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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_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}
198
199/* Recycle inc after freeing attached frags */
200void rds_ib_inc_free(struct rds_incoming *inc)
201{
202 struct rds_ib_incoming *ibinc;
203 struct rds_page_frag *frag;
204 struct rds_page_frag *pos;
205 struct rds_ib_connection *ic = inc->i_conn->c_transport_data;
206
207 ibinc = container_of(inc, struct rds_ib_incoming, ii_inc);
208
209 /* Free attached frags */
210 list_for_each_entry_safe(frag, pos, &ibinc->ii_frags, f_item) {
211 list_del_init(&frag->f_item);
212 rds_ib_frag_free(ic, frag);
213 }
214 BUG_ON(!list_empty(&ibinc->ii_frags));
215
216 rdsdebug("freeing ibinc %p inc %p\n", ibinc, inc);
217 rds_ib_recv_cache_put(&ibinc->ii_cache_entry, &ic->i_cache_incs);
218}
219
220static void rds_ib_recv_clear_one(struct rds_ib_connection *ic,
221 struct rds_ib_recv_work *recv)
222{
223 if (recv->r_ibinc) {
224 rds_inc_put(&recv->r_ibinc->ii_inc);
225 recv->r_ibinc = NULL;
226 }
227 if (recv->r_frag) {
228 ib_dma_unmap_sg(ic->i_cm_id->device, &recv->r_frag->f_sg, 1, DMA_FROM_DEVICE);
229 rds_ib_frag_free(ic, recv->r_frag);
230 recv->r_frag = NULL;
231 }
232}
233
234void rds_ib_recv_clear_ring(struct rds_ib_connection *ic)
235{
236 u32 i;
237
238 for (i = 0; i < ic->i_recv_ring.w_nr; i++)
239 rds_ib_recv_clear_one(ic, &ic->i_recvs[i]);
240}
241
242static struct rds_ib_incoming *rds_ib_refill_one_inc(struct rds_ib_connection *ic,
243 gfp_t slab_mask)
244{
245 struct rds_ib_incoming *ibinc;
246 struct list_head *cache_item;
247 int avail_allocs;
248
249 cache_item = rds_ib_recv_cache_get(&ic->i_cache_incs);
250 if (cache_item) {
251 ibinc = container_of(cache_item, struct rds_ib_incoming, ii_cache_entry);
252 } else {
253 avail_allocs = atomic_add_unless(&rds_ib_allocation,
254 1, rds_ib_sysctl_max_recv_allocation);
255 if (!avail_allocs) {
256 rds_ib_stats_inc(s_ib_rx_alloc_limit);
257 return NULL;
258 }
259 ibinc = kmem_cache_alloc(rds_ib_incoming_slab, slab_mask);
260 if (!ibinc) {
261 atomic_dec(&rds_ib_allocation);
262 return NULL;
263 }
264 }
265 INIT_LIST_HEAD(&ibinc->ii_frags);
266 rds_inc_init(&ibinc->ii_inc, ic->conn, ic->conn->c_faddr);
267
268 return ibinc;
269}
270
271static struct rds_page_frag *rds_ib_refill_one_frag(struct rds_ib_connection *ic,
272 gfp_t slab_mask, gfp_t page_mask)
273{
274 struct rds_page_frag *frag;
275 struct list_head *cache_item;
276 int ret;
277
278 cache_item = rds_ib_recv_cache_get(&ic->i_cache_frags);
279 if (cache_item) {
280 frag = container_of(cache_item, struct rds_page_frag, f_cache_entry);
281 } else {
282 frag = kmem_cache_alloc(rds_ib_frag_slab, slab_mask);
283 if (!frag)
284 return NULL;
285
286 sg_init_table(&frag->f_sg, 1);
287 ret = rds_page_remainder_alloc(&frag->f_sg,
288 RDS_FRAG_SIZE, page_mask);
289 if (ret) {
290 kmem_cache_free(rds_ib_frag_slab, frag);
291 return NULL;
292 }
293 }
294
295 INIT_LIST_HEAD(&frag->f_item);
296
297 return frag;
298}
299
300static int rds_ib_recv_refill_one(struct rds_connection *conn,
301 struct rds_ib_recv_work *recv, gfp_t gfp)
302{
303 struct rds_ib_connection *ic = conn->c_transport_data;
304 struct ib_sge *sge;
305 int ret = -ENOMEM;
306 gfp_t slab_mask = GFP_NOWAIT;
307 gfp_t page_mask = GFP_NOWAIT;
308
309 if (gfp & __GFP_DIRECT_RECLAIM) {
310 slab_mask = GFP_KERNEL;
311 page_mask = GFP_HIGHUSER;
312 }
313
314 if (!ic->i_cache_incs.ready)
315 rds_ib_cache_xfer_to_ready(&ic->i_cache_incs);
316 if (!ic->i_cache_frags.ready)
317 rds_ib_cache_xfer_to_ready(&ic->i_cache_frags);
318
319 /*
320 * ibinc was taken from recv if recv contained the start of a message.
321 * recvs that were continuations will still have this allocated.
322 */
323 if (!recv->r_ibinc) {
324 recv->r_ibinc = rds_ib_refill_one_inc(ic, slab_mask);
325 if (!recv->r_ibinc)
326 goto out;
327 }
328
329 WARN_ON(recv->r_frag); /* leak! */
330 recv->r_frag = rds_ib_refill_one_frag(ic, slab_mask, page_mask);
331 if (!recv->r_frag)
332 goto out;
333
334 ret = ib_dma_map_sg(ic->i_cm_id->device, &recv->r_frag->f_sg,
335 1, DMA_FROM_DEVICE);
336 WARN_ON(ret != 1);
337
338 sge = &recv->r_sge[0];
339 sge->addr = ic->i_recv_hdrs_dma + (recv - ic->i_recvs) * sizeof(struct rds_header);
340 sge->length = sizeof(struct rds_header);
341
342 sge = &recv->r_sge[1];
343 sge->addr = ib_sg_dma_address(ic->i_cm_id->device, &recv->r_frag->f_sg);
344 sge->length = ib_sg_dma_len(ic->i_cm_id->device, &recv->r_frag->f_sg);
345
346 ret = 0;
347out:
348 return ret;
349}
350
351static int acquire_refill(struct rds_connection *conn)
352{
353 return test_and_set_bit(RDS_RECV_REFILL, &conn->c_flags) == 0;
354}
355
356static void release_refill(struct rds_connection *conn)
357{
358 clear_bit(RDS_RECV_REFILL, &conn->c_flags);
359
360 /* We don't use wait_on_bit()/wake_up_bit() because our waking is in a
361 * hot path and finding waiters is very rare. We don't want to walk
362 * the system-wide hashed waitqueue buckets in the fast path only to
363 * almost never find waiters.
364 */
365 if (waitqueue_active(&conn->c_waitq))
366 wake_up_all(&conn->c_waitq);
367}
368
369/*
370 * This tries to allocate and post unused work requests after making sure that
371 * they have all the allocations they need to queue received fragments into
372 * sockets.
373 *
374 * -1 is returned if posting fails due to temporary resource exhaustion.
375 */
376void rds_ib_recv_refill(struct rds_connection *conn, int prefill, gfp_t gfp)
377{
378 struct rds_ib_connection *ic = conn->c_transport_data;
379 struct rds_ib_recv_work *recv;
380 struct ib_recv_wr *failed_wr;
381 unsigned int posted = 0;
382 int ret = 0;
383 bool can_wait = !!(gfp & __GFP_DIRECT_RECLAIM);
384 u32 pos;
385
386 /* the goal here is to just make sure that someone, somewhere
387 * is posting buffers. If we can't get the refill lock,
388 * let them do their thing
389 */
390 if (!acquire_refill(conn))
391 return;
392
393 while ((prefill || rds_conn_up(conn)) &&
394 rds_ib_ring_alloc(&ic->i_recv_ring, 1, &pos)) {
395 if (pos >= ic->i_recv_ring.w_nr) {
396 printk(KERN_NOTICE "Argh - ring alloc returned pos=%u\n",
397 pos);
398 break;
399 }
400
401 recv = &ic->i_recvs[pos];
402 ret = rds_ib_recv_refill_one(conn, recv, gfp);
403 if (ret) {
404 break;
405 }
406
407 /* XXX when can this fail? */
408 ret = ib_post_recv(ic->i_cm_id->qp, &recv->r_wr, &failed_wr);
409 rdsdebug("recv %p ibinc %p page %p addr %lu ret %d\n", recv,
410 recv->r_ibinc, sg_page(&recv->r_frag->f_sg),
411 (long) ib_sg_dma_address(
412 ic->i_cm_id->device,
413 &recv->r_frag->f_sg),
414 ret);
415 if (ret) {
416 rds_ib_conn_error(conn, "recv post on "
417 "%pI4 returned %d, disconnecting and "
418 "reconnecting\n", &conn->c_faddr,
419 ret);
420 break;
421 }
422
423 posted++;
424 }
425
426 /* We're doing flow control - update the window. */
427 if (ic->i_flowctl && posted)
428 rds_ib_advertise_credits(conn, posted);
429
430 if (ret)
431 rds_ib_ring_unalloc(&ic->i_recv_ring, 1);
432
433 release_refill(conn);
434
435 /* if we're called from the softirq handler, we'll be GFP_NOWAIT.
436 * in this case the ring being low is going to lead to more interrupts
437 * and we can safely let the softirq code take care of it unless the
438 * ring is completely empty.
439 *
440 * if we're called from krdsd, we'll be GFP_KERNEL. In this case
441 * we might have raced with the softirq code while we had the refill
442 * lock held. Use rds_ib_ring_low() instead of ring_empty to decide
443 * if we should requeue.
444 */
445 if (rds_conn_up(conn) &&
446 ((can_wait && rds_ib_ring_low(&ic->i_recv_ring)) ||
447 rds_ib_ring_empty(&ic->i_recv_ring))) {
448 queue_delayed_work(rds_wq, &conn->c_recv_w, 1);
449 }
450}
451
452/*
453 * We want to recycle several types of recv allocations, like incs and frags.
454 * To use this, the *_free() function passes in the ptr to a list_head within
455 * the recyclee, as well as the cache to put it on.
456 *
457 * First, we put the memory on a percpu list. When this reaches a certain size,
458 * We move it to an intermediate non-percpu list in a lockless manner, with some
459 * xchg/compxchg wizardry.
460 *
461 * N.B. Instead of a list_head as the anchor, we use a single pointer, which can
462 * be NULL and xchg'd. The list is actually empty when the pointer is NULL, and
463 * list_empty() will return true with one element is actually present.
464 */
465static void rds_ib_recv_cache_put(struct list_head *new_item,
466 struct rds_ib_refill_cache *cache)
467{
468 unsigned long flags;
469 struct list_head *old, *chpfirst;
470
471 local_irq_save(flags);
472
473 chpfirst = __this_cpu_read(cache->percpu->first);
474 if (!chpfirst)
475 INIT_LIST_HEAD(new_item);
476 else /* put on front */
477 list_add_tail(new_item, chpfirst);
478
479 __this_cpu_write(cache->percpu->first, new_item);
480 __this_cpu_inc(cache->percpu->count);
481
482 if (__this_cpu_read(cache->percpu->count) < RDS_IB_RECYCLE_BATCH_COUNT)
483 goto end;
484
485 /*
486 * Return our per-cpu first list to the cache's xfer by atomically
487 * grabbing the current xfer list, appending it to our per-cpu list,
488 * and then atomically returning that entire list back to the
489 * cache's xfer list as long as it's still empty.
490 */
491 do {
492 old = xchg(&cache->xfer, NULL);
493 if (old)
494 list_splice_entire_tail(old, chpfirst);
495 old = cmpxchg(&cache->xfer, NULL, chpfirst);
496 } while (old);
497
498
499 __this_cpu_write(cache->percpu->first, NULL);
500 __this_cpu_write(cache->percpu->count, 0);
501end:
502 local_irq_restore(flags);
503}
504
505static struct list_head *rds_ib_recv_cache_get(struct rds_ib_refill_cache *cache)
506{
507 struct list_head *head = cache->ready;
508
509 if (head) {
510 if (!list_empty(head)) {
511 cache->ready = head->next;
512 list_del_init(head);
513 } else
514 cache->ready = NULL;
515 }
516
517 return head;
518}
519
520int rds_ib_inc_copy_to_user(struct rds_incoming *inc, struct iov_iter *to)
521{
522 struct rds_ib_incoming *ibinc;
523 struct rds_page_frag *frag;
524 unsigned long to_copy;
525 unsigned long frag_off = 0;
526 int copied = 0;
527 int ret;
528 u32 len;
529
530 ibinc = container_of(inc, struct rds_ib_incoming, ii_inc);
531 frag = list_entry(ibinc->ii_frags.next, struct rds_page_frag, f_item);
532 len = be32_to_cpu(inc->i_hdr.h_len);
533
534 while (iov_iter_count(to) && copied < len) {
535 if (frag_off == RDS_FRAG_SIZE) {
536 frag = list_entry(frag->f_item.next,
537 struct rds_page_frag, f_item);
538 frag_off = 0;
539 }
540 to_copy = min_t(unsigned long, iov_iter_count(to),
541 RDS_FRAG_SIZE - frag_off);
542 to_copy = min_t(unsigned long, to_copy, len - copied);
543
544 /* XXX needs + offset for multiple recvs per page */
545 rds_stats_add(s_copy_to_user, to_copy);
546 ret = copy_page_to_iter(sg_page(&frag->f_sg),
547 frag->f_sg.offset + frag_off,
548 to_copy,
549 to);
550 if (ret != to_copy)
551 return -EFAULT;
552
553 frag_off += to_copy;
554 copied += to_copy;
555 }
556
557 return copied;
558}
559
560/* ic starts out kzalloc()ed */
561void rds_ib_recv_init_ack(struct rds_ib_connection *ic)
562{
563 struct ib_send_wr *wr = &ic->i_ack_wr;
564 struct ib_sge *sge = &ic->i_ack_sge;
565
566 sge->addr = ic->i_ack_dma;
567 sge->length = sizeof(struct rds_header);
568 sge->lkey = ic->i_pd->local_dma_lkey;
569
570 wr->sg_list = sge;
571 wr->num_sge = 1;
572 wr->opcode = IB_WR_SEND;
573 wr->wr_id = RDS_IB_ACK_WR_ID;
574 wr->send_flags = IB_SEND_SIGNALED | IB_SEND_SOLICITED;
575}
576
577/*
578 * You'd think that with reliable IB connections you wouldn't need to ack
579 * messages that have been received. The problem is that IB hardware generates
580 * an ack message before it has DMAed the message into memory. This creates a
581 * potential message loss if the HCA is disabled for any reason between when it
582 * sends the ack and before the message is DMAed and processed. This is only a
583 * potential issue if another HCA is available for fail-over.
584 *
585 * When the remote host receives our ack they'll free the sent message from
586 * their send queue. To decrease the latency of this we always send an ack
587 * immediately after we've received messages.
588 *
589 * For simplicity, we only have one ack in flight at a time. This puts
590 * pressure on senders to have deep enough send queues to absorb the latency of
591 * a single ack frame being in flight. This might not be good enough.
592 *
593 * This is implemented by have a long-lived send_wr and sge which point to a
594 * statically allocated ack frame. This ack wr does not fall under the ring
595 * accounting that the tx and rx wrs do. The QP attribute specifically makes
596 * room for it beyond the ring size. Send completion notices its special
597 * wr_id and avoids working with the ring in that case.
598 */
599#ifndef KERNEL_HAS_ATOMIC64
600void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq, int ack_required)
601{
602 unsigned long flags;
603
604 spin_lock_irqsave(&ic->i_ack_lock, flags);
605 ic->i_ack_next = seq;
606 if (ack_required)
607 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
608 spin_unlock_irqrestore(&ic->i_ack_lock, flags);
609}
610
611static u64 rds_ib_get_ack(struct rds_ib_connection *ic)
612{
613 unsigned long flags;
614 u64 seq;
615
616 clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
617
618 spin_lock_irqsave(&ic->i_ack_lock, flags);
619 seq = ic->i_ack_next;
620 spin_unlock_irqrestore(&ic->i_ack_lock, flags);
621
622 return seq;
623}
624#else
625void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq, int ack_required)
626{
627 atomic64_set(&ic->i_ack_next, seq);
628 if (ack_required) {
629 smp_mb__before_atomic();
630 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
631 }
632}
633
634static u64 rds_ib_get_ack(struct rds_ib_connection *ic)
635{
636 clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
637 smp_mb__after_atomic();
638
639 return atomic64_read(&ic->i_ack_next);
640}
641#endif
642
643
644static void rds_ib_send_ack(struct rds_ib_connection *ic, unsigned int adv_credits)
645{
646 struct rds_header *hdr = ic->i_ack;
647 struct ib_send_wr *failed_wr;
648 u64 seq;
649 int ret;
650
651 seq = rds_ib_get_ack(ic);
652
653 rdsdebug("send_ack: ic %p ack %llu\n", ic, (unsigned long long) seq);
654 rds_message_populate_header(hdr, 0, 0, 0);
655 hdr->h_ack = cpu_to_be64(seq);
656 hdr->h_credit = adv_credits;
657 rds_message_make_checksum(hdr);
658 ic->i_ack_queued = jiffies;
659
660 ret = ib_post_send(ic->i_cm_id->qp, &ic->i_ack_wr, &failed_wr);
661 if (unlikely(ret)) {
662 /* Failed to send. Release the WR, and
663 * force another ACK.
664 */
665 clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
666 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
667
668 rds_ib_stats_inc(s_ib_ack_send_failure);
669
670 rds_ib_conn_error(ic->conn, "sending ack failed\n");
671 } else
672 rds_ib_stats_inc(s_ib_ack_sent);
673}
674
675/*
676 * There are 3 ways of getting acknowledgements to the peer:
677 * 1. We call rds_ib_attempt_ack from the recv completion handler
678 * to send an ACK-only frame.
679 * However, there can be only one such frame in the send queue
680 * at any time, so we may have to postpone it.
681 * 2. When another (data) packet is transmitted while there's
682 * an ACK in the queue, we piggyback the ACK sequence number
683 * on the data packet.
684 * 3. If the ACK WR is done sending, we get called from the
685 * send queue completion handler, and check whether there's
686 * another ACK pending (postponed because the WR was on the
687 * queue). If so, we transmit it.
688 *
689 * We maintain 2 variables:
690 * - i_ack_flags, which keeps track of whether the ACK WR
691 * is currently in the send queue or not (IB_ACK_IN_FLIGHT)
692 * - i_ack_next, which is the last sequence number we received
693 *
694 * Potentially, send queue and receive queue handlers can run concurrently.
695 * It would be nice to not have to use a spinlock to synchronize things,
696 * but the one problem that rules this out is that 64bit updates are
697 * not atomic on all platforms. Things would be a lot simpler if
698 * we had atomic64 or maybe cmpxchg64 everywhere.
699 *
700 * Reconnecting complicates this picture just slightly. When we
701 * reconnect, we may be seeing duplicate packets. The peer
702 * is retransmitting them, because it hasn't seen an ACK for
703 * them. It is important that we ACK these.
704 *
705 * ACK mitigation adds a header flag "ACK_REQUIRED"; any packet with
706 * this flag set *MUST* be acknowledged immediately.
707 */
708
709/*
710 * When we get here, we're called from the recv queue handler.
711 * Check whether we ought to transmit an ACK.
712 */
713void rds_ib_attempt_ack(struct rds_ib_connection *ic)
714{
715 unsigned int adv_credits;
716
717 if (!test_bit(IB_ACK_REQUESTED, &ic->i_ack_flags))
718 return;
719
720 if (test_and_set_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags)) {
721 rds_ib_stats_inc(s_ib_ack_send_delayed);
722 return;
723 }
724
725 /* Can we get a send credit? */
726 if (!rds_ib_send_grab_credits(ic, 1, &adv_credits, 0, RDS_MAX_ADV_CREDIT)) {
727 rds_ib_stats_inc(s_ib_tx_throttle);
728 clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
729 return;
730 }
731
732 clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
733 rds_ib_send_ack(ic, adv_credits);
734}
735
736/*
737 * We get here from the send completion handler, when the
738 * adapter tells us the ACK frame was sent.
739 */
740void rds_ib_ack_send_complete(struct rds_ib_connection *ic)
741{
742 clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
743 rds_ib_attempt_ack(ic);
744}
745
746/*
747 * This is called by the regular xmit code when it wants to piggyback
748 * an ACK on an outgoing frame.
749 */
750u64 rds_ib_piggyb_ack(struct rds_ib_connection *ic)
751{
752 if (test_and_clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags))
753 rds_ib_stats_inc(s_ib_ack_send_piggybacked);
754 return rds_ib_get_ack(ic);
755}
756
757/*
758 * It's kind of lame that we're copying from the posted receive pages into
759 * long-lived bitmaps. We could have posted the bitmaps and rdma written into
760 * them. But receiving new congestion bitmaps should be a *rare* event, so
761 * hopefully we won't need to invest that complexity in making it more
762 * efficient. By copying we can share a simpler core with TCP which has to
763 * copy.
764 */
765static void rds_ib_cong_recv(struct rds_connection *conn,
766 struct rds_ib_incoming *ibinc)
767{
768 struct rds_cong_map *map;
769 unsigned int map_off;
770 unsigned int map_page;
771 struct rds_page_frag *frag;
772 unsigned long frag_off;
773 unsigned long to_copy;
774 unsigned long copied;
775 uint64_t uncongested = 0;
776 void *addr;
777
778 /* catch completely corrupt packets */
779 if (be32_to_cpu(ibinc->ii_inc.i_hdr.h_len) != RDS_CONG_MAP_BYTES)
780 return;
781
782 map = conn->c_fcong;
783 map_page = 0;
784 map_off = 0;
785
786 frag = list_entry(ibinc->ii_frags.next, struct rds_page_frag, f_item);
787 frag_off = 0;
788
789 copied = 0;
790
791 while (copied < RDS_CONG_MAP_BYTES) {
792 uint64_t *src, *dst;
793 unsigned int k;
794
795 to_copy = min(RDS_FRAG_SIZE - frag_off, PAGE_SIZE - map_off);
796 BUG_ON(to_copy & 7); /* Must be 64bit aligned. */
797
798 addr = kmap_atomic(sg_page(&frag->f_sg));
799
800 src = addr + frag->f_sg.offset + frag_off;
801 dst = (void *)map->m_page_addrs[map_page] + map_off;
802 for (k = 0; k < to_copy; k += 8) {
803 /* Record ports that became uncongested, ie
804 * bits that changed from 0 to 1. */
805 uncongested |= ~(*src) & *dst;
806 *dst++ = *src++;
807 }
808 kunmap_atomic(addr);
809
810 copied += to_copy;
811
812 map_off += to_copy;
813 if (map_off == PAGE_SIZE) {
814 map_off = 0;
815 map_page++;
816 }
817
818 frag_off += to_copy;
819 if (frag_off == RDS_FRAG_SIZE) {
820 frag = list_entry(frag->f_item.next,
821 struct rds_page_frag, f_item);
822 frag_off = 0;
823 }
824 }
825
826 /* the congestion map is in little endian order */
827 uncongested = le64_to_cpu(uncongested);
828
829 rds_cong_map_updated(map, uncongested);
830}
831
832static void rds_ib_process_recv(struct rds_connection *conn,
833 struct rds_ib_recv_work *recv, u32 data_len,
834 struct rds_ib_ack_state *state)
835{
836 struct rds_ib_connection *ic = conn->c_transport_data;
837 struct rds_ib_incoming *ibinc = ic->i_ibinc;
838 struct rds_header *ihdr, *hdr;
839
840 /* XXX shut down the connection if port 0,0 are seen? */
841
842 rdsdebug("ic %p ibinc %p recv %p byte len %u\n", ic, ibinc, recv,
843 data_len);
844
845 if (data_len < sizeof(struct rds_header)) {
846 rds_ib_conn_error(conn, "incoming message "
847 "from %pI4 didn't include a "
848 "header, disconnecting and "
849 "reconnecting\n",
850 &conn->c_faddr);
851 return;
852 }
853 data_len -= sizeof(struct rds_header);
854
855 ihdr = &ic->i_recv_hdrs[recv - ic->i_recvs];
856
857 /* Validate the checksum. */
858 if (!rds_message_verify_checksum(ihdr)) {
859 rds_ib_conn_error(conn, "incoming message "
860 "from %pI4 has corrupted header - "
861 "forcing a reconnect\n",
862 &conn->c_faddr);
863 rds_stats_inc(s_recv_drop_bad_checksum);
864 return;
865 }
866
867 /* Process the ACK sequence which comes with every packet */
868 state->ack_recv = be64_to_cpu(ihdr->h_ack);
869 state->ack_recv_valid = 1;
870
871 /* Process the credits update if there was one */
872 if (ihdr->h_credit)
873 rds_ib_send_add_credits(conn, ihdr->h_credit);
874
875 if (ihdr->h_sport == 0 && ihdr->h_dport == 0 && data_len == 0) {
876 /* This is an ACK-only packet. The fact that it gets
877 * special treatment here is that historically, ACKs
878 * were rather special beasts.
879 */
880 rds_ib_stats_inc(s_ib_ack_received);
881
882 /*
883 * Usually the frags make their way on to incs and are then freed as
884 * the inc is freed. We don't go that route, so we have to drop the
885 * page ref ourselves. We can't just leave the page on the recv
886 * because that confuses the dma mapping of pages and each recv's use
887 * of a partial page.
888 *
889 * FIXME: Fold this into the code path below.
890 */
891 rds_ib_frag_free(ic, recv->r_frag);
892 recv->r_frag = NULL;
893 return;
894 }
895
896 /*
897 * If we don't already have an inc on the connection then this
898 * fragment has a header and starts a message.. copy its header
899 * into the inc and save the inc so we can hang upcoming fragments
900 * off its list.
901 */
902 if (!ibinc) {
903 ibinc = recv->r_ibinc;
904 recv->r_ibinc = NULL;
905 ic->i_ibinc = ibinc;
906
907 hdr = &ibinc->ii_inc.i_hdr;
908 memcpy(hdr, ihdr, sizeof(*hdr));
909 ic->i_recv_data_rem = be32_to_cpu(hdr->h_len);
910
911 rdsdebug("ic %p ibinc %p rem %u flag 0x%x\n", ic, ibinc,
912 ic->i_recv_data_rem, hdr->h_flags);
913 } else {
914 hdr = &ibinc->ii_inc.i_hdr;
915 /* We can't just use memcmp here; fragments of a
916 * single message may carry different ACKs */
917 if (hdr->h_sequence != ihdr->h_sequence ||
918 hdr->h_len != ihdr->h_len ||
919 hdr->h_sport != ihdr->h_sport ||
920 hdr->h_dport != ihdr->h_dport) {
921 rds_ib_conn_error(conn,
922 "fragment header mismatch; forcing reconnect\n");
923 return;
924 }
925 }
926
927 list_add_tail(&recv->r_frag->f_item, &ibinc->ii_frags);
928 recv->r_frag = NULL;
929
930 if (ic->i_recv_data_rem > RDS_FRAG_SIZE)
931 ic->i_recv_data_rem -= RDS_FRAG_SIZE;
932 else {
933 ic->i_recv_data_rem = 0;
934 ic->i_ibinc = NULL;
935
936 if (ibinc->ii_inc.i_hdr.h_flags == RDS_FLAG_CONG_BITMAP)
937 rds_ib_cong_recv(conn, ibinc);
938 else {
939 rds_recv_incoming(conn, conn->c_faddr, conn->c_laddr,
940 &ibinc->ii_inc, GFP_ATOMIC);
941 state->ack_next = be64_to_cpu(hdr->h_sequence);
942 state->ack_next_valid = 1;
943 }
944
945 /* Evaluate the ACK_REQUIRED flag *after* we received
946 * the complete frame, and after bumping the next_rx
947 * sequence. */
948 if (hdr->h_flags & RDS_FLAG_ACK_REQUIRED) {
949 rds_stats_inc(s_recv_ack_required);
950 state->ack_required = 1;
951 }
952
953 rds_inc_put(&ibinc->ii_inc);
954 }
955}
956
957void rds_ib_recv_cqe_handler(struct rds_ib_connection *ic,
958 struct ib_wc *wc,
959 struct rds_ib_ack_state *state)
960{
961 struct rds_connection *conn = ic->conn;
962 struct rds_ib_recv_work *recv;
963
964 rdsdebug("wc wr_id 0x%llx status %u (%s) byte_len %u imm_data %u\n",
965 (unsigned long long)wc->wr_id, wc->status,
966 ib_wc_status_msg(wc->status), wc->byte_len,
967 be32_to_cpu(wc->ex.imm_data));
968
969 rds_ib_stats_inc(s_ib_rx_cq_event);
970 recv = &ic->i_recvs[rds_ib_ring_oldest(&ic->i_recv_ring)];
971 ib_dma_unmap_sg(ic->i_cm_id->device, &recv->r_frag->f_sg, 1,
972 DMA_FROM_DEVICE);
973
974 /* Also process recvs in connecting state because it is possible
975 * to get a recv completion _before_ the rdmacm ESTABLISHED
976 * event is processed.
977 */
978 if (wc->status == IB_WC_SUCCESS) {
979 rds_ib_process_recv(conn, recv, wc->byte_len, state);
980 } else {
981 /* We expect errors as the qp is drained during shutdown */
982 if (rds_conn_up(conn) || rds_conn_connecting(conn))
983 rds_ib_conn_error(conn, "recv completion on %pI4 had status %u (%s), disconnecting and reconnecting\n",
984 &conn->c_faddr,
985 wc->status,
986 ib_wc_status_msg(wc->status));
987 }
988
989 /* rds_ib_process_recv() doesn't always consume the frag, and
990 * we might not have called it at all if the wc didn't indicate
991 * success. We already unmapped the frag's pages, though, and
992 * the following rds_ib_ring_free() call tells the refill path
993 * that it will not find an allocated frag here. Make sure we
994 * keep that promise by freeing a frag that's still on the ring.
995 */
996 if (recv->r_frag) {
997 rds_ib_frag_free(ic, recv->r_frag);
998 recv->r_frag = NULL;
999 }
1000 rds_ib_ring_free(&ic->i_recv_ring, 1);
1001
1002 /* If we ever end up with a really empty receive ring, we're
1003 * in deep trouble, as the sender will definitely see RNR
1004 * timeouts. */
1005 if (rds_ib_ring_empty(&ic->i_recv_ring))
1006 rds_ib_stats_inc(s_ib_rx_ring_empty);
1007
1008 if (rds_ib_ring_low(&ic->i_recv_ring))
1009 rds_ib_recv_refill(conn, 0, GFP_NOWAIT);
1010}
1011
1012int rds_ib_recv_path(struct rds_conn_path *cp)
1013{
1014 struct rds_connection *conn = cp->cp_conn;
1015 struct rds_ib_connection *ic = conn->c_transport_data;
1016 int ret = 0;
1017
1018 rdsdebug("conn %p\n", conn);
1019 if (rds_conn_up(conn)) {
1020 rds_ib_attempt_ack(ic);
1021 rds_ib_recv_refill(conn, 0, GFP_KERNEL);
1022 }
1023
1024 return ret;
1025}
1026
1027int rds_ib_recv_init(void)
1028{
1029 struct sysinfo si;
1030 int ret = -ENOMEM;
1031
1032 /* Default to 30% of all available RAM for recv memory */
1033 si_meminfo(&si);
1034 rds_ib_sysctl_max_recv_allocation = si.totalram / 3 * PAGE_SIZE / RDS_FRAG_SIZE;
1035
1036 rds_ib_incoming_slab = kmem_cache_create("rds_ib_incoming",
1037 sizeof(struct rds_ib_incoming),
1038 0, SLAB_HWCACHE_ALIGN, NULL);
1039 if (!rds_ib_incoming_slab)
1040 goto out;
1041
1042 rds_ib_frag_slab = kmem_cache_create("rds_ib_frag",
1043 sizeof(struct rds_page_frag),
1044 0, SLAB_HWCACHE_ALIGN, NULL);
1045 if (!rds_ib_frag_slab) {
1046 kmem_cache_destroy(rds_ib_incoming_slab);
1047 rds_ib_incoming_slab = NULL;
1048 } else
1049 ret = 0;
1050out:
1051 return ret;
1052}
1053
1054void rds_ib_recv_exit(void)
1055{
1056 kmem_cache_destroy(rds_ib_incoming_slab);
1057 kmem_cache_destroy(rds_ib_frag_slab);
1058}
1/*
2 * Copyright (c) 2006, 2019 Oracle and/or its affiliates. All rights reserved.
3 *
4 * This software is available to you under a choice of one of two
5 * licenses. You may choose to be licensed under the terms of the GNU
6 * General Public License (GPL) Version 2, available from the file
7 * COPYING in the main directory of this source tree, or the
8 * OpenIB.org BSD license below:
9 *
10 * Redistribution and use in source and binary forms, with or
11 * without modification, are permitted provided that the following
12 * conditions are met:
13 *
14 * - Redistributions of source code must retain the above
15 * copyright notice, this list of conditions and the following
16 * disclaimer.
17 *
18 * - Redistributions in binary form must reproduce the above
19 * copyright notice, this list of conditions and the following
20 * disclaimer in the documentation and/or other materials
21 * provided with the distribution.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30 * SOFTWARE.
31 *
32 */
33#include <linux/kernel.h>
34#include <linux/sched/clock.h>
35#include <linux/slab.h>
36#include <linux/pci.h>
37#include <linux/dma-mapping.h>
38#include <rdma/rdma_cm.h>
39
40#include "rds_single_path.h"
41#include "rds.h"
42#include "ib.h"
43
44static struct kmem_cache *rds_ib_incoming_slab;
45static struct kmem_cache *rds_ib_frag_slab;
46static atomic_t rds_ib_allocation = ATOMIC_INIT(0);
47
48void rds_ib_recv_init_ring(struct rds_ib_connection *ic)
49{
50 struct rds_ib_recv_work *recv;
51 u32 i;
52
53 for (i = 0, recv = ic->i_recvs; i < ic->i_recv_ring.w_nr; i++, recv++) {
54 struct ib_sge *sge;
55
56 recv->r_ibinc = NULL;
57 recv->r_frag = NULL;
58
59 recv->r_wr.next = NULL;
60 recv->r_wr.wr_id = i;
61 recv->r_wr.sg_list = recv->r_sge;
62 recv->r_wr.num_sge = RDS_IB_RECV_SGE;
63
64 sge = &recv->r_sge[0];
65 sge->addr = ic->i_recv_hdrs_dma[i];
66 sge->length = sizeof(struct rds_header);
67 sge->lkey = ic->i_pd->local_dma_lkey;
68
69 sge = &recv->r_sge[1];
70 sge->addr = 0;
71 sge->length = RDS_FRAG_SIZE;
72 sge->lkey = ic->i_pd->local_dma_lkey;
73 }
74}
75
76/*
77 * The entire 'from' list, including the from element itself, is put on
78 * to the tail of the 'to' list.
79 */
80static void list_splice_entire_tail(struct list_head *from,
81 struct list_head *to)
82{
83 struct list_head *from_last = from->prev;
84
85 list_splice_tail(from_last, to);
86 list_add_tail(from_last, to);
87}
88
89static void rds_ib_cache_xfer_to_ready(struct rds_ib_refill_cache *cache)
90{
91 struct list_head *tmp;
92
93 tmp = xchg(&cache->xfer, NULL);
94 if (tmp) {
95 if (cache->ready)
96 list_splice_entire_tail(tmp, cache->ready);
97 else
98 cache->ready = tmp;
99 }
100}
101
102static int rds_ib_recv_alloc_cache(struct rds_ib_refill_cache *cache, gfp_t gfp)
103{
104 struct rds_ib_cache_head *head;
105 int cpu;
106
107 cache->percpu = alloc_percpu_gfp(struct rds_ib_cache_head, gfp);
108 if (!cache->percpu)
109 return -ENOMEM;
110
111 for_each_possible_cpu(cpu) {
112 head = per_cpu_ptr(cache->percpu, cpu);
113 head->first = NULL;
114 head->count = 0;
115 }
116 cache->xfer = NULL;
117 cache->ready = NULL;
118
119 return 0;
120}
121
122int rds_ib_recv_alloc_caches(struct rds_ib_connection *ic, gfp_t gfp)
123{
124 int ret;
125
126 ret = rds_ib_recv_alloc_cache(&ic->i_cache_incs, gfp);
127 if (!ret) {
128 ret = rds_ib_recv_alloc_cache(&ic->i_cache_frags, gfp);
129 if (ret)
130 free_percpu(ic->i_cache_incs.percpu);
131 }
132
133 return ret;
134}
135
136static void rds_ib_cache_splice_all_lists(struct rds_ib_refill_cache *cache,
137 struct list_head *caller_list)
138{
139 struct rds_ib_cache_head *head;
140 int cpu;
141
142 for_each_possible_cpu(cpu) {
143 head = per_cpu_ptr(cache->percpu, cpu);
144 if (head->first) {
145 list_splice_entire_tail(head->first, caller_list);
146 head->first = NULL;
147 }
148 }
149
150 if (cache->ready) {
151 list_splice_entire_tail(cache->ready, caller_list);
152 cache->ready = NULL;
153 }
154}
155
156void rds_ib_recv_free_caches(struct rds_ib_connection *ic)
157{
158 struct rds_ib_incoming *inc;
159 struct rds_ib_incoming *inc_tmp;
160 struct rds_page_frag *frag;
161 struct rds_page_frag *frag_tmp;
162 LIST_HEAD(list);
163
164 rds_ib_cache_xfer_to_ready(&ic->i_cache_incs);
165 rds_ib_cache_splice_all_lists(&ic->i_cache_incs, &list);
166 free_percpu(ic->i_cache_incs.percpu);
167
168 list_for_each_entry_safe(inc, inc_tmp, &list, ii_cache_entry) {
169 list_del(&inc->ii_cache_entry);
170 WARN_ON(!list_empty(&inc->ii_frags));
171 kmem_cache_free(rds_ib_incoming_slab, inc);
172 atomic_dec(&rds_ib_allocation);
173 }
174
175 rds_ib_cache_xfer_to_ready(&ic->i_cache_frags);
176 rds_ib_cache_splice_all_lists(&ic->i_cache_frags, &list);
177 free_percpu(ic->i_cache_frags.percpu);
178
179 list_for_each_entry_safe(frag, frag_tmp, &list, f_cache_entry) {
180 list_del(&frag->f_cache_entry);
181 WARN_ON(!list_empty(&frag->f_item));
182 kmem_cache_free(rds_ib_frag_slab, frag);
183 }
184}
185
186/* fwd decl */
187static void rds_ib_recv_cache_put(struct list_head *new_item,
188 struct rds_ib_refill_cache *cache);
189static struct list_head *rds_ib_recv_cache_get(struct rds_ib_refill_cache *cache);
190
191
192/* Recycle frag and attached recv buffer f_sg */
193static void rds_ib_frag_free(struct rds_ib_connection *ic,
194 struct rds_page_frag *frag)
195{
196 rdsdebug("frag %p page %p\n", frag, sg_page(&frag->f_sg));
197
198 rds_ib_recv_cache_put(&frag->f_cache_entry, &ic->i_cache_frags);
199 atomic_add(RDS_FRAG_SIZE / SZ_1K, &ic->i_cache_allocs);
200 rds_ib_stats_add(s_ib_recv_added_to_cache, RDS_FRAG_SIZE);
201}
202
203/* Recycle inc after freeing attached frags */
204void rds_ib_inc_free(struct rds_incoming *inc)
205{
206 struct rds_ib_incoming *ibinc;
207 struct rds_page_frag *frag;
208 struct rds_page_frag *pos;
209 struct rds_ib_connection *ic = inc->i_conn->c_transport_data;
210
211 ibinc = container_of(inc, struct rds_ib_incoming, ii_inc);
212
213 /* Free attached frags */
214 list_for_each_entry_safe(frag, pos, &ibinc->ii_frags, f_item) {
215 list_del_init(&frag->f_item);
216 rds_ib_frag_free(ic, frag);
217 }
218 BUG_ON(!list_empty(&ibinc->ii_frags));
219
220 rdsdebug("freeing ibinc %p inc %p\n", ibinc, inc);
221 rds_ib_recv_cache_put(&ibinc->ii_cache_entry, &ic->i_cache_incs);
222}
223
224static void rds_ib_recv_clear_one(struct rds_ib_connection *ic,
225 struct rds_ib_recv_work *recv)
226{
227 if (recv->r_ibinc) {
228 rds_inc_put(&recv->r_ibinc->ii_inc);
229 recv->r_ibinc = NULL;
230 }
231 if (recv->r_frag) {
232 ib_dma_unmap_sg(ic->i_cm_id->device, &recv->r_frag->f_sg, 1, DMA_FROM_DEVICE);
233 rds_ib_frag_free(ic, recv->r_frag);
234 recv->r_frag = NULL;
235 }
236}
237
238void rds_ib_recv_clear_ring(struct rds_ib_connection *ic)
239{
240 u32 i;
241
242 for (i = 0; i < ic->i_recv_ring.w_nr; i++)
243 rds_ib_recv_clear_one(ic, &ic->i_recvs[i]);
244}
245
246static struct rds_ib_incoming *rds_ib_refill_one_inc(struct rds_ib_connection *ic,
247 gfp_t slab_mask)
248{
249 struct rds_ib_incoming *ibinc;
250 struct list_head *cache_item;
251 int avail_allocs;
252
253 cache_item = rds_ib_recv_cache_get(&ic->i_cache_incs);
254 if (cache_item) {
255 ibinc = container_of(cache_item, struct rds_ib_incoming, ii_cache_entry);
256 } else {
257 avail_allocs = atomic_add_unless(&rds_ib_allocation,
258 1, rds_ib_sysctl_max_recv_allocation);
259 if (!avail_allocs) {
260 rds_ib_stats_inc(s_ib_rx_alloc_limit);
261 return NULL;
262 }
263 ibinc = kmem_cache_alloc(rds_ib_incoming_slab, slab_mask);
264 if (!ibinc) {
265 atomic_dec(&rds_ib_allocation);
266 return NULL;
267 }
268 rds_ib_stats_inc(s_ib_rx_total_incs);
269 }
270 INIT_LIST_HEAD(&ibinc->ii_frags);
271 rds_inc_init(&ibinc->ii_inc, ic->conn, &ic->conn->c_faddr);
272
273 return ibinc;
274}
275
276static struct rds_page_frag *rds_ib_refill_one_frag(struct rds_ib_connection *ic,
277 gfp_t slab_mask, gfp_t page_mask)
278{
279 struct rds_page_frag *frag;
280 struct list_head *cache_item;
281 int ret;
282
283 cache_item = rds_ib_recv_cache_get(&ic->i_cache_frags);
284 if (cache_item) {
285 frag = container_of(cache_item, struct rds_page_frag, f_cache_entry);
286 atomic_sub(RDS_FRAG_SIZE / SZ_1K, &ic->i_cache_allocs);
287 rds_ib_stats_add(s_ib_recv_added_to_cache, RDS_FRAG_SIZE);
288 } else {
289 frag = kmem_cache_alloc(rds_ib_frag_slab, slab_mask);
290 if (!frag)
291 return NULL;
292
293 sg_init_table(&frag->f_sg, 1);
294 ret = rds_page_remainder_alloc(&frag->f_sg,
295 RDS_FRAG_SIZE, page_mask);
296 if (ret) {
297 kmem_cache_free(rds_ib_frag_slab, frag);
298 return NULL;
299 }
300 rds_ib_stats_inc(s_ib_rx_total_frags);
301 }
302
303 INIT_LIST_HEAD(&frag->f_item);
304
305 return frag;
306}
307
308static int rds_ib_recv_refill_one(struct rds_connection *conn,
309 struct rds_ib_recv_work *recv, gfp_t gfp)
310{
311 struct rds_ib_connection *ic = conn->c_transport_data;
312 struct ib_sge *sge;
313 int ret = -ENOMEM;
314 gfp_t slab_mask = gfp;
315 gfp_t page_mask = gfp;
316
317 if (gfp & __GFP_DIRECT_RECLAIM) {
318 slab_mask = GFP_KERNEL;
319 page_mask = GFP_HIGHUSER;
320 }
321
322 if (!ic->i_cache_incs.ready)
323 rds_ib_cache_xfer_to_ready(&ic->i_cache_incs);
324 if (!ic->i_cache_frags.ready)
325 rds_ib_cache_xfer_to_ready(&ic->i_cache_frags);
326
327 /*
328 * ibinc was taken from recv if recv contained the start of a message.
329 * recvs that were continuations will still have this allocated.
330 */
331 if (!recv->r_ibinc) {
332 recv->r_ibinc = rds_ib_refill_one_inc(ic, slab_mask);
333 if (!recv->r_ibinc)
334 goto out;
335 }
336
337 WARN_ON(recv->r_frag); /* leak! */
338 recv->r_frag = rds_ib_refill_one_frag(ic, slab_mask, page_mask);
339 if (!recv->r_frag)
340 goto out;
341
342 ret = ib_dma_map_sg(ic->i_cm_id->device, &recv->r_frag->f_sg,
343 1, DMA_FROM_DEVICE);
344 WARN_ON(ret != 1);
345
346 sge = &recv->r_sge[0];
347 sge->addr = ic->i_recv_hdrs_dma[recv - ic->i_recvs];
348 sge->length = sizeof(struct rds_header);
349
350 sge = &recv->r_sge[1];
351 sge->addr = sg_dma_address(&recv->r_frag->f_sg);
352 sge->length = sg_dma_len(&recv->r_frag->f_sg);
353
354 ret = 0;
355out:
356 return ret;
357}
358
359static int acquire_refill(struct rds_connection *conn)
360{
361 return test_and_set_bit(RDS_RECV_REFILL, &conn->c_flags) == 0;
362}
363
364static void release_refill(struct rds_connection *conn)
365{
366 clear_bit(RDS_RECV_REFILL, &conn->c_flags);
367 smp_mb__after_atomic();
368
369 /* We don't use wait_on_bit()/wake_up_bit() because our waking is in a
370 * hot path and finding waiters is very rare. We don't want to walk
371 * the system-wide hashed waitqueue buckets in the fast path only to
372 * almost never find waiters.
373 */
374 if (waitqueue_active(&conn->c_waitq))
375 wake_up_all(&conn->c_waitq);
376}
377
378/*
379 * This tries to allocate and post unused work requests after making sure that
380 * they have all the allocations they need to queue received fragments into
381 * sockets.
382 */
383void rds_ib_recv_refill(struct rds_connection *conn, int prefill, gfp_t gfp)
384{
385 struct rds_ib_connection *ic = conn->c_transport_data;
386 struct rds_ib_recv_work *recv;
387 unsigned int posted = 0;
388 int ret = 0;
389 bool can_wait = !!(gfp & __GFP_DIRECT_RECLAIM);
390 bool must_wake = false;
391 u32 pos;
392
393 /* the goal here is to just make sure that someone, somewhere
394 * is posting buffers. If we can't get the refill lock,
395 * let them do their thing
396 */
397 if (!acquire_refill(conn))
398 return;
399
400 while ((prefill || rds_conn_up(conn)) &&
401 rds_ib_ring_alloc(&ic->i_recv_ring, 1, &pos)) {
402 if (pos >= ic->i_recv_ring.w_nr) {
403 printk(KERN_NOTICE "Argh - ring alloc returned pos=%u\n",
404 pos);
405 break;
406 }
407
408 recv = &ic->i_recvs[pos];
409 ret = rds_ib_recv_refill_one(conn, recv, gfp);
410 if (ret) {
411 must_wake = true;
412 break;
413 }
414
415 rdsdebug("recv %p ibinc %p page %p addr %lu\n", recv,
416 recv->r_ibinc, sg_page(&recv->r_frag->f_sg),
417 (long)sg_dma_address(&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, NULL);
421 if (ret) {
422 rds_ib_conn_error(conn, "recv post on "
423 "%pI6c returned %d, disconnecting and "
424 "reconnecting\n", &conn->c_faddr,
425 ret);
426 break;
427 }
428
429 posted++;
430
431 if ((posted > 128 && need_resched()) || posted > 8192) {
432 must_wake = true;
433 break;
434 }
435 }
436
437 /* We're doing flow control - update the window. */
438 if (ic->i_flowctl && posted)
439 rds_ib_advertise_credits(conn, posted);
440
441 if (ret)
442 rds_ib_ring_unalloc(&ic->i_recv_ring, 1);
443
444 release_refill(conn);
445
446 /* if we're called from the softirq handler, we'll be GFP_NOWAIT.
447 * in this case the ring being low is going to lead to more interrupts
448 * and we can safely let the softirq code take care of it unless the
449 * ring is completely empty.
450 *
451 * if we're called from krdsd, we'll be GFP_KERNEL. In this case
452 * we might have raced with the softirq code while we had the refill
453 * lock held. Use rds_ib_ring_low() instead of ring_empty to decide
454 * if we should requeue.
455 */
456 if (rds_conn_up(conn) &&
457 (must_wake ||
458 (can_wait && rds_ib_ring_low(&ic->i_recv_ring)) ||
459 rds_ib_ring_empty(&ic->i_recv_ring))) {
460 queue_delayed_work(rds_wq, &conn->c_recv_w, 1);
461 }
462 if (can_wait)
463 cond_resched();
464}
465
466/*
467 * We want to recycle several types of recv allocations, like incs and frags.
468 * To use this, the *_free() function passes in the ptr to a list_head within
469 * the recyclee, as well as the cache to put it on.
470 *
471 * First, we put the memory on a percpu list. When this reaches a certain size,
472 * We move it to an intermediate non-percpu list in a lockless manner, with some
473 * xchg/compxchg wizardry.
474 *
475 * N.B. Instead of a list_head as the anchor, we use a single pointer, which can
476 * be NULL and xchg'd. The list is actually empty when the pointer is NULL, and
477 * list_empty() will return true with one element is actually present.
478 */
479static void rds_ib_recv_cache_put(struct list_head *new_item,
480 struct rds_ib_refill_cache *cache)
481{
482 unsigned long flags;
483 struct list_head *old, *chpfirst;
484
485 local_irq_save(flags);
486
487 chpfirst = __this_cpu_read(cache->percpu->first);
488 if (!chpfirst)
489 INIT_LIST_HEAD(new_item);
490 else /* put on front */
491 list_add_tail(new_item, chpfirst);
492
493 __this_cpu_write(cache->percpu->first, new_item);
494 __this_cpu_inc(cache->percpu->count);
495
496 if (__this_cpu_read(cache->percpu->count) < RDS_IB_RECYCLE_BATCH_COUNT)
497 goto end;
498
499 /*
500 * Return our per-cpu first list to the cache's xfer by atomically
501 * grabbing the current xfer list, appending it to our per-cpu list,
502 * and then atomically returning that entire list back to the
503 * cache's xfer list as long as it's still empty.
504 */
505 do {
506 old = xchg(&cache->xfer, NULL);
507 if (old)
508 list_splice_entire_tail(old, chpfirst);
509 old = cmpxchg(&cache->xfer, NULL, chpfirst);
510 } while (old);
511
512
513 __this_cpu_write(cache->percpu->first, NULL);
514 __this_cpu_write(cache->percpu->count, 0);
515end:
516 local_irq_restore(flags);
517}
518
519static struct list_head *rds_ib_recv_cache_get(struct rds_ib_refill_cache *cache)
520{
521 struct list_head *head = cache->ready;
522
523 if (head) {
524 if (!list_empty(head)) {
525 cache->ready = head->next;
526 list_del_init(head);
527 } else
528 cache->ready = NULL;
529 }
530
531 return head;
532}
533
534int rds_ib_inc_copy_to_user(struct rds_incoming *inc, struct iov_iter *to)
535{
536 struct rds_ib_incoming *ibinc;
537 struct rds_page_frag *frag;
538 unsigned long to_copy;
539 unsigned long frag_off = 0;
540 int copied = 0;
541 int ret;
542 u32 len;
543
544 ibinc = container_of(inc, struct rds_ib_incoming, ii_inc);
545 frag = list_entry(ibinc->ii_frags.next, struct rds_page_frag, f_item);
546 len = be32_to_cpu(inc->i_hdr.h_len);
547
548 while (iov_iter_count(to) && copied < len) {
549 if (frag_off == RDS_FRAG_SIZE) {
550 frag = list_entry(frag->f_item.next,
551 struct rds_page_frag, f_item);
552 frag_off = 0;
553 }
554 to_copy = min_t(unsigned long, iov_iter_count(to),
555 RDS_FRAG_SIZE - frag_off);
556 to_copy = min_t(unsigned long, to_copy, len - copied);
557
558 /* XXX needs + offset for multiple recvs per page */
559 rds_stats_add(s_copy_to_user, to_copy);
560 ret = copy_page_to_iter(sg_page(&frag->f_sg),
561 frag->f_sg.offset + frag_off,
562 to_copy,
563 to);
564 if (ret != to_copy)
565 return -EFAULT;
566
567 frag_off += to_copy;
568 copied += to_copy;
569 }
570
571 return copied;
572}
573
574/* ic starts out kzalloc()ed */
575void rds_ib_recv_init_ack(struct rds_ib_connection *ic)
576{
577 struct ib_send_wr *wr = &ic->i_ack_wr;
578 struct ib_sge *sge = &ic->i_ack_sge;
579
580 sge->addr = ic->i_ack_dma;
581 sge->length = sizeof(struct rds_header);
582 sge->lkey = ic->i_pd->local_dma_lkey;
583
584 wr->sg_list = sge;
585 wr->num_sge = 1;
586 wr->opcode = IB_WR_SEND;
587 wr->wr_id = RDS_IB_ACK_WR_ID;
588 wr->send_flags = IB_SEND_SIGNALED | IB_SEND_SOLICITED;
589}
590
591/*
592 * You'd think that with reliable IB connections you wouldn't need to ack
593 * messages that have been received. The problem is that IB hardware generates
594 * an ack message before it has DMAed the message into memory. This creates a
595 * potential message loss if the HCA is disabled for any reason between when it
596 * sends the ack and before the message is DMAed and processed. This is only a
597 * potential issue if another HCA is available for fail-over.
598 *
599 * When the remote host receives our ack they'll free the sent message from
600 * their send queue. To decrease the latency of this we always send an ack
601 * immediately after we've received messages.
602 *
603 * For simplicity, we only have one ack in flight at a time. This puts
604 * pressure on senders to have deep enough send queues to absorb the latency of
605 * a single ack frame being in flight. This might not be good enough.
606 *
607 * This is implemented by have a long-lived send_wr and sge which point to a
608 * statically allocated ack frame. This ack wr does not fall under the ring
609 * accounting that the tx and rx wrs do. The QP attribute specifically makes
610 * room for it beyond the ring size. Send completion notices its special
611 * wr_id and avoids working with the ring in that case.
612 */
613#ifndef KERNEL_HAS_ATOMIC64
614void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq, int ack_required)
615{
616 unsigned long flags;
617
618 spin_lock_irqsave(&ic->i_ack_lock, flags);
619 ic->i_ack_next = seq;
620 if (ack_required)
621 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
622 spin_unlock_irqrestore(&ic->i_ack_lock, flags);
623}
624
625static u64 rds_ib_get_ack(struct rds_ib_connection *ic)
626{
627 unsigned long flags;
628 u64 seq;
629
630 clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
631
632 spin_lock_irqsave(&ic->i_ack_lock, flags);
633 seq = ic->i_ack_next;
634 spin_unlock_irqrestore(&ic->i_ack_lock, flags);
635
636 return seq;
637}
638#else
639void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq, int ack_required)
640{
641 atomic64_set(&ic->i_ack_next, seq);
642 if (ack_required) {
643 smp_mb__before_atomic();
644 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
645 }
646}
647
648static u64 rds_ib_get_ack(struct rds_ib_connection *ic)
649{
650 clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
651 smp_mb__after_atomic();
652
653 return atomic64_read(&ic->i_ack_next);
654}
655#endif
656
657
658static void rds_ib_send_ack(struct rds_ib_connection *ic, unsigned int adv_credits)
659{
660 struct rds_header *hdr = ic->i_ack;
661 u64 seq;
662 int ret;
663
664 seq = rds_ib_get_ack(ic);
665
666 rdsdebug("send_ack: ic %p ack %llu\n", ic, (unsigned long long) seq);
667
668 ib_dma_sync_single_for_cpu(ic->rds_ibdev->dev, ic->i_ack_dma,
669 sizeof(*hdr), DMA_TO_DEVICE);
670 rds_message_populate_header(hdr, 0, 0, 0);
671 hdr->h_ack = cpu_to_be64(seq);
672 hdr->h_credit = adv_credits;
673 rds_message_make_checksum(hdr);
674 ib_dma_sync_single_for_device(ic->rds_ibdev->dev, ic->i_ack_dma,
675 sizeof(*hdr), DMA_TO_DEVICE);
676
677 ic->i_ack_queued = jiffies;
678
679 ret = ib_post_send(ic->i_cm_id->qp, &ic->i_ack_wr, NULL);
680 if (unlikely(ret)) {
681 /* Failed to send. Release the WR, and
682 * force another ACK.
683 */
684 clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
685 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
686
687 rds_ib_stats_inc(s_ib_ack_send_failure);
688
689 rds_ib_conn_error(ic->conn, "sending ack failed\n");
690 } else
691 rds_ib_stats_inc(s_ib_ack_sent);
692}
693
694/*
695 * There are 3 ways of getting acknowledgements to the peer:
696 * 1. We call rds_ib_attempt_ack from the recv completion handler
697 * to send an ACK-only frame.
698 * However, there can be only one such frame in the send queue
699 * at any time, so we may have to postpone it.
700 * 2. When another (data) packet is transmitted while there's
701 * an ACK in the queue, we piggyback the ACK sequence number
702 * on the data packet.
703 * 3. If the ACK WR is done sending, we get called from the
704 * send queue completion handler, and check whether there's
705 * another ACK pending (postponed because the WR was on the
706 * queue). If so, we transmit it.
707 *
708 * We maintain 2 variables:
709 * - i_ack_flags, which keeps track of whether the ACK WR
710 * is currently in the send queue or not (IB_ACK_IN_FLIGHT)
711 * - i_ack_next, which is the last sequence number we received
712 *
713 * Potentially, send queue and receive queue handlers can run concurrently.
714 * It would be nice to not have to use a spinlock to synchronize things,
715 * but the one problem that rules this out is that 64bit updates are
716 * not atomic on all platforms. Things would be a lot simpler if
717 * we had atomic64 or maybe cmpxchg64 everywhere.
718 *
719 * Reconnecting complicates this picture just slightly. When we
720 * reconnect, we may be seeing duplicate packets. The peer
721 * is retransmitting them, because it hasn't seen an ACK for
722 * them. It is important that we ACK these.
723 *
724 * ACK mitigation adds a header flag "ACK_REQUIRED"; any packet with
725 * this flag set *MUST* be acknowledged immediately.
726 */
727
728/*
729 * When we get here, we're called from the recv queue handler.
730 * Check whether we ought to transmit an ACK.
731 */
732void rds_ib_attempt_ack(struct rds_ib_connection *ic)
733{
734 unsigned int adv_credits;
735
736 if (!test_bit(IB_ACK_REQUESTED, &ic->i_ack_flags))
737 return;
738
739 if (test_and_set_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags)) {
740 rds_ib_stats_inc(s_ib_ack_send_delayed);
741 return;
742 }
743
744 /* Can we get a send credit? */
745 if (!rds_ib_send_grab_credits(ic, 1, &adv_credits, 0, RDS_MAX_ADV_CREDIT)) {
746 rds_ib_stats_inc(s_ib_tx_throttle);
747 clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
748 return;
749 }
750
751 clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
752 rds_ib_send_ack(ic, adv_credits);
753}
754
755/*
756 * We get here from the send completion handler, when the
757 * adapter tells us the ACK frame was sent.
758 */
759void rds_ib_ack_send_complete(struct rds_ib_connection *ic)
760{
761 clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
762 rds_ib_attempt_ack(ic);
763}
764
765/*
766 * This is called by the regular xmit code when it wants to piggyback
767 * an ACK on an outgoing frame.
768 */
769u64 rds_ib_piggyb_ack(struct rds_ib_connection *ic)
770{
771 if (test_and_clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags))
772 rds_ib_stats_inc(s_ib_ack_send_piggybacked);
773 return rds_ib_get_ack(ic);
774}
775
776/*
777 * It's kind of lame that we're copying from the posted receive pages into
778 * long-lived bitmaps. We could have posted the bitmaps and rdma written into
779 * them. But receiving new congestion bitmaps should be a *rare* event, so
780 * hopefully we won't need to invest that complexity in making it more
781 * efficient. By copying we can share a simpler core with TCP which has to
782 * copy.
783 */
784static void rds_ib_cong_recv(struct rds_connection *conn,
785 struct rds_ib_incoming *ibinc)
786{
787 struct rds_cong_map *map;
788 unsigned int map_off;
789 unsigned int map_page;
790 struct rds_page_frag *frag;
791 unsigned long frag_off;
792 unsigned long to_copy;
793 unsigned long copied;
794 __le64 uncongested = 0;
795 void *addr;
796
797 /* catch completely corrupt packets */
798 if (be32_to_cpu(ibinc->ii_inc.i_hdr.h_len) != RDS_CONG_MAP_BYTES)
799 return;
800
801 map = conn->c_fcong;
802 map_page = 0;
803 map_off = 0;
804
805 frag = list_entry(ibinc->ii_frags.next, struct rds_page_frag, f_item);
806 frag_off = 0;
807
808 copied = 0;
809
810 while (copied < RDS_CONG_MAP_BYTES) {
811 __le64 *src, *dst;
812 unsigned int k;
813
814 to_copy = min(RDS_FRAG_SIZE - frag_off, PAGE_SIZE - map_off);
815 BUG_ON(to_copy & 7); /* Must be 64bit aligned. */
816
817 addr = kmap_atomic(sg_page(&frag->f_sg));
818
819 src = addr + frag->f_sg.offset + frag_off;
820 dst = (void *)map->m_page_addrs[map_page] + map_off;
821 for (k = 0; k < to_copy; k += 8) {
822 /* Record ports that became uncongested, ie
823 * bits that changed from 0 to 1. */
824 uncongested |= ~(*src) & *dst;
825 *dst++ = *src++;
826 }
827 kunmap_atomic(addr);
828
829 copied += to_copy;
830
831 map_off += to_copy;
832 if (map_off == PAGE_SIZE) {
833 map_off = 0;
834 map_page++;
835 }
836
837 frag_off += to_copy;
838 if (frag_off == RDS_FRAG_SIZE) {
839 frag = list_entry(frag->f_item.next,
840 struct rds_page_frag, f_item);
841 frag_off = 0;
842 }
843 }
844
845 /* the congestion map is in little endian order */
846 rds_cong_map_updated(map, le64_to_cpu(uncongested));
847}
848
849static void rds_ib_process_recv(struct rds_connection *conn,
850 struct rds_ib_recv_work *recv, u32 data_len,
851 struct rds_ib_ack_state *state)
852{
853 struct rds_ib_connection *ic = conn->c_transport_data;
854 struct rds_ib_incoming *ibinc = ic->i_ibinc;
855 struct rds_header *ihdr, *hdr;
856 dma_addr_t dma_addr = ic->i_recv_hdrs_dma[recv - ic->i_recvs];
857
858 /* XXX shut down the connection if port 0,0 are seen? */
859
860 rdsdebug("ic %p ibinc %p recv %p byte len %u\n", ic, ibinc, recv,
861 data_len);
862
863 if (data_len < sizeof(struct rds_header)) {
864 rds_ib_conn_error(conn, "incoming message "
865 "from %pI6c didn't include a "
866 "header, disconnecting and "
867 "reconnecting\n",
868 &conn->c_faddr);
869 return;
870 }
871 data_len -= sizeof(struct rds_header);
872
873 ihdr = ic->i_recv_hdrs[recv - ic->i_recvs];
874
875 ib_dma_sync_single_for_cpu(ic->rds_ibdev->dev, dma_addr,
876 sizeof(*ihdr), DMA_FROM_DEVICE);
877 /* Validate the checksum. */
878 if (!rds_message_verify_checksum(ihdr)) {
879 rds_ib_conn_error(conn, "incoming message "
880 "from %pI6c has corrupted header - "
881 "forcing a reconnect\n",
882 &conn->c_faddr);
883 rds_stats_inc(s_recv_drop_bad_checksum);
884 goto done;
885 }
886
887 /* Process the ACK sequence which comes with every packet */
888 state->ack_recv = be64_to_cpu(ihdr->h_ack);
889 state->ack_recv_valid = 1;
890
891 /* Process the credits update if there was one */
892 if (ihdr->h_credit)
893 rds_ib_send_add_credits(conn, ihdr->h_credit);
894
895 if (ihdr->h_sport == 0 && ihdr->h_dport == 0 && data_len == 0) {
896 /* This is an ACK-only packet. The fact that it gets
897 * special treatment here is that historically, ACKs
898 * were rather special beasts.
899 */
900 rds_ib_stats_inc(s_ib_ack_received);
901
902 /*
903 * Usually the frags make their way on to incs and are then freed as
904 * the inc is freed. We don't go that route, so we have to drop the
905 * page ref ourselves. We can't just leave the page on the recv
906 * because that confuses the dma mapping of pages and each recv's use
907 * of a partial page.
908 *
909 * FIXME: Fold this into the code path below.
910 */
911 rds_ib_frag_free(ic, recv->r_frag);
912 recv->r_frag = NULL;
913 goto done;
914 }
915
916 /*
917 * If we don't already have an inc on the connection then this
918 * fragment has a header and starts a message.. copy its header
919 * into the inc and save the inc so we can hang upcoming fragments
920 * off its list.
921 */
922 if (!ibinc) {
923 ibinc = recv->r_ibinc;
924 recv->r_ibinc = NULL;
925 ic->i_ibinc = ibinc;
926
927 hdr = &ibinc->ii_inc.i_hdr;
928 ibinc->ii_inc.i_rx_lat_trace[RDS_MSG_RX_HDR] =
929 local_clock();
930 memcpy(hdr, ihdr, sizeof(*hdr));
931 ic->i_recv_data_rem = be32_to_cpu(hdr->h_len);
932 ibinc->ii_inc.i_rx_lat_trace[RDS_MSG_RX_START] =
933 local_clock();
934
935 rdsdebug("ic %p ibinc %p rem %u flag 0x%x\n", ic, ibinc,
936 ic->i_recv_data_rem, hdr->h_flags);
937 } else {
938 hdr = &ibinc->ii_inc.i_hdr;
939 /* We can't just use memcmp here; fragments of a
940 * single message may carry different ACKs */
941 if (hdr->h_sequence != ihdr->h_sequence ||
942 hdr->h_len != ihdr->h_len ||
943 hdr->h_sport != ihdr->h_sport ||
944 hdr->h_dport != ihdr->h_dport) {
945 rds_ib_conn_error(conn,
946 "fragment header mismatch; forcing reconnect\n");
947 goto done;
948 }
949 }
950
951 list_add_tail(&recv->r_frag->f_item, &ibinc->ii_frags);
952 recv->r_frag = NULL;
953
954 if (ic->i_recv_data_rem > RDS_FRAG_SIZE)
955 ic->i_recv_data_rem -= RDS_FRAG_SIZE;
956 else {
957 ic->i_recv_data_rem = 0;
958 ic->i_ibinc = NULL;
959
960 if (ibinc->ii_inc.i_hdr.h_flags == RDS_FLAG_CONG_BITMAP) {
961 rds_ib_cong_recv(conn, ibinc);
962 } else {
963 rds_recv_incoming(conn, &conn->c_faddr, &conn->c_laddr,
964 &ibinc->ii_inc, GFP_ATOMIC);
965 state->ack_next = be64_to_cpu(hdr->h_sequence);
966 state->ack_next_valid = 1;
967 }
968
969 /* Evaluate the ACK_REQUIRED flag *after* we received
970 * the complete frame, and after bumping the next_rx
971 * sequence. */
972 if (hdr->h_flags & RDS_FLAG_ACK_REQUIRED) {
973 rds_stats_inc(s_recv_ack_required);
974 state->ack_required = 1;
975 }
976
977 rds_inc_put(&ibinc->ii_inc);
978 }
979done:
980 ib_dma_sync_single_for_device(ic->rds_ibdev->dev, dma_addr,
981 sizeof(*ihdr), DMA_FROM_DEVICE);
982}
983
984void rds_ib_recv_cqe_handler(struct rds_ib_connection *ic,
985 struct ib_wc *wc,
986 struct rds_ib_ack_state *state)
987{
988 struct rds_connection *conn = ic->conn;
989 struct rds_ib_recv_work *recv;
990
991 rdsdebug("wc wr_id 0x%llx status %u (%s) byte_len %u imm_data %u\n",
992 (unsigned long long)wc->wr_id, wc->status,
993 ib_wc_status_msg(wc->status), wc->byte_len,
994 be32_to_cpu(wc->ex.imm_data));
995
996 rds_ib_stats_inc(s_ib_rx_cq_event);
997 recv = &ic->i_recvs[rds_ib_ring_oldest(&ic->i_recv_ring)];
998 ib_dma_unmap_sg(ic->i_cm_id->device, &recv->r_frag->f_sg, 1,
999 DMA_FROM_DEVICE);
1000
1001 /* Also process recvs in connecting state because it is possible
1002 * to get a recv completion _before_ the rdmacm ESTABLISHED
1003 * event is processed.
1004 */
1005 if (wc->status == IB_WC_SUCCESS) {
1006 rds_ib_process_recv(conn, recv, wc->byte_len, state);
1007 } else {
1008 /* We expect errors as the qp is drained during shutdown */
1009 if (rds_conn_up(conn) || rds_conn_connecting(conn))
1010 rds_ib_conn_error(conn, "recv completion on <%pI6c,%pI6c, %d> had status %u (%s), vendor err 0x%x, disconnecting and reconnecting\n",
1011 &conn->c_laddr, &conn->c_faddr,
1012 conn->c_tos, wc->status,
1013 ib_wc_status_msg(wc->status),
1014 wc->vendor_err);
1015 }
1016
1017 /* rds_ib_process_recv() doesn't always consume the frag, and
1018 * we might not have called it at all if the wc didn't indicate
1019 * success. We already unmapped the frag's pages, though, and
1020 * the following rds_ib_ring_free() call tells the refill path
1021 * that it will not find an allocated frag here. Make sure we
1022 * keep that promise by freeing a frag that's still on the ring.
1023 */
1024 if (recv->r_frag) {
1025 rds_ib_frag_free(ic, recv->r_frag);
1026 recv->r_frag = NULL;
1027 }
1028 rds_ib_ring_free(&ic->i_recv_ring, 1);
1029
1030 /* If we ever end up with a really empty receive ring, we're
1031 * in deep trouble, as the sender will definitely see RNR
1032 * timeouts. */
1033 if (rds_ib_ring_empty(&ic->i_recv_ring))
1034 rds_ib_stats_inc(s_ib_rx_ring_empty);
1035
1036 if (rds_ib_ring_low(&ic->i_recv_ring)) {
1037 rds_ib_recv_refill(conn, 0, GFP_NOWAIT | __GFP_NOWARN);
1038 rds_ib_stats_inc(s_ib_rx_refill_from_cq);
1039 }
1040}
1041
1042int rds_ib_recv_path(struct rds_conn_path *cp)
1043{
1044 struct rds_connection *conn = cp->cp_conn;
1045 struct rds_ib_connection *ic = conn->c_transport_data;
1046
1047 rdsdebug("conn %p\n", conn);
1048 if (rds_conn_up(conn)) {
1049 rds_ib_attempt_ack(ic);
1050 rds_ib_recv_refill(conn, 0, GFP_KERNEL);
1051 rds_ib_stats_inc(s_ib_rx_refill_from_thread);
1052 }
1053
1054 return 0;
1055}
1056
1057int rds_ib_recv_init(void)
1058{
1059 struct sysinfo si;
1060 int ret = -ENOMEM;
1061
1062 /* Default to 30% of all available RAM for recv memory */
1063 si_meminfo(&si);
1064 rds_ib_sysctl_max_recv_allocation = si.totalram / 3 * PAGE_SIZE / RDS_FRAG_SIZE;
1065
1066 rds_ib_incoming_slab =
1067 kmem_cache_create_usercopy("rds_ib_incoming",
1068 sizeof(struct rds_ib_incoming),
1069 0, SLAB_HWCACHE_ALIGN,
1070 offsetof(struct rds_ib_incoming,
1071 ii_inc.i_usercopy),
1072 sizeof(struct rds_inc_usercopy),
1073 NULL);
1074 if (!rds_ib_incoming_slab)
1075 goto out;
1076
1077 rds_ib_frag_slab = kmem_cache_create("rds_ib_frag",
1078 sizeof(struct rds_page_frag),
1079 0, SLAB_HWCACHE_ALIGN, NULL);
1080 if (!rds_ib_frag_slab) {
1081 kmem_cache_destroy(rds_ib_incoming_slab);
1082 rds_ib_incoming_slab = NULL;
1083 } else
1084 ret = 0;
1085out:
1086 return ret;
1087}
1088
1089void rds_ib_recv_exit(void)
1090{
1091 WARN_ON(atomic_read(&rds_ib_allocation));
1092
1093 kmem_cache_destroy(rds_ib_incoming_slab);
1094 kmem_cache_destroy(rds_ib_frag_slab);
1095}