Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszer...
[sfrench/cifs-2.6.git] / net / sunrpc / xprtrdma / verbs.c
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 #include <linux/module.h> /* try_module_get()/module_put() */
56
57 #include "xprt_rdma.h"
58
59 /*
60  * Globals/Macros
61  */
62
63 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
64 # define RPCDBG_FACILITY        RPCDBG_TRANS
65 #endif
66
67 /*
68  * internal functions
69  */
70
71 static struct workqueue_struct *rpcrdma_receive_wq;
72
73 int
74 rpcrdma_alloc_wq(void)
75 {
76         struct workqueue_struct *recv_wq;
77
78         recv_wq = alloc_workqueue("xprtrdma_receive",
79                                   WQ_MEM_RECLAIM | WQ_UNBOUND | WQ_HIGHPRI,
80                                   0);
81         if (!recv_wq)
82                 return -ENOMEM;
83
84         rpcrdma_receive_wq = recv_wq;
85         return 0;
86 }
87
88 void
89 rpcrdma_destroy_wq(void)
90 {
91         struct workqueue_struct *wq;
92
93         if (rpcrdma_receive_wq) {
94                 wq = rpcrdma_receive_wq;
95                 rpcrdma_receive_wq = NULL;
96                 destroy_workqueue(wq);
97         }
98 }
99
100 static void
101 rpcrdma_qp_async_error_upcall(struct ib_event *event, void *context)
102 {
103         struct rpcrdma_ep *ep = context;
104
105         pr_err("RPC:       %s: %s on device %s ep %p\n",
106                __func__, ib_event_msg(event->event),
107                 event->device->name, context);
108         if (ep->rep_connected == 1) {
109                 ep->rep_connected = -EIO;
110                 rpcrdma_conn_func(ep);
111                 wake_up_all(&ep->rep_connect_wait);
112         }
113 }
114
115 static void
116 rpcrdma_cq_async_error_upcall(struct ib_event *event, void *context)
117 {
118         struct rpcrdma_ep *ep = context;
119
120         pr_err("RPC:       %s: %s on device %s ep %p\n",
121                __func__, ib_event_msg(event->event),
122                 event->device->name, context);
123         if (ep->rep_connected == 1) {
124                 ep->rep_connected = -EIO;
125                 rpcrdma_conn_func(ep);
126                 wake_up_all(&ep->rep_connect_wait);
127         }
128 }
129
130 static void
131 rpcrdma_sendcq_process_wc(struct ib_wc *wc)
132 {
133         /* WARNING: Only wr_id and status are reliable at this point */
134         if (wc->wr_id == RPCRDMA_IGNORE_COMPLETION) {
135                 if (wc->status != IB_WC_SUCCESS &&
136                     wc->status != IB_WC_WR_FLUSH_ERR)
137                         pr_err("RPC:       %s: SEND: %s\n",
138                                __func__, ib_wc_status_msg(wc->status));
139         } else {
140                 struct rpcrdma_mw *r;
141
142                 r = (struct rpcrdma_mw *)(unsigned long)wc->wr_id;
143                 r->mw_sendcompletion(wc);
144         }
145 }
146
147 /* The common case is a single send completion is waiting. By
148  * passing two WC entries to ib_poll_cq, a return code of 1
149  * means there is exactly one WC waiting and no more. We don't
150  * have to invoke ib_poll_cq again to know that the CQ has been
151  * properly drained.
152  */
153 static void
154 rpcrdma_sendcq_poll(struct ib_cq *cq)
155 {
156         struct ib_wc *pos, wcs[2];
157         int count, rc;
158
159         do {
160                 pos = wcs;
161
162                 rc = ib_poll_cq(cq, ARRAY_SIZE(wcs), pos);
163                 if (rc < 0)
164                         break;
165
166                 count = rc;
167                 while (count-- > 0)
168                         rpcrdma_sendcq_process_wc(pos++);
169         } while (rc == ARRAY_SIZE(wcs));
170         return;
171 }
172
173 /* Handle provider send completion upcalls.
174  */
175 static void
176 rpcrdma_sendcq_upcall(struct ib_cq *cq, void *cq_context)
177 {
178         do {
179                 rpcrdma_sendcq_poll(cq);
180         } while (ib_req_notify_cq(cq, IB_CQ_NEXT_COMP |
181                                   IB_CQ_REPORT_MISSED_EVENTS) > 0);
182 }
183
184 static void
185 rpcrdma_receive_worker(struct work_struct *work)
186 {
187         struct rpcrdma_rep *rep =
188                         container_of(work, struct rpcrdma_rep, rr_work);
189
190         rpcrdma_reply_handler(rep);
191 }
192
193 static void
194 rpcrdma_recvcq_process_wc(struct ib_wc *wc)
195 {
196         struct rpcrdma_rep *rep =
197                         (struct rpcrdma_rep *)(unsigned long)wc->wr_id;
198
199         /* WARNING: Only wr_id and status are reliable at this point */
200         if (wc->status != IB_WC_SUCCESS)
201                 goto out_fail;
202
203         /* status == SUCCESS means all fields in wc are trustworthy */
204         if (wc->opcode != IB_WC_RECV)
205                 return;
206
207         dprintk("RPC:       %s: rep %p opcode 'recv', length %u: success\n",
208                 __func__, rep, wc->byte_len);
209
210         rep->rr_len = wc->byte_len;
211         ib_dma_sync_single_for_cpu(rep->rr_device,
212                                    rdmab_addr(rep->rr_rdmabuf),
213                                    rep->rr_len, DMA_FROM_DEVICE);
214         prefetch(rdmab_to_msg(rep->rr_rdmabuf));
215
216 out_schedule:
217         queue_work(rpcrdma_receive_wq, &rep->rr_work);
218         return;
219
220 out_fail:
221         if (wc->status != IB_WC_WR_FLUSH_ERR)
222                 pr_err("RPC:       %s: rep %p: %s\n",
223                        __func__, rep, ib_wc_status_msg(wc->status));
224         rep->rr_len = RPCRDMA_BAD_LEN;
225         goto out_schedule;
226 }
227
228 /* The wc array is on stack: automatic memory is always CPU-local.
229  *
230  * struct ib_wc is 64 bytes, making the poll array potentially
231  * large. But this is at the bottom of the call chain. Further
232  * substantial work is done in another thread.
233  */
234 static void
235 rpcrdma_recvcq_poll(struct ib_cq *cq)
236 {
237         struct ib_wc *pos, wcs[4];
238         int count, rc;
239
240         do {
241                 pos = wcs;
242
243                 rc = ib_poll_cq(cq, ARRAY_SIZE(wcs), pos);
244                 if (rc < 0)
245                         break;
246
247                 count = rc;
248                 while (count-- > 0)
249                         rpcrdma_recvcq_process_wc(pos++);
250         } while (rc == ARRAY_SIZE(wcs));
251 }
252
253 /* Handle provider receive completion upcalls.
254  */
255 static void
256 rpcrdma_recvcq_upcall(struct ib_cq *cq, void *cq_context)
257 {
258         do {
259                 rpcrdma_recvcq_poll(cq);
260         } while (ib_req_notify_cq(cq, IB_CQ_NEXT_COMP |
261                                   IB_CQ_REPORT_MISSED_EVENTS) > 0);
262 }
263
264 static void
265 rpcrdma_flush_cqs(struct rpcrdma_ep *ep)
266 {
267         struct ib_wc wc;
268
269         while (ib_poll_cq(ep->rep_attr.recv_cq, 1, &wc) > 0)
270                 rpcrdma_recvcq_process_wc(&wc);
271         while (ib_poll_cq(ep->rep_attr.send_cq, 1, &wc) > 0)
272                 rpcrdma_sendcq_process_wc(&wc);
273 }
274
275 static int
276 rpcrdma_conn_upcall(struct rdma_cm_id *id, struct rdma_cm_event *event)
277 {
278         struct rpcrdma_xprt *xprt = id->context;
279         struct rpcrdma_ia *ia = &xprt->rx_ia;
280         struct rpcrdma_ep *ep = &xprt->rx_ep;
281 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
282         struct sockaddr *sap = (struct sockaddr *)&ep->rep_remote_addr;
283 #endif
284         struct ib_qp_attr *attr = &ia->ri_qp_attr;
285         struct ib_qp_init_attr *iattr = &ia->ri_qp_init_attr;
286         int connstate = 0;
287
288         switch (event->event) {
289         case RDMA_CM_EVENT_ADDR_RESOLVED:
290         case RDMA_CM_EVENT_ROUTE_RESOLVED:
291                 ia->ri_async_rc = 0;
292                 complete(&ia->ri_done);
293                 break;
294         case RDMA_CM_EVENT_ADDR_ERROR:
295                 ia->ri_async_rc = -EHOSTUNREACH;
296                 dprintk("RPC:       %s: CM address resolution error, ep 0x%p\n",
297                         __func__, ep);
298                 complete(&ia->ri_done);
299                 break;
300         case RDMA_CM_EVENT_ROUTE_ERROR:
301                 ia->ri_async_rc = -ENETUNREACH;
302                 dprintk("RPC:       %s: CM route resolution error, ep 0x%p\n",
303                         __func__, ep);
304                 complete(&ia->ri_done);
305                 break;
306         case RDMA_CM_EVENT_ESTABLISHED:
307                 connstate = 1;
308                 ib_query_qp(ia->ri_id->qp, attr,
309                             IB_QP_MAX_QP_RD_ATOMIC | IB_QP_MAX_DEST_RD_ATOMIC,
310                             iattr);
311                 dprintk("RPC:       %s: %d responder resources"
312                         " (%d initiator)\n",
313                         __func__, attr->max_dest_rd_atomic,
314                         attr->max_rd_atomic);
315                 goto connected;
316         case RDMA_CM_EVENT_CONNECT_ERROR:
317                 connstate = -ENOTCONN;
318                 goto connected;
319         case RDMA_CM_EVENT_UNREACHABLE:
320                 connstate = -ENETDOWN;
321                 goto connected;
322         case RDMA_CM_EVENT_REJECTED:
323                 connstate = -ECONNREFUSED;
324                 goto connected;
325         case RDMA_CM_EVENT_DISCONNECTED:
326                 connstate = -ECONNABORTED;
327                 goto connected;
328         case RDMA_CM_EVENT_DEVICE_REMOVAL:
329                 connstate = -ENODEV;
330 connected:
331                 dprintk("RPC:       %s: %sconnected\n",
332                                         __func__, connstate > 0 ? "" : "dis");
333                 ep->rep_connected = connstate;
334                 rpcrdma_conn_func(ep);
335                 wake_up_all(&ep->rep_connect_wait);
336                 /*FALLTHROUGH*/
337         default:
338                 dprintk("RPC:       %s: %pIS:%u (ep 0x%p): %s\n",
339                         __func__, sap, rpc_get_port(sap), ep,
340                         rdma_event_msg(event->event));
341                 break;
342         }
343
344 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
345         if (connstate == 1) {
346                 int ird = attr->max_dest_rd_atomic;
347                 int tird = ep->rep_remote_cma.responder_resources;
348
349                 pr_info("rpcrdma: connection to %pIS:%u on %s, memreg '%s', %d credits, %d responders%s\n",
350                         sap, rpc_get_port(sap),
351                         ia->ri_device->name,
352                         ia->ri_ops->ro_displayname,
353                         xprt->rx_buf.rb_max_requests,
354                         ird, ird < 4 && ird < tird / 2 ? " (low!)" : "");
355         } else if (connstate < 0) {
356                 pr_info("rpcrdma: connection to %pIS:%u closed (%d)\n",
357                         sap, rpc_get_port(sap), connstate);
358         }
359 #endif
360
361         return 0;
362 }
363
364 static void rpcrdma_destroy_id(struct rdma_cm_id *id)
365 {
366         if (id) {
367                 module_put(id->device->owner);
368                 rdma_destroy_id(id);
369         }
370 }
371
372 static struct rdma_cm_id *
373 rpcrdma_create_id(struct rpcrdma_xprt *xprt,
374                         struct rpcrdma_ia *ia, struct sockaddr *addr)
375 {
376         struct rdma_cm_id *id;
377         int rc;
378
379         init_completion(&ia->ri_done);
380
381         id = rdma_create_id(&init_net, rpcrdma_conn_upcall, xprt, RDMA_PS_TCP,
382                             IB_QPT_RC);
383         if (IS_ERR(id)) {
384                 rc = PTR_ERR(id);
385                 dprintk("RPC:       %s: rdma_create_id() failed %i\n",
386                         __func__, rc);
387                 return id;
388         }
389
390         ia->ri_async_rc = -ETIMEDOUT;
391         rc = rdma_resolve_addr(id, NULL, addr, RDMA_RESOLVE_TIMEOUT);
392         if (rc) {
393                 dprintk("RPC:       %s: rdma_resolve_addr() failed %i\n",
394                         __func__, rc);
395                 goto out;
396         }
397         wait_for_completion_interruptible_timeout(&ia->ri_done,
398                                 msecs_to_jiffies(RDMA_RESOLVE_TIMEOUT) + 1);
399
400         /* FIXME:
401          * Until xprtrdma supports DEVICE_REMOVAL, the provider must
402          * be pinned while there are active NFS/RDMA mounts to prevent
403          * hangs and crashes at umount time.
404          */
405         if (!ia->ri_async_rc && !try_module_get(id->device->owner)) {
406                 dprintk("RPC:       %s: Failed to get device module\n",
407                         __func__);
408                 ia->ri_async_rc = -ENODEV;
409         }
410         rc = ia->ri_async_rc;
411         if (rc)
412                 goto out;
413
414         ia->ri_async_rc = -ETIMEDOUT;
415         rc = rdma_resolve_route(id, RDMA_RESOLVE_TIMEOUT);
416         if (rc) {
417                 dprintk("RPC:       %s: rdma_resolve_route() failed %i\n",
418                         __func__, rc);
419                 goto put;
420         }
421         wait_for_completion_interruptible_timeout(&ia->ri_done,
422                                 msecs_to_jiffies(RDMA_RESOLVE_TIMEOUT) + 1);
423         rc = ia->ri_async_rc;
424         if (rc)
425                 goto put;
426
427         return id;
428 put:
429         module_put(id->device->owner);
430 out:
431         rdma_destroy_id(id);
432         return ERR_PTR(rc);
433 }
434
435 /*
436  * Drain any cq, prior to teardown.
437  */
438 static void
439 rpcrdma_clean_cq(struct ib_cq *cq)
440 {
441         struct ib_wc wc;
442         int count = 0;
443
444         while (1 == ib_poll_cq(cq, 1, &wc))
445                 ++count;
446
447         if (count)
448                 dprintk("RPC:       %s: flushed %d events (last 0x%x)\n",
449                         __func__, count, wc.opcode);
450 }
451
452 /*
453  * Exported functions.
454  */
455
456 /*
457  * Open and initialize an Interface Adapter.
458  *  o initializes fields of struct rpcrdma_ia, including
459  *    interface and provider attributes and protection zone.
460  */
461 int
462 rpcrdma_ia_open(struct rpcrdma_xprt *xprt, struct sockaddr *addr, int memreg)
463 {
464         struct rpcrdma_ia *ia = &xprt->rx_ia;
465         int rc;
466
467         ia->ri_dma_mr = NULL;
468
469         ia->ri_id = rpcrdma_create_id(xprt, ia, addr);
470         if (IS_ERR(ia->ri_id)) {
471                 rc = PTR_ERR(ia->ri_id);
472                 goto out1;
473         }
474         ia->ri_device = ia->ri_id->device;
475
476         ia->ri_pd = ib_alloc_pd(ia->ri_device);
477         if (IS_ERR(ia->ri_pd)) {
478                 rc = PTR_ERR(ia->ri_pd);
479                 dprintk("RPC:       %s: ib_alloc_pd() failed %i\n",
480                         __func__, rc);
481                 goto out2;
482         }
483
484         if (memreg == RPCRDMA_FRMR) {
485                 if (!(ia->ri_device->attrs.device_cap_flags &
486                                 IB_DEVICE_MEM_MGT_EXTENSIONS) ||
487                     (ia->ri_device->attrs.max_fast_reg_page_list_len == 0)) {
488                         dprintk("RPC:       %s: FRMR registration "
489                                 "not supported by HCA\n", __func__);
490                         memreg = RPCRDMA_MTHCAFMR;
491                 }
492         }
493         if (memreg == RPCRDMA_MTHCAFMR) {
494                 if (!ia->ri_device->alloc_fmr) {
495                         dprintk("RPC:       %s: MTHCAFMR registration "
496                                 "not supported by HCA\n", __func__);
497                         rc = -EINVAL;
498                         goto out3;
499                 }
500         }
501
502         switch (memreg) {
503         case RPCRDMA_FRMR:
504                 ia->ri_ops = &rpcrdma_frwr_memreg_ops;
505                 break;
506         case RPCRDMA_ALLPHYSICAL:
507                 ia->ri_ops = &rpcrdma_physical_memreg_ops;
508                 break;
509         case RPCRDMA_MTHCAFMR:
510                 ia->ri_ops = &rpcrdma_fmr_memreg_ops;
511                 break;
512         default:
513                 printk(KERN_ERR "RPC: Unsupported memory "
514                                 "registration mode: %d\n", memreg);
515                 rc = -ENOMEM;
516                 goto out3;
517         }
518         dprintk("RPC:       %s: memory registration strategy is '%s'\n",
519                 __func__, ia->ri_ops->ro_displayname);
520
521         rwlock_init(&ia->ri_qplock);
522         return 0;
523
524 out3:
525         ib_dealloc_pd(ia->ri_pd);
526         ia->ri_pd = NULL;
527 out2:
528         rpcrdma_destroy_id(ia->ri_id);
529         ia->ri_id = NULL;
530 out1:
531         return rc;
532 }
533
534 /*
535  * Clean up/close an IA.
536  *   o if event handles and PD have been initialized, free them.
537  *   o close the IA
538  */
539 void
540 rpcrdma_ia_close(struct rpcrdma_ia *ia)
541 {
542         dprintk("RPC:       %s: entering\n", __func__);
543         if (ia->ri_id != NULL && !IS_ERR(ia->ri_id)) {
544                 if (ia->ri_id->qp)
545                         rdma_destroy_qp(ia->ri_id);
546                 rpcrdma_destroy_id(ia->ri_id);
547                 ia->ri_id = NULL;
548         }
549
550         /* If the pd is still busy, xprtrdma missed freeing a resource */
551         if (ia->ri_pd && !IS_ERR(ia->ri_pd))
552                 ib_dealloc_pd(ia->ri_pd);
553 }
554
555 /*
556  * Create unconnected endpoint.
557  */
558 int
559 rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
560                                 struct rpcrdma_create_data_internal *cdata)
561 {
562         struct ib_cq *sendcq, *recvcq;
563         struct ib_cq_init_attr cq_attr = {};
564         unsigned int max_qp_wr;
565         int rc, err;
566
567         if (ia->ri_device->attrs.max_sge < RPCRDMA_MAX_IOVS) {
568                 dprintk("RPC:       %s: insufficient sge's available\n",
569                         __func__);
570                 return -ENOMEM;
571         }
572
573         if (ia->ri_device->attrs.max_qp_wr <= RPCRDMA_BACKWARD_WRS) {
574                 dprintk("RPC:       %s: insufficient wqe's available\n",
575                         __func__);
576                 return -ENOMEM;
577         }
578         max_qp_wr = ia->ri_device->attrs.max_qp_wr - RPCRDMA_BACKWARD_WRS;
579
580         /* check provider's send/recv wr limits */
581         if (cdata->max_requests > max_qp_wr)
582                 cdata->max_requests = max_qp_wr;
583
584         ep->rep_attr.event_handler = rpcrdma_qp_async_error_upcall;
585         ep->rep_attr.qp_context = ep;
586         ep->rep_attr.srq = NULL;
587         ep->rep_attr.cap.max_send_wr = cdata->max_requests;
588         ep->rep_attr.cap.max_send_wr += RPCRDMA_BACKWARD_WRS;
589         rc = ia->ri_ops->ro_open(ia, ep, cdata);
590         if (rc)
591                 return rc;
592         ep->rep_attr.cap.max_recv_wr = cdata->max_requests;
593         ep->rep_attr.cap.max_recv_wr += RPCRDMA_BACKWARD_WRS;
594         ep->rep_attr.cap.max_send_sge = RPCRDMA_MAX_IOVS;
595         ep->rep_attr.cap.max_recv_sge = 1;
596         ep->rep_attr.cap.max_inline_data = 0;
597         ep->rep_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
598         ep->rep_attr.qp_type = IB_QPT_RC;
599         ep->rep_attr.port_num = ~0;
600
601         dprintk("RPC:       %s: requested max: dtos: send %d recv %d; "
602                 "iovs: send %d recv %d\n",
603                 __func__,
604                 ep->rep_attr.cap.max_send_wr,
605                 ep->rep_attr.cap.max_recv_wr,
606                 ep->rep_attr.cap.max_send_sge,
607                 ep->rep_attr.cap.max_recv_sge);
608
609         /* set trigger for requesting send completion */
610         ep->rep_cqinit = ep->rep_attr.cap.max_send_wr/2 - 1;
611         if (ep->rep_cqinit <= 2)
612                 ep->rep_cqinit = 0;     /* always signal? */
613         INIT_CQCOUNT(ep);
614         init_waitqueue_head(&ep->rep_connect_wait);
615         INIT_DELAYED_WORK(&ep->rep_connect_worker, rpcrdma_connect_worker);
616
617         cq_attr.cqe = ep->rep_attr.cap.max_send_wr + 1;
618         sendcq = ib_create_cq(ia->ri_device, rpcrdma_sendcq_upcall,
619                               rpcrdma_cq_async_error_upcall, NULL, &cq_attr);
620         if (IS_ERR(sendcq)) {
621                 rc = PTR_ERR(sendcq);
622                 dprintk("RPC:       %s: failed to create send CQ: %i\n",
623                         __func__, rc);
624                 goto out1;
625         }
626
627         rc = ib_req_notify_cq(sendcq, IB_CQ_NEXT_COMP);
628         if (rc) {
629                 dprintk("RPC:       %s: ib_req_notify_cq failed: %i\n",
630                         __func__, rc);
631                 goto out2;
632         }
633
634         cq_attr.cqe = ep->rep_attr.cap.max_recv_wr + 1;
635         recvcq = ib_create_cq(ia->ri_device, rpcrdma_recvcq_upcall,
636                               rpcrdma_cq_async_error_upcall, NULL, &cq_attr);
637         if (IS_ERR(recvcq)) {
638                 rc = PTR_ERR(recvcq);
639                 dprintk("RPC:       %s: failed to create recv CQ: %i\n",
640                         __func__, rc);
641                 goto out2;
642         }
643
644         rc = ib_req_notify_cq(recvcq, IB_CQ_NEXT_COMP);
645         if (rc) {
646                 dprintk("RPC:       %s: ib_req_notify_cq failed: %i\n",
647                         __func__, rc);
648                 ib_destroy_cq(recvcq);
649                 goto out2;
650         }
651
652         ep->rep_attr.send_cq = sendcq;
653         ep->rep_attr.recv_cq = recvcq;
654
655         /* Initialize cma parameters */
656
657         /* RPC/RDMA does not use private data */
658         ep->rep_remote_cma.private_data = NULL;
659         ep->rep_remote_cma.private_data_len = 0;
660
661         /* Client offers RDMA Read but does not initiate */
662         ep->rep_remote_cma.initiator_depth = 0;
663         if (ia->ri_device->attrs.max_qp_rd_atom > 32)   /* arbitrary but <= 255 */
664                 ep->rep_remote_cma.responder_resources = 32;
665         else
666                 ep->rep_remote_cma.responder_resources =
667                                                 ia->ri_device->attrs.max_qp_rd_atom;
668
669         ep->rep_remote_cma.retry_count = 7;
670         ep->rep_remote_cma.flow_control = 0;
671         ep->rep_remote_cma.rnr_retry_count = 0;
672
673         return 0;
674
675 out2:
676         err = ib_destroy_cq(sendcq);
677         if (err)
678                 dprintk("RPC:       %s: ib_destroy_cq returned %i\n",
679                         __func__, err);
680 out1:
681         if (ia->ri_dma_mr)
682                 ib_dereg_mr(ia->ri_dma_mr);
683         return rc;
684 }
685
686 /*
687  * rpcrdma_ep_destroy
688  *
689  * Disconnect and destroy endpoint. After this, the only
690  * valid operations on the ep are to free it (if dynamically
691  * allocated) or re-create it.
692  */
693 void
694 rpcrdma_ep_destroy(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
695 {
696         int rc;
697
698         dprintk("RPC:       %s: entering, connected is %d\n",
699                 __func__, ep->rep_connected);
700
701         cancel_delayed_work_sync(&ep->rep_connect_worker);
702
703         if (ia->ri_id->qp)
704                 rpcrdma_ep_disconnect(ep, ia);
705
706         rpcrdma_clean_cq(ep->rep_attr.recv_cq);
707         rpcrdma_clean_cq(ep->rep_attr.send_cq);
708
709         if (ia->ri_id->qp) {
710                 rdma_destroy_qp(ia->ri_id);
711                 ia->ri_id->qp = NULL;
712         }
713
714         rc = ib_destroy_cq(ep->rep_attr.recv_cq);
715         if (rc)
716                 dprintk("RPC:       %s: ib_destroy_cq returned %i\n",
717                         __func__, rc);
718
719         rc = ib_destroy_cq(ep->rep_attr.send_cq);
720         if (rc)
721                 dprintk("RPC:       %s: ib_destroy_cq returned %i\n",
722                         __func__, rc);
723
724         if (ia->ri_dma_mr) {
725                 rc = ib_dereg_mr(ia->ri_dma_mr);
726                 dprintk("RPC:       %s: ib_dereg_mr returned %i\n",
727                         __func__, rc);
728         }
729 }
730
731 /*
732  * Connect unconnected endpoint.
733  */
734 int
735 rpcrdma_ep_connect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
736 {
737         struct rdma_cm_id *id, *old;
738         int rc = 0;
739         int retry_count = 0;
740
741         if (ep->rep_connected != 0) {
742                 struct rpcrdma_xprt *xprt;
743 retry:
744                 dprintk("RPC:       %s: reconnecting...\n", __func__);
745
746                 rpcrdma_ep_disconnect(ep, ia);
747                 rpcrdma_flush_cqs(ep);
748
749                 xprt = container_of(ia, struct rpcrdma_xprt, rx_ia);
750                 id = rpcrdma_create_id(xprt, ia,
751                                 (struct sockaddr *)&xprt->rx_data.addr);
752                 if (IS_ERR(id)) {
753                         rc = -EHOSTUNREACH;
754                         goto out;
755                 }
756                 /* TEMP TEMP TEMP - fail if new device:
757                  * Deregister/remarshal *all* requests!
758                  * Close and recreate adapter, pd, etc!
759                  * Re-determine all attributes still sane!
760                  * More stuff I haven't thought of!
761                  * Rrrgh!
762                  */
763                 if (ia->ri_device != id->device) {
764                         printk("RPC:       %s: can't reconnect on "
765                                 "different device!\n", __func__);
766                         rpcrdma_destroy_id(id);
767                         rc = -ENETUNREACH;
768                         goto out;
769                 }
770                 /* END TEMP */
771                 rc = rdma_create_qp(id, ia->ri_pd, &ep->rep_attr);
772                 if (rc) {
773                         dprintk("RPC:       %s: rdma_create_qp failed %i\n",
774                                 __func__, rc);
775                         rpcrdma_destroy_id(id);
776                         rc = -ENETUNREACH;
777                         goto out;
778                 }
779
780                 write_lock(&ia->ri_qplock);
781                 old = ia->ri_id;
782                 ia->ri_id = id;
783                 write_unlock(&ia->ri_qplock);
784
785                 rdma_destroy_qp(old);
786                 rpcrdma_destroy_id(old);
787         } else {
788                 dprintk("RPC:       %s: connecting...\n", __func__);
789                 rc = rdma_create_qp(ia->ri_id, ia->ri_pd, &ep->rep_attr);
790                 if (rc) {
791                         dprintk("RPC:       %s: rdma_create_qp failed %i\n",
792                                 __func__, rc);
793                         /* do not update ep->rep_connected */
794                         return -ENETUNREACH;
795                 }
796         }
797
798         ep->rep_connected = 0;
799
800         rc = rdma_connect(ia->ri_id, &ep->rep_remote_cma);
801         if (rc) {
802                 dprintk("RPC:       %s: rdma_connect() failed with %i\n",
803                                 __func__, rc);
804                 goto out;
805         }
806
807         wait_event_interruptible(ep->rep_connect_wait, ep->rep_connected != 0);
808
809         /*
810          * Check state. A non-peer reject indicates no listener
811          * (ECONNREFUSED), which may be a transient state. All
812          * others indicate a transport condition which has already
813          * undergone a best-effort.
814          */
815         if (ep->rep_connected == -ECONNREFUSED &&
816             ++retry_count <= RDMA_CONNECT_RETRY_MAX) {
817                 dprintk("RPC:       %s: non-peer_reject, retry\n", __func__);
818                 goto retry;
819         }
820         if (ep->rep_connected <= 0) {
821                 /* Sometimes, the only way to reliably connect to remote
822                  * CMs is to use same nonzero values for ORD and IRD. */
823                 if (retry_count++ <= RDMA_CONNECT_RETRY_MAX + 1 &&
824                     (ep->rep_remote_cma.responder_resources == 0 ||
825                      ep->rep_remote_cma.initiator_depth !=
826                                 ep->rep_remote_cma.responder_resources)) {
827                         if (ep->rep_remote_cma.responder_resources == 0)
828                                 ep->rep_remote_cma.responder_resources = 1;
829                         ep->rep_remote_cma.initiator_depth =
830                                 ep->rep_remote_cma.responder_resources;
831                         goto retry;
832                 }
833                 rc = ep->rep_connected;
834         } else {
835                 struct rpcrdma_xprt *r_xprt;
836                 unsigned int extras;
837
838                 dprintk("RPC:       %s: connected\n", __func__);
839
840                 r_xprt = container_of(ia, struct rpcrdma_xprt, rx_ia);
841                 extras = r_xprt->rx_buf.rb_bc_srv_max_requests;
842
843                 if (extras) {
844                         rc = rpcrdma_ep_post_extra_recv(r_xprt, extras);
845                         if (rc) {
846                                 pr_warn("%s: rpcrdma_ep_post_extra_recv: %i\n",
847                                         __func__, rc);
848                                 rc = 0;
849                         }
850                 }
851         }
852
853 out:
854         if (rc)
855                 ep->rep_connected = rc;
856         return rc;
857 }
858
859 /*
860  * rpcrdma_ep_disconnect
861  *
862  * This is separate from destroy to facilitate the ability
863  * to reconnect without recreating the endpoint.
864  *
865  * This call is not reentrant, and must not be made in parallel
866  * on the same endpoint.
867  */
868 void
869 rpcrdma_ep_disconnect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
870 {
871         int rc;
872
873         rpcrdma_flush_cqs(ep);
874         rc = rdma_disconnect(ia->ri_id);
875         if (!rc) {
876                 /* returns without wait if not connected */
877                 wait_event_interruptible(ep->rep_connect_wait,
878                                                         ep->rep_connected != 1);
879                 dprintk("RPC:       %s: after wait, %sconnected\n", __func__,
880                         (ep->rep_connected == 1) ? "still " : "dis");
881         } else {
882                 dprintk("RPC:       %s: rdma_disconnect %i\n", __func__, rc);
883                 ep->rep_connected = rc;
884         }
885 }
886
887 struct rpcrdma_req *
888 rpcrdma_create_req(struct rpcrdma_xprt *r_xprt)
889 {
890         struct rpcrdma_buffer *buffer = &r_xprt->rx_buf;
891         struct rpcrdma_req *req;
892
893         req = kzalloc(sizeof(*req), GFP_KERNEL);
894         if (req == NULL)
895                 return ERR_PTR(-ENOMEM);
896
897         INIT_LIST_HEAD(&req->rl_free);
898         spin_lock(&buffer->rb_reqslock);
899         list_add(&req->rl_all, &buffer->rb_allreqs);
900         spin_unlock(&buffer->rb_reqslock);
901         req->rl_buffer = &r_xprt->rx_buf;
902         return req;
903 }
904
905 struct rpcrdma_rep *
906 rpcrdma_create_rep(struct rpcrdma_xprt *r_xprt)
907 {
908         struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data;
909         struct rpcrdma_ia *ia = &r_xprt->rx_ia;
910         struct rpcrdma_rep *rep;
911         int rc;
912
913         rc = -ENOMEM;
914         rep = kzalloc(sizeof(*rep), GFP_KERNEL);
915         if (rep == NULL)
916                 goto out;
917
918         rep->rr_rdmabuf = rpcrdma_alloc_regbuf(ia, cdata->inline_rsize,
919                                                GFP_KERNEL);
920         if (IS_ERR(rep->rr_rdmabuf)) {
921                 rc = PTR_ERR(rep->rr_rdmabuf);
922                 goto out_free;
923         }
924
925         rep->rr_device = ia->ri_device;
926         rep->rr_rxprt = r_xprt;
927         INIT_WORK(&rep->rr_work, rpcrdma_receive_worker);
928         return rep;
929
930 out_free:
931         kfree(rep);
932 out:
933         return ERR_PTR(rc);
934 }
935
936 int
937 rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt)
938 {
939         struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
940         struct rpcrdma_ia *ia = &r_xprt->rx_ia;
941         int i, rc;
942
943         buf->rb_max_requests = r_xprt->rx_data.max_requests;
944         buf->rb_bc_srv_max_requests = 0;
945         spin_lock_init(&buf->rb_lock);
946
947         rc = ia->ri_ops->ro_init(r_xprt);
948         if (rc)
949                 goto out;
950
951         INIT_LIST_HEAD(&buf->rb_send_bufs);
952         INIT_LIST_HEAD(&buf->rb_allreqs);
953         spin_lock_init(&buf->rb_reqslock);
954         for (i = 0; i < buf->rb_max_requests; i++) {
955                 struct rpcrdma_req *req;
956
957                 req = rpcrdma_create_req(r_xprt);
958                 if (IS_ERR(req)) {
959                         dprintk("RPC:       %s: request buffer %d alloc"
960                                 " failed\n", __func__, i);
961                         rc = PTR_ERR(req);
962                         goto out;
963                 }
964                 req->rl_backchannel = false;
965                 list_add(&req->rl_free, &buf->rb_send_bufs);
966         }
967
968         INIT_LIST_HEAD(&buf->rb_recv_bufs);
969         for (i = 0; i < buf->rb_max_requests + 2; i++) {
970                 struct rpcrdma_rep *rep;
971
972                 rep = rpcrdma_create_rep(r_xprt);
973                 if (IS_ERR(rep)) {
974                         dprintk("RPC:       %s: reply buffer %d alloc failed\n",
975                                 __func__, i);
976                         rc = PTR_ERR(rep);
977                         goto out;
978                 }
979                 list_add(&rep->rr_list, &buf->rb_recv_bufs);
980         }
981
982         return 0;
983 out:
984         rpcrdma_buffer_destroy(buf);
985         return rc;
986 }
987
988 static struct rpcrdma_req *
989 rpcrdma_buffer_get_req_locked(struct rpcrdma_buffer *buf)
990 {
991         struct rpcrdma_req *req;
992
993         req = list_first_entry(&buf->rb_send_bufs,
994                                struct rpcrdma_req, rl_free);
995         list_del(&req->rl_free);
996         return req;
997 }
998
999 static struct rpcrdma_rep *
1000 rpcrdma_buffer_get_rep_locked(struct rpcrdma_buffer *buf)
1001 {
1002         struct rpcrdma_rep *rep;
1003
1004         rep = list_first_entry(&buf->rb_recv_bufs,
1005                                struct rpcrdma_rep, rr_list);
1006         list_del(&rep->rr_list);
1007         return rep;
1008 }
1009
1010 static void
1011 rpcrdma_destroy_rep(struct rpcrdma_ia *ia, struct rpcrdma_rep *rep)
1012 {
1013         rpcrdma_free_regbuf(ia, rep->rr_rdmabuf);
1014         kfree(rep);
1015 }
1016
1017 void
1018 rpcrdma_destroy_req(struct rpcrdma_ia *ia, struct rpcrdma_req *req)
1019 {
1020         rpcrdma_free_regbuf(ia, req->rl_sendbuf);
1021         rpcrdma_free_regbuf(ia, req->rl_rdmabuf);
1022         kfree(req);
1023 }
1024
1025 void
1026 rpcrdma_buffer_destroy(struct rpcrdma_buffer *buf)
1027 {
1028         struct rpcrdma_ia *ia = rdmab_to_ia(buf);
1029
1030         while (!list_empty(&buf->rb_recv_bufs)) {
1031                 struct rpcrdma_rep *rep;
1032
1033                 rep = rpcrdma_buffer_get_rep_locked(buf);
1034                 rpcrdma_destroy_rep(ia, rep);
1035         }
1036
1037         spin_lock(&buf->rb_reqslock);
1038         while (!list_empty(&buf->rb_allreqs)) {
1039                 struct rpcrdma_req *req;
1040
1041                 req = list_first_entry(&buf->rb_allreqs,
1042                                        struct rpcrdma_req, rl_all);
1043                 list_del(&req->rl_all);
1044
1045                 spin_unlock(&buf->rb_reqslock);
1046                 rpcrdma_destroy_req(ia, req);
1047                 spin_lock(&buf->rb_reqslock);
1048         }
1049         spin_unlock(&buf->rb_reqslock);
1050
1051         ia->ri_ops->ro_destroy(buf);
1052 }
1053
1054 struct rpcrdma_mw *
1055 rpcrdma_get_mw(struct rpcrdma_xprt *r_xprt)
1056 {
1057         struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
1058         struct rpcrdma_mw *mw = NULL;
1059
1060         spin_lock(&buf->rb_mwlock);
1061         if (!list_empty(&buf->rb_mws)) {
1062                 mw = list_first_entry(&buf->rb_mws,
1063                                       struct rpcrdma_mw, mw_list);
1064                 list_del_init(&mw->mw_list);
1065         }
1066         spin_unlock(&buf->rb_mwlock);
1067
1068         if (!mw)
1069                 pr_err("RPC:       %s: no MWs available\n", __func__);
1070         return mw;
1071 }
1072
1073 void
1074 rpcrdma_put_mw(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mw *mw)
1075 {
1076         struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
1077
1078         spin_lock(&buf->rb_mwlock);
1079         list_add_tail(&mw->mw_list, &buf->rb_mws);
1080         spin_unlock(&buf->rb_mwlock);
1081 }
1082
1083 /*
1084  * Get a set of request/reply buffers.
1085  *
1086  * Reply buffer (if available) is attached to send buffer upon return.
1087  */
1088 struct rpcrdma_req *
1089 rpcrdma_buffer_get(struct rpcrdma_buffer *buffers)
1090 {
1091         struct rpcrdma_req *req;
1092
1093         spin_lock(&buffers->rb_lock);
1094         if (list_empty(&buffers->rb_send_bufs))
1095                 goto out_reqbuf;
1096         req = rpcrdma_buffer_get_req_locked(buffers);
1097         if (list_empty(&buffers->rb_recv_bufs))
1098                 goto out_repbuf;
1099         req->rl_reply = rpcrdma_buffer_get_rep_locked(buffers);
1100         spin_unlock(&buffers->rb_lock);
1101         return req;
1102
1103 out_reqbuf:
1104         spin_unlock(&buffers->rb_lock);
1105         pr_warn("RPC:       %s: out of request buffers\n", __func__);
1106         return NULL;
1107 out_repbuf:
1108         spin_unlock(&buffers->rb_lock);
1109         pr_warn("RPC:       %s: out of reply buffers\n", __func__);
1110         req->rl_reply = NULL;
1111         return req;
1112 }
1113
1114 /*
1115  * Put request/reply buffers back into pool.
1116  * Pre-decrement counter/array index.
1117  */
1118 void
1119 rpcrdma_buffer_put(struct rpcrdma_req *req)
1120 {
1121         struct rpcrdma_buffer *buffers = req->rl_buffer;
1122         struct rpcrdma_rep *rep = req->rl_reply;
1123
1124         req->rl_niovs = 0;
1125         req->rl_reply = NULL;
1126
1127         spin_lock(&buffers->rb_lock);
1128         list_add_tail(&req->rl_free, &buffers->rb_send_bufs);
1129         if (rep)
1130                 list_add_tail(&rep->rr_list, &buffers->rb_recv_bufs);
1131         spin_unlock(&buffers->rb_lock);
1132 }
1133
1134 /*
1135  * Recover reply buffers from pool.
1136  * This happens when recovering from disconnect.
1137  */
1138 void
1139 rpcrdma_recv_buffer_get(struct rpcrdma_req *req)
1140 {
1141         struct rpcrdma_buffer *buffers = req->rl_buffer;
1142
1143         spin_lock(&buffers->rb_lock);
1144         if (!list_empty(&buffers->rb_recv_bufs))
1145                 req->rl_reply = rpcrdma_buffer_get_rep_locked(buffers);
1146         spin_unlock(&buffers->rb_lock);
1147 }
1148
1149 /*
1150  * Put reply buffers back into pool when not attached to
1151  * request. This happens in error conditions.
1152  */
1153 void
1154 rpcrdma_recv_buffer_put(struct rpcrdma_rep *rep)
1155 {
1156         struct rpcrdma_buffer *buffers = &rep->rr_rxprt->rx_buf;
1157
1158         spin_lock(&buffers->rb_lock);
1159         list_add_tail(&rep->rr_list, &buffers->rb_recv_bufs);
1160         spin_unlock(&buffers->rb_lock);
1161 }
1162
1163 /*
1164  * Wrappers for internal-use kmalloc memory registration, used by buffer code.
1165  */
1166
1167 void
1168 rpcrdma_mapping_error(struct rpcrdma_mr_seg *seg)
1169 {
1170         dprintk("RPC:       map_one: offset %p iova %llx len %zu\n",
1171                 seg->mr_offset,
1172                 (unsigned long long)seg->mr_dma, seg->mr_dmalen);
1173 }
1174
1175 /**
1176  * rpcrdma_alloc_regbuf - kmalloc and register memory for SEND/RECV buffers
1177  * @ia: controlling rpcrdma_ia
1178  * @size: size of buffer to be allocated, in bytes
1179  * @flags: GFP flags
1180  *
1181  * Returns pointer to private header of an area of internally
1182  * registered memory, or an ERR_PTR. The registered buffer follows
1183  * the end of the private header.
1184  *
1185  * xprtrdma uses a regbuf for posting an outgoing RDMA SEND, or for
1186  * receiving the payload of RDMA RECV operations. regbufs are not
1187  * used for RDMA READ/WRITE operations, thus are registered only for
1188  * LOCAL access.
1189  */
1190 struct rpcrdma_regbuf *
1191 rpcrdma_alloc_regbuf(struct rpcrdma_ia *ia, size_t size, gfp_t flags)
1192 {
1193         struct rpcrdma_regbuf *rb;
1194         struct ib_sge *iov;
1195
1196         rb = kmalloc(sizeof(*rb) + size, flags);
1197         if (rb == NULL)
1198                 goto out;
1199
1200         iov = &rb->rg_iov;
1201         iov->addr = ib_dma_map_single(ia->ri_device,
1202                                       (void *)rb->rg_base, size,
1203                                       DMA_BIDIRECTIONAL);
1204         if (ib_dma_mapping_error(ia->ri_device, iov->addr))
1205                 goto out_free;
1206
1207         iov->length = size;
1208         iov->lkey = ia->ri_pd->local_dma_lkey;
1209         rb->rg_size = size;
1210         rb->rg_owner = NULL;
1211         return rb;
1212
1213 out_free:
1214         kfree(rb);
1215 out:
1216         return ERR_PTR(-ENOMEM);
1217 }
1218
1219 /**
1220  * rpcrdma_free_regbuf - deregister and free registered buffer
1221  * @ia: controlling rpcrdma_ia
1222  * @rb: regbuf to be deregistered and freed
1223  */
1224 void
1225 rpcrdma_free_regbuf(struct rpcrdma_ia *ia, struct rpcrdma_regbuf *rb)
1226 {
1227         struct ib_sge *iov;
1228
1229         if (!rb)
1230                 return;
1231
1232         iov = &rb->rg_iov;
1233         ib_dma_unmap_single(ia->ri_device,
1234                             iov->addr, iov->length, DMA_BIDIRECTIONAL);
1235         kfree(rb);
1236 }
1237
1238 /*
1239  * Prepost any receive buffer, then post send.
1240  *
1241  * Receive buffer is donated to hardware, reclaimed upon recv completion.
1242  */
1243 int
1244 rpcrdma_ep_post(struct rpcrdma_ia *ia,
1245                 struct rpcrdma_ep *ep,
1246                 struct rpcrdma_req *req)
1247 {
1248         struct ib_device *device = ia->ri_device;
1249         struct ib_send_wr send_wr, *send_wr_fail;
1250         struct rpcrdma_rep *rep = req->rl_reply;
1251         struct ib_sge *iov = req->rl_send_iov;
1252         int i, rc;
1253
1254         if (rep) {
1255                 rc = rpcrdma_ep_post_recv(ia, ep, rep);
1256                 if (rc)
1257                         goto out;
1258                 req->rl_reply = NULL;
1259         }
1260
1261         send_wr.next = NULL;
1262         send_wr.wr_id = RPCRDMA_IGNORE_COMPLETION;
1263         send_wr.sg_list = iov;
1264         send_wr.num_sge = req->rl_niovs;
1265         send_wr.opcode = IB_WR_SEND;
1266
1267         for (i = 0; i < send_wr.num_sge; i++)
1268                 ib_dma_sync_single_for_device(device, iov[i].addr,
1269                                               iov[i].length, DMA_TO_DEVICE);
1270         dprintk("RPC:       %s: posting %d s/g entries\n",
1271                 __func__, send_wr.num_sge);
1272
1273         if (DECR_CQCOUNT(ep) > 0)
1274                 send_wr.send_flags = 0;
1275         else { /* Provider must take a send completion every now and then */
1276                 INIT_CQCOUNT(ep);
1277                 send_wr.send_flags = IB_SEND_SIGNALED;
1278         }
1279
1280         rc = ib_post_send(ia->ri_id->qp, &send_wr, &send_wr_fail);
1281         if (rc)
1282                 dprintk("RPC:       %s: ib_post_send returned %i\n", __func__,
1283                         rc);
1284 out:
1285         return rc;
1286 }
1287
1288 /*
1289  * (Re)post a receive buffer.
1290  */
1291 int
1292 rpcrdma_ep_post_recv(struct rpcrdma_ia *ia,
1293                      struct rpcrdma_ep *ep,
1294                      struct rpcrdma_rep *rep)
1295 {
1296         struct ib_recv_wr recv_wr, *recv_wr_fail;
1297         int rc;
1298
1299         recv_wr.next = NULL;
1300         recv_wr.wr_id = (u64) (unsigned long) rep;
1301         recv_wr.sg_list = &rep->rr_rdmabuf->rg_iov;
1302         recv_wr.num_sge = 1;
1303
1304         ib_dma_sync_single_for_cpu(ia->ri_device,
1305                                    rdmab_addr(rep->rr_rdmabuf),
1306                                    rdmab_length(rep->rr_rdmabuf),
1307                                    DMA_BIDIRECTIONAL);
1308
1309         rc = ib_post_recv(ia->ri_id->qp, &recv_wr, &recv_wr_fail);
1310
1311         if (rc)
1312                 dprintk("RPC:       %s: ib_post_recv returned %i\n", __func__,
1313                         rc);
1314         return rc;
1315 }
1316
1317 /**
1318  * rpcrdma_ep_post_extra_recv - Post buffers for incoming backchannel requests
1319  * @r_xprt: transport associated with these backchannel resources
1320  * @min_reqs: minimum number of incoming requests expected
1321  *
1322  * Returns zero if all requested buffers were posted, or a negative errno.
1323  */
1324 int
1325 rpcrdma_ep_post_extra_recv(struct rpcrdma_xprt *r_xprt, unsigned int count)
1326 {
1327         struct rpcrdma_buffer *buffers = &r_xprt->rx_buf;
1328         struct rpcrdma_ia *ia = &r_xprt->rx_ia;
1329         struct rpcrdma_ep *ep = &r_xprt->rx_ep;
1330         struct rpcrdma_rep *rep;
1331         int rc;
1332
1333         while (count--) {
1334                 spin_lock(&buffers->rb_lock);
1335                 if (list_empty(&buffers->rb_recv_bufs))
1336                         goto out_reqbuf;
1337                 rep = rpcrdma_buffer_get_rep_locked(buffers);
1338                 spin_unlock(&buffers->rb_lock);
1339
1340                 rc = rpcrdma_ep_post_recv(ia, ep, rep);
1341                 if (rc)
1342                         goto out_rc;
1343         }
1344
1345         return 0;
1346
1347 out_reqbuf:
1348         spin_unlock(&buffers->rb_lock);
1349         pr_warn("%s: no extra receive buffers\n", __func__);
1350         return -ENOMEM;
1351
1352 out_rc:
1353         rpcrdma_recv_buffer_put(rep);
1354         return rc;
1355 }
1356
1357 /* How many chunk list items fit within our inline buffers?
1358  */
1359 unsigned int
1360 rpcrdma_max_segments(struct rpcrdma_xprt *r_xprt)
1361 {
1362         struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data;
1363         int bytes, segments;
1364
1365         bytes = min_t(unsigned int, cdata->inline_wsize, cdata->inline_rsize);
1366         bytes -= RPCRDMA_HDRLEN_MIN;
1367         if (bytes < sizeof(struct rpcrdma_segment) * 2) {
1368                 pr_warn("RPC:       %s: inline threshold too small\n",
1369                         __func__);
1370                 return 0;
1371         }
1372
1373         segments = 1 << (fls(bytes / sizeof(struct rpcrdma_segment)) - 1);
1374         dprintk("RPC:       %s: max chunk list size = %d segments\n",
1375                 __func__, segments);
1376         return segments;
1377 }