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1 | /* |
2 | * Copyright (c) 2006 Oracle. All rights reserved. |
3 | * |
4 | * This software is available to you under a choice of one of two |
5 | * licenses. You may choose to be licensed under the terms of the GNU |
6 | * General Public License (GPL) Version 2, available from the file |
7 | * COPYING in the main directory of this source tree, or the |
8 | * OpenIB.org BSD license below: |
9 | * |
10 | * Redistribution and use in source and binary forms, with or |
11 | * without modification, are permitted provided that the following |
12 | * conditions are met: |
13 | * |
14 | * - Redistributions of source code must retain the above |
15 | * copyright notice, this list of conditions and the following |
16 | * disclaimer. |
17 | * |
18 | * - Redistributions in binary form must reproduce the above |
19 | * copyright notice, this list of conditions and the following |
20 | * disclaimer in the documentation and/or other materials |
21 | * provided with the distribution. |
22 | * |
23 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
24 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
25 | * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
26 | * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS |
27 | * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN |
28 | * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN |
29 | * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
30 | * SOFTWARE. |
31 | * |
32 | */ |
33 | #include <linux/kernel.h> |
34 | #include <linux/slab.h> |
35 | #include <linux/pci.h> |
36 | #include <linux/dma-mapping.h> |
37 | #include <rdma/rdma_cm.h> |
38 | |
39 | #include "rds.h" |
40 | #include "ib.h" |
41 | |
42 | static struct kmem_cache *rds_ib_incoming_slab; |
43 | static struct kmem_cache *rds_ib_frag_slab; |
44 | static atomic_t rds_ib_allocation = ATOMIC_INIT(0); |
45 | |
46 | static void rds_ib_frag_drop_page(struct rds_page_frag *frag) |
47 | { |
48 | rdsdebug("frag %p page %p\n", frag, frag->f_page); |
49 | __free_page(frag->f_page); |
50 | frag->f_page = NULL; |
51 | } |
52 | |
53 | static void rds_ib_frag_free(struct rds_page_frag *frag) |
54 | { |
55 | rdsdebug("frag %p page %p\n", frag, frag->f_page); |
56 | BUG_ON(frag->f_page != NULL); |
57 | kmem_cache_free(rds_ib_frag_slab, frag); |
58 | } |
59 | |
60 | /* |
61 | * We map a page at a time. Its fragments are posted in order. This |
62 | * is called in fragment order as the fragments get send completion events. |
63 | * Only the last frag in the page performs the unmapping. |
64 | * |
65 | * It's OK for ring cleanup to call this in whatever order it likes because |
66 | * DMA is not in flight and so we can unmap while other ring entries still |
67 | * hold page references in their frags. |
68 | */ |
69 | static void rds_ib_recv_unmap_page(struct rds_ib_connection *ic, |
70 | struct rds_ib_recv_work *recv) |
71 | { |
72 | struct rds_page_frag *frag = recv->r_frag; |
73 | |
74 | rdsdebug("recv %p frag %p page %p\n", recv, frag, frag->f_page); |
75 | if (frag->f_mapped) |
76 | ib_dma_unmap_page(ic->i_cm_id->device, |
77 | frag->f_mapped, |
78 | RDS_FRAG_SIZE, DMA_FROM_DEVICE); |
79 | frag->f_mapped = 0; |
80 | } |
81 | |
82 | void rds_ib_recv_init_ring(struct rds_ib_connection *ic) |
83 | { |
84 | struct rds_ib_recv_work *recv; |
85 | u32 i; |
86 | |
87 | for (i = 0, recv = ic->i_recvs; i < ic->i_recv_ring.w_nr; i++, recv++) { |
88 | struct ib_sge *sge; |
89 | |
90 | recv->r_ibinc = NULL; |
91 | recv->r_frag = NULL; |
92 | |
93 | recv->r_wr.next = NULL; |
94 | recv->r_wr.wr_id = i; |
95 | recv->r_wr.sg_list = recv->r_sge; |
96 | recv->r_wr.num_sge = RDS_IB_RECV_SGE; |
97 | |
98 | sge = rds_ib_data_sge(ic, recv->r_sge); |
99 | sge->addr = 0; |
100 | sge->length = RDS_FRAG_SIZE; |
101 | sge->lkey = ic->i_mr->lkey; |
102 | |
103 | sge = rds_ib_header_sge(ic, recv->r_sge); |
104 | sge->addr = ic->i_recv_hdrs_dma + (i * sizeof(struct rds_header)); |
105 | sge->length = sizeof(struct rds_header); |
106 | sge->lkey = ic->i_mr->lkey; |
107 | } |
108 | } |
109 | |
110 | static void rds_ib_recv_clear_one(struct rds_ib_connection *ic, |
111 | struct rds_ib_recv_work *recv) |
112 | { |
113 | if (recv->r_ibinc) { |
114 | rds_inc_put(&recv->r_ibinc->ii_inc); |
115 | recv->r_ibinc = NULL; |
116 | } |
117 | if (recv->r_frag) { |
118 | rds_ib_recv_unmap_page(ic, recv); |
119 | if (recv->r_frag->f_page) |
120 | rds_ib_frag_drop_page(recv->r_frag); |
121 | rds_ib_frag_free(recv->r_frag); |
122 | recv->r_frag = NULL; |
123 | } |
124 | } |
125 | |
126 | void rds_ib_recv_clear_ring(struct rds_ib_connection *ic) |
127 | { |
128 | u32 i; |
129 | |
130 | for (i = 0; i < ic->i_recv_ring.w_nr; i++) |
131 | rds_ib_recv_clear_one(ic, &ic->i_recvs[i]); |
132 | |
133 | if (ic->i_frag.f_page) |
134 | rds_ib_frag_drop_page(&ic->i_frag); |
135 | } |
136 | |
137 | static int rds_ib_recv_refill_one(struct rds_connection *conn, |
138 | struct rds_ib_recv_work *recv, |
139 | gfp_t kptr_gfp, gfp_t page_gfp) |
140 | { |
141 | struct rds_ib_connection *ic = conn->c_transport_data; |
142 | dma_addr_t dma_addr; |
143 | struct ib_sge *sge; |
144 | int ret = -ENOMEM; |
145 | |
146 | if (recv->r_ibinc == NULL) { |
147 | if (!atomic_add_unless(&rds_ib_allocation, 1, rds_ib_sysctl_max_recv_allocation)) { |
148 | rds_ib_stats_inc(s_ib_rx_alloc_limit); |
149 | goto out; |
150 | } |
151 | recv->r_ibinc = kmem_cache_alloc(rds_ib_incoming_slab, |
152 | kptr_gfp); |
153 | if (recv->r_ibinc == NULL) { |
154 | atomic_dec(&rds_ib_allocation); |
155 | goto out; |
156 | } |
157 | INIT_LIST_HEAD(&recv->r_ibinc->ii_frags); |
158 | rds_inc_init(&recv->r_ibinc->ii_inc, conn, conn->c_faddr); |
159 | } |
160 | |
161 | if (recv->r_frag == NULL) { |
162 | recv->r_frag = kmem_cache_alloc(rds_ib_frag_slab, kptr_gfp); |
163 | if (recv->r_frag == NULL) |
164 | goto out; |
165 | INIT_LIST_HEAD(&recv->r_frag->f_item); |
166 | recv->r_frag->f_page = NULL; |
167 | } |
168 | |
169 | if (ic->i_frag.f_page == NULL) { |
170 | ic->i_frag.f_page = alloc_page(page_gfp); |
171 | if (ic->i_frag.f_page == NULL) |
172 | goto out; |
173 | ic->i_frag.f_offset = 0; |
174 | } |
175 | |
176 | dma_addr = ib_dma_map_page(ic->i_cm_id->device, |
177 | ic->i_frag.f_page, |
178 | ic->i_frag.f_offset, |
179 | RDS_FRAG_SIZE, |
180 | DMA_FROM_DEVICE); |
181 | if (ib_dma_mapping_error(ic->i_cm_id->device, dma_addr)) |
182 | goto out; |
183 | |
184 | /* |
185 | * Once we get the RDS_PAGE_LAST_OFF frag then rds_ib_frag_unmap() |
186 | * must be called on this recv. This happens as completions hit |
187 | * in order or on connection shutdown. |
188 | */ |
189 | recv->r_frag->f_page = ic->i_frag.f_page; |
190 | recv->r_frag->f_offset = ic->i_frag.f_offset; |
191 | recv->r_frag->f_mapped = dma_addr; |
192 | |
193 | sge = rds_ib_data_sge(ic, recv->r_sge); |
194 | sge->addr = dma_addr; |
195 | sge->length = RDS_FRAG_SIZE; |
196 | |
197 | sge = rds_ib_header_sge(ic, recv->r_sge); |
198 | sge->addr = ic->i_recv_hdrs_dma + (recv - ic->i_recvs) * sizeof(struct rds_header); |
199 | sge->length = sizeof(struct rds_header); |
200 | |
201 | get_page(recv->r_frag->f_page); |
202 | |
203 | if (ic->i_frag.f_offset < RDS_PAGE_LAST_OFF) { |
204 | ic->i_frag.f_offset += RDS_FRAG_SIZE; |
205 | } else { |
206 | put_page(ic->i_frag.f_page); |
207 | ic->i_frag.f_page = NULL; |
208 | ic->i_frag.f_offset = 0; |
209 | } |
210 | |
211 | ret = 0; |
212 | out: |
213 | return ret; |
214 | } |
215 | |
216 | /* |
217 | * This tries to allocate and post unused work requests after making sure that |
218 | * they have all the allocations they need to queue received fragments into |
219 | * sockets. The i_recv_mutex is held here so that ring_alloc and _unalloc |
220 | * pairs don't go unmatched. |
221 | * |
222 | * -1 is returned if posting fails due to temporary resource exhaustion. |
223 | */ |
224 | int rds_ib_recv_refill(struct rds_connection *conn, gfp_t kptr_gfp, |
225 | gfp_t page_gfp, int prefill) |
226 | { |
227 | struct rds_ib_connection *ic = conn->c_transport_data; |
228 | struct rds_ib_recv_work *recv; |
229 | struct ib_recv_wr *failed_wr; |
230 | unsigned int posted = 0; |
231 | int ret = 0; |
232 | u32 pos; |
233 | |
234 | while ((prefill || rds_conn_up(conn)) && |
235 | rds_ib_ring_alloc(&ic->i_recv_ring, 1, &pos)) { |
236 | if (pos >= ic->i_recv_ring.w_nr) { |
237 | printk(KERN_NOTICE "Argh - ring alloc returned pos=%u\n", |
238 | pos); |
239 | ret = -EINVAL; |
240 | break; |
241 | } |
242 | |
243 | recv = &ic->i_recvs[pos]; |
244 | ret = rds_ib_recv_refill_one(conn, recv, kptr_gfp, page_gfp); |
245 | if (ret) { |
246 | ret = -1; |
247 | break; |
248 | } |
249 | |
250 | /* XXX when can this fail? */ |
251 | ret = ib_post_recv(ic->i_cm_id->qp, &recv->r_wr, &failed_wr); |
252 | rdsdebug("recv %p ibinc %p page %p addr %lu ret %d\n", recv, |
253 | recv->r_ibinc, recv->r_frag->f_page, |
254 | (long) recv->r_frag->f_mapped, ret); |
255 | if (ret) { |
256 | rds_ib_conn_error(conn, "recv post on " |
257 | "%pI4 returned %d, disconnecting and " |
258 | "reconnecting\n", &conn->c_faddr, |
259 | ret); |
260 | ret = -1; |
261 | break; |
262 | } |
263 | |
264 | posted++; |
265 | } |
266 | |
267 | /* We're doing flow control - update the window. */ |
268 | if (ic->i_flowctl && posted) |
269 | rds_ib_advertise_credits(conn, posted); |
270 | |
271 | if (ret) |
272 | rds_ib_ring_unalloc(&ic->i_recv_ring, 1); |
273 | return ret; |
274 | } |
275 | |
276 | void rds_ib_inc_purge(struct rds_incoming *inc) |
277 | { |
278 | struct rds_ib_incoming *ibinc; |
279 | struct rds_page_frag *frag; |
280 | struct rds_page_frag *pos; |
281 | |
282 | ibinc = container_of(inc, struct rds_ib_incoming, ii_inc); |
283 | rdsdebug("purging ibinc %p inc %p\n", ibinc, inc); |
284 | |
285 | list_for_each_entry_safe(frag, pos, &ibinc->ii_frags, f_item) { |
286 | list_del_init(&frag->f_item); |
287 | rds_ib_frag_drop_page(frag); |
288 | rds_ib_frag_free(frag); |
289 | } |
290 | } |
291 | |
292 | void rds_ib_inc_free(struct rds_incoming *inc) |
293 | { |
294 | struct rds_ib_incoming *ibinc; |
295 | |
296 | ibinc = container_of(inc, struct rds_ib_incoming, ii_inc); |
297 | |
298 | rds_ib_inc_purge(inc); |
299 | rdsdebug("freeing ibinc %p inc %p\n", ibinc, inc); |
300 | BUG_ON(!list_empty(&ibinc->ii_frags)); |
301 | kmem_cache_free(rds_ib_incoming_slab, ibinc); |
302 | atomic_dec(&rds_ib_allocation); |
303 | BUG_ON(atomic_read(&rds_ib_allocation) < 0); |
304 | } |
305 | |
306 | int rds_ib_inc_copy_to_user(struct rds_incoming *inc, struct iovec *first_iov, |
307 | size_t size) |
308 | { |
309 | struct rds_ib_incoming *ibinc; |
310 | struct rds_page_frag *frag; |
311 | struct iovec *iov = first_iov; |
312 | unsigned long to_copy; |
313 | unsigned long frag_off = 0; |
314 | unsigned long iov_off = 0; |
315 | int copied = 0; |
316 | int ret; |
317 | u32 len; |
318 | |
319 | ibinc = container_of(inc, struct rds_ib_incoming, ii_inc); |
320 | frag = list_entry(ibinc->ii_frags.next, struct rds_page_frag, f_item); |
321 | len = be32_to_cpu(inc->i_hdr.h_len); |
322 | |
323 | while (copied < size && copied < len) { |
324 | if (frag_off == RDS_FRAG_SIZE) { |
325 | frag = list_entry(frag->f_item.next, |
326 | struct rds_page_frag, f_item); |
327 | frag_off = 0; |
328 | } |
329 | while (iov_off == iov->iov_len) { |
330 | iov_off = 0; |
331 | iov++; |
332 | } |
333 | |
334 | to_copy = min(iov->iov_len - iov_off, RDS_FRAG_SIZE - frag_off); |
335 | to_copy = min_t(size_t, to_copy, size - copied); |
336 | to_copy = min_t(unsigned long, to_copy, len - copied); |
337 | |
338 | rdsdebug("%lu bytes to user [%p, %zu] + %lu from frag " |
339 | "[%p, %lu] + %lu\n", |
340 | to_copy, iov->iov_base, iov->iov_len, iov_off, |
341 | frag->f_page, frag->f_offset, frag_off); |
342 | |
343 | /* XXX needs + offset for multiple recvs per page */ |
344 | ret = rds_page_copy_to_user(frag->f_page, |
345 | frag->f_offset + frag_off, |
346 | iov->iov_base + iov_off, |
347 | to_copy); |
348 | if (ret) { |
349 | copied = ret; |
350 | break; |
351 | } |
352 | |
353 | iov_off += to_copy; |
354 | frag_off += to_copy; |
355 | copied += to_copy; |
356 | } |
357 | |
358 | return copied; |
359 | } |
360 | |
361 | /* ic starts out kzalloc()ed */ |
362 | void rds_ib_recv_init_ack(struct rds_ib_connection *ic) |
363 | { |
364 | struct ib_send_wr *wr = &ic->i_ack_wr; |
365 | struct ib_sge *sge = &ic->i_ack_sge; |
366 | |
367 | sge->addr = ic->i_ack_dma; |
368 | sge->length = sizeof(struct rds_header); |
369 | sge->lkey = ic->i_mr->lkey; |
370 | |
371 | wr->sg_list = sge; |
372 | wr->num_sge = 1; |
373 | wr->opcode = IB_WR_SEND; |
374 | wr->wr_id = RDS_IB_ACK_WR_ID; |
375 | wr->send_flags = IB_SEND_SIGNALED | IB_SEND_SOLICITED; |
376 | } |
377 | |
378 | /* |
379 | * You'd think that with reliable IB connections you wouldn't need to ack |
380 | * messages that have been received. The problem is that IB hardware generates |
381 | * an ack message before it has DMAed the message into memory. This creates a |
382 | * potential message loss if the HCA is disabled for any reason between when it |
383 | * sends the ack and before the message is DMAed and processed. This is only a |
384 | * potential issue if another HCA is available for fail-over. |
385 | * |
386 | * When the remote host receives our ack they'll free the sent message from |
387 | * their send queue. To decrease the latency of this we always send an ack |
388 | * immediately after we've received messages. |
389 | * |
390 | * For simplicity, we only have one ack in flight at a time. This puts |
391 | * pressure on senders to have deep enough send queues to absorb the latency of |
392 | * a single ack frame being in flight. This might not be good enough. |
393 | * |
394 | * This is implemented by have a long-lived send_wr and sge which point to a |
395 | * statically allocated ack frame. This ack wr does not fall under the ring |
396 | * accounting that the tx and rx wrs do. The QP attribute specifically makes |
397 | * room for it beyond the ring size. Send completion notices its special |
398 | * wr_id and avoids working with the ring in that case. |
399 | */ |
400 | #ifndef KERNEL_HAS_ATOMIC64 |
401 | static void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq, |
402 | int ack_required) |
403 | { |
404 | unsigned long flags; |
405 | |
406 | spin_lock_irqsave(&ic->i_ack_lock, flags); |
407 | ic->i_ack_next = seq; |
408 | if (ack_required) |
409 | set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); |
410 | spin_unlock_irqrestore(&ic->i_ack_lock, flags); |
411 | } |
412 | |
413 | static u64 rds_ib_get_ack(struct rds_ib_connection *ic) |
414 | { |
415 | unsigned long flags; |
416 | u64 seq; |
417 | |
418 | clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); |
419 | |
420 | spin_lock_irqsave(&ic->i_ack_lock, flags); |
421 | seq = ic->i_ack_next; |
422 | spin_unlock_irqrestore(&ic->i_ack_lock, flags); |
423 | |
424 | return seq; |
425 | } |
426 | #else |
427 | static void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq, |
428 | int ack_required) |
429 | { |
430 | atomic64_set(&ic->i_ack_next, seq); |
431 | if (ack_required) { |
432 | smp_mb__before_clear_bit(); |
433 | set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); |
434 | } |
435 | } |
436 | |
437 | static u64 rds_ib_get_ack(struct rds_ib_connection *ic) |
438 | { |
439 | clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); |
440 | smp_mb__after_clear_bit(); |
441 | |
442 | return atomic64_read(&ic->i_ack_next); |
443 | } |
444 | #endif |
445 | |
446 | |
447 | static void rds_ib_send_ack(struct rds_ib_connection *ic, unsigned int adv_credits) |
448 | { |
449 | struct rds_header *hdr = ic->i_ack; |
450 | struct ib_send_wr *failed_wr; |
451 | u64 seq; |
452 | int ret; |
453 | |
454 | seq = rds_ib_get_ack(ic); |
455 | |
456 | rdsdebug("send_ack: ic %p ack %llu\n", ic, (unsigned long long) seq); |
457 | rds_message_populate_header(hdr, 0, 0, 0); |
458 | hdr->h_ack = cpu_to_be64(seq); |
459 | hdr->h_credit = adv_credits; |
460 | rds_message_make_checksum(hdr); |
461 | ic->i_ack_queued = jiffies; |
462 | |
463 | ret = ib_post_send(ic->i_cm_id->qp, &ic->i_ack_wr, &failed_wr); |
464 | if (unlikely(ret)) { |
465 | /* Failed to send. Release the WR, and |
466 | * force another ACK. |
467 | */ |
468 | clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags); |
469 | set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); |
470 | |
471 | rds_ib_stats_inc(s_ib_ack_send_failure); |
472 | /* Need to finesse this later. */ |
473 | BUG(); |
474 | } else |
475 | rds_ib_stats_inc(s_ib_ack_sent); |
476 | } |
477 | |
478 | /* |
479 | * There are 3 ways of getting acknowledgements to the peer: |
480 | * 1. We call rds_ib_attempt_ack from the recv completion handler |
481 | * to send an ACK-only frame. |
482 | * However, there can be only one such frame in the send queue |
483 | * at any time, so we may have to postpone it. |
484 | * 2. When another (data) packet is transmitted while there's |
485 | * an ACK in the queue, we piggyback the ACK sequence number |
486 | * on the data packet. |
487 | * 3. If the ACK WR is done sending, we get called from the |
488 | * send queue completion handler, and check whether there's |
489 | * another ACK pending (postponed because the WR was on the |
490 | * queue). If so, we transmit it. |
491 | * |
492 | * We maintain 2 variables: |
493 | * - i_ack_flags, which keeps track of whether the ACK WR |
494 | * is currently in the send queue or not (IB_ACK_IN_FLIGHT) |
495 | * - i_ack_next, which is the last sequence number we received |
496 | * |
497 | * Potentially, send queue and receive queue handlers can run concurrently. |
498 | * It would be nice to not have to use a spinlock to synchronize things, |
499 | * but the one problem that rules this out is that 64bit updates are |
500 | * not atomic on all platforms. Things would be a lot simpler if |
501 | * we had atomic64 or maybe cmpxchg64 everywhere. |
502 | * |
503 | * Reconnecting complicates this picture just slightly. When we |
504 | * reconnect, we may be seeing duplicate packets. The peer |
505 | * is retransmitting them, because it hasn't seen an ACK for |
506 | * them. It is important that we ACK these. |
507 | * |
508 | * ACK mitigation adds a header flag "ACK_REQUIRED"; any packet with |
509 | * this flag set *MUST* be acknowledged immediately. |
510 | */ |
511 | |
512 | /* |
513 | * When we get here, we're called from the recv queue handler. |
514 | * Check whether we ought to transmit an ACK. |
515 | */ |
516 | void rds_ib_attempt_ack(struct rds_ib_connection *ic) |
517 | { |
518 | unsigned int adv_credits; |
519 | |
520 | if (!test_bit(IB_ACK_REQUESTED, &ic->i_ack_flags)) |
521 | return; |
522 | |
523 | if (test_and_set_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags)) { |
524 | rds_ib_stats_inc(s_ib_ack_send_delayed); |
525 | return; |
526 | } |
527 | |
528 | /* Can we get a send credit? */ |
529 | if (!rds_ib_send_grab_credits(ic, 1, &adv_credits, 0, RDS_MAX_ADV_CREDIT)) { |
530 | rds_ib_stats_inc(s_ib_tx_throttle); |
531 | clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags); |
532 | return; |
533 | } |
534 | |
535 | clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); |
536 | rds_ib_send_ack(ic, adv_credits); |
537 | } |
538 | |
539 | /* |
540 | * We get here from the send completion handler, when the |
541 | * adapter tells us the ACK frame was sent. |
542 | */ |
543 | void rds_ib_ack_send_complete(struct rds_ib_connection *ic) |
544 | { |
545 | clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags); |
546 | rds_ib_attempt_ack(ic); |
547 | } |
548 | |
549 | /* |
550 | * This is called by the regular xmit code when it wants to piggyback |
551 | * an ACK on an outgoing frame. |
552 | */ |
553 | u64 rds_ib_piggyb_ack(struct rds_ib_connection *ic) |
554 | { |
555 | if (test_and_clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags)) |
556 | rds_ib_stats_inc(s_ib_ack_send_piggybacked); |
557 | return rds_ib_get_ack(ic); |
558 | } |
559 | |
560 | static struct rds_header *rds_ib_get_header(struct rds_connection *conn, |
561 | struct rds_ib_recv_work *recv, |
562 | u32 data_len) |
563 | { |
564 | struct rds_ib_connection *ic = conn->c_transport_data; |
565 | void *hdr_buff = &ic->i_recv_hdrs[recv - ic->i_recvs]; |
566 | void *addr; |
567 | u32 misplaced_hdr_bytes; |
568 | |
569 | /* |
570 | * Support header at the front (RDS 3.1+) as well as header-at-end. |
571 | * |
572 | * Cases: |
573 | * 1) header all in header buff (great!) |
574 | * 2) header all in data page (copy all to header buff) |
575 | * 3) header split across hdr buf + data page |
576 | * (move bit in hdr buff to end before copying other bit from data page) |
577 | */ |
578 | if (conn->c_version > RDS_PROTOCOL_3_0 || data_len == RDS_FRAG_SIZE) |
579 | return hdr_buff; |
580 | |
581 | if (data_len <= (RDS_FRAG_SIZE - sizeof(struct rds_header))) { |
582 | addr = kmap_atomic(recv->r_frag->f_page, KM_SOFTIRQ0); |
583 | memcpy(hdr_buff, |
584 | addr + recv->r_frag->f_offset + data_len, |
585 | sizeof(struct rds_header)); |
586 | kunmap_atomic(addr, KM_SOFTIRQ0); |
587 | return hdr_buff; |
588 | } |
589 | |
590 | misplaced_hdr_bytes = (sizeof(struct rds_header) - (RDS_FRAG_SIZE - data_len)); |
591 | |
592 | memmove(hdr_buff + misplaced_hdr_bytes, hdr_buff, misplaced_hdr_bytes); |
593 | |
594 | addr = kmap_atomic(recv->r_frag->f_page, KM_SOFTIRQ0); |
595 | memcpy(hdr_buff, addr + recv->r_frag->f_offset + data_len, |
596 | sizeof(struct rds_header) - misplaced_hdr_bytes); |
597 | kunmap_atomic(addr, KM_SOFTIRQ0); |
598 | return hdr_buff; |
599 | } |
600 | |
601 | /* |
602 | * It's kind of lame that we're copying from the posted receive pages into |
603 | * long-lived bitmaps. We could have posted the bitmaps and rdma written into |
604 | * them. But receiving new congestion bitmaps should be a *rare* event, so |
605 | * hopefully we won't need to invest that complexity in making it more |
606 | * efficient. By copying we can share a simpler core with TCP which has to |
607 | * copy. |
608 | */ |
609 | static void rds_ib_cong_recv(struct rds_connection *conn, |
610 | struct rds_ib_incoming *ibinc) |
611 | { |
612 | struct rds_cong_map *map; |
613 | unsigned int map_off; |
614 | unsigned int map_page; |
615 | struct rds_page_frag *frag; |
616 | unsigned long frag_off; |
617 | unsigned long to_copy; |
618 | unsigned long copied; |
619 | uint64_t uncongested = 0; |
620 | void *addr; |
621 | |
622 | /* catch completely corrupt packets */ |
623 | if (be32_to_cpu(ibinc->ii_inc.i_hdr.h_len) != RDS_CONG_MAP_BYTES) |
624 | return; |
625 | |
626 | map = conn->c_fcong; |
627 | map_page = 0; |
628 | map_off = 0; |
629 | |
630 | frag = list_entry(ibinc->ii_frags.next, struct rds_page_frag, f_item); |
631 | frag_off = 0; |
632 | |
633 | copied = 0; |
634 | |
635 | while (copied < RDS_CONG_MAP_BYTES) { |
636 | uint64_t *src, *dst; |
637 | unsigned int k; |
638 | |
639 | to_copy = min(RDS_FRAG_SIZE - frag_off, PAGE_SIZE - map_off); |
640 | BUG_ON(to_copy & 7); /* Must be 64bit aligned. */ |
641 | |
642 | addr = kmap_atomic(frag->f_page, KM_SOFTIRQ0); |
643 | |
644 | src = addr + frag_off; |
645 | dst = (void *)map->m_page_addrs[map_page] + map_off; |
646 | for (k = 0; k < to_copy; k += 8) { |
647 | /* Record ports that became uncongested, ie |
648 | * bits that changed from 0 to 1. */ |
649 | uncongested |= ~(*src) & *dst; |
650 | *dst++ = *src++; |
651 | } |
652 | kunmap_atomic(addr, KM_SOFTIRQ0); |
653 | |
654 | copied += to_copy; |
655 | |
656 | map_off += to_copy; |
657 | if (map_off == PAGE_SIZE) { |
658 | map_off = 0; |
659 | map_page++; |
660 | } |
661 | |
662 | frag_off += to_copy; |
663 | if (frag_off == RDS_FRAG_SIZE) { |
664 | frag = list_entry(frag->f_item.next, |
665 | struct rds_page_frag, f_item); |
666 | frag_off = 0; |
667 | } |
668 | } |
669 | |
670 | /* the congestion map is in little endian order */ |
671 | uncongested = le64_to_cpu(uncongested); |
672 | |
673 | rds_cong_map_updated(map, uncongested); |
674 | } |
675 | |
676 | /* |
677 | * Rings are posted with all the allocations they'll need to queue the |
678 | * incoming message to the receiving socket so this can't fail. |
679 | * All fragments start with a header, so we can make sure we're not receiving |
680 | * garbage, and we can tell a small 8 byte fragment from an ACK frame. |
681 | */ |
682 | struct rds_ib_ack_state { |
683 | u64 ack_next; |
684 | u64 ack_recv; |
685 | unsigned int ack_required:1; |
686 | unsigned int ack_next_valid:1; |
687 | unsigned int ack_recv_valid:1; |
688 | }; |
689 | |
690 | static void rds_ib_process_recv(struct rds_connection *conn, |
691 | struct rds_ib_recv_work *recv, u32 data_len, |
692 | struct rds_ib_ack_state *state) |
693 | { |
694 | struct rds_ib_connection *ic = conn->c_transport_data; |
695 | struct rds_ib_incoming *ibinc = ic->i_ibinc; |
696 | struct rds_header *ihdr, *hdr; |
697 | |
698 | /* XXX shut down the connection if port 0,0 are seen? */ |
699 | |
700 | rdsdebug("ic %p ibinc %p recv %p byte len %u\n", ic, ibinc, recv, |
701 | data_len); |
702 | |
703 | if (data_len < sizeof(struct rds_header)) { |
704 | rds_ib_conn_error(conn, "incoming message " |
705 | "from %pI4 didn't inclue a " |
706 | "header, disconnecting and " |
707 | "reconnecting\n", |
708 | &conn->c_faddr); |
709 | return; |
710 | } |
711 | data_len -= sizeof(struct rds_header); |
712 | |
713 | ihdr = rds_ib_get_header(conn, recv, data_len); |
714 | |
715 | /* Validate the checksum. */ |
716 | if (!rds_message_verify_checksum(ihdr)) { |
717 | rds_ib_conn_error(conn, "incoming message " |
718 | "from %pI4 has corrupted header - " |
719 | "forcing a reconnect\n", |
720 | &conn->c_faddr); |
721 | rds_stats_inc(s_recv_drop_bad_checksum); |
722 | return; |
723 | } |
724 | |
725 | /* Process the ACK sequence which comes with every packet */ |
726 | state->ack_recv = be64_to_cpu(ihdr->h_ack); |
727 | state->ack_recv_valid = 1; |
728 | |
729 | /* Process the credits update if there was one */ |
730 | if (ihdr->h_credit) |
731 | rds_ib_send_add_credits(conn, ihdr->h_credit); |
732 | |
733 | if (ihdr->h_sport == 0 && ihdr->h_dport == 0 && data_len == 0) { |
734 | /* This is an ACK-only packet. The fact that it gets |
735 | * special treatment here is that historically, ACKs |
736 | * were rather special beasts. |
737 | */ |
738 | rds_ib_stats_inc(s_ib_ack_received); |
739 | |
740 | /* |
741 | * Usually the frags make their way on to incs and are then freed as |
742 | * the inc is freed. We don't go that route, so we have to drop the |
743 | * page ref ourselves. We can't just leave the page on the recv |
744 | * because that confuses the dma mapping of pages and each recv's use |
745 | * of a partial page. We can leave the frag, though, it will be |
746 | * reused. |
747 | * |
748 | * FIXME: Fold this into the code path below. |
749 | */ |
750 | rds_ib_frag_drop_page(recv->r_frag); |
751 | return; |
752 | } |
753 | |
754 | /* |
755 | * If we don't already have an inc on the connection then this |
756 | * fragment has a header and starts a message.. copy its header |
757 | * into the inc and save the inc so we can hang upcoming fragments |
758 | * off its list. |
759 | */ |
760 | if (ibinc == NULL) { |
761 | ibinc = recv->r_ibinc; |
762 | recv->r_ibinc = NULL; |
763 | ic->i_ibinc = ibinc; |
764 | |
765 | hdr = &ibinc->ii_inc.i_hdr; |
766 | memcpy(hdr, ihdr, sizeof(*hdr)); |
767 | ic->i_recv_data_rem = be32_to_cpu(hdr->h_len); |
768 | |
769 | rdsdebug("ic %p ibinc %p rem %u flag 0x%x\n", ic, ibinc, |
770 | ic->i_recv_data_rem, hdr->h_flags); |
771 | } else { |
772 | hdr = &ibinc->ii_inc.i_hdr; |
773 | /* We can't just use memcmp here; fragments of a |
774 | * single message may carry different ACKs */ |
775 | if (hdr->h_sequence != ihdr->h_sequence || |
776 | hdr->h_len != ihdr->h_len || |
777 | hdr->h_sport != ihdr->h_sport || |
778 | hdr->h_dport != ihdr->h_dport) { |
779 | rds_ib_conn_error(conn, |
780 | "fragment header mismatch; forcing reconnect\n"); |
781 | return; |
782 | } |
783 | } |
784 | |
785 | list_add_tail(&recv->r_frag->f_item, &ibinc->ii_frags); |
786 | recv->r_frag = NULL; |
787 | |
788 | if (ic->i_recv_data_rem > RDS_FRAG_SIZE) |
789 | ic->i_recv_data_rem -= RDS_FRAG_SIZE; |
790 | else { |
791 | ic->i_recv_data_rem = 0; |
792 | ic->i_ibinc = NULL; |
793 | |
794 | if (ibinc->ii_inc.i_hdr.h_flags == RDS_FLAG_CONG_BITMAP) |
795 | rds_ib_cong_recv(conn, ibinc); |
796 | else { |
797 | rds_recv_incoming(conn, conn->c_faddr, conn->c_laddr, |
798 | &ibinc->ii_inc, GFP_ATOMIC, |
799 | KM_SOFTIRQ0); |
800 | state->ack_next = be64_to_cpu(hdr->h_sequence); |
801 | state->ack_next_valid = 1; |
802 | } |
803 | |
804 | /* Evaluate the ACK_REQUIRED flag *after* we received |
805 | * the complete frame, and after bumping the next_rx |
806 | * sequence. */ |
807 | if (hdr->h_flags & RDS_FLAG_ACK_REQUIRED) { |
808 | rds_stats_inc(s_recv_ack_required); |
809 | state->ack_required = 1; |
810 | } |
811 | |
812 | rds_inc_put(&ibinc->ii_inc); |
813 | } |
814 | } |
815 | |
816 | /* |
817 | * Plucking the oldest entry from the ring can be done concurrently with |
818 | * the thread refilling the ring. Each ring operation is protected by |
819 | * spinlocks and the transient state of refilling doesn't change the |
820 | * recording of which entry is oldest. |
821 | * |
822 | * This relies on IB only calling one cq comp_handler for each cq so that |
823 | * there will only be one caller of rds_recv_incoming() per RDS connection. |
824 | */ |
825 | void rds_ib_recv_cq_comp_handler(struct ib_cq *cq, void *context) |
826 | { |
827 | struct rds_connection *conn = context; |
828 | struct rds_ib_connection *ic = conn->c_transport_data; |
829 | |
830 | rdsdebug("conn %p cq %p\n", conn, cq); |
831 | |
832 | rds_ib_stats_inc(s_ib_rx_cq_call); |
833 | |
834 | tasklet_schedule(&ic->i_recv_tasklet); |
835 | } |
836 | |
837 | static inline void rds_poll_cq(struct rds_ib_connection *ic, |
838 | struct rds_ib_ack_state *state) |
839 | { |
840 | struct rds_connection *conn = ic->conn; |
841 | struct ib_wc wc; |
842 | struct rds_ib_recv_work *recv; |
843 | |
844 | while (ib_poll_cq(ic->i_recv_cq, 1, &wc) > 0) { |
845 | rdsdebug("wc wr_id 0x%llx status %u byte_len %u imm_data %u\n", |
846 | (unsigned long long)wc.wr_id, wc.status, wc.byte_len, |
847 | be32_to_cpu(wc.ex.imm_data)); |
848 | rds_ib_stats_inc(s_ib_rx_cq_event); |
849 | |
850 | recv = &ic->i_recvs[rds_ib_ring_oldest(&ic->i_recv_ring)]; |
851 | |
852 | rds_ib_recv_unmap_page(ic, recv); |
853 | |
854 | /* |
855 | * Also process recvs in connecting state because it is possible |
856 | * to get a recv completion _before_ the rdmacm ESTABLISHED |
857 | * event is processed. |
858 | */ |
859 | if (rds_conn_up(conn) || rds_conn_connecting(conn)) { |
860 | /* We expect errors as the qp is drained during shutdown */ |
861 | if (wc.status == IB_WC_SUCCESS) { |
862 | rds_ib_process_recv(conn, recv, wc.byte_len, state); |
863 | } else { |
864 | rds_ib_conn_error(conn, "recv completion on " |
865 | "%pI4 had status %u, disconnecting and " |
866 | "reconnecting\n", &conn->c_faddr, |
867 | wc.status); |
868 | } |
869 | } |
870 | |
871 | rds_ib_ring_free(&ic->i_recv_ring, 1); |
872 | } |
873 | } |
874 | |
875 | void rds_ib_recv_tasklet_fn(unsigned long data) |
876 | { |
877 | struct rds_ib_connection *ic = (struct rds_ib_connection *) data; |
878 | struct rds_connection *conn = ic->conn; |
879 | struct rds_ib_ack_state state = { 0, }; |
880 | |
881 | rds_poll_cq(ic, &state); |
882 | ib_req_notify_cq(ic->i_recv_cq, IB_CQ_SOLICITED); |
883 | rds_poll_cq(ic, &state); |
884 | |
885 | if (state.ack_next_valid) |
886 | rds_ib_set_ack(ic, state.ack_next, state.ack_required); |
887 | if (state.ack_recv_valid && state.ack_recv > ic->i_ack_recv) { |
888 | rds_send_drop_acked(conn, state.ack_recv, NULL); |
889 | ic->i_ack_recv = state.ack_recv; |
890 | } |
891 | if (rds_conn_up(conn)) |
892 | rds_ib_attempt_ack(ic); |
893 | |
894 | /* If we ever end up with a really empty receive ring, we're |
895 | * in deep trouble, as the sender will definitely see RNR |
896 | * timeouts. */ |
897 | if (rds_ib_ring_empty(&ic->i_recv_ring)) |
898 | rds_ib_stats_inc(s_ib_rx_ring_empty); |
899 | |
900 | /* |
901 | * If the ring is running low, then schedule the thread to refill. |
902 | */ |
903 | if (rds_ib_ring_low(&ic->i_recv_ring)) |
904 | queue_delayed_work(rds_wq, &conn->c_recv_w, 0); |
905 | } |
906 | |
907 | int rds_ib_recv(struct rds_connection *conn) |
908 | { |
909 | struct rds_ib_connection *ic = conn->c_transport_data; |
910 | int ret = 0; |
911 | |
912 | rdsdebug("conn %p\n", conn); |
913 | |
914 | /* |
915 | * If we get a temporary posting failure in this context then |
916 | * we're really low and we want the caller to back off for a bit. |
917 | */ |
918 | mutex_lock(&ic->i_recv_mutex); |
919 | if (rds_ib_recv_refill(conn, GFP_KERNEL, GFP_HIGHUSER, 0)) |
920 | ret = -ENOMEM; |
921 | else |
922 | rds_ib_stats_inc(s_ib_rx_refill_from_thread); |
923 | mutex_unlock(&ic->i_recv_mutex); |
924 | |
925 | if (rds_conn_up(conn)) |
926 | rds_ib_attempt_ack(ic); |
927 | |
928 | return ret; |
929 | } |
930 | |
931 | int __init rds_ib_recv_init(void) |
932 | { |
933 | struct sysinfo si; |
934 | int ret = -ENOMEM; |
935 | |
936 | /* Default to 30% of all available RAM for recv memory */ |
937 | si_meminfo(&si); |
938 | rds_ib_sysctl_max_recv_allocation = si.totalram / 3 * PAGE_SIZE / RDS_FRAG_SIZE; |
939 | |
940 | rds_ib_incoming_slab = kmem_cache_create("rds_ib_incoming", |
941 | sizeof(struct rds_ib_incoming), |
942 | 0, 0, NULL); |
943 | if (rds_ib_incoming_slab == NULL) |
944 | goto out; |
945 | |
946 | rds_ib_frag_slab = kmem_cache_create("rds_ib_frag", |
947 | sizeof(struct rds_page_frag), |
948 | 0, 0, NULL); |
949 | if (rds_ib_frag_slab == NULL) |
950 | kmem_cache_destroy(rds_ib_incoming_slab); |
951 | else |
952 | ret = 0; |
953 | out: |
954 | return ret; |
955 | } |
956 | |
957 | void rds_ib_recv_exit(void) |
958 | { |
959 | kmem_cache_destroy(rds_ib_incoming_slab); |
960 | kmem_cache_destroy(rds_ib_frag_slab); |
961 | } |
962 |
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