xref: /linux/net/sunrpc/xprtrdma/transport.c (revision ca55b2fef3a9373fcfc30f82fd26bc7fccbda732)
1 /*
2  * Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
3  *
4  * This software is available to you under a choice of one of two
5  * licenses.  You may choose to be licensed under the terms of the GNU
6  * General Public License (GPL) Version 2, available from the file
7  * COPYING in the main directory of this source tree, or the BSD-type
8  * license below:
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  *
14  *      Redistributions of source code must retain the above copyright
15  *      notice, this list of conditions and the following disclaimer.
16  *
17  *      Redistributions in binary form must reproduce the above
18  *      copyright notice, this list of conditions and the following
19  *      disclaimer in the documentation and/or other materials provided
20  *      with the distribution.
21  *
22  *      Neither the name of the Network Appliance, Inc. nor the names of
23  *      its contributors may be used to endorse or promote products
24  *      derived from this software without specific prior written
25  *      permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
28  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
29  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
30  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
31  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
32  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
33  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
34  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
35  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
36  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
37  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
38  */
39 
40 /*
41  * transport.c
42  *
43  * This file contains the top-level implementation of an RPC RDMA
44  * transport.
45  *
46  * Naming convention: functions beginning with xprt_ are part of the
47  * transport switch. All others are RPC RDMA internal.
48  */
49 
50 #include <linux/module.h>
51 #include <linux/slab.h>
52 #include <linux/seq_file.h>
53 #include <linux/sunrpc/addr.h>
54 
55 #include "xprt_rdma.h"
56 
57 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
58 # define RPCDBG_FACILITY	RPCDBG_TRANS
59 #endif
60 
61 /*
62  * tunables
63  */
64 
65 static unsigned int xprt_rdma_slot_table_entries = RPCRDMA_DEF_SLOT_TABLE;
66 static unsigned int xprt_rdma_max_inline_read = RPCRDMA_DEF_INLINE;
67 static unsigned int xprt_rdma_max_inline_write = RPCRDMA_DEF_INLINE;
68 static unsigned int xprt_rdma_inline_write_padding;
69 static unsigned int xprt_rdma_memreg_strategy = RPCRDMA_FRMR;
70 		int xprt_rdma_pad_optimize = 1;
71 
72 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
73 
74 static unsigned int min_slot_table_size = RPCRDMA_MIN_SLOT_TABLE;
75 static unsigned int max_slot_table_size = RPCRDMA_MAX_SLOT_TABLE;
76 static unsigned int zero;
77 static unsigned int max_padding = PAGE_SIZE;
78 static unsigned int min_memreg = RPCRDMA_BOUNCEBUFFERS;
79 static unsigned int max_memreg = RPCRDMA_LAST - 1;
80 
81 static struct ctl_table_header *sunrpc_table_header;
82 
83 static struct ctl_table xr_tunables_table[] = {
84 	{
85 		.procname	= "rdma_slot_table_entries",
86 		.data		= &xprt_rdma_slot_table_entries,
87 		.maxlen		= sizeof(unsigned int),
88 		.mode		= 0644,
89 		.proc_handler	= proc_dointvec_minmax,
90 		.extra1		= &min_slot_table_size,
91 		.extra2		= &max_slot_table_size
92 	},
93 	{
94 		.procname	= "rdma_max_inline_read",
95 		.data		= &xprt_rdma_max_inline_read,
96 		.maxlen		= sizeof(unsigned int),
97 		.mode		= 0644,
98 		.proc_handler	= proc_dointvec,
99 	},
100 	{
101 		.procname	= "rdma_max_inline_write",
102 		.data		= &xprt_rdma_max_inline_write,
103 		.maxlen		= sizeof(unsigned int),
104 		.mode		= 0644,
105 		.proc_handler	= proc_dointvec,
106 	},
107 	{
108 		.procname	= "rdma_inline_write_padding",
109 		.data		= &xprt_rdma_inline_write_padding,
110 		.maxlen		= sizeof(unsigned int),
111 		.mode		= 0644,
112 		.proc_handler	= proc_dointvec_minmax,
113 		.extra1		= &zero,
114 		.extra2		= &max_padding,
115 	},
116 	{
117 		.procname	= "rdma_memreg_strategy",
118 		.data		= &xprt_rdma_memreg_strategy,
119 		.maxlen		= sizeof(unsigned int),
120 		.mode		= 0644,
121 		.proc_handler	= proc_dointvec_minmax,
122 		.extra1		= &min_memreg,
123 		.extra2		= &max_memreg,
124 	},
125 	{
126 		.procname	= "rdma_pad_optimize",
127 		.data		= &xprt_rdma_pad_optimize,
128 		.maxlen		= sizeof(unsigned int),
129 		.mode		= 0644,
130 		.proc_handler	= proc_dointvec,
131 	},
132 	{ },
133 };
134 
135 static struct ctl_table sunrpc_table[] = {
136 	{
137 		.procname	= "sunrpc",
138 		.mode		= 0555,
139 		.child		= xr_tunables_table
140 	},
141 	{ },
142 };
143 
144 #endif
145 
146 #define RPCRDMA_BIND_TO		(60U * HZ)
147 #define RPCRDMA_INIT_REEST_TO	(5U * HZ)
148 #define RPCRDMA_MAX_REEST_TO	(30U * HZ)
149 #define RPCRDMA_IDLE_DISC_TO	(5U * 60 * HZ)
150 
151 static struct rpc_xprt_ops xprt_rdma_procs;	/* forward reference */
152 
153 static void
154 xprt_rdma_format_addresses4(struct rpc_xprt *xprt, struct sockaddr *sap)
155 {
156 	struct sockaddr_in *sin = (struct sockaddr_in *)sap;
157 	char buf[20];
158 
159 	snprintf(buf, sizeof(buf), "%08x", ntohl(sin->sin_addr.s_addr));
160 	xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = kstrdup(buf, GFP_KERNEL);
161 
162 	xprt->address_strings[RPC_DISPLAY_NETID] = RPCBIND_NETID_RDMA;
163 }
164 
165 static void
166 xprt_rdma_format_addresses6(struct rpc_xprt *xprt, struct sockaddr *sap)
167 {
168 	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
169 	char buf[40];
170 
171 	snprintf(buf, sizeof(buf), "%pi6", &sin6->sin6_addr);
172 	xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = kstrdup(buf, GFP_KERNEL);
173 
174 	xprt->address_strings[RPC_DISPLAY_NETID] = RPCBIND_NETID_RDMA6;
175 }
176 
177 static void
178 xprt_rdma_format_addresses(struct rpc_xprt *xprt, struct sockaddr *sap)
179 {
180 	char buf[128];
181 
182 	switch (sap->sa_family) {
183 	case AF_INET:
184 		xprt_rdma_format_addresses4(xprt, sap);
185 		break;
186 	case AF_INET6:
187 		xprt_rdma_format_addresses6(xprt, sap);
188 		break;
189 	default:
190 		pr_err("rpcrdma: Unrecognized address family\n");
191 		return;
192 	}
193 
194 	(void)rpc_ntop(sap, buf, sizeof(buf));
195 	xprt->address_strings[RPC_DISPLAY_ADDR] = kstrdup(buf, GFP_KERNEL);
196 
197 	snprintf(buf, sizeof(buf), "%u", rpc_get_port(sap));
198 	xprt->address_strings[RPC_DISPLAY_PORT] = kstrdup(buf, GFP_KERNEL);
199 
200 	snprintf(buf, sizeof(buf), "%4hx", rpc_get_port(sap));
201 	xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);
202 
203 	xprt->address_strings[RPC_DISPLAY_PROTO] = "rdma";
204 }
205 
206 static void
207 xprt_rdma_free_addresses(struct rpc_xprt *xprt)
208 {
209 	unsigned int i;
210 
211 	for (i = 0; i < RPC_DISPLAY_MAX; i++)
212 		switch (i) {
213 		case RPC_DISPLAY_PROTO:
214 		case RPC_DISPLAY_NETID:
215 			continue;
216 		default:
217 			kfree(xprt->address_strings[i]);
218 		}
219 }
220 
221 static void
222 xprt_rdma_connect_worker(struct work_struct *work)
223 {
224 	struct rpcrdma_xprt *r_xprt = container_of(work, struct rpcrdma_xprt,
225 						   rx_connect_worker.work);
226 	struct rpc_xprt *xprt = &r_xprt->rx_xprt;
227 	int rc = 0;
228 
229 	xprt_clear_connected(xprt);
230 
231 	dprintk("RPC:       %s: %sconnect\n", __func__,
232 			r_xprt->rx_ep.rep_connected != 0 ? "re" : "");
233 	rc = rpcrdma_ep_connect(&r_xprt->rx_ep, &r_xprt->rx_ia);
234 	if (rc)
235 		xprt_wake_pending_tasks(xprt, rc);
236 
237 	dprintk("RPC:       %s: exit\n", __func__);
238 	xprt_clear_connecting(xprt);
239 }
240 
241 static void
242 xprt_rdma_inject_disconnect(struct rpc_xprt *xprt)
243 {
244 	struct rpcrdma_xprt *r_xprt = container_of(xprt, struct rpcrdma_xprt,
245 						   rx_xprt);
246 
247 	pr_info("rpcrdma: injecting transport disconnect on xprt=%p\n", xprt);
248 	rdma_disconnect(r_xprt->rx_ia.ri_id);
249 }
250 
251 /*
252  * xprt_rdma_destroy
253  *
254  * Destroy the xprt.
255  * Free all memory associated with the object, including its own.
256  * NOTE: none of the *destroy methods free memory for their top-level
257  * objects, even though they may have allocated it (they do free
258  * private memory). It's up to the caller to handle it. In this
259  * case (RDMA transport), all structure memory is inlined with the
260  * struct rpcrdma_xprt.
261  */
262 static void
263 xprt_rdma_destroy(struct rpc_xprt *xprt)
264 {
265 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
266 
267 	dprintk("RPC:       %s: called\n", __func__);
268 
269 	cancel_delayed_work_sync(&r_xprt->rx_connect_worker);
270 
271 	xprt_clear_connected(xprt);
272 
273 	rpcrdma_ep_destroy(&r_xprt->rx_ep, &r_xprt->rx_ia);
274 	rpcrdma_buffer_destroy(&r_xprt->rx_buf);
275 	rpcrdma_ia_close(&r_xprt->rx_ia);
276 
277 	xprt_rdma_free_addresses(xprt);
278 
279 	xprt_free(xprt);
280 
281 	dprintk("RPC:       %s: returning\n", __func__);
282 
283 	module_put(THIS_MODULE);
284 }
285 
286 static const struct rpc_timeout xprt_rdma_default_timeout = {
287 	.to_initval = 60 * HZ,
288 	.to_maxval = 60 * HZ,
289 };
290 
291 /**
292  * xprt_setup_rdma - Set up transport to use RDMA
293  *
294  * @args: rpc transport arguments
295  */
296 static struct rpc_xprt *
297 xprt_setup_rdma(struct xprt_create *args)
298 {
299 	struct rpcrdma_create_data_internal cdata;
300 	struct rpc_xprt *xprt;
301 	struct rpcrdma_xprt *new_xprt;
302 	struct rpcrdma_ep *new_ep;
303 	struct sockaddr *sap;
304 	int rc;
305 
306 	if (args->addrlen > sizeof(xprt->addr)) {
307 		dprintk("RPC:       %s: address too large\n", __func__);
308 		return ERR_PTR(-EBADF);
309 	}
310 
311 	xprt = xprt_alloc(args->net, sizeof(struct rpcrdma_xprt),
312 			xprt_rdma_slot_table_entries,
313 			xprt_rdma_slot_table_entries);
314 	if (xprt == NULL) {
315 		dprintk("RPC:       %s: couldn't allocate rpcrdma_xprt\n",
316 			__func__);
317 		return ERR_PTR(-ENOMEM);
318 	}
319 
320 	/* 60 second timeout, no retries */
321 	xprt->timeout = &xprt_rdma_default_timeout;
322 	xprt->bind_timeout = RPCRDMA_BIND_TO;
323 	xprt->reestablish_timeout = RPCRDMA_INIT_REEST_TO;
324 	xprt->idle_timeout = RPCRDMA_IDLE_DISC_TO;
325 
326 	xprt->resvport = 0;		/* privileged port not needed */
327 	xprt->tsh_size = 0;		/* RPC-RDMA handles framing */
328 	xprt->ops = &xprt_rdma_procs;
329 
330 	/*
331 	 * Set up RDMA-specific connect data.
332 	 */
333 
334 	sap = (struct sockaddr *)&cdata.addr;
335 	memcpy(sap, args->dstaddr, args->addrlen);
336 
337 	/* Ensure xprt->addr holds valid server TCP (not RDMA)
338 	 * address, for any side protocols which peek at it */
339 	xprt->prot = IPPROTO_TCP;
340 	xprt->addrlen = args->addrlen;
341 	memcpy(&xprt->addr, sap, xprt->addrlen);
342 
343 	if (rpc_get_port(sap))
344 		xprt_set_bound(xprt);
345 
346 	cdata.max_requests = xprt->max_reqs;
347 
348 	cdata.rsize = RPCRDMA_MAX_SEGS * PAGE_SIZE; /* RDMA write max */
349 	cdata.wsize = RPCRDMA_MAX_SEGS * PAGE_SIZE; /* RDMA read max */
350 
351 	cdata.inline_wsize = xprt_rdma_max_inline_write;
352 	if (cdata.inline_wsize > cdata.wsize)
353 		cdata.inline_wsize = cdata.wsize;
354 
355 	cdata.inline_rsize = xprt_rdma_max_inline_read;
356 	if (cdata.inline_rsize > cdata.rsize)
357 		cdata.inline_rsize = cdata.rsize;
358 
359 	cdata.padding = xprt_rdma_inline_write_padding;
360 
361 	/*
362 	 * Create new transport instance, which includes initialized
363 	 *  o ia
364 	 *  o endpoint
365 	 *  o buffers
366 	 */
367 
368 	new_xprt = rpcx_to_rdmax(xprt);
369 
370 	rc = rpcrdma_ia_open(new_xprt, sap, xprt_rdma_memreg_strategy);
371 	if (rc)
372 		goto out1;
373 
374 	/*
375 	 * initialize and create ep
376 	 */
377 	new_xprt->rx_data = cdata;
378 	new_ep = &new_xprt->rx_ep;
379 	new_ep->rep_remote_addr = cdata.addr;
380 
381 	rc = rpcrdma_ep_create(&new_xprt->rx_ep,
382 				&new_xprt->rx_ia, &new_xprt->rx_data);
383 	if (rc)
384 		goto out2;
385 
386 	/*
387 	 * Allocate pre-registered send and receive buffers for headers and
388 	 * any inline data. Also specify any padding which will be provided
389 	 * from a preregistered zero buffer.
390 	 */
391 	rc = rpcrdma_buffer_create(new_xprt);
392 	if (rc)
393 		goto out3;
394 
395 	/*
396 	 * Register a callback for connection events. This is necessary because
397 	 * connection loss notification is async. We also catch connection loss
398 	 * when reaping receives.
399 	 */
400 	INIT_DELAYED_WORK(&new_xprt->rx_connect_worker,
401 			  xprt_rdma_connect_worker);
402 
403 	xprt_rdma_format_addresses(xprt, sap);
404 	xprt->max_payload = new_xprt->rx_ia.ri_ops->ro_maxpages(new_xprt);
405 	if (xprt->max_payload == 0)
406 		goto out4;
407 	xprt->max_payload <<= PAGE_SHIFT;
408 	dprintk("RPC:       %s: transport data payload maximum: %zu bytes\n",
409 		__func__, xprt->max_payload);
410 
411 	if (!try_module_get(THIS_MODULE))
412 		goto out4;
413 
414 	dprintk("RPC:       %s: %s:%s\n", __func__,
415 		xprt->address_strings[RPC_DISPLAY_ADDR],
416 		xprt->address_strings[RPC_DISPLAY_PORT]);
417 	return xprt;
418 
419 out4:
420 	xprt_rdma_free_addresses(xprt);
421 	rc = -EINVAL;
422 out3:
423 	rpcrdma_ep_destroy(new_ep, &new_xprt->rx_ia);
424 out2:
425 	rpcrdma_ia_close(&new_xprt->rx_ia);
426 out1:
427 	xprt_free(xprt);
428 	return ERR_PTR(rc);
429 }
430 
431 /*
432  * Close a connection, during shutdown or timeout/reconnect
433  */
434 static void
435 xprt_rdma_close(struct rpc_xprt *xprt)
436 {
437 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
438 
439 	dprintk("RPC:       %s: closing\n", __func__);
440 	if (r_xprt->rx_ep.rep_connected > 0)
441 		xprt->reestablish_timeout = 0;
442 	xprt_disconnect_done(xprt);
443 	rpcrdma_ep_disconnect(&r_xprt->rx_ep, &r_xprt->rx_ia);
444 }
445 
446 static void
447 xprt_rdma_set_port(struct rpc_xprt *xprt, u16 port)
448 {
449 	struct sockaddr_in *sap;
450 
451 	sap = (struct sockaddr_in *)&xprt->addr;
452 	sap->sin_port = htons(port);
453 	sap = (struct sockaddr_in *)&rpcx_to_rdmad(xprt).addr;
454 	sap->sin_port = htons(port);
455 	dprintk("RPC:       %s: %u\n", __func__, port);
456 }
457 
458 static void
459 xprt_rdma_connect(struct rpc_xprt *xprt, struct rpc_task *task)
460 {
461 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
462 
463 	if (r_xprt->rx_ep.rep_connected != 0) {
464 		/* Reconnect */
465 		schedule_delayed_work(&r_xprt->rx_connect_worker,
466 				      xprt->reestablish_timeout);
467 		xprt->reestablish_timeout <<= 1;
468 		if (xprt->reestablish_timeout > RPCRDMA_MAX_REEST_TO)
469 			xprt->reestablish_timeout = RPCRDMA_MAX_REEST_TO;
470 		else if (xprt->reestablish_timeout < RPCRDMA_INIT_REEST_TO)
471 			xprt->reestablish_timeout = RPCRDMA_INIT_REEST_TO;
472 	} else {
473 		schedule_delayed_work(&r_xprt->rx_connect_worker, 0);
474 		if (!RPC_IS_ASYNC(task))
475 			flush_delayed_work(&r_xprt->rx_connect_worker);
476 	}
477 }
478 
479 /*
480  * The RDMA allocate/free functions need the task structure as a place
481  * to hide the struct rpcrdma_req, which is necessary for the actual send/recv
482  * sequence.
483  *
484  * The RPC layer allocates both send and receive buffers in the same call
485  * (rq_send_buf and rq_rcv_buf are both part of a single contiguous buffer).
486  * We may register rq_rcv_buf when using reply chunks.
487  */
488 static void *
489 xprt_rdma_allocate(struct rpc_task *task, size_t size)
490 {
491 	struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
492 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
493 	struct rpcrdma_regbuf *rb;
494 	struct rpcrdma_req *req;
495 	size_t min_size;
496 	gfp_t flags;
497 
498 	req = rpcrdma_buffer_get(&r_xprt->rx_buf);
499 	if (req == NULL)
500 		return NULL;
501 
502 	flags = GFP_NOIO | __GFP_NOWARN;
503 	if (RPC_IS_SWAPPER(task))
504 		flags = __GFP_MEMALLOC | GFP_NOWAIT | __GFP_NOWARN;
505 
506 	if (req->rl_rdmabuf == NULL)
507 		goto out_rdmabuf;
508 	if (req->rl_sendbuf == NULL)
509 		goto out_sendbuf;
510 	if (size > req->rl_sendbuf->rg_size)
511 		goto out_sendbuf;
512 
513 out:
514 	dprintk("RPC:       %s: size %zd, request 0x%p\n", __func__, size, req);
515 	req->rl_connect_cookie = 0;	/* our reserved value */
516 	return req->rl_sendbuf->rg_base;
517 
518 out_rdmabuf:
519 	min_size = RPCRDMA_INLINE_WRITE_THRESHOLD(task->tk_rqstp);
520 	rb = rpcrdma_alloc_regbuf(&r_xprt->rx_ia, min_size, flags);
521 	if (IS_ERR(rb))
522 		goto out_fail;
523 	req->rl_rdmabuf = rb;
524 
525 out_sendbuf:
526 	/* XDR encoding and RPC/RDMA marshaling of this request has not
527 	 * yet occurred. Thus a lower bound is needed to prevent buffer
528 	 * overrun during marshaling.
529 	 *
530 	 * RPC/RDMA marshaling may choose to send payload bearing ops
531 	 * inline, if the result is smaller than the inline threshold.
532 	 * The value of the "size" argument accounts for header
533 	 * requirements but not for the payload in these cases.
534 	 *
535 	 * Likewise, allocate enough space to receive a reply up to the
536 	 * size of the inline threshold.
537 	 *
538 	 * It's unlikely that both the send header and the received
539 	 * reply will be large, but slush is provided here to allow
540 	 * flexibility when marshaling.
541 	 */
542 	min_size = RPCRDMA_INLINE_READ_THRESHOLD(task->tk_rqstp);
543 	min_size += RPCRDMA_INLINE_WRITE_THRESHOLD(task->tk_rqstp);
544 	if (size < min_size)
545 		size = min_size;
546 
547 	rb = rpcrdma_alloc_regbuf(&r_xprt->rx_ia, size, flags);
548 	if (IS_ERR(rb))
549 		goto out_fail;
550 	rb->rg_owner = req;
551 
552 	r_xprt->rx_stats.hardway_register_count += size;
553 	rpcrdma_free_regbuf(&r_xprt->rx_ia, req->rl_sendbuf);
554 	req->rl_sendbuf = rb;
555 	goto out;
556 
557 out_fail:
558 	rpcrdma_buffer_put(req);
559 	r_xprt->rx_stats.failed_marshal_count++;
560 	return NULL;
561 }
562 
563 /*
564  * This function returns all RDMA resources to the pool.
565  */
566 static void
567 xprt_rdma_free(void *buffer)
568 {
569 	struct rpcrdma_req *req;
570 	struct rpcrdma_xprt *r_xprt;
571 	struct rpcrdma_regbuf *rb;
572 	int i;
573 
574 	if (buffer == NULL)
575 		return;
576 
577 	rb = container_of(buffer, struct rpcrdma_regbuf, rg_base[0]);
578 	req = rb->rg_owner;
579 	r_xprt = container_of(req->rl_buffer, struct rpcrdma_xprt, rx_buf);
580 
581 	dprintk("RPC:       %s: called on 0x%p\n", __func__, req->rl_reply);
582 
583 	for (i = 0; req->rl_nchunks;) {
584 		--req->rl_nchunks;
585 		i += r_xprt->rx_ia.ri_ops->ro_unmap(r_xprt,
586 						    &req->rl_segments[i]);
587 	}
588 
589 	rpcrdma_buffer_put(req);
590 }
591 
592 /*
593  * send_request invokes the meat of RPC RDMA. It must do the following:
594  *  1.  Marshal the RPC request into an RPC RDMA request, which means
595  *	putting a header in front of data, and creating IOVs for RDMA
596  *	from those in the request.
597  *  2.  In marshaling, detect opportunities for RDMA, and use them.
598  *  3.  Post a recv message to set up asynch completion, then send
599  *	the request (rpcrdma_ep_post).
600  *  4.  No partial sends are possible in the RPC-RDMA protocol (as in UDP).
601  */
602 
603 static int
604 xprt_rdma_send_request(struct rpc_task *task)
605 {
606 	struct rpc_rqst *rqst = task->tk_rqstp;
607 	struct rpc_xprt *xprt = rqst->rq_xprt;
608 	struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
609 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
610 	int rc = 0;
611 
612 	rc = rpcrdma_marshal_req(rqst);
613 	if (rc < 0)
614 		goto failed_marshal;
615 
616 	if (req->rl_reply == NULL) 		/* e.g. reconnection */
617 		rpcrdma_recv_buffer_get(req);
618 
619 	/* Must suppress retransmit to maintain credits */
620 	if (req->rl_connect_cookie == xprt->connect_cookie)
621 		goto drop_connection;
622 	req->rl_connect_cookie = xprt->connect_cookie;
623 
624 	if (rpcrdma_ep_post(&r_xprt->rx_ia, &r_xprt->rx_ep, req))
625 		goto drop_connection;
626 
627 	rqst->rq_xmit_bytes_sent += rqst->rq_snd_buf.len;
628 	rqst->rq_bytes_sent = 0;
629 	return 0;
630 
631 failed_marshal:
632 	r_xprt->rx_stats.failed_marshal_count++;
633 	dprintk("RPC:       %s: rpcrdma_marshal_req failed, status %i\n",
634 		__func__, rc);
635 	if (rc == -EIO)
636 		return -EIO;
637 drop_connection:
638 	xprt_disconnect_done(xprt);
639 	return -ENOTCONN;	/* implies disconnect */
640 }
641 
642 static void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
643 {
644 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
645 	long idle_time = 0;
646 
647 	if (xprt_connected(xprt))
648 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
649 
650 	seq_puts(seq, "\txprt:\trdma ");
651 	seq_printf(seq, "%u %lu %lu %lu %ld %lu %lu %lu %llu %llu ",
652 		   0,	/* need a local port? */
653 		   xprt->stat.bind_count,
654 		   xprt->stat.connect_count,
655 		   xprt->stat.connect_time,
656 		   idle_time,
657 		   xprt->stat.sends,
658 		   xprt->stat.recvs,
659 		   xprt->stat.bad_xids,
660 		   xprt->stat.req_u,
661 		   xprt->stat.bklog_u);
662 	seq_printf(seq, "%lu %lu %lu %llu %llu %llu %llu %lu %lu %lu %lu\n",
663 		   r_xprt->rx_stats.read_chunk_count,
664 		   r_xprt->rx_stats.write_chunk_count,
665 		   r_xprt->rx_stats.reply_chunk_count,
666 		   r_xprt->rx_stats.total_rdma_request,
667 		   r_xprt->rx_stats.total_rdma_reply,
668 		   r_xprt->rx_stats.pullup_copy_count,
669 		   r_xprt->rx_stats.fixup_copy_count,
670 		   r_xprt->rx_stats.hardway_register_count,
671 		   r_xprt->rx_stats.failed_marshal_count,
672 		   r_xprt->rx_stats.bad_reply_count,
673 		   r_xprt->rx_stats.nomsg_call_count);
674 }
675 
676 static int
677 xprt_rdma_enable_swap(struct rpc_xprt *xprt)
678 {
679 	return -EINVAL;
680 }
681 
682 static void
683 xprt_rdma_disable_swap(struct rpc_xprt *xprt)
684 {
685 }
686 
687 /*
688  * Plumbing for rpc transport switch and kernel module
689  */
690 
691 static struct rpc_xprt_ops xprt_rdma_procs = {
692 	.reserve_xprt		= xprt_reserve_xprt_cong,
693 	.release_xprt		= xprt_release_xprt_cong, /* sunrpc/xprt.c */
694 	.alloc_slot		= xprt_alloc_slot,
695 	.release_request	= xprt_release_rqst_cong,       /* ditto */
696 	.set_retrans_timeout	= xprt_set_retrans_timeout_def, /* ditto */
697 	.rpcbind		= rpcb_getport_async,	/* sunrpc/rpcb_clnt.c */
698 	.set_port		= xprt_rdma_set_port,
699 	.connect		= xprt_rdma_connect,
700 	.buf_alloc		= xprt_rdma_allocate,
701 	.buf_free		= xprt_rdma_free,
702 	.send_request		= xprt_rdma_send_request,
703 	.close			= xprt_rdma_close,
704 	.destroy		= xprt_rdma_destroy,
705 	.print_stats		= xprt_rdma_print_stats,
706 	.enable_swap		= xprt_rdma_enable_swap,
707 	.disable_swap		= xprt_rdma_disable_swap,
708 	.inject_disconnect	= xprt_rdma_inject_disconnect
709 };
710 
711 static struct xprt_class xprt_rdma = {
712 	.list			= LIST_HEAD_INIT(xprt_rdma.list),
713 	.name			= "rdma",
714 	.owner			= THIS_MODULE,
715 	.ident			= XPRT_TRANSPORT_RDMA,
716 	.setup			= xprt_setup_rdma,
717 };
718 
719 void xprt_rdma_cleanup(void)
720 {
721 	int rc;
722 
723 	dprintk("RPCRDMA Module Removed, deregister RPC RDMA transport\n");
724 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
725 	if (sunrpc_table_header) {
726 		unregister_sysctl_table(sunrpc_table_header);
727 		sunrpc_table_header = NULL;
728 	}
729 #endif
730 	rc = xprt_unregister_transport(&xprt_rdma);
731 	if (rc)
732 		dprintk("RPC:       %s: xprt_unregister returned %i\n",
733 			__func__, rc);
734 
735 	frwr_destroy_recovery_wq();
736 }
737 
738 int xprt_rdma_init(void)
739 {
740 	int rc;
741 
742 	rc = frwr_alloc_recovery_wq();
743 	if (rc)
744 		return rc;
745 
746 	rc = xprt_register_transport(&xprt_rdma);
747 	if (rc) {
748 		frwr_destroy_recovery_wq();
749 		return rc;
750 	}
751 
752 	dprintk("RPCRDMA Module Init, register RPC RDMA transport\n");
753 
754 	dprintk("Defaults:\n");
755 	dprintk("\tSlots %d\n"
756 		"\tMaxInlineRead %d\n\tMaxInlineWrite %d\n",
757 		xprt_rdma_slot_table_entries,
758 		xprt_rdma_max_inline_read, xprt_rdma_max_inline_write);
759 	dprintk("\tPadding %d\n\tMemreg %d\n",
760 		xprt_rdma_inline_write_padding, xprt_rdma_memreg_strategy);
761 
762 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
763 	if (!sunrpc_table_header)
764 		sunrpc_table_header = register_sysctl_table(sunrpc_table);
765 #endif
766 	return 0;
767 }
768