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