Root/
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 "iw.h" |
41 | |
42 | static struct kmem_cache *rds_iw_incoming_slab; |
43 | static struct kmem_cache *rds_iw_frag_slab; |
44 | static atomic_t rds_iw_allocation = ATOMIC_INIT(0); |
45 | |
46 | static void rds_iw_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_iw_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_iw_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_iw_recv_unmap_page(struct rds_iw_connection *ic, |
70 | struct rds_iw_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_iw_recv_init_ring(struct rds_iw_connection *ic) |
83 | { |
84 | struct rds_iw_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_iwinc = 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_IW_RECV_SGE; |
97 | |
98 | sge = rds_iw_data_sge(ic, recv->r_sge); |
99 | sge->addr = 0; |
100 | sge->length = RDS_FRAG_SIZE; |
101 | sge->lkey = 0; |
102 | |
103 | sge = rds_iw_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 = 0; |
107 | } |
108 | } |
109 | |
110 | static void rds_iw_recv_clear_one(struct rds_iw_connection *ic, |
111 | struct rds_iw_recv_work *recv) |
112 | { |
113 | if (recv->r_iwinc) { |
114 | rds_inc_put(&recv->r_iwinc->ii_inc); |
115 | recv->r_iwinc = NULL; |
116 | } |
117 | if (recv->r_frag) { |
118 | rds_iw_recv_unmap_page(ic, recv); |
119 | if (recv->r_frag->f_page) |
120 | rds_iw_frag_drop_page(recv->r_frag); |
121 | rds_iw_frag_free(recv->r_frag); |
122 | recv->r_frag = NULL; |
123 | } |
124 | } |
125 | |
126 | void rds_iw_recv_clear_ring(struct rds_iw_connection *ic) |
127 | { |
128 | u32 i; |
129 | |
130 | for (i = 0; i < ic->i_recv_ring.w_nr; i++) |
131 | rds_iw_recv_clear_one(ic, &ic->i_recvs[i]); |
132 | |
133 | if (ic->i_frag.f_page) |
134 | rds_iw_frag_drop_page(&ic->i_frag); |
135 | } |
136 | |
137 | static int rds_iw_recv_refill_one(struct rds_connection *conn, |
138 | struct rds_iw_recv_work *recv, |
139 | gfp_t kptr_gfp, gfp_t page_gfp) |
140 | { |
141 | struct rds_iw_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_iwinc == NULL) { |
147 | if (!atomic_add_unless(&rds_iw_allocation, 1, rds_iw_sysctl_max_recv_allocation)) { |
148 | rds_iw_stats_inc(s_iw_rx_alloc_limit); |
149 | goto out; |
150 | } |
151 | recv->r_iwinc = kmem_cache_alloc(rds_iw_incoming_slab, |
152 | kptr_gfp); |
153 | if (recv->r_iwinc == NULL) { |
154 | atomic_dec(&rds_iw_allocation); |
155 | goto out; |
156 | } |
157 | INIT_LIST_HEAD(&recv->r_iwinc->ii_frags); |
158 | rds_inc_init(&recv->r_iwinc->ii_inc, conn, conn->c_faddr); |
159 | } |
160 | |
161 | if (recv->r_frag == NULL) { |
162 | recv->r_frag = kmem_cache_alloc(rds_iw_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_iw_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_iw_data_sge(ic, recv->r_sge); |
194 | sge->addr = dma_addr; |
195 | sge->length = RDS_FRAG_SIZE; |
196 | |
197 | sge = rds_iw_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_iw_recv_refill(struct rds_connection *conn, gfp_t kptr_gfp, |
225 | gfp_t page_gfp, int prefill) |
226 | { |
227 | struct rds_iw_connection *ic = conn->c_transport_data; |
228 | struct rds_iw_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_iw_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_iw_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 iwinc %p page %p addr %lu ret %d\n", recv, |
253 | recv->r_iwinc, recv->r_frag->f_page, |
254 | (long) recv->r_frag->f_mapped, ret); |
255 | if (ret) { |
256 | rds_iw_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_iw_advertise_credits(conn, posted); |
270 | |
271 | if (ret) |
272 | rds_iw_ring_unalloc(&ic->i_recv_ring, 1); |
273 | return ret; |
274 | } |
275 | |
276 | void rds_iw_inc_purge(struct rds_incoming *inc) |
277 | { |
278 | struct rds_iw_incoming *iwinc; |
279 | struct rds_page_frag *frag; |
280 | struct rds_page_frag *pos; |
281 | |
282 | iwinc = container_of(inc, struct rds_iw_incoming, ii_inc); |
283 | rdsdebug("purging iwinc %p inc %p\n", iwinc, inc); |
284 | |
285 | list_for_each_entry_safe(frag, pos, &iwinc->ii_frags, f_item) { |
286 | list_del_init(&frag->f_item); |
287 | rds_iw_frag_drop_page(frag); |
288 | rds_iw_frag_free(frag); |
289 | } |
290 | } |
291 | |
292 | void rds_iw_inc_free(struct rds_incoming *inc) |
293 | { |
294 | struct rds_iw_incoming *iwinc; |
295 | |
296 | iwinc = container_of(inc, struct rds_iw_incoming, ii_inc); |
297 | |
298 | rds_iw_inc_purge(inc); |
299 | rdsdebug("freeing iwinc %p inc %p\n", iwinc, inc); |
300 | BUG_ON(!list_empty(&iwinc->ii_frags)); |
301 | kmem_cache_free(rds_iw_incoming_slab, iwinc); |
302 | atomic_dec(&rds_iw_allocation); |
303 | BUG_ON(atomic_read(&rds_iw_allocation) < 0); |
304 | } |
305 | |
306 | int rds_iw_inc_copy_to_user(struct rds_incoming *inc, struct iovec *first_iov, |
307 | size_t size) |
308 | { |
309 | struct rds_iw_incoming *iwinc; |
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 | iwinc = container_of(inc, struct rds_iw_incoming, ii_inc); |
320 | frag = list_entry(iwinc->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_iw_recv_init_ack(struct rds_iw_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 = rds_iw_local_dma_lkey(ic); |
370 | |
371 | wr->sg_list = sge; |
372 | wr->num_sge = 1; |
373 | wr->opcode = IB_WR_SEND; |
374 | wr->wr_id = RDS_IW_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_iw_set_ack(struct rds_iw_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_iw_get_ack(struct rds_iw_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_iw_set_ack(struct rds_iw_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_iw_get_ack(struct rds_iw_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_iw_send_ack(struct rds_iw_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_iw_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_iw_stats_inc(s_iw_ack_send_failure); |
472 | /* Need to finesse this later. */ |
473 | BUG(); |
474 | } else |
475 | rds_iw_stats_inc(s_iw_ack_sent); |
476 | } |
477 | |
478 | /* |
479 | * There are 3 ways of getting acknowledgements to the peer: |
480 | * 1. We call rds_iw_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_iw_attempt_ack(struct rds_iw_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_iw_stats_inc(s_iw_ack_send_delayed); |
525 | return; |
526 | } |
527 | |
528 | /* Can we get a send credit? */ |
529 | if (!rds_iw_send_grab_credits(ic, 1, &adv_credits, 0, RDS_MAX_ADV_CREDIT)) { |
530 | rds_iw_stats_inc(s_iw_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_iw_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_iw_ack_send_complete(struct rds_iw_connection *ic) |
544 | { |
545 | clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags); |
546 | rds_iw_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_iw_piggyb_ack(struct rds_iw_connection *ic) |
554 | { |
555 | if (test_and_clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags)) |
556 | rds_iw_stats_inc(s_iw_ack_send_piggybacked); |
557 | return rds_iw_get_ack(ic); |
558 | } |
559 | |
560 | /* |
561 | * It's kind of lame that we're copying from the posted receive pages into |
562 | * long-lived bitmaps. We could have posted the bitmaps and rdma written into |
563 | * them. But receiving new congestion bitmaps should be a *rare* event, so |
564 | * hopefully we won't need to invest that complexity in making it more |
565 | * efficient. By copying we can share a simpler core with TCP which has to |
566 | * copy. |
567 | */ |
568 | static void rds_iw_cong_recv(struct rds_connection *conn, |
569 | struct rds_iw_incoming *iwinc) |
570 | { |
571 | struct rds_cong_map *map; |
572 | unsigned int map_off; |
573 | unsigned int map_page; |
574 | struct rds_page_frag *frag; |
575 | unsigned long frag_off; |
576 | unsigned long to_copy; |
577 | unsigned long copied; |
578 | uint64_t uncongested = 0; |
579 | void *addr; |
580 | |
581 | /* catch completely corrupt packets */ |
582 | if (be32_to_cpu(iwinc->ii_inc.i_hdr.h_len) != RDS_CONG_MAP_BYTES) |
583 | return; |
584 | |
585 | map = conn->c_fcong; |
586 | map_page = 0; |
587 | map_off = 0; |
588 | |
589 | frag = list_entry(iwinc->ii_frags.next, struct rds_page_frag, f_item); |
590 | frag_off = 0; |
591 | |
592 | copied = 0; |
593 | |
594 | while (copied < RDS_CONG_MAP_BYTES) { |
595 | uint64_t *src, *dst; |
596 | unsigned int k; |
597 | |
598 | to_copy = min(RDS_FRAG_SIZE - frag_off, PAGE_SIZE - map_off); |
599 | BUG_ON(to_copy & 7); /* Must be 64bit aligned. */ |
600 | |
601 | addr = kmap_atomic(frag->f_page, KM_SOFTIRQ0); |
602 | |
603 | src = addr + frag_off; |
604 | dst = (void *)map->m_page_addrs[map_page] + map_off; |
605 | for (k = 0; k < to_copy; k += 8) { |
606 | /* Record ports that became uncongested, ie |
607 | * bits that changed from 0 to 1. */ |
608 | uncongested |= ~(*src) & *dst; |
609 | *dst++ = *src++; |
610 | } |
611 | kunmap_atomic(addr, KM_SOFTIRQ0); |
612 | |
613 | copied += to_copy; |
614 | |
615 | map_off += to_copy; |
616 | if (map_off == PAGE_SIZE) { |
617 | map_off = 0; |
618 | map_page++; |
619 | } |
620 | |
621 | frag_off += to_copy; |
622 | if (frag_off == RDS_FRAG_SIZE) { |
623 | frag = list_entry(frag->f_item.next, |
624 | struct rds_page_frag, f_item); |
625 | frag_off = 0; |
626 | } |
627 | } |
628 | |
629 | /* the congestion map is in little endian order */ |
630 | uncongested = le64_to_cpu(uncongested); |
631 | |
632 | rds_cong_map_updated(map, uncongested); |
633 | } |
634 | |
635 | /* |
636 | * Rings are posted with all the allocations they'll need to queue the |
637 | * incoming message to the receiving socket so this can't fail. |
638 | * All fragments start with a header, so we can make sure we're not receiving |
639 | * garbage, and we can tell a small 8 byte fragment from an ACK frame. |
640 | */ |
641 | struct rds_iw_ack_state { |
642 | u64 ack_next; |
643 | u64 ack_recv; |
644 | unsigned int ack_required:1; |
645 | unsigned int ack_next_valid:1; |
646 | unsigned int ack_recv_valid:1; |
647 | }; |
648 | |
649 | static void rds_iw_process_recv(struct rds_connection *conn, |
650 | struct rds_iw_recv_work *recv, u32 byte_len, |
651 | struct rds_iw_ack_state *state) |
652 | { |
653 | struct rds_iw_connection *ic = conn->c_transport_data; |
654 | struct rds_iw_incoming *iwinc = ic->i_iwinc; |
655 | struct rds_header *ihdr, *hdr; |
656 | |
657 | /* XXX shut down the connection if port 0,0 are seen? */ |
658 | |
659 | rdsdebug("ic %p iwinc %p recv %p byte len %u\n", ic, iwinc, recv, |
660 | byte_len); |
661 | |
662 | if (byte_len < sizeof(struct rds_header)) { |
663 | rds_iw_conn_error(conn, "incoming message " |
664 | "from %pI4 didn't inclue a " |
665 | "header, disconnecting and " |
666 | "reconnecting\n", |
667 | &conn->c_faddr); |
668 | return; |
669 | } |
670 | byte_len -= sizeof(struct rds_header); |
671 | |
672 | ihdr = &ic->i_recv_hdrs[recv - ic->i_recvs]; |
673 | |
674 | /* Validate the checksum. */ |
675 | if (!rds_message_verify_checksum(ihdr)) { |
676 | rds_iw_conn_error(conn, "incoming message " |
677 | "from %pI4 has corrupted header - " |
678 | "forcing a reconnect\n", |
679 | &conn->c_faddr); |
680 | rds_stats_inc(s_recv_drop_bad_checksum); |
681 | return; |
682 | } |
683 | |
684 | /* Process the ACK sequence which comes with every packet */ |
685 | state->ack_recv = be64_to_cpu(ihdr->h_ack); |
686 | state->ack_recv_valid = 1; |
687 | |
688 | /* Process the credits update if there was one */ |
689 | if (ihdr->h_credit) |
690 | rds_iw_send_add_credits(conn, ihdr->h_credit); |
691 | |
692 | if (ihdr->h_sport == 0 && ihdr->h_dport == 0 && byte_len == 0) { |
693 | /* This is an ACK-only packet. The fact that it gets |
694 | * special treatment here is that historically, ACKs |
695 | * were rather special beasts. |
696 | */ |
697 | rds_iw_stats_inc(s_iw_ack_received); |
698 | |
699 | /* |
700 | * Usually the frags make their way on to incs and are then freed as |
701 | * the inc is freed. We don't go that route, so we have to drop the |
702 | * page ref ourselves. We can't just leave the page on the recv |
703 | * because that confuses the dma mapping of pages and each recv's use |
704 | * of a partial page. We can leave the frag, though, it will be |
705 | * reused. |
706 | * |
707 | * FIXME: Fold this into the code path below. |
708 | */ |
709 | rds_iw_frag_drop_page(recv->r_frag); |
710 | return; |
711 | } |
712 | |
713 | /* |
714 | * If we don't already have an inc on the connection then this |
715 | * fragment has a header and starts a message.. copy its header |
716 | * into the inc and save the inc so we can hang upcoming fragments |
717 | * off its list. |
718 | */ |
719 | if (iwinc == NULL) { |
720 | iwinc = recv->r_iwinc; |
721 | recv->r_iwinc = NULL; |
722 | ic->i_iwinc = iwinc; |
723 | |
724 | hdr = &iwinc->ii_inc.i_hdr; |
725 | memcpy(hdr, ihdr, sizeof(*hdr)); |
726 | ic->i_recv_data_rem = be32_to_cpu(hdr->h_len); |
727 | |
728 | rdsdebug("ic %p iwinc %p rem %u flag 0x%x\n", ic, iwinc, |
729 | ic->i_recv_data_rem, hdr->h_flags); |
730 | } else { |
731 | hdr = &iwinc->ii_inc.i_hdr; |
732 | /* We can't just use memcmp here; fragments of a |
733 | * single message may carry different ACKs */ |
734 | if (hdr->h_sequence != ihdr->h_sequence || |
735 | hdr->h_len != ihdr->h_len || |
736 | hdr->h_sport != ihdr->h_sport || |
737 | hdr->h_dport != ihdr->h_dport) { |
738 | rds_iw_conn_error(conn, |
739 | "fragment header mismatch; forcing reconnect\n"); |
740 | return; |
741 | } |
742 | } |
743 | |
744 | list_add_tail(&recv->r_frag->f_item, &iwinc->ii_frags); |
745 | recv->r_frag = NULL; |
746 | |
747 | if (ic->i_recv_data_rem > RDS_FRAG_SIZE) |
748 | ic->i_recv_data_rem -= RDS_FRAG_SIZE; |
749 | else { |
750 | ic->i_recv_data_rem = 0; |
751 | ic->i_iwinc = NULL; |
752 | |
753 | if (iwinc->ii_inc.i_hdr.h_flags == RDS_FLAG_CONG_BITMAP) |
754 | rds_iw_cong_recv(conn, iwinc); |
755 | else { |
756 | rds_recv_incoming(conn, conn->c_faddr, conn->c_laddr, |
757 | &iwinc->ii_inc, GFP_ATOMIC, |
758 | KM_SOFTIRQ0); |
759 | state->ack_next = be64_to_cpu(hdr->h_sequence); |
760 | state->ack_next_valid = 1; |
761 | } |
762 | |
763 | /* Evaluate the ACK_REQUIRED flag *after* we received |
764 | * the complete frame, and after bumping the next_rx |
765 | * sequence. */ |
766 | if (hdr->h_flags & RDS_FLAG_ACK_REQUIRED) { |
767 | rds_stats_inc(s_recv_ack_required); |
768 | state->ack_required = 1; |
769 | } |
770 | |
771 | rds_inc_put(&iwinc->ii_inc); |
772 | } |
773 | } |
774 | |
775 | /* |
776 | * Plucking the oldest entry from the ring can be done concurrently with |
777 | * the thread refilling the ring. Each ring operation is protected by |
778 | * spinlocks and the transient state of refilling doesn't change the |
779 | * recording of which entry is oldest. |
780 | * |
781 | * This relies on IB only calling one cq comp_handler for each cq so that |
782 | * there will only be one caller of rds_recv_incoming() per RDS connection. |
783 | */ |
784 | void rds_iw_recv_cq_comp_handler(struct ib_cq *cq, void *context) |
785 | { |
786 | struct rds_connection *conn = context; |
787 | struct rds_iw_connection *ic = conn->c_transport_data; |
788 | |
789 | rdsdebug("conn %p cq %p\n", conn, cq); |
790 | |
791 | rds_iw_stats_inc(s_iw_rx_cq_call); |
792 | |
793 | tasklet_schedule(&ic->i_recv_tasklet); |
794 | } |
795 | |
796 | static inline void rds_poll_cq(struct rds_iw_connection *ic, |
797 | struct rds_iw_ack_state *state) |
798 | { |
799 | struct rds_connection *conn = ic->conn; |
800 | struct ib_wc wc; |
801 | struct rds_iw_recv_work *recv; |
802 | |
803 | while (ib_poll_cq(ic->i_recv_cq, 1, &wc) > 0) { |
804 | rdsdebug("wc wr_id 0x%llx status %u byte_len %u imm_data %u\n", |
805 | (unsigned long long)wc.wr_id, wc.status, wc.byte_len, |
806 | be32_to_cpu(wc.ex.imm_data)); |
807 | rds_iw_stats_inc(s_iw_rx_cq_event); |
808 | |
809 | recv = &ic->i_recvs[rds_iw_ring_oldest(&ic->i_recv_ring)]; |
810 | |
811 | rds_iw_recv_unmap_page(ic, recv); |
812 | |
813 | /* |
814 | * Also process recvs in connecting state because it is possible |
815 | * to get a recv completion _before_ the rdmacm ESTABLISHED |
816 | * event is processed. |
817 | */ |
818 | if (rds_conn_up(conn) || rds_conn_connecting(conn)) { |
819 | /* We expect errors as the qp is drained during shutdown */ |
820 | if (wc.status == IB_WC_SUCCESS) { |
821 | rds_iw_process_recv(conn, recv, wc.byte_len, state); |
822 | } else { |
823 | rds_iw_conn_error(conn, "recv completion on " |
824 | "%pI4 had status %u, disconnecting and " |
825 | "reconnecting\n", &conn->c_faddr, |
826 | wc.status); |
827 | } |
828 | } |
829 | |
830 | rds_iw_ring_free(&ic->i_recv_ring, 1); |
831 | } |
832 | } |
833 | |
834 | void rds_iw_recv_tasklet_fn(unsigned long data) |
835 | { |
836 | struct rds_iw_connection *ic = (struct rds_iw_connection *) data; |
837 | struct rds_connection *conn = ic->conn; |
838 | struct rds_iw_ack_state state = { 0, }; |
839 | |
840 | rds_poll_cq(ic, &state); |
841 | ib_req_notify_cq(ic->i_recv_cq, IB_CQ_SOLICITED); |
842 | rds_poll_cq(ic, &state); |
843 | |
844 | if (state.ack_next_valid) |
845 | rds_iw_set_ack(ic, state.ack_next, state.ack_required); |
846 | if (state.ack_recv_valid && state.ack_recv > ic->i_ack_recv) { |
847 | rds_send_drop_acked(conn, state.ack_recv, NULL); |
848 | ic->i_ack_recv = state.ack_recv; |
849 | } |
850 | if (rds_conn_up(conn)) |
851 | rds_iw_attempt_ack(ic); |
852 | |
853 | /* If we ever end up with a really empty receive ring, we're |
854 | * in deep trouble, as the sender will definitely see RNR |
855 | * timeouts. */ |
856 | if (rds_iw_ring_empty(&ic->i_recv_ring)) |
857 | rds_iw_stats_inc(s_iw_rx_ring_empty); |
858 | |
859 | /* |
860 | * If the ring is running low, then schedule the thread to refill. |
861 | */ |
862 | if (rds_iw_ring_low(&ic->i_recv_ring)) |
863 | queue_delayed_work(rds_wq, &conn->c_recv_w, 0); |
864 | } |
865 | |
866 | int rds_iw_recv(struct rds_connection *conn) |
867 | { |
868 | struct rds_iw_connection *ic = conn->c_transport_data; |
869 | int ret = 0; |
870 | |
871 | rdsdebug("conn %p\n", conn); |
872 | |
873 | /* |
874 | * If we get a temporary posting failure in this context then |
875 | * we're really low and we want the caller to back off for a bit. |
876 | */ |
877 | mutex_lock(&ic->i_recv_mutex); |
878 | if (rds_iw_recv_refill(conn, GFP_KERNEL, GFP_HIGHUSER, 0)) |
879 | ret = -ENOMEM; |
880 | else |
881 | rds_iw_stats_inc(s_iw_rx_refill_from_thread); |
882 | mutex_unlock(&ic->i_recv_mutex); |
883 | |
884 | if (rds_conn_up(conn)) |
885 | rds_iw_attempt_ack(ic); |
886 | |
887 | return ret; |
888 | } |
889 | |
890 | int __init rds_iw_recv_init(void) |
891 | { |
892 | struct sysinfo si; |
893 | int ret = -ENOMEM; |
894 | |
895 | /* Default to 30% of all available RAM for recv memory */ |
896 | si_meminfo(&si); |
897 | rds_iw_sysctl_max_recv_allocation = si.totalram / 3 * PAGE_SIZE / RDS_FRAG_SIZE; |
898 | |
899 | rds_iw_incoming_slab = kmem_cache_create("rds_iw_incoming", |
900 | sizeof(struct rds_iw_incoming), |
901 | 0, 0, NULL); |
902 | if (rds_iw_incoming_slab == NULL) |
903 | goto out; |
904 | |
905 | rds_iw_frag_slab = kmem_cache_create("rds_iw_frag", |
906 | sizeof(struct rds_page_frag), |
907 | 0, 0, NULL); |
908 | if (rds_iw_frag_slab == NULL) |
909 | kmem_cache_destroy(rds_iw_incoming_slab); |
910 | else |
911 | ret = 0; |
912 | out: |
913 | return ret; |
914 | } |
915 | |
916 | void rds_iw_recv_exit(void) |
917 | { |
918 | kmem_cache_destroy(rds_iw_incoming_slab); |
919 | kmem_cache_destroy(rds_iw_frag_slab); |
920 | } |
921 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9