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1/*
2 * Copyright (c) 2006, 2019 Oracle and/or its affiliates. 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
8 * OpenIB.org BSD license below:
9 *
10 * Redistribution and use in source and binary forms, with or
11 * without modification, are permitted provided that the following
12 * conditions are met:
13 *
14 * - Redistributions of source code must retain the above
15 * copyright notice, this list of conditions and the following
16 * disclaimer.
17 *
18 * - Redistributions in binary form must reproduce the above
19 * copyright notice, this list of conditions and the following
20 * disclaimer in the documentation and/or other materials
21 * provided with the distribution.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30 * SOFTWARE.
31 *
32 */
33#include <linux/kernel.h>
34#include <linux/in.h>
35#include <linux/device.h>
36#include <linux/dmapool.h>
37#include <linux/ratelimit.h>
38
39#include "rds_single_path.h"
40#include "rds.h"
41#include "ib.h"
42#include "ib_mr.h"
43
44/*
45 * Convert IB-specific error message to RDS error message and call core
46 * completion handler.
47 */
48static void rds_ib_send_complete(struct rds_message *rm,
49 int wc_status,
50 void (*complete)(struct rds_message *rm, int status))
51{
52 int notify_status;
53
54 switch (wc_status) {
55 case IB_WC_WR_FLUSH_ERR:
56 return;
57
58 case IB_WC_SUCCESS:
59 notify_status = RDS_RDMA_SUCCESS;
60 break;
61
62 case IB_WC_REM_ACCESS_ERR:
63 notify_status = RDS_RDMA_REMOTE_ERROR;
64 break;
65
66 default:
67 notify_status = RDS_RDMA_OTHER_ERROR;
68 break;
69 }
70 complete(rm, notify_status);
71}
72
73static void rds_ib_send_unmap_data(struct rds_ib_connection *ic,
74 struct rm_data_op *op,
75 int wc_status)
76{
77 if (op->op_nents)
78 ib_dma_unmap_sg(ic->i_cm_id->device,
79 op->op_sg, op->op_nents,
80 DMA_TO_DEVICE);
81}
82
83static void rds_ib_send_unmap_rdma(struct rds_ib_connection *ic,
84 struct rm_rdma_op *op,
85 int wc_status)
86{
87 if (op->op_mapped) {
88 ib_dma_unmap_sg(ic->i_cm_id->device,
89 op->op_sg, op->op_nents,
90 op->op_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
91 op->op_mapped = 0;
92 }
93
94 /* If the user asked for a completion notification on this
95 * message, we can implement three different semantics:
96 * 1. Notify when we received the ACK on the RDS message
97 * that was queued with the RDMA. This provides reliable
98 * notification of RDMA status at the expense of a one-way
99 * packet delay.
100 * 2. Notify when the IB stack gives us the completion event for
101 * the RDMA operation.
102 * 3. Notify when the IB stack gives us the completion event for
103 * the accompanying RDS messages.
104 * Here, we implement approach #3. To implement approach #2,
105 * we would need to take an event for the rdma WR. To implement #1,
106 * don't call rds_rdma_send_complete at all, and fall back to the notify
107 * handling in the ACK processing code.
108 *
109 * Note: There's no need to explicitly sync any RDMA buffers using
110 * ib_dma_sync_sg_for_cpu - the completion for the RDMA
111 * operation itself unmapped the RDMA buffers, which takes care
112 * of synching.
113 */
114 rds_ib_send_complete(container_of(op, struct rds_message, rdma),
115 wc_status, rds_rdma_send_complete);
116
117 if (op->op_write)
118 rds_stats_add(s_send_rdma_bytes, op->op_bytes);
119 else
120 rds_stats_add(s_recv_rdma_bytes, op->op_bytes);
121}
122
123static void rds_ib_send_unmap_atomic(struct rds_ib_connection *ic,
124 struct rm_atomic_op *op,
125 int wc_status)
126{
127 /* unmap atomic recvbuf */
128 if (op->op_mapped) {
129 ib_dma_unmap_sg(ic->i_cm_id->device, op->op_sg, 1,
130 DMA_FROM_DEVICE);
131 op->op_mapped = 0;
132 }
133
134 rds_ib_send_complete(container_of(op, struct rds_message, atomic),
135 wc_status, rds_atomic_send_complete);
136
137 if (op->op_type == RDS_ATOMIC_TYPE_CSWP)
138 rds_ib_stats_inc(s_ib_atomic_cswp);
139 else
140 rds_ib_stats_inc(s_ib_atomic_fadd);
141}
142
143/*
144 * Unmap the resources associated with a struct send_work.
145 *
146 * Returns the rm for no good reason other than it is unobtainable
147 * other than by switching on wr.opcode, currently, and the caller,
148 * the event handler, needs it.
149 */
150static struct rds_message *rds_ib_send_unmap_op(struct rds_ib_connection *ic,
151 struct rds_ib_send_work *send,
152 int wc_status)
153{
154 struct rds_message *rm = NULL;
155
156 /* In the error case, wc.opcode sometimes contains garbage */
157 switch (send->s_wr.opcode) {
158 case IB_WR_SEND:
159 if (send->s_op) {
160 rm = container_of(send->s_op, struct rds_message, data);
161 rds_ib_send_unmap_data(ic, send->s_op, wc_status);
162 }
163 break;
164 case IB_WR_RDMA_WRITE:
165 case IB_WR_RDMA_READ:
166 if (send->s_op) {
167 rm = container_of(send->s_op, struct rds_message, rdma);
168 rds_ib_send_unmap_rdma(ic, send->s_op, wc_status);
169 }
170 break;
171 case IB_WR_ATOMIC_FETCH_AND_ADD:
172 case IB_WR_ATOMIC_CMP_AND_SWP:
173 if (send->s_op) {
174 rm = container_of(send->s_op, struct rds_message, atomic);
175 rds_ib_send_unmap_atomic(ic, send->s_op, wc_status);
176 }
177 break;
178 default:
179 printk_ratelimited(KERN_NOTICE
180 "RDS/IB: %s: unexpected opcode 0x%x in WR!\n",
181 __func__, send->s_wr.opcode);
182 break;
183 }
184
185 send->s_wr.opcode = 0xdead;
186
187 return rm;
188}
189
190void rds_ib_send_init_ring(struct rds_ib_connection *ic)
191{
192 struct rds_ib_send_work *send;
193 u32 i;
194
195 for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) {
196 struct ib_sge *sge;
197
198 send->s_op = NULL;
199
200 send->s_wr.wr_id = i;
201 send->s_wr.sg_list = send->s_sge;
202 send->s_wr.ex.imm_data = 0;
203
204 sge = &send->s_sge[0];
205 sge->addr = ic->i_send_hdrs_dma[i];
206
207 sge->length = sizeof(struct rds_header);
208 sge->lkey = ic->i_pd->local_dma_lkey;
209
210 send->s_sge[1].lkey = ic->i_pd->local_dma_lkey;
211 }
212}
213
214void rds_ib_send_clear_ring(struct rds_ib_connection *ic)
215{
216 struct rds_ib_send_work *send;
217 u32 i;
218
219 for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) {
220 if (send->s_op && send->s_wr.opcode != 0xdead)
221 rds_ib_send_unmap_op(ic, send, IB_WC_WR_FLUSH_ERR);
222 }
223}
224
225/*
226 * The only fast path caller always has a non-zero nr, so we don't
227 * bother testing nr before performing the atomic sub.
228 */
229static void rds_ib_sub_signaled(struct rds_ib_connection *ic, int nr)
230{
231 if ((atomic_sub_return(nr, &ic->i_signaled_sends) == 0) &&
232 waitqueue_active(&rds_ib_ring_empty_wait))
233 wake_up(&rds_ib_ring_empty_wait);
234 BUG_ON(atomic_read(&ic->i_signaled_sends) < 0);
235}
236
237/*
238 * The _oldest/_free ring operations here race cleanly with the alloc/unalloc
239 * operations performed in the send path. As the sender allocs and potentially
240 * unallocs the next free entry in the ring it doesn't alter which is
241 * the next to be freed, which is what this is concerned with.
242 */
243void rds_ib_send_cqe_handler(struct rds_ib_connection *ic, struct ib_wc *wc)
244{
245 struct rds_message *rm = NULL;
246 struct rds_connection *conn = ic->conn;
247 struct rds_ib_send_work *send;
248 u32 completed;
249 u32 oldest;
250 u32 i = 0;
251 int nr_sig = 0;
252
253
254 rdsdebug("wc wr_id 0x%llx status %u (%s) byte_len %u imm_data %u\n",
255 (unsigned long long)wc->wr_id, wc->status,
256 ib_wc_status_msg(wc->status), wc->byte_len,
257 be32_to_cpu(wc->ex.imm_data));
258 rds_ib_stats_inc(s_ib_tx_cq_event);
259
260 if (wc->wr_id == RDS_IB_ACK_WR_ID) {
261 if (time_after(jiffies, ic->i_ack_queued + HZ / 2))
262 rds_ib_stats_inc(s_ib_tx_stalled);
263 rds_ib_ack_send_complete(ic);
264 return;
265 }
266
267 oldest = rds_ib_ring_oldest(&ic->i_send_ring);
268
269 completed = rds_ib_ring_completed(&ic->i_send_ring, wc->wr_id, oldest);
270
271 for (i = 0; i < completed; i++) {
272 send = &ic->i_sends[oldest];
273 if (send->s_wr.send_flags & IB_SEND_SIGNALED)
274 nr_sig++;
275
276 rm = rds_ib_send_unmap_op(ic, send, wc->status);
277
278 if (time_after(jiffies, send->s_queued + HZ / 2))
279 rds_ib_stats_inc(s_ib_tx_stalled);
280
281 if (send->s_op) {
282 if (send->s_op == rm->m_final_op) {
283 /* If anyone waited for this message to get
284 * flushed out, wake them up now
285 */
286 rds_message_unmapped(rm);
287 }
288 rds_message_put(rm);
289 send->s_op = NULL;
290 }
291
292 oldest = (oldest + 1) % ic->i_send_ring.w_nr;
293 }
294
295 rds_ib_ring_free(&ic->i_send_ring, completed);
296 rds_ib_sub_signaled(ic, nr_sig);
297 nr_sig = 0;
298
299 if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags) ||
300 test_bit(0, &conn->c_map_queued))
301 queue_delayed_work(rds_wq, &conn->c_send_w, 0);
302
303 /* We expect errors as the qp is drained during shutdown */
304 if (wc->status != IB_WC_SUCCESS && rds_conn_up(conn)) {
305 rds_ib_conn_error(conn, "send completion on <%pI6c,%pI6c,%d> had status %u (%s), vendor err 0x%x, disconnecting and reconnecting\n",
306 &conn->c_laddr, &conn->c_faddr,
307 conn->c_tos, wc->status,
308 ib_wc_status_msg(wc->status), wc->vendor_err);
309 }
310}
311
312/*
313 * This is the main function for allocating credits when sending
314 * messages.
315 *
316 * Conceptually, we have two counters:
317 * - send credits: this tells us how many WRs we're allowed
318 * to submit without overruning the receiver's queue. For
319 * each SEND WR we post, we decrement this by one.
320 *
321 * - posted credits: this tells us how many WRs we recently
322 * posted to the receive queue. This value is transferred
323 * to the peer as a "credit update" in a RDS header field.
324 * Every time we transmit credits to the peer, we subtract
325 * the amount of transferred credits from this counter.
326 *
327 * It is essential that we avoid situations where both sides have
328 * exhausted their send credits, and are unable to send new credits
329 * to the peer. We achieve this by requiring that we send at least
330 * one credit update to the peer before exhausting our credits.
331 * When new credits arrive, we subtract one credit that is withheld
332 * until we've posted new buffers and are ready to transmit these
333 * credits (see rds_ib_send_add_credits below).
334 *
335 * The RDS send code is essentially single-threaded; rds_send_xmit
336 * sets RDS_IN_XMIT to ensure exclusive access to the send ring.
337 * However, the ACK sending code is independent and can race with
338 * message SENDs.
339 *
340 * In the send path, we need to update the counters for send credits
341 * and the counter of posted buffers atomically - when we use the
342 * last available credit, we cannot allow another thread to race us
343 * and grab the posted credits counter. Hence, we have to use a
344 * spinlock to protect the credit counter, or use atomics.
345 *
346 * Spinlocks shared between the send and the receive path are bad,
347 * because they create unnecessary delays. An early implementation
348 * using a spinlock showed a 5% degradation in throughput at some
349 * loads.
350 *
351 * This implementation avoids spinlocks completely, putting both
352 * counters into a single atomic, and updating that atomic using
353 * atomic_add (in the receive path, when receiving fresh credits),
354 * and using atomic_cmpxchg when updating the two counters.
355 */
356int rds_ib_send_grab_credits(struct rds_ib_connection *ic,
357 u32 wanted, u32 *adv_credits, int need_posted, int max_posted)
358{
359 unsigned int avail, posted, got = 0, advertise;
360 long oldval, newval;
361
362 *adv_credits = 0;
363 if (!ic->i_flowctl)
364 return wanted;
365
366try_again:
367 advertise = 0;
368 oldval = newval = atomic_read(&ic->i_credits);
369 posted = IB_GET_POST_CREDITS(oldval);
370 avail = IB_GET_SEND_CREDITS(oldval);
371
372 rdsdebug("wanted=%u credits=%u posted=%u\n",
373 wanted, avail, posted);
374
375 /* The last credit must be used to send a credit update. */
376 if (avail && !posted)
377 avail--;
378
379 if (avail < wanted) {
380 struct rds_connection *conn = ic->i_cm_id->context;
381
382 /* Oops, there aren't that many credits left! */
383 set_bit(RDS_LL_SEND_FULL, &conn->c_flags);
384 got = avail;
385 } else {
386 /* Sometimes you get what you want, lalala. */
387 got = wanted;
388 }
389 newval -= IB_SET_SEND_CREDITS(got);
390
391 /*
392 * If need_posted is non-zero, then the caller wants
393 * the posted regardless of whether any send credits are
394 * available.
395 */
396 if (posted && (got || need_posted)) {
397 advertise = min_t(unsigned int, posted, max_posted);
398 newval -= IB_SET_POST_CREDITS(advertise);
399 }
400
401 /* Finally bill everything */
402 if (atomic_cmpxchg(&ic->i_credits, oldval, newval) != oldval)
403 goto try_again;
404
405 *adv_credits = advertise;
406 return got;
407}
408
409void rds_ib_send_add_credits(struct rds_connection *conn, unsigned int credits)
410{
411 struct rds_ib_connection *ic = conn->c_transport_data;
412
413 if (credits == 0)
414 return;
415
416 rdsdebug("credits=%u current=%u%s\n",
417 credits,
418 IB_GET_SEND_CREDITS(atomic_read(&ic->i_credits)),
419 test_bit(RDS_LL_SEND_FULL, &conn->c_flags) ? ", ll_send_full" : "");
420
421 atomic_add(IB_SET_SEND_CREDITS(credits), &ic->i_credits);
422 if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags))
423 queue_delayed_work(rds_wq, &conn->c_send_w, 0);
424
425 WARN_ON(IB_GET_SEND_CREDITS(credits) >= 16384);
426
427 rds_ib_stats_inc(s_ib_rx_credit_updates);
428}
429
430void rds_ib_advertise_credits(struct rds_connection *conn, unsigned int posted)
431{
432 struct rds_ib_connection *ic = conn->c_transport_data;
433
434 if (posted == 0)
435 return;
436
437 atomic_add(IB_SET_POST_CREDITS(posted), &ic->i_credits);
438
439 /* Decide whether to send an update to the peer now.
440 * If we would send a credit update for every single buffer we
441 * post, we would end up with an ACK storm (ACK arrives,
442 * consumes buffer, we refill the ring, send ACK to remote
443 * advertising the newly posted buffer... ad inf)
444 *
445 * Performance pretty much depends on how often we send
446 * credit updates - too frequent updates mean lots of ACKs.
447 * Too infrequent updates, and the peer will run out of
448 * credits and has to throttle.
449 * For the time being, 16 seems to be a good compromise.
450 */
451 if (IB_GET_POST_CREDITS(atomic_read(&ic->i_credits)) >= 16)
452 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
453}
454
455static inline int rds_ib_set_wr_signal_state(struct rds_ib_connection *ic,
456 struct rds_ib_send_work *send,
457 bool notify)
458{
459 /*
460 * We want to delay signaling completions just enough to get
461 * the batching benefits but not so much that we create dead time
462 * on the wire.
463 */
464 if (ic->i_unsignaled_wrs-- == 0 || notify) {
465 ic->i_unsignaled_wrs = rds_ib_sysctl_max_unsig_wrs;
466 send->s_wr.send_flags |= IB_SEND_SIGNALED;
467 return 1;
468 }
469 return 0;
470}
471
472/*
473 * This can be called multiple times for a given message. The first time
474 * we see a message we map its scatterlist into the IB device so that
475 * we can provide that mapped address to the IB scatter gather entries
476 * in the IB work requests. We translate the scatterlist into a series
477 * of work requests that fragment the message. These work requests complete
478 * in order so we pass ownership of the message to the completion handler
479 * once we send the final fragment.
480 *
481 * The RDS core uses the c_send_lock to only enter this function once
482 * per connection. This makes sure that the tx ring alloc/unalloc pairs
483 * don't get out of sync and confuse the ring.
484 */
485int rds_ib_xmit(struct rds_connection *conn, struct rds_message *rm,
486 unsigned int hdr_off, unsigned int sg, unsigned int off)
487{
488 struct rds_ib_connection *ic = conn->c_transport_data;
489 struct ib_device *dev = ic->i_cm_id->device;
490 struct rds_ib_send_work *send = NULL;
491 struct rds_ib_send_work *first;
492 struct rds_ib_send_work *prev;
493 const struct ib_send_wr *failed_wr;
494 struct scatterlist *scat;
495 u32 pos;
496 u32 i;
497 u32 work_alloc;
498 u32 credit_alloc = 0;
499 u32 posted;
500 u32 adv_credits = 0;
501 int send_flags = 0;
502 int bytes_sent = 0;
503 int ret;
504 int flow_controlled = 0;
505 int nr_sig = 0;
506
507 BUG_ON(off % RDS_FRAG_SIZE);
508 BUG_ON(hdr_off != 0 && hdr_off != sizeof(struct rds_header));
509
510 /* Do not send cong updates to IB loopback */
511 if (conn->c_loopback
512 && rm->m_inc.i_hdr.h_flags & RDS_FLAG_CONG_BITMAP) {
513 rds_cong_map_updated(conn->c_fcong, ~(u64) 0);
514 scat = &rm->data.op_sg[sg];
515 ret = max_t(int, RDS_CONG_MAP_BYTES, scat->length);
516 return sizeof(struct rds_header) + ret;
517 }
518
519 /* FIXME we may overallocate here */
520 if (be32_to_cpu(rm->m_inc.i_hdr.h_len) == 0)
521 i = 1;
522 else
523 i = DIV_ROUND_UP(be32_to_cpu(rm->m_inc.i_hdr.h_len), RDS_FRAG_SIZE);
524
525 work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos);
526 if (work_alloc == 0) {
527 set_bit(RDS_LL_SEND_FULL, &conn->c_flags);
528 rds_ib_stats_inc(s_ib_tx_ring_full);
529 ret = -ENOMEM;
530 goto out;
531 }
532
533 if (ic->i_flowctl) {
534 credit_alloc = rds_ib_send_grab_credits(ic, work_alloc, &posted, 0, RDS_MAX_ADV_CREDIT);
535 adv_credits += posted;
536 if (credit_alloc < work_alloc) {
537 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - credit_alloc);
538 work_alloc = credit_alloc;
539 flow_controlled = 1;
540 }
541 if (work_alloc == 0) {
542 set_bit(RDS_LL_SEND_FULL, &conn->c_flags);
543 rds_ib_stats_inc(s_ib_tx_throttle);
544 ret = -ENOMEM;
545 goto out;
546 }
547 }
548
549 /* map the message the first time we see it */
550 if (!ic->i_data_op) {
551 if (rm->data.op_nents) {
552 rm->data.op_count = ib_dma_map_sg(dev,
553 rm->data.op_sg,
554 rm->data.op_nents,
555 DMA_TO_DEVICE);
556 rdsdebug("ic %p mapping rm %p: %d\n", ic, rm, rm->data.op_count);
557 if (rm->data.op_count == 0) {
558 rds_ib_stats_inc(s_ib_tx_sg_mapping_failure);
559 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
560 ret = -ENOMEM; /* XXX ? */
561 goto out;
562 }
563 } else {
564 rm->data.op_count = 0;
565 }
566
567 rds_message_addref(rm);
568 rm->data.op_dmasg = 0;
569 rm->data.op_dmaoff = 0;
570 ic->i_data_op = &rm->data;
571
572 /* Finalize the header */
573 if (test_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags))
574 rm->m_inc.i_hdr.h_flags |= RDS_FLAG_ACK_REQUIRED;
575 if (test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags))
576 rm->m_inc.i_hdr.h_flags |= RDS_FLAG_RETRANSMITTED;
577
578 /* If it has a RDMA op, tell the peer we did it. This is
579 * used by the peer to release use-once RDMA MRs. */
580 if (rm->rdma.op_active) {
581 struct rds_ext_header_rdma ext_hdr;
582
583 ext_hdr.h_rdma_rkey = cpu_to_be32(rm->rdma.op_rkey);
584 rds_message_add_extension(&rm->m_inc.i_hdr,
585 RDS_EXTHDR_RDMA, &ext_hdr, sizeof(ext_hdr));
586 }
587 if (rm->m_rdma_cookie) {
588 rds_message_add_rdma_dest_extension(&rm->m_inc.i_hdr,
589 rds_rdma_cookie_key(rm->m_rdma_cookie),
590 rds_rdma_cookie_offset(rm->m_rdma_cookie));
591 }
592
593 /* Note - rds_ib_piggyb_ack clears the ACK_REQUIRED bit, so
594 * we should not do this unless we have a chance of at least
595 * sticking the header into the send ring. Which is why we
596 * should call rds_ib_ring_alloc first. */
597 rm->m_inc.i_hdr.h_ack = cpu_to_be64(rds_ib_piggyb_ack(ic));
598 rds_message_make_checksum(&rm->m_inc.i_hdr);
599
600 /*
601 * Update adv_credits since we reset the ACK_REQUIRED bit.
602 */
603 if (ic->i_flowctl) {
604 rds_ib_send_grab_credits(ic, 0, &posted, 1, RDS_MAX_ADV_CREDIT - adv_credits);
605 adv_credits += posted;
606 BUG_ON(adv_credits > 255);
607 }
608 }
609
610 /* Sometimes you want to put a fence between an RDMA
611 * READ and the following SEND.
612 * We could either do this all the time
613 * or when requested by the user. Right now, we let
614 * the application choose.
615 */
616 if (rm->rdma.op_active && rm->rdma.op_fence)
617 send_flags = IB_SEND_FENCE;
618
619 /* Each frag gets a header. Msgs may be 0 bytes */
620 send = &ic->i_sends[pos];
621 first = send;
622 prev = NULL;
623 scat = &ic->i_data_op->op_sg[rm->data.op_dmasg];
624 i = 0;
625 do {
626 unsigned int len = 0;
627
628 /* Set up the header */
629 send->s_wr.send_flags = send_flags;
630 send->s_wr.opcode = IB_WR_SEND;
631 send->s_wr.num_sge = 1;
632 send->s_wr.next = NULL;
633 send->s_queued = jiffies;
634 send->s_op = NULL;
635
636 send->s_sge[0].addr = ic->i_send_hdrs_dma[pos];
637
638 send->s_sge[0].length = sizeof(struct rds_header);
639 send->s_sge[0].lkey = ic->i_pd->local_dma_lkey;
640
641 memcpy(ic->i_send_hdrs[pos], &rm->m_inc.i_hdr,
642 sizeof(struct rds_header));
643
644
645 /* Set up the data, if present */
646 if (i < work_alloc
647 && scat != &rm->data.op_sg[rm->data.op_count]) {
648 len = min(RDS_FRAG_SIZE,
649 sg_dma_len(scat) - rm->data.op_dmaoff);
650 send->s_wr.num_sge = 2;
651
652 send->s_sge[1].addr = sg_dma_address(scat);
653 send->s_sge[1].addr += rm->data.op_dmaoff;
654 send->s_sge[1].length = len;
655 send->s_sge[1].lkey = ic->i_pd->local_dma_lkey;
656
657 bytes_sent += len;
658 rm->data.op_dmaoff += len;
659 if (rm->data.op_dmaoff == sg_dma_len(scat)) {
660 scat++;
661 rm->data.op_dmasg++;
662 rm->data.op_dmaoff = 0;
663 }
664 }
665
666 rds_ib_set_wr_signal_state(ic, send, false);
667
668 /*
669 * Always signal the last one if we're stopping due to flow control.
670 */
671 if (ic->i_flowctl && flow_controlled && i == (work_alloc - 1)) {
672 rds_ib_set_wr_signal_state(ic, send, true);
673 send->s_wr.send_flags |= IB_SEND_SOLICITED;
674 }
675
676 if (send->s_wr.send_flags & IB_SEND_SIGNALED)
677 nr_sig++;
678
679 rdsdebug("send %p wr %p num_sge %u next %p\n", send,
680 &send->s_wr, send->s_wr.num_sge, send->s_wr.next);
681
682 if (ic->i_flowctl && adv_credits) {
683 struct rds_header *hdr = ic->i_send_hdrs[pos];
684
685 /* add credit and redo the header checksum */
686 hdr->h_credit = adv_credits;
687 rds_message_make_checksum(hdr);
688 adv_credits = 0;
689 rds_ib_stats_inc(s_ib_tx_credit_updates);
690 }
691
692 if (prev)
693 prev->s_wr.next = &send->s_wr;
694 prev = send;
695
696 pos = (pos + 1) % ic->i_send_ring.w_nr;
697 send = &ic->i_sends[pos];
698 i++;
699
700 } while (i < work_alloc
701 && scat != &rm->data.op_sg[rm->data.op_count]);
702
703 /* Account the RDS header in the number of bytes we sent, but just once.
704 * The caller has no concept of fragmentation. */
705 if (hdr_off == 0)
706 bytes_sent += sizeof(struct rds_header);
707
708 /* if we finished the message then send completion owns it */
709 if (scat == &rm->data.op_sg[rm->data.op_count]) {
710 prev->s_op = ic->i_data_op;
711 prev->s_wr.send_flags |= IB_SEND_SOLICITED;
712 if (!(prev->s_wr.send_flags & IB_SEND_SIGNALED))
713 nr_sig += rds_ib_set_wr_signal_state(ic, prev, true);
714 ic->i_data_op = NULL;
715 }
716
717 /* Put back wrs & credits we didn't use */
718 if (i < work_alloc) {
719 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i);
720 work_alloc = i;
721 }
722 if (ic->i_flowctl && i < credit_alloc)
723 rds_ib_send_add_credits(conn, credit_alloc - i);
724
725 if (nr_sig)
726 atomic_add(nr_sig, &ic->i_signaled_sends);
727
728 /* XXX need to worry about failed_wr and partial sends. */
729 failed_wr = &first->s_wr;
730 ret = ib_post_send(ic->i_cm_id->qp, &first->s_wr, &failed_wr);
731 rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic,
732 first, &first->s_wr, ret, failed_wr);
733 BUG_ON(failed_wr != &first->s_wr);
734 if (ret) {
735 printk(KERN_WARNING "RDS/IB: ib_post_send to %pI6c "
736 "returned %d\n", &conn->c_faddr, ret);
737 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
738 rds_ib_sub_signaled(ic, nr_sig);
739 if (prev->s_op) {
740 ic->i_data_op = prev->s_op;
741 prev->s_op = NULL;
742 }
743
744 rds_ib_conn_error(ic->conn, "ib_post_send failed\n");
745 goto out;
746 }
747
748 ret = bytes_sent;
749out:
750 BUG_ON(adv_credits);
751 return ret;
752}
753
754/*
755 * Issue atomic operation.
756 * A simplified version of the rdma case, we always map 1 SG, and
757 * only 8 bytes, for the return value from the atomic operation.
758 */
759int rds_ib_xmit_atomic(struct rds_connection *conn, struct rm_atomic_op *op)
760{
761 struct rds_ib_connection *ic = conn->c_transport_data;
762 struct rds_ib_send_work *send = NULL;
763 const struct ib_send_wr *failed_wr;
764 u32 pos;
765 u32 work_alloc;
766 int ret;
767 int nr_sig = 0;
768
769 work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, 1, &pos);
770 if (work_alloc != 1) {
771 rds_ib_stats_inc(s_ib_tx_ring_full);
772 ret = -ENOMEM;
773 goto out;
774 }
775
776 /* address of send request in ring */
777 send = &ic->i_sends[pos];
778 send->s_queued = jiffies;
779
780 if (op->op_type == RDS_ATOMIC_TYPE_CSWP) {
781 send->s_atomic_wr.wr.opcode = IB_WR_MASKED_ATOMIC_CMP_AND_SWP;
782 send->s_atomic_wr.compare_add = op->op_m_cswp.compare;
783 send->s_atomic_wr.swap = op->op_m_cswp.swap;
784 send->s_atomic_wr.compare_add_mask = op->op_m_cswp.compare_mask;
785 send->s_atomic_wr.swap_mask = op->op_m_cswp.swap_mask;
786 } else { /* FADD */
787 send->s_atomic_wr.wr.opcode = IB_WR_MASKED_ATOMIC_FETCH_AND_ADD;
788 send->s_atomic_wr.compare_add = op->op_m_fadd.add;
789 send->s_atomic_wr.swap = 0;
790 send->s_atomic_wr.compare_add_mask = op->op_m_fadd.nocarry_mask;
791 send->s_atomic_wr.swap_mask = 0;
792 }
793 send->s_wr.send_flags = 0;
794 nr_sig = rds_ib_set_wr_signal_state(ic, send, op->op_notify);
795 send->s_atomic_wr.wr.num_sge = 1;
796 send->s_atomic_wr.wr.next = NULL;
797 send->s_atomic_wr.remote_addr = op->op_remote_addr;
798 send->s_atomic_wr.rkey = op->op_rkey;
799 send->s_op = op;
800 rds_message_addref(container_of(send->s_op, struct rds_message, atomic));
801
802 /* map 8 byte retval buffer to the device */
803 ret = ib_dma_map_sg(ic->i_cm_id->device, op->op_sg, 1, DMA_FROM_DEVICE);
804 rdsdebug("ic %p mapping atomic op %p. mapped %d pg\n", ic, op, ret);
805 if (ret != 1) {
806 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
807 rds_ib_stats_inc(s_ib_tx_sg_mapping_failure);
808 ret = -ENOMEM; /* XXX ? */
809 goto out;
810 }
811
812 /* Convert our struct scatterlist to struct ib_sge */
813 send->s_sge[0].addr = sg_dma_address(op->op_sg);
814 send->s_sge[0].length = sg_dma_len(op->op_sg);
815 send->s_sge[0].lkey = ic->i_pd->local_dma_lkey;
816
817 rdsdebug("rva %Lx rpa %Lx len %u\n", op->op_remote_addr,
818 send->s_sge[0].addr, send->s_sge[0].length);
819
820 if (nr_sig)
821 atomic_add(nr_sig, &ic->i_signaled_sends);
822
823 failed_wr = &send->s_atomic_wr.wr;
824 ret = ib_post_send(ic->i_cm_id->qp, &send->s_atomic_wr.wr, &failed_wr);
825 rdsdebug("ic %p send %p (wr %p) ret %d wr %p\n", ic,
826 send, &send->s_atomic_wr, ret, failed_wr);
827 BUG_ON(failed_wr != &send->s_atomic_wr.wr);
828 if (ret) {
829 printk(KERN_WARNING "RDS/IB: atomic ib_post_send to %pI6c "
830 "returned %d\n", &conn->c_faddr, ret);
831 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
832 rds_ib_sub_signaled(ic, nr_sig);
833 goto out;
834 }
835
836 if (unlikely(failed_wr != &send->s_atomic_wr.wr)) {
837 printk(KERN_WARNING "RDS/IB: atomic ib_post_send() rc=%d, but failed_wqe updated!\n", ret);
838 BUG_ON(failed_wr != &send->s_atomic_wr.wr);
839 }
840
841out:
842 return ret;
843}
844
845int rds_ib_xmit_rdma(struct rds_connection *conn, struct rm_rdma_op *op)
846{
847 struct rds_ib_connection *ic = conn->c_transport_data;
848 struct rds_ib_send_work *send = NULL;
849 struct rds_ib_send_work *first;
850 struct rds_ib_send_work *prev;
851 const struct ib_send_wr *failed_wr;
852 struct scatterlist *scat;
853 unsigned long len;
854 u64 remote_addr = op->op_remote_addr;
855 u32 max_sge = ic->rds_ibdev->max_sge;
856 u32 pos;
857 u32 work_alloc;
858 u32 i;
859 u32 j;
860 int sent;
861 int ret;
862 int num_sge;
863 int nr_sig = 0;
864 u64 odp_addr = op->op_odp_addr;
865 u32 odp_lkey = 0;
866
867 /* map the op the first time we see it */
868 if (!op->op_odp_mr) {
869 if (!op->op_mapped) {
870 op->op_count =
871 ib_dma_map_sg(ic->i_cm_id->device, op->op_sg,
872 op->op_nents,
873 (op->op_write) ? DMA_TO_DEVICE :
874 DMA_FROM_DEVICE);
875 rdsdebug("ic %p mapping op %p: %d\n", ic, op,
876 op->op_count);
877 if (op->op_count == 0) {
878 rds_ib_stats_inc(s_ib_tx_sg_mapping_failure);
879 ret = -ENOMEM; /* XXX ? */
880 goto out;
881 }
882 op->op_mapped = 1;
883 }
884 } else {
885 op->op_count = op->op_nents;
886 odp_lkey = rds_ib_get_lkey(op->op_odp_mr->r_trans_private);
887 }
888
889 /*
890 * Instead of knowing how to return a partial rdma read/write we insist that there
891 * be enough work requests to send the entire message.
892 */
893 i = DIV_ROUND_UP(op->op_count, max_sge);
894
895 work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos);
896 if (work_alloc != i) {
897 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
898 rds_ib_stats_inc(s_ib_tx_ring_full);
899 ret = -ENOMEM;
900 goto out;
901 }
902
903 send = &ic->i_sends[pos];
904 first = send;
905 prev = NULL;
906 scat = &op->op_sg[0];
907 sent = 0;
908 num_sge = op->op_count;
909
910 for (i = 0; i < work_alloc && scat != &op->op_sg[op->op_count]; i++) {
911 send->s_wr.send_flags = 0;
912 send->s_queued = jiffies;
913 send->s_op = NULL;
914
915 if (!op->op_notify)
916 nr_sig += rds_ib_set_wr_signal_state(ic, send,
917 op->op_notify);
918
919 send->s_wr.opcode = op->op_write ? IB_WR_RDMA_WRITE : IB_WR_RDMA_READ;
920 send->s_rdma_wr.remote_addr = remote_addr;
921 send->s_rdma_wr.rkey = op->op_rkey;
922
923 if (num_sge > max_sge) {
924 send->s_rdma_wr.wr.num_sge = max_sge;
925 num_sge -= max_sge;
926 } else {
927 send->s_rdma_wr.wr.num_sge = num_sge;
928 }
929
930 send->s_rdma_wr.wr.next = NULL;
931
932 if (prev)
933 prev->s_rdma_wr.wr.next = &send->s_rdma_wr.wr;
934
935 for (j = 0; j < send->s_rdma_wr.wr.num_sge &&
936 scat != &op->op_sg[op->op_count]; j++) {
937 len = sg_dma_len(scat);
938 if (!op->op_odp_mr) {
939 send->s_sge[j].addr = sg_dma_address(scat);
940 send->s_sge[j].lkey = ic->i_pd->local_dma_lkey;
941 } else {
942 send->s_sge[j].addr = odp_addr;
943 send->s_sge[j].lkey = odp_lkey;
944 }
945 send->s_sge[j].length = len;
946
947 sent += len;
948 rdsdebug("ic %p sent %d remote_addr %llu\n", ic, sent, remote_addr);
949
950 remote_addr += len;
951 odp_addr += len;
952 scat++;
953 }
954
955 rdsdebug("send %p wr %p num_sge %u next %p\n", send,
956 &send->s_rdma_wr.wr,
957 send->s_rdma_wr.wr.num_sge,
958 send->s_rdma_wr.wr.next);
959
960 prev = send;
961 if (++send == &ic->i_sends[ic->i_send_ring.w_nr])
962 send = ic->i_sends;
963 }
964
965 /* give a reference to the last op */
966 if (scat == &op->op_sg[op->op_count]) {
967 prev->s_op = op;
968 rds_message_addref(container_of(op, struct rds_message, rdma));
969 }
970
971 if (i < work_alloc) {
972 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i);
973 work_alloc = i;
974 }
975
976 if (nr_sig)
977 atomic_add(nr_sig, &ic->i_signaled_sends);
978
979 failed_wr = &first->s_rdma_wr.wr;
980 ret = ib_post_send(ic->i_cm_id->qp, &first->s_rdma_wr.wr, &failed_wr);
981 rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic,
982 first, &first->s_rdma_wr.wr, ret, failed_wr);
983 BUG_ON(failed_wr != &first->s_rdma_wr.wr);
984 if (ret) {
985 printk(KERN_WARNING "RDS/IB: rdma ib_post_send to %pI6c "
986 "returned %d\n", &conn->c_faddr, ret);
987 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
988 rds_ib_sub_signaled(ic, nr_sig);
989 goto out;
990 }
991
992 if (unlikely(failed_wr != &first->s_rdma_wr.wr)) {
993 printk(KERN_WARNING "RDS/IB: ib_post_send() rc=%d, but failed_wqe updated!\n", ret);
994 BUG_ON(failed_wr != &first->s_rdma_wr.wr);
995 }
996
997
998out:
999 return ret;
1000}
1001
1002void rds_ib_xmit_path_complete(struct rds_conn_path *cp)
1003{
1004 struct rds_connection *conn = cp->cp_conn;
1005 struct rds_ib_connection *ic = conn->c_transport_data;
1006
1007 /* We may have a pending ACK or window update we were unable
1008 * to send previously (due to flow control). Try again. */
1009 rds_ib_attempt_ack(ic);
1010}
1/*
2 * Copyright (c) 2006, 2019 Oracle and/or its affiliates. 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
8 * OpenIB.org BSD license below:
9 *
10 * Redistribution and use in source and binary forms, with or
11 * without modification, are permitted provided that the following
12 * conditions are met:
13 *
14 * - Redistributions of source code must retain the above
15 * copyright notice, this list of conditions and the following
16 * disclaimer.
17 *
18 * - Redistributions in binary form must reproduce the above
19 * copyright notice, this list of conditions and the following
20 * disclaimer in the documentation and/or other materials
21 * provided with the distribution.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30 * SOFTWARE.
31 *
32 */
33#include <linux/kernel.h>
34#include <linux/in.h>
35#include <linux/device.h>
36#include <linux/dmapool.h>
37#include <linux/ratelimit.h>
38
39#include "rds_single_path.h"
40#include "rds.h"
41#include "ib.h"
42#include "ib_mr.h"
43
44/*
45 * Convert IB-specific error message to RDS error message and call core
46 * completion handler.
47 */
48static void rds_ib_send_complete(struct rds_message *rm,
49 int wc_status,
50 void (*complete)(struct rds_message *rm, int status))
51{
52 int notify_status;
53
54 switch (wc_status) {
55 case IB_WC_WR_FLUSH_ERR:
56 return;
57
58 case IB_WC_SUCCESS:
59 notify_status = RDS_RDMA_SUCCESS;
60 break;
61
62 case IB_WC_REM_ACCESS_ERR:
63 notify_status = RDS_RDMA_REMOTE_ERROR;
64 break;
65
66 default:
67 notify_status = RDS_RDMA_OTHER_ERROR;
68 break;
69 }
70 complete(rm, notify_status);
71}
72
73static void rds_ib_send_unmap_data(struct rds_ib_connection *ic,
74 struct rm_data_op *op,
75 int wc_status)
76{
77 if (op->op_nents)
78 ib_dma_unmap_sg(ic->i_cm_id->device,
79 op->op_sg, op->op_nents,
80 DMA_TO_DEVICE);
81}
82
83static void rds_ib_send_unmap_rdma(struct rds_ib_connection *ic,
84 struct rm_rdma_op *op,
85 int wc_status)
86{
87 if (op->op_mapped) {
88 ib_dma_unmap_sg(ic->i_cm_id->device,
89 op->op_sg, op->op_nents,
90 op->op_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
91 op->op_mapped = 0;
92 }
93
94 /* If the user asked for a completion notification on this
95 * message, we can implement three different semantics:
96 * 1. Notify when we received the ACK on the RDS message
97 * that was queued with the RDMA. This provides reliable
98 * notification of RDMA status at the expense of a one-way
99 * packet delay.
100 * 2. Notify when the IB stack gives us the completion event for
101 * the RDMA operation.
102 * 3. Notify when the IB stack gives us the completion event for
103 * the accompanying RDS messages.
104 * Here, we implement approach #3. To implement approach #2,
105 * we would need to take an event for the rdma WR. To implement #1,
106 * don't call rds_rdma_send_complete at all, and fall back to the notify
107 * handling in the ACK processing code.
108 *
109 * Note: There's no need to explicitly sync any RDMA buffers using
110 * ib_dma_sync_sg_for_cpu - the completion for the RDMA
111 * operation itself unmapped the RDMA buffers, which takes care
112 * of synching.
113 */
114 rds_ib_send_complete(container_of(op, struct rds_message, rdma),
115 wc_status, rds_rdma_send_complete);
116
117 if (op->op_write)
118 rds_stats_add(s_send_rdma_bytes, op->op_bytes);
119 else
120 rds_stats_add(s_recv_rdma_bytes, op->op_bytes);
121}
122
123static void rds_ib_send_unmap_atomic(struct rds_ib_connection *ic,
124 struct rm_atomic_op *op,
125 int wc_status)
126{
127 /* unmap atomic recvbuf */
128 if (op->op_mapped) {
129 ib_dma_unmap_sg(ic->i_cm_id->device, op->op_sg, 1,
130 DMA_FROM_DEVICE);
131 op->op_mapped = 0;
132 }
133
134 rds_ib_send_complete(container_of(op, struct rds_message, atomic),
135 wc_status, rds_atomic_send_complete);
136
137 if (op->op_type == RDS_ATOMIC_TYPE_CSWP)
138 rds_ib_stats_inc(s_ib_atomic_cswp);
139 else
140 rds_ib_stats_inc(s_ib_atomic_fadd);
141}
142
143/*
144 * Unmap the resources associated with a struct send_work.
145 *
146 * Returns the rm for no good reason other than it is unobtainable
147 * other than by switching on wr.opcode, currently, and the caller,
148 * the event handler, needs it.
149 */
150static struct rds_message *rds_ib_send_unmap_op(struct rds_ib_connection *ic,
151 struct rds_ib_send_work *send,
152 int wc_status)
153{
154 struct rds_message *rm = NULL;
155
156 /* In the error case, wc.opcode sometimes contains garbage */
157 switch (send->s_wr.opcode) {
158 case IB_WR_SEND:
159 if (send->s_op) {
160 rm = container_of(send->s_op, struct rds_message, data);
161 rds_ib_send_unmap_data(ic, send->s_op, wc_status);
162 }
163 break;
164 case IB_WR_RDMA_WRITE:
165 case IB_WR_RDMA_READ:
166 if (send->s_op) {
167 rm = container_of(send->s_op, struct rds_message, rdma);
168 rds_ib_send_unmap_rdma(ic, send->s_op, wc_status);
169 }
170 break;
171 case IB_WR_ATOMIC_FETCH_AND_ADD:
172 case IB_WR_ATOMIC_CMP_AND_SWP:
173 if (send->s_op) {
174 rm = container_of(send->s_op, struct rds_message, atomic);
175 rds_ib_send_unmap_atomic(ic, send->s_op, wc_status);
176 }
177 break;
178 default:
179 printk_ratelimited(KERN_NOTICE
180 "RDS/IB: %s: unexpected opcode 0x%x in WR!\n",
181 __func__, send->s_wr.opcode);
182 break;
183 }
184
185 send->s_wr.opcode = 0xdead;
186
187 return rm;
188}
189
190void rds_ib_send_init_ring(struct rds_ib_connection *ic)
191{
192 struct rds_ib_send_work *send;
193 u32 i;
194
195 for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) {
196 struct ib_sge *sge;
197
198 send->s_op = NULL;
199
200 send->s_wr.wr_id = i;
201 send->s_wr.sg_list = send->s_sge;
202 send->s_wr.ex.imm_data = 0;
203
204 sge = &send->s_sge[0];
205 sge->addr = ic->i_send_hdrs_dma[i];
206
207 sge->length = sizeof(struct rds_header);
208 sge->lkey = ic->i_pd->local_dma_lkey;
209
210 send->s_sge[1].lkey = ic->i_pd->local_dma_lkey;
211 }
212}
213
214void rds_ib_send_clear_ring(struct rds_ib_connection *ic)
215{
216 struct rds_ib_send_work *send;
217 u32 i;
218
219 for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) {
220 if (send->s_op && send->s_wr.opcode != 0xdead)
221 rds_ib_send_unmap_op(ic, send, IB_WC_WR_FLUSH_ERR);
222 }
223}
224
225/*
226 * The only fast path caller always has a non-zero nr, so we don't
227 * bother testing nr before performing the atomic sub.
228 */
229static void rds_ib_sub_signaled(struct rds_ib_connection *ic, int nr)
230{
231 if ((atomic_sub_return(nr, &ic->i_signaled_sends) == 0) &&
232 waitqueue_active(&rds_ib_ring_empty_wait))
233 wake_up(&rds_ib_ring_empty_wait);
234 BUG_ON(atomic_read(&ic->i_signaled_sends) < 0);
235}
236
237/*
238 * The _oldest/_free ring operations here race cleanly with the alloc/unalloc
239 * operations performed in the send path. As the sender allocs and potentially
240 * unallocs the next free entry in the ring it doesn't alter which is
241 * the next to be freed, which is what this is concerned with.
242 */
243void rds_ib_send_cqe_handler(struct rds_ib_connection *ic, struct ib_wc *wc)
244{
245 struct rds_message *rm = NULL;
246 struct rds_connection *conn = ic->conn;
247 struct rds_ib_send_work *send;
248 u32 completed;
249 u32 oldest;
250 u32 i = 0;
251 int nr_sig = 0;
252
253
254 rdsdebug("wc wr_id 0x%llx status %u (%s) byte_len %u imm_data %u\n",
255 (unsigned long long)wc->wr_id, wc->status,
256 ib_wc_status_msg(wc->status), wc->byte_len,
257 be32_to_cpu(wc->ex.imm_data));
258 rds_ib_stats_inc(s_ib_tx_cq_event);
259
260 if (wc->wr_id == RDS_IB_ACK_WR_ID) {
261 if (time_after(jiffies, ic->i_ack_queued + HZ / 2))
262 rds_ib_stats_inc(s_ib_tx_stalled);
263 rds_ib_ack_send_complete(ic);
264 return;
265 }
266
267 oldest = rds_ib_ring_oldest(&ic->i_send_ring);
268
269 completed = rds_ib_ring_completed(&ic->i_send_ring, wc->wr_id, oldest);
270
271 for (i = 0; i < completed; i++) {
272 send = &ic->i_sends[oldest];
273 if (send->s_wr.send_flags & IB_SEND_SIGNALED)
274 nr_sig++;
275
276 rm = rds_ib_send_unmap_op(ic, send, wc->status);
277
278 if (time_after(jiffies, send->s_queued + HZ / 2))
279 rds_ib_stats_inc(s_ib_tx_stalled);
280
281 if (send->s_op) {
282 if (send->s_op == rm->m_final_op) {
283 /* If anyone waited for this message to get
284 * flushed out, wake them up now
285 */
286 rds_message_unmapped(rm);
287 }
288 rds_message_put(rm);
289 send->s_op = NULL;
290 }
291
292 oldest = (oldest + 1) % ic->i_send_ring.w_nr;
293 }
294
295 rds_ib_ring_free(&ic->i_send_ring, completed);
296 rds_ib_sub_signaled(ic, nr_sig);
297
298 if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags) ||
299 test_bit(0, &conn->c_map_queued))
300 queue_delayed_work(rds_wq, &conn->c_send_w, 0);
301
302 /* We expect errors as the qp is drained during shutdown */
303 if (wc->status != IB_WC_SUCCESS && rds_conn_up(conn)) {
304 rds_ib_conn_error(conn, "send completion on <%pI6c,%pI6c,%d> had status %u (%s), vendor err 0x%x, disconnecting and reconnecting\n",
305 &conn->c_laddr, &conn->c_faddr,
306 conn->c_tos, wc->status,
307 ib_wc_status_msg(wc->status), wc->vendor_err);
308 }
309}
310
311/*
312 * This is the main function for allocating credits when sending
313 * messages.
314 *
315 * Conceptually, we have two counters:
316 * - send credits: this tells us how many WRs we're allowed
317 * to submit without overruning the receiver's queue. For
318 * each SEND WR we post, we decrement this by one.
319 *
320 * - posted credits: this tells us how many WRs we recently
321 * posted to the receive queue. This value is transferred
322 * to the peer as a "credit update" in a RDS header field.
323 * Every time we transmit credits to the peer, we subtract
324 * the amount of transferred credits from this counter.
325 *
326 * It is essential that we avoid situations where both sides have
327 * exhausted their send credits, and are unable to send new credits
328 * to the peer. We achieve this by requiring that we send at least
329 * one credit update to the peer before exhausting our credits.
330 * When new credits arrive, we subtract one credit that is withheld
331 * until we've posted new buffers and are ready to transmit these
332 * credits (see rds_ib_send_add_credits below).
333 *
334 * The RDS send code is essentially single-threaded; rds_send_xmit
335 * sets RDS_IN_XMIT to ensure exclusive access to the send ring.
336 * However, the ACK sending code is independent and can race with
337 * message SENDs.
338 *
339 * In the send path, we need to update the counters for send credits
340 * and the counter of posted buffers atomically - when we use the
341 * last available credit, we cannot allow another thread to race us
342 * and grab the posted credits counter. Hence, we have to use a
343 * spinlock to protect the credit counter, or use atomics.
344 *
345 * Spinlocks shared between the send and the receive path are bad,
346 * because they create unnecessary delays. An early implementation
347 * using a spinlock showed a 5% degradation in throughput at some
348 * loads.
349 *
350 * This implementation avoids spinlocks completely, putting both
351 * counters into a single atomic, and updating that atomic using
352 * atomic_add (in the receive path, when receiving fresh credits),
353 * and using atomic_cmpxchg when updating the two counters.
354 */
355int rds_ib_send_grab_credits(struct rds_ib_connection *ic,
356 u32 wanted, u32 *adv_credits, int need_posted, int max_posted)
357{
358 unsigned int avail, posted, got = 0, advertise;
359 long oldval, newval;
360
361 *adv_credits = 0;
362 if (!ic->i_flowctl)
363 return wanted;
364
365try_again:
366 advertise = 0;
367 oldval = newval = atomic_read(&ic->i_credits);
368 posted = IB_GET_POST_CREDITS(oldval);
369 avail = IB_GET_SEND_CREDITS(oldval);
370
371 rdsdebug("wanted=%u credits=%u posted=%u\n",
372 wanted, avail, posted);
373
374 /* The last credit must be used to send a credit update. */
375 if (avail && !posted)
376 avail--;
377
378 if (avail < wanted) {
379 struct rds_connection *conn = ic->i_cm_id->context;
380
381 /* Oops, there aren't that many credits left! */
382 set_bit(RDS_LL_SEND_FULL, &conn->c_flags);
383 got = avail;
384 } else {
385 /* Sometimes you get what you want, lalala. */
386 got = wanted;
387 }
388 newval -= IB_SET_SEND_CREDITS(got);
389
390 /*
391 * If need_posted is non-zero, then the caller wants
392 * the posted regardless of whether any send credits are
393 * available.
394 */
395 if (posted && (got || need_posted)) {
396 advertise = min_t(unsigned int, posted, max_posted);
397 newval -= IB_SET_POST_CREDITS(advertise);
398 }
399
400 /* Finally bill everything */
401 if (atomic_cmpxchg(&ic->i_credits, oldval, newval) != oldval)
402 goto try_again;
403
404 *adv_credits = advertise;
405 return got;
406}
407
408void rds_ib_send_add_credits(struct rds_connection *conn, unsigned int credits)
409{
410 struct rds_ib_connection *ic = conn->c_transport_data;
411
412 if (credits == 0)
413 return;
414
415 rdsdebug("credits=%u current=%u%s\n",
416 credits,
417 IB_GET_SEND_CREDITS(atomic_read(&ic->i_credits)),
418 test_bit(RDS_LL_SEND_FULL, &conn->c_flags) ? ", ll_send_full" : "");
419
420 atomic_add(IB_SET_SEND_CREDITS(credits), &ic->i_credits);
421 if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags))
422 queue_delayed_work(rds_wq, &conn->c_send_w, 0);
423
424 WARN_ON(IB_GET_SEND_CREDITS(credits) >= 16384);
425
426 rds_ib_stats_inc(s_ib_rx_credit_updates);
427}
428
429void rds_ib_advertise_credits(struct rds_connection *conn, unsigned int posted)
430{
431 struct rds_ib_connection *ic = conn->c_transport_data;
432
433 if (posted == 0)
434 return;
435
436 atomic_add(IB_SET_POST_CREDITS(posted), &ic->i_credits);
437
438 /* Decide whether to send an update to the peer now.
439 * If we would send a credit update for every single buffer we
440 * post, we would end up with an ACK storm (ACK arrives,
441 * consumes buffer, we refill the ring, send ACK to remote
442 * advertising the newly posted buffer... ad inf)
443 *
444 * Performance pretty much depends on how often we send
445 * credit updates - too frequent updates mean lots of ACKs.
446 * Too infrequent updates, and the peer will run out of
447 * credits and has to throttle.
448 * For the time being, 16 seems to be a good compromise.
449 */
450 if (IB_GET_POST_CREDITS(atomic_read(&ic->i_credits)) >= 16)
451 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
452}
453
454static inline int rds_ib_set_wr_signal_state(struct rds_ib_connection *ic,
455 struct rds_ib_send_work *send,
456 bool notify)
457{
458 /*
459 * We want to delay signaling completions just enough to get
460 * the batching benefits but not so much that we create dead time
461 * on the wire.
462 */
463 if (ic->i_unsignaled_wrs-- == 0 || notify) {
464 ic->i_unsignaled_wrs = rds_ib_sysctl_max_unsig_wrs;
465 send->s_wr.send_flags |= IB_SEND_SIGNALED;
466 return 1;
467 }
468 return 0;
469}
470
471/*
472 * This can be called multiple times for a given message. The first time
473 * we see a message we map its scatterlist into the IB device so that
474 * we can provide that mapped address to the IB scatter gather entries
475 * in the IB work requests. We translate the scatterlist into a series
476 * of work requests that fragment the message. These work requests complete
477 * in order so we pass ownership of the message to the completion handler
478 * once we send the final fragment.
479 *
480 * The RDS core uses the c_send_lock to only enter this function once
481 * per connection. This makes sure that the tx ring alloc/unalloc pairs
482 * don't get out of sync and confuse the ring.
483 */
484int rds_ib_xmit(struct rds_connection *conn, struct rds_message *rm,
485 unsigned int hdr_off, unsigned int sg, unsigned int off)
486{
487 struct rds_ib_connection *ic = conn->c_transport_data;
488 struct ib_device *dev = ic->i_cm_id->device;
489 struct rds_ib_send_work *send = NULL;
490 struct rds_ib_send_work *first;
491 struct rds_ib_send_work *prev;
492 const struct ib_send_wr *failed_wr;
493 struct scatterlist *scat;
494 u32 pos;
495 u32 i;
496 u32 work_alloc;
497 u32 credit_alloc = 0;
498 u32 posted;
499 u32 adv_credits = 0;
500 int send_flags = 0;
501 int bytes_sent = 0;
502 int ret;
503 int flow_controlled = 0;
504 int nr_sig = 0;
505
506 BUG_ON(off % RDS_FRAG_SIZE);
507 BUG_ON(hdr_off != 0 && hdr_off != sizeof(struct rds_header));
508
509 /* Do not send cong updates to IB loopback */
510 if (conn->c_loopback
511 && rm->m_inc.i_hdr.h_flags & RDS_FLAG_CONG_BITMAP) {
512 rds_cong_map_updated(conn->c_fcong, ~(u64) 0);
513 scat = &rm->data.op_sg[sg];
514 ret = max_t(int, RDS_CONG_MAP_BYTES, scat->length);
515 return sizeof(struct rds_header) + ret;
516 }
517
518 /* FIXME we may overallocate here */
519 if (be32_to_cpu(rm->m_inc.i_hdr.h_len) == 0)
520 i = 1;
521 else
522 i = DIV_ROUND_UP(be32_to_cpu(rm->m_inc.i_hdr.h_len), RDS_FRAG_SIZE);
523
524 work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos);
525 if (work_alloc == 0) {
526 set_bit(RDS_LL_SEND_FULL, &conn->c_flags);
527 rds_ib_stats_inc(s_ib_tx_ring_full);
528 ret = -ENOMEM;
529 goto out;
530 }
531
532 if (ic->i_flowctl) {
533 credit_alloc = rds_ib_send_grab_credits(ic, work_alloc, &posted, 0, RDS_MAX_ADV_CREDIT);
534 adv_credits += posted;
535 if (credit_alloc < work_alloc) {
536 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - credit_alloc);
537 work_alloc = credit_alloc;
538 flow_controlled = 1;
539 }
540 if (work_alloc == 0) {
541 set_bit(RDS_LL_SEND_FULL, &conn->c_flags);
542 rds_ib_stats_inc(s_ib_tx_throttle);
543 ret = -ENOMEM;
544 goto out;
545 }
546 }
547
548 /* map the message the first time we see it */
549 if (!ic->i_data_op) {
550 if (rm->data.op_nents) {
551 rm->data.op_count = ib_dma_map_sg(dev,
552 rm->data.op_sg,
553 rm->data.op_nents,
554 DMA_TO_DEVICE);
555 rdsdebug("ic %p mapping rm %p: %d\n", ic, rm, rm->data.op_count);
556 if (rm->data.op_count == 0) {
557 rds_ib_stats_inc(s_ib_tx_sg_mapping_failure);
558 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
559 ret = -ENOMEM; /* XXX ? */
560 goto out;
561 }
562 } else {
563 rm->data.op_count = 0;
564 }
565
566 rds_message_addref(rm);
567 rm->data.op_dmasg = 0;
568 rm->data.op_dmaoff = 0;
569 ic->i_data_op = &rm->data;
570
571 /* Finalize the header */
572 if (test_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags))
573 rm->m_inc.i_hdr.h_flags |= RDS_FLAG_ACK_REQUIRED;
574 if (test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags))
575 rm->m_inc.i_hdr.h_flags |= RDS_FLAG_RETRANSMITTED;
576
577 /* If it has a RDMA op, tell the peer we did it. This is
578 * used by the peer to release use-once RDMA MRs. */
579 if (rm->rdma.op_active) {
580 struct rds_ext_header_rdma ext_hdr;
581
582 ext_hdr.h_rdma_rkey = cpu_to_be32(rm->rdma.op_rkey);
583 rds_message_add_extension(&rm->m_inc.i_hdr,
584 RDS_EXTHDR_RDMA, &ext_hdr, sizeof(ext_hdr));
585 }
586 if (rm->m_rdma_cookie) {
587 rds_message_add_rdma_dest_extension(&rm->m_inc.i_hdr,
588 rds_rdma_cookie_key(rm->m_rdma_cookie),
589 rds_rdma_cookie_offset(rm->m_rdma_cookie));
590 }
591
592 /* Note - rds_ib_piggyb_ack clears the ACK_REQUIRED bit, so
593 * we should not do this unless we have a chance of at least
594 * sticking the header into the send ring. Which is why we
595 * should call rds_ib_ring_alloc first. */
596 rm->m_inc.i_hdr.h_ack = cpu_to_be64(rds_ib_piggyb_ack(ic));
597 rds_message_make_checksum(&rm->m_inc.i_hdr);
598
599 /*
600 * Update adv_credits since we reset the ACK_REQUIRED bit.
601 */
602 if (ic->i_flowctl) {
603 rds_ib_send_grab_credits(ic, 0, &posted, 1, RDS_MAX_ADV_CREDIT - adv_credits);
604 adv_credits += posted;
605 BUG_ON(adv_credits > 255);
606 }
607 }
608
609 /* Sometimes you want to put a fence between an RDMA
610 * READ and the following SEND.
611 * We could either do this all the time
612 * or when requested by the user. Right now, we let
613 * the application choose.
614 */
615 if (rm->rdma.op_active && rm->rdma.op_fence)
616 send_flags = IB_SEND_FENCE;
617
618 /* Each frag gets a header. Msgs may be 0 bytes */
619 send = &ic->i_sends[pos];
620 first = send;
621 prev = NULL;
622 scat = &ic->i_data_op->op_sg[rm->data.op_dmasg];
623 i = 0;
624 do {
625 unsigned int len = 0;
626
627 /* Set up the header */
628 send->s_wr.send_flags = send_flags;
629 send->s_wr.opcode = IB_WR_SEND;
630 send->s_wr.num_sge = 1;
631 send->s_wr.next = NULL;
632 send->s_queued = jiffies;
633 send->s_op = NULL;
634
635 send->s_sge[0].addr = ic->i_send_hdrs_dma[pos];
636
637 send->s_sge[0].length = sizeof(struct rds_header);
638 send->s_sge[0].lkey = ic->i_pd->local_dma_lkey;
639
640 ib_dma_sync_single_for_cpu(ic->rds_ibdev->dev,
641 ic->i_send_hdrs_dma[pos],
642 sizeof(struct rds_header),
643 DMA_TO_DEVICE);
644 memcpy(ic->i_send_hdrs[pos], &rm->m_inc.i_hdr,
645 sizeof(struct rds_header));
646
647
648 /* Set up the data, if present */
649 if (i < work_alloc
650 && scat != &rm->data.op_sg[rm->data.op_count]) {
651 len = min(RDS_FRAG_SIZE,
652 sg_dma_len(scat) - rm->data.op_dmaoff);
653 send->s_wr.num_sge = 2;
654
655 send->s_sge[1].addr = sg_dma_address(scat);
656 send->s_sge[1].addr += rm->data.op_dmaoff;
657 send->s_sge[1].length = len;
658 send->s_sge[1].lkey = ic->i_pd->local_dma_lkey;
659
660 bytes_sent += len;
661 rm->data.op_dmaoff += len;
662 if (rm->data.op_dmaoff == sg_dma_len(scat)) {
663 scat++;
664 rm->data.op_dmasg++;
665 rm->data.op_dmaoff = 0;
666 }
667 }
668
669 rds_ib_set_wr_signal_state(ic, send, false);
670
671 /*
672 * Always signal the last one if we're stopping due to flow control.
673 */
674 if (ic->i_flowctl && flow_controlled && i == (work_alloc - 1)) {
675 rds_ib_set_wr_signal_state(ic, send, true);
676 send->s_wr.send_flags |= IB_SEND_SOLICITED;
677 }
678
679 if (send->s_wr.send_flags & IB_SEND_SIGNALED)
680 nr_sig++;
681
682 rdsdebug("send %p wr %p num_sge %u next %p\n", send,
683 &send->s_wr, send->s_wr.num_sge, send->s_wr.next);
684
685 if (ic->i_flowctl && adv_credits) {
686 struct rds_header *hdr = ic->i_send_hdrs[pos];
687
688 /* add credit and redo the header checksum */
689 hdr->h_credit = adv_credits;
690 rds_message_make_checksum(hdr);
691 adv_credits = 0;
692 rds_ib_stats_inc(s_ib_tx_credit_updates);
693 }
694 ib_dma_sync_single_for_device(ic->rds_ibdev->dev,
695 ic->i_send_hdrs_dma[pos],
696 sizeof(struct rds_header),
697 DMA_TO_DEVICE);
698
699 if (prev)
700 prev->s_wr.next = &send->s_wr;
701 prev = send;
702
703 pos = (pos + 1) % ic->i_send_ring.w_nr;
704 send = &ic->i_sends[pos];
705 i++;
706
707 } while (i < work_alloc
708 && scat != &rm->data.op_sg[rm->data.op_count]);
709
710 /* Account the RDS header in the number of bytes we sent, but just once.
711 * The caller has no concept of fragmentation. */
712 if (hdr_off == 0)
713 bytes_sent += sizeof(struct rds_header);
714
715 /* if we finished the message then send completion owns it */
716 if (scat == &rm->data.op_sg[rm->data.op_count]) {
717 prev->s_op = ic->i_data_op;
718 prev->s_wr.send_flags |= IB_SEND_SOLICITED;
719 if (!(prev->s_wr.send_flags & IB_SEND_SIGNALED))
720 nr_sig += rds_ib_set_wr_signal_state(ic, prev, true);
721 ic->i_data_op = NULL;
722 }
723
724 /* Put back wrs & credits we didn't use */
725 if (i < work_alloc) {
726 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i);
727 work_alloc = i;
728 }
729 if (ic->i_flowctl && i < credit_alloc)
730 rds_ib_send_add_credits(conn, credit_alloc - i);
731
732 if (nr_sig)
733 atomic_add(nr_sig, &ic->i_signaled_sends);
734
735 /* XXX need to worry about failed_wr and partial sends. */
736 failed_wr = &first->s_wr;
737 ret = ib_post_send(ic->i_cm_id->qp, &first->s_wr, &failed_wr);
738 rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic,
739 first, &first->s_wr, ret, failed_wr);
740 BUG_ON(failed_wr != &first->s_wr);
741 if (ret) {
742 printk(KERN_WARNING "RDS/IB: ib_post_send to %pI6c "
743 "returned %d\n", &conn->c_faddr, ret);
744 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
745 rds_ib_sub_signaled(ic, nr_sig);
746 if (prev->s_op) {
747 ic->i_data_op = prev->s_op;
748 prev->s_op = NULL;
749 }
750
751 rds_ib_conn_error(ic->conn, "ib_post_send failed\n");
752 goto out;
753 }
754
755 ret = bytes_sent;
756out:
757 BUG_ON(adv_credits);
758 return ret;
759}
760
761/*
762 * Issue atomic operation.
763 * A simplified version of the rdma case, we always map 1 SG, and
764 * only 8 bytes, for the return value from the atomic operation.
765 */
766int rds_ib_xmit_atomic(struct rds_connection *conn, struct rm_atomic_op *op)
767{
768 struct rds_ib_connection *ic = conn->c_transport_data;
769 struct rds_ib_send_work *send = NULL;
770 const struct ib_send_wr *failed_wr;
771 u32 pos;
772 u32 work_alloc;
773 int ret;
774 int nr_sig = 0;
775
776 work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, 1, &pos);
777 if (work_alloc != 1) {
778 rds_ib_stats_inc(s_ib_tx_ring_full);
779 ret = -ENOMEM;
780 goto out;
781 }
782
783 /* address of send request in ring */
784 send = &ic->i_sends[pos];
785 send->s_queued = jiffies;
786
787 if (op->op_type == RDS_ATOMIC_TYPE_CSWP) {
788 send->s_atomic_wr.wr.opcode = IB_WR_MASKED_ATOMIC_CMP_AND_SWP;
789 send->s_atomic_wr.compare_add = op->op_m_cswp.compare;
790 send->s_atomic_wr.swap = op->op_m_cswp.swap;
791 send->s_atomic_wr.compare_add_mask = op->op_m_cswp.compare_mask;
792 send->s_atomic_wr.swap_mask = op->op_m_cswp.swap_mask;
793 } else { /* FADD */
794 send->s_atomic_wr.wr.opcode = IB_WR_MASKED_ATOMIC_FETCH_AND_ADD;
795 send->s_atomic_wr.compare_add = op->op_m_fadd.add;
796 send->s_atomic_wr.swap = 0;
797 send->s_atomic_wr.compare_add_mask = op->op_m_fadd.nocarry_mask;
798 send->s_atomic_wr.swap_mask = 0;
799 }
800 send->s_wr.send_flags = 0;
801 nr_sig = rds_ib_set_wr_signal_state(ic, send, op->op_notify);
802 send->s_atomic_wr.wr.num_sge = 1;
803 send->s_atomic_wr.wr.next = NULL;
804 send->s_atomic_wr.remote_addr = op->op_remote_addr;
805 send->s_atomic_wr.rkey = op->op_rkey;
806 send->s_op = op;
807 rds_message_addref(container_of(send->s_op, struct rds_message, atomic));
808
809 /* map 8 byte retval buffer to the device */
810 ret = ib_dma_map_sg(ic->i_cm_id->device, op->op_sg, 1, DMA_FROM_DEVICE);
811 rdsdebug("ic %p mapping atomic op %p. mapped %d pg\n", ic, op, ret);
812 if (ret != 1) {
813 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
814 rds_ib_stats_inc(s_ib_tx_sg_mapping_failure);
815 ret = -ENOMEM; /* XXX ? */
816 goto out;
817 }
818
819 /* Convert our struct scatterlist to struct ib_sge */
820 send->s_sge[0].addr = sg_dma_address(op->op_sg);
821 send->s_sge[0].length = sg_dma_len(op->op_sg);
822 send->s_sge[0].lkey = ic->i_pd->local_dma_lkey;
823
824 rdsdebug("rva %Lx rpa %Lx len %u\n", op->op_remote_addr,
825 send->s_sge[0].addr, send->s_sge[0].length);
826
827 if (nr_sig)
828 atomic_add(nr_sig, &ic->i_signaled_sends);
829
830 failed_wr = &send->s_atomic_wr.wr;
831 ret = ib_post_send(ic->i_cm_id->qp, &send->s_atomic_wr.wr, &failed_wr);
832 rdsdebug("ic %p send %p (wr %p) ret %d wr %p\n", ic,
833 send, &send->s_atomic_wr, ret, failed_wr);
834 BUG_ON(failed_wr != &send->s_atomic_wr.wr);
835 if (ret) {
836 printk(KERN_WARNING "RDS/IB: atomic ib_post_send to %pI6c "
837 "returned %d\n", &conn->c_faddr, ret);
838 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
839 rds_ib_sub_signaled(ic, nr_sig);
840 goto out;
841 }
842
843 if (unlikely(failed_wr != &send->s_atomic_wr.wr)) {
844 printk(KERN_WARNING "RDS/IB: atomic ib_post_send() rc=%d, but failed_wqe updated!\n", ret);
845 BUG_ON(failed_wr != &send->s_atomic_wr.wr);
846 }
847
848out:
849 return ret;
850}
851
852int rds_ib_xmit_rdma(struct rds_connection *conn, struct rm_rdma_op *op)
853{
854 struct rds_ib_connection *ic = conn->c_transport_data;
855 struct rds_ib_send_work *send = NULL;
856 struct rds_ib_send_work *first;
857 struct rds_ib_send_work *prev;
858 const struct ib_send_wr *failed_wr;
859 struct scatterlist *scat;
860 unsigned long len;
861 u64 remote_addr = op->op_remote_addr;
862 u32 max_sge = ic->rds_ibdev->max_sge;
863 u32 pos;
864 u32 work_alloc;
865 u32 i;
866 u32 j;
867 int sent;
868 int ret;
869 int num_sge;
870 int nr_sig = 0;
871 u64 odp_addr = op->op_odp_addr;
872 u32 odp_lkey = 0;
873
874 /* map the op the first time we see it */
875 if (!op->op_odp_mr) {
876 if (!op->op_mapped) {
877 op->op_count =
878 ib_dma_map_sg(ic->i_cm_id->device, op->op_sg,
879 op->op_nents,
880 (op->op_write) ? DMA_TO_DEVICE :
881 DMA_FROM_DEVICE);
882 rdsdebug("ic %p mapping op %p: %d\n", ic, op,
883 op->op_count);
884 if (op->op_count == 0) {
885 rds_ib_stats_inc(s_ib_tx_sg_mapping_failure);
886 ret = -ENOMEM; /* XXX ? */
887 goto out;
888 }
889 op->op_mapped = 1;
890 }
891 } else {
892 op->op_count = op->op_nents;
893 odp_lkey = rds_ib_get_lkey(op->op_odp_mr->r_trans_private);
894 }
895
896 /*
897 * Instead of knowing how to return a partial rdma read/write we insist that there
898 * be enough work requests to send the entire message.
899 */
900 i = DIV_ROUND_UP(op->op_count, max_sge);
901
902 work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos);
903 if (work_alloc != i) {
904 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
905 rds_ib_stats_inc(s_ib_tx_ring_full);
906 ret = -ENOMEM;
907 goto out;
908 }
909
910 send = &ic->i_sends[pos];
911 first = send;
912 prev = NULL;
913 scat = &op->op_sg[0];
914 sent = 0;
915 num_sge = op->op_count;
916
917 for (i = 0; i < work_alloc && scat != &op->op_sg[op->op_count]; i++) {
918 send->s_wr.send_flags = 0;
919 send->s_queued = jiffies;
920 send->s_op = NULL;
921
922 if (!op->op_notify)
923 nr_sig += rds_ib_set_wr_signal_state(ic, send,
924 op->op_notify);
925
926 send->s_wr.opcode = op->op_write ? IB_WR_RDMA_WRITE : IB_WR_RDMA_READ;
927 send->s_rdma_wr.remote_addr = remote_addr;
928 send->s_rdma_wr.rkey = op->op_rkey;
929
930 if (num_sge > max_sge) {
931 send->s_rdma_wr.wr.num_sge = max_sge;
932 num_sge -= max_sge;
933 } else {
934 send->s_rdma_wr.wr.num_sge = num_sge;
935 }
936
937 send->s_rdma_wr.wr.next = NULL;
938
939 if (prev)
940 prev->s_rdma_wr.wr.next = &send->s_rdma_wr.wr;
941
942 for (j = 0; j < send->s_rdma_wr.wr.num_sge &&
943 scat != &op->op_sg[op->op_count]; j++) {
944 len = sg_dma_len(scat);
945 if (!op->op_odp_mr) {
946 send->s_sge[j].addr = sg_dma_address(scat);
947 send->s_sge[j].lkey = ic->i_pd->local_dma_lkey;
948 } else {
949 send->s_sge[j].addr = odp_addr;
950 send->s_sge[j].lkey = odp_lkey;
951 }
952 send->s_sge[j].length = len;
953
954 sent += len;
955 rdsdebug("ic %p sent %d remote_addr %llu\n", ic, sent, remote_addr);
956
957 remote_addr += len;
958 odp_addr += len;
959 scat++;
960 }
961
962 rdsdebug("send %p wr %p num_sge %u next %p\n", send,
963 &send->s_rdma_wr.wr,
964 send->s_rdma_wr.wr.num_sge,
965 send->s_rdma_wr.wr.next);
966
967 prev = send;
968 if (++send == &ic->i_sends[ic->i_send_ring.w_nr])
969 send = ic->i_sends;
970 }
971
972 /* give a reference to the last op */
973 if (scat == &op->op_sg[op->op_count]) {
974 prev->s_op = op;
975 rds_message_addref(container_of(op, struct rds_message, rdma));
976 }
977
978 if (i < work_alloc) {
979 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i);
980 work_alloc = i;
981 }
982
983 if (nr_sig)
984 atomic_add(nr_sig, &ic->i_signaled_sends);
985
986 failed_wr = &first->s_rdma_wr.wr;
987 ret = ib_post_send(ic->i_cm_id->qp, &first->s_rdma_wr.wr, &failed_wr);
988 rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic,
989 first, &first->s_rdma_wr.wr, ret, failed_wr);
990 BUG_ON(failed_wr != &first->s_rdma_wr.wr);
991 if (ret) {
992 printk(KERN_WARNING "RDS/IB: rdma ib_post_send to %pI6c "
993 "returned %d\n", &conn->c_faddr, ret);
994 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
995 rds_ib_sub_signaled(ic, nr_sig);
996 goto out;
997 }
998
999 if (unlikely(failed_wr != &first->s_rdma_wr.wr)) {
1000 printk(KERN_WARNING "RDS/IB: ib_post_send() rc=%d, but failed_wqe updated!\n", ret);
1001 BUG_ON(failed_wr != &first->s_rdma_wr.wr);
1002 }
1003
1004
1005out:
1006 return ret;
1007}
1008
1009void rds_ib_xmit_path_complete(struct rds_conn_path *cp)
1010{
1011 struct rds_connection *conn = cp->cp_conn;
1012 struct rds_ib_connection *ic = conn->c_transport_data;
1013
1014 /* We may have a pending ACK or window update we were unable
1015 * to send previously (due to flow control). Try again. */
1016 rds_ib_attempt_ack(ic);
1017}