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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_pd->local_dma_lkey;
66
67 sge = &recv->r_sge[1];
68 sge->addr = 0;
69 sge->length = RDS_FRAG_SIZE;
70 sge->lkey = ic->i_pd->local_dma_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, gfp_t gfp)
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 (gfp & __GFP_DIRECT_RECLAIM) {
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 = ib_sg_dma_address(ic->i_cm_id->device, &recv->r_frag->f_sg);
343 sge->length = ib_sg_dma_len(ic->i_cm_id->device, &recv->r_frag->f_sg);
344
345 ret = 0;
346out:
347 return ret;
348}
349
350static int acquire_refill(struct rds_connection *conn)
351{
352 return test_and_set_bit(RDS_RECV_REFILL, &conn->c_flags) == 0;
353}
354
355static void release_refill(struct rds_connection *conn)
356{
357 clear_bit(RDS_RECV_REFILL, &conn->c_flags);
358
359 /* We don't use wait_on_bit()/wake_up_bit() because our waking is in a
360 * hot path and finding waiters is very rare. We don't want to walk
361 * the system-wide hashed waitqueue buckets in the fast path only to
362 * almost never find waiters.
363 */
364 if (waitqueue_active(&conn->c_waitq))
365 wake_up_all(&conn->c_waitq);
366}
367
368/*
369 * This tries to allocate and post unused work requests after making sure that
370 * they have all the allocations they need to queue received fragments into
371 * sockets.
372 *
373 * -1 is returned if posting fails due to temporary resource exhaustion.
374 */
375void rds_ib_recv_refill(struct rds_connection *conn, int prefill, gfp_t gfp)
376{
377 struct rds_ib_connection *ic = conn->c_transport_data;
378 struct rds_ib_recv_work *recv;
379 struct ib_recv_wr *failed_wr;
380 unsigned int posted = 0;
381 int ret = 0;
382 bool can_wait = !!(gfp & __GFP_DIRECT_RECLAIM);
383 u32 pos;
384
385 /* the goal here is to just make sure that someone, somewhere
386 * is posting buffers. If we can't get the refill lock,
387 * let them do their thing
388 */
389 if (!acquire_refill(conn))
390 return;
391
392 while ((prefill || rds_conn_up(conn)) &&
393 rds_ib_ring_alloc(&ic->i_recv_ring, 1, &pos)) {
394 if (pos >= ic->i_recv_ring.w_nr) {
395 printk(KERN_NOTICE "Argh - ring alloc returned pos=%u\n",
396 pos);
397 break;
398 }
399
400 recv = &ic->i_recvs[pos];
401 ret = rds_ib_recv_refill_one(conn, recv, gfp);
402 if (ret) {
403 break;
404 }
405
406 /* XXX when can this fail? */
407 ret = ib_post_recv(ic->i_cm_id->qp, &recv->r_wr, &failed_wr);
408 rdsdebug("recv %p ibinc %p page %p addr %lu ret %d\n", recv,
409 recv->r_ibinc, sg_page(&recv->r_frag->f_sg),
410 (long) ib_sg_dma_address(
411 ic->i_cm_id->device,
412 &recv->r_frag->f_sg),
413 ret);
414 if (ret) {
415 rds_ib_conn_error(conn, "recv post on "
416 "%pI4 returned %d, disconnecting and "
417 "reconnecting\n", &conn->c_faddr,
418 ret);
419 break;
420 }
421
422 posted++;
423 }
424
425 /* We're doing flow control - update the window. */
426 if (ic->i_flowctl && posted)
427 rds_ib_advertise_credits(conn, posted);
428
429 if (ret)
430 rds_ib_ring_unalloc(&ic->i_recv_ring, 1);
431
432 release_refill(conn);
433
434 /* if we're called from the softirq handler, we'll be GFP_NOWAIT.
435 * in this case the ring being low is going to lead to more interrupts
436 * and we can safely let the softirq code take care of it unless the
437 * ring is completely empty.
438 *
439 * if we're called from krdsd, we'll be GFP_KERNEL. In this case
440 * we might have raced with the softirq code while we had the refill
441 * lock held. Use rds_ib_ring_low() instead of ring_empty to decide
442 * if we should requeue.
443 */
444 if (rds_conn_up(conn) &&
445 ((can_wait && rds_ib_ring_low(&ic->i_recv_ring)) ||
446 rds_ib_ring_empty(&ic->i_recv_ring))) {
447 queue_delayed_work(rds_wq, &conn->c_recv_w, 1);
448 }
449}
450
451/*
452 * We want to recycle several types of recv allocations, like incs and frags.
453 * To use this, the *_free() function passes in the ptr to a list_head within
454 * the recyclee, as well as the cache to put it on.
455 *
456 * First, we put the memory on a percpu list. When this reaches a certain size,
457 * We move it to an intermediate non-percpu list in a lockless manner, with some
458 * xchg/compxchg wizardry.
459 *
460 * N.B. Instead of a list_head as the anchor, we use a single pointer, which can
461 * be NULL and xchg'd. The list is actually empty when the pointer is NULL, and
462 * list_empty() will return true with one element is actually present.
463 */
464static void rds_ib_recv_cache_put(struct list_head *new_item,
465 struct rds_ib_refill_cache *cache)
466{
467 unsigned long flags;
468 struct list_head *old, *chpfirst;
469
470 local_irq_save(flags);
471
472 chpfirst = __this_cpu_read(cache->percpu->first);
473 if (!chpfirst)
474 INIT_LIST_HEAD(new_item);
475 else /* put on front */
476 list_add_tail(new_item, chpfirst);
477
478 __this_cpu_write(cache->percpu->first, new_item);
479 __this_cpu_inc(cache->percpu->count);
480
481 if (__this_cpu_read(cache->percpu->count) < RDS_IB_RECYCLE_BATCH_COUNT)
482 goto end;
483
484 /*
485 * Return our per-cpu first list to the cache's xfer by atomically
486 * grabbing the current xfer list, appending it to our per-cpu list,
487 * and then atomically returning that entire list back to the
488 * cache's xfer list as long as it's still empty.
489 */
490 do {
491 old = xchg(&cache->xfer, NULL);
492 if (old)
493 list_splice_entire_tail(old, chpfirst);
494 old = cmpxchg(&cache->xfer, NULL, chpfirst);
495 } while (old);
496
497
498 __this_cpu_write(cache->percpu->first, NULL);
499 __this_cpu_write(cache->percpu->count, 0);
500end:
501 local_irq_restore(flags);
502}
503
504static struct list_head *rds_ib_recv_cache_get(struct rds_ib_refill_cache *cache)
505{
506 struct list_head *head = cache->ready;
507
508 if (head) {
509 if (!list_empty(head)) {
510 cache->ready = head->next;
511 list_del_init(head);
512 } else
513 cache->ready = NULL;
514 }
515
516 return head;
517}
518
519int rds_ib_inc_copy_to_user(struct rds_incoming *inc, struct iov_iter *to)
520{
521 struct rds_ib_incoming *ibinc;
522 struct rds_page_frag *frag;
523 unsigned long to_copy;
524 unsigned long frag_off = 0;
525 int copied = 0;
526 int ret;
527 u32 len;
528
529 ibinc = container_of(inc, struct rds_ib_incoming, ii_inc);
530 frag = list_entry(ibinc->ii_frags.next, struct rds_page_frag, f_item);
531 len = be32_to_cpu(inc->i_hdr.h_len);
532
533 while (iov_iter_count(to) && copied < len) {
534 if (frag_off == RDS_FRAG_SIZE) {
535 frag = list_entry(frag->f_item.next,
536 struct rds_page_frag, f_item);
537 frag_off = 0;
538 }
539 to_copy = min_t(unsigned long, iov_iter_count(to),
540 RDS_FRAG_SIZE - frag_off);
541 to_copy = min_t(unsigned long, to_copy, len - copied);
542
543 /* XXX needs + offset for multiple recvs per page */
544 rds_stats_add(s_copy_to_user, to_copy);
545 ret = copy_page_to_iter(sg_page(&frag->f_sg),
546 frag->f_sg.offset + frag_off,
547 to_copy,
548 to);
549 if (ret != to_copy)
550 return -EFAULT;
551
552 frag_off += to_copy;
553 copied += to_copy;
554 }
555
556 return copied;
557}
558
559/* ic starts out kzalloc()ed */
560void rds_ib_recv_init_ack(struct rds_ib_connection *ic)
561{
562 struct ib_send_wr *wr = &ic->i_ack_wr;
563 struct ib_sge *sge = &ic->i_ack_sge;
564
565 sge->addr = ic->i_ack_dma;
566 sge->length = sizeof(struct rds_header);
567 sge->lkey = ic->i_pd->local_dma_lkey;
568
569 wr->sg_list = sge;
570 wr->num_sge = 1;
571 wr->opcode = IB_WR_SEND;
572 wr->wr_id = RDS_IB_ACK_WR_ID;
573 wr->send_flags = IB_SEND_SIGNALED | IB_SEND_SOLICITED;
574}
575
576/*
577 * You'd think that with reliable IB connections you wouldn't need to ack
578 * messages that have been received. The problem is that IB hardware generates
579 * an ack message before it has DMAed the message into memory. This creates a
580 * potential message loss if the HCA is disabled for any reason between when it
581 * sends the ack and before the message is DMAed and processed. This is only a
582 * potential issue if another HCA is available for fail-over.
583 *
584 * When the remote host receives our ack they'll free the sent message from
585 * their send queue. To decrease the latency of this we always send an ack
586 * immediately after we've received messages.
587 *
588 * For simplicity, we only have one ack in flight at a time. This puts
589 * pressure on senders to have deep enough send queues to absorb the latency of
590 * a single ack frame being in flight. This might not be good enough.
591 *
592 * This is implemented by have a long-lived send_wr and sge which point to a
593 * statically allocated ack frame. This ack wr does not fall under the ring
594 * accounting that the tx and rx wrs do. The QP attribute specifically makes
595 * room for it beyond the ring size. Send completion notices its special
596 * wr_id and avoids working with the ring in that case.
597 */
598#ifndef KERNEL_HAS_ATOMIC64
599void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq, int ack_required)
600{
601 unsigned long flags;
602
603 spin_lock_irqsave(&ic->i_ack_lock, flags);
604 ic->i_ack_next = seq;
605 if (ack_required)
606 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
607 spin_unlock_irqrestore(&ic->i_ack_lock, flags);
608}
609
610static u64 rds_ib_get_ack(struct rds_ib_connection *ic)
611{
612 unsigned long flags;
613 u64 seq;
614
615 clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
616
617 spin_lock_irqsave(&ic->i_ack_lock, flags);
618 seq = ic->i_ack_next;
619 spin_unlock_irqrestore(&ic->i_ack_lock, flags);
620
621 return seq;
622}
623#else
624void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq, int ack_required)
625{
626 atomic64_set(&ic->i_ack_next, seq);
627 if (ack_required) {
628 smp_mb__before_atomic();
629 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
630 }
631}
632
633static u64 rds_ib_get_ack(struct rds_ib_connection *ic)
634{
635 clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
636 smp_mb__after_atomic();
637
638 return atomic64_read(&ic->i_ack_next);
639}
640#endif
641
642
643static void rds_ib_send_ack(struct rds_ib_connection *ic, unsigned int adv_credits)
644{
645 struct rds_header *hdr = ic->i_ack;
646 struct ib_send_wr *failed_wr;
647 u64 seq;
648 int ret;
649
650 seq = rds_ib_get_ack(ic);
651
652 rdsdebug("send_ack: ic %p ack %llu\n", ic, (unsigned long long) seq);
653 rds_message_populate_header(hdr, 0, 0, 0);
654 hdr->h_ack = cpu_to_be64(seq);
655 hdr->h_credit = adv_credits;
656 rds_message_make_checksum(hdr);
657 ic->i_ack_queued = jiffies;
658
659 ret = ib_post_send(ic->i_cm_id->qp, &ic->i_ack_wr, &failed_wr);
660 if (unlikely(ret)) {
661 /* Failed to send. Release the WR, and
662 * force another ACK.
663 */
664 clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
665 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
666
667 rds_ib_stats_inc(s_ib_ack_send_failure);
668
669 rds_ib_conn_error(ic->conn, "sending ack failed\n");
670 } else
671 rds_ib_stats_inc(s_ib_ack_sent);
672}
673
674/*
675 * There are 3 ways of getting acknowledgements to the peer:
676 * 1. We call rds_ib_attempt_ack from the recv completion handler
677 * to send an ACK-only frame.
678 * However, there can be only one such frame in the send queue
679 * at any time, so we may have to postpone it.
680 * 2. When another (data) packet is transmitted while there's
681 * an ACK in the queue, we piggyback the ACK sequence number
682 * on the data packet.
683 * 3. If the ACK WR is done sending, we get called from the
684 * send queue completion handler, and check whether there's
685 * another ACK pending (postponed because the WR was on the
686 * queue). If so, we transmit it.
687 *
688 * We maintain 2 variables:
689 * - i_ack_flags, which keeps track of whether the ACK WR
690 * is currently in the send queue or not (IB_ACK_IN_FLIGHT)
691 * - i_ack_next, which is the last sequence number we received
692 *
693 * Potentially, send queue and receive queue handlers can run concurrently.
694 * It would be nice to not have to use a spinlock to synchronize things,
695 * but the one problem that rules this out is that 64bit updates are
696 * not atomic on all platforms. Things would be a lot simpler if
697 * we had atomic64 or maybe cmpxchg64 everywhere.
698 *
699 * Reconnecting complicates this picture just slightly. When we
700 * reconnect, we may be seeing duplicate packets. The peer
701 * is retransmitting them, because it hasn't seen an ACK for
702 * them. It is important that we ACK these.
703 *
704 * ACK mitigation adds a header flag "ACK_REQUIRED"; any packet with
705 * this flag set *MUST* be acknowledged immediately.
706 */
707
708/*
709 * When we get here, we're called from the recv queue handler.
710 * Check whether we ought to transmit an ACK.
711 */
712void rds_ib_attempt_ack(struct rds_ib_connection *ic)
713{
714 unsigned int adv_credits;
715
716 if (!test_bit(IB_ACK_REQUESTED, &ic->i_ack_flags))
717 return;
718
719 if (test_and_set_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags)) {
720 rds_ib_stats_inc(s_ib_ack_send_delayed);
721 return;
722 }
723
724 /* Can we get a send credit? */
725 if (!rds_ib_send_grab_credits(ic, 1, &adv_credits, 0, RDS_MAX_ADV_CREDIT)) {
726 rds_ib_stats_inc(s_ib_tx_throttle);
727 clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
728 return;
729 }
730
731 clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
732 rds_ib_send_ack(ic, adv_credits);
733}
734
735/*
736 * We get here from the send completion handler, when the
737 * adapter tells us the ACK frame was sent.
738 */
739void rds_ib_ack_send_complete(struct rds_ib_connection *ic)
740{
741 clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
742 rds_ib_attempt_ack(ic);
743}
744
745/*
746 * This is called by the regular xmit code when it wants to piggyback
747 * an ACK on an outgoing frame.
748 */
749u64 rds_ib_piggyb_ack(struct rds_ib_connection *ic)
750{
751 if (test_and_clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags))
752 rds_ib_stats_inc(s_ib_ack_send_piggybacked);
753 return rds_ib_get_ack(ic);
754}
755
756/*
757 * It's kind of lame that we're copying from the posted receive pages into
758 * long-lived bitmaps. We could have posted the bitmaps and rdma written into
759 * them. But receiving new congestion bitmaps should be a *rare* event, so
760 * hopefully we won't need to invest that complexity in making it more
761 * efficient. By copying we can share a simpler core with TCP which has to
762 * copy.
763 */
764static void rds_ib_cong_recv(struct rds_connection *conn,
765 struct rds_ib_incoming *ibinc)
766{
767 struct rds_cong_map *map;
768 unsigned int map_off;
769 unsigned int map_page;
770 struct rds_page_frag *frag;
771 unsigned long frag_off;
772 unsigned long to_copy;
773 unsigned long copied;
774 uint64_t uncongested = 0;
775 void *addr;
776
777 /* catch completely corrupt packets */
778 if (be32_to_cpu(ibinc->ii_inc.i_hdr.h_len) != RDS_CONG_MAP_BYTES)
779 return;
780
781 map = conn->c_fcong;
782 map_page = 0;
783 map_off = 0;
784
785 frag = list_entry(ibinc->ii_frags.next, struct rds_page_frag, f_item);
786 frag_off = 0;
787
788 copied = 0;
789
790 while (copied < RDS_CONG_MAP_BYTES) {
791 uint64_t *src, *dst;
792 unsigned int k;
793
794 to_copy = min(RDS_FRAG_SIZE - frag_off, PAGE_SIZE - map_off);
795 BUG_ON(to_copy & 7); /* Must be 64bit aligned. */
796
797 addr = kmap_atomic(sg_page(&frag->f_sg));
798
799 src = addr + frag->f_sg.offset + frag_off;
800 dst = (void *)map->m_page_addrs[map_page] + map_off;
801 for (k = 0; k < to_copy; k += 8) {
802 /* Record ports that became uncongested, ie
803 * bits that changed from 0 to 1. */
804 uncongested |= ~(*src) & *dst;
805 *dst++ = *src++;
806 }
807 kunmap_atomic(addr);
808
809 copied += to_copy;
810
811 map_off += to_copy;
812 if (map_off == PAGE_SIZE) {
813 map_off = 0;
814 map_page++;
815 }
816
817 frag_off += to_copy;
818 if (frag_off == RDS_FRAG_SIZE) {
819 frag = list_entry(frag->f_item.next,
820 struct rds_page_frag, f_item);
821 frag_off = 0;
822 }
823 }
824
825 /* the congestion map is in little endian order */
826 uncongested = le64_to_cpu(uncongested);
827
828 rds_cong_map_updated(map, uncongested);
829}
830
831static void rds_ib_process_recv(struct rds_connection *conn,
832 struct rds_ib_recv_work *recv, u32 data_len,
833 struct rds_ib_ack_state *state)
834{
835 struct rds_ib_connection *ic = conn->c_transport_data;
836 struct rds_ib_incoming *ibinc = ic->i_ibinc;
837 struct rds_header *ihdr, *hdr;
838
839 /* XXX shut down the connection if port 0,0 are seen? */
840
841 rdsdebug("ic %p ibinc %p recv %p byte len %u\n", ic, ibinc, recv,
842 data_len);
843
844 if (data_len < sizeof(struct rds_header)) {
845 rds_ib_conn_error(conn, "incoming message "
846 "from %pI4 didn't include a "
847 "header, disconnecting and "
848 "reconnecting\n",
849 &conn->c_faddr);
850 return;
851 }
852 data_len -= sizeof(struct rds_header);
853
854 ihdr = &ic->i_recv_hdrs[recv - ic->i_recvs];
855
856 /* Validate the checksum. */
857 if (!rds_message_verify_checksum(ihdr)) {
858 rds_ib_conn_error(conn, "incoming message "
859 "from %pI4 has corrupted header - "
860 "forcing a reconnect\n",
861 &conn->c_faddr);
862 rds_stats_inc(s_recv_drop_bad_checksum);
863 return;
864 }
865
866 /* Process the ACK sequence which comes with every packet */
867 state->ack_recv = be64_to_cpu(ihdr->h_ack);
868 state->ack_recv_valid = 1;
869
870 /* Process the credits update if there was one */
871 if (ihdr->h_credit)
872 rds_ib_send_add_credits(conn, ihdr->h_credit);
873
874 if (ihdr->h_sport == 0 && ihdr->h_dport == 0 && data_len == 0) {
875 /* This is an ACK-only packet. The fact that it gets
876 * special treatment here is that historically, ACKs
877 * were rather special beasts.
878 */
879 rds_ib_stats_inc(s_ib_ack_received);
880
881 /*
882 * Usually the frags make their way on to incs and are then freed as
883 * the inc is freed. We don't go that route, so we have to drop the
884 * page ref ourselves. We can't just leave the page on the recv
885 * because that confuses the dma mapping of pages and each recv's use
886 * of a partial page.
887 *
888 * FIXME: Fold this into the code path below.
889 */
890 rds_ib_frag_free(ic, recv->r_frag);
891 recv->r_frag = NULL;
892 return;
893 }
894
895 /*
896 * If we don't already have an inc on the connection then this
897 * fragment has a header and starts a message.. copy its header
898 * into the inc and save the inc so we can hang upcoming fragments
899 * off its list.
900 */
901 if (!ibinc) {
902 ibinc = recv->r_ibinc;
903 recv->r_ibinc = NULL;
904 ic->i_ibinc = ibinc;
905
906 hdr = &ibinc->ii_inc.i_hdr;
907 memcpy(hdr, ihdr, sizeof(*hdr));
908 ic->i_recv_data_rem = be32_to_cpu(hdr->h_len);
909
910 rdsdebug("ic %p ibinc %p rem %u flag 0x%x\n", ic, ibinc,
911 ic->i_recv_data_rem, hdr->h_flags);
912 } else {
913 hdr = &ibinc->ii_inc.i_hdr;
914 /* We can't just use memcmp here; fragments of a
915 * single message may carry different ACKs */
916 if (hdr->h_sequence != ihdr->h_sequence ||
917 hdr->h_len != ihdr->h_len ||
918 hdr->h_sport != ihdr->h_sport ||
919 hdr->h_dport != ihdr->h_dport) {
920 rds_ib_conn_error(conn,
921 "fragment header mismatch; forcing reconnect\n");
922 return;
923 }
924 }
925
926 list_add_tail(&recv->r_frag->f_item, &ibinc->ii_frags);
927 recv->r_frag = NULL;
928
929 if (ic->i_recv_data_rem > RDS_FRAG_SIZE)
930 ic->i_recv_data_rem -= RDS_FRAG_SIZE;
931 else {
932 ic->i_recv_data_rem = 0;
933 ic->i_ibinc = NULL;
934
935 if (ibinc->ii_inc.i_hdr.h_flags == RDS_FLAG_CONG_BITMAP)
936 rds_ib_cong_recv(conn, ibinc);
937 else {
938 rds_recv_incoming(conn, conn->c_faddr, conn->c_laddr,
939 &ibinc->ii_inc, GFP_ATOMIC);
940 state->ack_next = be64_to_cpu(hdr->h_sequence);
941 state->ack_next_valid = 1;
942 }
943
944 /* Evaluate the ACK_REQUIRED flag *after* we received
945 * the complete frame, and after bumping the next_rx
946 * sequence. */
947 if (hdr->h_flags & RDS_FLAG_ACK_REQUIRED) {
948 rds_stats_inc(s_recv_ack_required);
949 state->ack_required = 1;
950 }
951
952 rds_inc_put(&ibinc->ii_inc);
953 }
954}
955
956void rds_ib_recv_cqe_handler(struct rds_ib_connection *ic,
957 struct ib_wc *wc,
958 struct rds_ib_ack_state *state)
959{
960 struct rds_connection *conn = ic->conn;
961 struct rds_ib_recv_work *recv;
962
963 rdsdebug("wc wr_id 0x%llx status %u (%s) byte_len %u imm_data %u\n",
964 (unsigned long long)wc->wr_id, wc->status,
965 ib_wc_status_msg(wc->status), wc->byte_len,
966 be32_to_cpu(wc->ex.imm_data));
967
968 rds_ib_stats_inc(s_ib_rx_cq_event);
969 recv = &ic->i_recvs[rds_ib_ring_oldest(&ic->i_recv_ring)];
970 ib_dma_unmap_sg(ic->i_cm_id->device, &recv->r_frag->f_sg, 1,
971 DMA_FROM_DEVICE);
972
973 /* Also process recvs in connecting state because it is possible
974 * to get a recv completion _before_ the rdmacm ESTABLISHED
975 * event is processed.
976 */
977 if (wc->status == IB_WC_SUCCESS) {
978 rds_ib_process_recv(conn, recv, wc->byte_len, state);
979 } else {
980 /* We expect errors as the qp is drained during shutdown */
981 if (rds_conn_up(conn) || rds_conn_connecting(conn))
982 rds_ib_conn_error(conn, "recv completion on %pI4 had status %u (%s), disconnecting and reconnecting\n",
983 &conn->c_faddr,
984 wc->status,
985 ib_wc_status_msg(wc->status));
986 }
987
988 /* rds_ib_process_recv() doesn't always consume the frag, and
989 * we might not have called it at all if the wc didn't indicate
990 * success. We already unmapped the frag's pages, though, and
991 * the following rds_ib_ring_free() call tells the refill path
992 * that it will not find an allocated frag here. Make sure we
993 * keep that promise by freeing a frag that's still on the ring.
994 */
995 if (recv->r_frag) {
996 rds_ib_frag_free(ic, recv->r_frag);
997 recv->r_frag = NULL;
998 }
999 rds_ib_ring_free(&ic->i_recv_ring, 1);
1000
1001 /* If we ever end up with a really empty receive ring, we're
1002 * in deep trouble, as the sender will definitely see RNR
1003 * timeouts. */
1004 if (rds_ib_ring_empty(&ic->i_recv_ring))
1005 rds_ib_stats_inc(s_ib_rx_ring_empty);
1006
1007 if (rds_ib_ring_low(&ic->i_recv_ring))
1008 rds_ib_recv_refill(conn, 0, GFP_NOWAIT);
1009}
1010
1011int rds_ib_recv(struct rds_connection *conn)
1012{
1013 struct rds_ib_connection *ic = conn->c_transport_data;
1014 int ret = 0;
1015
1016 rdsdebug("conn %p\n", conn);
1017 if (rds_conn_up(conn)) {
1018 rds_ib_attempt_ack(ic);
1019 rds_ib_recv_refill(conn, 0, GFP_KERNEL);
1020 }
1021
1022 return ret;
1023}
1024
1025int rds_ib_recv_init(void)
1026{
1027 struct sysinfo si;
1028 int ret = -ENOMEM;
1029
1030 /* Default to 30% of all available RAM for recv memory */
1031 si_meminfo(&si);
1032 rds_ib_sysctl_max_recv_allocation = si.totalram / 3 * PAGE_SIZE / RDS_FRAG_SIZE;
1033
1034 rds_ib_incoming_slab = kmem_cache_create("rds_ib_incoming",
1035 sizeof(struct rds_ib_incoming),
1036 0, SLAB_HWCACHE_ALIGN, NULL);
1037 if (!rds_ib_incoming_slab)
1038 goto out;
1039
1040 rds_ib_frag_slab = kmem_cache_create("rds_ib_frag",
1041 sizeof(struct rds_page_frag),
1042 0, SLAB_HWCACHE_ALIGN, NULL);
1043 if (!rds_ib_frag_slab) {
1044 kmem_cache_destroy(rds_ib_incoming_slab);
1045 rds_ib_incoming_slab = NULL;
1046 } else
1047 ret = 0;
1048out:
1049 return ret;
1050}
1051
1052void rds_ib_recv_exit(void)
1053{
1054 kmem_cache_destroy(rds_ib_incoming_slab);
1055 kmem_cache_destroy(rds_ib_frag_slab);
1056}
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), KM_SOFTIRQ0);
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, KM_SOFTIRQ0);
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 inclue 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 KM_SOFTIRQ0);
924 state->ack_next = be64_to_cpu(hdr->h_sequence);
925 state->ack_next_valid = 1;
926 }
927
928 /* Evaluate the ACK_REQUIRED flag *after* we received
929 * the complete frame, and after bumping the next_rx
930 * sequence. */
931 if (hdr->h_flags & RDS_FLAG_ACK_REQUIRED) {
932 rds_stats_inc(s_recv_ack_required);
933 state->ack_required = 1;
934 }
935
936 rds_inc_put(&ibinc->ii_inc);
937 }
938}
939
940/*
941 * Plucking the oldest entry from the ring can be done concurrently with
942 * the thread refilling the ring. Each ring operation is protected by
943 * spinlocks and the transient state of refilling doesn't change the
944 * recording of which entry is oldest.
945 *
946 * This relies on IB only calling one cq comp_handler for each cq so that
947 * there will only be one caller of rds_recv_incoming() per RDS connection.
948 */
949void rds_ib_recv_cq_comp_handler(struct ib_cq *cq, void *context)
950{
951 struct rds_connection *conn = context;
952 struct rds_ib_connection *ic = conn->c_transport_data;
953
954 rdsdebug("conn %p cq %p\n", conn, cq);
955
956 rds_ib_stats_inc(s_ib_rx_cq_call);
957
958 tasklet_schedule(&ic->i_recv_tasklet);
959}
960
961static inline void rds_poll_cq(struct rds_ib_connection *ic,
962 struct rds_ib_ack_state *state)
963{
964 struct rds_connection *conn = ic->conn;
965 struct ib_wc wc;
966 struct rds_ib_recv_work *recv;
967
968 while (ib_poll_cq(ic->i_recv_cq, 1, &wc) > 0) {
969 rdsdebug("wc wr_id 0x%llx status %u (%s) byte_len %u imm_data %u\n",
970 (unsigned long long)wc.wr_id, wc.status,
971 rds_ib_wc_status_str(wc.status), wc.byte_len,
972 be32_to_cpu(wc.ex.imm_data));
973 rds_ib_stats_inc(s_ib_rx_cq_event);
974
975 recv = &ic->i_recvs[rds_ib_ring_oldest(&ic->i_recv_ring)];
976
977 ib_dma_unmap_sg(ic->i_cm_id->device, &recv->r_frag->f_sg, 1, DMA_FROM_DEVICE);
978
979 /*
980 * Also process recvs in connecting state because it is possible
981 * to get a recv completion _before_ the rdmacm ESTABLISHED
982 * event is processed.
983 */
984 if (wc.status == IB_WC_SUCCESS) {
985 rds_ib_process_recv(conn, recv, wc.byte_len, state);
986 } else {
987 /* We expect errors as the qp is drained during shutdown */
988 if (rds_conn_up(conn) || rds_conn_connecting(conn))
989 rds_ib_conn_error(conn, "recv completion on %pI4 had "
990 "status %u (%s), disconnecting and "
991 "reconnecting\n", &conn->c_faddr,
992 wc.status,
993 rds_ib_wc_status_str(wc.status));
994 }
995
996 /*
997 * It's very important that we only free this ring entry if we've truly
998 * freed the resources allocated to the entry. The refilling path can
999 * leak if we don't.
1000 */
1001 rds_ib_ring_free(&ic->i_recv_ring, 1);
1002 }
1003}
1004
1005void rds_ib_recv_tasklet_fn(unsigned long data)
1006{
1007 struct rds_ib_connection *ic = (struct rds_ib_connection *) data;
1008 struct rds_connection *conn = ic->conn;
1009 struct rds_ib_ack_state state = { 0, };
1010
1011 rds_poll_cq(ic, &state);
1012 ib_req_notify_cq(ic->i_recv_cq, IB_CQ_SOLICITED);
1013 rds_poll_cq(ic, &state);
1014
1015 if (state.ack_next_valid)
1016 rds_ib_set_ack(ic, state.ack_next, state.ack_required);
1017 if (state.ack_recv_valid && state.ack_recv > ic->i_ack_recv) {
1018 rds_send_drop_acked(conn, state.ack_recv, NULL);
1019 ic->i_ack_recv = state.ack_recv;
1020 }
1021 if (rds_conn_up(conn))
1022 rds_ib_attempt_ack(ic);
1023
1024 /* If we ever end up with a really empty receive ring, we're
1025 * in deep trouble, as the sender will definitely see RNR
1026 * timeouts. */
1027 if (rds_ib_ring_empty(&ic->i_recv_ring))
1028 rds_ib_stats_inc(s_ib_rx_ring_empty);
1029
1030 if (rds_ib_ring_low(&ic->i_recv_ring))
1031 rds_ib_recv_refill(conn, 0);
1032}
1033
1034int rds_ib_recv(struct rds_connection *conn)
1035{
1036 struct rds_ib_connection *ic = conn->c_transport_data;
1037 int ret = 0;
1038
1039 rdsdebug("conn %p\n", conn);
1040 if (rds_conn_up(conn))
1041 rds_ib_attempt_ack(ic);
1042
1043 return ret;
1044}
1045
1046int rds_ib_recv_init(void)
1047{
1048 struct sysinfo si;
1049 int ret = -ENOMEM;
1050
1051 /* Default to 30% of all available RAM for recv memory */
1052 si_meminfo(&si);
1053 rds_ib_sysctl_max_recv_allocation = si.totalram / 3 * PAGE_SIZE / RDS_FRAG_SIZE;
1054
1055 rds_ib_incoming_slab = kmem_cache_create("rds_ib_incoming",
1056 sizeof(struct rds_ib_incoming),
1057 0, SLAB_HWCACHE_ALIGN, NULL);
1058 if (!rds_ib_incoming_slab)
1059 goto out;
1060
1061 rds_ib_frag_slab = kmem_cache_create("rds_ib_frag",
1062 sizeof(struct rds_page_frag),
1063 0, SLAB_HWCACHE_ALIGN, NULL);
1064 if (!rds_ib_frag_slab)
1065 kmem_cache_destroy(rds_ib_incoming_slab);
1066 else
1067 ret = 0;
1068out:
1069 return ret;
1070}
1071
1072void rds_ib_recv_exit(void)
1073{
1074 kmem_cache_destroy(rds_ib_incoming_slab);
1075 kmem_cache_destroy(rds_ib_frag_slab);
1076}