xref: /openbmc/linux/net/sunrpc/xprtrdma/verbs.c (revision 4ed91d48259d9ddd378424d008f2e6559f7e78f8)
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  * verbs.c
42  *
43  * Encapsulates the major functions managing:
44  *  o adapters
45  *  o endpoints
46  *  o connections
47  *  o buffer memory
48  */
49 
50 #include <linux/interrupt.h>
51 #include <linux/slab.h>
52 #include <linux/prefetch.h>
53 #include <linux/sunrpc/addr.h>
54 #include <linux/sunrpc/svc_rdma.h>
55 #include <asm/bitops.h>
56 #include <linux/module.h> /* try_module_get()/module_put() */
57 #include <rdma/ib_cm.h>
58 
59 #include "xprt_rdma.h"
60 
61 /*
62  * Globals/Macros
63  */
64 
65 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
66 # define RPCDBG_FACILITY	RPCDBG_TRANS
67 #endif
68 
69 /*
70  * internal functions
71  */
72 
73 static struct workqueue_struct *rpcrdma_receive_wq;
74 
75 int
76 rpcrdma_alloc_wq(void)
77 {
78 	struct workqueue_struct *recv_wq;
79 
80 	recv_wq = alloc_workqueue("xprtrdma_receive",
81 				  WQ_MEM_RECLAIM | WQ_UNBOUND | WQ_HIGHPRI,
82 				  0);
83 	if (!recv_wq)
84 		return -ENOMEM;
85 
86 	rpcrdma_receive_wq = recv_wq;
87 	return 0;
88 }
89 
90 void
91 rpcrdma_destroy_wq(void)
92 {
93 	struct workqueue_struct *wq;
94 
95 	if (rpcrdma_receive_wq) {
96 		wq = rpcrdma_receive_wq;
97 		rpcrdma_receive_wq = NULL;
98 		destroy_workqueue(wq);
99 	}
100 }
101 
102 static void
103 rpcrdma_qp_async_error_upcall(struct ib_event *event, void *context)
104 {
105 	struct rpcrdma_ep *ep = context;
106 
107 	pr_err("rpcrdma: %s on device %s ep %p\n",
108 	       ib_event_msg(event->event), event->device->name, context);
109 
110 	if (ep->rep_connected == 1) {
111 		ep->rep_connected = -EIO;
112 		rpcrdma_conn_func(ep);
113 		wake_up_all(&ep->rep_connect_wait);
114 	}
115 }
116 
117 /**
118  * rpcrdma_wc_send - Invoked by RDMA provider for each polled Send WC
119  * @cq:	completion queue (ignored)
120  * @wc:	completed WR
121  *
122  */
123 static void
124 rpcrdma_wc_send(struct ib_cq *cq, struct ib_wc *wc)
125 {
126 	/* WARNING: Only wr_cqe and status are reliable at this point */
127 	if (wc->status != IB_WC_SUCCESS && wc->status != IB_WC_WR_FLUSH_ERR)
128 		pr_err("rpcrdma: Send: %s (%u/0x%x)\n",
129 		       ib_wc_status_msg(wc->status),
130 		       wc->status, wc->vendor_err);
131 }
132 
133 /* Perform basic sanity checking to avoid using garbage
134  * to update the credit grant value.
135  */
136 static void
137 rpcrdma_update_granted_credits(struct rpcrdma_rep *rep)
138 {
139 	struct rpcrdma_msg *rmsgp = rdmab_to_msg(rep->rr_rdmabuf);
140 	struct rpcrdma_buffer *buffer = &rep->rr_rxprt->rx_buf;
141 	u32 credits;
142 
143 	if (rep->rr_len < RPCRDMA_HDRLEN_ERR)
144 		return;
145 
146 	credits = be32_to_cpu(rmsgp->rm_credit);
147 	if (credits == 0)
148 		credits = 1;	/* don't deadlock */
149 	else if (credits > buffer->rb_max_requests)
150 		credits = buffer->rb_max_requests;
151 
152 	atomic_set(&buffer->rb_credits, credits);
153 }
154 
155 /**
156  * rpcrdma_wc_receive - Invoked by RDMA provider for each polled Receive WC
157  * @cq:	completion queue (ignored)
158  * @wc:	completed WR
159  *
160  */
161 static void
162 rpcrdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc)
163 {
164 	struct ib_cqe *cqe = wc->wr_cqe;
165 	struct rpcrdma_rep *rep = container_of(cqe, struct rpcrdma_rep,
166 					       rr_cqe);
167 
168 	/* WARNING: Only wr_id and status are reliable at this point */
169 	if (wc->status != IB_WC_SUCCESS)
170 		goto out_fail;
171 
172 	/* status == SUCCESS means all fields in wc are trustworthy */
173 	if (wc->opcode != IB_WC_RECV)
174 		return;
175 
176 	dprintk("RPC:       %s: rep %p opcode 'recv', length %u: success\n",
177 		__func__, rep, wc->byte_len);
178 
179 	rep->rr_len = wc->byte_len;
180 	rep->rr_wc_flags = wc->wc_flags;
181 	rep->rr_inv_rkey = wc->ex.invalidate_rkey;
182 
183 	ib_dma_sync_single_for_cpu(rep->rr_device,
184 				   rdmab_addr(rep->rr_rdmabuf),
185 				   rep->rr_len, DMA_FROM_DEVICE);
186 
187 	rpcrdma_update_granted_credits(rep);
188 
189 out_schedule:
190 	queue_work(rpcrdma_receive_wq, &rep->rr_work);
191 	return;
192 
193 out_fail:
194 	if (wc->status != IB_WC_WR_FLUSH_ERR)
195 		pr_err("rpcrdma: Recv: %s (%u/0x%x)\n",
196 		       ib_wc_status_msg(wc->status),
197 		       wc->status, wc->vendor_err);
198 	rep->rr_len = RPCRDMA_BAD_LEN;
199 	goto out_schedule;
200 }
201 
202 static void
203 rpcrdma_update_connect_private(struct rpcrdma_xprt *r_xprt,
204 			       struct rdma_conn_param *param)
205 {
206 	struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data;
207 	const struct rpcrdma_connect_private *pmsg = param->private_data;
208 	unsigned int rsize, wsize;
209 
210 	/* Default settings for RPC-over-RDMA Version One */
211 	r_xprt->rx_ia.ri_reminv_expected = false;
212 	r_xprt->rx_ia.ri_implicit_roundup = xprt_rdma_pad_optimize;
213 	rsize = RPCRDMA_V1_DEF_INLINE_SIZE;
214 	wsize = RPCRDMA_V1_DEF_INLINE_SIZE;
215 
216 	if (pmsg &&
217 	    pmsg->cp_magic == rpcrdma_cmp_magic &&
218 	    pmsg->cp_version == RPCRDMA_CMP_VERSION) {
219 		r_xprt->rx_ia.ri_reminv_expected = true;
220 		r_xprt->rx_ia.ri_implicit_roundup = true;
221 		rsize = rpcrdma_decode_buffer_size(pmsg->cp_send_size);
222 		wsize = rpcrdma_decode_buffer_size(pmsg->cp_recv_size);
223 	}
224 
225 	if (rsize < cdata->inline_rsize)
226 		cdata->inline_rsize = rsize;
227 	if (wsize < cdata->inline_wsize)
228 		cdata->inline_wsize = wsize;
229 	dprintk("RPC:       %s: max send %u, max recv %u\n",
230 		__func__, cdata->inline_wsize, cdata->inline_rsize);
231 	rpcrdma_set_max_header_sizes(r_xprt);
232 }
233 
234 static int
235 rpcrdma_conn_upcall(struct rdma_cm_id *id, struct rdma_cm_event *event)
236 {
237 	struct rpcrdma_xprt *xprt = id->context;
238 	struct rpcrdma_ia *ia = &xprt->rx_ia;
239 	struct rpcrdma_ep *ep = &xprt->rx_ep;
240 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
241 	struct sockaddr *sap = (struct sockaddr *)&ep->rep_remote_addr;
242 #endif
243 	struct ib_qp_attr *attr = &ia->ri_qp_attr;
244 	struct ib_qp_init_attr *iattr = &ia->ri_qp_init_attr;
245 	int connstate = 0;
246 
247 	switch (event->event) {
248 	case RDMA_CM_EVENT_ADDR_RESOLVED:
249 	case RDMA_CM_EVENT_ROUTE_RESOLVED:
250 		ia->ri_async_rc = 0;
251 		complete(&ia->ri_done);
252 		break;
253 	case RDMA_CM_EVENT_ADDR_ERROR:
254 		ia->ri_async_rc = -EHOSTUNREACH;
255 		dprintk("RPC:       %s: CM address resolution error, ep 0x%p\n",
256 			__func__, ep);
257 		complete(&ia->ri_done);
258 		break;
259 	case RDMA_CM_EVENT_ROUTE_ERROR:
260 		ia->ri_async_rc = -ENETUNREACH;
261 		dprintk("RPC:       %s: CM route resolution error, ep 0x%p\n",
262 			__func__, ep);
263 		complete(&ia->ri_done);
264 		break;
265 	case RDMA_CM_EVENT_ESTABLISHED:
266 		connstate = 1;
267 		ib_query_qp(ia->ri_id->qp, attr,
268 			    IB_QP_MAX_QP_RD_ATOMIC | IB_QP_MAX_DEST_RD_ATOMIC,
269 			    iattr);
270 		dprintk("RPC:       %s: %d responder resources"
271 			" (%d initiator)\n",
272 			__func__, attr->max_dest_rd_atomic,
273 			attr->max_rd_atomic);
274 		rpcrdma_update_connect_private(xprt, &event->param.conn);
275 		goto connected;
276 	case RDMA_CM_EVENT_CONNECT_ERROR:
277 		connstate = -ENOTCONN;
278 		goto connected;
279 	case RDMA_CM_EVENT_UNREACHABLE:
280 		connstate = -ENETDOWN;
281 		goto connected;
282 	case RDMA_CM_EVENT_REJECTED:
283 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
284 		pr_info("rpcrdma: connection to %pIS:%u on %s rejected: %s\n",
285 			sap, rpc_get_port(sap), ia->ri_device->name,
286 			rdma_reject_msg(id, event->status));
287 #endif
288 		connstate = -ECONNREFUSED;
289 		if (event->status == IB_CM_REJ_STALE_CONN)
290 			connstate = -EAGAIN;
291 		goto connected;
292 	case RDMA_CM_EVENT_DISCONNECTED:
293 		connstate = -ECONNABORTED;
294 		goto connected;
295 	case RDMA_CM_EVENT_DEVICE_REMOVAL:
296 		connstate = -ENODEV;
297 connected:
298 		dprintk("RPC:       %s: %sconnected\n",
299 					__func__, connstate > 0 ? "" : "dis");
300 		atomic_set(&xprt->rx_buf.rb_credits, 1);
301 		ep->rep_connected = connstate;
302 		rpcrdma_conn_func(ep);
303 		wake_up_all(&ep->rep_connect_wait);
304 		/*FALLTHROUGH*/
305 	default:
306 		dprintk("RPC:       %s: %pIS:%u (ep 0x%p): %s\n",
307 			__func__, sap, rpc_get_port(sap), ep,
308 			rdma_event_msg(event->event));
309 		break;
310 	}
311 
312 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
313 	if (connstate == 1) {
314 		int ird = attr->max_dest_rd_atomic;
315 		int tird = ep->rep_remote_cma.responder_resources;
316 
317 		pr_info("rpcrdma: connection to %pIS:%u on %s, memreg '%s', %d credits, %d responders%s\n",
318 			sap, rpc_get_port(sap),
319 			ia->ri_device->name,
320 			ia->ri_ops->ro_displayname,
321 			xprt->rx_buf.rb_max_requests,
322 			ird, ird < 4 && ird < tird / 2 ? " (low!)" : "");
323 	} else if (connstate < 0) {
324 		pr_info("rpcrdma: connection to %pIS:%u closed (%d)\n",
325 			sap, rpc_get_port(sap), connstate);
326 	}
327 #endif
328 
329 	return 0;
330 }
331 
332 static void rpcrdma_destroy_id(struct rdma_cm_id *id)
333 {
334 	if (id) {
335 		module_put(id->device->owner);
336 		rdma_destroy_id(id);
337 	}
338 }
339 
340 static struct rdma_cm_id *
341 rpcrdma_create_id(struct rpcrdma_xprt *xprt,
342 			struct rpcrdma_ia *ia, struct sockaddr *addr)
343 {
344 	unsigned long wtimeout = msecs_to_jiffies(RDMA_RESOLVE_TIMEOUT) + 1;
345 	struct rdma_cm_id *id;
346 	int rc;
347 
348 	init_completion(&ia->ri_done);
349 
350 	id = rdma_create_id(&init_net, rpcrdma_conn_upcall, xprt, RDMA_PS_TCP,
351 			    IB_QPT_RC);
352 	if (IS_ERR(id)) {
353 		rc = PTR_ERR(id);
354 		dprintk("RPC:       %s: rdma_create_id() failed %i\n",
355 			__func__, rc);
356 		return id;
357 	}
358 
359 	ia->ri_async_rc = -ETIMEDOUT;
360 	rc = rdma_resolve_addr(id, NULL, addr, RDMA_RESOLVE_TIMEOUT);
361 	if (rc) {
362 		dprintk("RPC:       %s: rdma_resolve_addr() failed %i\n",
363 			__func__, rc);
364 		goto out;
365 	}
366 	rc = wait_for_completion_interruptible_timeout(&ia->ri_done, wtimeout);
367 	if (rc < 0) {
368 		dprintk("RPC:       %s: wait() exited: %i\n",
369 			__func__, rc);
370 		goto out;
371 	}
372 
373 	/* FIXME:
374 	 * Until xprtrdma supports DEVICE_REMOVAL, the provider must
375 	 * be pinned while there are active NFS/RDMA mounts to prevent
376 	 * hangs and crashes at umount time.
377 	 */
378 	if (!ia->ri_async_rc && !try_module_get(id->device->owner)) {
379 		dprintk("RPC:       %s: Failed to get device module\n",
380 			__func__);
381 		ia->ri_async_rc = -ENODEV;
382 	}
383 	rc = ia->ri_async_rc;
384 	if (rc)
385 		goto out;
386 
387 	ia->ri_async_rc = -ETIMEDOUT;
388 	rc = rdma_resolve_route(id, RDMA_RESOLVE_TIMEOUT);
389 	if (rc) {
390 		dprintk("RPC:       %s: rdma_resolve_route() failed %i\n",
391 			__func__, rc);
392 		goto put;
393 	}
394 	rc = wait_for_completion_interruptible_timeout(&ia->ri_done, wtimeout);
395 	if (rc < 0) {
396 		dprintk("RPC:       %s: wait() exited: %i\n",
397 			__func__, rc);
398 		goto put;
399 	}
400 	rc = ia->ri_async_rc;
401 	if (rc)
402 		goto put;
403 
404 	return id;
405 put:
406 	module_put(id->device->owner);
407 out:
408 	rdma_destroy_id(id);
409 	return ERR_PTR(rc);
410 }
411 
412 /*
413  * Exported functions.
414  */
415 
416 /*
417  * Open and initialize an Interface Adapter.
418  *  o initializes fields of struct rpcrdma_ia, including
419  *    interface and provider attributes and protection zone.
420  */
421 int
422 rpcrdma_ia_open(struct rpcrdma_xprt *xprt, struct sockaddr *addr, int memreg)
423 {
424 	struct rpcrdma_ia *ia = &xprt->rx_ia;
425 	int rc;
426 
427 	ia->ri_id = rpcrdma_create_id(xprt, ia, addr);
428 	if (IS_ERR(ia->ri_id)) {
429 		rc = PTR_ERR(ia->ri_id);
430 		goto out1;
431 	}
432 	ia->ri_device = ia->ri_id->device;
433 
434 	ia->ri_pd = ib_alloc_pd(ia->ri_device, 0);
435 	if (IS_ERR(ia->ri_pd)) {
436 		rc = PTR_ERR(ia->ri_pd);
437 		pr_err("rpcrdma: ib_alloc_pd() returned %d\n", rc);
438 		goto out2;
439 	}
440 
441 	switch (memreg) {
442 	case RPCRDMA_FRMR:
443 		if (frwr_is_supported(ia)) {
444 			ia->ri_ops = &rpcrdma_frwr_memreg_ops;
445 			break;
446 		}
447 		/*FALLTHROUGH*/
448 	case RPCRDMA_MTHCAFMR:
449 		if (fmr_is_supported(ia)) {
450 			ia->ri_ops = &rpcrdma_fmr_memreg_ops;
451 			break;
452 		}
453 		/*FALLTHROUGH*/
454 	default:
455 		pr_err("rpcrdma: Unsupported memory registration mode: %d\n",
456 		       memreg);
457 		rc = -EINVAL;
458 		goto out3;
459 	}
460 
461 	return 0;
462 
463 out3:
464 	ib_dealloc_pd(ia->ri_pd);
465 	ia->ri_pd = NULL;
466 out2:
467 	rpcrdma_destroy_id(ia->ri_id);
468 	ia->ri_id = NULL;
469 out1:
470 	return rc;
471 }
472 
473 /*
474  * Clean up/close an IA.
475  *   o if event handles and PD have been initialized, free them.
476  *   o close the IA
477  */
478 void
479 rpcrdma_ia_close(struct rpcrdma_ia *ia)
480 {
481 	dprintk("RPC:       %s: entering\n", __func__);
482 	if (ia->ri_id != NULL && !IS_ERR(ia->ri_id)) {
483 		if (ia->ri_id->qp)
484 			rdma_destroy_qp(ia->ri_id);
485 		rpcrdma_destroy_id(ia->ri_id);
486 		ia->ri_id = NULL;
487 	}
488 
489 	/* If the pd is still busy, xprtrdma missed freeing a resource */
490 	if (ia->ri_pd && !IS_ERR(ia->ri_pd))
491 		ib_dealloc_pd(ia->ri_pd);
492 }
493 
494 /*
495  * Create unconnected endpoint.
496  */
497 int
498 rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
499 		  struct rpcrdma_create_data_internal *cdata)
500 {
501 	struct rpcrdma_connect_private *pmsg = &ep->rep_cm_private;
502 	unsigned int max_qp_wr, max_sge;
503 	struct ib_cq *sendcq, *recvcq;
504 	int rc;
505 
506 	max_sge = min(ia->ri_device->attrs.max_sge, RPCRDMA_MAX_SEND_SGES);
507 	if (max_sge < RPCRDMA_MIN_SEND_SGES) {
508 		pr_warn("rpcrdma: HCA provides only %d send SGEs\n", max_sge);
509 		return -ENOMEM;
510 	}
511 	ia->ri_max_send_sges = max_sge - RPCRDMA_MIN_SEND_SGES;
512 
513 	if (ia->ri_device->attrs.max_qp_wr <= RPCRDMA_BACKWARD_WRS) {
514 		dprintk("RPC:       %s: insufficient wqe's available\n",
515 			__func__);
516 		return -ENOMEM;
517 	}
518 	max_qp_wr = ia->ri_device->attrs.max_qp_wr - RPCRDMA_BACKWARD_WRS - 1;
519 
520 	/* check provider's send/recv wr limits */
521 	if (cdata->max_requests > max_qp_wr)
522 		cdata->max_requests = max_qp_wr;
523 
524 	ep->rep_attr.event_handler = rpcrdma_qp_async_error_upcall;
525 	ep->rep_attr.qp_context = ep;
526 	ep->rep_attr.srq = NULL;
527 	ep->rep_attr.cap.max_send_wr = cdata->max_requests;
528 	ep->rep_attr.cap.max_send_wr += RPCRDMA_BACKWARD_WRS;
529 	ep->rep_attr.cap.max_send_wr += 1;	/* drain cqe */
530 	rc = ia->ri_ops->ro_open(ia, ep, cdata);
531 	if (rc)
532 		return rc;
533 	ep->rep_attr.cap.max_recv_wr = cdata->max_requests;
534 	ep->rep_attr.cap.max_recv_wr += RPCRDMA_BACKWARD_WRS;
535 	ep->rep_attr.cap.max_recv_wr += 1;	/* drain cqe */
536 	ep->rep_attr.cap.max_send_sge = max_sge;
537 	ep->rep_attr.cap.max_recv_sge = 1;
538 	ep->rep_attr.cap.max_inline_data = 0;
539 	ep->rep_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
540 	ep->rep_attr.qp_type = IB_QPT_RC;
541 	ep->rep_attr.port_num = ~0;
542 
543 	dprintk("RPC:       %s: requested max: dtos: send %d recv %d; "
544 		"iovs: send %d recv %d\n",
545 		__func__,
546 		ep->rep_attr.cap.max_send_wr,
547 		ep->rep_attr.cap.max_recv_wr,
548 		ep->rep_attr.cap.max_send_sge,
549 		ep->rep_attr.cap.max_recv_sge);
550 
551 	/* set trigger for requesting send completion */
552 	ep->rep_cqinit = ep->rep_attr.cap.max_send_wr/2 - 1;
553 	if (ep->rep_cqinit <= 2)
554 		ep->rep_cqinit = 0;	/* always signal? */
555 	rpcrdma_init_cqcount(ep, 0);
556 	init_waitqueue_head(&ep->rep_connect_wait);
557 	INIT_DELAYED_WORK(&ep->rep_connect_worker, rpcrdma_connect_worker);
558 
559 	sendcq = ib_alloc_cq(ia->ri_device, NULL,
560 			     ep->rep_attr.cap.max_send_wr + 1,
561 			     0, IB_POLL_SOFTIRQ);
562 	if (IS_ERR(sendcq)) {
563 		rc = PTR_ERR(sendcq);
564 		dprintk("RPC:       %s: failed to create send CQ: %i\n",
565 			__func__, rc);
566 		goto out1;
567 	}
568 
569 	recvcq = ib_alloc_cq(ia->ri_device, NULL,
570 			     ep->rep_attr.cap.max_recv_wr + 1,
571 			     0, IB_POLL_SOFTIRQ);
572 	if (IS_ERR(recvcq)) {
573 		rc = PTR_ERR(recvcq);
574 		dprintk("RPC:       %s: failed to create recv CQ: %i\n",
575 			__func__, rc);
576 		goto out2;
577 	}
578 
579 	ep->rep_attr.send_cq = sendcq;
580 	ep->rep_attr.recv_cq = recvcq;
581 
582 	/* Initialize cma parameters */
583 	memset(&ep->rep_remote_cma, 0, sizeof(ep->rep_remote_cma));
584 
585 	/* Prepare RDMA-CM private message */
586 	pmsg->cp_magic = rpcrdma_cmp_magic;
587 	pmsg->cp_version = RPCRDMA_CMP_VERSION;
588 	pmsg->cp_flags |= ia->ri_ops->ro_send_w_inv_ok;
589 	pmsg->cp_send_size = rpcrdma_encode_buffer_size(cdata->inline_wsize);
590 	pmsg->cp_recv_size = rpcrdma_encode_buffer_size(cdata->inline_rsize);
591 	ep->rep_remote_cma.private_data = pmsg;
592 	ep->rep_remote_cma.private_data_len = sizeof(*pmsg);
593 
594 	/* Client offers RDMA Read but does not initiate */
595 	ep->rep_remote_cma.initiator_depth = 0;
596 	if (ia->ri_device->attrs.max_qp_rd_atom > 32)	/* arbitrary but <= 255 */
597 		ep->rep_remote_cma.responder_resources = 32;
598 	else
599 		ep->rep_remote_cma.responder_resources =
600 						ia->ri_device->attrs.max_qp_rd_atom;
601 
602 	/* Limit transport retries so client can detect server
603 	 * GID changes quickly. RPC layer handles re-establishing
604 	 * transport connection and retransmission.
605 	 */
606 	ep->rep_remote_cma.retry_count = 6;
607 
608 	/* RPC-over-RDMA handles its own flow control. In addition,
609 	 * make all RNR NAKs visible so we know that RPC-over-RDMA
610 	 * flow control is working correctly (no NAKs should be seen).
611 	 */
612 	ep->rep_remote_cma.flow_control = 0;
613 	ep->rep_remote_cma.rnr_retry_count = 0;
614 
615 	return 0;
616 
617 out2:
618 	ib_free_cq(sendcq);
619 out1:
620 	return rc;
621 }
622 
623 /*
624  * rpcrdma_ep_destroy
625  *
626  * Disconnect and destroy endpoint. After this, the only
627  * valid operations on the ep are to free it (if dynamically
628  * allocated) or re-create it.
629  */
630 void
631 rpcrdma_ep_destroy(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
632 {
633 	dprintk("RPC:       %s: entering, connected is %d\n",
634 		__func__, ep->rep_connected);
635 
636 	cancel_delayed_work_sync(&ep->rep_connect_worker);
637 
638 	if (ia->ri_id->qp) {
639 		rpcrdma_ep_disconnect(ep, ia);
640 		rdma_destroy_qp(ia->ri_id);
641 		ia->ri_id->qp = NULL;
642 	}
643 
644 	ib_free_cq(ep->rep_attr.recv_cq);
645 	ib_free_cq(ep->rep_attr.send_cq);
646 }
647 
648 /*
649  * Connect unconnected endpoint.
650  */
651 int
652 rpcrdma_ep_connect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
653 {
654 	struct rpcrdma_xprt *r_xprt = container_of(ia, struct rpcrdma_xprt,
655 						   rx_ia);
656 	struct rdma_cm_id *id, *old;
657 	struct sockaddr *sap;
658 	unsigned int extras;
659 	int rc = 0;
660 
661 	if (ep->rep_connected != 0) {
662 retry:
663 		dprintk("RPC:       %s: reconnecting...\n", __func__);
664 
665 		rpcrdma_ep_disconnect(ep, ia);
666 
667 		sap = (struct sockaddr *)&r_xprt->rx_data.addr;
668 		id = rpcrdma_create_id(r_xprt, ia, sap);
669 		if (IS_ERR(id)) {
670 			rc = -EHOSTUNREACH;
671 			goto out;
672 		}
673 		/* TEMP TEMP TEMP - fail if new device:
674 		 * Deregister/remarshal *all* requests!
675 		 * Close and recreate adapter, pd, etc!
676 		 * Re-determine all attributes still sane!
677 		 * More stuff I haven't thought of!
678 		 * Rrrgh!
679 		 */
680 		if (ia->ri_device != id->device) {
681 			printk("RPC:       %s: can't reconnect on "
682 				"different device!\n", __func__);
683 			rpcrdma_destroy_id(id);
684 			rc = -ENETUNREACH;
685 			goto out;
686 		}
687 		/* END TEMP */
688 		rc = rdma_create_qp(id, ia->ri_pd, &ep->rep_attr);
689 		if (rc) {
690 			dprintk("RPC:       %s: rdma_create_qp failed %i\n",
691 				__func__, rc);
692 			rpcrdma_destroy_id(id);
693 			rc = -ENETUNREACH;
694 			goto out;
695 		}
696 
697 		old = ia->ri_id;
698 		ia->ri_id = id;
699 
700 		rdma_destroy_qp(old);
701 		rpcrdma_destroy_id(old);
702 	} else {
703 		dprintk("RPC:       %s: connecting...\n", __func__);
704 		rc = rdma_create_qp(ia->ri_id, ia->ri_pd, &ep->rep_attr);
705 		if (rc) {
706 			dprintk("RPC:       %s: rdma_create_qp failed %i\n",
707 				__func__, rc);
708 			/* do not update ep->rep_connected */
709 			return -ENETUNREACH;
710 		}
711 	}
712 
713 	ep->rep_connected = 0;
714 
715 	rc = rdma_connect(ia->ri_id, &ep->rep_remote_cma);
716 	if (rc) {
717 		dprintk("RPC:       %s: rdma_connect() failed with %i\n",
718 				__func__, rc);
719 		goto out;
720 	}
721 
722 	wait_event_interruptible(ep->rep_connect_wait, ep->rep_connected != 0);
723 	if (ep->rep_connected <= 0) {
724 		if (ep->rep_connected == -EAGAIN)
725 			goto retry;
726 		rc = ep->rep_connected;
727 		goto out;
728 	}
729 
730 	dprintk("RPC:       %s: connected\n", __func__);
731 	extras = r_xprt->rx_buf.rb_bc_srv_max_requests;
732 	if (extras)
733 		rpcrdma_ep_post_extra_recv(r_xprt, extras);
734 
735 out:
736 	if (rc)
737 		ep->rep_connected = rc;
738 	return rc;
739 }
740 
741 /*
742  * rpcrdma_ep_disconnect
743  *
744  * This is separate from destroy to facilitate the ability
745  * to reconnect without recreating the endpoint.
746  *
747  * This call is not reentrant, and must not be made in parallel
748  * on the same endpoint.
749  */
750 void
751 rpcrdma_ep_disconnect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
752 {
753 	int rc;
754 
755 	rc = rdma_disconnect(ia->ri_id);
756 	if (!rc) {
757 		/* returns without wait if not connected */
758 		wait_event_interruptible(ep->rep_connect_wait,
759 							ep->rep_connected != 1);
760 		dprintk("RPC:       %s: after wait, %sconnected\n", __func__,
761 			(ep->rep_connected == 1) ? "still " : "dis");
762 	} else {
763 		dprintk("RPC:       %s: rdma_disconnect %i\n", __func__, rc);
764 		ep->rep_connected = rc;
765 	}
766 
767 	ib_drain_qp(ia->ri_id->qp);
768 }
769 
770 static void
771 rpcrdma_mr_recovery_worker(struct work_struct *work)
772 {
773 	struct rpcrdma_buffer *buf = container_of(work, struct rpcrdma_buffer,
774 						  rb_recovery_worker.work);
775 	struct rpcrdma_mw *mw;
776 
777 	spin_lock(&buf->rb_recovery_lock);
778 	while (!list_empty(&buf->rb_stale_mrs)) {
779 		mw = rpcrdma_pop_mw(&buf->rb_stale_mrs);
780 		spin_unlock(&buf->rb_recovery_lock);
781 
782 		dprintk("RPC:       %s: recovering MR %p\n", __func__, mw);
783 		mw->mw_xprt->rx_ia.ri_ops->ro_recover_mr(mw);
784 
785 		spin_lock(&buf->rb_recovery_lock);
786 	}
787 	spin_unlock(&buf->rb_recovery_lock);
788 }
789 
790 void
791 rpcrdma_defer_mr_recovery(struct rpcrdma_mw *mw)
792 {
793 	struct rpcrdma_xprt *r_xprt = mw->mw_xprt;
794 	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
795 
796 	spin_lock(&buf->rb_recovery_lock);
797 	rpcrdma_push_mw(mw, &buf->rb_stale_mrs);
798 	spin_unlock(&buf->rb_recovery_lock);
799 
800 	schedule_delayed_work(&buf->rb_recovery_worker, 0);
801 }
802 
803 static void
804 rpcrdma_create_mrs(struct rpcrdma_xprt *r_xprt)
805 {
806 	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
807 	struct rpcrdma_ia *ia = &r_xprt->rx_ia;
808 	unsigned int count;
809 	LIST_HEAD(free);
810 	LIST_HEAD(all);
811 
812 	for (count = 0; count < 32; count++) {
813 		struct rpcrdma_mw *mw;
814 		int rc;
815 
816 		mw = kzalloc(sizeof(*mw), GFP_KERNEL);
817 		if (!mw)
818 			break;
819 
820 		rc = ia->ri_ops->ro_init_mr(ia, mw);
821 		if (rc) {
822 			kfree(mw);
823 			break;
824 		}
825 
826 		mw->mw_xprt = r_xprt;
827 
828 		list_add(&mw->mw_list, &free);
829 		list_add(&mw->mw_all, &all);
830 	}
831 
832 	spin_lock(&buf->rb_mwlock);
833 	list_splice(&free, &buf->rb_mws);
834 	list_splice(&all, &buf->rb_all);
835 	r_xprt->rx_stats.mrs_allocated += count;
836 	spin_unlock(&buf->rb_mwlock);
837 
838 	dprintk("RPC:       %s: created %u MRs\n", __func__, count);
839 }
840 
841 static void
842 rpcrdma_mr_refresh_worker(struct work_struct *work)
843 {
844 	struct rpcrdma_buffer *buf = container_of(work, struct rpcrdma_buffer,
845 						  rb_refresh_worker.work);
846 	struct rpcrdma_xprt *r_xprt = container_of(buf, struct rpcrdma_xprt,
847 						   rx_buf);
848 
849 	rpcrdma_create_mrs(r_xprt);
850 }
851 
852 struct rpcrdma_req *
853 rpcrdma_create_req(struct rpcrdma_xprt *r_xprt)
854 {
855 	struct rpcrdma_buffer *buffer = &r_xprt->rx_buf;
856 	struct rpcrdma_req *req;
857 
858 	req = kzalloc(sizeof(*req), GFP_KERNEL);
859 	if (req == NULL)
860 		return ERR_PTR(-ENOMEM);
861 
862 	INIT_LIST_HEAD(&req->rl_free);
863 	spin_lock(&buffer->rb_reqslock);
864 	list_add(&req->rl_all, &buffer->rb_allreqs);
865 	spin_unlock(&buffer->rb_reqslock);
866 	req->rl_cqe.done = rpcrdma_wc_send;
867 	req->rl_buffer = &r_xprt->rx_buf;
868 	INIT_LIST_HEAD(&req->rl_registered);
869 	req->rl_send_wr.next = NULL;
870 	req->rl_send_wr.wr_cqe = &req->rl_cqe;
871 	req->rl_send_wr.sg_list = req->rl_send_sge;
872 	req->rl_send_wr.opcode = IB_WR_SEND;
873 	return req;
874 }
875 
876 struct rpcrdma_rep *
877 rpcrdma_create_rep(struct rpcrdma_xprt *r_xprt)
878 {
879 	struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data;
880 	struct rpcrdma_ia *ia = &r_xprt->rx_ia;
881 	struct rpcrdma_rep *rep;
882 	int rc;
883 
884 	rc = -ENOMEM;
885 	rep = kzalloc(sizeof(*rep), GFP_KERNEL);
886 	if (rep == NULL)
887 		goto out;
888 
889 	rep->rr_rdmabuf = rpcrdma_alloc_regbuf(cdata->inline_rsize,
890 					       DMA_FROM_DEVICE, GFP_KERNEL);
891 	if (IS_ERR(rep->rr_rdmabuf)) {
892 		rc = PTR_ERR(rep->rr_rdmabuf);
893 		goto out_free;
894 	}
895 
896 	rep->rr_device = ia->ri_device;
897 	rep->rr_cqe.done = rpcrdma_wc_receive;
898 	rep->rr_rxprt = r_xprt;
899 	INIT_WORK(&rep->rr_work, rpcrdma_reply_handler);
900 	rep->rr_recv_wr.next = NULL;
901 	rep->rr_recv_wr.wr_cqe = &rep->rr_cqe;
902 	rep->rr_recv_wr.sg_list = &rep->rr_rdmabuf->rg_iov;
903 	rep->rr_recv_wr.num_sge = 1;
904 	return rep;
905 
906 out_free:
907 	kfree(rep);
908 out:
909 	return ERR_PTR(rc);
910 }
911 
912 int
913 rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt)
914 {
915 	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
916 	int i, rc;
917 
918 	buf->rb_max_requests = r_xprt->rx_data.max_requests;
919 	buf->rb_bc_srv_max_requests = 0;
920 	atomic_set(&buf->rb_credits, 1);
921 	spin_lock_init(&buf->rb_mwlock);
922 	spin_lock_init(&buf->rb_lock);
923 	spin_lock_init(&buf->rb_recovery_lock);
924 	INIT_LIST_HEAD(&buf->rb_mws);
925 	INIT_LIST_HEAD(&buf->rb_all);
926 	INIT_LIST_HEAD(&buf->rb_stale_mrs);
927 	INIT_DELAYED_WORK(&buf->rb_refresh_worker,
928 			  rpcrdma_mr_refresh_worker);
929 	INIT_DELAYED_WORK(&buf->rb_recovery_worker,
930 			  rpcrdma_mr_recovery_worker);
931 
932 	rpcrdma_create_mrs(r_xprt);
933 
934 	INIT_LIST_HEAD(&buf->rb_send_bufs);
935 	INIT_LIST_HEAD(&buf->rb_allreqs);
936 	spin_lock_init(&buf->rb_reqslock);
937 	for (i = 0; i < buf->rb_max_requests; i++) {
938 		struct rpcrdma_req *req;
939 
940 		req = rpcrdma_create_req(r_xprt);
941 		if (IS_ERR(req)) {
942 			dprintk("RPC:       %s: request buffer %d alloc"
943 				" failed\n", __func__, i);
944 			rc = PTR_ERR(req);
945 			goto out;
946 		}
947 		req->rl_backchannel = false;
948 		list_add(&req->rl_free, &buf->rb_send_bufs);
949 	}
950 
951 	INIT_LIST_HEAD(&buf->rb_recv_bufs);
952 	for (i = 0; i < buf->rb_max_requests + RPCRDMA_MAX_BC_REQUESTS; i++) {
953 		struct rpcrdma_rep *rep;
954 
955 		rep = rpcrdma_create_rep(r_xprt);
956 		if (IS_ERR(rep)) {
957 			dprintk("RPC:       %s: reply buffer %d alloc failed\n",
958 				__func__, i);
959 			rc = PTR_ERR(rep);
960 			goto out;
961 		}
962 		list_add(&rep->rr_list, &buf->rb_recv_bufs);
963 	}
964 
965 	return 0;
966 out:
967 	rpcrdma_buffer_destroy(buf);
968 	return rc;
969 }
970 
971 static struct rpcrdma_req *
972 rpcrdma_buffer_get_req_locked(struct rpcrdma_buffer *buf)
973 {
974 	struct rpcrdma_req *req;
975 
976 	req = list_first_entry(&buf->rb_send_bufs,
977 			       struct rpcrdma_req, rl_free);
978 	list_del(&req->rl_free);
979 	return req;
980 }
981 
982 static struct rpcrdma_rep *
983 rpcrdma_buffer_get_rep_locked(struct rpcrdma_buffer *buf)
984 {
985 	struct rpcrdma_rep *rep;
986 
987 	rep = list_first_entry(&buf->rb_recv_bufs,
988 			       struct rpcrdma_rep, rr_list);
989 	list_del(&rep->rr_list);
990 	return rep;
991 }
992 
993 static void
994 rpcrdma_destroy_rep(struct rpcrdma_rep *rep)
995 {
996 	rpcrdma_free_regbuf(rep->rr_rdmabuf);
997 	kfree(rep);
998 }
999 
1000 void
1001 rpcrdma_destroy_req(struct rpcrdma_req *req)
1002 {
1003 	rpcrdma_free_regbuf(req->rl_recvbuf);
1004 	rpcrdma_free_regbuf(req->rl_sendbuf);
1005 	rpcrdma_free_regbuf(req->rl_rdmabuf);
1006 	kfree(req);
1007 }
1008 
1009 static void
1010 rpcrdma_destroy_mrs(struct rpcrdma_buffer *buf)
1011 {
1012 	struct rpcrdma_xprt *r_xprt = container_of(buf, struct rpcrdma_xprt,
1013 						   rx_buf);
1014 	struct rpcrdma_ia *ia = rdmab_to_ia(buf);
1015 	struct rpcrdma_mw *mw;
1016 	unsigned int count;
1017 
1018 	count = 0;
1019 	spin_lock(&buf->rb_mwlock);
1020 	while (!list_empty(&buf->rb_all)) {
1021 		mw = list_entry(buf->rb_all.next, struct rpcrdma_mw, mw_all);
1022 		list_del(&mw->mw_all);
1023 
1024 		spin_unlock(&buf->rb_mwlock);
1025 		ia->ri_ops->ro_release_mr(mw);
1026 		count++;
1027 		spin_lock(&buf->rb_mwlock);
1028 	}
1029 	spin_unlock(&buf->rb_mwlock);
1030 	r_xprt->rx_stats.mrs_allocated = 0;
1031 
1032 	dprintk("RPC:       %s: released %u MRs\n", __func__, count);
1033 }
1034 
1035 void
1036 rpcrdma_buffer_destroy(struct rpcrdma_buffer *buf)
1037 {
1038 	cancel_delayed_work_sync(&buf->rb_recovery_worker);
1039 
1040 	while (!list_empty(&buf->rb_recv_bufs)) {
1041 		struct rpcrdma_rep *rep;
1042 
1043 		rep = rpcrdma_buffer_get_rep_locked(buf);
1044 		rpcrdma_destroy_rep(rep);
1045 	}
1046 	buf->rb_send_count = 0;
1047 
1048 	spin_lock(&buf->rb_reqslock);
1049 	while (!list_empty(&buf->rb_allreqs)) {
1050 		struct rpcrdma_req *req;
1051 
1052 		req = list_first_entry(&buf->rb_allreqs,
1053 				       struct rpcrdma_req, rl_all);
1054 		list_del(&req->rl_all);
1055 
1056 		spin_unlock(&buf->rb_reqslock);
1057 		rpcrdma_destroy_req(req);
1058 		spin_lock(&buf->rb_reqslock);
1059 	}
1060 	spin_unlock(&buf->rb_reqslock);
1061 	buf->rb_recv_count = 0;
1062 
1063 	rpcrdma_destroy_mrs(buf);
1064 }
1065 
1066 struct rpcrdma_mw *
1067 rpcrdma_get_mw(struct rpcrdma_xprt *r_xprt)
1068 {
1069 	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
1070 	struct rpcrdma_mw *mw = NULL;
1071 
1072 	spin_lock(&buf->rb_mwlock);
1073 	if (!list_empty(&buf->rb_mws))
1074 		mw = rpcrdma_pop_mw(&buf->rb_mws);
1075 	spin_unlock(&buf->rb_mwlock);
1076 
1077 	if (!mw)
1078 		goto out_nomws;
1079 	return mw;
1080 
1081 out_nomws:
1082 	dprintk("RPC:       %s: no MWs available\n", __func__);
1083 	schedule_delayed_work(&buf->rb_refresh_worker, 0);
1084 
1085 	/* Allow the reply handler and refresh worker to run */
1086 	cond_resched();
1087 
1088 	return NULL;
1089 }
1090 
1091 void
1092 rpcrdma_put_mw(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mw *mw)
1093 {
1094 	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
1095 
1096 	spin_lock(&buf->rb_mwlock);
1097 	rpcrdma_push_mw(mw, &buf->rb_mws);
1098 	spin_unlock(&buf->rb_mwlock);
1099 }
1100 
1101 static struct rpcrdma_rep *
1102 rpcrdma_buffer_get_rep(struct rpcrdma_buffer *buffers)
1103 {
1104 	/* If an RPC previously completed without a reply (say, a
1105 	 * credential problem or a soft timeout occurs) then hold off
1106 	 * on supplying more Receive buffers until the number of new
1107 	 * pending RPCs catches up to the number of posted Receives.
1108 	 */
1109 	if (unlikely(buffers->rb_send_count < buffers->rb_recv_count))
1110 		return NULL;
1111 
1112 	if (unlikely(list_empty(&buffers->rb_recv_bufs)))
1113 		return NULL;
1114 	buffers->rb_recv_count++;
1115 	return rpcrdma_buffer_get_rep_locked(buffers);
1116 }
1117 
1118 /*
1119  * Get a set of request/reply buffers.
1120  *
1121  * Reply buffer (if available) is attached to send buffer upon return.
1122  */
1123 struct rpcrdma_req *
1124 rpcrdma_buffer_get(struct rpcrdma_buffer *buffers)
1125 {
1126 	struct rpcrdma_req *req;
1127 
1128 	spin_lock(&buffers->rb_lock);
1129 	if (list_empty(&buffers->rb_send_bufs))
1130 		goto out_reqbuf;
1131 	buffers->rb_send_count++;
1132 	req = rpcrdma_buffer_get_req_locked(buffers);
1133 	req->rl_reply = rpcrdma_buffer_get_rep(buffers);
1134 	spin_unlock(&buffers->rb_lock);
1135 	return req;
1136 
1137 out_reqbuf:
1138 	spin_unlock(&buffers->rb_lock);
1139 	pr_warn("RPC:       %s: out of request buffers\n", __func__);
1140 	return NULL;
1141 }
1142 
1143 /*
1144  * Put request/reply buffers back into pool.
1145  * Pre-decrement counter/array index.
1146  */
1147 void
1148 rpcrdma_buffer_put(struct rpcrdma_req *req)
1149 {
1150 	struct rpcrdma_buffer *buffers = req->rl_buffer;
1151 	struct rpcrdma_rep *rep = req->rl_reply;
1152 
1153 	req->rl_send_wr.num_sge = 0;
1154 	req->rl_reply = NULL;
1155 
1156 	spin_lock(&buffers->rb_lock);
1157 	buffers->rb_send_count--;
1158 	list_add_tail(&req->rl_free, &buffers->rb_send_bufs);
1159 	if (rep) {
1160 		buffers->rb_recv_count--;
1161 		list_add_tail(&rep->rr_list, &buffers->rb_recv_bufs);
1162 	}
1163 	spin_unlock(&buffers->rb_lock);
1164 }
1165 
1166 /*
1167  * Recover reply buffers from pool.
1168  * This happens when recovering from disconnect.
1169  */
1170 void
1171 rpcrdma_recv_buffer_get(struct rpcrdma_req *req)
1172 {
1173 	struct rpcrdma_buffer *buffers = req->rl_buffer;
1174 
1175 	spin_lock(&buffers->rb_lock);
1176 	req->rl_reply = rpcrdma_buffer_get_rep(buffers);
1177 	spin_unlock(&buffers->rb_lock);
1178 }
1179 
1180 /*
1181  * Put reply buffers back into pool when not attached to
1182  * request. This happens in error conditions.
1183  */
1184 void
1185 rpcrdma_recv_buffer_put(struct rpcrdma_rep *rep)
1186 {
1187 	struct rpcrdma_buffer *buffers = &rep->rr_rxprt->rx_buf;
1188 
1189 	spin_lock(&buffers->rb_lock);
1190 	buffers->rb_recv_count--;
1191 	list_add_tail(&rep->rr_list, &buffers->rb_recv_bufs);
1192 	spin_unlock(&buffers->rb_lock);
1193 }
1194 
1195 /**
1196  * rpcrdma_alloc_regbuf - allocate and DMA-map memory for SEND/RECV buffers
1197  * @size: size of buffer to be allocated, in bytes
1198  * @direction: direction of data movement
1199  * @flags: GFP flags
1200  *
1201  * Returns an ERR_PTR, or a pointer to a regbuf, a buffer that
1202  * can be persistently DMA-mapped for I/O.
1203  *
1204  * xprtrdma uses a regbuf for posting an outgoing RDMA SEND, or for
1205  * receiving the payload of RDMA RECV operations. During Long Calls
1206  * or Replies they may be registered externally via ro_map.
1207  */
1208 struct rpcrdma_regbuf *
1209 rpcrdma_alloc_regbuf(size_t size, enum dma_data_direction direction,
1210 		     gfp_t flags)
1211 {
1212 	struct rpcrdma_regbuf *rb;
1213 
1214 	rb = kmalloc(sizeof(*rb) + size, flags);
1215 	if (rb == NULL)
1216 		return ERR_PTR(-ENOMEM);
1217 
1218 	rb->rg_device = NULL;
1219 	rb->rg_direction = direction;
1220 	rb->rg_iov.length = size;
1221 
1222 	return rb;
1223 }
1224 
1225 /**
1226  * __rpcrdma_map_regbuf - DMA-map a regbuf
1227  * @ia: controlling rpcrdma_ia
1228  * @rb: regbuf to be mapped
1229  */
1230 bool
1231 __rpcrdma_dma_map_regbuf(struct rpcrdma_ia *ia, struct rpcrdma_regbuf *rb)
1232 {
1233 	if (rb->rg_direction == DMA_NONE)
1234 		return false;
1235 
1236 	rb->rg_iov.addr = ib_dma_map_single(ia->ri_device,
1237 					    (void *)rb->rg_base,
1238 					    rdmab_length(rb),
1239 					    rb->rg_direction);
1240 	if (ib_dma_mapping_error(ia->ri_device, rdmab_addr(rb)))
1241 		return false;
1242 
1243 	rb->rg_device = ia->ri_device;
1244 	rb->rg_iov.lkey = ia->ri_pd->local_dma_lkey;
1245 	return true;
1246 }
1247 
1248 static void
1249 rpcrdma_dma_unmap_regbuf(struct rpcrdma_regbuf *rb)
1250 {
1251 	if (!rpcrdma_regbuf_is_mapped(rb))
1252 		return;
1253 
1254 	ib_dma_unmap_single(rb->rg_device, rdmab_addr(rb),
1255 			    rdmab_length(rb), rb->rg_direction);
1256 	rb->rg_device = NULL;
1257 }
1258 
1259 /**
1260  * rpcrdma_free_regbuf - deregister and free registered buffer
1261  * @rb: regbuf to be deregistered and freed
1262  */
1263 void
1264 rpcrdma_free_regbuf(struct rpcrdma_regbuf *rb)
1265 {
1266 	if (!rb)
1267 		return;
1268 
1269 	rpcrdma_dma_unmap_regbuf(rb);
1270 	kfree(rb);
1271 }
1272 
1273 /*
1274  * Prepost any receive buffer, then post send.
1275  *
1276  * Receive buffer is donated to hardware, reclaimed upon recv completion.
1277  */
1278 int
1279 rpcrdma_ep_post(struct rpcrdma_ia *ia,
1280 		struct rpcrdma_ep *ep,
1281 		struct rpcrdma_req *req)
1282 {
1283 	struct ib_send_wr *send_wr = &req->rl_send_wr;
1284 	struct ib_send_wr *send_wr_fail;
1285 	int rc;
1286 
1287 	if (req->rl_reply) {
1288 		rc = rpcrdma_ep_post_recv(ia, req->rl_reply);
1289 		if (rc)
1290 			return rc;
1291 		req->rl_reply = NULL;
1292 	}
1293 
1294 	dprintk("RPC:       %s: posting %d s/g entries\n",
1295 		__func__, send_wr->num_sge);
1296 
1297 	rpcrdma_set_signaled(ep, send_wr);
1298 	rc = ib_post_send(ia->ri_id->qp, send_wr, &send_wr_fail);
1299 	if (rc)
1300 		goto out_postsend_err;
1301 	return 0;
1302 
1303 out_postsend_err:
1304 	pr_err("rpcrdma: RDMA Send ib_post_send returned %i\n", rc);
1305 	return -ENOTCONN;
1306 }
1307 
1308 int
1309 rpcrdma_ep_post_recv(struct rpcrdma_ia *ia,
1310 		     struct rpcrdma_rep *rep)
1311 {
1312 	struct ib_recv_wr *recv_wr_fail;
1313 	int rc;
1314 
1315 	if (!rpcrdma_dma_map_regbuf(ia, rep->rr_rdmabuf))
1316 		goto out_map;
1317 	rc = ib_post_recv(ia->ri_id->qp, &rep->rr_recv_wr, &recv_wr_fail);
1318 	if (rc)
1319 		goto out_postrecv;
1320 	return 0;
1321 
1322 out_map:
1323 	pr_err("rpcrdma: failed to DMA map the Receive buffer\n");
1324 	return -EIO;
1325 
1326 out_postrecv:
1327 	pr_err("rpcrdma: ib_post_recv returned %i\n", rc);
1328 	return -ENOTCONN;
1329 }
1330 
1331 /**
1332  * rpcrdma_ep_post_extra_recv - Post buffers for incoming backchannel requests
1333  * @r_xprt: transport associated with these backchannel resources
1334  * @min_reqs: minimum number of incoming requests expected
1335  *
1336  * Returns zero if all requested buffers were posted, or a negative errno.
1337  */
1338 int
1339 rpcrdma_ep_post_extra_recv(struct rpcrdma_xprt *r_xprt, unsigned int count)
1340 {
1341 	struct rpcrdma_buffer *buffers = &r_xprt->rx_buf;
1342 	struct rpcrdma_ia *ia = &r_xprt->rx_ia;
1343 	struct rpcrdma_rep *rep;
1344 	int rc;
1345 
1346 	while (count--) {
1347 		spin_lock(&buffers->rb_lock);
1348 		if (list_empty(&buffers->rb_recv_bufs))
1349 			goto out_reqbuf;
1350 		rep = rpcrdma_buffer_get_rep_locked(buffers);
1351 		spin_unlock(&buffers->rb_lock);
1352 
1353 		rc = rpcrdma_ep_post_recv(ia, rep);
1354 		if (rc)
1355 			goto out_rc;
1356 	}
1357 
1358 	return 0;
1359 
1360 out_reqbuf:
1361 	spin_unlock(&buffers->rb_lock);
1362 	pr_warn("%s: no extra receive buffers\n", __func__);
1363 	return -ENOMEM;
1364 
1365 out_rc:
1366 	rpcrdma_recv_buffer_put(rep);
1367 	return rc;
1368 }
1369