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 */ 48 static 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 73 static 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 83 static 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 } 122 123 static 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 */ 150 static 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 } 189 190 void 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 } 213 214 void 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 */ 229 static 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 */ 243 void 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 nr_sig = 0; 298 299 if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags) || 300 test_bit(0, &conn->c_map_queued)) 301 queue_delayed_work(rds_wq, &conn->c_send_w, 0); 302 303 /* We expect errors as the qp is drained during shutdown */ 304 if (wc->status != IB_WC_SUCCESS && rds_conn_up(conn)) { 305 rds_ib_conn_error(conn, "send completion on <%pI6c,%pI6c,%d> had status %u (%s), vendor err 0x%x, disconnecting and reconnecting\n", 306 &conn->c_laddr, &conn->c_faddr, 307 conn->c_tos, wc->status, 308 ib_wc_status_msg(wc->status), wc->vendor_err); 309 } 310 } 311 312 /* 313 * This is the main function for allocating credits when sending 314 * messages. 315 * 316 * Conceptually, we have two counters: 317 * - send credits: this tells us how many WRs we're allowed 318 * to submit without overruning the receiver's queue. For 319 * each SEND WR we post, we decrement this by one. 320 * 321 * - posted credits: this tells us how many WRs we recently 322 * posted to the receive queue. This value is transferred 323 * to the peer as a "credit update" in a RDS header field. 324 * Every time we transmit credits to the peer, we subtract 325 * the amount of transferred credits from this counter. 326 * 327 * It is essential that we avoid situations where both sides have 328 * exhausted their send credits, and are unable to send new credits 329 * to the peer. We achieve this by requiring that we send at least 330 * one credit update to the peer before exhausting our credits. 331 * When new credits arrive, we subtract one credit that is withheld 332 * until we've posted new buffers and are ready to transmit these 333 * credits (see rds_ib_send_add_credits below). 334 * 335 * The RDS send code is essentially single-threaded; rds_send_xmit 336 * sets RDS_IN_XMIT to ensure exclusive access to the send ring. 337 * However, the ACK sending code is independent and can race with 338 * message SENDs. 339 * 340 * In the send path, we need to update the counters for send credits 341 * and the counter of posted buffers atomically - when we use the 342 * last available credit, we cannot allow another thread to race us 343 * and grab the posted credits counter. Hence, we have to use a 344 * spinlock to protect the credit counter, or use atomics. 345 * 346 * Spinlocks shared between the send and the receive path are bad, 347 * because they create unnecessary delays. An early implementation 348 * using a spinlock showed a 5% degradation in throughput at some 349 * loads. 350 * 351 * This implementation avoids spinlocks completely, putting both 352 * counters into a single atomic, and updating that atomic using 353 * atomic_add (in the receive path, when receiving fresh credits), 354 * and using atomic_cmpxchg when updating the two counters. 355 */ 356 int rds_ib_send_grab_credits(struct rds_ib_connection *ic, 357 u32 wanted, u32 *adv_credits, int need_posted, int max_posted) 358 { 359 unsigned int avail, posted, got = 0, advertise; 360 long oldval, newval; 361 362 *adv_credits = 0; 363 if (!ic->i_flowctl) 364 return wanted; 365 366 try_again: 367 advertise = 0; 368 oldval = newval = atomic_read(&ic->i_credits); 369 posted = IB_GET_POST_CREDITS(oldval); 370 avail = IB_GET_SEND_CREDITS(oldval); 371 372 rdsdebug("wanted=%u credits=%u posted=%u\n", 373 wanted, avail, posted); 374 375 /* The last credit must be used to send a credit update. */ 376 if (avail && !posted) 377 avail--; 378 379 if (avail < wanted) { 380 struct rds_connection *conn = ic->i_cm_id->context; 381 382 /* Oops, there aren't that many credits left! */ 383 set_bit(RDS_LL_SEND_FULL, &conn->c_flags); 384 got = avail; 385 } else { 386 /* Sometimes you get what you want, lalala. */ 387 got = wanted; 388 } 389 newval -= IB_SET_SEND_CREDITS(got); 390 391 /* 392 * If need_posted is non-zero, then the caller wants 393 * the posted regardless of whether any send credits are 394 * available. 395 */ 396 if (posted && (got || need_posted)) { 397 advertise = min_t(unsigned int, posted, max_posted); 398 newval -= IB_SET_POST_CREDITS(advertise); 399 } 400 401 /* Finally bill everything */ 402 if (atomic_cmpxchg(&ic->i_credits, oldval, newval) != oldval) 403 goto try_again; 404 405 *adv_credits = advertise; 406 return got; 407 } 408 409 void rds_ib_send_add_credits(struct rds_connection *conn, unsigned int credits) 410 { 411 struct rds_ib_connection *ic = conn->c_transport_data; 412 413 if (credits == 0) 414 return; 415 416 rdsdebug("credits=%u current=%u%s\n", 417 credits, 418 IB_GET_SEND_CREDITS(atomic_read(&ic->i_credits)), 419 test_bit(RDS_LL_SEND_FULL, &conn->c_flags) ? ", ll_send_full" : ""); 420 421 atomic_add(IB_SET_SEND_CREDITS(credits), &ic->i_credits); 422 if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags)) 423 queue_delayed_work(rds_wq, &conn->c_send_w, 0); 424 425 WARN_ON(IB_GET_SEND_CREDITS(credits) >= 16384); 426 427 rds_ib_stats_inc(s_ib_rx_credit_updates); 428 } 429 430 void rds_ib_advertise_credits(struct rds_connection *conn, unsigned int posted) 431 { 432 struct rds_ib_connection *ic = conn->c_transport_data; 433 434 if (posted == 0) 435 return; 436 437 atomic_add(IB_SET_POST_CREDITS(posted), &ic->i_credits); 438 439 /* Decide whether to send an update to the peer now. 440 * If we would send a credit update for every single buffer we 441 * post, we would end up with an ACK storm (ACK arrives, 442 * consumes buffer, we refill the ring, send ACK to remote 443 * advertising the newly posted buffer... ad inf) 444 * 445 * Performance pretty much depends on how often we send 446 * credit updates - too frequent updates mean lots of ACKs. 447 * Too infrequent updates, and the peer will run out of 448 * credits and has to throttle. 449 * For the time being, 16 seems to be a good compromise. 450 */ 451 if (IB_GET_POST_CREDITS(atomic_read(&ic->i_credits)) >= 16) 452 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); 453 } 454 455 static inline int rds_ib_set_wr_signal_state(struct rds_ib_connection *ic, 456 struct rds_ib_send_work *send, 457 bool notify) 458 { 459 /* 460 * We want to delay signaling completions just enough to get 461 * the batching benefits but not so much that we create dead time 462 * on the wire. 463 */ 464 if (ic->i_unsignaled_wrs-- == 0 || notify) { 465 ic->i_unsignaled_wrs = rds_ib_sysctl_max_unsig_wrs; 466 send->s_wr.send_flags |= IB_SEND_SIGNALED; 467 return 1; 468 } 469 return 0; 470 } 471 472 /* 473 * This can be called multiple times for a given message. The first time 474 * we see a message we map its scatterlist into the IB device so that 475 * we can provide that mapped address to the IB scatter gather entries 476 * in the IB work requests. We translate the scatterlist into a series 477 * of work requests that fragment the message. These work requests complete 478 * in order so we pass ownership of the message to the completion handler 479 * once we send the final fragment. 480 * 481 * The RDS core uses the c_send_lock to only enter this function once 482 * per connection. This makes sure that the tx ring alloc/unalloc pairs 483 * don't get out of sync and confuse the ring. 484 */ 485 int rds_ib_xmit(struct rds_connection *conn, struct rds_message *rm, 486 unsigned int hdr_off, unsigned int sg, unsigned int off) 487 { 488 struct rds_ib_connection *ic = conn->c_transport_data; 489 struct ib_device *dev = ic->i_cm_id->device; 490 struct rds_ib_send_work *send = NULL; 491 struct rds_ib_send_work *first; 492 struct rds_ib_send_work *prev; 493 const struct ib_send_wr *failed_wr; 494 struct scatterlist *scat; 495 u32 pos; 496 u32 i; 497 u32 work_alloc; 498 u32 credit_alloc = 0; 499 u32 posted; 500 u32 adv_credits = 0; 501 int send_flags = 0; 502 int bytes_sent = 0; 503 int ret; 504 int flow_controlled = 0; 505 int nr_sig = 0; 506 507 BUG_ON(off % RDS_FRAG_SIZE); 508 BUG_ON(hdr_off != 0 && hdr_off != sizeof(struct rds_header)); 509 510 /* Do not send cong updates to IB loopback */ 511 if (conn->c_loopback 512 && rm->m_inc.i_hdr.h_flags & RDS_FLAG_CONG_BITMAP) { 513 rds_cong_map_updated(conn->c_fcong, ~(u64) 0); 514 scat = &rm->data.op_sg[sg]; 515 ret = max_t(int, RDS_CONG_MAP_BYTES, scat->length); 516 return sizeof(struct rds_header) + ret; 517 } 518 519 /* FIXME we may overallocate here */ 520 if (be32_to_cpu(rm->m_inc.i_hdr.h_len) == 0) 521 i = 1; 522 else 523 i = DIV_ROUND_UP(be32_to_cpu(rm->m_inc.i_hdr.h_len), RDS_FRAG_SIZE); 524 525 work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos); 526 if (work_alloc == 0) { 527 set_bit(RDS_LL_SEND_FULL, &conn->c_flags); 528 rds_ib_stats_inc(s_ib_tx_ring_full); 529 ret = -ENOMEM; 530 goto out; 531 } 532 533 if (ic->i_flowctl) { 534 credit_alloc = rds_ib_send_grab_credits(ic, work_alloc, &posted, 0, RDS_MAX_ADV_CREDIT); 535 adv_credits += posted; 536 if (credit_alloc < work_alloc) { 537 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - credit_alloc); 538 work_alloc = credit_alloc; 539 flow_controlled = 1; 540 } 541 if (work_alloc == 0) { 542 set_bit(RDS_LL_SEND_FULL, &conn->c_flags); 543 rds_ib_stats_inc(s_ib_tx_throttle); 544 ret = -ENOMEM; 545 goto out; 546 } 547 } 548 549 /* map the message the first time we see it */ 550 if (!ic->i_data_op) { 551 if (rm->data.op_nents) { 552 rm->data.op_count = ib_dma_map_sg(dev, 553 rm->data.op_sg, 554 rm->data.op_nents, 555 DMA_TO_DEVICE); 556 rdsdebug("ic %p mapping rm %p: %d\n", ic, rm, rm->data.op_count); 557 if (rm->data.op_count == 0) { 558 rds_ib_stats_inc(s_ib_tx_sg_mapping_failure); 559 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); 560 ret = -ENOMEM; /* XXX ? */ 561 goto out; 562 } 563 } else { 564 rm->data.op_count = 0; 565 } 566 567 rds_message_addref(rm); 568 rm->data.op_dmasg = 0; 569 rm->data.op_dmaoff = 0; 570 ic->i_data_op = &rm->data; 571 572 /* Finalize the header */ 573 if (test_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags)) 574 rm->m_inc.i_hdr.h_flags |= RDS_FLAG_ACK_REQUIRED; 575 if (test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) 576 rm->m_inc.i_hdr.h_flags |= RDS_FLAG_RETRANSMITTED; 577 578 /* If it has a RDMA op, tell the peer we did it. This is 579 * used by the peer to release use-once RDMA MRs. */ 580 if (rm->rdma.op_active) { 581 struct rds_ext_header_rdma ext_hdr; 582 583 ext_hdr.h_rdma_rkey = cpu_to_be32(rm->rdma.op_rkey); 584 rds_message_add_extension(&rm->m_inc.i_hdr, 585 RDS_EXTHDR_RDMA, &ext_hdr, sizeof(ext_hdr)); 586 } 587 if (rm->m_rdma_cookie) { 588 rds_message_add_rdma_dest_extension(&rm->m_inc.i_hdr, 589 rds_rdma_cookie_key(rm->m_rdma_cookie), 590 rds_rdma_cookie_offset(rm->m_rdma_cookie)); 591 } 592 593 /* Note - rds_ib_piggyb_ack clears the ACK_REQUIRED bit, so 594 * we should not do this unless we have a chance of at least 595 * sticking the header into the send ring. Which is why we 596 * should call rds_ib_ring_alloc first. */ 597 rm->m_inc.i_hdr.h_ack = cpu_to_be64(rds_ib_piggyb_ack(ic)); 598 rds_message_make_checksum(&rm->m_inc.i_hdr); 599 600 /* 601 * Update adv_credits since we reset the ACK_REQUIRED bit. 602 */ 603 if (ic->i_flowctl) { 604 rds_ib_send_grab_credits(ic, 0, &posted, 1, RDS_MAX_ADV_CREDIT - adv_credits); 605 adv_credits += posted; 606 BUG_ON(adv_credits > 255); 607 } 608 } 609 610 /* Sometimes you want to put a fence between an RDMA 611 * READ and the following SEND. 612 * We could either do this all the time 613 * or when requested by the user. Right now, we let 614 * the application choose. 615 */ 616 if (rm->rdma.op_active && rm->rdma.op_fence) 617 send_flags = IB_SEND_FENCE; 618 619 /* Each frag gets a header. Msgs may be 0 bytes */ 620 send = &ic->i_sends[pos]; 621 first = send; 622 prev = NULL; 623 scat = &ic->i_data_op->op_sg[rm->data.op_dmasg]; 624 i = 0; 625 do { 626 unsigned int len = 0; 627 628 /* Set up the header */ 629 send->s_wr.send_flags = send_flags; 630 send->s_wr.opcode = IB_WR_SEND; 631 send->s_wr.num_sge = 1; 632 send->s_wr.next = NULL; 633 send->s_queued = jiffies; 634 send->s_op = NULL; 635 636 send->s_sge[0].addr = ic->i_send_hdrs_dma[pos]; 637 638 send->s_sge[0].length = sizeof(struct rds_header); 639 send->s_sge[0].lkey = ic->i_pd->local_dma_lkey; 640 641 memcpy(ic->i_send_hdrs[pos], &rm->m_inc.i_hdr, 642 sizeof(struct rds_header)); 643 644 645 /* Set up the data, if present */ 646 if (i < work_alloc 647 && scat != &rm->data.op_sg[rm->data.op_count]) { 648 len = min(RDS_FRAG_SIZE, 649 sg_dma_len(scat) - rm->data.op_dmaoff); 650 send->s_wr.num_sge = 2; 651 652 send->s_sge[1].addr = sg_dma_address(scat); 653 send->s_sge[1].addr += rm->data.op_dmaoff; 654 send->s_sge[1].length = len; 655 send->s_sge[1].lkey = ic->i_pd->local_dma_lkey; 656 657 bytes_sent += len; 658 rm->data.op_dmaoff += len; 659 if (rm->data.op_dmaoff == sg_dma_len(scat)) { 660 scat++; 661 rm->data.op_dmasg++; 662 rm->data.op_dmaoff = 0; 663 } 664 } 665 666 rds_ib_set_wr_signal_state(ic, send, false); 667 668 /* 669 * Always signal the last one if we're stopping due to flow control. 670 */ 671 if (ic->i_flowctl && flow_controlled && i == (work_alloc - 1)) { 672 rds_ib_set_wr_signal_state(ic, send, true); 673 send->s_wr.send_flags |= IB_SEND_SOLICITED; 674 } 675 676 if (send->s_wr.send_flags & IB_SEND_SIGNALED) 677 nr_sig++; 678 679 rdsdebug("send %p wr %p num_sge %u next %p\n", send, 680 &send->s_wr, send->s_wr.num_sge, send->s_wr.next); 681 682 if (ic->i_flowctl && adv_credits) { 683 struct rds_header *hdr = ic->i_send_hdrs[pos]; 684 685 /* add credit and redo the header checksum */ 686 hdr->h_credit = adv_credits; 687 rds_message_make_checksum(hdr); 688 adv_credits = 0; 689 rds_ib_stats_inc(s_ib_tx_credit_updates); 690 } 691 692 if (prev) 693 prev->s_wr.next = &send->s_wr; 694 prev = send; 695 696 pos = (pos + 1) % ic->i_send_ring.w_nr; 697 send = &ic->i_sends[pos]; 698 i++; 699 700 } while (i < work_alloc 701 && scat != &rm->data.op_sg[rm->data.op_count]); 702 703 /* Account the RDS header in the number of bytes we sent, but just once. 704 * The caller has no concept of fragmentation. */ 705 if (hdr_off == 0) 706 bytes_sent += sizeof(struct rds_header); 707 708 /* if we finished the message then send completion owns it */ 709 if (scat == &rm->data.op_sg[rm->data.op_count]) { 710 prev->s_op = ic->i_data_op; 711 prev->s_wr.send_flags |= IB_SEND_SOLICITED; 712 if (!(prev->s_wr.send_flags & IB_SEND_SIGNALED)) 713 nr_sig += rds_ib_set_wr_signal_state(ic, prev, true); 714 ic->i_data_op = NULL; 715 } 716 717 /* Put back wrs & credits we didn't use */ 718 if (i < work_alloc) { 719 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i); 720 work_alloc = i; 721 } 722 if (ic->i_flowctl && i < credit_alloc) 723 rds_ib_send_add_credits(conn, credit_alloc - i); 724 725 if (nr_sig) 726 atomic_add(nr_sig, &ic->i_signaled_sends); 727 728 /* XXX need to worry about failed_wr and partial sends. */ 729 failed_wr = &first->s_wr; 730 ret = ib_post_send(ic->i_cm_id->qp, &first->s_wr, &failed_wr); 731 rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic, 732 first, &first->s_wr, ret, failed_wr); 733 BUG_ON(failed_wr != &first->s_wr); 734 if (ret) { 735 printk(KERN_WARNING "RDS/IB: ib_post_send to %pI6c " 736 "returned %d\n", &conn->c_faddr, ret); 737 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); 738 rds_ib_sub_signaled(ic, nr_sig); 739 if (prev->s_op) { 740 ic->i_data_op = prev->s_op; 741 prev->s_op = NULL; 742 } 743 744 rds_ib_conn_error(ic->conn, "ib_post_send failed\n"); 745 goto out; 746 } 747 748 ret = bytes_sent; 749 out: 750 BUG_ON(adv_credits); 751 return ret; 752 } 753 754 /* 755 * Issue atomic operation. 756 * A simplified version of the rdma case, we always map 1 SG, and 757 * only 8 bytes, for the return value from the atomic operation. 758 */ 759 int rds_ib_xmit_atomic(struct rds_connection *conn, struct rm_atomic_op *op) 760 { 761 struct rds_ib_connection *ic = conn->c_transport_data; 762 struct rds_ib_send_work *send = NULL; 763 const struct ib_send_wr *failed_wr; 764 u32 pos; 765 u32 work_alloc; 766 int ret; 767 int nr_sig = 0; 768 769 work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, 1, &pos); 770 if (work_alloc != 1) { 771 rds_ib_stats_inc(s_ib_tx_ring_full); 772 ret = -ENOMEM; 773 goto out; 774 } 775 776 /* address of send request in ring */ 777 send = &ic->i_sends[pos]; 778 send->s_queued = jiffies; 779 780 if (op->op_type == RDS_ATOMIC_TYPE_CSWP) { 781 send->s_atomic_wr.wr.opcode = IB_WR_MASKED_ATOMIC_CMP_AND_SWP; 782 send->s_atomic_wr.compare_add = op->op_m_cswp.compare; 783 send->s_atomic_wr.swap = op->op_m_cswp.swap; 784 send->s_atomic_wr.compare_add_mask = op->op_m_cswp.compare_mask; 785 send->s_atomic_wr.swap_mask = op->op_m_cswp.swap_mask; 786 } else { /* FADD */ 787 send->s_atomic_wr.wr.opcode = IB_WR_MASKED_ATOMIC_FETCH_AND_ADD; 788 send->s_atomic_wr.compare_add = op->op_m_fadd.add; 789 send->s_atomic_wr.swap = 0; 790 send->s_atomic_wr.compare_add_mask = op->op_m_fadd.nocarry_mask; 791 send->s_atomic_wr.swap_mask = 0; 792 } 793 send->s_wr.send_flags = 0; 794 nr_sig = rds_ib_set_wr_signal_state(ic, send, op->op_notify); 795 send->s_atomic_wr.wr.num_sge = 1; 796 send->s_atomic_wr.wr.next = NULL; 797 send->s_atomic_wr.remote_addr = op->op_remote_addr; 798 send->s_atomic_wr.rkey = op->op_rkey; 799 send->s_op = op; 800 rds_message_addref(container_of(send->s_op, struct rds_message, atomic)); 801 802 /* map 8 byte retval buffer to the device */ 803 ret = ib_dma_map_sg(ic->i_cm_id->device, op->op_sg, 1, DMA_FROM_DEVICE); 804 rdsdebug("ic %p mapping atomic op %p. mapped %d pg\n", ic, op, ret); 805 if (ret != 1) { 806 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); 807 rds_ib_stats_inc(s_ib_tx_sg_mapping_failure); 808 ret = -ENOMEM; /* XXX ? */ 809 goto out; 810 } 811 812 /* Convert our struct scatterlist to struct ib_sge */ 813 send->s_sge[0].addr = sg_dma_address(op->op_sg); 814 send->s_sge[0].length = sg_dma_len(op->op_sg); 815 send->s_sge[0].lkey = ic->i_pd->local_dma_lkey; 816 817 rdsdebug("rva %Lx rpa %Lx len %u\n", op->op_remote_addr, 818 send->s_sge[0].addr, send->s_sge[0].length); 819 820 if (nr_sig) 821 atomic_add(nr_sig, &ic->i_signaled_sends); 822 823 failed_wr = &send->s_atomic_wr.wr; 824 ret = ib_post_send(ic->i_cm_id->qp, &send->s_atomic_wr.wr, &failed_wr); 825 rdsdebug("ic %p send %p (wr %p) ret %d wr %p\n", ic, 826 send, &send->s_atomic_wr, ret, failed_wr); 827 BUG_ON(failed_wr != &send->s_atomic_wr.wr); 828 if (ret) { 829 printk(KERN_WARNING "RDS/IB: atomic ib_post_send to %pI6c " 830 "returned %d\n", &conn->c_faddr, ret); 831 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); 832 rds_ib_sub_signaled(ic, nr_sig); 833 goto out; 834 } 835 836 if (unlikely(failed_wr != &send->s_atomic_wr.wr)) { 837 printk(KERN_WARNING "RDS/IB: atomic ib_post_send() rc=%d, but failed_wqe updated!\n", ret); 838 BUG_ON(failed_wr != &send->s_atomic_wr.wr); 839 } 840 841 out: 842 return ret; 843 } 844 845 int rds_ib_xmit_rdma(struct rds_connection *conn, struct rm_rdma_op *op) 846 { 847 struct rds_ib_connection *ic = conn->c_transport_data; 848 struct rds_ib_send_work *send = NULL; 849 struct rds_ib_send_work *first; 850 struct rds_ib_send_work *prev; 851 const struct ib_send_wr *failed_wr; 852 struct scatterlist *scat; 853 unsigned long len; 854 u64 remote_addr = op->op_remote_addr; 855 u32 max_sge = ic->rds_ibdev->max_sge; 856 u32 pos; 857 u32 work_alloc; 858 u32 i; 859 u32 j; 860 int sent; 861 int ret; 862 int num_sge; 863 int nr_sig = 0; 864 u64 odp_addr = op->op_odp_addr; 865 u32 odp_lkey = 0; 866 867 /* map the op the first time we see it */ 868 if (!op->op_odp_mr) { 869 if (!op->op_mapped) { 870 op->op_count = 871 ib_dma_map_sg(ic->i_cm_id->device, op->op_sg, 872 op->op_nents, 873 (op->op_write) ? DMA_TO_DEVICE : 874 DMA_FROM_DEVICE); 875 rdsdebug("ic %p mapping op %p: %d\n", ic, op, 876 op->op_count); 877 if (op->op_count == 0) { 878 rds_ib_stats_inc(s_ib_tx_sg_mapping_failure); 879 ret = -ENOMEM; /* XXX ? */ 880 goto out; 881 } 882 op->op_mapped = 1; 883 } 884 } else { 885 op->op_count = op->op_nents; 886 odp_lkey = rds_ib_get_lkey(op->op_odp_mr->r_trans_private); 887 } 888 889 /* 890 * Instead of knowing how to return a partial rdma read/write we insist that there 891 * be enough work requests to send the entire message. 892 */ 893 i = DIV_ROUND_UP(op->op_count, max_sge); 894 895 work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos); 896 if (work_alloc != i) { 897 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); 898 rds_ib_stats_inc(s_ib_tx_ring_full); 899 ret = -ENOMEM; 900 goto out; 901 } 902 903 send = &ic->i_sends[pos]; 904 first = send; 905 prev = NULL; 906 scat = &op->op_sg[0]; 907 sent = 0; 908 num_sge = op->op_count; 909 910 for (i = 0; i < work_alloc && scat != &op->op_sg[op->op_count]; i++) { 911 send->s_wr.send_flags = 0; 912 send->s_queued = jiffies; 913 send->s_op = NULL; 914 915 if (!op->op_notify) 916 nr_sig += rds_ib_set_wr_signal_state(ic, send, 917 op->op_notify); 918 919 send->s_wr.opcode = op->op_write ? IB_WR_RDMA_WRITE : IB_WR_RDMA_READ; 920 send->s_rdma_wr.remote_addr = remote_addr; 921 send->s_rdma_wr.rkey = op->op_rkey; 922 923 if (num_sge > max_sge) { 924 send->s_rdma_wr.wr.num_sge = max_sge; 925 num_sge -= max_sge; 926 } else { 927 send->s_rdma_wr.wr.num_sge = num_sge; 928 } 929 930 send->s_rdma_wr.wr.next = NULL; 931 932 if (prev) 933 prev->s_rdma_wr.wr.next = &send->s_rdma_wr.wr; 934 935 for (j = 0; j < send->s_rdma_wr.wr.num_sge && 936 scat != &op->op_sg[op->op_count]; j++) { 937 len = sg_dma_len(scat); 938 if (!op->op_odp_mr) { 939 send->s_sge[j].addr = sg_dma_address(scat); 940 send->s_sge[j].lkey = ic->i_pd->local_dma_lkey; 941 } else { 942 send->s_sge[j].addr = odp_addr; 943 send->s_sge[j].lkey = odp_lkey; 944 } 945 send->s_sge[j].length = len; 946 947 sent += len; 948 rdsdebug("ic %p sent %d remote_addr %llu\n", ic, sent, remote_addr); 949 950 remote_addr += len; 951 odp_addr += len; 952 scat++; 953 } 954 955 rdsdebug("send %p wr %p num_sge %u next %p\n", send, 956 &send->s_rdma_wr.wr, 957 send->s_rdma_wr.wr.num_sge, 958 send->s_rdma_wr.wr.next); 959 960 prev = send; 961 if (++send == &ic->i_sends[ic->i_send_ring.w_nr]) 962 send = ic->i_sends; 963 } 964 965 /* give a reference to the last op */ 966 if (scat == &op->op_sg[op->op_count]) { 967 prev->s_op = op; 968 rds_message_addref(container_of(op, struct rds_message, rdma)); 969 } 970 971 if (i < work_alloc) { 972 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i); 973 work_alloc = i; 974 } 975 976 if (nr_sig) 977 atomic_add(nr_sig, &ic->i_signaled_sends); 978 979 failed_wr = &first->s_rdma_wr.wr; 980 ret = ib_post_send(ic->i_cm_id->qp, &first->s_rdma_wr.wr, &failed_wr); 981 rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic, 982 first, &first->s_rdma_wr.wr, ret, failed_wr); 983 BUG_ON(failed_wr != &first->s_rdma_wr.wr); 984 if (ret) { 985 printk(KERN_WARNING "RDS/IB: rdma ib_post_send to %pI6c " 986 "returned %d\n", &conn->c_faddr, ret); 987 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); 988 rds_ib_sub_signaled(ic, nr_sig); 989 goto out; 990 } 991 992 if (unlikely(failed_wr != &first->s_rdma_wr.wr)) { 993 printk(KERN_WARNING "RDS/IB: ib_post_send() rc=%d, but failed_wqe updated!\n", ret); 994 BUG_ON(failed_wr != &first->s_rdma_wr.wr); 995 } 996 997 998 out: 999 return ret; 1000 } 1001 1002 void rds_ib_xmit_path_complete(struct rds_conn_path *cp) 1003 { 1004 struct rds_connection *conn = cp->cp_conn; 1005 struct rds_ib_connection *ic = conn->c_transport_data; 1006 1007 /* We may have a pending ACK or window update we were unable 1008 * to send previously (due to flow control). Try again. */ 1009 rds_ib_attempt_ack(ic); 1010 } 1011