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Andy Groverfcd8b7c2009-02-24 15:30:36 +00001/*
2 * Copyright (c) 2006 Oracle. All rights reserved.
3 *
4 * This software is available to you under a choice of one of two
5 * licenses. You may choose to be licensed under the terms of the GNU
6 * General Public License (GPL) Version 2, available from the file
7 * COPYING in the main directory of this source tree, or the
8 * OpenIB.org BSD license below:
9 *
10 * Redistribution and use in source and binary forms, with or
11 * without modification, are permitted provided that the following
12 * conditions are met:
13 *
14 * - Redistributions of source code must retain the above
15 * copyright notice, this list of conditions and the following
16 * disclaimer.
17 *
18 * - Redistributions in binary form must reproduce the above
19 * copyright notice, this list of conditions and the following
20 * disclaimer in the documentation and/or other materials
21 * provided with the distribution.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30 * SOFTWARE.
31 *
32 */
33#include <linux/kernel.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090034#include <linux/slab.h>
Andy Groverfcd8b7c2009-02-24 15:30:36 +000035#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
42static struct kmem_cache *rds_iw_incoming_slab;
43static struct kmem_cache *rds_iw_frag_slab;
44static atomic_t rds_iw_allocation = ATOMIC_INIT(0);
45
46static 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
53static void rds_iw_frag_free(struct rds_page_frag *frag)
54{
55 rdsdebug("frag %p page %p\n", frag, frag->f_page);
Andy Grover8690bfa2010-01-12 11:56:44 -080056 BUG_ON(frag->f_page);
Andy Groverfcd8b7c2009-02-24 15:30:36 +000057 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 */
69static 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
82void 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
110static 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
126void 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
137static 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
Andy Grover8690bfa2010-01-12 11:56:44 -0800146 if (!recv->r_iwinc) {
Andy Grover86357b12009-10-30 08:51:54 +0000147 if (!atomic_add_unless(&rds_iw_allocation, 1, rds_iw_sysctl_max_recv_allocation)) {
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000148 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);
Andy Grover8690bfa2010-01-12 11:56:44 -0800153 if (!recv->r_iwinc) {
Andy Grover86357b12009-10-30 08:51:54 +0000154 atomic_dec(&rds_iw_allocation);
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000155 goto out;
Andy Grover86357b12009-10-30 08:51:54 +0000156 }
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000157 INIT_LIST_HEAD(&recv->r_iwinc->ii_frags);
158 rds_inc_init(&recv->r_iwinc->ii_inc, conn, conn->c_faddr);
159 }
160
Andy Grover8690bfa2010-01-12 11:56:44 -0800161 if (!recv->r_frag) {
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000162 recv->r_frag = kmem_cache_alloc(rds_iw_frag_slab, kptr_gfp);
Andy Grover8690bfa2010-01-12 11:56:44 -0800163 if (!recv->r_frag)
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000164 goto out;
165 INIT_LIST_HEAD(&recv->r_frag->f_item);
166 recv->r_frag->f_page = NULL;
167 }
168
Andy Grover8690bfa2010-01-12 11:56:44 -0800169 if (!ic->i_frag.f_page) {
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000170 ic->i_frag.f_page = alloc_page(page_gfp);
Andy Grover8690bfa2010-01-12 11:56:44 -0800171 if (!ic->i_frag.f_page)
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000172 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;
212out:
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 */
224int 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
Joe Perchesf64f9e72009-11-29 16:55:45 -0800234 while ((prefill || rds_conn_up(conn)) &&
235 rds_iw_ring_alloc(&ic->i_recv_ring, 1, &pos)) {
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000236 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
Andy Grover809fa142010-01-12 14:41:46 -0800276static void rds_iw_inc_purge(struct rds_incoming *inc)
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000277{
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
292void 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
Al Viroc310e722014-11-20 09:21:14 -0500306int rds_iw_inc_copy_to_user(struct rds_incoming *inc, struct iov_iter *to)
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000307{
308 struct rds_iw_incoming *iwinc;
309 struct rds_page_frag *frag;
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000310 unsigned long to_copy;
311 unsigned long frag_off = 0;
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000312 int copied = 0;
313 int ret;
314 u32 len;
315
316 iwinc = container_of(inc, struct rds_iw_incoming, ii_inc);
317 frag = list_entry(iwinc->ii_frags.next, struct rds_page_frag, f_item);
318 len = be32_to_cpu(inc->i_hdr.h_len);
319
Al Viroc310e722014-11-20 09:21:14 -0500320 while (iov_iter_count(to) && copied < len) {
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000321 if (frag_off == RDS_FRAG_SIZE) {
322 frag = list_entry(frag->f_item.next,
323 struct rds_page_frag, f_item);
324 frag_off = 0;
325 }
Al Viroc310e722014-11-20 09:21:14 -0500326 to_copy = min_t(unsigned long, iov_iter_count(to),
327 RDS_FRAG_SIZE - frag_off);
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000328 to_copy = min_t(unsigned long, to_copy, len - copied);
329
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000330 /* XXX needs + offset for multiple recvs per page */
Al Viroc310e722014-11-20 09:21:14 -0500331 rds_stats_add(s_copy_to_user, to_copy);
332 ret = copy_page_to_iter(frag->f_page,
333 frag->f_offset + frag_off,
334 to_copy,
335 to);
336 if (ret != to_copy)
337 return -EFAULT;
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000338
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000339 frag_off += to_copy;
340 copied += to_copy;
341 }
342
343 return copied;
344}
345
346/* ic starts out kzalloc()ed */
347void rds_iw_recv_init_ack(struct rds_iw_connection *ic)
348{
349 struct ib_send_wr *wr = &ic->i_ack_wr;
350 struct ib_sge *sge = &ic->i_ack_sge;
351
352 sge->addr = ic->i_ack_dma;
353 sge->length = sizeof(struct rds_header);
354 sge->lkey = rds_iw_local_dma_lkey(ic);
355
356 wr->sg_list = sge;
357 wr->num_sge = 1;
358 wr->opcode = IB_WR_SEND;
359 wr->wr_id = RDS_IW_ACK_WR_ID;
360 wr->send_flags = IB_SEND_SIGNALED | IB_SEND_SOLICITED;
361}
362
363/*
364 * You'd think that with reliable IB connections you wouldn't need to ack
365 * messages that have been received. The problem is that IB hardware generates
366 * an ack message before it has DMAed the message into memory. This creates a
367 * potential message loss if the HCA is disabled for any reason between when it
368 * sends the ack and before the message is DMAed and processed. This is only a
369 * potential issue if another HCA is available for fail-over.
370 *
371 * When the remote host receives our ack they'll free the sent message from
372 * their send queue. To decrease the latency of this we always send an ack
373 * immediately after we've received messages.
374 *
375 * For simplicity, we only have one ack in flight at a time. This puts
376 * pressure on senders to have deep enough send queues to absorb the latency of
377 * a single ack frame being in flight. This might not be good enough.
378 *
379 * This is implemented by have a long-lived send_wr and sge which point to a
380 * statically allocated ack frame. This ack wr does not fall under the ring
381 * accounting that the tx and rx wrs do. The QP attribute specifically makes
382 * room for it beyond the ring size. Send completion notices its special
383 * wr_id and avoids working with the ring in that case.
384 */
Andy Grover8cbd9602009-04-01 08:20:20 +0000385#ifndef KERNEL_HAS_ATOMIC64
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000386static void rds_iw_set_ack(struct rds_iw_connection *ic, u64 seq,
387 int ack_required)
388{
Andy Grover8cbd9602009-04-01 08:20:20 +0000389 unsigned long flags;
390
391 spin_lock_irqsave(&ic->i_ack_lock, flags);
392 ic->i_ack_next = seq;
393 if (ack_required)
394 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
395 spin_unlock_irqrestore(&ic->i_ack_lock, flags);
396}
397
398static u64 rds_iw_get_ack(struct rds_iw_connection *ic)
399{
400 unsigned long flags;
401 u64 seq;
402
403 clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
404
405 spin_lock_irqsave(&ic->i_ack_lock, flags);
406 seq = ic->i_ack_next;
407 spin_unlock_irqrestore(&ic->i_ack_lock, flags);
408
409 return seq;
410}
411#else
412static void rds_iw_set_ack(struct rds_iw_connection *ic, u64 seq,
413 int ack_required)
414{
415 atomic64_set(&ic->i_ack_next, seq);
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000416 if (ack_required) {
Peter Zijlstra4e857c52014-03-17 18:06:10 +0100417 smp_mb__before_atomic();
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000418 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
419 }
420}
421
422static u64 rds_iw_get_ack(struct rds_iw_connection *ic)
423{
424 clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
Peter Zijlstra4e857c52014-03-17 18:06:10 +0100425 smp_mb__after_atomic();
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000426
Andy Grover8cbd9602009-04-01 08:20:20 +0000427 return atomic64_read(&ic->i_ack_next);
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000428}
Andy Grover8cbd9602009-04-01 08:20:20 +0000429#endif
430
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000431
432static void rds_iw_send_ack(struct rds_iw_connection *ic, unsigned int adv_credits)
433{
434 struct rds_header *hdr = ic->i_ack;
435 struct ib_send_wr *failed_wr;
436 u64 seq;
437 int ret;
438
439 seq = rds_iw_get_ack(ic);
440
441 rdsdebug("send_ack: ic %p ack %llu\n", ic, (unsigned long long) seq);
442 rds_message_populate_header(hdr, 0, 0, 0);
443 hdr->h_ack = cpu_to_be64(seq);
444 hdr->h_credit = adv_credits;
445 rds_message_make_checksum(hdr);
446 ic->i_ack_queued = jiffies;
447
448 ret = ib_post_send(ic->i_cm_id->qp, &ic->i_ack_wr, &failed_wr);
449 if (unlikely(ret)) {
450 /* Failed to send. Release the WR, and
451 * force another ACK.
452 */
453 clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
454 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
455
456 rds_iw_stats_inc(s_iw_ack_send_failure);
Andy Grover735f61e2010-03-11 13:49:55 +0000457
458 rds_iw_conn_error(ic->conn, "sending ack failed\n");
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000459 } else
460 rds_iw_stats_inc(s_iw_ack_sent);
461}
462
463/*
464 * There are 3 ways of getting acknowledgements to the peer:
465 * 1. We call rds_iw_attempt_ack from the recv completion handler
466 * to send an ACK-only frame.
467 * However, there can be only one such frame in the send queue
468 * at any time, so we may have to postpone it.
469 * 2. When another (data) packet is transmitted while there's
470 * an ACK in the queue, we piggyback the ACK sequence number
471 * on the data packet.
472 * 3. If the ACK WR is done sending, we get called from the
473 * send queue completion handler, and check whether there's
474 * another ACK pending (postponed because the WR was on the
475 * queue). If so, we transmit it.
476 *
477 * We maintain 2 variables:
478 * - i_ack_flags, which keeps track of whether the ACK WR
479 * is currently in the send queue or not (IB_ACK_IN_FLIGHT)
480 * - i_ack_next, which is the last sequence number we received
481 *
482 * Potentially, send queue and receive queue handlers can run concurrently.
Andy Grover8cbd9602009-04-01 08:20:20 +0000483 * It would be nice to not have to use a spinlock to synchronize things,
484 * but the one problem that rules this out is that 64bit updates are
485 * not atomic on all platforms. Things would be a lot simpler if
486 * we had atomic64 or maybe cmpxchg64 everywhere.
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000487 *
488 * Reconnecting complicates this picture just slightly. When we
489 * reconnect, we may be seeing duplicate packets. The peer
490 * is retransmitting them, because it hasn't seen an ACK for
491 * them. It is important that we ACK these.
492 *
493 * ACK mitigation adds a header flag "ACK_REQUIRED"; any packet with
494 * this flag set *MUST* be acknowledged immediately.
495 */
496
497/*
498 * When we get here, we're called from the recv queue handler.
499 * Check whether we ought to transmit an ACK.
500 */
501void rds_iw_attempt_ack(struct rds_iw_connection *ic)
502{
503 unsigned int adv_credits;
504
505 if (!test_bit(IB_ACK_REQUESTED, &ic->i_ack_flags))
506 return;
507
508 if (test_and_set_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags)) {
509 rds_iw_stats_inc(s_iw_ack_send_delayed);
510 return;
511 }
512
513 /* Can we get a send credit? */
Steve Wise7b70d032009-04-09 14:09:39 +0000514 if (!rds_iw_send_grab_credits(ic, 1, &adv_credits, 0, RDS_MAX_ADV_CREDIT)) {
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000515 rds_iw_stats_inc(s_iw_tx_throttle);
516 clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
517 return;
518 }
519
520 clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
521 rds_iw_send_ack(ic, adv_credits);
522}
523
524/*
525 * We get here from the send completion handler, when the
526 * adapter tells us the ACK frame was sent.
527 */
528void rds_iw_ack_send_complete(struct rds_iw_connection *ic)
529{
530 clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
531 rds_iw_attempt_ack(ic);
532}
533
534/*
535 * This is called by the regular xmit code when it wants to piggyback
536 * an ACK on an outgoing frame.
537 */
538u64 rds_iw_piggyb_ack(struct rds_iw_connection *ic)
539{
540 if (test_and_clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags))
541 rds_iw_stats_inc(s_iw_ack_send_piggybacked);
542 return rds_iw_get_ack(ic);
543}
544
545/*
546 * It's kind of lame that we're copying from the posted receive pages into
547 * long-lived bitmaps. We could have posted the bitmaps and rdma written into
548 * them. But receiving new congestion bitmaps should be a *rare* event, so
549 * hopefully we won't need to invest that complexity in making it more
550 * efficient. By copying we can share a simpler core with TCP which has to
551 * copy.
552 */
553static void rds_iw_cong_recv(struct rds_connection *conn,
554 struct rds_iw_incoming *iwinc)
555{
556 struct rds_cong_map *map;
557 unsigned int map_off;
558 unsigned int map_page;
559 struct rds_page_frag *frag;
560 unsigned long frag_off;
561 unsigned long to_copy;
562 unsigned long copied;
563 uint64_t uncongested = 0;
564 void *addr;
565
566 /* catch completely corrupt packets */
567 if (be32_to_cpu(iwinc->ii_inc.i_hdr.h_len) != RDS_CONG_MAP_BYTES)
568 return;
569
570 map = conn->c_fcong;
571 map_page = 0;
572 map_off = 0;
573
574 frag = list_entry(iwinc->ii_frags.next, struct rds_page_frag, f_item);
575 frag_off = 0;
576
577 copied = 0;
578
579 while (copied < RDS_CONG_MAP_BYTES) {
580 uint64_t *src, *dst;
581 unsigned int k;
582
583 to_copy = min(RDS_FRAG_SIZE - frag_off, PAGE_SIZE - map_off);
584 BUG_ON(to_copy & 7); /* Must be 64bit aligned. */
585
Cong Wang6114eab2011-11-25 23:14:40 +0800586 addr = kmap_atomic(frag->f_page);
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000587
588 src = addr + frag_off;
589 dst = (void *)map->m_page_addrs[map_page] + map_off;
590 for (k = 0; k < to_copy; k += 8) {
591 /* Record ports that became uncongested, ie
592 * bits that changed from 0 to 1. */
593 uncongested |= ~(*src) & *dst;
594 *dst++ = *src++;
595 }
Cong Wang6114eab2011-11-25 23:14:40 +0800596 kunmap_atomic(addr);
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000597
598 copied += to_copy;
599
600 map_off += to_copy;
601 if (map_off == PAGE_SIZE) {
602 map_off = 0;
603 map_page++;
604 }
605
606 frag_off += to_copy;
607 if (frag_off == RDS_FRAG_SIZE) {
608 frag = list_entry(frag->f_item.next,
609 struct rds_page_frag, f_item);
610 frag_off = 0;
611 }
612 }
613
614 /* the congestion map is in little endian order */
615 uncongested = le64_to_cpu(uncongested);
616
617 rds_cong_map_updated(map, uncongested);
618}
619
620/*
621 * Rings are posted with all the allocations they'll need to queue the
622 * incoming message to the receiving socket so this can't fail.
623 * All fragments start with a header, so we can make sure we're not receiving
624 * garbage, and we can tell a small 8 byte fragment from an ACK frame.
625 */
626struct rds_iw_ack_state {
627 u64 ack_next;
628 u64 ack_recv;
629 unsigned int ack_required:1;
630 unsigned int ack_next_valid:1;
631 unsigned int ack_recv_valid:1;
632};
633
634static void rds_iw_process_recv(struct rds_connection *conn,
635 struct rds_iw_recv_work *recv, u32 byte_len,
636 struct rds_iw_ack_state *state)
637{
638 struct rds_iw_connection *ic = conn->c_transport_data;
639 struct rds_iw_incoming *iwinc = ic->i_iwinc;
640 struct rds_header *ihdr, *hdr;
641
642 /* XXX shut down the connection if port 0,0 are seen? */
643
644 rdsdebug("ic %p iwinc %p recv %p byte len %u\n", ic, iwinc, recv,
645 byte_len);
646
647 if (byte_len < sizeof(struct rds_header)) {
648 rds_iw_conn_error(conn, "incoming message "
Masanari Iida5fd5c442012-02-09 23:17:15 +0900649 "from %pI4 didn't include a "
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000650 "header, disconnecting and "
651 "reconnecting\n",
652 &conn->c_faddr);
653 return;
654 }
655 byte_len -= sizeof(struct rds_header);
656
657 ihdr = &ic->i_recv_hdrs[recv - ic->i_recvs];
658
659 /* Validate the checksum. */
660 if (!rds_message_verify_checksum(ihdr)) {
661 rds_iw_conn_error(conn, "incoming message "
662 "from %pI4 has corrupted header - "
663 "forcing a reconnect\n",
664 &conn->c_faddr);
665 rds_stats_inc(s_recv_drop_bad_checksum);
666 return;
667 }
668
669 /* Process the ACK sequence which comes with every packet */
670 state->ack_recv = be64_to_cpu(ihdr->h_ack);
671 state->ack_recv_valid = 1;
672
673 /* Process the credits update if there was one */
674 if (ihdr->h_credit)
675 rds_iw_send_add_credits(conn, ihdr->h_credit);
676
677 if (ihdr->h_sport == 0 && ihdr->h_dport == 0 && byte_len == 0) {
678 /* This is an ACK-only packet. The fact that it gets
679 * special treatment here is that historically, ACKs
680 * were rather special beasts.
681 */
682 rds_iw_stats_inc(s_iw_ack_received);
683
684 /*
685 * Usually the frags make their way on to incs and are then freed as
686 * the inc is freed. We don't go that route, so we have to drop the
687 * page ref ourselves. We can't just leave the page on the recv
688 * because that confuses the dma mapping of pages and each recv's use
689 * of a partial page. We can leave the frag, though, it will be
690 * reused.
691 *
692 * FIXME: Fold this into the code path below.
693 */
694 rds_iw_frag_drop_page(recv->r_frag);
695 return;
696 }
697
698 /*
699 * If we don't already have an inc on the connection then this
700 * fragment has a header and starts a message.. copy its header
701 * into the inc and save the inc so we can hang upcoming fragments
702 * off its list.
703 */
Andy Grover8690bfa2010-01-12 11:56:44 -0800704 if (!iwinc) {
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000705 iwinc = recv->r_iwinc;
706 recv->r_iwinc = NULL;
707 ic->i_iwinc = iwinc;
708
709 hdr = &iwinc->ii_inc.i_hdr;
710 memcpy(hdr, ihdr, sizeof(*hdr));
711 ic->i_recv_data_rem = be32_to_cpu(hdr->h_len);
712
713 rdsdebug("ic %p iwinc %p rem %u flag 0x%x\n", ic, iwinc,
714 ic->i_recv_data_rem, hdr->h_flags);
715 } else {
716 hdr = &iwinc->ii_inc.i_hdr;
717 /* We can't just use memcmp here; fragments of a
718 * single message may carry different ACKs */
Joe Perchesf64f9e72009-11-29 16:55:45 -0800719 if (hdr->h_sequence != ihdr->h_sequence ||
720 hdr->h_len != ihdr->h_len ||
721 hdr->h_sport != ihdr->h_sport ||
722 hdr->h_dport != ihdr->h_dport) {
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000723 rds_iw_conn_error(conn,
724 "fragment header mismatch; forcing reconnect\n");
725 return;
726 }
727 }
728
729 list_add_tail(&recv->r_frag->f_item, &iwinc->ii_frags);
730 recv->r_frag = NULL;
731
732 if (ic->i_recv_data_rem > RDS_FRAG_SIZE)
733 ic->i_recv_data_rem -= RDS_FRAG_SIZE;
734 else {
735 ic->i_recv_data_rem = 0;
736 ic->i_iwinc = NULL;
737
738 if (iwinc->ii_inc.i_hdr.h_flags == RDS_FLAG_CONG_BITMAP)
739 rds_iw_cong_recv(conn, iwinc);
740 else {
741 rds_recv_incoming(conn, conn->c_faddr, conn->c_laddr,
Cong Wang6114eab2011-11-25 23:14:40 +0800742 &iwinc->ii_inc, GFP_ATOMIC);
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000743 state->ack_next = be64_to_cpu(hdr->h_sequence);
744 state->ack_next_valid = 1;
745 }
746
747 /* Evaluate the ACK_REQUIRED flag *after* we received
748 * the complete frame, and after bumping the next_rx
749 * sequence. */
750 if (hdr->h_flags & RDS_FLAG_ACK_REQUIRED) {
751 rds_stats_inc(s_recv_ack_required);
752 state->ack_required = 1;
753 }
754
755 rds_inc_put(&iwinc->ii_inc);
756 }
757}
758
759/*
760 * Plucking the oldest entry from the ring can be done concurrently with
761 * the thread refilling the ring. Each ring operation is protected by
762 * spinlocks and the transient state of refilling doesn't change the
763 * recording of which entry is oldest.
764 *
765 * This relies on IB only calling one cq comp_handler for each cq so that
766 * there will only be one caller of rds_recv_incoming() per RDS connection.
767 */
768void rds_iw_recv_cq_comp_handler(struct ib_cq *cq, void *context)
769{
770 struct rds_connection *conn = context;
771 struct rds_iw_connection *ic = conn->c_transport_data;
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000772
773 rdsdebug("conn %p cq %p\n", conn, cq);
774
775 rds_iw_stats_inc(s_iw_rx_cq_call);
776
Andy Groverd521b632009-10-30 08:51:57 +0000777 tasklet_schedule(&ic->i_recv_tasklet);
778}
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000779
Andy Groverd521b632009-10-30 08:51:57 +0000780static inline void rds_poll_cq(struct rds_iw_connection *ic,
781 struct rds_iw_ack_state *state)
782{
783 struct rds_connection *conn = ic->conn;
784 struct ib_wc wc;
785 struct rds_iw_recv_work *recv;
786
787 while (ib_poll_cq(ic->i_recv_cq, 1, &wc) > 0) {
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000788 rdsdebug("wc wr_id 0x%llx status %u byte_len %u imm_data %u\n",
789 (unsigned long long)wc.wr_id, wc.status, wc.byte_len,
790 be32_to_cpu(wc.ex.imm_data));
791 rds_iw_stats_inc(s_iw_rx_cq_event);
792
793 recv = &ic->i_recvs[rds_iw_ring_oldest(&ic->i_recv_ring)];
794
795 rds_iw_recv_unmap_page(ic, recv);
796
797 /*
798 * Also process recvs in connecting state because it is possible
799 * to get a recv completion _before_ the rdmacm ESTABLISHED
800 * event is processed.
801 */
802 if (rds_conn_up(conn) || rds_conn_connecting(conn)) {
803 /* We expect errors as the qp is drained during shutdown */
804 if (wc.status == IB_WC_SUCCESS) {
Andy Groverd521b632009-10-30 08:51:57 +0000805 rds_iw_process_recv(conn, recv, wc.byte_len, state);
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000806 } else {
807 rds_iw_conn_error(conn, "recv completion on "
808 "%pI4 had status %u, disconnecting and "
809 "reconnecting\n", &conn->c_faddr,
810 wc.status);
811 }
812 }
813
814 rds_iw_ring_free(&ic->i_recv_ring, 1);
815 }
Andy Groverd521b632009-10-30 08:51:57 +0000816}
817
818void rds_iw_recv_tasklet_fn(unsigned long data)
819{
820 struct rds_iw_connection *ic = (struct rds_iw_connection *) data;
821 struct rds_connection *conn = ic->conn;
822 struct rds_iw_ack_state state = { 0, };
823
824 rds_poll_cq(ic, &state);
825 ib_req_notify_cq(ic->i_recv_cq, IB_CQ_SOLICITED);
826 rds_poll_cq(ic, &state);
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000827
828 if (state.ack_next_valid)
829 rds_iw_set_ack(ic, state.ack_next, state.ack_required);
830 if (state.ack_recv_valid && state.ack_recv > ic->i_ack_recv) {
831 rds_send_drop_acked(conn, state.ack_recv, NULL);
832 ic->i_ack_recv = state.ack_recv;
833 }
834 if (rds_conn_up(conn))
835 rds_iw_attempt_ack(ic);
836
837 /* If we ever end up with a really empty receive ring, we're
838 * in deep trouble, as the sender will definitely see RNR
839 * timeouts. */
840 if (rds_iw_ring_empty(&ic->i_recv_ring))
841 rds_iw_stats_inc(s_iw_rx_ring_empty);
842
843 /*
844 * If the ring is running low, then schedule the thread to refill.
845 */
846 if (rds_iw_ring_low(&ic->i_recv_ring))
847 queue_delayed_work(rds_wq, &conn->c_recv_w, 0);
848}
849
850int rds_iw_recv(struct rds_connection *conn)
851{
852 struct rds_iw_connection *ic = conn->c_transport_data;
853 int ret = 0;
854
855 rdsdebug("conn %p\n", conn);
856
857 /*
858 * If we get a temporary posting failure in this context then
859 * we're really low and we want the caller to back off for a bit.
860 */
861 mutex_lock(&ic->i_recv_mutex);
862 if (rds_iw_recv_refill(conn, GFP_KERNEL, GFP_HIGHUSER, 0))
863 ret = -ENOMEM;
864 else
865 rds_iw_stats_inc(s_iw_rx_refill_from_thread);
866 mutex_unlock(&ic->i_recv_mutex);
867
868 if (rds_conn_up(conn))
869 rds_iw_attempt_ack(ic);
870
871 return ret;
872}
873
Zach Brownef87b7e2010-07-09 12:26:20 -0700874int rds_iw_recv_init(void)
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000875{
876 struct sysinfo si;
877 int ret = -ENOMEM;
878
879 /* Default to 30% of all available RAM for recv memory */
880 si_meminfo(&si);
881 rds_iw_sysctl_max_recv_allocation = si.totalram / 3 * PAGE_SIZE / RDS_FRAG_SIZE;
882
883 rds_iw_incoming_slab = kmem_cache_create("rds_iw_incoming",
884 sizeof(struct rds_iw_incoming),
885 0, 0, NULL);
Andy Grover8690bfa2010-01-12 11:56:44 -0800886 if (!rds_iw_incoming_slab)
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000887 goto out;
888
889 rds_iw_frag_slab = kmem_cache_create("rds_iw_frag",
890 sizeof(struct rds_page_frag),
891 0, 0, NULL);
Andy Grover8690bfa2010-01-12 11:56:44 -0800892 if (!rds_iw_frag_slab)
Andy Groverfcd8b7c2009-02-24 15:30:36 +0000893 kmem_cache_destroy(rds_iw_incoming_slab);
894 else
895 ret = 0;
896out:
897 return ret;
898}
899
900void rds_iw_recv_exit(void)
901{
902 kmem_cache_destroy(rds_iw_incoming_slab);
903 kmem_cache_destroy(rds_iw_frag_slab);
904}