send.c revision 9de0864cf55927a7383b5ba6e48834ff3ef053de
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/gfp.h> 35#include <net/sock.h> 36#include <linux/in.h> 37#include <linux/list.h> 38 39#include "rds.h" 40#include "rdma.h" 41 42/* When transmitting messages in rds_send_xmit, we need to emerge from 43 * time to time and briefly release the CPU. Otherwise the softlock watchdog 44 * will kick our shin. 45 * Also, it seems fairer to not let one busy connection stall all the 46 * others. 47 * 48 * send_batch_count is the number of times we'll loop in send_xmit. Setting 49 * it to 0 will restore the old behavior (where we looped until we had 50 * drained the queue). 51 */ 52static int send_batch_count = 64; 53module_param(send_batch_count, int, 0444); 54MODULE_PARM_DESC(send_batch_count, " batch factor when working the send queue"); 55 56/* 57 * Reset the send state. Caller must hold c_send_lock when calling here. 58 */ 59void rds_send_reset(struct rds_connection *conn) 60{ 61 struct rds_message *rm, *tmp; 62 unsigned long flags; 63 64 if (conn->c_xmit_rm) { 65 /* Tell the user the RDMA op is no longer mapped by the 66 * transport. This isn't entirely true (it's flushed out 67 * independently) but as the connection is down, there's 68 * no ongoing RDMA to/from that memory */ 69 rds_message_unmapped(conn->c_xmit_rm); 70 rds_message_put(conn->c_xmit_rm); 71 conn->c_xmit_rm = NULL; 72 } 73 conn->c_xmit_sg = 0; 74 conn->c_xmit_hdr_off = 0; 75 conn->c_xmit_data_off = 0; 76 conn->c_xmit_rdma_sent = 0; 77 78 conn->c_map_queued = 0; 79 80 conn->c_unacked_packets = rds_sysctl_max_unacked_packets; 81 conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes; 82 83 /* Mark messages as retransmissions, and move them to the send q */ 84 spin_lock_irqsave(&conn->c_lock, flags); 85 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) { 86 set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags); 87 set_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags); 88 } 89 list_splice_init(&conn->c_retrans, &conn->c_send_queue); 90 spin_unlock_irqrestore(&conn->c_lock, flags); 91} 92 93/* 94 * We're making the concious trade-off here to only send one message 95 * down the connection at a time. 96 * Pro: 97 * - tx queueing is a simple fifo list 98 * - reassembly is optional and easily done by transports per conn 99 * - no per flow rx lookup at all, straight to the socket 100 * - less per-frag memory and wire overhead 101 * Con: 102 * - queued acks can be delayed behind large messages 103 * Depends: 104 * - small message latency is higher behind queued large messages 105 * - large message latency isn't starved by intervening small sends 106 */ 107int rds_send_xmit(struct rds_connection *conn) 108{ 109 struct rds_message *rm; 110 unsigned long flags; 111 unsigned int tmp; 112 unsigned int send_quota = send_batch_count; 113 struct scatterlist *sg; 114 int ret = 0; 115 int was_empty = 0; 116 LIST_HEAD(to_be_dropped); 117 118 /* 119 * sendmsg calls here after having queued its message on the send 120 * queue. We only have one task feeding the connection at a time. If 121 * another thread is already feeding the queue then we back off. This 122 * avoids blocking the caller and trading per-connection data between 123 * caches per message. 124 * 125 * The sem holder will issue a retry if they notice that someone queued 126 * a message after they stopped walking the send queue but before they 127 * dropped the sem. 128 */ 129 if (!mutex_trylock(&conn->c_send_lock)) { 130 rds_stats_inc(s_send_sem_contention); 131 ret = -ENOMEM; 132 goto out; 133 } 134 135 if (conn->c_trans->xmit_prepare) 136 conn->c_trans->xmit_prepare(conn); 137 138 /* 139 * spin trying to push headers and data down the connection until 140 * the connection doens't make forward progress. 141 */ 142 while (--send_quota) { 143 /* 144 * See if need to send a congestion map update if we're 145 * between sending messages. The send_sem protects our sole 146 * use of c_map_offset and _bytes. 147 * Note this is used only by transports that define a special 148 * xmit_cong_map function. For all others, we create allocate 149 * a cong_map message and treat it just like any other send. 150 */ 151 if (conn->c_map_bytes) { 152 ret = conn->c_trans->xmit_cong_map(conn, conn->c_lcong, 153 conn->c_map_offset); 154 if (ret <= 0) 155 break; 156 157 conn->c_map_offset += ret; 158 conn->c_map_bytes -= ret; 159 if (conn->c_map_bytes) 160 continue; 161 } 162 163 /* If we're done sending the current message, clear the 164 * offset and S/G temporaries. 165 */ 166 rm = conn->c_xmit_rm; 167 if (rm != NULL && 168 conn->c_xmit_hdr_off == sizeof(struct rds_header) && 169 conn->c_xmit_sg == rm->m_nents) { 170 conn->c_xmit_rm = NULL; 171 conn->c_xmit_sg = 0; 172 conn->c_xmit_hdr_off = 0; 173 conn->c_xmit_data_off = 0; 174 conn->c_xmit_rdma_sent = 0; 175 176 /* Release the reference to the previous message. */ 177 rds_message_put(rm); 178 rm = NULL; 179 } 180 181 /* If we're asked to send a cong map update, do so. 182 */ 183 if (rm == NULL && test_and_clear_bit(0, &conn->c_map_queued)) { 184 if (conn->c_trans->xmit_cong_map != NULL) { 185 conn->c_map_offset = 0; 186 conn->c_map_bytes = sizeof(struct rds_header) + 187 RDS_CONG_MAP_BYTES; 188 continue; 189 } 190 191 rm = rds_cong_update_alloc(conn); 192 if (IS_ERR(rm)) { 193 ret = PTR_ERR(rm); 194 break; 195 } 196 197 conn->c_xmit_rm = rm; 198 } 199 200 /* 201 * Grab the next message from the send queue, if there is one. 202 * 203 * c_xmit_rm holds a ref while we're sending this message down 204 * the connction. We can use this ref while holding the 205 * send_sem.. rds_send_reset() is serialized with it. 206 */ 207 if (rm == NULL) { 208 unsigned int len; 209 210 spin_lock_irqsave(&conn->c_lock, flags); 211 212 if (!list_empty(&conn->c_send_queue)) { 213 rm = list_entry(conn->c_send_queue.next, 214 struct rds_message, 215 m_conn_item); 216 rds_message_addref(rm); 217 218 /* 219 * Move the message from the send queue to the retransmit 220 * list right away. 221 */ 222 list_move_tail(&rm->m_conn_item, &conn->c_retrans); 223 } 224 225 spin_unlock_irqrestore(&conn->c_lock, flags); 226 227 if (rm == NULL) { 228 was_empty = 1; 229 break; 230 } 231 232 /* Unfortunately, the way Infiniband deals with 233 * RDMA to a bad MR key is by moving the entire 234 * queue pair to error state. We cold possibly 235 * recover from that, but right now we drop the 236 * connection. 237 * Therefore, we never retransmit messages with RDMA ops. 238 */ 239 if (rm->m_rdma_op && 240 test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) { 241 spin_lock_irqsave(&conn->c_lock, flags); 242 if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) 243 list_move(&rm->m_conn_item, &to_be_dropped); 244 spin_unlock_irqrestore(&conn->c_lock, flags); 245 rds_message_put(rm); 246 continue; 247 } 248 249 /* Require an ACK every once in a while */ 250 len = ntohl(rm->m_inc.i_hdr.h_len); 251 if (conn->c_unacked_packets == 0 || 252 conn->c_unacked_bytes < len) { 253 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags); 254 255 conn->c_unacked_packets = rds_sysctl_max_unacked_packets; 256 conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes; 257 rds_stats_inc(s_send_ack_required); 258 } else { 259 conn->c_unacked_bytes -= len; 260 conn->c_unacked_packets--; 261 } 262 263 conn->c_xmit_rm = rm; 264 } 265 266 /* 267 * Try and send an rdma message. Let's see if we can 268 * keep this simple and require that the transport either 269 * send the whole rdma or none of it. 270 */ 271 if (rm->m_rdma_op && !conn->c_xmit_rdma_sent) { 272 ret = conn->c_trans->xmit_rdma(conn, rm->m_rdma_op); 273 if (ret) 274 break; 275 conn->c_xmit_rdma_sent = 1; 276 /* The transport owns the mapped memory for now. 277 * You can't unmap it while it's on the send queue */ 278 set_bit(RDS_MSG_MAPPED, &rm->m_flags); 279 } 280 281 if (conn->c_xmit_hdr_off < sizeof(struct rds_header) || 282 conn->c_xmit_sg < rm->m_nents) { 283 ret = conn->c_trans->xmit(conn, rm, 284 conn->c_xmit_hdr_off, 285 conn->c_xmit_sg, 286 conn->c_xmit_data_off); 287 if (ret <= 0) 288 break; 289 290 if (conn->c_xmit_hdr_off < sizeof(struct rds_header)) { 291 tmp = min_t(int, ret, 292 sizeof(struct rds_header) - 293 conn->c_xmit_hdr_off); 294 conn->c_xmit_hdr_off += tmp; 295 ret -= tmp; 296 } 297 298 sg = &rm->m_sg[conn->c_xmit_sg]; 299 while (ret) { 300 tmp = min_t(int, ret, sg->length - 301 conn->c_xmit_data_off); 302 conn->c_xmit_data_off += tmp; 303 ret -= tmp; 304 if (conn->c_xmit_data_off == sg->length) { 305 conn->c_xmit_data_off = 0; 306 sg++; 307 conn->c_xmit_sg++; 308 BUG_ON(ret != 0 && 309 conn->c_xmit_sg == rm->m_nents); 310 } 311 } 312 } 313 } 314 315 /* Nuke any messages we decided not to retransmit. */ 316 if (!list_empty(&to_be_dropped)) 317 rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED); 318 319 if (conn->c_trans->xmit_complete) 320 conn->c_trans->xmit_complete(conn); 321 322 /* 323 * We might be racing with another sender who queued a message but 324 * backed off on noticing that we held the c_send_lock. If we check 325 * for queued messages after dropping the sem then either we'll 326 * see the queued message or the queuer will get the sem. If we 327 * notice the queued message then we trigger an immediate retry. 328 * 329 * We need to be careful only to do this when we stopped processing 330 * the send queue because it was empty. It's the only way we 331 * stop processing the loop when the transport hasn't taken 332 * responsibility for forward progress. 333 */ 334 mutex_unlock(&conn->c_send_lock); 335 336 if (conn->c_map_bytes || (send_quota == 0 && !was_empty)) { 337 /* We exhausted the send quota, but there's work left to 338 * do. Return and (re-)schedule the send worker. 339 */ 340 ret = -EAGAIN; 341 } 342 343 if (ret == 0 && was_empty) { 344 /* A simple bit test would be way faster than taking the 345 * spin lock */ 346 spin_lock_irqsave(&conn->c_lock, flags); 347 if (!list_empty(&conn->c_send_queue)) { 348 rds_stats_inc(s_send_sem_queue_raced); 349 ret = -EAGAIN; 350 } 351 spin_unlock_irqrestore(&conn->c_lock, flags); 352 } 353out: 354 return ret; 355} 356 357static void rds_send_sndbuf_remove(struct rds_sock *rs, struct rds_message *rm) 358{ 359 u32 len = be32_to_cpu(rm->m_inc.i_hdr.h_len); 360 361 assert_spin_locked(&rs->rs_lock); 362 363 BUG_ON(rs->rs_snd_bytes < len); 364 rs->rs_snd_bytes -= len; 365 366 if (rs->rs_snd_bytes == 0) 367 rds_stats_inc(s_send_queue_empty); 368} 369 370static inline int rds_send_is_acked(struct rds_message *rm, u64 ack, 371 is_acked_func is_acked) 372{ 373 if (is_acked) 374 return is_acked(rm, ack); 375 return be64_to_cpu(rm->m_inc.i_hdr.h_sequence) <= ack; 376} 377 378/* 379 * Returns true if there are no messages on the send and retransmit queues 380 * which have a sequence number greater than or equal to the given sequence 381 * number. 382 */ 383int rds_send_acked_before(struct rds_connection *conn, u64 seq) 384{ 385 struct rds_message *rm, *tmp; 386 int ret = 1; 387 388 spin_lock(&conn->c_lock); 389 390 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) { 391 if (be64_to_cpu(rm->m_inc.i_hdr.h_sequence) < seq) 392 ret = 0; 393 break; 394 } 395 396 list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) { 397 if (be64_to_cpu(rm->m_inc.i_hdr.h_sequence) < seq) 398 ret = 0; 399 break; 400 } 401 402 spin_unlock(&conn->c_lock); 403 404 return ret; 405} 406 407/* 408 * This is pretty similar to what happens below in the ACK 409 * handling code - except that we call here as soon as we get 410 * the IB send completion on the RDMA op and the accompanying 411 * message. 412 */ 413void rds_rdma_send_complete(struct rds_message *rm, int status) 414{ 415 struct rds_sock *rs = NULL; 416 struct rds_rdma_op *ro; 417 struct rds_notifier *notifier; 418 unsigned long flags; 419 420 spin_lock_irqsave(&rm->m_rs_lock, flags); 421 422 ro = rm->m_rdma_op; 423 if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) && 424 ro && ro->r_notify && ro->r_notifier) { 425 notifier = ro->r_notifier; 426 rs = rm->m_rs; 427 sock_hold(rds_rs_to_sk(rs)); 428 429 notifier->n_status = status; 430 spin_lock(&rs->rs_lock); 431 list_add_tail(¬ifier->n_list, &rs->rs_notify_queue); 432 spin_unlock(&rs->rs_lock); 433 434 ro->r_notifier = NULL; 435 } 436 437 spin_unlock_irqrestore(&rm->m_rs_lock, flags); 438 439 if (rs) { 440 rds_wake_sk_sleep(rs); 441 sock_put(rds_rs_to_sk(rs)); 442 } 443} 444EXPORT_SYMBOL_GPL(rds_rdma_send_complete); 445 446/* 447 * This is the same as rds_rdma_send_complete except we 448 * don't do any locking - we have all the ingredients (message, 449 * socket, socket lock) and can just move the notifier. 450 */ 451static inline void 452__rds_rdma_send_complete(struct rds_sock *rs, struct rds_message *rm, int status) 453{ 454 struct rds_rdma_op *ro; 455 456 ro = rm->m_rdma_op; 457 if (ro && ro->r_notify && ro->r_notifier) { 458 ro->r_notifier->n_status = status; 459 list_add_tail(&ro->r_notifier->n_list, &rs->rs_notify_queue); 460 ro->r_notifier = NULL; 461 } 462 463 /* No need to wake the app - caller does this */ 464} 465 466/* 467 * This is called from the IB send completion when we detect 468 * a RDMA operation that failed with remote access error. 469 * So speed is not an issue here. 470 */ 471struct rds_message *rds_send_get_message(struct rds_connection *conn, 472 struct rds_rdma_op *op) 473{ 474 struct rds_message *rm, *tmp, *found = NULL; 475 unsigned long flags; 476 477 spin_lock_irqsave(&conn->c_lock, flags); 478 479 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) { 480 if (rm->m_rdma_op == op) { 481 atomic_inc(&rm->m_refcount); 482 found = rm; 483 goto out; 484 } 485 } 486 487 list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) { 488 if (rm->m_rdma_op == op) { 489 atomic_inc(&rm->m_refcount); 490 found = rm; 491 break; 492 } 493 } 494 495out: 496 spin_unlock_irqrestore(&conn->c_lock, flags); 497 498 return found; 499} 500EXPORT_SYMBOL_GPL(rds_send_get_message); 501 502/* 503 * This removes messages from the socket's list if they're on it. The list 504 * argument must be private to the caller, we must be able to modify it 505 * without locks. The messages must have a reference held for their 506 * position on the list. This function will drop that reference after 507 * removing the messages from the 'messages' list regardless of if it found 508 * the messages on the socket list or not. 509 */ 510void rds_send_remove_from_sock(struct list_head *messages, int status) 511{ 512 unsigned long flags; 513 struct rds_sock *rs = NULL; 514 struct rds_message *rm; 515 516 while (!list_empty(messages)) { 517 int was_on_sock = 0; 518 519 rm = list_entry(messages->next, struct rds_message, 520 m_conn_item); 521 list_del_init(&rm->m_conn_item); 522 523 /* 524 * If we see this flag cleared then we're *sure* that someone 525 * else beat us to removing it from the sock. If we race 526 * with their flag update we'll get the lock and then really 527 * see that the flag has been cleared. 528 * 529 * The message spinlock makes sure nobody clears rm->m_rs 530 * while we're messing with it. It does not prevent the 531 * message from being removed from the socket, though. 532 */ 533 spin_lock_irqsave(&rm->m_rs_lock, flags); 534 if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) 535 goto unlock_and_drop; 536 537 if (rs != rm->m_rs) { 538 if (rs) { 539 rds_wake_sk_sleep(rs); 540 sock_put(rds_rs_to_sk(rs)); 541 } 542 rs = rm->m_rs; 543 sock_hold(rds_rs_to_sk(rs)); 544 } 545 spin_lock(&rs->rs_lock); 546 547 if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) { 548 struct rds_rdma_op *ro = rm->m_rdma_op; 549 struct rds_notifier *notifier; 550 551 list_del_init(&rm->m_sock_item); 552 rds_send_sndbuf_remove(rs, rm); 553 554 if (ro && ro->r_notifier && (status || ro->r_notify)) { 555 notifier = ro->r_notifier; 556 list_add_tail(¬ifier->n_list, 557 &rs->rs_notify_queue); 558 if (!notifier->n_status) 559 notifier->n_status = status; 560 rm->m_rdma_op->r_notifier = NULL; 561 } 562 was_on_sock = 1; 563 rm->m_rs = NULL; 564 } 565 spin_unlock(&rs->rs_lock); 566 567unlock_and_drop: 568 spin_unlock_irqrestore(&rm->m_rs_lock, flags); 569 rds_message_put(rm); 570 if (was_on_sock) 571 rds_message_put(rm); 572 } 573 574 if (rs) { 575 rds_wake_sk_sleep(rs); 576 sock_put(rds_rs_to_sk(rs)); 577 } 578} 579 580/* 581 * Transports call here when they've determined that the receiver queued 582 * messages up to, and including, the given sequence number. Messages are 583 * moved to the retrans queue when rds_send_xmit picks them off the send 584 * queue. This means that in the TCP case, the message may not have been 585 * assigned the m_ack_seq yet - but that's fine as long as tcp_is_acked 586 * checks the RDS_MSG_HAS_ACK_SEQ bit. 587 * 588 * XXX It's not clear to me how this is safely serialized with socket 589 * destruction. Maybe it should bail if it sees SOCK_DEAD. 590 */ 591void rds_send_drop_acked(struct rds_connection *conn, u64 ack, 592 is_acked_func is_acked) 593{ 594 struct rds_message *rm, *tmp; 595 unsigned long flags; 596 LIST_HEAD(list); 597 598 spin_lock_irqsave(&conn->c_lock, flags); 599 600 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) { 601 if (!rds_send_is_acked(rm, ack, is_acked)) 602 break; 603 604 list_move(&rm->m_conn_item, &list); 605 clear_bit(RDS_MSG_ON_CONN, &rm->m_flags); 606 } 607 608 /* order flag updates with spin locks */ 609 if (!list_empty(&list)) 610 smp_mb__after_clear_bit(); 611 612 spin_unlock_irqrestore(&conn->c_lock, flags); 613 614 /* now remove the messages from the sock list as needed */ 615 rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS); 616} 617EXPORT_SYMBOL_GPL(rds_send_drop_acked); 618 619void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest) 620{ 621 struct rds_message *rm, *tmp; 622 struct rds_connection *conn; 623 unsigned long flags; 624 LIST_HEAD(list); 625 626 /* get all the messages we're dropping under the rs lock */ 627 spin_lock_irqsave(&rs->rs_lock, flags); 628 629 list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) { 630 if (dest && (dest->sin_addr.s_addr != rm->m_daddr || 631 dest->sin_port != rm->m_inc.i_hdr.h_dport)) 632 continue; 633 634 list_move(&rm->m_sock_item, &list); 635 rds_send_sndbuf_remove(rs, rm); 636 clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags); 637 } 638 639 /* order flag updates with the rs lock */ 640 smp_mb__after_clear_bit(); 641 642 spin_unlock_irqrestore(&rs->rs_lock, flags); 643 644 if (list_empty(&list)) 645 return; 646 647 /* Remove the messages from the conn */ 648 list_for_each_entry(rm, &list, m_sock_item) { 649 650 conn = rm->m_inc.i_conn; 651 652 spin_lock_irqsave(&conn->c_lock, flags); 653 /* 654 * Maybe someone else beat us to removing rm from the conn. 655 * If we race with their flag update we'll get the lock and 656 * then really see that the flag has been cleared. 657 */ 658 if (!test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) { 659 spin_unlock_irqrestore(&conn->c_lock, flags); 660 continue; 661 } 662 list_del_init(&rm->m_conn_item); 663 spin_unlock_irqrestore(&conn->c_lock, flags); 664 665 /* 666 * Couldn't grab m_rs_lock in top loop (lock ordering), 667 * but we can now. 668 */ 669 spin_lock_irqsave(&rm->m_rs_lock, flags); 670 671 spin_lock(&rs->rs_lock); 672 __rds_rdma_send_complete(rs, rm, RDS_RDMA_CANCELED); 673 spin_unlock(&rs->rs_lock); 674 675 rm->m_rs = NULL; 676 spin_unlock_irqrestore(&rm->m_rs_lock, flags); 677 678 rds_message_put(rm); 679 } 680 681 rds_wake_sk_sleep(rs); 682 683 while (!list_empty(&list)) { 684 rm = list_entry(list.next, struct rds_message, m_sock_item); 685 list_del_init(&rm->m_sock_item); 686 687 rds_message_wait(rm); 688 rds_message_put(rm); 689 } 690} 691 692/* 693 * we only want this to fire once so we use the callers 'queued'. It's 694 * possible that another thread can race with us and remove the 695 * message from the flow with RDS_CANCEL_SENT_TO. 696 */ 697static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn, 698 struct rds_message *rm, __be16 sport, 699 __be16 dport, int *queued) 700{ 701 unsigned long flags; 702 u32 len; 703 704 if (*queued) 705 goto out; 706 707 len = be32_to_cpu(rm->m_inc.i_hdr.h_len); 708 709 /* this is the only place which holds both the socket's rs_lock 710 * and the connection's c_lock */ 711 spin_lock_irqsave(&rs->rs_lock, flags); 712 713 /* 714 * If there is a little space in sndbuf, we don't queue anything, 715 * and userspace gets -EAGAIN. But poll() indicates there's send 716 * room. This can lead to bad behavior (spinning) if snd_bytes isn't 717 * freed up by incoming acks. So we check the *old* value of 718 * rs_snd_bytes here to allow the last msg to exceed the buffer, 719 * and poll() now knows no more data can be sent. 720 */ 721 if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) { 722 rs->rs_snd_bytes += len; 723 724 /* let recv side know we are close to send space exhaustion. 725 * This is probably not the optimal way to do it, as this 726 * means we set the flag on *all* messages as soon as our 727 * throughput hits a certain threshold. 728 */ 729 if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2) 730 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags); 731 732 list_add_tail(&rm->m_sock_item, &rs->rs_send_queue); 733 set_bit(RDS_MSG_ON_SOCK, &rm->m_flags); 734 rds_message_addref(rm); 735 rm->m_rs = rs; 736 737 /* The code ordering is a little weird, but we're 738 trying to minimize the time we hold c_lock */ 739 rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0); 740 rm->m_inc.i_conn = conn; 741 rds_message_addref(rm); 742 743 spin_lock(&conn->c_lock); 744 rm->m_inc.i_hdr.h_sequence = cpu_to_be64(conn->c_next_tx_seq++); 745 list_add_tail(&rm->m_conn_item, &conn->c_send_queue); 746 set_bit(RDS_MSG_ON_CONN, &rm->m_flags); 747 spin_unlock(&conn->c_lock); 748 749 rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n", 750 rm, len, rs, rs->rs_snd_bytes, 751 (unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence)); 752 753 *queued = 1; 754 } 755 756 spin_unlock_irqrestore(&rs->rs_lock, flags); 757out: 758 return *queued; 759} 760 761static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm, 762 struct msghdr *msg, int *allocated_mr) 763{ 764 struct cmsghdr *cmsg; 765 int ret = 0; 766 767 for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) { 768 if (!CMSG_OK(msg, cmsg)) 769 return -EINVAL; 770 771 if (cmsg->cmsg_level != SOL_RDS) 772 continue; 773 774 /* As a side effect, RDMA_DEST and RDMA_MAP will set 775 * rm->m_rdma_cookie and rm->m_rdma_mr. 776 */ 777 switch (cmsg->cmsg_type) { 778 case RDS_CMSG_RDMA_ARGS: 779 ret = rds_cmsg_rdma_args(rs, rm, cmsg); 780 break; 781 782 case RDS_CMSG_RDMA_DEST: 783 ret = rds_cmsg_rdma_dest(rs, rm, cmsg); 784 break; 785 786 case RDS_CMSG_RDMA_MAP: 787 ret = rds_cmsg_rdma_map(rs, rm, cmsg); 788 if (!ret) 789 *allocated_mr = 1; 790 break; 791 792 default: 793 return -EINVAL; 794 } 795 796 if (ret) 797 break; 798 } 799 800 return ret; 801} 802 803int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg, 804 size_t payload_len) 805{ 806 struct sock *sk = sock->sk; 807 struct rds_sock *rs = rds_sk_to_rs(sk); 808 struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name; 809 __be32 daddr; 810 __be16 dport; 811 struct rds_message *rm = NULL; 812 struct rds_connection *conn; 813 int ret = 0; 814 int queued = 0, allocated_mr = 0; 815 int nonblock = msg->msg_flags & MSG_DONTWAIT; 816 long timeo = sock_sndtimeo(sk, nonblock); 817 818 /* Mirror Linux UDP mirror of BSD error message compatibility */ 819 /* XXX: Perhaps MSG_MORE someday */ 820 if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) { 821 printk(KERN_INFO "msg_flags 0x%08X\n", msg->msg_flags); 822 ret = -EOPNOTSUPP; 823 goto out; 824 } 825 826 if (msg->msg_namelen) { 827 /* XXX fail non-unicast destination IPs? */ 828 if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) { 829 ret = -EINVAL; 830 goto out; 831 } 832 daddr = usin->sin_addr.s_addr; 833 dport = usin->sin_port; 834 } else { 835 /* We only care about consistency with ->connect() */ 836 lock_sock(sk); 837 daddr = rs->rs_conn_addr; 838 dport = rs->rs_conn_port; 839 release_sock(sk); 840 } 841 842 /* racing with another thread binding seems ok here */ 843 if (daddr == 0 || rs->rs_bound_addr == 0) { 844 ret = -ENOTCONN; /* XXX not a great errno */ 845 goto out; 846 } 847 848 rm = rds_message_copy_from_user(msg->msg_iov, payload_len); 849 if (IS_ERR(rm)) { 850 ret = PTR_ERR(rm); 851 rm = NULL; 852 goto out; 853 } 854 855 rm->m_daddr = daddr; 856 857 /* rds_conn_create has a spinlock that runs with IRQ off. 858 * Caching the conn in the socket helps a lot. */ 859 if (rs->rs_conn && rs->rs_conn->c_faddr == daddr) 860 conn = rs->rs_conn; 861 else { 862 conn = rds_conn_create_outgoing(rs->rs_bound_addr, daddr, 863 rs->rs_transport, 864 sock->sk->sk_allocation); 865 if (IS_ERR(conn)) { 866 ret = PTR_ERR(conn); 867 goto out; 868 } 869 rs->rs_conn = conn; 870 } 871 872 /* Parse any control messages the user may have included. */ 873 ret = rds_cmsg_send(rs, rm, msg, &allocated_mr); 874 if (ret) 875 goto out; 876 877 if ((rm->m_rdma_cookie || rm->m_rdma_op) && 878 conn->c_trans->xmit_rdma == NULL) { 879 if (printk_ratelimit()) 880 printk(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n", 881 rm->m_rdma_op, conn->c_trans->xmit_rdma); 882 ret = -EOPNOTSUPP; 883 goto out; 884 } 885 886 /* If the connection is down, trigger a connect. We may 887 * have scheduled a delayed reconnect however - in this case 888 * we should not interfere. 889 */ 890 if (rds_conn_state(conn) == RDS_CONN_DOWN && 891 !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags)) 892 queue_delayed_work(rds_wq, &conn->c_conn_w, 0); 893 894 ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs); 895 if (ret) { 896 rs->rs_seen_congestion = 1; 897 goto out; 898 } 899 900 while (!rds_send_queue_rm(rs, conn, rm, rs->rs_bound_port, 901 dport, &queued)) { 902 rds_stats_inc(s_send_queue_full); 903 /* XXX make sure this is reasonable */ 904 if (payload_len > rds_sk_sndbuf(rs)) { 905 ret = -EMSGSIZE; 906 goto out; 907 } 908 if (nonblock) { 909 ret = -EAGAIN; 910 goto out; 911 } 912 913 timeo = wait_event_interruptible_timeout(*sk_sleep(sk), 914 rds_send_queue_rm(rs, conn, rm, 915 rs->rs_bound_port, 916 dport, 917 &queued), 918 timeo); 919 rdsdebug("sendmsg woke queued %d timeo %ld\n", queued, timeo); 920 if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT) 921 continue; 922 923 ret = timeo; 924 if (ret == 0) 925 ret = -ETIMEDOUT; 926 goto out; 927 } 928 929 /* 930 * By now we've committed to the send. We reuse rds_send_worker() 931 * to retry sends in the rds thread if the transport asks us to. 932 */ 933 rds_stats_inc(s_send_queued); 934 935 if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags)) 936 rds_send_worker(&conn->c_send_w.work); 937 938 rds_message_put(rm); 939 return payload_len; 940 941out: 942 /* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly. 943 * If the sendmsg goes through, we keep the MR. If it fails with EAGAIN 944 * or in any other way, we need to destroy the MR again */ 945 if (allocated_mr) 946 rds_rdma_unuse(rs, rds_rdma_cookie_key(rm->m_rdma_cookie), 1); 947 948 if (rm) 949 rds_message_put(rm); 950 return ret; 951} 952 953/* 954 * Reply to a ping packet. 955 */ 956int 957rds_send_pong(struct rds_connection *conn, __be16 dport) 958{ 959 struct rds_message *rm; 960 unsigned long flags; 961 int ret = 0; 962 963 rm = rds_message_alloc(0, GFP_ATOMIC); 964 if (rm == NULL) { 965 ret = -ENOMEM; 966 goto out; 967 } 968 969 rm->m_daddr = conn->c_faddr; 970 971 /* If the connection is down, trigger a connect. We may 972 * have scheduled a delayed reconnect however - in this case 973 * we should not interfere. 974 */ 975 if (rds_conn_state(conn) == RDS_CONN_DOWN && 976 !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags)) 977 queue_delayed_work(rds_wq, &conn->c_conn_w, 0); 978 979 ret = rds_cong_wait(conn->c_fcong, dport, 1, NULL); 980 if (ret) 981 goto out; 982 983 spin_lock_irqsave(&conn->c_lock, flags); 984 list_add_tail(&rm->m_conn_item, &conn->c_send_queue); 985 set_bit(RDS_MSG_ON_CONN, &rm->m_flags); 986 rds_message_addref(rm); 987 rm->m_inc.i_conn = conn; 988 989 rds_message_populate_header(&rm->m_inc.i_hdr, 0, dport, 990 conn->c_next_tx_seq); 991 conn->c_next_tx_seq++; 992 spin_unlock_irqrestore(&conn->c_lock, flags); 993 994 rds_stats_inc(s_send_queued); 995 rds_stats_inc(s_send_pong); 996 997 queue_delayed_work(rds_wq, &conn->c_send_w, 0); 998 rds_message_put(rm); 999 return 0; 1000 1001out: 1002 if (rm) 1003 rds_message_put(rm); 1004 return ret; 1005} 1006