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; 418 419 spin_lock(&rm->m_rs_lock); 420 421 ro = rm->m_rdma_op; 422 if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) && 423 ro && ro->r_notify && ro->r_notifier) { 424 notifier = ro->r_notifier; 425 rs = rm->m_rs; 426 sock_hold(rds_rs_to_sk(rs)); 427 428 notifier->n_status = status; 429 spin_lock(&rs->rs_lock); 430 list_add_tail(¬ifier->n_list, &rs->rs_notify_queue); 431 spin_unlock(&rs->rs_lock); 432 433 ro->r_notifier = NULL; 434 } 435 436 spin_unlock(&rm->m_rs_lock); 437 438 if (rs) { 439 rds_wake_sk_sleep(rs); 440 sock_put(rds_rs_to_sk(rs)); 441 } 442} 443EXPORT_SYMBOL_GPL(rds_rdma_send_complete); 444 445/* 446 * This is the same as rds_rdma_send_complete except we 447 * don't do any locking - we have all the ingredients (message, 448 * socket, socket lock) and can just move the notifier. 449 */ 450static inline void 451__rds_rdma_send_complete(struct rds_sock *rs, struct rds_message *rm, int status) 452{ 453 struct rds_rdma_op *ro; 454 455 ro = rm->m_rdma_op; 456 if (ro && ro->r_notify && ro->r_notifier) { 457 ro->r_notifier->n_status = status; 458 list_add_tail(&ro->r_notifier->n_list, &rs->rs_notify_queue); 459 ro->r_notifier = NULL; 460 } 461 462 /* No need to wake the app - caller does this */ 463} 464 465/* 466 * This is called from the IB send completion when we detect 467 * a RDMA operation that failed with remote access error. 468 * So speed is not an issue here. 469 */ 470struct rds_message *rds_send_get_message(struct rds_connection *conn, 471 struct rds_rdma_op *op) 472{ 473 struct rds_message *rm, *tmp, *found = NULL; 474 unsigned long flags; 475 476 spin_lock_irqsave(&conn->c_lock, flags); 477 478 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) { 479 if (rm->m_rdma_op == op) { 480 atomic_inc(&rm->m_refcount); 481 found = rm; 482 goto out; 483 } 484 } 485 486 list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) { 487 if (rm->m_rdma_op == op) { 488 atomic_inc(&rm->m_refcount); 489 found = rm; 490 break; 491 } 492 } 493 494out: 495 spin_unlock_irqrestore(&conn->c_lock, flags); 496 497 return found; 498} 499EXPORT_SYMBOL_GPL(rds_send_get_message); 500 501/* 502 * This removes messages from the socket's list if they're on it. The list 503 * argument must be private to the caller, we must be able to modify it 504 * without locks. The messages must have a reference held for their 505 * position on the list. This function will drop that reference after 506 * removing the messages from the 'messages' list regardless of if it found 507 * the messages on the socket list or not. 508 */ 509void rds_send_remove_from_sock(struct list_head *messages, int status) 510{ 511 unsigned long flags; 512 struct rds_sock *rs = NULL; 513 struct rds_message *rm; 514 515 while (!list_empty(messages)) { 516 int was_on_sock = 0; 517 518 rm = list_entry(messages->next, struct rds_message, 519 m_conn_item); 520 list_del_init(&rm->m_conn_item); 521 522 /* 523 * If we see this flag cleared then we're *sure* that someone 524 * else beat us to removing it from the sock. If we race 525 * with their flag update we'll get the lock and then really 526 * see that the flag has been cleared. 527 * 528 * The message spinlock makes sure nobody clears rm->m_rs 529 * while we're messing with it. It does not prevent the 530 * message from being removed from the socket, though. 531 */ 532 spin_lock_irqsave(&rm->m_rs_lock, flags); 533 if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) 534 goto unlock_and_drop; 535 536 if (rs != rm->m_rs) { 537 if (rs) { 538 rds_wake_sk_sleep(rs); 539 sock_put(rds_rs_to_sk(rs)); 540 } 541 rs = rm->m_rs; 542 sock_hold(rds_rs_to_sk(rs)); 543 } 544 spin_lock(&rs->rs_lock); 545 546 if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) { 547 struct rds_rdma_op *ro = rm->m_rdma_op; 548 struct rds_notifier *notifier; 549 550 list_del_init(&rm->m_sock_item); 551 rds_send_sndbuf_remove(rs, rm); 552 553 if (ro && ro->r_notifier && (status || ro->r_notify)) { 554 notifier = ro->r_notifier; 555 list_add_tail(¬ifier->n_list, 556 &rs->rs_notify_queue); 557 if (!notifier->n_status) 558 notifier->n_status = status; 559 rm->m_rdma_op->r_notifier = NULL; 560 } 561 was_on_sock = 1; 562 rm->m_rs = NULL; 563 } 564 spin_unlock(&rs->rs_lock); 565 566unlock_and_drop: 567 spin_unlock_irqrestore(&rm->m_rs_lock, flags); 568 rds_message_put(rm); 569 if (was_on_sock) 570 rds_message_put(rm); 571 } 572 573 if (rs) { 574 rds_wake_sk_sleep(rs); 575 sock_put(rds_rs_to_sk(rs)); 576 } 577} 578 579void rds_send_drop_acked(struct rds_connection *conn, u64 ack, 580 is_acked_func is_acked) 581{ 582 struct rds_message *rm, *tmp; 583 unsigned long flags; 584 LIST_HEAD(list); 585 586 spin_lock_irqsave(&conn->c_lock, flags); 587 588 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) { 589 if (!rds_send_is_acked(rm, ack, is_acked)) 590 break; 591 592 list_move(&rm->m_conn_item, &list); 593 clear_bit(RDS_MSG_ON_CONN, &rm->m_flags); 594 } 595 596 /* order flag updates with spin locks */ 597 if (!list_empty(&list)) 598 smp_mb__after_clear_bit(); 599 600 spin_unlock_irqrestore(&conn->c_lock, flags); 601 602 /* now remove the messages from the sock list as needed */ 603 rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS); 604} 605EXPORT_SYMBOL_GPL(rds_send_drop_acked); 606 607void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest) 608{ 609 struct rds_message *rm, *tmp; 610 struct rds_connection *conn; 611 unsigned long flags, flags2; 612 LIST_HEAD(list); 613 int wake = 0; 614 615 /* get all the messages we're dropping under the rs lock */ 616 spin_lock_irqsave(&rs->rs_lock, flags); 617 618 list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) { 619 if (dest && (dest->sin_addr.s_addr != rm->m_daddr || 620 dest->sin_port != rm->m_inc.i_hdr.h_dport)) 621 continue; 622 623 wake = 1; 624 list_move(&rm->m_sock_item, &list); 625 rds_send_sndbuf_remove(rs, rm); 626 clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags); 627 } 628 629 /* order flag updates with the rs lock */ 630 if (wake) 631 smp_mb__after_clear_bit(); 632 633 spin_unlock_irqrestore(&rs->rs_lock, flags); 634 635 conn = NULL; 636 637 /* now remove the messages from the conn list as needed */ 638 list_for_each_entry(rm, &list, m_sock_item) { 639 /* We do this here rather than in the loop above, so that 640 * we don't have to nest m_rs_lock under rs->rs_lock */ 641 spin_lock_irqsave(&rm->m_rs_lock, flags2); 642 /* If this is a RDMA operation, notify the app. */ 643 spin_lock(&rs->rs_lock); 644 __rds_rdma_send_complete(rs, rm, RDS_RDMA_CANCELED); 645 spin_unlock(&rs->rs_lock); 646 rm->m_rs = NULL; 647 spin_unlock_irqrestore(&rm->m_rs_lock, flags2); 648 649 /* 650 * If we see this flag cleared then we're *sure* that someone 651 * else beat us to removing it from the conn. If we race 652 * with their flag update we'll get the lock and then really 653 * see that the flag has been cleared. 654 */ 655 if (!test_bit(RDS_MSG_ON_CONN, &rm->m_flags)) 656 continue; 657 658 if (conn != rm->m_inc.i_conn) { 659 if (conn) 660 spin_unlock_irqrestore(&conn->c_lock, flags); 661 conn = rm->m_inc.i_conn; 662 spin_lock_irqsave(&conn->c_lock, flags); 663 } 664 665 if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) { 666 list_del_init(&rm->m_conn_item); 667 rds_message_put(rm); 668 } 669 } 670 671 if (conn) 672 spin_unlock_irqrestore(&conn->c_lock, flags); 673 674 if (wake) 675 rds_wake_sk_sleep(rs); 676 677 while (!list_empty(&list)) { 678 rm = list_entry(list.next, struct rds_message, m_sock_item); 679 list_del_init(&rm->m_sock_item); 680 681 rds_message_wait(rm); 682 rds_message_put(rm); 683 } 684} 685 686/* 687 * we only want this to fire once so we use the callers 'queued'. It's 688 * possible that another thread can race with us and remove the 689 * message from the flow with RDS_CANCEL_SENT_TO. 690 */ 691static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn, 692 struct rds_message *rm, __be16 sport, 693 __be16 dport, int *queued) 694{ 695 unsigned long flags; 696 u32 len; 697 698 if (*queued) 699 goto out; 700 701 len = be32_to_cpu(rm->m_inc.i_hdr.h_len); 702 703 /* this is the only place which holds both the socket's rs_lock 704 * and the connection's c_lock */ 705 spin_lock_irqsave(&rs->rs_lock, flags); 706 707 /* 708 * If there is a little space in sndbuf, we don't queue anything, 709 * and userspace gets -EAGAIN. But poll() indicates there's send 710 * room. This can lead to bad behavior (spinning) if snd_bytes isn't 711 * freed up by incoming acks. So we check the *old* value of 712 * rs_snd_bytes here to allow the last msg to exceed the buffer, 713 * and poll() now knows no more data can be sent. 714 */ 715 if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) { 716 rs->rs_snd_bytes += len; 717 718 /* let recv side know we are close to send space exhaustion. 719 * This is probably not the optimal way to do it, as this 720 * means we set the flag on *all* messages as soon as our 721 * throughput hits a certain threshold. 722 */ 723 if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2) 724 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags); 725 726 list_add_tail(&rm->m_sock_item, &rs->rs_send_queue); 727 set_bit(RDS_MSG_ON_SOCK, &rm->m_flags); 728 rds_message_addref(rm); 729 rm->m_rs = rs; 730 731 /* The code ordering is a little weird, but we're 732 trying to minimize the time we hold c_lock */ 733 rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0); 734 rm->m_inc.i_conn = conn; 735 rds_message_addref(rm); 736 737 spin_lock(&conn->c_lock); 738 rm->m_inc.i_hdr.h_sequence = cpu_to_be64(conn->c_next_tx_seq++); 739 list_add_tail(&rm->m_conn_item, &conn->c_send_queue); 740 set_bit(RDS_MSG_ON_CONN, &rm->m_flags); 741 spin_unlock(&conn->c_lock); 742 743 rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n", 744 rm, len, rs, rs->rs_snd_bytes, 745 (unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence)); 746 747 *queued = 1; 748 } 749 750 spin_unlock_irqrestore(&rs->rs_lock, flags); 751out: 752 return *queued; 753} 754 755static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm, 756 struct msghdr *msg, int *allocated_mr) 757{ 758 struct cmsghdr *cmsg; 759 int ret = 0; 760 761 for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) { 762 if (!CMSG_OK(msg, cmsg)) 763 return -EINVAL; 764 765 if (cmsg->cmsg_level != SOL_RDS) 766 continue; 767 768 /* As a side effect, RDMA_DEST and RDMA_MAP will set 769 * rm->m_rdma_cookie and rm->m_rdma_mr. 770 */ 771 switch (cmsg->cmsg_type) { 772 case RDS_CMSG_RDMA_ARGS: 773 ret = rds_cmsg_rdma_args(rs, rm, cmsg); 774 break; 775 776 case RDS_CMSG_RDMA_DEST: 777 ret = rds_cmsg_rdma_dest(rs, rm, cmsg); 778 break; 779 780 case RDS_CMSG_RDMA_MAP: 781 ret = rds_cmsg_rdma_map(rs, rm, cmsg); 782 if (!ret) 783 *allocated_mr = 1; 784 break; 785 786 default: 787 return -EINVAL; 788 } 789 790 if (ret) 791 break; 792 } 793 794 return ret; 795} 796 797int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg, 798 size_t payload_len) 799{ 800 struct sock *sk = sock->sk; 801 struct rds_sock *rs = rds_sk_to_rs(sk); 802 struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name; 803 __be32 daddr; 804 __be16 dport; 805 struct rds_message *rm = NULL; 806 struct rds_connection *conn; 807 int ret = 0; 808 int queued = 0, allocated_mr = 0; 809 int nonblock = msg->msg_flags & MSG_DONTWAIT; 810 long timeo = sock_sndtimeo(sk, nonblock); 811 812 /* Mirror Linux UDP mirror of BSD error message compatibility */ 813 if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) { 814 printk(KERN_INFO "msg_flags 0x%08X\n", msg->msg_flags); 815 ret = -EOPNOTSUPP; 816 goto out; 817 } 818 819 if (msg->msg_namelen) { 820 if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) { 821 ret = -EINVAL; 822 goto out; 823 } 824 daddr = usin->sin_addr.s_addr; 825 dport = usin->sin_port; 826 } else { 827 /* We only care about consistency with ->connect() */ 828 lock_sock(sk); 829 daddr = rs->rs_conn_addr; 830 dport = rs->rs_conn_port; 831 release_sock(sk); 832 } 833 834 /* racing with another thread binding seems ok here */ 835 if (daddr == 0 || rs->rs_bound_addr == 0) { 836 ret = -ENOTCONN; 837 goto out; 838 } 839 840 rm = rds_message_copy_from_user(msg->msg_iov, payload_len); 841 if (IS_ERR(rm)) { 842 ret = PTR_ERR(rm); 843 rm = NULL; 844 goto out; 845 } 846 847 rm->m_daddr = daddr; 848 849 /* rds_conn_create has a spinlock that runs with IRQ off. 850 * Caching the conn in the socket helps a lot. */ 851 if (rs->rs_conn && rs->rs_conn->c_faddr == daddr) 852 conn = rs->rs_conn; 853 else { 854 conn = rds_conn_create_outgoing(rs->rs_bound_addr, daddr, 855 rs->rs_transport, 856 sock->sk->sk_allocation); 857 if (IS_ERR(conn)) { 858 ret = PTR_ERR(conn); 859 goto out; 860 } 861 rs->rs_conn = conn; 862 } 863 864 /* Parse any control messages the user may have included. */ 865 ret = rds_cmsg_send(rs, rm, msg, &allocated_mr); 866 if (ret) 867 goto out; 868 869 if ((rm->m_rdma_cookie || rm->m_rdma_op) && 870 conn->c_trans->xmit_rdma == NULL) { 871 if (printk_ratelimit()) 872 printk(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n", 873 rm->m_rdma_op, conn->c_trans->xmit_rdma); 874 ret = -EOPNOTSUPP; 875 goto out; 876 } 877 878 /* If the connection is down, trigger a connect. We may 879 * have scheduled a delayed reconnect however - in this case 880 * we should not interfere. 881 */ 882 if (rds_conn_state(conn) == RDS_CONN_DOWN && 883 !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags)) 884 queue_delayed_work(rds_wq, &conn->c_conn_w, 0); 885 886 ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs); 887 if (ret) { 888 rs->rs_seen_congestion = 1; 889 goto out; 890 } 891 892 while (!rds_send_queue_rm(rs, conn, rm, rs->rs_bound_port, 893 dport, &queued)) { 894 rds_stats_inc(s_send_queue_full); 895 if (payload_len > rds_sk_sndbuf(rs)) { 896 ret = -EMSGSIZE; 897 goto out; 898 } 899 if (nonblock) { 900 ret = -EAGAIN; 901 goto out; 902 } 903 904 timeo = wait_event_interruptible_timeout(*sk_sleep(sk), 905 rds_send_queue_rm(rs, conn, rm, 906 rs->rs_bound_port, 907 dport, 908 &queued), 909 timeo); 910 rdsdebug("sendmsg woke queued %d timeo %ld\n", queued, timeo); 911 if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT) 912 continue; 913 914 ret = timeo; 915 if (ret == 0) 916 ret = -ETIMEDOUT; 917 goto out; 918 } 919 920 /* 921 * By now we've committed to the send. We reuse rds_send_worker() 922 * to retry sends in the rds thread if the transport asks us to. 923 */ 924 rds_stats_inc(s_send_queued); 925 926 if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags)) 927 rds_send_worker(&conn->c_send_w.work); 928 929 rds_message_put(rm); 930 return payload_len; 931 932out: 933 /* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly. 934 * If the sendmsg goes through, we keep the MR. If it fails with EAGAIN 935 * or in any other way, we need to destroy the MR again */ 936 if (allocated_mr) 937 rds_rdma_unuse(rs, rds_rdma_cookie_key(rm->m_rdma_cookie), 1); 938 939 if (rm) 940 rds_message_put(rm); 941 return ret; 942} 943 944/* 945 * Reply to a ping packet. 946 */ 947int 948rds_send_pong(struct rds_connection *conn, __be16 dport) 949{ 950 struct rds_message *rm; 951 unsigned long flags; 952 int ret = 0; 953 954 rm = rds_message_alloc(0, GFP_ATOMIC); 955 if (rm == NULL) { 956 ret = -ENOMEM; 957 goto out; 958 } 959 960 rm->m_daddr = conn->c_faddr; 961 962 /* If the connection is down, trigger a connect. We may 963 * have scheduled a delayed reconnect however - in this case 964 * we should not interfere. 965 */ 966 if (rds_conn_state(conn) == RDS_CONN_DOWN && 967 !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags)) 968 queue_delayed_work(rds_wq, &conn->c_conn_w, 0); 969 970 ret = rds_cong_wait(conn->c_fcong, dport, 1, NULL); 971 if (ret) 972 goto out; 973 974 spin_lock_irqsave(&conn->c_lock, flags); 975 list_add_tail(&rm->m_conn_item, &conn->c_send_queue); 976 set_bit(RDS_MSG_ON_CONN, &rm->m_flags); 977 rds_message_addref(rm); 978 rm->m_inc.i_conn = conn; 979 980 rds_message_populate_header(&rm->m_inc.i_hdr, 0, dport, 981 conn->c_next_tx_seq); 982 conn->c_next_tx_seq++; 983 spin_unlock_irqrestore(&conn->c_lock, flags); 984 985 rds_stats_inc(s_send_queued); 986 rds_stats_inc(s_send_pong); 987 988 queue_delayed_work(rds_wq, &conn->c_send_w, 0); 989 rds_message_put(rm); 990 return 0; 991 992out: 993 if (rm) 994 rds_message_put(rm); 995 return ret; 996} 997