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/in.h> 35#include <linux/device.h> 36#include <linux/dmapool.h> 37#include <linux/ratelimit.h> 38 39#include "rds.h" 40#include "ib.h" 41 42static char *rds_ib_wc_status_strings[] = { 43#define RDS_IB_WC_STATUS_STR(foo) \ 44 [IB_WC_##foo] = __stringify(IB_WC_##foo) 45 RDS_IB_WC_STATUS_STR(SUCCESS), 46 RDS_IB_WC_STATUS_STR(LOC_LEN_ERR), 47 RDS_IB_WC_STATUS_STR(LOC_QP_OP_ERR), 48 RDS_IB_WC_STATUS_STR(LOC_EEC_OP_ERR), 49 RDS_IB_WC_STATUS_STR(LOC_PROT_ERR), 50 RDS_IB_WC_STATUS_STR(WR_FLUSH_ERR), 51 RDS_IB_WC_STATUS_STR(MW_BIND_ERR), 52 RDS_IB_WC_STATUS_STR(BAD_RESP_ERR), 53 RDS_IB_WC_STATUS_STR(LOC_ACCESS_ERR), 54 RDS_IB_WC_STATUS_STR(REM_INV_REQ_ERR), 55 RDS_IB_WC_STATUS_STR(REM_ACCESS_ERR), 56 RDS_IB_WC_STATUS_STR(REM_OP_ERR), 57 RDS_IB_WC_STATUS_STR(RETRY_EXC_ERR), 58 RDS_IB_WC_STATUS_STR(RNR_RETRY_EXC_ERR), 59 RDS_IB_WC_STATUS_STR(LOC_RDD_VIOL_ERR), 60 RDS_IB_WC_STATUS_STR(REM_INV_RD_REQ_ERR), 61 RDS_IB_WC_STATUS_STR(REM_ABORT_ERR), 62 RDS_IB_WC_STATUS_STR(INV_EECN_ERR), 63 RDS_IB_WC_STATUS_STR(INV_EEC_STATE_ERR), 64 RDS_IB_WC_STATUS_STR(FATAL_ERR), 65 RDS_IB_WC_STATUS_STR(RESP_TIMEOUT_ERR), 66 RDS_IB_WC_STATUS_STR(GENERAL_ERR), 67#undef RDS_IB_WC_STATUS_STR 68}; 69 70char *rds_ib_wc_status_str(enum ib_wc_status status) 71{ 72 return rds_str_array(rds_ib_wc_status_strings, 73 ARRAY_SIZE(rds_ib_wc_status_strings), status); 74} 75 76/* 77 * Convert IB-specific error message to RDS error message and call core 78 * completion handler. 79 */ 80static void rds_ib_send_complete(struct rds_message *rm, 81 int wc_status, 82 void (*complete)(struct rds_message *rm, int status)) 83{ 84 int notify_status; 85 86 switch (wc_status) { 87 case IB_WC_WR_FLUSH_ERR: 88 return; 89 90 case IB_WC_SUCCESS: 91 notify_status = RDS_RDMA_SUCCESS; 92 break; 93 94 case IB_WC_REM_ACCESS_ERR: 95 notify_status = RDS_RDMA_REMOTE_ERROR; 96 break; 97 98 default: 99 notify_status = RDS_RDMA_OTHER_ERROR; 100 break; 101 } 102 complete(rm, notify_status); 103} 104 105static void rds_ib_send_unmap_data(struct rds_ib_connection *ic, 106 struct rm_data_op *op, 107 int wc_status) 108{ 109 if (op->op_nents) 110 ib_dma_unmap_sg(ic->i_cm_id->device, 111 op->op_sg, op->op_nents, 112 DMA_TO_DEVICE); 113} 114 115static void rds_ib_send_unmap_rdma(struct rds_ib_connection *ic, 116 struct rm_rdma_op *op, 117 int wc_status) 118{ 119 if (op->op_mapped) { 120 ib_dma_unmap_sg(ic->i_cm_id->device, 121 op->op_sg, op->op_nents, 122 op->op_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE); 123 op->op_mapped = 0; 124 } 125 126 /* If the user asked for a completion notification on this 127 * message, we can implement three different semantics: 128 * 1. Notify when we received the ACK on the RDS message 129 * that was queued with the RDMA. This provides reliable 130 * notification of RDMA status at the expense of a one-way 131 * packet delay. 132 * 2. Notify when the IB stack gives us the completion event for 133 * the RDMA operation. 134 * 3. Notify when the IB stack gives us the completion event for 135 * the accompanying RDS messages. 136 * Here, we implement approach #3. To implement approach #2, 137 * we would need to take an event for the rdma WR. To implement #1, 138 * don't call rds_rdma_send_complete at all, and fall back to the notify 139 * handling in the ACK processing code. 140 * 141 * Note: There's no need to explicitly sync any RDMA buffers using 142 * ib_dma_sync_sg_for_cpu - the completion for the RDMA 143 * operation itself unmapped the RDMA buffers, which takes care 144 * of synching. 145 */ 146 rds_ib_send_complete(container_of(op, struct rds_message, rdma), 147 wc_status, rds_rdma_send_complete); 148 149 if (op->op_write) 150 rds_stats_add(s_send_rdma_bytes, op->op_bytes); 151 else 152 rds_stats_add(s_recv_rdma_bytes, op->op_bytes); 153} 154 155static void rds_ib_send_unmap_atomic(struct rds_ib_connection *ic, 156 struct rm_atomic_op *op, 157 int wc_status) 158{ 159 /* unmap atomic recvbuf */ 160 if (op->op_mapped) { 161 ib_dma_unmap_sg(ic->i_cm_id->device, op->op_sg, 1, 162 DMA_FROM_DEVICE); 163 op->op_mapped = 0; 164 } 165 166 rds_ib_send_complete(container_of(op, struct rds_message, atomic), 167 wc_status, rds_atomic_send_complete); 168 169 if (op->op_type == RDS_ATOMIC_TYPE_CSWP) 170 rds_ib_stats_inc(s_ib_atomic_cswp); 171 else 172 rds_ib_stats_inc(s_ib_atomic_fadd); 173} 174 175/* 176 * Unmap the resources associated with a struct send_work. 177 * 178 * Returns the rm for no good reason other than it is unobtainable 179 * other than by switching on wr.opcode, currently, and the caller, 180 * the event handler, needs it. 181 */ 182static struct rds_message *rds_ib_send_unmap_op(struct rds_ib_connection *ic, 183 struct rds_ib_send_work *send, 184 int wc_status) 185{ 186 struct rds_message *rm = NULL; 187 188 /* In the error case, wc.opcode sometimes contains garbage */ 189 switch (send->s_wr.opcode) { 190 case IB_WR_SEND: 191 if (send->s_op) { 192 rm = container_of(send->s_op, struct rds_message, data); 193 rds_ib_send_unmap_data(ic, send->s_op, wc_status); 194 } 195 break; 196 case IB_WR_RDMA_WRITE: 197 case IB_WR_RDMA_READ: 198 if (send->s_op) { 199 rm = container_of(send->s_op, struct rds_message, rdma); 200 rds_ib_send_unmap_rdma(ic, send->s_op, wc_status); 201 } 202 break; 203 case IB_WR_ATOMIC_FETCH_AND_ADD: 204 case IB_WR_ATOMIC_CMP_AND_SWP: 205 if (send->s_op) { 206 rm = container_of(send->s_op, struct rds_message, atomic); 207 rds_ib_send_unmap_atomic(ic, send->s_op, wc_status); 208 } 209 break; 210 default: 211 printk_ratelimited(KERN_NOTICE 212 "RDS/IB: %s: unexpected opcode 0x%x in WR!\n", 213 __func__, send->s_wr.opcode); 214 break; 215 } 216 217 send->s_wr.opcode = 0xdead; 218 219 return rm; 220} 221 222void rds_ib_send_init_ring(struct rds_ib_connection *ic) 223{ 224 struct rds_ib_send_work *send; 225 u32 i; 226 227 for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) { 228 struct ib_sge *sge; 229 230 send->s_op = NULL; 231 232 send->s_wr.wr_id = i; 233 send->s_wr.sg_list = send->s_sge; 234 send->s_wr.ex.imm_data = 0; 235 236 sge = &send->s_sge[0]; 237 sge->addr = ic->i_send_hdrs_dma + (i * sizeof(struct rds_header)); 238 sge->length = sizeof(struct rds_header); 239 sge->lkey = ic->i_mr->lkey; 240 241 send->s_sge[1].lkey = ic->i_mr->lkey; 242 } 243} 244 245void rds_ib_send_clear_ring(struct rds_ib_connection *ic) 246{ 247 struct rds_ib_send_work *send; 248 u32 i; 249 250 for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) { 251 if (send->s_op && send->s_wr.opcode != 0xdead) 252 rds_ib_send_unmap_op(ic, send, IB_WC_WR_FLUSH_ERR); 253 } 254} 255 256/* 257 * The only fast path caller always has a non-zero nr, so we don't 258 * bother testing nr before performing the atomic sub. 259 */ 260static void rds_ib_sub_signaled(struct rds_ib_connection *ic, int nr) 261{ 262 if ((atomic_sub_return(nr, &ic->i_signaled_sends) == 0) && 263 waitqueue_active(&rds_ib_ring_empty_wait)) 264 wake_up(&rds_ib_ring_empty_wait); 265 BUG_ON(atomic_read(&ic->i_signaled_sends) < 0); 266} 267 268/* 269 * The _oldest/_free ring operations here race cleanly with the alloc/unalloc 270 * operations performed in the send path. As the sender allocs and potentially 271 * unallocs the next free entry in the ring it doesn't alter which is 272 * the next to be freed, which is what this is concerned with. 273 */ 274void rds_ib_send_cq_comp_handler(struct ib_cq *cq, void *context) 275{ 276 struct rds_connection *conn = context; 277 struct rds_ib_connection *ic = conn->c_transport_data; 278 struct rds_message *rm = NULL; 279 struct ib_wc wc; 280 struct rds_ib_send_work *send; 281 u32 completed; 282 u32 oldest; 283 u32 i = 0; 284 int ret; 285 int nr_sig = 0; 286 287 rdsdebug("cq %p conn %p\n", cq, conn); 288 rds_ib_stats_inc(s_ib_tx_cq_call); 289 ret = ib_req_notify_cq(cq, IB_CQ_NEXT_COMP); 290 if (ret) 291 rdsdebug("ib_req_notify_cq send failed: %d\n", ret); 292 293 while (ib_poll_cq(cq, 1, &wc) > 0) { 294 rdsdebug("wc wr_id 0x%llx status %u (%s) byte_len %u imm_data %u\n", 295 (unsigned long long)wc.wr_id, wc.status, 296 rds_ib_wc_status_str(wc.status), wc.byte_len, 297 be32_to_cpu(wc.ex.imm_data)); 298 rds_ib_stats_inc(s_ib_tx_cq_event); 299 300 if (wc.wr_id == RDS_IB_ACK_WR_ID) { 301 if (time_after(jiffies, ic->i_ack_queued + HZ/2)) 302 rds_ib_stats_inc(s_ib_tx_stalled); 303 rds_ib_ack_send_complete(ic); 304 continue; 305 } 306 307 oldest = rds_ib_ring_oldest(&ic->i_send_ring); 308 309 completed = rds_ib_ring_completed(&ic->i_send_ring, wc.wr_id, oldest); 310 311 for (i = 0; i < completed; i++) { 312 send = &ic->i_sends[oldest]; 313 if (send->s_wr.send_flags & IB_SEND_SIGNALED) 314 nr_sig++; 315 316 rm = rds_ib_send_unmap_op(ic, send, wc.status); 317 318 if (time_after(jiffies, send->s_queued + HZ/2)) 319 rds_ib_stats_inc(s_ib_tx_stalled); 320 321 if (send->s_op) { 322 if (send->s_op == rm->m_final_op) { 323 /* If anyone waited for this message to get flushed out, wake 324 * them up now */ 325 rds_message_unmapped(rm); 326 } 327 rds_message_put(rm); 328 send->s_op = NULL; 329 } 330 331 oldest = (oldest + 1) % ic->i_send_ring.w_nr; 332 } 333 334 rds_ib_ring_free(&ic->i_send_ring, completed); 335 rds_ib_sub_signaled(ic, nr_sig); 336 nr_sig = 0; 337 338 if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags) || 339 test_bit(0, &conn->c_map_queued)) 340 queue_delayed_work(rds_wq, &conn->c_send_w, 0); 341 342 /* We expect errors as the qp is drained during shutdown */ 343 if (wc.status != IB_WC_SUCCESS && rds_conn_up(conn)) { 344 rds_ib_conn_error(conn, "send completion on %pI4 had status " 345 "%u (%s), disconnecting and reconnecting\n", 346 &conn->c_faddr, wc.status, 347 rds_ib_wc_status_str(wc.status)); 348 } 349 } 350} 351 352/* 353 * This is the main function for allocating credits when sending 354 * messages. 355 * 356 * Conceptually, we have two counters: 357 * - send credits: this tells us how many WRs we're allowed 358 * to submit without overruning the receiver's queue. For 359 * each SEND WR we post, we decrement this by one. 360 * 361 * - posted credits: this tells us how many WRs we recently 362 * posted to the receive queue. This value is transferred 363 * to the peer as a "credit update" in a RDS header field. 364 * Every time we transmit credits to the peer, we subtract 365 * the amount of transferred credits from this counter. 366 * 367 * It is essential that we avoid situations where both sides have 368 * exhausted their send credits, and are unable to send new credits 369 * to the peer. We achieve this by requiring that we send at least 370 * one credit update to the peer before exhausting our credits. 371 * When new credits arrive, we subtract one credit that is withheld 372 * until we've posted new buffers and are ready to transmit these 373 * credits (see rds_ib_send_add_credits below). 374 * 375 * The RDS send code is essentially single-threaded; rds_send_xmit 376 * sets RDS_IN_XMIT to ensure exclusive access to the send ring. 377 * However, the ACK sending code is independent and can race with 378 * message SENDs. 379 * 380 * In the send path, we need to update the counters for send credits 381 * and the counter of posted buffers atomically - when we use the 382 * last available credit, we cannot allow another thread to race us 383 * and grab the posted credits counter. Hence, we have to use a 384 * spinlock to protect the credit counter, or use atomics. 385 * 386 * Spinlocks shared between the send and the receive path are bad, 387 * because they create unnecessary delays. An early implementation 388 * using a spinlock showed a 5% degradation in throughput at some 389 * loads. 390 * 391 * This implementation avoids spinlocks completely, putting both 392 * counters into a single atomic, and updating that atomic using 393 * atomic_add (in the receive path, when receiving fresh credits), 394 * and using atomic_cmpxchg when updating the two counters. 395 */ 396int rds_ib_send_grab_credits(struct rds_ib_connection *ic, 397 u32 wanted, u32 *adv_credits, int need_posted, int max_posted) 398{ 399 unsigned int avail, posted, got = 0, advertise; 400 long oldval, newval; 401 402 *adv_credits = 0; 403 if (!ic->i_flowctl) 404 return wanted; 405 406try_again: 407 advertise = 0; 408 oldval = newval = atomic_read(&ic->i_credits); 409 posted = IB_GET_POST_CREDITS(oldval); 410 avail = IB_GET_SEND_CREDITS(oldval); 411 412 rdsdebug("wanted=%u credits=%u posted=%u\n", 413 wanted, avail, posted); 414 415 /* The last credit must be used to send a credit update. */ 416 if (avail && !posted) 417 avail--; 418 419 if (avail < wanted) { 420 struct rds_connection *conn = ic->i_cm_id->context; 421 422 /* Oops, there aren't that many credits left! */ 423 set_bit(RDS_LL_SEND_FULL, &conn->c_flags); 424 got = avail; 425 } else { 426 /* Sometimes you get what you want, lalala. */ 427 got = wanted; 428 } 429 newval -= IB_SET_SEND_CREDITS(got); 430 431 /* 432 * If need_posted is non-zero, then the caller wants 433 * the posted regardless of whether any send credits are 434 * available. 435 */ 436 if (posted && (got || need_posted)) { 437 advertise = min_t(unsigned int, posted, max_posted); 438 newval -= IB_SET_POST_CREDITS(advertise); 439 } 440 441 /* Finally bill everything */ 442 if (atomic_cmpxchg(&ic->i_credits, oldval, newval) != oldval) 443 goto try_again; 444 445 *adv_credits = advertise; 446 return got; 447} 448 449void rds_ib_send_add_credits(struct rds_connection *conn, unsigned int credits) 450{ 451 struct rds_ib_connection *ic = conn->c_transport_data; 452 453 if (credits == 0) 454 return; 455 456 rdsdebug("credits=%u current=%u%s\n", 457 credits, 458 IB_GET_SEND_CREDITS(atomic_read(&ic->i_credits)), 459 test_bit(RDS_LL_SEND_FULL, &conn->c_flags) ? ", ll_send_full" : ""); 460 461 atomic_add(IB_SET_SEND_CREDITS(credits), &ic->i_credits); 462 if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags)) 463 queue_delayed_work(rds_wq, &conn->c_send_w, 0); 464 465 WARN_ON(IB_GET_SEND_CREDITS(credits) >= 16384); 466 467 rds_ib_stats_inc(s_ib_rx_credit_updates); 468} 469 470void rds_ib_advertise_credits(struct rds_connection *conn, unsigned int posted) 471{ 472 struct rds_ib_connection *ic = conn->c_transport_data; 473 474 if (posted == 0) 475 return; 476 477 atomic_add(IB_SET_POST_CREDITS(posted), &ic->i_credits); 478 479 /* Decide whether to send an update to the peer now. 480 * If we would send a credit update for every single buffer we 481 * post, we would end up with an ACK storm (ACK arrives, 482 * consumes buffer, we refill the ring, send ACK to remote 483 * advertising the newly posted buffer... ad inf) 484 * 485 * Performance pretty much depends on how often we send 486 * credit updates - too frequent updates mean lots of ACKs. 487 * Too infrequent updates, and the peer will run out of 488 * credits and has to throttle. 489 * For the time being, 16 seems to be a good compromise. 490 */ 491 if (IB_GET_POST_CREDITS(atomic_read(&ic->i_credits)) >= 16) 492 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); 493} 494 495static inline int rds_ib_set_wr_signal_state(struct rds_ib_connection *ic, 496 struct rds_ib_send_work *send, 497 bool notify) 498{ 499 /* 500 * We want to delay signaling completions just enough to get 501 * the batching benefits but not so much that we create dead time 502 * on the wire. 503 */ 504 if (ic->i_unsignaled_wrs-- == 0 || notify) { 505 ic->i_unsignaled_wrs = rds_ib_sysctl_max_unsig_wrs; 506 send->s_wr.send_flags |= IB_SEND_SIGNALED; 507 return 1; 508 } 509 return 0; 510} 511 512/* 513 * This can be called multiple times for a given message. The first time 514 * we see a message we map its scatterlist into the IB device so that 515 * we can provide that mapped address to the IB scatter gather entries 516 * in the IB work requests. We translate the scatterlist into a series 517 * of work requests that fragment the message. These work requests complete 518 * in order so we pass ownership of the message to the completion handler 519 * once we send the final fragment. 520 * 521 * The RDS core uses the c_send_lock to only enter this function once 522 * per connection. This makes sure that the tx ring alloc/unalloc pairs 523 * don't get out of sync and confuse the ring. 524 */ 525int rds_ib_xmit(struct rds_connection *conn, struct rds_message *rm, 526 unsigned int hdr_off, unsigned int sg, unsigned int off) 527{ 528 struct rds_ib_connection *ic = conn->c_transport_data; 529 struct ib_device *dev = ic->i_cm_id->device; 530 struct rds_ib_send_work *send = NULL; 531 struct rds_ib_send_work *first; 532 struct rds_ib_send_work *prev; 533 struct ib_send_wr *failed_wr; 534 struct scatterlist *scat; 535 u32 pos; 536 u32 i; 537 u32 work_alloc; 538 u32 credit_alloc = 0; 539 u32 posted; 540 u32 adv_credits = 0; 541 int send_flags = 0; 542 int bytes_sent = 0; 543 int ret; 544 int flow_controlled = 0; 545 int nr_sig = 0; 546 547 BUG_ON(off % RDS_FRAG_SIZE); 548 BUG_ON(hdr_off != 0 && hdr_off != sizeof(struct rds_header)); 549 550 /* Do not send cong updates to IB loopback */ 551 if (conn->c_loopback 552 && rm->m_inc.i_hdr.h_flags & RDS_FLAG_CONG_BITMAP) { 553 rds_cong_map_updated(conn->c_fcong, ~(u64) 0); 554 scat = &rm->data.op_sg[sg]; 555 ret = max_t(int, RDS_CONG_MAP_BYTES, scat->length); 556 return sizeof(struct rds_header) + ret; 557 } 558 559 /* FIXME we may overallocate here */ 560 if (be32_to_cpu(rm->m_inc.i_hdr.h_len) == 0) 561 i = 1; 562 else 563 i = ceil(be32_to_cpu(rm->m_inc.i_hdr.h_len), RDS_FRAG_SIZE); 564 565 work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos); 566 if (work_alloc == 0) { 567 set_bit(RDS_LL_SEND_FULL, &conn->c_flags); 568 rds_ib_stats_inc(s_ib_tx_ring_full); 569 ret = -ENOMEM; 570 goto out; 571 } 572 573 if (ic->i_flowctl) { 574 credit_alloc = rds_ib_send_grab_credits(ic, work_alloc, &posted, 0, RDS_MAX_ADV_CREDIT); 575 adv_credits += posted; 576 if (credit_alloc < work_alloc) { 577 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - credit_alloc); 578 work_alloc = credit_alloc; 579 flow_controlled = 1; 580 } 581 if (work_alloc == 0) { 582 set_bit(RDS_LL_SEND_FULL, &conn->c_flags); 583 rds_ib_stats_inc(s_ib_tx_throttle); 584 ret = -ENOMEM; 585 goto out; 586 } 587 } 588 589 /* map the message the first time we see it */ 590 if (!ic->i_data_op) { 591 if (rm->data.op_nents) { 592 rm->data.op_count = ib_dma_map_sg(dev, 593 rm->data.op_sg, 594 rm->data.op_nents, 595 DMA_TO_DEVICE); 596 rdsdebug("ic %p mapping rm %p: %d\n", ic, rm, rm->data.op_count); 597 if (rm->data.op_count == 0) { 598 rds_ib_stats_inc(s_ib_tx_sg_mapping_failure); 599 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); 600 ret = -ENOMEM; /* XXX ? */ 601 goto out; 602 } 603 } else { 604 rm->data.op_count = 0; 605 } 606 607 rds_message_addref(rm); 608 ic->i_data_op = &rm->data; 609 610 /* Finalize the header */ 611 if (test_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags)) 612 rm->m_inc.i_hdr.h_flags |= RDS_FLAG_ACK_REQUIRED; 613 if (test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) 614 rm->m_inc.i_hdr.h_flags |= RDS_FLAG_RETRANSMITTED; 615 616 /* If it has a RDMA op, tell the peer we did it. This is 617 * used by the peer to release use-once RDMA MRs. */ 618 if (rm->rdma.op_active) { 619 struct rds_ext_header_rdma ext_hdr; 620 621 ext_hdr.h_rdma_rkey = cpu_to_be32(rm->rdma.op_rkey); 622 rds_message_add_extension(&rm->m_inc.i_hdr, 623 RDS_EXTHDR_RDMA, &ext_hdr, sizeof(ext_hdr)); 624 } 625 if (rm->m_rdma_cookie) { 626 rds_message_add_rdma_dest_extension(&rm->m_inc.i_hdr, 627 rds_rdma_cookie_key(rm->m_rdma_cookie), 628 rds_rdma_cookie_offset(rm->m_rdma_cookie)); 629 } 630 631 /* Note - rds_ib_piggyb_ack clears the ACK_REQUIRED bit, so 632 * we should not do this unless we have a chance of at least 633 * sticking the header into the send ring. Which is why we 634 * should call rds_ib_ring_alloc first. */ 635 rm->m_inc.i_hdr.h_ack = cpu_to_be64(rds_ib_piggyb_ack(ic)); 636 rds_message_make_checksum(&rm->m_inc.i_hdr); 637 638 /* 639 * Update adv_credits since we reset the ACK_REQUIRED bit. 640 */ 641 if (ic->i_flowctl) { 642 rds_ib_send_grab_credits(ic, 0, &posted, 1, RDS_MAX_ADV_CREDIT - adv_credits); 643 adv_credits += posted; 644 BUG_ON(adv_credits > 255); 645 } 646 } 647 648 /* Sometimes you want to put a fence between an RDMA 649 * READ and the following SEND. 650 * We could either do this all the time 651 * or when requested by the user. Right now, we let 652 * the application choose. 653 */ 654 if (rm->rdma.op_active && rm->rdma.op_fence) 655 send_flags = IB_SEND_FENCE; 656 657 /* Each frag gets a header. Msgs may be 0 bytes */ 658 send = &ic->i_sends[pos]; 659 first = send; 660 prev = NULL; 661 scat = &ic->i_data_op->op_sg[sg]; 662 i = 0; 663 do { 664 unsigned int len = 0; 665 666 /* Set up the header */ 667 send->s_wr.send_flags = send_flags; 668 send->s_wr.opcode = IB_WR_SEND; 669 send->s_wr.num_sge = 1; 670 send->s_wr.next = NULL; 671 send->s_queued = jiffies; 672 send->s_op = NULL; 673 674 send->s_sge[0].addr = ic->i_send_hdrs_dma 675 + (pos * sizeof(struct rds_header)); 676 send->s_sge[0].length = sizeof(struct rds_header); 677 678 memcpy(&ic->i_send_hdrs[pos], &rm->m_inc.i_hdr, sizeof(struct rds_header)); 679 680 /* Set up the data, if present */ 681 if (i < work_alloc 682 && scat != &rm->data.op_sg[rm->data.op_count]) { 683 len = min(RDS_FRAG_SIZE, ib_sg_dma_len(dev, scat) - off); 684 send->s_wr.num_sge = 2; 685 686 send->s_sge[1].addr = ib_sg_dma_address(dev, scat) + off; 687 send->s_sge[1].length = len; 688 689 bytes_sent += len; 690 off += len; 691 if (off == ib_sg_dma_len(dev, scat)) { 692 scat++; 693 off = 0; 694 } 695 } 696 697 rds_ib_set_wr_signal_state(ic, send, 0); 698 699 /* 700 * Always signal the last one if we're stopping due to flow control. 701 */ 702 if (ic->i_flowctl && flow_controlled && i == (work_alloc-1)) 703 send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED; 704 705 if (send->s_wr.send_flags & IB_SEND_SIGNALED) 706 nr_sig++; 707 708 rdsdebug("send %p wr %p num_sge %u next %p\n", send, 709 &send->s_wr, send->s_wr.num_sge, send->s_wr.next); 710 711 if (ic->i_flowctl && adv_credits) { 712 struct rds_header *hdr = &ic->i_send_hdrs[pos]; 713 714 /* add credit and redo the header checksum */ 715 hdr->h_credit = adv_credits; 716 rds_message_make_checksum(hdr); 717 adv_credits = 0; 718 rds_ib_stats_inc(s_ib_tx_credit_updates); 719 } 720 721 if (prev) 722 prev->s_wr.next = &send->s_wr; 723 prev = send; 724 725 pos = (pos + 1) % ic->i_send_ring.w_nr; 726 send = &ic->i_sends[pos]; 727 i++; 728 729 } while (i < work_alloc 730 && scat != &rm->data.op_sg[rm->data.op_count]); 731 732 /* Account the RDS header in the number of bytes we sent, but just once. 733 * The caller has no concept of fragmentation. */ 734 if (hdr_off == 0) 735 bytes_sent += sizeof(struct rds_header); 736 737 /* if we finished the message then send completion owns it */ 738 if (scat == &rm->data.op_sg[rm->data.op_count]) { 739 prev->s_op = ic->i_data_op; 740 prev->s_wr.send_flags |= IB_SEND_SOLICITED; 741 ic->i_data_op = NULL; 742 } 743 744 /* Put back wrs & credits we didn't use */ 745 if (i < work_alloc) { 746 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i); 747 work_alloc = i; 748 } 749 if (ic->i_flowctl && i < credit_alloc) 750 rds_ib_send_add_credits(conn, credit_alloc - i); 751 752 if (nr_sig) 753 atomic_add(nr_sig, &ic->i_signaled_sends); 754 755 /* XXX need to worry about failed_wr and partial sends. */ 756 failed_wr = &first->s_wr; 757 ret = ib_post_send(ic->i_cm_id->qp, &first->s_wr, &failed_wr); 758 rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic, 759 first, &first->s_wr, ret, failed_wr); 760 BUG_ON(failed_wr != &first->s_wr); 761 if (ret) { 762 printk(KERN_WARNING "RDS/IB: ib_post_send to %pI4 " 763 "returned %d\n", &conn->c_faddr, ret); 764 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); 765 rds_ib_sub_signaled(ic, nr_sig); 766 if (prev->s_op) { 767 ic->i_data_op = prev->s_op; 768 prev->s_op = NULL; 769 } 770 771 rds_ib_conn_error(ic->conn, "ib_post_send failed\n"); 772 goto out; 773 } 774 775 ret = bytes_sent; 776out: 777 BUG_ON(adv_credits); 778 return ret; 779} 780 781/* 782 * Issue atomic operation. 783 * A simplified version of the rdma case, we always map 1 SG, and 784 * only 8 bytes, for the return value from the atomic operation. 785 */ 786int rds_ib_xmit_atomic(struct rds_connection *conn, struct rm_atomic_op *op) 787{ 788 struct rds_ib_connection *ic = conn->c_transport_data; 789 struct rds_ib_send_work *send = NULL; 790 struct ib_send_wr *failed_wr; 791 struct rds_ib_device *rds_ibdev; 792 u32 pos; 793 u32 work_alloc; 794 int ret; 795 int nr_sig = 0; 796 797 rds_ibdev = ib_get_client_data(ic->i_cm_id->device, &rds_ib_client); 798 799 work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, 1, &pos); 800 if (work_alloc != 1) { 801 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); 802 rds_ib_stats_inc(s_ib_tx_ring_full); 803 ret = -ENOMEM; 804 goto out; 805 } 806 807 /* address of send request in ring */ 808 send = &ic->i_sends[pos]; 809 send->s_queued = jiffies; 810 811 if (op->op_type == RDS_ATOMIC_TYPE_CSWP) { 812 send->s_wr.opcode = IB_WR_MASKED_ATOMIC_CMP_AND_SWP; 813 send->s_wr.wr.atomic.compare_add = op->op_m_cswp.compare; 814 send->s_wr.wr.atomic.swap = op->op_m_cswp.swap; 815 send->s_wr.wr.atomic.compare_add_mask = op->op_m_cswp.compare_mask; 816 send->s_wr.wr.atomic.swap_mask = op->op_m_cswp.swap_mask; 817 } else { /* FADD */ 818 send->s_wr.opcode = IB_WR_MASKED_ATOMIC_FETCH_AND_ADD; 819 send->s_wr.wr.atomic.compare_add = op->op_m_fadd.add; 820 send->s_wr.wr.atomic.swap = 0; 821 send->s_wr.wr.atomic.compare_add_mask = op->op_m_fadd.nocarry_mask; 822 send->s_wr.wr.atomic.swap_mask = 0; 823 } 824 nr_sig = rds_ib_set_wr_signal_state(ic, send, op->op_notify); 825 send->s_wr.num_sge = 1; 826 send->s_wr.next = NULL; 827 send->s_wr.wr.atomic.remote_addr = op->op_remote_addr; 828 send->s_wr.wr.atomic.rkey = op->op_rkey; 829 send->s_op = op; 830 rds_message_addref(container_of(send->s_op, struct rds_message, atomic)); 831 832 /* map 8 byte retval buffer to the device */ 833 ret = ib_dma_map_sg(ic->i_cm_id->device, op->op_sg, 1, DMA_FROM_DEVICE); 834 rdsdebug("ic %p mapping atomic op %p. mapped %d pg\n", ic, op, ret); 835 if (ret != 1) { 836 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); 837 rds_ib_stats_inc(s_ib_tx_sg_mapping_failure); 838 ret = -ENOMEM; /* XXX ? */ 839 goto out; 840 } 841 842 /* Convert our struct scatterlist to struct ib_sge */ 843 send->s_sge[0].addr = ib_sg_dma_address(ic->i_cm_id->device, op->op_sg); 844 send->s_sge[0].length = ib_sg_dma_len(ic->i_cm_id->device, op->op_sg); 845 send->s_sge[0].lkey = ic->i_mr->lkey; 846 847 rdsdebug("rva %Lx rpa %Lx len %u\n", op->op_remote_addr, 848 send->s_sge[0].addr, send->s_sge[0].length); 849 850 if (nr_sig) 851 atomic_add(nr_sig, &ic->i_signaled_sends); 852 853 failed_wr = &send->s_wr; 854 ret = ib_post_send(ic->i_cm_id->qp, &send->s_wr, &failed_wr); 855 rdsdebug("ic %p send %p (wr %p) ret %d wr %p\n", ic, 856 send, &send->s_wr, ret, failed_wr); 857 BUG_ON(failed_wr != &send->s_wr); 858 if (ret) { 859 printk(KERN_WARNING "RDS/IB: atomic ib_post_send to %pI4 " 860 "returned %d\n", &conn->c_faddr, ret); 861 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); 862 rds_ib_sub_signaled(ic, nr_sig); 863 goto out; 864 } 865 866 if (unlikely(failed_wr != &send->s_wr)) { 867 printk(KERN_WARNING "RDS/IB: atomic ib_post_send() rc=%d, but failed_wqe updated!\n", ret); 868 BUG_ON(failed_wr != &send->s_wr); 869 } 870 871out: 872 return ret; 873} 874 875int rds_ib_xmit_rdma(struct rds_connection *conn, struct rm_rdma_op *op) 876{ 877 struct rds_ib_connection *ic = conn->c_transport_data; 878 struct rds_ib_send_work *send = NULL; 879 struct rds_ib_send_work *first; 880 struct rds_ib_send_work *prev; 881 struct ib_send_wr *failed_wr; 882 struct scatterlist *scat; 883 unsigned long len; 884 u64 remote_addr = op->op_remote_addr; 885 u32 max_sge = ic->rds_ibdev->max_sge; 886 u32 pos; 887 u32 work_alloc; 888 u32 i; 889 u32 j; 890 int sent; 891 int ret; 892 int num_sge; 893 int nr_sig = 0; 894 895 /* map the op the first time we see it */ 896 if (!op->op_mapped) { 897 op->op_count = ib_dma_map_sg(ic->i_cm_id->device, 898 op->op_sg, op->op_nents, (op->op_write) ? 899 DMA_TO_DEVICE : DMA_FROM_DEVICE); 900 rdsdebug("ic %p mapping op %p: %d\n", ic, op, op->op_count); 901 if (op->op_count == 0) { 902 rds_ib_stats_inc(s_ib_tx_sg_mapping_failure); 903 ret = -ENOMEM; /* XXX ? */ 904 goto out; 905 } 906 907 op->op_mapped = 1; 908 } 909 910 /* 911 * Instead of knowing how to return a partial rdma read/write we insist that there 912 * be enough work requests to send the entire message. 913 */ 914 i = ceil(op->op_count, max_sge); 915 916 work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos); 917 if (work_alloc != i) { 918 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); 919 rds_ib_stats_inc(s_ib_tx_ring_full); 920 ret = -ENOMEM; 921 goto out; 922 } 923 924 send = &ic->i_sends[pos]; 925 first = send; 926 prev = NULL; 927 scat = &op->op_sg[0]; 928 sent = 0; 929 num_sge = op->op_count; 930 931 for (i = 0; i < work_alloc && scat != &op->op_sg[op->op_count]; i++) { 932 send->s_wr.send_flags = 0; 933 send->s_queued = jiffies; 934 send->s_op = NULL; 935 936 nr_sig += rds_ib_set_wr_signal_state(ic, send, op->op_notify); 937 938 send->s_wr.opcode = op->op_write ? IB_WR_RDMA_WRITE : IB_WR_RDMA_READ; 939 send->s_wr.wr.rdma.remote_addr = remote_addr; 940 send->s_wr.wr.rdma.rkey = op->op_rkey; 941 942 if (num_sge > max_sge) { 943 send->s_wr.num_sge = max_sge; 944 num_sge -= max_sge; 945 } else { 946 send->s_wr.num_sge = num_sge; 947 } 948 949 send->s_wr.next = NULL; 950 951 if (prev) 952 prev->s_wr.next = &send->s_wr; 953 954 for (j = 0; j < send->s_wr.num_sge && scat != &op->op_sg[op->op_count]; j++) { 955 len = ib_sg_dma_len(ic->i_cm_id->device, scat); 956 send->s_sge[j].addr = 957 ib_sg_dma_address(ic->i_cm_id->device, scat); 958 send->s_sge[j].length = len; 959 send->s_sge[j].lkey = ic->i_mr->lkey; 960 961 sent += len; 962 rdsdebug("ic %p sent %d remote_addr %llu\n", ic, sent, remote_addr); 963 964 remote_addr += len; 965 scat++; 966 } 967 968 rdsdebug("send %p wr %p num_sge %u next %p\n", send, 969 &send->s_wr, send->s_wr.num_sge, send->s_wr.next); 970 971 prev = send; 972 if (++send == &ic->i_sends[ic->i_send_ring.w_nr]) 973 send = ic->i_sends; 974 } 975 976 /* give a reference to the last op */ 977 if (scat == &op->op_sg[op->op_count]) { 978 prev->s_op = op; 979 rds_message_addref(container_of(op, struct rds_message, rdma)); 980 } 981 982 if (i < work_alloc) { 983 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i); 984 work_alloc = i; 985 } 986 987 if (nr_sig) 988 atomic_add(nr_sig, &ic->i_signaled_sends); 989 990 failed_wr = &first->s_wr; 991 ret = ib_post_send(ic->i_cm_id->qp, &first->s_wr, &failed_wr); 992 rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic, 993 first, &first->s_wr, ret, failed_wr); 994 BUG_ON(failed_wr != &first->s_wr); 995 if (ret) { 996 printk(KERN_WARNING "RDS/IB: rdma ib_post_send to %pI4 " 997 "returned %d\n", &conn->c_faddr, ret); 998 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); 999 rds_ib_sub_signaled(ic, nr_sig); 1000 goto out; 1001 } 1002 1003 if (unlikely(failed_wr != &first->s_wr)) { 1004 printk(KERN_WARNING "RDS/IB: ib_post_send() rc=%d, but failed_wqe updated!\n", ret); 1005 BUG_ON(failed_wr != &first->s_wr); 1006 } 1007 1008 1009out: 1010 return ret; 1011} 1012 1013void rds_ib_xmit_complete(struct rds_connection *conn) 1014{ 1015 struct rds_ib_connection *ic = conn->c_transport_data; 1016 1017 /* We may have a pending ACK or window update we were unable 1018 * to send previously (due to flow control). Try again. */ 1019 rds_ib_attempt_ack(ic); 1020} 1021