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 svc_xprt *svc_rdma_create(struct svc_serv *serv,
60 					struct net *net,
61 					struct sockaddr *sa, int salen,
62 					int flags);
63 static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt);
64 static void svc_rdma_release_rqst(struct svc_rqst *);
65 static void dto_tasklet_func(unsigned long data);
66 static void svc_rdma_detach(struct svc_xprt *xprt);
67 static void svc_rdma_free(struct svc_xprt *xprt);
68 static int svc_rdma_has_wspace(struct svc_xprt *xprt);
69 static int svc_rdma_secure_port(struct svc_rqst *);
70 static void rq_cq_reap(struct svcxprt_rdma *xprt);
71 static void sq_cq_reap(struct svcxprt_rdma *xprt);
72 
73 static DECLARE_TASKLET(dto_tasklet, dto_tasklet_func, 0UL);
74 static DEFINE_SPINLOCK(dto_lock);
75 static LIST_HEAD(dto_xprt_q);
76 
77 static struct svc_xprt_ops svc_rdma_ops = {
78 	.xpo_create = svc_rdma_create,
79 	.xpo_recvfrom = svc_rdma_recvfrom,
80 	.xpo_sendto = svc_rdma_sendto,
81 	.xpo_release_rqst = svc_rdma_release_rqst,
82 	.xpo_detach = svc_rdma_detach,
83 	.xpo_free = svc_rdma_free,
84 	.xpo_prep_reply_hdr = svc_rdma_prep_reply_hdr,
85 	.xpo_has_wspace = svc_rdma_has_wspace,
86 	.xpo_accept = svc_rdma_accept,
87 	.xpo_secure_port = svc_rdma_secure_port,
88 };
89 
90 struct svc_xprt_class svc_rdma_class = {
91 	.xcl_name = "rdma",
92 	.xcl_owner = THIS_MODULE,
93 	.xcl_ops = &svc_rdma_ops,
94 	.xcl_max_payload = RPCSVC_MAXPAYLOAD_TCP,
95 };
96 
97 struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *xprt)
98 {
99 	struct svc_rdma_op_ctxt *ctxt;
100 
101 	while (1) {
102 		ctxt = kmem_cache_alloc(svc_rdma_ctxt_cachep, GFP_KERNEL);
103 		if (ctxt)
104 			break;
105 		schedule_timeout_uninterruptible(msecs_to_jiffies(500));
106 	}
107 	ctxt->xprt = xprt;
108 	INIT_LIST_HEAD(&ctxt->dto_q);
109 	ctxt->count = 0;
110 	ctxt->frmr = NULL;
111 	atomic_inc(&xprt->sc_ctxt_used);
112 	return ctxt;
113 }
114 
115 void svc_rdma_unmap_dma(struct svc_rdma_op_ctxt *ctxt)
116 {
117 	struct svcxprt_rdma *xprt = ctxt->xprt;
118 	int i;
119 	for (i = 0; i < ctxt->count && ctxt->sge[i].length; i++) {
120 		/*
121 		 * Unmap the DMA addr in the SGE if the lkey matches
122 		 * the sc_dma_lkey, otherwise, ignore it since it is
123 		 * an FRMR lkey and will be unmapped later when the
124 		 * last WR that uses it completes.
125 		 */
126 		if (ctxt->sge[i].lkey == xprt->sc_dma_lkey) {
127 			atomic_dec(&xprt->sc_dma_used);
128 			ib_dma_unmap_page(xprt->sc_cm_id->device,
129 					    ctxt->sge[i].addr,
130 					    ctxt->sge[i].length,
131 					    ctxt->direction);
132 		}
133 	}
134 }
135 
136 void svc_rdma_put_context(struct svc_rdma_op_ctxt *ctxt, int free_pages)
137 {
138 	struct svcxprt_rdma *xprt;
139 	int i;
140 
141 	BUG_ON(!ctxt);
142 	xprt = ctxt->xprt;
143 	if (free_pages)
144 		for (i = 0; i < ctxt->count; i++)
145 			put_page(ctxt->pages[i]);
146 
147 	kmem_cache_free(svc_rdma_ctxt_cachep, ctxt);
148 	atomic_dec(&xprt->sc_ctxt_used);
149 }
150 
151 /*
152  * Temporary NFS req mappings are shared across all transport
153  * instances. These are short lived and should be bounded by the number
154  * of concurrent server threads * depth of the SQ.
155  */
156 struct svc_rdma_req_map *svc_rdma_get_req_map(void)
157 {
158 	struct svc_rdma_req_map *map;
159 	while (1) {
160 		map = kmem_cache_alloc(svc_rdma_map_cachep, GFP_KERNEL);
161 		if (map)
162 			break;
163 		schedule_timeout_uninterruptible(msecs_to_jiffies(500));
164 	}
165 	map->count = 0;
166 	return map;
167 }
168 
169 void svc_rdma_put_req_map(struct svc_rdma_req_map *map)
170 {
171 	kmem_cache_free(svc_rdma_map_cachep, map);
172 }
173 
174 /* ib_cq event handler */
175 static void cq_event_handler(struct ib_event *event, void *context)
176 {
177 	struct svc_xprt *xprt = context;
178 	dprintk("svcrdma: received CQ event id=%d, context=%p\n",
179 		event->event, context);
180 	set_bit(XPT_CLOSE, &xprt->xpt_flags);
181 }
182 
183 /* QP event handler */
184 static void qp_event_handler(struct ib_event *event, void *context)
185 {
186 	struct svc_xprt *xprt = context;
187 
188 	switch (event->event) {
189 	/* These are considered benign events */
190 	case IB_EVENT_PATH_MIG:
191 	case IB_EVENT_COMM_EST:
192 	case IB_EVENT_SQ_DRAINED:
193 	case IB_EVENT_QP_LAST_WQE_REACHED:
194 		dprintk("svcrdma: QP event %d received for QP=%p\n",
195 			event->event, event->element.qp);
196 		break;
197 	/* These are considered fatal events */
198 	case IB_EVENT_PATH_MIG_ERR:
199 	case IB_EVENT_QP_FATAL:
200 	case IB_EVENT_QP_REQ_ERR:
201 	case IB_EVENT_QP_ACCESS_ERR:
202 	case IB_EVENT_DEVICE_FATAL:
203 	default:
204 		dprintk("svcrdma: QP ERROR event %d received for QP=%p, "
205 			"closing transport\n",
206 			event->event, event->element.qp);
207 		set_bit(XPT_CLOSE, &xprt->xpt_flags);
208 		break;
209 	}
210 }
211 
212 /*
213  * Data Transfer Operation Tasklet
214  *
215  * Walks a list of transports with I/O pending, removing entries as
216  * they are added to the server's I/O pending list. Two bits indicate
217  * if SQ, RQ, or both have I/O pending. The dto_lock is an irqsave
218  * spinlock that serializes access to the transport list with the RQ
219  * and SQ interrupt handlers.
220  */
221 static void dto_tasklet_func(unsigned long data)
222 {
223 	struct svcxprt_rdma *xprt;
224 	unsigned long flags;
225 
226 	spin_lock_irqsave(&dto_lock, flags);
227 	while (!list_empty(&dto_xprt_q)) {
228 		xprt = list_entry(dto_xprt_q.next,
229 				  struct svcxprt_rdma, sc_dto_q);
230 		list_del_init(&xprt->sc_dto_q);
231 		spin_unlock_irqrestore(&dto_lock, flags);
232 
233 		rq_cq_reap(xprt);
234 		sq_cq_reap(xprt);
235 
236 		svc_xprt_put(&xprt->sc_xprt);
237 		spin_lock_irqsave(&dto_lock, flags);
238 	}
239 	spin_unlock_irqrestore(&dto_lock, flags);
240 }
241 
242 /*
243  * Receive Queue Completion Handler
244  *
245  * Since an RQ completion handler is called on interrupt context, we
246  * need to defer the handling of the I/O to a tasklet
247  */
248 static void rq_comp_handler(struct ib_cq *cq, void *cq_context)
249 {
250 	struct svcxprt_rdma *xprt = cq_context;
251 	unsigned long flags;
252 
253 	/* Guard against unconditional flush call for destroyed QP */
254 	if (atomic_read(&xprt->sc_xprt.xpt_ref.refcount)==0)
255 		return;
256 
257 	/*
258 	 * Set the bit regardless of whether or not it's on the list
259 	 * because it may be on the list already due to an SQ
260 	 * completion.
261 	 */
262 	set_bit(RDMAXPRT_RQ_PENDING, &xprt->sc_flags);
263 
264 	/*
265 	 * If this transport is not already on the DTO transport queue,
266 	 * add it
267 	 */
268 	spin_lock_irqsave(&dto_lock, flags);
269 	if (list_empty(&xprt->sc_dto_q)) {
270 		svc_xprt_get(&xprt->sc_xprt);
271 		list_add_tail(&xprt->sc_dto_q, &dto_xprt_q);
272 	}
273 	spin_unlock_irqrestore(&dto_lock, flags);
274 
275 	/* Tasklet does all the work to avoid irqsave locks. */
276 	tasklet_schedule(&dto_tasklet);
277 }
278 
279 /*
280  * rq_cq_reap - Process the RQ CQ.
281  *
282  * Take all completing WC off the CQE and enqueue the associated DTO
283  * context on the dto_q for the transport.
284  *
285  * Note that caller must hold a transport reference.
286  */
287 static void rq_cq_reap(struct svcxprt_rdma *xprt)
288 {
289 	int ret;
290 	struct ib_wc wc;
291 	struct svc_rdma_op_ctxt *ctxt = NULL;
292 
293 	if (!test_and_clear_bit(RDMAXPRT_RQ_PENDING, &xprt->sc_flags))
294 		return;
295 
296 	ib_req_notify_cq(xprt->sc_rq_cq, IB_CQ_NEXT_COMP);
297 	atomic_inc(&rdma_stat_rq_poll);
298 
299 	while ((ret = ib_poll_cq(xprt->sc_rq_cq, 1, &wc)) > 0) {
300 		ctxt = (struct svc_rdma_op_ctxt *)(unsigned long)wc.wr_id;
301 		ctxt->wc_status = wc.status;
302 		ctxt->byte_len = wc.byte_len;
303 		svc_rdma_unmap_dma(ctxt);
304 		if (wc.status != IB_WC_SUCCESS) {
305 			/* Close the transport */
306 			dprintk("svcrdma: transport closing putting ctxt %p\n", ctxt);
307 			set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
308 			svc_rdma_put_context(ctxt, 1);
309 			svc_xprt_put(&xprt->sc_xprt);
310 			continue;
311 		}
312 		spin_lock_bh(&xprt->sc_rq_dto_lock);
313 		list_add_tail(&ctxt->dto_q, &xprt->sc_rq_dto_q);
314 		spin_unlock_bh(&xprt->sc_rq_dto_lock);
315 		svc_xprt_put(&xprt->sc_xprt);
316 	}
317 
318 	if (ctxt)
319 		atomic_inc(&rdma_stat_rq_prod);
320 
321 	set_bit(XPT_DATA, &xprt->sc_xprt.xpt_flags);
322 	/*
323 	 * If data arrived before established event,
324 	 * don't enqueue. This defers RPC I/O until the
325 	 * RDMA connection is complete.
326 	 */
327 	if (!test_bit(RDMAXPRT_CONN_PENDING, &xprt->sc_flags))
328 		svc_xprt_enqueue(&xprt->sc_xprt);
329 }
330 
331 /*
332  * Process a completion context
333  */
334 static void process_context(struct svcxprt_rdma *xprt,
335 			    struct svc_rdma_op_ctxt *ctxt)
336 {
337 	svc_rdma_unmap_dma(ctxt);
338 
339 	switch (ctxt->wr_op) {
340 	case IB_WR_SEND:
341 		BUG_ON(ctxt->frmr);
342 		svc_rdma_put_context(ctxt, 1);
343 		break;
344 
345 	case IB_WR_RDMA_WRITE:
346 		BUG_ON(ctxt->frmr);
347 		svc_rdma_put_context(ctxt, 0);
348 		break;
349 
350 	case IB_WR_RDMA_READ:
351 	case IB_WR_RDMA_READ_WITH_INV:
352 		svc_rdma_put_frmr(xprt, ctxt->frmr);
353 		if (test_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags)) {
354 			struct svc_rdma_op_ctxt *read_hdr = ctxt->read_hdr;
355 			BUG_ON(!read_hdr);
356 			spin_lock_bh(&xprt->sc_rq_dto_lock);
357 			set_bit(XPT_DATA, &xprt->sc_xprt.xpt_flags);
358 			list_add_tail(&read_hdr->dto_q,
359 				      &xprt->sc_read_complete_q);
360 			spin_unlock_bh(&xprt->sc_rq_dto_lock);
361 			svc_xprt_enqueue(&xprt->sc_xprt);
362 		}
363 		svc_rdma_put_context(ctxt, 0);
364 		break;
365 
366 	default:
367 		BUG_ON(1);
368 		printk(KERN_ERR "svcrdma: unexpected completion type, "
369 		       "opcode=%d\n",
370 		       ctxt->wr_op);
371 		break;
372 	}
373 }
374 
375 /*
376  * Send Queue Completion Handler - potentially called on interrupt context.
377  *
378  * Note that caller must hold a transport reference.
379  */
380 static void sq_cq_reap(struct svcxprt_rdma *xprt)
381 {
382 	struct svc_rdma_op_ctxt *ctxt = NULL;
383 	struct ib_wc wc_a[6];
384 	struct ib_wc *wc;
385 	struct ib_cq *cq = xprt->sc_sq_cq;
386 	int ret;
387 
388 	memset(wc_a, 0, sizeof(wc_a));
389 
390 	if (!test_and_clear_bit(RDMAXPRT_SQ_PENDING, &xprt->sc_flags))
391 		return;
392 
393 	ib_req_notify_cq(xprt->sc_sq_cq, IB_CQ_NEXT_COMP);
394 	atomic_inc(&rdma_stat_sq_poll);
395 	while ((ret = ib_poll_cq(cq, ARRAY_SIZE(wc_a), wc_a)) > 0) {
396 		int i;
397 
398 		for (i = 0; i < ret; i++) {
399 			wc = &wc_a[i];
400 			if (wc->status != IB_WC_SUCCESS) {
401 				dprintk("svcrdma: sq wc err status %d\n",
402 					wc->status);
403 
404 				/* Close the transport */
405 				set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
406 			}
407 
408 			/* Decrement used SQ WR count */
409 			atomic_dec(&xprt->sc_sq_count);
410 			wake_up(&xprt->sc_send_wait);
411 
412 			ctxt = (struct svc_rdma_op_ctxt *)
413 				(unsigned long)wc->wr_id;
414 			if (ctxt)
415 				process_context(xprt, ctxt);
416 
417 			svc_xprt_put(&xprt->sc_xprt);
418 		}
419 	}
420 
421 	if (ctxt)
422 		atomic_inc(&rdma_stat_sq_prod);
423 }
424 
425 static void sq_comp_handler(struct ib_cq *cq, void *cq_context)
426 {
427 	struct svcxprt_rdma *xprt = cq_context;
428 	unsigned long flags;
429 
430 	/* Guard against unconditional flush call for destroyed QP */
431 	if (atomic_read(&xprt->sc_xprt.xpt_ref.refcount)==0)
432 		return;
433 
434 	/*
435 	 * Set the bit regardless of whether or not it's on the list
436 	 * because it may be on the list already due to an RQ
437 	 * completion.
438 	 */
439 	set_bit(RDMAXPRT_SQ_PENDING, &xprt->sc_flags);
440 
441 	/*
442 	 * If this transport is not already on the DTO transport queue,
443 	 * add it
444 	 */
445 	spin_lock_irqsave(&dto_lock, flags);
446 	if (list_empty(&xprt->sc_dto_q)) {
447 		svc_xprt_get(&xprt->sc_xprt);
448 		list_add_tail(&xprt->sc_dto_q, &dto_xprt_q);
449 	}
450 	spin_unlock_irqrestore(&dto_lock, flags);
451 
452 	/* Tasklet does all the work to avoid irqsave locks. */
453 	tasklet_schedule(&dto_tasklet);
454 }
455 
456 static struct svcxprt_rdma *rdma_create_xprt(struct svc_serv *serv,
457 					     int listener)
458 {
459 	struct svcxprt_rdma *cma_xprt = kzalloc(sizeof *cma_xprt, GFP_KERNEL);
460 
461 	if (!cma_xprt)
462 		return NULL;
463 	svc_xprt_init(&init_net, &svc_rdma_class, &cma_xprt->sc_xprt, serv);
464 	INIT_LIST_HEAD(&cma_xprt->sc_accept_q);
465 	INIT_LIST_HEAD(&cma_xprt->sc_dto_q);
466 	INIT_LIST_HEAD(&cma_xprt->sc_rq_dto_q);
467 	INIT_LIST_HEAD(&cma_xprt->sc_read_complete_q);
468 	INIT_LIST_HEAD(&cma_xprt->sc_frmr_q);
469 	init_waitqueue_head(&cma_xprt->sc_send_wait);
470 
471 	spin_lock_init(&cma_xprt->sc_lock);
472 	spin_lock_init(&cma_xprt->sc_rq_dto_lock);
473 	spin_lock_init(&cma_xprt->sc_frmr_q_lock);
474 
475 	cma_xprt->sc_ord = svcrdma_ord;
476 
477 	cma_xprt->sc_max_req_size = svcrdma_max_req_size;
478 	cma_xprt->sc_max_requests = svcrdma_max_requests;
479 	cma_xprt->sc_sq_depth = svcrdma_max_requests * RPCRDMA_SQ_DEPTH_MULT;
480 	atomic_set(&cma_xprt->sc_sq_count, 0);
481 	atomic_set(&cma_xprt->sc_ctxt_used, 0);
482 
483 	if (listener)
484 		set_bit(XPT_LISTENER, &cma_xprt->sc_xprt.xpt_flags);
485 
486 	return cma_xprt;
487 }
488 
489 struct page *svc_rdma_get_page(void)
490 {
491 	struct page *page;
492 
493 	while ((page = alloc_page(GFP_KERNEL)) == NULL) {
494 		/* If we can't get memory, wait a bit and try again */
495 		printk(KERN_INFO "svcrdma: out of memory...retrying in 1s\n");
496 		schedule_timeout_uninterruptible(msecs_to_jiffies(1000));
497 	}
498 	return page;
499 }
500 
501 int svc_rdma_post_recv(struct svcxprt_rdma *xprt)
502 {
503 	struct ib_recv_wr recv_wr, *bad_recv_wr;
504 	struct svc_rdma_op_ctxt *ctxt;
505 	struct page *page;
506 	dma_addr_t pa;
507 	int sge_no;
508 	int buflen;
509 	int ret;
510 
511 	ctxt = svc_rdma_get_context(xprt);
512 	buflen = 0;
513 	ctxt->direction = DMA_FROM_DEVICE;
514 	for (sge_no = 0; buflen < xprt->sc_max_req_size; sge_no++) {
515 		BUG_ON(sge_no >= xprt->sc_max_sge);
516 		page = svc_rdma_get_page();
517 		ctxt->pages[sge_no] = page;
518 		pa = ib_dma_map_page(xprt->sc_cm_id->device,
519 				     page, 0, PAGE_SIZE,
520 				     DMA_FROM_DEVICE);
521 		if (ib_dma_mapping_error(xprt->sc_cm_id->device, pa))
522 			goto err_put_ctxt;
523 		atomic_inc(&xprt->sc_dma_used);
524 		ctxt->sge[sge_no].addr = pa;
525 		ctxt->sge[sge_no].length = PAGE_SIZE;
526 		ctxt->sge[sge_no].lkey = xprt->sc_dma_lkey;
527 		ctxt->count = sge_no + 1;
528 		buflen += PAGE_SIZE;
529 	}
530 	recv_wr.next = NULL;
531 	recv_wr.sg_list = &ctxt->sge[0];
532 	recv_wr.num_sge = ctxt->count;
533 	recv_wr.wr_id = (u64)(unsigned long)ctxt;
534 
535 	svc_xprt_get(&xprt->sc_xprt);
536 	ret = ib_post_recv(xprt->sc_qp, &recv_wr, &bad_recv_wr);
537 	if (ret) {
538 		svc_rdma_unmap_dma(ctxt);
539 		svc_rdma_put_context(ctxt, 1);
540 		svc_xprt_put(&xprt->sc_xprt);
541 	}
542 	return ret;
543 
544  err_put_ctxt:
545 	svc_rdma_unmap_dma(ctxt);
546 	svc_rdma_put_context(ctxt, 1);
547 	return -ENOMEM;
548 }
549 
550 /*
551  * This function handles the CONNECT_REQUEST event on a listening
552  * endpoint. It is passed the cma_id for the _new_ connection. The context in
553  * this cma_id is inherited from the listening cma_id and is the svc_xprt
554  * structure for the listening endpoint.
555  *
556  * This function creates a new xprt for the new connection and enqueues it on
557  * the accept queue for the listent xprt. When the listen thread is kicked, it
558  * will call the recvfrom method on the listen xprt which will accept the new
559  * connection.
560  */
561 static void handle_connect_req(struct rdma_cm_id *new_cma_id, size_t client_ird)
562 {
563 	struct svcxprt_rdma *listen_xprt = new_cma_id->context;
564 	struct svcxprt_rdma *newxprt;
565 	struct sockaddr *sa;
566 
567 	/* Create a new transport */
568 	newxprt = rdma_create_xprt(listen_xprt->sc_xprt.xpt_server, 0);
569 	if (!newxprt) {
570 		dprintk("svcrdma: failed to create new transport\n");
571 		return;
572 	}
573 	newxprt->sc_cm_id = new_cma_id;
574 	new_cma_id->context = newxprt;
575 	dprintk("svcrdma: Creating newxprt=%p, cm_id=%p, listenxprt=%p\n",
576 		newxprt, newxprt->sc_cm_id, listen_xprt);
577 
578 	/* Save client advertised inbound read limit for use later in accept. */
579 	newxprt->sc_ord = client_ird;
580 
581 	/* Set the local and remote addresses in the transport */
582 	sa = (struct sockaddr *)&newxprt->sc_cm_id->route.addr.dst_addr;
583 	svc_xprt_set_remote(&newxprt->sc_xprt, sa, svc_addr_len(sa));
584 	sa = (struct sockaddr *)&newxprt->sc_cm_id->route.addr.src_addr;
585 	svc_xprt_set_local(&newxprt->sc_xprt, sa, svc_addr_len(sa));
586 
587 	/*
588 	 * Enqueue the new transport on the accept queue of the listening
589 	 * transport
590 	 */
591 	spin_lock_bh(&listen_xprt->sc_lock);
592 	list_add_tail(&newxprt->sc_accept_q, &listen_xprt->sc_accept_q);
593 	spin_unlock_bh(&listen_xprt->sc_lock);
594 
595 	set_bit(XPT_CONN, &listen_xprt->sc_xprt.xpt_flags);
596 	svc_xprt_enqueue(&listen_xprt->sc_xprt);
597 }
598 
599 /*
600  * Handles events generated on the listening endpoint. These events will be
601  * either be incoming connect requests or adapter removal  events.
602  */
603 static int rdma_listen_handler(struct rdma_cm_id *cma_id,
604 			       struct rdma_cm_event *event)
605 {
606 	struct svcxprt_rdma *xprt = cma_id->context;
607 	int ret = 0;
608 
609 	switch (event->event) {
610 	case RDMA_CM_EVENT_CONNECT_REQUEST:
611 		dprintk("svcrdma: Connect request on cma_id=%p, xprt = %p, "
612 			"event=%d\n", cma_id, cma_id->context, event->event);
613 		handle_connect_req(cma_id,
614 				   event->param.conn.initiator_depth);
615 		break;
616 
617 	case RDMA_CM_EVENT_ESTABLISHED:
618 		/* Accept complete */
619 		dprintk("svcrdma: Connection completed on LISTEN xprt=%p, "
620 			"cm_id=%p\n", xprt, cma_id);
621 		break;
622 
623 	case RDMA_CM_EVENT_DEVICE_REMOVAL:
624 		dprintk("svcrdma: Device removal xprt=%p, cm_id=%p\n",
625 			xprt, cma_id);
626 		if (xprt)
627 			set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
628 		break;
629 
630 	default:
631 		dprintk("svcrdma: Unexpected event on listening endpoint %p, "
632 			"event=%d\n", cma_id, event->event);
633 		break;
634 	}
635 
636 	return ret;
637 }
638 
639 static int rdma_cma_handler(struct rdma_cm_id *cma_id,
640 			    struct rdma_cm_event *event)
641 {
642 	struct svc_xprt *xprt = cma_id->context;
643 	struct svcxprt_rdma *rdma =
644 		container_of(xprt, struct svcxprt_rdma, sc_xprt);
645 	switch (event->event) {
646 	case RDMA_CM_EVENT_ESTABLISHED:
647 		/* Accept complete */
648 		svc_xprt_get(xprt);
649 		dprintk("svcrdma: Connection completed on DTO xprt=%p, "
650 			"cm_id=%p\n", xprt, cma_id);
651 		clear_bit(RDMAXPRT_CONN_PENDING, &rdma->sc_flags);
652 		svc_xprt_enqueue(xprt);
653 		break;
654 	case RDMA_CM_EVENT_DISCONNECTED:
655 		dprintk("svcrdma: Disconnect on DTO xprt=%p, cm_id=%p\n",
656 			xprt, cma_id);
657 		if (xprt) {
658 			set_bit(XPT_CLOSE, &xprt->xpt_flags);
659 			svc_xprt_enqueue(xprt);
660 			svc_xprt_put(xprt);
661 		}
662 		break;
663 	case RDMA_CM_EVENT_DEVICE_REMOVAL:
664 		dprintk("svcrdma: Device removal cma_id=%p, xprt = %p, "
665 			"event=%d\n", cma_id, xprt, event->event);
666 		if (xprt) {
667 			set_bit(XPT_CLOSE, &xprt->xpt_flags);
668 			svc_xprt_enqueue(xprt);
669 		}
670 		break;
671 	default:
672 		dprintk("svcrdma: Unexpected event on DTO endpoint %p, "
673 			"event=%d\n", cma_id, event->event);
674 		break;
675 	}
676 	return 0;
677 }
678 
679 /*
680  * Create a listening RDMA service endpoint.
681  */
682 static struct svc_xprt *svc_rdma_create(struct svc_serv *serv,
683 					struct net *net,
684 					struct sockaddr *sa, int salen,
685 					int flags)
686 {
687 	struct rdma_cm_id *listen_id;
688 	struct svcxprt_rdma *cma_xprt;
689 	struct svc_xprt *xprt;
690 	int ret;
691 
692 	dprintk("svcrdma: Creating RDMA socket\n");
693 	if (sa->sa_family != AF_INET) {
694 		dprintk("svcrdma: Address family %d is not supported.\n", sa->sa_family);
695 		return ERR_PTR(-EAFNOSUPPORT);
696 	}
697 	cma_xprt = rdma_create_xprt(serv, 1);
698 	if (!cma_xprt)
699 		return ERR_PTR(-ENOMEM);
700 	xprt = &cma_xprt->sc_xprt;
701 
702 	listen_id = rdma_create_id(rdma_listen_handler, cma_xprt, RDMA_PS_TCP,
703 				   IB_QPT_RC);
704 	if (IS_ERR(listen_id)) {
705 		ret = PTR_ERR(listen_id);
706 		dprintk("svcrdma: rdma_create_id failed = %d\n", ret);
707 		goto err0;
708 	}
709 
710 	ret = rdma_bind_addr(listen_id, sa);
711 	if (ret) {
712 		dprintk("svcrdma: rdma_bind_addr failed = %d\n", ret);
713 		goto err1;
714 	}
715 	cma_xprt->sc_cm_id = listen_id;
716 
717 	ret = rdma_listen(listen_id, RPCRDMA_LISTEN_BACKLOG);
718 	if (ret) {
719 		dprintk("svcrdma: rdma_listen failed = %d\n", ret);
720 		goto err1;
721 	}
722 
723 	/*
724 	 * We need to use the address from the cm_id in case the
725 	 * caller specified 0 for the port number.
726 	 */
727 	sa = (struct sockaddr *)&cma_xprt->sc_cm_id->route.addr.src_addr;
728 	svc_xprt_set_local(&cma_xprt->sc_xprt, sa, salen);
729 
730 	return &cma_xprt->sc_xprt;
731 
732  err1:
733 	rdma_destroy_id(listen_id);
734  err0:
735 	kfree(cma_xprt);
736 	return ERR_PTR(ret);
737 }
738 
739 static struct svc_rdma_fastreg_mr *rdma_alloc_frmr(struct svcxprt_rdma *xprt)
740 {
741 	struct ib_mr *mr;
742 	struct ib_fast_reg_page_list *pl;
743 	struct svc_rdma_fastreg_mr *frmr;
744 
745 	frmr = kmalloc(sizeof(*frmr), GFP_KERNEL);
746 	if (!frmr)
747 		goto err;
748 
749 	mr = ib_alloc_fast_reg_mr(xprt->sc_pd, RPCSVC_MAXPAGES);
750 	if (IS_ERR(mr))
751 		goto err_free_frmr;
752 
753 	pl = ib_alloc_fast_reg_page_list(xprt->sc_cm_id->device,
754 					 RPCSVC_MAXPAGES);
755 	if (IS_ERR(pl))
756 		goto err_free_mr;
757 
758 	frmr->mr = mr;
759 	frmr->page_list = pl;
760 	INIT_LIST_HEAD(&frmr->frmr_list);
761 	return frmr;
762 
763  err_free_mr:
764 	ib_dereg_mr(mr);
765  err_free_frmr:
766 	kfree(frmr);
767  err:
768 	return ERR_PTR(-ENOMEM);
769 }
770 
771 static void rdma_dealloc_frmr_q(struct svcxprt_rdma *xprt)
772 {
773 	struct svc_rdma_fastreg_mr *frmr;
774 
775 	while (!list_empty(&xprt->sc_frmr_q)) {
776 		frmr = list_entry(xprt->sc_frmr_q.next,
777 				  struct svc_rdma_fastreg_mr, frmr_list);
778 		list_del_init(&frmr->frmr_list);
779 		ib_dereg_mr(frmr->mr);
780 		ib_free_fast_reg_page_list(frmr->page_list);
781 		kfree(frmr);
782 	}
783 }
784 
785 struct svc_rdma_fastreg_mr *svc_rdma_get_frmr(struct svcxprt_rdma *rdma)
786 {
787 	struct svc_rdma_fastreg_mr *frmr = NULL;
788 
789 	spin_lock_bh(&rdma->sc_frmr_q_lock);
790 	if (!list_empty(&rdma->sc_frmr_q)) {
791 		frmr = list_entry(rdma->sc_frmr_q.next,
792 				  struct svc_rdma_fastreg_mr, frmr_list);
793 		list_del_init(&frmr->frmr_list);
794 		frmr->map_len = 0;
795 		frmr->page_list_len = 0;
796 	}
797 	spin_unlock_bh(&rdma->sc_frmr_q_lock);
798 	if (frmr)
799 		return frmr;
800 
801 	return rdma_alloc_frmr(rdma);
802 }
803 
804 static void frmr_unmap_dma(struct svcxprt_rdma *xprt,
805 			   struct svc_rdma_fastreg_mr *frmr)
806 {
807 	int page_no;
808 	for (page_no = 0; page_no < frmr->page_list_len; page_no++) {
809 		dma_addr_t addr = frmr->page_list->page_list[page_no];
810 		if (ib_dma_mapping_error(frmr->mr->device, addr))
811 			continue;
812 		atomic_dec(&xprt->sc_dma_used);
813 		ib_dma_unmap_page(frmr->mr->device, addr, PAGE_SIZE,
814 				  frmr->direction);
815 	}
816 }
817 
818 void svc_rdma_put_frmr(struct svcxprt_rdma *rdma,
819 		       struct svc_rdma_fastreg_mr *frmr)
820 {
821 	if (frmr) {
822 		frmr_unmap_dma(rdma, frmr);
823 		spin_lock_bh(&rdma->sc_frmr_q_lock);
824 		BUG_ON(!list_empty(&frmr->frmr_list));
825 		list_add(&frmr->frmr_list, &rdma->sc_frmr_q);
826 		spin_unlock_bh(&rdma->sc_frmr_q_lock);
827 	}
828 }
829 
830 /*
831  * This is the xpo_recvfrom function for listening endpoints. Its
832  * purpose is to accept incoming connections. The CMA callback handler
833  * has already created a new transport and attached it to the new CMA
834  * ID.
835  *
836  * There is a queue of pending connections hung on the listening
837  * transport. This queue contains the new svc_xprt structure. This
838  * function takes svc_xprt structures off the accept_q and completes
839  * the connection.
840  */
841 static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
842 {
843 	struct svcxprt_rdma *listen_rdma;
844 	struct svcxprt_rdma *newxprt = NULL;
845 	struct rdma_conn_param conn_param;
846 	struct ib_qp_init_attr qp_attr;
847 	struct ib_device_attr devattr;
848 	int uninitialized_var(dma_mr_acc);
849 	int need_dma_mr;
850 	int ret;
851 	int i;
852 
853 	listen_rdma = container_of(xprt, struct svcxprt_rdma, sc_xprt);
854 	clear_bit(XPT_CONN, &xprt->xpt_flags);
855 	/* Get the next entry off the accept list */
856 	spin_lock_bh(&listen_rdma->sc_lock);
857 	if (!list_empty(&listen_rdma->sc_accept_q)) {
858 		newxprt = list_entry(listen_rdma->sc_accept_q.next,
859 				     struct svcxprt_rdma, sc_accept_q);
860 		list_del_init(&newxprt->sc_accept_q);
861 	}
862 	if (!list_empty(&listen_rdma->sc_accept_q))
863 		set_bit(XPT_CONN, &listen_rdma->sc_xprt.xpt_flags);
864 	spin_unlock_bh(&listen_rdma->sc_lock);
865 	if (!newxprt)
866 		return NULL;
867 
868 	dprintk("svcrdma: newxprt from accept queue = %p, cm_id=%p\n",
869 		newxprt, newxprt->sc_cm_id);
870 
871 	ret = ib_query_device(newxprt->sc_cm_id->device, &devattr);
872 	if (ret) {
873 		dprintk("svcrdma: could not query device attributes on "
874 			"device %p, rc=%d\n", newxprt->sc_cm_id->device, ret);
875 		goto errout;
876 	}
877 
878 	/* Qualify the transport resource defaults with the
879 	 * capabilities of this particular device */
880 	newxprt->sc_max_sge = min((size_t)devattr.max_sge,
881 				  (size_t)RPCSVC_MAXPAGES);
882 	newxprt->sc_max_requests = min((size_t)devattr.max_qp_wr,
883 				   (size_t)svcrdma_max_requests);
884 	newxprt->sc_sq_depth = RPCRDMA_SQ_DEPTH_MULT * newxprt->sc_max_requests;
885 
886 	/*
887 	 * Limit ORD based on client limit, local device limit, and
888 	 * configured svcrdma limit.
889 	 */
890 	newxprt->sc_ord = min_t(size_t, devattr.max_qp_rd_atom, newxprt->sc_ord);
891 	newxprt->sc_ord = min_t(size_t,	svcrdma_ord, newxprt->sc_ord);
892 
893 	newxprt->sc_pd = ib_alloc_pd(newxprt->sc_cm_id->device);
894 	if (IS_ERR(newxprt->sc_pd)) {
895 		dprintk("svcrdma: error creating PD for connect request\n");
896 		goto errout;
897 	}
898 	newxprt->sc_sq_cq = ib_create_cq(newxprt->sc_cm_id->device,
899 					 sq_comp_handler,
900 					 cq_event_handler,
901 					 newxprt,
902 					 newxprt->sc_sq_depth,
903 					 0);
904 	if (IS_ERR(newxprt->sc_sq_cq)) {
905 		dprintk("svcrdma: error creating SQ CQ for connect request\n");
906 		goto errout;
907 	}
908 	newxprt->sc_rq_cq = ib_create_cq(newxprt->sc_cm_id->device,
909 					 rq_comp_handler,
910 					 cq_event_handler,
911 					 newxprt,
912 					 newxprt->sc_max_requests,
913 					 0);
914 	if (IS_ERR(newxprt->sc_rq_cq)) {
915 		dprintk("svcrdma: error creating RQ CQ for connect request\n");
916 		goto errout;
917 	}
918 
919 	memset(&qp_attr, 0, sizeof qp_attr);
920 	qp_attr.event_handler = qp_event_handler;
921 	qp_attr.qp_context = &newxprt->sc_xprt;
922 	qp_attr.cap.max_send_wr = newxprt->sc_sq_depth;
923 	qp_attr.cap.max_recv_wr = newxprt->sc_max_requests;
924 	qp_attr.cap.max_send_sge = newxprt->sc_max_sge;
925 	qp_attr.cap.max_recv_sge = newxprt->sc_max_sge;
926 	qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
927 	qp_attr.qp_type = IB_QPT_RC;
928 	qp_attr.send_cq = newxprt->sc_sq_cq;
929 	qp_attr.recv_cq = newxprt->sc_rq_cq;
930 	dprintk("svcrdma: newxprt->sc_cm_id=%p, newxprt->sc_pd=%p\n"
931 		"    cm_id->device=%p, sc_pd->device=%p\n"
932 		"    cap.max_send_wr = %d\n"
933 		"    cap.max_recv_wr = %d\n"
934 		"    cap.max_send_sge = %d\n"
935 		"    cap.max_recv_sge = %d\n",
936 		newxprt->sc_cm_id, newxprt->sc_pd,
937 		newxprt->sc_cm_id->device, newxprt->sc_pd->device,
938 		qp_attr.cap.max_send_wr,
939 		qp_attr.cap.max_recv_wr,
940 		qp_attr.cap.max_send_sge,
941 		qp_attr.cap.max_recv_sge);
942 
943 	ret = rdma_create_qp(newxprt->sc_cm_id, newxprt->sc_pd, &qp_attr);
944 	if (ret) {
945 		/*
946 		 * XXX: This is a hack. We need a xx_request_qp interface
947 		 * that will adjust the qp_attr's with a best-effort
948 		 * number
949 		 */
950 		qp_attr.cap.max_send_sge -= 2;
951 		qp_attr.cap.max_recv_sge -= 2;
952 		ret = rdma_create_qp(newxprt->sc_cm_id, newxprt->sc_pd,
953 				     &qp_attr);
954 		if (ret) {
955 			dprintk("svcrdma: failed to create QP, ret=%d\n", ret);
956 			goto errout;
957 		}
958 		newxprt->sc_max_sge = qp_attr.cap.max_send_sge;
959 		newxprt->sc_max_sge = qp_attr.cap.max_recv_sge;
960 		newxprt->sc_sq_depth = qp_attr.cap.max_send_wr;
961 		newxprt->sc_max_requests = qp_attr.cap.max_recv_wr;
962 	}
963 	newxprt->sc_qp = newxprt->sc_cm_id->qp;
964 
965 	/*
966 	 * Use the most secure set of MR resources based on the
967 	 * transport type and available memory management features in
968 	 * the device. Here's the table implemented below:
969 	 *
970 	 *		Fast	Global	DMA	Remote WR
971 	 *		Reg	LKEY	MR	Access
972 	 *		Sup'd	Sup'd	Needed	Needed
973 	 *
974 	 * IWARP	N	N	Y	Y
975 	 *		N	Y	Y	Y
976 	 *		Y	N	Y	N
977 	 *		Y	Y	N	-
978 	 *
979 	 * IB		N	N	Y	N
980 	 *		N	Y	N	-
981 	 *		Y	N	Y	N
982 	 *		Y	Y	N	-
983 	 *
984 	 * NB:	iWARP requires remote write access for the data sink
985 	 *	of an RDMA_READ. IB does not.
986 	 */
987 	if (devattr.device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS) {
988 		newxprt->sc_frmr_pg_list_len =
989 			devattr.max_fast_reg_page_list_len;
990 		newxprt->sc_dev_caps |= SVCRDMA_DEVCAP_FAST_REG;
991 	}
992 
993 	/*
994 	 * Determine if a DMA MR is required and if so, what privs are required
995 	 */
996 	switch (rdma_node_get_transport(newxprt->sc_cm_id->device->node_type)) {
997 	case RDMA_TRANSPORT_IWARP:
998 		newxprt->sc_dev_caps |= SVCRDMA_DEVCAP_READ_W_INV;
999 		if (!(newxprt->sc_dev_caps & SVCRDMA_DEVCAP_FAST_REG)) {
1000 			need_dma_mr = 1;
1001 			dma_mr_acc =
1002 				(IB_ACCESS_LOCAL_WRITE |
1003 				 IB_ACCESS_REMOTE_WRITE);
1004 		} else if (!(devattr.device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY)) {
1005 			need_dma_mr = 1;
1006 			dma_mr_acc = IB_ACCESS_LOCAL_WRITE;
1007 		} else
1008 			need_dma_mr = 0;
1009 		break;
1010 	case RDMA_TRANSPORT_IB:
1011 		if (!(newxprt->sc_dev_caps & SVCRDMA_DEVCAP_FAST_REG)) {
1012 			need_dma_mr = 1;
1013 			dma_mr_acc = IB_ACCESS_LOCAL_WRITE;
1014 		} else if (!(devattr.device_cap_flags &
1015 			     IB_DEVICE_LOCAL_DMA_LKEY)) {
1016 			need_dma_mr = 1;
1017 			dma_mr_acc = IB_ACCESS_LOCAL_WRITE;
1018 		} else
1019 			need_dma_mr = 0;
1020 		break;
1021 	default:
1022 		goto errout;
1023 	}
1024 
1025 	/* Create the DMA MR if needed, otherwise, use the DMA LKEY */
1026 	if (need_dma_mr) {
1027 		/* Register all of physical memory */
1028 		newxprt->sc_phys_mr =
1029 			ib_get_dma_mr(newxprt->sc_pd, dma_mr_acc);
1030 		if (IS_ERR(newxprt->sc_phys_mr)) {
1031 			dprintk("svcrdma: Failed to create DMA MR ret=%d\n",
1032 				ret);
1033 			goto errout;
1034 		}
1035 		newxprt->sc_dma_lkey = newxprt->sc_phys_mr->lkey;
1036 	} else
1037 		newxprt->sc_dma_lkey =
1038 			newxprt->sc_cm_id->device->local_dma_lkey;
1039 
1040 	/* Post receive buffers */
1041 	for (i = 0; i < newxprt->sc_max_requests; i++) {
1042 		ret = svc_rdma_post_recv(newxprt);
1043 		if (ret) {
1044 			dprintk("svcrdma: failure posting receive buffers\n");
1045 			goto errout;
1046 		}
1047 	}
1048 
1049 	/* Swap out the handler */
1050 	newxprt->sc_cm_id->event_handler = rdma_cma_handler;
1051 
1052 	/*
1053 	 * Arm the CQs for the SQ and RQ before accepting so we can't
1054 	 * miss the first message
1055 	 */
1056 	ib_req_notify_cq(newxprt->sc_sq_cq, IB_CQ_NEXT_COMP);
1057 	ib_req_notify_cq(newxprt->sc_rq_cq, IB_CQ_NEXT_COMP);
1058 
1059 	/* Accept Connection */
1060 	set_bit(RDMAXPRT_CONN_PENDING, &newxprt->sc_flags);
1061 	memset(&conn_param, 0, sizeof conn_param);
1062 	conn_param.responder_resources = 0;
1063 	conn_param.initiator_depth = newxprt->sc_ord;
1064 	ret = rdma_accept(newxprt->sc_cm_id, &conn_param);
1065 	if (ret) {
1066 		dprintk("svcrdma: failed to accept new connection, ret=%d\n",
1067 		       ret);
1068 		goto errout;
1069 	}
1070 
1071 	dprintk("svcrdma: new connection %p accepted with the following "
1072 		"attributes:\n"
1073 		"    local_ip        : %pI4\n"
1074 		"    local_port	     : %d\n"
1075 		"    remote_ip       : %pI4\n"
1076 		"    remote_port     : %d\n"
1077 		"    max_sge         : %d\n"
1078 		"    sq_depth        : %d\n"
1079 		"    max_requests    : %d\n"
1080 		"    ord             : %d\n",
1081 		newxprt,
1082 		&((struct sockaddr_in *)&newxprt->sc_cm_id->
1083 			 route.addr.src_addr)->sin_addr.s_addr,
1084 		ntohs(((struct sockaddr_in *)&newxprt->sc_cm_id->
1085 		       route.addr.src_addr)->sin_port),
1086 		&((struct sockaddr_in *)&newxprt->sc_cm_id->
1087 			 route.addr.dst_addr)->sin_addr.s_addr,
1088 		ntohs(((struct sockaddr_in *)&newxprt->sc_cm_id->
1089 		       route.addr.dst_addr)->sin_port),
1090 		newxprt->sc_max_sge,
1091 		newxprt->sc_sq_depth,
1092 		newxprt->sc_max_requests,
1093 		newxprt->sc_ord);
1094 
1095 	return &newxprt->sc_xprt;
1096 
1097  errout:
1098 	dprintk("svcrdma: failure accepting new connection rc=%d.\n", ret);
1099 	/* Take a reference in case the DTO handler runs */
1100 	svc_xprt_get(&newxprt->sc_xprt);
1101 	if (newxprt->sc_qp && !IS_ERR(newxprt->sc_qp))
1102 		ib_destroy_qp(newxprt->sc_qp);
1103 	rdma_destroy_id(newxprt->sc_cm_id);
1104 	/* This call to put will destroy the transport */
1105 	svc_xprt_put(&newxprt->sc_xprt);
1106 	return NULL;
1107 }
1108 
1109 static void svc_rdma_release_rqst(struct svc_rqst *rqstp)
1110 {
1111 }
1112 
1113 /*
1114  * When connected, an svc_xprt has at least two references:
1115  *
1116  * - A reference held by the cm_id between the ESTABLISHED and
1117  *   DISCONNECTED events. If the remote peer disconnected first, this
1118  *   reference could be gone.
1119  *
1120  * - A reference held by the svc_recv code that called this function
1121  *   as part of close processing.
1122  *
1123  * At a minimum one references should still be held.
1124  */
1125 static void svc_rdma_detach(struct svc_xprt *xprt)
1126 {
1127 	struct svcxprt_rdma *rdma =
1128 		container_of(xprt, struct svcxprt_rdma, sc_xprt);
1129 	dprintk("svc: svc_rdma_detach(%p)\n", xprt);
1130 
1131 	/* Disconnect and flush posted WQE */
1132 	rdma_disconnect(rdma->sc_cm_id);
1133 }
1134 
1135 static void __svc_rdma_free(struct work_struct *work)
1136 {
1137 	struct svcxprt_rdma *rdma =
1138 		container_of(work, struct svcxprt_rdma, sc_work);
1139 	dprintk("svcrdma: svc_rdma_free(%p)\n", rdma);
1140 
1141 	/* We should only be called from kref_put */
1142 	BUG_ON(atomic_read(&rdma->sc_xprt.xpt_ref.refcount) != 0);
1143 
1144 	/*
1145 	 * Destroy queued, but not processed read completions. Note
1146 	 * that this cleanup has to be done before destroying the
1147 	 * cm_id because the device ptr is needed to unmap the dma in
1148 	 * svc_rdma_put_context.
1149 	 */
1150 	while (!list_empty(&rdma->sc_read_complete_q)) {
1151 		struct svc_rdma_op_ctxt *ctxt;
1152 		ctxt = list_entry(rdma->sc_read_complete_q.next,
1153 				  struct svc_rdma_op_ctxt,
1154 				  dto_q);
1155 		list_del_init(&ctxt->dto_q);
1156 		svc_rdma_put_context(ctxt, 1);
1157 	}
1158 
1159 	/* Destroy queued, but not processed recv completions */
1160 	while (!list_empty(&rdma->sc_rq_dto_q)) {
1161 		struct svc_rdma_op_ctxt *ctxt;
1162 		ctxt = list_entry(rdma->sc_rq_dto_q.next,
1163 				  struct svc_rdma_op_ctxt,
1164 				  dto_q);
1165 		list_del_init(&ctxt->dto_q);
1166 		svc_rdma_put_context(ctxt, 1);
1167 	}
1168 
1169 	/* Warn if we leaked a resource or under-referenced */
1170 	WARN_ON(atomic_read(&rdma->sc_ctxt_used) != 0);
1171 	WARN_ON(atomic_read(&rdma->sc_dma_used) != 0);
1172 
1173 	/* De-allocate fastreg mr */
1174 	rdma_dealloc_frmr_q(rdma);
1175 
1176 	/* Destroy the QP if present (not a listener) */
1177 	if (rdma->sc_qp && !IS_ERR(rdma->sc_qp))
1178 		ib_destroy_qp(rdma->sc_qp);
1179 
1180 	if (rdma->sc_sq_cq && !IS_ERR(rdma->sc_sq_cq))
1181 		ib_destroy_cq(rdma->sc_sq_cq);
1182 
1183 	if (rdma->sc_rq_cq && !IS_ERR(rdma->sc_rq_cq))
1184 		ib_destroy_cq(rdma->sc_rq_cq);
1185 
1186 	if (rdma->sc_phys_mr && !IS_ERR(rdma->sc_phys_mr))
1187 		ib_dereg_mr(rdma->sc_phys_mr);
1188 
1189 	if (rdma->sc_pd && !IS_ERR(rdma->sc_pd))
1190 		ib_dealloc_pd(rdma->sc_pd);
1191 
1192 	/* Destroy the CM ID */
1193 	rdma_destroy_id(rdma->sc_cm_id);
1194 
1195 	kfree(rdma);
1196 }
1197 
1198 static void svc_rdma_free(struct svc_xprt *xprt)
1199 {
1200 	struct svcxprt_rdma *rdma =
1201 		container_of(xprt, struct svcxprt_rdma, sc_xprt);
1202 	INIT_WORK(&rdma->sc_work, __svc_rdma_free);
1203 	queue_work(svc_rdma_wq, &rdma->sc_work);
1204 }
1205 
1206 static int svc_rdma_has_wspace(struct svc_xprt *xprt)
1207 {
1208 	struct svcxprt_rdma *rdma =
1209 		container_of(xprt, struct svcxprt_rdma, sc_xprt);
1210 
1211 	/*
1212 	 * If there are already waiters on the SQ,
1213 	 * return false.
1214 	 */
1215 	if (waitqueue_active(&rdma->sc_send_wait))
1216 		return 0;
1217 
1218 	/* Otherwise return true. */
1219 	return 1;
1220 }
1221 
1222 static int svc_rdma_secure_port(struct svc_rqst *rqstp)
1223 {
1224 	return 1;
1225 }
1226 
1227 /*
1228  * Attempt to register the kvec representing the RPC memory with the
1229  * device.
1230  *
1231  * Returns:
1232  *  NULL : The device does not support fastreg or there were no more
1233  *         fastreg mr.
1234  *  frmr : The kvec register request was successfully posted.
1235  *    <0 : An error was encountered attempting to register the kvec.
1236  */
1237 int svc_rdma_fastreg(struct svcxprt_rdma *xprt,
1238 		     struct svc_rdma_fastreg_mr *frmr)
1239 {
1240 	struct ib_send_wr fastreg_wr;
1241 	u8 key;
1242 
1243 	/* Bump the key */
1244 	key = (u8)(frmr->mr->lkey & 0x000000FF);
1245 	ib_update_fast_reg_key(frmr->mr, ++key);
1246 
1247 	/* Prepare FASTREG WR */
1248 	memset(&fastreg_wr, 0, sizeof fastreg_wr);
1249 	fastreg_wr.opcode = IB_WR_FAST_REG_MR;
1250 	fastreg_wr.send_flags = IB_SEND_SIGNALED;
1251 	fastreg_wr.wr.fast_reg.iova_start = (unsigned long)frmr->kva;
1252 	fastreg_wr.wr.fast_reg.page_list = frmr->page_list;
1253 	fastreg_wr.wr.fast_reg.page_list_len = frmr->page_list_len;
1254 	fastreg_wr.wr.fast_reg.page_shift = PAGE_SHIFT;
1255 	fastreg_wr.wr.fast_reg.length = frmr->map_len;
1256 	fastreg_wr.wr.fast_reg.access_flags = frmr->access_flags;
1257 	fastreg_wr.wr.fast_reg.rkey = frmr->mr->lkey;
1258 	return svc_rdma_send(xprt, &fastreg_wr);
1259 }
1260 
1261 int svc_rdma_send(struct svcxprt_rdma *xprt, struct ib_send_wr *wr)
1262 {
1263 	struct ib_send_wr *bad_wr, *n_wr;
1264 	int wr_count;
1265 	int i;
1266 	int ret;
1267 
1268 	if (test_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags))
1269 		return -ENOTCONN;
1270 
1271 	BUG_ON(wr->send_flags != IB_SEND_SIGNALED);
1272 	wr_count = 1;
1273 	for (n_wr = wr->next; n_wr; n_wr = n_wr->next)
1274 		wr_count++;
1275 
1276 	/* If the SQ is full, wait until an SQ entry is available */
1277 	while (1) {
1278 		spin_lock_bh(&xprt->sc_lock);
1279 		if (xprt->sc_sq_depth < atomic_read(&xprt->sc_sq_count) + wr_count) {
1280 			spin_unlock_bh(&xprt->sc_lock);
1281 			atomic_inc(&rdma_stat_sq_starve);
1282 
1283 			/* See if we can opportunistically reap SQ WR to make room */
1284 			sq_cq_reap(xprt);
1285 
1286 			/* Wait until SQ WR available if SQ still full */
1287 			wait_event(xprt->sc_send_wait,
1288 				   atomic_read(&xprt->sc_sq_count) <
1289 				   xprt->sc_sq_depth);
1290 			if (test_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags))
1291 				return -ENOTCONN;
1292 			continue;
1293 		}
1294 		/* Take a transport ref for each WR posted */
1295 		for (i = 0; i < wr_count; i++)
1296 			svc_xprt_get(&xprt->sc_xprt);
1297 
1298 		/* Bump used SQ WR count and post */
1299 		atomic_add(wr_count, &xprt->sc_sq_count);
1300 		ret = ib_post_send(xprt->sc_qp, wr, &bad_wr);
1301 		if (ret) {
1302 			set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
1303 			atomic_sub(wr_count, &xprt->sc_sq_count);
1304 			for (i = 0; i < wr_count; i ++)
1305 				svc_xprt_put(&xprt->sc_xprt);
1306 			dprintk("svcrdma: failed to post SQ WR rc=%d, "
1307 			       "sc_sq_count=%d, sc_sq_depth=%d\n",
1308 			       ret, atomic_read(&xprt->sc_sq_count),
1309 			       xprt->sc_sq_depth);
1310 		}
1311 		spin_unlock_bh(&xprt->sc_lock);
1312 		if (ret)
1313 			wake_up(&xprt->sc_send_wait);
1314 		break;
1315 	}
1316 	return ret;
1317 }
1318 
1319 void svc_rdma_send_error(struct svcxprt_rdma *xprt, struct rpcrdma_msg *rmsgp,
1320 			 enum rpcrdma_errcode err)
1321 {
1322 	struct ib_send_wr err_wr;
1323 	struct page *p;
1324 	struct svc_rdma_op_ctxt *ctxt;
1325 	u32 *va;
1326 	int length;
1327 	int ret;
1328 
1329 	p = svc_rdma_get_page();
1330 	va = page_address(p);
1331 
1332 	/* XDR encode error */
1333 	length = svc_rdma_xdr_encode_error(xprt, rmsgp, err, va);
1334 
1335 	ctxt = svc_rdma_get_context(xprt);
1336 	ctxt->direction = DMA_FROM_DEVICE;
1337 	ctxt->count = 1;
1338 	ctxt->pages[0] = p;
1339 
1340 	/* Prepare SGE for local address */
1341 	ctxt->sge[0].addr = ib_dma_map_page(xprt->sc_cm_id->device,
1342 					    p, 0, length, DMA_FROM_DEVICE);
1343 	if (ib_dma_mapping_error(xprt->sc_cm_id->device, ctxt->sge[0].addr)) {
1344 		put_page(p);
1345 		svc_rdma_put_context(ctxt, 1);
1346 		return;
1347 	}
1348 	atomic_inc(&xprt->sc_dma_used);
1349 	ctxt->sge[0].lkey = xprt->sc_dma_lkey;
1350 	ctxt->sge[0].length = length;
1351 
1352 	/* Prepare SEND WR */
1353 	memset(&err_wr, 0, sizeof err_wr);
1354 	ctxt->wr_op = IB_WR_SEND;
1355 	err_wr.wr_id = (unsigned long)ctxt;
1356 	err_wr.sg_list = ctxt->sge;
1357 	err_wr.num_sge = 1;
1358 	err_wr.opcode = IB_WR_SEND;
1359 	err_wr.send_flags = IB_SEND_SIGNALED;
1360 
1361 	/* Post It */
1362 	ret = svc_rdma_send(xprt, &err_wr);
1363 	if (ret) {
1364 		dprintk("svcrdma: Error %d posting send for protocol error\n",
1365 			ret);
1366 		svc_rdma_unmap_dma(ctxt);
1367 		svc_rdma_put_context(ctxt, 1);
1368 	}
1369 }
1370