xprt.c revision 1570c1e41eabf6b7031f3e4322a2cf1cbe319fee
1/* 2 * linux/net/sunrpc/xprt.c 3 * 4 * This is a generic RPC call interface supporting congestion avoidance, 5 * and asynchronous calls. 6 * 7 * The interface works like this: 8 * 9 * - When a process places a call, it allocates a request slot if 10 * one is available. Otherwise, it sleeps on the backlog queue 11 * (xprt_reserve). 12 * - Next, the caller puts together the RPC message, stuffs it into 13 * the request struct, and calls xprt_transmit(). 14 * - xprt_transmit sends the message and installs the caller on the 15 * transport's wait list. At the same time, it installs a timer that 16 * is run after the packet's timeout has expired. 17 * - When a packet arrives, the data_ready handler walks the list of 18 * pending requests for that transport. If a matching XID is found, the 19 * caller is woken up, and the timer removed. 20 * - When no reply arrives within the timeout interval, the timer is 21 * fired by the kernel and runs xprt_timer(). It either adjusts the 22 * timeout values (minor timeout) or wakes up the caller with a status 23 * of -ETIMEDOUT. 24 * - When the caller receives a notification from RPC that a reply arrived, 25 * it should release the RPC slot, and process the reply. 26 * If the call timed out, it may choose to retry the operation by 27 * adjusting the initial timeout value, and simply calling rpc_call 28 * again. 29 * 30 * Support for async RPC is done through a set of RPC-specific scheduling 31 * primitives that `transparently' work for processes as well as async 32 * tasks that rely on callbacks. 33 * 34 * Copyright (C) 1995-1997, Olaf Kirch <okir@monad.swb.de> 35 * 36 * Transport switch API copyright (C) 2005, Chuck Lever <cel@netapp.com> 37 */ 38 39#include <linux/module.h> 40 41#include <linux/types.h> 42#include <linux/interrupt.h> 43#include <linux/workqueue.h> 44#include <linux/random.h> 45 46#include <linux/sunrpc/clnt.h> 47 48/* 49 * Local variables 50 */ 51 52#ifdef RPC_DEBUG 53# undef RPC_DEBUG_DATA 54# define RPCDBG_FACILITY RPCDBG_XPRT 55#endif 56 57/* 58 * Local functions 59 */ 60static void xprt_request_init(struct rpc_task *, struct rpc_xprt *); 61static inline void do_xprt_reserve(struct rpc_task *); 62static void xprt_connect_status(struct rpc_task *task); 63static int __xprt_get_cong(struct rpc_xprt *, struct rpc_task *); 64 65static int xprt_clear_backlog(struct rpc_xprt *xprt); 66 67/** 68 * xprt_reserve_xprt - serialize write access to transports 69 * @task: task that is requesting access to the transport 70 * 71 * This prevents mixing the payload of separate requests, and prevents 72 * transport connects from colliding with writes. No congestion control 73 * is provided. 74 */ 75int xprt_reserve_xprt(struct rpc_task *task) 76{ 77 struct rpc_xprt *xprt = task->tk_xprt; 78 struct rpc_rqst *req = task->tk_rqstp; 79 80 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) { 81 if (task == xprt->snd_task) 82 return 1; 83 if (task == NULL) 84 return 0; 85 goto out_sleep; 86 } 87 xprt->snd_task = task; 88 if (req) { 89 req->rq_bytes_sent = 0; 90 req->rq_ntrans++; 91 } 92 return 1; 93 94out_sleep: 95 dprintk("RPC: %4d failed to lock transport %p\n", 96 task->tk_pid, xprt); 97 task->tk_timeout = 0; 98 task->tk_status = -EAGAIN; 99 if (req && req->rq_ntrans) 100 rpc_sleep_on(&xprt->resend, task, NULL, NULL); 101 else 102 rpc_sleep_on(&xprt->sending, task, NULL, NULL); 103 return 0; 104} 105 106/* 107 * xprt_reserve_xprt_cong - serialize write access to transports 108 * @task: task that is requesting access to the transport 109 * 110 * Same as xprt_reserve_xprt, but Van Jacobson congestion control is 111 * integrated into the decision of whether a request is allowed to be 112 * woken up and given access to the transport. 113 */ 114int xprt_reserve_xprt_cong(struct rpc_task *task) 115{ 116 struct rpc_xprt *xprt = task->tk_xprt; 117 struct rpc_rqst *req = task->tk_rqstp; 118 119 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) { 120 if (task == xprt->snd_task) 121 return 1; 122 goto out_sleep; 123 } 124 if (__xprt_get_cong(xprt, task)) { 125 xprt->snd_task = task; 126 if (req) { 127 req->rq_bytes_sent = 0; 128 req->rq_ntrans++; 129 } 130 return 1; 131 } 132 smp_mb__before_clear_bit(); 133 clear_bit(XPRT_LOCKED, &xprt->state); 134 smp_mb__after_clear_bit(); 135out_sleep: 136 dprintk("RPC: %4d failed to lock transport %p\n", task->tk_pid, xprt); 137 task->tk_timeout = 0; 138 task->tk_status = -EAGAIN; 139 if (req && req->rq_ntrans) 140 rpc_sleep_on(&xprt->resend, task, NULL, NULL); 141 else 142 rpc_sleep_on(&xprt->sending, task, NULL, NULL); 143 return 0; 144} 145 146static inline int xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task) 147{ 148 int retval; 149 150 spin_lock_bh(&xprt->transport_lock); 151 retval = xprt->ops->reserve_xprt(task); 152 spin_unlock_bh(&xprt->transport_lock); 153 return retval; 154} 155 156static void __xprt_lock_write_next(struct rpc_xprt *xprt) 157{ 158 struct rpc_task *task; 159 struct rpc_rqst *req; 160 161 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) 162 return; 163 164 task = rpc_wake_up_next(&xprt->resend); 165 if (!task) { 166 task = rpc_wake_up_next(&xprt->sending); 167 if (!task) 168 goto out_unlock; 169 } 170 171 req = task->tk_rqstp; 172 xprt->snd_task = task; 173 if (req) { 174 req->rq_bytes_sent = 0; 175 req->rq_ntrans++; 176 } 177 return; 178 179out_unlock: 180 smp_mb__before_clear_bit(); 181 clear_bit(XPRT_LOCKED, &xprt->state); 182 smp_mb__after_clear_bit(); 183} 184 185static void __xprt_lock_write_next_cong(struct rpc_xprt *xprt) 186{ 187 struct rpc_task *task; 188 189 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) 190 return; 191 if (RPCXPRT_CONGESTED(xprt)) 192 goto out_unlock; 193 task = rpc_wake_up_next(&xprt->resend); 194 if (!task) { 195 task = rpc_wake_up_next(&xprt->sending); 196 if (!task) 197 goto out_unlock; 198 } 199 if (__xprt_get_cong(xprt, task)) { 200 struct rpc_rqst *req = task->tk_rqstp; 201 xprt->snd_task = task; 202 if (req) { 203 req->rq_bytes_sent = 0; 204 req->rq_ntrans++; 205 } 206 return; 207 } 208out_unlock: 209 smp_mb__before_clear_bit(); 210 clear_bit(XPRT_LOCKED, &xprt->state); 211 smp_mb__after_clear_bit(); 212} 213 214/** 215 * xprt_release_xprt - allow other requests to use a transport 216 * @xprt: transport with other tasks potentially waiting 217 * @task: task that is releasing access to the transport 218 * 219 * Note that "task" can be NULL. No congestion control is provided. 220 */ 221void xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task) 222{ 223 if (xprt->snd_task == task) { 224 xprt->snd_task = NULL; 225 smp_mb__before_clear_bit(); 226 clear_bit(XPRT_LOCKED, &xprt->state); 227 smp_mb__after_clear_bit(); 228 __xprt_lock_write_next(xprt); 229 } 230} 231 232/** 233 * xprt_release_xprt_cong - allow other requests to use a transport 234 * @xprt: transport with other tasks potentially waiting 235 * @task: task that is releasing access to the transport 236 * 237 * Note that "task" can be NULL. Another task is awoken to use the 238 * transport if the transport's congestion window allows it. 239 */ 240void xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task) 241{ 242 if (xprt->snd_task == task) { 243 xprt->snd_task = NULL; 244 smp_mb__before_clear_bit(); 245 clear_bit(XPRT_LOCKED, &xprt->state); 246 smp_mb__after_clear_bit(); 247 __xprt_lock_write_next_cong(xprt); 248 } 249} 250 251static inline void xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task) 252{ 253 spin_lock_bh(&xprt->transport_lock); 254 xprt->ops->release_xprt(xprt, task); 255 spin_unlock_bh(&xprt->transport_lock); 256} 257 258/* 259 * Van Jacobson congestion avoidance. Check if the congestion window 260 * overflowed. Put the task to sleep if this is the case. 261 */ 262static int 263__xprt_get_cong(struct rpc_xprt *xprt, struct rpc_task *task) 264{ 265 struct rpc_rqst *req = task->tk_rqstp; 266 267 if (req->rq_cong) 268 return 1; 269 dprintk("RPC: %4d xprt_cwnd_limited cong = %ld cwnd = %ld\n", 270 task->tk_pid, xprt->cong, xprt->cwnd); 271 if (RPCXPRT_CONGESTED(xprt)) 272 return 0; 273 req->rq_cong = 1; 274 xprt->cong += RPC_CWNDSCALE; 275 return 1; 276} 277 278/* 279 * Adjust the congestion window, and wake up the next task 280 * that has been sleeping due to congestion 281 */ 282static void 283__xprt_put_cong(struct rpc_xprt *xprt, struct rpc_rqst *req) 284{ 285 if (!req->rq_cong) 286 return; 287 req->rq_cong = 0; 288 xprt->cong -= RPC_CWNDSCALE; 289 __xprt_lock_write_next_cong(xprt); 290} 291 292/** 293 * xprt_adjust_cwnd - adjust transport congestion window 294 * @task: recently completed RPC request used to adjust window 295 * @result: result code of completed RPC request 296 * 297 * We use a time-smoothed congestion estimator to avoid heavy oscillation. 298 */ 299void xprt_adjust_cwnd(struct rpc_task *task, int result) 300{ 301 struct rpc_rqst *req = task->tk_rqstp; 302 struct rpc_xprt *xprt = task->tk_xprt; 303 unsigned long cwnd = xprt->cwnd; 304 305 if (result >= 0 && cwnd <= xprt->cong) { 306 /* The (cwnd >> 1) term makes sure 307 * the result gets rounded properly. */ 308 cwnd += (RPC_CWNDSCALE * RPC_CWNDSCALE + (cwnd >> 1)) / cwnd; 309 if (cwnd > RPC_MAXCWND(xprt)) 310 cwnd = RPC_MAXCWND(xprt); 311 __xprt_lock_write_next_cong(xprt); 312 } else if (result == -ETIMEDOUT) { 313 cwnd >>= 1; 314 if (cwnd < RPC_CWNDSCALE) 315 cwnd = RPC_CWNDSCALE; 316 } 317 dprintk("RPC: cong %ld, cwnd was %ld, now %ld\n", 318 xprt->cong, xprt->cwnd, cwnd); 319 xprt->cwnd = cwnd; 320 __xprt_put_cong(xprt, req); 321} 322 323/** 324 * xprt_wake_pending_tasks - wake all tasks on a transport's pending queue 325 * @xprt: transport with waiting tasks 326 * @status: result code to plant in each task before waking it 327 * 328 */ 329void xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status) 330{ 331 if (status < 0) 332 rpc_wake_up_status(&xprt->pending, status); 333 else 334 rpc_wake_up(&xprt->pending); 335} 336 337/** 338 * xprt_wait_for_buffer_space - wait for transport output buffer to clear 339 * @task: task to be put to sleep 340 * 341 */ 342void xprt_wait_for_buffer_space(struct rpc_task *task) 343{ 344 struct rpc_rqst *req = task->tk_rqstp; 345 struct rpc_xprt *xprt = req->rq_xprt; 346 347 task->tk_timeout = req->rq_timeout; 348 rpc_sleep_on(&xprt->pending, task, NULL, NULL); 349} 350 351/** 352 * xprt_write_space - wake the task waiting for transport output buffer space 353 * @xprt: transport with waiting tasks 354 * 355 * Can be called in a soft IRQ context, so xprt_write_space never sleeps. 356 */ 357void xprt_write_space(struct rpc_xprt *xprt) 358{ 359 if (unlikely(xprt->shutdown)) 360 return; 361 362 spin_lock_bh(&xprt->transport_lock); 363 if (xprt->snd_task) { 364 dprintk("RPC: write space: waking waiting task on xprt %p\n", 365 xprt); 366 rpc_wake_up_task(xprt->snd_task); 367 } 368 spin_unlock_bh(&xprt->transport_lock); 369} 370 371/** 372 * xprt_set_retrans_timeout_def - set a request's retransmit timeout 373 * @task: task whose timeout is to be set 374 * 375 * Set a request's retransmit timeout based on the transport's 376 * default timeout parameters. Used by transports that don't adjust 377 * the retransmit timeout based on round-trip time estimation. 378 */ 379void xprt_set_retrans_timeout_def(struct rpc_task *task) 380{ 381 task->tk_timeout = task->tk_rqstp->rq_timeout; 382} 383 384/* 385 * xprt_set_retrans_timeout_rtt - set a request's retransmit timeout 386 * @task: task whose timeout is to be set 387 * 388 * Set a request's retransmit timeout using the RTT estimator. 389 */ 390void xprt_set_retrans_timeout_rtt(struct rpc_task *task) 391{ 392 int timer = task->tk_msg.rpc_proc->p_timer; 393 struct rpc_rtt *rtt = task->tk_client->cl_rtt; 394 struct rpc_rqst *req = task->tk_rqstp; 395 unsigned long max_timeout = req->rq_xprt->timeout.to_maxval; 396 397 task->tk_timeout = rpc_calc_rto(rtt, timer); 398 task->tk_timeout <<= rpc_ntimeo(rtt, timer) + req->rq_retries; 399 if (task->tk_timeout > max_timeout || task->tk_timeout == 0) 400 task->tk_timeout = max_timeout; 401} 402 403static void xprt_reset_majortimeo(struct rpc_rqst *req) 404{ 405 struct rpc_timeout *to = &req->rq_xprt->timeout; 406 407 req->rq_majortimeo = req->rq_timeout; 408 if (to->to_exponential) 409 req->rq_majortimeo <<= to->to_retries; 410 else 411 req->rq_majortimeo += to->to_increment * to->to_retries; 412 if (req->rq_majortimeo > to->to_maxval || req->rq_majortimeo == 0) 413 req->rq_majortimeo = to->to_maxval; 414 req->rq_majortimeo += jiffies; 415} 416 417/** 418 * xprt_adjust_timeout - adjust timeout values for next retransmit 419 * @req: RPC request containing parameters to use for the adjustment 420 * 421 */ 422int xprt_adjust_timeout(struct rpc_rqst *req) 423{ 424 struct rpc_xprt *xprt = req->rq_xprt; 425 struct rpc_timeout *to = &xprt->timeout; 426 int status = 0; 427 428 if (time_before(jiffies, req->rq_majortimeo)) { 429 if (to->to_exponential) 430 req->rq_timeout <<= 1; 431 else 432 req->rq_timeout += to->to_increment; 433 if (to->to_maxval && req->rq_timeout >= to->to_maxval) 434 req->rq_timeout = to->to_maxval; 435 req->rq_retries++; 436 pprintk("RPC: %lu retrans\n", jiffies); 437 } else { 438 req->rq_timeout = to->to_initval; 439 req->rq_retries = 0; 440 xprt_reset_majortimeo(req); 441 /* Reset the RTT counters == "slow start" */ 442 spin_lock_bh(&xprt->transport_lock); 443 rpc_init_rtt(req->rq_task->tk_client->cl_rtt, to->to_initval); 444 spin_unlock_bh(&xprt->transport_lock); 445 pprintk("RPC: %lu timeout\n", jiffies); 446 status = -ETIMEDOUT; 447 } 448 449 if (req->rq_timeout == 0) { 450 printk(KERN_WARNING "xprt_adjust_timeout: rq_timeout = 0!\n"); 451 req->rq_timeout = 5 * HZ; 452 } 453 return status; 454} 455 456static void xprt_autoclose(void *args) 457{ 458 struct rpc_xprt *xprt = (struct rpc_xprt *)args; 459 460 xprt_disconnect(xprt); 461 xprt->ops->close(xprt); 462 xprt_release_write(xprt, NULL); 463} 464 465/** 466 * xprt_disconnect - mark a transport as disconnected 467 * @xprt: transport to flag for disconnect 468 * 469 */ 470void xprt_disconnect(struct rpc_xprt *xprt) 471{ 472 dprintk("RPC: disconnected transport %p\n", xprt); 473 spin_lock_bh(&xprt->transport_lock); 474 xprt_clear_connected(xprt); 475 xprt_wake_pending_tasks(xprt, -ENOTCONN); 476 spin_unlock_bh(&xprt->transport_lock); 477} 478 479static void 480xprt_init_autodisconnect(unsigned long data) 481{ 482 struct rpc_xprt *xprt = (struct rpc_xprt *)data; 483 484 spin_lock(&xprt->transport_lock); 485 if (!list_empty(&xprt->recv) || xprt->shutdown) 486 goto out_abort; 487 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) 488 goto out_abort; 489 spin_unlock(&xprt->transport_lock); 490 if (xprt_connecting(xprt)) 491 xprt_release_write(xprt, NULL); 492 else 493 schedule_work(&xprt->task_cleanup); 494 return; 495out_abort: 496 spin_unlock(&xprt->transport_lock); 497} 498 499/** 500 * xprt_connect - schedule a transport connect operation 501 * @task: RPC task that is requesting the connect 502 * 503 */ 504void xprt_connect(struct rpc_task *task) 505{ 506 struct rpc_xprt *xprt = task->tk_xprt; 507 508 dprintk("RPC: %4d xprt_connect xprt %p %s connected\n", task->tk_pid, 509 xprt, (xprt_connected(xprt) ? "is" : "is not")); 510 511 if (xprt->shutdown) { 512 task->tk_status = -EIO; 513 return; 514 } 515 if (!xprt->addr.sin_port) { 516 task->tk_status = -EIO; 517 return; 518 } 519 if (!xprt_lock_write(xprt, task)) 520 return; 521 if (xprt_connected(xprt)) 522 xprt_release_write(xprt, task); 523 else { 524 if (task->tk_rqstp) 525 task->tk_rqstp->rq_bytes_sent = 0; 526 527 task->tk_timeout = RPC_CONNECT_TIMEOUT; 528 rpc_sleep_on(&xprt->pending, task, xprt_connect_status, NULL); 529 xprt->ops->connect(task); 530 } 531 return; 532} 533 534static void xprt_connect_status(struct rpc_task *task) 535{ 536 struct rpc_xprt *xprt = task->tk_xprt; 537 538 if (task->tk_status >= 0) { 539 dprintk("RPC: %4d xprt_connect_status: connection established\n", 540 task->tk_pid); 541 return; 542 } 543 544 switch (task->tk_status) { 545 case -ECONNREFUSED: 546 case -ECONNRESET: 547 dprintk("RPC: %4d xprt_connect_status: server %s refused connection\n", 548 task->tk_pid, task->tk_client->cl_server); 549 break; 550 case -ENOTCONN: 551 dprintk("RPC: %4d xprt_connect_status: connection broken\n", 552 task->tk_pid); 553 break; 554 case -ETIMEDOUT: 555 dprintk("RPC: %4d xprt_connect_status: connect attempt timed out\n", 556 task->tk_pid); 557 break; 558 default: 559 dprintk("RPC: %4d xprt_connect_status: error %d connecting to server %s\n", 560 task->tk_pid, -task->tk_status, task->tk_client->cl_server); 561 xprt_release_write(xprt, task); 562 task->tk_status = -EIO; 563 return; 564 } 565 566 /* if soft mounted, just cause this RPC to fail */ 567 if (RPC_IS_SOFT(task)) { 568 xprt_release_write(xprt, task); 569 task->tk_status = -EIO; 570 } 571} 572 573/** 574 * xprt_lookup_rqst - find an RPC request corresponding to an XID 575 * @xprt: transport on which the original request was transmitted 576 * @xid: RPC XID of incoming reply 577 * 578 */ 579struct rpc_rqst *xprt_lookup_rqst(struct rpc_xprt *xprt, u32 xid) 580{ 581 struct list_head *pos; 582 struct rpc_rqst *req = NULL; 583 584 list_for_each(pos, &xprt->recv) { 585 struct rpc_rqst *entry = list_entry(pos, struct rpc_rqst, rq_list); 586 if (entry->rq_xid == xid) { 587 req = entry; 588 break; 589 } 590 } 591 return req; 592} 593 594/** 595 * xprt_update_rtt - update an RPC client's RTT state after receiving a reply 596 * @task: RPC request that recently completed 597 * 598 */ 599void xprt_update_rtt(struct rpc_task *task) 600{ 601 struct rpc_rqst *req = task->tk_rqstp; 602 struct rpc_rtt *rtt = task->tk_client->cl_rtt; 603 unsigned timer = task->tk_msg.rpc_proc->p_timer; 604 605 if (timer) { 606 if (req->rq_ntrans == 1) 607 rpc_update_rtt(rtt, timer, 608 (long)jiffies - req->rq_xtime); 609 rpc_set_timeo(rtt, timer, req->rq_ntrans - 1); 610 } 611} 612 613/** 614 * xprt_complete_rqst - called when reply processing is complete 615 * @task: RPC request that recently completed 616 * @copied: actual number of bytes received from the transport 617 * 618 * Caller holds transport lock. 619 */ 620void xprt_complete_rqst(struct rpc_task *task, int copied) 621{ 622 struct rpc_rqst *req = task->tk_rqstp; 623 624 dprintk("RPC: %5u xid %08x complete (%d bytes received)\n", 625 task->tk_pid, ntohl(req->rq_xid), copied); 626 627 list_del_init(&req->rq_list); 628 req->rq_received = req->rq_private_buf.len = copied; 629 rpc_wake_up_task(task); 630} 631 632static void xprt_timer(struct rpc_task *task) 633{ 634 struct rpc_rqst *req = task->tk_rqstp; 635 struct rpc_xprt *xprt = req->rq_xprt; 636 637 dprintk("RPC: %4d xprt_timer\n", task->tk_pid); 638 639 spin_lock(&xprt->transport_lock); 640 if (!req->rq_received) { 641 if (xprt->ops->timer) 642 xprt->ops->timer(task); 643 task->tk_status = -ETIMEDOUT; 644 } 645 task->tk_timeout = 0; 646 rpc_wake_up_task(task); 647 spin_unlock(&xprt->transport_lock); 648} 649 650/** 651 * xprt_prepare_transmit - reserve the transport before sending a request 652 * @task: RPC task about to send a request 653 * 654 */ 655int xprt_prepare_transmit(struct rpc_task *task) 656{ 657 struct rpc_rqst *req = task->tk_rqstp; 658 struct rpc_xprt *xprt = req->rq_xprt; 659 int err = 0; 660 661 dprintk("RPC: %4d xprt_prepare_transmit\n", task->tk_pid); 662 663 if (xprt->shutdown) 664 return -EIO; 665 666 spin_lock_bh(&xprt->transport_lock); 667 if (req->rq_received && !req->rq_bytes_sent) { 668 err = req->rq_received; 669 goto out_unlock; 670 } 671 if (!xprt->ops->reserve_xprt(task)) { 672 err = -EAGAIN; 673 goto out_unlock; 674 } 675 676 if (!xprt_connected(xprt)) { 677 err = -ENOTCONN; 678 goto out_unlock; 679 } 680out_unlock: 681 spin_unlock_bh(&xprt->transport_lock); 682 return err; 683} 684 685/** 686 * xprt_transmit - send an RPC request on a transport 687 * @task: controlling RPC task 688 * 689 * We have to copy the iovec because sendmsg fiddles with its contents. 690 */ 691void xprt_transmit(struct rpc_task *task) 692{ 693 struct rpc_rqst *req = task->tk_rqstp; 694 struct rpc_xprt *xprt = req->rq_xprt; 695 int status; 696 697 dprintk("RPC: %4d xprt_transmit(%u)\n", task->tk_pid, req->rq_slen); 698 699 smp_rmb(); 700 if (!req->rq_received) { 701 if (list_empty(&req->rq_list)) { 702 spin_lock_bh(&xprt->transport_lock); 703 /* Update the softirq receive buffer */ 704 memcpy(&req->rq_private_buf, &req->rq_rcv_buf, 705 sizeof(req->rq_private_buf)); 706 /* Add request to the receive list */ 707 list_add_tail(&req->rq_list, &xprt->recv); 708 spin_unlock_bh(&xprt->transport_lock); 709 xprt_reset_majortimeo(req); 710 /* Turn off autodisconnect */ 711 del_singleshot_timer_sync(&xprt->timer); 712 } 713 } else if (!req->rq_bytes_sent) 714 return; 715 716 status = xprt->ops->send_request(task); 717 if (status == 0) { 718 dprintk("RPC: %4d xmit complete\n", task->tk_pid); 719 spin_lock_bh(&xprt->transport_lock); 720 xprt->ops->set_retrans_timeout(task); 721 /* Don't race with disconnect */ 722 if (!xprt_connected(xprt)) 723 task->tk_status = -ENOTCONN; 724 else if (!req->rq_received) 725 rpc_sleep_on(&xprt->pending, task, NULL, xprt_timer); 726 xprt->ops->release_xprt(xprt, task); 727 spin_unlock_bh(&xprt->transport_lock); 728 return; 729 } 730 731 /* Note: at this point, task->tk_sleeping has not yet been set, 732 * hence there is no danger of the waking up task being put on 733 * schedq, and being picked up by a parallel run of rpciod(). 734 */ 735 task->tk_status = status; 736 737 switch (status) { 738 case -ECONNREFUSED: 739 task->tk_timeout = RPC_REESTABLISH_TIMEOUT; 740 rpc_sleep_on(&xprt->sending, task, NULL, NULL); 741 case -EAGAIN: 742 case -ENOTCONN: 743 return; 744 default: 745 break; 746 } 747 xprt_release_write(xprt, task); 748 return; 749} 750 751static inline void do_xprt_reserve(struct rpc_task *task) 752{ 753 struct rpc_xprt *xprt = task->tk_xprt; 754 755 task->tk_status = 0; 756 if (task->tk_rqstp) 757 return; 758 if (!list_empty(&xprt->free)) { 759 struct rpc_rqst *req = list_entry(xprt->free.next, struct rpc_rqst, rq_list); 760 list_del_init(&req->rq_list); 761 task->tk_rqstp = req; 762 xprt_request_init(task, xprt); 763 return; 764 } 765 dprintk("RPC: waiting for request slot\n"); 766 task->tk_status = -EAGAIN; 767 task->tk_timeout = 0; 768 rpc_sleep_on(&xprt->backlog, task, NULL, NULL); 769} 770 771/** 772 * xprt_reserve - allocate an RPC request slot 773 * @task: RPC task requesting a slot allocation 774 * 775 * If no more slots are available, place the task on the transport's 776 * backlog queue. 777 */ 778void xprt_reserve(struct rpc_task *task) 779{ 780 struct rpc_xprt *xprt = task->tk_xprt; 781 782 task->tk_status = -EIO; 783 if (!xprt->shutdown) { 784 spin_lock(&xprt->reserve_lock); 785 do_xprt_reserve(task); 786 spin_unlock(&xprt->reserve_lock); 787 } 788} 789 790static inline u32 xprt_alloc_xid(struct rpc_xprt *xprt) 791{ 792 return xprt->xid++; 793} 794 795static inline void xprt_init_xid(struct rpc_xprt *xprt) 796{ 797 get_random_bytes(&xprt->xid, sizeof(xprt->xid)); 798} 799 800static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt) 801{ 802 struct rpc_rqst *req = task->tk_rqstp; 803 804 req->rq_timeout = xprt->timeout.to_initval; 805 req->rq_task = task; 806 req->rq_xprt = xprt; 807 req->rq_xid = xprt_alloc_xid(xprt); 808 dprintk("RPC: %4d reserved req %p xid %08x\n", task->tk_pid, 809 req, ntohl(req->rq_xid)); 810} 811 812/** 813 * xprt_release - release an RPC request slot 814 * @task: task which is finished with the slot 815 * 816 */ 817void xprt_release(struct rpc_task *task) 818{ 819 struct rpc_xprt *xprt = task->tk_xprt; 820 struct rpc_rqst *req; 821 822 if (!(req = task->tk_rqstp)) 823 return; 824 spin_lock_bh(&xprt->transport_lock); 825 xprt->ops->release_xprt(xprt, task); 826 __xprt_put_cong(xprt, req); 827 if (!list_empty(&req->rq_list)) 828 list_del(&req->rq_list); 829 xprt->last_used = jiffies; 830 if (list_empty(&xprt->recv) && !xprt->shutdown) 831 mod_timer(&xprt->timer, 832 xprt->last_used + RPC_IDLE_DISCONNECT_TIMEOUT); 833 spin_unlock_bh(&xprt->transport_lock); 834 task->tk_rqstp = NULL; 835 memset(req, 0, sizeof(*req)); /* mark unused */ 836 837 dprintk("RPC: %4d release request %p\n", task->tk_pid, req); 838 839 spin_lock(&xprt->reserve_lock); 840 list_add(&req->rq_list, &xprt->free); 841 xprt_clear_backlog(xprt); 842 spin_unlock(&xprt->reserve_lock); 843} 844 845/** 846 * xprt_set_timeout - set constant RPC timeout 847 * @to: RPC timeout parameters to set up 848 * @retr: number of retries 849 * @incr: amount of increase after each retry 850 * 851 */ 852void xprt_set_timeout(struct rpc_timeout *to, unsigned int retr, unsigned long incr) 853{ 854 to->to_initval = 855 to->to_increment = incr; 856 to->to_maxval = to->to_initval + (incr * retr); 857 to->to_retries = retr; 858 to->to_exponential = 0; 859} 860 861static struct rpc_xprt *xprt_setup(int proto, struct sockaddr_in *ap, struct rpc_timeout *to) 862{ 863 int result; 864 struct rpc_xprt *xprt; 865 struct rpc_rqst *req; 866 867 if ((xprt = kmalloc(sizeof(struct rpc_xprt), GFP_KERNEL)) == NULL) 868 return ERR_PTR(-ENOMEM); 869 memset(xprt, 0, sizeof(*xprt)); /* Nnnngh! */ 870 871 xprt->addr = *ap; 872 873 switch (proto) { 874 case IPPROTO_UDP: 875 result = xs_setup_udp(xprt, to); 876 break; 877 case IPPROTO_TCP: 878 result = xs_setup_tcp(xprt, to); 879 break; 880 default: 881 printk(KERN_ERR "RPC: unrecognized transport protocol: %d\n", 882 proto); 883 result = -EIO; 884 break; 885 } 886 if (result) { 887 kfree(xprt); 888 return ERR_PTR(result); 889 } 890 891 spin_lock_init(&xprt->transport_lock); 892 spin_lock_init(&xprt->reserve_lock); 893 init_waitqueue_head(&xprt->cong_wait); 894 895 INIT_LIST_HEAD(&xprt->free); 896 INIT_LIST_HEAD(&xprt->recv); 897 INIT_WORK(&xprt->task_cleanup, xprt_autoclose, xprt); 898 init_timer(&xprt->timer); 899 xprt->timer.function = xprt_init_autodisconnect; 900 xprt->timer.data = (unsigned long) xprt; 901 xprt->last_used = jiffies; 902 903 rpc_init_wait_queue(&xprt->pending, "xprt_pending"); 904 rpc_init_wait_queue(&xprt->sending, "xprt_sending"); 905 rpc_init_wait_queue(&xprt->resend, "xprt_resend"); 906 rpc_init_priority_wait_queue(&xprt->backlog, "xprt_backlog"); 907 908 /* initialize free list */ 909 for (req = &xprt->slot[xprt->max_reqs-1]; req >= &xprt->slot[0]; req--) 910 list_add(&req->rq_list, &xprt->free); 911 912 xprt_init_xid(xprt); 913 914 dprintk("RPC: created transport %p with %u slots\n", xprt, 915 xprt->max_reqs); 916 917 return xprt; 918} 919 920/** 921 * xprt_create_proto - create an RPC client transport 922 * @proto: requested transport protocol 923 * @sap: remote peer's address 924 * @to: timeout parameters for new transport 925 * 926 */ 927struct rpc_xprt *xprt_create_proto(int proto, struct sockaddr_in *sap, struct rpc_timeout *to) 928{ 929 struct rpc_xprt *xprt; 930 931 xprt = xprt_setup(proto, sap, to); 932 if (IS_ERR(xprt)) 933 dprintk("RPC: xprt_create_proto failed\n"); 934 else 935 dprintk("RPC: xprt_create_proto created xprt %p\n", xprt); 936 return xprt; 937} 938 939static void xprt_shutdown(struct rpc_xprt *xprt) 940{ 941 xprt->shutdown = 1; 942 rpc_wake_up(&xprt->sending); 943 rpc_wake_up(&xprt->resend); 944 xprt_wake_pending_tasks(xprt, -EIO); 945 rpc_wake_up(&xprt->backlog); 946 wake_up(&xprt->cong_wait); 947 del_timer_sync(&xprt->timer); 948} 949 950static int xprt_clear_backlog(struct rpc_xprt *xprt) { 951 rpc_wake_up_next(&xprt->backlog); 952 wake_up(&xprt->cong_wait); 953 return 1; 954} 955 956/** 957 * xprt_destroy - destroy an RPC transport, killing off all requests. 958 * @xprt: transport to destroy 959 * 960 */ 961int xprt_destroy(struct rpc_xprt *xprt) 962{ 963 dprintk("RPC: destroying transport %p\n", xprt); 964 xprt_shutdown(xprt); 965 xprt->ops->destroy(xprt); 966 kfree(xprt); 967 968 return 0; 969} 970