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 struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *xprt)
157 {
158 	struct svc_rdma_op_ctxt *ctxt;
159 
160 	ctxt = kmem_cache_alloc(svc_rdma_ctxt_cachep,
161 				GFP_KERNEL | __GFP_NOFAIL);
162 	ctxt->xprt = xprt;
163 	INIT_LIST_HEAD(&ctxt->dto_q);
164 	ctxt->count = 0;
165 	ctxt->frmr = NULL;
166 	atomic_inc(&xprt->sc_ctxt_used);
167 	return ctxt;
168 }
169 
170 void svc_rdma_unmap_dma(struct svc_rdma_op_ctxt *ctxt)
171 {
172 	struct svcxprt_rdma *xprt = ctxt->xprt;
173 	int i;
174 	for (i = 0; i < ctxt->count && ctxt->sge[i].length; i++) {
175 		/*
176 		 * Unmap the DMA addr in the SGE if the lkey matches
177 		 * the sc_dma_lkey, otherwise, ignore it since it is
178 		 * an FRMR lkey and will be unmapped later when the
179 		 * last WR that uses it completes.
180 		 */
181 		if (ctxt->sge[i].lkey == xprt->sc_dma_lkey) {
182 			atomic_dec(&xprt->sc_dma_used);
183 			ib_dma_unmap_page(xprt->sc_cm_id->device,
184 					    ctxt->sge[i].addr,
185 					    ctxt->sge[i].length,
186 					    ctxt->direction);
187 		}
188 	}
189 }
190 
191 void svc_rdma_put_context(struct svc_rdma_op_ctxt *ctxt, int free_pages)
192 {
193 	struct svcxprt_rdma *xprt;
194 	int i;
195 
196 	xprt = ctxt->xprt;
197 	if (free_pages)
198 		for (i = 0; i < ctxt->count; i++)
199 			put_page(ctxt->pages[i]);
200 
201 	kmem_cache_free(svc_rdma_ctxt_cachep, ctxt);
202 	atomic_dec(&xprt->sc_ctxt_used);
203 }
204 
205 /*
206  * Temporary NFS req mappings are shared across all transport
207  * instances. These are short lived and should be bounded by the number
208  * of concurrent server threads * depth of the SQ.
209  */
210 struct svc_rdma_req_map *svc_rdma_get_req_map(void)
211 {
212 	struct svc_rdma_req_map *map;
213 	map = kmem_cache_alloc(svc_rdma_map_cachep,
214 			       GFP_KERNEL | __GFP_NOFAIL);
215 	map->count = 0;
216 	return map;
217 }
218 
219 void svc_rdma_put_req_map(struct svc_rdma_req_map *map)
220 {
221 	kmem_cache_free(svc_rdma_map_cachep, map);
222 }
223 
224 /* ib_cq event handler */
225 static void cq_event_handler(struct ib_event *event, void *context)
226 {
227 	struct svc_xprt *xprt = context;
228 	dprintk("svcrdma: received CQ event %s (%d), context=%p\n",
229 		ib_event_msg(event->event), event->event, context);
230 	set_bit(XPT_CLOSE, &xprt->xpt_flags);
231 }
232 
233 /* QP event handler */
234 static void qp_event_handler(struct ib_event *event, void *context)
235 {
236 	struct svc_xprt *xprt = context;
237 
238 	switch (event->event) {
239 	/* These are considered benign events */
240 	case IB_EVENT_PATH_MIG:
241 	case IB_EVENT_COMM_EST:
242 	case IB_EVENT_SQ_DRAINED:
243 	case IB_EVENT_QP_LAST_WQE_REACHED:
244 		dprintk("svcrdma: QP event %s (%d) received for QP=%p\n",
245 			ib_event_msg(event->event), event->event,
246 			event->element.qp);
247 		break;
248 	/* These are considered fatal events */
249 	case IB_EVENT_PATH_MIG_ERR:
250 	case IB_EVENT_QP_FATAL:
251 	case IB_EVENT_QP_REQ_ERR:
252 	case IB_EVENT_QP_ACCESS_ERR:
253 	case IB_EVENT_DEVICE_FATAL:
254 	default:
255 		dprintk("svcrdma: QP ERROR event %s (%d) received for QP=%p, "
256 			"closing transport\n",
257 			ib_event_msg(event->event), event->event,
258 			event->element.qp);
259 		set_bit(XPT_CLOSE, &xprt->xpt_flags);
260 		break;
261 	}
262 }
263 
264 /*
265  * Data Transfer Operation Tasklet
266  *
267  * Walks a list of transports with I/O pending, removing entries as
268  * they are added to the server's I/O pending list. Two bits indicate
269  * if SQ, RQ, or both have I/O pending. The dto_lock is an irqsave
270  * spinlock that serializes access to the transport list with the RQ
271  * and SQ interrupt handlers.
272  */
273 static void dto_tasklet_func(unsigned long data)
274 {
275 	struct svcxprt_rdma *xprt;
276 	unsigned long flags;
277 
278 	spin_lock_irqsave(&dto_lock, flags);
279 	while (!list_empty(&dto_xprt_q)) {
280 		xprt = list_entry(dto_xprt_q.next,
281 				  struct svcxprt_rdma, sc_dto_q);
282 		list_del_init(&xprt->sc_dto_q);
283 		spin_unlock_irqrestore(&dto_lock, flags);
284 
285 		rq_cq_reap(xprt);
286 		sq_cq_reap(xprt);
287 
288 		svc_xprt_put(&xprt->sc_xprt);
289 		spin_lock_irqsave(&dto_lock, flags);
290 	}
291 	spin_unlock_irqrestore(&dto_lock, flags);
292 }
293 
294 /*
295  * Receive Queue Completion Handler
296  *
297  * Since an RQ completion handler is called on interrupt context, we
298  * need to defer the handling of the I/O to a tasklet
299  */
300 static void rq_comp_handler(struct ib_cq *cq, void *cq_context)
301 {
302 	struct svcxprt_rdma *xprt = cq_context;
303 	unsigned long flags;
304 
305 	/* Guard against unconditional flush call for destroyed QP */
306 	if (atomic_read(&xprt->sc_xprt.xpt_ref.refcount)==0)
307 		return;
308 
309 	/*
310 	 * Set the bit regardless of whether or not it's on the list
311 	 * because it may be on the list already due to an SQ
312 	 * completion.
313 	 */
314 	set_bit(RDMAXPRT_RQ_PENDING, &xprt->sc_flags);
315 
316 	/*
317 	 * If this transport is not already on the DTO transport queue,
318 	 * add it
319 	 */
320 	spin_lock_irqsave(&dto_lock, flags);
321 	if (list_empty(&xprt->sc_dto_q)) {
322 		svc_xprt_get(&xprt->sc_xprt);
323 		list_add_tail(&xprt->sc_dto_q, &dto_xprt_q);
324 	}
325 	spin_unlock_irqrestore(&dto_lock, flags);
326 
327 	/* Tasklet does all the work to avoid irqsave locks. */
328 	tasklet_schedule(&dto_tasklet);
329 }
330 
331 /*
332  * rq_cq_reap - Process the RQ CQ.
333  *
334  * Take all completing WC off the CQE and enqueue the associated DTO
335  * context on the dto_q for the transport.
336  *
337  * Note that caller must hold a transport reference.
338  */
339 static void rq_cq_reap(struct svcxprt_rdma *xprt)
340 {
341 	int ret;
342 	struct ib_wc wc;
343 	struct svc_rdma_op_ctxt *ctxt = NULL;
344 
345 	if (!test_and_clear_bit(RDMAXPRT_RQ_PENDING, &xprt->sc_flags))
346 		return;
347 
348 	ib_req_notify_cq(xprt->sc_rq_cq, IB_CQ_NEXT_COMP);
349 	atomic_inc(&rdma_stat_rq_poll);
350 
351 	while ((ret = ib_poll_cq(xprt->sc_rq_cq, 1, &wc)) > 0) {
352 		ctxt = (struct svc_rdma_op_ctxt *)(unsigned long)wc.wr_id;
353 		ctxt->wc_status = wc.status;
354 		ctxt->byte_len = wc.byte_len;
355 		svc_rdma_unmap_dma(ctxt);
356 		if (wc.status != IB_WC_SUCCESS) {
357 			/* Close the transport */
358 			dprintk("svcrdma: transport closing putting ctxt %p\n", ctxt);
359 			set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
360 			svc_rdma_put_context(ctxt, 1);
361 			svc_xprt_put(&xprt->sc_xprt);
362 			continue;
363 		}
364 		spin_lock_bh(&xprt->sc_rq_dto_lock);
365 		list_add_tail(&ctxt->dto_q, &xprt->sc_rq_dto_q);
366 		spin_unlock_bh(&xprt->sc_rq_dto_lock);
367 		svc_xprt_put(&xprt->sc_xprt);
368 	}
369 
370 	if (ctxt)
371 		atomic_inc(&rdma_stat_rq_prod);
372 
373 	set_bit(XPT_DATA, &xprt->sc_xprt.xpt_flags);
374 	/*
375 	 * If data arrived before established event,
376 	 * don't enqueue. This defers RPC I/O until the
377 	 * RDMA connection is complete.
378 	 */
379 	if (!test_bit(RDMAXPRT_CONN_PENDING, &xprt->sc_flags))
380 		svc_xprt_enqueue(&xprt->sc_xprt);
381 }
382 
383 /*
384  * Process a completion context
385  */
386 static void process_context(struct svcxprt_rdma *xprt,
387 			    struct svc_rdma_op_ctxt *ctxt)
388 {
389 	svc_rdma_unmap_dma(ctxt);
390 
391 	switch (ctxt->wr_op) {
392 	case IB_WR_SEND:
393 		if (ctxt->frmr)
394 			pr_err("svcrdma: SEND: ctxt->frmr != NULL\n");
395 		svc_rdma_put_context(ctxt, 1);
396 		break;
397 
398 	case IB_WR_RDMA_WRITE:
399 		if (ctxt->frmr)
400 			pr_err("svcrdma: WRITE: ctxt->frmr != NULL\n");
401 		svc_rdma_put_context(ctxt, 0);
402 		break;
403 
404 	case IB_WR_RDMA_READ:
405 	case IB_WR_RDMA_READ_WITH_INV:
406 		svc_rdma_put_frmr(xprt, ctxt->frmr);
407 		if (test_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags)) {
408 			struct svc_rdma_op_ctxt *read_hdr = ctxt->read_hdr;
409 			if (read_hdr) {
410 				spin_lock_bh(&xprt->sc_rq_dto_lock);
411 				set_bit(XPT_DATA, &xprt->sc_xprt.xpt_flags);
412 				list_add_tail(&read_hdr->dto_q,
413 					      &xprt->sc_read_complete_q);
414 				spin_unlock_bh(&xprt->sc_rq_dto_lock);
415 			} else {
416 				pr_err("svcrdma: ctxt->read_hdr == NULL\n");
417 			}
418 			svc_xprt_enqueue(&xprt->sc_xprt);
419 		}
420 		svc_rdma_put_context(ctxt, 0);
421 		break;
422 
423 	default:
424 		printk(KERN_ERR "svcrdma: unexpected completion type, "
425 		       "opcode=%d\n",
426 		       ctxt->wr_op);
427 		break;
428 	}
429 }
430 
431 /*
432  * Send Queue Completion Handler - potentially called on interrupt context.
433  *
434  * Note that caller must hold a transport reference.
435  */
436 static void sq_cq_reap(struct svcxprt_rdma *xprt)
437 {
438 	struct svc_rdma_op_ctxt *ctxt = NULL;
439 	struct ib_wc wc_a[6];
440 	struct ib_wc *wc;
441 	struct ib_cq *cq = xprt->sc_sq_cq;
442 	int ret;
443 
444 	memset(wc_a, 0, sizeof(wc_a));
445 
446 	if (!test_and_clear_bit(RDMAXPRT_SQ_PENDING, &xprt->sc_flags))
447 		return;
448 
449 	ib_req_notify_cq(xprt->sc_sq_cq, IB_CQ_NEXT_COMP);
450 	atomic_inc(&rdma_stat_sq_poll);
451 	while ((ret = ib_poll_cq(cq, ARRAY_SIZE(wc_a), wc_a)) > 0) {
452 		int i;
453 
454 		for (i = 0; i < ret; i++) {
455 			wc = &wc_a[i];
456 			if (wc->status != IB_WC_SUCCESS) {
457 				dprintk("svcrdma: sq wc err status %s (%d)\n",
458 					ib_wc_status_msg(wc->status),
459 					wc->status);
460 
461 				/* Close the transport */
462 				set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
463 			}
464 
465 			/* Decrement used SQ WR count */
466 			atomic_dec(&xprt->sc_sq_count);
467 			wake_up(&xprt->sc_send_wait);
468 
469 			ctxt = (struct svc_rdma_op_ctxt *)
470 				(unsigned long)wc->wr_id;
471 			if (ctxt)
472 				process_context(xprt, ctxt);
473 
474 			svc_xprt_put(&xprt->sc_xprt);
475 		}
476 	}
477 
478 	if (ctxt)
479 		atomic_inc(&rdma_stat_sq_prod);
480 }
481 
482 static void sq_comp_handler(struct ib_cq *cq, void *cq_context)
483 {
484 	struct svcxprt_rdma *xprt = cq_context;
485 	unsigned long flags;
486 
487 	/* Guard against unconditional flush call for destroyed QP */
488 	if (atomic_read(&xprt->sc_xprt.xpt_ref.refcount)==0)
489 		return;
490 
491 	/*
492 	 * Set the bit regardless of whether or not it's on the list
493 	 * because it may be on the list already due to an RQ
494 	 * completion.
495 	 */
496 	set_bit(RDMAXPRT_SQ_PENDING, &xprt->sc_flags);
497 
498 	/*
499 	 * If this transport is not already on the DTO transport queue,
500 	 * add it
501 	 */
502 	spin_lock_irqsave(&dto_lock, flags);
503 	if (list_empty(&xprt->sc_dto_q)) {
504 		svc_xprt_get(&xprt->sc_xprt);
505 		list_add_tail(&xprt->sc_dto_q, &dto_xprt_q);
506 	}
507 	spin_unlock_irqrestore(&dto_lock, flags);
508 
509 	/* Tasklet does all the work to avoid irqsave locks. */
510 	tasklet_schedule(&dto_tasklet);
511 }
512 
513 static struct svcxprt_rdma *rdma_create_xprt(struct svc_serv *serv,
514 					     int listener)
515 {
516 	struct svcxprt_rdma *cma_xprt = kzalloc(sizeof *cma_xprt, GFP_KERNEL);
517 
518 	if (!cma_xprt)
519 		return NULL;
520 	svc_xprt_init(&init_net, &svc_rdma_class, &cma_xprt->sc_xprt, serv);
521 	INIT_LIST_HEAD(&cma_xprt->sc_accept_q);
522 	INIT_LIST_HEAD(&cma_xprt->sc_dto_q);
523 	INIT_LIST_HEAD(&cma_xprt->sc_rq_dto_q);
524 	INIT_LIST_HEAD(&cma_xprt->sc_read_complete_q);
525 	INIT_LIST_HEAD(&cma_xprt->sc_frmr_q);
526 	init_waitqueue_head(&cma_xprt->sc_send_wait);
527 
528 	spin_lock_init(&cma_xprt->sc_lock);
529 	spin_lock_init(&cma_xprt->sc_rq_dto_lock);
530 	spin_lock_init(&cma_xprt->sc_frmr_q_lock);
531 
532 	cma_xprt->sc_ord = svcrdma_ord;
533 
534 	cma_xprt->sc_max_req_size = svcrdma_max_req_size;
535 	cma_xprt->sc_max_requests = svcrdma_max_requests;
536 	cma_xprt->sc_sq_depth = svcrdma_max_requests * RPCRDMA_SQ_DEPTH_MULT;
537 	atomic_set(&cma_xprt->sc_sq_count, 0);
538 	atomic_set(&cma_xprt->sc_ctxt_used, 0);
539 
540 	if (listener)
541 		set_bit(XPT_LISTENER, &cma_xprt->sc_xprt.xpt_flags);
542 
543 	return cma_xprt;
544 }
545 
546 int svc_rdma_post_recv(struct svcxprt_rdma *xprt)
547 {
548 	struct ib_recv_wr recv_wr, *bad_recv_wr;
549 	struct svc_rdma_op_ctxt *ctxt;
550 	struct page *page;
551 	dma_addr_t pa;
552 	int sge_no;
553 	int buflen;
554 	int ret;
555 
556 	ctxt = svc_rdma_get_context(xprt);
557 	buflen = 0;
558 	ctxt->direction = DMA_FROM_DEVICE;
559 	for (sge_no = 0; buflen < xprt->sc_max_req_size; sge_no++) {
560 		if (sge_no >= xprt->sc_max_sge) {
561 			pr_err("svcrdma: Too many sges (%d)\n", sge_no);
562 			goto err_put_ctxt;
563 		}
564 		page = alloc_page(GFP_KERNEL | __GFP_NOFAIL);
565 		ctxt->pages[sge_no] = page;
566 		pa = ib_dma_map_page(xprt->sc_cm_id->device,
567 				     page, 0, PAGE_SIZE,
568 				     DMA_FROM_DEVICE);
569 		if (ib_dma_mapping_error(xprt->sc_cm_id->device, pa))
570 			goto err_put_ctxt;
571 		atomic_inc(&xprt->sc_dma_used);
572 		ctxt->sge[sge_no].addr = pa;
573 		ctxt->sge[sge_no].length = PAGE_SIZE;
574 		ctxt->sge[sge_no].lkey = xprt->sc_dma_lkey;
575 		ctxt->count = sge_no + 1;
576 		buflen += PAGE_SIZE;
577 	}
578 	recv_wr.next = NULL;
579 	recv_wr.sg_list = &ctxt->sge[0];
580 	recv_wr.num_sge = ctxt->count;
581 	recv_wr.wr_id = (u64)(unsigned long)ctxt;
582 
583 	svc_xprt_get(&xprt->sc_xprt);
584 	ret = ib_post_recv(xprt->sc_qp, &recv_wr, &bad_recv_wr);
585 	if (ret) {
586 		svc_rdma_unmap_dma(ctxt);
587 		svc_rdma_put_context(ctxt, 1);
588 		svc_xprt_put(&xprt->sc_xprt);
589 	}
590 	return ret;
591 
592  err_put_ctxt:
593 	svc_rdma_unmap_dma(ctxt);
594 	svc_rdma_put_context(ctxt, 1);
595 	return -ENOMEM;
596 }
597 
598 /*
599  * This function handles the CONNECT_REQUEST event on a listening
600  * endpoint. It is passed the cma_id for the _new_ connection. The context in
601  * this cma_id is inherited from the listening cma_id and is the svc_xprt
602  * structure for the listening endpoint.
603  *
604  * This function creates a new xprt for the new connection and enqueues it on
605  * the accept queue for the listent xprt. When the listen thread is kicked, it
606  * will call the recvfrom method on the listen xprt which will accept the new
607  * connection.
608  */
609 static void handle_connect_req(struct rdma_cm_id *new_cma_id, size_t client_ird)
610 {
611 	struct svcxprt_rdma *listen_xprt = new_cma_id->context;
612 	struct svcxprt_rdma *newxprt;
613 	struct sockaddr *sa;
614 
615 	/* Create a new transport */
616 	newxprt = rdma_create_xprt(listen_xprt->sc_xprt.xpt_server, 0);
617 	if (!newxprt) {
618 		dprintk("svcrdma: failed to create new transport\n");
619 		return;
620 	}
621 	newxprt->sc_cm_id = new_cma_id;
622 	new_cma_id->context = newxprt;
623 	dprintk("svcrdma: Creating newxprt=%p, cm_id=%p, listenxprt=%p\n",
624 		newxprt, newxprt->sc_cm_id, listen_xprt);
625 
626 	/* Save client advertised inbound read limit for use later in accept. */
627 	newxprt->sc_ord = client_ird;
628 
629 	/* Set the local and remote addresses in the transport */
630 	sa = (struct sockaddr *)&newxprt->sc_cm_id->route.addr.dst_addr;
631 	svc_xprt_set_remote(&newxprt->sc_xprt, sa, svc_addr_len(sa));
632 	sa = (struct sockaddr *)&newxprt->sc_cm_id->route.addr.src_addr;
633 	svc_xprt_set_local(&newxprt->sc_xprt, sa, svc_addr_len(sa));
634 
635 	/*
636 	 * Enqueue the new transport on the accept queue of the listening
637 	 * transport
638 	 */
639 	spin_lock_bh(&listen_xprt->sc_lock);
640 	list_add_tail(&newxprt->sc_accept_q, &listen_xprt->sc_accept_q);
641 	spin_unlock_bh(&listen_xprt->sc_lock);
642 
643 	set_bit(XPT_CONN, &listen_xprt->sc_xprt.xpt_flags);
644 	svc_xprt_enqueue(&listen_xprt->sc_xprt);
645 }
646 
647 /*
648  * Handles events generated on the listening endpoint. These events will be
649  * either be incoming connect requests or adapter removal  events.
650  */
651 static int rdma_listen_handler(struct rdma_cm_id *cma_id,
652 			       struct rdma_cm_event *event)
653 {
654 	struct svcxprt_rdma *xprt = cma_id->context;
655 	int ret = 0;
656 
657 	switch (event->event) {
658 	case RDMA_CM_EVENT_CONNECT_REQUEST:
659 		dprintk("svcrdma: Connect request on cma_id=%p, xprt = %p, "
660 			"event = %s (%d)\n", cma_id, cma_id->context,
661 			rdma_event_msg(event->event), event->event);
662 		handle_connect_req(cma_id,
663 				   event->param.conn.initiator_depth);
664 		break;
665 
666 	case RDMA_CM_EVENT_ESTABLISHED:
667 		/* Accept complete */
668 		dprintk("svcrdma: Connection completed on LISTEN xprt=%p, "
669 			"cm_id=%p\n", xprt, cma_id);
670 		break;
671 
672 	case RDMA_CM_EVENT_DEVICE_REMOVAL:
673 		dprintk("svcrdma: Device removal xprt=%p, cm_id=%p\n",
674 			xprt, cma_id);
675 		if (xprt)
676 			set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
677 		break;
678 
679 	default:
680 		dprintk("svcrdma: Unexpected event on listening endpoint %p, "
681 			"event = %s (%d)\n", cma_id,
682 			rdma_event_msg(event->event), event->event);
683 		break;
684 	}
685 
686 	return ret;
687 }
688 
689 static int rdma_cma_handler(struct rdma_cm_id *cma_id,
690 			    struct rdma_cm_event *event)
691 {
692 	struct svc_xprt *xprt = cma_id->context;
693 	struct svcxprt_rdma *rdma =
694 		container_of(xprt, struct svcxprt_rdma, sc_xprt);
695 	switch (event->event) {
696 	case RDMA_CM_EVENT_ESTABLISHED:
697 		/* Accept complete */
698 		svc_xprt_get(xprt);
699 		dprintk("svcrdma: Connection completed on DTO xprt=%p, "
700 			"cm_id=%p\n", xprt, cma_id);
701 		clear_bit(RDMAXPRT_CONN_PENDING, &rdma->sc_flags);
702 		svc_xprt_enqueue(xprt);
703 		break;
704 	case RDMA_CM_EVENT_DISCONNECTED:
705 		dprintk("svcrdma: Disconnect on DTO xprt=%p, cm_id=%p\n",
706 			xprt, cma_id);
707 		if (xprt) {
708 			set_bit(XPT_CLOSE, &xprt->xpt_flags);
709 			svc_xprt_enqueue(xprt);
710 			svc_xprt_put(xprt);
711 		}
712 		break;
713 	case RDMA_CM_EVENT_DEVICE_REMOVAL:
714 		dprintk("svcrdma: Device removal cma_id=%p, xprt = %p, "
715 			"event = %s (%d)\n", cma_id, xprt,
716 			rdma_event_msg(event->event), event->event);
717 		if (xprt) {
718 			set_bit(XPT_CLOSE, &xprt->xpt_flags);
719 			svc_xprt_enqueue(xprt);
720 			svc_xprt_put(xprt);
721 		}
722 		break;
723 	default:
724 		dprintk("svcrdma: Unexpected event on DTO endpoint %p, "
725 			"event = %s (%d)\n", cma_id,
726 			rdma_event_msg(event->event), event->event);
727 		break;
728 	}
729 	return 0;
730 }
731 
732 /*
733  * Create a listening RDMA service endpoint.
734  */
735 static struct svc_xprt *svc_rdma_create(struct svc_serv *serv,
736 					struct net *net,
737 					struct sockaddr *sa, int salen,
738 					int flags)
739 {
740 	struct rdma_cm_id *listen_id;
741 	struct svcxprt_rdma *cma_xprt;
742 	int ret;
743 
744 	dprintk("svcrdma: Creating RDMA socket\n");
745 	if (sa->sa_family != AF_INET) {
746 		dprintk("svcrdma: Address family %d is not supported.\n", sa->sa_family);
747 		return ERR_PTR(-EAFNOSUPPORT);
748 	}
749 	cma_xprt = rdma_create_xprt(serv, 1);
750 	if (!cma_xprt)
751 		return ERR_PTR(-ENOMEM);
752 
753 	listen_id = rdma_create_id(&init_net, rdma_listen_handler, cma_xprt,
754 				   RDMA_PS_TCP, IB_QPT_RC);
755 	if (IS_ERR(listen_id)) {
756 		ret = PTR_ERR(listen_id);
757 		dprintk("svcrdma: rdma_create_id failed = %d\n", ret);
758 		goto err0;
759 	}
760 
761 	ret = rdma_bind_addr(listen_id, sa);
762 	if (ret) {
763 		dprintk("svcrdma: rdma_bind_addr failed = %d\n", ret);
764 		goto err1;
765 	}
766 	cma_xprt->sc_cm_id = listen_id;
767 
768 	ret = rdma_listen(listen_id, RPCRDMA_LISTEN_BACKLOG);
769 	if (ret) {
770 		dprintk("svcrdma: rdma_listen failed = %d\n", ret);
771 		goto err1;
772 	}
773 
774 	/*
775 	 * We need to use the address from the cm_id in case the
776 	 * caller specified 0 for the port number.
777 	 */
778 	sa = (struct sockaddr *)&cma_xprt->sc_cm_id->route.addr.src_addr;
779 	svc_xprt_set_local(&cma_xprt->sc_xprt, sa, salen);
780 
781 	return &cma_xprt->sc_xprt;
782 
783  err1:
784 	rdma_destroy_id(listen_id);
785  err0:
786 	kfree(cma_xprt);
787 	return ERR_PTR(ret);
788 }
789 
790 static struct svc_rdma_fastreg_mr *rdma_alloc_frmr(struct svcxprt_rdma *xprt)
791 {
792 	struct ib_mr *mr;
793 	struct scatterlist *sg;
794 	struct svc_rdma_fastreg_mr *frmr;
795 	u32 num_sg;
796 
797 	frmr = kmalloc(sizeof(*frmr), GFP_KERNEL);
798 	if (!frmr)
799 		goto err;
800 
801 	num_sg = min_t(u32, RPCSVC_MAXPAGES, xprt->sc_frmr_pg_list_len);
802 	mr = ib_alloc_mr(xprt->sc_pd, IB_MR_TYPE_MEM_REG, num_sg);
803 	if (IS_ERR(mr))
804 		goto err_free_frmr;
805 
806 	sg = kcalloc(RPCSVC_MAXPAGES, sizeof(*sg), GFP_KERNEL);
807 	if (!sg)
808 		goto err_free_mr;
809 
810 	sg_init_table(sg, RPCSVC_MAXPAGES);
811 
812 	frmr->mr = mr;
813 	frmr->sg = sg;
814 	INIT_LIST_HEAD(&frmr->frmr_list);
815 	return frmr;
816 
817  err_free_mr:
818 	ib_dereg_mr(mr);
819  err_free_frmr:
820 	kfree(frmr);
821  err:
822 	return ERR_PTR(-ENOMEM);
823 }
824 
825 static void rdma_dealloc_frmr_q(struct svcxprt_rdma *xprt)
826 {
827 	struct svc_rdma_fastreg_mr *frmr;
828 
829 	while (!list_empty(&xprt->sc_frmr_q)) {
830 		frmr = list_entry(xprt->sc_frmr_q.next,
831 				  struct svc_rdma_fastreg_mr, frmr_list);
832 		list_del_init(&frmr->frmr_list);
833 		kfree(frmr->sg);
834 		ib_dereg_mr(frmr->mr);
835 		kfree(frmr);
836 	}
837 }
838 
839 struct svc_rdma_fastreg_mr *svc_rdma_get_frmr(struct svcxprt_rdma *rdma)
840 {
841 	struct svc_rdma_fastreg_mr *frmr = NULL;
842 
843 	spin_lock_bh(&rdma->sc_frmr_q_lock);
844 	if (!list_empty(&rdma->sc_frmr_q)) {
845 		frmr = list_entry(rdma->sc_frmr_q.next,
846 				  struct svc_rdma_fastreg_mr, frmr_list);
847 		list_del_init(&frmr->frmr_list);
848 		frmr->sg_nents = 0;
849 	}
850 	spin_unlock_bh(&rdma->sc_frmr_q_lock);
851 	if (frmr)
852 		return frmr;
853 
854 	return rdma_alloc_frmr(rdma);
855 }
856 
857 void svc_rdma_put_frmr(struct svcxprt_rdma *rdma,
858 		       struct svc_rdma_fastreg_mr *frmr)
859 {
860 	if (frmr) {
861 		ib_dma_unmap_sg(rdma->sc_cm_id->device,
862 				frmr->sg, frmr->sg_nents, frmr->direction);
863 		atomic_dec(&rdma->sc_dma_used);
864 		spin_lock_bh(&rdma->sc_frmr_q_lock);
865 		WARN_ON_ONCE(!list_empty(&frmr->frmr_list));
866 		list_add(&frmr->frmr_list, &rdma->sc_frmr_q);
867 		spin_unlock_bh(&rdma->sc_frmr_q_lock);
868 	}
869 }
870 
871 /*
872  * This is the xpo_recvfrom function for listening endpoints. Its
873  * purpose is to accept incoming connections. The CMA callback handler
874  * has already created a new transport and attached it to the new CMA
875  * ID.
876  *
877  * There is a queue of pending connections hung on the listening
878  * transport. This queue contains the new svc_xprt structure. This
879  * function takes svc_xprt structures off the accept_q and completes
880  * the connection.
881  */
882 static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
883 {
884 	struct svcxprt_rdma *listen_rdma;
885 	struct svcxprt_rdma *newxprt = NULL;
886 	struct rdma_conn_param conn_param;
887 	struct ib_cq_init_attr cq_attr = {};
888 	struct ib_qp_init_attr qp_attr;
889 	struct ib_device_attr devattr;
890 	int uninitialized_var(dma_mr_acc);
891 	int need_dma_mr = 0;
892 	int ret;
893 	int i;
894 
895 	listen_rdma = container_of(xprt, struct svcxprt_rdma, sc_xprt);
896 	clear_bit(XPT_CONN, &xprt->xpt_flags);
897 	/* Get the next entry off the accept list */
898 	spin_lock_bh(&listen_rdma->sc_lock);
899 	if (!list_empty(&listen_rdma->sc_accept_q)) {
900 		newxprt = list_entry(listen_rdma->sc_accept_q.next,
901 				     struct svcxprt_rdma, sc_accept_q);
902 		list_del_init(&newxprt->sc_accept_q);
903 	}
904 	if (!list_empty(&listen_rdma->sc_accept_q))
905 		set_bit(XPT_CONN, &listen_rdma->sc_xprt.xpt_flags);
906 	spin_unlock_bh(&listen_rdma->sc_lock);
907 	if (!newxprt)
908 		return NULL;
909 
910 	dprintk("svcrdma: newxprt from accept queue = %p, cm_id=%p\n",
911 		newxprt, newxprt->sc_cm_id);
912 
913 	ret = ib_query_device(newxprt->sc_cm_id->device, &devattr);
914 	if (ret) {
915 		dprintk("svcrdma: could not query device attributes on "
916 			"device %p, rc=%d\n", newxprt->sc_cm_id->device, ret);
917 		goto errout;
918 	}
919 
920 	/* Qualify the transport resource defaults with the
921 	 * capabilities of this particular device */
922 	newxprt->sc_max_sge = min((size_t)devattr.max_sge,
923 				  (size_t)RPCSVC_MAXPAGES);
924 	newxprt->sc_max_sge_rd = min_t(size_t, devattr.max_sge_rd,
925 				       RPCSVC_MAXPAGES);
926 	newxprt->sc_max_requests = min((size_t)devattr.max_qp_wr,
927 				   (size_t)svcrdma_max_requests);
928 	newxprt->sc_sq_depth = RPCRDMA_SQ_DEPTH_MULT * newxprt->sc_max_requests;
929 
930 	/*
931 	 * Limit ORD based on client limit, local device limit, and
932 	 * configured svcrdma limit.
933 	 */
934 	newxprt->sc_ord = min_t(size_t, devattr.max_qp_rd_atom, newxprt->sc_ord);
935 	newxprt->sc_ord = min_t(size_t,	svcrdma_ord, newxprt->sc_ord);
936 
937 	newxprt->sc_pd = ib_alloc_pd(newxprt->sc_cm_id->device);
938 	if (IS_ERR(newxprt->sc_pd)) {
939 		dprintk("svcrdma: error creating PD for connect request\n");
940 		goto errout;
941 	}
942 	cq_attr.cqe = newxprt->sc_sq_depth;
943 	newxprt->sc_sq_cq = ib_create_cq(newxprt->sc_cm_id->device,
944 					 sq_comp_handler,
945 					 cq_event_handler,
946 					 newxprt,
947 					 &cq_attr);
948 	if (IS_ERR(newxprt->sc_sq_cq)) {
949 		dprintk("svcrdma: error creating SQ CQ for connect request\n");
950 		goto errout;
951 	}
952 	cq_attr.cqe = newxprt->sc_max_requests;
953 	newxprt->sc_rq_cq = ib_create_cq(newxprt->sc_cm_id->device,
954 					 rq_comp_handler,
955 					 cq_event_handler,
956 					 newxprt,
957 					 &cq_attr);
958 	if (IS_ERR(newxprt->sc_rq_cq)) {
959 		dprintk("svcrdma: error creating RQ CQ for connect request\n");
960 		goto errout;
961 	}
962 
963 	memset(&qp_attr, 0, sizeof qp_attr);
964 	qp_attr.event_handler = qp_event_handler;
965 	qp_attr.qp_context = &newxprt->sc_xprt;
966 	qp_attr.cap.max_send_wr = newxprt->sc_sq_depth;
967 	qp_attr.cap.max_recv_wr = newxprt->sc_max_requests;
968 	qp_attr.cap.max_send_sge = newxprt->sc_max_sge;
969 	qp_attr.cap.max_recv_sge = newxprt->sc_max_sge;
970 	qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
971 	qp_attr.qp_type = IB_QPT_RC;
972 	qp_attr.send_cq = newxprt->sc_sq_cq;
973 	qp_attr.recv_cq = newxprt->sc_rq_cq;
974 	dprintk("svcrdma: newxprt->sc_cm_id=%p, newxprt->sc_pd=%p\n"
975 		"    cm_id->device=%p, sc_pd->device=%p\n"
976 		"    cap.max_send_wr = %d\n"
977 		"    cap.max_recv_wr = %d\n"
978 		"    cap.max_send_sge = %d\n"
979 		"    cap.max_recv_sge = %d\n",
980 		newxprt->sc_cm_id, newxprt->sc_pd,
981 		newxprt->sc_cm_id->device, newxprt->sc_pd->device,
982 		qp_attr.cap.max_send_wr,
983 		qp_attr.cap.max_recv_wr,
984 		qp_attr.cap.max_send_sge,
985 		qp_attr.cap.max_recv_sge);
986 
987 	ret = rdma_create_qp(newxprt->sc_cm_id, newxprt->sc_pd, &qp_attr);
988 	if (ret) {
989 		dprintk("svcrdma: failed to create QP, ret=%d\n", ret);
990 		goto errout;
991 	}
992 	newxprt->sc_qp = newxprt->sc_cm_id->qp;
993 
994 	/*
995 	 * Use the most secure set of MR resources based on the
996 	 * transport type and available memory management features in
997 	 * the device. Here's the table implemented below:
998 	 *
999 	 *		Fast	Global	DMA	Remote WR
1000 	 *		Reg	LKEY	MR	Access
1001 	 *		Sup'd	Sup'd	Needed	Needed
1002 	 *
1003 	 * IWARP	N	N	Y	Y
1004 	 *		N	Y	Y	Y
1005 	 *		Y	N	Y	N
1006 	 *		Y	Y	N	-
1007 	 *
1008 	 * IB		N	N	Y	N
1009 	 *		N	Y	N	-
1010 	 *		Y	N	Y	N
1011 	 *		Y	Y	N	-
1012 	 *
1013 	 * NB:	iWARP requires remote write access for the data sink
1014 	 *	of an RDMA_READ. IB does not.
1015 	 */
1016 	newxprt->sc_reader = rdma_read_chunk_lcl;
1017 	if (devattr.device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS) {
1018 		newxprt->sc_frmr_pg_list_len =
1019 			devattr.max_fast_reg_page_list_len;
1020 		newxprt->sc_dev_caps |= SVCRDMA_DEVCAP_FAST_REG;
1021 		newxprt->sc_reader = rdma_read_chunk_frmr;
1022 	}
1023 
1024 	/*
1025 	 * Determine if a DMA MR is required and if so, what privs are required
1026 	 */
1027 	if (!rdma_protocol_iwarp(newxprt->sc_cm_id->device,
1028 				 newxprt->sc_cm_id->port_num) &&
1029 	    !rdma_ib_or_roce(newxprt->sc_cm_id->device,
1030 			     newxprt->sc_cm_id->port_num))
1031 		goto errout;
1032 
1033 	if (!(newxprt->sc_dev_caps & SVCRDMA_DEVCAP_FAST_REG) ||
1034 	    !(devattr.device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY)) {
1035 		need_dma_mr = 1;
1036 		dma_mr_acc = IB_ACCESS_LOCAL_WRITE;
1037 		if (rdma_protocol_iwarp(newxprt->sc_cm_id->device,
1038 					newxprt->sc_cm_id->port_num) &&
1039 		    !(newxprt->sc_dev_caps & SVCRDMA_DEVCAP_FAST_REG))
1040 			dma_mr_acc |= IB_ACCESS_REMOTE_WRITE;
1041 	}
1042 
1043 	if (rdma_protocol_iwarp(newxprt->sc_cm_id->device,
1044 				newxprt->sc_cm_id->port_num))
1045 		newxprt->sc_dev_caps |= SVCRDMA_DEVCAP_READ_W_INV;
1046 
1047 	/* Create the DMA MR if needed, otherwise, use the DMA LKEY */
1048 	if (need_dma_mr) {
1049 		/* Register all of physical memory */
1050 		newxprt->sc_phys_mr =
1051 			ib_get_dma_mr(newxprt->sc_pd, dma_mr_acc);
1052 		if (IS_ERR(newxprt->sc_phys_mr)) {
1053 			dprintk("svcrdma: Failed to create DMA MR ret=%d\n",
1054 				ret);
1055 			goto errout;
1056 		}
1057 		newxprt->sc_dma_lkey = newxprt->sc_phys_mr->lkey;
1058 	} else
1059 		newxprt->sc_dma_lkey =
1060 			newxprt->sc_cm_id->device->local_dma_lkey;
1061 
1062 	/* Post receive buffers */
1063 	for (i = 0; i < newxprt->sc_max_requests; i++) {
1064 		ret = svc_rdma_post_recv(newxprt);
1065 		if (ret) {
1066 			dprintk("svcrdma: failure posting receive buffers\n");
1067 			goto errout;
1068 		}
1069 	}
1070 
1071 	/* Swap out the handler */
1072 	newxprt->sc_cm_id->event_handler = rdma_cma_handler;
1073 
1074 	/*
1075 	 * Arm the CQs for the SQ and RQ before accepting so we can't
1076 	 * miss the first message
1077 	 */
1078 	ib_req_notify_cq(newxprt->sc_sq_cq, IB_CQ_NEXT_COMP);
1079 	ib_req_notify_cq(newxprt->sc_rq_cq, IB_CQ_NEXT_COMP);
1080 
1081 	/* Accept Connection */
1082 	set_bit(RDMAXPRT_CONN_PENDING, &newxprt->sc_flags);
1083 	memset(&conn_param, 0, sizeof conn_param);
1084 	conn_param.responder_resources = 0;
1085 	conn_param.initiator_depth = newxprt->sc_ord;
1086 	ret = rdma_accept(newxprt->sc_cm_id, &conn_param);
1087 	if (ret) {
1088 		dprintk("svcrdma: failed to accept new connection, ret=%d\n",
1089 		       ret);
1090 		goto errout;
1091 	}
1092 
1093 	dprintk("svcrdma: new connection %p accepted with the following "
1094 		"attributes:\n"
1095 		"    local_ip        : %pI4\n"
1096 		"    local_port	     : %d\n"
1097 		"    remote_ip       : %pI4\n"
1098 		"    remote_port     : %d\n"
1099 		"    max_sge         : %d\n"
1100 		"    max_sge_rd      : %d\n"
1101 		"    sq_depth        : %d\n"
1102 		"    max_requests    : %d\n"
1103 		"    ord             : %d\n",
1104 		newxprt,
1105 		&((struct sockaddr_in *)&newxprt->sc_cm_id->
1106 			 route.addr.src_addr)->sin_addr.s_addr,
1107 		ntohs(((struct sockaddr_in *)&newxprt->sc_cm_id->
1108 		       route.addr.src_addr)->sin_port),
1109 		&((struct sockaddr_in *)&newxprt->sc_cm_id->
1110 			 route.addr.dst_addr)->sin_addr.s_addr,
1111 		ntohs(((struct sockaddr_in *)&newxprt->sc_cm_id->
1112 		       route.addr.dst_addr)->sin_port),
1113 		newxprt->sc_max_sge,
1114 		newxprt->sc_max_sge_rd,
1115 		newxprt->sc_sq_depth,
1116 		newxprt->sc_max_requests,
1117 		newxprt->sc_ord);
1118 
1119 	return &newxprt->sc_xprt;
1120 
1121  errout:
1122 	dprintk("svcrdma: failure accepting new connection rc=%d.\n", ret);
1123 	/* Take a reference in case the DTO handler runs */
1124 	svc_xprt_get(&newxprt->sc_xprt);
1125 	if (newxprt->sc_qp && !IS_ERR(newxprt->sc_qp))
1126 		ib_destroy_qp(newxprt->sc_qp);
1127 	rdma_destroy_id(newxprt->sc_cm_id);
1128 	/* This call to put will destroy the transport */
1129 	svc_xprt_put(&newxprt->sc_xprt);
1130 	return NULL;
1131 }
1132 
1133 static void svc_rdma_release_rqst(struct svc_rqst *rqstp)
1134 {
1135 }
1136 
1137 /*
1138  * When connected, an svc_xprt has at least two references:
1139  *
1140  * - A reference held by the cm_id between the ESTABLISHED and
1141  *   DISCONNECTED events. If the remote peer disconnected first, this
1142  *   reference could be gone.
1143  *
1144  * - A reference held by the svc_recv code that called this function
1145  *   as part of close processing.
1146  *
1147  * At a minimum one references should still be held.
1148  */
1149 static void svc_rdma_detach(struct svc_xprt *xprt)
1150 {
1151 	struct svcxprt_rdma *rdma =
1152 		container_of(xprt, struct svcxprt_rdma, sc_xprt);
1153 	dprintk("svc: svc_rdma_detach(%p)\n", xprt);
1154 
1155 	/* Disconnect and flush posted WQE */
1156 	rdma_disconnect(rdma->sc_cm_id);
1157 }
1158 
1159 static void __svc_rdma_free(struct work_struct *work)
1160 {
1161 	struct svcxprt_rdma *rdma =
1162 		container_of(work, struct svcxprt_rdma, sc_work);
1163 	dprintk("svcrdma: svc_rdma_free(%p)\n", rdma);
1164 
1165 	/* We should only be called from kref_put */
1166 	if (atomic_read(&rdma->sc_xprt.xpt_ref.refcount) != 0)
1167 		pr_err("svcrdma: sc_xprt still in use? (%d)\n",
1168 		       atomic_read(&rdma->sc_xprt.xpt_ref.refcount));
1169 
1170 	/*
1171 	 * Destroy queued, but not processed read completions. Note
1172 	 * that this cleanup has to be done before destroying the
1173 	 * cm_id because the device ptr is needed to unmap the dma in
1174 	 * svc_rdma_put_context.
1175 	 */
1176 	while (!list_empty(&rdma->sc_read_complete_q)) {
1177 		struct svc_rdma_op_ctxt *ctxt;
1178 		ctxt = list_entry(rdma->sc_read_complete_q.next,
1179 				  struct svc_rdma_op_ctxt,
1180 				  dto_q);
1181 		list_del_init(&ctxt->dto_q);
1182 		svc_rdma_put_context(ctxt, 1);
1183 	}
1184 
1185 	/* Destroy queued, but not processed recv completions */
1186 	while (!list_empty(&rdma->sc_rq_dto_q)) {
1187 		struct svc_rdma_op_ctxt *ctxt;
1188 		ctxt = list_entry(rdma->sc_rq_dto_q.next,
1189 				  struct svc_rdma_op_ctxt,
1190 				  dto_q);
1191 		list_del_init(&ctxt->dto_q);
1192 		svc_rdma_put_context(ctxt, 1);
1193 	}
1194 
1195 	/* Warn if we leaked a resource or under-referenced */
1196 	if (atomic_read(&rdma->sc_ctxt_used) != 0)
1197 		pr_err("svcrdma: ctxt still in use? (%d)\n",
1198 		       atomic_read(&rdma->sc_ctxt_used));
1199 	if (atomic_read(&rdma->sc_dma_used) != 0)
1200 		pr_err("svcrdma: dma still in use? (%d)\n",
1201 		       atomic_read(&rdma->sc_dma_used));
1202 
1203 	/* De-allocate fastreg mr */
1204 	rdma_dealloc_frmr_q(rdma);
1205 
1206 	/* Destroy the QP if present (not a listener) */
1207 	if (rdma->sc_qp && !IS_ERR(rdma->sc_qp))
1208 		ib_destroy_qp(rdma->sc_qp);
1209 
1210 	if (rdma->sc_sq_cq && !IS_ERR(rdma->sc_sq_cq))
1211 		ib_destroy_cq(rdma->sc_sq_cq);
1212 
1213 	if (rdma->sc_rq_cq && !IS_ERR(rdma->sc_rq_cq))
1214 		ib_destroy_cq(rdma->sc_rq_cq);
1215 
1216 	if (rdma->sc_phys_mr && !IS_ERR(rdma->sc_phys_mr))
1217 		ib_dereg_mr(rdma->sc_phys_mr);
1218 
1219 	if (rdma->sc_pd && !IS_ERR(rdma->sc_pd))
1220 		ib_dealloc_pd(rdma->sc_pd);
1221 
1222 	/* Destroy the CM ID */
1223 	rdma_destroy_id(rdma->sc_cm_id);
1224 
1225 	kfree(rdma);
1226 }
1227 
1228 static void svc_rdma_free(struct svc_xprt *xprt)
1229 {
1230 	struct svcxprt_rdma *rdma =
1231 		container_of(xprt, struct svcxprt_rdma, sc_xprt);
1232 	INIT_WORK(&rdma->sc_work, __svc_rdma_free);
1233 	queue_work(svc_rdma_wq, &rdma->sc_work);
1234 }
1235 
1236 static int svc_rdma_has_wspace(struct svc_xprt *xprt)
1237 {
1238 	struct svcxprt_rdma *rdma =
1239 		container_of(xprt, struct svcxprt_rdma, sc_xprt);
1240 
1241 	/*
1242 	 * If there are already waiters on the SQ,
1243 	 * return false.
1244 	 */
1245 	if (waitqueue_active(&rdma->sc_send_wait))
1246 		return 0;
1247 
1248 	/* Otherwise return true. */
1249 	return 1;
1250 }
1251 
1252 static int svc_rdma_secure_port(struct svc_rqst *rqstp)
1253 {
1254 	return 1;
1255 }
1256 
1257 int svc_rdma_send(struct svcxprt_rdma *xprt, struct ib_send_wr *wr)
1258 {
1259 	struct ib_send_wr *bad_wr, *n_wr;
1260 	int wr_count;
1261 	int i;
1262 	int ret;
1263 
1264 	if (test_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags))
1265 		return -ENOTCONN;
1266 
1267 	wr_count = 1;
1268 	for (n_wr = wr->next; n_wr; n_wr = n_wr->next)
1269 		wr_count++;
1270 
1271 	/* If the SQ is full, wait until an SQ entry is available */
1272 	while (1) {
1273 		spin_lock_bh(&xprt->sc_lock);
1274 		if (xprt->sc_sq_depth < atomic_read(&xprt->sc_sq_count) + wr_count) {
1275 			spin_unlock_bh(&xprt->sc_lock);
1276 			atomic_inc(&rdma_stat_sq_starve);
1277 
1278 			/* See if we can opportunistically reap SQ WR to make room */
1279 			sq_cq_reap(xprt);
1280 
1281 			/* Wait until SQ WR available if SQ still full */
1282 			wait_event(xprt->sc_send_wait,
1283 				   atomic_read(&xprt->sc_sq_count) <
1284 				   xprt->sc_sq_depth);
1285 			if (test_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags))
1286 				return -ENOTCONN;
1287 			continue;
1288 		}
1289 		/* Take a transport ref for each WR posted */
1290 		for (i = 0; i < wr_count; i++)
1291 			svc_xprt_get(&xprt->sc_xprt);
1292 
1293 		/* Bump used SQ WR count and post */
1294 		atomic_add(wr_count, &xprt->sc_sq_count);
1295 		ret = ib_post_send(xprt->sc_qp, wr, &bad_wr);
1296 		if (ret) {
1297 			set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
1298 			atomic_sub(wr_count, &xprt->sc_sq_count);
1299 			for (i = 0; i < wr_count; i ++)
1300 				svc_xprt_put(&xprt->sc_xprt);
1301 			dprintk("svcrdma: failed to post SQ WR rc=%d, "
1302 			       "sc_sq_count=%d, sc_sq_depth=%d\n",
1303 			       ret, atomic_read(&xprt->sc_sq_count),
1304 			       xprt->sc_sq_depth);
1305 		}
1306 		spin_unlock_bh(&xprt->sc_lock);
1307 		if (ret)
1308 			wake_up(&xprt->sc_send_wait);
1309 		break;
1310 	}
1311 	return ret;
1312 }
1313 
1314 void svc_rdma_send_error(struct svcxprt_rdma *xprt, struct rpcrdma_msg *rmsgp,
1315 			 enum rpcrdma_errcode err)
1316 {
1317 	struct ib_send_wr err_wr;
1318 	struct page *p;
1319 	struct svc_rdma_op_ctxt *ctxt;
1320 	__be32 *va;
1321 	int length;
1322 	int ret;
1323 
1324 	p = alloc_page(GFP_KERNEL | __GFP_NOFAIL);
1325 	va = page_address(p);
1326 
1327 	/* XDR encode error */
1328 	length = svc_rdma_xdr_encode_error(xprt, rmsgp, err, va);
1329 
1330 	ctxt = svc_rdma_get_context(xprt);
1331 	ctxt->direction = DMA_FROM_DEVICE;
1332 	ctxt->count = 1;
1333 	ctxt->pages[0] = p;
1334 
1335 	/* Prepare SGE for local address */
1336 	ctxt->sge[0].addr = ib_dma_map_page(xprt->sc_cm_id->device,
1337 					    p, 0, length, DMA_FROM_DEVICE);
1338 	if (ib_dma_mapping_error(xprt->sc_cm_id->device, ctxt->sge[0].addr)) {
1339 		put_page(p);
1340 		svc_rdma_put_context(ctxt, 1);
1341 		return;
1342 	}
1343 	atomic_inc(&xprt->sc_dma_used);
1344 	ctxt->sge[0].lkey = xprt->sc_dma_lkey;
1345 	ctxt->sge[0].length = length;
1346 
1347 	/* Prepare SEND WR */
1348 	memset(&err_wr, 0, sizeof err_wr);
1349 	ctxt->wr_op = IB_WR_SEND;
1350 	err_wr.wr_id = (unsigned long)ctxt;
1351 	err_wr.sg_list = ctxt->sge;
1352 	err_wr.num_sge = 1;
1353 	err_wr.opcode = IB_WR_SEND;
1354 	err_wr.send_flags = IB_SEND_SIGNALED;
1355 
1356 	/* Post It */
1357 	ret = svc_rdma_send(xprt, &err_wr);
1358 	if (ret) {
1359 		dprintk("svcrdma: Error %d posting send for protocol error\n",
1360 			ret);
1361 		svc_rdma_unmap_dma(ctxt);
1362 		svc_rdma_put_context(ctxt, 1);
1363 	}
1364 }
1365