send.c revision 6c7cc6e4694dc464ae884332f2a322973497e3cf
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 41/* When transmitting messages in rds_send_xmit, we need to emerge from 42 * time to time and briefly release the CPU. Otherwise the softlock watchdog 43 * will kick our shin. 44 * Also, it seems fairer to not let one busy connection stall all the 45 * others. 46 * 47 * send_batch_count is the number of times we'll loop in send_xmit. Setting 48 * it to 0 will restore the old behavior (where we looped until we had 49 * drained the queue). 50 */ 51static int send_batch_count = 64; 52module_param(send_batch_count, int, 0444); 53MODULE_PARM_DESC(send_batch_count, " batch factor when working the send queue"); 54 55/* 56 * Reset the send state. Caller must hold c_send_lock when calling here. 57 */ 58void rds_send_reset(struct rds_connection *conn) 59{ 60 struct rds_message *rm, *tmp; 61 unsigned long flags; 62 63 if (conn->c_xmit_rm) { 64 /* Tell the user the RDMA op is no longer mapped by the 65 * transport. This isn't entirely true (it's flushed out 66 * independently) but as the connection is down, there's 67 * no ongoing RDMA to/from that memory */ 68 rds_message_unmapped(conn->c_xmit_rm); 69 rds_message_put(conn->c_xmit_rm); 70 conn->c_xmit_rm = NULL; 71 } 72 conn->c_xmit_sg = 0; 73 conn->c_xmit_hdr_off = 0; 74 conn->c_xmit_data_off = 0; 75 conn->c_xmit_rdma_sent = 0; 76 conn->c_xmit_atomic_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 && 168 conn->c_xmit_hdr_off == sizeof(struct rds_header) && 169 conn->c_xmit_sg == rm->data.op_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 conn->c_xmit_atomic_sent = 0; 176 177 /* Release the reference to the previous message. */ 178 rds_message_put(rm); 179 rm = NULL; 180 } 181 182 /* If we're asked to send a cong map update, do so. 183 */ 184 if (!rm && test_and_clear_bit(0, &conn->c_map_queued)) { 185 if (conn->c_trans->xmit_cong_map) { 186 conn->c_map_offset = 0; 187 conn->c_map_bytes = sizeof(struct rds_header) + 188 RDS_CONG_MAP_BYTES; 189 continue; 190 } 191 192 rm = rds_cong_update_alloc(conn); 193 if (IS_ERR(rm)) { 194 ret = PTR_ERR(rm); 195 break; 196 } 197 198 conn->c_xmit_rm = rm; 199 } 200 201 /* 202 * Grab the next message from the send queue, if there is one. 203 * 204 * c_xmit_rm holds a ref while we're sending this message down 205 * the connction. We can use this ref while holding the 206 * send_sem.. rds_send_reset() is serialized with it. 207 */ 208 if (!rm) { 209 unsigned int len; 210 211 spin_lock_irqsave(&conn->c_lock, flags); 212 213 if (!list_empty(&conn->c_send_queue)) { 214 rm = list_entry(conn->c_send_queue.next, 215 struct rds_message, 216 m_conn_item); 217 rds_message_addref(rm); 218 219 /* 220 * Move the message from the send queue to the retransmit 221 * list right away. 222 */ 223 list_move_tail(&rm->m_conn_item, &conn->c_retrans); 224 } 225 226 spin_unlock_irqrestore(&conn->c_lock, flags); 227 228 if (!rm) { 229 was_empty = 1; 230 break; 231 } 232 233 /* Unfortunately, the way Infiniband deals with 234 * RDMA to a bad MR key is by moving the entire 235 * queue pair to error state. We cold possibly 236 * recover from that, but right now we drop the 237 * connection. 238 * Therefore, we never retransmit messages with RDMA ops. 239 */ 240 if (rm->rdma.op_active && 241 test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) { 242 spin_lock_irqsave(&conn->c_lock, flags); 243 if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) 244 list_move(&rm->m_conn_item, &to_be_dropped); 245 spin_unlock_irqrestore(&conn->c_lock, flags); 246 rds_message_put(rm); 247 continue; 248 } 249 250 /* Require an ACK every once in a while */ 251 len = ntohl(rm->m_inc.i_hdr.h_len); 252 if (conn->c_unacked_packets == 0 || 253 conn->c_unacked_bytes < len) { 254 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags); 255 256 conn->c_unacked_packets = rds_sysctl_max_unacked_packets; 257 conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes; 258 rds_stats_inc(s_send_ack_required); 259 } else { 260 conn->c_unacked_bytes -= len; 261 conn->c_unacked_packets--; 262 } 263 264 conn->c_xmit_rm = rm; 265 } 266 267 268 if (rm->atomic.op_active && !conn->c_xmit_atomic_sent) { 269 ret = conn->c_trans->xmit_atomic(conn, rm); 270 if (ret) 271 break; 272 conn->c_xmit_atomic_sent = 1; 273 /* The transport owns the mapped memory for now. 274 * You can't unmap it while it's on the send queue */ 275 set_bit(RDS_MSG_MAPPED, &rm->m_flags); 276 } 277 278 /* 279 * Try and send an rdma message. Let's see if we can 280 * keep this simple and require that the transport either 281 * send the whole rdma or none of it. 282 */ 283 if (rm->rdma.op_active && !conn->c_xmit_rdma_sent) { 284 ret = conn->c_trans->xmit_rdma(conn, &rm->rdma); 285 if (ret) 286 break; 287 conn->c_xmit_rdma_sent = 1; 288 289 /* rdmas need data sent, even if just the header */ 290 rm->data.op_active = 1; 291 292 /* The transport owns the mapped memory for now. 293 * You can't unmap it while it's on the send queue */ 294 set_bit(RDS_MSG_MAPPED, &rm->m_flags); 295 } 296 297 if (rm->data.op_active 298 && (conn->c_xmit_hdr_off < sizeof(struct rds_header) || 299 conn->c_xmit_sg < rm->data.op_nents)) { 300 ret = conn->c_trans->xmit(conn, rm, 301 conn->c_xmit_hdr_off, 302 conn->c_xmit_sg, 303 conn->c_xmit_data_off); 304 if (ret <= 0) 305 break; 306 307 if (conn->c_xmit_hdr_off < sizeof(struct rds_header)) { 308 tmp = min_t(int, ret, 309 sizeof(struct rds_header) - 310 conn->c_xmit_hdr_off); 311 conn->c_xmit_hdr_off += tmp; 312 ret -= tmp; 313 } 314 315 sg = &rm->data.op_sg[conn->c_xmit_sg]; 316 while (ret) { 317 tmp = min_t(int, ret, sg->length - 318 conn->c_xmit_data_off); 319 conn->c_xmit_data_off += tmp; 320 ret -= tmp; 321 if (conn->c_xmit_data_off == sg->length) { 322 conn->c_xmit_data_off = 0; 323 sg++; 324 conn->c_xmit_sg++; 325 BUG_ON(ret != 0 && 326 conn->c_xmit_sg == rm->data.op_nents); 327 } 328 } 329 } 330 } 331 332 /* Nuke any messages we decided not to retransmit. */ 333 if (!list_empty(&to_be_dropped)) 334 rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED); 335 336 if (conn->c_trans->xmit_complete) 337 conn->c_trans->xmit_complete(conn); 338 339 /* 340 * We might be racing with another sender who queued a message but 341 * backed off on noticing that we held the c_send_lock. If we check 342 * for queued messages after dropping the sem then either we'll 343 * see the queued message or the queuer will get the sem. If we 344 * notice the queued message then we trigger an immediate retry. 345 * 346 * We need to be careful only to do this when we stopped processing 347 * the send queue because it was empty. It's the only way we 348 * stop processing the loop when the transport hasn't taken 349 * responsibility for forward progress. 350 */ 351 mutex_unlock(&conn->c_send_lock); 352 353 if (conn->c_map_bytes || (send_quota == 0 && !was_empty)) { 354 /* We exhausted the send quota, but there's work left to 355 * do. Return and (re-)schedule the send worker. 356 */ 357 ret = -EAGAIN; 358 } 359 360 if (ret == 0 && was_empty) { 361 /* A simple bit test would be way faster than taking the 362 * spin lock */ 363 spin_lock_irqsave(&conn->c_lock, flags); 364 if (!list_empty(&conn->c_send_queue)) { 365 rds_stats_inc(s_send_sem_queue_raced); 366 ret = -EAGAIN; 367 } 368 spin_unlock_irqrestore(&conn->c_lock, flags); 369 } 370out: 371 return ret; 372} 373 374static void rds_send_sndbuf_remove(struct rds_sock *rs, struct rds_message *rm) 375{ 376 u32 len = be32_to_cpu(rm->m_inc.i_hdr.h_len); 377 378 assert_spin_locked(&rs->rs_lock); 379 380 BUG_ON(rs->rs_snd_bytes < len); 381 rs->rs_snd_bytes -= len; 382 383 if (rs->rs_snd_bytes == 0) 384 rds_stats_inc(s_send_queue_empty); 385} 386 387static inline int rds_send_is_acked(struct rds_message *rm, u64 ack, 388 is_acked_func is_acked) 389{ 390 if (is_acked) 391 return is_acked(rm, ack); 392 return be64_to_cpu(rm->m_inc.i_hdr.h_sequence) <= ack; 393} 394 395/* 396 * Returns true if there are no messages on the send and retransmit queues 397 * which have a sequence number greater than or equal to the given sequence 398 * number. 399 */ 400int rds_send_acked_before(struct rds_connection *conn, u64 seq) 401{ 402 struct rds_message *rm, *tmp; 403 int ret = 1; 404 405 spin_lock(&conn->c_lock); 406 407 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) { 408 if (be64_to_cpu(rm->m_inc.i_hdr.h_sequence) < seq) 409 ret = 0; 410 break; 411 } 412 413 list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) { 414 if (be64_to_cpu(rm->m_inc.i_hdr.h_sequence) < seq) 415 ret = 0; 416 break; 417 } 418 419 spin_unlock(&conn->c_lock); 420 421 return ret; 422} 423 424/* 425 * This is pretty similar to what happens below in the ACK 426 * handling code - except that we call here as soon as we get 427 * the IB send completion on the RDMA op and the accompanying 428 * message. 429 */ 430void rds_rdma_send_complete(struct rds_message *rm, int status) 431{ 432 struct rds_sock *rs = NULL; 433 struct rm_rdma_op *ro; 434 struct rds_notifier *notifier; 435 unsigned long flags; 436 437 spin_lock_irqsave(&rm->m_rs_lock, flags); 438 439 ro = &rm->rdma; 440 if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) && 441 ro->op_active && ro->op_notify && ro->op_notifier) { 442 notifier = ro->op_notifier; 443 rs = rm->m_rs; 444 sock_hold(rds_rs_to_sk(rs)); 445 446 notifier->n_status = status; 447 spin_lock(&rs->rs_lock); 448 list_add_tail(¬ifier->n_list, &rs->rs_notify_queue); 449 spin_unlock(&rs->rs_lock); 450 451 ro->op_notifier = NULL; 452 } 453 454 spin_unlock_irqrestore(&rm->m_rs_lock, flags); 455 456 if (rs) { 457 rds_wake_sk_sleep(rs); 458 sock_put(rds_rs_to_sk(rs)); 459 } 460} 461EXPORT_SYMBOL_GPL(rds_rdma_send_complete); 462 463/* 464 * Just like above, except looks at atomic op 465 */ 466void rds_atomic_send_complete(struct rds_message *rm, int status) 467{ 468 struct rds_sock *rs = NULL; 469 struct rm_atomic_op *ao; 470 struct rds_notifier *notifier; 471 472 spin_lock(&rm->m_rs_lock); 473 474 ao = &rm->atomic; 475 if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) 476 && ao->op_active && ao->op_notify && ao->op_notifier) { 477 notifier = ao->op_notifier; 478 rs = rm->m_rs; 479 sock_hold(rds_rs_to_sk(rs)); 480 481 notifier->n_status = status; 482 spin_lock(&rs->rs_lock); 483 list_add_tail(¬ifier->n_list, &rs->rs_notify_queue); 484 spin_unlock(&rs->rs_lock); 485 486 ao->op_notifier = NULL; 487 } 488 489 spin_unlock(&rm->m_rs_lock); 490 491 if (rs) { 492 rds_wake_sk_sleep(rs); 493 sock_put(rds_rs_to_sk(rs)); 494 } 495} 496EXPORT_SYMBOL_GPL(rds_atomic_send_complete); 497 498/* 499 * This is the same as rds_rdma_send_complete except we 500 * don't do any locking - we have all the ingredients (message, 501 * socket, socket lock) and can just move the notifier. 502 */ 503static inline void 504__rds_rdma_send_complete(struct rds_sock *rs, struct rds_message *rm, int status) 505{ 506 struct rm_rdma_op *ro; 507 508 ro = &rm->rdma; 509 if (ro->op_active && ro->op_notify && ro->op_notifier) { 510 ro->op_notifier->n_status = status; 511 list_add_tail(&ro->op_notifier->n_list, &rs->rs_notify_queue); 512 ro->op_notifier = NULL; 513 } 514 515 /* No need to wake the app - caller does this */ 516} 517 518/* 519 * This is called from the IB send completion when we detect 520 * a RDMA operation that failed with remote access error. 521 * So speed is not an issue here. 522 */ 523struct rds_message *rds_send_get_message(struct rds_connection *conn, 524 struct rm_rdma_op *op) 525{ 526 struct rds_message *rm, *tmp, *found = NULL; 527 unsigned long flags; 528 529 spin_lock_irqsave(&conn->c_lock, flags); 530 531 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) { 532 if (&rm->rdma == op) { 533 atomic_inc(&rm->m_refcount); 534 found = rm; 535 goto out; 536 } 537 } 538 539 list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) { 540 if (&rm->rdma == op) { 541 atomic_inc(&rm->m_refcount); 542 found = rm; 543 break; 544 } 545 } 546 547out: 548 spin_unlock_irqrestore(&conn->c_lock, flags); 549 550 return found; 551} 552EXPORT_SYMBOL_GPL(rds_send_get_message); 553 554/* 555 * This removes messages from the socket's list if they're on it. The list 556 * argument must be private to the caller, we must be able to modify it 557 * without locks. The messages must have a reference held for their 558 * position on the list. This function will drop that reference after 559 * removing the messages from the 'messages' list regardless of if it found 560 * the messages on the socket list or not. 561 */ 562void rds_send_remove_from_sock(struct list_head *messages, int status) 563{ 564 unsigned long flags; 565 struct rds_sock *rs = NULL; 566 struct rds_message *rm; 567 568 while (!list_empty(messages)) { 569 int was_on_sock = 0; 570 571 rm = list_entry(messages->next, struct rds_message, 572 m_conn_item); 573 list_del_init(&rm->m_conn_item); 574 575 /* 576 * If we see this flag cleared then we're *sure* that someone 577 * else beat us to removing it from the sock. If we race 578 * with their flag update we'll get the lock and then really 579 * see that the flag has been cleared. 580 * 581 * The message spinlock makes sure nobody clears rm->m_rs 582 * while we're messing with it. It does not prevent the 583 * message from being removed from the socket, though. 584 */ 585 spin_lock_irqsave(&rm->m_rs_lock, flags); 586 if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) 587 goto unlock_and_drop; 588 589 if (rs != rm->m_rs) { 590 if (rs) { 591 rds_wake_sk_sleep(rs); 592 sock_put(rds_rs_to_sk(rs)); 593 } 594 rs = rm->m_rs; 595 sock_hold(rds_rs_to_sk(rs)); 596 } 597 spin_lock(&rs->rs_lock); 598 599 if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) { 600 struct rm_rdma_op *ro = &rm->rdma; 601 struct rds_notifier *notifier; 602 603 list_del_init(&rm->m_sock_item); 604 rds_send_sndbuf_remove(rs, rm); 605 606 if (ro->op_active && ro->op_notifier && 607 (ro->op_notify || (ro->op_recverr && status))) { 608 notifier = ro->op_notifier; 609 list_add_tail(¬ifier->n_list, 610 &rs->rs_notify_queue); 611 if (!notifier->n_status) 612 notifier->n_status = status; 613 rm->rdma.op_notifier = NULL; 614 } 615 was_on_sock = 1; 616 rm->m_rs = NULL; 617 } 618 spin_unlock(&rs->rs_lock); 619 620unlock_and_drop: 621 spin_unlock_irqrestore(&rm->m_rs_lock, flags); 622 rds_message_put(rm); 623 if (was_on_sock) 624 rds_message_put(rm); 625 } 626 627 if (rs) { 628 rds_wake_sk_sleep(rs); 629 sock_put(rds_rs_to_sk(rs)); 630 } 631} 632 633/* 634 * Transports call here when they've determined that the receiver queued 635 * messages up to, and including, the given sequence number. Messages are 636 * moved to the retrans queue when rds_send_xmit picks them off the send 637 * queue. This means that in the TCP case, the message may not have been 638 * assigned the m_ack_seq yet - but that's fine as long as tcp_is_acked 639 * checks the RDS_MSG_HAS_ACK_SEQ bit. 640 * 641 * XXX It's not clear to me how this is safely serialized with socket 642 * destruction. Maybe it should bail if it sees SOCK_DEAD. 643 */ 644void rds_send_drop_acked(struct rds_connection *conn, u64 ack, 645 is_acked_func is_acked) 646{ 647 struct rds_message *rm, *tmp; 648 unsigned long flags; 649 LIST_HEAD(list); 650 651 spin_lock_irqsave(&conn->c_lock, flags); 652 653 list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) { 654 if (!rds_send_is_acked(rm, ack, is_acked)) 655 break; 656 657 list_move(&rm->m_conn_item, &list); 658 clear_bit(RDS_MSG_ON_CONN, &rm->m_flags); 659 } 660 661 /* order flag updates with spin locks */ 662 if (!list_empty(&list)) 663 smp_mb__after_clear_bit(); 664 665 spin_unlock_irqrestore(&conn->c_lock, flags); 666 667 /* now remove the messages from the sock list as needed */ 668 rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS); 669} 670EXPORT_SYMBOL_GPL(rds_send_drop_acked); 671 672void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest) 673{ 674 struct rds_message *rm, *tmp; 675 struct rds_connection *conn; 676 unsigned long flags; 677 LIST_HEAD(list); 678 679 /* get all the messages we're dropping under the rs lock */ 680 spin_lock_irqsave(&rs->rs_lock, flags); 681 682 list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) { 683 if (dest && (dest->sin_addr.s_addr != rm->m_daddr || 684 dest->sin_port != rm->m_inc.i_hdr.h_dport)) 685 continue; 686 687 list_move(&rm->m_sock_item, &list); 688 rds_send_sndbuf_remove(rs, rm); 689 clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags); 690 } 691 692 /* order flag updates with the rs lock */ 693 smp_mb__after_clear_bit(); 694 695 spin_unlock_irqrestore(&rs->rs_lock, flags); 696 697 if (list_empty(&list)) 698 return; 699 700 /* Remove the messages from the conn */ 701 list_for_each_entry(rm, &list, m_sock_item) { 702 703 conn = rm->m_inc.i_conn; 704 705 spin_lock_irqsave(&conn->c_lock, flags); 706 /* 707 * Maybe someone else beat us to removing rm from the conn. 708 * If we race with their flag update we'll get the lock and 709 * then really see that the flag has been cleared. 710 */ 711 if (!test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) { 712 spin_unlock_irqrestore(&conn->c_lock, flags); 713 continue; 714 } 715 list_del_init(&rm->m_conn_item); 716 spin_unlock_irqrestore(&conn->c_lock, flags); 717 718 /* 719 * Couldn't grab m_rs_lock in top loop (lock ordering), 720 * but we can now. 721 */ 722 spin_lock_irqsave(&rm->m_rs_lock, flags); 723 724 spin_lock(&rs->rs_lock); 725 __rds_rdma_send_complete(rs, rm, RDS_RDMA_CANCELED); 726 spin_unlock(&rs->rs_lock); 727 728 rm->m_rs = NULL; 729 spin_unlock_irqrestore(&rm->m_rs_lock, flags); 730 731 rds_message_put(rm); 732 } 733 734 rds_wake_sk_sleep(rs); 735 736 while (!list_empty(&list)) { 737 rm = list_entry(list.next, struct rds_message, m_sock_item); 738 list_del_init(&rm->m_sock_item); 739 740 rds_message_wait(rm); 741 rds_message_put(rm); 742 } 743} 744 745/* 746 * we only want this to fire once so we use the callers 'queued'. It's 747 * possible that another thread can race with us and remove the 748 * message from the flow with RDS_CANCEL_SENT_TO. 749 */ 750static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn, 751 struct rds_message *rm, __be16 sport, 752 __be16 dport, int *queued) 753{ 754 unsigned long flags; 755 u32 len; 756 757 if (*queued) 758 goto out; 759 760 len = be32_to_cpu(rm->m_inc.i_hdr.h_len); 761 762 /* this is the only place which holds both the socket's rs_lock 763 * and the connection's c_lock */ 764 spin_lock_irqsave(&rs->rs_lock, flags); 765 766 /* 767 * If there is a little space in sndbuf, we don't queue anything, 768 * and userspace gets -EAGAIN. But poll() indicates there's send 769 * room. This can lead to bad behavior (spinning) if snd_bytes isn't 770 * freed up by incoming acks. So we check the *old* value of 771 * rs_snd_bytes here to allow the last msg to exceed the buffer, 772 * and poll() now knows no more data can be sent. 773 */ 774 if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) { 775 rs->rs_snd_bytes += len; 776 777 /* let recv side know we are close to send space exhaustion. 778 * This is probably not the optimal way to do it, as this 779 * means we set the flag on *all* messages as soon as our 780 * throughput hits a certain threshold. 781 */ 782 if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2) 783 __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags); 784 785 list_add_tail(&rm->m_sock_item, &rs->rs_send_queue); 786 set_bit(RDS_MSG_ON_SOCK, &rm->m_flags); 787 rds_message_addref(rm); 788 rm->m_rs = rs; 789 790 /* The code ordering is a little weird, but we're 791 trying to minimize the time we hold c_lock */ 792 rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0); 793 rm->m_inc.i_conn = conn; 794 rds_message_addref(rm); 795 796 spin_lock(&conn->c_lock); 797 rm->m_inc.i_hdr.h_sequence = cpu_to_be64(conn->c_next_tx_seq++); 798 list_add_tail(&rm->m_conn_item, &conn->c_send_queue); 799 set_bit(RDS_MSG_ON_CONN, &rm->m_flags); 800 spin_unlock(&conn->c_lock); 801 802 rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n", 803 rm, len, rs, rs->rs_snd_bytes, 804 (unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence)); 805 806 *queued = 1; 807 } 808 809 spin_unlock_irqrestore(&rs->rs_lock, flags); 810out: 811 return *queued; 812} 813 814/* 815 * rds_message is getting to be quite complicated, and we'd like to allocate 816 * it all in one go. This figures out how big it needs to be up front. 817 */ 818static int rds_rm_size(struct msghdr *msg, int data_len) 819{ 820 struct cmsghdr *cmsg; 821 int size = 0; 822 int retval; 823 824 for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) { 825 if (!CMSG_OK(msg, cmsg)) 826 return -EINVAL; 827 828 if (cmsg->cmsg_level != SOL_RDS) 829 continue; 830 831 switch (cmsg->cmsg_type) { 832 case RDS_CMSG_RDMA_ARGS: 833 retval = rds_rdma_extra_size(CMSG_DATA(cmsg)); 834 if (retval < 0) 835 return retval; 836 size += retval; 837 break; 838 839 case RDS_CMSG_RDMA_DEST: 840 case RDS_CMSG_RDMA_MAP: 841 /* these are valid but do no add any size */ 842 break; 843 844 case RDS_CMSG_ATOMIC_CSWP: 845 case RDS_CMSG_ATOMIC_FADD: 846 size += sizeof(struct scatterlist); 847 break; 848 849 default: 850 return -EINVAL; 851 } 852 853 } 854 855 size += ceil(data_len, PAGE_SIZE) * sizeof(struct scatterlist); 856 857 return size; 858} 859 860static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm, 861 struct msghdr *msg, int *allocated_mr) 862{ 863 struct cmsghdr *cmsg; 864 int ret = 0; 865 866 for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) { 867 if (!CMSG_OK(msg, cmsg)) 868 return -EINVAL; 869 870 if (cmsg->cmsg_level != SOL_RDS) 871 continue; 872 873 /* As a side effect, RDMA_DEST and RDMA_MAP will set 874 * rm->rdma.m_rdma_cookie and rm->rdma.m_rdma_mr. 875 */ 876 switch (cmsg->cmsg_type) { 877 case RDS_CMSG_RDMA_ARGS: 878 ret = rds_cmsg_rdma_args(rs, rm, cmsg); 879 break; 880 881 case RDS_CMSG_RDMA_DEST: 882 ret = rds_cmsg_rdma_dest(rs, rm, cmsg); 883 break; 884 885 case RDS_CMSG_RDMA_MAP: 886 ret = rds_cmsg_rdma_map(rs, rm, cmsg); 887 if (!ret) 888 *allocated_mr = 1; 889 break; 890 case RDS_CMSG_ATOMIC_CSWP: 891 case RDS_CMSG_ATOMIC_FADD: 892 ret = rds_cmsg_atomic(rs, rm, cmsg); 893 break; 894 895 default: 896 return -EINVAL; 897 } 898 899 if (ret) 900 break; 901 } 902 903 return ret; 904} 905 906int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg, 907 size_t payload_len) 908{ 909 struct sock *sk = sock->sk; 910 struct rds_sock *rs = rds_sk_to_rs(sk); 911 struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name; 912 __be32 daddr; 913 __be16 dport; 914 struct rds_message *rm = NULL; 915 struct rds_connection *conn; 916 int ret = 0; 917 int queued = 0, allocated_mr = 0; 918 int nonblock = msg->msg_flags & MSG_DONTWAIT; 919 long timeo = sock_sndtimeo(sk, nonblock); 920 921 /* Mirror Linux UDP mirror of BSD error message compatibility */ 922 /* XXX: Perhaps MSG_MORE someday */ 923 if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) { 924 printk(KERN_INFO "msg_flags 0x%08X\n", msg->msg_flags); 925 ret = -EOPNOTSUPP; 926 goto out; 927 } 928 929 if (msg->msg_namelen) { 930 /* XXX fail non-unicast destination IPs? */ 931 if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) { 932 ret = -EINVAL; 933 goto out; 934 } 935 daddr = usin->sin_addr.s_addr; 936 dport = usin->sin_port; 937 } else { 938 /* We only care about consistency with ->connect() */ 939 lock_sock(sk); 940 daddr = rs->rs_conn_addr; 941 dport = rs->rs_conn_port; 942 release_sock(sk); 943 } 944 945 /* racing with another thread binding seems ok here */ 946 if (daddr == 0 || rs->rs_bound_addr == 0) { 947 ret = -ENOTCONN; /* XXX not a great errno */ 948 goto out; 949 } 950 951 /* size of rm including all sgs */ 952 ret = rds_rm_size(msg, payload_len); 953 if (ret < 0) 954 goto out; 955 956 rm = rds_message_alloc(ret, GFP_KERNEL); 957 if (!rm) { 958 ret = -ENOMEM; 959 goto out; 960 } 961 962 rm->data.op_sg = rds_message_alloc_sgs(rm, ceil(payload_len, PAGE_SIZE)); 963 /* XXX fix this to not allocate memory */ 964 ret = rds_message_copy_from_user(rm, msg->msg_iov, payload_len); 965 if (ret) 966 goto out; 967 968 rm->m_daddr = daddr; 969 970 /* rds_conn_create has a spinlock that runs with IRQ off. 971 * Caching the conn in the socket helps a lot. */ 972 if (rs->rs_conn && rs->rs_conn->c_faddr == daddr) 973 conn = rs->rs_conn; 974 else { 975 conn = rds_conn_create_outgoing(rs->rs_bound_addr, daddr, 976 rs->rs_transport, 977 sock->sk->sk_allocation); 978 if (IS_ERR(conn)) { 979 ret = PTR_ERR(conn); 980 goto out; 981 } 982 rs->rs_conn = conn; 983 } 984 985 /* Parse any control messages the user may have included. */ 986 ret = rds_cmsg_send(rs, rm, msg, &allocated_mr); 987 if (ret) 988 goto out; 989 990 if ((rm->m_rdma_cookie || rm->rdma.op_active) && 991 !conn->c_trans->xmit_rdma) { 992 if (printk_ratelimit()) 993 printk(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n", 994 &rm->rdma, conn->c_trans->xmit_rdma); 995 ret = -EOPNOTSUPP; 996 goto out; 997 } 998 999 if (rm->atomic.op_active && !conn->c_trans->xmit_atomic) { 1000 if (printk_ratelimit()) 1001 printk(KERN_NOTICE "atomic_op %p conn xmit_atomic %p\n", 1002 &rm->atomic, conn->c_trans->xmit_atomic); 1003 ret = -EOPNOTSUPP; 1004 goto out; 1005 } 1006 1007 /* If the connection is down, trigger a connect. We may 1008 * have scheduled a delayed reconnect however - in this case 1009 * we should not interfere. 1010 */ 1011 if (rds_conn_state(conn) == RDS_CONN_DOWN && 1012 !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags)) 1013 queue_delayed_work(rds_wq, &conn->c_conn_w, 0); 1014 1015 ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs); 1016 if (ret) { 1017 rs->rs_seen_congestion = 1; 1018 goto out; 1019 } 1020 1021 while (!rds_send_queue_rm(rs, conn, rm, rs->rs_bound_port, 1022 dport, &queued)) { 1023 rds_stats_inc(s_send_queue_full); 1024 /* XXX make sure this is reasonable */ 1025 if (payload_len > rds_sk_sndbuf(rs)) { 1026 ret = -EMSGSIZE; 1027 goto out; 1028 } 1029 if (nonblock) { 1030 ret = -EAGAIN; 1031 goto out; 1032 } 1033 1034 timeo = wait_event_interruptible_timeout(*sk_sleep(sk), 1035 rds_send_queue_rm(rs, conn, rm, 1036 rs->rs_bound_port, 1037 dport, 1038 &queued), 1039 timeo); 1040 rdsdebug("sendmsg woke queued %d timeo %ld\n", queued, timeo); 1041 if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT) 1042 continue; 1043 1044 ret = timeo; 1045 if (ret == 0) 1046 ret = -ETIMEDOUT; 1047 goto out; 1048 } 1049 1050 /* 1051 * By now we've committed to the send. We reuse rds_send_worker() 1052 * to retry sends in the rds thread if the transport asks us to. 1053 */ 1054 rds_stats_inc(s_send_queued); 1055 1056 if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags)) 1057 rds_send_worker(&conn->c_send_w.work); 1058 1059 rds_message_put(rm); 1060 return payload_len; 1061 1062out: 1063 /* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly. 1064 * If the sendmsg goes through, we keep the MR. If it fails with EAGAIN 1065 * or in any other way, we need to destroy the MR again */ 1066 if (allocated_mr) 1067 rds_rdma_unuse(rs, rds_rdma_cookie_key(rm->m_rdma_cookie), 1); 1068 1069 if (rm) 1070 rds_message_put(rm); 1071 return ret; 1072} 1073 1074/* 1075 * Reply to a ping packet. 1076 */ 1077int 1078rds_send_pong(struct rds_connection *conn, __be16 dport) 1079{ 1080 struct rds_message *rm; 1081 unsigned long flags; 1082 int ret = 0; 1083 1084 rm = rds_message_alloc(0, GFP_ATOMIC); 1085 if (!rm) { 1086 ret = -ENOMEM; 1087 goto out; 1088 } 1089 1090 rm->m_daddr = conn->c_faddr; 1091 1092 /* If the connection is down, trigger a connect. We may 1093 * have scheduled a delayed reconnect however - in this case 1094 * we should not interfere. 1095 */ 1096 if (rds_conn_state(conn) == RDS_CONN_DOWN && 1097 !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags)) 1098 queue_delayed_work(rds_wq, &conn->c_conn_w, 0); 1099 1100 ret = rds_cong_wait(conn->c_fcong, dport, 1, NULL); 1101 if (ret) 1102 goto out; 1103 1104 spin_lock_irqsave(&conn->c_lock, flags); 1105 list_add_tail(&rm->m_conn_item, &conn->c_send_queue); 1106 set_bit(RDS_MSG_ON_CONN, &rm->m_flags); 1107 rds_message_addref(rm); 1108 rm->m_inc.i_conn = conn; 1109 1110 rds_message_populate_header(&rm->m_inc.i_hdr, 0, dport, 1111 conn->c_next_tx_seq); 1112 conn->c_next_tx_seq++; 1113 spin_unlock_irqrestore(&conn->c_lock, flags); 1114 1115 rds_stats_inc(s_send_queued); 1116 rds_stats_inc(s_send_pong); 1117 1118 queue_delayed_work(rds_wq, &conn->c_send_w, 0); 1119 rds_message_put(rm); 1120 return 0; 1121 1122out: 1123 if (rm) 1124 rds_message_put(rm); 1125 return ret; 1126} 1127