~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/net/rds/iw_recv.c

Version: ~ [ linux-5.2-rc1 ] ~ [ linux-5.1.2 ] ~ [ linux-5.0.16 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.43 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.119 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.176 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.179 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.139 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.67 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  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);
 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) {
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) {
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) {
162                 recv->r_frag = kmem_cache_alloc(rds_iw_frag_slab, kptr_gfp);
163                 if (!recv->r_frag)
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) {
170                 ic->i_frag.f_page = alloc_page(page_gfp);
171                 if (!ic->i_frag.f_page)
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 static 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 
473                 rds_iw_conn_error(ic->conn, "sending ack failed\n");
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) {
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 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)
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)
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 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp