xref: /openbmc/linux/net/sunrpc/xprtrdma/transport.c (revision 98ddec80)
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 static 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 zero;
84 static unsigned int max_padding = PAGE_SIZE;
85 static unsigned int min_memreg = RPCRDMA_BOUNCEBUFFERS;
86 static unsigned int max_memreg = RPCRDMA_LAST - 1;
87 static unsigned int dummy;
88 
89 static struct ctl_table_header *sunrpc_table_header;
90 
91 static struct ctl_table xr_tunables_table[] = {
92 	{
93 		.procname	= "rdma_slot_table_entries",
94 		.data		= &xprt_rdma_slot_table_entries,
95 		.maxlen		= sizeof(unsigned int),
96 		.mode		= 0644,
97 		.proc_handler	= proc_dointvec_minmax,
98 		.extra1		= &min_slot_table_size,
99 		.extra2		= &max_slot_table_size
100 	},
101 	{
102 		.procname	= "rdma_max_inline_read",
103 		.data		= &xprt_rdma_max_inline_read,
104 		.maxlen		= sizeof(unsigned int),
105 		.mode		= 0644,
106 		.proc_handler	= proc_dointvec_minmax,
107 		.extra1		= &min_inline_size,
108 		.extra2		= &max_inline_size,
109 	},
110 	{
111 		.procname	= "rdma_max_inline_write",
112 		.data		= &xprt_rdma_max_inline_write,
113 		.maxlen		= sizeof(unsigned int),
114 		.mode		= 0644,
115 		.proc_handler	= proc_dointvec_minmax,
116 		.extra1		= &min_inline_size,
117 		.extra2		= &max_inline_size,
118 	},
119 	{
120 		.procname	= "rdma_inline_write_padding",
121 		.data		= &dummy,
122 		.maxlen		= sizeof(unsigned int),
123 		.mode		= 0644,
124 		.proc_handler	= proc_dointvec_minmax,
125 		.extra1		= &zero,
126 		.extra2		= &max_padding,
127 	},
128 	{
129 		.procname	= "rdma_memreg_strategy",
130 		.data		= &xprt_rdma_memreg_strategy,
131 		.maxlen		= sizeof(unsigned int),
132 		.mode		= 0644,
133 		.proc_handler	= proc_dointvec_minmax,
134 		.extra1		= &min_memreg,
135 		.extra2		= &max_memreg,
136 	},
137 	{
138 		.procname	= "rdma_pad_optimize",
139 		.data		= &xprt_rdma_pad_optimize,
140 		.maxlen		= sizeof(unsigned int),
141 		.mode		= 0644,
142 		.proc_handler	= proc_dointvec,
143 	},
144 	{ },
145 };
146 
147 static struct ctl_table sunrpc_table[] = {
148 	{
149 		.procname	= "sunrpc",
150 		.mode		= 0555,
151 		.child		= xr_tunables_table
152 	},
153 	{ },
154 };
155 
156 #endif
157 
158 static const struct rpc_xprt_ops xprt_rdma_procs;
159 
160 static void
161 xprt_rdma_format_addresses4(struct rpc_xprt *xprt, struct sockaddr *sap)
162 {
163 	struct sockaddr_in *sin = (struct sockaddr_in *)sap;
164 	char buf[20];
165 
166 	snprintf(buf, sizeof(buf), "%08x", ntohl(sin->sin_addr.s_addr));
167 	xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = kstrdup(buf, GFP_KERNEL);
168 
169 	xprt->address_strings[RPC_DISPLAY_NETID] = RPCBIND_NETID_RDMA;
170 }
171 
172 static void
173 xprt_rdma_format_addresses6(struct rpc_xprt *xprt, struct sockaddr *sap)
174 {
175 	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
176 	char buf[40];
177 
178 	snprintf(buf, sizeof(buf), "%pi6", &sin6->sin6_addr);
179 	xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = kstrdup(buf, GFP_KERNEL);
180 
181 	xprt->address_strings[RPC_DISPLAY_NETID] = RPCBIND_NETID_RDMA6;
182 }
183 
184 void
185 xprt_rdma_format_addresses(struct rpc_xprt *xprt, struct sockaddr *sap)
186 {
187 	char buf[128];
188 
189 	switch (sap->sa_family) {
190 	case AF_INET:
191 		xprt_rdma_format_addresses4(xprt, sap);
192 		break;
193 	case AF_INET6:
194 		xprt_rdma_format_addresses6(xprt, sap);
195 		break;
196 	default:
197 		pr_err("rpcrdma: Unrecognized address family\n");
198 		return;
199 	}
200 
201 	(void)rpc_ntop(sap, buf, sizeof(buf));
202 	xprt->address_strings[RPC_DISPLAY_ADDR] = kstrdup(buf, GFP_KERNEL);
203 
204 	snprintf(buf, sizeof(buf), "%u", rpc_get_port(sap));
205 	xprt->address_strings[RPC_DISPLAY_PORT] = kstrdup(buf, GFP_KERNEL);
206 
207 	snprintf(buf, sizeof(buf), "%4hx", rpc_get_port(sap));
208 	xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);
209 
210 	xprt->address_strings[RPC_DISPLAY_PROTO] = "rdma";
211 }
212 
213 void
214 xprt_rdma_free_addresses(struct rpc_xprt *xprt)
215 {
216 	unsigned int i;
217 
218 	for (i = 0; i < RPC_DISPLAY_MAX; i++)
219 		switch (i) {
220 		case RPC_DISPLAY_PROTO:
221 		case RPC_DISPLAY_NETID:
222 			continue;
223 		default:
224 			kfree(xprt->address_strings[i]);
225 		}
226 }
227 
228 void
229 rpcrdma_conn_func(struct rpcrdma_ep *ep)
230 {
231 	schedule_delayed_work(&ep->rep_connect_worker, 0);
232 }
233 
234 void
235 rpcrdma_connect_worker(struct work_struct *work)
236 {
237 	struct rpcrdma_ep *ep =
238 		container_of(work, struct rpcrdma_ep, rep_connect_worker.work);
239 	struct rpcrdma_xprt *r_xprt =
240 		container_of(ep, struct rpcrdma_xprt, rx_ep);
241 	struct rpc_xprt *xprt = &r_xprt->rx_xprt;
242 
243 	spin_lock_bh(&xprt->transport_lock);
244 	if (ep->rep_connected > 0) {
245 		if (!xprt_test_and_set_connected(xprt))
246 			xprt_wake_pending_tasks(xprt, 0);
247 	} else {
248 		if (xprt_test_and_clear_connected(xprt))
249 			xprt_wake_pending_tasks(xprt, -ENOTCONN);
250 	}
251 	spin_unlock_bh(&xprt->transport_lock);
252 }
253 
254 static void
255 xprt_rdma_connect_worker(struct work_struct *work)
256 {
257 	struct rpcrdma_xprt *r_xprt = container_of(work, struct rpcrdma_xprt,
258 						   rx_connect_worker.work);
259 	struct rpc_xprt *xprt = &r_xprt->rx_xprt;
260 	int rc = 0;
261 
262 	xprt_clear_connected(xprt);
263 
264 	rc = rpcrdma_ep_connect(&r_xprt->rx_ep, &r_xprt->rx_ia);
265 	if (rc)
266 		xprt_wake_pending_tasks(xprt, rc);
267 
268 	xprt_clear_connecting(xprt);
269 }
270 
271 static void
272 xprt_rdma_inject_disconnect(struct rpc_xprt *xprt)
273 {
274 	struct rpcrdma_xprt *r_xprt = container_of(xprt, struct rpcrdma_xprt,
275 						   rx_xprt);
276 
277 	trace_xprtrdma_inject_dsc(r_xprt);
278 	rdma_disconnect(r_xprt->rx_ia.ri_id);
279 }
280 
281 /*
282  * xprt_rdma_destroy
283  *
284  * Destroy the xprt.
285  * Free all memory associated with the object, including its own.
286  * NOTE: none of the *destroy methods free memory for their top-level
287  * objects, even though they may have allocated it (they do free
288  * private memory). It's up to the caller to handle it. In this
289  * case (RDMA transport), all structure memory is inlined with the
290  * struct rpcrdma_xprt.
291  */
292 static void
293 xprt_rdma_destroy(struct rpc_xprt *xprt)
294 {
295 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
296 
297 	trace_xprtrdma_destroy(r_xprt);
298 
299 	cancel_delayed_work_sync(&r_xprt->rx_connect_worker);
300 
301 	xprt_clear_connected(xprt);
302 
303 	rpcrdma_ep_destroy(&r_xprt->rx_ep, &r_xprt->rx_ia);
304 	rpcrdma_buffer_destroy(&r_xprt->rx_buf);
305 	rpcrdma_ia_close(&r_xprt->rx_ia);
306 
307 	xprt_rdma_free_addresses(xprt);
308 	xprt_free(xprt);
309 
310 	module_put(THIS_MODULE);
311 }
312 
313 static const struct rpc_timeout xprt_rdma_default_timeout = {
314 	.to_initval = 60 * HZ,
315 	.to_maxval = 60 * HZ,
316 };
317 
318 /**
319  * xprt_setup_rdma - Set up transport to use RDMA
320  *
321  * @args: rpc transport arguments
322  */
323 static struct rpc_xprt *
324 xprt_setup_rdma(struct xprt_create *args)
325 {
326 	struct rpcrdma_create_data_internal cdata;
327 	struct rpc_xprt *xprt;
328 	struct rpcrdma_xprt *new_xprt;
329 	struct rpcrdma_ep *new_ep;
330 	struct sockaddr *sap;
331 	int rc;
332 
333 	if (args->addrlen > sizeof(xprt->addr)) {
334 		dprintk("RPC:       %s: address too large\n", __func__);
335 		return ERR_PTR(-EBADF);
336 	}
337 
338 	xprt = xprt_alloc(args->net, sizeof(struct rpcrdma_xprt), 0, 0);
339 	if (xprt == NULL) {
340 		dprintk("RPC:       %s: couldn't allocate rpcrdma_xprt\n",
341 			__func__);
342 		return ERR_PTR(-ENOMEM);
343 	}
344 
345 	/* 60 second timeout, no retries */
346 	xprt->timeout = &xprt_rdma_default_timeout;
347 	xprt->bind_timeout = RPCRDMA_BIND_TO;
348 	xprt->reestablish_timeout = RPCRDMA_INIT_REEST_TO;
349 	xprt->idle_timeout = RPCRDMA_IDLE_DISC_TO;
350 
351 	xprt->resvport = 0;		/* privileged port not needed */
352 	xprt->tsh_size = 0;		/* RPC-RDMA handles framing */
353 	xprt->ops = &xprt_rdma_procs;
354 
355 	/*
356 	 * Set up RDMA-specific connect data.
357 	 */
358 	sap = args->dstaddr;
359 
360 	/* Ensure xprt->addr holds valid server TCP (not RDMA)
361 	 * address, for any side protocols which peek at it */
362 	xprt->prot = IPPROTO_TCP;
363 	xprt->addrlen = args->addrlen;
364 	memcpy(&xprt->addr, sap, xprt->addrlen);
365 
366 	if (rpc_get_port(sap))
367 		xprt_set_bound(xprt);
368 	xprt_rdma_format_addresses(xprt, sap);
369 
370 	cdata.max_requests = xprt_rdma_slot_table_entries;
371 
372 	cdata.rsize = RPCRDMA_MAX_SEGS * PAGE_SIZE; /* RDMA write max */
373 	cdata.wsize = RPCRDMA_MAX_SEGS * PAGE_SIZE; /* RDMA read max */
374 
375 	cdata.inline_wsize = xprt_rdma_max_inline_write;
376 	if (cdata.inline_wsize > cdata.wsize)
377 		cdata.inline_wsize = cdata.wsize;
378 
379 	cdata.inline_rsize = xprt_rdma_max_inline_read;
380 	if (cdata.inline_rsize > cdata.rsize)
381 		cdata.inline_rsize = cdata.rsize;
382 
383 	/*
384 	 * Create new transport instance, which includes initialized
385 	 *  o ia
386 	 *  o endpoint
387 	 *  o buffers
388 	 */
389 
390 	new_xprt = rpcx_to_rdmax(xprt);
391 
392 	rc = rpcrdma_ia_open(new_xprt);
393 	if (rc)
394 		goto out1;
395 
396 	/*
397 	 * initialize and create ep
398 	 */
399 	new_xprt->rx_data = cdata;
400 	new_ep = &new_xprt->rx_ep;
401 
402 	rc = rpcrdma_ep_create(&new_xprt->rx_ep,
403 				&new_xprt->rx_ia, &new_xprt->rx_data);
404 	if (rc)
405 		goto out2;
406 
407 	rc = rpcrdma_buffer_create(new_xprt);
408 	if (rc)
409 		goto out3;
410 
411 	INIT_DELAYED_WORK(&new_xprt->rx_connect_worker,
412 			  xprt_rdma_connect_worker);
413 
414 	xprt->max_payload = new_xprt->rx_ia.ri_ops->ro_maxpages(new_xprt);
415 	if (xprt->max_payload == 0)
416 		goto out4;
417 	xprt->max_payload <<= PAGE_SHIFT;
418 	dprintk("RPC:       %s: transport data payload maximum: %zu bytes\n",
419 		__func__, xprt->max_payload);
420 
421 	if (!try_module_get(THIS_MODULE))
422 		goto out4;
423 
424 	dprintk("RPC:       %s: %s:%s\n", __func__,
425 		xprt->address_strings[RPC_DISPLAY_ADDR],
426 		xprt->address_strings[RPC_DISPLAY_PORT]);
427 	trace_xprtrdma_create(new_xprt);
428 	return xprt;
429 
430 out4:
431 	rpcrdma_buffer_destroy(&new_xprt->rx_buf);
432 	rc = -ENODEV;
433 out3:
434 	rpcrdma_ep_destroy(new_ep, &new_xprt->rx_ia);
435 out2:
436 	rpcrdma_ia_close(&new_xprt->rx_ia);
437 out1:
438 	trace_xprtrdma_destroy(new_xprt);
439 	xprt_rdma_free_addresses(xprt);
440 	xprt_free(xprt);
441 	return ERR_PTR(rc);
442 }
443 
444 /**
445  * xprt_rdma_close - Close down RDMA connection
446  * @xprt: generic transport to be closed
447  *
448  * Called during transport shutdown reconnect, or device
449  * removal. Caller holds the transport's write lock.
450  */
451 static void
452 xprt_rdma_close(struct rpc_xprt *xprt)
453 {
454 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
455 	struct rpcrdma_ep *ep = &r_xprt->rx_ep;
456 	struct rpcrdma_ia *ia = &r_xprt->rx_ia;
457 
458 	dprintk("RPC:       %s: closing xprt %p\n", __func__, xprt);
459 
460 	if (test_and_clear_bit(RPCRDMA_IAF_REMOVING, &ia->ri_flags)) {
461 		xprt_clear_connected(xprt);
462 		rpcrdma_ia_remove(ia);
463 		return;
464 	}
465 	if (ep->rep_connected == -ENODEV)
466 		return;
467 	if (ep->rep_connected > 0)
468 		xprt->reestablish_timeout = 0;
469 	xprt_disconnect_done(xprt);
470 	rpcrdma_ep_disconnect(ep, ia);
471 }
472 
473 /**
474  * xprt_rdma_set_port - update server port with rpcbind result
475  * @xprt: controlling RPC transport
476  * @port: new port value
477  *
478  * Transport connect status is unchanged.
479  */
480 static void
481 xprt_rdma_set_port(struct rpc_xprt *xprt, u16 port)
482 {
483 	struct sockaddr *sap = (struct sockaddr *)&xprt->addr;
484 	char buf[8];
485 
486 	dprintk("RPC:       %s: setting port for xprt %p (%s:%s) to %u\n",
487 		__func__, xprt,
488 		xprt->address_strings[RPC_DISPLAY_ADDR],
489 		xprt->address_strings[RPC_DISPLAY_PORT],
490 		port);
491 
492 	rpc_set_port(sap, port);
493 
494 	kfree(xprt->address_strings[RPC_DISPLAY_PORT]);
495 	snprintf(buf, sizeof(buf), "%u", port);
496 	xprt->address_strings[RPC_DISPLAY_PORT] = kstrdup(buf, GFP_KERNEL);
497 
498 	kfree(xprt->address_strings[RPC_DISPLAY_HEX_PORT]);
499 	snprintf(buf, sizeof(buf), "%4hx", port);
500 	xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);
501 }
502 
503 /**
504  * xprt_rdma_timer - invoked when an RPC times out
505  * @xprt: controlling RPC transport
506  * @task: RPC task that timed out
507  *
508  * Invoked when the transport is still connected, but an RPC
509  * retransmit timeout occurs.
510  *
511  * Since RDMA connections don't have a keep-alive, forcibly
512  * disconnect and retry to connect. This drives full
513  * detection of the network path, and retransmissions of
514  * all pending RPCs.
515  */
516 static void
517 xprt_rdma_timer(struct rpc_xprt *xprt, struct rpc_task *task)
518 {
519 	xprt_force_disconnect(xprt);
520 }
521 
522 static void
523 xprt_rdma_connect(struct rpc_xprt *xprt, struct rpc_task *task)
524 {
525 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
526 
527 	if (r_xprt->rx_ep.rep_connected != 0) {
528 		/* Reconnect */
529 		schedule_delayed_work(&r_xprt->rx_connect_worker,
530 				      xprt->reestablish_timeout);
531 		xprt->reestablish_timeout <<= 1;
532 		if (xprt->reestablish_timeout > RPCRDMA_MAX_REEST_TO)
533 			xprt->reestablish_timeout = RPCRDMA_MAX_REEST_TO;
534 		else if (xprt->reestablish_timeout < RPCRDMA_INIT_REEST_TO)
535 			xprt->reestablish_timeout = RPCRDMA_INIT_REEST_TO;
536 	} else {
537 		schedule_delayed_work(&r_xprt->rx_connect_worker, 0);
538 		if (!RPC_IS_ASYNC(task))
539 			flush_delayed_work(&r_xprt->rx_connect_worker);
540 	}
541 }
542 
543 /**
544  * xprt_rdma_alloc_slot - allocate an rpc_rqst
545  * @xprt: controlling RPC transport
546  * @task: RPC task requesting a fresh rpc_rqst
547  *
548  * tk_status values:
549  *	%0 if task->tk_rqstp points to a fresh rpc_rqst
550  *	%-EAGAIN if no rpc_rqst is available; queued on backlog
551  */
552 static void
553 xprt_rdma_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task)
554 {
555 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
556 	struct rpcrdma_req *req;
557 
558 	req = rpcrdma_buffer_get(&r_xprt->rx_buf);
559 	if (!req)
560 		goto out_sleep;
561 	task->tk_rqstp = &req->rl_slot;
562 	task->tk_status = 0;
563 	return;
564 
565 out_sleep:
566 	rpc_sleep_on(&xprt->backlog, task, NULL);
567 	task->tk_status = -EAGAIN;
568 }
569 
570 /**
571  * xprt_rdma_free_slot - release an rpc_rqst
572  * @xprt: controlling RPC transport
573  * @rqst: rpc_rqst to release
574  *
575  */
576 static void
577 xprt_rdma_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *rqst)
578 {
579 	memset(rqst, 0, sizeof(*rqst));
580 	rpcrdma_buffer_put(rpcr_to_rdmar(rqst));
581 	rpc_wake_up_next(&xprt->backlog);
582 }
583 
584 static bool
585 rpcrdma_get_sendbuf(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req,
586 		    size_t size, gfp_t flags)
587 {
588 	struct rpcrdma_regbuf *rb;
589 
590 	if (req->rl_sendbuf && rdmab_length(req->rl_sendbuf) >= size)
591 		return true;
592 
593 	rb = rpcrdma_alloc_regbuf(size, DMA_TO_DEVICE, flags);
594 	if (IS_ERR(rb))
595 		return false;
596 
597 	rpcrdma_free_regbuf(req->rl_sendbuf);
598 	r_xprt->rx_stats.hardway_register_count += size;
599 	req->rl_sendbuf = rb;
600 	return true;
601 }
602 
603 /* The rq_rcv_buf is used only if a Reply chunk is necessary.
604  * The decision to use a Reply chunk is made later in
605  * rpcrdma_marshal_req. This buffer is registered at that time.
606  *
607  * Otherwise, the associated RPC Reply arrives in a separate
608  * Receive buffer, arbitrarily chosen by the HCA. The buffer
609  * allocated here for the RPC Reply is not utilized in that
610  * case. See rpcrdma_inline_fixup.
611  *
612  * A regbuf is used here to remember the buffer size.
613  */
614 static bool
615 rpcrdma_get_recvbuf(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req,
616 		    size_t size, gfp_t flags)
617 {
618 	struct rpcrdma_regbuf *rb;
619 
620 	if (req->rl_recvbuf && rdmab_length(req->rl_recvbuf) >= size)
621 		return true;
622 
623 	rb = rpcrdma_alloc_regbuf(size, DMA_NONE, flags);
624 	if (IS_ERR(rb))
625 		return false;
626 
627 	rpcrdma_free_regbuf(req->rl_recvbuf);
628 	r_xprt->rx_stats.hardway_register_count += size;
629 	req->rl_recvbuf = rb;
630 	return true;
631 }
632 
633 /**
634  * xprt_rdma_allocate - allocate transport resources for an RPC
635  * @task: RPC task
636  *
637  * Return values:
638  *        0:	Success; rq_buffer points to RPC buffer to use
639  *   ENOMEM:	Out of memory, call again later
640  *      EIO:	A permanent error occurred, do not retry
641  *
642  * The RDMA allocate/free functions need the task structure as a place
643  * to hide the struct rpcrdma_req, which is necessary for the actual
644  * send/recv sequence.
645  *
646  * xprt_rdma_allocate provides buffers that are already mapped for
647  * DMA, and a local DMA lkey is provided for each.
648  */
649 static int
650 xprt_rdma_allocate(struct rpc_task *task)
651 {
652 	struct rpc_rqst *rqst = task->tk_rqstp;
653 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(rqst->rq_xprt);
654 	struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
655 	gfp_t flags;
656 
657 	flags = RPCRDMA_DEF_GFP;
658 	if (RPC_IS_SWAPPER(task))
659 		flags = __GFP_MEMALLOC | GFP_NOWAIT | __GFP_NOWARN;
660 
661 	if (!rpcrdma_get_sendbuf(r_xprt, req, rqst->rq_callsize, flags))
662 		goto out_fail;
663 	if (!rpcrdma_get_recvbuf(r_xprt, req, rqst->rq_rcvsize, flags))
664 		goto out_fail;
665 
666 	rqst->rq_buffer = req->rl_sendbuf->rg_base;
667 	rqst->rq_rbuffer = req->rl_recvbuf->rg_base;
668 	trace_xprtrdma_allocate(task, req);
669 	return 0;
670 
671 out_fail:
672 	trace_xprtrdma_allocate(task, NULL);
673 	return -ENOMEM;
674 }
675 
676 /**
677  * xprt_rdma_free - release resources allocated by xprt_rdma_allocate
678  * @task: RPC task
679  *
680  * Caller guarantees rqst->rq_buffer is non-NULL.
681  */
682 static void
683 xprt_rdma_free(struct rpc_task *task)
684 {
685 	struct rpc_rqst *rqst = task->tk_rqstp;
686 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(rqst->rq_xprt);
687 	struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
688 
689 	if (test_bit(RPCRDMA_REQ_F_PENDING, &req->rl_flags))
690 		rpcrdma_release_rqst(r_xprt, req);
691 	trace_xprtrdma_rpc_done(task, req);
692 }
693 
694 /**
695  * xprt_rdma_send_request - marshal and send an RPC request
696  * @task: RPC task with an RPC message in rq_snd_buf
697  *
698  * Caller holds the transport's write lock.
699  *
700  * Returns:
701  *	%0 if the RPC message has been sent
702  *	%-ENOTCONN if the caller should reconnect and call again
703  *	%-EAGAIN if the caller should call again
704  *	%-ENOBUFS if the caller should call again after a delay
705  *	%-EIO if a permanent error occurred and the request was not
706  *		sent. Do not try to send this message again.
707  */
708 static int
709 xprt_rdma_send_request(struct rpc_task *task)
710 {
711 	struct rpc_rqst *rqst = task->tk_rqstp;
712 	struct rpc_xprt *xprt = rqst->rq_xprt;
713 	struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
714 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
715 	int rc = 0;
716 
717 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
718 	if (unlikely(!rqst->rq_buffer))
719 		return xprt_rdma_bc_send_reply(rqst);
720 #endif	/* CONFIG_SUNRPC_BACKCHANNEL */
721 
722 	if (!xprt_connected(xprt))
723 		goto drop_connection;
724 
725 	rc = rpcrdma_marshal_req(r_xprt, rqst);
726 	if (rc < 0)
727 		goto failed_marshal;
728 
729 	/* Must suppress retransmit to maintain credits */
730 	if (rqst->rq_connect_cookie == xprt->connect_cookie)
731 		goto drop_connection;
732 	rqst->rq_xtime = ktime_get();
733 
734 	__set_bit(RPCRDMA_REQ_F_PENDING, &req->rl_flags);
735 	if (rpcrdma_ep_post(&r_xprt->rx_ia, &r_xprt->rx_ep, req))
736 		goto drop_connection;
737 
738 	rqst->rq_xmit_bytes_sent += rqst->rq_snd_buf.len;
739 	rqst->rq_bytes_sent = 0;
740 
741 	/* An RPC with no reply will throw off credit accounting,
742 	 * so drop the connection to reset the credit grant.
743 	 */
744 	if (!rpc_reply_expected(task))
745 		goto drop_connection;
746 	return 0;
747 
748 failed_marshal:
749 	if (rc != -ENOTCONN)
750 		return rc;
751 drop_connection:
752 	xprt_disconnect_done(xprt);
753 	return -ENOTCONN;	/* implies disconnect */
754 }
755 
756 void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
757 {
758 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
759 	long idle_time = 0;
760 
761 	if (xprt_connected(xprt))
762 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
763 
764 	seq_puts(seq, "\txprt:\trdma ");
765 	seq_printf(seq, "%u %lu %lu %lu %ld %lu %lu %lu %llu %llu ",
766 		   0,	/* need a local port? */
767 		   xprt->stat.bind_count,
768 		   xprt->stat.connect_count,
769 		   xprt->stat.connect_time,
770 		   idle_time,
771 		   xprt->stat.sends,
772 		   xprt->stat.recvs,
773 		   xprt->stat.bad_xids,
774 		   xprt->stat.req_u,
775 		   xprt->stat.bklog_u);
776 	seq_printf(seq, "%lu %lu %lu %llu %llu %llu %llu %lu %lu %lu %lu ",
777 		   r_xprt->rx_stats.read_chunk_count,
778 		   r_xprt->rx_stats.write_chunk_count,
779 		   r_xprt->rx_stats.reply_chunk_count,
780 		   r_xprt->rx_stats.total_rdma_request,
781 		   r_xprt->rx_stats.total_rdma_reply,
782 		   r_xprt->rx_stats.pullup_copy_count,
783 		   r_xprt->rx_stats.fixup_copy_count,
784 		   r_xprt->rx_stats.hardway_register_count,
785 		   r_xprt->rx_stats.failed_marshal_count,
786 		   r_xprt->rx_stats.bad_reply_count,
787 		   r_xprt->rx_stats.nomsg_call_count);
788 	seq_printf(seq, "%lu %lu %lu %lu %lu %lu\n",
789 		   r_xprt->rx_stats.mrs_recovered,
790 		   r_xprt->rx_stats.mrs_orphaned,
791 		   r_xprt->rx_stats.mrs_allocated,
792 		   r_xprt->rx_stats.local_inv_needed,
793 		   r_xprt->rx_stats.empty_sendctx_q,
794 		   r_xprt->rx_stats.reply_waits_for_send);
795 }
796 
797 static int
798 xprt_rdma_enable_swap(struct rpc_xprt *xprt)
799 {
800 	return 0;
801 }
802 
803 static void
804 xprt_rdma_disable_swap(struct rpc_xprt *xprt)
805 {
806 }
807 
808 /*
809  * Plumbing for rpc transport switch and kernel module
810  */
811 
812 static const struct rpc_xprt_ops xprt_rdma_procs = {
813 	.reserve_xprt		= xprt_reserve_xprt_cong,
814 	.release_xprt		= xprt_release_xprt_cong, /* sunrpc/xprt.c */
815 	.alloc_slot		= xprt_rdma_alloc_slot,
816 	.free_slot		= xprt_rdma_free_slot,
817 	.release_request	= xprt_release_rqst_cong,       /* ditto */
818 	.set_retrans_timeout	= xprt_set_retrans_timeout_def, /* ditto */
819 	.timer			= xprt_rdma_timer,
820 	.rpcbind		= rpcb_getport_async,	/* sunrpc/rpcb_clnt.c */
821 	.set_port		= xprt_rdma_set_port,
822 	.connect		= xprt_rdma_connect,
823 	.buf_alloc		= xprt_rdma_allocate,
824 	.buf_free		= xprt_rdma_free,
825 	.send_request		= xprt_rdma_send_request,
826 	.close			= xprt_rdma_close,
827 	.destroy		= xprt_rdma_destroy,
828 	.print_stats		= xprt_rdma_print_stats,
829 	.enable_swap		= xprt_rdma_enable_swap,
830 	.disable_swap		= xprt_rdma_disable_swap,
831 	.inject_disconnect	= xprt_rdma_inject_disconnect,
832 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
833 	.bc_setup		= xprt_rdma_bc_setup,
834 	.bc_up			= xprt_rdma_bc_up,
835 	.bc_maxpayload		= xprt_rdma_bc_maxpayload,
836 	.bc_free_rqst		= xprt_rdma_bc_free_rqst,
837 	.bc_destroy		= xprt_rdma_bc_destroy,
838 #endif
839 };
840 
841 static struct xprt_class xprt_rdma = {
842 	.list			= LIST_HEAD_INIT(xprt_rdma.list),
843 	.name			= "rdma",
844 	.owner			= THIS_MODULE,
845 	.ident			= XPRT_TRANSPORT_RDMA,
846 	.setup			= xprt_setup_rdma,
847 };
848 
849 void xprt_rdma_cleanup(void)
850 {
851 	int rc;
852 
853 	dprintk("RPCRDMA Module Removed, deregister RPC RDMA transport\n");
854 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
855 	if (sunrpc_table_header) {
856 		unregister_sysctl_table(sunrpc_table_header);
857 		sunrpc_table_header = NULL;
858 	}
859 #endif
860 	rc = xprt_unregister_transport(&xprt_rdma);
861 	if (rc)
862 		dprintk("RPC:       %s: xprt_unregister returned %i\n",
863 			__func__, rc);
864 
865 	rpcrdma_destroy_wq();
866 
867 	rc = xprt_unregister_transport(&xprt_rdma_bc);
868 	if (rc)
869 		dprintk("RPC:       %s: xprt_unregister(bc) returned %i\n",
870 			__func__, rc);
871 }
872 
873 int xprt_rdma_init(void)
874 {
875 	int rc;
876 
877 	rc = rpcrdma_alloc_wq();
878 	if (rc)
879 		return rc;
880 
881 	rc = xprt_register_transport(&xprt_rdma);
882 	if (rc) {
883 		rpcrdma_destroy_wq();
884 		return rc;
885 	}
886 
887 	rc = xprt_register_transport(&xprt_rdma_bc);
888 	if (rc) {
889 		xprt_unregister_transport(&xprt_rdma);
890 		rpcrdma_destroy_wq();
891 		return rc;
892 	}
893 
894 	dprintk("RPCRDMA Module Init, register RPC RDMA transport\n");
895 
896 	dprintk("Defaults:\n");
897 	dprintk("\tSlots %d\n"
898 		"\tMaxInlineRead %d\n\tMaxInlineWrite %d\n",
899 		xprt_rdma_slot_table_entries,
900 		xprt_rdma_max_inline_read, xprt_rdma_max_inline_write);
901 	dprintk("\tPadding 0\n\tMemreg %d\n", xprt_rdma_memreg_strategy);
902 
903 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
904 	if (!sunrpc_table_header)
905 		sunrpc_table_header = register_sysctl_table(sunrpc_table);
906 #endif
907 	return 0;
908 }
909