Andy Grover | 6a0979d | 2009-02-24 15:30:33 +0000 | [diff] [blame] | 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 | |
| 38 | #include "rds.h" |
| 39 | #include "rdma.h" |
| 40 | #include "ib.h" |
| 41 | |
| 42 | static void rds_ib_send_rdma_complete(struct rds_message *rm, |
| 43 | int wc_status) |
| 44 | { |
| 45 | int notify_status; |
| 46 | |
| 47 | switch (wc_status) { |
| 48 | case IB_WC_WR_FLUSH_ERR: |
| 49 | return; |
| 50 | |
| 51 | case IB_WC_SUCCESS: |
| 52 | notify_status = RDS_RDMA_SUCCESS; |
| 53 | break; |
| 54 | |
| 55 | case IB_WC_REM_ACCESS_ERR: |
| 56 | notify_status = RDS_RDMA_REMOTE_ERROR; |
| 57 | break; |
| 58 | |
| 59 | default: |
| 60 | notify_status = RDS_RDMA_OTHER_ERROR; |
| 61 | break; |
| 62 | } |
| 63 | rds_rdma_send_complete(rm, notify_status); |
| 64 | } |
| 65 | |
| 66 | static void rds_ib_send_unmap_rdma(struct rds_ib_connection *ic, |
| 67 | struct rds_rdma_op *op) |
| 68 | { |
| 69 | if (op->r_mapped) { |
| 70 | ib_dma_unmap_sg(ic->i_cm_id->device, |
| 71 | op->r_sg, op->r_nents, |
| 72 | op->r_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE); |
| 73 | op->r_mapped = 0; |
| 74 | } |
| 75 | } |
| 76 | |
| 77 | static void rds_ib_send_unmap_rm(struct rds_ib_connection *ic, |
| 78 | struct rds_ib_send_work *send, |
| 79 | int wc_status) |
| 80 | { |
| 81 | struct rds_message *rm = send->s_rm; |
| 82 | |
| 83 | rdsdebug("ic %p send %p rm %p\n", ic, send, rm); |
| 84 | |
| 85 | ib_dma_unmap_sg(ic->i_cm_id->device, |
| 86 | rm->m_sg, rm->m_nents, |
| 87 | DMA_TO_DEVICE); |
| 88 | |
| 89 | if (rm->m_rdma_op != NULL) { |
| 90 | rds_ib_send_unmap_rdma(ic, rm->m_rdma_op); |
| 91 | |
| 92 | /* If the user asked for a completion notification on this |
| 93 | * message, we can implement three different semantics: |
| 94 | * 1. Notify when we received the ACK on the RDS message |
| 95 | * that was queued with the RDMA. This provides reliable |
| 96 | * notification of RDMA status at the expense of a one-way |
| 97 | * packet delay. |
| 98 | * 2. Notify when the IB stack gives us the completion event for |
| 99 | * the RDMA operation. |
| 100 | * 3. Notify when the IB stack gives us the completion event for |
| 101 | * the accompanying RDS messages. |
| 102 | * Here, we implement approach #3. To implement approach #2, |
| 103 | * call rds_rdma_send_complete from the cq_handler. To implement #1, |
| 104 | * don't call rds_rdma_send_complete at all, and fall back to the notify |
| 105 | * handling in the ACK processing code. |
| 106 | * |
| 107 | * Note: There's no need to explicitly sync any RDMA buffers using |
| 108 | * ib_dma_sync_sg_for_cpu - the completion for the RDMA |
| 109 | * operation itself unmapped the RDMA buffers, which takes care |
| 110 | * of synching. |
| 111 | */ |
| 112 | rds_ib_send_rdma_complete(rm, wc_status); |
| 113 | |
| 114 | if (rm->m_rdma_op->r_write) |
| 115 | rds_stats_add(s_send_rdma_bytes, rm->m_rdma_op->r_bytes); |
| 116 | else |
| 117 | rds_stats_add(s_recv_rdma_bytes, rm->m_rdma_op->r_bytes); |
| 118 | } |
| 119 | |
| 120 | /* If anyone waited for this message to get flushed out, wake |
| 121 | * them up now */ |
| 122 | rds_message_unmapped(rm); |
| 123 | |
| 124 | rds_message_put(rm); |
| 125 | send->s_rm = NULL; |
| 126 | } |
| 127 | |
| 128 | void rds_ib_send_init_ring(struct rds_ib_connection *ic) |
| 129 | { |
| 130 | struct rds_ib_send_work *send; |
| 131 | u32 i; |
| 132 | |
| 133 | for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) { |
| 134 | struct ib_sge *sge; |
| 135 | |
| 136 | send->s_rm = NULL; |
| 137 | send->s_op = NULL; |
| 138 | |
| 139 | send->s_wr.wr_id = i; |
| 140 | send->s_wr.sg_list = send->s_sge; |
| 141 | send->s_wr.num_sge = 1; |
| 142 | send->s_wr.opcode = IB_WR_SEND; |
| 143 | send->s_wr.send_flags = 0; |
| 144 | send->s_wr.ex.imm_data = 0; |
| 145 | |
| 146 | sge = rds_ib_data_sge(ic, send->s_sge); |
| 147 | sge->lkey = ic->i_mr->lkey; |
| 148 | |
| 149 | sge = rds_ib_header_sge(ic, send->s_sge); |
| 150 | sge->addr = ic->i_send_hdrs_dma + (i * sizeof(struct rds_header)); |
| 151 | sge->length = sizeof(struct rds_header); |
| 152 | sge->lkey = ic->i_mr->lkey; |
| 153 | } |
| 154 | } |
| 155 | |
| 156 | void rds_ib_send_clear_ring(struct rds_ib_connection *ic) |
| 157 | { |
| 158 | struct rds_ib_send_work *send; |
| 159 | u32 i; |
| 160 | |
| 161 | for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) { |
| 162 | if (send->s_wr.opcode == 0xdead) |
| 163 | continue; |
| 164 | if (send->s_rm) |
| 165 | rds_ib_send_unmap_rm(ic, send, IB_WC_WR_FLUSH_ERR); |
| 166 | if (send->s_op) |
| 167 | rds_ib_send_unmap_rdma(ic, send->s_op); |
| 168 | } |
| 169 | } |
| 170 | |
| 171 | /* |
| 172 | * The _oldest/_free ring operations here race cleanly with the alloc/unalloc |
| 173 | * operations performed in the send path. As the sender allocs and potentially |
| 174 | * unallocs the next free entry in the ring it doesn't alter which is |
| 175 | * the next to be freed, which is what this is concerned with. |
| 176 | */ |
| 177 | void rds_ib_send_cq_comp_handler(struct ib_cq *cq, void *context) |
| 178 | { |
| 179 | struct rds_connection *conn = context; |
| 180 | struct rds_ib_connection *ic = conn->c_transport_data; |
| 181 | struct ib_wc wc; |
| 182 | struct rds_ib_send_work *send; |
| 183 | u32 completed; |
| 184 | u32 oldest; |
| 185 | u32 i = 0; |
| 186 | int ret; |
| 187 | |
| 188 | rdsdebug("cq %p conn %p\n", cq, conn); |
| 189 | rds_ib_stats_inc(s_ib_tx_cq_call); |
| 190 | ret = ib_req_notify_cq(cq, IB_CQ_NEXT_COMP); |
| 191 | if (ret) |
| 192 | rdsdebug("ib_req_notify_cq send failed: %d\n", ret); |
| 193 | |
| 194 | while (ib_poll_cq(cq, 1, &wc) > 0) { |
| 195 | rdsdebug("wc wr_id 0x%llx status %u byte_len %u imm_data %u\n", |
| 196 | (unsigned long long)wc.wr_id, wc.status, wc.byte_len, |
| 197 | be32_to_cpu(wc.ex.imm_data)); |
| 198 | rds_ib_stats_inc(s_ib_tx_cq_event); |
| 199 | |
| 200 | if (wc.wr_id == RDS_IB_ACK_WR_ID) { |
| 201 | if (ic->i_ack_queued + HZ/2 < jiffies) |
| 202 | rds_ib_stats_inc(s_ib_tx_stalled); |
| 203 | rds_ib_ack_send_complete(ic); |
| 204 | continue; |
| 205 | } |
| 206 | |
| 207 | oldest = rds_ib_ring_oldest(&ic->i_send_ring); |
| 208 | |
| 209 | completed = rds_ib_ring_completed(&ic->i_send_ring, wc.wr_id, oldest); |
| 210 | |
| 211 | for (i = 0; i < completed; i++) { |
| 212 | send = &ic->i_sends[oldest]; |
| 213 | |
| 214 | /* In the error case, wc.opcode sometimes contains garbage */ |
| 215 | switch (send->s_wr.opcode) { |
| 216 | case IB_WR_SEND: |
| 217 | if (send->s_rm) |
| 218 | rds_ib_send_unmap_rm(ic, send, wc.status); |
| 219 | break; |
| 220 | case IB_WR_RDMA_WRITE: |
| 221 | case IB_WR_RDMA_READ: |
| 222 | /* Nothing to be done - the SG list will be unmapped |
| 223 | * when the SEND completes. */ |
| 224 | break; |
| 225 | default: |
| 226 | if (printk_ratelimit()) |
| 227 | printk(KERN_NOTICE |
| 228 | "RDS/IB: %s: unexpected opcode 0x%x in WR!\n", |
| 229 | __func__, send->s_wr.opcode); |
| 230 | break; |
| 231 | } |
| 232 | |
| 233 | send->s_wr.opcode = 0xdead; |
| 234 | send->s_wr.num_sge = 1; |
| 235 | if (send->s_queued + HZ/2 < jiffies) |
| 236 | rds_ib_stats_inc(s_ib_tx_stalled); |
| 237 | |
| 238 | /* If a RDMA operation produced an error, signal this right |
| 239 | * away. If we don't, the subsequent SEND that goes with this |
| 240 | * RDMA will be canceled with ERR_WFLUSH, and the application |
| 241 | * never learn that the RDMA failed. */ |
| 242 | if (unlikely(wc.status == IB_WC_REM_ACCESS_ERR && send->s_op)) { |
| 243 | struct rds_message *rm; |
| 244 | |
| 245 | rm = rds_send_get_message(conn, send->s_op); |
| 246 | if (rm) |
| 247 | rds_ib_send_rdma_complete(rm, wc.status); |
| 248 | } |
| 249 | |
| 250 | oldest = (oldest + 1) % ic->i_send_ring.w_nr; |
| 251 | } |
| 252 | |
| 253 | rds_ib_ring_free(&ic->i_send_ring, completed); |
| 254 | |
| 255 | if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags) |
| 256 | || test_bit(0, &conn->c_map_queued)) |
| 257 | queue_delayed_work(rds_wq, &conn->c_send_w, 0); |
| 258 | |
| 259 | /* We expect errors as the qp is drained during shutdown */ |
| 260 | if (wc.status != IB_WC_SUCCESS && rds_conn_up(conn)) { |
| 261 | rds_ib_conn_error(conn, |
| 262 | "send completion on %pI4 " |
| 263 | "had status %u, disconnecting and reconnecting\n", |
| 264 | &conn->c_faddr, wc.status); |
| 265 | } |
| 266 | } |
| 267 | } |
| 268 | |
| 269 | /* |
| 270 | * This is the main function for allocating credits when sending |
| 271 | * messages. |
| 272 | * |
| 273 | * Conceptually, we have two counters: |
| 274 | * - send credits: this tells us how many WRs we're allowed |
| 275 | * to submit without overruning the reciever's queue. For |
| 276 | * each SEND WR we post, we decrement this by one. |
| 277 | * |
| 278 | * - posted credits: this tells us how many WRs we recently |
| 279 | * posted to the receive queue. This value is transferred |
| 280 | * to the peer as a "credit update" in a RDS header field. |
| 281 | * Every time we transmit credits to the peer, we subtract |
| 282 | * the amount of transferred credits from this counter. |
| 283 | * |
| 284 | * It is essential that we avoid situations where both sides have |
| 285 | * exhausted their send credits, and are unable to send new credits |
| 286 | * to the peer. We achieve this by requiring that we send at least |
| 287 | * one credit update to the peer before exhausting our credits. |
| 288 | * When new credits arrive, we subtract one credit that is withheld |
| 289 | * until we've posted new buffers and are ready to transmit these |
| 290 | * credits (see rds_ib_send_add_credits below). |
| 291 | * |
| 292 | * The RDS send code is essentially single-threaded; rds_send_xmit |
| 293 | * grabs c_send_lock to ensure exclusive access to the send ring. |
| 294 | * However, the ACK sending code is independent and can race with |
| 295 | * message SENDs. |
| 296 | * |
| 297 | * In the send path, we need to update the counters for send credits |
| 298 | * and the counter of posted buffers atomically - when we use the |
| 299 | * last available credit, we cannot allow another thread to race us |
| 300 | * and grab the posted credits counter. Hence, we have to use a |
| 301 | * spinlock to protect the credit counter, or use atomics. |
| 302 | * |
| 303 | * Spinlocks shared between the send and the receive path are bad, |
| 304 | * because they create unnecessary delays. An early implementation |
| 305 | * using a spinlock showed a 5% degradation in throughput at some |
| 306 | * loads. |
| 307 | * |
| 308 | * This implementation avoids spinlocks completely, putting both |
| 309 | * counters into a single atomic, and updating that atomic using |
| 310 | * atomic_add (in the receive path, when receiving fresh credits), |
| 311 | * and using atomic_cmpxchg when updating the two counters. |
| 312 | */ |
| 313 | int rds_ib_send_grab_credits(struct rds_ib_connection *ic, |
Steve Wise | 7b70d03 | 2009-04-09 14:09:39 +0000 | [diff] [blame^] | 314 | u32 wanted, u32 *adv_credits, int need_posted, int max_posted) |
Andy Grover | 6a0979d | 2009-02-24 15:30:33 +0000 | [diff] [blame] | 315 | { |
| 316 | unsigned int avail, posted, got = 0, advertise; |
| 317 | long oldval, newval; |
| 318 | |
| 319 | *adv_credits = 0; |
| 320 | if (!ic->i_flowctl) |
| 321 | return wanted; |
| 322 | |
| 323 | try_again: |
| 324 | advertise = 0; |
| 325 | oldval = newval = atomic_read(&ic->i_credits); |
| 326 | posted = IB_GET_POST_CREDITS(oldval); |
| 327 | avail = IB_GET_SEND_CREDITS(oldval); |
| 328 | |
| 329 | rdsdebug("rds_ib_send_grab_credits(%u): credits=%u posted=%u\n", |
| 330 | wanted, avail, posted); |
| 331 | |
| 332 | /* The last credit must be used to send a credit update. */ |
| 333 | if (avail && !posted) |
| 334 | avail--; |
| 335 | |
| 336 | if (avail < wanted) { |
| 337 | struct rds_connection *conn = ic->i_cm_id->context; |
| 338 | |
| 339 | /* Oops, there aren't that many credits left! */ |
| 340 | set_bit(RDS_LL_SEND_FULL, &conn->c_flags); |
| 341 | got = avail; |
| 342 | } else { |
| 343 | /* Sometimes you get what you want, lalala. */ |
| 344 | got = wanted; |
| 345 | } |
| 346 | newval -= IB_SET_SEND_CREDITS(got); |
| 347 | |
| 348 | /* |
| 349 | * If need_posted is non-zero, then the caller wants |
| 350 | * the posted regardless of whether any send credits are |
| 351 | * available. |
| 352 | */ |
| 353 | if (posted && (got || need_posted)) { |
Steve Wise | 7b70d03 | 2009-04-09 14:09:39 +0000 | [diff] [blame^] | 354 | advertise = min_t(unsigned int, posted, max_posted); |
Andy Grover | 6a0979d | 2009-02-24 15:30:33 +0000 | [diff] [blame] | 355 | newval -= IB_SET_POST_CREDITS(advertise); |
| 356 | } |
| 357 | |
| 358 | /* Finally bill everything */ |
| 359 | if (atomic_cmpxchg(&ic->i_credits, oldval, newval) != oldval) |
| 360 | goto try_again; |
| 361 | |
| 362 | *adv_credits = advertise; |
| 363 | return got; |
| 364 | } |
| 365 | |
| 366 | void rds_ib_send_add_credits(struct rds_connection *conn, unsigned int credits) |
| 367 | { |
| 368 | struct rds_ib_connection *ic = conn->c_transport_data; |
| 369 | |
| 370 | if (credits == 0) |
| 371 | return; |
| 372 | |
| 373 | rdsdebug("rds_ib_send_add_credits(%u): current=%u%s\n", |
| 374 | credits, |
| 375 | IB_GET_SEND_CREDITS(atomic_read(&ic->i_credits)), |
| 376 | test_bit(RDS_LL_SEND_FULL, &conn->c_flags) ? ", ll_send_full" : ""); |
| 377 | |
| 378 | atomic_add(IB_SET_SEND_CREDITS(credits), &ic->i_credits); |
| 379 | if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags)) |
| 380 | queue_delayed_work(rds_wq, &conn->c_send_w, 0); |
| 381 | |
| 382 | WARN_ON(IB_GET_SEND_CREDITS(credits) >= 16384); |
| 383 | |
| 384 | rds_ib_stats_inc(s_ib_rx_credit_updates); |
| 385 | } |
| 386 | |
| 387 | void rds_ib_advertise_credits(struct rds_connection *conn, unsigned int posted) |
| 388 | { |
| 389 | struct rds_ib_connection *ic = conn->c_transport_data; |
| 390 | |
| 391 | if (posted == 0) |
| 392 | return; |
| 393 | |
| 394 | atomic_add(IB_SET_POST_CREDITS(posted), &ic->i_credits); |
| 395 | |
| 396 | /* Decide whether to send an update to the peer now. |
| 397 | * If we would send a credit update for every single buffer we |
| 398 | * post, we would end up with an ACK storm (ACK arrives, |
| 399 | * consumes buffer, we refill the ring, send ACK to remote |
| 400 | * advertising the newly posted buffer... ad inf) |
| 401 | * |
| 402 | * Performance pretty much depends on how often we send |
| 403 | * credit updates - too frequent updates mean lots of ACKs. |
| 404 | * Too infrequent updates, and the peer will run out of |
| 405 | * credits and has to throttle. |
| 406 | * For the time being, 16 seems to be a good compromise. |
| 407 | */ |
| 408 | if (IB_GET_POST_CREDITS(atomic_read(&ic->i_credits)) >= 16) |
| 409 | set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); |
| 410 | } |
| 411 | |
| 412 | static inline void |
| 413 | rds_ib_xmit_populate_wr(struct rds_ib_connection *ic, |
| 414 | struct rds_ib_send_work *send, unsigned int pos, |
| 415 | unsigned long buffer, unsigned int length, |
| 416 | int send_flags) |
| 417 | { |
| 418 | struct ib_sge *sge; |
| 419 | |
| 420 | WARN_ON(pos != send - ic->i_sends); |
| 421 | |
| 422 | send->s_wr.send_flags = send_flags; |
| 423 | send->s_wr.opcode = IB_WR_SEND; |
| 424 | send->s_wr.num_sge = 2; |
| 425 | send->s_wr.next = NULL; |
| 426 | send->s_queued = jiffies; |
| 427 | send->s_op = NULL; |
| 428 | |
| 429 | if (length != 0) { |
| 430 | sge = rds_ib_data_sge(ic, send->s_sge); |
| 431 | sge->addr = buffer; |
| 432 | sge->length = length; |
| 433 | sge->lkey = ic->i_mr->lkey; |
| 434 | |
| 435 | sge = rds_ib_header_sge(ic, send->s_sge); |
| 436 | } else { |
| 437 | /* We're sending a packet with no payload. There is only |
| 438 | * one SGE */ |
| 439 | send->s_wr.num_sge = 1; |
| 440 | sge = &send->s_sge[0]; |
| 441 | } |
| 442 | |
| 443 | sge->addr = ic->i_send_hdrs_dma + (pos * sizeof(struct rds_header)); |
| 444 | sge->length = sizeof(struct rds_header); |
| 445 | sge->lkey = ic->i_mr->lkey; |
| 446 | } |
| 447 | |
| 448 | /* |
| 449 | * This can be called multiple times for a given message. The first time |
| 450 | * we see a message we map its scatterlist into the IB device so that |
| 451 | * we can provide that mapped address to the IB scatter gather entries |
| 452 | * in the IB work requests. We translate the scatterlist into a series |
| 453 | * of work requests that fragment the message. These work requests complete |
| 454 | * in order so we pass ownership of the message to the completion handler |
| 455 | * once we send the final fragment. |
| 456 | * |
| 457 | * The RDS core uses the c_send_lock to only enter this function once |
| 458 | * per connection. This makes sure that the tx ring alloc/unalloc pairs |
| 459 | * don't get out of sync and confuse the ring. |
| 460 | */ |
| 461 | int rds_ib_xmit(struct rds_connection *conn, struct rds_message *rm, |
| 462 | unsigned int hdr_off, unsigned int sg, unsigned int off) |
| 463 | { |
| 464 | struct rds_ib_connection *ic = conn->c_transport_data; |
| 465 | struct ib_device *dev = ic->i_cm_id->device; |
| 466 | struct rds_ib_send_work *send = NULL; |
| 467 | struct rds_ib_send_work *first; |
| 468 | struct rds_ib_send_work *prev; |
| 469 | struct ib_send_wr *failed_wr; |
| 470 | struct scatterlist *scat; |
| 471 | u32 pos; |
| 472 | u32 i; |
| 473 | u32 work_alloc; |
| 474 | u32 credit_alloc; |
| 475 | u32 posted; |
| 476 | u32 adv_credits = 0; |
| 477 | int send_flags = 0; |
| 478 | int sent; |
| 479 | int ret; |
| 480 | int flow_controlled = 0; |
| 481 | |
| 482 | BUG_ON(off % RDS_FRAG_SIZE); |
| 483 | BUG_ON(hdr_off != 0 && hdr_off != sizeof(struct rds_header)); |
| 484 | |
| 485 | /* FIXME we may overallocate here */ |
| 486 | if (be32_to_cpu(rm->m_inc.i_hdr.h_len) == 0) |
| 487 | i = 1; |
| 488 | else |
| 489 | i = ceil(be32_to_cpu(rm->m_inc.i_hdr.h_len), RDS_FRAG_SIZE); |
| 490 | |
| 491 | work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos); |
| 492 | if (work_alloc == 0) { |
| 493 | set_bit(RDS_LL_SEND_FULL, &conn->c_flags); |
| 494 | rds_ib_stats_inc(s_ib_tx_ring_full); |
| 495 | ret = -ENOMEM; |
| 496 | goto out; |
| 497 | } |
| 498 | |
| 499 | credit_alloc = work_alloc; |
| 500 | if (ic->i_flowctl) { |
Steve Wise | 7b70d03 | 2009-04-09 14:09:39 +0000 | [diff] [blame^] | 501 | credit_alloc = rds_ib_send_grab_credits(ic, work_alloc, &posted, 0, RDS_MAX_ADV_CREDIT); |
Andy Grover | 6a0979d | 2009-02-24 15:30:33 +0000 | [diff] [blame] | 502 | adv_credits += posted; |
| 503 | if (credit_alloc < work_alloc) { |
| 504 | rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - credit_alloc); |
| 505 | work_alloc = credit_alloc; |
| 506 | flow_controlled++; |
| 507 | } |
| 508 | if (work_alloc == 0) { |
Steve Wise | d39e060 | 2009-04-09 14:09:38 +0000 | [diff] [blame] | 509 | set_bit(RDS_LL_SEND_FULL, &conn->c_flags); |
Andy Grover | 6a0979d | 2009-02-24 15:30:33 +0000 | [diff] [blame] | 510 | rds_ib_stats_inc(s_ib_tx_throttle); |
| 511 | ret = -ENOMEM; |
| 512 | goto out; |
| 513 | } |
| 514 | } |
| 515 | |
| 516 | /* map the message the first time we see it */ |
| 517 | if (ic->i_rm == NULL) { |
| 518 | /* |
| 519 | printk(KERN_NOTICE "rds_ib_xmit prep msg dport=%u flags=0x%x len=%d\n", |
| 520 | be16_to_cpu(rm->m_inc.i_hdr.h_dport), |
| 521 | rm->m_inc.i_hdr.h_flags, |
| 522 | be32_to_cpu(rm->m_inc.i_hdr.h_len)); |
| 523 | */ |
| 524 | if (rm->m_nents) { |
| 525 | rm->m_count = ib_dma_map_sg(dev, |
| 526 | rm->m_sg, rm->m_nents, DMA_TO_DEVICE); |
| 527 | rdsdebug("ic %p mapping rm %p: %d\n", ic, rm, rm->m_count); |
| 528 | if (rm->m_count == 0) { |
| 529 | rds_ib_stats_inc(s_ib_tx_sg_mapping_failure); |
| 530 | rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); |
| 531 | ret = -ENOMEM; /* XXX ? */ |
| 532 | goto out; |
| 533 | } |
| 534 | } else { |
| 535 | rm->m_count = 0; |
| 536 | } |
| 537 | |
| 538 | ic->i_unsignaled_wrs = rds_ib_sysctl_max_unsig_wrs; |
| 539 | ic->i_unsignaled_bytes = rds_ib_sysctl_max_unsig_bytes; |
| 540 | rds_message_addref(rm); |
| 541 | ic->i_rm = rm; |
| 542 | |
| 543 | /* Finalize the header */ |
| 544 | if (test_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags)) |
| 545 | rm->m_inc.i_hdr.h_flags |= RDS_FLAG_ACK_REQUIRED; |
| 546 | if (test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) |
| 547 | rm->m_inc.i_hdr.h_flags |= RDS_FLAG_RETRANSMITTED; |
| 548 | |
| 549 | /* If it has a RDMA op, tell the peer we did it. This is |
| 550 | * used by the peer to release use-once RDMA MRs. */ |
| 551 | if (rm->m_rdma_op) { |
| 552 | struct rds_ext_header_rdma ext_hdr; |
| 553 | |
| 554 | ext_hdr.h_rdma_rkey = cpu_to_be32(rm->m_rdma_op->r_key); |
| 555 | rds_message_add_extension(&rm->m_inc.i_hdr, |
| 556 | RDS_EXTHDR_RDMA, &ext_hdr, sizeof(ext_hdr)); |
| 557 | } |
| 558 | if (rm->m_rdma_cookie) { |
| 559 | rds_message_add_rdma_dest_extension(&rm->m_inc.i_hdr, |
| 560 | rds_rdma_cookie_key(rm->m_rdma_cookie), |
| 561 | rds_rdma_cookie_offset(rm->m_rdma_cookie)); |
| 562 | } |
| 563 | |
| 564 | /* Note - rds_ib_piggyb_ack clears the ACK_REQUIRED bit, so |
| 565 | * we should not do this unless we have a chance of at least |
| 566 | * sticking the header into the send ring. Which is why we |
| 567 | * should call rds_ib_ring_alloc first. */ |
| 568 | rm->m_inc.i_hdr.h_ack = cpu_to_be64(rds_ib_piggyb_ack(ic)); |
| 569 | rds_message_make_checksum(&rm->m_inc.i_hdr); |
| 570 | |
| 571 | /* |
| 572 | * Update adv_credits since we reset the ACK_REQUIRED bit. |
| 573 | */ |
Steve Wise | 7b70d03 | 2009-04-09 14:09:39 +0000 | [diff] [blame^] | 574 | rds_ib_send_grab_credits(ic, 0, &posted, 1, RDS_MAX_ADV_CREDIT - adv_credits); |
Andy Grover | 6a0979d | 2009-02-24 15:30:33 +0000 | [diff] [blame] | 575 | adv_credits += posted; |
| 576 | BUG_ON(adv_credits > 255); |
| 577 | } else if (ic->i_rm != rm) |
| 578 | BUG(); |
| 579 | |
| 580 | send = &ic->i_sends[pos]; |
| 581 | first = send; |
| 582 | prev = NULL; |
| 583 | scat = &rm->m_sg[sg]; |
| 584 | sent = 0; |
| 585 | i = 0; |
| 586 | |
| 587 | /* Sometimes you want to put a fence between an RDMA |
| 588 | * READ and the following SEND. |
| 589 | * We could either do this all the time |
| 590 | * or when requested by the user. Right now, we let |
| 591 | * the application choose. |
| 592 | */ |
| 593 | if (rm->m_rdma_op && rm->m_rdma_op->r_fence) |
| 594 | send_flags = IB_SEND_FENCE; |
| 595 | |
| 596 | /* |
| 597 | * We could be copying the header into the unused tail of the page. |
| 598 | * That would need to be changed in the future when those pages might |
| 599 | * be mapped userspace pages or page cache pages. So instead we always |
| 600 | * use a second sge and our long-lived ring of mapped headers. We send |
| 601 | * the header after the data so that the data payload can be aligned on |
| 602 | * the receiver. |
| 603 | */ |
| 604 | |
| 605 | /* handle a 0-len message */ |
| 606 | if (be32_to_cpu(rm->m_inc.i_hdr.h_len) == 0) { |
| 607 | rds_ib_xmit_populate_wr(ic, send, pos, 0, 0, send_flags); |
| 608 | goto add_header; |
| 609 | } |
| 610 | |
| 611 | /* if there's data reference it with a chain of work reqs */ |
| 612 | for (; i < work_alloc && scat != &rm->m_sg[rm->m_count]; i++) { |
| 613 | unsigned int len; |
| 614 | |
| 615 | send = &ic->i_sends[pos]; |
| 616 | |
| 617 | len = min(RDS_FRAG_SIZE, ib_sg_dma_len(dev, scat) - off); |
| 618 | rds_ib_xmit_populate_wr(ic, send, pos, |
| 619 | ib_sg_dma_address(dev, scat) + off, len, |
| 620 | send_flags); |
| 621 | |
| 622 | /* |
| 623 | * We want to delay signaling completions just enough to get |
| 624 | * the batching benefits but not so much that we create dead time |
| 625 | * on the wire. |
| 626 | */ |
| 627 | if (ic->i_unsignaled_wrs-- == 0) { |
| 628 | ic->i_unsignaled_wrs = rds_ib_sysctl_max_unsig_wrs; |
| 629 | send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED; |
| 630 | } |
| 631 | |
| 632 | ic->i_unsignaled_bytes -= len; |
| 633 | if (ic->i_unsignaled_bytes <= 0) { |
| 634 | ic->i_unsignaled_bytes = rds_ib_sysctl_max_unsig_bytes; |
| 635 | send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED; |
| 636 | } |
| 637 | |
| 638 | /* |
| 639 | * Always signal the last one if we're stopping due to flow control. |
| 640 | */ |
| 641 | if (flow_controlled && i == (work_alloc-1)) |
| 642 | send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED; |
| 643 | |
| 644 | rdsdebug("send %p wr %p num_sge %u next %p\n", send, |
| 645 | &send->s_wr, send->s_wr.num_sge, send->s_wr.next); |
| 646 | |
| 647 | sent += len; |
| 648 | off += len; |
| 649 | if (off == ib_sg_dma_len(dev, scat)) { |
| 650 | scat++; |
| 651 | off = 0; |
| 652 | } |
| 653 | |
| 654 | add_header: |
| 655 | /* Tack on the header after the data. The header SGE should already |
| 656 | * have been set up to point to the right header buffer. */ |
| 657 | memcpy(&ic->i_send_hdrs[pos], &rm->m_inc.i_hdr, sizeof(struct rds_header)); |
| 658 | |
| 659 | if (0) { |
| 660 | struct rds_header *hdr = &ic->i_send_hdrs[pos]; |
| 661 | |
| 662 | printk(KERN_NOTICE "send WR dport=%u flags=0x%x len=%d\n", |
| 663 | be16_to_cpu(hdr->h_dport), |
| 664 | hdr->h_flags, |
| 665 | be32_to_cpu(hdr->h_len)); |
| 666 | } |
| 667 | if (adv_credits) { |
| 668 | struct rds_header *hdr = &ic->i_send_hdrs[pos]; |
| 669 | |
| 670 | /* add credit and redo the header checksum */ |
| 671 | hdr->h_credit = adv_credits; |
| 672 | rds_message_make_checksum(hdr); |
| 673 | adv_credits = 0; |
| 674 | rds_ib_stats_inc(s_ib_tx_credit_updates); |
| 675 | } |
| 676 | |
| 677 | if (prev) |
| 678 | prev->s_wr.next = &send->s_wr; |
| 679 | prev = send; |
| 680 | |
| 681 | pos = (pos + 1) % ic->i_send_ring.w_nr; |
| 682 | } |
| 683 | |
| 684 | /* Account the RDS header in the number of bytes we sent, but just once. |
| 685 | * The caller has no concept of fragmentation. */ |
| 686 | if (hdr_off == 0) |
| 687 | sent += sizeof(struct rds_header); |
| 688 | |
| 689 | /* if we finished the message then send completion owns it */ |
| 690 | if (scat == &rm->m_sg[rm->m_count]) { |
| 691 | prev->s_rm = ic->i_rm; |
| 692 | prev->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED; |
| 693 | ic->i_rm = NULL; |
| 694 | } |
| 695 | |
| 696 | if (i < work_alloc) { |
| 697 | rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i); |
| 698 | work_alloc = i; |
| 699 | } |
| 700 | if (ic->i_flowctl && i < credit_alloc) |
| 701 | rds_ib_send_add_credits(conn, credit_alloc - i); |
| 702 | |
| 703 | /* XXX need to worry about failed_wr and partial sends. */ |
| 704 | failed_wr = &first->s_wr; |
| 705 | ret = ib_post_send(ic->i_cm_id->qp, &first->s_wr, &failed_wr); |
| 706 | rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic, |
| 707 | first, &first->s_wr, ret, failed_wr); |
| 708 | BUG_ON(failed_wr != &first->s_wr); |
| 709 | if (ret) { |
| 710 | printk(KERN_WARNING "RDS/IB: ib_post_send to %pI4 " |
| 711 | "returned %d\n", &conn->c_faddr, ret); |
| 712 | rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); |
| 713 | if (prev->s_rm) { |
| 714 | ic->i_rm = prev->s_rm; |
| 715 | prev->s_rm = NULL; |
| 716 | } |
| 717 | /* Finesse this later */ |
| 718 | BUG(); |
| 719 | goto out; |
| 720 | } |
| 721 | |
| 722 | ret = sent; |
| 723 | out: |
| 724 | BUG_ON(adv_credits); |
| 725 | return ret; |
| 726 | } |
| 727 | |
| 728 | int rds_ib_xmit_rdma(struct rds_connection *conn, struct rds_rdma_op *op) |
| 729 | { |
| 730 | struct rds_ib_connection *ic = conn->c_transport_data; |
| 731 | struct rds_ib_send_work *send = NULL; |
| 732 | struct rds_ib_send_work *first; |
| 733 | struct rds_ib_send_work *prev; |
| 734 | struct ib_send_wr *failed_wr; |
| 735 | struct rds_ib_device *rds_ibdev; |
| 736 | struct scatterlist *scat; |
| 737 | unsigned long len; |
| 738 | u64 remote_addr = op->r_remote_addr; |
| 739 | u32 pos; |
| 740 | u32 work_alloc; |
| 741 | u32 i; |
| 742 | u32 j; |
| 743 | int sent; |
| 744 | int ret; |
| 745 | int num_sge; |
| 746 | |
| 747 | rds_ibdev = ib_get_client_data(ic->i_cm_id->device, &rds_ib_client); |
| 748 | |
| 749 | /* map the message the first time we see it */ |
| 750 | if (!op->r_mapped) { |
| 751 | op->r_count = ib_dma_map_sg(ic->i_cm_id->device, |
| 752 | op->r_sg, op->r_nents, (op->r_write) ? |
| 753 | DMA_TO_DEVICE : DMA_FROM_DEVICE); |
| 754 | rdsdebug("ic %p mapping op %p: %d\n", ic, op, op->r_count); |
| 755 | if (op->r_count == 0) { |
| 756 | rds_ib_stats_inc(s_ib_tx_sg_mapping_failure); |
| 757 | ret = -ENOMEM; /* XXX ? */ |
| 758 | goto out; |
| 759 | } |
| 760 | |
| 761 | op->r_mapped = 1; |
| 762 | } |
| 763 | |
| 764 | /* |
| 765 | * Instead of knowing how to return a partial rdma read/write we insist that there |
| 766 | * be enough work requests to send the entire message. |
| 767 | */ |
| 768 | i = ceil(op->r_count, rds_ibdev->max_sge); |
| 769 | |
| 770 | work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos); |
| 771 | if (work_alloc != i) { |
| 772 | rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); |
| 773 | rds_ib_stats_inc(s_ib_tx_ring_full); |
| 774 | ret = -ENOMEM; |
| 775 | goto out; |
| 776 | } |
| 777 | |
| 778 | send = &ic->i_sends[pos]; |
| 779 | first = send; |
| 780 | prev = NULL; |
| 781 | scat = &op->r_sg[0]; |
| 782 | sent = 0; |
| 783 | num_sge = op->r_count; |
| 784 | |
| 785 | for (i = 0; i < work_alloc && scat != &op->r_sg[op->r_count]; i++) { |
| 786 | send->s_wr.send_flags = 0; |
| 787 | send->s_queued = jiffies; |
| 788 | /* |
| 789 | * We want to delay signaling completions just enough to get |
| 790 | * the batching benefits but not so much that we create dead time on the wire. |
| 791 | */ |
| 792 | if (ic->i_unsignaled_wrs-- == 0) { |
| 793 | ic->i_unsignaled_wrs = rds_ib_sysctl_max_unsig_wrs; |
| 794 | send->s_wr.send_flags = IB_SEND_SIGNALED; |
| 795 | } |
| 796 | |
| 797 | send->s_wr.opcode = op->r_write ? IB_WR_RDMA_WRITE : IB_WR_RDMA_READ; |
| 798 | send->s_wr.wr.rdma.remote_addr = remote_addr; |
| 799 | send->s_wr.wr.rdma.rkey = op->r_key; |
| 800 | send->s_op = op; |
| 801 | |
| 802 | if (num_sge > rds_ibdev->max_sge) { |
| 803 | send->s_wr.num_sge = rds_ibdev->max_sge; |
| 804 | num_sge -= rds_ibdev->max_sge; |
| 805 | } else { |
| 806 | send->s_wr.num_sge = num_sge; |
| 807 | } |
| 808 | |
| 809 | send->s_wr.next = NULL; |
| 810 | |
| 811 | if (prev) |
| 812 | prev->s_wr.next = &send->s_wr; |
| 813 | |
| 814 | for (j = 0; j < send->s_wr.num_sge && scat != &op->r_sg[op->r_count]; j++) { |
| 815 | len = ib_sg_dma_len(ic->i_cm_id->device, scat); |
| 816 | send->s_sge[j].addr = |
| 817 | ib_sg_dma_address(ic->i_cm_id->device, scat); |
| 818 | send->s_sge[j].length = len; |
| 819 | send->s_sge[j].lkey = ic->i_mr->lkey; |
| 820 | |
| 821 | sent += len; |
| 822 | rdsdebug("ic %p sent %d remote_addr %llu\n", ic, sent, remote_addr); |
| 823 | |
| 824 | remote_addr += len; |
| 825 | scat++; |
| 826 | } |
| 827 | |
| 828 | rdsdebug("send %p wr %p num_sge %u next %p\n", send, |
| 829 | &send->s_wr, send->s_wr.num_sge, send->s_wr.next); |
| 830 | |
| 831 | prev = send; |
| 832 | if (++send == &ic->i_sends[ic->i_send_ring.w_nr]) |
| 833 | send = ic->i_sends; |
| 834 | } |
| 835 | |
| 836 | /* if we finished the message then send completion owns it */ |
| 837 | if (scat == &op->r_sg[op->r_count]) |
| 838 | prev->s_wr.send_flags = IB_SEND_SIGNALED; |
| 839 | |
| 840 | if (i < work_alloc) { |
| 841 | rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i); |
| 842 | work_alloc = i; |
| 843 | } |
| 844 | |
| 845 | failed_wr = &first->s_wr; |
| 846 | ret = ib_post_send(ic->i_cm_id->qp, &first->s_wr, &failed_wr); |
| 847 | rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic, |
| 848 | first, &first->s_wr, ret, failed_wr); |
| 849 | BUG_ON(failed_wr != &first->s_wr); |
| 850 | if (ret) { |
| 851 | printk(KERN_WARNING "RDS/IB: rdma ib_post_send to %pI4 " |
| 852 | "returned %d\n", &conn->c_faddr, ret); |
| 853 | rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); |
| 854 | goto out; |
| 855 | } |
| 856 | |
| 857 | if (unlikely(failed_wr != &first->s_wr)) { |
| 858 | printk(KERN_WARNING "RDS/IB: ib_post_send() rc=%d, but failed_wqe updated!\n", ret); |
| 859 | BUG_ON(failed_wr != &first->s_wr); |
| 860 | } |
| 861 | |
| 862 | |
| 863 | out: |
| 864 | return ret; |
| 865 | } |
| 866 | |
| 867 | void rds_ib_xmit_complete(struct rds_connection *conn) |
| 868 | { |
| 869 | struct rds_ib_connection *ic = conn->c_transport_data; |
| 870 | |
| 871 | /* We may have a pending ACK or window update we were unable |
| 872 | * to send previously (due to flow control). Try again. */ |
| 873 | rds_ib_attempt_ack(ic); |
| 874 | } |