blob: 2f009d391c293c4ae59fcf44bf6bbe8476b1e43d [file] [log] [blame]
Andy Grover1e23b3e2009-02-24 15:30:34 +00001/*
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/pci.h>
35#include <linux/dma-mapping.h>
36#include <rdma/rdma_cm.h>
37
38#include "rds.h"
39#include "ib.h"
40
41static struct kmem_cache *rds_ib_incoming_slab;
42static struct kmem_cache *rds_ib_frag_slab;
43static atomic_t rds_ib_allocation = ATOMIC_INIT(0);
44
45static void rds_ib_frag_drop_page(struct rds_page_frag *frag)
46{
47 rdsdebug("frag %p page %p\n", frag, frag->f_page);
48 __free_page(frag->f_page);
49 frag->f_page = NULL;
50}
51
52static void rds_ib_frag_free(struct rds_page_frag *frag)
53{
54 rdsdebug("frag %p page %p\n", frag, frag->f_page);
55 BUG_ON(frag->f_page != NULL);
56 kmem_cache_free(rds_ib_frag_slab, frag);
57}
58
59/*
60 * We map a page at a time. Its fragments are posted in order. This
61 * is called in fragment order as the fragments get send completion events.
62 * Only the last frag in the page performs the unmapping.
63 *
64 * It's OK for ring cleanup to call this in whatever order it likes because
65 * DMA is not in flight and so we can unmap while other ring entries still
66 * hold page references in their frags.
67 */
68static void rds_ib_recv_unmap_page(struct rds_ib_connection *ic,
69 struct rds_ib_recv_work *recv)
70{
71 struct rds_page_frag *frag = recv->r_frag;
72
73 rdsdebug("recv %p frag %p page %p\n", recv, frag, frag->f_page);
74 if (frag->f_mapped)
75 ib_dma_unmap_page(ic->i_cm_id->device,
76 frag->f_mapped,
77 RDS_FRAG_SIZE, DMA_FROM_DEVICE);
78 frag->f_mapped = 0;
79}
80
81void rds_ib_recv_init_ring(struct rds_ib_connection *ic)
82{
83 struct rds_ib_recv_work *recv;
84 u32 i;
85
86 for (i = 0, recv = ic->i_recvs; i < ic->i_recv_ring.w_nr; i++, recv++) {
87 struct ib_sge *sge;
88
89 recv->r_ibinc = NULL;
90 recv->r_frag = NULL;
91
92 recv->r_wr.next = NULL;
93 recv->r_wr.wr_id = i;
94 recv->r_wr.sg_list = recv->r_sge;
95 recv->r_wr.num_sge = RDS_IB_RECV_SGE;
96
97 sge = rds_ib_data_sge(ic, recv->r_sge);
98 sge->addr = 0;
99 sge->length = RDS_FRAG_SIZE;
100 sge->lkey = ic->i_mr->lkey;
101
102 sge = rds_ib_header_sge(ic, recv->r_sge);
103 sge->addr = ic->i_recv_hdrs_dma + (i * sizeof(struct rds_header));
104 sge->length = sizeof(struct rds_header);
105 sge->lkey = ic->i_mr->lkey;
106 }
107}
108
109static void rds_ib_recv_clear_one(struct rds_ib_connection *ic,
110 struct rds_ib_recv_work *recv)
111{
112 if (recv->r_ibinc) {
113 rds_inc_put(&recv->r_ibinc->ii_inc);
114 recv->r_ibinc = NULL;
115 }
116 if (recv->r_frag) {
117 rds_ib_recv_unmap_page(ic, recv);
118 if (recv->r_frag->f_page)
119 rds_ib_frag_drop_page(recv->r_frag);
120 rds_ib_frag_free(recv->r_frag);
121 recv->r_frag = NULL;
122 }
123}
124
125void rds_ib_recv_clear_ring(struct rds_ib_connection *ic)
126{
127 u32 i;
128
129 for (i = 0; i < ic->i_recv_ring.w_nr; i++)
130 rds_ib_recv_clear_one(ic, &ic->i_recvs[i]);
131
132 if (ic->i_frag.f_page)
133 rds_ib_frag_drop_page(&ic->i_frag);
134}
135
136static int rds_ib_recv_refill_one(struct rds_connection *conn,
137 struct rds_ib_recv_work *recv,
138 gfp_t kptr_gfp, gfp_t page_gfp)
139{
140 struct rds_ib_connection *ic = conn->c_transport_data;
141 dma_addr_t dma_addr;
142 struct ib_sge *sge;
143 int ret = -ENOMEM;
144
145 if (recv->r_ibinc == NULL) {
Andy Grover86357b12009-10-30 08:51:54 +0000146 if (!atomic_add_unless(&rds_ib_allocation, 1, rds_ib_sysctl_max_recv_allocation)) {
Andy Grover1e23b3e2009-02-24 15:30:34 +0000147 rds_ib_stats_inc(s_ib_rx_alloc_limit);
148 goto out;
149 }
150 recv->r_ibinc = kmem_cache_alloc(rds_ib_incoming_slab,
151 kptr_gfp);
Andy Grover86357b12009-10-30 08:51:54 +0000152 if (recv->r_ibinc == NULL) {
153 atomic_dec(&rds_ib_allocation);
Andy Grover1e23b3e2009-02-24 15:30:34 +0000154 goto out;
Andy Grover86357b12009-10-30 08:51:54 +0000155 }
Andy Grover1e23b3e2009-02-24 15:30:34 +0000156 INIT_LIST_HEAD(&recv->r_ibinc->ii_frags);
157 rds_inc_init(&recv->r_ibinc->ii_inc, conn, conn->c_faddr);
158 }
159
160 if (recv->r_frag == NULL) {
161 recv->r_frag = kmem_cache_alloc(rds_ib_frag_slab, kptr_gfp);
162 if (recv->r_frag == NULL)
163 goto out;
164 INIT_LIST_HEAD(&recv->r_frag->f_item);
165 recv->r_frag->f_page = NULL;
166 }
167
168 if (ic->i_frag.f_page == NULL) {
169 ic->i_frag.f_page = alloc_page(page_gfp);
170 if (ic->i_frag.f_page == NULL)
171 goto out;
172 ic->i_frag.f_offset = 0;
173 }
174
175 dma_addr = ib_dma_map_page(ic->i_cm_id->device,
176 ic->i_frag.f_page,
177 ic->i_frag.f_offset,
178 RDS_FRAG_SIZE,
179 DMA_FROM_DEVICE);
180 if (ib_dma_mapping_error(ic->i_cm_id->device, dma_addr))
181 goto out;
182
183 /*
184 * Once we get the RDS_PAGE_LAST_OFF frag then rds_ib_frag_unmap()
185 * must be called on this recv. This happens as completions hit
186 * in order or on connection shutdown.
187 */
188 recv->r_frag->f_page = ic->i_frag.f_page;
189 recv->r_frag->f_offset = ic->i_frag.f_offset;
190 recv->r_frag->f_mapped = dma_addr;
191
192 sge = rds_ib_data_sge(ic, recv->r_sge);
193 sge->addr = dma_addr;
194 sge->length = RDS_FRAG_SIZE;
195
196 sge = rds_ib_header_sge(ic, recv->r_sge);
197 sge->addr = ic->i_recv_hdrs_dma + (recv - ic->i_recvs) * sizeof(struct rds_header);
198 sge->length = sizeof(struct rds_header);
199
200 get_page(recv->r_frag->f_page);
201
202 if (ic->i_frag.f_offset < RDS_PAGE_LAST_OFF) {
203 ic->i_frag.f_offset += RDS_FRAG_SIZE;
204 } else {
205 put_page(ic->i_frag.f_page);
206 ic->i_frag.f_page = NULL;
207 ic->i_frag.f_offset = 0;
208 }
209
210 ret = 0;
211out:
212 return ret;
213}
214
215/*
216 * This tries to allocate and post unused work requests after making sure that
217 * they have all the allocations they need to queue received fragments into
218 * sockets. The i_recv_mutex is held here so that ring_alloc and _unalloc
219 * pairs don't go unmatched.
220 *
221 * -1 is returned if posting fails due to temporary resource exhaustion.
222 */
223int rds_ib_recv_refill(struct rds_connection *conn, gfp_t kptr_gfp,
224 gfp_t page_gfp, int prefill)
225{
226 struct rds_ib_connection *ic = conn->c_transport_data;
227 struct rds_ib_recv_work *recv;
228 struct ib_recv_wr *failed_wr;
229 unsigned int posted = 0;
230 int ret = 0;
231 u32 pos;
232
233 while ((prefill || rds_conn_up(conn))
234 && rds_ib_ring_alloc(&ic->i_recv_ring, 1, &pos)) {
235 if (pos >= ic->i_recv_ring.w_nr) {
236 printk(KERN_NOTICE "Argh - ring alloc returned pos=%u\n",
237 pos);
238 ret = -EINVAL;
239 break;
240 }
241
242 recv = &ic->i_recvs[pos];
243 ret = rds_ib_recv_refill_one(conn, recv, kptr_gfp, page_gfp);
244 if (ret) {
245 ret = -1;
246 break;
247 }
248
249 /* XXX when can this fail? */
250 ret = ib_post_recv(ic->i_cm_id->qp, &recv->r_wr, &failed_wr);
251 rdsdebug("recv %p ibinc %p page %p addr %lu ret %d\n", recv,
252 recv->r_ibinc, recv->r_frag->f_page,
253 (long) recv->r_frag->f_mapped, ret);
254 if (ret) {
255 rds_ib_conn_error(conn, "recv post on "
256 "%pI4 returned %d, disconnecting and "
257 "reconnecting\n", &conn->c_faddr,
258 ret);
259 ret = -1;
260 break;
261 }
262
263 posted++;
264 }
265
266 /* We're doing flow control - update the window. */
267 if (ic->i_flowctl && posted)
268 rds_ib_advertise_credits(conn, posted);
269
270 if (ret)
271 rds_ib_ring_unalloc(&ic->i_recv_ring, 1);
272 return ret;
273}
274
275void rds_ib_inc_purge(struct rds_incoming *inc)
276{
277 struct rds_ib_incoming *ibinc;
278 struct rds_page_frag *frag;
279 struct rds_page_frag *pos;
280
281 ibinc = container_of(inc, struct rds_ib_incoming, ii_inc);
282 rdsdebug("purging ibinc %p inc %p\n", ibinc, inc);
283
284 list_for_each_entry_safe(frag, pos, &ibinc->ii_frags, f_item) {
285 list_del_init(&frag->f_item);
286 rds_ib_frag_drop_page(frag);
287 rds_ib_frag_free(frag);
288 }
289}
290
291void rds_ib_inc_free(struct rds_incoming *inc)
292{
293 struct rds_ib_incoming *ibinc;
294
295 ibinc = container_of(inc, struct rds_ib_incoming, ii_inc);
296
297 rds_ib_inc_purge(inc);
298 rdsdebug("freeing ibinc %p inc %p\n", ibinc, inc);
299 BUG_ON(!list_empty(&ibinc->ii_frags));
300 kmem_cache_free(rds_ib_incoming_slab, ibinc);
301 atomic_dec(&rds_ib_allocation);
302 BUG_ON(atomic_read(&rds_ib_allocation) < 0);
303}
304
305int rds_ib_inc_copy_to_user(struct rds_incoming *inc, struct iovec *first_iov,
306 size_t size)
307{
308 struct rds_ib_incoming *ibinc;
309 struct rds_page_frag *frag;
310 struct iovec *iov = first_iov;
311 unsigned long to_copy;
312 unsigned long frag_off = 0;
313 unsigned long iov_off = 0;
314 int copied = 0;
315 int ret;
316 u32 len;
317
318 ibinc = container_of(inc, struct rds_ib_incoming, ii_inc);
319 frag = list_entry(ibinc->ii_frags.next, struct rds_page_frag, f_item);
320 len = be32_to_cpu(inc->i_hdr.h_len);
321
322 while (copied < size && copied < len) {
323 if (frag_off == RDS_FRAG_SIZE) {
324 frag = list_entry(frag->f_item.next,
325 struct rds_page_frag, f_item);
326 frag_off = 0;
327 }
328 while (iov_off == iov->iov_len) {
329 iov_off = 0;
330 iov++;
331 }
332
333 to_copy = min(iov->iov_len - iov_off, RDS_FRAG_SIZE - frag_off);
334 to_copy = min_t(size_t, to_copy, size - copied);
335 to_copy = min_t(unsigned long, to_copy, len - copied);
336
337 rdsdebug("%lu bytes to user [%p, %zu] + %lu from frag "
338 "[%p, %lu] + %lu\n",
339 to_copy, iov->iov_base, iov->iov_len, iov_off,
340 frag->f_page, frag->f_offset, frag_off);
341
342 /* XXX needs + offset for multiple recvs per page */
343 ret = rds_page_copy_to_user(frag->f_page,
344 frag->f_offset + frag_off,
345 iov->iov_base + iov_off,
346 to_copy);
347 if (ret) {
348 copied = ret;
349 break;
350 }
351
352 iov_off += to_copy;
353 frag_off += to_copy;
354 copied += to_copy;
355 }
356
357 return copied;
358}
359
360/* ic starts out kzalloc()ed */
361void rds_ib_recv_init_ack(struct rds_ib_connection *ic)
362{
363 struct ib_send_wr *wr = &ic->i_ack_wr;
364 struct ib_sge *sge = &ic->i_ack_sge;
365
366 sge->addr = ic->i_ack_dma;
367 sge->length = sizeof(struct rds_header);
368 sge->lkey = ic->i_mr->lkey;
369
370 wr->sg_list = sge;
371 wr->num_sge = 1;
372 wr->opcode = IB_WR_SEND;
373 wr->wr_id = RDS_IB_ACK_WR_ID;
374 wr->send_flags = IB_SEND_SIGNALED | IB_SEND_SOLICITED;
375}
376
377/*
378 * You'd think that with reliable IB connections you wouldn't need to ack
379 * messages that have been received. The problem is that IB hardware generates
380 * an ack message before it has DMAed the message into memory. This creates a
381 * potential message loss if the HCA is disabled for any reason between when it
382 * sends the ack and before the message is DMAed and processed. This is only a
383 * potential issue if another HCA is available for fail-over.
384 *
385 * When the remote host receives our ack they'll free the sent message from
386 * their send queue. To decrease the latency of this we always send an ack
387 * immediately after we've received messages.
388 *
389 * For simplicity, we only have one ack in flight at a time. This puts
390 * pressure on senders to have deep enough send queues to absorb the latency of
391 * a single ack frame being in flight. This might not be good enough.
392 *
393 * This is implemented by have a long-lived send_wr and sge which point to a
394 * statically allocated ack frame. This ack wr does not fall under the ring
395 * accounting that the tx and rx wrs do. The QP attribute specifically makes
396 * room for it beyond the ring size. Send completion notices its special
397 * wr_id and avoids working with the ring in that case.
398 */
Andy Grover8cbd9602009-04-01 08:20:20 +0000399#ifndef KERNEL_HAS_ATOMIC64
Andy Grover1e23b3e2009-02-24 15:30:34 +0000400static void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq,
401 int ack_required)
402{
Andy Grover8cbd9602009-04-01 08:20:20 +0000403 unsigned long flags;
404
405 spin_lock_irqsave(&ic->i_ack_lock, flags);
406 ic->i_ack_next = seq;
407 if (ack_required)
408 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
409 spin_unlock_irqrestore(&ic->i_ack_lock, flags);
410}
411
412static u64 rds_ib_get_ack(struct rds_ib_connection *ic)
413{
414 unsigned long flags;
415 u64 seq;
416
417 clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
418
419 spin_lock_irqsave(&ic->i_ack_lock, flags);
420 seq = ic->i_ack_next;
421 spin_unlock_irqrestore(&ic->i_ack_lock, flags);
422
423 return seq;
424}
425#else
426static void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq,
427 int ack_required)
428{
429 atomic64_set(&ic->i_ack_next, seq);
Andy Grover1e23b3e2009-02-24 15:30:34 +0000430 if (ack_required) {
431 smp_mb__before_clear_bit();
432 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
433 }
434}
435
436static u64 rds_ib_get_ack(struct rds_ib_connection *ic)
437{
438 clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
439 smp_mb__after_clear_bit();
440
Andy Grover8cbd9602009-04-01 08:20:20 +0000441 return atomic64_read(&ic->i_ack_next);
Andy Grover1e23b3e2009-02-24 15:30:34 +0000442}
Andy Grover8cbd9602009-04-01 08:20:20 +0000443#endif
444
Andy Grover1e23b3e2009-02-24 15:30:34 +0000445
446static void rds_ib_send_ack(struct rds_ib_connection *ic, unsigned int adv_credits)
447{
448 struct rds_header *hdr = ic->i_ack;
449 struct ib_send_wr *failed_wr;
450 u64 seq;
451 int ret;
452
453 seq = rds_ib_get_ack(ic);
454
455 rdsdebug("send_ack: ic %p ack %llu\n", ic, (unsigned long long) seq);
456 rds_message_populate_header(hdr, 0, 0, 0);
457 hdr->h_ack = cpu_to_be64(seq);
458 hdr->h_credit = adv_credits;
459 rds_message_make_checksum(hdr);
460 ic->i_ack_queued = jiffies;
461
462 ret = ib_post_send(ic->i_cm_id->qp, &ic->i_ack_wr, &failed_wr);
463 if (unlikely(ret)) {
464 /* Failed to send. Release the WR, and
465 * force another ACK.
466 */
467 clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
468 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
469
470 rds_ib_stats_inc(s_ib_ack_send_failure);
471 /* Need to finesse this later. */
472 BUG();
473 } else
474 rds_ib_stats_inc(s_ib_ack_sent);
475}
476
477/*
478 * There are 3 ways of getting acknowledgements to the peer:
479 * 1. We call rds_ib_attempt_ack from the recv completion handler
480 * to send an ACK-only frame.
481 * However, there can be only one such frame in the send queue
482 * at any time, so we may have to postpone it.
483 * 2. When another (data) packet is transmitted while there's
484 * an ACK in the queue, we piggyback the ACK sequence number
485 * on the data packet.
486 * 3. If the ACK WR is done sending, we get called from the
487 * send queue completion handler, and check whether there's
488 * another ACK pending (postponed because the WR was on the
489 * queue). If so, we transmit it.
490 *
491 * We maintain 2 variables:
492 * - i_ack_flags, which keeps track of whether the ACK WR
493 * is currently in the send queue or not (IB_ACK_IN_FLIGHT)
494 * - i_ack_next, which is the last sequence number we received
495 *
496 * Potentially, send queue and receive queue handlers can run concurrently.
Andy Grover8cbd9602009-04-01 08:20:20 +0000497 * It would be nice to not have to use a spinlock to synchronize things,
498 * but the one problem that rules this out is that 64bit updates are
499 * not atomic on all platforms. Things would be a lot simpler if
500 * we had atomic64 or maybe cmpxchg64 everywhere.
Andy Grover1e23b3e2009-02-24 15:30:34 +0000501 *
502 * Reconnecting complicates this picture just slightly. When we
503 * reconnect, we may be seeing duplicate packets. The peer
504 * is retransmitting them, because it hasn't seen an ACK for
505 * them. It is important that we ACK these.
506 *
507 * ACK mitigation adds a header flag "ACK_REQUIRED"; any packet with
508 * this flag set *MUST* be acknowledged immediately.
509 */
510
511/*
512 * When we get here, we're called from the recv queue handler.
513 * Check whether we ought to transmit an ACK.
514 */
515void rds_ib_attempt_ack(struct rds_ib_connection *ic)
516{
517 unsigned int adv_credits;
518
519 if (!test_bit(IB_ACK_REQUESTED, &ic->i_ack_flags))
520 return;
521
522 if (test_and_set_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags)) {
523 rds_ib_stats_inc(s_ib_ack_send_delayed);
524 return;
525 }
526
527 /* Can we get a send credit? */
Steve Wise7b70d032009-04-09 14:09:39 +0000528 if (!rds_ib_send_grab_credits(ic, 1, &adv_credits, 0, RDS_MAX_ADV_CREDIT)) {
Andy Grover1e23b3e2009-02-24 15:30:34 +0000529 rds_ib_stats_inc(s_ib_tx_throttle);
530 clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
531 return;
532 }
533
534 clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
535 rds_ib_send_ack(ic, adv_credits);
536}
537
538/*
539 * We get here from the send completion handler, when the
540 * adapter tells us the ACK frame was sent.
541 */
542void rds_ib_ack_send_complete(struct rds_ib_connection *ic)
543{
544 clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
545 rds_ib_attempt_ack(ic);
546}
547
548/*
549 * This is called by the regular xmit code when it wants to piggyback
550 * an ACK on an outgoing frame.
551 */
552u64 rds_ib_piggyb_ack(struct rds_ib_connection *ic)
553{
554 if (test_and_clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags))
555 rds_ib_stats_inc(s_ib_ack_send_piggybacked);
556 return rds_ib_get_ack(ic);
557}
558
Andy Grover02a6a252009-07-17 13:13:24 +0000559static struct rds_header *rds_ib_get_header(struct rds_connection *conn,
560 struct rds_ib_recv_work *recv,
561 u32 data_len)
562{
563 struct rds_ib_connection *ic = conn->c_transport_data;
564 void *hdr_buff = &ic->i_recv_hdrs[recv - ic->i_recvs];
565 void *addr;
566 u32 misplaced_hdr_bytes;
567
568 /*
569 * Support header at the front (RDS 3.1+) as well as header-at-end.
570 *
571 * Cases:
572 * 1) header all in header buff (great!)
573 * 2) header all in data page (copy all to header buff)
574 * 3) header split across hdr buf + data page
575 * (move bit in hdr buff to end before copying other bit from data page)
576 */
577 if (conn->c_version > RDS_PROTOCOL_3_0 || data_len == RDS_FRAG_SIZE)
578 return hdr_buff;
579
580 if (data_len <= (RDS_FRAG_SIZE - sizeof(struct rds_header))) {
581 addr = kmap_atomic(recv->r_frag->f_page, KM_SOFTIRQ0);
582 memcpy(hdr_buff,
583 addr + recv->r_frag->f_offset + data_len,
584 sizeof(struct rds_header));
585 kunmap_atomic(addr, KM_SOFTIRQ0);
586 return hdr_buff;
587 }
588
589 misplaced_hdr_bytes = (sizeof(struct rds_header) - (RDS_FRAG_SIZE - data_len));
590
591 memmove(hdr_buff + misplaced_hdr_bytes, hdr_buff, misplaced_hdr_bytes);
592
593 addr = kmap_atomic(recv->r_frag->f_page, KM_SOFTIRQ0);
594 memcpy(hdr_buff, addr + recv->r_frag->f_offset + data_len,
595 sizeof(struct rds_header) - misplaced_hdr_bytes);
596 kunmap_atomic(addr, KM_SOFTIRQ0);
597 return hdr_buff;
598}
599
Andy Grover1e23b3e2009-02-24 15:30:34 +0000600/*
601 * It's kind of lame that we're copying from the posted receive pages into
602 * long-lived bitmaps. We could have posted the bitmaps and rdma written into
603 * them. But receiving new congestion bitmaps should be a *rare* event, so
604 * hopefully we won't need to invest that complexity in making it more
605 * efficient. By copying we can share a simpler core with TCP which has to
606 * copy.
607 */
608static void rds_ib_cong_recv(struct rds_connection *conn,
609 struct rds_ib_incoming *ibinc)
610{
611 struct rds_cong_map *map;
612 unsigned int map_off;
613 unsigned int map_page;
614 struct rds_page_frag *frag;
615 unsigned long frag_off;
616 unsigned long to_copy;
617 unsigned long copied;
618 uint64_t uncongested = 0;
619 void *addr;
620
621 /* catch completely corrupt packets */
622 if (be32_to_cpu(ibinc->ii_inc.i_hdr.h_len) != RDS_CONG_MAP_BYTES)
623 return;
624
625 map = conn->c_fcong;
626 map_page = 0;
627 map_off = 0;
628
629 frag = list_entry(ibinc->ii_frags.next, struct rds_page_frag, f_item);
630 frag_off = 0;
631
632 copied = 0;
633
634 while (copied < RDS_CONG_MAP_BYTES) {
635 uint64_t *src, *dst;
636 unsigned int k;
637
638 to_copy = min(RDS_FRAG_SIZE - frag_off, PAGE_SIZE - map_off);
639 BUG_ON(to_copy & 7); /* Must be 64bit aligned. */
640
641 addr = kmap_atomic(frag->f_page, KM_SOFTIRQ0);
642
643 src = addr + frag_off;
644 dst = (void *)map->m_page_addrs[map_page] + map_off;
645 for (k = 0; k < to_copy; k += 8) {
646 /* Record ports that became uncongested, ie
647 * bits that changed from 0 to 1. */
648 uncongested |= ~(*src) & *dst;
649 *dst++ = *src++;
650 }
651 kunmap_atomic(addr, KM_SOFTIRQ0);
652
653 copied += to_copy;
654
655 map_off += to_copy;
656 if (map_off == PAGE_SIZE) {
657 map_off = 0;
658 map_page++;
659 }
660
661 frag_off += to_copy;
662 if (frag_off == RDS_FRAG_SIZE) {
663 frag = list_entry(frag->f_item.next,
664 struct rds_page_frag, f_item);
665 frag_off = 0;
666 }
667 }
668
669 /* the congestion map is in little endian order */
670 uncongested = le64_to_cpu(uncongested);
671
672 rds_cong_map_updated(map, uncongested);
673}
674
675/*
676 * Rings are posted with all the allocations they'll need to queue the
677 * incoming message to the receiving socket so this can't fail.
678 * All fragments start with a header, so we can make sure we're not receiving
679 * garbage, and we can tell a small 8 byte fragment from an ACK frame.
680 */
681struct rds_ib_ack_state {
682 u64 ack_next;
683 u64 ack_recv;
684 unsigned int ack_required:1;
685 unsigned int ack_next_valid:1;
686 unsigned int ack_recv_valid:1;
687};
688
689static void rds_ib_process_recv(struct rds_connection *conn,
Andy Grover597ddd52009-07-17 13:13:27 +0000690 struct rds_ib_recv_work *recv, u32 data_len,
Andy Grover1e23b3e2009-02-24 15:30:34 +0000691 struct rds_ib_ack_state *state)
692{
693 struct rds_ib_connection *ic = conn->c_transport_data;
694 struct rds_ib_incoming *ibinc = ic->i_ibinc;
695 struct rds_header *ihdr, *hdr;
696
697 /* XXX shut down the connection if port 0,0 are seen? */
698
699 rdsdebug("ic %p ibinc %p recv %p byte len %u\n", ic, ibinc, recv,
Andy Grover597ddd52009-07-17 13:13:27 +0000700 data_len);
Andy Grover1e23b3e2009-02-24 15:30:34 +0000701
Andy Grover597ddd52009-07-17 13:13:27 +0000702 if (data_len < sizeof(struct rds_header)) {
Andy Grover1e23b3e2009-02-24 15:30:34 +0000703 rds_ib_conn_error(conn, "incoming message "
704 "from %pI4 didn't inclue a "
705 "header, disconnecting and "
706 "reconnecting\n",
707 &conn->c_faddr);
708 return;
709 }
Andy Grover597ddd52009-07-17 13:13:27 +0000710 data_len -= sizeof(struct rds_header);
Andy Grover1e23b3e2009-02-24 15:30:34 +0000711
Andy Grover597ddd52009-07-17 13:13:27 +0000712 ihdr = rds_ib_get_header(conn, recv, data_len);
Andy Grover1e23b3e2009-02-24 15:30:34 +0000713
714 /* Validate the checksum. */
715 if (!rds_message_verify_checksum(ihdr)) {
716 rds_ib_conn_error(conn, "incoming message "
717 "from %pI4 has corrupted header - "
718 "forcing a reconnect\n",
719 &conn->c_faddr);
720 rds_stats_inc(s_recv_drop_bad_checksum);
721 return;
722 }
723
724 /* Process the ACK sequence which comes with every packet */
725 state->ack_recv = be64_to_cpu(ihdr->h_ack);
726 state->ack_recv_valid = 1;
727
728 /* Process the credits update if there was one */
729 if (ihdr->h_credit)
730 rds_ib_send_add_credits(conn, ihdr->h_credit);
731
Andy Grover597ddd52009-07-17 13:13:27 +0000732 if (ihdr->h_sport == 0 && ihdr->h_dport == 0 && data_len == 0) {
Andy Grover1e23b3e2009-02-24 15:30:34 +0000733 /* This is an ACK-only packet. The fact that it gets
734 * special treatment here is that historically, ACKs
735 * were rather special beasts.
736 */
737 rds_ib_stats_inc(s_ib_ack_received);
738
739 /*
740 * Usually the frags make their way on to incs and are then freed as
741 * the inc is freed. We don't go that route, so we have to drop the
742 * page ref ourselves. We can't just leave the page on the recv
743 * because that confuses the dma mapping of pages and each recv's use
744 * of a partial page. We can leave the frag, though, it will be
745 * reused.
746 *
747 * FIXME: Fold this into the code path below.
748 */
749 rds_ib_frag_drop_page(recv->r_frag);
750 return;
751 }
752
753 /*
754 * If we don't already have an inc on the connection then this
755 * fragment has a header and starts a message.. copy its header
756 * into the inc and save the inc so we can hang upcoming fragments
757 * off its list.
758 */
759 if (ibinc == NULL) {
760 ibinc = recv->r_ibinc;
761 recv->r_ibinc = NULL;
762 ic->i_ibinc = ibinc;
763
764 hdr = &ibinc->ii_inc.i_hdr;
765 memcpy(hdr, ihdr, sizeof(*hdr));
766 ic->i_recv_data_rem = be32_to_cpu(hdr->h_len);
767
768 rdsdebug("ic %p ibinc %p rem %u flag 0x%x\n", ic, ibinc,
769 ic->i_recv_data_rem, hdr->h_flags);
770 } else {
771 hdr = &ibinc->ii_inc.i_hdr;
772 /* We can't just use memcmp here; fragments of a
773 * single message may carry different ACKs */
774 if (hdr->h_sequence != ihdr->h_sequence
775 || hdr->h_len != ihdr->h_len
776 || hdr->h_sport != ihdr->h_sport
777 || hdr->h_dport != ihdr->h_dport) {
778 rds_ib_conn_error(conn,
779 "fragment header mismatch; forcing reconnect\n");
780 return;
781 }
782 }
783
784 list_add_tail(&recv->r_frag->f_item, &ibinc->ii_frags);
785 recv->r_frag = NULL;
786
787 if (ic->i_recv_data_rem > RDS_FRAG_SIZE)
788 ic->i_recv_data_rem -= RDS_FRAG_SIZE;
789 else {
790 ic->i_recv_data_rem = 0;
791 ic->i_ibinc = NULL;
792
793 if (ibinc->ii_inc.i_hdr.h_flags == RDS_FLAG_CONG_BITMAP)
794 rds_ib_cong_recv(conn, ibinc);
795 else {
796 rds_recv_incoming(conn, conn->c_faddr, conn->c_laddr,
797 &ibinc->ii_inc, GFP_ATOMIC,
798 KM_SOFTIRQ0);
799 state->ack_next = be64_to_cpu(hdr->h_sequence);
800 state->ack_next_valid = 1;
801 }
802
803 /* Evaluate the ACK_REQUIRED flag *after* we received
804 * the complete frame, and after bumping the next_rx
805 * sequence. */
806 if (hdr->h_flags & RDS_FLAG_ACK_REQUIRED) {
807 rds_stats_inc(s_recv_ack_required);
808 state->ack_required = 1;
809 }
810
811 rds_inc_put(&ibinc->ii_inc);
812 }
813}
814
815/*
816 * Plucking the oldest entry from the ring can be done concurrently with
817 * the thread refilling the ring. Each ring operation is protected by
818 * spinlocks and the transient state of refilling doesn't change the
819 * recording of which entry is oldest.
820 *
821 * This relies on IB only calling one cq comp_handler for each cq so that
822 * there will only be one caller of rds_recv_incoming() per RDS connection.
823 */
824void rds_ib_recv_cq_comp_handler(struct ib_cq *cq, void *context)
825{
826 struct rds_connection *conn = context;
827 struct rds_ib_connection *ic = conn->c_transport_data;
828 struct ib_wc wc;
829 struct rds_ib_ack_state state = { 0, };
830 struct rds_ib_recv_work *recv;
831
832 rdsdebug("conn %p cq %p\n", conn, cq);
833
834 rds_ib_stats_inc(s_ib_rx_cq_call);
835
836 ib_req_notify_cq(cq, IB_CQ_SOLICITED);
837
838 while (ib_poll_cq(cq, 1, &wc) > 0) {
839 rdsdebug("wc wr_id 0x%llx status %u byte_len %u imm_data %u\n",
840 (unsigned long long)wc.wr_id, wc.status, wc.byte_len,
841 be32_to_cpu(wc.ex.imm_data));
842 rds_ib_stats_inc(s_ib_rx_cq_event);
843
844 recv = &ic->i_recvs[rds_ib_ring_oldest(&ic->i_recv_ring)];
845
846 rds_ib_recv_unmap_page(ic, recv);
847
848 /*
849 * Also process recvs in connecting state because it is possible
850 * to get a recv completion _before_ the rdmacm ESTABLISHED
851 * event is processed.
852 */
853 if (rds_conn_up(conn) || rds_conn_connecting(conn)) {
854 /* We expect errors as the qp is drained during shutdown */
855 if (wc.status == IB_WC_SUCCESS) {
856 rds_ib_process_recv(conn, recv, wc.byte_len, &state);
857 } else {
858 rds_ib_conn_error(conn, "recv completion on "
859 "%pI4 had status %u, disconnecting and "
860 "reconnecting\n", &conn->c_faddr,
861 wc.status);
862 }
863 }
864
865 rds_ib_ring_free(&ic->i_recv_ring, 1);
866 }
867
868 if (state.ack_next_valid)
869 rds_ib_set_ack(ic, state.ack_next, state.ack_required);
870 if (state.ack_recv_valid && state.ack_recv > ic->i_ack_recv) {
871 rds_send_drop_acked(conn, state.ack_recv, NULL);
872 ic->i_ack_recv = state.ack_recv;
873 }
874 if (rds_conn_up(conn))
875 rds_ib_attempt_ack(ic);
876
877 /* If we ever end up with a really empty receive ring, we're
878 * in deep trouble, as the sender will definitely see RNR
879 * timeouts. */
880 if (rds_ib_ring_empty(&ic->i_recv_ring))
881 rds_ib_stats_inc(s_ib_rx_ring_empty);
882
883 /*
884 * If the ring is running low, then schedule the thread to refill.
885 */
886 if (rds_ib_ring_low(&ic->i_recv_ring))
887 queue_delayed_work(rds_wq, &conn->c_recv_w, 0);
888}
889
890int rds_ib_recv(struct rds_connection *conn)
891{
892 struct rds_ib_connection *ic = conn->c_transport_data;
893 int ret = 0;
894
895 rdsdebug("conn %p\n", conn);
896
897 /*
898 * If we get a temporary posting failure in this context then
899 * we're really low and we want the caller to back off for a bit.
900 */
901 mutex_lock(&ic->i_recv_mutex);
902 if (rds_ib_recv_refill(conn, GFP_KERNEL, GFP_HIGHUSER, 0))
903 ret = -ENOMEM;
904 else
905 rds_ib_stats_inc(s_ib_rx_refill_from_thread);
906 mutex_unlock(&ic->i_recv_mutex);
907
908 if (rds_conn_up(conn))
909 rds_ib_attempt_ack(ic);
910
911 return ret;
912}
913
914int __init rds_ib_recv_init(void)
915{
916 struct sysinfo si;
917 int ret = -ENOMEM;
918
919 /* Default to 30% of all available RAM for recv memory */
920 si_meminfo(&si);
921 rds_ib_sysctl_max_recv_allocation = si.totalram / 3 * PAGE_SIZE / RDS_FRAG_SIZE;
922
923 rds_ib_incoming_slab = kmem_cache_create("rds_ib_incoming",
924 sizeof(struct rds_ib_incoming),
925 0, 0, NULL);
926 if (rds_ib_incoming_slab == NULL)
927 goto out;
928
929 rds_ib_frag_slab = kmem_cache_create("rds_ib_frag",
930 sizeof(struct rds_page_frag),
931 0, 0, NULL);
932 if (rds_ib_frag_slab == NULL)
933 kmem_cache_destroy(rds_ib_incoming_slab);
934 else
935 ret = 0;
936out:
937 return ret;
938}
939
940void rds_ib_recv_exit(void)
941{
942 kmem_cache_destroy(rds_ib_incoming_slab);
943 kmem_cache_destroy(rds_ib_frag_slab);
944}