Merge tag 'auxdisplay-for-linus-v5.0-rc7' of git://github.com/ojeda/linux
[muen/linux.git] / net / sunrpc / xprtrdma / verbs.c
1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
2 /*
3  * Copyright (c) 2014-2017 Oracle.  All rights reserved.
4  * Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
5  *
6  * This software is available to you under a choice of one of two
7  * licenses.  You may choose to be licensed under the terms of the GNU
8  * General Public License (GPL) Version 2, available from the file
9  * COPYING in the main directory of this source tree, or the BSD-type
10  * license below:
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  *
16  *      Redistributions of source code must retain the above copyright
17  *      notice, this list of conditions and the following disclaimer.
18  *
19  *      Redistributions in binary form must reproduce the above
20  *      copyright notice, this list of conditions and the following
21  *      disclaimer in the documentation and/or other materials provided
22  *      with the distribution.
23  *
24  *      Neither the name of the Network Appliance, Inc. nor the names of
25  *      its contributors may be used to endorse or promote products
26  *      derived from this software without specific prior written
27  *      permission.
28  *
29  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
30  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
31  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
32  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
33  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
34  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
35  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
39  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40  */
41
42 /*
43  * verbs.c
44  *
45  * Encapsulates the major functions managing:
46  *  o adapters
47  *  o endpoints
48  *  o connections
49  *  o buffer memory
50  */
51
52 #include <linux/interrupt.h>
53 #include <linux/slab.h>
54 #include <linux/sunrpc/addr.h>
55 #include <linux/sunrpc/svc_rdma.h>
56
57 #include <asm-generic/barrier.h>
58 #include <asm/bitops.h>
59
60 #include <rdma/ib_cm.h>
61
62 #include "xprt_rdma.h"
63 #include <trace/events/rpcrdma.h>
64
65 /*
66  * Globals/Macros
67  */
68
69 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
70 # define RPCDBG_FACILITY        RPCDBG_TRANS
71 #endif
72
73 /*
74  * internal functions
75  */
76 static void rpcrdma_sendctx_put_locked(struct rpcrdma_sendctx *sc);
77 static void rpcrdma_mrs_create(struct rpcrdma_xprt *r_xprt);
78 static void rpcrdma_mrs_destroy(struct rpcrdma_buffer *buf);
79 static int rpcrdma_create_rep(struct rpcrdma_xprt *r_xprt, bool temp);
80 static void rpcrdma_dma_unmap_regbuf(struct rpcrdma_regbuf *rb);
81 static void rpcrdma_post_recvs(struct rpcrdma_xprt *r_xprt, bool temp);
82
83 /* Wait for outstanding transport work to finish.
84  */
85 static void rpcrdma_xprt_drain(struct rpcrdma_xprt *r_xprt)
86 {
87         struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
88         struct rpcrdma_ia *ia = &r_xprt->rx_ia;
89
90         /* Flush Receives, then wait for deferred Reply work
91          * to complete.
92          */
93         ib_drain_qp(ia->ri_id->qp);
94         drain_workqueue(buf->rb_completion_wq);
95
96         /* Deferred Reply processing might have scheduled
97          * local invalidations.
98          */
99         ib_drain_sq(ia->ri_id->qp);
100 }
101
102 /**
103  * rpcrdma_qp_event_handler - Handle one QP event (error notification)
104  * @event: details of the event
105  * @context: ep that owns QP where event occurred
106  *
107  * Called from the RDMA provider (device driver) possibly in an interrupt
108  * context.
109  */
110 static void
111 rpcrdma_qp_event_handler(struct ib_event *event, void *context)
112 {
113         struct rpcrdma_ep *ep = context;
114         struct rpcrdma_xprt *r_xprt = container_of(ep, struct rpcrdma_xprt,
115                                                    rx_ep);
116
117         trace_xprtrdma_qp_event(r_xprt, event);
118 }
119
120 /**
121  * rpcrdma_wc_send - Invoked by RDMA provider for each polled Send WC
122  * @cq: completion queue (ignored)
123  * @wc: completed WR
124  *
125  */
126 static void
127 rpcrdma_wc_send(struct ib_cq *cq, struct ib_wc *wc)
128 {
129         struct ib_cqe *cqe = wc->wr_cqe;
130         struct rpcrdma_sendctx *sc =
131                 container_of(cqe, struct rpcrdma_sendctx, sc_cqe);
132
133         /* WARNING: Only wr_cqe and status are reliable at this point */
134         trace_xprtrdma_wc_send(sc, wc);
135         if (wc->status != IB_WC_SUCCESS && wc->status != IB_WC_WR_FLUSH_ERR)
136                 pr_err("rpcrdma: Send: %s (%u/0x%x)\n",
137                        ib_wc_status_msg(wc->status),
138                        wc->status, wc->vendor_err);
139
140         rpcrdma_sendctx_put_locked(sc);
141 }
142
143 /**
144  * rpcrdma_wc_receive - Invoked by RDMA provider for each polled Receive WC
145  * @cq: completion queue (ignored)
146  * @wc: completed WR
147  *
148  */
149 static void
150 rpcrdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc)
151 {
152         struct ib_cqe *cqe = wc->wr_cqe;
153         struct rpcrdma_rep *rep = container_of(cqe, struct rpcrdma_rep,
154                                                rr_cqe);
155         struct rpcrdma_xprt *r_xprt = rep->rr_rxprt;
156
157         /* WARNING: Only wr_cqe and status are reliable at this point */
158         trace_xprtrdma_wc_receive(wc);
159         --r_xprt->rx_ep.rep_receive_count;
160         if (wc->status != IB_WC_SUCCESS)
161                 goto out_flushed;
162
163         /* status == SUCCESS means all fields in wc are trustworthy */
164         rpcrdma_set_xdrlen(&rep->rr_hdrbuf, wc->byte_len);
165         rep->rr_wc_flags = wc->wc_flags;
166         rep->rr_inv_rkey = wc->ex.invalidate_rkey;
167
168         ib_dma_sync_single_for_cpu(rdmab_device(rep->rr_rdmabuf),
169                                    rdmab_addr(rep->rr_rdmabuf),
170                                    wc->byte_len, DMA_FROM_DEVICE);
171
172         rpcrdma_post_recvs(r_xprt, false);
173         rpcrdma_reply_handler(rep);
174         return;
175
176 out_flushed:
177         if (wc->status != IB_WC_WR_FLUSH_ERR)
178                 pr_err("rpcrdma: Recv: %s (%u/0x%x)\n",
179                        ib_wc_status_msg(wc->status),
180                        wc->status, wc->vendor_err);
181         rpcrdma_recv_buffer_put(rep);
182 }
183
184 static void
185 rpcrdma_update_connect_private(struct rpcrdma_xprt *r_xprt,
186                                struct rdma_conn_param *param)
187 {
188         struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data;
189         const struct rpcrdma_connect_private *pmsg = param->private_data;
190         unsigned int rsize, wsize;
191
192         /* Default settings for RPC-over-RDMA Version One */
193         r_xprt->rx_ia.ri_implicit_roundup = xprt_rdma_pad_optimize;
194         rsize = RPCRDMA_V1_DEF_INLINE_SIZE;
195         wsize = RPCRDMA_V1_DEF_INLINE_SIZE;
196
197         if (pmsg &&
198             pmsg->cp_magic == rpcrdma_cmp_magic &&
199             pmsg->cp_version == RPCRDMA_CMP_VERSION) {
200                 r_xprt->rx_ia.ri_implicit_roundup = true;
201                 rsize = rpcrdma_decode_buffer_size(pmsg->cp_send_size);
202                 wsize = rpcrdma_decode_buffer_size(pmsg->cp_recv_size);
203         }
204
205         if (rsize < cdata->inline_rsize)
206                 cdata->inline_rsize = rsize;
207         if (wsize < cdata->inline_wsize)
208                 cdata->inline_wsize = wsize;
209         dprintk("RPC:       %s: max send %u, max recv %u\n",
210                 __func__, cdata->inline_wsize, cdata->inline_rsize);
211         rpcrdma_set_max_header_sizes(r_xprt);
212 }
213
214 /**
215  * rpcrdma_cm_event_handler - Handle RDMA CM events
216  * @id: rdma_cm_id on which an event has occurred
217  * @event: details of the event
218  *
219  * Called with @id's mutex held. Returns 1 if caller should
220  * destroy @id, otherwise 0.
221  */
222 static int
223 rpcrdma_cm_event_handler(struct rdma_cm_id *id, struct rdma_cm_event *event)
224 {
225         struct rpcrdma_xprt *r_xprt = id->context;
226         struct rpcrdma_ia *ia = &r_xprt->rx_ia;
227         struct rpcrdma_ep *ep = &r_xprt->rx_ep;
228         struct rpc_xprt *xprt = &r_xprt->rx_xprt;
229
230         might_sleep();
231
232         trace_xprtrdma_cm_event(r_xprt, event);
233         switch (event->event) {
234         case RDMA_CM_EVENT_ADDR_RESOLVED:
235         case RDMA_CM_EVENT_ROUTE_RESOLVED:
236                 ia->ri_async_rc = 0;
237                 complete(&ia->ri_done);
238                 return 0;
239         case RDMA_CM_EVENT_ADDR_ERROR:
240                 ia->ri_async_rc = -EPROTO;
241                 complete(&ia->ri_done);
242                 return 0;
243         case RDMA_CM_EVENT_ROUTE_ERROR:
244                 ia->ri_async_rc = -ENETUNREACH;
245                 complete(&ia->ri_done);
246                 return 0;
247         case RDMA_CM_EVENT_DEVICE_REMOVAL:
248 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
249                 pr_info("rpcrdma: removing device %s for %s:%s\n",
250                         ia->ri_device->name,
251                         rpcrdma_addrstr(r_xprt), rpcrdma_portstr(r_xprt));
252 #endif
253                 set_bit(RPCRDMA_IAF_REMOVING, &ia->ri_flags);
254                 ep->rep_connected = -ENODEV;
255                 xprt_force_disconnect(xprt);
256                 wait_for_completion(&ia->ri_remove_done);
257
258                 ia->ri_id = NULL;
259                 ia->ri_device = NULL;
260                 /* Return 1 to ensure the core destroys the id. */
261                 return 1;
262         case RDMA_CM_EVENT_ESTABLISHED:
263                 ++xprt->connect_cookie;
264                 ep->rep_connected = 1;
265                 rpcrdma_update_connect_private(r_xprt, &event->param.conn);
266                 wake_up_all(&ep->rep_connect_wait);
267                 break;
268         case RDMA_CM_EVENT_CONNECT_ERROR:
269                 ep->rep_connected = -ENOTCONN;
270                 goto disconnected;
271         case RDMA_CM_EVENT_UNREACHABLE:
272                 ep->rep_connected = -ENETUNREACH;
273                 goto disconnected;
274         case RDMA_CM_EVENT_REJECTED:
275                 dprintk("rpcrdma: connection to %s:%s rejected: %s\n",
276                         rpcrdma_addrstr(r_xprt), rpcrdma_portstr(r_xprt),
277                         rdma_reject_msg(id, event->status));
278                 ep->rep_connected = -ECONNREFUSED;
279                 if (event->status == IB_CM_REJ_STALE_CONN)
280                         ep->rep_connected = -EAGAIN;
281                 goto disconnected;
282         case RDMA_CM_EVENT_DISCONNECTED:
283                 ep->rep_connected = -ECONNABORTED;
284 disconnected:
285                 xprt_force_disconnect(xprt);
286                 wake_up_all(&ep->rep_connect_wait);
287                 break;
288         default:
289                 break;
290         }
291
292         dprintk("RPC:       %s: %s:%s on %s/frwr: %s\n", __func__,
293                 rpcrdma_addrstr(r_xprt), rpcrdma_portstr(r_xprt),
294                 ia->ri_device->name, rdma_event_msg(event->event));
295         return 0;
296 }
297
298 static struct rdma_cm_id *
299 rpcrdma_create_id(struct rpcrdma_xprt *xprt, struct rpcrdma_ia *ia)
300 {
301         unsigned long wtimeout = msecs_to_jiffies(RDMA_RESOLVE_TIMEOUT) + 1;
302         struct rdma_cm_id *id;
303         int rc;
304
305         trace_xprtrdma_conn_start(xprt);
306
307         init_completion(&ia->ri_done);
308         init_completion(&ia->ri_remove_done);
309
310         id = rdma_create_id(xprt->rx_xprt.xprt_net, rpcrdma_cm_event_handler,
311                             xprt, RDMA_PS_TCP, IB_QPT_RC);
312         if (IS_ERR(id))
313                 return id;
314
315         ia->ri_async_rc = -ETIMEDOUT;
316         rc = rdma_resolve_addr(id, NULL,
317                                (struct sockaddr *)&xprt->rx_xprt.addr,
318                                RDMA_RESOLVE_TIMEOUT);
319         if (rc)
320                 goto out;
321         rc = wait_for_completion_interruptible_timeout(&ia->ri_done, wtimeout);
322         if (rc < 0) {
323                 trace_xprtrdma_conn_tout(xprt);
324                 goto out;
325         }
326
327         rc = ia->ri_async_rc;
328         if (rc)
329                 goto out;
330
331         ia->ri_async_rc = -ETIMEDOUT;
332         rc = rdma_resolve_route(id, RDMA_RESOLVE_TIMEOUT);
333         if (rc)
334                 goto out;
335         rc = wait_for_completion_interruptible_timeout(&ia->ri_done, wtimeout);
336         if (rc < 0) {
337                 trace_xprtrdma_conn_tout(xprt);
338                 goto out;
339         }
340         rc = ia->ri_async_rc;
341         if (rc)
342                 goto out;
343
344         return id;
345
346 out:
347         rdma_destroy_id(id);
348         return ERR_PTR(rc);
349 }
350
351 /*
352  * Exported functions.
353  */
354
355 /**
356  * rpcrdma_ia_open - Open and initialize an Interface Adapter.
357  * @xprt: transport with IA to (re)initialize
358  *
359  * Returns 0 on success, negative errno if an appropriate
360  * Interface Adapter could not be found and opened.
361  */
362 int
363 rpcrdma_ia_open(struct rpcrdma_xprt *xprt)
364 {
365         struct rpcrdma_ia *ia = &xprt->rx_ia;
366         int rc;
367
368         ia->ri_id = rpcrdma_create_id(xprt, ia);
369         if (IS_ERR(ia->ri_id)) {
370                 rc = PTR_ERR(ia->ri_id);
371                 goto out_err;
372         }
373         ia->ri_device = ia->ri_id->device;
374
375         ia->ri_pd = ib_alloc_pd(ia->ri_device, 0);
376         if (IS_ERR(ia->ri_pd)) {
377                 rc = PTR_ERR(ia->ri_pd);
378                 pr_err("rpcrdma: ib_alloc_pd() returned %d\n", rc);
379                 goto out_err;
380         }
381
382         switch (xprt_rdma_memreg_strategy) {
383         case RPCRDMA_FRWR:
384                 if (frwr_is_supported(ia))
385                         break;
386                 /*FALLTHROUGH*/
387         default:
388                 pr_err("rpcrdma: Device %s does not support memreg mode %d\n",
389                        ia->ri_device->name, xprt_rdma_memreg_strategy);
390                 rc = -EINVAL;
391                 goto out_err;
392         }
393
394         return 0;
395
396 out_err:
397         rpcrdma_ia_close(ia);
398         return rc;
399 }
400
401 /**
402  * rpcrdma_ia_remove - Handle device driver unload
403  * @ia: interface adapter being removed
404  *
405  * Divest transport H/W resources associated with this adapter,
406  * but allow it to be restored later.
407  */
408 void
409 rpcrdma_ia_remove(struct rpcrdma_ia *ia)
410 {
411         struct rpcrdma_xprt *r_xprt = container_of(ia, struct rpcrdma_xprt,
412                                                    rx_ia);
413         struct rpcrdma_ep *ep = &r_xprt->rx_ep;
414         struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
415         struct rpcrdma_req *req;
416         struct rpcrdma_rep *rep;
417
418         cancel_delayed_work_sync(&buf->rb_refresh_worker);
419
420         /* This is similar to rpcrdma_ep_destroy, but:
421          * - Don't cancel the connect worker.
422          * - Don't call rpcrdma_ep_disconnect, which waits
423          *   for another conn upcall, which will deadlock.
424          * - rdma_disconnect is unneeded, the underlying
425          *   connection is already gone.
426          */
427         if (ia->ri_id->qp) {
428                 rpcrdma_xprt_drain(r_xprt);
429                 rdma_destroy_qp(ia->ri_id);
430                 ia->ri_id->qp = NULL;
431         }
432         ib_free_cq(ep->rep_attr.recv_cq);
433         ep->rep_attr.recv_cq = NULL;
434         ib_free_cq(ep->rep_attr.send_cq);
435         ep->rep_attr.send_cq = NULL;
436
437         /* The ULP is responsible for ensuring all DMA
438          * mappings and MRs are gone.
439          */
440         list_for_each_entry(rep, &buf->rb_recv_bufs, rr_list)
441                 rpcrdma_dma_unmap_regbuf(rep->rr_rdmabuf);
442         list_for_each_entry(req, &buf->rb_allreqs, rl_all) {
443                 rpcrdma_dma_unmap_regbuf(req->rl_rdmabuf);
444                 rpcrdma_dma_unmap_regbuf(req->rl_sendbuf);
445                 rpcrdma_dma_unmap_regbuf(req->rl_recvbuf);
446         }
447         rpcrdma_mrs_destroy(buf);
448         ib_dealloc_pd(ia->ri_pd);
449         ia->ri_pd = NULL;
450
451         /* Allow waiters to continue */
452         complete(&ia->ri_remove_done);
453
454         trace_xprtrdma_remove(r_xprt);
455 }
456
457 /**
458  * rpcrdma_ia_close - Clean up/close an IA.
459  * @ia: interface adapter to close
460  *
461  */
462 void
463 rpcrdma_ia_close(struct rpcrdma_ia *ia)
464 {
465         if (ia->ri_id != NULL && !IS_ERR(ia->ri_id)) {
466                 if (ia->ri_id->qp)
467                         rdma_destroy_qp(ia->ri_id);
468                 rdma_destroy_id(ia->ri_id);
469         }
470         ia->ri_id = NULL;
471         ia->ri_device = NULL;
472
473         /* If the pd is still busy, xprtrdma missed freeing a resource */
474         if (ia->ri_pd && !IS_ERR(ia->ri_pd))
475                 ib_dealloc_pd(ia->ri_pd);
476         ia->ri_pd = NULL;
477 }
478
479 /*
480  * Create unconnected endpoint.
481  */
482 int
483 rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
484                   struct rpcrdma_create_data_internal *cdata)
485 {
486         struct rpcrdma_connect_private *pmsg = &ep->rep_cm_private;
487         struct ib_cq *sendcq, *recvcq;
488         unsigned int max_sge;
489         int rc;
490
491         max_sge = min_t(unsigned int, ia->ri_device->attrs.max_send_sge,
492                         RPCRDMA_MAX_SEND_SGES);
493         if (max_sge < RPCRDMA_MIN_SEND_SGES) {
494                 pr_warn("rpcrdma: HCA provides only %d send SGEs\n", max_sge);
495                 return -ENOMEM;
496         }
497         ia->ri_max_send_sges = max_sge;
498
499         rc = frwr_open(ia, ep, cdata);
500         if (rc)
501                 return rc;
502
503         ep->rep_attr.event_handler = rpcrdma_qp_event_handler;
504         ep->rep_attr.qp_context = ep;
505         ep->rep_attr.srq = NULL;
506         ep->rep_attr.cap.max_send_sge = max_sge;
507         ep->rep_attr.cap.max_recv_sge = 1;
508         ep->rep_attr.cap.max_inline_data = 0;
509         ep->rep_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
510         ep->rep_attr.qp_type = IB_QPT_RC;
511         ep->rep_attr.port_num = ~0;
512
513         dprintk("RPC:       %s: requested max: dtos: send %d recv %d; "
514                 "iovs: send %d recv %d\n",
515                 __func__,
516                 ep->rep_attr.cap.max_send_wr,
517                 ep->rep_attr.cap.max_recv_wr,
518                 ep->rep_attr.cap.max_send_sge,
519                 ep->rep_attr.cap.max_recv_sge);
520
521         /* set trigger for requesting send completion */
522         ep->rep_send_batch = min_t(unsigned int, RPCRDMA_MAX_SEND_BATCH,
523                                    cdata->max_requests >> 2);
524         ep->rep_send_count = ep->rep_send_batch;
525         init_waitqueue_head(&ep->rep_connect_wait);
526         ep->rep_receive_count = 0;
527
528         sendcq = ib_alloc_cq(ia->ri_device, NULL,
529                              ep->rep_attr.cap.max_send_wr + 1,
530                              1, IB_POLL_WORKQUEUE);
531         if (IS_ERR(sendcq)) {
532                 rc = PTR_ERR(sendcq);
533                 goto out1;
534         }
535
536         recvcq = ib_alloc_cq(ia->ri_device, NULL,
537                              ep->rep_attr.cap.max_recv_wr + 1,
538                              0, IB_POLL_WORKQUEUE);
539         if (IS_ERR(recvcq)) {
540                 rc = PTR_ERR(recvcq);
541                 goto out2;
542         }
543
544         ep->rep_attr.send_cq = sendcq;
545         ep->rep_attr.recv_cq = recvcq;
546
547         /* Initialize cma parameters */
548         memset(&ep->rep_remote_cma, 0, sizeof(ep->rep_remote_cma));
549
550         /* Prepare RDMA-CM private message */
551         pmsg->cp_magic = rpcrdma_cmp_magic;
552         pmsg->cp_version = RPCRDMA_CMP_VERSION;
553         pmsg->cp_flags |= RPCRDMA_CMP_F_SND_W_INV_OK;
554         pmsg->cp_send_size = rpcrdma_encode_buffer_size(cdata->inline_wsize);
555         pmsg->cp_recv_size = rpcrdma_encode_buffer_size(cdata->inline_rsize);
556         ep->rep_remote_cma.private_data = pmsg;
557         ep->rep_remote_cma.private_data_len = sizeof(*pmsg);
558
559         /* Client offers RDMA Read but does not initiate */
560         ep->rep_remote_cma.initiator_depth = 0;
561         ep->rep_remote_cma.responder_resources =
562                 min_t(int, U8_MAX, ia->ri_device->attrs.max_qp_rd_atom);
563
564         /* Limit transport retries so client can detect server
565          * GID changes quickly. RPC layer handles re-establishing
566          * transport connection and retransmission.
567          */
568         ep->rep_remote_cma.retry_count = 6;
569
570         /* RPC-over-RDMA handles its own flow control. In addition,
571          * make all RNR NAKs visible so we know that RPC-over-RDMA
572          * flow control is working correctly (no NAKs should be seen).
573          */
574         ep->rep_remote_cma.flow_control = 0;
575         ep->rep_remote_cma.rnr_retry_count = 0;
576
577         return 0;
578
579 out2:
580         ib_free_cq(sendcq);
581 out1:
582         return rc;
583 }
584
585 /*
586  * rpcrdma_ep_destroy
587  *
588  * Disconnect and destroy endpoint. After this, the only
589  * valid operations on the ep are to free it (if dynamically
590  * allocated) or re-create it.
591  */
592 void
593 rpcrdma_ep_destroy(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
594 {
595         if (ia->ri_id && ia->ri_id->qp) {
596                 rpcrdma_ep_disconnect(ep, ia);
597                 rdma_destroy_qp(ia->ri_id);
598                 ia->ri_id->qp = NULL;
599         }
600
601         if (ep->rep_attr.recv_cq)
602                 ib_free_cq(ep->rep_attr.recv_cq);
603         if (ep->rep_attr.send_cq)
604                 ib_free_cq(ep->rep_attr.send_cq);
605 }
606
607 /* Re-establish a connection after a device removal event.
608  * Unlike a normal reconnection, a fresh PD and a new set
609  * of MRs and buffers is needed.
610  */
611 static int
612 rpcrdma_ep_recreate_xprt(struct rpcrdma_xprt *r_xprt,
613                          struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
614 {
615         int rc, err;
616
617         trace_xprtrdma_reinsert(r_xprt);
618
619         rc = -EHOSTUNREACH;
620         if (rpcrdma_ia_open(r_xprt))
621                 goto out1;
622
623         rc = -ENOMEM;
624         err = rpcrdma_ep_create(ep, ia, &r_xprt->rx_data);
625         if (err) {
626                 pr_err("rpcrdma: rpcrdma_ep_create returned %d\n", err);
627                 goto out2;
628         }
629
630         rc = -ENETUNREACH;
631         err = rdma_create_qp(ia->ri_id, ia->ri_pd, &ep->rep_attr);
632         if (err) {
633                 pr_err("rpcrdma: rdma_create_qp returned %d\n", err);
634                 goto out3;
635         }
636
637         rpcrdma_mrs_create(r_xprt);
638         return 0;
639
640 out3:
641         rpcrdma_ep_destroy(ep, ia);
642 out2:
643         rpcrdma_ia_close(ia);
644 out1:
645         return rc;
646 }
647
648 static int
649 rpcrdma_ep_reconnect(struct rpcrdma_xprt *r_xprt, struct rpcrdma_ep *ep,
650                      struct rpcrdma_ia *ia)
651 {
652         struct rdma_cm_id *id, *old;
653         int err, rc;
654
655         trace_xprtrdma_reconnect(r_xprt);
656
657         rpcrdma_ep_disconnect(ep, ia);
658
659         rc = -EHOSTUNREACH;
660         id = rpcrdma_create_id(r_xprt, ia);
661         if (IS_ERR(id))
662                 goto out;
663
664         /* As long as the new ID points to the same device as the
665          * old ID, we can reuse the transport's existing PD and all
666          * previously allocated MRs. Also, the same device means
667          * the transport's previous DMA mappings are still valid.
668          *
669          * This is a sanity check only. There should be no way these
670          * point to two different devices here.
671          */
672         old = id;
673         rc = -ENETUNREACH;
674         if (ia->ri_device != id->device) {
675                 pr_err("rpcrdma: can't reconnect on different device!\n");
676                 goto out_destroy;
677         }
678
679         err = rdma_create_qp(id, ia->ri_pd, &ep->rep_attr);
680         if (err)
681                 goto out_destroy;
682
683         /* Atomically replace the transport's ID and QP. */
684         rc = 0;
685         old = ia->ri_id;
686         ia->ri_id = id;
687         rdma_destroy_qp(old);
688
689 out_destroy:
690         rdma_destroy_id(old);
691 out:
692         return rc;
693 }
694
695 /*
696  * Connect unconnected endpoint.
697  */
698 int
699 rpcrdma_ep_connect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
700 {
701         struct rpcrdma_xprt *r_xprt = container_of(ia, struct rpcrdma_xprt,
702                                                    rx_ia);
703         struct rpc_xprt *xprt = &r_xprt->rx_xprt;
704         int rc;
705
706 retry:
707         switch (ep->rep_connected) {
708         case 0:
709                 dprintk("RPC:       %s: connecting...\n", __func__);
710                 rc = rdma_create_qp(ia->ri_id, ia->ri_pd, &ep->rep_attr);
711                 if (rc) {
712                         rc = -ENETUNREACH;
713                         goto out_noupdate;
714                 }
715                 break;
716         case -ENODEV:
717                 rc = rpcrdma_ep_recreate_xprt(r_xprt, ep, ia);
718                 if (rc)
719                         goto out_noupdate;
720                 break;
721         default:
722                 rc = rpcrdma_ep_reconnect(r_xprt, ep, ia);
723                 if (rc)
724                         goto out;
725         }
726
727         ep->rep_connected = 0;
728         xprt_clear_connected(xprt);
729
730         rpcrdma_post_recvs(r_xprt, true);
731
732         rc = rdma_connect(ia->ri_id, &ep->rep_remote_cma);
733         if (rc)
734                 goto out;
735
736         wait_event_interruptible(ep->rep_connect_wait, ep->rep_connected != 0);
737         if (ep->rep_connected <= 0) {
738                 if (ep->rep_connected == -EAGAIN)
739                         goto retry;
740                 rc = ep->rep_connected;
741                 goto out;
742         }
743
744         dprintk("RPC:       %s: connected\n", __func__);
745
746 out:
747         if (rc)
748                 ep->rep_connected = rc;
749
750 out_noupdate:
751         return rc;
752 }
753
754 /**
755  * rpcrdma_ep_disconnect - Disconnect underlying transport
756  * @ep: endpoint to disconnect
757  * @ia: associated interface adapter
758  *
759  * This is separate from destroy to facilitate the ability
760  * to reconnect without recreating the endpoint.
761  *
762  * This call is not reentrant, and must not be made in parallel
763  * on the same endpoint.
764  */
765 void
766 rpcrdma_ep_disconnect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
767 {
768         struct rpcrdma_xprt *r_xprt = container_of(ep, struct rpcrdma_xprt,
769                                                    rx_ep);
770         int rc;
771
772         /* returns without wait if ID is not connected */
773         rc = rdma_disconnect(ia->ri_id);
774         if (!rc)
775                 wait_event_interruptible(ep->rep_connect_wait,
776                                                         ep->rep_connected != 1);
777         else
778                 ep->rep_connected = rc;
779         trace_xprtrdma_disconnect(r_xprt, rc);
780
781         rpcrdma_xprt_drain(r_xprt);
782 }
783
784 /* Fixed-size circular FIFO queue. This implementation is wait-free and
785  * lock-free.
786  *
787  * Consumer is the code path that posts Sends. This path dequeues a
788  * sendctx for use by a Send operation. Multiple consumer threads
789  * are serialized by the RPC transport lock, which allows only one
790  * ->send_request call at a time.
791  *
792  * Producer is the code path that handles Send completions. This path
793  * enqueues a sendctx that has been completed. Multiple producer
794  * threads are serialized by the ib_poll_cq() function.
795  */
796
797 /* rpcrdma_sendctxs_destroy() assumes caller has already quiesced
798  * queue activity, and ib_drain_qp has flushed all remaining Send
799  * requests.
800  */
801 static void rpcrdma_sendctxs_destroy(struct rpcrdma_buffer *buf)
802 {
803         unsigned long i;
804
805         for (i = 0; i <= buf->rb_sc_last; i++)
806                 kfree(buf->rb_sc_ctxs[i]);
807         kfree(buf->rb_sc_ctxs);
808 }
809
810 static struct rpcrdma_sendctx *rpcrdma_sendctx_create(struct rpcrdma_ia *ia)
811 {
812         struct rpcrdma_sendctx *sc;
813
814         sc = kzalloc(sizeof(*sc) +
815                      ia->ri_max_send_sges * sizeof(struct ib_sge),
816                      GFP_KERNEL);
817         if (!sc)
818                 return NULL;
819
820         sc->sc_wr.wr_cqe = &sc->sc_cqe;
821         sc->sc_wr.sg_list = sc->sc_sges;
822         sc->sc_wr.opcode = IB_WR_SEND;
823         sc->sc_cqe.done = rpcrdma_wc_send;
824         return sc;
825 }
826
827 static int rpcrdma_sendctxs_create(struct rpcrdma_xprt *r_xprt)
828 {
829         struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
830         struct rpcrdma_sendctx *sc;
831         unsigned long i;
832
833         /* Maximum number of concurrent outstanding Send WRs. Capping
834          * the circular queue size stops Send Queue overflow by causing
835          * the ->send_request call to fail temporarily before too many
836          * Sends are posted.
837          */
838         i = buf->rb_max_requests + RPCRDMA_MAX_BC_REQUESTS;
839         dprintk("RPC:       %s: allocating %lu send_ctxs\n", __func__, i);
840         buf->rb_sc_ctxs = kcalloc(i, sizeof(sc), GFP_KERNEL);
841         if (!buf->rb_sc_ctxs)
842                 return -ENOMEM;
843
844         buf->rb_sc_last = i - 1;
845         for (i = 0; i <= buf->rb_sc_last; i++) {
846                 sc = rpcrdma_sendctx_create(&r_xprt->rx_ia);
847                 if (!sc)
848                         return -ENOMEM;
849
850                 sc->sc_xprt = r_xprt;
851                 buf->rb_sc_ctxs[i] = sc;
852         }
853
854         return 0;
855 }
856
857 /* The sendctx queue is not guaranteed to have a size that is a
858  * power of two, thus the helpers in circ_buf.h cannot be used.
859  * The other option is to use modulus (%), which can be expensive.
860  */
861 static unsigned long rpcrdma_sendctx_next(struct rpcrdma_buffer *buf,
862                                           unsigned long item)
863 {
864         return likely(item < buf->rb_sc_last) ? item + 1 : 0;
865 }
866
867 /**
868  * rpcrdma_sendctx_get_locked - Acquire a send context
869  * @buf: transport buffers from which to acquire an unused context
870  *
871  * Returns pointer to a free send completion context; or NULL if
872  * the queue is empty.
873  *
874  * Usage: Called to acquire an SGE array before preparing a Send WR.
875  *
876  * The caller serializes calls to this function (per rpcrdma_buffer),
877  * and provides an effective memory barrier that flushes the new value
878  * of rb_sc_head.
879  */
880 struct rpcrdma_sendctx *rpcrdma_sendctx_get_locked(struct rpcrdma_buffer *buf)
881 {
882         struct rpcrdma_xprt *r_xprt;
883         struct rpcrdma_sendctx *sc;
884         unsigned long next_head;
885
886         next_head = rpcrdma_sendctx_next(buf, buf->rb_sc_head);
887
888         if (next_head == READ_ONCE(buf->rb_sc_tail))
889                 goto out_emptyq;
890
891         /* ORDER: item must be accessed _before_ head is updated */
892         sc = buf->rb_sc_ctxs[next_head];
893
894         /* Releasing the lock in the caller acts as a memory
895          * barrier that flushes rb_sc_head.
896          */
897         buf->rb_sc_head = next_head;
898
899         return sc;
900
901 out_emptyq:
902         /* The queue is "empty" if there have not been enough Send
903          * completions recently. This is a sign the Send Queue is
904          * backing up. Cause the caller to pause and try again.
905          */
906         set_bit(RPCRDMA_BUF_F_EMPTY_SCQ, &buf->rb_flags);
907         r_xprt = container_of(buf, struct rpcrdma_xprt, rx_buf);
908         r_xprt->rx_stats.empty_sendctx_q++;
909         return NULL;
910 }
911
912 /**
913  * rpcrdma_sendctx_put_locked - Release a send context
914  * @sc: send context to release
915  *
916  * Usage: Called from Send completion to return a sendctxt
917  * to the queue.
918  *
919  * The caller serializes calls to this function (per rpcrdma_buffer).
920  */
921 static void
922 rpcrdma_sendctx_put_locked(struct rpcrdma_sendctx *sc)
923 {
924         struct rpcrdma_buffer *buf = &sc->sc_xprt->rx_buf;
925         unsigned long next_tail;
926
927         /* Unmap SGEs of previously completed by unsignaled
928          * Sends by walking up the queue until @sc is found.
929          */
930         next_tail = buf->rb_sc_tail;
931         do {
932                 next_tail = rpcrdma_sendctx_next(buf, next_tail);
933
934                 /* ORDER: item must be accessed _before_ tail is updated */
935                 rpcrdma_unmap_sendctx(buf->rb_sc_ctxs[next_tail]);
936
937         } while (buf->rb_sc_ctxs[next_tail] != sc);
938
939         /* Paired with READ_ONCE */
940         smp_store_release(&buf->rb_sc_tail, next_tail);
941
942         if (test_and_clear_bit(RPCRDMA_BUF_F_EMPTY_SCQ, &buf->rb_flags)) {
943                 smp_mb__after_atomic();
944                 xprt_write_space(&sc->sc_xprt->rx_xprt);
945         }
946 }
947
948 static void
949 rpcrdma_mrs_create(struct rpcrdma_xprt *r_xprt)
950 {
951         struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
952         struct rpcrdma_ia *ia = &r_xprt->rx_ia;
953         unsigned int count;
954         LIST_HEAD(free);
955         LIST_HEAD(all);
956
957         for (count = 0; count < ia->ri_max_segs; count++) {
958                 struct rpcrdma_mr *mr;
959                 int rc;
960
961                 mr = kzalloc(sizeof(*mr), GFP_KERNEL);
962                 if (!mr)
963                         break;
964
965                 rc = frwr_init_mr(ia, mr);
966                 if (rc) {
967                         kfree(mr);
968                         break;
969                 }
970
971                 mr->mr_xprt = r_xprt;
972
973                 list_add(&mr->mr_list, &free);
974                 list_add(&mr->mr_all, &all);
975         }
976
977         spin_lock(&buf->rb_mrlock);
978         list_splice(&free, &buf->rb_mrs);
979         list_splice(&all, &buf->rb_all);
980         r_xprt->rx_stats.mrs_allocated += count;
981         spin_unlock(&buf->rb_mrlock);
982         trace_xprtrdma_createmrs(r_xprt, count);
983
984         xprt_write_space(&r_xprt->rx_xprt);
985 }
986
987 static void
988 rpcrdma_mr_refresh_worker(struct work_struct *work)
989 {
990         struct rpcrdma_buffer *buf = container_of(work, struct rpcrdma_buffer,
991                                                   rb_refresh_worker.work);
992         struct rpcrdma_xprt *r_xprt = container_of(buf, struct rpcrdma_xprt,
993                                                    rx_buf);
994
995         rpcrdma_mrs_create(r_xprt);
996 }
997
998 struct rpcrdma_req *
999 rpcrdma_create_req(struct rpcrdma_xprt *r_xprt)
1000 {
1001         struct rpcrdma_buffer *buffer = &r_xprt->rx_buf;
1002         struct rpcrdma_regbuf *rb;
1003         struct rpcrdma_req *req;
1004
1005         req = kzalloc(sizeof(*req), GFP_KERNEL);
1006         if (req == NULL)
1007                 return ERR_PTR(-ENOMEM);
1008
1009         rb = rpcrdma_alloc_regbuf(RPCRDMA_HDRBUF_SIZE,
1010                                   DMA_TO_DEVICE, GFP_KERNEL);
1011         if (IS_ERR(rb)) {
1012                 kfree(req);
1013                 return ERR_PTR(-ENOMEM);
1014         }
1015         req->rl_rdmabuf = rb;
1016         xdr_buf_init(&req->rl_hdrbuf, rb->rg_base, rdmab_length(rb));
1017         req->rl_buffer = buffer;
1018         INIT_LIST_HEAD(&req->rl_registered);
1019
1020         spin_lock(&buffer->rb_lock);
1021         list_add(&req->rl_all, &buffer->rb_allreqs);
1022         spin_unlock(&buffer->rb_lock);
1023         return req;
1024 }
1025
1026 static int
1027 rpcrdma_create_rep(struct rpcrdma_xprt *r_xprt, bool temp)
1028 {
1029         struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data;
1030         struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
1031         struct rpcrdma_rep *rep;
1032         int rc;
1033
1034         rc = -ENOMEM;
1035         rep = kzalloc(sizeof(*rep), GFP_KERNEL);
1036         if (rep == NULL)
1037                 goto out;
1038
1039         rep->rr_rdmabuf = rpcrdma_alloc_regbuf(cdata->inline_rsize,
1040                                                DMA_FROM_DEVICE, GFP_KERNEL);
1041         if (IS_ERR(rep->rr_rdmabuf)) {
1042                 rc = PTR_ERR(rep->rr_rdmabuf);
1043                 goto out_free;
1044         }
1045         xdr_buf_init(&rep->rr_hdrbuf, rep->rr_rdmabuf->rg_base,
1046                      rdmab_length(rep->rr_rdmabuf));
1047
1048         rep->rr_cqe.done = rpcrdma_wc_receive;
1049         rep->rr_rxprt = r_xprt;
1050         INIT_WORK(&rep->rr_work, rpcrdma_deferred_completion);
1051         rep->rr_recv_wr.next = NULL;
1052         rep->rr_recv_wr.wr_cqe = &rep->rr_cqe;
1053         rep->rr_recv_wr.sg_list = &rep->rr_rdmabuf->rg_iov;
1054         rep->rr_recv_wr.num_sge = 1;
1055         rep->rr_temp = temp;
1056
1057         spin_lock(&buf->rb_lock);
1058         list_add(&rep->rr_list, &buf->rb_recv_bufs);
1059         spin_unlock(&buf->rb_lock);
1060         return 0;
1061
1062 out_free:
1063         kfree(rep);
1064 out:
1065         return rc;
1066 }
1067
1068 int
1069 rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt)
1070 {
1071         struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
1072         int i, rc;
1073
1074         buf->rb_flags = 0;
1075         buf->rb_max_requests = r_xprt->rx_data.max_requests;
1076         buf->rb_bc_srv_max_requests = 0;
1077         spin_lock_init(&buf->rb_mrlock);
1078         spin_lock_init(&buf->rb_lock);
1079         INIT_LIST_HEAD(&buf->rb_mrs);
1080         INIT_LIST_HEAD(&buf->rb_all);
1081         INIT_DELAYED_WORK(&buf->rb_refresh_worker,
1082                           rpcrdma_mr_refresh_worker);
1083
1084         rpcrdma_mrs_create(r_xprt);
1085
1086         INIT_LIST_HEAD(&buf->rb_send_bufs);
1087         INIT_LIST_HEAD(&buf->rb_allreqs);
1088         for (i = 0; i < buf->rb_max_requests; i++) {
1089                 struct rpcrdma_req *req;
1090
1091                 req = rpcrdma_create_req(r_xprt);
1092                 if (IS_ERR(req)) {
1093                         dprintk("RPC:       %s: request buffer %d alloc"
1094                                 " failed\n", __func__, i);
1095                         rc = PTR_ERR(req);
1096                         goto out;
1097                 }
1098                 list_add(&req->rl_list, &buf->rb_send_bufs);
1099         }
1100
1101         buf->rb_credits = 1;
1102         INIT_LIST_HEAD(&buf->rb_recv_bufs);
1103
1104         rc = rpcrdma_sendctxs_create(r_xprt);
1105         if (rc)
1106                 goto out;
1107
1108         buf->rb_completion_wq = alloc_workqueue("rpcrdma-%s",
1109                                                 WQ_MEM_RECLAIM | WQ_HIGHPRI,
1110                                                 0,
1111                         r_xprt->rx_xprt.address_strings[RPC_DISPLAY_ADDR]);
1112         if (!buf->rb_completion_wq) {
1113                 rc = -ENOMEM;
1114                 goto out;
1115         }
1116
1117         return 0;
1118 out:
1119         rpcrdma_buffer_destroy(buf);
1120         return rc;
1121 }
1122
1123 static void
1124 rpcrdma_destroy_rep(struct rpcrdma_rep *rep)
1125 {
1126         rpcrdma_free_regbuf(rep->rr_rdmabuf);
1127         kfree(rep);
1128 }
1129
1130 /**
1131  * rpcrdma_req_destroy - Destroy an rpcrdma_req object
1132  * @req: unused object to be destroyed
1133  *
1134  * This function assumes that the caller prevents concurrent device
1135  * unload and transport tear-down.
1136  */
1137 void
1138 rpcrdma_req_destroy(struct rpcrdma_req *req)
1139 {
1140         list_del(&req->rl_all);
1141
1142         rpcrdma_free_regbuf(req->rl_recvbuf);
1143         rpcrdma_free_regbuf(req->rl_sendbuf);
1144         rpcrdma_free_regbuf(req->rl_rdmabuf);
1145         kfree(req);
1146 }
1147
1148 static void
1149 rpcrdma_mrs_destroy(struct rpcrdma_buffer *buf)
1150 {
1151         struct rpcrdma_xprt *r_xprt = container_of(buf, struct rpcrdma_xprt,
1152                                                    rx_buf);
1153         struct rpcrdma_mr *mr;
1154         unsigned int count;
1155
1156         count = 0;
1157         spin_lock(&buf->rb_mrlock);
1158         while (!list_empty(&buf->rb_all)) {
1159                 mr = list_entry(buf->rb_all.next, struct rpcrdma_mr, mr_all);
1160                 list_del(&mr->mr_all);
1161
1162                 spin_unlock(&buf->rb_mrlock);
1163
1164                 /* Ensure MW is not on any rl_registered list */
1165                 if (!list_empty(&mr->mr_list))
1166                         list_del(&mr->mr_list);
1167
1168                 frwr_release_mr(mr);
1169                 count++;
1170                 spin_lock(&buf->rb_mrlock);
1171         }
1172         spin_unlock(&buf->rb_mrlock);
1173         r_xprt->rx_stats.mrs_allocated = 0;
1174
1175         dprintk("RPC:       %s: released %u MRs\n", __func__, count);
1176 }
1177
1178 /**
1179  * rpcrdma_buffer_destroy - Release all hw resources
1180  * @buf: root control block for resources
1181  *
1182  * ORDERING: relies on a prior ib_drain_qp :
1183  * - No more Send or Receive completions can occur
1184  * - All MRs, reps, and reqs are returned to their free lists
1185  */
1186 void
1187 rpcrdma_buffer_destroy(struct rpcrdma_buffer *buf)
1188 {
1189         cancel_delayed_work_sync(&buf->rb_refresh_worker);
1190
1191         if (buf->rb_completion_wq) {
1192                 destroy_workqueue(buf->rb_completion_wq);
1193                 buf->rb_completion_wq = NULL;
1194         }
1195
1196         rpcrdma_sendctxs_destroy(buf);
1197
1198         while (!list_empty(&buf->rb_recv_bufs)) {
1199                 struct rpcrdma_rep *rep;
1200
1201                 rep = list_first_entry(&buf->rb_recv_bufs,
1202                                        struct rpcrdma_rep, rr_list);
1203                 list_del(&rep->rr_list);
1204                 rpcrdma_destroy_rep(rep);
1205         }
1206
1207         while (!list_empty(&buf->rb_send_bufs)) {
1208                 struct rpcrdma_req *req;
1209
1210                 req = list_first_entry(&buf->rb_send_bufs,
1211                                        struct rpcrdma_req, rl_list);
1212                 list_del(&req->rl_list);
1213                 rpcrdma_req_destroy(req);
1214         }
1215
1216         rpcrdma_mrs_destroy(buf);
1217 }
1218
1219 /**
1220  * rpcrdma_mr_get - Allocate an rpcrdma_mr object
1221  * @r_xprt: controlling transport
1222  *
1223  * Returns an initialized rpcrdma_mr or NULL if no free
1224  * rpcrdma_mr objects are available.
1225  */
1226 struct rpcrdma_mr *
1227 rpcrdma_mr_get(struct rpcrdma_xprt *r_xprt)
1228 {
1229         struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
1230         struct rpcrdma_mr *mr = NULL;
1231
1232         spin_lock(&buf->rb_mrlock);
1233         if (!list_empty(&buf->rb_mrs))
1234                 mr = rpcrdma_mr_pop(&buf->rb_mrs);
1235         spin_unlock(&buf->rb_mrlock);
1236
1237         if (!mr)
1238                 goto out_nomrs;
1239         return mr;
1240
1241 out_nomrs:
1242         trace_xprtrdma_nomrs(r_xprt);
1243         if (r_xprt->rx_ep.rep_connected != -ENODEV)
1244                 schedule_delayed_work(&buf->rb_refresh_worker, 0);
1245
1246         /* Allow the reply handler and refresh worker to run */
1247         cond_resched();
1248
1249         return NULL;
1250 }
1251
1252 static void
1253 __rpcrdma_mr_put(struct rpcrdma_buffer *buf, struct rpcrdma_mr *mr)
1254 {
1255         spin_lock(&buf->rb_mrlock);
1256         rpcrdma_mr_push(mr, &buf->rb_mrs);
1257         spin_unlock(&buf->rb_mrlock);
1258 }
1259
1260 /**
1261  * rpcrdma_mr_put - Release an rpcrdma_mr object
1262  * @mr: object to release
1263  *
1264  */
1265 void
1266 rpcrdma_mr_put(struct rpcrdma_mr *mr)
1267 {
1268         __rpcrdma_mr_put(&mr->mr_xprt->rx_buf, mr);
1269 }
1270
1271 /**
1272  * rpcrdma_mr_unmap_and_put - DMA unmap an MR and release it
1273  * @mr: object to release
1274  *
1275  */
1276 void
1277 rpcrdma_mr_unmap_and_put(struct rpcrdma_mr *mr)
1278 {
1279         struct rpcrdma_xprt *r_xprt = mr->mr_xprt;
1280
1281         if (mr->mr_dir != DMA_NONE) {
1282                 trace_xprtrdma_mr_unmap(mr);
1283                 ib_dma_unmap_sg(r_xprt->rx_ia.ri_device,
1284                                 mr->mr_sg, mr->mr_nents, mr->mr_dir);
1285                 mr->mr_dir = DMA_NONE;
1286         }
1287         __rpcrdma_mr_put(&r_xprt->rx_buf, mr);
1288 }
1289
1290 /**
1291  * rpcrdma_buffer_get - Get a request buffer
1292  * @buffers: Buffer pool from which to obtain a buffer
1293  *
1294  * Returns a fresh rpcrdma_req, or NULL if none are available.
1295  */
1296 struct rpcrdma_req *
1297 rpcrdma_buffer_get(struct rpcrdma_buffer *buffers)
1298 {
1299         struct rpcrdma_req *req;
1300
1301         spin_lock(&buffers->rb_lock);
1302         req = list_first_entry_or_null(&buffers->rb_send_bufs,
1303                                        struct rpcrdma_req, rl_list);
1304         if (req)
1305                 list_del_init(&req->rl_list);
1306         spin_unlock(&buffers->rb_lock);
1307         return req;
1308 }
1309
1310 /**
1311  * rpcrdma_buffer_put - Put request/reply buffers back into pool
1312  * @req: object to return
1313  *
1314  */
1315 void
1316 rpcrdma_buffer_put(struct rpcrdma_req *req)
1317 {
1318         struct rpcrdma_buffer *buffers = req->rl_buffer;
1319         struct rpcrdma_rep *rep = req->rl_reply;
1320
1321         req->rl_reply = NULL;
1322
1323         spin_lock(&buffers->rb_lock);
1324         list_add(&req->rl_list, &buffers->rb_send_bufs);
1325         if (rep) {
1326                 if (!rep->rr_temp) {
1327                         list_add(&rep->rr_list, &buffers->rb_recv_bufs);
1328                         rep = NULL;
1329                 }
1330         }
1331         spin_unlock(&buffers->rb_lock);
1332         if (rep)
1333                 rpcrdma_destroy_rep(rep);
1334 }
1335
1336 /*
1337  * Put reply buffers back into pool when not attached to
1338  * request. This happens in error conditions.
1339  */
1340 void
1341 rpcrdma_recv_buffer_put(struct rpcrdma_rep *rep)
1342 {
1343         struct rpcrdma_buffer *buffers = &rep->rr_rxprt->rx_buf;
1344
1345         if (!rep->rr_temp) {
1346                 spin_lock(&buffers->rb_lock);
1347                 list_add(&rep->rr_list, &buffers->rb_recv_bufs);
1348                 spin_unlock(&buffers->rb_lock);
1349         } else {
1350                 rpcrdma_destroy_rep(rep);
1351         }
1352 }
1353
1354 /**
1355  * rpcrdma_alloc_regbuf - allocate and DMA-map memory for SEND/RECV buffers
1356  * @size: size of buffer to be allocated, in bytes
1357  * @direction: direction of data movement
1358  * @flags: GFP flags
1359  *
1360  * Returns an ERR_PTR, or a pointer to a regbuf, a buffer that
1361  * can be persistently DMA-mapped for I/O.
1362  *
1363  * xprtrdma uses a regbuf for posting an outgoing RDMA SEND, or for
1364  * receiving the payload of RDMA RECV operations. During Long Calls
1365  * or Replies they may be registered externally via frwr_map.
1366  */
1367 struct rpcrdma_regbuf *
1368 rpcrdma_alloc_regbuf(size_t size, enum dma_data_direction direction,
1369                      gfp_t flags)
1370 {
1371         struct rpcrdma_regbuf *rb;
1372
1373         rb = kmalloc(sizeof(*rb) + size, flags);
1374         if (rb == NULL)
1375                 return ERR_PTR(-ENOMEM);
1376
1377         rb->rg_device = NULL;
1378         rb->rg_direction = direction;
1379         rb->rg_iov.length = size;
1380
1381         return rb;
1382 }
1383
1384 /**
1385  * __rpcrdma_map_regbuf - DMA-map a regbuf
1386  * @ia: controlling rpcrdma_ia
1387  * @rb: regbuf to be mapped
1388  */
1389 bool
1390 __rpcrdma_dma_map_regbuf(struct rpcrdma_ia *ia, struct rpcrdma_regbuf *rb)
1391 {
1392         struct ib_device *device = ia->ri_device;
1393
1394         if (rb->rg_direction == DMA_NONE)
1395                 return false;
1396
1397         rb->rg_iov.addr = ib_dma_map_single(device,
1398                                             (void *)rb->rg_base,
1399                                             rdmab_length(rb),
1400                                             rb->rg_direction);
1401         if (ib_dma_mapping_error(device, rdmab_addr(rb))) {
1402                 trace_xprtrdma_dma_maperr(rdmab_addr(rb));
1403                 return false;
1404         }
1405
1406         rb->rg_device = device;
1407         rb->rg_iov.lkey = ia->ri_pd->local_dma_lkey;
1408         return true;
1409 }
1410
1411 static void
1412 rpcrdma_dma_unmap_regbuf(struct rpcrdma_regbuf *rb)
1413 {
1414         if (!rb)
1415                 return;
1416
1417         if (!rpcrdma_regbuf_is_mapped(rb))
1418                 return;
1419
1420         ib_dma_unmap_single(rb->rg_device, rdmab_addr(rb),
1421                             rdmab_length(rb), rb->rg_direction);
1422         rb->rg_device = NULL;
1423 }
1424
1425 /**
1426  * rpcrdma_free_regbuf - deregister and free registered buffer
1427  * @rb: regbuf to be deregistered and freed
1428  */
1429 void
1430 rpcrdma_free_regbuf(struct rpcrdma_regbuf *rb)
1431 {
1432         rpcrdma_dma_unmap_regbuf(rb);
1433         kfree(rb);
1434 }
1435
1436 /**
1437  * rpcrdma_ep_post - Post WRs to a transport's Send Queue
1438  * @ia: transport's device information
1439  * @ep: transport's RDMA endpoint information
1440  * @req: rpcrdma_req containing the Send WR to post
1441  *
1442  * Returns 0 if the post was successful, otherwise -ENOTCONN
1443  * is returned.
1444  */
1445 int
1446 rpcrdma_ep_post(struct rpcrdma_ia *ia,
1447                 struct rpcrdma_ep *ep,
1448                 struct rpcrdma_req *req)
1449 {
1450         struct ib_send_wr *send_wr = &req->rl_sendctx->sc_wr;
1451         int rc;
1452
1453         if (!ep->rep_send_count ||
1454             test_bit(RPCRDMA_REQ_F_TX_RESOURCES, &req->rl_flags)) {
1455                 send_wr->send_flags |= IB_SEND_SIGNALED;
1456                 ep->rep_send_count = ep->rep_send_batch;
1457         } else {
1458                 send_wr->send_flags &= ~IB_SEND_SIGNALED;
1459                 --ep->rep_send_count;
1460         }
1461
1462         rc = frwr_send(ia, req);
1463         trace_xprtrdma_post_send(req, rc);
1464         if (rc)
1465                 return -ENOTCONN;
1466         return 0;
1467 }
1468
1469 static void
1470 rpcrdma_post_recvs(struct rpcrdma_xprt *r_xprt, bool temp)
1471 {
1472         struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
1473         struct rpcrdma_ep *ep = &r_xprt->rx_ep;
1474         struct ib_recv_wr *wr, *bad_wr;
1475         int needed, count, rc;
1476
1477         rc = 0;
1478         count = 0;
1479         needed = buf->rb_credits + (buf->rb_bc_srv_max_requests << 1);
1480         if (ep->rep_receive_count > needed)
1481                 goto out;
1482         needed -= ep->rep_receive_count;
1483
1484         count = 0;
1485         wr = NULL;
1486         while (needed) {
1487                 struct rpcrdma_regbuf *rb;
1488                 struct rpcrdma_rep *rep;
1489
1490                 spin_lock(&buf->rb_lock);
1491                 rep = list_first_entry_or_null(&buf->rb_recv_bufs,
1492                                                struct rpcrdma_rep, rr_list);
1493                 if (likely(rep))
1494                         list_del(&rep->rr_list);
1495                 spin_unlock(&buf->rb_lock);
1496                 if (!rep) {
1497                         if (rpcrdma_create_rep(r_xprt, temp))
1498                                 break;
1499                         continue;
1500                 }
1501
1502                 rb = rep->rr_rdmabuf;
1503                 if (!rpcrdma_regbuf_is_mapped(rb)) {
1504                         if (!__rpcrdma_dma_map_regbuf(&r_xprt->rx_ia, rb)) {
1505                                 rpcrdma_recv_buffer_put(rep);
1506                                 break;
1507                         }
1508                 }
1509
1510                 trace_xprtrdma_post_recv(rep->rr_recv_wr.wr_cqe);
1511                 rep->rr_recv_wr.next = wr;
1512                 wr = &rep->rr_recv_wr;
1513                 ++count;
1514                 --needed;
1515         }
1516         if (!count)
1517                 goto out;
1518
1519         rc = ib_post_recv(r_xprt->rx_ia.ri_id->qp, wr,
1520                           (const struct ib_recv_wr **)&bad_wr);
1521         if (rc) {
1522                 for (wr = bad_wr; wr; wr = wr->next) {
1523                         struct rpcrdma_rep *rep;
1524
1525                         rep = container_of(wr, struct rpcrdma_rep, rr_recv_wr);
1526                         rpcrdma_recv_buffer_put(rep);
1527                         --count;
1528                 }
1529         }
1530         ep->rep_receive_count += count;
1531 out:
1532         trace_xprtrdma_post_recvs(r_xprt, count, rc);
1533 }