xref: /linux/net/sunrpc/xprtrdma/verbs.c (revision 93df8a1ed6231727c5db94a80b1a6bd5ee67cec3)
1 /*
2  * Copyright (c) 2003-2007 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 
40 /*
41  * verbs.c
42  *
43  * Encapsulates the major functions managing:
44  *  o adapters
45  *  o endpoints
46  *  o connections
47  *  o buffer memory
48  */
49 
50 #include <linux/interrupt.h>
51 #include <linux/slab.h>
52 #include <linux/prefetch.h>
53 #include <linux/sunrpc/addr.h>
54 #include <asm/bitops.h>
55 
56 #include "xprt_rdma.h"
57 
58 /*
59  * Globals/Macros
60  */
61 
62 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
63 # define RPCDBG_FACILITY	RPCDBG_TRANS
64 #endif
65 
66 /*
67  * internal functions
68  */
69 
70 /*
71  * handle replies in tasklet context, using a single, global list
72  * rdma tasklet function -- just turn around and call the func
73  * for all replies on the list
74  */
75 
76 static DEFINE_SPINLOCK(rpcrdma_tk_lock_g);
77 static LIST_HEAD(rpcrdma_tasklets_g);
78 
79 static void
80 rpcrdma_run_tasklet(unsigned long data)
81 {
82 	struct rpcrdma_rep *rep;
83 	unsigned long flags;
84 
85 	data = data;
86 	spin_lock_irqsave(&rpcrdma_tk_lock_g, flags);
87 	while (!list_empty(&rpcrdma_tasklets_g)) {
88 		rep = list_entry(rpcrdma_tasklets_g.next,
89 				 struct rpcrdma_rep, rr_list);
90 		list_del(&rep->rr_list);
91 		spin_unlock_irqrestore(&rpcrdma_tk_lock_g, flags);
92 
93 		rpcrdma_reply_handler(rep);
94 
95 		spin_lock_irqsave(&rpcrdma_tk_lock_g, flags);
96 	}
97 	spin_unlock_irqrestore(&rpcrdma_tk_lock_g, flags);
98 }
99 
100 static DECLARE_TASKLET(rpcrdma_tasklet_g, rpcrdma_run_tasklet, 0UL);
101 
102 static void
103 rpcrdma_schedule_tasklet(struct list_head *sched_list)
104 {
105 	unsigned long flags;
106 
107 	spin_lock_irqsave(&rpcrdma_tk_lock_g, flags);
108 	list_splice_tail(sched_list, &rpcrdma_tasklets_g);
109 	spin_unlock_irqrestore(&rpcrdma_tk_lock_g, flags);
110 	tasklet_schedule(&rpcrdma_tasklet_g);
111 }
112 
113 static void
114 rpcrdma_qp_async_error_upcall(struct ib_event *event, void *context)
115 {
116 	struct rpcrdma_ep *ep = context;
117 
118 	pr_err("RPC:       %s: %s on device %s ep %p\n",
119 	       __func__, ib_event_msg(event->event),
120 		event->device->name, context);
121 	if (ep->rep_connected == 1) {
122 		ep->rep_connected = -EIO;
123 		rpcrdma_conn_func(ep);
124 		wake_up_all(&ep->rep_connect_wait);
125 	}
126 }
127 
128 static void
129 rpcrdma_cq_async_error_upcall(struct ib_event *event, void *context)
130 {
131 	struct rpcrdma_ep *ep = context;
132 
133 	pr_err("RPC:       %s: %s on device %s ep %p\n",
134 	       __func__, ib_event_msg(event->event),
135 		event->device->name, context);
136 	if (ep->rep_connected == 1) {
137 		ep->rep_connected = -EIO;
138 		rpcrdma_conn_func(ep);
139 		wake_up_all(&ep->rep_connect_wait);
140 	}
141 }
142 
143 static void
144 rpcrdma_sendcq_process_wc(struct ib_wc *wc)
145 {
146 	/* WARNING: Only wr_id and status are reliable at this point */
147 	if (wc->wr_id == RPCRDMA_IGNORE_COMPLETION) {
148 		if (wc->status != IB_WC_SUCCESS &&
149 		    wc->status != IB_WC_WR_FLUSH_ERR)
150 			pr_err("RPC:       %s: SEND: %s\n",
151 			       __func__, ib_wc_status_msg(wc->status));
152 	} else {
153 		struct rpcrdma_mw *r;
154 
155 		r = (struct rpcrdma_mw *)(unsigned long)wc->wr_id;
156 		r->mw_sendcompletion(wc);
157 	}
158 }
159 
160 static int
161 rpcrdma_sendcq_poll(struct ib_cq *cq, struct rpcrdma_ep *ep)
162 {
163 	struct ib_wc *wcs;
164 	int budget, count, rc;
165 
166 	budget = RPCRDMA_WC_BUDGET / RPCRDMA_POLLSIZE;
167 	do {
168 		wcs = ep->rep_send_wcs;
169 
170 		rc = ib_poll_cq(cq, RPCRDMA_POLLSIZE, wcs);
171 		if (rc <= 0)
172 			return rc;
173 
174 		count = rc;
175 		while (count-- > 0)
176 			rpcrdma_sendcq_process_wc(wcs++);
177 	} while (rc == RPCRDMA_POLLSIZE && --budget);
178 	return 0;
179 }
180 
181 /*
182  * Handle send, fast_reg_mr, and local_inv completions.
183  *
184  * Send events are typically suppressed and thus do not result
185  * in an upcall. Occasionally one is signaled, however. This
186  * prevents the provider's completion queue from wrapping and
187  * losing a completion.
188  */
189 static void
190 rpcrdma_sendcq_upcall(struct ib_cq *cq, void *cq_context)
191 {
192 	struct rpcrdma_ep *ep = (struct rpcrdma_ep *)cq_context;
193 	int rc;
194 
195 	rc = rpcrdma_sendcq_poll(cq, ep);
196 	if (rc) {
197 		dprintk("RPC:       %s: ib_poll_cq failed: %i\n",
198 			__func__, rc);
199 		return;
200 	}
201 
202 	rc = ib_req_notify_cq(cq,
203 			IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS);
204 	if (rc == 0)
205 		return;
206 	if (rc < 0) {
207 		dprintk("RPC:       %s: ib_req_notify_cq failed: %i\n",
208 			__func__, rc);
209 		return;
210 	}
211 
212 	rpcrdma_sendcq_poll(cq, ep);
213 }
214 
215 static void
216 rpcrdma_recvcq_process_wc(struct ib_wc *wc, struct list_head *sched_list)
217 {
218 	struct rpcrdma_rep *rep =
219 			(struct rpcrdma_rep *)(unsigned long)wc->wr_id;
220 
221 	/* WARNING: Only wr_id and status are reliable at this point */
222 	if (wc->status != IB_WC_SUCCESS)
223 		goto out_fail;
224 
225 	/* status == SUCCESS means all fields in wc are trustworthy */
226 	if (wc->opcode != IB_WC_RECV)
227 		return;
228 
229 	dprintk("RPC:       %s: rep %p opcode 'recv', length %u: success\n",
230 		__func__, rep, wc->byte_len);
231 
232 	rep->rr_len = wc->byte_len;
233 	ib_dma_sync_single_for_cpu(rep->rr_device,
234 				   rdmab_addr(rep->rr_rdmabuf),
235 				   rep->rr_len, DMA_FROM_DEVICE);
236 	prefetch(rdmab_to_msg(rep->rr_rdmabuf));
237 
238 out_schedule:
239 	list_add_tail(&rep->rr_list, sched_list);
240 	return;
241 out_fail:
242 	if (wc->status != IB_WC_WR_FLUSH_ERR)
243 		pr_err("RPC:       %s: rep %p: %s\n",
244 		       __func__, rep, ib_wc_status_msg(wc->status));
245 	rep->rr_len = ~0U;
246 	goto out_schedule;
247 }
248 
249 static int
250 rpcrdma_recvcq_poll(struct ib_cq *cq, struct rpcrdma_ep *ep)
251 {
252 	struct list_head sched_list;
253 	struct ib_wc *wcs;
254 	int budget, count, rc;
255 
256 	INIT_LIST_HEAD(&sched_list);
257 	budget = RPCRDMA_WC_BUDGET / RPCRDMA_POLLSIZE;
258 	do {
259 		wcs = ep->rep_recv_wcs;
260 
261 		rc = ib_poll_cq(cq, RPCRDMA_POLLSIZE, wcs);
262 		if (rc <= 0)
263 			goto out_schedule;
264 
265 		count = rc;
266 		while (count-- > 0)
267 			rpcrdma_recvcq_process_wc(wcs++, &sched_list);
268 	} while (rc == RPCRDMA_POLLSIZE && --budget);
269 	rc = 0;
270 
271 out_schedule:
272 	rpcrdma_schedule_tasklet(&sched_list);
273 	return rc;
274 }
275 
276 /*
277  * Handle receive completions.
278  *
279  * It is reentrant but processes single events in order to maintain
280  * ordering of receives to keep server credits.
281  *
282  * It is the responsibility of the scheduled tasklet to return
283  * recv buffers to the pool. NOTE: this affects synchronization of
284  * connection shutdown. That is, the structures required for
285  * the completion of the reply handler must remain intact until
286  * all memory has been reclaimed.
287  */
288 static void
289 rpcrdma_recvcq_upcall(struct ib_cq *cq, void *cq_context)
290 {
291 	struct rpcrdma_ep *ep = (struct rpcrdma_ep *)cq_context;
292 	int rc;
293 
294 	rc = rpcrdma_recvcq_poll(cq, ep);
295 	if (rc) {
296 		dprintk("RPC:       %s: ib_poll_cq failed: %i\n",
297 			__func__, rc);
298 		return;
299 	}
300 
301 	rc = ib_req_notify_cq(cq,
302 			IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS);
303 	if (rc == 0)
304 		return;
305 	if (rc < 0) {
306 		dprintk("RPC:       %s: ib_req_notify_cq failed: %i\n",
307 			__func__, rc);
308 		return;
309 	}
310 
311 	rpcrdma_recvcq_poll(cq, ep);
312 }
313 
314 static void
315 rpcrdma_flush_cqs(struct rpcrdma_ep *ep)
316 {
317 	struct ib_wc wc;
318 	LIST_HEAD(sched_list);
319 
320 	while (ib_poll_cq(ep->rep_attr.recv_cq, 1, &wc) > 0)
321 		rpcrdma_recvcq_process_wc(&wc, &sched_list);
322 	if (!list_empty(&sched_list))
323 		rpcrdma_schedule_tasklet(&sched_list);
324 	while (ib_poll_cq(ep->rep_attr.send_cq, 1, &wc) > 0)
325 		rpcrdma_sendcq_process_wc(&wc);
326 }
327 
328 static int
329 rpcrdma_conn_upcall(struct rdma_cm_id *id, struct rdma_cm_event *event)
330 {
331 	struct rpcrdma_xprt *xprt = id->context;
332 	struct rpcrdma_ia *ia = &xprt->rx_ia;
333 	struct rpcrdma_ep *ep = &xprt->rx_ep;
334 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
335 	struct sockaddr *sap = (struct sockaddr *)&ep->rep_remote_addr;
336 #endif
337 	struct ib_qp_attr *attr = &ia->ri_qp_attr;
338 	struct ib_qp_init_attr *iattr = &ia->ri_qp_init_attr;
339 	int connstate = 0;
340 
341 	switch (event->event) {
342 	case RDMA_CM_EVENT_ADDR_RESOLVED:
343 	case RDMA_CM_EVENT_ROUTE_RESOLVED:
344 		ia->ri_async_rc = 0;
345 		complete(&ia->ri_done);
346 		break;
347 	case RDMA_CM_EVENT_ADDR_ERROR:
348 		ia->ri_async_rc = -EHOSTUNREACH;
349 		dprintk("RPC:       %s: CM address resolution error, ep 0x%p\n",
350 			__func__, ep);
351 		complete(&ia->ri_done);
352 		break;
353 	case RDMA_CM_EVENT_ROUTE_ERROR:
354 		ia->ri_async_rc = -ENETUNREACH;
355 		dprintk("RPC:       %s: CM route resolution error, ep 0x%p\n",
356 			__func__, ep);
357 		complete(&ia->ri_done);
358 		break;
359 	case RDMA_CM_EVENT_ESTABLISHED:
360 		connstate = 1;
361 		ib_query_qp(ia->ri_id->qp, attr,
362 			    IB_QP_MAX_QP_RD_ATOMIC | IB_QP_MAX_DEST_RD_ATOMIC,
363 			    iattr);
364 		dprintk("RPC:       %s: %d responder resources"
365 			" (%d initiator)\n",
366 			__func__, attr->max_dest_rd_atomic,
367 			attr->max_rd_atomic);
368 		goto connected;
369 	case RDMA_CM_EVENT_CONNECT_ERROR:
370 		connstate = -ENOTCONN;
371 		goto connected;
372 	case RDMA_CM_EVENT_UNREACHABLE:
373 		connstate = -ENETDOWN;
374 		goto connected;
375 	case RDMA_CM_EVENT_REJECTED:
376 		connstate = -ECONNREFUSED;
377 		goto connected;
378 	case RDMA_CM_EVENT_DISCONNECTED:
379 		connstate = -ECONNABORTED;
380 		goto connected;
381 	case RDMA_CM_EVENT_DEVICE_REMOVAL:
382 		connstate = -ENODEV;
383 connected:
384 		dprintk("RPC:       %s: %sconnected\n",
385 					__func__, connstate > 0 ? "" : "dis");
386 		ep->rep_connected = connstate;
387 		rpcrdma_conn_func(ep);
388 		wake_up_all(&ep->rep_connect_wait);
389 		/*FALLTHROUGH*/
390 	default:
391 		dprintk("RPC:       %s: %pIS:%u (ep 0x%p): %s\n",
392 			__func__, sap, rpc_get_port(sap), ep,
393 			rdma_event_msg(event->event));
394 		break;
395 	}
396 
397 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
398 	if (connstate == 1) {
399 		int ird = attr->max_dest_rd_atomic;
400 		int tird = ep->rep_remote_cma.responder_resources;
401 
402 		pr_info("rpcrdma: connection to %pIS:%u on %s, memreg '%s', %d credits, %d responders%s\n",
403 			sap, rpc_get_port(sap),
404 			ia->ri_device->name,
405 			ia->ri_ops->ro_displayname,
406 			xprt->rx_buf.rb_max_requests,
407 			ird, ird < 4 && ird < tird / 2 ? " (low!)" : "");
408 	} else if (connstate < 0) {
409 		pr_info("rpcrdma: connection to %pIS:%u closed (%d)\n",
410 			sap, rpc_get_port(sap), connstate);
411 	}
412 #endif
413 
414 	return 0;
415 }
416 
417 static struct rdma_cm_id *
418 rpcrdma_create_id(struct rpcrdma_xprt *xprt,
419 			struct rpcrdma_ia *ia, struct sockaddr *addr)
420 {
421 	struct rdma_cm_id *id;
422 	int rc;
423 
424 	init_completion(&ia->ri_done);
425 
426 	id = rdma_create_id(rpcrdma_conn_upcall, xprt, RDMA_PS_TCP, IB_QPT_RC);
427 	if (IS_ERR(id)) {
428 		rc = PTR_ERR(id);
429 		dprintk("RPC:       %s: rdma_create_id() failed %i\n",
430 			__func__, rc);
431 		return id;
432 	}
433 
434 	ia->ri_async_rc = -ETIMEDOUT;
435 	rc = rdma_resolve_addr(id, NULL, addr, RDMA_RESOLVE_TIMEOUT);
436 	if (rc) {
437 		dprintk("RPC:       %s: rdma_resolve_addr() failed %i\n",
438 			__func__, rc);
439 		goto out;
440 	}
441 	wait_for_completion_interruptible_timeout(&ia->ri_done,
442 				msecs_to_jiffies(RDMA_RESOLVE_TIMEOUT) + 1);
443 	rc = ia->ri_async_rc;
444 	if (rc)
445 		goto out;
446 
447 	ia->ri_async_rc = -ETIMEDOUT;
448 	rc = rdma_resolve_route(id, RDMA_RESOLVE_TIMEOUT);
449 	if (rc) {
450 		dprintk("RPC:       %s: rdma_resolve_route() failed %i\n",
451 			__func__, rc);
452 		goto out;
453 	}
454 	wait_for_completion_interruptible_timeout(&ia->ri_done,
455 				msecs_to_jiffies(RDMA_RESOLVE_TIMEOUT) + 1);
456 	rc = ia->ri_async_rc;
457 	if (rc)
458 		goto out;
459 
460 	return id;
461 
462 out:
463 	rdma_destroy_id(id);
464 	return ERR_PTR(rc);
465 }
466 
467 /*
468  * Drain any cq, prior to teardown.
469  */
470 static void
471 rpcrdma_clean_cq(struct ib_cq *cq)
472 {
473 	struct ib_wc wc;
474 	int count = 0;
475 
476 	while (1 == ib_poll_cq(cq, 1, &wc))
477 		++count;
478 
479 	if (count)
480 		dprintk("RPC:       %s: flushed %d events (last 0x%x)\n",
481 			__func__, count, wc.opcode);
482 }
483 
484 /*
485  * Exported functions.
486  */
487 
488 /*
489  * Open and initialize an Interface Adapter.
490  *  o initializes fields of struct rpcrdma_ia, including
491  *    interface and provider attributes and protection zone.
492  */
493 int
494 rpcrdma_ia_open(struct rpcrdma_xprt *xprt, struct sockaddr *addr, int memreg)
495 {
496 	int rc, mem_priv;
497 	struct rpcrdma_ia *ia = &xprt->rx_ia;
498 	struct ib_device_attr *devattr = &ia->ri_devattr;
499 
500 	ia->ri_id = rpcrdma_create_id(xprt, ia, addr);
501 	if (IS_ERR(ia->ri_id)) {
502 		rc = PTR_ERR(ia->ri_id);
503 		goto out1;
504 	}
505 	ia->ri_device = ia->ri_id->device;
506 
507 	ia->ri_pd = ib_alloc_pd(ia->ri_device);
508 	if (IS_ERR(ia->ri_pd)) {
509 		rc = PTR_ERR(ia->ri_pd);
510 		dprintk("RPC:       %s: ib_alloc_pd() failed %i\n",
511 			__func__, rc);
512 		goto out2;
513 	}
514 
515 	rc = ib_query_device(ia->ri_device, devattr);
516 	if (rc) {
517 		dprintk("RPC:       %s: ib_query_device failed %d\n",
518 			__func__, rc);
519 		goto out3;
520 	}
521 
522 	if (devattr->device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY) {
523 		ia->ri_have_dma_lkey = 1;
524 		ia->ri_dma_lkey = ia->ri_device->local_dma_lkey;
525 	}
526 
527 	if (memreg == RPCRDMA_FRMR) {
528 		/* Requires both frmr reg and local dma lkey */
529 		if (((devattr->device_cap_flags &
530 		     (IB_DEVICE_MEM_MGT_EXTENSIONS|IB_DEVICE_LOCAL_DMA_LKEY)) !=
531 		    (IB_DEVICE_MEM_MGT_EXTENSIONS|IB_DEVICE_LOCAL_DMA_LKEY)) ||
532 		      (devattr->max_fast_reg_page_list_len == 0)) {
533 			dprintk("RPC:       %s: FRMR registration "
534 				"not supported by HCA\n", __func__);
535 			memreg = RPCRDMA_MTHCAFMR;
536 		}
537 	}
538 	if (memreg == RPCRDMA_MTHCAFMR) {
539 		if (!ia->ri_device->alloc_fmr) {
540 			dprintk("RPC:       %s: MTHCAFMR registration "
541 				"not supported by HCA\n", __func__);
542 			memreg = RPCRDMA_ALLPHYSICAL;
543 		}
544 	}
545 
546 	/*
547 	 * Optionally obtain an underlying physical identity mapping in
548 	 * order to do a memory window-based bind. This base registration
549 	 * is protected from remote access - that is enabled only by binding
550 	 * for the specific bytes targeted during each RPC operation, and
551 	 * revoked after the corresponding completion similar to a storage
552 	 * adapter.
553 	 */
554 	switch (memreg) {
555 	case RPCRDMA_FRMR:
556 		ia->ri_ops = &rpcrdma_frwr_memreg_ops;
557 		break;
558 	case RPCRDMA_ALLPHYSICAL:
559 		ia->ri_ops = &rpcrdma_physical_memreg_ops;
560 		mem_priv = IB_ACCESS_LOCAL_WRITE |
561 				IB_ACCESS_REMOTE_WRITE |
562 				IB_ACCESS_REMOTE_READ;
563 		goto register_setup;
564 	case RPCRDMA_MTHCAFMR:
565 		ia->ri_ops = &rpcrdma_fmr_memreg_ops;
566 		if (ia->ri_have_dma_lkey)
567 			break;
568 		mem_priv = IB_ACCESS_LOCAL_WRITE;
569 	register_setup:
570 		ia->ri_bind_mem = ib_get_dma_mr(ia->ri_pd, mem_priv);
571 		if (IS_ERR(ia->ri_bind_mem)) {
572 			printk(KERN_ALERT "%s: ib_get_dma_mr for "
573 				"phys register failed with %lX\n",
574 				__func__, PTR_ERR(ia->ri_bind_mem));
575 			rc = -ENOMEM;
576 			goto out3;
577 		}
578 		break;
579 	default:
580 		printk(KERN_ERR "RPC: Unsupported memory "
581 				"registration mode: %d\n", memreg);
582 		rc = -ENOMEM;
583 		goto out3;
584 	}
585 	dprintk("RPC:       %s: memory registration strategy is '%s'\n",
586 		__func__, ia->ri_ops->ro_displayname);
587 
588 	rwlock_init(&ia->ri_qplock);
589 	return 0;
590 
591 out3:
592 	ib_dealloc_pd(ia->ri_pd);
593 	ia->ri_pd = NULL;
594 out2:
595 	rdma_destroy_id(ia->ri_id);
596 	ia->ri_id = NULL;
597 out1:
598 	return rc;
599 }
600 
601 /*
602  * Clean up/close an IA.
603  *   o if event handles and PD have been initialized, free them.
604  *   o close the IA
605  */
606 void
607 rpcrdma_ia_close(struct rpcrdma_ia *ia)
608 {
609 	int rc;
610 
611 	dprintk("RPC:       %s: entering\n", __func__);
612 	if (ia->ri_bind_mem != NULL) {
613 		rc = ib_dereg_mr(ia->ri_bind_mem);
614 		dprintk("RPC:       %s: ib_dereg_mr returned %i\n",
615 			__func__, rc);
616 	}
617 
618 	if (ia->ri_id != NULL && !IS_ERR(ia->ri_id)) {
619 		if (ia->ri_id->qp)
620 			rdma_destroy_qp(ia->ri_id);
621 		rdma_destroy_id(ia->ri_id);
622 		ia->ri_id = NULL;
623 	}
624 
625 	/* If the pd is still busy, xprtrdma missed freeing a resource */
626 	if (ia->ri_pd && !IS_ERR(ia->ri_pd))
627 		WARN_ON(ib_dealloc_pd(ia->ri_pd));
628 }
629 
630 /*
631  * Create unconnected endpoint.
632  */
633 int
634 rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
635 				struct rpcrdma_create_data_internal *cdata)
636 {
637 	struct ib_device_attr *devattr = &ia->ri_devattr;
638 	struct ib_cq *sendcq, *recvcq;
639 	struct ib_cq_init_attr cq_attr = {};
640 	int rc, err;
641 
642 	/* check provider's send/recv wr limits */
643 	if (cdata->max_requests > devattr->max_qp_wr)
644 		cdata->max_requests = devattr->max_qp_wr;
645 
646 	ep->rep_attr.event_handler = rpcrdma_qp_async_error_upcall;
647 	ep->rep_attr.qp_context = ep;
648 	ep->rep_attr.srq = NULL;
649 	ep->rep_attr.cap.max_send_wr = cdata->max_requests;
650 	rc = ia->ri_ops->ro_open(ia, ep, cdata);
651 	if (rc)
652 		return rc;
653 	ep->rep_attr.cap.max_recv_wr = cdata->max_requests;
654 	ep->rep_attr.cap.max_send_sge = (cdata->padding ? 4 : 2);
655 	ep->rep_attr.cap.max_recv_sge = 1;
656 	ep->rep_attr.cap.max_inline_data = 0;
657 	ep->rep_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
658 	ep->rep_attr.qp_type = IB_QPT_RC;
659 	ep->rep_attr.port_num = ~0;
660 
661 	if (cdata->padding) {
662 		ep->rep_padbuf = rpcrdma_alloc_regbuf(ia, cdata->padding,
663 						      GFP_KERNEL);
664 		if (IS_ERR(ep->rep_padbuf))
665 			return PTR_ERR(ep->rep_padbuf);
666 	} else
667 		ep->rep_padbuf = NULL;
668 
669 	dprintk("RPC:       %s: requested max: dtos: send %d recv %d; "
670 		"iovs: send %d recv %d\n",
671 		__func__,
672 		ep->rep_attr.cap.max_send_wr,
673 		ep->rep_attr.cap.max_recv_wr,
674 		ep->rep_attr.cap.max_send_sge,
675 		ep->rep_attr.cap.max_recv_sge);
676 
677 	/* set trigger for requesting send completion */
678 	ep->rep_cqinit = ep->rep_attr.cap.max_send_wr/2 - 1;
679 	if (ep->rep_cqinit > RPCRDMA_MAX_UNSIGNALED_SENDS)
680 		ep->rep_cqinit = RPCRDMA_MAX_UNSIGNALED_SENDS;
681 	else if (ep->rep_cqinit <= 2)
682 		ep->rep_cqinit = 0;
683 	INIT_CQCOUNT(ep);
684 	init_waitqueue_head(&ep->rep_connect_wait);
685 	INIT_DELAYED_WORK(&ep->rep_connect_worker, rpcrdma_connect_worker);
686 
687 	cq_attr.cqe = ep->rep_attr.cap.max_send_wr + 1;
688 	sendcq = ib_create_cq(ia->ri_device, rpcrdma_sendcq_upcall,
689 			      rpcrdma_cq_async_error_upcall, ep, &cq_attr);
690 	if (IS_ERR(sendcq)) {
691 		rc = PTR_ERR(sendcq);
692 		dprintk("RPC:       %s: failed to create send CQ: %i\n",
693 			__func__, rc);
694 		goto out1;
695 	}
696 
697 	rc = ib_req_notify_cq(sendcq, IB_CQ_NEXT_COMP);
698 	if (rc) {
699 		dprintk("RPC:       %s: ib_req_notify_cq failed: %i\n",
700 			__func__, rc);
701 		goto out2;
702 	}
703 
704 	cq_attr.cqe = ep->rep_attr.cap.max_recv_wr + 1;
705 	recvcq = ib_create_cq(ia->ri_device, rpcrdma_recvcq_upcall,
706 			      rpcrdma_cq_async_error_upcall, ep, &cq_attr);
707 	if (IS_ERR(recvcq)) {
708 		rc = PTR_ERR(recvcq);
709 		dprintk("RPC:       %s: failed to create recv CQ: %i\n",
710 			__func__, rc);
711 		goto out2;
712 	}
713 
714 	rc = ib_req_notify_cq(recvcq, IB_CQ_NEXT_COMP);
715 	if (rc) {
716 		dprintk("RPC:       %s: ib_req_notify_cq failed: %i\n",
717 			__func__, rc);
718 		ib_destroy_cq(recvcq);
719 		goto out2;
720 	}
721 
722 	ep->rep_attr.send_cq = sendcq;
723 	ep->rep_attr.recv_cq = recvcq;
724 
725 	/* Initialize cma parameters */
726 
727 	/* RPC/RDMA does not use private data */
728 	ep->rep_remote_cma.private_data = NULL;
729 	ep->rep_remote_cma.private_data_len = 0;
730 
731 	/* Client offers RDMA Read but does not initiate */
732 	ep->rep_remote_cma.initiator_depth = 0;
733 	if (devattr->max_qp_rd_atom > 32)	/* arbitrary but <= 255 */
734 		ep->rep_remote_cma.responder_resources = 32;
735 	else
736 		ep->rep_remote_cma.responder_resources =
737 						devattr->max_qp_rd_atom;
738 
739 	ep->rep_remote_cma.retry_count = 7;
740 	ep->rep_remote_cma.flow_control = 0;
741 	ep->rep_remote_cma.rnr_retry_count = 0;
742 
743 	return 0;
744 
745 out2:
746 	err = ib_destroy_cq(sendcq);
747 	if (err)
748 		dprintk("RPC:       %s: ib_destroy_cq returned %i\n",
749 			__func__, err);
750 out1:
751 	rpcrdma_free_regbuf(ia, ep->rep_padbuf);
752 	return rc;
753 }
754 
755 /*
756  * rpcrdma_ep_destroy
757  *
758  * Disconnect and destroy endpoint. After this, the only
759  * valid operations on the ep are to free it (if dynamically
760  * allocated) or re-create it.
761  */
762 void
763 rpcrdma_ep_destroy(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
764 {
765 	int rc;
766 
767 	dprintk("RPC:       %s: entering, connected is %d\n",
768 		__func__, ep->rep_connected);
769 
770 	cancel_delayed_work_sync(&ep->rep_connect_worker);
771 
772 	if (ia->ri_id->qp) {
773 		rpcrdma_ep_disconnect(ep, ia);
774 		rdma_destroy_qp(ia->ri_id);
775 		ia->ri_id->qp = NULL;
776 	}
777 
778 	rpcrdma_free_regbuf(ia, ep->rep_padbuf);
779 
780 	rpcrdma_clean_cq(ep->rep_attr.recv_cq);
781 	rc = ib_destroy_cq(ep->rep_attr.recv_cq);
782 	if (rc)
783 		dprintk("RPC:       %s: ib_destroy_cq returned %i\n",
784 			__func__, rc);
785 
786 	rpcrdma_clean_cq(ep->rep_attr.send_cq);
787 	rc = ib_destroy_cq(ep->rep_attr.send_cq);
788 	if (rc)
789 		dprintk("RPC:       %s: ib_destroy_cq returned %i\n",
790 			__func__, rc);
791 }
792 
793 /*
794  * Connect unconnected endpoint.
795  */
796 int
797 rpcrdma_ep_connect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
798 {
799 	struct rdma_cm_id *id, *old;
800 	int rc = 0;
801 	int retry_count = 0;
802 
803 	if (ep->rep_connected != 0) {
804 		struct rpcrdma_xprt *xprt;
805 retry:
806 		dprintk("RPC:       %s: reconnecting...\n", __func__);
807 
808 		rpcrdma_ep_disconnect(ep, ia);
809 		rpcrdma_flush_cqs(ep);
810 
811 		xprt = container_of(ia, struct rpcrdma_xprt, rx_ia);
812 		id = rpcrdma_create_id(xprt, ia,
813 				(struct sockaddr *)&xprt->rx_data.addr);
814 		if (IS_ERR(id)) {
815 			rc = -EHOSTUNREACH;
816 			goto out;
817 		}
818 		/* TEMP TEMP TEMP - fail if new device:
819 		 * Deregister/remarshal *all* requests!
820 		 * Close and recreate adapter, pd, etc!
821 		 * Re-determine all attributes still sane!
822 		 * More stuff I haven't thought of!
823 		 * Rrrgh!
824 		 */
825 		if (ia->ri_device != id->device) {
826 			printk("RPC:       %s: can't reconnect on "
827 				"different device!\n", __func__);
828 			rdma_destroy_id(id);
829 			rc = -ENETUNREACH;
830 			goto out;
831 		}
832 		/* END TEMP */
833 		rc = rdma_create_qp(id, ia->ri_pd, &ep->rep_attr);
834 		if (rc) {
835 			dprintk("RPC:       %s: rdma_create_qp failed %i\n",
836 				__func__, rc);
837 			rdma_destroy_id(id);
838 			rc = -ENETUNREACH;
839 			goto out;
840 		}
841 
842 		write_lock(&ia->ri_qplock);
843 		old = ia->ri_id;
844 		ia->ri_id = id;
845 		write_unlock(&ia->ri_qplock);
846 
847 		rdma_destroy_qp(old);
848 		rdma_destroy_id(old);
849 	} else {
850 		dprintk("RPC:       %s: connecting...\n", __func__);
851 		rc = rdma_create_qp(ia->ri_id, ia->ri_pd, &ep->rep_attr);
852 		if (rc) {
853 			dprintk("RPC:       %s: rdma_create_qp failed %i\n",
854 				__func__, rc);
855 			/* do not update ep->rep_connected */
856 			return -ENETUNREACH;
857 		}
858 	}
859 
860 	ep->rep_connected = 0;
861 
862 	rc = rdma_connect(ia->ri_id, &ep->rep_remote_cma);
863 	if (rc) {
864 		dprintk("RPC:       %s: rdma_connect() failed with %i\n",
865 				__func__, rc);
866 		goto out;
867 	}
868 
869 	wait_event_interruptible(ep->rep_connect_wait, ep->rep_connected != 0);
870 
871 	/*
872 	 * Check state. A non-peer reject indicates no listener
873 	 * (ECONNREFUSED), which may be a transient state. All
874 	 * others indicate a transport condition which has already
875 	 * undergone a best-effort.
876 	 */
877 	if (ep->rep_connected == -ECONNREFUSED &&
878 	    ++retry_count <= RDMA_CONNECT_RETRY_MAX) {
879 		dprintk("RPC:       %s: non-peer_reject, retry\n", __func__);
880 		goto retry;
881 	}
882 	if (ep->rep_connected <= 0) {
883 		/* Sometimes, the only way to reliably connect to remote
884 		 * CMs is to use same nonzero values for ORD and IRD. */
885 		if (retry_count++ <= RDMA_CONNECT_RETRY_MAX + 1 &&
886 		    (ep->rep_remote_cma.responder_resources == 0 ||
887 		     ep->rep_remote_cma.initiator_depth !=
888 				ep->rep_remote_cma.responder_resources)) {
889 			if (ep->rep_remote_cma.responder_resources == 0)
890 				ep->rep_remote_cma.responder_resources = 1;
891 			ep->rep_remote_cma.initiator_depth =
892 				ep->rep_remote_cma.responder_resources;
893 			goto retry;
894 		}
895 		rc = ep->rep_connected;
896 	} else {
897 		dprintk("RPC:       %s: connected\n", __func__);
898 	}
899 
900 out:
901 	if (rc)
902 		ep->rep_connected = rc;
903 	return rc;
904 }
905 
906 /*
907  * rpcrdma_ep_disconnect
908  *
909  * This is separate from destroy to facilitate the ability
910  * to reconnect without recreating the endpoint.
911  *
912  * This call is not reentrant, and must not be made in parallel
913  * on the same endpoint.
914  */
915 void
916 rpcrdma_ep_disconnect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
917 {
918 	int rc;
919 
920 	rpcrdma_flush_cqs(ep);
921 	rc = rdma_disconnect(ia->ri_id);
922 	if (!rc) {
923 		/* returns without wait if not connected */
924 		wait_event_interruptible(ep->rep_connect_wait,
925 							ep->rep_connected != 1);
926 		dprintk("RPC:       %s: after wait, %sconnected\n", __func__,
927 			(ep->rep_connected == 1) ? "still " : "dis");
928 	} else {
929 		dprintk("RPC:       %s: rdma_disconnect %i\n", __func__, rc);
930 		ep->rep_connected = rc;
931 	}
932 }
933 
934 static struct rpcrdma_req *
935 rpcrdma_create_req(struct rpcrdma_xprt *r_xprt)
936 {
937 	struct rpcrdma_req *req;
938 
939 	req = kzalloc(sizeof(*req), GFP_KERNEL);
940 	if (req == NULL)
941 		return ERR_PTR(-ENOMEM);
942 
943 	req->rl_buffer = &r_xprt->rx_buf;
944 	return req;
945 }
946 
947 static struct rpcrdma_rep *
948 rpcrdma_create_rep(struct rpcrdma_xprt *r_xprt)
949 {
950 	struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data;
951 	struct rpcrdma_ia *ia = &r_xprt->rx_ia;
952 	struct rpcrdma_rep *rep;
953 	int rc;
954 
955 	rc = -ENOMEM;
956 	rep = kzalloc(sizeof(*rep), GFP_KERNEL);
957 	if (rep == NULL)
958 		goto out;
959 
960 	rep->rr_rdmabuf = rpcrdma_alloc_regbuf(ia, cdata->inline_rsize,
961 					       GFP_KERNEL);
962 	if (IS_ERR(rep->rr_rdmabuf)) {
963 		rc = PTR_ERR(rep->rr_rdmabuf);
964 		goto out_free;
965 	}
966 
967 	rep->rr_device = ia->ri_device;
968 	rep->rr_rxprt = r_xprt;
969 	return rep;
970 
971 out_free:
972 	kfree(rep);
973 out:
974 	return ERR_PTR(rc);
975 }
976 
977 int
978 rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt)
979 {
980 	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
981 	struct rpcrdma_ia *ia = &r_xprt->rx_ia;
982 	struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data;
983 	char *p;
984 	size_t len;
985 	int i, rc;
986 
987 	buf->rb_max_requests = cdata->max_requests;
988 	spin_lock_init(&buf->rb_lock);
989 
990 	/* Need to allocate:
991 	 *   1.  arrays for send and recv pointers
992 	 *   2.  arrays of struct rpcrdma_req to fill in pointers
993 	 *   3.  array of struct rpcrdma_rep for replies
994 	 * Send/recv buffers in req/rep need to be registered
995 	 */
996 	len = buf->rb_max_requests *
997 		(sizeof(struct rpcrdma_req *) + sizeof(struct rpcrdma_rep *));
998 
999 	p = kzalloc(len, GFP_KERNEL);
1000 	if (p == NULL) {
1001 		dprintk("RPC:       %s: req_t/rep_t/pad kzalloc(%zd) failed\n",
1002 			__func__, len);
1003 		rc = -ENOMEM;
1004 		goto out;
1005 	}
1006 	buf->rb_pool = p;	/* for freeing it later */
1007 
1008 	buf->rb_send_bufs = (struct rpcrdma_req **) p;
1009 	p = (char *) &buf->rb_send_bufs[buf->rb_max_requests];
1010 	buf->rb_recv_bufs = (struct rpcrdma_rep **) p;
1011 	p = (char *) &buf->rb_recv_bufs[buf->rb_max_requests];
1012 
1013 	rc = ia->ri_ops->ro_init(r_xprt);
1014 	if (rc)
1015 		goto out;
1016 
1017 	for (i = 0; i < buf->rb_max_requests; i++) {
1018 		struct rpcrdma_req *req;
1019 		struct rpcrdma_rep *rep;
1020 
1021 		req = rpcrdma_create_req(r_xprt);
1022 		if (IS_ERR(req)) {
1023 			dprintk("RPC:       %s: request buffer %d alloc"
1024 				" failed\n", __func__, i);
1025 			rc = PTR_ERR(req);
1026 			goto out;
1027 		}
1028 		buf->rb_send_bufs[i] = req;
1029 
1030 		rep = rpcrdma_create_rep(r_xprt);
1031 		if (IS_ERR(rep)) {
1032 			dprintk("RPC:       %s: reply buffer %d alloc failed\n",
1033 				__func__, i);
1034 			rc = PTR_ERR(rep);
1035 			goto out;
1036 		}
1037 		buf->rb_recv_bufs[i] = rep;
1038 	}
1039 
1040 	return 0;
1041 out:
1042 	rpcrdma_buffer_destroy(buf);
1043 	return rc;
1044 }
1045 
1046 static void
1047 rpcrdma_destroy_rep(struct rpcrdma_ia *ia, struct rpcrdma_rep *rep)
1048 {
1049 	if (!rep)
1050 		return;
1051 
1052 	rpcrdma_free_regbuf(ia, rep->rr_rdmabuf);
1053 	kfree(rep);
1054 }
1055 
1056 static void
1057 rpcrdma_destroy_req(struct rpcrdma_ia *ia, struct rpcrdma_req *req)
1058 {
1059 	if (!req)
1060 		return;
1061 
1062 	rpcrdma_free_regbuf(ia, req->rl_sendbuf);
1063 	rpcrdma_free_regbuf(ia, req->rl_rdmabuf);
1064 	kfree(req);
1065 }
1066 
1067 void
1068 rpcrdma_buffer_destroy(struct rpcrdma_buffer *buf)
1069 {
1070 	struct rpcrdma_ia *ia = rdmab_to_ia(buf);
1071 	int i;
1072 
1073 	/* clean up in reverse order from create
1074 	 *   1.  recv mr memory (mr free, then kfree)
1075 	 *   2.  send mr memory (mr free, then kfree)
1076 	 *   3.  MWs
1077 	 */
1078 	dprintk("RPC:       %s: entering\n", __func__);
1079 
1080 	for (i = 0; i < buf->rb_max_requests; i++) {
1081 		if (buf->rb_recv_bufs)
1082 			rpcrdma_destroy_rep(ia, buf->rb_recv_bufs[i]);
1083 		if (buf->rb_send_bufs)
1084 			rpcrdma_destroy_req(ia, buf->rb_send_bufs[i]);
1085 	}
1086 
1087 	ia->ri_ops->ro_destroy(buf);
1088 
1089 	kfree(buf->rb_pool);
1090 }
1091 
1092 struct rpcrdma_mw *
1093 rpcrdma_get_mw(struct rpcrdma_xprt *r_xprt)
1094 {
1095 	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
1096 	struct rpcrdma_mw *mw = NULL;
1097 
1098 	spin_lock(&buf->rb_mwlock);
1099 	if (!list_empty(&buf->rb_mws)) {
1100 		mw = list_first_entry(&buf->rb_mws,
1101 				      struct rpcrdma_mw, mw_list);
1102 		list_del_init(&mw->mw_list);
1103 	}
1104 	spin_unlock(&buf->rb_mwlock);
1105 
1106 	if (!mw)
1107 		pr_err("RPC:       %s: no MWs available\n", __func__);
1108 	return mw;
1109 }
1110 
1111 void
1112 rpcrdma_put_mw(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mw *mw)
1113 {
1114 	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
1115 
1116 	spin_lock(&buf->rb_mwlock);
1117 	list_add_tail(&mw->mw_list, &buf->rb_mws);
1118 	spin_unlock(&buf->rb_mwlock);
1119 }
1120 
1121 static void
1122 rpcrdma_buffer_put_sendbuf(struct rpcrdma_req *req, struct rpcrdma_buffer *buf)
1123 {
1124 	buf->rb_send_bufs[--buf->rb_send_index] = req;
1125 	req->rl_niovs = 0;
1126 	if (req->rl_reply) {
1127 		buf->rb_recv_bufs[--buf->rb_recv_index] = req->rl_reply;
1128 		req->rl_reply = NULL;
1129 	}
1130 }
1131 
1132 /*
1133  * Get a set of request/reply buffers.
1134  *
1135  * Reply buffer (if needed) is attached to send buffer upon return.
1136  * Rule:
1137  *    rb_send_index and rb_recv_index MUST always be pointing to the
1138  *    *next* available buffer (non-NULL). They are incremented after
1139  *    removing buffers, and decremented *before* returning them.
1140  */
1141 struct rpcrdma_req *
1142 rpcrdma_buffer_get(struct rpcrdma_buffer *buffers)
1143 {
1144 	struct rpcrdma_req *req;
1145 	unsigned long flags;
1146 
1147 	spin_lock_irqsave(&buffers->rb_lock, flags);
1148 
1149 	if (buffers->rb_send_index == buffers->rb_max_requests) {
1150 		spin_unlock_irqrestore(&buffers->rb_lock, flags);
1151 		dprintk("RPC:       %s: out of request buffers\n", __func__);
1152 		return ((struct rpcrdma_req *)NULL);
1153 	}
1154 
1155 	req = buffers->rb_send_bufs[buffers->rb_send_index];
1156 	if (buffers->rb_send_index < buffers->rb_recv_index) {
1157 		dprintk("RPC:       %s: %d extra receives outstanding (ok)\n",
1158 			__func__,
1159 			buffers->rb_recv_index - buffers->rb_send_index);
1160 		req->rl_reply = NULL;
1161 	} else {
1162 		req->rl_reply = buffers->rb_recv_bufs[buffers->rb_recv_index];
1163 		buffers->rb_recv_bufs[buffers->rb_recv_index++] = NULL;
1164 	}
1165 	buffers->rb_send_bufs[buffers->rb_send_index++] = NULL;
1166 
1167 	spin_unlock_irqrestore(&buffers->rb_lock, flags);
1168 	return req;
1169 }
1170 
1171 /*
1172  * Put request/reply buffers back into pool.
1173  * Pre-decrement counter/array index.
1174  */
1175 void
1176 rpcrdma_buffer_put(struct rpcrdma_req *req)
1177 {
1178 	struct rpcrdma_buffer *buffers = req->rl_buffer;
1179 	unsigned long flags;
1180 
1181 	spin_lock_irqsave(&buffers->rb_lock, flags);
1182 	rpcrdma_buffer_put_sendbuf(req, buffers);
1183 	spin_unlock_irqrestore(&buffers->rb_lock, flags);
1184 }
1185 
1186 /*
1187  * Recover reply buffers from pool.
1188  * This happens when recovering from error conditions.
1189  * Post-increment counter/array index.
1190  */
1191 void
1192 rpcrdma_recv_buffer_get(struct rpcrdma_req *req)
1193 {
1194 	struct rpcrdma_buffer *buffers = req->rl_buffer;
1195 	unsigned long flags;
1196 
1197 	spin_lock_irqsave(&buffers->rb_lock, flags);
1198 	if (buffers->rb_recv_index < buffers->rb_max_requests) {
1199 		req->rl_reply = buffers->rb_recv_bufs[buffers->rb_recv_index];
1200 		buffers->rb_recv_bufs[buffers->rb_recv_index++] = NULL;
1201 	}
1202 	spin_unlock_irqrestore(&buffers->rb_lock, flags);
1203 }
1204 
1205 /*
1206  * Put reply buffers back into pool when not attached to
1207  * request. This happens in error conditions.
1208  */
1209 void
1210 rpcrdma_recv_buffer_put(struct rpcrdma_rep *rep)
1211 {
1212 	struct rpcrdma_buffer *buffers = &rep->rr_rxprt->rx_buf;
1213 	unsigned long flags;
1214 
1215 	spin_lock_irqsave(&buffers->rb_lock, flags);
1216 	buffers->rb_recv_bufs[--buffers->rb_recv_index] = rep;
1217 	spin_unlock_irqrestore(&buffers->rb_lock, flags);
1218 }
1219 
1220 /*
1221  * Wrappers for internal-use kmalloc memory registration, used by buffer code.
1222  */
1223 
1224 void
1225 rpcrdma_mapping_error(struct rpcrdma_mr_seg *seg)
1226 {
1227 	dprintk("RPC:       map_one: offset %p iova %llx len %zu\n",
1228 		seg->mr_offset,
1229 		(unsigned long long)seg->mr_dma, seg->mr_dmalen);
1230 }
1231 
1232 static int
1233 rpcrdma_register_internal(struct rpcrdma_ia *ia, void *va, int len,
1234 				struct ib_mr **mrp, struct ib_sge *iov)
1235 {
1236 	struct ib_phys_buf ipb;
1237 	struct ib_mr *mr;
1238 	int rc;
1239 
1240 	/*
1241 	 * All memory passed here was kmalloc'ed, therefore phys-contiguous.
1242 	 */
1243 	iov->addr = ib_dma_map_single(ia->ri_device,
1244 			va, len, DMA_BIDIRECTIONAL);
1245 	if (ib_dma_mapping_error(ia->ri_device, iov->addr))
1246 		return -ENOMEM;
1247 
1248 	iov->length = len;
1249 
1250 	if (ia->ri_have_dma_lkey) {
1251 		*mrp = NULL;
1252 		iov->lkey = ia->ri_dma_lkey;
1253 		return 0;
1254 	} else if (ia->ri_bind_mem != NULL) {
1255 		*mrp = NULL;
1256 		iov->lkey = ia->ri_bind_mem->lkey;
1257 		return 0;
1258 	}
1259 
1260 	ipb.addr = iov->addr;
1261 	ipb.size = iov->length;
1262 	mr = ib_reg_phys_mr(ia->ri_pd, &ipb, 1,
1263 			IB_ACCESS_LOCAL_WRITE, &iov->addr);
1264 
1265 	dprintk("RPC:       %s: phys convert: 0x%llx "
1266 			"registered 0x%llx length %d\n",
1267 			__func__, (unsigned long long)ipb.addr,
1268 			(unsigned long long)iov->addr, len);
1269 
1270 	if (IS_ERR(mr)) {
1271 		*mrp = NULL;
1272 		rc = PTR_ERR(mr);
1273 		dprintk("RPC:       %s: failed with %i\n", __func__, rc);
1274 	} else {
1275 		*mrp = mr;
1276 		iov->lkey = mr->lkey;
1277 		rc = 0;
1278 	}
1279 
1280 	return rc;
1281 }
1282 
1283 static int
1284 rpcrdma_deregister_internal(struct rpcrdma_ia *ia,
1285 				struct ib_mr *mr, struct ib_sge *iov)
1286 {
1287 	int rc;
1288 
1289 	ib_dma_unmap_single(ia->ri_device,
1290 			    iov->addr, iov->length, DMA_BIDIRECTIONAL);
1291 
1292 	if (NULL == mr)
1293 		return 0;
1294 
1295 	rc = ib_dereg_mr(mr);
1296 	if (rc)
1297 		dprintk("RPC:       %s: ib_dereg_mr failed %i\n", __func__, rc);
1298 	return rc;
1299 }
1300 
1301 /**
1302  * rpcrdma_alloc_regbuf - kmalloc and register memory for SEND/RECV buffers
1303  * @ia: controlling rpcrdma_ia
1304  * @size: size of buffer to be allocated, in bytes
1305  * @flags: GFP flags
1306  *
1307  * Returns pointer to private header of an area of internally
1308  * registered memory, or an ERR_PTR. The registered buffer follows
1309  * the end of the private header.
1310  *
1311  * xprtrdma uses a regbuf for posting an outgoing RDMA SEND, or for
1312  * receiving the payload of RDMA RECV operations. regbufs are not
1313  * used for RDMA READ/WRITE operations, thus are registered only for
1314  * LOCAL access.
1315  */
1316 struct rpcrdma_regbuf *
1317 rpcrdma_alloc_regbuf(struct rpcrdma_ia *ia, size_t size, gfp_t flags)
1318 {
1319 	struct rpcrdma_regbuf *rb;
1320 	int rc;
1321 
1322 	rc = -ENOMEM;
1323 	rb = kmalloc(sizeof(*rb) + size, flags);
1324 	if (rb == NULL)
1325 		goto out;
1326 
1327 	rb->rg_size = size;
1328 	rb->rg_owner = NULL;
1329 	rc = rpcrdma_register_internal(ia, rb->rg_base, size,
1330 				       &rb->rg_mr, &rb->rg_iov);
1331 	if (rc)
1332 		goto out_free;
1333 
1334 	return rb;
1335 
1336 out_free:
1337 	kfree(rb);
1338 out:
1339 	return ERR_PTR(rc);
1340 }
1341 
1342 /**
1343  * rpcrdma_free_regbuf - deregister and free registered buffer
1344  * @ia: controlling rpcrdma_ia
1345  * @rb: regbuf to be deregistered and freed
1346  */
1347 void
1348 rpcrdma_free_regbuf(struct rpcrdma_ia *ia, struct rpcrdma_regbuf *rb)
1349 {
1350 	if (rb) {
1351 		rpcrdma_deregister_internal(ia, rb->rg_mr, &rb->rg_iov);
1352 		kfree(rb);
1353 	}
1354 }
1355 
1356 /*
1357  * Prepost any receive buffer, then post send.
1358  *
1359  * Receive buffer is donated to hardware, reclaimed upon recv completion.
1360  */
1361 int
1362 rpcrdma_ep_post(struct rpcrdma_ia *ia,
1363 		struct rpcrdma_ep *ep,
1364 		struct rpcrdma_req *req)
1365 {
1366 	struct ib_send_wr send_wr, *send_wr_fail;
1367 	struct rpcrdma_rep *rep = req->rl_reply;
1368 	int rc;
1369 
1370 	if (rep) {
1371 		rc = rpcrdma_ep_post_recv(ia, ep, rep);
1372 		if (rc)
1373 			goto out;
1374 		req->rl_reply = NULL;
1375 	}
1376 
1377 	send_wr.next = NULL;
1378 	send_wr.wr_id = RPCRDMA_IGNORE_COMPLETION;
1379 	send_wr.sg_list = req->rl_send_iov;
1380 	send_wr.num_sge = req->rl_niovs;
1381 	send_wr.opcode = IB_WR_SEND;
1382 	if (send_wr.num_sge == 4)	/* no need to sync any pad (constant) */
1383 		ib_dma_sync_single_for_device(ia->ri_device,
1384 					      req->rl_send_iov[3].addr,
1385 					      req->rl_send_iov[3].length,
1386 					      DMA_TO_DEVICE);
1387 	ib_dma_sync_single_for_device(ia->ri_device,
1388 				      req->rl_send_iov[1].addr,
1389 				      req->rl_send_iov[1].length,
1390 				      DMA_TO_DEVICE);
1391 	ib_dma_sync_single_for_device(ia->ri_device,
1392 				      req->rl_send_iov[0].addr,
1393 				      req->rl_send_iov[0].length,
1394 				      DMA_TO_DEVICE);
1395 
1396 	if (DECR_CQCOUNT(ep) > 0)
1397 		send_wr.send_flags = 0;
1398 	else { /* Provider must take a send completion every now and then */
1399 		INIT_CQCOUNT(ep);
1400 		send_wr.send_flags = IB_SEND_SIGNALED;
1401 	}
1402 
1403 	rc = ib_post_send(ia->ri_id->qp, &send_wr, &send_wr_fail);
1404 	if (rc)
1405 		dprintk("RPC:       %s: ib_post_send returned %i\n", __func__,
1406 			rc);
1407 out:
1408 	return rc;
1409 }
1410 
1411 /*
1412  * (Re)post a receive buffer.
1413  */
1414 int
1415 rpcrdma_ep_post_recv(struct rpcrdma_ia *ia,
1416 		     struct rpcrdma_ep *ep,
1417 		     struct rpcrdma_rep *rep)
1418 {
1419 	struct ib_recv_wr recv_wr, *recv_wr_fail;
1420 	int rc;
1421 
1422 	recv_wr.next = NULL;
1423 	recv_wr.wr_id = (u64) (unsigned long) rep;
1424 	recv_wr.sg_list = &rep->rr_rdmabuf->rg_iov;
1425 	recv_wr.num_sge = 1;
1426 
1427 	ib_dma_sync_single_for_cpu(ia->ri_device,
1428 				   rdmab_addr(rep->rr_rdmabuf),
1429 				   rdmab_length(rep->rr_rdmabuf),
1430 				   DMA_BIDIRECTIONAL);
1431 
1432 	rc = ib_post_recv(ia->ri_id->qp, &recv_wr, &recv_wr_fail);
1433 
1434 	if (rc)
1435 		dprintk("RPC:       %s: ib_post_recv returned %i\n", __func__,
1436 			rc);
1437 	return rc;
1438 }
1439 
1440 /* How many chunk list items fit within our inline buffers?
1441  */
1442 unsigned int
1443 rpcrdma_max_segments(struct rpcrdma_xprt *r_xprt)
1444 {
1445 	struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data;
1446 	int bytes, segments;
1447 
1448 	bytes = min_t(unsigned int, cdata->inline_wsize, cdata->inline_rsize);
1449 	bytes -= RPCRDMA_HDRLEN_MIN;
1450 	if (bytes < sizeof(struct rpcrdma_segment) * 2) {
1451 		pr_warn("RPC:       %s: inline threshold too small\n",
1452 			__func__);
1453 		return 0;
1454 	}
1455 
1456 	segments = 1 << (fls(bytes / sizeof(struct rpcrdma_segment)) - 1);
1457 	dprintk("RPC:       %s: max chunk list size = %d segments\n",
1458 		__func__, segments);
1459 	return segments;
1460 }
1461