_create_qp(rdma->cm_id, rdma->pd, &qp_attr);
708	if (err)
709		goto error;
710	rdma->qp = rdma->cm_id->qp;
711
712	/* Request a connection */
713	memset(&conn_param, 0, sizeof(conn_param));
714	conn_param.private_data = NULL;
715	conn_param.private_data_len = 0;
716	conn_param.responder_resources = P9_RDMA_IRD;
717	conn_param.initiator_depth = P9_RDMA_ORD;
718	err = rdma_connect(rdma->cm_id, &conn_param);
719	if (err)
720		goto error;
721	err = wait_for_completion_interruptible(&rdma->cm_done);
722	if (err || (rdma->state != P9_RDMA_CONNECTED))
723		goto error;
724
725	client->status = Connected;
726
727	return 0;
728
729error:
730	rdma_destroy_trans(rdma);
731	return -ENOTCONN;
732}
733
734static struct p9_trans_module p9_rdma_trans = {
735	.name = "rdma",
736	.maxsize = P9_RDMA_MAXSIZE,
737	.def = 0,
738	.owner = THIS_MODULE,
739	.create = rdma_create_trans,
740	.close = rdma_close,
741	.request = rdma_request,
742	.cancel = rdma_cancel,
743	.cancelled = rdma_cancelled,
 
744};
745
746/**
747 * p9_trans_rdma_init - Register the 9P RDMA transport driver
748 */
749static int __init p9_trans_rdma_init(void)
750{
751	v9fs_register_trans(&p9_rdma_trans);
752	return 0;
753}
754
755static void __exit p9_trans_rdma_exit(void)
756{
757	v9fs_unregister_trans(&p9_rdma_trans);
758}
759
760module_init(p9_trans_rdma_init);
761module_exit(p9_trans_rdma_exit);
762
763MODULE_AUTHOR("Tom Tucker <tom@opengridcomputing.com>");
764MODULE_DESCRIPTION("RDMA Transport for 9P");
765MODULE_LICENSE("Dual BSD/GPL");