1/* 2 * Copyright (c) 2006, 2019 Oracle and/or its affiliates. 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_single_path.h" 40#include "rds.h" 41#include "ib.h" 42#include "ib_mr.h" 43 44/* 45 * Convert IB-specific error message to RDS error message and call core 46 * completion handler. 47 */ 48static void rds_ib_send_complete(struct rds_message *rm, 49 int wc_status, 50 void (*complete)(struct rds_message *rm, int status)) 51{ 52 int notify_status; 53 54 switch (wc_status) { 55 case IB_WC_WR_FLUSH_ERR: 56 return; 57 58 case IB_WC_SUCCESS: 59 notify_status = RDS_RDMA_SUCCESS; 60 break; 61 62 case IB_WC_REM_ACCESS_ERR: 63 notify_status = RDS_RDMA_REMOTE_ERROR; 64 break; 65 66 default: 67 notify_status = RDS_RDMA_OTHER_ERROR; 68 break; 69 } 70 complete(rm, notify_status); 71} 72 73static void rds_ib_send_unmap_data(struct rds_ib_connection *ic, 74 struct rm_data_op *op, 75 int wc_status) 76{ 77 if (op->op_nents) 78 ib_dma_unmap_sg(ic->i_cm_id->device, 79 op->op_sg, op->op_nents, 80 DMA_TO_DEVICE); 81} 82 83static void rds_ib_send_unmap_rdma(struct rds_ib_connection *ic, 84 struct rm_rdma_op *op, 85 int wc_status) 86{ 87 if (op->op_mapped) { 88 ib_dma_unmap_sg(ic->i_cm_id->device, 89 op->op_sg, op->op_nents, 90 op->op_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE); 91 op->op_mapped = 0; 92 } 93 94 /* If the user asked for a completion notification on this 95 * message, we can implement three different semantics: 96 * 1. Notify when we received the ACK on the RDS message 97 * that was queued with the RDMA. This provides reliable 98 * notification of RDMA status at the expense of a one-way 99 * packet delay. 100 * 2. Notify when the IB stack gives us the completion event for 101 * the RDMA operation. 102 * 3. Notify when the IB stack gives us the completion event for 103 * the accompanying RDS messages. 104 * Here, we implement approach #3. To implement approach #2, 105 * we would need to take an event for the rdma WR. To implement #1, 106 * don't call rds_rdma_send_complete at all, and fall back to the notify 107 * handling in the ACK processing code. 108 * 109 * Note: There's no need to explicitly sync any RDMA buffers using 110 * ib_dma_sync_sg_for_cpu - the completion for the RDMA 111 * operation itself unmapped the RDMA buffers, which takes care 112 * of synching. 113 */ 114 rds_ib_send_complete(container_of(op, struct rds_message, rdma), 115 wc_status, rds_rdma_send_complete); 116 117 if (op->op_write) 118 rds_stats_add(s_send_rdma_bytes, op->op_bytes); 119 else 120 rds_stats_add(s_recv_rdma_bytes, op->op_bytes); 121} 122 123static void rds_ib_send_unmap_atomic(struct rds_ib_connection *ic, 124 struct rm_atomic_op *op, 125 int wc_status) 126{ 127 /* unmap atomic recvbuf */ 128 if (op->op_mapped) { 129 ib_dma_unmap_sg(ic->i_cm_id->device, op->op_sg, 1, 130 DMA_FROM_DEVICE); 131 op->op_mapped = 0; 132 } 133 134 rds_ib_send_complete(container_of(op, struct rds_message, atomic), 135 wc_status, rds_atomic_send_complete); 136 137 if (op->op_type == RDS_ATOMIC_TYPE_CSWP) 138 rds_ib_stats_inc(s_ib_atomic_cswp); 139 else 140 rds_ib_stats_inc(s_ib_atomic_fadd); 141} 142 143/* 144 * Unmap the resources associated with a struct send_work. 145 * 146 * Returns the rm for no good reason other than it is unobtainable 147 * other than by switching on wr.opcode, currently, and the caller, 148 * the event handler, needs it. 149 */ 150static struct rds_message *rds_ib_send_unmap_op(struct rds_ib_connection *ic, 151 struct rds_ib_send_work *send, 152 int wc_status) 153{ 154 struct rds_message *rm = NULL; 155 156 /* In the error case, wc.opcode sometimes contains garbage */ 157 switch (send->s_wr.opcode) { 158 case IB_WR_SEND: 159 if (send->s_op) { 160 rm = container_of(send->s_op, struct rds_message, data); 161 rds_ib_send_unmap_data(ic, send->s_op, wc_status); 162 } 163 break; 164 case IB_WR_RDMA_WRITE: 165 case IB_WR_RDMA_READ: 166 if (send->s_op) { 167 rm = container_of(send->s_op, struct rds_message, rdma); 168 rds_ib_send_unmap_rdma(ic, send->s_op, wc_status); 169 } 170 break; 171 case IB_WR_ATOMIC_FETCH_AND_ADD: 172 case IB_WR_ATOMIC_CMP_AND_SWP: 173 if (send->s_op) { 174 rm = container_of(send->s_op, struct rds_message, atomic); 175 rds_ib_send_unmap_atomic(ic, send->s_op, wc_status); 176 } 177 break; 178 default: 179 printk_ratelimited(KERN_NOTICE 180 "RDS/IB: %s: unexpected opcode 0x%x in WR!\n", 181 __func__, send->s_wr.opcode); 182 break; 183 } 184 185 send->s_wr.opcode = 0xdead; 186 187 return rm; 188} 189 190void rds_ib_send_init_ring(struct rds_ib_connection *ic) 191{ 192 struct rds_ib_send_work *send; 193 u32 i; 194 195 for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) { 196 struct ib_sge *sge; 197 198 send->s_op = NULL; 199 200 send->s_wr.wr_id = i; 201 send->s_wr.sg_list = send->s_sge; 202 send->s_wr.ex.imm_data = 0; 203 204 sge = &send->s_sge[0]; 205 sge->addr = ic->i_send_hdrs_dma[i]; 206 207 sge->length = sizeof(struct rds_header); 208 sge->lkey = ic->i_pd->local_dma_lkey; 209 210 send->s_sge[1].lkey = ic->i_pd->local_dma_lkey; 211 } 212} 213 214void rds_ib_send_clear_ring(struct rds_ib_connection *ic) 215{ 216 struct rds_ib_send_work *send; 217 u32 i; 218 219 for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) { 220 if (send->s_op && send->s_wr.opcode != 0xdead) 221 rds_ib_send_unmap_op(ic, send, IB_WC_WR_FLUSH_ERR); 222 } 223} 224 225/* 226 * The only fast path caller always has a non-zero nr, so we don't 227 * bother testing nr before performing the atomic sub. 228 */ 229static void rds_ib_sub_signaled(struct rds_ib_connection *ic, int nr) 230{ 231 if ((atomic_sub_return(nr, &ic->i_signaled_sends) == 0) && 232 waitqueue_active(&rds_ib_ring_empty_wait)) 233 wake_up(&rds_ib_ring_empty_wait); 234 BUG_ON(atomic_read(&ic->i_signaled_sends) < 0); 235} 236 237/* 238 * The _oldest/_free ring operations here race cleanly with the alloc/unalloc 239 * operations performed in the send path. As the sender allocs and potentially 240 * unallocs the next free entry in the ring it doesn't alter which is 241 * the next to be freed, which is what this is concerned with. 242 */ 243void rds_ib_send_cqe_handler(struct rds_ib_connection *ic, struct ib_wc *wc) 244{ 245 struct rds_message *rm = NULL; 246 struct rds_connection *conn = ic->conn; 247 struct rds_ib_send_work *send; 248 u32 completed; 249 u32 oldest; 250 u32 i = 0; 251 int nr_sig = 0; 252 253 254 rdsdebug("wc wr_id 0x%llx status %u (%s) byte_len %u imm_data %u\n", 255 (unsigned long long)wc->wr_id, wc->status, 256 ib_wc_status_msg(wc->status), wc->byte_len, 257 be32_to_cpu(wc->ex.imm_data)); 258 rds_ib_stats_inc(s_ib_tx_cq_event); 259 260 if (wc->wr_id == RDS_IB_ACK_WR_ID) { 261 if (time_after(jiffies, ic->i_ack_queued + HZ / 2)) 262 rds_ib_stats_inc(s_ib_tx_stalled); 263 rds_ib_ack_send_complete(ic); 264 return; 265 } 266 267 oldest = rds_ib_ring_oldest(&ic->i_send_ring); 268 269 completed = rds_ib_ring_completed(&ic->i_send_ring, wc->wr_id, oldest); 270 271 for (i = 0; i < completed; i++) { 272 send = &ic->i_sends[oldest]; 273 if (send->s_wr.send_flags & IB_SEND_SIGNALED) 274 nr_sig++; 275 276 rm = rds_ib_send_unmap_op(ic, send, wc->status); 277 278 if (time_after(jiffies, send->s_queued + HZ / 2)) 279 rds_ib_stats_inc(s_ib_tx_stalled); 280 281 if (send->s_op) { 282 if (send->s_op == rm->m_final_op) { 283 /* If anyone waited for this message to get 284 * flushed out, wake them up now 285 */ 286 rds_message_unmapped(rm); 287 } 288 rds_message_put(rm); 289 send->s_op = NULL; 290 } 291 292 oldest = (oldest + 1) % ic->i_send_ring.w_nr; 293 } 294 295 rds_ib_ring_free(&ic->i_send_ring, completed); 296 rds_ib_sub_signaled(ic, nr_sig); 297 298 if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags) || 299 test_bit(0, &conn->c_map_queued)) 300 queue_delayed_work(rds_wq, &conn->c_send_w, 0); 301 302 /* We expect errors as the qp is drained during shutdown */ 303 if (wc->status != IB_WC_SUCCESS && rds_conn_up(conn)) { 304 rds_ib_conn_error(conn, "send completion on <%pI6c,%pI6c,%d> had status %u (%s), vendor err 0x%x, disconnecting and reconnecting\n", 305 &conn->c_laddr, &conn->c_faddr, 306 conn->c_tos, wc->status, 307 ib_wc_status_msg(wc->status), wc->vendor_err); 308 } 309} 310 311/* 312 * This is the main function for allocating credits when sending 313 * messages. 314 * 315 * Conceptually, we have two counters: 316 * - send credits: this tells us how many WRs we're allowed 317 * to submit without overruning the receiver's queue. For 318 * each SEND WR we post, we decrement this by one. 319 * 320 * - posted credits: this tells us how many WRs we recently 321 * posted to the receive queue. This value is transferred 322 * to the peer as a "credit update" in a RDS header field. 323 * Every time we transmit credits to the peer, we subtract 324 * the amount of transferred credits from this counter. 325 * 326 * It is essential that we avoid situations where both sides have 327 * exhausted their send credits, and are unable to send new credits 328 * to the peer. We achieve this by requiring that we send at least 329 * one credit update to the peer before exhausting our credits. 330 * When new credits arrive, we subtract one credit that is withheld 331 * until we've posted new buffers and are ready to transmit these 332 * credits (see rds_ib_send_add_credits below). 333 * 334 * The RDS send code is essentially single-threaded; rds_send_xmit 335 * sets RDS_IN_XMIT to ensure exclusive access to the send ring. 336 * However, the ACK sending code is independent and can race with 337 * message SENDs. 338 * 339 * In the send path, we need to update the counters for send credits 340 * and the counter of posted buffers atomically - when we use the 341 * last available credit, we cannot allow another thread to race us 342 * and grab the posted credits counter. Hence, we have to use a 343 * spinlock to protect the credit counter, or use atomics. 344 * 345 * Spinlocks shared between the send and the receive path are bad, 346 * because they create unnecessary delays. An early implementation 347 * using a spinlock showed a 5% degradation in throughput at some 348 * loads. 349 * 350 * This implementation avoids spinlocks completely, putting both 351 * counters into a single atomic, and updating that atomic using 352 * atomic_add (in the receive path, when receiving fresh credits), 353 * and using atomic_cmpxchg when updating the two counters. 354 */ 355int rds_ib_send_grab_credits(struct rds_ib_connection *ic, 356 u32 wanted, u32 *adv_credits, int need_posted, int max_posted) 357{ 358 unsigned int avail, posted, got = 0, advertise; 359 long oldval, newval; 360 361 *adv_credits = 0; 362 if (!ic->i_flowctl) 363 return wanted; 364 365try_again: 366 advertise = 0; 367 oldval = newval = atomic_read(&ic->i_credits); 368 posted = IB_GET_POST_CREDITS(oldval); 369 avail = IB_GET_SEND_CREDITS(oldval); 370 371 rdsdebug("wanted=%u credits=%u posted=%u\n", 372 wanted, avail, posted); 373 374 /* The last credit must be used to send a credit update. */ 375 if (avail && !posted) 376 avail--; 377 378 if (avail < wanted) { 379 struct rds_connection *conn = ic->i_cm_id->context; 380 381 /* Oops, there aren't that many credits left! */ 382 set_bit(RDS_LL_SEND_FULL, &conn->c_flags); 383 got = avail; 384 } else { 385 /* Sometimes you get what you want, lalala. */ 386 got = wanted; 387 } 388 newval -= IB_SET_SEND_CREDITS(got); 389 390 /* 391 * If need_posted is non-zero, then the caller wants 392 * the posted regardless of whether any send credits are 393 * available. 394 */ 395 if (posted && (got || need_posted)) { 396 advertise = min_t(unsigned int, posted, max_posted); 397 newval -= IB_SET_POST_CREDITS(advertise); 398 } 399 400 /* Finally bill everything */ 401 if (atomic_cmpxchg(&ic->i_credits, oldval, newval) != oldval) 402 goto try_again; 403 404 *adv_credits = advertise; 405 return got; 406} 407 408void rds_ib_send_add_credits(struct rds_connection *conn, unsigned int credits) 409{ 410 struct rds_ib_connection *ic = conn->c_transport_data; 411 412 if (credits == 0) 413 return; 414 415 rdsdebug("credits=%u current=%u%s\n", 416 credits, 417 IB_GET_SEND_CREDITS(atomic_read(&ic->i_credits)), 418 test_bit(RDS_LL_SEND_FULL, &conn->c_flags) ? ", ll_send_full" : ""); 419 420 atomic_add(IB_SET_SEND_CREDITS(credits), &ic->i_credits); 421 if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags)) 422 queue_delayed_work(rds_wq, &conn->c_send_w, 0); 423 424 WARN_ON(IB_GET_SEND_CREDITS(credits) >= 16384); 425 426 rds_ib_stats_inc(s_ib_rx_credit_updates); 427} 428 429void rds_ib_advertise_credits(struct rds_connection *conn, unsigned int posted) 430{ 431 struct rds_ib_connection *ic = conn->c_transport_data; 432 433 if (posted == 0) 434 return; 435 436 atomic_add(IB_SET_POST_CREDITS(posted), &ic->i_credits); 437 438 /* Decide whether to send an update to the peer now. 439 * If we would send a credit update for every single buffer we 440 * post, we would end up with an ACK storm (ACK arrives, 441 * consumes buffer, we refill the ring, send ACK to remote 442 * advertising the newly posted buffer... ad inf) 443 * 444 * Performance pretty much depends on how often we send 445 * credit updates - too frequent updates mean lots of ACKs. 446 * Too infrequent updates, and the peer will run out of 447 * credits and has to throttle. 448 * For the time being, 16 seems to be a good compromise. 449 */ 450 if (IB_GET_POST_CREDITS(atomic_read(&ic->i_credits)) >= 16) 451 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); 452} 453 454static inline int rds_ib_set_wr_signal_state(struct rds_ib_connection *ic, 455 struct rds_ib_send_work *send, 456 bool notify) 457{ 458 /* 459 * We want to delay signaling completions just enough to get 460 * the batching benefits but not so much that we create dead time 461 * on the wire. 462 */ 463 if (ic->i_unsignaled_wrs-- == 0 || notify) { 464 ic->i_unsignaled_wrs = rds_ib_sysctl_max_unsig_wrs; 465 send->s_wr.send_flags |= IB_SEND_SIGNALED; 466 return 1; 467 } 468 return 0; 469} 470 471/* 472 * This can be called multiple times for a given message. The first time 473 * we see a message we map its scatterlist into the IB device so that 474 * we can provide that mapped address to the IB scatter gather entries 475 * in the IB work requests. We translate the scatterlist into a series 476 * of work requests that fragment the message. These work requests complete 477 * in order so we pass ownership of the message to the completion handler 478 * once we send the final fragment. 479 * 480 * The RDS core uses the c_send_lock to only enter this function once 481 * per connection. This makes sure that the tx ring alloc/unalloc pairs 482 * don't get out of sync and confuse the ring. 483 */ 484int rds_ib_xmit(struct rds_connection *conn, struct rds_message *rm, 485 unsigned int hdr_off, unsigned int sg, unsigned int off) 486{ 487 struct rds_ib_connection *ic = conn->c_transport_data; 488 struct ib_device *dev = ic->i_cm_id->device; 489 struct rds_ib_send_work *send = NULL; 490 struct rds_ib_send_work *first; 491 struct rds_ib_send_work *prev; 492 const struct ib_send_wr *failed_wr; 493 struct scatterlist *scat; 494 u32 pos; 495 u32 i; 496 u32 work_alloc; 497 u32 credit_alloc = 0; 498 u32 posted; 499 u32 adv_credits = 0; 500 int send_flags = 0; 501 int bytes_sent = 0; 502 int ret; 503 int flow_controlled = 0; 504 int nr_sig = 0; 505 506 BUG_ON(off % RDS_FRAG_SIZE); 507 BUG_ON(hdr_off != 0 && hdr_off != sizeof(struct rds_header)); 508 509 /* Do not send cong updates to IB loopback */ 510 if (conn->c_loopback 511 && rm->m_inc.i_hdr.h_flags & RDS_FLAG_CONG_BITMAP) { 512 rds_cong_map_updated(conn->c_fcong, ~(u64) 0); 513 scat = &rm->data.op_sg[sg]; 514 ret = max_t(int, RDS_CONG_MAP_BYTES, scat->length); 515 return sizeof(struct rds_header) + ret; 516 } 517 518 /* FIXME we may overallocate here */ 519 if (be32_to_cpu(rm->m_inc.i_hdr.h_len) == 0) 520 i = 1; 521 else 522 i = DIV_ROUND_UP(be32_to_cpu(rm->m_inc.i_hdr.h_len), RDS_FRAG_SIZE); 523 524 work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos); 525 if (work_alloc == 0) { 526 set_bit(RDS_LL_SEND_FULL, &conn->c_flags); 527 rds_ib_stats_inc(s_ib_tx_ring_full); 528 ret = -ENOMEM; 529 goto out; 530 } 531 532 if (ic->i_flowctl) { 533 credit_alloc = rds_ib_send_grab_credits(ic, work_alloc, &posted, 0, RDS_MAX_ADV_CREDIT); 534 adv_credits += posted; 535 if (credit_alloc < work_alloc) { 536 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - credit_alloc); 537 work_alloc = credit_alloc; 538 flow_controlled = 1; 539 } 540 if (work_alloc == 0) { 541 set_bit(RDS_LL_SEND_FULL, &conn->c_flags); 542 rds_ib_stats_inc(s_ib_tx_throttle); 543 ret = -ENOMEM; 544 goto out; 545 } 546 } 547 548 /* map the message the first time we see it */ 549 if (!ic->i_data_op) { 550 if (rm->data.op_nents) { 551 rm->data.op_count = ib_dma_map_sg(dev, 552 rm->data.op_sg, 553 rm->data.op_nents, 554 DMA_TO_DEVICE); 555 rdsdebug("ic %p mapping rm %p: %d\n", ic, rm, rm->data.op_count); 556 if (rm->data.op_count == 0) { 557 rds_ib_stats_inc(s_ib_tx_sg_mapping_failure); 558 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); 559 ret = -ENOMEM; /* XXX ? */ 560 goto out; 561 } 562 } else { 563 rm->data.op_count = 0; 564 } 565 566 rds_message_addref(rm); 567 rm->data.op_dmasg = 0; 568 rm->data.op_dmaoff = 0; 569 ic->i_data_op = &rm->data; 570 571 /* Finalize the header */ 572 if (test_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags)) 573 rm->m_inc.i_hdr.h_flags |= RDS_FLAG_ACK_REQUIRED; 574 if (test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) 575 rm->m_inc.i_hdr.h_flags |= RDS_FLAG_RETRANSMITTED; 576 577 /* If it has a RDMA op, tell the peer we did it. This is 578 * used by the peer to release use-once RDMA MRs. */ 579 if (rm->rdma.op_active) { 580 struct rds_ext_header_rdma ext_hdr; 581 582 ext_hdr.h_rdma_rkey = cpu_to_be32(rm->rdma.op_rkey); 583 rds_message_add_extension(&rm->m_inc.i_hdr, 584 RDS_EXTHDR_RDMA, &ext_hdr, sizeof(ext_hdr)); 585 } 586 if (rm->m_rdma_cookie) { 587 rds_message_add_rdma_dest_extension(&rm->m_inc.i_hdr, 588 rds_rdma_cookie_key(rm->m_rdma_cookie), 589 rds_rdma_cookie_offset(rm->m_rdma_cookie)); 590 } 591 592 /* Note - rds_ib_piggyb_ack clears the ACK_REQUIRED bit, so 593 * we should not do this unless we have a chance of at least 594 * sticking the header into the send ring. Which is why we 595 * should call rds_ib_ring_alloc first. */ 596 rm->m_inc.i_hdr.h_ack = cpu_to_be64(rds_ib_piggyb_ack(ic)); 597 rds_message_make_checksum(&rm->m_inc.i_hdr); 598 599 /* 600 * Update adv_credits since we reset the ACK_REQUIRED bit. 601 */ 602 if (ic->i_flowctl) { 603 rds_ib_send_grab_credits(ic, 0, &posted, 1, RDS_MAX_ADV_CREDIT - adv_credits); 604 adv_credits += posted; 605 BUG_ON(adv_credits > 255); 606 } 607 } 608 609 /* Sometimes you want to put a fence between an RDMA 610 * READ and the following SEND. 611 * We could either do this all the time 612 * or when requested by the user. Right now, we let 613 * the application choose. 614 */ 615 if (rm->rdma.op_active && rm->rdma.op_fence) 616 send_flags = IB_SEND_FENCE; 617 618 /* Each frag gets a header. Msgs may be 0 bytes */ 619 send = &ic->i_sends[pos]; 620 first = send; 621 prev = NULL; 622 scat = &ic->i_data_op->op_sg[rm->data.op_dmasg]; 623 i = 0; 624 do { 625 unsigned int len = 0; 626 627 /* Set up the header */ 628 send->s_wr.send_flags = send_flags; 629 send->s_wr.opcode = IB_WR_SEND; 630 send->s_wr.num_sge = 1; 631 send->s_wr.next = NULL; 632 send->s_queued = jiffies; 633 send->s_op = NULL; 634 635 send->s_sge[0].addr = ic->i_send_hdrs_dma[pos]; 636 637 send->s_sge[0].length = sizeof(struct rds_header); 638 send->s_sge[0].lkey = ic->i_pd->local_dma_lkey; 639 640 ib_dma_sync_single_for_cpu(ic->rds_ibdev->dev, 641 ic->i_send_hdrs_dma[pos], 642 sizeof(struct rds_header), 643 DMA_TO_DEVICE); 644 memcpy(ic->i_send_hdrs[pos], &rm->m_inc.i_hdr, 645 sizeof(struct rds_header)); 646 647 648 /* Set up the data, if present */ 649 if (i < work_alloc 650 && scat != &rm->data.op_sg[rm->data.op_count]) { 651 len = min(RDS_FRAG_SIZE, 652 sg_dma_len(scat) - rm->data.op_dmaoff); 653 send->s_wr.num_sge = 2; 654 655 send->s_sge[1].addr = sg_dma_address(scat); 656 send->s_sge[1].addr += rm->data.op_dmaoff; 657 send->s_sge[1].length = len; 658 send->s_sge[1].lkey = ic->i_pd->local_dma_lkey; 659 660 bytes_sent += len; 661 rm->data.op_dmaoff += len; 662 if (rm->data.op_dmaoff == sg_dma_len(scat)) { 663 scat++; 664 rm->data.op_dmasg++; 665 rm->data.op_dmaoff = 0; 666 } 667 } 668 669 rds_ib_set_wr_signal_state(ic, send, false); 670 671 /* 672 * Always signal the last one if we're stopping due to flow control. 673 */ 674 if (ic->i_flowctl && flow_controlled && i == (work_alloc - 1)) { 675 rds_ib_set_wr_signal_state(ic, send, true); 676 send->s_wr.send_flags |= IB_SEND_SOLICITED; 677 } 678 679 if (send->s_wr.send_flags & IB_SEND_SIGNALED) 680 nr_sig++; 681 682 rdsdebug("send %p wr %p num_sge %u next %p\n", send, 683 &send->s_wr, send->s_wr.num_sge, send->s_wr.next); 684 685 if (ic->i_flowctl && adv_credits) { 686 struct rds_header *hdr = ic->i_send_hdrs[pos]; 687 688 /* add credit and redo the header checksum */ 689 hdr->h_credit = adv_credits; 690 rds_message_make_checksum(hdr); 691 adv_credits = 0; 692 rds_ib_stats_inc(s_ib_tx_credit_updates); 693 } 694 ib_dma_sync_single_for_device(ic->rds_ibdev->dev, 695 ic->i_send_hdrs_dma[pos], 696 sizeof(struct rds_header), 697 DMA_TO_DEVICE); 698 699 if (prev) 700 prev->s_wr.next = &send->s_wr; 701 prev = send; 702 703 pos = (pos + 1) % ic->i_send_ring.w_nr; 704 send = &ic->i_sends[pos]; 705 i++; 706 707 } while (i < work_alloc 708 && scat != &rm->data.op_sg[rm->data.op_count]); 709 710 /* Account the RDS header in the number of bytes we sent, but just once. 711 * The caller has no concept of fragmentation. */ 712 if (hdr_off == 0) 713 bytes_sent += sizeof(struct rds_header); 714 715 /* if we finished the message then send completion owns it */ 716 if (scat == &rm->data.op_sg[rm->data.op_count]) { 717 prev->s_op = ic->i_data_op; 718 prev->s_wr.send_flags |= IB_SEND_SOLICITED; 719 if (!(prev->s_wr.send_flags & IB_SEND_SIGNALED)) 720 nr_sig += rds_ib_set_wr_signal_state(ic, prev, true); 721 ic->i_data_op = NULL; 722 } 723 724 /* Put back wrs & credits we didn't use */ 725 if (i < work_alloc) { 726 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i); 727 work_alloc = i; 728 } 729 if (ic->i_flowctl && i < credit_alloc) 730 rds_ib_send_add_credits(conn, credit_alloc - i); 731 732 if (nr_sig) 733 atomic_add(nr_sig, &ic->i_signaled_sends); 734 735 /* XXX need to worry about failed_wr and partial sends. */ 736 failed_wr = &first->s_wr; 737 ret = ib_post_send(ic->i_cm_id->qp, &first->s_wr, &failed_wr); 738 rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic, 739 first, &first->s_wr, ret, failed_wr); 740 BUG_ON(failed_wr != &first->s_wr); 741 if (ret) { 742 printk(KERN_WARNING "RDS/IB: ib_post_send to %pI6c " 743 "returned %d\n", &conn->c_faddr, ret); 744 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); 745 rds_ib_sub_signaled(ic, nr_sig); 746 if (prev->s_op) { 747 ic->i_data_op = prev->s_op; 748 prev->s_op = NULL; 749 } 750 751 rds_ib_conn_error(ic->conn, "ib_post_send failed\n"); 752 goto out; 753 } 754 755 ret = bytes_sent; 756out: 757 BUG_ON(adv_credits); 758 return ret; 759} 760 761/* 762 * Issue atomic operation. 763 * A simplified version of the rdma case, we always map 1 SG, and 764 * only 8 bytes, for the return value from the atomic operation. 765 */ 766int rds_ib_xmit_atomic(struct rds_connection *conn, struct rm_atomic_op *op) 767{ 768 struct rds_ib_connection *ic = conn->c_transport_data; 769 struct rds_ib_send_work *send = NULL; 770 const struct ib_send_wr *failed_wr; 771 u32 pos; 772 u32 work_alloc; 773 int ret; 774 int nr_sig = 0; 775 776 work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, 1, &pos); 777 if (work_alloc != 1) { 778 rds_ib_stats_inc(s_ib_tx_ring_full); 779 ret = -ENOMEM; 780 goto out; 781 } 782 783 /* address of send request in ring */ 784 send = &ic->i_sends[pos]; 785 send->s_queued = jiffies; 786 787 if (op->op_type == RDS_ATOMIC_TYPE_CSWP) { 788 send->s_atomic_wr.wr.opcode = IB_WR_MASKED_ATOMIC_CMP_AND_SWP; 789 send->s_atomic_wr.compare_add = op->op_m_cswp.compare; 790 send->s_atomic_wr.swap = op->op_m_cswp.swap; 791 send->s_atomic_wr.compare_add_mask = op->op_m_cswp.compare_mask; 792 send->s_atomic_wr.swap_mask = op->op_m_cswp.swap_mask; 793 } else { /* FADD */ 794 send->s_atomic_wr.wr.opcode = IB_WR_MASKED_ATOMIC_FETCH_AND_ADD; 795 send->s_atomic_wr.compare_add = op->op_m_fadd.add; 796 send->s_atomic_wr.swap = 0; 797 send->s_atomic_wr.compare_add_mask = op->op_m_fadd.nocarry_mask; 798 send->s_atomic_wr.swap_mask = 0; 799 } 800 send->s_wr.send_flags = 0; 801 nr_sig = rds_ib_set_wr_signal_state(ic, send, op->op_notify); 802 send->s_atomic_wr.wr.num_sge = 1; 803 send->s_atomic_wr.wr.next = NULL; 804 send->s_atomic_wr.remote_addr = op->op_remote_addr; 805 send->s_atomic_wr.rkey = op->op_rkey; 806 send->s_op = op; 807 rds_message_addref(container_of(send->s_op, struct rds_message, atomic)); 808 809 /* map 8 byte retval buffer to the device */ 810 ret = ib_dma_map_sg(ic->i_cm_id->device, op->op_sg, 1, DMA_FROM_DEVICE); 811 rdsdebug("ic %p mapping atomic op %p. mapped %d pg\n", ic, op, ret); 812 if (ret != 1) { 813 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); 814 rds_ib_stats_inc(s_ib_tx_sg_mapping_failure); 815 ret = -ENOMEM; /* XXX ? */ 816 goto out; 817 } 818 819 /* Convert our struct scatterlist to struct ib_sge */ 820 send->s_sge[0].addr = sg_dma_address(op->op_sg); 821 send->s_sge[0].length = sg_dma_len(op->op_sg); 822 send->s_sge[0].lkey = ic->i_pd->local_dma_lkey; 823 824 rdsdebug("rva %Lx rpa %Lx len %u\n", op->op_remote_addr, 825 send->s_sge[0].addr, send->s_sge[0].length); 826 827 if (nr_sig) 828 atomic_add(nr_sig, &ic->i_signaled_sends); 829 830 failed_wr = &send->s_atomic_wr.wr; 831 ret = ib_post_send(ic->i_cm_id->qp, &send->s_atomic_wr.wr, &failed_wr); 832 rdsdebug("ic %p send %p (wr %p) ret %d wr %p\n", ic, 833 send, &send->s_atomic_wr, ret, failed_wr); 834 BUG_ON(failed_wr != &send->s_atomic_wr.wr); 835 if (ret) { 836 printk(KERN_WARNING "RDS/IB: atomic ib_post_send to %pI6c " 837 "returned %d\n", &conn->c_faddr, ret); 838 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); 839 rds_ib_sub_signaled(ic, nr_sig); 840 goto out; 841 } 842 843 if (unlikely(failed_wr != &send->s_atomic_wr.wr)) { 844 printk(KERN_WARNING "RDS/IB: atomic ib_post_send() rc=%d, but failed_wqe updated!\n", ret); 845 BUG_ON(failed_wr != &send->s_atomic_wr.wr); 846 } 847 848out: 849 return ret; 850} 851 852int rds_ib_xmit_rdma(struct rds_connection *conn, struct rm_rdma_op *op) 853{ 854 struct rds_ib_connection *ic = conn->c_transport_data; 855 struct rds_ib_send_work *send = NULL; 856 struct rds_ib_send_work *first; 857 struct rds_ib_send_work *prev; 858 const struct ib_send_wr *failed_wr; 859 struct scatterlist *scat; 860 unsigned long len; 861 u64 remote_addr = op->op_remote_addr; 862 u32 max_sge = ic->rds_ibdev->max_sge; 863 u32 pos; 864 u32 work_alloc; 865 u32 i; 866 u32 j; 867 int sent; 868 int ret; 869 int num_sge; 870 int nr_sig = 0; 871 u64 odp_addr = op->op_odp_addr; 872 u32 odp_lkey = 0; 873 874 /* map the op the first time we see it */ 875 if (!op->op_odp_mr) { 876 if (!op->op_mapped) { 877 op->op_count = 878 ib_dma_map_sg(ic->i_cm_id->device, op->op_sg, 879 op->op_nents, 880 (op->op_write) ? DMA_TO_DEVICE : 881 DMA_FROM_DEVICE); 882 rdsdebug("ic %p mapping op %p: %d\n", ic, op, 883 op->op_count); 884 if (op->op_count == 0) { 885 rds_ib_stats_inc(s_ib_tx_sg_mapping_failure); 886 ret = -ENOMEM; /* XXX ? */ 887 goto out; 888 } 889 op->op_mapped = 1; 890 } 891 } else { 892 op->op_count = op->op_nents; 893 odp_lkey = rds_ib_get_lkey(op->op_odp_mr->r_trans_private); 894 } 895 896 /* 897 * Instead of knowing how to return a partial rdma read/write we insist that there 898 * be enough work requests to send the entire message. 899 */ 900 i = DIV_ROUND_UP(op->op_count, max_sge); 901 902 work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos); 903 if (work_alloc != i) { 904 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); 905 rds_ib_stats_inc(s_ib_tx_ring_full); 906 ret = -ENOMEM; 907 goto out; 908 } 909 910 send = &ic->i_sends[pos]; 911 first = send; 912 prev = NULL; 913 scat = &op->op_sg[0]; 914 sent = 0; 915 num_sge = op->op_count; 916 917 for (i = 0; i < work_alloc && scat != &op->op_sg[op->op_count]; i++) { 918 send->s_wr.send_flags = 0; 919 send->s_queued = jiffies; 920 send->s_op = NULL; 921 922 if (!op->op_notify) 923 nr_sig += rds_ib_set_wr_signal_state(ic, send, 924 op->op_notify); 925 926 send->s_wr.opcode = op->op_write ? IB_WR_RDMA_WRITE : IB_WR_RDMA_READ; 927 send->s_rdma_wr.remote_addr = remote_addr; 928 send->s_rdma_wr.rkey = op->op_rkey; 929 930 if (num_sge > max_sge) { 931 send->s_rdma_wr.wr.num_sge = max_sge; 932 num_sge -= max_sge; 933 } else { 934 send->s_rdma_wr.wr.num_sge = num_sge; 935 } 936 937 send->s_rdma_wr.wr.next = NULL; 938 939 if (prev) 940 prev->s_rdma_wr.wr.next = &send->s_rdma_wr.wr; 941 942 for (j = 0; j < send->s_rdma_wr.wr.num_sge && 943 scat != &op->op_sg[op->op_count]; j++) { 944 len = sg_dma_len(scat); 945 if (!op->op_odp_mr) { 946 send->s_sge[j].addr = sg_dma_address(scat); 947 send->s_sge[j].lkey = ic->i_pd->local_dma_lkey; 948 } else { 949 send->s_sge[j].addr = odp_addr; 950 send->s_sge[j].lkey = odp_lkey; 951 } 952 send->s_sge[j].length = len; 953 954 sent += len; 955 rdsdebug("ic %p sent %d remote_addr %llu\n", ic, sent, remote_addr); 956 957 remote_addr += len; 958 odp_addr += len; 959 scat++; 960 } 961 962 rdsdebug("send %p wr %p num_sge %u next %p\n", send, 963 &send->s_rdma_wr.wr, 964 send->s_rdma_wr.wr.num_sge, 965 send->s_rdma_wr.wr.next); 966 967 prev = send; 968 if (++send == &ic->i_sends[ic->i_send_ring.w_nr]) 969 send = ic->i_sends; 970 } 971 972 /* give a reference to the last op */ 973 if (scat == &op->op_sg[op->op_count]) { 974 prev->s_op = op; 975 rds_message_addref(container_of(op, struct rds_message, rdma)); 976 } 977 978 if (i < work_alloc) { 979 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i); 980 work_alloc = i; 981 } 982 983 if (nr_sig) 984 atomic_add(nr_sig, &ic->i_signaled_sends); 985 986 failed_wr = &first->s_rdma_wr.wr; 987 ret = ib_post_send(ic->i_cm_id->qp, &first->s_rdma_wr.wr, &failed_wr); 988 rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic, 989 first, &first->s_rdma_wr.wr, ret, failed_wr); 990 BUG_ON(failed_wr != &first->s_rdma_wr.wr); 991 if (ret) { 992 printk(KERN_WARNING "RDS/IB: rdma ib_post_send to %pI6c " 993 "returned %d\n", &conn->c_faddr, ret); 994 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); 995 rds_ib_sub_signaled(ic, nr_sig); 996 goto out; 997 } 998 999 if (unlikely(failed_wr != &first->s_rdma_wr.wr)) { 1000 printk(KERN_WARNING "RDS/IB: ib_post_send() rc=%d, but failed_wqe updated!\n", ret); 1001 BUG_ON(failed_wr != &first->s_rdma_wr.wr); 1002 } 1003 1004 1005out: 1006 return ret; 1007} 1008 1009void rds_ib_xmit_path_complete(struct rds_conn_path *cp) 1010{ 1011 struct rds_connection *conn = cp->cp_conn; 1012 struct rds_ib_connection *ic = conn->c_transport_data; 1013 1014 /* We may have a pending ACK or window update we were unable 1015 * to send previously (due to flow control). Try again. */ 1016 rds_ib_attempt_ack(ic); 1017} 1018