1 /*
2  * Copyright (c) 2005-2007 Network Appliance, Inc. All rights reserved.
3  *
4  * This software is available to you under a choice of one of two
5  * licenses.  You may choose to be licensed under the terms of the GNU
6  * General Public License (GPL) Version 2, available from the file
7  * COPYING in the main directory of this source tree, or the BSD-type
8  * license below:
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  *
14  *      Redistributions of source code must retain the above copyright
15  *      notice, this list of conditions and the following disclaimer.
16  *
17  *      Redistributions in binary form must reproduce the above
18  *      copyright notice, this list of conditions and the following
19  *      disclaimer in the documentation and/or other materials provided
20  *      with the distribution.
21  *
22  *      Neither the name of the Network Appliance, Inc. nor the names of
23  *      its contributors may be used to endorse or promote products
24  *      derived from this software without specific prior written
25  *      permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
28  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
29  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
30  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
31  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
32  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
33  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
34  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
35  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
36  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
37  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
38  *
39  * Author: Tom Tucker <tom@opengridcomputing.com>
40  */
41 
42 #include <linux/sunrpc/svc_xprt.h>
43 #include <linux/sunrpc/debug.h>
44 #include <linux/sunrpc/rpc_rdma.h>
45 #include <linux/spinlock.h>
46 #include <rdma/ib_verbs.h>
47 #include <rdma/rdma_cm.h>
48 #include <linux/sunrpc/svc_rdma.h>
49 
50 #define RPCDBG_FACILITY	RPCDBG_SVCXPRT
51 
52 static struct svc_xprt *svc_rdma_create(struct svc_serv *serv,
53 					struct sockaddr *sa, int salen,
54 					int flags);
55 static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt);
56 static void svc_rdma_release_rqst(struct svc_rqst *);
57 static void dto_tasklet_func(unsigned long data);
58 static void svc_rdma_detach(struct svc_xprt *xprt);
59 static void svc_rdma_free(struct svc_xprt *xprt);
60 static int svc_rdma_has_wspace(struct svc_xprt *xprt);
61 static void rq_cq_reap(struct svcxprt_rdma *xprt);
62 static void sq_cq_reap(struct svcxprt_rdma *xprt);
63 
64 DECLARE_TASKLET(dto_tasklet, dto_tasklet_func, 0UL);
65 static DEFINE_SPINLOCK(dto_lock);
66 static LIST_HEAD(dto_xprt_q);
67 
68 static struct svc_xprt_ops svc_rdma_ops = {
69 	.xpo_create = svc_rdma_create,
70 	.xpo_recvfrom = svc_rdma_recvfrom,
71 	.xpo_sendto = svc_rdma_sendto,
72 	.xpo_release_rqst = svc_rdma_release_rqst,
73 	.xpo_detach = svc_rdma_detach,
74 	.xpo_free = svc_rdma_free,
75 	.xpo_prep_reply_hdr = svc_rdma_prep_reply_hdr,
76 	.xpo_has_wspace = svc_rdma_has_wspace,
77 	.xpo_accept = svc_rdma_accept,
78 };
79 
80 struct svc_xprt_class svc_rdma_class = {
81 	.xcl_name = "rdma",
82 	.xcl_owner = THIS_MODULE,
83 	.xcl_ops = &svc_rdma_ops,
84 	.xcl_max_payload = RPCSVC_MAXPAYLOAD_TCP,
85 };
86 
87 /* WR context cache. Created in svc_rdma.c  */
88 extern struct kmem_cache *svc_rdma_ctxt_cachep;
89 
90 struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *xprt)
91 {
92 	struct svc_rdma_op_ctxt *ctxt;
93 
94 	while (1) {
95 		ctxt = kmem_cache_alloc(svc_rdma_ctxt_cachep, GFP_KERNEL);
96 		if (ctxt)
97 			break;
98 		schedule_timeout_uninterruptible(msecs_to_jiffies(500));
99 	}
100 	ctxt->xprt = xprt;
101 	INIT_LIST_HEAD(&ctxt->dto_q);
102 	ctxt->count = 0;
103 	ctxt->frmr = NULL;
104 	atomic_inc(&xprt->sc_ctxt_used);
105 	return ctxt;
106 }
107 
108 void svc_rdma_unmap_dma(struct svc_rdma_op_ctxt *ctxt)
109 {
110 	struct svcxprt_rdma *xprt = ctxt->xprt;
111 	int i;
112 	for (i = 0; i < ctxt->count && ctxt->sge[i].length; i++) {
113 		/*
114 		 * Unmap the DMA addr in the SGE if the lkey matches
115 		 * the sc_dma_lkey, otherwise, ignore it since it is
116 		 * an FRMR lkey and will be unmapped later when the
117 		 * last WR that uses it completes.
118 		 */
119 		if (ctxt->sge[i].lkey == xprt->sc_dma_lkey) {
120 			atomic_dec(&xprt->sc_dma_used);
121 			ib_dma_unmap_single(xprt->sc_cm_id->device,
122 					    ctxt->sge[i].addr,
123 					    ctxt->sge[i].length,
124 					    ctxt->direction);
125 		}
126 	}
127 }
128 
129 void svc_rdma_put_context(struct svc_rdma_op_ctxt *ctxt, int free_pages)
130 {
131 	struct svcxprt_rdma *xprt;
132 	int i;
133 
134 	BUG_ON(!ctxt);
135 	xprt = ctxt->xprt;
136 	if (free_pages)
137 		for (i = 0; i < ctxt->count; i++)
138 			put_page(ctxt->pages[i]);
139 
140 	kmem_cache_free(svc_rdma_ctxt_cachep, ctxt);
141 	atomic_dec(&xprt->sc_ctxt_used);
142 }
143 
144 /* Temporary NFS request map cache. Created in svc_rdma.c  */
145 extern struct kmem_cache *svc_rdma_map_cachep;
146 
147 /*
148  * Temporary NFS req mappings are shared across all transport
149  * instances. These are short lived and should be bounded by the number
150  * of concurrent server threads * depth of the SQ.
151  */
152 struct svc_rdma_req_map *svc_rdma_get_req_map(void)
153 {
154 	struct svc_rdma_req_map *map;
155 	while (1) {
156 		map = kmem_cache_alloc(svc_rdma_map_cachep, GFP_KERNEL);
157 		if (map)
158 			break;
159 		schedule_timeout_uninterruptible(msecs_to_jiffies(500));
160 	}
161 	map->count = 0;
162 	map->frmr = NULL;
163 	return map;
164 }
165 
166 void svc_rdma_put_req_map(struct svc_rdma_req_map *map)
167 {
168 	kmem_cache_free(svc_rdma_map_cachep, map);
169 }
170 
171 /* ib_cq event handler */
172 static void cq_event_handler(struct ib_event *event, void *context)
173 {
174 	struct svc_xprt *xprt = context;
175 	dprintk("svcrdma: received CQ event id=%d, context=%p\n",
176 		event->event, context);
177 	set_bit(XPT_CLOSE, &xprt->xpt_flags);
178 }
179 
180 /* QP event handler */
181 static void qp_event_handler(struct ib_event *event, void *context)
182 {
183 	struct svc_xprt *xprt = context;
184 
185 	switch (event->event) {
186 	/* These are considered benign events */
187 	case IB_EVENT_PATH_MIG:
188 	case IB_EVENT_COMM_EST:
189 	case IB_EVENT_SQ_DRAINED:
190 	case IB_EVENT_QP_LAST_WQE_REACHED:
191 		dprintk("svcrdma: QP event %d received for QP=%p\n",
192 			event->event, event->element.qp);
193 		break;
194 	/* These are considered fatal events */
195 	case IB_EVENT_PATH_MIG_ERR:
196 	case IB_EVENT_QP_FATAL:
197 	case IB_EVENT_QP_REQ_ERR:
198 	case IB_EVENT_QP_ACCESS_ERR:
199 	case IB_EVENT_DEVICE_FATAL:
200 	default:
201 		dprintk("svcrdma: QP ERROR event %d received for QP=%p, "
202 			"closing transport\n",
203 			event->event, event->element.qp);
204 		set_bit(XPT_CLOSE, &xprt->xpt_flags);
205 		break;
206 	}
207 }
208 
209 /*
210  * Data Transfer Operation Tasklet
211  *
212  * Walks a list of transports with I/O pending, removing entries as
213  * they are added to the server's I/O pending list. Two bits indicate
214  * if SQ, RQ, or both have I/O pending. The dto_lock is an irqsave
215  * spinlock that serializes access to the transport list with the RQ
216  * and SQ interrupt handlers.
217  */
218 static void dto_tasklet_func(unsigned long data)
219 {
220 	struct svcxprt_rdma *xprt;
221 	unsigned long flags;
222 
223 	spin_lock_irqsave(&dto_lock, flags);
224 	while (!list_empty(&dto_xprt_q)) {
225 		xprt = list_entry(dto_xprt_q.next,
226 				  struct svcxprt_rdma, sc_dto_q);
227 		list_del_init(&xprt->sc_dto_q);
228 		spin_unlock_irqrestore(&dto_lock, flags);
229 
230 		rq_cq_reap(xprt);
231 		sq_cq_reap(xprt);
232 
233 		svc_xprt_put(&xprt->sc_xprt);
234 		spin_lock_irqsave(&dto_lock, flags);
235 	}
236 	spin_unlock_irqrestore(&dto_lock, flags);
237 }
238 
239 /*
240  * Receive Queue Completion Handler
241  *
242  * Since an RQ completion handler is called on interrupt context, we
243  * need to defer the handling of the I/O to a tasklet
244  */
245 static void rq_comp_handler(struct ib_cq *cq, void *cq_context)
246 {
247 	struct svcxprt_rdma *xprt = cq_context;
248 	unsigned long flags;
249 
250 	/* Guard against unconditional flush call for destroyed QP */
251 	if (atomic_read(&xprt->sc_xprt.xpt_ref.refcount)==0)
252 		return;
253 
254 	/*
255 	 * Set the bit regardless of whether or not it's on the list
256 	 * because it may be on the list already due to an SQ
257 	 * completion.
258 	 */
259 	set_bit(RDMAXPRT_RQ_PENDING, &xprt->sc_flags);
260 
261 	/*
262 	 * If this transport is not already on the DTO transport queue,
263 	 * add it
264 	 */
265 	spin_lock_irqsave(&dto_lock, flags);
266 	if (list_empty(&xprt->sc_dto_q)) {
267 		svc_xprt_get(&xprt->sc_xprt);
268 		list_add_tail(&xprt->sc_dto_q, &dto_xprt_q);
269 	}
270 	spin_unlock_irqrestore(&dto_lock, flags);
271 
272 	/* Tasklet does all the work to avoid irqsave locks. */
273 	tasklet_schedule(&dto_tasklet);
274 }
275 
276 /*
277  * rq_cq_reap - Process the RQ CQ.
278  *
279  * Take all completing WC off the CQE and enqueue the associated DTO
280  * context on the dto_q for the transport.
281  *
282  * Note that caller must hold a transport reference.
283  */
284 static void rq_cq_reap(struct svcxprt_rdma *xprt)
285 {
286 	int ret;
287 	struct ib_wc wc;
288 	struct svc_rdma_op_ctxt *ctxt = NULL;
289 
290 	if (!test_and_clear_bit(RDMAXPRT_RQ_PENDING, &xprt->sc_flags))
291 		return;
292 
293 	ib_req_notify_cq(xprt->sc_rq_cq, IB_CQ_NEXT_COMP);
294 	atomic_inc(&rdma_stat_rq_poll);
295 
296 	while ((ret = ib_poll_cq(xprt->sc_rq_cq, 1, &wc)) > 0) {
297 		ctxt = (struct svc_rdma_op_ctxt *)(unsigned long)wc.wr_id;
298 		ctxt->wc_status = wc.status;
299 		ctxt->byte_len = wc.byte_len;
300 		svc_rdma_unmap_dma(ctxt);
301 		if (wc.status != IB_WC_SUCCESS) {
302 			/* Close the transport */
303 			dprintk("svcrdma: transport closing putting ctxt %p\n", ctxt);
304 			set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
305 			svc_rdma_put_context(ctxt, 1);
306 			svc_xprt_put(&xprt->sc_xprt);
307 			continue;
308 		}
309 		spin_lock_bh(&xprt->sc_rq_dto_lock);
310 		list_add_tail(&ctxt->dto_q, &xprt->sc_rq_dto_q);
311 		spin_unlock_bh(&xprt->sc_rq_dto_lock);
312 		svc_xprt_put(&xprt->sc_xprt);
313 	}
314 
315 	if (ctxt)
316 		atomic_inc(&rdma_stat_rq_prod);
317 
318 	set_bit(XPT_DATA, &xprt->sc_xprt.xpt_flags);
319 	/*
320 	 * If data arrived before established event,
321 	 * don't enqueue. This defers RPC I/O until the
322 	 * RDMA connection is complete.
323 	 */
324 	if (!test_bit(RDMAXPRT_CONN_PENDING, &xprt->sc_flags))
325 		svc_xprt_enqueue(&xprt->sc_xprt);
326 }
327 
328 /*
329  * Processs a completion context
330  */
331 static void process_context(struct svcxprt_rdma *xprt,
332 			    struct svc_rdma_op_ctxt *ctxt)
333 {
334 	svc_rdma_unmap_dma(ctxt);
335 
336 	switch (ctxt->wr_op) {
337 	case IB_WR_SEND:
338 		if (test_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags))
339 			svc_rdma_put_frmr(xprt, ctxt->frmr);
340 		svc_rdma_put_context(ctxt, 1);
341 		break;
342 
343 	case IB_WR_RDMA_WRITE:
344 		svc_rdma_put_context(ctxt, 0);
345 		break;
346 
347 	case IB_WR_RDMA_READ:
348 	case IB_WR_RDMA_READ_WITH_INV:
349 		if (test_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags)) {
350 			struct svc_rdma_op_ctxt *read_hdr = ctxt->read_hdr;
351 			BUG_ON(!read_hdr);
352 			if (test_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags))
353 				svc_rdma_put_frmr(xprt, ctxt->frmr);
354 			spin_lock_bh(&xprt->sc_rq_dto_lock);
355 			set_bit(XPT_DATA, &xprt->sc_xprt.xpt_flags);
356 			list_add_tail(&read_hdr->dto_q,
357 				      &xprt->sc_read_complete_q);
358 			spin_unlock_bh(&xprt->sc_rq_dto_lock);
359 			svc_xprt_enqueue(&xprt->sc_xprt);
360 		}
361 		svc_rdma_put_context(ctxt, 0);
362 		break;
363 
364 	default:
365 		printk(KERN_ERR "svcrdma: unexpected completion type, "
366 		       "opcode=%d\n",
367 		       ctxt->wr_op);
368 		break;
369 	}
370 }
371 
372 /*
373  * Send Queue Completion Handler - potentially called on interrupt context.
374  *
375  * Note that caller must hold a transport reference.
376  */
377 static void sq_cq_reap(struct svcxprt_rdma *xprt)
378 {
379 	struct svc_rdma_op_ctxt *ctxt = NULL;
380 	struct ib_wc wc;
381 	struct ib_cq *cq = xprt->sc_sq_cq;
382 	int ret;
383 
384 	if (!test_and_clear_bit(RDMAXPRT_SQ_PENDING, &xprt->sc_flags))
385 		return;
386 
387 	ib_req_notify_cq(xprt->sc_sq_cq, IB_CQ_NEXT_COMP);
388 	atomic_inc(&rdma_stat_sq_poll);
389 	while ((ret = ib_poll_cq(cq, 1, &wc)) > 0) {
390 		if (wc.status != IB_WC_SUCCESS)
391 			/* Close the transport */
392 			set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
393 
394 		/* Decrement used SQ WR count */
395 		atomic_dec(&xprt->sc_sq_count);
396 		wake_up(&xprt->sc_send_wait);
397 
398 		ctxt = (struct svc_rdma_op_ctxt *)(unsigned long)wc.wr_id;
399 		if (ctxt)
400 			process_context(xprt, ctxt);
401 
402 		svc_xprt_put(&xprt->sc_xprt);
403 	}
404 
405 	if (ctxt)
406 		atomic_inc(&rdma_stat_sq_prod);
407 }
408 
409 static void sq_comp_handler(struct ib_cq *cq, void *cq_context)
410 {
411 	struct svcxprt_rdma *xprt = cq_context;
412 	unsigned long flags;
413 
414 	/* Guard against unconditional flush call for destroyed QP */
415 	if (atomic_read(&xprt->sc_xprt.xpt_ref.refcount)==0)
416 		return;
417 
418 	/*
419 	 * Set the bit regardless of whether or not it's on the list
420 	 * because it may be on the list already due to an RQ
421 	 * completion.
422 	 */
423 	set_bit(RDMAXPRT_SQ_PENDING, &xprt->sc_flags);
424 
425 	/*
426 	 * If this transport is not already on the DTO transport queue,
427 	 * add it
428 	 */
429 	spin_lock_irqsave(&dto_lock, flags);
430 	if (list_empty(&xprt->sc_dto_q)) {
431 		svc_xprt_get(&xprt->sc_xprt);
432 		list_add_tail(&xprt->sc_dto_q, &dto_xprt_q);
433 	}
434 	spin_unlock_irqrestore(&dto_lock, flags);
435 
436 	/* Tasklet does all the work to avoid irqsave locks. */
437 	tasklet_schedule(&dto_tasklet);
438 }
439 
440 static struct svcxprt_rdma *rdma_create_xprt(struct svc_serv *serv,
441 					     int listener)
442 {
443 	struct svcxprt_rdma *cma_xprt = kzalloc(sizeof *cma_xprt, GFP_KERNEL);
444 
445 	if (!cma_xprt)
446 		return NULL;
447 	svc_xprt_init(&svc_rdma_class, &cma_xprt->sc_xprt, serv);
448 	INIT_LIST_HEAD(&cma_xprt->sc_accept_q);
449 	INIT_LIST_HEAD(&cma_xprt->sc_dto_q);
450 	INIT_LIST_HEAD(&cma_xprt->sc_rq_dto_q);
451 	INIT_LIST_HEAD(&cma_xprt->sc_read_complete_q);
452 	INIT_LIST_HEAD(&cma_xprt->sc_frmr_q);
453 	init_waitqueue_head(&cma_xprt->sc_send_wait);
454 
455 	spin_lock_init(&cma_xprt->sc_lock);
456 	spin_lock_init(&cma_xprt->sc_rq_dto_lock);
457 	spin_lock_init(&cma_xprt->sc_frmr_q_lock);
458 
459 	cma_xprt->sc_ord = svcrdma_ord;
460 
461 	cma_xprt->sc_max_req_size = svcrdma_max_req_size;
462 	cma_xprt->sc_max_requests = svcrdma_max_requests;
463 	cma_xprt->sc_sq_depth = svcrdma_max_requests * RPCRDMA_SQ_DEPTH_MULT;
464 	atomic_set(&cma_xprt->sc_sq_count, 0);
465 	atomic_set(&cma_xprt->sc_ctxt_used, 0);
466 
467 	if (listener)
468 		set_bit(XPT_LISTENER, &cma_xprt->sc_xprt.xpt_flags);
469 
470 	return cma_xprt;
471 }
472 
473 struct page *svc_rdma_get_page(void)
474 {
475 	struct page *page;
476 
477 	while ((page = alloc_page(GFP_KERNEL)) == NULL) {
478 		/* If we can't get memory, wait a bit and try again */
479 		printk(KERN_INFO "svcrdma: out of memory...retrying in 1000 "
480 		       "jiffies.\n");
481 		schedule_timeout_uninterruptible(msecs_to_jiffies(1000));
482 	}
483 	return page;
484 }
485 
486 int svc_rdma_post_recv(struct svcxprt_rdma *xprt)
487 {
488 	struct ib_recv_wr recv_wr, *bad_recv_wr;
489 	struct svc_rdma_op_ctxt *ctxt;
490 	struct page *page;
491 	dma_addr_t pa;
492 	int sge_no;
493 	int buflen;
494 	int ret;
495 
496 	ctxt = svc_rdma_get_context(xprt);
497 	buflen = 0;
498 	ctxt->direction = DMA_FROM_DEVICE;
499 	for (sge_no = 0; buflen < xprt->sc_max_req_size; sge_no++) {
500 		BUG_ON(sge_no >= xprt->sc_max_sge);
501 		page = svc_rdma_get_page();
502 		ctxt->pages[sge_no] = page;
503 		pa = ib_dma_map_page(xprt->sc_cm_id->device,
504 				     page, 0, PAGE_SIZE,
505 				     DMA_FROM_DEVICE);
506 		if (ib_dma_mapping_error(xprt->sc_cm_id->device, pa))
507 			goto err_put_ctxt;
508 		atomic_inc(&xprt->sc_dma_used);
509 		ctxt->sge[sge_no].addr = pa;
510 		ctxt->sge[sge_no].length = PAGE_SIZE;
511 		ctxt->sge[sge_no].lkey = xprt->sc_dma_lkey;
512 		buflen += PAGE_SIZE;
513 	}
514 	ctxt->count = sge_no;
515 	recv_wr.next = NULL;
516 	recv_wr.sg_list = &ctxt->sge[0];
517 	recv_wr.num_sge = ctxt->count;
518 	recv_wr.wr_id = (u64)(unsigned long)ctxt;
519 
520 	svc_xprt_get(&xprt->sc_xprt);
521 	ret = ib_post_recv(xprt->sc_qp, &recv_wr, &bad_recv_wr);
522 	if (ret) {
523 		svc_xprt_put(&xprt->sc_xprt);
524 		svc_rdma_put_context(ctxt, 1);
525 	}
526 	return ret;
527 
528  err_put_ctxt:
529 	svc_rdma_put_context(ctxt, 1);
530 	return -ENOMEM;
531 }
532 
533 /*
534  * This function handles the CONNECT_REQUEST event on a listening
535  * endpoint. It is passed the cma_id for the _new_ connection. The context in
536  * this cma_id is inherited from the listening cma_id and is the svc_xprt
537  * structure for the listening endpoint.
538  *
539  * This function creates a new xprt for the new connection and enqueues it on
540  * the accept queue for the listent xprt. When the listen thread is kicked, it
541  * will call the recvfrom method on the listen xprt which will accept the new
542  * connection.
543  */
544 static void handle_connect_req(struct rdma_cm_id *new_cma_id, size_t client_ird)
545 {
546 	struct svcxprt_rdma *listen_xprt = new_cma_id->context;
547 	struct svcxprt_rdma *newxprt;
548 	struct sockaddr *sa;
549 
550 	/* Create a new transport */
551 	newxprt = rdma_create_xprt(listen_xprt->sc_xprt.xpt_server, 0);
552 	if (!newxprt) {
553 		dprintk("svcrdma: failed to create new transport\n");
554 		return;
555 	}
556 	newxprt->sc_cm_id = new_cma_id;
557 	new_cma_id->context = newxprt;
558 	dprintk("svcrdma: Creating newxprt=%p, cm_id=%p, listenxprt=%p\n",
559 		newxprt, newxprt->sc_cm_id, listen_xprt);
560 
561 	/* Save client advertised inbound read limit for use later in accept. */
562 	newxprt->sc_ord = client_ird;
563 
564 	/* Set the local and remote addresses in the transport */
565 	sa = (struct sockaddr *)&newxprt->sc_cm_id->route.addr.dst_addr;
566 	svc_xprt_set_remote(&newxprt->sc_xprt, sa, svc_addr_len(sa));
567 	sa = (struct sockaddr *)&newxprt->sc_cm_id->route.addr.src_addr;
568 	svc_xprt_set_local(&newxprt->sc_xprt, sa, svc_addr_len(sa));
569 
570 	/*
571 	 * Enqueue the new transport on the accept queue of the listening
572 	 * transport
573 	 */
574 	spin_lock_bh(&listen_xprt->sc_lock);
575 	list_add_tail(&newxprt->sc_accept_q, &listen_xprt->sc_accept_q);
576 	spin_unlock_bh(&listen_xprt->sc_lock);
577 
578 	/*
579 	 * Can't use svc_xprt_received here because we are not on a
580 	 * rqstp thread
581 	*/
582 	set_bit(XPT_CONN, &listen_xprt->sc_xprt.xpt_flags);
583 	svc_xprt_enqueue(&listen_xprt->sc_xprt);
584 }
585 
586 /*
587  * Handles events generated on the listening endpoint. These events will be
588  * either be incoming connect requests or adapter removal  events.
589  */
590 static int rdma_listen_handler(struct rdma_cm_id *cma_id,
591 			       struct rdma_cm_event *event)
592 {
593 	struct svcxprt_rdma *xprt = cma_id->context;
594 	int ret = 0;
595 
596 	switch (event->event) {
597 	case RDMA_CM_EVENT_CONNECT_REQUEST:
598 		dprintk("svcrdma: Connect request on cma_id=%p, xprt = %p, "
599 			"event=%d\n", cma_id, cma_id->context, event->event);
600 		handle_connect_req(cma_id,
601 				   event->param.conn.initiator_depth);
602 		break;
603 
604 	case RDMA_CM_EVENT_ESTABLISHED:
605 		/* Accept complete */
606 		dprintk("svcrdma: Connection completed on LISTEN xprt=%p, "
607 			"cm_id=%p\n", xprt, cma_id);
608 		break;
609 
610 	case RDMA_CM_EVENT_DEVICE_REMOVAL:
611 		dprintk("svcrdma: Device removal xprt=%p, cm_id=%p\n",
612 			xprt, cma_id);
613 		if (xprt)
614 			set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
615 		break;
616 
617 	default:
618 		dprintk("svcrdma: Unexpected event on listening endpoint %p, "
619 			"event=%d\n", cma_id, event->event);
620 		break;
621 	}
622 
623 	return ret;
624 }
625 
626 static int rdma_cma_handler(struct rdma_cm_id *cma_id,
627 			    struct rdma_cm_event *event)
628 {
629 	struct svc_xprt *xprt = cma_id->context;
630 	struct svcxprt_rdma *rdma =
631 		container_of(xprt, struct svcxprt_rdma, sc_xprt);
632 	switch (event->event) {
633 	case RDMA_CM_EVENT_ESTABLISHED:
634 		/* Accept complete */
635 		svc_xprt_get(xprt);
636 		dprintk("svcrdma: Connection completed on DTO xprt=%p, "
637 			"cm_id=%p\n", xprt, cma_id);
638 		clear_bit(RDMAXPRT_CONN_PENDING, &rdma->sc_flags);
639 		svc_xprt_enqueue(xprt);
640 		break;
641 	case RDMA_CM_EVENT_DISCONNECTED:
642 		dprintk("svcrdma: Disconnect on DTO xprt=%p, cm_id=%p\n",
643 			xprt, cma_id);
644 		if (xprt) {
645 			set_bit(XPT_CLOSE, &xprt->xpt_flags);
646 			svc_xprt_enqueue(xprt);
647 			svc_xprt_put(xprt);
648 		}
649 		break;
650 	case RDMA_CM_EVENT_DEVICE_REMOVAL:
651 		dprintk("svcrdma: Device removal cma_id=%p, xprt = %p, "
652 			"event=%d\n", cma_id, xprt, event->event);
653 		if (xprt) {
654 			set_bit(XPT_CLOSE, &xprt->xpt_flags);
655 			svc_xprt_enqueue(xprt);
656 		}
657 		break;
658 	default:
659 		dprintk("svcrdma: Unexpected event on DTO endpoint %p, "
660 			"event=%d\n", cma_id, event->event);
661 		break;
662 	}
663 	return 0;
664 }
665 
666 /*
667  * Create a listening RDMA service endpoint.
668  */
669 static struct svc_xprt *svc_rdma_create(struct svc_serv *serv,
670 					struct sockaddr *sa, int salen,
671 					int flags)
672 {
673 	struct rdma_cm_id *listen_id;
674 	struct svcxprt_rdma *cma_xprt;
675 	struct svc_xprt *xprt;
676 	int ret;
677 
678 	dprintk("svcrdma: Creating RDMA socket\n");
679 
680 	cma_xprt = rdma_create_xprt(serv, 1);
681 	if (!cma_xprt)
682 		return ERR_PTR(-ENOMEM);
683 	xprt = &cma_xprt->sc_xprt;
684 
685 	listen_id = rdma_create_id(rdma_listen_handler, cma_xprt, RDMA_PS_TCP);
686 	if (IS_ERR(listen_id)) {
687 		ret = PTR_ERR(listen_id);
688 		dprintk("svcrdma: rdma_create_id failed = %d\n", ret);
689 		goto err0;
690 	}
691 
692 	ret = rdma_bind_addr(listen_id, sa);
693 	if (ret) {
694 		dprintk("svcrdma: rdma_bind_addr failed = %d\n", ret);
695 		goto err1;
696 	}
697 	cma_xprt->sc_cm_id = listen_id;
698 
699 	ret = rdma_listen(listen_id, RPCRDMA_LISTEN_BACKLOG);
700 	if (ret) {
701 		dprintk("svcrdma: rdma_listen failed = %d\n", ret);
702 		goto err1;
703 	}
704 
705 	/*
706 	 * We need to use the address from the cm_id in case the
707 	 * caller specified 0 for the port number.
708 	 */
709 	sa = (struct sockaddr *)&cma_xprt->sc_cm_id->route.addr.src_addr;
710 	svc_xprt_set_local(&cma_xprt->sc_xprt, sa, salen);
711 
712 	return &cma_xprt->sc_xprt;
713 
714  err1:
715 	rdma_destroy_id(listen_id);
716  err0:
717 	kfree(cma_xprt);
718 	return ERR_PTR(ret);
719 }
720 
721 static struct svc_rdma_fastreg_mr *rdma_alloc_frmr(struct svcxprt_rdma *xprt)
722 {
723 	struct ib_mr *mr;
724 	struct ib_fast_reg_page_list *pl;
725 	struct svc_rdma_fastreg_mr *frmr;
726 
727 	frmr = kmalloc(sizeof(*frmr), GFP_KERNEL);
728 	if (!frmr)
729 		goto err;
730 
731 	mr = ib_alloc_fast_reg_mr(xprt->sc_pd, RPCSVC_MAXPAGES);
732 	if (!mr)
733 		goto err_free_frmr;
734 
735 	pl = ib_alloc_fast_reg_page_list(xprt->sc_cm_id->device,
736 					 RPCSVC_MAXPAGES);
737 	if (!pl)
738 		goto err_free_mr;
739 
740 	frmr->mr = mr;
741 	frmr->page_list = pl;
742 	INIT_LIST_HEAD(&frmr->frmr_list);
743 	return frmr;
744 
745  err_free_mr:
746 	ib_dereg_mr(mr);
747  err_free_frmr:
748 	kfree(frmr);
749  err:
750 	return ERR_PTR(-ENOMEM);
751 }
752 
753 static void rdma_dealloc_frmr_q(struct svcxprt_rdma *xprt)
754 {
755 	struct svc_rdma_fastreg_mr *frmr;
756 
757 	while (!list_empty(&xprt->sc_frmr_q)) {
758 		frmr = list_entry(xprt->sc_frmr_q.next,
759 				  struct svc_rdma_fastreg_mr, frmr_list);
760 		list_del_init(&frmr->frmr_list);
761 		ib_dereg_mr(frmr->mr);
762 		ib_free_fast_reg_page_list(frmr->page_list);
763 		kfree(frmr);
764 	}
765 }
766 
767 struct svc_rdma_fastreg_mr *svc_rdma_get_frmr(struct svcxprt_rdma *rdma)
768 {
769 	struct svc_rdma_fastreg_mr *frmr = NULL;
770 
771 	spin_lock_bh(&rdma->sc_frmr_q_lock);
772 	if (!list_empty(&rdma->sc_frmr_q)) {
773 		frmr = list_entry(rdma->sc_frmr_q.next,
774 				  struct svc_rdma_fastreg_mr, frmr_list);
775 		list_del_init(&frmr->frmr_list);
776 		frmr->map_len = 0;
777 		frmr->page_list_len = 0;
778 	}
779 	spin_unlock_bh(&rdma->sc_frmr_q_lock);
780 	if (frmr)
781 		return frmr;
782 
783 	return rdma_alloc_frmr(rdma);
784 }
785 
786 static void frmr_unmap_dma(struct svcxprt_rdma *xprt,
787 			   struct svc_rdma_fastreg_mr *frmr)
788 {
789 	int page_no;
790 	for (page_no = 0; page_no < frmr->page_list_len; page_no++) {
791 		dma_addr_t addr = frmr->page_list->page_list[page_no];
792 		if (ib_dma_mapping_error(frmr->mr->device, addr))
793 			continue;
794 		atomic_dec(&xprt->sc_dma_used);
795 		ib_dma_unmap_single(frmr->mr->device, addr, PAGE_SIZE,
796 				    frmr->direction);
797 	}
798 }
799 
800 void svc_rdma_put_frmr(struct svcxprt_rdma *rdma,
801 		       struct svc_rdma_fastreg_mr *frmr)
802 {
803 	if (frmr) {
804 		frmr_unmap_dma(rdma, frmr);
805 		spin_lock_bh(&rdma->sc_frmr_q_lock);
806 		BUG_ON(!list_empty(&frmr->frmr_list));
807 		list_add(&frmr->frmr_list, &rdma->sc_frmr_q);
808 		spin_unlock_bh(&rdma->sc_frmr_q_lock);
809 	}
810 }
811 
812 /*
813  * This is the xpo_recvfrom function for listening endpoints. Its
814  * purpose is to accept incoming connections. The CMA callback handler
815  * has already created a new transport and attached it to the new CMA
816  * ID.
817  *
818  * There is a queue of pending connections hung on the listening
819  * transport. This queue contains the new svc_xprt structure. This
820  * function takes svc_xprt structures off the accept_q and completes
821  * the connection.
822  */
823 static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
824 {
825 	struct svcxprt_rdma *listen_rdma;
826 	struct svcxprt_rdma *newxprt = NULL;
827 	struct rdma_conn_param conn_param;
828 	struct ib_qp_init_attr qp_attr;
829 	struct ib_device_attr devattr;
830 	int dma_mr_acc;
831 	int need_dma_mr;
832 	int ret;
833 	int i;
834 
835 	listen_rdma = container_of(xprt, struct svcxprt_rdma, sc_xprt);
836 	clear_bit(XPT_CONN, &xprt->xpt_flags);
837 	/* Get the next entry off the accept list */
838 	spin_lock_bh(&listen_rdma->sc_lock);
839 	if (!list_empty(&listen_rdma->sc_accept_q)) {
840 		newxprt = list_entry(listen_rdma->sc_accept_q.next,
841 				     struct svcxprt_rdma, sc_accept_q);
842 		list_del_init(&newxprt->sc_accept_q);
843 	}
844 	if (!list_empty(&listen_rdma->sc_accept_q))
845 		set_bit(XPT_CONN, &listen_rdma->sc_xprt.xpt_flags);
846 	spin_unlock_bh(&listen_rdma->sc_lock);
847 	if (!newxprt)
848 		return NULL;
849 
850 	dprintk("svcrdma: newxprt from accept queue = %p, cm_id=%p\n",
851 		newxprt, newxprt->sc_cm_id);
852 
853 	ret = ib_query_device(newxprt->sc_cm_id->device, &devattr);
854 	if (ret) {
855 		dprintk("svcrdma: could not query device attributes on "
856 			"device %p, rc=%d\n", newxprt->sc_cm_id->device, ret);
857 		goto errout;
858 	}
859 
860 	/* Qualify the transport resource defaults with the
861 	 * capabilities of this particular device */
862 	newxprt->sc_max_sge = min((size_t)devattr.max_sge,
863 				  (size_t)RPCSVC_MAXPAGES);
864 	newxprt->sc_max_requests = min((size_t)devattr.max_qp_wr,
865 				   (size_t)svcrdma_max_requests);
866 	newxprt->sc_sq_depth = RPCRDMA_SQ_DEPTH_MULT * newxprt->sc_max_requests;
867 
868 	/*
869 	 * Limit ORD based on client limit, local device limit, and
870 	 * configured svcrdma limit.
871 	 */
872 	newxprt->sc_ord = min_t(size_t, devattr.max_qp_rd_atom, newxprt->sc_ord);
873 	newxprt->sc_ord = min_t(size_t,	svcrdma_ord, newxprt->sc_ord);
874 
875 	newxprt->sc_pd = ib_alloc_pd(newxprt->sc_cm_id->device);
876 	if (IS_ERR(newxprt->sc_pd)) {
877 		dprintk("svcrdma: error creating PD for connect request\n");
878 		goto errout;
879 	}
880 	newxprt->sc_sq_cq = ib_create_cq(newxprt->sc_cm_id->device,
881 					 sq_comp_handler,
882 					 cq_event_handler,
883 					 newxprt,
884 					 newxprt->sc_sq_depth,
885 					 0);
886 	if (IS_ERR(newxprt->sc_sq_cq)) {
887 		dprintk("svcrdma: error creating SQ CQ for connect request\n");
888 		goto errout;
889 	}
890 	newxprt->sc_rq_cq = ib_create_cq(newxprt->sc_cm_id->device,
891 					 rq_comp_handler,
892 					 cq_event_handler,
893 					 newxprt,
894 					 newxprt->sc_max_requests,
895 					 0);
896 	if (IS_ERR(newxprt->sc_rq_cq)) {
897 		dprintk("svcrdma: error creating RQ CQ for connect request\n");
898 		goto errout;
899 	}
900 
901 	memset(&qp_attr, 0, sizeof qp_attr);
902 	qp_attr.event_handler = qp_event_handler;
903 	qp_attr.qp_context = &newxprt->sc_xprt;
904 	qp_attr.cap.max_send_wr = newxprt->sc_sq_depth;
905 	qp_attr.cap.max_recv_wr = newxprt->sc_max_requests;
906 	qp_attr.cap.max_send_sge = newxprt->sc_max_sge;
907 	qp_attr.cap.max_recv_sge = newxprt->sc_max_sge;
908 	qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
909 	qp_attr.qp_type = IB_QPT_RC;
910 	qp_attr.send_cq = newxprt->sc_sq_cq;
911 	qp_attr.recv_cq = newxprt->sc_rq_cq;
912 	dprintk("svcrdma: newxprt->sc_cm_id=%p, newxprt->sc_pd=%p\n"
913 		"    cm_id->device=%p, sc_pd->device=%p\n"
914 		"    cap.max_send_wr = %d\n"
915 		"    cap.max_recv_wr = %d\n"
916 		"    cap.max_send_sge = %d\n"
917 		"    cap.max_recv_sge = %d\n",
918 		newxprt->sc_cm_id, newxprt->sc_pd,
919 		newxprt->sc_cm_id->device, newxprt->sc_pd->device,
920 		qp_attr.cap.max_send_wr,
921 		qp_attr.cap.max_recv_wr,
922 		qp_attr.cap.max_send_sge,
923 		qp_attr.cap.max_recv_sge);
924 
925 	ret = rdma_create_qp(newxprt->sc_cm_id, newxprt->sc_pd, &qp_attr);
926 	if (ret) {
927 		/*
928 		 * XXX: This is a hack. We need a xx_request_qp interface
929 		 * that will adjust the qp_attr's with a best-effort
930 		 * number
931 		 */
932 		qp_attr.cap.max_send_sge -= 2;
933 		qp_attr.cap.max_recv_sge -= 2;
934 		ret = rdma_create_qp(newxprt->sc_cm_id, newxprt->sc_pd,
935 				     &qp_attr);
936 		if (ret) {
937 			dprintk("svcrdma: failed to create QP, ret=%d\n", ret);
938 			goto errout;
939 		}
940 		newxprt->sc_max_sge = qp_attr.cap.max_send_sge;
941 		newxprt->sc_max_sge = qp_attr.cap.max_recv_sge;
942 		newxprt->sc_sq_depth = qp_attr.cap.max_send_wr;
943 		newxprt->sc_max_requests = qp_attr.cap.max_recv_wr;
944 	}
945 	newxprt->sc_qp = newxprt->sc_cm_id->qp;
946 
947 	/*
948 	 * Use the most secure set of MR resources based on the
949 	 * transport type and available memory management features in
950 	 * the device. Here's the table implemented below:
951 	 *
952 	 *		Fast	Global	DMA	Remote WR
953 	 *		Reg	LKEY	MR	Access
954 	 *		Sup'd	Sup'd	Needed	Needed
955 	 *
956 	 * IWARP	N	N	Y	Y
957 	 *		N	Y	Y	Y
958 	 *		Y	N	Y	N
959 	 *		Y	Y	N	-
960 	 *
961 	 * IB		N	N	Y	N
962 	 *		N	Y	N	-
963 	 *		Y	N	Y	N
964 	 *		Y	Y	N	-
965 	 *
966 	 * NB:	iWARP requires remote write access for the data sink
967 	 *	of an RDMA_READ. IB does not.
968 	 */
969 	if (devattr.device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS) {
970 		newxprt->sc_frmr_pg_list_len =
971 			devattr.max_fast_reg_page_list_len;
972 		newxprt->sc_dev_caps |= SVCRDMA_DEVCAP_FAST_REG;
973 	}
974 
975 	/*
976 	 * Determine if a DMA MR is required and if so, what privs are required
977 	 */
978 	switch (rdma_node_get_transport(newxprt->sc_cm_id->device->node_type)) {
979 	case RDMA_TRANSPORT_IWARP:
980 		newxprt->sc_dev_caps |= SVCRDMA_DEVCAP_READ_W_INV;
981 		if (!(newxprt->sc_dev_caps & SVCRDMA_DEVCAP_FAST_REG)) {
982 			need_dma_mr = 1;
983 			dma_mr_acc =
984 				(IB_ACCESS_LOCAL_WRITE |
985 				 IB_ACCESS_REMOTE_WRITE);
986 		} else if (!(devattr.device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY)) {
987 			need_dma_mr = 1;
988 			dma_mr_acc = IB_ACCESS_LOCAL_WRITE;
989 		} else
990 			need_dma_mr = 0;
991 		break;
992 	case RDMA_TRANSPORT_IB:
993 		if (!(devattr.device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY)) {
994 			need_dma_mr = 1;
995 			dma_mr_acc = IB_ACCESS_LOCAL_WRITE;
996 		} else
997 			need_dma_mr = 0;
998 		break;
999 	default:
1000 		goto errout;
1001 	}
1002 
1003 	/* Create the DMA MR if needed, otherwise, use the DMA LKEY */
1004 	if (need_dma_mr) {
1005 		/* Register all of physical memory */
1006 		newxprt->sc_phys_mr =
1007 			ib_get_dma_mr(newxprt->sc_pd, dma_mr_acc);
1008 		if (IS_ERR(newxprt->sc_phys_mr)) {
1009 			dprintk("svcrdma: Failed to create DMA MR ret=%d\n",
1010 				ret);
1011 			goto errout;
1012 		}
1013 		newxprt->sc_dma_lkey = newxprt->sc_phys_mr->lkey;
1014 	} else
1015 		newxprt->sc_dma_lkey =
1016 			newxprt->sc_cm_id->device->local_dma_lkey;
1017 
1018 	/* Post receive buffers */
1019 	for (i = 0; i < newxprt->sc_max_requests; i++) {
1020 		ret = svc_rdma_post_recv(newxprt);
1021 		if (ret) {
1022 			dprintk("svcrdma: failure posting receive buffers\n");
1023 			goto errout;
1024 		}
1025 	}
1026 
1027 	/* Swap out the handler */
1028 	newxprt->sc_cm_id->event_handler = rdma_cma_handler;
1029 
1030 	/*
1031 	 * Arm the CQs for the SQ and RQ before accepting so we can't
1032 	 * miss the first message
1033 	 */
1034 	ib_req_notify_cq(newxprt->sc_sq_cq, IB_CQ_NEXT_COMP);
1035 	ib_req_notify_cq(newxprt->sc_rq_cq, IB_CQ_NEXT_COMP);
1036 
1037 	/* Accept Connection */
1038 	set_bit(RDMAXPRT_CONN_PENDING, &newxprt->sc_flags);
1039 	memset(&conn_param, 0, sizeof conn_param);
1040 	conn_param.responder_resources = 0;
1041 	conn_param.initiator_depth = newxprt->sc_ord;
1042 	ret = rdma_accept(newxprt->sc_cm_id, &conn_param);
1043 	if (ret) {
1044 		dprintk("svcrdma: failed to accept new connection, ret=%d\n",
1045 		       ret);
1046 		goto errout;
1047 	}
1048 
1049 	dprintk("svcrdma: new connection %p accepted with the following "
1050 		"attributes:\n"
1051 		"    local_ip        : %d.%d.%d.%d\n"
1052 		"    local_port	     : %d\n"
1053 		"    remote_ip       : %d.%d.%d.%d\n"
1054 		"    remote_port     : %d\n"
1055 		"    max_sge         : %d\n"
1056 		"    sq_depth        : %d\n"
1057 		"    max_requests    : %d\n"
1058 		"    ord             : %d\n",
1059 		newxprt,
1060 		NIPQUAD(((struct sockaddr_in *)&newxprt->sc_cm_id->
1061 			 route.addr.src_addr)->sin_addr.s_addr),
1062 		ntohs(((struct sockaddr_in *)&newxprt->sc_cm_id->
1063 		       route.addr.src_addr)->sin_port),
1064 		NIPQUAD(((struct sockaddr_in *)&newxprt->sc_cm_id->
1065 			 route.addr.dst_addr)->sin_addr.s_addr),
1066 		ntohs(((struct sockaddr_in *)&newxprt->sc_cm_id->
1067 		       route.addr.dst_addr)->sin_port),
1068 		newxprt->sc_max_sge,
1069 		newxprt->sc_sq_depth,
1070 		newxprt->sc_max_requests,
1071 		newxprt->sc_ord);
1072 
1073 	return &newxprt->sc_xprt;
1074 
1075  errout:
1076 	dprintk("svcrdma: failure accepting new connection rc=%d.\n", ret);
1077 	/* Take a reference in case the DTO handler runs */
1078 	svc_xprt_get(&newxprt->sc_xprt);
1079 	if (newxprt->sc_qp && !IS_ERR(newxprt->sc_qp))
1080 		ib_destroy_qp(newxprt->sc_qp);
1081 	rdma_destroy_id(newxprt->sc_cm_id);
1082 	/* This call to put will destroy the transport */
1083 	svc_xprt_put(&newxprt->sc_xprt);
1084 	return NULL;
1085 }
1086 
1087 static void svc_rdma_release_rqst(struct svc_rqst *rqstp)
1088 {
1089 }
1090 
1091 /*
1092  * When connected, an svc_xprt has at least two references:
1093  *
1094  * - A reference held by the cm_id between the ESTABLISHED and
1095  *   DISCONNECTED events. If the remote peer disconnected first, this
1096  *   reference could be gone.
1097  *
1098  * - A reference held by the svc_recv code that called this function
1099  *   as part of close processing.
1100  *
1101  * At a minimum one references should still be held.
1102  */
1103 static void svc_rdma_detach(struct svc_xprt *xprt)
1104 {
1105 	struct svcxprt_rdma *rdma =
1106 		container_of(xprt, struct svcxprt_rdma, sc_xprt);
1107 	dprintk("svc: svc_rdma_detach(%p)\n", xprt);
1108 
1109 	/* Disconnect and flush posted WQE */
1110 	rdma_disconnect(rdma->sc_cm_id);
1111 }
1112 
1113 static void __svc_rdma_free(struct work_struct *work)
1114 {
1115 	struct svcxprt_rdma *rdma =
1116 		container_of(work, struct svcxprt_rdma, sc_work);
1117 	dprintk("svcrdma: svc_rdma_free(%p)\n", rdma);
1118 
1119 	/* We should only be called from kref_put */
1120 	BUG_ON(atomic_read(&rdma->sc_xprt.xpt_ref.refcount) != 0);
1121 
1122 	/*
1123 	 * Destroy queued, but not processed read completions. Note
1124 	 * that this cleanup has to be done before destroying the
1125 	 * cm_id because the device ptr is needed to unmap the dma in
1126 	 * svc_rdma_put_context.
1127 	 */
1128 	while (!list_empty(&rdma->sc_read_complete_q)) {
1129 		struct svc_rdma_op_ctxt *ctxt;
1130 		ctxt = list_entry(rdma->sc_read_complete_q.next,
1131 				  struct svc_rdma_op_ctxt,
1132 				  dto_q);
1133 		list_del_init(&ctxt->dto_q);
1134 		svc_rdma_put_context(ctxt, 1);
1135 	}
1136 
1137 	/* Destroy queued, but not processed recv completions */
1138 	while (!list_empty(&rdma->sc_rq_dto_q)) {
1139 		struct svc_rdma_op_ctxt *ctxt;
1140 		ctxt = list_entry(rdma->sc_rq_dto_q.next,
1141 				  struct svc_rdma_op_ctxt,
1142 				  dto_q);
1143 		list_del_init(&ctxt->dto_q);
1144 		svc_rdma_put_context(ctxt, 1);
1145 	}
1146 
1147 	/* Warn if we leaked a resource or under-referenced */
1148 	WARN_ON(atomic_read(&rdma->sc_ctxt_used) != 0);
1149 	WARN_ON(atomic_read(&rdma->sc_dma_used) != 0);
1150 
1151 	/* De-allocate fastreg mr */
1152 	rdma_dealloc_frmr_q(rdma);
1153 
1154 	/* Destroy the QP if present (not a listener) */
1155 	if (rdma->sc_qp && !IS_ERR(rdma->sc_qp))
1156 		ib_destroy_qp(rdma->sc_qp);
1157 
1158 	if (rdma->sc_sq_cq && !IS_ERR(rdma->sc_sq_cq))
1159 		ib_destroy_cq(rdma->sc_sq_cq);
1160 
1161 	if (rdma->sc_rq_cq && !IS_ERR(rdma->sc_rq_cq))
1162 		ib_destroy_cq(rdma->sc_rq_cq);
1163 
1164 	if (rdma->sc_phys_mr && !IS_ERR(rdma->sc_phys_mr))
1165 		ib_dereg_mr(rdma->sc_phys_mr);
1166 
1167 	if (rdma->sc_pd && !IS_ERR(rdma->sc_pd))
1168 		ib_dealloc_pd(rdma->sc_pd);
1169 
1170 	/* Destroy the CM ID */
1171 	rdma_destroy_id(rdma->sc_cm_id);
1172 
1173 	kfree(rdma);
1174 }
1175 
1176 static void svc_rdma_free(struct svc_xprt *xprt)
1177 {
1178 	struct svcxprt_rdma *rdma =
1179 		container_of(xprt, struct svcxprt_rdma, sc_xprt);
1180 	INIT_WORK(&rdma->sc_work, __svc_rdma_free);
1181 	schedule_work(&rdma->sc_work);
1182 }
1183 
1184 static int svc_rdma_has_wspace(struct svc_xprt *xprt)
1185 {
1186 	struct svcxprt_rdma *rdma =
1187 		container_of(xprt, struct svcxprt_rdma, sc_xprt);
1188 
1189 	/*
1190 	 * If there are fewer SQ WR available than required to send a
1191 	 * simple response, return false.
1192 	 */
1193 	if ((rdma->sc_sq_depth - atomic_read(&rdma->sc_sq_count) < 3))
1194 		return 0;
1195 
1196 	/*
1197 	 * ...or there are already waiters on the SQ,
1198 	 * return false.
1199 	 */
1200 	if (waitqueue_active(&rdma->sc_send_wait))
1201 		return 0;
1202 
1203 	/* Otherwise return true. */
1204 	return 1;
1205 }
1206 
1207 /*
1208  * Attempt to register the kvec representing the RPC memory with the
1209  * device.
1210  *
1211  * Returns:
1212  *  NULL : The device does not support fastreg or there were no more
1213  *         fastreg mr.
1214  *  frmr : The kvec register request was successfully posted.
1215  *    <0 : An error was encountered attempting to register the kvec.
1216  */
1217 int svc_rdma_fastreg(struct svcxprt_rdma *xprt,
1218 		     struct svc_rdma_fastreg_mr *frmr)
1219 {
1220 	struct ib_send_wr fastreg_wr;
1221 	u8 key;
1222 
1223 	/* Bump the key */
1224 	key = (u8)(frmr->mr->lkey & 0x000000FF);
1225 	ib_update_fast_reg_key(frmr->mr, ++key);
1226 
1227 	/* Prepare FASTREG WR */
1228 	memset(&fastreg_wr, 0, sizeof fastreg_wr);
1229 	fastreg_wr.opcode = IB_WR_FAST_REG_MR;
1230 	fastreg_wr.send_flags = IB_SEND_SIGNALED;
1231 	fastreg_wr.wr.fast_reg.iova_start = (unsigned long)frmr->kva;
1232 	fastreg_wr.wr.fast_reg.page_list = frmr->page_list;
1233 	fastreg_wr.wr.fast_reg.page_list_len = frmr->page_list_len;
1234 	fastreg_wr.wr.fast_reg.page_shift = PAGE_SHIFT;
1235 	fastreg_wr.wr.fast_reg.length = frmr->map_len;
1236 	fastreg_wr.wr.fast_reg.access_flags = frmr->access_flags;
1237 	fastreg_wr.wr.fast_reg.rkey = frmr->mr->lkey;
1238 	return svc_rdma_send(xprt, &fastreg_wr);
1239 }
1240 
1241 int svc_rdma_send(struct svcxprt_rdma *xprt, struct ib_send_wr *wr)
1242 {
1243 	struct ib_send_wr *bad_wr, *n_wr;
1244 	int wr_count;
1245 	int i;
1246 	int ret;
1247 
1248 	if (test_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags))
1249 		return -ENOTCONN;
1250 
1251 	BUG_ON(wr->send_flags != IB_SEND_SIGNALED);
1252 	wr_count = 1;
1253 	for (n_wr = wr->next; n_wr; n_wr = n_wr->next)
1254 		wr_count++;
1255 
1256 	/* If the SQ is full, wait until an SQ entry is available */
1257 	while (1) {
1258 		spin_lock_bh(&xprt->sc_lock);
1259 		if (xprt->sc_sq_depth < atomic_read(&xprt->sc_sq_count) + wr_count) {
1260 			spin_unlock_bh(&xprt->sc_lock);
1261 			atomic_inc(&rdma_stat_sq_starve);
1262 
1263 			/* See if we can opportunistically reap SQ WR to make room */
1264 			sq_cq_reap(xprt);
1265 
1266 			/* Wait until SQ WR available if SQ still full */
1267 			wait_event(xprt->sc_send_wait,
1268 				   atomic_read(&xprt->sc_sq_count) <
1269 				   xprt->sc_sq_depth);
1270 			if (test_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags))
1271 				return 0;
1272 			continue;
1273 		}
1274 		/* Take a transport ref for each WR posted */
1275 		for (i = 0; i < wr_count; i++)
1276 			svc_xprt_get(&xprt->sc_xprt);
1277 
1278 		/* Bump used SQ WR count and post */
1279 		atomic_add(wr_count, &xprt->sc_sq_count);
1280 		ret = ib_post_send(xprt->sc_qp, wr, &bad_wr);
1281 		if (ret) {
1282 			set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
1283 			atomic_sub(wr_count, &xprt->sc_sq_count);
1284 			for (i = 0; i < wr_count; i ++)
1285 				svc_xprt_put(&xprt->sc_xprt);
1286 			dprintk("svcrdma: failed to post SQ WR rc=%d, "
1287 			       "sc_sq_count=%d, sc_sq_depth=%d\n",
1288 			       ret, atomic_read(&xprt->sc_sq_count),
1289 			       xprt->sc_sq_depth);
1290 		}
1291 		spin_unlock_bh(&xprt->sc_lock);
1292 		if (ret)
1293 			wake_up(&xprt->sc_send_wait);
1294 		break;
1295 	}
1296 	return ret;
1297 }
1298 
1299 void svc_rdma_send_error(struct svcxprt_rdma *xprt, struct rpcrdma_msg *rmsgp,
1300 			 enum rpcrdma_errcode err)
1301 {
1302 	struct ib_send_wr err_wr;
1303 	struct ib_sge sge;
1304 	struct page *p;
1305 	struct svc_rdma_op_ctxt *ctxt;
1306 	u32 *va;
1307 	int length;
1308 	int ret;
1309 
1310 	p = svc_rdma_get_page();
1311 	va = page_address(p);
1312 
1313 	/* XDR encode error */
1314 	length = svc_rdma_xdr_encode_error(xprt, rmsgp, err, va);
1315 
1316 	/* Prepare SGE for local address */
1317 	sge.addr = ib_dma_map_page(xprt->sc_cm_id->device,
1318 				   p, 0, PAGE_SIZE, DMA_FROM_DEVICE);
1319 	if (ib_dma_mapping_error(xprt->sc_cm_id->device, sge.addr)) {
1320 		put_page(p);
1321 		return;
1322 	}
1323 	atomic_inc(&xprt->sc_dma_used);
1324 	sge.lkey = xprt->sc_dma_lkey;
1325 	sge.length = length;
1326 
1327 	ctxt = svc_rdma_get_context(xprt);
1328 	ctxt->count = 1;
1329 	ctxt->pages[0] = p;
1330 
1331 	/* Prepare SEND WR */
1332 	memset(&err_wr, 0, sizeof err_wr);
1333 	ctxt->wr_op = IB_WR_SEND;
1334 	err_wr.wr_id = (unsigned long)ctxt;
1335 	err_wr.sg_list = &sge;
1336 	err_wr.num_sge = 1;
1337 	err_wr.opcode = IB_WR_SEND;
1338 	err_wr.send_flags = IB_SEND_SIGNALED;
1339 
1340 	/* Post It */
1341 	ret = svc_rdma_send(xprt, &err_wr);
1342 	if (ret) {
1343 		dprintk("svcrdma: Error %d posting send for protocol error\n",
1344 			ret);
1345 		ib_dma_unmap_page(xprt->sc_cm_id->device,
1346 				  sge.addr, PAGE_SIZE,
1347 				  DMA_FROM_DEVICE);
1348 		svc_rdma_put_context(ctxt, 1);
1349 	}
1350 }
1351