Andy Grover | fcd8b7c | 2009-02-24 15:30:36 +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 "iw.h" |
| 41 | |
| 42 | static void rds_iw_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_iw_send_unmap_rdma(struct rds_iw_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_iw_send_unmap_rm(struct rds_iw_connection *ic, |
| 78 | struct rds_iw_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_iw_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_iw_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_iw_send_init_ring(struct rds_iw_connection *ic) |
| 129 | { |
| 130 | struct rds_iw_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 | send->s_mapping = NULL; |
| 139 | |
| 140 | send->s_wr.next = NULL; |
| 141 | send->s_wr.wr_id = i; |
| 142 | send->s_wr.sg_list = send->s_sge; |
| 143 | send->s_wr.num_sge = 1; |
| 144 | send->s_wr.opcode = IB_WR_SEND; |
| 145 | send->s_wr.send_flags = 0; |
| 146 | send->s_wr.ex.imm_data = 0; |
| 147 | |
| 148 | sge = rds_iw_data_sge(ic, send->s_sge); |
| 149 | sge->lkey = 0; |
| 150 | |
| 151 | sge = rds_iw_header_sge(ic, send->s_sge); |
| 152 | sge->addr = ic->i_send_hdrs_dma + (i * sizeof(struct rds_header)); |
| 153 | sge->length = sizeof(struct rds_header); |
| 154 | sge->lkey = 0; |
| 155 | |
| 156 | send->s_mr = ib_alloc_fast_reg_mr(ic->i_pd, fastreg_message_size); |
| 157 | if (IS_ERR(send->s_mr)) { |
| 158 | printk(KERN_WARNING "RDS/IW: ib_alloc_fast_reg_mr failed\n"); |
| 159 | break; |
| 160 | } |
| 161 | |
| 162 | send->s_page_list = ib_alloc_fast_reg_page_list( |
| 163 | ic->i_cm_id->device, fastreg_message_size); |
| 164 | if (IS_ERR(send->s_page_list)) { |
| 165 | printk(KERN_WARNING "RDS/IW: ib_alloc_fast_reg_page_list failed\n"); |
| 166 | break; |
| 167 | } |
| 168 | } |
| 169 | } |
| 170 | |
| 171 | void rds_iw_send_clear_ring(struct rds_iw_connection *ic) |
| 172 | { |
| 173 | struct rds_iw_send_work *send; |
| 174 | u32 i; |
| 175 | |
| 176 | for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) { |
| 177 | BUG_ON(!send->s_mr); |
| 178 | ib_dereg_mr(send->s_mr); |
| 179 | BUG_ON(!send->s_page_list); |
| 180 | ib_free_fast_reg_page_list(send->s_page_list); |
| 181 | if (send->s_wr.opcode == 0xdead) |
| 182 | continue; |
| 183 | if (send->s_rm) |
| 184 | rds_iw_send_unmap_rm(ic, send, IB_WC_WR_FLUSH_ERR); |
| 185 | if (send->s_op) |
| 186 | rds_iw_send_unmap_rdma(ic, send->s_op); |
| 187 | } |
| 188 | } |
| 189 | |
| 190 | /* |
| 191 | * The _oldest/_free ring operations here race cleanly with the alloc/unalloc |
| 192 | * operations performed in the send path. As the sender allocs and potentially |
| 193 | * unallocs the next free entry in the ring it doesn't alter which is |
| 194 | * the next to be freed, which is what this is concerned with. |
| 195 | */ |
| 196 | void rds_iw_send_cq_comp_handler(struct ib_cq *cq, void *context) |
| 197 | { |
| 198 | struct rds_connection *conn = context; |
| 199 | struct rds_iw_connection *ic = conn->c_transport_data; |
| 200 | struct ib_wc wc; |
| 201 | struct rds_iw_send_work *send; |
| 202 | u32 completed; |
| 203 | u32 oldest; |
| 204 | u32 i; |
| 205 | int ret; |
| 206 | |
| 207 | rdsdebug("cq %p conn %p\n", cq, conn); |
| 208 | rds_iw_stats_inc(s_iw_tx_cq_call); |
| 209 | ret = ib_req_notify_cq(cq, IB_CQ_NEXT_COMP); |
| 210 | if (ret) |
| 211 | rdsdebug("ib_req_notify_cq send failed: %d\n", ret); |
| 212 | |
| 213 | while (ib_poll_cq(cq, 1, &wc) > 0) { |
| 214 | rdsdebug("wc wr_id 0x%llx status %u byte_len %u imm_data %u\n", |
| 215 | (unsigned long long)wc.wr_id, wc.status, wc.byte_len, |
| 216 | be32_to_cpu(wc.ex.imm_data)); |
| 217 | rds_iw_stats_inc(s_iw_tx_cq_event); |
| 218 | |
| 219 | if (wc.status != IB_WC_SUCCESS) { |
| 220 | printk(KERN_ERR "WC Error: status = %d opcode = %d\n", wc.status, wc.opcode); |
| 221 | break; |
| 222 | } |
| 223 | |
| 224 | if (wc.opcode == IB_WC_LOCAL_INV && wc.wr_id == RDS_IW_LOCAL_INV_WR_ID) { |
| 225 | ic->i_fastreg_posted = 0; |
| 226 | continue; |
| 227 | } |
| 228 | |
| 229 | if (wc.opcode == IB_WC_FAST_REG_MR && wc.wr_id == RDS_IW_FAST_REG_WR_ID) { |
| 230 | ic->i_fastreg_posted = 1; |
| 231 | continue; |
| 232 | } |
| 233 | |
| 234 | if (wc.wr_id == RDS_IW_ACK_WR_ID) { |
| 235 | if (ic->i_ack_queued + HZ/2 < jiffies) |
| 236 | rds_iw_stats_inc(s_iw_tx_stalled); |
| 237 | rds_iw_ack_send_complete(ic); |
| 238 | continue; |
| 239 | } |
| 240 | |
| 241 | oldest = rds_iw_ring_oldest(&ic->i_send_ring); |
| 242 | |
| 243 | completed = rds_iw_ring_completed(&ic->i_send_ring, wc.wr_id, oldest); |
| 244 | |
| 245 | for (i = 0; i < completed; i++) { |
| 246 | send = &ic->i_sends[oldest]; |
| 247 | |
| 248 | /* In the error case, wc.opcode sometimes contains garbage */ |
| 249 | switch (send->s_wr.opcode) { |
| 250 | case IB_WR_SEND: |
| 251 | if (send->s_rm) |
| 252 | rds_iw_send_unmap_rm(ic, send, wc.status); |
| 253 | break; |
| 254 | case IB_WR_FAST_REG_MR: |
| 255 | case IB_WR_RDMA_WRITE: |
| 256 | case IB_WR_RDMA_READ: |
| 257 | case IB_WR_RDMA_READ_WITH_INV: |
| 258 | /* Nothing to be done - the SG list will be unmapped |
| 259 | * when the SEND completes. */ |
| 260 | break; |
| 261 | default: |
| 262 | if (printk_ratelimit()) |
| 263 | printk(KERN_NOTICE |
| 264 | "RDS/IW: %s: unexpected opcode 0x%x in WR!\n", |
| 265 | __func__, send->s_wr.opcode); |
| 266 | break; |
| 267 | } |
| 268 | |
| 269 | send->s_wr.opcode = 0xdead; |
| 270 | send->s_wr.num_sge = 1; |
| 271 | if (send->s_queued + HZ/2 < jiffies) |
| 272 | rds_iw_stats_inc(s_iw_tx_stalled); |
| 273 | |
| 274 | /* If a RDMA operation produced an error, signal this right |
| 275 | * away. If we don't, the subsequent SEND that goes with this |
| 276 | * RDMA will be canceled with ERR_WFLUSH, and the application |
| 277 | * never learn that the RDMA failed. */ |
| 278 | if (unlikely(wc.status == IB_WC_REM_ACCESS_ERR && send->s_op)) { |
| 279 | struct rds_message *rm; |
| 280 | |
| 281 | rm = rds_send_get_message(conn, send->s_op); |
| 282 | if (rm) |
| 283 | rds_iw_send_rdma_complete(rm, wc.status); |
| 284 | } |
| 285 | |
| 286 | oldest = (oldest + 1) % ic->i_send_ring.w_nr; |
| 287 | } |
| 288 | |
| 289 | rds_iw_ring_free(&ic->i_send_ring, completed); |
| 290 | |
Joe Perches | f64f9e7 | 2009-11-29 16:55:45 -0800 | [diff] [blame] | 291 | if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags) || |
| 292 | test_bit(0, &conn->c_map_queued)) |
Andy Grover | fcd8b7c | 2009-02-24 15:30:36 +0000 | [diff] [blame] | 293 | queue_delayed_work(rds_wq, &conn->c_send_w, 0); |
| 294 | |
| 295 | /* We expect errors as the qp is drained during shutdown */ |
| 296 | if (wc.status != IB_WC_SUCCESS && rds_conn_up(conn)) { |
| 297 | rds_iw_conn_error(conn, |
| 298 | "send completion on %pI4 " |
| 299 | "had status %u, disconnecting and reconnecting\n", |
| 300 | &conn->c_faddr, wc.status); |
| 301 | } |
| 302 | } |
| 303 | } |
| 304 | |
| 305 | /* |
| 306 | * This is the main function for allocating credits when sending |
| 307 | * messages. |
| 308 | * |
| 309 | * Conceptually, we have two counters: |
| 310 | * - send credits: this tells us how many WRs we're allowed |
| 311 | * to submit without overruning the reciever's queue. For |
| 312 | * each SEND WR we post, we decrement this by one. |
| 313 | * |
| 314 | * - posted credits: this tells us how many WRs we recently |
| 315 | * posted to the receive queue. This value is transferred |
| 316 | * to the peer as a "credit update" in a RDS header field. |
| 317 | * Every time we transmit credits to the peer, we subtract |
| 318 | * the amount of transferred credits from this counter. |
| 319 | * |
| 320 | * It is essential that we avoid situations where both sides have |
| 321 | * exhausted their send credits, and are unable to send new credits |
| 322 | * to the peer. We achieve this by requiring that we send at least |
| 323 | * one credit update to the peer before exhausting our credits. |
| 324 | * When new credits arrive, we subtract one credit that is withheld |
| 325 | * until we've posted new buffers and are ready to transmit these |
| 326 | * credits (see rds_iw_send_add_credits below). |
| 327 | * |
| 328 | * The RDS send code is essentially single-threaded; rds_send_xmit |
| 329 | * grabs c_send_lock to ensure exclusive access to the send ring. |
| 330 | * However, the ACK sending code is independent and can race with |
| 331 | * message SENDs. |
| 332 | * |
| 333 | * In the send path, we need to update the counters for send credits |
| 334 | * and the counter of posted buffers atomically - when we use the |
| 335 | * last available credit, we cannot allow another thread to race us |
| 336 | * and grab the posted credits counter. Hence, we have to use a |
| 337 | * spinlock to protect the credit counter, or use atomics. |
| 338 | * |
| 339 | * Spinlocks shared between the send and the receive path are bad, |
| 340 | * because they create unnecessary delays. An early implementation |
| 341 | * using a spinlock showed a 5% degradation in throughput at some |
| 342 | * loads. |
| 343 | * |
| 344 | * This implementation avoids spinlocks completely, putting both |
| 345 | * counters into a single atomic, and updating that atomic using |
| 346 | * atomic_add (in the receive path, when receiving fresh credits), |
| 347 | * and using atomic_cmpxchg when updating the two counters. |
| 348 | */ |
| 349 | int rds_iw_send_grab_credits(struct rds_iw_connection *ic, |
Steve Wise | 7b70d03 | 2009-04-09 14:09:39 +0000 | [diff] [blame] | 350 | u32 wanted, u32 *adv_credits, int need_posted, int max_posted) |
Andy Grover | fcd8b7c | 2009-02-24 15:30:36 +0000 | [diff] [blame] | 351 | { |
| 352 | unsigned int avail, posted, got = 0, advertise; |
| 353 | long oldval, newval; |
| 354 | |
| 355 | *adv_credits = 0; |
| 356 | if (!ic->i_flowctl) |
| 357 | return wanted; |
| 358 | |
| 359 | try_again: |
| 360 | advertise = 0; |
| 361 | oldval = newval = atomic_read(&ic->i_credits); |
| 362 | posted = IB_GET_POST_CREDITS(oldval); |
| 363 | avail = IB_GET_SEND_CREDITS(oldval); |
| 364 | |
| 365 | rdsdebug("rds_iw_send_grab_credits(%u): credits=%u posted=%u\n", |
| 366 | wanted, avail, posted); |
| 367 | |
| 368 | /* The last credit must be used to send a credit update. */ |
| 369 | if (avail && !posted) |
| 370 | avail--; |
| 371 | |
| 372 | if (avail < wanted) { |
| 373 | struct rds_connection *conn = ic->i_cm_id->context; |
| 374 | |
| 375 | /* Oops, there aren't that many credits left! */ |
| 376 | set_bit(RDS_LL_SEND_FULL, &conn->c_flags); |
| 377 | got = avail; |
| 378 | } else { |
| 379 | /* Sometimes you get what you want, lalala. */ |
| 380 | got = wanted; |
| 381 | } |
| 382 | newval -= IB_SET_SEND_CREDITS(got); |
| 383 | |
| 384 | /* |
| 385 | * If need_posted is non-zero, then the caller wants |
| 386 | * the posted regardless of whether any send credits are |
| 387 | * available. |
| 388 | */ |
| 389 | if (posted && (got || need_posted)) { |
Steve Wise | 7b70d03 | 2009-04-09 14:09:39 +0000 | [diff] [blame] | 390 | advertise = min_t(unsigned int, posted, max_posted); |
Andy Grover | fcd8b7c | 2009-02-24 15:30:36 +0000 | [diff] [blame] | 391 | newval -= IB_SET_POST_CREDITS(advertise); |
| 392 | } |
| 393 | |
| 394 | /* Finally bill everything */ |
| 395 | if (atomic_cmpxchg(&ic->i_credits, oldval, newval) != oldval) |
| 396 | goto try_again; |
| 397 | |
| 398 | *adv_credits = advertise; |
| 399 | return got; |
| 400 | } |
| 401 | |
| 402 | void rds_iw_send_add_credits(struct rds_connection *conn, unsigned int credits) |
| 403 | { |
| 404 | struct rds_iw_connection *ic = conn->c_transport_data; |
| 405 | |
| 406 | if (credits == 0) |
| 407 | return; |
| 408 | |
| 409 | rdsdebug("rds_iw_send_add_credits(%u): current=%u%s\n", |
| 410 | credits, |
| 411 | IB_GET_SEND_CREDITS(atomic_read(&ic->i_credits)), |
| 412 | test_bit(RDS_LL_SEND_FULL, &conn->c_flags) ? ", ll_send_full" : ""); |
| 413 | |
| 414 | atomic_add(IB_SET_SEND_CREDITS(credits), &ic->i_credits); |
| 415 | if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags)) |
| 416 | queue_delayed_work(rds_wq, &conn->c_send_w, 0); |
| 417 | |
| 418 | WARN_ON(IB_GET_SEND_CREDITS(credits) >= 16384); |
| 419 | |
| 420 | rds_iw_stats_inc(s_iw_rx_credit_updates); |
| 421 | } |
| 422 | |
| 423 | void rds_iw_advertise_credits(struct rds_connection *conn, unsigned int posted) |
| 424 | { |
| 425 | struct rds_iw_connection *ic = conn->c_transport_data; |
| 426 | |
| 427 | if (posted == 0) |
| 428 | return; |
| 429 | |
| 430 | atomic_add(IB_SET_POST_CREDITS(posted), &ic->i_credits); |
| 431 | |
| 432 | /* Decide whether to send an update to the peer now. |
| 433 | * If we would send a credit update for every single buffer we |
| 434 | * post, we would end up with an ACK storm (ACK arrives, |
| 435 | * consumes buffer, we refill the ring, send ACK to remote |
| 436 | * advertising the newly posted buffer... ad inf) |
| 437 | * |
| 438 | * Performance pretty much depends on how often we send |
| 439 | * credit updates - too frequent updates mean lots of ACKs. |
| 440 | * Too infrequent updates, and the peer will run out of |
| 441 | * credits and has to throttle. |
| 442 | * For the time being, 16 seems to be a good compromise. |
| 443 | */ |
| 444 | if (IB_GET_POST_CREDITS(atomic_read(&ic->i_credits)) >= 16) |
| 445 | set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); |
| 446 | } |
| 447 | |
| 448 | static inline void |
| 449 | rds_iw_xmit_populate_wr(struct rds_iw_connection *ic, |
| 450 | struct rds_iw_send_work *send, unsigned int pos, |
| 451 | unsigned long buffer, unsigned int length, |
| 452 | int send_flags) |
| 453 | { |
| 454 | struct ib_sge *sge; |
| 455 | |
| 456 | WARN_ON(pos != send - ic->i_sends); |
| 457 | |
| 458 | send->s_wr.send_flags = send_flags; |
| 459 | send->s_wr.opcode = IB_WR_SEND; |
| 460 | send->s_wr.num_sge = 2; |
| 461 | send->s_wr.next = NULL; |
| 462 | send->s_queued = jiffies; |
| 463 | send->s_op = NULL; |
| 464 | |
| 465 | if (length != 0) { |
| 466 | sge = rds_iw_data_sge(ic, send->s_sge); |
| 467 | sge->addr = buffer; |
| 468 | sge->length = length; |
| 469 | sge->lkey = rds_iw_local_dma_lkey(ic); |
| 470 | |
| 471 | sge = rds_iw_header_sge(ic, send->s_sge); |
| 472 | } else { |
| 473 | /* We're sending a packet with no payload. There is only |
| 474 | * one SGE */ |
| 475 | send->s_wr.num_sge = 1; |
| 476 | sge = &send->s_sge[0]; |
| 477 | } |
| 478 | |
| 479 | sge->addr = ic->i_send_hdrs_dma + (pos * sizeof(struct rds_header)); |
| 480 | sge->length = sizeof(struct rds_header); |
| 481 | sge->lkey = rds_iw_local_dma_lkey(ic); |
| 482 | } |
| 483 | |
| 484 | /* |
| 485 | * This can be called multiple times for a given message. The first time |
| 486 | * we see a message we map its scatterlist into the IB device so that |
| 487 | * we can provide that mapped address to the IB scatter gather entries |
| 488 | * in the IB work requests. We translate the scatterlist into a series |
| 489 | * of work requests that fragment the message. These work requests complete |
| 490 | * in order so we pass ownership of the message to the completion handler |
| 491 | * once we send the final fragment. |
| 492 | * |
| 493 | * The RDS core uses the c_send_lock to only enter this function once |
| 494 | * per connection. This makes sure that the tx ring alloc/unalloc pairs |
| 495 | * don't get out of sync and confuse the ring. |
| 496 | */ |
| 497 | int rds_iw_xmit(struct rds_connection *conn, struct rds_message *rm, |
| 498 | unsigned int hdr_off, unsigned int sg, unsigned int off) |
| 499 | { |
| 500 | struct rds_iw_connection *ic = conn->c_transport_data; |
| 501 | struct ib_device *dev = ic->i_cm_id->device; |
| 502 | struct rds_iw_send_work *send = NULL; |
| 503 | struct rds_iw_send_work *first; |
| 504 | struct rds_iw_send_work *prev; |
| 505 | struct ib_send_wr *failed_wr; |
| 506 | struct scatterlist *scat; |
| 507 | u32 pos; |
| 508 | u32 i; |
| 509 | u32 work_alloc; |
| 510 | u32 credit_alloc; |
| 511 | u32 posted; |
| 512 | u32 adv_credits = 0; |
| 513 | int send_flags = 0; |
| 514 | int sent; |
| 515 | int ret; |
| 516 | int flow_controlled = 0; |
| 517 | |
| 518 | BUG_ON(off % RDS_FRAG_SIZE); |
| 519 | BUG_ON(hdr_off != 0 && hdr_off != sizeof(struct rds_header)); |
| 520 | |
| 521 | /* Fastreg support */ |
Joe Perches | f64f9e7 | 2009-11-29 16:55:45 -0800 | [diff] [blame] | 522 | if (rds_rdma_cookie_key(rm->m_rdma_cookie) && !ic->i_fastreg_posted) { |
Andy Grover | fcd8b7c | 2009-02-24 15:30:36 +0000 | [diff] [blame] | 523 | ret = -EAGAIN; |
| 524 | goto out; |
| 525 | } |
| 526 | |
| 527 | /* FIXME we may overallocate here */ |
| 528 | if (be32_to_cpu(rm->m_inc.i_hdr.h_len) == 0) |
| 529 | i = 1; |
| 530 | else |
| 531 | i = ceil(be32_to_cpu(rm->m_inc.i_hdr.h_len), RDS_FRAG_SIZE); |
| 532 | |
| 533 | work_alloc = rds_iw_ring_alloc(&ic->i_send_ring, i, &pos); |
| 534 | if (work_alloc == 0) { |
| 535 | set_bit(RDS_LL_SEND_FULL, &conn->c_flags); |
| 536 | rds_iw_stats_inc(s_iw_tx_ring_full); |
| 537 | ret = -ENOMEM; |
| 538 | goto out; |
| 539 | } |
| 540 | |
| 541 | credit_alloc = work_alloc; |
| 542 | if (ic->i_flowctl) { |
Steve Wise | 7b70d03 | 2009-04-09 14:09:39 +0000 | [diff] [blame] | 543 | credit_alloc = rds_iw_send_grab_credits(ic, work_alloc, &posted, 0, RDS_MAX_ADV_CREDIT); |
Andy Grover | fcd8b7c | 2009-02-24 15:30:36 +0000 | [diff] [blame] | 544 | adv_credits += posted; |
| 545 | if (credit_alloc < work_alloc) { |
| 546 | rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc - credit_alloc); |
| 547 | work_alloc = credit_alloc; |
| 548 | flow_controlled++; |
| 549 | } |
| 550 | if (work_alloc == 0) { |
Steve Wise | d39e060 | 2009-04-09 14:09:38 +0000 | [diff] [blame] | 551 | set_bit(RDS_LL_SEND_FULL, &conn->c_flags); |
Andy Grover | fcd8b7c | 2009-02-24 15:30:36 +0000 | [diff] [blame] | 552 | rds_iw_stats_inc(s_iw_tx_throttle); |
| 553 | ret = -ENOMEM; |
| 554 | goto out; |
| 555 | } |
| 556 | } |
| 557 | |
| 558 | /* map the message the first time we see it */ |
| 559 | if (ic->i_rm == NULL) { |
| 560 | /* |
| 561 | printk(KERN_NOTICE "rds_iw_xmit prep msg dport=%u flags=0x%x len=%d\n", |
| 562 | be16_to_cpu(rm->m_inc.i_hdr.h_dport), |
| 563 | rm->m_inc.i_hdr.h_flags, |
| 564 | be32_to_cpu(rm->m_inc.i_hdr.h_len)); |
| 565 | */ |
| 566 | if (rm->m_nents) { |
| 567 | rm->m_count = ib_dma_map_sg(dev, |
| 568 | rm->m_sg, rm->m_nents, DMA_TO_DEVICE); |
| 569 | rdsdebug("ic %p mapping rm %p: %d\n", ic, rm, rm->m_count); |
| 570 | if (rm->m_count == 0) { |
| 571 | rds_iw_stats_inc(s_iw_tx_sg_mapping_failure); |
| 572 | rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc); |
| 573 | ret = -ENOMEM; /* XXX ? */ |
| 574 | goto out; |
| 575 | } |
| 576 | } else { |
| 577 | rm->m_count = 0; |
| 578 | } |
| 579 | |
| 580 | ic->i_unsignaled_wrs = rds_iw_sysctl_max_unsig_wrs; |
| 581 | ic->i_unsignaled_bytes = rds_iw_sysctl_max_unsig_bytes; |
| 582 | rds_message_addref(rm); |
| 583 | ic->i_rm = rm; |
| 584 | |
| 585 | /* Finalize the header */ |
| 586 | if (test_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags)) |
| 587 | rm->m_inc.i_hdr.h_flags |= RDS_FLAG_ACK_REQUIRED; |
| 588 | if (test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) |
| 589 | rm->m_inc.i_hdr.h_flags |= RDS_FLAG_RETRANSMITTED; |
| 590 | |
| 591 | /* If it has a RDMA op, tell the peer we did it. This is |
| 592 | * used by the peer to release use-once RDMA MRs. */ |
| 593 | if (rm->m_rdma_op) { |
| 594 | struct rds_ext_header_rdma ext_hdr; |
| 595 | |
| 596 | ext_hdr.h_rdma_rkey = cpu_to_be32(rm->m_rdma_op->r_key); |
| 597 | rds_message_add_extension(&rm->m_inc.i_hdr, |
| 598 | RDS_EXTHDR_RDMA, &ext_hdr, sizeof(ext_hdr)); |
| 599 | } |
| 600 | if (rm->m_rdma_cookie) { |
| 601 | rds_message_add_rdma_dest_extension(&rm->m_inc.i_hdr, |
| 602 | rds_rdma_cookie_key(rm->m_rdma_cookie), |
| 603 | rds_rdma_cookie_offset(rm->m_rdma_cookie)); |
| 604 | } |
| 605 | |
| 606 | /* Note - rds_iw_piggyb_ack clears the ACK_REQUIRED bit, so |
| 607 | * we should not do this unless we have a chance of at least |
| 608 | * sticking the header into the send ring. Which is why we |
| 609 | * should call rds_iw_ring_alloc first. */ |
| 610 | rm->m_inc.i_hdr.h_ack = cpu_to_be64(rds_iw_piggyb_ack(ic)); |
| 611 | rds_message_make_checksum(&rm->m_inc.i_hdr); |
| 612 | |
| 613 | /* |
| 614 | * Update adv_credits since we reset the ACK_REQUIRED bit. |
| 615 | */ |
Steve Wise | 7b70d03 | 2009-04-09 14:09:39 +0000 | [diff] [blame] | 616 | rds_iw_send_grab_credits(ic, 0, &posted, 1, RDS_MAX_ADV_CREDIT - adv_credits); |
Andy Grover | fcd8b7c | 2009-02-24 15:30:36 +0000 | [diff] [blame] | 617 | adv_credits += posted; |
| 618 | BUG_ON(adv_credits > 255); |
Andy Grover | 735f61e | 2010-03-11 13:49:55 +0000 | [diff] [blame] | 619 | } |
Andy Grover | fcd8b7c | 2009-02-24 15:30:36 +0000 | [diff] [blame] | 620 | |
| 621 | send = &ic->i_sends[pos]; |
| 622 | first = send; |
| 623 | prev = NULL; |
| 624 | scat = &rm->m_sg[sg]; |
| 625 | sent = 0; |
| 626 | i = 0; |
| 627 | |
| 628 | /* Sometimes you want to put a fence between an RDMA |
| 629 | * READ and the following SEND. |
| 630 | * We could either do this all the time |
| 631 | * or when requested by the user. Right now, we let |
| 632 | * the application choose. |
| 633 | */ |
| 634 | if (rm->m_rdma_op && rm->m_rdma_op->r_fence) |
| 635 | send_flags = IB_SEND_FENCE; |
| 636 | |
| 637 | /* |
| 638 | * We could be copying the header into the unused tail of the page. |
| 639 | * That would need to be changed in the future when those pages might |
| 640 | * be mapped userspace pages or page cache pages. So instead we always |
| 641 | * use a second sge and our long-lived ring of mapped headers. We send |
| 642 | * the header after the data so that the data payload can be aligned on |
| 643 | * the receiver. |
| 644 | */ |
| 645 | |
| 646 | /* handle a 0-len message */ |
| 647 | if (be32_to_cpu(rm->m_inc.i_hdr.h_len) == 0) { |
| 648 | rds_iw_xmit_populate_wr(ic, send, pos, 0, 0, send_flags); |
| 649 | goto add_header; |
| 650 | } |
| 651 | |
| 652 | /* if there's data reference it with a chain of work reqs */ |
| 653 | for (; i < work_alloc && scat != &rm->m_sg[rm->m_count]; i++) { |
| 654 | unsigned int len; |
| 655 | |
| 656 | send = &ic->i_sends[pos]; |
| 657 | |
| 658 | len = min(RDS_FRAG_SIZE, ib_sg_dma_len(dev, scat) - off); |
| 659 | rds_iw_xmit_populate_wr(ic, send, pos, |
| 660 | ib_sg_dma_address(dev, scat) + off, len, |
| 661 | send_flags); |
| 662 | |
| 663 | /* |
| 664 | * We want to delay signaling completions just enough to get |
| 665 | * the batching benefits but not so much that we create dead time |
| 666 | * on the wire. |
| 667 | */ |
| 668 | if (ic->i_unsignaled_wrs-- == 0) { |
| 669 | ic->i_unsignaled_wrs = rds_iw_sysctl_max_unsig_wrs; |
| 670 | send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED; |
| 671 | } |
| 672 | |
| 673 | ic->i_unsignaled_bytes -= len; |
| 674 | if (ic->i_unsignaled_bytes <= 0) { |
| 675 | ic->i_unsignaled_bytes = rds_iw_sysctl_max_unsig_bytes; |
| 676 | send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED; |
| 677 | } |
| 678 | |
| 679 | /* |
| 680 | * Always signal the last one if we're stopping due to flow control. |
| 681 | */ |
| 682 | if (flow_controlled && i == (work_alloc-1)) |
| 683 | send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED; |
| 684 | |
| 685 | rdsdebug("send %p wr %p num_sge %u next %p\n", send, |
| 686 | &send->s_wr, send->s_wr.num_sge, send->s_wr.next); |
| 687 | |
| 688 | sent += len; |
| 689 | off += len; |
| 690 | if (off == ib_sg_dma_len(dev, scat)) { |
| 691 | scat++; |
| 692 | off = 0; |
| 693 | } |
| 694 | |
| 695 | add_header: |
| 696 | /* Tack on the header after the data. The header SGE should already |
| 697 | * have been set up to point to the right header buffer. */ |
| 698 | memcpy(&ic->i_send_hdrs[pos], &rm->m_inc.i_hdr, sizeof(struct rds_header)); |
| 699 | |
| 700 | if (0) { |
| 701 | struct rds_header *hdr = &ic->i_send_hdrs[pos]; |
| 702 | |
| 703 | printk(KERN_NOTICE "send WR dport=%u flags=0x%x len=%d\n", |
| 704 | be16_to_cpu(hdr->h_dport), |
| 705 | hdr->h_flags, |
| 706 | be32_to_cpu(hdr->h_len)); |
| 707 | } |
| 708 | if (adv_credits) { |
| 709 | struct rds_header *hdr = &ic->i_send_hdrs[pos]; |
| 710 | |
| 711 | /* add credit and redo the header checksum */ |
| 712 | hdr->h_credit = adv_credits; |
| 713 | rds_message_make_checksum(hdr); |
| 714 | adv_credits = 0; |
| 715 | rds_iw_stats_inc(s_iw_tx_credit_updates); |
| 716 | } |
| 717 | |
| 718 | if (prev) |
| 719 | prev->s_wr.next = &send->s_wr; |
| 720 | prev = send; |
| 721 | |
| 722 | pos = (pos + 1) % ic->i_send_ring.w_nr; |
| 723 | } |
| 724 | |
| 725 | /* Account the RDS header in the number of bytes we sent, but just once. |
| 726 | * The caller has no concept of fragmentation. */ |
| 727 | if (hdr_off == 0) |
| 728 | sent += sizeof(struct rds_header); |
| 729 | |
| 730 | /* if we finished the message then send completion owns it */ |
| 731 | if (scat == &rm->m_sg[rm->m_count]) { |
| 732 | prev->s_rm = ic->i_rm; |
| 733 | prev->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED; |
| 734 | ic->i_rm = NULL; |
| 735 | } |
| 736 | |
| 737 | if (i < work_alloc) { |
| 738 | rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc - i); |
| 739 | work_alloc = i; |
| 740 | } |
| 741 | if (ic->i_flowctl && i < credit_alloc) |
| 742 | rds_iw_send_add_credits(conn, credit_alloc - i); |
| 743 | |
| 744 | /* XXX need to worry about failed_wr and partial sends. */ |
| 745 | failed_wr = &first->s_wr; |
| 746 | ret = ib_post_send(ic->i_cm_id->qp, &first->s_wr, &failed_wr); |
| 747 | rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic, |
| 748 | first, &first->s_wr, ret, failed_wr); |
| 749 | BUG_ON(failed_wr != &first->s_wr); |
| 750 | if (ret) { |
| 751 | printk(KERN_WARNING "RDS/IW: ib_post_send to %pI4 " |
| 752 | "returned %d\n", &conn->c_faddr, ret); |
| 753 | rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc); |
| 754 | if (prev->s_rm) { |
| 755 | ic->i_rm = prev->s_rm; |
| 756 | prev->s_rm = NULL; |
| 757 | } |
| 758 | goto out; |
| 759 | } |
| 760 | |
| 761 | ret = sent; |
| 762 | out: |
| 763 | BUG_ON(adv_credits); |
| 764 | return ret; |
| 765 | } |
| 766 | |
| 767 | static void rds_iw_build_send_fastreg(struct rds_iw_device *rds_iwdev, struct rds_iw_connection *ic, struct rds_iw_send_work *send, int nent, int len, u64 sg_addr) |
| 768 | { |
| 769 | BUG_ON(nent > send->s_page_list->max_page_list_len); |
| 770 | /* |
| 771 | * Perform a WR for the fast_reg_mr. Each individual page |
| 772 | * in the sg list is added to the fast reg page list and placed |
| 773 | * inside the fast_reg_mr WR. |
| 774 | */ |
| 775 | send->s_wr.opcode = IB_WR_FAST_REG_MR; |
| 776 | send->s_wr.wr.fast_reg.length = len; |
| 777 | send->s_wr.wr.fast_reg.rkey = send->s_mr->rkey; |
| 778 | send->s_wr.wr.fast_reg.page_list = send->s_page_list; |
| 779 | send->s_wr.wr.fast_reg.page_list_len = nent; |
Andy Grover | 404bb72 | 2009-07-17 13:13:34 +0000 | [diff] [blame] | 780 | send->s_wr.wr.fast_reg.page_shift = PAGE_SHIFT; |
Andy Grover | fcd8b7c | 2009-02-24 15:30:36 +0000 | [diff] [blame] | 781 | send->s_wr.wr.fast_reg.access_flags = IB_ACCESS_REMOTE_WRITE; |
| 782 | send->s_wr.wr.fast_reg.iova_start = sg_addr; |
| 783 | |
| 784 | ib_update_fast_reg_key(send->s_mr, send->s_remap_count++); |
| 785 | } |
| 786 | |
| 787 | int rds_iw_xmit_rdma(struct rds_connection *conn, struct rds_rdma_op *op) |
| 788 | { |
| 789 | struct rds_iw_connection *ic = conn->c_transport_data; |
| 790 | struct rds_iw_send_work *send = NULL; |
| 791 | struct rds_iw_send_work *first; |
| 792 | struct rds_iw_send_work *prev; |
| 793 | struct ib_send_wr *failed_wr; |
| 794 | struct rds_iw_device *rds_iwdev; |
| 795 | struct scatterlist *scat; |
| 796 | unsigned long len; |
| 797 | u64 remote_addr = op->r_remote_addr; |
| 798 | u32 pos, fr_pos; |
| 799 | u32 work_alloc; |
| 800 | u32 i; |
| 801 | u32 j; |
| 802 | int sent; |
| 803 | int ret; |
| 804 | int num_sge; |
| 805 | |
| 806 | rds_iwdev = ib_get_client_data(ic->i_cm_id->device, &rds_iw_client); |
| 807 | |
| 808 | /* map the message the first time we see it */ |
| 809 | if (!op->r_mapped) { |
| 810 | op->r_count = ib_dma_map_sg(ic->i_cm_id->device, |
| 811 | op->r_sg, op->r_nents, (op->r_write) ? |
| 812 | DMA_TO_DEVICE : DMA_FROM_DEVICE); |
| 813 | rdsdebug("ic %p mapping op %p: %d\n", ic, op, op->r_count); |
| 814 | if (op->r_count == 0) { |
| 815 | rds_iw_stats_inc(s_iw_tx_sg_mapping_failure); |
| 816 | ret = -ENOMEM; /* XXX ? */ |
| 817 | goto out; |
| 818 | } |
| 819 | |
| 820 | op->r_mapped = 1; |
| 821 | } |
| 822 | |
| 823 | if (!op->r_write) { |
| 824 | /* Alloc space on the send queue for the fastreg */ |
| 825 | work_alloc = rds_iw_ring_alloc(&ic->i_send_ring, 1, &fr_pos); |
| 826 | if (work_alloc != 1) { |
| 827 | rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc); |
| 828 | rds_iw_stats_inc(s_iw_tx_ring_full); |
| 829 | ret = -ENOMEM; |
| 830 | goto out; |
| 831 | } |
| 832 | } |
| 833 | |
| 834 | /* |
| 835 | * Instead of knowing how to return a partial rdma read/write we insist that there |
| 836 | * be enough work requests to send the entire message. |
| 837 | */ |
| 838 | i = ceil(op->r_count, rds_iwdev->max_sge); |
| 839 | |
| 840 | work_alloc = rds_iw_ring_alloc(&ic->i_send_ring, i, &pos); |
| 841 | if (work_alloc != i) { |
| 842 | rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc); |
| 843 | rds_iw_stats_inc(s_iw_tx_ring_full); |
| 844 | ret = -ENOMEM; |
| 845 | goto out; |
| 846 | } |
| 847 | |
| 848 | send = &ic->i_sends[pos]; |
| 849 | if (!op->r_write) { |
| 850 | first = prev = &ic->i_sends[fr_pos]; |
| 851 | } else { |
| 852 | first = send; |
| 853 | prev = NULL; |
| 854 | } |
| 855 | scat = &op->r_sg[0]; |
| 856 | sent = 0; |
| 857 | num_sge = op->r_count; |
| 858 | |
| 859 | for (i = 0; i < work_alloc && scat != &op->r_sg[op->r_count]; i++) { |
| 860 | send->s_wr.send_flags = 0; |
| 861 | send->s_queued = jiffies; |
| 862 | |
| 863 | /* |
| 864 | * We want to delay signaling completions just enough to get |
| 865 | * the batching benefits but not so much that we create dead time on the wire. |
| 866 | */ |
| 867 | if (ic->i_unsignaled_wrs-- == 0) { |
| 868 | ic->i_unsignaled_wrs = rds_iw_sysctl_max_unsig_wrs; |
| 869 | send->s_wr.send_flags = IB_SEND_SIGNALED; |
| 870 | } |
| 871 | |
| 872 | /* To avoid the need to have the plumbing to invalidate the fastreg_mr used |
| 873 | * for local access after RDS is finished with it, using |
| 874 | * IB_WR_RDMA_READ_WITH_INV will invalidate it after the read has completed. |
| 875 | */ |
| 876 | if (op->r_write) |
| 877 | send->s_wr.opcode = IB_WR_RDMA_WRITE; |
| 878 | else |
| 879 | send->s_wr.opcode = IB_WR_RDMA_READ_WITH_INV; |
| 880 | |
| 881 | send->s_wr.wr.rdma.remote_addr = remote_addr; |
| 882 | send->s_wr.wr.rdma.rkey = op->r_key; |
| 883 | send->s_op = op; |
| 884 | |
| 885 | if (num_sge > rds_iwdev->max_sge) { |
| 886 | send->s_wr.num_sge = rds_iwdev->max_sge; |
| 887 | num_sge -= rds_iwdev->max_sge; |
| 888 | } else |
| 889 | send->s_wr.num_sge = num_sge; |
| 890 | |
| 891 | send->s_wr.next = NULL; |
| 892 | |
| 893 | if (prev) |
| 894 | prev->s_wr.next = &send->s_wr; |
| 895 | |
| 896 | for (j = 0; j < send->s_wr.num_sge && scat != &op->r_sg[op->r_count]; j++) { |
| 897 | len = ib_sg_dma_len(ic->i_cm_id->device, scat); |
| 898 | |
| 899 | if (send->s_wr.opcode == IB_WR_RDMA_READ_WITH_INV) |
| 900 | send->s_page_list->page_list[j] = ib_sg_dma_address(ic->i_cm_id->device, scat); |
| 901 | else { |
| 902 | send->s_sge[j].addr = ib_sg_dma_address(ic->i_cm_id->device, scat); |
| 903 | send->s_sge[j].length = len; |
| 904 | send->s_sge[j].lkey = rds_iw_local_dma_lkey(ic); |
| 905 | } |
| 906 | |
| 907 | sent += len; |
| 908 | rdsdebug("ic %p sent %d remote_addr %llu\n", ic, sent, remote_addr); |
| 909 | remote_addr += len; |
| 910 | |
| 911 | scat++; |
| 912 | } |
| 913 | |
| 914 | if (send->s_wr.opcode == IB_WR_RDMA_READ_WITH_INV) { |
| 915 | send->s_wr.num_sge = 1; |
| 916 | send->s_sge[0].addr = conn->c_xmit_rm->m_rs->rs_user_addr; |
| 917 | send->s_sge[0].length = conn->c_xmit_rm->m_rs->rs_user_bytes; |
| 918 | send->s_sge[0].lkey = ic->i_sends[fr_pos].s_mr->lkey; |
| 919 | } |
| 920 | |
| 921 | rdsdebug("send %p wr %p num_sge %u next %p\n", send, |
| 922 | &send->s_wr, send->s_wr.num_sge, send->s_wr.next); |
| 923 | |
| 924 | prev = send; |
| 925 | if (++send == &ic->i_sends[ic->i_send_ring.w_nr]) |
| 926 | send = ic->i_sends; |
| 927 | } |
| 928 | |
| 929 | /* if we finished the message then send completion owns it */ |
| 930 | if (scat == &op->r_sg[op->r_count]) |
| 931 | first->s_wr.send_flags = IB_SEND_SIGNALED; |
| 932 | |
| 933 | if (i < work_alloc) { |
| 934 | rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc - i); |
| 935 | work_alloc = i; |
| 936 | } |
| 937 | |
| 938 | /* On iWARP, local memory access by a remote system (ie, RDMA Read) is not |
| 939 | * recommended. Putting the lkey on the wire is a security hole, as it can |
| 940 | * allow for memory access to all of memory on the remote system. Some |
| 941 | * adapters do not allow using the lkey for this at all. To bypass this use a |
| 942 | * fastreg_mr (or possibly a dma_mr) |
| 943 | */ |
| 944 | if (!op->r_write) { |
| 945 | rds_iw_build_send_fastreg(rds_iwdev, ic, &ic->i_sends[fr_pos], |
| 946 | op->r_count, sent, conn->c_xmit_rm->m_rs->rs_user_addr); |
| 947 | work_alloc++; |
| 948 | } |
| 949 | |
| 950 | failed_wr = &first->s_wr; |
| 951 | ret = ib_post_send(ic->i_cm_id->qp, &first->s_wr, &failed_wr); |
| 952 | rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic, |
| 953 | first, &first->s_wr, ret, failed_wr); |
| 954 | BUG_ON(failed_wr != &first->s_wr); |
| 955 | if (ret) { |
| 956 | printk(KERN_WARNING "RDS/IW: rdma ib_post_send to %pI4 " |
| 957 | "returned %d\n", &conn->c_faddr, ret); |
| 958 | rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc); |
| 959 | goto out; |
| 960 | } |
| 961 | |
| 962 | out: |
| 963 | return ret; |
| 964 | } |
| 965 | |
| 966 | void rds_iw_xmit_complete(struct rds_connection *conn) |
| 967 | { |
| 968 | struct rds_iw_connection *ic = conn->c_transport_data; |
| 969 | |
| 970 | /* We may have a pending ACK or window update we were unable |
| 971 | * to send previously (due to flow control). Try again. */ |
| 972 | rds_iw_attempt_ack(ic); |
| 973 | } |