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1e23b3ee AG |
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/pci.h> | |
35 | #include <linux/dma-mapping.h> | |
36 | #include <rdma/rdma_cm.h> | |
37 | ||
38 | #include "rds.h" | |
39 | #include "ib.h" | |
40 | ||
41 | static struct kmem_cache *rds_ib_incoming_slab; | |
42 | static struct kmem_cache *rds_ib_frag_slab; | |
43 | static atomic_t rds_ib_allocation = ATOMIC_INIT(0); | |
44 | ||
45 | static 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 | ||
52 | static 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 | */ | |
68 | static 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 | ||
81 | void 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 | ||
109 | static 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 | ||
125 | void 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 | ||
136 | static 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) { | |
86357b19 | 146 | if (!atomic_add_unless(&rds_ib_allocation, 1, rds_ib_sysctl_max_recv_allocation)) { |
1e23b3ee AG |
147 | 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); | |
86357b19 AG |
152 | if (recv->r_ibinc == NULL) { |
153 | atomic_dec(&rds_ib_allocation); | |
1e23b3ee | 154 | goto out; |
86357b19 | 155 | } |
1e23b3ee AG |
156 | 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; | |
211 | out: | |
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 | */ | |
223 | int 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 | ||
f64f9e71 JP |
233 | while ((prefill || rds_conn_up(conn)) && |
234 | rds_ib_ring_alloc(&ic->i_recv_ring, 1, &pos)) { | |
1e23b3ee AG |
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 | ||
275 | void 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 | ||
291 | void 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 | ||
305 | int 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 */ | |
361 | void 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 | */ | |
8cbd9606 | 399 | #ifndef KERNEL_HAS_ATOMIC64 |
1e23b3ee AG |
400 | static void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq, |
401 | int ack_required) | |
402 | { | |
8cbd9606 AG |
403 | 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 | ||
412 | static 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 | |
426 | static 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); | |
1e23b3ee AG |
430 | if (ack_required) { |
431 | smp_mb__before_clear_bit(); | |
432 | set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); | |
433 | } | |
434 | } | |
435 | ||
436 | static 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 | ||
8cbd9606 | 441 | return atomic64_read(&ic->i_ack_next); |
1e23b3ee | 442 | } |
8cbd9606 AG |
443 | #endif |
444 | ||
1e23b3ee AG |
445 | |
446 | static 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. | |
8cbd9606 AG |
497 | * 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. | |
1e23b3ee AG |
501 | * |
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 | */ | |
515 | void 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? */ | |
7b70d033 | 528 | if (!rds_ib_send_grab_credits(ic, 1, &adv_credits, 0, RDS_MAX_ADV_CREDIT)) { |
1e23b3ee AG |
529 | 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 | */ | |
542 | void 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 | */ | |
552 | u64 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 | ||
02a6a259 AG |
559 | static 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 | ||
1e23b3ee AG |
600 | /* |
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 | */ | |
608 | static 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 | */ | |
681 | struct 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 | ||
689 | static void rds_ib_process_recv(struct rds_connection *conn, | |
597ddd50 | 690 | struct rds_ib_recv_work *recv, u32 data_len, |
1e23b3ee AG |
691 | 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, | |
597ddd50 | 700 | data_len); |
1e23b3ee | 701 | |
597ddd50 | 702 | if (data_len < sizeof(struct rds_header)) { |
1e23b3ee AG |
703 | 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 | } | |
597ddd50 | 710 | data_len -= sizeof(struct rds_header); |
1e23b3ee | 711 | |
597ddd50 | 712 | ihdr = rds_ib_get_header(conn, recv, data_len); |
1e23b3ee AG |
713 | |
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 | ||
597ddd50 | 732 | if (ihdr->h_sport == 0 && ihdr->h_dport == 0 && data_len == 0) { |
1e23b3ee AG |
733 | /* 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 */ | |
f64f9e71 JP |
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) { | |
1e23b3ee AG |
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 | */ | |
824 | void 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; | |
1e23b3ee AG |
828 | |
829 | rdsdebug("conn %p cq %p\n", conn, cq); | |
830 | ||
831 | rds_ib_stats_inc(s_ib_rx_cq_call); | |
832 | ||
d521b63b AG |
833 | tasklet_schedule(&ic->i_recv_tasklet); |
834 | } | |
1e23b3ee | 835 | |
d521b63b AG |
836 | static inline void rds_poll_cq(struct rds_ib_connection *ic, |
837 | struct rds_ib_ack_state *state) | |
838 | { | |
839 | struct rds_connection *conn = ic->conn; | |
840 | struct ib_wc wc; | |
841 | struct rds_ib_recv_work *recv; | |
842 | ||
843 | while (ib_poll_cq(ic->i_recv_cq, 1, &wc) > 0) { | |
1e23b3ee AG |
844 | rdsdebug("wc wr_id 0x%llx status %u byte_len %u imm_data %u\n", |
845 | (unsigned long long)wc.wr_id, wc.status, wc.byte_len, | |
846 | be32_to_cpu(wc.ex.imm_data)); | |
847 | rds_ib_stats_inc(s_ib_rx_cq_event); | |
848 | ||
849 | recv = &ic->i_recvs[rds_ib_ring_oldest(&ic->i_recv_ring)]; | |
850 | ||
851 | rds_ib_recv_unmap_page(ic, recv); | |
852 | ||
853 | /* | |
854 | * Also process recvs in connecting state because it is possible | |
855 | * to get a recv completion _before_ the rdmacm ESTABLISHED | |
856 | * event is processed. | |
857 | */ | |
858 | if (rds_conn_up(conn) || rds_conn_connecting(conn)) { | |
859 | /* We expect errors as the qp is drained during shutdown */ | |
860 | if (wc.status == IB_WC_SUCCESS) { | |
d521b63b | 861 | rds_ib_process_recv(conn, recv, wc.byte_len, state); |
1e23b3ee AG |
862 | } else { |
863 | rds_ib_conn_error(conn, "recv completion on " | |
864 | "%pI4 had status %u, disconnecting and " | |
865 | "reconnecting\n", &conn->c_faddr, | |
866 | wc.status); | |
867 | } | |
868 | } | |
869 | ||
870 | rds_ib_ring_free(&ic->i_recv_ring, 1); | |
871 | } | |
d521b63b AG |
872 | } |
873 | ||
874 | void rds_ib_recv_tasklet_fn(unsigned long data) | |
875 | { | |
876 | struct rds_ib_connection *ic = (struct rds_ib_connection *) data; | |
877 | struct rds_connection *conn = ic->conn; | |
878 | struct rds_ib_ack_state state = { 0, }; | |
879 | ||
880 | rds_poll_cq(ic, &state); | |
881 | ib_req_notify_cq(ic->i_recv_cq, IB_CQ_SOLICITED); | |
882 | rds_poll_cq(ic, &state); | |
1e23b3ee AG |
883 | |
884 | if (state.ack_next_valid) | |
885 | rds_ib_set_ack(ic, state.ack_next, state.ack_required); | |
886 | if (state.ack_recv_valid && state.ack_recv > ic->i_ack_recv) { | |
887 | rds_send_drop_acked(conn, state.ack_recv, NULL); | |
888 | ic->i_ack_recv = state.ack_recv; | |
889 | } | |
890 | if (rds_conn_up(conn)) | |
891 | rds_ib_attempt_ack(ic); | |
892 | ||
893 | /* If we ever end up with a really empty receive ring, we're | |
894 | * in deep trouble, as the sender will definitely see RNR | |
895 | * timeouts. */ | |
896 | if (rds_ib_ring_empty(&ic->i_recv_ring)) | |
897 | rds_ib_stats_inc(s_ib_rx_ring_empty); | |
898 | ||
899 | /* | |
900 | * If the ring is running low, then schedule the thread to refill. | |
901 | */ | |
902 | if (rds_ib_ring_low(&ic->i_recv_ring)) | |
903 | queue_delayed_work(rds_wq, &conn->c_recv_w, 0); | |
904 | } | |
905 | ||
906 | int rds_ib_recv(struct rds_connection *conn) | |
907 | { | |
908 | struct rds_ib_connection *ic = conn->c_transport_data; | |
909 | int ret = 0; | |
910 | ||
911 | rdsdebug("conn %p\n", conn); | |
912 | ||
913 | /* | |
914 | * If we get a temporary posting failure in this context then | |
915 | * we're really low and we want the caller to back off for a bit. | |
916 | */ | |
917 | mutex_lock(&ic->i_recv_mutex); | |
918 | if (rds_ib_recv_refill(conn, GFP_KERNEL, GFP_HIGHUSER, 0)) | |
919 | ret = -ENOMEM; | |
920 | else | |
921 | rds_ib_stats_inc(s_ib_rx_refill_from_thread); | |
922 | mutex_unlock(&ic->i_recv_mutex); | |
923 | ||
924 | if (rds_conn_up(conn)) | |
925 | rds_ib_attempt_ack(ic); | |
926 | ||
927 | return ret; | |
928 | } | |
929 | ||
930 | int __init rds_ib_recv_init(void) | |
931 | { | |
932 | struct sysinfo si; | |
933 | int ret = -ENOMEM; | |
934 | ||
935 | /* Default to 30% of all available RAM for recv memory */ | |
936 | si_meminfo(&si); | |
937 | rds_ib_sysctl_max_recv_allocation = si.totalram / 3 * PAGE_SIZE / RDS_FRAG_SIZE; | |
938 | ||
939 | rds_ib_incoming_slab = kmem_cache_create("rds_ib_incoming", | |
940 | sizeof(struct rds_ib_incoming), | |
941 | 0, 0, NULL); | |
942 | if (rds_ib_incoming_slab == NULL) | |
943 | goto out; | |
944 | ||
945 | rds_ib_frag_slab = kmem_cache_create("rds_ib_frag", | |
946 | sizeof(struct rds_page_frag), | |
947 | 0, 0, NULL); | |
948 | if (rds_ib_frag_slab == NULL) | |
949 | kmem_cache_destroy(rds_ib_incoming_slab); | |
950 | else | |
951 | ret = 0; | |
952 | out: | |
953 | return ret; | |
954 | } | |
955 | ||
956 | void rds_ib_recv_exit(void) | |
957 | { | |
958 | kmem_cache_destroy(rds_ib_incoming_slab); | |
959 | kmem_cache_destroy(rds_ib_frag_slab); | |
960 | } |