1 /*
2  * Copyright (c) 2014 Open Grid Computing, Inc. All rights reserved.
3  * Copyright (c) 2005-2007 Network Appliance, Inc. All rights reserved.
4  *
5  * This software is available to you under a choice of one of two
6  * licenses.  You may choose to be licensed under the terms of the GNU
7  * General Public License (GPL) Version 2, available from the file
8  * COPYING in the main directory of this source tree, or the BSD-type
9  * license below:
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  *
15  *      Redistributions of source code must retain the above copyright
16  *      notice, this list of conditions and the following disclaimer.
17  *
18  *      Redistributions in binary form must reproduce the above
19  *      copyright notice, this list of conditions and the following
20  *      disclaimer in the documentation and/or other materials provided
21  *      with the distribution.
22  *
23  *      Neither the name of the Network Appliance, Inc. nor the names of
24  *      its contributors may be used to endorse or promote products
25  *      derived from this software without specific prior written
26  *      permission.
27  *
28  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
31  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
32  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
33  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
34  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
38  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39  *
40  * Author: Tom Tucker <tom@opengridcomputing.com>
41  */
42 
43 #include <linux/sunrpc/svc_xprt.h>
44 #include <linux/sunrpc/addr.h>
45 #include <linux/sunrpc/debug.h>
46 #include <linux/sunrpc/rpc_rdma.h>
47 #include <linux/interrupt.h>
48 #include <linux/sched.h>
49 #include <linux/slab.h>
50 #include <linux/spinlock.h>
51 #include <linux/workqueue.h>
52 #include <rdma/ib_verbs.h>
53 #include <rdma/rdma_cm.h>
54 #include <linux/sunrpc/svc_rdma.h>
55 #include <linux/export.h>
56 #include "xprt_rdma.h"
57 
58 #define RPCDBG_FACILITY	RPCDBG_SVCXPRT
59 
60 static struct svcxprt_rdma *rdma_create_xprt(struct svc_serv *, int);
61 static struct svc_xprt *svc_rdma_create(struct svc_serv *serv,
62 					struct net *net,
63 					struct sockaddr *sa, int salen,
64 					int flags);
65 static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt);
66 static void svc_rdma_release_rqst(struct svc_rqst *);
67 static void svc_rdma_detach(struct svc_xprt *xprt);
68 static void svc_rdma_free(struct svc_xprt *xprt);
69 static int svc_rdma_has_wspace(struct svc_xprt *xprt);
70 static int svc_rdma_secure_port(struct svc_rqst *);
71 static void svc_rdma_kill_temp_xprt(struct svc_xprt *);
72 
73 static struct svc_xprt_ops svc_rdma_ops = {
74 	.xpo_create = svc_rdma_create,
75 	.xpo_recvfrom = svc_rdma_recvfrom,
76 	.xpo_sendto = svc_rdma_sendto,
77 	.xpo_release_rqst = svc_rdma_release_rqst,
78 	.xpo_detach = svc_rdma_detach,
79 	.xpo_free = svc_rdma_free,
80 	.xpo_prep_reply_hdr = svc_rdma_prep_reply_hdr,
81 	.xpo_has_wspace = svc_rdma_has_wspace,
82 	.xpo_accept = svc_rdma_accept,
83 	.xpo_secure_port = svc_rdma_secure_port,
84 	.xpo_kill_temp_xprt = svc_rdma_kill_temp_xprt,
85 };
86 
87 struct svc_xprt_class svc_rdma_class = {
88 	.xcl_name = "rdma",
89 	.xcl_owner = THIS_MODULE,
90 	.xcl_ops = &svc_rdma_ops,
91 	.xcl_max_payload = RPCSVC_MAXPAYLOAD_RDMA,
92 	.xcl_ident = XPRT_TRANSPORT_RDMA,
93 };
94 
95 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
96 static struct svc_xprt *svc_rdma_bc_create(struct svc_serv *, struct net *,
97 					   struct sockaddr *, int, int);
98 static void svc_rdma_bc_detach(struct svc_xprt *);
99 static void svc_rdma_bc_free(struct svc_xprt *);
100 
101 static struct svc_xprt_ops svc_rdma_bc_ops = {
102 	.xpo_create = svc_rdma_bc_create,
103 	.xpo_detach = svc_rdma_bc_detach,
104 	.xpo_free = svc_rdma_bc_free,
105 	.xpo_prep_reply_hdr = svc_rdma_prep_reply_hdr,
106 	.xpo_secure_port = svc_rdma_secure_port,
107 };
108 
109 struct svc_xprt_class svc_rdma_bc_class = {
110 	.xcl_name = "rdma-bc",
111 	.xcl_owner = THIS_MODULE,
112 	.xcl_ops = &svc_rdma_bc_ops,
113 	.xcl_max_payload = (1024 - RPCRDMA_HDRLEN_MIN)
114 };
115 
116 static struct svc_xprt *svc_rdma_bc_create(struct svc_serv *serv,
117 					   struct net *net,
118 					   struct sockaddr *sa, int salen,
119 					   int flags)
120 {
121 	struct svcxprt_rdma *cma_xprt;
122 	struct svc_xprt *xprt;
123 
124 	cma_xprt = rdma_create_xprt(serv, 0);
125 	if (!cma_xprt)
126 		return ERR_PTR(-ENOMEM);
127 	xprt = &cma_xprt->sc_xprt;
128 
129 	svc_xprt_init(net, &svc_rdma_bc_class, xprt, serv);
130 	serv->sv_bc_xprt = xprt;
131 
132 	dprintk("svcrdma: %s(%p)\n", __func__, xprt);
133 	return xprt;
134 }
135 
136 static void svc_rdma_bc_detach(struct svc_xprt *xprt)
137 {
138 	dprintk("svcrdma: %s(%p)\n", __func__, xprt);
139 }
140 
141 static void svc_rdma_bc_free(struct svc_xprt *xprt)
142 {
143 	struct svcxprt_rdma *rdma =
144 		container_of(xprt, struct svcxprt_rdma, sc_xprt);
145 
146 	dprintk("svcrdma: %s(%p)\n", __func__, xprt);
147 	if (xprt)
148 		kfree(rdma);
149 }
150 #endif	/* CONFIG_SUNRPC_BACKCHANNEL */
151 
152 static struct svc_rdma_op_ctxt *alloc_ctxt(struct svcxprt_rdma *xprt,
153 					   gfp_t flags)
154 {
155 	struct svc_rdma_op_ctxt *ctxt;
156 
157 	ctxt = kmalloc(sizeof(*ctxt), flags);
158 	if (ctxt) {
159 		ctxt->xprt = xprt;
160 		INIT_LIST_HEAD(&ctxt->free);
161 		INIT_LIST_HEAD(&ctxt->dto_q);
162 	}
163 	return ctxt;
164 }
165 
166 static bool svc_rdma_prealloc_ctxts(struct svcxprt_rdma *xprt)
167 {
168 	unsigned int i;
169 
170 	/* Each RPC/RDMA credit can consume a number of send
171 	 * and receive WQEs. One ctxt is allocated for each.
172 	 */
173 	i = xprt->sc_sq_depth + xprt->sc_rq_depth;
174 
175 	while (i--) {
176 		struct svc_rdma_op_ctxt *ctxt;
177 
178 		ctxt = alloc_ctxt(xprt, GFP_KERNEL);
179 		if (!ctxt) {
180 			dprintk("svcrdma: No memory for RDMA ctxt\n");
181 			return false;
182 		}
183 		list_add(&ctxt->free, &xprt->sc_ctxts);
184 	}
185 	return true;
186 }
187 
188 struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *xprt)
189 {
190 	struct svc_rdma_op_ctxt *ctxt = NULL;
191 
192 	spin_lock_bh(&xprt->sc_ctxt_lock);
193 	xprt->sc_ctxt_used++;
194 	if (list_empty(&xprt->sc_ctxts))
195 		goto out_empty;
196 
197 	ctxt = list_first_entry(&xprt->sc_ctxts,
198 				struct svc_rdma_op_ctxt, free);
199 	list_del_init(&ctxt->free);
200 	spin_unlock_bh(&xprt->sc_ctxt_lock);
201 
202 out:
203 	ctxt->count = 0;
204 	ctxt->mapped_sges = 0;
205 	ctxt->frmr = NULL;
206 	return ctxt;
207 
208 out_empty:
209 	/* Either pre-allocation missed the mark, or send
210 	 * queue accounting is broken.
211 	 */
212 	spin_unlock_bh(&xprt->sc_ctxt_lock);
213 
214 	ctxt = alloc_ctxt(xprt, GFP_NOIO);
215 	if (ctxt)
216 		goto out;
217 
218 	spin_lock_bh(&xprt->sc_ctxt_lock);
219 	xprt->sc_ctxt_used--;
220 	spin_unlock_bh(&xprt->sc_ctxt_lock);
221 	WARN_ONCE(1, "svcrdma: empty RDMA ctxt list?\n");
222 	return NULL;
223 }
224 
225 void svc_rdma_unmap_dma(struct svc_rdma_op_ctxt *ctxt)
226 {
227 	struct svcxprt_rdma *xprt = ctxt->xprt;
228 	struct ib_device *device = xprt->sc_cm_id->device;
229 	u32 lkey = xprt->sc_pd->local_dma_lkey;
230 	unsigned int i;
231 
232 	for (i = 0; i < ctxt->mapped_sges; i++) {
233 		/*
234 		 * Unmap the DMA addr in the SGE if the lkey matches
235 		 * the local_dma_lkey, otherwise, ignore it since it is
236 		 * an FRMR lkey and will be unmapped later when the
237 		 * last WR that uses it completes.
238 		 */
239 		if (ctxt->sge[i].lkey == lkey)
240 			ib_dma_unmap_page(device,
241 					    ctxt->sge[i].addr,
242 					    ctxt->sge[i].length,
243 					    ctxt->direction);
244 	}
245 	ctxt->mapped_sges = 0;
246 }
247 
248 void svc_rdma_put_context(struct svc_rdma_op_ctxt *ctxt, int free_pages)
249 {
250 	struct svcxprt_rdma *xprt = ctxt->xprt;
251 	int i;
252 
253 	if (free_pages)
254 		for (i = 0; i < ctxt->count; i++)
255 			put_page(ctxt->pages[i]);
256 
257 	spin_lock_bh(&xprt->sc_ctxt_lock);
258 	xprt->sc_ctxt_used--;
259 	list_add(&ctxt->free, &xprt->sc_ctxts);
260 	spin_unlock_bh(&xprt->sc_ctxt_lock);
261 }
262 
263 static void svc_rdma_destroy_ctxts(struct svcxprt_rdma *xprt)
264 {
265 	while (!list_empty(&xprt->sc_ctxts)) {
266 		struct svc_rdma_op_ctxt *ctxt;
267 
268 		ctxt = list_first_entry(&xprt->sc_ctxts,
269 					struct svc_rdma_op_ctxt, free);
270 		list_del(&ctxt->free);
271 		kfree(ctxt);
272 	}
273 }
274 
275 static struct svc_rdma_req_map *alloc_req_map(gfp_t flags)
276 {
277 	struct svc_rdma_req_map *map;
278 
279 	map = kmalloc(sizeof(*map), flags);
280 	if (map)
281 		INIT_LIST_HEAD(&map->free);
282 	return map;
283 }
284 
285 static bool svc_rdma_prealloc_maps(struct svcxprt_rdma *xprt)
286 {
287 	unsigned int i;
288 
289 	/* One for each receive buffer on this connection. */
290 	i = xprt->sc_max_requests;
291 
292 	while (i--) {
293 		struct svc_rdma_req_map *map;
294 
295 		map = alloc_req_map(GFP_KERNEL);
296 		if (!map) {
297 			dprintk("svcrdma: No memory for request map\n");
298 			return false;
299 		}
300 		list_add(&map->free, &xprt->sc_maps);
301 	}
302 	return true;
303 }
304 
305 struct svc_rdma_req_map *svc_rdma_get_req_map(struct svcxprt_rdma *xprt)
306 {
307 	struct svc_rdma_req_map *map = NULL;
308 
309 	spin_lock(&xprt->sc_map_lock);
310 	if (list_empty(&xprt->sc_maps))
311 		goto out_empty;
312 
313 	map = list_first_entry(&xprt->sc_maps,
314 			       struct svc_rdma_req_map, free);
315 	list_del_init(&map->free);
316 	spin_unlock(&xprt->sc_map_lock);
317 
318 out:
319 	map->count = 0;
320 	return map;
321 
322 out_empty:
323 	spin_unlock(&xprt->sc_map_lock);
324 
325 	/* Pre-allocation amount was incorrect */
326 	map = alloc_req_map(GFP_NOIO);
327 	if (map)
328 		goto out;
329 
330 	WARN_ONCE(1, "svcrdma: empty request map list?\n");
331 	return NULL;
332 }
333 
334 void svc_rdma_put_req_map(struct svcxprt_rdma *xprt,
335 			  struct svc_rdma_req_map *map)
336 {
337 	spin_lock(&xprt->sc_map_lock);
338 	list_add(&map->free, &xprt->sc_maps);
339 	spin_unlock(&xprt->sc_map_lock);
340 }
341 
342 static void svc_rdma_destroy_maps(struct svcxprt_rdma *xprt)
343 {
344 	while (!list_empty(&xprt->sc_maps)) {
345 		struct svc_rdma_req_map *map;
346 
347 		map = list_first_entry(&xprt->sc_maps,
348 				       struct svc_rdma_req_map, free);
349 		list_del(&map->free);
350 		kfree(map);
351 	}
352 }
353 
354 /* QP event handler */
355 static void qp_event_handler(struct ib_event *event, void *context)
356 {
357 	struct svc_xprt *xprt = context;
358 
359 	switch (event->event) {
360 	/* These are considered benign events */
361 	case IB_EVENT_PATH_MIG:
362 	case IB_EVENT_COMM_EST:
363 	case IB_EVENT_SQ_DRAINED:
364 	case IB_EVENT_QP_LAST_WQE_REACHED:
365 		dprintk("svcrdma: QP event %s (%d) received for QP=%p\n",
366 			ib_event_msg(event->event), event->event,
367 			event->element.qp);
368 		break;
369 	/* These are considered fatal events */
370 	case IB_EVENT_PATH_MIG_ERR:
371 	case IB_EVENT_QP_FATAL:
372 	case IB_EVENT_QP_REQ_ERR:
373 	case IB_EVENT_QP_ACCESS_ERR:
374 	case IB_EVENT_DEVICE_FATAL:
375 	default:
376 		dprintk("svcrdma: QP ERROR event %s (%d) received for QP=%p, "
377 			"closing transport\n",
378 			ib_event_msg(event->event), event->event,
379 			event->element.qp);
380 		set_bit(XPT_CLOSE, &xprt->xpt_flags);
381 		break;
382 	}
383 }
384 
385 /**
386  * svc_rdma_wc_receive - Invoked by RDMA provider for each polled Receive WC
387  * @cq:        completion queue
388  * @wc:        completed WR
389  *
390  */
391 static void svc_rdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc)
392 {
393 	struct svcxprt_rdma *xprt = cq->cq_context;
394 	struct ib_cqe *cqe = wc->wr_cqe;
395 	struct svc_rdma_op_ctxt *ctxt;
396 
397 	/* WARNING: Only wc->wr_cqe and wc->status are reliable */
398 	ctxt = container_of(cqe, struct svc_rdma_op_ctxt, cqe);
399 	svc_rdma_unmap_dma(ctxt);
400 
401 	if (wc->status != IB_WC_SUCCESS)
402 		goto flushed;
403 
404 	/* All wc fields are now known to be valid */
405 	ctxt->byte_len = wc->byte_len;
406 	spin_lock(&xprt->sc_rq_dto_lock);
407 	list_add_tail(&ctxt->dto_q, &xprt->sc_rq_dto_q);
408 	spin_unlock(&xprt->sc_rq_dto_lock);
409 
410 	set_bit(XPT_DATA, &xprt->sc_xprt.xpt_flags);
411 	if (test_bit(RDMAXPRT_CONN_PENDING, &xprt->sc_flags))
412 		goto out;
413 	svc_xprt_enqueue(&xprt->sc_xprt);
414 	goto out;
415 
416 flushed:
417 	if (wc->status != IB_WC_WR_FLUSH_ERR)
418 		pr_warn("svcrdma: receive: %s (%u/0x%x)\n",
419 			ib_wc_status_msg(wc->status),
420 			wc->status, wc->vendor_err);
421 	set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
422 	svc_rdma_put_context(ctxt, 1);
423 
424 out:
425 	svc_xprt_put(&xprt->sc_xprt);
426 }
427 
428 static void svc_rdma_send_wc_common(struct svcxprt_rdma *xprt,
429 				    struct ib_wc *wc,
430 				    const char *opname)
431 {
432 	if (wc->status != IB_WC_SUCCESS)
433 		goto err;
434 
435 out:
436 	atomic_inc(&xprt->sc_sq_avail);
437 	wake_up(&xprt->sc_send_wait);
438 	return;
439 
440 err:
441 	set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
442 	if (wc->status != IB_WC_WR_FLUSH_ERR)
443 		pr_err("svcrdma: %s: %s (%u/0x%x)\n",
444 		       opname, ib_wc_status_msg(wc->status),
445 		       wc->status, wc->vendor_err);
446 	goto out;
447 }
448 
449 static void svc_rdma_send_wc_common_put(struct ib_cq *cq, struct ib_wc *wc,
450 					const char *opname)
451 {
452 	struct svcxprt_rdma *xprt = cq->cq_context;
453 
454 	svc_rdma_send_wc_common(xprt, wc, opname);
455 	svc_xprt_put(&xprt->sc_xprt);
456 }
457 
458 /**
459  * svc_rdma_wc_send - Invoked by RDMA provider for each polled Send WC
460  * @cq:        completion queue
461  * @wc:        completed WR
462  *
463  */
464 void svc_rdma_wc_send(struct ib_cq *cq, struct ib_wc *wc)
465 {
466 	struct ib_cqe *cqe = wc->wr_cqe;
467 	struct svc_rdma_op_ctxt *ctxt;
468 
469 	svc_rdma_send_wc_common_put(cq, wc, "send");
470 
471 	ctxt = container_of(cqe, struct svc_rdma_op_ctxt, cqe);
472 	svc_rdma_unmap_dma(ctxt);
473 	svc_rdma_put_context(ctxt, 1);
474 }
475 
476 /**
477  * svc_rdma_wc_write - Invoked by RDMA provider for each polled Write WC
478  * @cq:        completion queue
479  * @wc:        completed WR
480  *
481  */
482 void svc_rdma_wc_write(struct ib_cq *cq, struct ib_wc *wc)
483 {
484 	struct ib_cqe *cqe = wc->wr_cqe;
485 	struct svc_rdma_op_ctxt *ctxt;
486 
487 	svc_rdma_send_wc_common_put(cq, wc, "write");
488 
489 	ctxt = container_of(cqe, struct svc_rdma_op_ctxt, cqe);
490 	svc_rdma_unmap_dma(ctxt);
491 	svc_rdma_put_context(ctxt, 0);
492 }
493 
494 /**
495  * svc_rdma_wc_reg - Invoked by RDMA provider for each polled FASTREG WC
496  * @cq:        completion queue
497  * @wc:        completed WR
498  *
499  */
500 void svc_rdma_wc_reg(struct ib_cq *cq, struct ib_wc *wc)
501 {
502 	svc_rdma_send_wc_common_put(cq, wc, "fastreg");
503 }
504 
505 /**
506  * svc_rdma_wc_read - Invoked by RDMA provider for each polled Read WC
507  * @cq:        completion queue
508  * @wc:        completed WR
509  *
510  */
511 void svc_rdma_wc_read(struct ib_cq *cq, struct ib_wc *wc)
512 {
513 	struct svcxprt_rdma *xprt = cq->cq_context;
514 	struct ib_cqe *cqe = wc->wr_cqe;
515 	struct svc_rdma_op_ctxt *ctxt;
516 
517 	svc_rdma_send_wc_common(xprt, wc, "read");
518 
519 	ctxt = container_of(cqe, struct svc_rdma_op_ctxt, cqe);
520 	svc_rdma_unmap_dma(ctxt);
521 	svc_rdma_put_frmr(xprt, ctxt->frmr);
522 
523 	if (test_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags)) {
524 		struct svc_rdma_op_ctxt *read_hdr;
525 
526 		read_hdr = ctxt->read_hdr;
527 		spin_lock(&xprt->sc_rq_dto_lock);
528 		list_add_tail(&read_hdr->dto_q,
529 			      &xprt->sc_read_complete_q);
530 		spin_unlock(&xprt->sc_rq_dto_lock);
531 
532 		set_bit(XPT_DATA, &xprt->sc_xprt.xpt_flags);
533 		svc_xprt_enqueue(&xprt->sc_xprt);
534 	}
535 
536 	svc_rdma_put_context(ctxt, 0);
537 	svc_xprt_put(&xprt->sc_xprt);
538 }
539 
540 /**
541  * svc_rdma_wc_inv - Invoked by RDMA provider for each polled LOCAL_INV WC
542  * @cq:        completion queue
543  * @wc:        completed WR
544  *
545  */
546 void svc_rdma_wc_inv(struct ib_cq *cq, struct ib_wc *wc)
547 {
548 	svc_rdma_send_wc_common_put(cq, wc, "localInv");
549 }
550 
551 static struct svcxprt_rdma *rdma_create_xprt(struct svc_serv *serv,
552 					     int listener)
553 {
554 	struct svcxprt_rdma *cma_xprt = kzalloc(sizeof *cma_xprt, GFP_KERNEL);
555 
556 	if (!cma_xprt)
557 		return NULL;
558 	svc_xprt_init(&init_net, &svc_rdma_class, &cma_xprt->sc_xprt, serv);
559 	INIT_LIST_HEAD(&cma_xprt->sc_accept_q);
560 	INIT_LIST_HEAD(&cma_xprt->sc_dto_q);
561 	INIT_LIST_HEAD(&cma_xprt->sc_rq_dto_q);
562 	INIT_LIST_HEAD(&cma_xprt->sc_read_complete_q);
563 	INIT_LIST_HEAD(&cma_xprt->sc_frmr_q);
564 	INIT_LIST_HEAD(&cma_xprt->sc_ctxts);
565 	INIT_LIST_HEAD(&cma_xprt->sc_maps);
566 	init_waitqueue_head(&cma_xprt->sc_send_wait);
567 
568 	spin_lock_init(&cma_xprt->sc_lock);
569 	spin_lock_init(&cma_xprt->sc_rq_dto_lock);
570 	spin_lock_init(&cma_xprt->sc_frmr_q_lock);
571 	spin_lock_init(&cma_xprt->sc_ctxt_lock);
572 	spin_lock_init(&cma_xprt->sc_map_lock);
573 
574 	if (listener)
575 		set_bit(XPT_LISTENER, &cma_xprt->sc_xprt.xpt_flags);
576 
577 	return cma_xprt;
578 }
579 
580 int svc_rdma_post_recv(struct svcxprt_rdma *xprt, gfp_t flags)
581 {
582 	struct ib_recv_wr recv_wr, *bad_recv_wr;
583 	struct svc_rdma_op_ctxt *ctxt;
584 	struct page *page;
585 	dma_addr_t pa;
586 	int sge_no;
587 	int buflen;
588 	int ret;
589 
590 	ctxt = svc_rdma_get_context(xprt);
591 	buflen = 0;
592 	ctxt->direction = DMA_FROM_DEVICE;
593 	ctxt->cqe.done = svc_rdma_wc_receive;
594 	for (sge_no = 0; buflen < xprt->sc_max_req_size; sge_no++) {
595 		if (sge_no >= xprt->sc_max_sge) {
596 			pr_err("svcrdma: Too many sges (%d)\n", sge_no);
597 			goto err_put_ctxt;
598 		}
599 		page = alloc_page(flags);
600 		if (!page)
601 			goto err_put_ctxt;
602 		ctxt->pages[sge_no] = page;
603 		pa = ib_dma_map_page(xprt->sc_cm_id->device,
604 				     page, 0, PAGE_SIZE,
605 				     DMA_FROM_DEVICE);
606 		if (ib_dma_mapping_error(xprt->sc_cm_id->device, pa))
607 			goto err_put_ctxt;
608 		svc_rdma_count_mappings(xprt, ctxt);
609 		ctxt->sge[sge_no].addr = pa;
610 		ctxt->sge[sge_no].length = PAGE_SIZE;
611 		ctxt->sge[sge_no].lkey = xprt->sc_pd->local_dma_lkey;
612 		ctxt->count = sge_no + 1;
613 		buflen += PAGE_SIZE;
614 	}
615 	recv_wr.next = NULL;
616 	recv_wr.sg_list = &ctxt->sge[0];
617 	recv_wr.num_sge = ctxt->count;
618 	recv_wr.wr_cqe = &ctxt->cqe;
619 
620 	svc_xprt_get(&xprt->sc_xprt);
621 	ret = ib_post_recv(xprt->sc_qp, &recv_wr, &bad_recv_wr);
622 	if (ret) {
623 		svc_rdma_unmap_dma(ctxt);
624 		svc_rdma_put_context(ctxt, 1);
625 		svc_xprt_put(&xprt->sc_xprt);
626 	}
627 	return ret;
628 
629  err_put_ctxt:
630 	svc_rdma_unmap_dma(ctxt);
631 	svc_rdma_put_context(ctxt, 1);
632 	return -ENOMEM;
633 }
634 
635 int svc_rdma_repost_recv(struct svcxprt_rdma *xprt, gfp_t flags)
636 {
637 	int ret = 0;
638 
639 	ret = svc_rdma_post_recv(xprt, flags);
640 	if (ret) {
641 		pr_err("svcrdma: could not post a receive buffer, err=%d.\n",
642 		       ret);
643 		pr_err("svcrdma: closing transport %p.\n", xprt);
644 		set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
645 		ret = -ENOTCONN;
646 	}
647 	return ret;
648 }
649 
650 static void
651 svc_rdma_parse_connect_private(struct svcxprt_rdma *newxprt,
652 			       struct rdma_conn_param *param)
653 {
654 	const struct rpcrdma_connect_private *pmsg = param->private_data;
655 
656 	if (pmsg &&
657 	    pmsg->cp_magic == rpcrdma_cmp_magic &&
658 	    pmsg->cp_version == RPCRDMA_CMP_VERSION) {
659 		newxprt->sc_snd_w_inv = pmsg->cp_flags &
660 					RPCRDMA_CMP_F_SND_W_INV_OK;
661 
662 		dprintk("svcrdma: client send_size %u, recv_size %u "
663 			"remote inv %ssupported\n",
664 			rpcrdma_decode_buffer_size(pmsg->cp_send_size),
665 			rpcrdma_decode_buffer_size(pmsg->cp_recv_size),
666 			newxprt->sc_snd_w_inv ? "" : "un");
667 	}
668 }
669 
670 /*
671  * This function handles the CONNECT_REQUEST event on a listening
672  * endpoint. It is passed the cma_id for the _new_ connection. The context in
673  * this cma_id is inherited from the listening cma_id and is the svc_xprt
674  * structure for the listening endpoint.
675  *
676  * This function creates a new xprt for the new connection and enqueues it on
677  * the accept queue for the listent xprt. When the listen thread is kicked, it
678  * will call the recvfrom method on the listen xprt which will accept the new
679  * connection.
680  */
681 static void handle_connect_req(struct rdma_cm_id *new_cma_id,
682 			       struct rdma_conn_param *param)
683 {
684 	struct svcxprt_rdma *listen_xprt = new_cma_id->context;
685 	struct svcxprt_rdma *newxprt;
686 	struct sockaddr *sa;
687 
688 	/* Create a new transport */
689 	newxprt = rdma_create_xprt(listen_xprt->sc_xprt.xpt_server, 0);
690 	if (!newxprt) {
691 		dprintk("svcrdma: failed to create new transport\n");
692 		return;
693 	}
694 	newxprt->sc_cm_id = new_cma_id;
695 	new_cma_id->context = newxprt;
696 	dprintk("svcrdma: Creating newxprt=%p, cm_id=%p, listenxprt=%p\n",
697 		newxprt, newxprt->sc_cm_id, listen_xprt);
698 	svc_rdma_parse_connect_private(newxprt, param);
699 
700 	/* Save client advertised inbound read limit for use later in accept. */
701 	newxprt->sc_ord = param->initiator_depth;
702 
703 	/* Set the local and remote addresses in the transport */
704 	sa = (struct sockaddr *)&newxprt->sc_cm_id->route.addr.dst_addr;
705 	svc_xprt_set_remote(&newxprt->sc_xprt, sa, svc_addr_len(sa));
706 	sa = (struct sockaddr *)&newxprt->sc_cm_id->route.addr.src_addr;
707 	svc_xprt_set_local(&newxprt->sc_xprt, sa, svc_addr_len(sa));
708 
709 	/*
710 	 * Enqueue the new transport on the accept queue of the listening
711 	 * transport
712 	 */
713 	spin_lock_bh(&listen_xprt->sc_lock);
714 	list_add_tail(&newxprt->sc_accept_q, &listen_xprt->sc_accept_q);
715 	spin_unlock_bh(&listen_xprt->sc_lock);
716 
717 	set_bit(XPT_CONN, &listen_xprt->sc_xprt.xpt_flags);
718 	svc_xprt_enqueue(&listen_xprt->sc_xprt);
719 }
720 
721 /*
722  * Handles events generated on the listening endpoint. These events will be
723  * either be incoming connect requests or adapter removal  events.
724  */
725 static int rdma_listen_handler(struct rdma_cm_id *cma_id,
726 			       struct rdma_cm_event *event)
727 {
728 	struct svcxprt_rdma *xprt = cma_id->context;
729 	int ret = 0;
730 
731 	switch (event->event) {
732 	case RDMA_CM_EVENT_CONNECT_REQUEST:
733 		dprintk("svcrdma: Connect request on cma_id=%p, xprt = %p, "
734 			"event = %s (%d)\n", cma_id, cma_id->context,
735 			rdma_event_msg(event->event), event->event);
736 		handle_connect_req(cma_id, &event->param.conn);
737 		break;
738 
739 	case RDMA_CM_EVENT_ESTABLISHED:
740 		/* Accept complete */
741 		dprintk("svcrdma: Connection completed on LISTEN xprt=%p, "
742 			"cm_id=%p\n", xprt, cma_id);
743 		break;
744 
745 	case RDMA_CM_EVENT_DEVICE_REMOVAL:
746 		dprintk("svcrdma: Device removal xprt=%p, cm_id=%p\n",
747 			xprt, cma_id);
748 		if (xprt)
749 			set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
750 		break;
751 
752 	default:
753 		dprintk("svcrdma: Unexpected event on listening endpoint %p, "
754 			"event = %s (%d)\n", cma_id,
755 			rdma_event_msg(event->event), event->event);
756 		break;
757 	}
758 
759 	return ret;
760 }
761 
762 static int rdma_cma_handler(struct rdma_cm_id *cma_id,
763 			    struct rdma_cm_event *event)
764 {
765 	struct svc_xprt *xprt = cma_id->context;
766 	struct svcxprt_rdma *rdma =
767 		container_of(xprt, struct svcxprt_rdma, sc_xprt);
768 	switch (event->event) {
769 	case RDMA_CM_EVENT_ESTABLISHED:
770 		/* Accept complete */
771 		svc_xprt_get(xprt);
772 		dprintk("svcrdma: Connection completed on DTO xprt=%p, "
773 			"cm_id=%p\n", xprt, cma_id);
774 		clear_bit(RDMAXPRT_CONN_PENDING, &rdma->sc_flags);
775 		svc_xprt_enqueue(xprt);
776 		break;
777 	case RDMA_CM_EVENT_DISCONNECTED:
778 		dprintk("svcrdma: Disconnect on DTO xprt=%p, cm_id=%p\n",
779 			xprt, cma_id);
780 		if (xprt) {
781 			set_bit(XPT_CLOSE, &xprt->xpt_flags);
782 			svc_xprt_enqueue(xprt);
783 			svc_xprt_put(xprt);
784 		}
785 		break;
786 	case RDMA_CM_EVENT_DEVICE_REMOVAL:
787 		dprintk("svcrdma: Device removal cma_id=%p, xprt = %p, "
788 			"event = %s (%d)\n", cma_id, xprt,
789 			rdma_event_msg(event->event), event->event);
790 		if (xprt) {
791 			set_bit(XPT_CLOSE, &xprt->xpt_flags);
792 			svc_xprt_enqueue(xprt);
793 			svc_xprt_put(xprt);
794 		}
795 		break;
796 	default:
797 		dprintk("svcrdma: Unexpected event on DTO endpoint %p, "
798 			"event = %s (%d)\n", cma_id,
799 			rdma_event_msg(event->event), event->event);
800 		break;
801 	}
802 	return 0;
803 }
804 
805 /*
806  * Create a listening RDMA service endpoint.
807  */
808 static struct svc_xprt *svc_rdma_create(struct svc_serv *serv,
809 					struct net *net,
810 					struct sockaddr *sa, int salen,
811 					int flags)
812 {
813 	struct rdma_cm_id *listen_id;
814 	struct svcxprt_rdma *cma_xprt;
815 	int ret;
816 
817 	dprintk("svcrdma: Creating RDMA socket\n");
818 	if ((sa->sa_family != AF_INET) && (sa->sa_family != AF_INET6)) {
819 		dprintk("svcrdma: Address family %d is not supported.\n", sa->sa_family);
820 		return ERR_PTR(-EAFNOSUPPORT);
821 	}
822 	cma_xprt = rdma_create_xprt(serv, 1);
823 	if (!cma_xprt)
824 		return ERR_PTR(-ENOMEM);
825 
826 	listen_id = rdma_create_id(&init_net, rdma_listen_handler, cma_xprt,
827 				   RDMA_PS_TCP, IB_QPT_RC);
828 	if (IS_ERR(listen_id)) {
829 		ret = PTR_ERR(listen_id);
830 		dprintk("svcrdma: rdma_create_id failed = %d\n", ret);
831 		goto err0;
832 	}
833 
834 	/* Allow both IPv4 and IPv6 sockets to bind a single port
835 	 * at the same time.
836 	 */
837 #if IS_ENABLED(CONFIG_IPV6)
838 	ret = rdma_set_afonly(listen_id, 1);
839 	if (ret) {
840 		dprintk("svcrdma: rdma_set_afonly failed = %d\n", ret);
841 		goto err1;
842 	}
843 #endif
844 	ret = rdma_bind_addr(listen_id, sa);
845 	if (ret) {
846 		dprintk("svcrdma: rdma_bind_addr failed = %d\n", ret);
847 		goto err1;
848 	}
849 	cma_xprt->sc_cm_id = listen_id;
850 
851 	ret = rdma_listen(listen_id, RPCRDMA_LISTEN_BACKLOG);
852 	if (ret) {
853 		dprintk("svcrdma: rdma_listen failed = %d\n", ret);
854 		goto err1;
855 	}
856 
857 	/*
858 	 * We need to use the address from the cm_id in case the
859 	 * caller specified 0 for the port number.
860 	 */
861 	sa = (struct sockaddr *)&cma_xprt->sc_cm_id->route.addr.src_addr;
862 	svc_xprt_set_local(&cma_xprt->sc_xprt, sa, salen);
863 
864 	return &cma_xprt->sc_xprt;
865 
866  err1:
867 	rdma_destroy_id(listen_id);
868  err0:
869 	kfree(cma_xprt);
870 	return ERR_PTR(ret);
871 }
872 
873 static struct svc_rdma_fastreg_mr *rdma_alloc_frmr(struct svcxprt_rdma *xprt)
874 {
875 	struct ib_mr *mr;
876 	struct scatterlist *sg;
877 	struct svc_rdma_fastreg_mr *frmr;
878 	u32 num_sg;
879 
880 	frmr = kmalloc(sizeof(*frmr), GFP_KERNEL);
881 	if (!frmr)
882 		goto err;
883 
884 	num_sg = min_t(u32, RPCSVC_MAXPAGES, xprt->sc_frmr_pg_list_len);
885 	mr = ib_alloc_mr(xprt->sc_pd, IB_MR_TYPE_MEM_REG, num_sg);
886 	if (IS_ERR(mr))
887 		goto err_free_frmr;
888 
889 	sg = kcalloc(RPCSVC_MAXPAGES, sizeof(*sg), GFP_KERNEL);
890 	if (!sg)
891 		goto err_free_mr;
892 
893 	sg_init_table(sg, RPCSVC_MAXPAGES);
894 
895 	frmr->mr = mr;
896 	frmr->sg = sg;
897 	INIT_LIST_HEAD(&frmr->frmr_list);
898 	return frmr;
899 
900  err_free_mr:
901 	ib_dereg_mr(mr);
902  err_free_frmr:
903 	kfree(frmr);
904  err:
905 	return ERR_PTR(-ENOMEM);
906 }
907 
908 static void rdma_dealloc_frmr_q(struct svcxprt_rdma *xprt)
909 {
910 	struct svc_rdma_fastreg_mr *frmr;
911 
912 	while (!list_empty(&xprt->sc_frmr_q)) {
913 		frmr = list_entry(xprt->sc_frmr_q.next,
914 				  struct svc_rdma_fastreg_mr, frmr_list);
915 		list_del_init(&frmr->frmr_list);
916 		kfree(frmr->sg);
917 		ib_dereg_mr(frmr->mr);
918 		kfree(frmr);
919 	}
920 }
921 
922 struct svc_rdma_fastreg_mr *svc_rdma_get_frmr(struct svcxprt_rdma *rdma)
923 {
924 	struct svc_rdma_fastreg_mr *frmr = NULL;
925 
926 	spin_lock_bh(&rdma->sc_frmr_q_lock);
927 	if (!list_empty(&rdma->sc_frmr_q)) {
928 		frmr = list_entry(rdma->sc_frmr_q.next,
929 				  struct svc_rdma_fastreg_mr, frmr_list);
930 		list_del_init(&frmr->frmr_list);
931 		frmr->sg_nents = 0;
932 	}
933 	spin_unlock_bh(&rdma->sc_frmr_q_lock);
934 	if (frmr)
935 		return frmr;
936 
937 	return rdma_alloc_frmr(rdma);
938 }
939 
940 void svc_rdma_put_frmr(struct svcxprt_rdma *rdma,
941 		       struct svc_rdma_fastreg_mr *frmr)
942 {
943 	if (frmr) {
944 		ib_dma_unmap_sg(rdma->sc_cm_id->device,
945 				frmr->sg, frmr->sg_nents, frmr->direction);
946 		spin_lock_bh(&rdma->sc_frmr_q_lock);
947 		WARN_ON_ONCE(!list_empty(&frmr->frmr_list));
948 		list_add(&frmr->frmr_list, &rdma->sc_frmr_q);
949 		spin_unlock_bh(&rdma->sc_frmr_q_lock);
950 	}
951 }
952 
953 /*
954  * This is the xpo_recvfrom function for listening endpoints. Its
955  * purpose is to accept incoming connections. The CMA callback handler
956  * has already created a new transport and attached it to the new CMA
957  * ID.
958  *
959  * There is a queue of pending connections hung on the listening
960  * transport. This queue contains the new svc_xprt structure. This
961  * function takes svc_xprt structures off the accept_q and completes
962  * the connection.
963  */
964 static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
965 {
966 	struct svcxprt_rdma *listen_rdma;
967 	struct svcxprt_rdma *newxprt = NULL;
968 	struct rdma_conn_param conn_param;
969 	struct rpcrdma_connect_private pmsg;
970 	struct ib_qp_init_attr qp_attr;
971 	struct ib_device *dev;
972 	struct sockaddr *sap;
973 	unsigned int i;
974 	int ret = 0;
975 
976 	listen_rdma = container_of(xprt, struct svcxprt_rdma, sc_xprt);
977 	clear_bit(XPT_CONN, &xprt->xpt_flags);
978 	/* Get the next entry off the accept list */
979 	spin_lock_bh(&listen_rdma->sc_lock);
980 	if (!list_empty(&listen_rdma->sc_accept_q)) {
981 		newxprt = list_entry(listen_rdma->sc_accept_q.next,
982 				     struct svcxprt_rdma, sc_accept_q);
983 		list_del_init(&newxprt->sc_accept_q);
984 	}
985 	if (!list_empty(&listen_rdma->sc_accept_q))
986 		set_bit(XPT_CONN, &listen_rdma->sc_xprt.xpt_flags);
987 	spin_unlock_bh(&listen_rdma->sc_lock);
988 	if (!newxprt)
989 		return NULL;
990 
991 	dprintk("svcrdma: newxprt from accept queue = %p, cm_id=%p\n",
992 		newxprt, newxprt->sc_cm_id);
993 
994 	dev = newxprt->sc_cm_id->device;
995 
996 	/* Qualify the transport resource defaults with the
997 	 * capabilities of this particular device */
998 	newxprt->sc_max_sge = min((size_t)dev->attrs.max_sge,
999 				  (size_t)RPCSVC_MAXPAGES);
1000 	newxprt->sc_max_sge_rd = min_t(size_t, dev->attrs.max_sge_rd,
1001 				       RPCSVC_MAXPAGES);
1002 	newxprt->sc_max_req_size = svcrdma_max_req_size;
1003 	newxprt->sc_max_requests = min_t(u32, dev->attrs.max_qp_wr,
1004 					 svcrdma_max_requests);
1005 	newxprt->sc_max_bc_requests = min_t(u32, dev->attrs.max_qp_wr,
1006 					    svcrdma_max_bc_requests);
1007 	newxprt->sc_rq_depth = newxprt->sc_max_requests +
1008 			       newxprt->sc_max_bc_requests;
1009 	newxprt->sc_sq_depth = RPCRDMA_SQ_DEPTH_MULT * newxprt->sc_rq_depth;
1010 	atomic_set(&newxprt->sc_sq_avail, newxprt->sc_sq_depth);
1011 
1012 	if (!svc_rdma_prealloc_ctxts(newxprt))
1013 		goto errout;
1014 	if (!svc_rdma_prealloc_maps(newxprt))
1015 		goto errout;
1016 
1017 	/*
1018 	 * Limit ORD based on client limit, local device limit, and
1019 	 * configured svcrdma limit.
1020 	 */
1021 	newxprt->sc_ord = min_t(size_t, dev->attrs.max_qp_rd_atom, newxprt->sc_ord);
1022 	newxprt->sc_ord = min_t(size_t,	svcrdma_ord, newxprt->sc_ord);
1023 
1024 	newxprt->sc_pd = ib_alloc_pd(dev, 0);
1025 	if (IS_ERR(newxprt->sc_pd)) {
1026 		dprintk("svcrdma: error creating PD for connect request\n");
1027 		goto errout;
1028 	}
1029 	newxprt->sc_sq_cq = ib_alloc_cq(dev, newxprt, newxprt->sc_sq_depth,
1030 					0, IB_POLL_SOFTIRQ);
1031 	if (IS_ERR(newxprt->sc_sq_cq)) {
1032 		dprintk("svcrdma: error creating SQ CQ for connect request\n");
1033 		goto errout;
1034 	}
1035 	newxprt->sc_rq_cq = ib_alloc_cq(dev, newxprt, newxprt->sc_rq_depth,
1036 					0, IB_POLL_SOFTIRQ);
1037 	if (IS_ERR(newxprt->sc_rq_cq)) {
1038 		dprintk("svcrdma: error creating RQ CQ for connect request\n");
1039 		goto errout;
1040 	}
1041 
1042 	memset(&qp_attr, 0, sizeof qp_attr);
1043 	qp_attr.event_handler = qp_event_handler;
1044 	qp_attr.qp_context = &newxprt->sc_xprt;
1045 	qp_attr.cap.max_send_wr = newxprt->sc_sq_depth;
1046 	qp_attr.cap.max_recv_wr = newxprt->sc_rq_depth;
1047 	qp_attr.cap.max_send_sge = newxprt->sc_max_sge;
1048 	qp_attr.cap.max_recv_sge = newxprt->sc_max_sge;
1049 	qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
1050 	qp_attr.qp_type = IB_QPT_RC;
1051 	qp_attr.send_cq = newxprt->sc_sq_cq;
1052 	qp_attr.recv_cq = newxprt->sc_rq_cq;
1053 	dprintk("svcrdma: newxprt->sc_cm_id=%p, newxprt->sc_pd=%p\n",
1054 		newxprt->sc_cm_id, newxprt->sc_pd);
1055 	dprintk("    cap.max_send_wr = %d, cap.max_recv_wr = %d\n",
1056 		qp_attr.cap.max_send_wr, qp_attr.cap.max_recv_wr);
1057 	dprintk("    cap.max_send_sge = %d, cap.max_recv_sge = %d\n",
1058 		qp_attr.cap.max_send_sge, qp_attr.cap.max_recv_sge);
1059 
1060 	ret = rdma_create_qp(newxprt->sc_cm_id, newxprt->sc_pd, &qp_attr);
1061 	if (ret) {
1062 		dprintk("svcrdma: failed to create QP, ret=%d\n", ret);
1063 		goto errout;
1064 	}
1065 	newxprt->sc_qp = newxprt->sc_cm_id->qp;
1066 
1067 	/*
1068 	 * Use the most secure set of MR resources based on the
1069 	 * transport type and available memory management features in
1070 	 * the device. Here's the table implemented below:
1071 	 *
1072 	 *		Fast	Global	DMA	Remote WR
1073 	 *		Reg	LKEY	MR	Access
1074 	 *		Sup'd	Sup'd	Needed	Needed
1075 	 *
1076 	 * IWARP	N	N	Y	Y
1077 	 *		N	Y	Y	Y
1078 	 *		Y	N	Y	N
1079 	 *		Y	Y	N	-
1080 	 *
1081 	 * IB		N	N	Y	N
1082 	 *		N	Y	N	-
1083 	 *		Y	N	Y	N
1084 	 *		Y	Y	N	-
1085 	 *
1086 	 * NB:	iWARP requires remote write access for the data sink
1087 	 *	of an RDMA_READ. IB does not.
1088 	 */
1089 	newxprt->sc_reader = rdma_read_chunk_lcl;
1090 	if (dev->attrs.device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS) {
1091 		newxprt->sc_frmr_pg_list_len =
1092 			dev->attrs.max_fast_reg_page_list_len;
1093 		newxprt->sc_dev_caps |= SVCRDMA_DEVCAP_FAST_REG;
1094 		newxprt->sc_reader = rdma_read_chunk_frmr;
1095 	} else
1096 		newxprt->sc_snd_w_inv = false;
1097 
1098 	/*
1099 	 * Determine if a DMA MR is required and if so, what privs are required
1100 	 */
1101 	if (!rdma_protocol_iwarp(dev, newxprt->sc_cm_id->port_num) &&
1102 	    !rdma_ib_or_roce(dev, newxprt->sc_cm_id->port_num))
1103 		goto errout;
1104 
1105 	if (rdma_protocol_iwarp(dev, newxprt->sc_cm_id->port_num))
1106 		newxprt->sc_dev_caps |= SVCRDMA_DEVCAP_READ_W_INV;
1107 
1108 	/* Post receive buffers */
1109 	for (i = 0; i < newxprt->sc_max_requests; i++) {
1110 		ret = svc_rdma_post_recv(newxprt, GFP_KERNEL);
1111 		if (ret) {
1112 			dprintk("svcrdma: failure posting receive buffers\n");
1113 			goto errout;
1114 		}
1115 	}
1116 
1117 	/* Swap out the handler */
1118 	newxprt->sc_cm_id->event_handler = rdma_cma_handler;
1119 
1120 	/* Construct RDMA-CM private message */
1121 	pmsg.cp_magic = rpcrdma_cmp_magic;
1122 	pmsg.cp_version = RPCRDMA_CMP_VERSION;
1123 	pmsg.cp_flags = 0;
1124 	pmsg.cp_send_size = pmsg.cp_recv_size =
1125 		rpcrdma_encode_buffer_size(newxprt->sc_max_req_size);
1126 
1127 	/* Accept Connection */
1128 	set_bit(RDMAXPRT_CONN_PENDING, &newxprt->sc_flags);
1129 	memset(&conn_param, 0, sizeof conn_param);
1130 	conn_param.responder_resources = 0;
1131 	conn_param.initiator_depth = newxprt->sc_ord;
1132 	conn_param.private_data = &pmsg;
1133 	conn_param.private_data_len = sizeof(pmsg);
1134 	ret = rdma_accept(newxprt->sc_cm_id, &conn_param);
1135 	if (ret) {
1136 		dprintk("svcrdma: failed to accept new connection, ret=%d\n",
1137 		       ret);
1138 		goto errout;
1139 	}
1140 
1141 	dprintk("svcrdma: new connection %p accepted:\n", newxprt);
1142 	sap = (struct sockaddr *)&newxprt->sc_cm_id->route.addr.src_addr;
1143 	dprintk("    local address   : %pIS:%u\n", sap, rpc_get_port(sap));
1144 	sap = (struct sockaddr *)&newxprt->sc_cm_id->route.addr.dst_addr;
1145 	dprintk("    remote address  : %pIS:%u\n", sap, rpc_get_port(sap));
1146 	dprintk("    max_sge         : %d\n", newxprt->sc_max_sge);
1147 	dprintk("    max_sge_rd      : %d\n", newxprt->sc_max_sge_rd);
1148 	dprintk("    sq_depth        : %d\n", newxprt->sc_sq_depth);
1149 	dprintk("    max_requests    : %d\n", newxprt->sc_max_requests);
1150 	dprintk("    ord             : %d\n", newxprt->sc_ord);
1151 
1152 	return &newxprt->sc_xprt;
1153 
1154  errout:
1155 	dprintk("svcrdma: failure accepting new connection rc=%d.\n", ret);
1156 	/* Take a reference in case the DTO handler runs */
1157 	svc_xprt_get(&newxprt->sc_xprt);
1158 	if (newxprt->sc_qp && !IS_ERR(newxprt->sc_qp))
1159 		ib_destroy_qp(newxprt->sc_qp);
1160 	rdma_destroy_id(newxprt->sc_cm_id);
1161 	/* This call to put will destroy the transport */
1162 	svc_xprt_put(&newxprt->sc_xprt);
1163 	return NULL;
1164 }
1165 
1166 static void svc_rdma_release_rqst(struct svc_rqst *rqstp)
1167 {
1168 }
1169 
1170 /*
1171  * When connected, an svc_xprt has at least two references:
1172  *
1173  * - A reference held by the cm_id between the ESTABLISHED and
1174  *   DISCONNECTED events. If the remote peer disconnected first, this
1175  *   reference could be gone.
1176  *
1177  * - A reference held by the svc_recv code that called this function
1178  *   as part of close processing.
1179  *
1180  * At a minimum one references should still be held.
1181  */
1182 static void svc_rdma_detach(struct svc_xprt *xprt)
1183 {
1184 	struct svcxprt_rdma *rdma =
1185 		container_of(xprt, struct svcxprt_rdma, sc_xprt);
1186 	dprintk("svc: svc_rdma_detach(%p)\n", xprt);
1187 
1188 	/* Disconnect and flush posted WQE */
1189 	rdma_disconnect(rdma->sc_cm_id);
1190 }
1191 
1192 static void __svc_rdma_free(struct work_struct *work)
1193 {
1194 	struct svcxprt_rdma *rdma =
1195 		container_of(work, struct svcxprt_rdma, sc_work);
1196 	struct svc_xprt *xprt = &rdma->sc_xprt;
1197 
1198 	dprintk("svcrdma: %s(%p)\n", __func__, rdma);
1199 
1200 	if (rdma->sc_qp && !IS_ERR(rdma->sc_qp))
1201 		ib_drain_qp(rdma->sc_qp);
1202 
1203 	/* We should only be called from kref_put */
1204 	if (kref_read(&xprt->xpt_ref) != 0)
1205 		pr_err("svcrdma: sc_xprt still in use? (%d)\n",
1206 		       kref_read(&xprt->xpt_ref));
1207 
1208 	/*
1209 	 * Destroy queued, but not processed read completions. Note
1210 	 * that this cleanup has to be done before destroying the
1211 	 * cm_id because the device ptr is needed to unmap the dma in
1212 	 * svc_rdma_put_context.
1213 	 */
1214 	while (!list_empty(&rdma->sc_read_complete_q)) {
1215 		struct svc_rdma_op_ctxt *ctxt;
1216 		ctxt = list_entry(rdma->sc_read_complete_q.next,
1217 				  struct svc_rdma_op_ctxt,
1218 				  dto_q);
1219 		list_del_init(&ctxt->dto_q);
1220 		svc_rdma_put_context(ctxt, 1);
1221 	}
1222 
1223 	/* Destroy queued, but not processed recv completions */
1224 	while (!list_empty(&rdma->sc_rq_dto_q)) {
1225 		struct svc_rdma_op_ctxt *ctxt;
1226 		ctxt = list_entry(rdma->sc_rq_dto_q.next,
1227 				  struct svc_rdma_op_ctxt,
1228 				  dto_q);
1229 		list_del_init(&ctxt->dto_q);
1230 		svc_rdma_put_context(ctxt, 1);
1231 	}
1232 
1233 	/* Warn if we leaked a resource or under-referenced */
1234 	if (rdma->sc_ctxt_used != 0)
1235 		pr_err("svcrdma: ctxt still in use? (%d)\n",
1236 		       rdma->sc_ctxt_used);
1237 
1238 	/* Final put of backchannel client transport */
1239 	if (xprt->xpt_bc_xprt) {
1240 		xprt_put(xprt->xpt_bc_xprt);
1241 		xprt->xpt_bc_xprt = NULL;
1242 	}
1243 
1244 	rdma_dealloc_frmr_q(rdma);
1245 	svc_rdma_destroy_ctxts(rdma);
1246 	svc_rdma_destroy_maps(rdma);
1247 
1248 	/* Destroy the QP if present (not a listener) */
1249 	if (rdma->sc_qp && !IS_ERR(rdma->sc_qp))
1250 		ib_destroy_qp(rdma->sc_qp);
1251 
1252 	if (rdma->sc_sq_cq && !IS_ERR(rdma->sc_sq_cq))
1253 		ib_free_cq(rdma->sc_sq_cq);
1254 
1255 	if (rdma->sc_rq_cq && !IS_ERR(rdma->sc_rq_cq))
1256 		ib_free_cq(rdma->sc_rq_cq);
1257 
1258 	if (rdma->sc_pd && !IS_ERR(rdma->sc_pd))
1259 		ib_dealloc_pd(rdma->sc_pd);
1260 
1261 	/* Destroy the CM ID */
1262 	rdma_destroy_id(rdma->sc_cm_id);
1263 
1264 	kfree(rdma);
1265 }
1266 
1267 static void svc_rdma_free(struct svc_xprt *xprt)
1268 {
1269 	struct svcxprt_rdma *rdma =
1270 		container_of(xprt, struct svcxprt_rdma, sc_xprt);
1271 	INIT_WORK(&rdma->sc_work, __svc_rdma_free);
1272 	queue_work(svc_rdma_wq, &rdma->sc_work);
1273 }
1274 
1275 static int svc_rdma_has_wspace(struct svc_xprt *xprt)
1276 {
1277 	struct svcxprt_rdma *rdma =
1278 		container_of(xprt, struct svcxprt_rdma, sc_xprt);
1279 
1280 	/*
1281 	 * If there are already waiters on the SQ,
1282 	 * return false.
1283 	 */
1284 	if (waitqueue_active(&rdma->sc_send_wait))
1285 		return 0;
1286 
1287 	/* Otherwise return true. */
1288 	return 1;
1289 }
1290 
1291 static int svc_rdma_secure_port(struct svc_rqst *rqstp)
1292 {
1293 	return 1;
1294 }
1295 
1296 static void svc_rdma_kill_temp_xprt(struct svc_xprt *xprt)
1297 {
1298 }
1299 
1300 int svc_rdma_send(struct svcxprt_rdma *xprt, struct ib_send_wr *wr)
1301 {
1302 	struct ib_send_wr *bad_wr, *n_wr;
1303 	int wr_count;
1304 	int i;
1305 	int ret;
1306 
1307 	if (test_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags))
1308 		return -ENOTCONN;
1309 
1310 	wr_count = 1;
1311 	for (n_wr = wr->next; n_wr; n_wr = n_wr->next)
1312 		wr_count++;
1313 
1314 	/* If the SQ is full, wait until an SQ entry is available */
1315 	while (1) {
1316 		if ((atomic_sub_return(wr_count, &xprt->sc_sq_avail) < 0)) {
1317 			atomic_inc(&rdma_stat_sq_starve);
1318 
1319 			/* Wait until SQ WR available if SQ still full */
1320 			atomic_add(wr_count, &xprt->sc_sq_avail);
1321 			wait_event(xprt->sc_send_wait,
1322 				   atomic_read(&xprt->sc_sq_avail) > wr_count);
1323 			if (test_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags))
1324 				return -ENOTCONN;
1325 			continue;
1326 		}
1327 		/* Take a transport ref for each WR posted */
1328 		for (i = 0; i < wr_count; i++)
1329 			svc_xprt_get(&xprt->sc_xprt);
1330 
1331 		/* Bump used SQ WR count and post */
1332 		ret = ib_post_send(xprt->sc_qp, wr, &bad_wr);
1333 		if (ret) {
1334 			set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
1335 			for (i = 0; i < wr_count; i ++)
1336 				svc_xprt_put(&xprt->sc_xprt);
1337 			dprintk("svcrdma: failed to post SQ WR rc=%d\n", ret);
1338 			dprintk("    sc_sq_avail=%d, sc_sq_depth=%d\n",
1339 				atomic_read(&xprt->sc_sq_avail),
1340 				xprt->sc_sq_depth);
1341 			wake_up(&xprt->sc_send_wait);
1342 		}
1343 		break;
1344 	}
1345 	return ret;
1346 }
1347