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1/*
2 * Copyright (c) 2006 Oracle. 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/slab.h>
35#include <linux/pci.h>
36#include <linux/dma-mapping.h>
37#include <rdma/rdma_cm.h>
38
39#include "rds.h"
40#include "ib.h"
41
42static struct kmem_cache *rds_ib_incoming_slab;
43static struct kmem_cache *rds_ib_frag_slab;
44static atomic_t rds_ib_allocation = ATOMIC_INIT(0);
45
46void rds_ib_recv_init_ring(struct rds_ib_connection *ic)
47{
48 struct rds_ib_recv_work *recv;
49 u32 i;
50
51 for (i = 0, recv = ic->i_recvs; i < ic->i_recv_ring.w_nr; i++, recv++) {
52 struct ib_sge *sge;
53
54 recv->r_ibinc = NULL;
55 recv->r_frag = NULL;
56
57 recv->r_wr.next = NULL;
58 recv->r_wr.wr_id = i;
59 recv->r_wr.sg_list = recv->r_sge;
60 recv->r_wr.num_sge = RDS_IB_RECV_SGE;
61
62 sge = &recv->r_sge[0];
63 sge->addr = ic->i_recv_hdrs_dma + (i * sizeof(struct rds_header));
64 sge->length = sizeof(struct rds_header);
65 sge->lkey = ic->i_mr->lkey;
66
67 sge = &recv->r_sge[1];
68 sge->addr = 0;
69 sge->length = RDS_FRAG_SIZE;
70 sge->lkey = ic->i_mr->lkey;
71 }
72}
73
74/*
75 * The entire 'from' list, including the from element itself, is put on
76 * to the tail of the 'to' list.
77 */
78static void list_splice_entire_tail(struct list_head *from,
79 struct list_head *to)
80{
81 struct list_head *from_last = from->prev;
82
83 list_splice_tail(from_last, to);
84 list_add_tail(from_last, to);
85}
86
87static void rds_ib_cache_xfer_to_ready(struct rds_ib_refill_cache *cache)
88{
89 struct list_head *tmp;
90
91 tmp = xchg(&cache->xfer, NULL);
92 if (tmp) {
93 if (cache->ready)
94 list_splice_entire_tail(tmp, cache->ready);
95 else
96 cache->ready = tmp;
97 }
98}
99
100static int rds_ib_recv_alloc_cache(struct rds_ib_refill_cache *cache)
101{
102 struct rds_ib_cache_head *head;
103 int cpu;
104
105 cache->percpu = alloc_percpu(struct rds_ib_cache_head);
106 if (!cache->percpu)
107 return -ENOMEM;
108
109 for_each_possible_cpu(cpu) {
110 head = per_cpu_ptr(cache->percpu, cpu);
111 head->first = NULL;
112 head->count = 0;
113 }
114 cache->xfer = NULL;
115 cache->ready = NULL;
116
117 return 0;
118}
119
120int rds_ib_recv_alloc_caches(struct rds_ib_connection *ic)
121{
122 int ret;
123
124 ret = rds_ib_recv_alloc_cache(&ic->i_cache_incs);
125 if (!ret) {
126 ret = rds_ib_recv_alloc_cache(&ic->i_cache_frags);
127 if (ret)
128 free_percpu(ic->i_cache_incs.percpu);
129 }
130
131 return ret;
132}
133
134static void rds_ib_cache_splice_all_lists(struct rds_ib_refill_cache *cache,
135 struct list_head *caller_list)
136{
137 struct rds_ib_cache_head *head;
138 int cpu;
139
140 for_each_possible_cpu(cpu) {
141 head = per_cpu_ptr(cache->percpu, cpu);
142 if (head->first) {
143 list_splice_entire_tail(head->first, caller_list);
144 head->first = NULL;
145 }
146 }
147
148 if (cache->ready) {
149 list_splice_entire_tail(cache->ready, caller_list);
150 cache->ready = NULL;
151 }
152}
153
154void rds_ib_recv_free_caches(struct rds_ib_connection *ic)
155{
156 struct rds_ib_incoming *inc;
157 struct rds_ib_incoming *inc_tmp;
158 struct rds_page_frag *frag;
159 struct rds_page_frag *frag_tmp;
160 LIST_HEAD(list);
161
162 rds_ib_cache_xfer_to_ready(&ic->i_cache_incs);
163 rds_ib_cache_splice_all_lists(&ic->i_cache_incs, &list);
164 free_percpu(ic->i_cache_incs.percpu);
165
166 list_for_each_entry_safe(inc, inc_tmp, &list, ii_cache_entry) {
167 list_del(&inc->ii_cache_entry);
168 WARN_ON(!list_empty(&inc->ii_frags));
169 kmem_cache_free(rds_ib_incoming_slab, inc);
170 }
171
172 rds_ib_cache_xfer_to_ready(&ic->i_cache_frags);
173 rds_ib_cache_splice_all_lists(&ic->i_cache_frags, &list);
174 free_percpu(ic->i_cache_frags.percpu);
175
176 list_for_each_entry_safe(frag, frag_tmp, &list, f_cache_entry) {
177 list_del(&frag->f_cache_entry);
178 WARN_ON(!list_empty(&frag->f_item));
179 kmem_cache_free(rds_ib_frag_slab, frag);
180 }
181}
182
183/* fwd decl */
184static void rds_ib_recv_cache_put(struct list_head *new_item,
185 struct rds_ib_refill_cache *cache);
186static struct list_head *rds_ib_recv_cache_get(struct rds_ib_refill_cache *cache);
187
188
189/* Recycle frag and attached recv buffer f_sg */
190static void rds_ib_frag_free(struct rds_ib_connection *ic,
191 struct rds_page_frag *frag)
192{
193 rdsdebug("frag %p page %p\n", frag, sg_page(&frag->f_sg));
194
195 rds_ib_recv_cache_put(&frag->f_cache_entry, &ic->i_cache_frags);
196}
197
198/* Recycle inc after freeing attached frags */
199void rds_ib_inc_free(struct rds_incoming *inc)
200{
201 struct rds_ib_incoming *ibinc;
202 struct rds_page_frag *frag;
203 struct rds_page_frag *pos;
204 struct rds_ib_connection *ic = inc->i_conn->c_transport_data;
205
206 ibinc = container_of(inc, struct rds_ib_incoming, ii_inc);
207
208 /* Free attached frags */
209 list_for_each_entry_safe(frag, pos, &ibinc->ii_frags, f_item) {
210 list_del_init(&frag->f_item);
211 rds_ib_frag_free(ic, frag);
212 }
213 BUG_ON(!list_empty(&ibinc->ii_frags));
214
215 rdsdebug("freeing ibinc %p inc %p\n", ibinc, inc);
216 rds_ib_recv_cache_put(&ibinc->ii_cache_entry, &ic->i_cache_incs);
217}
218
219static void rds_ib_recv_clear_one(struct rds_ib_connection *ic,
220 struct rds_ib_recv_work *recv)
221{
222 if (recv->r_ibinc) {
223 rds_inc_put(&recv->r_ibinc->ii_inc);
224 recv->r_ibinc = NULL;
225 }
226 if (recv->r_frag) {
227 ib_dma_unmap_sg(ic->i_cm_id->device, &recv->r_frag->f_sg, 1, DMA_FROM_DEVICE);
228 rds_ib_frag_free(ic, recv->r_frag);
229 recv->r_frag = NULL;
230 }
231}
232
233void rds_ib_recv_clear_ring(struct rds_ib_connection *ic)
234{
235 u32 i;
236
237 for (i = 0; i < ic->i_recv_ring.w_nr; i++)
238 rds_ib_recv_clear_one(ic, &ic->i_recvs[i]);
239}
240
241static struct rds_ib_incoming *rds_ib_refill_one_inc(struct rds_ib_connection *ic,
242 gfp_t slab_mask)
243{
244 struct rds_ib_incoming *ibinc;
245 struct list_head *cache_item;
246 int avail_allocs;
247
248 cache_item = rds_ib_recv_cache_get(&ic->i_cache_incs);
249 if (cache_item) {
250 ibinc = container_of(cache_item, struct rds_ib_incoming, ii_cache_entry);
251 } else {
252 avail_allocs = atomic_add_unless(&rds_ib_allocation,
253 1, rds_ib_sysctl_max_recv_allocation);
254 if (!avail_allocs) {
255 rds_ib_stats_inc(s_ib_rx_alloc_limit);
256 return NULL;
257 }
258 ibinc = kmem_cache_alloc(rds_ib_incoming_slab, slab_mask);
259 if (!ibinc) {
260 atomic_dec(&rds_ib_allocation);
261 return NULL;
262 }
263 }
264 INIT_LIST_HEAD(&ibinc->ii_frags);
265 rds_inc_init(&ibinc->ii_inc, ic->conn, ic->conn->c_faddr);
266
267 return ibinc;
268}
269
270static struct rds_page_frag *rds_ib_refill_one_frag(struct rds_ib_connection *ic,
271 gfp_t slab_mask, gfp_t page_mask)
272{
273 struct rds_page_frag *frag;
274 struct list_head *cache_item;
275 int ret;
276
277 cache_item = rds_ib_recv_cache_get(&ic->i_cache_frags);
278 if (cache_item) {
279 frag = container_of(cache_item, struct rds_page_frag, f_cache_entry);
280 } else {
281 frag = kmem_cache_alloc(rds_ib_frag_slab, slab_mask);
282 if (!frag)
283 return NULL;
284
285 sg_init_table(&frag->f_sg, 1);
286 ret = rds_page_remainder_alloc(&frag->f_sg,
287 RDS_FRAG_SIZE, page_mask);
288 if (ret) {
289 kmem_cache_free(rds_ib_frag_slab, frag);
290 return NULL;
291 }
292 }
293
294 INIT_LIST_HEAD(&frag->f_item);
295
296 return frag;
297}
298
299static int rds_ib_recv_refill_one(struct rds_connection *conn,
300 struct rds_ib_recv_work *recv, int prefill)
301{
302 struct rds_ib_connection *ic = conn->c_transport_data;
303 struct ib_sge *sge;
304 int ret = -ENOMEM;
305 gfp_t slab_mask = GFP_NOWAIT;
306 gfp_t page_mask = GFP_NOWAIT;
307
308 if (prefill) {
309 slab_mask = GFP_KERNEL;
310 page_mask = GFP_HIGHUSER;
311 }
312
313 if (!ic->i_cache_incs.ready)
314 rds_ib_cache_xfer_to_ready(&ic->i_cache_incs);
315 if (!ic->i_cache_frags.ready)
316 rds_ib_cache_xfer_to_ready(&ic->i_cache_frags);
317
318 /*
319 * ibinc was taken from recv if recv contained the start of a message.
320 * recvs that were continuations will still have this allocated.
321 */
322 if (!recv->r_ibinc) {
323 recv->r_ibinc = rds_ib_refill_one_inc(ic, slab_mask);
324 if (!recv->r_ibinc)
325 goto out;
326 }
327
328 WARN_ON(recv->r_frag); /* leak! */
329 recv->r_frag = rds_ib_refill_one_frag(ic, slab_mask, page_mask);
330 if (!recv->r_frag)
331 goto out;
332
333 ret = ib_dma_map_sg(ic->i_cm_id->device, &recv->r_frag->f_sg,
334 1, DMA_FROM_DEVICE);
335 WARN_ON(ret != 1);
336
337 sge = &recv->r_sge[0];
338 sge->addr = ic->i_recv_hdrs_dma + (recv - ic->i_recvs) * sizeof(struct rds_header);
339 sge->length = sizeof(struct rds_header);
340
341 sge = &recv->r_sge[1];
342 sge->addr = sg_dma_address(&recv->r_frag->f_sg);
343 sge->length = sg_dma_len(&recv->r_frag->f_sg);
344
345 ret = 0;
346out:
347 return ret;
348}
349
350/*
351 * This tries to allocate and post unused work requests after making sure that
352 * they have all the allocations they need to queue received fragments into
353 * sockets.
354 *
355 * -1 is returned if posting fails due to temporary resource exhaustion.
356 */
357void rds_ib_recv_refill(struct rds_connection *conn, int prefill)
358{
359 struct rds_ib_connection *ic = conn->c_transport_data;
360 struct rds_ib_recv_work *recv;
361 struct ib_recv_wr *failed_wr;
362 unsigned int posted = 0;
363 int ret = 0;
364 u32 pos;
365
366 while ((prefill || rds_conn_up(conn)) &&
367 rds_ib_ring_alloc(&ic->i_recv_ring, 1, &pos)) {
368 if (pos >= ic->i_recv_ring.w_nr) {
369 printk(KERN_NOTICE "Argh - ring alloc returned pos=%u\n",
370 pos);
371 break;
372 }
373
374 recv = &ic->i_recvs[pos];
375 ret = rds_ib_recv_refill_one(conn, recv, prefill);
376 if (ret) {
377 break;
378 }
379
380 /* XXX when can this fail? */
381 ret = ib_post_recv(ic->i_cm_id->qp, &recv->r_wr, &failed_wr);
382 rdsdebug("recv %p ibinc %p page %p addr %lu ret %d\n", recv,
383 recv->r_ibinc, sg_page(&recv->r_frag->f_sg),
384 (long) sg_dma_address(&recv->r_frag->f_sg), ret);
385 if (ret) {
386 rds_ib_conn_error(conn, "recv post on "
387 "%pI4 returned %d, disconnecting and "
388 "reconnecting\n", &conn->c_faddr,
389 ret);
390 break;
391 }
392
393 posted++;
394 }
395
396 /* We're doing flow control - update the window. */
397 if (ic->i_flowctl && posted)
398 rds_ib_advertise_credits(conn, posted);
399
400 if (ret)
401 rds_ib_ring_unalloc(&ic->i_recv_ring, 1);
402}
403
404/*
405 * We want to recycle several types of recv allocations, like incs and frags.
406 * To use this, the *_free() function passes in the ptr to a list_head within
407 * the recyclee, as well as the cache to put it on.
408 *
409 * First, we put the memory on a percpu list. When this reaches a certain size,
410 * We move it to an intermediate non-percpu list in a lockless manner, with some
411 * xchg/compxchg wizardry.
412 *
413 * N.B. Instead of a list_head as the anchor, we use a single pointer, which can
414 * be NULL and xchg'd. The list is actually empty when the pointer is NULL, and
415 * list_empty() will return true with one element is actually present.
416 */
417static void rds_ib_recv_cache_put(struct list_head *new_item,
418 struct rds_ib_refill_cache *cache)
419{
420 unsigned long flags;
421 struct rds_ib_cache_head *chp;
422 struct list_head *old;
423
424 local_irq_save(flags);
425
426 chp = per_cpu_ptr(cache->percpu, smp_processor_id());
427 if (!chp->first)
428 INIT_LIST_HEAD(new_item);
429 else /* put on front */
430 list_add_tail(new_item, chp->first);
431 chp->first = new_item;
432 chp->count++;
433
434 if (chp->count < RDS_IB_RECYCLE_BATCH_COUNT)
435 goto end;
436
437 /*
438 * Return our per-cpu first list to the cache's xfer by atomically
439 * grabbing the current xfer list, appending it to our per-cpu list,
440 * and then atomically returning that entire list back to the
441 * cache's xfer list as long as it's still empty.
442 */
443 do {
444 old = xchg(&cache->xfer, NULL);
445 if (old)
446 list_splice_entire_tail(old, chp->first);
447 old = cmpxchg(&cache->xfer, NULL, chp->first);
448 } while (old);
449
450 chp->first = NULL;
451 chp->count = 0;
452end:
453 local_irq_restore(flags);
454}
455
456static struct list_head *rds_ib_recv_cache_get(struct rds_ib_refill_cache *cache)
457{
458 struct list_head *head = cache->ready;
459
460 if (head) {
461 if (!list_empty(head)) {
462 cache->ready = head->next;
463 list_del_init(head);
464 } else
465 cache->ready = NULL;
466 }
467
468 return head;
469}
470
471int rds_ib_inc_copy_to_user(struct rds_incoming *inc, struct iovec *first_iov,
472 size_t size)
473{
474 struct rds_ib_incoming *ibinc;
475 struct rds_page_frag *frag;
476 struct iovec *iov = first_iov;
477 unsigned long to_copy;
478 unsigned long frag_off = 0;
479 unsigned long iov_off = 0;
480 int copied = 0;
481 int ret;
482 u32 len;
483
484 ibinc = container_of(inc, struct rds_ib_incoming, ii_inc);
485 frag = list_entry(ibinc->ii_frags.next, struct rds_page_frag, f_item);
486 len = be32_to_cpu(inc->i_hdr.h_len);
487
488 while (copied < size && copied < len) {
489 if (frag_off == RDS_FRAG_SIZE) {
490 frag = list_entry(frag->f_item.next,
491 struct rds_page_frag, f_item);
492 frag_off = 0;
493 }
494 while (iov_off == iov->iov_len) {
495 iov_off = 0;
496 iov++;
497 }
498
499 to_copy = min(iov->iov_len - iov_off, RDS_FRAG_SIZE - frag_off);
500 to_copy = min_t(size_t, to_copy, size - copied);
501 to_copy = min_t(unsigned long, to_copy, len - copied);
502
503 rdsdebug("%lu bytes to user [%p, %zu] + %lu from frag "
504 "[%p, %u] + %lu\n",
505 to_copy, iov->iov_base, iov->iov_len, iov_off,
506 sg_page(&frag->f_sg), frag->f_sg.offset, frag_off);
507
508 /* XXX needs + offset for multiple recvs per page */
509 ret = rds_page_copy_to_user(sg_page(&frag->f_sg),
510 frag->f_sg.offset + frag_off,
511 iov->iov_base + iov_off,
512 to_copy);
513 if (ret) {
514 copied = ret;
515 break;
516 }
517
518 iov_off += to_copy;
519 frag_off += to_copy;
520 copied += to_copy;
521 }
522
523 return copied;
524}
525
526/* ic starts out kzalloc()ed */
527void rds_ib_recv_init_ack(struct rds_ib_connection *ic)
528{
529 struct ib_send_wr *wr = &ic->i_ack_wr;
530 struct ib_sge *sge = &ic->i_ack_sge;
531
532 sge->addr = ic->i_ack_dma;
533 sge->length = sizeof(struct rds_header);
534 sge->lkey = ic->i_mr->lkey;
535
536 wr->sg_list = sge;
537 wr->num_sge = 1;
538 wr->opcode = IB_WR_SEND;
539 wr->wr_id = RDS_IB_ACK_WR_ID;
540 wr->send_flags = IB_SEND_SIGNALED | IB_SEND_SOLICITED;
541}
542
543/*
544 * You'd think that with reliable IB connections you wouldn't need to ack
545 * messages that have been received. The problem is that IB hardware generates
546 * an ack message before it has DMAed the message into memory. This creates a
547 * potential message loss if the HCA is disabled for any reason between when it
548 * sends the ack and before the message is DMAed and processed. This is only a
549 * potential issue if another HCA is available for fail-over.
550 *
551 * When the remote host receives our ack they'll free the sent message from
552 * their send queue. To decrease the latency of this we always send an ack
553 * immediately after we've received messages.
554 *
555 * For simplicity, we only have one ack in flight at a time. This puts
556 * pressure on senders to have deep enough send queues to absorb the latency of
557 * a single ack frame being in flight. This might not be good enough.
558 *
559 * This is implemented by have a long-lived send_wr and sge which point to a
560 * statically allocated ack frame. This ack wr does not fall under the ring
561 * accounting that the tx and rx wrs do. The QP attribute specifically makes
562 * room for it beyond the ring size. Send completion notices its special
563 * wr_id and avoids working with the ring in that case.
564 */
565#ifndef KERNEL_HAS_ATOMIC64
566static void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq,
567 int ack_required)
568{
569 unsigned long flags;
570
571 spin_lock_irqsave(&ic->i_ack_lock, flags);
572 ic->i_ack_next = seq;
573 if (ack_required)
574 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
575 spin_unlock_irqrestore(&ic->i_ack_lock, flags);
576}
577
578static u64 rds_ib_get_ack(struct rds_ib_connection *ic)
579{
580 unsigned long flags;
581 u64 seq;
582
583 clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
584
585 spin_lock_irqsave(&ic->i_ack_lock, flags);
586 seq = ic->i_ack_next;
587 spin_unlock_irqrestore(&ic->i_ack_lock, flags);
588
589 return seq;
590}
591#else
592static void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq,
593 int ack_required)
594{
595 atomic64_set(&ic->i_ack_next, seq);
596 if (ack_required) {
597 smp_mb__before_clear_bit();
598 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
599 }
600}
601
602static u64 rds_ib_get_ack(struct rds_ib_connection *ic)
603{
604 clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
605 smp_mb__after_clear_bit();
606
607 return atomic64_read(&ic->i_ack_next);
608}
609#endif
610
611
612static void rds_ib_send_ack(struct rds_ib_connection *ic, unsigned int adv_credits)
613{
614 struct rds_header *hdr = ic->i_ack;
615 struct ib_send_wr *failed_wr;
616 u64 seq;
617 int ret;
618
619 seq = rds_ib_get_ack(ic);
620
621 rdsdebug("send_ack: ic %p ack %llu\n", ic, (unsigned long long) seq);
622 rds_message_populate_header(hdr, 0, 0, 0);
623 hdr->h_ack = cpu_to_be64(seq);
624 hdr->h_credit = adv_credits;
625 rds_message_make_checksum(hdr);
626 ic->i_ack_queued = jiffies;
627
628 ret = ib_post_send(ic->i_cm_id->qp, &ic->i_ack_wr, &failed_wr);
629 if (unlikely(ret)) {
630 /* Failed to send. Release the WR, and
631 * force another ACK.
632 */
633 clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
634 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
635
636 rds_ib_stats_inc(s_ib_ack_send_failure);
637
638 rds_ib_conn_error(ic->conn, "sending ack failed\n");
639 } else
640 rds_ib_stats_inc(s_ib_ack_sent);
641}
642
643/*
644 * There are 3 ways of getting acknowledgements to the peer:
645 * 1. We call rds_ib_attempt_ack from the recv completion handler
646 * to send an ACK-only frame.
647 * However, there can be only one such frame in the send queue
648 * at any time, so we may have to postpone it.
649 * 2. When another (data) packet is transmitted while there's
650 * an ACK in the queue, we piggyback the ACK sequence number
651 * on the data packet.
652 * 3. If the ACK WR is done sending, we get called from the
653 * send queue completion handler, and check whether there's
654 * another ACK pending (postponed because the WR was on the
655 * queue). If so, we transmit it.
656 *
657 * We maintain 2 variables:
658 * - i_ack_flags, which keeps track of whether the ACK WR
659 * is currently in the send queue or not (IB_ACK_IN_FLIGHT)
660 * - i_ack_next, which is the last sequence number we received
661 *
662 * Potentially, send queue and receive queue handlers can run concurrently.
663 * It would be nice to not have to use a spinlock to synchronize things,
664 * but the one problem that rules this out is that 64bit updates are
665 * not atomic on all platforms. Things would be a lot simpler if
666 * we had atomic64 or maybe cmpxchg64 everywhere.
667 *
668 * Reconnecting complicates this picture just slightly. When we
669 * reconnect, we may be seeing duplicate packets. The peer
670 * is retransmitting them, because it hasn't seen an ACK for
671 * them. It is important that we ACK these.
672 *
673 * ACK mitigation adds a header flag "ACK_REQUIRED"; any packet with
674 * this flag set *MUST* be acknowledged immediately.
675 */
676
677/*
678 * When we get here, we're called from the recv queue handler.
679 * Check whether we ought to transmit an ACK.
680 */
681void rds_ib_attempt_ack(struct rds_ib_connection *ic)
682{
683 unsigned int adv_credits;
684
685 if (!test_bit(IB_ACK_REQUESTED, &ic->i_ack_flags))
686 return;
687
688 if (test_and_set_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags)) {
689 rds_ib_stats_inc(s_ib_ack_send_delayed);
690 return;
691 }
692
693 /* Can we get a send credit? */
694 if (!rds_ib_send_grab_credits(ic, 1, &adv_credits, 0, RDS_MAX_ADV_CREDIT)) {
695 rds_ib_stats_inc(s_ib_tx_throttle);
696 clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
697 return;
698 }
699
700 clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
701 rds_ib_send_ack(ic, adv_credits);
702}
703
704/*
705 * We get here from the send completion handler, when the
706 * adapter tells us the ACK frame was sent.
707 */
708void rds_ib_ack_send_complete(struct rds_ib_connection *ic)
709{
710 clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
711 rds_ib_attempt_ack(ic);
712}
713
714/*
715 * This is called by the regular xmit code when it wants to piggyback
716 * an ACK on an outgoing frame.
717 */
718u64 rds_ib_piggyb_ack(struct rds_ib_connection *ic)
719{
720 if (test_and_clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags))
721 rds_ib_stats_inc(s_ib_ack_send_piggybacked);
722 return rds_ib_get_ack(ic);
723}
724
725/*
726 * It's kind of lame that we're copying from the posted receive pages into
727 * long-lived bitmaps. We could have posted the bitmaps and rdma written into
728 * them. But receiving new congestion bitmaps should be a *rare* event, so
729 * hopefully we won't need to invest that complexity in making it more
730 * efficient. By copying we can share a simpler core with TCP which has to
731 * copy.
732 */
733static void rds_ib_cong_recv(struct rds_connection *conn,
734 struct rds_ib_incoming *ibinc)
735{
736 struct rds_cong_map *map;
737 unsigned int map_off;
738 unsigned int map_page;
739 struct rds_page_frag *frag;
740 unsigned long frag_off;
741 unsigned long to_copy;
742 unsigned long copied;
743 uint64_t uncongested = 0;
744 void *addr;
745
746 /* catch completely corrupt packets */
747 if (be32_to_cpu(ibinc->ii_inc.i_hdr.h_len) != RDS_CONG_MAP_BYTES)
748 return;
749
750 map = conn->c_fcong;
751 map_page = 0;
752 map_off = 0;
753
754 frag = list_entry(ibinc->ii_frags.next, struct rds_page_frag, f_item);
755 frag_off = 0;
756
757 copied = 0;
758
759 while (copied < RDS_CONG_MAP_BYTES) {
760 uint64_t *src, *dst;
761 unsigned int k;
762
763 to_copy = min(RDS_FRAG_SIZE - frag_off, PAGE_SIZE - map_off);
764 BUG_ON(to_copy & 7); /* Must be 64bit aligned. */
765
766 addr = kmap_atomic(sg_page(&frag->f_sg));
767
768 src = addr + frag_off;
769 dst = (void *)map->m_page_addrs[map_page] + map_off;
770 for (k = 0; k < to_copy; k += 8) {
771 /* Record ports that became uncongested, ie
772 * bits that changed from 0 to 1. */
773 uncongested |= ~(*src) & *dst;
774 *dst++ = *src++;
775 }
776 kunmap_atomic(addr);
777
778 copied += to_copy;
779
780 map_off += to_copy;
781 if (map_off == PAGE_SIZE) {
782 map_off = 0;
783 map_page++;
784 }
785
786 frag_off += to_copy;
787 if (frag_off == RDS_FRAG_SIZE) {
788 frag = list_entry(frag->f_item.next,
789 struct rds_page_frag, f_item);
790 frag_off = 0;
791 }
792 }
793
794 /* the congestion map is in little endian order */
795 uncongested = le64_to_cpu(uncongested);
796
797 rds_cong_map_updated(map, uncongested);
798}
799
800/*
801 * Rings are posted with all the allocations they'll need to queue the
802 * incoming message to the receiving socket so this can't fail.
803 * All fragments start with a header, so we can make sure we're not receiving
804 * garbage, and we can tell a small 8 byte fragment from an ACK frame.
805 */
806struct rds_ib_ack_state {
807 u64 ack_next;
808 u64 ack_recv;
809 unsigned int ack_required:1;
810 unsigned int ack_next_valid:1;
811 unsigned int ack_recv_valid:1;
812};
813
814static void rds_ib_process_recv(struct rds_connection *conn,
815 struct rds_ib_recv_work *recv, u32 data_len,
816 struct rds_ib_ack_state *state)
817{
818 struct rds_ib_connection *ic = conn->c_transport_data;
819 struct rds_ib_incoming *ibinc = ic->i_ibinc;
820 struct rds_header *ihdr, *hdr;
821
822 /* XXX shut down the connection if port 0,0 are seen? */
823
824 rdsdebug("ic %p ibinc %p recv %p byte len %u\n", ic, ibinc, recv,
825 data_len);
826
827 if (data_len < sizeof(struct rds_header)) {
828 rds_ib_conn_error(conn, "incoming message "
829 "from %pI4 didn't include a "
830 "header, disconnecting and "
831 "reconnecting\n",
832 &conn->c_faddr);
833 return;
834 }
835 data_len -= sizeof(struct rds_header);
836
837 ihdr = &ic->i_recv_hdrs[recv - ic->i_recvs];
838
839 /* Validate the checksum. */
840 if (!rds_message_verify_checksum(ihdr)) {
841 rds_ib_conn_error(conn, "incoming message "
842 "from %pI4 has corrupted header - "
843 "forcing a reconnect\n",
844 &conn->c_faddr);
845 rds_stats_inc(s_recv_drop_bad_checksum);
846 return;
847 }
848
849 /* Process the ACK sequence which comes with every packet */
850 state->ack_recv = be64_to_cpu(ihdr->h_ack);
851 state->ack_recv_valid = 1;
852
853 /* Process the credits update if there was one */
854 if (ihdr->h_credit)
855 rds_ib_send_add_credits(conn, ihdr->h_credit);
856
857 if (ihdr->h_sport == 0 && ihdr->h_dport == 0 && data_len == 0) {
858 /* This is an ACK-only packet. The fact that it gets
859 * special treatment here is that historically, ACKs
860 * were rather special beasts.
861 */
862 rds_ib_stats_inc(s_ib_ack_received);
863
864 /*
865 * Usually the frags make their way on to incs and are then freed as
866 * the inc is freed. We don't go that route, so we have to drop the
867 * page ref ourselves. We can't just leave the page on the recv
868 * because that confuses the dma mapping of pages and each recv's use
869 * of a partial page.
870 *
871 * FIXME: Fold this into the code path below.
872 */
873 rds_ib_frag_free(ic, recv->r_frag);
874 recv->r_frag = NULL;
875 return;
876 }
877
878 /*
879 * If we don't already have an inc on the connection then this
880 * fragment has a header and starts a message.. copy its header
881 * into the inc and save the inc so we can hang upcoming fragments
882 * off its list.
883 */
884 if (!ibinc) {
885 ibinc = recv->r_ibinc;
886 recv->r_ibinc = NULL;
887 ic->i_ibinc = ibinc;
888
889 hdr = &ibinc->ii_inc.i_hdr;
890 memcpy(hdr, ihdr, sizeof(*hdr));
891 ic->i_recv_data_rem = be32_to_cpu(hdr->h_len);
892
893 rdsdebug("ic %p ibinc %p rem %u flag 0x%x\n", ic, ibinc,
894 ic->i_recv_data_rem, hdr->h_flags);
895 } else {
896 hdr = &ibinc->ii_inc.i_hdr;
897 /* We can't just use memcmp here; fragments of a
898 * single message may carry different ACKs */
899 if (hdr->h_sequence != ihdr->h_sequence ||
900 hdr->h_len != ihdr->h_len ||
901 hdr->h_sport != ihdr->h_sport ||
902 hdr->h_dport != ihdr->h_dport) {
903 rds_ib_conn_error(conn,
904 "fragment header mismatch; forcing reconnect\n");
905 return;
906 }
907 }
908
909 list_add_tail(&recv->r_frag->f_item, &ibinc->ii_frags);
910 recv->r_frag = NULL;
911
912 if (ic->i_recv_data_rem > RDS_FRAG_SIZE)
913 ic->i_recv_data_rem -= RDS_FRAG_SIZE;
914 else {
915 ic->i_recv_data_rem = 0;
916 ic->i_ibinc = NULL;
917
918 if (ibinc->ii_inc.i_hdr.h_flags == RDS_FLAG_CONG_BITMAP)
919 rds_ib_cong_recv(conn, ibinc);
920 else {
921 rds_recv_incoming(conn, conn->c_faddr, conn->c_laddr,
922 &ibinc->ii_inc, GFP_ATOMIC);
923 state->ack_next = be64_to_cpu(hdr->h_sequence);
924 state->ack_next_valid = 1;
925 }
926
927 /* Evaluate the ACK_REQUIRED flag *after* we received
928 * the complete frame, and after bumping the next_rx
929 * sequence. */
930 if (hdr->h_flags & RDS_FLAG_ACK_REQUIRED) {
931 rds_stats_inc(s_recv_ack_required);
932 state->ack_required = 1;
933 }
934
935 rds_inc_put(&ibinc->ii_inc);
936 }
937}
938
939/*
940 * Plucking the oldest entry from the ring can be done concurrently with
941 * the thread refilling the ring. Each ring operation is protected by
942 * spinlocks and the transient state of refilling doesn't change the
943 * recording of which entry is oldest.
944 *
945 * This relies on IB only calling one cq comp_handler for each cq so that
946 * there will only be one caller of rds_recv_incoming() per RDS connection.
947 */
948void rds_ib_recv_cq_comp_handler(struct ib_cq *cq, void *context)
949{
950 struct rds_connection *conn = context;
951 struct rds_ib_connection *ic = conn->c_transport_data;
952
953 rdsdebug("conn %p cq %p\n", conn, cq);
954
955 rds_ib_stats_inc(s_ib_rx_cq_call);
956
957 tasklet_schedule(&ic->i_recv_tasklet);
958}
959
960static inline void rds_poll_cq(struct rds_ib_connection *ic,
961 struct rds_ib_ack_state *state)
962{
963 struct rds_connection *conn = ic->conn;
964 struct ib_wc wc;
965 struct rds_ib_recv_work *recv;
966
967 while (ib_poll_cq(ic->i_recv_cq, 1, &wc) > 0) {
968 rdsdebug("wc wr_id 0x%llx status %u (%s) byte_len %u imm_data %u\n",
969 (unsigned long long)wc.wr_id, wc.status,
970 rds_ib_wc_status_str(wc.status), wc.byte_len,
971 be32_to_cpu(wc.ex.imm_data));
972 rds_ib_stats_inc(s_ib_rx_cq_event);
973
974 recv = &ic->i_recvs[rds_ib_ring_oldest(&ic->i_recv_ring)];
975
976 ib_dma_unmap_sg(ic->i_cm_id->device, &recv->r_frag->f_sg, 1, DMA_FROM_DEVICE);
977
978 /*
979 * Also process recvs in connecting state because it is possible
980 * to get a recv completion _before_ the rdmacm ESTABLISHED
981 * event is processed.
982 */
983 if (wc.status == IB_WC_SUCCESS) {
984 rds_ib_process_recv(conn, recv, wc.byte_len, state);
985 } else {
986 /* We expect errors as the qp is drained during shutdown */
987 if (rds_conn_up(conn) || rds_conn_connecting(conn))
988 rds_ib_conn_error(conn, "recv completion on %pI4 had "
989 "status %u (%s), disconnecting and "
990 "reconnecting\n", &conn->c_faddr,
991 wc.status,
992 rds_ib_wc_status_str(wc.status));
993 }
994
995 /*
996 * It's very important that we only free this ring entry if we've truly
997 * freed the resources allocated to the entry. The refilling path can
998 * leak if we don't.
999 */
1000 rds_ib_ring_free(&ic->i_recv_ring, 1);
1001 }
1002}
1003
1004void rds_ib_recv_tasklet_fn(unsigned long data)
1005{
1006 struct rds_ib_connection *ic = (struct rds_ib_connection *) data;
1007 struct rds_connection *conn = ic->conn;
1008 struct rds_ib_ack_state state = { 0, };
1009
1010 rds_poll_cq(ic, &state);
1011 ib_req_notify_cq(ic->i_recv_cq, IB_CQ_SOLICITED);
1012 rds_poll_cq(ic, &state);
1013
1014 if (state.ack_next_valid)
1015 rds_ib_set_ack(ic, state.ack_next, state.ack_required);
1016 if (state.ack_recv_valid && state.ack_recv > ic->i_ack_recv) {
1017 rds_send_drop_acked(conn, state.ack_recv, NULL);
1018 ic->i_ack_recv = state.ack_recv;
1019 }
1020 if (rds_conn_up(conn))
1021 rds_ib_attempt_ack(ic);
1022
1023 /* If we ever end up with a really empty receive ring, we're
1024 * in deep trouble, as the sender will definitely see RNR
1025 * timeouts. */
1026 if (rds_ib_ring_empty(&ic->i_recv_ring))
1027 rds_ib_stats_inc(s_ib_rx_ring_empty);
1028
1029 if (rds_ib_ring_low(&ic->i_recv_ring))
1030 rds_ib_recv_refill(conn, 0);
1031}
1032
1033int rds_ib_recv(struct rds_connection *conn)
1034{
1035 struct rds_ib_connection *ic = conn->c_transport_data;
1036 int ret = 0;
1037
1038 rdsdebug("conn %p\n", conn);
1039 if (rds_conn_up(conn))
1040 rds_ib_attempt_ack(ic);
1041
1042 return ret;
1043}
1044
1045int rds_ib_recv_init(void)
1046{
1047 struct sysinfo si;
1048 int ret = -ENOMEM;
1049
1050 /* Default to 30% of all available RAM for recv memory */
1051 si_meminfo(&si);
1052 rds_ib_sysctl_max_recv_allocation = si.totalram / 3 * PAGE_SIZE / RDS_FRAG_SIZE;
1053
1054 rds_ib_incoming_slab = kmem_cache_create("rds_ib_incoming",
1055 sizeof(struct rds_ib_incoming),
1056 0, SLAB_HWCACHE_ALIGN, NULL);
1057 if (!rds_ib_incoming_slab)
1058 goto out;
1059
1060 rds_ib_frag_slab = kmem_cache_create("rds_ib_frag",
1061 sizeof(struct rds_page_frag),
1062 0, SLAB_HWCACHE_ALIGN, NULL);
1063 if (!rds_ib_frag_slab)
1064 kmem_cache_destroy(rds_ib_incoming_slab);
1065 else
1066 ret = 0;
1067out:
1068 return ret;
1069}
1070
1071void rds_ib_recv_exit(void)
1072{
1073 kmem_cache_destroy(rds_ib_incoming_slab);
1074 kmem_cache_destroy(rds_ib_frag_slab);
1075}
1/*
2 * Copyright (c) 2006 Oracle. 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/slab.h>
35#include <linux/pci.h>
36#include <linux/dma-mapping.h>
37#include <rdma/rdma_cm.h>
38
39#include "rds_single_path.h"
40#include "rds.h"
41#include "ib.h"
42
43static struct kmem_cache *rds_ib_incoming_slab;
44static struct kmem_cache *rds_ib_frag_slab;
45static atomic_t rds_ib_allocation = ATOMIC_INIT(0);
46
47void rds_ib_recv_init_ring(struct rds_ib_connection *ic)
48{
49 struct rds_ib_recv_work *recv;
50 u32 i;
51
52 for (i = 0, recv = ic->i_recvs; i < ic->i_recv_ring.w_nr; i++, recv++) {
53 struct ib_sge *sge;
54
55 recv->r_ibinc = NULL;
56 recv->r_frag = NULL;
57
58 recv->r_wr.next = NULL;
59 recv->r_wr.wr_id = i;
60 recv->r_wr.sg_list = recv->r_sge;
61 recv->r_wr.num_sge = RDS_IB_RECV_SGE;
62
63 sge = &recv->r_sge[0];
64 sge->addr = ic->i_recv_hdrs_dma + (i * sizeof(struct rds_header));
65 sge->length = sizeof(struct rds_header);
66 sge->lkey = ic->i_pd->local_dma_lkey;
67
68 sge = &recv->r_sge[1];
69 sge->addr = 0;
70 sge->length = RDS_FRAG_SIZE;
71 sge->lkey = ic->i_pd->local_dma_lkey;
72 }
73}
74
75/*
76 * The entire 'from' list, including the from element itself, is put on
77 * to the tail of the 'to' list.
78 */
79static void list_splice_entire_tail(struct list_head *from,
80 struct list_head *to)
81{
82 struct list_head *from_last = from->prev;
83
84 list_splice_tail(from_last, to);
85 list_add_tail(from_last, to);
86}
87
88static void rds_ib_cache_xfer_to_ready(struct rds_ib_refill_cache *cache)
89{
90 struct list_head *tmp;
91
92 tmp = xchg(&cache->xfer, NULL);
93 if (tmp) {
94 if (cache->ready)
95 list_splice_entire_tail(tmp, cache->ready);
96 else
97 cache->ready = tmp;
98 }
99}
100
101static int rds_ib_recv_alloc_cache(struct rds_ib_refill_cache *cache)
102{
103 struct rds_ib_cache_head *head;
104 int cpu;
105
106 cache->percpu = alloc_percpu(struct rds_ib_cache_head);
107 if (!cache->percpu)
108 return -ENOMEM;
109
110 for_each_possible_cpu(cpu) {
111 head = per_cpu_ptr(cache->percpu, cpu);
112 head->first = NULL;
113 head->count = 0;
114 }
115 cache->xfer = NULL;
116 cache->ready = NULL;
117
118 return 0;
119}
120
121int rds_ib_recv_alloc_caches(struct rds_ib_connection *ic)
122{
123 int ret;
124
125 ret = rds_ib_recv_alloc_cache(&ic->i_cache_incs);
126 if (!ret) {
127 ret = rds_ib_recv_alloc_cache(&ic->i_cache_frags);
128 if (ret)
129 free_percpu(ic->i_cache_incs.percpu);
130 }
131
132 return ret;
133}
134
135static void rds_ib_cache_splice_all_lists(struct rds_ib_refill_cache *cache,
136 struct list_head *caller_list)
137{
138 struct rds_ib_cache_head *head;
139 int cpu;
140
141 for_each_possible_cpu(cpu) {
142 head = per_cpu_ptr(cache->percpu, cpu);
143 if (head->first) {
144 list_splice_entire_tail(head->first, caller_list);
145 head->first = NULL;
146 }
147 }
148
149 if (cache->ready) {
150 list_splice_entire_tail(cache->ready, caller_list);
151 cache->ready = NULL;
152 }
153}
154
155void rds_ib_recv_free_caches(struct rds_ib_connection *ic)
156{
157 struct rds_ib_incoming *inc;
158 struct rds_ib_incoming *inc_tmp;
159 struct rds_page_frag *frag;
160 struct rds_page_frag *frag_tmp;
161 LIST_HEAD(list);
162
163 rds_ib_cache_xfer_to_ready(&ic->i_cache_incs);
164 rds_ib_cache_splice_all_lists(&ic->i_cache_incs, &list);
165 free_percpu(ic->i_cache_incs.percpu);
166
167 list_for_each_entry_safe(inc, inc_tmp, &list, ii_cache_entry) {
168 list_del(&inc->ii_cache_entry);
169 WARN_ON(!list_empty(&inc->ii_frags));
170 kmem_cache_free(rds_ib_incoming_slab, inc);
171 }
172
173 rds_ib_cache_xfer_to_ready(&ic->i_cache_frags);
174 rds_ib_cache_splice_all_lists(&ic->i_cache_frags, &list);
175 free_percpu(ic->i_cache_frags.percpu);
176
177 list_for_each_entry_safe(frag, frag_tmp, &list, f_cache_entry) {
178 list_del(&frag->f_cache_entry);
179 WARN_ON(!list_empty(&frag->f_item));
180 kmem_cache_free(rds_ib_frag_slab, frag);
181 }
182}
183
184/* fwd decl */
185static void rds_ib_recv_cache_put(struct list_head *new_item,
186 struct rds_ib_refill_cache *cache);
187static struct list_head *rds_ib_recv_cache_get(struct rds_ib_refill_cache *cache);
188
189
190/* Recycle frag and attached recv buffer f_sg */
191static void rds_ib_frag_free(struct rds_ib_connection *ic,
192 struct rds_page_frag *frag)
193{
194 rdsdebug("frag %p page %p\n", frag, sg_page(&frag->f_sg));
195
196 rds_ib_recv_cache_put(&frag->f_cache_entry, &ic->i_cache_frags);
197 atomic_add(RDS_FRAG_SIZE / SZ_1K, &ic->i_cache_allocs);
198 rds_ib_stats_add(s_ib_recv_added_to_cache, RDS_FRAG_SIZE);
199}
200
201/* Recycle inc after freeing attached frags */
202void rds_ib_inc_free(struct rds_incoming *inc)
203{
204 struct rds_ib_incoming *ibinc;
205 struct rds_page_frag *frag;
206 struct rds_page_frag *pos;
207 struct rds_ib_connection *ic = inc->i_conn->c_transport_data;
208
209 ibinc = container_of(inc, struct rds_ib_incoming, ii_inc);
210
211 /* Free attached frags */
212 list_for_each_entry_safe(frag, pos, &ibinc->ii_frags, f_item) {
213 list_del_init(&frag->f_item);
214 rds_ib_frag_free(ic, frag);
215 }
216 BUG_ON(!list_empty(&ibinc->ii_frags));
217
218 rdsdebug("freeing ibinc %p inc %p\n", ibinc, inc);
219 rds_ib_recv_cache_put(&ibinc->ii_cache_entry, &ic->i_cache_incs);
220}
221
222static void rds_ib_recv_clear_one(struct rds_ib_connection *ic,
223 struct rds_ib_recv_work *recv)
224{
225 if (recv->r_ibinc) {
226 rds_inc_put(&recv->r_ibinc->ii_inc);
227 recv->r_ibinc = NULL;
228 }
229 if (recv->r_frag) {
230 ib_dma_unmap_sg(ic->i_cm_id->device, &recv->r_frag->f_sg, 1, DMA_FROM_DEVICE);
231 rds_ib_frag_free(ic, recv->r_frag);
232 recv->r_frag = NULL;
233 }
234}
235
236void rds_ib_recv_clear_ring(struct rds_ib_connection *ic)
237{
238 u32 i;
239
240 for (i = 0; i < ic->i_recv_ring.w_nr; i++)
241 rds_ib_recv_clear_one(ic, &ic->i_recvs[i]);
242}
243
244static struct rds_ib_incoming *rds_ib_refill_one_inc(struct rds_ib_connection *ic,
245 gfp_t slab_mask)
246{
247 struct rds_ib_incoming *ibinc;
248 struct list_head *cache_item;
249 int avail_allocs;
250
251 cache_item = rds_ib_recv_cache_get(&ic->i_cache_incs);
252 if (cache_item) {
253 ibinc = container_of(cache_item, struct rds_ib_incoming, ii_cache_entry);
254 } else {
255 avail_allocs = atomic_add_unless(&rds_ib_allocation,
256 1, rds_ib_sysctl_max_recv_allocation);
257 if (!avail_allocs) {
258 rds_ib_stats_inc(s_ib_rx_alloc_limit);
259 return NULL;
260 }
261 ibinc = kmem_cache_alloc(rds_ib_incoming_slab, slab_mask);
262 if (!ibinc) {
263 atomic_dec(&rds_ib_allocation);
264 return NULL;
265 }
266 rds_ib_stats_inc(s_ib_rx_total_incs);
267 }
268 INIT_LIST_HEAD(&ibinc->ii_frags);
269 rds_inc_init(&ibinc->ii_inc, ic->conn, ic->conn->c_faddr);
270
271 return ibinc;
272}
273
274static struct rds_page_frag *rds_ib_refill_one_frag(struct rds_ib_connection *ic,
275 gfp_t slab_mask, gfp_t page_mask)
276{
277 struct rds_page_frag *frag;
278 struct list_head *cache_item;
279 int ret;
280
281 cache_item = rds_ib_recv_cache_get(&ic->i_cache_frags);
282 if (cache_item) {
283 frag = container_of(cache_item, struct rds_page_frag, f_cache_entry);
284 atomic_sub(RDS_FRAG_SIZE / SZ_1K, &ic->i_cache_allocs);
285 rds_ib_stats_add(s_ib_recv_added_to_cache, RDS_FRAG_SIZE);
286 } else {
287 frag = kmem_cache_alloc(rds_ib_frag_slab, slab_mask);
288 if (!frag)
289 return NULL;
290
291 sg_init_table(&frag->f_sg, 1);
292 ret = rds_page_remainder_alloc(&frag->f_sg,
293 RDS_FRAG_SIZE, page_mask);
294 if (ret) {
295 kmem_cache_free(rds_ib_frag_slab, frag);
296 return NULL;
297 }
298 rds_ib_stats_inc(s_ib_rx_total_frags);
299 }
300
301 INIT_LIST_HEAD(&frag->f_item);
302
303 return frag;
304}
305
306static int rds_ib_recv_refill_one(struct rds_connection *conn,
307 struct rds_ib_recv_work *recv, gfp_t gfp)
308{
309 struct rds_ib_connection *ic = conn->c_transport_data;
310 struct ib_sge *sge;
311 int ret = -ENOMEM;
312 gfp_t slab_mask = GFP_NOWAIT;
313 gfp_t page_mask = GFP_NOWAIT;
314
315 if (gfp & __GFP_DIRECT_RECLAIM) {
316 slab_mask = GFP_KERNEL;
317 page_mask = GFP_HIGHUSER;
318 }
319
320 if (!ic->i_cache_incs.ready)
321 rds_ib_cache_xfer_to_ready(&ic->i_cache_incs);
322 if (!ic->i_cache_frags.ready)
323 rds_ib_cache_xfer_to_ready(&ic->i_cache_frags);
324
325 /*
326 * ibinc was taken from recv if recv contained the start of a message.
327 * recvs that were continuations will still have this allocated.
328 */
329 if (!recv->r_ibinc) {
330 recv->r_ibinc = rds_ib_refill_one_inc(ic, slab_mask);
331 if (!recv->r_ibinc)
332 goto out;
333 }
334
335 WARN_ON(recv->r_frag); /* leak! */
336 recv->r_frag = rds_ib_refill_one_frag(ic, slab_mask, page_mask);
337 if (!recv->r_frag)
338 goto out;
339
340 ret = ib_dma_map_sg(ic->i_cm_id->device, &recv->r_frag->f_sg,
341 1, DMA_FROM_DEVICE);
342 WARN_ON(ret != 1);
343
344 sge = &recv->r_sge[0];
345 sge->addr = ic->i_recv_hdrs_dma + (recv - ic->i_recvs) * sizeof(struct rds_header);
346 sge->length = sizeof(struct rds_header);
347
348 sge = &recv->r_sge[1];
349 sge->addr = ib_sg_dma_address(ic->i_cm_id->device, &recv->r_frag->f_sg);
350 sge->length = ib_sg_dma_len(ic->i_cm_id->device, &recv->r_frag->f_sg);
351
352 ret = 0;
353out:
354 return ret;
355}
356
357static int acquire_refill(struct rds_connection *conn)
358{
359 return test_and_set_bit(RDS_RECV_REFILL, &conn->c_flags) == 0;
360}
361
362static void release_refill(struct rds_connection *conn)
363{
364 clear_bit(RDS_RECV_REFILL, &conn->c_flags);
365
366 /* We don't use wait_on_bit()/wake_up_bit() because our waking is in a
367 * hot path and finding waiters is very rare. We don't want to walk
368 * the system-wide hashed waitqueue buckets in the fast path only to
369 * almost never find waiters.
370 */
371 if (waitqueue_active(&conn->c_waitq))
372 wake_up_all(&conn->c_waitq);
373}
374
375/*
376 * This tries to allocate and post unused work requests after making sure that
377 * they have all the allocations they need to queue received fragments into
378 * sockets.
379 *
380 * -1 is returned if posting fails due to temporary resource exhaustion.
381 */
382void rds_ib_recv_refill(struct rds_connection *conn, int prefill, gfp_t gfp)
383{
384 struct rds_ib_connection *ic = conn->c_transport_data;
385 struct rds_ib_recv_work *recv;
386 struct ib_recv_wr *failed_wr;
387 unsigned int posted = 0;
388 int ret = 0;
389 bool can_wait = !!(gfp & __GFP_DIRECT_RECLAIM);
390 u32 pos;
391
392 /* the goal here is to just make sure that someone, somewhere
393 * is posting buffers. If we can't get the refill lock,
394 * let them do their thing
395 */
396 if (!acquire_refill(conn))
397 return;
398
399 while ((prefill || rds_conn_up(conn)) &&
400 rds_ib_ring_alloc(&ic->i_recv_ring, 1, &pos)) {
401 if (pos >= ic->i_recv_ring.w_nr) {
402 printk(KERN_NOTICE "Argh - ring alloc returned pos=%u\n",
403 pos);
404 break;
405 }
406
407 recv = &ic->i_recvs[pos];
408 ret = rds_ib_recv_refill_one(conn, recv, gfp);
409 if (ret) {
410 break;
411 }
412
413 rdsdebug("recv %p ibinc %p page %p addr %lu\n", recv,
414 recv->r_ibinc, sg_page(&recv->r_frag->f_sg),
415 (long) ib_sg_dma_address(
416 ic->i_cm_id->device,
417 &recv->r_frag->f_sg));
418
419 /* XXX when can this fail? */
420 ret = ib_post_recv(ic->i_cm_id->qp, &recv->r_wr, &failed_wr);
421 if (ret) {
422 rds_ib_conn_error(conn, "recv post on "
423 "%pI4 returned %d, disconnecting and "
424 "reconnecting\n", &conn->c_faddr,
425 ret);
426 break;
427 }
428
429 posted++;
430 }
431
432 /* We're doing flow control - update the window. */
433 if (ic->i_flowctl && posted)
434 rds_ib_advertise_credits(conn, posted);
435
436 if (ret)
437 rds_ib_ring_unalloc(&ic->i_recv_ring, 1);
438
439 release_refill(conn);
440
441 /* if we're called from the softirq handler, we'll be GFP_NOWAIT.
442 * in this case the ring being low is going to lead to more interrupts
443 * and we can safely let the softirq code take care of it unless the
444 * ring is completely empty.
445 *
446 * if we're called from krdsd, we'll be GFP_KERNEL. In this case
447 * we might have raced with the softirq code while we had the refill
448 * lock held. Use rds_ib_ring_low() instead of ring_empty to decide
449 * if we should requeue.
450 */
451 if (rds_conn_up(conn) &&
452 ((can_wait && rds_ib_ring_low(&ic->i_recv_ring)) ||
453 rds_ib_ring_empty(&ic->i_recv_ring))) {
454 queue_delayed_work(rds_wq, &conn->c_recv_w, 1);
455 }
456}
457
458/*
459 * We want to recycle several types of recv allocations, like incs and frags.
460 * To use this, the *_free() function passes in the ptr to a list_head within
461 * the recyclee, as well as the cache to put it on.
462 *
463 * First, we put the memory on a percpu list. When this reaches a certain size,
464 * We move it to an intermediate non-percpu list in a lockless manner, with some
465 * xchg/compxchg wizardry.
466 *
467 * N.B. Instead of a list_head as the anchor, we use a single pointer, which can
468 * be NULL and xchg'd. The list is actually empty when the pointer is NULL, and
469 * list_empty() will return true with one element is actually present.
470 */
471static void rds_ib_recv_cache_put(struct list_head *new_item,
472 struct rds_ib_refill_cache *cache)
473{
474 unsigned long flags;
475 struct list_head *old, *chpfirst;
476
477 local_irq_save(flags);
478
479 chpfirst = __this_cpu_read(cache->percpu->first);
480 if (!chpfirst)
481 INIT_LIST_HEAD(new_item);
482 else /* put on front */
483 list_add_tail(new_item, chpfirst);
484
485 __this_cpu_write(cache->percpu->first, new_item);
486 __this_cpu_inc(cache->percpu->count);
487
488 if (__this_cpu_read(cache->percpu->count) < RDS_IB_RECYCLE_BATCH_COUNT)
489 goto end;
490
491 /*
492 * Return our per-cpu first list to the cache's xfer by atomically
493 * grabbing the current xfer list, appending it to our per-cpu list,
494 * and then atomically returning that entire list back to the
495 * cache's xfer list as long as it's still empty.
496 */
497 do {
498 old = xchg(&cache->xfer, NULL);
499 if (old)
500 list_splice_entire_tail(old, chpfirst);
501 old = cmpxchg(&cache->xfer, NULL, chpfirst);
502 } while (old);
503
504
505 __this_cpu_write(cache->percpu->first, NULL);
506 __this_cpu_write(cache->percpu->count, 0);
507end:
508 local_irq_restore(flags);
509}
510
511static struct list_head *rds_ib_recv_cache_get(struct rds_ib_refill_cache *cache)
512{
513 struct list_head *head = cache->ready;
514
515 if (head) {
516 if (!list_empty(head)) {
517 cache->ready = head->next;
518 list_del_init(head);
519 } else
520 cache->ready = NULL;
521 }
522
523 return head;
524}
525
526int rds_ib_inc_copy_to_user(struct rds_incoming *inc, struct iov_iter *to)
527{
528 struct rds_ib_incoming *ibinc;
529 struct rds_page_frag *frag;
530 unsigned long to_copy;
531 unsigned long frag_off = 0;
532 int copied = 0;
533 int ret;
534 u32 len;
535
536 ibinc = container_of(inc, struct rds_ib_incoming, ii_inc);
537 frag = list_entry(ibinc->ii_frags.next, struct rds_page_frag, f_item);
538 len = be32_to_cpu(inc->i_hdr.h_len);
539
540 while (iov_iter_count(to) && copied < len) {
541 if (frag_off == RDS_FRAG_SIZE) {
542 frag = list_entry(frag->f_item.next,
543 struct rds_page_frag, f_item);
544 frag_off = 0;
545 }
546 to_copy = min_t(unsigned long, iov_iter_count(to),
547 RDS_FRAG_SIZE - frag_off);
548 to_copy = min_t(unsigned long, to_copy, len - copied);
549
550 /* XXX needs + offset for multiple recvs per page */
551 rds_stats_add(s_copy_to_user, to_copy);
552 ret = copy_page_to_iter(sg_page(&frag->f_sg),
553 frag->f_sg.offset + frag_off,
554 to_copy,
555 to);
556 if (ret != to_copy)
557 return -EFAULT;
558
559 frag_off += to_copy;
560 copied += to_copy;
561 }
562
563 return copied;
564}
565
566/* ic starts out kzalloc()ed */
567void rds_ib_recv_init_ack(struct rds_ib_connection *ic)
568{
569 struct ib_send_wr *wr = &ic->i_ack_wr;
570 struct ib_sge *sge = &ic->i_ack_sge;
571
572 sge->addr = ic->i_ack_dma;
573 sge->length = sizeof(struct rds_header);
574 sge->lkey = ic->i_pd->local_dma_lkey;
575
576 wr->sg_list = sge;
577 wr->num_sge = 1;
578 wr->opcode = IB_WR_SEND;
579 wr->wr_id = RDS_IB_ACK_WR_ID;
580 wr->send_flags = IB_SEND_SIGNALED | IB_SEND_SOLICITED;
581}
582
583/*
584 * You'd think that with reliable IB connections you wouldn't need to ack
585 * messages that have been received. The problem is that IB hardware generates
586 * an ack message before it has DMAed the message into memory. This creates a
587 * potential message loss if the HCA is disabled for any reason between when it
588 * sends the ack and before the message is DMAed and processed. This is only a
589 * potential issue if another HCA is available for fail-over.
590 *
591 * When the remote host receives our ack they'll free the sent message from
592 * their send queue. To decrease the latency of this we always send an ack
593 * immediately after we've received messages.
594 *
595 * For simplicity, we only have one ack in flight at a time. This puts
596 * pressure on senders to have deep enough send queues to absorb the latency of
597 * a single ack frame being in flight. This might not be good enough.
598 *
599 * This is implemented by have a long-lived send_wr and sge which point to a
600 * statically allocated ack frame. This ack wr does not fall under the ring
601 * accounting that the tx and rx wrs do. The QP attribute specifically makes
602 * room for it beyond the ring size. Send completion notices its special
603 * wr_id and avoids working with the ring in that case.
604 */
605#ifndef KERNEL_HAS_ATOMIC64
606void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq, int ack_required)
607{
608 unsigned long flags;
609
610 spin_lock_irqsave(&ic->i_ack_lock, flags);
611 ic->i_ack_next = seq;
612 if (ack_required)
613 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
614 spin_unlock_irqrestore(&ic->i_ack_lock, flags);
615}
616
617static u64 rds_ib_get_ack(struct rds_ib_connection *ic)
618{
619 unsigned long flags;
620 u64 seq;
621
622 clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
623
624 spin_lock_irqsave(&ic->i_ack_lock, flags);
625 seq = ic->i_ack_next;
626 spin_unlock_irqrestore(&ic->i_ack_lock, flags);
627
628 return seq;
629}
630#else
631void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq, int ack_required)
632{
633 atomic64_set(&ic->i_ack_next, seq);
634 if (ack_required) {
635 smp_mb__before_atomic();
636 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
637 }
638}
639
640static u64 rds_ib_get_ack(struct rds_ib_connection *ic)
641{
642 clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
643 smp_mb__after_atomic();
644
645 return atomic64_read(&ic->i_ack_next);
646}
647#endif
648
649
650static void rds_ib_send_ack(struct rds_ib_connection *ic, unsigned int adv_credits)
651{
652 struct rds_header *hdr = ic->i_ack;
653 struct ib_send_wr *failed_wr;
654 u64 seq;
655 int ret;
656
657 seq = rds_ib_get_ack(ic);
658
659 rdsdebug("send_ack: ic %p ack %llu\n", ic, (unsigned long long) seq);
660 rds_message_populate_header(hdr, 0, 0, 0);
661 hdr->h_ack = cpu_to_be64(seq);
662 hdr->h_credit = adv_credits;
663 rds_message_make_checksum(hdr);
664 ic->i_ack_queued = jiffies;
665
666 ret = ib_post_send(ic->i_cm_id->qp, &ic->i_ack_wr, &failed_wr);
667 if (unlikely(ret)) {
668 /* Failed to send. Release the WR, and
669 * force another ACK.
670 */
671 clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
672 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
673
674 rds_ib_stats_inc(s_ib_ack_send_failure);
675
676 rds_ib_conn_error(ic->conn, "sending ack failed\n");
677 } else
678 rds_ib_stats_inc(s_ib_ack_sent);
679}
680
681/*
682 * There are 3 ways of getting acknowledgements to the peer:
683 * 1. We call rds_ib_attempt_ack from the recv completion handler
684 * to send an ACK-only frame.
685 * However, there can be only one such frame in the send queue
686 * at any time, so we may have to postpone it.
687 * 2. When another (data) packet is transmitted while there's
688 * an ACK in the queue, we piggyback the ACK sequence number
689 * on the data packet.
690 * 3. If the ACK WR is done sending, we get called from the
691 * send queue completion handler, and check whether there's
692 * another ACK pending (postponed because the WR was on the
693 * queue). If so, we transmit it.
694 *
695 * We maintain 2 variables:
696 * - i_ack_flags, which keeps track of whether the ACK WR
697 * is currently in the send queue or not (IB_ACK_IN_FLIGHT)
698 * - i_ack_next, which is the last sequence number we received
699 *
700 * Potentially, send queue and receive queue handlers can run concurrently.
701 * It would be nice to not have to use a spinlock to synchronize things,
702 * but the one problem that rules this out is that 64bit updates are
703 * not atomic on all platforms. Things would be a lot simpler if
704 * we had atomic64 or maybe cmpxchg64 everywhere.
705 *
706 * Reconnecting complicates this picture just slightly. When we
707 * reconnect, we may be seeing duplicate packets. The peer
708 * is retransmitting them, because it hasn't seen an ACK for
709 * them. It is important that we ACK these.
710 *
711 * ACK mitigation adds a header flag "ACK_REQUIRED"; any packet with
712 * this flag set *MUST* be acknowledged immediately.
713 */
714
715/*
716 * When we get here, we're called from the recv queue handler.
717 * Check whether we ought to transmit an ACK.
718 */
719void rds_ib_attempt_ack(struct rds_ib_connection *ic)
720{
721 unsigned int adv_credits;
722
723 if (!test_bit(IB_ACK_REQUESTED, &ic->i_ack_flags))
724 return;
725
726 if (test_and_set_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags)) {
727 rds_ib_stats_inc(s_ib_ack_send_delayed);
728 return;
729 }
730
731 /* Can we get a send credit? */
732 if (!rds_ib_send_grab_credits(ic, 1, &adv_credits, 0, RDS_MAX_ADV_CREDIT)) {
733 rds_ib_stats_inc(s_ib_tx_throttle);
734 clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
735 return;
736 }
737
738 clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
739 rds_ib_send_ack(ic, adv_credits);
740}
741
742/*
743 * We get here from the send completion handler, when the
744 * adapter tells us the ACK frame was sent.
745 */
746void rds_ib_ack_send_complete(struct rds_ib_connection *ic)
747{
748 clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
749 rds_ib_attempt_ack(ic);
750}
751
752/*
753 * This is called by the regular xmit code when it wants to piggyback
754 * an ACK on an outgoing frame.
755 */
756u64 rds_ib_piggyb_ack(struct rds_ib_connection *ic)
757{
758 if (test_and_clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags))
759 rds_ib_stats_inc(s_ib_ack_send_piggybacked);
760 return rds_ib_get_ack(ic);
761}
762
763/*
764 * It's kind of lame that we're copying from the posted receive pages into
765 * long-lived bitmaps. We could have posted the bitmaps and rdma written into
766 * them. But receiving new congestion bitmaps should be a *rare* event, so
767 * hopefully we won't need to invest that complexity in making it more
768 * efficient. By copying we can share a simpler core with TCP which has to
769 * copy.
770 */
771static void rds_ib_cong_recv(struct rds_connection *conn,
772 struct rds_ib_incoming *ibinc)
773{
774 struct rds_cong_map *map;
775 unsigned int map_off;
776 unsigned int map_page;
777 struct rds_page_frag *frag;
778 unsigned long frag_off;
779 unsigned long to_copy;
780 unsigned long copied;
781 uint64_t uncongested = 0;
782 void *addr;
783
784 /* catch completely corrupt packets */
785 if (be32_to_cpu(ibinc->ii_inc.i_hdr.h_len) != RDS_CONG_MAP_BYTES)
786 return;
787
788 map = conn->c_fcong;
789 map_page = 0;
790 map_off = 0;
791
792 frag = list_entry(ibinc->ii_frags.next, struct rds_page_frag, f_item);
793 frag_off = 0;
794
795 copied = 0;
796
797 while (copied < RDS_CONG_MAP_BYTES) {
798 uint64_t *src, *dst;
799 unsigned int k;
800
801 to_copy = min(RDS_FRAG_SIZE - frag_off, PAGE_SIZE - map_off);
802 BUG_ON(to_copy & 7); /* Must be 64bit aligned. */
803
804 addr = kmap_atomic(sg_page(&frag->f_sg));
805
806 src = addr + frag->f_sg.offset + frag_off;
807 dst = (void *)map->m_page_addrs[map_page] + map_off;
808 for (k = 0; k < to_copy; k += 8) {
809 /* Record ports that became uncongested, ie
810 * bits that changed from 0 to 1. */
811 uncongested |= ~(*src) & *dst;
812 *dst++ = *src++;
813 }
814 kunmap_atomic(addr);
815
816 copied += to_copy;
817
818 map_off += to_copy;
819 if (map_off == PAGE_SIZE) {
820 map_off = 0;
821 map_page++;
822 }
823
824 frag_off += to_copy;
825 if (frag_off == RDS_FRAG_SIZE) {
826 frag = list_entry(frag->f_item.next,
827 struct rds_page_frag, f_item);
828 frag_off = 0;
829 }
830 }
831
832 /* the congestion map is in little endian order */
833 uncongested = le64_to_cpu(uncongested);
834
835 rds_cong_map_updated(map, uncongested);
836}
837
838static void rds_ib_process_recv(struct rds_connection *conn,
839 struct rds_ib_recv_work *recv, u32 data_len,
840 struct rds_ib_ack_state *state)
841{
842 struct rds_ib_connection *ic = conn->c_transport_data;
843 struct rds_ib_incoming *ibinc = ic->i_ibinc;
844 struct rds_header *ihdr, *hdr;
845
846 /* XXX shut down the connection if port 0,0 are seen? */
847
848 rdsdebug("ic %p ibinc %p recv %p byte len %u\n", ic, ibinc, recv,
849 data_len);
850
851 if (data_len < sizeof(struct rds_header)) {
852 rds_ib_conn_error(conn, "incoming message "
853 "from %pI4 didn't include a "
854 "header, disconnecting and "
855 "reconnecting\n",
856 &conn->c_faddr);
857 return;
858 }
859 data_len -= sizeof(struct rds_header);
860
861 ihdr = &ic->i_recv_hdrs[recv - ic->i_recvs];
862
863 /* Validate the checksum. */
864 if (!rds_message_verify_checksum(ihdr)) {
865 rds_ib_conn_error(conn, "incoming message "
866 "from %pI4 has corrupted header - "
867 "forcing a reconnect\n",
868 &conn->c_faddr);
869 rds_stats_inc(s_recv_drop_bad_checksum);
870 return;
871 }
872
873 /* Process the ACK sequence which comes with every packet */
874 state->ack_recv = be64_to_cpu(ihdr->h_ack);
875 state->ack_recv_valid = 1;
876
877 /* Process the credits update if there was one */
878 if (ihdr->h_credit)
879 rds_ib_send_add_credits(conn, ihdr->h_credit);
880
881 if (ihdr->h_sport == 0 && ihdr->h_dport == 0 && data_len == 0) {
882 /* This is an ACK-only packet. The fact that it gets
883 * special treatment here is that historically, ACKs
884 * were rather special beasts.
885 */
886 rds_ib_stats_inc(s_ib_ack_received);
887
888 /*
889 * Usually the frags make their way on to incs and are then freed as
890 * the inc is freed. We don't go that route, so we have to drop the
891 * page ref ourselves. We can't just leave the page on the recv
892 * because that confuses the dma mapping of pages and each recv's use
893 * of a partial page.
894 *
895 * FIXME: Fold this into the code path below.
896 */
897 rds_ib_frag_free(ic, recv->r_frag);
898 recv->r_frag = NULL;
899 return;
900 }
901
902 /*
903 * If we don't already have an inc on the connection then this
904 * fragment has a header and starts a message.. copy its header
905 * into the inc and save the inc so we can hang upcoming fragments
906 * off its list.
907 */
908 if (!ibinc) {
909 ibinc = recv->r_ibinc;
910 recv->r_ibinc = NULL;
911 ic->i_ibinc = ibinc;
912
913 hdr = &ibinc->ii_inc.i_hdr;
914 ibinc->ii_inc.i_rx_lat_trace[RDS_MSG_RX_HDR] =
915 local_clock();
916 memcpy(hdr, ihdr, sizeof(*hdr));
917 ic->i_recv_data_rem = be32_to_cpu(hdr->h_len);
918 ibinc->ii_inc.i_rx_lat_trace[RDS_MSG_RX_START] =
919 local_clock();
920
921 rdsdebug("ic %p ibinc %p rem %u flag 0x%x\n", ic, ibinc,
922 ic->i_recv_data_rem, hdr->h_flags);
923 } else {
924 hdr = &ibinc->ii_inc.i_hdr;
925 /* We can't just use memcmp here; fragments of a
926 * single message may carry different ACKs */
927 if (hdr->h_sequence != ihdr->h_sequence ||
928 hdr->h_len != ihdr->h_len ||
929 hdr->h_sport != ihdr->h_sport ||
930 hdr->h_dport != ihdr->h_dport) {
931 rds_ib_conn_error(conn,
932 "fragment header mismatch; forcing reconnect\n");
933 return;
934 }
935 }
936
937 list_add_tail(&recv->r_frag->f_item, &ibinc->ii_frags);
938 recv->r_frag = NULL;
939
940 if (ic->i_recv_data_rem > RDS_FRAG_SIZE)
941 ic->i_recv_data_rem -= RDS_FRAG_SIZE;
942 else {
943 ic->i_recv_data_rem = 0;
944 ic->i_ibinc = NULL;
945
946 if (ibinc->ii_inc.i_hdr.h_flags == RDS_FLAG_CONG_BITMAP)
947 rds_ib_cong_recv(conn, ibinc);
948 else {
949 rds_recv_incoming(conn, conn->c_faddr, conn->c_laddr,
950 &ibinc->ii_inc, GFP_ATOMIC);
951 state->ack_next = be64_to_cpu(hdr->h_sequence);
952 state->ack_next_valid = 1;
953 }
954
955 /* Evaluate the ACK_REQUIRED flag *after* we received
956 * the complete frame, and after bumping the next_rx
957 * sequence. */
958 if (hdr->h_flags & RDS_FLAG_ACK_REQUIRED) {
959 rds_stats_inc(s_recv_ack_required);
960 state->ack_required = 1;
961 }
962
963 rds_inc_put(&ibinc->ii_inc);
964 }
965}
966
967void rds_ib_recv_cqe_handler(struct rds_ib_connection *ic,
968 struct ib_wc *wc,
969 struct rds_ib_ack_state *state)
970{
971 struct rds_connection *conn = ic->conn;
972 struct rds_ib_recv_work *recv;
973
974 rdsdebug("wc wr_id 0x%llx status %u (%s) byte_len %u imm_data %u\n",
975 (unsigned long long)wc->wr_id, wc->status,
976 ib_wc_status_msg(wc->status), wc->byte_len,
977 be32_to_cpu(wc->ex.imm_data));
978
979 rds_ib_stats_inc(s_ib_rx_cq_event);
980 recv = &ic->i_recvs[rds_ib_ring_oldest(&ic->i_recv_ring)];
981 ib_dma_unmap_sg(ic->i_cm_id->device, &recv->r_frag->f_sg, 1,
982 DMA_FROM_DEVICE);
983
984 /* Also process recvs in connecting state because it is possible
985 * to get a recv completion _before_ the rdmacm ESTABLISHED
986 * event is processed.
987 */
988 if (wc->status == IB_WC_SUCCESS) {
989 rds_ib_process_recv(conn, recv, wc->byte_len, state);
990 } else {
991 /* We expect errors as the qp is drained during shutdown */
992 if (rds_conn_up(conn) || rds_conn_connecting(conn))
993 rds_ib_conn_error(conn, "recv completion on <%pI4,%pI4> had status %u (%s), disconnecting and reconnecting\n",
994 &conn->c_laddr, &conn->c_faddr,
995 wc->status,
996 ib_wc_status_msg(wc->status));
997 }
998
999 /* rds_ib_process_recv() doesn't always consume the frag, and
1000 * we might not have called it at all if the wc didn't indicate
1001 * success. We already unmapped the frag's pages, though, and
1002 * the following rds_ib_ring_free() call tells the refill path
1003 * that it will not find an allocated frag here. Make sure we
1004 * keep that promise by freeing a frag that's still on the ring.
1005 */
1006 if (recv->r_frag) {
1007 rds_ib_frag_free(ic, recv->r_frag);
1008 recv->r_frag = NULL;
1009 }
1010 rds_ib_ring_free(&ic->i_recv_ring, 1);
1011
1012 /* If we ever end up with a really empty receive ring, we're
1013 * in deep trouble, as the sender will definitely see RNR
1014 * timeouts. */
1015 if (rds_ib_ring_empty(&ic->i_recv_ring))
1016 rds_ib_stats_inc(s_ib_rx_ring_empty);
1017
1018 if (rds_ib_ring_low(&ic->i_recv_ring)) {
1019 rds_ib_recv_refill(conn, 0, GFP_NOWAIT);
1020 rds_ib_stats_inc(s_ib_rx_refill_from_cq);
1021 }
1022}
1023
1024int rds_ib_recv_path(struct rds_conn_path *cp)
1025{
1026 struct rds_connection *conn = cp->cp_conn;
1027 struct rds_ib_connection *ic = conn->c_transport_data;
1028 int ret = 0;
1029
1030 rdsdebug("conn %p\n", conn);
1031 if (rds_conn_up(conn)) {
1032 rds_ib_attempt_ack(ic);
1033 rds_ib_recv_refill(conn, 0, GFP_KERNEL);
1034 rds_ib_stats_inc(s_ib_rx_refill_from_thread);
1035 }
1036
1037 return ret;
1038}
1039
1040int rds_ib_recv_init(void)
1041{
1042 struct sysinfo si;
1043 int ret = -ENOMEM;
1044
1045 /* Default to 30% of all available RAM for recv memory */
1046 si_meminfo(&si);
1047 rds_ib_sysctl_max_recv_allocation = si.totalram / 3 * PAGE_SIZE / RDS_FRAG_SIZE;
1048
1049 rds_ib_incoming_slab = kmem_cache_create("rds_ib_incoming",
1050 sizeof(struct rds_ib_incoming),
1051 0, SLAB_HWCACHE_ALIGN, NULL);
1052 if (!rds_ib_incoming_slab)
1053 goto out;
1054
1055 rds_ib_frag_slab = kmem_cache_create("rds_ib_frag",
1056 sizeof(struct rds_page_frag),
1057 0, SLAB_HWCACHE_ALIGN, NULL);
1058 if (!rds_ib_frag_slab) {
1059 kmem_cache_destroy(rds_ib_incoming_slab);
1060 rds_ib_incoming_slab = NULL;
1061 } else
1062 ret = 0;
1063out:
1064 return ret;
1065}
1066
1067void rds_ib_recv_exit(void)
1068{
1069 kmem_cache_destroy(rds_ib_incoming_slab);
1070 kmem_cache_destroy(rds_ib_frag_slab);
1071}