xref: /openbmc/linux/net/sunrpc/xprtrdma/transport.c (revision c4a54f70)
1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
2 /*
3  * Copyright (c) 2014-2017 Oracle.  All rights reserved.
4  * Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
5  *
6  * This software is available to you under a choice of one of two
7  * licenses.  You may choose to be licensed under the terms of the GNU
8  * General Public License (GPL) Version 2, available from the file
9  * COPYING in the main directory of this source tree, or the BSD-type
10  * license below:
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  *
16  *      Redistributions of source code must retain the above copyright
17  *      notice, this list of conditions and the following disclaimer.
18  *
19  *      Redistributions in binary form must reproduce the above
20  *      copyright notice, this list of conditions and the following
21  *      disclaimer in the documentation and/or other materials provided
22  *      with the distribution.
23  *
24  *      Neither the name of the Network Appliance, Inc. nor the names of
25  *      its contributors may be used to endorse or promote products
26  *      derived from this software without specific prior written
27  *      permission.
28  *
29  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
30  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
31  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
32  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
33  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
34  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
35  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
39  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40  */
41 
42 /*
43  * transport.c
44  *
45  * This file contains the top-level implementation of an RPC RDMA
46  * transport.
47  *
48  * Naming convention: functions beginning with xprt_ are part of the
49  * transport switch. All others are RPC RDMA internal.
50  */
51 
52 #include <linux/module.h>
53 #include <linux/slab.h>
54 #include <linux/seq_file.h>
55 #include <linux/smp.h>
56 
57 #include <linux/sunrpc/addr.h>
58 #include <linux/sunrpc/svc_rdma.h>
59 
60 #include "xprt_rdma.h"
61 #include <trace/events/rpcrdma.h>
62 
63 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
64 # define RPCDBG_FACILITY	RPCDBG_TRANS
65 #endif
66 
67 /*
68  * tunables
69  */
70 
71 static unsigned int xprt_rdma_slot_table_entries = RPCRDMA_DEF_SLOT_TABLE;
72 unsigned int xprt_rdma_max_inline_read = RPCRDMA_DEF_INLINE;
73 unsigned int xprt_rdma_max_inline_write = RPCRDMA_DEF_INLINE;
74 unsigned int xprt_rdma_memreg_strategy		= RPCRDMA_FRWR;
75 int xprt_rdma_pad_optimize;
76 
77 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
78 
79 static unsigned int min_slot_table_size = RPCRDMA_MIN_SLOT_TABLE;
80 static unsigned int max_slot_table_size = RPCRDMA_MAX_SLOT_TABLE;
81 static unsigned int min_inline_size = RPCRDMA_MIN_INLINE;
82 static unsigned int max_inline_size = RPCRDMA_MAX_INLINE;
83 static unsigned int max_padding = PAGE_SIZE;
84 static unsigned int min_memreg = RPCRDMA_BOUNCEBUFFERS;
85 static unsigned int max_memreg = RPCRDMA_LAST - 1;
86 static unsigned int dummy;
87 
88 static struct ctl_table_header *sunrpc_table_header;
89 
90 static struct ctl_table xr_tunables_table[] = {
91 	{
92 		.procname	= "rdma_slot_table_entries",
93 		.data		= &xprt_rdma_slot_table_entries,
94 		.maxlen		= sizeof(unsigned int),
95 		.mode		= 0644,
96 		.proc_handler	= proc_dointvec_minmax,
97 		.extra1		= &min_slot_table_size,
98 		.extra2		= &max_slot_table_size
99 	},
100 	{
101 		.procname	= "rdma_max_inline_read",
102 		.data		= &xprt_rdma_max_inline_read,
103 		.maxlen		= sizeof(unsigned int),
104 		.mode		= 0644,
105 		.proc_handler	= proc_dointvec_minmax,
106 		.extra1		= &min_inline_size,
107 		.extra2		= &max_inline_size,
108 	},
109 	{
110 		.procname	= "rdma_max_inline_write",
111 		.data		= &xprt_rdma_max_inline_write,
112 		.maxlen		= sizeof(unsigned int),
113 		.mode		= 0644,
114 		.proc_handler	= proc_dointvec_minmax,
115 		.extra1		= &min_inline_size,
116 		.extra2		= &max_inline_size,
117 	},
118 	{
119 		.procname	= "rdma_inline_write_padding",
120 		.data		= &dummy,
121 		.maxlen		= sizeof(unsigned int),
122 		.mode		= 0644,
123 		.proc_handler	= proc_dointvec_minmax,
124 		.extra1		= SYSCTL_ZERO,
125 		.extra2		= &max_padding,
126 	},
127 	{
128 		.procname	= "rdma_memreg_strategy",
129 		.data		= &xprt_rdma_memreg_strategy,
130 		.maxlen		= sizeof(unsigned int),
131 		.mode		= 0644,
132 		.proc_handler	= proc_dointvec_minmax,
133 		.extra1		= &min_memreg,
134 		.extra2		= &max_memreg,
135 	},
136 	{
137 		.procname	= "rdma_pad_optimize",
138 		.data		= &xprt_rdma_pad_optimize,
139 		.maxlen		= sizeof(unsigned int),
140 		.mode		= 0644,
141 		.proc_handler	= proc_dointvec,
142 	},
143 	{ },
144 };
145 
146 static struct ctl_table sunrpc_table[] = {
147 	{
148 		.procname	= "sunrpc",
149 		.mode		= 0555,
150 		.child		= xr_tunables_table
151 	},
152 	{ },
153 };
154 
155 #endif
156 
157 static const struct rpc_xprt_ops xprt_rdma_procs;
158 
159 static void
160 xprt_rdma_format_addresses4(struct rpc_xprt *xprt, struct sockaddr *sap)
161 {
162 	struct sockaddr_in *sin = (struct sockaddr_in *)sap;
163 	char buf[20];
164 
165 	snprintf(buf, sizeof(buf), "%08x", ntohl(sin->sin_addr.s_addr));
166 	xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = kstrdup(buf, GFP_KERNEL);
167 
168 	xprt->address_strings[RPC_DISPLAY_NETID] = RPCBIND_NETID_RDMA;
169 }
170 
171 static void
172 xprt_rdma_format_addresses6(struct rpc_xprt *xprt, struct sockaddr *sap)
173 {
174 	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
175 	char buf[40];
176 
177 	snprintf(buf, sizeof(buf), "%pi6", &sin6->sin6_addr);
178 	xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = kstrdup(buf, GFP_KERNEL);
179 
180 	xprt->address_strings[RPC_DISPLAY_NETID] = RPCBIND_NETID_RDMA6;
181 }
182 
183 void
184 xprt_rdma_format_addresses(struct rpc_xprt *xprt, struct sockaddr *sap)
185 {
186 	char buf[128];
187 
188 	switch (sap->sa_family) {
189 	case AF_INET:
190 		xprt_rdma_format_addresses4(xprt, sap);
191 		break;
192 	case AF_INET6:
193 		xprt_rdma_format_addresses6(xprt, sap);
194 		break;
195 	default:
196 		pr_err("rpcrdma: Unrecognized address family\n");
197 		return;
198 	}
199 
200 	(void)rpc_ntop(sap, buf, sizeof(buf));
201 	xprt->address_strings[RPC_DISPLAY_ADDR] = kstrdup(buf, GFP_KERNEL);
202 
203 	snprintf(buf, sizeof(buf), "%u", rpc_get_port(sap));
204 	xprt->address_strings[RPC_DISPLAY_PORT] = kstrdup(buf, GFP_KERNEL);
205 
206 	snprintf(buf, sizeof(buf), "%4hx", rpc_get_port(sap));
207 	xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);
208 
209 	xprt->address_strings[RPC_DISPLAY_PROTO] = "rdma";
210 }
211 
212 void
213 xprt_rdma_free_addresses(struct rpc_xprt *xprt)
214 {
215 	unsigned int i;
216 
217 	for (i = 0; i < RPC_DISPLAY_MAX; i++)
218 		switch (i) {
219 		case RPC_DISPLAY_PROTO:
220 		case RPC_DISPLAY_NETID:
221 			continue;
222 		default:
223 			kfree(xprt->address_strings[i]);
224 		}
225 }
226 
227 /**
228  * xprt_rdma_connect_worker - establish connection in the background
229  * @work: worker thread context
230  *
231  * Requester holds the xprt's send lock to prevent activity on this
232  * transport while a fresh connection is being established. RPC tasks
233  * sleep on the xprt's pending queue waiting for connect to complete.
234  */
235 static void
236 xprt_rdma_connect_worker(struct work_struct *work)
237 {
238 	struct rpcrdma_xprt *r_xprt = container_of(work, struct rpcrdma_xprt,
239 						   rx_connect_worker.work);
240 	struct rpc_xprt *xprt = &r_xprt->rx_xprt;
241 	int rc;
242 
243 	rc = rpcrdma_xprt_connect(r_xprt);
244 	xprt_clear_connecting(xprt);
245 	if (r_xprt->rx_ep && r_xprt->rx_ep->re_connect_status > 0) {
246 		xprt->connect_cookie++;
247 		xprt->stat.connect_count++;
248 		xprt->stat.connect_time += (long)jiffies -
249 					   xprt->stat.connect_start;
250 		xprt_set_connected(xprt);
251 		rc = -EAGAIN;
252 	}
253 	xprt_wake_pending_tasks(xprt, rc);
254 }
255 
256 /**
257  * xprt_rdma_inject_disconnect - inject a connection fault
258  * @xprt: transport context
259  *
260  * If @xprt is connected, disconnect it to simulate spurious connection
261  * loss.
262  */
263 static void
264 xprt_rdma_inject_disconnect(struct rpc_xprt *xprt)
265 {
266 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
267 
268 	trace_xprtrdma_op_inject_dsc(r_xprt);
269 	rdma_disconnect(r_xprt->rx_ep->re_id);
270 }
271 
272 /**
273  * xprt_rdma_destroy - Full tear down of transport
274  * @xprt: doomed transport context
275  *
276  * Caller guarantees there will be no more calls to us with
277  * this @xprt.
278  */
279 static void
280 xprt_rdma_destroy(struct rpc_xprt *xprt)
281 {
282 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
283 
284 	cancel_delayed_work_sync(&r_xprt->rx_connect_worker);
285 
286 	rpcrdma_xprt_disconnect(r_xprt);
287 	rpcrdma_buffer_destroy(&r_xprt->rx_buf);
288 
289 	xprt_rdma_free_addresses(xprt);
290 	xprt_free(xprt);
291 
292 	module_put(THIS_MODULE);
293 }
294 
295 /* 60 second timeout, no retries */
296 static const struct rpc_timeout xprt_rdma_default_timeout = {
297 	.to_initval = 60 * HZ,
298 	.to_maxval = 60 * HZ,
299 };
300 
301 /**
302  * xprt_setup_rdma - Set up transport to use RDMA
303  *
304  * @args: rpc transport arguments
305  */
306 static struct rpc_xprt *
307 xprt_setup_rdma(struct xprt_create *args)
308 {
309 	struct rpc_xprt *xprt;
310 	struct rpcrdma_xprt *new_xprt;
311 	struct sockaddr *sap;
312 	int rc;
313 
314 	if (args->addrlen > sizeof(xprt->addr))
315 		return ERR_PTR(-EBADF);
316 
317 	if (!try_module_get(THIS_MODULE))
318 		return ERR_PTR(-EIO);
319 
320 	xprt = xprt_alloc(args->net, sizeof(struct rpcrdma_xprt), 0,
321 			  xprt_rdma_slot_table_entries);
322 	if (!xprt) {
323 		module_put(THIS_MODULE);
324 		return ERR_PTR(-ENOMEM);
325 	}
326 
327 	xprt->timeout = &xprt_rdma_default_timeout;
328 	xprt->connect_timeout = xprt->timeout->to_initval;
329 	xprt->max_reconnect_timeout = xprt->timeout->to_maxval;
330 	xprt->bind_timeout = RPCRDMA_BIND_TO;
331 	xprt->reestablish_timeout = RPCRDMA_INIT_REEST_TO;
332 	xprt->idle_timeout = RPCRDMA_IDLE_DISC_TO;
333 
334 	xprt->resvport = 0;		/* privileged port not needed */
335 	xprt->ops = &xprt_rdma_procs;
336 
337 	/*
338 	 * Set up RDMA-specific connect data.
339 	 */
340 	sap = args->dstaddr;
341 
342 	/* Ensure xprt->addr holds valid server TCP (not RDMA)
343 	 * address, for any side protocols which peek at it */
344 	xprt->prot = IPPROTO_TCP;
345 	xprt->addrlen = args->addrlen;
346 	memcpy(&xprt->addr, sap, xprt->addrlen);
347 
348 	if (rpc_get_port(sap))
349 		xprt_set_bound(xprt);
350 	xprt_rdma_format_addresses(xprt, sap);
351 
352 	new_xprt = rpcx_to_rdmax(xprt);
353 	rc = rpcrdma_buffer_create(new_xprt);
354 	if (rc) {
355 		xprt_rdma_free_addresses(xprt);
356 		xprt_free(xprt);
357 		module_put(THIS_MODULE);
358 		return ERR_PTR(rc);
359 	}
360 
361 	INIT_DELAYED_WORK(&new_xprt->rx_connect_worker,
362 			  xprt_rdma_connect_worker);
363 
364 	xprt->max_payload = RPCRDMA_MAX_DATA_SEGS << PAGE_SHIFT;
365 
366 	return xprt;
367 }
368 
369 /**
370  * xprt_rdma_close - close a transport connection
371  * @xprt: transport context
372  *
373  * Called during autoclose or device removal.
374  *
375  * Caller holds @xprt's send lock to prevent activity on this
376  * transport while the connection is torn down.
377  */
378 void xprt_rdma_close(struct rpc_xprt *xprt)
379 {
380 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
381 
382 	rpcrdma_xprt_disconnect(r_xprt);
383 
384 	xprt->reestablish_timeout = 0;
385 	++xprt->connect_cookie;
386 	xprt_disconnect_done(xprt);
387 }
388 
389 /**
390  * xprt_rdma_set_port - update server port with rpcbind result
391  * @xprt: controlling RPC transport
392  * @port: new port value
393  *
394  * Transport connect status is unchanged.
395  */
396 static void
397 xprt_rdma_set_port(struct rpc_xprt *xprt, u16 port)
398 {
399 	struct sockaddr *sap = (struct sockaddr *)&xprt->addr;
400 	char buf[8];
401 
402 	rpc_set_port(sap, port);
403 
404 	kfree(xprt->address_strings[RPC_DISPLAY_PORT]);
405 	snprintf(buf, sizeof(buf), "%u", port);
406 	xprt->address_strings[RPC_DISPLAY_PORT] = kstrdup(buf, GFP_KERNEL);
407 
408 	kfree(xprt->address_strings[RPC_DISPLAY_HEX_PORT]);
409 	snprintf(buf, sizeof(buf), "%4hx", port);
410 	xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);
411 
412 	trace_xprtrdma_op_setport(container_of(xprt, struct rpcrdma_xprt,
413 					       rx_xprt));
414 }
415 
416 /**
417  * xprt_rdma_timer - invoked when an RPC times out
418  * @xprt: controlling RPC transport
419  * @task: RPC task that timed out
420  *
421  * Invoked when the transport is still connected, but an RPC
422  * retransmit timeout occurs.
423  *
424  * Since RDMA connections don't have a keep-alive, forcibly
425  * disconnect and retry to connect. This drives full
426  * detection of the network path, and retransmissions of
427  * all pending RPCs.
428  */
429 static void
430 xprt_rdma_timer(struct rpc_xprt *xprt, struct rpc_task *task)
431 {
432 	xprt_force_disconnect(xprt);
433 }
434 
435 /**
436  * xprt_rdma_set_connect_timeout - set timeouts for establishing a connection
437  * @xprt: controlling transport instance
438  * @connect_timeout: reconnect timeout after client disconnects
439  * @reconnect_timeout: reconnect timeout after server disconnects
440  *
441  */
442 static void xprt_rdma_set_connect_timeout(struct rpc_xprt *xprt,
443 					  unsigned long connect_timeout,
444 					  unsigned long reconnect_timeout)
445 {
446 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
447 
448 	trace_xprtrdma_op_set_cto(r_xprt, connect_timeout, reconnect_timeout);
449 
450 	spin_lock(&xprt->transport_lock);
451 
452 	if (connect_timeout < xprt->connect_timeout) {
453 		struct rpc_timeout to;
454 		unsigned long initval;
455 
456 		to = *xprt->timeout;
457 		initval = connect_timeout;
458 		if (initval < RPCRDMA_INIT_REEST_TO << 1)
459 			initval = RPCRDMA_INIT_REEST_TO << 1;
460 		to.to_initval = initval;
461 		to.to_maxval = initval;
462 		r_xprt->rx_timeout = to;
463 		xprt->timeout = &r_xprt->rx_timeout;
464 		xprt->connect_timeout = connect_timeout;
465 	}
466 
467 	if (reconnect_timeout < xprt->max_reconnect_timeout)
468 		xprt->max_reconnect_timeout = reconnect_timeout;
469 
470 	spin_unlock(&xprt->transport_lock);
471 }
472 
473 /**
474  * xprt_rdma_connect - schedule an attempt to reconnect
475  * @xprt: transport state
476  * @task: RPC scheduler context (unused)
477  *
478  */
479 static void
480 xprt_rdma_connect(struct rpc_xprt *xprt, struct rpc_task *task)
481 {
482 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
483 	struct rpcrdma_ep *ep = r_xprt->rx_ep;
484 	unsigned long delay;
485 
486 	delay = 0;
487 	if (ep && ep->re_connect_status != 0) {
488 		delay = xprt_reconnect_delay(xprt);
489 		xprt_reconnect_backoff(xprt, RPCRDMA_INIT_REEST_TO);
490 	}
491 	trace_xprtrdma_op_connect(r_xprt, delay);
492 	queue_delayed_work(xprtiod_workqueue, &r_xprt->rx_connect_worker,
493 			   delay);
494 }
495 
496 /**
497  * xprt_rdma_alloc_slot - allocate an rpc_rqst
498  * @xprt: controlling RPC transport
499  * @task: RPC task requesting a fresh rpc_rqst
500  *
501  * tk_status values:
502  *	%0 if task->tk_rqstp points to a fresh rpc_rqst
503  *	%-EAGAIN if no rpc_rqst is available; queued on backlog
504  */
505 static void
506 xprt_rdma_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task)
507 {
508 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
509 	struct rpcrdma_req *req;
510 
511 	req = rpcrdma_buffer_get(&r_xprt->rx_buf);
512 	if (!req)
513 		goto out_sleep;
514 	task->tk_rqstp = &req->rl_slot;
515 	task->tk_status = 0;
516 	return;
517 
518 out_sleep:
519 	set_bit(XPRT_CONGESTED, &xprt->state);
520 	rpc_sleep_on(&xprt->backlog, task, NULL);
521 	task->tk_status = -EAGAIN;
522 }
523 
524 /**
525  * xprt_rdma_free_slot - release an rpc_rqst
526  * @xprt: controlling RPC transport
527  * @rqst: rpc_rqst to release
528  *
529  */
530 static void
531 xprt_rdma_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *rqst)
532 {
533 	struct rpcrdma_xprt *r_xprt =
534 		container_of(xprt, struct rpcrdma_xprt, rx_xprt);
535 
536 	memset(rqst, 0, sizeof(*rqst));
537 	rpcrdma_buffer_put(&r_xprt->rx_buf, rpcr_to_rdmar(rqst));
538 	if (unlikely(!rpc_wake_up_next(&xprt->backlog)))
539 		clear_bit(XPRT_CONGESTED, &xprt->state);
540 }
541 
542 static bool rpcrdma_check_regbuf(struct rpcrdma_xprt *r_xprt,
543 				 struct rpcrdma_regbuf *rb, size_t size,
544 				 gfp_t flags)
545 {
546 	if (unlikely(rdmab_length(rb) < size)) {
547 		if (!rpcrdma_regbuf_realloc(rb, size, flags))
548 			return false;
549 		r_xprt->rx_stats.hardway_register_count += size;
550 	}
551 	return true;
552 }
553 
554 /**
555  * xprt_rdma_allocate - allocate transport resources for an RPC
556  * @task: RPC task
557  *
558  * Return values:
559  *        0:	Success; rq_buffer points to RPC buffer to use
560  *   ENOMEM:	Out of memory, call again later
561  *      EIO:	A permanent error occurred, do not retry
562  */
563 static int
564 xprt_rdma_allocate(struct rpc_task *task)
565 {
566 	struct rpc_rqst *rqst = task->tk_rqstp;
567 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(rqst->rq_xprt);
568 	struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
569 	gfp_t flags;
570 
571 	flags = RPCRDMA_DEF_GFP;
572 	if (RPC_IS_SWAPPER(task))
573 		flags = __GFP_MEMALLOC | GFP_NOWAIT | __GFP_NOWARN;
574 
575 	if (!rpcrdma_check_regbuf(r_xprt, req->rl_sendbuf, rqst->rq_callsize,
576 				  flags))
577 		goto out_fail;
578 	if (!rpcrdma_check_regbuf(r_xprt, req->rl_recvbuf, rqst->rq_rcvsize,
579 				  flags))
580 		goto out_fail;
581 
582 	rqst->rq_buffer = rdmab_data(req->rl_sendbuf);
583 	rqst->rq_rbuffer = rdmab_data(req->rl_recvbuf);
584 	trace_xprtrdma_op_allocate(task, req);
585 	return 0;
586 
587 out_fail:
588 	trace_xprtrdma_op_allocate(task, NULL);
589 	return -ENOMEM;
590 }
591 
592 /**
593  * xprt_rdma_free - release resources allocated by xprt_rdma_allocate
594  * @task: RPC task
595  *
596  * Caller guarantees rqst->rq_buffer is non-NULL.
597  */
598 static void
599 xprt_rdma_free(struct rpc_task *task)
600 {
601 	struct rpc_rqst *rqst = task->tk_rqstp;
602 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(rqst->rq_xprt);
603 	struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
604 
605 	trace_xprtrdma_op_free(task, req);
606 
607 	if (!list_empty(&req->rl_registered))
608 		frwr_unmap_sync(r_xprt, req);
609 
610 	/* XXX: If the RPC is completing because of a signal and
611 	 * not because a reply was received, we ought to ensure
612 	 * that the Send completion has fired, so that memory
613 	 * involved with the Send is not still visible to the NIC.
614 	 */
615 }
616 
617 /**
618  * xprt_rdma_send_request - marshal and send an RPC request
619  * @rqst: RPC message in rq_snd_buf
620  *
621  * Caller holds the transport's write lock.
622  *
623  * Returns:
624  *	%0 if the RPC message has been sent
625  *	%-ENOTCONN if the caller should reconnect and call again
626  *	%-EAGAIN if the caller should call again
627  *	%-ENOBUFS if the caller should call again after a delay
628  *	%-EMSGSIZE if encoding ran out of buffer space. The request
629  *		was not sent. Do not try to send this message again.
630  *	%-EIO if an I/O error occurred. The request was not sent.
631  *		Do not try to send this message again.
632  */
633 static int
634 xprt_rdma_send_request(struct rpc_rqst *rqst)
635 {
636 	struct rpc_xprt *xprt = rqst->rq_xprt;
637 	struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
638 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
639 	int rc = 0;
640 
641 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
642 	if (unlikely(!rqst->rq_buffer))
643 		return xprt_rdma_bc_send_reply(rqst);
644 #endif	/* CONFIG_SUNRPC_BACKCHANNEL */
645 
646 	if (!xprt_connected(xprt))
647 		return -ENOTCONN;
648 
649 	if (!xprt_request_get_cong(xprt, rqst))
650 		return -EBADSLT;
651 
652 	rc = rpcrdma_marshal_req(r_xprt, rqst);
653 	if (rc < 0)
654 		goto failed_marshal;
655 
656 	/* Must suppress retransmit to maintain credits */
657 	if (rqst->rq_connect_cookie == xprt->connect_cookie)
658 		goto drop_connection;
659 	rqst->rq_xtime = ktime_get();
660 
661 	if (rpcrdma_post_sends(r_xprt, req))
662 		goto drop_connection;
663 
664 	rqst->rq_xmit_bytes_sent += rqst->rq_snd_buf.len;
665 
666 	/* An RPC with no reply will throw off credit accounting,
667 	 * so drop the connection to reset the credit grant.
668 	 */
669 	if (!rpc_reply_expected(rqst->rq_task))
670 		goto drop_connection;
671 	return 0;
672 
673 failed_marshal:
674 	if (rc != -ENOTCONN)
675 		return rc;
676 drop_connection:
677 	xprt_rdma_close(xprt);
678 	return -ENOTCONN;
679 }
680 
681 void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
682 {
683 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
684 	long idle_time = 0;
685 
686 	if (xprt_connected(xprt))
687 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
688 
689 	seq_puts(seq, "\txprt:\trdma ");
690 	seq_printf(seq, "%u %lu %lu %lu %ld %lu %lu %lu %llu %llu ",
691 		   0,	/* need a local port? */
692 		   xprt->stat.bind_count,
693 		   xprt->stat.connect_count,
694 		   xprt->stat.connect_time / HZ,
695 		   idle_time,
696 		   xprt->stat.sends,
697 		   xprt->stat.recvs,
698 		   xprt->stat.bad_xids,
699 		   xprt->stat.req_u,
700 		   xprt->stat.bklog_u);
701 	seq_printf(seq, "%lu %lu %lu %llu %llu %llu %llu %lu %lu %lu %lu ",
702 		   r_xprt->rx_stats.read_chunk_count,
703 		   r_xprt->rx_stats.write_chunk_count,
704 		   r_xprt->rx_stats.reply_chunk_count,
705 		   r_xprt->rx_stats.total_rdma_request,
706 		   r_xprt->rx_stats.total_rdma_reply,
707 		   r_xprt->rx_stats.pullup_copy_count,
708 		   r_xprt->rx_stats.fixup_copy_count,
709 		   r_xprt->rx_stats.hardway_register_count,
710 		   r_xprt->rx_stats.failed_marshal_count,
711 		   r_xprt->rx_stats.bad_reply_count,
712 		   r_xprt->rx_stats.nomsg_call_count);
713 	seq_printf(seq, "%lu %lu %lu %lu %lu %lu\n",
714 		   r_xprt->rx_stats.mrs_recycled,
715 		   r_xprt->rx_stats.mrs_orphaned,
716 		   r_xprt->rx_stats.mrs_allocated,
717 		   r_xprt->rx_stats.local_inv_needed,
718 		   r_xprt->rx_stats.empty_sendctx_q,
719 		   r_xprt->rx_stats.reply_waits_for_send);
720 }
721 
722 static int
723 xprt_rdma_enable_swap(struct rpc_xprt *xprt)
724 {
725 	return 0;
726 }
727 
728 static void
729 xprt_rdma_disable_swap(struct rpc_xprt *xprt)
730 {
731 }
732 
733 /*
734  * Plumbing for rpc transport switch and kernel module
735  */
736 
737 static const struct rpc_xprt_ops xprt_rdma_procs = {
738 	.reserve_xprt		= xprt_reserve_xprt_cong,
739 	.release_xprt		= xprt_release_xprt_cong, /* sunrpc/xprt.c */
740 	.alloc_slot		= xprt_rdma_alloc_slot,
741 	.free_slot		= xprt_rdma_free_slot,
742 	.release_request	= xprt_release_rqst_cong,       /* ditto */
743 	.wait_for_reply_request	= xprt_wait_for_reply_request_def, /* ditto */
744 	.timer			= xprt_rdma_timer,
745 	.rpcbind		= rpcb_getport_async,	/* sunrpc/rpcb_clnt.c */
746 	.set_port		= xprt_rdma_set_port,
747 	.connect		= xprt_rdma_connect,
748 	.buf_alloc		= xprt_rdma_allocate,
749 	.buf_free		= xprt_rdma_free,
750 	.send_request		= xprt_rdma_send_request,
751 	.close			= xprt_rdma_close,
752 	.destroy		= xprt_rdma_destroy,
753 	.set_connect_timeout	= xprt_rdma_set_connect_timeout,
754 	.print_stats		= xprt_rdma_print_stats,
755 	.enable_swap		= xprt_rdma_enable_swap,
756 	.disable_swap		= xprt_rdma_disable_swap,
757 	.inject_disconnect	= xprt_rdma_inject_disconnect,
758 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
759 	.bc_setup		= xprt_rdma_bc_setup,
760 	.bc_maxpayload		= xprt_rdma_bc_maxpayload,
761 	.bc_num_slots		= xprt_rdma_bc_max_slots,
762 	.bc_free_rqst		= xprt_rdma_bc_free_rqst,
763 	.bc_destroy		= xprt_rdma_bc_destroy,
764 #endif
765 };
766 
767 static struct xprt_class xprt_rdma = {
768 	.list			= LIST_HEAD_INIT(xprt_rdma.list),
769 	.name			= "rdma",
770 	.owner			= THIS_MODULE,
771 	.ident			= XPRT_TRANSPORT_RDMA,
772 	.setup			= xprt_setup_rdma,
773 };
774 
775 void xprt_rdma_cleanup(void)
776 {
777 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
778 	if (sunrpc_table_header) {
779 		unregister_sysctl_table(sunrpc_table_header);
780 		sunrpc_table_header = NULL;
781 	}
782 #endif
783 
784 	xprt_unregister_transport(&xprt_rdma);
785 	xprt_unregister_transport(&xprt_rdma_bc);
786 }
787 
788 int xprt_rdma_init(void)
789 {
790 	int rc;
791 
792 	rc = xprt_register_transport(&xprt_rdma);
793 	if (rc)
794 		return rc;
795 
796 	rc = xprt_register_transport(&xprt_rdma_bc);
797 	if (rc) {
798 		xprt_unregister_transport(&xprt_rdma);
799 		return rc;
800 	}
801 
802 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
803 	if (!sunrpc_table_header)
804 		sunrpc_table_header = register_sysctl_table(sunrpc_table);
805 #endif
806 	return 0;
807 }
808