xref: /openbmc/linux/net/sunrpc/xprtrdma/transport.c (revision d58f75de)
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 (!rc) {
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 	} else {
253 		/* Force a call to xprt_rdma_close to clean up */
254 		spin_lock(&xprt->transport_lock);
255 		set_bit(XPRT_CLOSE_WAIT, &xprt->state);
256 		spin_unlock(&xprt->transport_lock);
257 	}
258 	xprt_wake_pending_tasks(xprt, rc);
259 }
260 
261 /**
262  * xprt_rdma_inject_disconnect - inject a connection fault
263  * @xprt: transport context
264  *
265  * If @xprt is connected, disconnect it to simulate spurious
266  * connection loss. Caller must hold @xprt's send lock to
267  * ensure that data structures and hardware resources are
268  * stable during the rdma_disconnect() call.
269  */
270 static void
271 xprt_rdma_inject_disconnect(struct rpc_xprt *xprt)
272 {
273 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
274 
275 	trace_xprtrdma_op_inject_dsc(r_xprt);
276 	rdma_disconnect(r_xprt->rx_ep->re_id);
277 }
278 
279 /**
280  * xprt_rdma_destroy - Full tear down of transport
281  * @xprt: doomed transport context
282  *
283  * Caller guarantees there will be no more calls to us with
284  * this @xprt.
285  */
286 static void
287 xprt_rdma_destroy(struct rpc_xprt *xprt)
288 {
289 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
290 
291 	cancel_delayed_work_sync(&r_xprt->rx_connect_worker);
292 
293 	rpcrdma_xprt_disconnect(r_xprt);
294 	rpcrdma_buffer_destroy(&r_xprt->rx_buf);
295 
296 	xprt_rdma_free_addresses(xprt);
297 	xprt_free(xprt);
298 
299 	module_put(THIS_MODULE);
300 }
301 
302 /* 60 second timeout, no retries */
303 static const struct rpc_timeout xprt_rdma_default_timeout = {
304 	.to_initval = 60 * HZ,
305 	.to_maxval = 60 * HZ,
306 };
307 
308 /**
309  * xprt_setup_rdma - Set up transport to use RDMA
310  *
311  * @args: rpc transport arguments
312  */
313 static struct rpc_xprt *
314 xprt_setup_rdma(struct xprt_create *args)
315 {
316 	struct rpc_xprt *xprt;
317 	struct rpcrdma_xprt *new_xprt;
318 	struct sockaddr *sap;
319 	int rc;
320 
321 	if (args->addrlen > sizeof(xprt->addr))
322 		return ERR_PTR(-EBADF);
323 
324 	if (!try_module_get(THIS_MODULE))
325 		return ERR_PTR(-EIO);
326 
327 	xprt = xprt_alloc(args->net, sizeof(struct rpcrdma_xprt), 0,
328 			  xprt_rdma_slot_table_entries);
329 	if (!xprt) {
330 		module_put(THIS_MODULE);
331 		return ERR_PTR(-ENOMEM);
332 	}
333 
334 	xprt->timeout = &xprt_rdma_default_timeout;
335 	xprt->connect_timeout = xprt->timeout->to_initval;
336 	xprt->max_reconnect_timeout = xprt->timeout->to_maxval;
337 	xprt->bind_timeout = RPCRDMA_BIND_TO;
338 	xprt->reestablish_timeout = RPCRDMA_INIT_REEST_TO;
339 	xprt->idle_timeout = RPCRDMA_IDLE_DISC_TO;
340 
341 	xprt->resvport = 0;		/* privileged port not needed */
342 	xprt->ops = &xprt_rdma_procs;
343 
344 	/*
345 	 * Set up RDMA-specific connect data.
346 	 */
347 	sap = args->dstaddr;
348 
349 	/* Ensure xprt->addr holds valid server TCP (not RDMA)
350 	 * address, for any side protocols which peek at it */
351 	xprt->prot = IPPROTO_TCP;
352 	xprt->addrlen = args->addrlen;
353 	memcpy(&xprt->addr, sap, xprt->addrlen);
354 
355 	if (rpc_get_port(sap))
356 		xprt_set_bound(xprt);
357 	xprt_rdma_format_addresses(xprt, sap);
358 
359 	new_xprt = rpcx_to_rdmax(xprt);
360 	rc = rpcrdma_buffer_create(new_xprt);
361 	if (rc) {
362 		xprt_rdma_free_addresses(xprt);
363 		xprt_free(xprt);
364 		module_put(THIS_MODULE);
365 		return ERR_PTR(rc);
366 	}
367 
368 	INIT_DELAYED_WORK(&new_xprt->rx_connect_worker,
369 			  xprt_rdma_connect_worker);
370 
371 	xprt->max_payload = RPCRDMA_MAX_DATA_SEGS << PAGE_SHIFT;
372 
373 	return xprt;
374 }
375 
376 /**
377  * xprt_rdma_close - close a transport connection
378  * @xprt: transport context
379  *
380  * Called during autoclose or device removal.
381  *
382  * Caller holds @xprt's send lock to prevent activity on this
383  * transport while the connection is torn down.
384  */
385 void xprt_rdma_close(struct rpc_xprt *xprt)
386 {
387 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
388 
389 	rpcrdma_xprt_disconnect(r_xprt);
390 
391 	xprt->reestablish_timeout = 0;
392 	++xprt->connect_cookie;
393 	xprt_disconnect_done(xprt);
394 }
395 
396 /**
397  * xprt_rdma_set_port - update server port with rpcbind result
398  * @xprt: controlling RPC transport
399  * @port: new port value
400  *
401  * Transport connect status is unchanged.
402  */
403 static void
404 xprt_rdma_set_port(struct rpc_xprt *xprt, u16 port)
405 {
406 	struct sockaddr *sap = (struct sockaddr *)&xprt->addr;
407 	char buf[8];
408 
409 	rpc_set_port(sap, port);
410 
411 	kfree(xprt->address_strings[RPC_DISPLAY_PORT]);
412 	snprintf(buf, sizeof(buf), "%u", port);
413 	xprt->address_strings[RPC_DISPLAY_PORT] = kstrdup(buf, GFP_KERNEL);
414 
415 	kfree(xprt->address_strings[RPC_DISPLAY_HEX_PORT]);
416 	snprintf(buf, sizeof(buf), "%4hx", port);
417 	xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);
418 }
419 
420 /**
421  * xprt_rdma_timer - invoked when an RPC times out
422  * @xprt: controlling RPC transport
423  * @task: RPC task that timed out
424  *
425  * Invoked when the transport is still connected, but an RPC
426  * retransmit timeout occurs.
427  *
428  * Since RDMA connections don't have a keep-alive, forcibly
429  * disconnect and retry to connect. This drives full
430  * detection of the network path, and retransmissions of
431  * all pending RPCs.
432  */
433 static void
434 xprt_rdma_timer(struct rpc_xprt *xprt, struct rpc_task *task)
435 {
436 	xprt_force_disconnect(xprt);
437 }
438 
439 /**
440  * xprt_rdma_set_connect_timeout - set timeouts for establishing a connection
441  * @xprt: controlling transport instance
442  * @connect_timeout: reconnect timeout after client disconnects
443  * @reconnect_timeout: reconnect timeout after server disconnects
444  *
445  */
446 static void xprt_rdma_set_connect_timeout(struct rpc_xprt *xprt,
447 					  unsigned long connect_timeout,
448 					  unsigned long reconnect_timeout)
449 {
450 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
451 
452 	trace_xprtrdma_op_set_cto(r_xprt, connect_timeout, reconnect_timeout);
453 
454 	spin_lock(&xprt->transport_lock);
455 
456 	if (connect_timeout < xprt->connect_timeout) {
457 		struct rpc_timeout to;
458 		unsigned long initval;
459 
460 		to = *xprt->timeout;
461 		initval = connect_timeout;
462 		if (initval < RPCRDMA_INIT_REEST_TO << 1)
463 			initval = RPCRDMA_INIT_REEST_TO << 1;
464 		to.to_initval = initval;
465 		to.to_maxval = initval;
466 		r_xprt->rx_timeout = to;
467 		xprt->timeout = &r_xprt->rx_timeout;
468 		xprt->connect_timeout = connect_timeout;
469 	}
470 
471 	if (reconnect_timeout < xprt->max_reconnect_timeout)
472 		xprt->max_reconnect_timeout = reconnect_timeout;
473 
474 	spin_unlock(&xprt->transport_lock);
475 }
476 
477 /**
478  * xprt_rdma_connect - schedule an attempt to reconnect
479  * @xprt: transport state
480  * @task: RPC scheduler context (unused)
481  *
482  */
483 static void
484 xprt_rdma_connect(struct rpc_xprt *xprt, struct rpc_task *task)
485 {
486 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
487 	struct rpcrdma_ep *ep = r_xprt->rx_ep;
488 	unsigned long delay;
489 
490 	delay = 0;
491 	if (ep && ep->re_connect_status != 0) {
492 		delay = xprt_reconnect_delay(xprt);
493 		xprt_reconnect_backoff(xprt, RPCRDMA_INIT_REEST_TO);
494 	}
495 	trace_xprtrdma_op_connect(r_xprt, delay);
496 	queue_delayed_work(xprtiod_workqueue, &r_xprt->rx_connect_worker,
497 			   delay);
498 }
499 
500 /**
501  * xprt_rdma_alloc_slot - allocate an rpc_rqst
502  * @xprt: controlling RPC transport
503  * @task: RPC task requesting a fresh rpc_rqst
504  *
505  * tk_status values:
506  *	%0 if task->tk_rqstp points to a fresh rpc_rqst
507  *	%-EAGAIN if no rpc_rqst is available; queued on backlog
508  */
509 static void
510 xprt_rdma_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task)
511 {
512 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
513 	struct rpcrdma_req *req;
514 
515 	req = rpcrdma_buffer_get(&r_xprt->rx_buf);
516 	if (!req)
517 		goto out_sleep;
518 	task->tk_rqstp = &req->rl_slot;
519 	task->tk_status = 0;
520 	return;
521 
522 out_sleep:
523 	set_bit(XPRT_CONGESTED, &xprt->state);
524 	rpc_sleep_on(&xprt->backlog, task, NULL);
525 	task->tk_status = -EAGAIN;
526 }
527 
528 /**
529  * xprt_rdma_free_slot - release an rpc_rqst
530  * @xprt: controlling RPC transport
531  * @rqst: rpc_rqst to release
532  *
533  */
534 static void
535 xprt_rdma_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *rqst)
536 {
537 	struct rpcrdma_xprt *r_xprt =
538 		container_of(xprt, struct rpcrdma_xprt, rx_xprt);
539 
540 	memset(rqst, 0, sizeof(*rqst));
541 	rpcrdma_buffer_put(&r_xprt->rx_buf, rpcr_to_rdmar(rqst));
542 	if (unlikely(!rpc_wake_up_next(&xprt->backlog)))
543 		clear_bit(XPRT_CONGESTED, &xprt->state);
544 }
545 
546 static bool rpcrdma_check_regbuf(struct rpcrdma_xprt *r_xprt,
547 				 struct rpcrdma_regbuf *rb, size_t size,
548 				 gfp_t flags)
549 {
550 	if (unlikely(rdmab_length(rb) < size)) {
551 		if (!rpcrdma_regbuf_realloc(rb, size, flags))
552 			return false;
553 		r_xprt->rx_stats.hardway_register_count += size;
554 	}
555 	return true;
556 }
557 
558 /**
559  * xprt_rdma_allocate - allocate transport resources for an RPC
560  * @task: RPC task
561  *
562  * Return values:
563  *        0:	Success; rq_buffer points to RPC buffer to use
564  *   ENOMEM:	Out of memory, call again later
565  *      EIO:	A permanent error occurred, do not retry
566  */
567 static int
568 xprt_rdma_allocate(struct rpc_task *task)
569 {
570 	struct rpc_rqst *rqst = task->tk_rqstp;
571 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(rqst->rq_xprt);
572 	struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
573 	gfp_t flags;
574 
575 	flags = RPCRDMA_DEF_GFP;
576 	if (RPC_IS_SWAPPER(task))
577 		flags = __GFP_MEMALLOC | GFP_NOWAIT | __GFP_NOWARN;
578 
579 	if (!rpcrdma_check_regbuf(r_xprt, req->rl_sendbuf, rqst->rq_callsize,
580 				  flags))
581 		goto out_fail;
582 	if (!rpcrdma_check_regbuf(r_xprt, req->rl_recvbuf, rqst->rq_rcvsize,
583 				  flags))
584 		goto out_fail;
585 
586 	rqst->rq_buffer = rdmab_data(req->rl_sendbuf);
587 	rqst->rq_rbuffer = rdmab_data(req->rl_recvbuf);
588 	return 0;
589 
590 out_fail:
591 	return -ENOMEM;
592 }
593 
594 /**
595  * xprt_rdma_free - release resources allocated by xprt_rdma_allocate
596  * @task: RPC task
597  *
598  * Caller guarantees rqst->rq_buffer is non-NULL.
599  */
600 static void
601 xprt_rdma_free(struct rpc_task *task)
602 {
603 	struct rpc_rqst *rqst = task->tk_rqstp;
604 	struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
605 
606 	if (unlikely(!list_empty(&req->rl_registered))) {
607 		trace_xprtrdma_mrs_zap(task);
608 		frwr_unmap_sync(rpcx_to_rdmax(rqst->rq_xprt), req);
609 	}
610 
611 	/* XXX: If the RPC is completing because of a signal and
612 	 * not because a reply was received, we ought to ensure
613 	 * that the Send completion has fired, so that memory
614 	 * involved with the Send is not still visible to the NIC.
615 	 */
616 }
617 
618 /**
619  * xprt_rdma_send_request - marshal and send an RPC request
620  * @rqst: RPC message in rq_snd_buf
621  *
622  * Caller holds the transport's write lock.
623  *
624  * Returns:
625  *	%0 if the RPC message has been sent
626  *	%-ENOTCONN if the caller should reconnect and call again
627  *	%-EAGAIN if the caller should call again
628  *	%-ENOBUFS if the caller should call again after a delay
629  *	%-EMSGSIZE if encoding ran out of buffer space. The request
630  *		was not sent. Do not try to send this message again.
631  *	%-EIO if an I/O error occurred. The request was not sent.
632  *		Do not try to send this message again.
633  */
634 static int
635 xprt_rdma_send_request(struct rpc_rqst *rqst)
636 {
637 	struct rpc_xprt *xprt = rqst->rq_xprt;
638 	struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
639 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
640 	int rc = 0;
641 
642 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
643 	if (unlikely(!rqst->rq_buffer))
644 		return xprt_rdma_bc_send_reply(rqst);
645 #endif	/* CONFIG_SUNRPC_BACKCHANNEL */
646 
647 	if (!xprt_connected(xprt))
648 		return -ENOTCONN;
649 
650 	if (!xprt_request_get_cong(xprt, rqst))
651 		return -EBADSLT;
652 
653 	rc = rpcrdma_marshal_req(r_xprt, rqst);
654 	if (rc < 0)
655 		goto failed_marshal;
656 
657 	/* Must suppress retransmit to maintain credits */
658 	if (rqst->rq_connect_cookie == xprt->connect_cookie)
659 		goto drop_connection;
660 	rqst->rq_xtime = ktime_get();
661 
662 	if (rpcrdma_post_sends(r_xprt, req))
663 		goto drop_connection;
664 
665 	rqst->rq_xmit_bytes_sent += rqst->rq_snd_buf.len;
666 
667 	/* An RPC with no reply will throw off credit accounting,
668 	 * so drop the connection to reset the credit grant.
669 	 */
670 	if (!rpc_reply_expected(rqst->rq_task))
671 		goto drop_connection;
672 	return 0;
673 
674 failed_marshal:
675 	if (rc != -ENOTCONN)
676 		return rc;
677 drop_connection:
678 	xprt_rdma_close(xprt);
679 	return -ENOTCONN;
680 }
681 
682 void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
683 {
684 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
685 	long idle_time = 0;
686 
687 	if (xprt_connected(xprt))
688 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
689 
690 	seq_puts(seq, "\txprt:\trdma ");
691 	seq_printf(seq, "%u %lu %lu %lu %ld %lu %lu %lu %llu %llu ",
692 		   0,	/* need a local port? */
693 		   xprt->stat.bind_count,
694 		   xprt->stat.connect_count,
695 		   xprt->stat.connect_time / HZ,
696 		   idle_time,
697 		   xprt->stat.sends,
698 		   xprt->stat.recvs,
699 		   xprt->stat.bad_xids,
700 		   xprt->stat.req_u,
701 		   xprt->stat.bklog_u);
702 	seq_printf(seq, "%lu %lu %lu %llu %llu %llu %llu %lu %lu %lu %lu ",
703 		   r_xprt->rx_stats.read_chunk_count,
704 		   r_xprt->rx_stats.write_chunk_count,
705 		   r_xprt->rx_stats.reply_chunk_count,
706 		   r_xprt->rx_stats.total_rdma_request,
707 		   r_xprt->rx_stats.total_rdma_reply,
708 		   r_xprt->rx_stats.pullup_copy_count,
709 		   r_xprt->rx_stats.fixup_copy_count,
710 		   r_xprt->rx_stats.hardway_register_count,
711 		   r_xprt->rx_stats.failed_marshal_count,
712 		   r_xprt->rx_stats.bad_reply_count,
713 		   r_xprt->rx_stats.nomsg_call_count);
714 	seq_printf(seq, "%lu %lu %lu %lu %lu %lu\n",
715 		   r_xprt->rx_stats.mrs_recycled,
716 		   r_xprt->rx_stats.mrs_orphaned,
717 		   r_xprt->rx_stats.mrs_allocated,
718 		   r_xprt->rx_stats.local_inv_needed,
719 		   r_xprt->rx_stats.empty_sendctx_q,
720 		   r_xprt->rx_stats.reply_waits_for_send);
721 }
722 
723 static int
724 xprt_rdma_enable_swap(struct rpc_xprt *xprt)
725 {
726 	return 0;
727 }
728 
729 static void
730 xprt_rdma_disable_swap(struct rpc_xprt *xprt)
731 {
732 }
733 
734 /*
735  * Plumbing for rpc transport switch and kernel module
736  */
737 
738 static const struct rpc_xprt_ops xprt_rdma_procs = {
739 	.reserve_xprt		= xprt_reserve_xprt_cong,
740 	.release_xprt		= xprt_release_xprt_cong, /* sunrpc/xprt.c */
741 	.alloc_slot		= xprt_rdma_alloc_slot,
742 	.free_slot		= xprt_rdma_free_slot,
743 	.release_request	= xprt_release_rqst_cong,       /* ditto */
744 	.wait_for_reply_request	= xprt_wait_for_reply_request_def, /* ditto */
745 	.timer			= xprt_rdma_timer,
746 	.rpcbind		= rpcb_getport_async,	/* sunrpc/rpcb_clnt.c */
747 	.set_port		= xprt_rdma_set_port,
748 	.connect		= xprt_rdma_connect,
749 	.buf_alloc		= xprt_rdma_allocate,
750 	.buf_free		= xprt_rdma_free,
751 	.send_request		= xprt_rdma_send_request,
752 	.close			= xprt_rdma_close,
753 	.destroy		= xprt_rdma_destroy,
754 	.set_connect_timeout	= xprt_rdma_set_connect_timeout,
755 	.print_stats		= xprt_rdma_print_stats,
756 	.enable_swap		= xprt_rdma_enable_swap,
757 	.disable_swap		= xprt_rdma_disable_swap,
758 	.inject_disconnect	= xprt_rdma_inject_disconnect,
759 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
760 	.bc_setup		= xprt_rdma_bc_setup,
761 	.bc_maxpayload		= xprt_rdma_bc_maxpayload,
762 	.bc_num_slots		= xprt_rdma_bc_max_slots,
763 	.bc_free_rqst		= xprt_rdma_bc_free_rqst,
764 	.bc_destroy		= xprt_rdma_bc_destroy,
765 #endif
766 };
767 
768 static struct xprt_class xprt_rdma = {
769 	.list			= LIST_HEAD_INIT(xprt_rdma.list),
770 	.name			= "rdma",
771 	.owner			= THIS_MODULE,
772 	.ident			= XPRT_TRANSPORT_RDMA,
773 	.setup			= xprt_setup_rdma,
774 	.netid			= { "rdma", "rdma6", "" },
775 };
776 
777 void xprt_rdma_cleanup(void)
778 {
779 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
780 	if (sunrpc_table_header) {
781 		unregister_sysctl_table(sunrpc_table_header);
782 		sunrpc_table_header = NULL;
783 	}
784 #endif
785 
786 	xprt_unregister_transport(&xprt_rdma);
787 	xprt_unregister_transport(&xprt_rdma_bc);
788 }
789 
790 int xprt_rdma_init(void)
791 {
792 	int rc;
793 
794 	rc = xprt_register_transport(&xprt_rdma);
795 	if (rc)
796 		return rc;
797 
798 	rc = xprt_register_transport(&xprt_rdma_bc);
799 	if (rc) {
800 		xprt_unregister_transport(&xprt_rdma);
801 		return rc;
802 	}
803 
804 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
805 	if (!sunrpc_table_header)
806 		sunrpc_table_header = register_sysctl_table(sunrpc_table);
807 #endif
808 	return 0;
809 }
810