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/debug.h>
45 #include <linux/sunrpc/rpc_rdma.h>
46 #include <linux/interrupt.h>
47 #include <linux/sched.h>
48 #include <linux/slab.h>
49 #include <linux/spinlock.h>
50 #include <linux/workqueue.h>
51 #include <rdma/ib_verbs.h>
52 #include <rdma/rdma_cm.h>
53 #include <linux/sunrpc/svc_rdma.h>
54 #include <linux/export.h>
55 #include "xprt_rdma.h"
56 
57 #define RPCDBG_FACILITY	RPCDBG_SVCXPRT
58 
59 static struct svcxprt_rdma *rdma_create_xprt(struct svc_serv *, int);
60 static struct svc_xprt *svc_rdma_create(struct svc_serv *serv,
61 					struct net *net,
62 					struct sockaddr *sa, int salen,
63 					int flags);
64 static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt);
65 static void svc_rdma_release_rqst(struct svc_rqst *);
66 static void dto_tasklet_func(unsigned long data);
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 rq_cq_reap(struct svcxprt_rdma *xprt);
72 static void sq_cq_reap(struct svcxprt_rdma *xprt);
73 
74 static DECLARE_TASKLET(dto_tasklet, dto_tasklet_func, 0UL);
75 static DEFINE_SPINLOCK(dto_lock);
76 static LIST_HEAD(dto_xprt_q);
77 
78 static struct svc_xprt_ops svc_rdma_ops = {
79 	.xpo_create = svc_rdma_create,
80 	.xpo_recvfrom = svc_rdma_recvfrom,
81 	.xpo_sendto = svc_rdma_sendto,
82 	.xpo_release_rqst = svc_rdma_release_rqst,
83 	.xpo_detach = svc_rdma_detach,
84 	.xpo_free = svc_rdma_free,
85 	.xpo_prep_reply_hdr = svc_rdma_prep_reply_hdr,
86 	.xpo_has_wspace = svc_rdma_has_wspace,
87 	.xpo_accept = svc_rdma_accept,
88 	.xpo_secure_port = svc_rdma_secure_port,
89 };
90 
91 struct svc_xprt_class svc_rdma_class = {
92 	.xcl_name = "rdma",
93 	.xcl_owner = THIS_MODULE,
94 	.xcl_ops = &svc_rdma_ops,
95 	.xcl_max_payload = RPCSVC_MAXPAYLOAD_RDMA,
96 	.xcl_ident = XPRT_TRANSPORT_RDMA,
97 };
98 
99 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
100 static struct svc_xprt *svc_rdma_bc_create(struct svc_serv *, struct net *,
101 					   struct sockaddr *, int, int);
102 static void svc_rdma_bc_detach(struct svc_xprt *);
103 static void svc_rdma_bc_free(struct svc_xprt *);
104 
105 static struct svc_xprt_ops svc_rdma_bc_ops = {
106 	.xpo_create = svc_rdma_bc_create,
107 	.xpo_detach = svc_rdma_bc_detach,
108 	.xpo_free = svc_rdma_bc_free,
109 	.xpo_prep_reply_hdr = svc_rdma_prep_reply_hdr,
110 	.xpo_secure_port = svc_rdma_secure_port,
111 };
112 
113 struct svc_xprt_class svc_rdma_bc_class = {
114 	.xcl_name = "rdma-bc",
115 	.xcl_owner = THIS_MODULE,
116 	.xcl_ops = &svc_rdma_bc_ops,
117 	.xcl_max_payload = (1024 - RPCRDMA_HDRLEN_MIN)
118 };
119 
120 static struct svc_xprt *svc_rdma_bc_create(struct svc_serv *serv,
121 					   struct net *net,
122 					   struct sockaddr *sa, int salen,
123 					   int flags)
124 {
125 	struct svcxprt_rdma *cma_xprt;
126 	struct svc_xprt *xprt;
127 
128 	cma_xprt = rdma_create_xprt(serv, 0);
129 	if (!cma_xprt)
130 		return ERR_PTR(-ENOMEM);
131 	xprt = &cma_xprt->sc_xprt;
132 
133 	svc_xprt_init(net, &svc_rdma_bc_class, xprt, serv);
134 	serv->sv_bc_xprt = xprt;
135 
136 	dprintk("svcrdma: %s(%p)\n", __func__, xprt);
137 	return xprt;
138 }
139 
140 static void svc_rdma_bc_detach(struct svc_xprt *xprt)
141 {
142 	dprintk("svcrdma: %s(%p)\n", __func__, xprt);
143 }
144 
145 static void svc_rdma_bc_free(struct svc_xprt *xprt)
146 {
147 	struct svcxprt_rdma *rdma =
148 		container_of(xprt, struct svcxprt_rdma, sc_xprt);
149 
150 	dprintk("svcrdma: %s(%p)\n", __func__, xprt);
151 	if (xprt)
152 		kfree(rdma);
153 }
154 #endif	/* CONFIG_SUNRPC_BACKCHANNEL */
155 
156 static struct svc_rdma_op_ctxt *alloc_ctxt(struct svcxprt_rdma *xprt,
157 					   gfp_t flags)
158 {
159 	struct svc_rdma_op_ctxt *ctxt;
160 
161 	ctxt = kmalloc(sizeof(*ctxt), flags);
162 	if (ctxt) {
163 		ctxt->xprt = xprt;
164 		INIT_LIST_HEAD(&ctxt->free);
165 		INIT_LIST_HEAD(&ctxt->dto_q);
166 	}
167 	return ctxt;
168 }
169 
170 static bool svc_rdma_prealloc_ctxts(struct svcxprt_rdma *xprt)
171 {
172 	unsigned int i;
173 
174 	/* Each RPC/RDMA credit can consume a number of send
175 	 * and receive WQEs. One ctxt is allocated for each.
176 	 */
177 	i = xprt->sc_sq_depth + xprt->sc_rq_depth;
178 
179 	while (i--) {
180 		struct svc_rdma_op_ctxt *ctxt;
181 
182 		ctxt = alloc_ctxt(xprt, GFP_KERNEL);
183 		if (!ctxt) {
184 			dprintk("svcrdma: No memory for RDMA ctxt\n");
185 			return false;
186 		}
187 		list_add(&ctxt->free, &xprt->sc_ctxts);
188 	}
189 	return true;
190 }
191 
192 struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *xprt)
193 {
194 	struct svc_rdma_op_ctxt *ctxt = NULL;
195 
196 	spin_lock_bh(&xprt->sc_ctxt_lock);
197 	xprt->sc_ctxt_used++;
198 	if (list_empty(&xprt->sc_ctxts))
199 		goto out_empty;
200 
201 	ctxt = list_first_entry(&xprt->sc_ctxts,
202 				struct svc_rdma_op_ctxt, free);
203 	list_del_init(&ctxt->free);
204 	spin_unlock_bh(&xprt->sc_ctxt_lock);
205 
206 out:
207 	ctxt->count = 0;
208 	ctxt->frmr = NULL;
209 	return ctxt;
210 
211 out_empty:
212 	/* Either pre-allocation missed the mark, or send
213 	 * queue accounting is broken.
214 	 */
215 	spin_unlock_bh(&xprt->sc_ctxt_lock);
216 
217 	ctxt = alloc_ctxt(xprt, GFP_NOIO);
218 	if (ctxt)
219 		goto out;
220 
221 	spin_lock_bh(&xprt->sc_ctxt_lock);
222 	xprt->sc_ctxt_used--;
223 	spin_unlock_bh(&xprt->sc_ctxt_lock);
224 	WARN_ONCE(1, "svcrdma: empty RDMA ctxt list?\n");
225 	return NULL;
226 }
227 
228 void svc_rdma_unmap_dma(struct svc_rdma_op_ctxt *ctxt)
229 {
230 	struct svcxprt_rdma *xprt = ctxt->xprt;
231 	int i;
232 	for (i = 0; i < ctxt->count && ctxt->sge[i].length; 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 == xprt->sc_pd->local_dma_lkey) {
240 			atomic_dec(&xprt->sc_dma_used);
241 			ib_dma_unmap_page(xprt->sc_cm_id->device,
242 					    ctxt->sge[i].addr,
243 					    ctxt->sge[i].length,
244 					    ctxt->direction);
245 		}
246 	}
247 }
248 
249 void svc_rdma_put_context(struct svc_rdma_op_ctxt *ctxt, int free_pages)
250 {
251 	struct svcxprt_rdma *xprt = ctxt->xprt;
252 	int i;
253 
254 	if (free_pages)
255 		for (i = 0; i < ctxt->count; i++)
256 			put_page(ctxt->pages[i]);
257 
258 	spin_lock_bh(&xprt->sc_ctxt_lock);
259 	xprt->sc_ctxt_used--;
260 	list_add(&ctxt->free, &xprt->sc_ctxts);
261 	spin_unlock_bh(&xprt->sc_ctxt_lock);
262 }
263 
264 static void svc_rdma_destroy_ctxts(struct svcxprt_rdma *xprt)
265 {
266 	while (!list_empty(&xprt->sc_ctxts)) {
267 		struct svc_rdma_op_ctxt *ctxt;
268 
269 		ctxt = list_first_entry(&xprt->sc_ctxts,
270 					struct svc_rdma_op_ctxt, free);
271 		list_del(&ctxt->free);
272 		kfree(ctxt);
273 	}
274 }
275 
276 static struct svc_rdma_req_map *alloc_req_map(gfp_t flags)
277 {
278 	struct svc_rdma_req_map *map;
279 
280 	map = kmalloc(sizeof(*map), flags);
281 	if (map)
282 		INIT_LIST_HEAD(&map->free);
283 	return map;
284 }
285 
286 static bool svc_rdma_prealloc_maps(struct svcxprt_rdma *xprt)
287 {
288 	unsigned int i;
289 
290 	/* One for each receive buffer on this connection. */
291 	i = xprt->sc_max_requests;
292 
293 	while (i--) {
294 		struct svc_rdma_req_map *map;
295 
296 		map = alloc_req_map(GFP_KERNEL);
297 		if (!map) {
298 			dprintk("svcrdma: No memory for request map\n");
299 			return false;
300 		}
301 		list_add(&map->free, &xprt->sc_maps);
302 	}
303 	return true;
304 }
305 
306 struct svc_rdma_req_map *svc_rdma_get_req_map(struct svcxprt_rdma *xprt)
307 {
308 	struct svc_rdma_req_map *map = NULL;
309 
310 	spin_lock(&xprt->sc_map_lock);
311 	if (list_empty(&xprt->sc_maps))
312 		goto out_empty;
313 
314 	map = list_first_entry(&xprt->sc_maps,
315 			       struct svc_rdma_req_map, free);
316 	list_del_init(&map->free);
317 	spin_unlock(&xprt->sc_map_lock);
318 
319 out:
320 	map->count = 0;
321 	return map;
322 
323 out_empty:
324 	spin_unlock(&xprt->sc_map_lock);
325 
326 	/* Pre-allocation amount was incorrect */
327 	map = alloc_req_map(GFP_NOIO);
328 	if (map)
329 		goto out;
330 
331 	WARN_ONCE(1, "svcrdma: empty request map list?\n");
332 	return NULL;
333 }
334 
335 void svc_rdma_put_req_map(struct svcxprt_rdma *xprt,
336 			  struct svc_rdma_req_map *map)
337 {
338 	spin_lock(&xprt->sc_map_lock);
339 	list_add(&map->free, &xprt->sc_maps);
340 	spin_unlock(&xprt->sc_map_lock);
341 }
342 
343 static void svc_rdma_destroy_maps(struct svcxprt_rdma *xprt)
344 {
345 	while (!list_empty(&xprt->sc_maps)) {
346 		struct svc_rdma_req_map *map;
347 
348 		map = list_first_entry(&xprt->sc_maps,
349 				       struct svc_rdma_req_map, free);
350 		list_del(&map->free);
351 		kfree(map);
352 	}
353 }
354 
355 /* ib_cq event handler */
356 static void cq_event_handler(struct ib_event *event, void *context)
357 {
358 	struct svc_xprt *xprt = context;
359 	dprintk("svcrdma: received CQ event %s (%d), context=%p\n",
360 		ib_event_msg(event->event), event->event, context);
361 	set_bit(XPT_CLOSE, &xprt->xpt_flags);
362 }
363 
364 /* QP event handler */
365 static void qp_event_handler(struct ib_event *event, void *context)
366 {
367 	struct svc_xprt *xprt = context;
368 
369 	switch (event->event) {
370 	/* These are considered benign events */
371 	case IB_EVENT_PATH_MIG:
372 	case IB_EVENT_COMM_EST:
373 	case IB_EVENT_SQ_DRAINED:
374 	case IB_EVENT_QP_LAST_WQE_REACHED:
375 		dprintk("svcrdma: QP event %s (%d) received for QP=%p\n",
376 			ib_event_msg(event->event), event->event,
377 			event->element.qp);
378 		break;
379 	/* These are considered fatal events */
380 	case IB_EVENT_PATH_MIG_ERR:
381 	case IB_EVENT_QP_FATAL:
382 	case IB_EVENT_QP_REQ_ERR:
383 	case IB_EVENT_QP_ACCESS_ERR:
384 	case IB_EVENT_DEVICE_FATAL:
385 	default:
386 		dprintk("svcrdma: QP ERROR event %s (%d) received for QP=%p, "
387 			"closing transport\n",
388 			ib_event_msg(event->event), event->event,
389 			event->element.qp);
390 		set_bit(XPT_CLOSE, &xprt->xpt_flags);
391 		break;
392 	}
393 }
394 
395 /*
396  * Data Transfer Operation Tasklet
397  *
398  * Walks a list of transports with I/O pending, removing entries as
399  * they are added to the server's I/O pending list. Two bits indicate
400  * if SQ, RQ, or both have I/O pending. The dto_lock is an irqsave
401  * spinlock that serializes access to the transport list with the RQ
402  * and SQ interrupt handlers.
403  */
404 static void dto_tasklet_func(unsigned long data)
405 {
406 	struct svcxprt_rdma *xprt;
407 	unsigned long flags;
408 
409 	spin_lock_irqsave(&dto_lock, flags);
410 	while (!list_empty(&dto_xprt_q)) {
411 		xprt = list_entry(dto_xprt_q.next,
412 				  struct svcxprt_rdma, sc_dto_q);
413 		list_del_init(&xprt->sc_dto_q);
414 		spin_unlock_irqrestore(&dto_lock, flags);
415 
416 		rq_cq_reap(xprt);
417 		sq_cq_reap(xprt);
418 
419 		svc_xprt_put(&xprt->sc_xprt);
420 		spin_lock_irqsave(&dto_lock, flags);
421 	}
422 	spin_unlock_irqrestore(&dto_lock, flags);
423 }
424 
425 /*
426  * Receive Queue Completion Handler
427  *
428  * Since an RQ completion handler is called on interrupt context, we
429  * need to defer the handling of the I/O to a tasklet
430  */
431 static void rq_comp_handler(struct ib_cq *cq, void *cq_context)
432 {
433 	struct svcxprt_rdma *xprt = cq_context;
434 	unsigned long flags;
435 
436 	/* Guard against unconditional flush call for destroyed QP */
437 	if (atomic_read(&xprt->sc_xprt.xpt_ref.refcount)==0)
438 		return;
439 
440 	/*
441 	 * Set the bit regardless of whether or not it's on the list
442 	 * because it may be on the list already due to an SQ
443 	 * completion.
444 	 */
445 	set_bit(RDMAXPRT_RQ_PENDING, &xprt->sc_flags);
446 
447 	/*
448 	 * If this transport is not already on the DTO transport queue,
449 	 * add it
450 	 */
451 	spin_lock_irqsave(&dto_lock, flags);
452 	if (list_empty(&xprt->sc_dto_q)) {
453 		svc_xprt_get(&xprt->sc_xprt);
454 		list_add_tail(&xprt->sc_dto_q, &dto_xprt_q);
455 	}
456 	spin_unlock_irqrestore(&dto_lock, flags);
457 
458 	/* Tasklet does all the work to avoid irqsave locks. */
459 	tasklet_schedule(&dto_tasklet);
460 }
461 
462 /*
463  * rq_cq_reap - Process the RQ CQ.
464  *
465  * Take all completing WC off the CQE and enqueue the associated DTO
466  * context on the dto_q for the transport.
467  *
468  * Note that caller must hold a transport reference.
469  */
470 static void rq_cq_reap(struct svcxprt_rdma *xprt)
471 {
472 	int ret;
473 	struct ib_wc wc;
474 	struct svc_rdma_op_ctxt *ctxt = NULL;
475 
476 	if (!test_and_clear_bit(RDMAXPRT_RQ_PENDING, &xprt->sc_flags))
477 		return;
478 
479 	ib_req_notify_cq(xprt->sc_rq_cq, IB_CQ_NEXT_COMP);
480 	atomic_inc(&rdma_stat_rq_poll);
481 
482 	while ((ret = ib_poll_cq(xprt->sc_rq_cq, 1, &wc)) > 0) {
483 		ctxt = (struct svc_rdma_op_ctxt *)(unsigned long)wc.wr_id;
484 		ctxt->wc_status = wc.status;
485 		ctxt->byte_len = wc.byte_len;
486 		svc_rdma_unmap_dma(ctxt);
487 		if (wc.status != IB_WC_SUCCESS) {
488 			/* Close the transport */
489 			dprintk("svcrdma: transport closing putting ctxt %p\n", ctxt);
490 			set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
491 			svc_rdma_put_context(ctxt, 1);
492 			svc_xprt_put(&xprt->sc_xprt);
493 			continue;
494 		}
495 		spin_lock_bh(&xprt->sc_rq_dto_lock);
496 		list_add_tail(&ctxt->dto_q, &xprt->sc_rq_dto_q);
497 		spin_unlock_bh(&xprt->sc_rq_dto_lock);
498 		svc_xprt_put(&xprt->sc_xprt);
499 	}
500 
501 	if (ctxt)
502 		atomic_inc(&rdma_stat_rq_prod);
503 
504 	set_bit(XPT_DATA, &xprt->sc_xprt.xpt_flags);
505 	/*
506 	 * If data arrived before established event,
507 	 * don't enqueue. This defers RPC I/O until the
508 	 * RDMA connection is complete.
509 	 */
510 	if (!test_bit(RDMAXPRT_CONN_PENDING, &xprt->sc_flags))
511 		svc_xprt_enqueue(&xprt->sc_xprt);
512 }
513 
514 /*
515  * Process a completion context
516  */
517 static void process_context(struct svcxprt_rdma *xprt,
518 			    struct svc_rdma_op_ctxt *ctxt)
519 {
520 	struct svc_rdma_op_ctxt *read_hdr;
521 	int free_pages = 0;
522 
523 	svc_rdma_unmap_dma(ctxt);
524 
525 	switch (ctxt->wr_op) {
526 	case IB_WR_SEND:
527 		free_pages = 1;
528 		break;
529 
530 	case IB_WR_RDMA_WRITE:
531 		break;
532 
533 	case IB_WR_RDMA_READ:
534 	case IB_WR_RDMA_READ_WITH_INV:
535 		svc_rdma_put_frmr(xprt, ctxt->frmr);
536 
537 		if (!test_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags))
538 			break;
539 
540 		read_hdr = ctxt->read_hdr;
541 		svc_rdma_put_context(ctxt, 0);
542 
543 		spin_lock_bh(&xprt->sc_rq_dto_lock);
544 		set_bit(XPT_DATA, &xprt->sc_xprt.xpt_flags);
545 		list_add_tail(&read_hdr->dto_q,
546 			      &xprt->sc_read_complete_q);
547 		spin_unlock_bh(&xprt->sc_rq_dto_lock);
548 		svc_xprt_enqueue(&xprt->sc_xprt);
549 		return;
550 
551 	default:
552 		dprintk("svcrdma: unexpected completion opcode=%d\n",
553 			ctxt->wr_op);
554 		break;
555 	}
556 
557 	svc_rdma_put_context(ctxt, free_pages);
558 }
559 
560 /*
561  * Send Queue Completion Handler - potentially called on interrupt context.
562  *
563  * Note that caller must hold a transport reference.
564  */
565 static void sq_cq_reap(struct svcxprt_rdma *xprt)
566 {
567 	struct svc_rdma_op_ctxt *ctxt = NULL;
568 	struct ib_wc wc_a[6];
569 	struct ib_wc *wc;
570 	struct ib_cq *cq = xprt->sc_sq_cq;
571 	int ret;
572 
573 	memset(wc_a, 0, sizeof(wc_a));
574 
575 	if (!test_and_clear_bit(RDMAXPRT_SQ_PENDING, &xprt->sc_flags))
576 		return;
577 
578 	ib_req_notify_cq(xprt->sc_sq_cq, IB_CQ_NEXT_COMP);
579 	atomic_inc(&rdma_stat_sq_poll);
580 	while ((ret = ib_poll_cq(cq, ARRAY_SIZE(wc_a), wc_a)) > 0) {
581 		int i;
582 
583 		for (i = 0; i < ret; i++) {
584 			wc = &wc_a[i];
585 			if (wc->status != IB_WC_SUCCESS) {
586 				dprintk("svcrdma: sq wc err status %s (%d)\n",
587 					ib_wc_status_msg(wc->status),
588 					wc->status);
589 
590 				/* Close the transport */
591 				set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
592 			}
593 
594 			/* Decrement used SQ WR count */
595 			atomic_dec(&xprt->sc_sq_count);
596 			wake_up(&xprt->sc_send_wait);
597 
598 			ctxt = (struct svc_rdma_op_ctxt *)
599 				(unsigned long)wc->wr_id;
600 			if (ctxt)
601 				process_context(xprt, ctxt);
602 
603 			svc_xprt_put(&xprt->sc_xprt);
604 		}
605 	}
606 
607 	if (ctxt)
608 		atomic_inc(&rdma_stat_sq_prod);
609 }
610 
611 static void sq_comp_handler(struct ib_cq *cq, void *cq_context)
612 {
613 	struct svcxprt_rdma *xprt = cq_context;
614 	unsigned long flags;
615 
616 	/* Guard against unconditional flush call for destroyed QP */
617 	if (atomic_read(&xprt->sc_xprt.xpt_ref.refcount)==0)
618 		return;
619 
620 	/*
621 	 * Set the bit regardless of whether or not it's on the list
622 	 * because it may be on the list already due to an RQ
623 	 * completion.
624 	 */
625 	set_bit(RDMAXPRT_SQ_PENDING, &xprt->sc_flags);
626 
627 	/*
628 	 * If this transport is not already on the DTO transport queue,
629 	 * add it
630 	 */
631 	spin_lock_irqsave(&dto_lock, flags);
632 	if (list_empty(&xprt->sc_dto_q)) {
633 		svc_xprt_get(&xprt->sc_xprt);
634 		list_add_tail(&xprt->sc_dto_q, &dto_xprt_q);
635 	}
636 	spin_unlock_irqrestore(&dto_lock, flags);
637 
638 	/* Tasklet does all the work to avoid irqsave locks. */
639 	tasklet_schedule(&dto_tasklet);
640 }
641 
642 static struct svcxprt_rdma *rdma_create_xprt(struct svc_serv *serv,
643 					     int listener)
644 {
645 	struct svcxprt_rdma *cma_xprt = kzalloc(sizeof *cma_xprt, GFP_KERNEL);
646 
647 	if (!cma_xprt)
648 		return NULL;
649 	svc_xprt_init(&init_net, &svc_rdma_class, &cma_xprt->sc_xprt, serv);
650 	INIT_LIST_HEAD(&cma_xprt->sc_accept_q);
651 	INIT_LIST_HEAD(&cma_xprt->sc_dto_q);
652 	INIT_LIST_HEAD(&cma_xprt->sc_rq_dto_q);
653 	INIT_LIST_HEAD(&cma_xprt->sc_read_complete_q);
654 	INIT_LIST_HEAD(&cma_xprt->sc_frmr_q);
655 	INIT_LIST_HEAD(&cma_xprt->sc_ctxts);
656 	INIT_LIST_HEAD(&cma_xprt->sc_maps);
657 	init_waitqueue_head(&cma_xprt->sc_send_wait);
658 
659 	spin_lock_init(&cma_xprt->sc_lock);
660 	spin_lock_init(&cma_xprt->sc_rq_dto_lock);
661 	spin_lock_init(&cma_xprt->sc_frmr_q_lock);
662 	spin_lock_init(&cma_xprt->sc_ctxt_lock);
663 	spin_lock_init(&cma_xprt->sc_map_lock);
664 
665 	if (listener)
666 		set_bit(XPT_LISTENER, &cma_xprt->sc_xprt.xpt_flags);
667 
668 	return cma_xprt;
669 }
670 
671 int svc_rdma_post_recv(struct svcxprt_rdma *xprt, gfp_t flags)
672 {
673 	struct ib_recv_wr recv_wr, *bad_recv_wr;
674 	struct svc_rdma_op_ctxt *ctxt;
675 	struct page *page;
676 	dma_addr_t pa;
677 	int sge_no;
678 	int buflen;
679 	int ret;
680 
681 	ctxt = svc_rdma_get_context(xprt);
682 	buflen = 0;
683 	ctxt->direction = DMA_FROM_DEVICE;
684 	for (sge_no = 0; buflen < xprt->sc_max_req_size; sge_no++) {
685 		if (sge_no >= xprt->sc_max_sge) {
686 			pr_err("svcrdma: Too many sges (%d)\n", sge_no);
687 			goto err_put_ctxt;
688 		}
689 		page = alloc_page(flags);
690 		if (!page)
691 			goto err_put_ctxt;
692 		ctxt->pages[sge_no] = page;
693 		pa = ib_dma_map_page(xprt->sc_cm_id->device,
694 				     page, 0, PAGE_SIZE,
695 				     DMA_FROM_DEVICE);
696 		if (ib_dma_mapping_error(xprt->sc_cm_id->device, pa))
697 			goto err_put_ctxt;
698 		atomic_inc(&xprt->sc_dma_used);
699 		ctxt->sge[sge_no].addr = pa;
700 		ctxt->sge[sge_no].length = PAGE_SIZE;
701 		ctxt->sge[sge_no].lkey = xprt->sc_pd->local_dma_lkey;
702 		ctxt->count = sge_no + 1;
703 		buflen += PAGE_SIZE;
704 	}
705 	recv_wr.next = NULL;
706 	recv_wr.sg_list = &ctxt->sge[0];
707 	recv_wr.num_sge = ctxt->count;
708 	recv_wr.wr_id = (u64)(unsigned long)ctxt;
709 
710 	svc_xprt_get(&xprt->sc_xprt);
711 	ret = ib_post_recv(xprt->sc_qp, &recv_wr, &bad_recv_wr);
712 	if (ret) {
713 		svc_rdma_unmap_dma(ctxt);
714 		svc_rdma_put_context(ctxt, 1);
715 		svc_xprt_put(&xprt->sc_xprt);
716 	}
717 	return ret;
718 
719  err_put_ctxt:
720 	svc_rdma_unmap_dma(ctxt);
721 	svc_rdma_put_context(ctxt, 1);
722 	return -ENOMEM;
723 }
724 
725 /*
726  * This function handles the CONNECT_REQUEST event on a listening
727  * endpoint. It is passed the cma_id for the _new_ connection. The context in
728  * this cma_id is inherited from the listening cma_id and is the svc_xprt
729  * structure for the listening endpoint.
730  *
731  * This function creates a new xprt for the new connection and enqueues it on
732  * the accept queue for the listent xprt. When the listen thread is kicked, it
733  * will call the recvfrom method on the listen xprt which will accept the new
734  * connection.
735  */
736 static void handle_connect_req(struct rdma_cm_id *new_cma_id, size_t client_ird)
737 {
738 	struct svcxprt_rdma *listen_xprt = new_cma_id->context;
739 	struct svcxprt_rdma *newxprt;
740 	struct sockaddr *sa;
741 
742 	/* Create a new transport */
743 	newxprt = rdma_create_xprt(listen_xprt->sc_xprt.xpt_server, 0);
744 	if (!newxprt) {
745 		dprintk("svcrdma: failed to create new transport\n");
746 		return;
747 	}
748 	newxprt->sc_cm_id = new_cma_id;
749 	new_cma_id->context = newxprt;
750 	dprintk("svcrdma: Creating newxprt=%p, cm_id=%p, listenxprt=%p\n",
751 		newxprt, newxprt->sc_cm_id, listen_xprt);
752 
753 	/* Save client advertised inbound read limit for use later in accept. */
754 	newxprt->sc_ord = client_ird;
755 
756 	/* Set the local and remote addresses in the transport */
757 	sa = (struct sockaddr *)&newxprt->sc_cm_id->route.addr.dst_addr;
758 	svc_xprt_set_remote(&newxprt->sc_xprt, sa, svc_addr_len(sa));
759 	sa = (struct sockaddr *)&newxprt->sc_cm_id->route.addr.src_addr;
760 	svc_xprt_set_local(&newxprt->sc_xprt, sa, svc_addr_len(sa));
761 
762 	/*
763 	 * Enqueue the new transport on the accept queue of the listening
764 	 * transport
765 	 */
766 	spin_lock_bh(&listen_xprt->sc_lock);
767 	list_add_tail(&newxprt->sc_accept_q, &listen_xprt->sc_accept_q);
768 	spin_unlock_bh(&listen_xprt->sc_lock);
769 
770 	set_bit(XPT_CONN, &listen_xprt->sc_xprt.xpt_flags);
771 	svc_xprt_enqueue(&listen_xprt->sc_xprt);
772 }
773 
774 /*
775  * Handles events generated on the listening endpoint. These events will be
776  * either be incoming connect requests or adapter removal  events.
777  */
778 static int rdma_listen_handler(struct rdma_cm_id *cma_id,
779 			       struct rdma_cm_event *event)
780 {
781 	struct svcxprt_rdma *xprt = cma_id->context;
782 	int ret = 0;
783 
784 	switch (event->event) {
785 	case RDMA_CM_EVENT_CONNECT_REQUEST:
786 		dprintk("svcrdma: Connect request on cma_id=%p, xprt = %p, "
787 			"event = %s (%d)\n", cma_id, cma_id->context,
788 			rdma_event_msg(event->event), event->event);
789 		handle_connect_req(cma_id,
790 				   event->param.conn.initiator_depth);
791 		break;
792 
793 	case RDMA_CM_EVENT_ESTABLISHED:
794 		/* Accept complete */
795 		dprintk("svcrdma: Connection completed on LISTEN xprt=%p, "
796 			"cm_id=%p\n", xprt, cma_id);
797 		break;
798 
799 	case RDMA_CM_EVENT_DEVICE_REMOVAL:
800 		dprintk("svcrdma: Device removal xprt=%p, cm_id=%p\n",
801 			xprt, cma_id);
802 		if (xprt)
803 			set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
804 		break;
805 
806 	default:
807 		dprintk("svcrdma: Unexpected event on listening endpoint %p, "
808 			"event = %s (%d)\n", cma_id,
809 			rdma_event_msg(event->event), event->event);
810 		break;
811 	}
812 
813 	return ret;
814 }
815 
816 static int rdma_cma_handler(struct rdma_cm_id *cma_id,
817 			    struct rdma_cm_event *event)
818 {
819 	struct svc_xprt *xprt = cma_id->context;
820 	struct svcxprt_rdma *rdma =
821 		container_of(xprt, struct svcxprt_rdma, sc_xprt);
822 	switch (event->event) {
823 	case RDMA_CM_EVENT_ESTABLISHED:
824 		/* Accept complete */
825 		svc_xprt_get(xprt);
826 		dprintk("svcrdma: Connection completed on DTO xprt=%p, "
827 			"cm_id=%p\n", xprt, cma_id);
828 		clear_bit(RDMAXPRT_CONN_PENDING, &rdma->sc_flags);
829 		svc_xprt_enqueue(xprt);
830 		break;
831 	case RDMA_CM_EVENT_DISCONNECTED:
832 		dprintk("svcrdma: Disconnect on DTO xprt=%p, cm_id=%p\n",
833 			xprt, cma_id);
834 		if (xprt) {
835 			set_bit(XPT_CLOSE, &xprt->xpt_flags);
836 			svc_xprt_enqueue(xprt);
837 			svc_xprt_put(xprt);
838 		}
839 		break;
840 	case RDMA_CM_EVENT_DEVICE_REMOVAL:
841 		dprintk("svcrdma: Device removal cma_id=%p, xprt = %p, "
842 			"event = %s (%d)\n", cma_id, xprt,
843 			rdma_event_msg(event->event), event->event);
844 		if (xprt) {
845 			set_bit(XPT_CLOSE, &xprt->xpt_flags);
846 			svc_xprt_enqueue(xprt);
847 			svc_xprt_put(xprt);
848 		}
849 		break;
850 	default:
851 		dprintk("svcrdma: Unexpected event on DTO endpoint %p, "
852 			"event = %s (%d)\n", cma_id,
853 			rdma_event_msg(event->event), event->event);
854 		break;
855 	}
856 	return 0;
857 }
858 
859 /*
860  * Create a listening RDMA service endpoint.
861  */
862 static struct svc_xprt *svc_rdma_create(struct svc_serv *serv,
863 					struct net *net,
864 					struct sockaddr *sa, int salen,
865 					int flags)
866 {
867 	struct rdma_cm_id *listen_id;
868 	struct svcxprt_rdma *cma_xprt;
869 	int ret;
870 
871 	dprintk("svcrdma: Creating RDMA socket\n");
872 	if (sa->sa_family != AF_INET) {
873 		dprintk("svcrdma: Address family %d is not supported.\n", sa->sa_family);
874 		return ERR_PTR(-EAFNOSUPPORT);
875 	}
876 	cma_xprt = rdma_create_xprt(serv, 1);
877 	if (!cma_xprt)
878 		return ERR_PTR(-ENOMEM);
879 
880 	listen_id = rdma_create_id(&init_net, rdma_listen_handler, cma_xprt,
881 				   RDMA_PS_TCP, IB_QPT_RC);
882 	if (IS_ERR(listen_id)) {
883 		ret = PTR_ERR(listen_id);
884 		dprintk("svcrdma: rdma_create_id failed = %d\n", ret);
885 		goto err0;
886 	}
887 
888 	ret = rdma_bind_addr(listen_id, sa);
889 	if (ret) {
890 		dprintk("svcrdma: rdma_bind_addr failed = %d\n", ret);
891 		goto err1;
892 	}
893 	cma_xprt->sc_cm_id = listen_id;
894 
895 	ret = rdma_listen(listen_id, RPCRDMA_LISTEN_BACKLOG);
896 	if (ret) {
897 		dprintk("svcrdma: rdma_listen failed = %d\n", ret);
898 		goto err1;
899 	}
900 
901 	/*
902 	 * We need to use the address from the cm_id in case the
903 	 * caller specified 0 for the port number.
904 	 */
905 	sa = (struct sockaddr *)&cma_xprt->sc_cm_id->route.addr.src_addr;
906 	svc_xprt_set_local(&cma_xprt->sc_xprt, sa, salen);
907 
908 	return &cma_xprt->sc_xprt;
909 
910  err1:
911 	rdma_destroy_id(listen_id);
912  err0:
913 	kfree(cma_xprt);
914 	return ERR_PTR(ret);
915 }
916 
917 static struct svc_rdma_fastreg_mr *rdma_alloc_frmr(struct svcxprt_rdma *xprt)
918 {
919 	struct ib_mr *mr;
920 	struct scatterlist *sg;
921 	struct svc_rdma_fastreg_mr *frmr;
922 	u32 num_sg;
923 
924 	frmr = kmalloc(sizeof(*frmr), GFP_KERNEL);
925 	if (!frmr)
926 		goto err;
927 
928 	num_sg = min_t(u32, RPCSVC_MAXPAGES, xprt->sc_frmr_pg_list_len);
929 	mr = ib_alloc_mr(xprt->sc_pd, IB_MR_TYPE_MEM_REG, num_sg);
930 	if (IS_ERR(mr))
931 		goto err_free_frmr;
932 
933 	sg = kcalloc(RPCSVC_MAXPAGES, sizeof(*sg), GFP_KERNEL);
934 	if (!sg)
935 		goto err_free_mr;
936 
937 	sg_init_table(sg, RPCSVC_MAXPAGES);
938 
939 	frmr->mr = mr;
940 	frmr->sg = sg;
941 	INIT_LIST_HEAD(&frmr->frmr_list);
942 	return frmr;
943 
944  err_free_mr:
945 	ib_dereg_mr(mr);
946  err_free_frmr:
947 	kfree(frmr);
948  err:
949 	return ERR_PTR(-ENOMEM);
950 }
951 
952 static void rdma_dealloc_frmr_q(struct svcxprt_rdma *xprt)
953 {
954 	struct svc_rdma_fastreg_mr *frmr;
955 
956 	while (!list_empty(&xprt->sc_frmr_q)) {
957 		frmr = list_entry(xprt->sc_frmr_q.next,
958 				  struct svc_rdma_fastreg_mr, frmr_list);
959 		list_del_init(&frmr->frmr_list);
960 		kfree(frmr->sg);
961 		ib_dereg_mr(frmr->mr);
962 		kfree(frmr);
963 	}
964 }
965 
966 struct svc_rdma_fastreg_mr *svc_rdma_get_frmr(struct svcxprt_rdma *rdma)
967 {
968 	struct svc_rdma_fastreg_mr *frmr = NULL;
969 
970 	spin_lock_bh(&rdma->sc_frmr_q_lock);
971 	if (!list_empty(&rdma->sc_frmr_q)) {
972 		frmr = list_entry(rdma->sc_frmr_q.next,
973 				  struct svc_rdma_fastreg_mr, frmr_list);
974 		list_del_init(&frmr->frmr_list);
975 		frmr->sg_nents = 0;
976 	}
977 	spin_unlock_bh(&rdma->sc_frmr_q_lock);
978 	if (frmr)
979 		return frmr;
980 
981 	return rdma_alloc_frmr(rdma);
982 }
983 
984 void svc_rdma_put_frmr(struct svcxprt_rdma *rdma,
985 		       struct svc_rdma_fastreg_mr *frmr)
986 {
987 	if (frmr) {
988 		ib_dma_unmap_sg(rdma->sc_cm_id->device,
989 				frmr->sg, frmr->sg_nents, frmr->direction);
990 		atomic_dec(&rdma->sc_dma_used);
991 		spin_lock_bh(&rdma->sc_frmr_q_lock);
992 		WARN_ON_ONCE(!list_empty(&frmr->frmr_list));
993 		list_add(&frmr->frmr_list, &rdma->sc_frmr_q);
994 		spin_unlock_bh(&rdma->sc_frmr_q_lock);
995 	}
996 }
997 
998 /*
999  * This is the xpo_recvfrom function for listening endpoints. Its
1000  * purpose is to accept incoming connections. The CMA callback handler
1001  * has already created a new transport and attached it to the new CMA
1002  * ID.
1003  *
1004  * There is a queue of pending connections hung on the listening
1005  * transport. This queue contains the new svc_xprt structure. This
1006  * function takes svc_xprt structures off the accept_q and completes
1007  * the connection.
1008  */
1009 static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
1010 {
1011 	struct svcxprt_rdma *listen_rdma;
1012 	struct svcxprt_rdma *newxprt = NULL;
1013 	struct rdma_conn_param conn_param;
1014 	struct ib_cq_init_attr cq_attr = {};
1015 	struct ib_qp_init_attr qp_attr;
1016 	struct ib_device *dev;
1017 	unsigned int i;
1018 	int ret = 0;
1019 
1020 	listen_rdma = container_of(xprt, struct svcxprt_rdma, sc_xprt);
1021 	clear_bit(XPT_CONN, &xprt->xpt_flags);
1022 	/* Get the next entry off the accept list */
1023 	spin_lock_bh(&listen_rdma->sc_lock);
1024 	if (!list_empty(&listen_rdma->sc_accept_q)) {
1025 		newxprt = list_entry(listen_rdma->sc_accept_q.next,
1026 				     struct svcxprt_rdma, sc_accept_q);
1027 		list_del_init(&newxprt->sc_accept_q);
1028 	}
1029 	if (!list_empty(&listen_rdma->sc_accept_q))
1030 		set_bit(XPT_CONN, &listen_rdma->sc_xprt.xpt_flags);
1031 	spin_unlock_bh(&listen_rdma->sc_lock);
1032 	if (!newxprt)
1033 		return NULL;
1034 
1035 	dprintk("svcrdma: newxprt from accept queue = %p, cm_id=%p\n",
1036 		newxprt, newxprt->sc_cm_id);
1037 
1038 	dev = newxprt->sc_cm_id->device;
1039 
1040 	/* Qualify the transport resource defaults with the
1041 	 * capabilities of this particular device */
1042 	newxprt->sc_max_sge = min((size_t)dev->attrs.max_sge,
1043 				  (size_t)RPCSVC_MAXPAGES);
1044 	newxprt->sc_max_sge_rd = min_t(size_t, dev->attrs.max_sge_rd,
1045 				       RPCSVC_MAXPAGES);
1046 	newxprt->sc_max_req_size = svcrdma_max_req_size;
1047 	newxprt->sc_max_requests = min_t(u32, dev->attrs.max_qp_wr,
1048 					 svcrdma_max_requests);
1049 	newxprt->sc_max_bc_requests = min_t(u32, dev->attrs.max_qp_wr,
1050 					    svcrdma_max_bc_requests);
1051 	newxprt->sc_rq_depth = newxprt->sc_max_requests +
1052 			       newxprt->sc_max_bc_requests;
1053 	newxprt->sc_sq_depth = RPCRDMA_SQ_DEPTH_MULT * newxprt->sc_rq_depth;
1054 
1055 	if (!svc_rdma_prealloc_ctxts(newxprt))
1056 		goto errout;
1057 	if (!svc_rdma_prealloc_maps(newxprt))
1058 		goto errout;
1059 
1060 	/*
1061 	 * Limit ORD based on client limit, local device limit, and
1062 	 * configured svcrdma limit.
1063 	 */
1064 	newxprt->sc_ord = min_t(size_t, dev->attrs.max_qp_rd_atom, newxprt->sc_ord);
1065 	newxprt->sc_ord = min_t(size_t,	svcrdma_ord, newxprt->sc_ord);
1066 
1067 	newxprt->sc_pd = ib_alloc_pd(dev);
1068 	if (IS_ERR(newxprt->sc_pd)) {
1069 		dprintk("svcrdma: error creating PD for connect request\n");
1070 		goto errout;
1071 	}
1072 	cq_attr.cqe = newxprt->sc_sq_depth;
1073 	newxprt->sc_sq_cq = ib_create_cq(dev,
1074 					 sq_comp_handler,
1075 					 cq_event_handler,
1076 					 newxprt,
1077 					 &cq_attr);
1078 	if (IS_ERR(newxprt->sc_sq_cq)) {
1079 		dprintk("svcrdma: error creating SQ CQ for connect request\n");
1080 		goto errout;
1081 	}
1082 	cq_attr.cqe = newxprt->sc_rq_depth;
1083 	newxprt->sc_rq_cq = ib_create_cq(dev,
1084 					 rq_comp_handler,
1085 					 cq_event_handler,
1086 					 newxprt,
1087 					 &cq_attr);
1088 	if (IS_ERR(newxprt->sc_rq_cq)) {
1089 		dprintk("svcrdma: error creating RQ CQ for connect request\n");
1090 		goto errout;
1091 	}
1092 
1093 	memset(&qp_attr, 0, sizeof qp_attr);
1094 	qp_attr.event_handler = qp_event_handler;
1095 	qp_attr.qp_context = &newxprt->sc_xprt;
1096 	qp_attr.cap.max_send_wr = newxprt->sc_sq_depth;
1097 	qp_attr.cap.max_recv_wr = newxprt->sc_rq_depth;
1098 	qp_attr.cap.max_send_sge = newxprt->sc_max_sge;
1099 	qp_attr.cap.max_recv_sge = newxprt->sc_max_sge;
1100 	qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
1101 	qp_attr.qp_type = IB_QPT_RC;
1102 	qp_attr.send_cq = newxprt->sc_sq_cq;
1103 	qp_attr.recv_cq = newxprt->sc_rq_cq;
1104 	dprintk("svcrdma: newxprt->sc_cm_id=%p, newxprt->sc_pd=%p\n"
1105 		"    cm_id->device=%p, sc_pd->device=%p\n"
1106 		"    cap.max_send_wr = %d\n"
1107 		"    cap.max_recv_wr = %d\n"
1108 		"    cap.max_send_sge = %d\n"
1109 		"    cap.max_recv_sge = %d\n",
1110 		newxprt->sc_cm_id, newxprt->sc_pd,
1111 		dev, newxprt->sc_pd->device,
1112 		qp_attr.cap.max_send_wr,
1113 		qp_attr.cap.max_recv_wr,
1114 		qp_attr.cap.max_send_sge,
1115 		qp_attr.cap.max_recv_sge);
1116 
1117 	ret = rdma_create_qp(newxprt->sc_cm_id, newxprt->sc_pd, &qp_attr);
1118 	if (ret) {
1119 		dprintk("svcrdma: failed to create QP, ret=%d\n", ret);
1120 		goto errout;
1121 	}
1122 	newxprt->sc_qp = newxprt->sc_cm_id->qp;
1123 
1124 	/*
1125 	 * Use the most secure set of MR resources based on the
1126 	 * transport type and available memory management features in
1127 	 * the device. Here's the table implemented below:
1128 	 *
1129 	 *		Fast	Global	DMA	Remote WR
1130 	 *		Reg	LKEY	MR	Access
1131 	 *		Sup'd	Sup'd	Needed	Needed
1132 	 *
1133 	 * IWARP	N	N	Y	Y
1134 	 *		N	Y	Y	Y
1135 	 *		Y	N	Y	N
1136 	 *		Y	Y	N	-
1137 	 *
1138 	 * IB		N	N	Y	N
1139 	 *		N	Y	N	-
1140 	 *		Y	N	Y	N
1141 	 *		Y	Y	N	-
1142 	 *
1143 	 * NB:	iWARP requires remote write access for the data sink
1144 	 *	of an RDMA_READ. IB does not.
1145 	 */
1146 	newxprt->sc_reader = rdma_read_chunk_lcl;
1147 	if (dev->attrs.device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS) {
1148 		newxprt->sc_frmr_pg_list_len =
1149 			dev->attrs.max_fast_reg_page_list_len;
1150 		newxprt->sc_dev_caps |= SVCRDMA_DEVCAP_FAST_REG;
1151 		newxprt->sc_reader = rdma_read_chunk_frmr;
1152 	}
1153 
1154 	/*
1155 	 * Determine if a DMA MR is required and if so, what privs are required
1156 	 */
1157 	if (!rdma_protocol_iwarp(dev, newxprt->sc_cm_id->port_num) &&
1158 	    !rdma_ib_or_roce(dev, newxprt->sc_cm_id->port_num))
1159 		goto errout;
1160 
1161 	if (rdma_protocol_iwarp(dev, newxprt->sc_cm_id->port_num))
1162 		newxprt->sc_dev_caps |= SVCRDMA_DEVCAP_READ_W_INV;
1163 
1164 	/* Post receive buffers */
1165 	for (i = 0; i < newxprt->sc_rq_depth; i++) {
1166 		ret = svc_rdma_post_recv(newxprt, GFP_KERNEL);
1167 		if (ret) {
1168 			dprintk("svcrdma: failure posting receive buffers\n");
1169 			goto errout;
1170 		}
1171 	}
1172 
1173 	/* Swap out the handler */
1174 	newxprt->sc_cm_id->event_handler = rdma_cma_handler;
1175 
1176 	/*
1177 	 * Arm the CQs for the SQ and RQ before accepting so we can't
1178 	 * miss the first message
1179 	 */
1180 	ib_req_notify_cq(newxprt->sc_sq_cq, IB_CQ_NEXT_COMP);
1181 	ib_req_notify_cq(newxprt->sc_rq_cq, IB_CQ_NEXT_COMP);
1182 
1183 	/* Accept Connection */
1184 	set_bit(RDMAXPRT_CONN_PENDING, &newxprt->sc_flags);
1185 	memset(&conn_param, 0, sizeof conn_param);
1186 	conn_param.responder_resources = 0;
1187 	conn_param.initiator_depth = newxprt->sc_ord;
1188 	ret = rdma_accept(newxprt->sc_cm_id, &conn_param);
1189 	if (ret) {
1190 		dprintk("svcrdma: failed to accept new connection, ret=%d\n",
1191 		       ret);
1192 		goto errout;
1193 	}
1194 
1195 	dprintk("svcrdma: new connection %p accepted with the following "
1196 		"attributes:\n"
1197 		"    local_ip        : %pI4\n"
1198 		"    local_port	     : %d\n"
1199 		"    remote_ip       : %pI4\n"
1200 		"    remote_port     : %d\n"
1201 		"    max_sge         : %d\n"
1202 		"    max_sge_rd      : %d\n"
1203 		"    sq_depth        : %d\n"
1204 		"    max_requests    : %d\n"
1205 		"    ord             : %d\n",
1206 		newxprt,
1207 		&((struct sockaddr_in *)&newxprt->sc_cm_id->
1208 			 route.addr.src_addr)->sin_addr.s_addr,
1209 		ntohs(((struct sockaddr_in *)&newxprt->sc_cm_id->
1210 		       route.addr.src_addr)->sin_port),
1211 		&((struct sockaddr_in *)&newxprt->sc_cm_id->
1212 			 route.addr.dst_addr)->sin_addr.s_addr,
1213 		ntohs(((struct sockaddr_in *)&newxprt->sc_cm_id->
1214 		       route.addr.dst_addr)->sin_port),
1215 		newxprt->sc_max_sge,
1216 		newxprt->sc_max_sge_rd,
1217 		newxprt->sc_sq_depth,
1218 		newxprt->sc_max_requests,
1219 		newxprt->sc_ord);
1220 
1221 	return &newxprt->sc_xprt;
1222 
1223  errout:
1224 	dprintk("svcrdma: failure accepting new connection rc=%d.\n", ret);
1225 	/* Take a reference in case the DTO handler runs */
1226 	svc_xprt_get(&newxprt->sc_xprt);
1227 	if (newxprt->sc_qp && !IS_ERR(newxprt->sc_qp))
1228 		ib_destroy_qp(newxprt->sc_qp);
1229 	rdma_destroy_id(newxprt->sc_cm_id);
1230 	/* This call to put will destroy the transport */
1231 	svc_xprt_put(&newxprt->sc_xprt);
1232 	return NULL;
1233 }
1234 
1235 static void svc_rdma_release_rqst(struct svc_rqst *rqstp)
1236 {
1237 }
1238 
1239 /*
1240  * When connected, an svc_xprt has at least two references:
1241  *
1242  * - A reference held by the cm_id between the ESTABLISHED and
1243  *   DISCONNECTED events. If the remote peer disconnected first, this
1244  *   reference could be gone.
1245  *
1246  * - A reference held by the svc_recv code that called this function
1247  *   as part of close processing.
1248  *
1249  * At a minimum one references should still be held.
1250  */
1251 static void svc_rdma_detach(struct svc_xprt *xprt)
1252 {
1253 	struct svcxprt_rdma *rdma =
1254 		container_of(xprt, struct svcxprt_rdma, sc_xprt);
1255 	dprintk("svc: svc_rdma_detach(%p)\n", xprt);
1256 
1257 	/* Disconnect and flush posted WQE */
1258 	rdma_disconnect(rdma->sc_cm_id);
1259 }
1260 
1261 static void __svc_rdma_free(struct work_struct *work)
1262 {
1263 	struct svcxprt_rdma *rdma =
1264 		container_of(work, struct svcxprt_rdma, sc_work);
1265 	struct svc_xprt *xprt = &rdma->sc_xprt;
1266 
1267 	dprintk("svcrdma: %s(%p)\n", __func__, rdma);
1268 
1269 	/* We should only be called from kref_put */
1270 	if (atomic_read(&xprt->xpt_ref.refcount) != 0)
1271 		pr_err("svcrdma: sc_xprt still in use? (%d)\n",
1272 		       atomic_read(&xprt->xpt_ref.refcount));
1273 
1274 	/*
1275 	 * Destroy queued, but not processed read completions. Note
1276 	 * that this cleanup has to be done before destroying the
1277 	 * cm_id because the device ptr is needed to unmap the dma in
1278 	 * svc_rdma_put_context.
1279 	 */
1280 	while (!list_empty(&rdma->sc_read_complete_q)) {
1281 		struct svc_rdma_op_ctxt *ctxt;
1282 		ctxt = list_entry(rdma->sc_read_complete_q.next,
1283 				  struct svc_rdma_op_ctxt,
1284 				  dto_q);
1285 		list_del_init(&ctxt->dto_q);
1286 		svc_rdma_put_context(ctxt, 1);
1287 	}
1288 
1289 	/* Destroy queued, but not processed recv completions */
1290 	while (!list_empty(&rdma->sc_rq_dto_q)) {
1291 		struct svc_rdma_op_ctxt *ctxt;
1292 		ctxt = list_entry(rdma->sc_rq_dto_q.next,
1293 				  struct svc_rdma_op_ctxt,
1294 				  dto_q);
1295 		list_del_init(&ctxt->dto_q);
1296 		svc_rdma_put_context(ctxt, 1);
1297 	}
1298 
1299 	/* Warn if we leaked a resource or under-referenced */
1300 	if (rdma->sc_ctxt_used != 0)
1301 		pr_err("svcrdma: ctxt still in use? (%d)\n",
1302 		       rdma->sc_ctxt_used);
1303 	if (atomic_read(&rdma->sc_dma_used) != 0)
1304 		pr_err("svcrdma: dma still in use? (%d)\n",
1305 		       atomic_read(&rdma->sc_dma_used));
1306 
1307 	/* Final put of backchannel client transport */
1308 	if (xprt->xpt_bc_xprt) {
1309 		xprt_put(xprt->xpt_bc_xprt);
1310 		xprt->xpt_bc_xprt = NULL;
1311 	}
1312 
1313 	rdma_dealloc_frmr_q(rdma);
1314 	svc_rdma_destroy_ctxts(rdma);
1315 	svc_rdma_destroy_maps(rdma);
1316 
1317 	/* Destroy the QP if present (not a listener) */
1318 	if (rdma->sc_qp && !IS_ERR(rdma->sc_qp))
1319 		ib_destroy_qp(rdma->sc_qp);
1320 
1321 	if (rdma->sc_sq_cq && !IS_ERR(rdma->sc_sq_cq))
1322 		ib_destroy_cq(rdma->sc_sq_cq);
1323 
1324 	if (rdma->sc_rq_cq && !IS_ERR(rdma->sc_rq_cq))
1325 		ib_destroy_cq(rdma->sc_rq_cq);
1326 
1327 	if (rdma->sc_pd && !IS_ERR(rdma->sc_pd))
1328 		ib_dealloc_pd(rdma->sc_pd);
1329 
1330 	/* Destroy the CM ID */
1331 	rdma_destroy_id(rdma->sc_cm_id);
1332 
1333 	kfree(rdma);
1334 }
1335 
1336 static void svc_rdma_free(struct svc_xprt *xprt)
1337 {
1338 	struct svcxprt_rdma *rdma =
1339 		container_of(xprt, struct svcxprt_rdma, sc_xprt);
1340 	INIT_WORK(&rdma->sc_work, __svc_rdma_free);
1341 	queue_work(svc_rdma_wq, &rdma->sc_work);
1342 }
1343 
1344 static int svc_rdma_has_wspace(struct svc_xprt *xprt)
1345 {
1346 	struct svcxprt_rdma *rdma =
1347 		container_of(xprt, struct svcxprt_rdma, sc_xprt);
1348 
1349 	/*
1350 	 * If there are already waiters on the SQ,
1351 	 * return false.
1352 	 */
1353 	if (waitqueue_active(&rdma->sc_send_wait))
1354 		return 0;
1355 
1356 	/* Otherwise return true. */
1357 	return 1;
1358 }
1359 
1360 static int svc_rdma_secure_port(struct svc_rqst *rqstp)
1361 {
1362 	return 1;
1363 }
1364 
1365 int svc_rdma_send(struct svcxprt_rdma *xprt, struct ib_send_wr *wr)
1366 {
1367 	struct ib_send_wr *bad_wr, *n_wr;
1368 	int wr_count;
1369 	int i;
1370 	int ret;
1371 
1372 	if (test_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags))
1373 		return -ENOTCONN;
1374 
1375 	wr_count = 1;
1376 	for (n_wr = wr->next; n_wr; n_wr = n_wr->next)
1377 		wr_count++;
1378 
1379 	/* If the SQ is full, wait until an SQ entry is available */
1380 	while (1) {
1381 		spin_lock_bh(&xprt->sc_lock);
1382 		if (xprt->sc_sq_depth < atomic_read(&xprt->sc_sq_count) + wr_count) {
1383 			spin_unlock_bh(&xprt->sc_lock);
1384 			atomic_inc(&rdma_stat_sq_starve);
1385 
1386 			/* See if we can opportunistically reap SQ WR to make room */
1387 			sq_cq_reap(xprt);
1388 
1389 			/* Wait until SQ WR available if SQ still full */
1390 			wait_event(xprt->sc_send_wait,
1391 				   atomic_read(&xprt->sc_sq_count) <
1392 				   xprt->sc_sq_depth);
1393 			if (test_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags))
1394 				return -ENOTCONN;
1395 			continue;
1396 		}
1397 		/* Take a transport ref for each WR posted */
1398 		for (i = 0; i < wr_count; i++)
1399 			svc_xprt_get(&xprt->sc_xprt);
1400 
1401 		/* Bump used SQ WR count and post */
1402 		atomic_add(wr_count, &xprt->sc_sq_count);
1403 		ret = ib_post_send(xprt->sc_qp, wr, &bad_wr);
1404 		if (ret) {
1405 			set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
1406 			atomic_sub(wr_count, &xprt->sc_sq_count);
1407 			for (i = 0; i < wr_count; i ++)
1408 				svc_xprt_put(&xprt->sc_xprt);
1409 			dprintk("svcrdma: failed to post SQ WR rc=%d, "
1410 			       "sc_sq_count=%d, sc_sq_depth=%d\n",
1411 			       ret, atomic_read(&xprt->sc_sq_count),
1412 			       xprt->sc_sq_depth);
1413 		}
1414 		spin_unlock_bh(&xprt->sc_lock);
1415 		if (ret)
1416 			wake_up(&xprt->sc_send_wait);
1417 		break;
1418 	}
1419 	return ret;
1420 }
1421 
1422 void svc_rdma_send_error(struct svcxprt_rdma *xprt, struct rpcrdma_msg *rmsgp,
1423 			 enum rpcrdma_errcode err)
1424 {
1425 	struct ib_send_wr err_wr;
1426 	struct page *p;
1427 	struct svc_rdma_op_ctxt *ctxt;
1428 	__be32 *va;
1429 	int length;
1430 	int ret;
1431 
1432 	p = alloc_page(GFP_KERNEL);
1433 	if (!p)
1434 		return;
1435 	va = page_address(p);
1436 
1437 	/* XDR encode error */
1438 	length = svc_rdma_xdr_encode_error(xprt, rmsgp, err, va);
1439 
1440 	ctxt = svc_rdma_get_context(xprt);
1441 	ctxt->direction = DMA_FROM_DEVICE;
1442 	ctxt->count = 1;
1443 	ctxt->pages[0] = p;
1444 
1445 	/* Prepare SGE for local address */
1446 	ctxt->sge[0].addr = ib_dma_map_page(xprt->sc_cm_id->device,
1447 					    p, 0, length, DMA_FROM_DEVICE);
1448 	if (ib_dma_mapping_error(xprt->sc_cm_id->device, ctxt->sge[0].addr)) {
1449 		put_page(p);
1450 		svc_rdma_put_context(ctxt, 1);
1451 		return;
1452 	}
1453 	atomic_inc(&xprt->sc_dma_used);
1454 	ctxt->sge[0].lkey = xprt->sc_pd->local_dma_lkey;
1455 	ctxt->sge[0].length = length;
1456 
1457 	/* Prepare SEND WR */
1458 	memset(&err_wr, 0, sizeof err_wr);
1459 	ctxt->wr_op = IB_WR_SEND;
1460 	err_wr.wr_id = (unsigned long)ctxt;
1461 	err_wr.sg_list = ctxt->sge;
1462 	err_wr.num_sge = 1;
1463 	err_wr.opcode = IB_WR_SEND;
1464 	err_wr.send_flags = IB_SEND_SIGNALED;
1465 
1466 	/* Post It */
1467 	ret = svc_rdma_send(xprt, &err_wr);
1468 	if (ret) {
1469 		dprintk("svcrdma: Error %d posting send for protocol error\n",
1470 			ret);
1471 		svc_rdma_unmap_dma(ctxt);
1472 		svc_rdma_put_context(ctxt, 1);
1473 	}
1474 }
1475