xprt.c revision 12a804698b29d040b7cdd92e8a44b0e75164dae9
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} 155 156 157static void __xprt_lock_write_next(struct rpc_xprt *xprt) 158{ 159 struct rpc_task *task; 160 161 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) 162 return; 163 if (!xprt->nocong && RPCXPRT_CONGESTED(xprt)) 164 goto out_unlock; 165 task = rpc_wake_up_next(&xprt->resend); 166 if (!task) { 167 task = rpc_wake_up_next(&xprt->sending); 168 if (!task) 169 goto out_unlock; 170 } 171 if (xprt->nocong || __xprt_get_cong(xprt, task)) { 172 struct rpc_rqst *req = task->tk_rqstp; 173 xprt->snd_task = task; 174 if (req) { 175 req->rq_bytes_sent = 0; 176 req->rq_ntrans++; 177 } 178 return; 179 } 180out_unlock: 181 smp_mb__before_clear_bit(); 182 clear_bit(XPRT_LOCKED, &xprt->state); 183 smp_mb__after_clear_bit(); 184} 185 186/* 187 * Releases the transport for use by other requests. 188 */ 189static void 190__xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task) 191{ 192 if (xprt->snd_task == task) { 193 xprt->snd_task = NULL; 194 smp_mb__before_clear_bit(); 195 clear_bit(XPRT_LOCKED, &xprt->state); 196 smp_mb__after_clear_bit(); 197 __xprt_lock_write_next(xprt); 198 } 199} 200 201static inline void 202xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task) 203{ 204 spin_lock_bh(&xprt->transport_lock); 205 __xprt_release_write(xprt, task); 206 spin_unlock_bh(&xprt->transport_lock); 207} 208 209/* 210 * Van Jacobson congestion avoidance. Check if the congestion window 211 * overflowed. Put the task to sleep if this is the case. 212 */ 213static int 214__xprt_get_cong(struct rpc_xprt *xprt, struct rpc_task *task) 215{ 216 struct rpc_rqst *req = task->tk_rqstp; 217 218 if (req->rq_cong) 219 return 1; 220 dprintk("RPC: %4d xprt_cwnd_limited cong = %ld cwnd = %ld\n", 221 task->tk_pid, xprt->cong, xprt->cwnd); 222 if (RPCXPRT_CONGESTED(xprt)) 223 return 0; 224 req->rq_cong = 1; 225 xprt->cong += RPC_CWNDSCALE; 226 return 1; 227} 228 229/* 230 * Adjust the congestion window, and wake up the next task 231 * that has been sleeping due to congestion 232 */ 233static void 234__xprt_put_cong(struct rpc_xprt *xprt, struct rpc_rqst *req) 235{ 236 if (!req->rq_cong) 237 return; 238 req->rq_cong = 0; 239 xprt->cong -= RPC_CWNDSCALE; 240 __xprt_lock_write_next(xprt); 241} 242 243/* 244 * Adjust RPC congestion window 245 * We use a time-smoothed congestion estimator to avoid heavy oscillation. 246 */ 247static void 248xprt_adjust_cwnd(struct rpc_xprt *xprt, int result) 249{ 250 unsigned long cwnd; 251 252 cwnd = xprt->cwnd; 253 if (result >= 0 && cwnd <= xprt->cong) { 254 /* The (cwnd >> 1) term makes sure 255 * the result gets rounded properly. */ 256 cwnd += (RPC_CWNDSCALE * RPC_CWNDSCALE + (cwnd >> 1)) / cwnd; 257 if (cwnd > RPC_MAXCWND(xprt)) 258 cwnd = RPC_MAXCWND(xprt); 259 __xprt_lock_write_next(xprt); 260 } else if (result == -ETIMEDOUT) { 261 cwnd >>= 1; 262 if (cwnd < RPC_CWNDSCALE) 263 cwnd = RPC_CWNDSCALE; 264 } 265 dprintk("RPC: cong %ld, cwnd was %ld, now %ld\n", 266 xprt->cong, xprt->cwnd, cwnd); 267 xprt->cwnd = cwnd; 268} 269 270/** 271 * xprt_wake_pending_tasks - wake all tasks on a transport's pending queue 272 * @xprt: transport with waiting tasks 273 * @status: result code to plant in each task before waking it 274 * 275 */ 276void xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status) 277{ 278 if (status < 0) 279 rpc_wake_up_status(&xprt->pending, status); 280 else 281 rpc_wake_up(&xprt->pending); 282} 283 284/** 285 * xprt_wait_for_buffer_space - wait for transport output buffer to clear 286 * @task: task to be put to sleep 287 * 288 */ 289void xprt_wait_for_buffer_space(struct rpc_task *task) 290{ 291 struct rpc_rqst *req = task->tk_rqstp; 292 struct rpc_xprt *xprt = req->rq_xprt; 293 294 task->tk_timeout = req->rq_timeout; 295 rpc_sleep_on(&xprt->pending, task, NULL, NULL); 296} 297 298/** 299 * xprt_write_space - wake the task waiting for transport output buffer space 300 * @xprt: transport with waiting tasks 301 * 302 * Can be called in a soft IRQ context, so xprt_write_space never sleeps. 303 */ 304void xprt_write_space(struct rpc_xprt *xprt) 305{ 306 if (unlikely(xprt->shutdown)) 307 return; 308 309 spin_lock_bh(&xprt->transport_lock); 310 if (xprt->snd_task) { 311 dprintk("RPC: write space: waking waiting task on xprt %p\n", 312 xprt); 313 rpc_wake_up_task(xprt->snd_task); 314 } 315 spin_unlock_bh(&xprt->transport_lock); 316} 317 318/** 319 * xprt_set_retrans_timeout_def - set a request's retransmit timeout 320 * @task: task whose timeout is to be set 321 * 322 * Set a request's retransmit timeout based on the transport's 323 * default timeout parameters. Used by transports that don't adjust 324 * the retransmit timeout based on round-trip time estimation. 325 */ 326void xprt_set_retrans_timeout_def(struct rpc_task *task) 327{ 328 task->tk_timeout = task->tk_rqstp->rq_timeout; 329} 330 331/* 332 * xprt_set_retrans_timeout_rtt - set a request's retransmit timeout 333 * @task: task whose timeout is to be set 334 * 335 * Set a request's retransmit timeout using the RTT estimator. 336 */ 337void xprt_set_retrans_timeout_rtt(struct rpc_task *task) 338{ 339 int timer = task->tk_msg.rpc_proc->p_timer; 340 struct rpc_rtt *rtt = task->tk_client->cl_rtt; 341 struct rpc_rqst *req = task->tk_rqstp; 342 unsigned long max_timeout = req->rq_xprt->timeout.to_maxval; 343 344 task->tk_timeout = rpc_calc_rto(rtt, timer); 345 task->tk_timeout <<= rpc_ntimeo(rtt, timer) + req->rq_retries; 346 if (task->tk_timeout > max_timeout || task->tk_timeout == 0) 347 task->tk_timeout = max_timeout; 348} 349 350static void xprt_reset_majortimeo(struct rpc_rqst *req) 351{ 352 struct rpc_timeout *to = &req->rq_xprt->timeout; 353 354 req->rq_majortimeo = req->rq_timeout; 355 if (to->to_exponential) 356 req->rq_majortimeo <<= to->to_retries; 357 else 358 req->rq_majortimeo += to->to_increment * to->to_retries; 359 if (req->rq_majortimeo > to->to_maxval || req->rq_majortimeo == 0) 360 req->rq_majortimeo = to->to_maxval; 361 req->rq_majortimeo += jiffies; 362} 363 364/** 365 * xprt_adjust_timeout - adjust timeout values for next retransmit 366 * @req: RPC request containing parameters to use for the adjustment 367 * 368 */ 369int xprt_adjust_timeout(struct rpc_rqst *req) 370{ 371 struct rpc_xprt *xprt = req->rq_xprt; 372 struct rpc_timeout *to = &xprt->timeout; 373 int status = 0; 374 375 if (time_before(jiffies, req->rq_majortimeo)) { 376 if (to->to_exponential) 377 req->rq_timeout <<= 1; 378 else 379 req->rq_timeout += to->to_increment; 380 if (to->to_maxval && req->rq_timeout >= to->to_maxval) 381 req->rq_timeout = to->to_maxval; 382 req->rq_retries++; 383 pprintk("RPC: %lu retrans\n", jiffies); 384 } else { 385 req->rq_timeout = to->to_initval; 386 req->rq_retries = 0; 387 xprt_reset_majortimeo(req); 388 /* Reset the RTT counters == "slow start" */ 389 spin_lock_bh(&xprt->transport_lock); 390 rpc_init_rtt(req->rq_task->tk_client->cl_rtt, to->to_initval); 391 spin_unlock_bh(&xprt->transport_lock); 392 pprintk("RPC: %lu timeout\n", jiffies); 393 status = -ETIMEDOUT; 394 } 395 396 if (req->rq_timeout == 0) { 397 printk(KERN_WARNING "xprt_adjust_timeout: rq_timeout = 0!\n"); 398 req->rq_timeout = 5 * HZ; 399 } 400 return status; 401} 402 403static void xprt_autoclose(void *args) 404{ 405 struct rpc_xprt *xprt = (struct rpc_xprt *)args; 406 407 xprt_disconnect(xprt); 408 xprt->ops->close(xprt); 409 xprt_release_write(xprt, NULL); 410} 411 412/** 413 * xprt_disconnect - mark a transport as disconnected 414 * @xprt: transport to flag for disconnect 415 * 416 */ 417void xprt_disconnect(struct rpc_xprt *xprt) 418{ 419 dprintk("RPC: disconnected transport %p\n", xprt); 420 spin_lock_bh(&xprt->transport_lock); 421 xprt_clear_connected(xprt); 422 xprt_wake_pending_tasks(xprt, -ENOTCONN); 423 spin_unlock_bh(&xprt->transport_lock); 424} 425 426static void 427xprt_init_autodisconnect(unsigned long data) 428{ 429 struct rpc_xprt *xprt = (struct rpc_xprt *)data; 430 431 spin_lock(&xprt->transport_lock); 432 if (!list_empty(&xprt->recv) || xprt->shutdown) 433 goto out_abort; 434 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) 435 goto out_abort; 436 spin_unlock(&xprt->transport_lock); 437 if (xprt_connecting(xprt)) 438 xprt_release_write(xprt, NULL); 439 else 440 schedule_work(&xprt->task_cleanup); 441 return; 442out_abort: 443 spin_unlock(&xprt->transport_lock); 444} 445 446/** 447 * xprt_connect - schedule a transport connect operation 448 * @task: RPC task that is requesting the connect 449 * 450 */ 451void xprt_connect(struct rpc_task *task) 452{ 453 struct rpc_xprt *xprt = task->tk_xprt; 454 455 dprintk("RPC: %4d xprt_connect xprt %p %s connected\n", task->tk_pid, 456 xprt, (xprt_connected(xprt) ? "is" : "is not")); 457 458 if (xprt->shutdown) { 459 task->tk_status = -EIO; 460 return; 461 } 462 if (!xprt->addr.sin_port) { 463 task->tk_status = -EIO; 464 return; 465 } 466 if (!xprt_lock_write(xprt, task)) 467 return; 468 if (xprt_connected(xprt)) 469 xprt_release_write(xprt, task); 470 else { 471 if (task->tk_rqstp) 472 task->tk_rqstp->rq_bytes_sent = 0; 473 474 task->tk_timeout = RPC_CONNECT_TIMEOUT; 475 rpc_sleep_on(&xprt->pending, task, xprt_connect_status, NULL); 476 xprt->ops->connect(task); 477 } 478 return; 479} 480 481static void xprt_connect_status(struct rpc_task *task) 482{ 483 struct rpc_xprt *xprt = task->tk_xprt; 484 485 if (task->tk_status >= 0) { 486 dprintk("RPC: %4d xprt_connect_status: connection established\n", 487 task->tk_pid); 488 return; 489 } 490 491 switch (task->tk_status) { 492 case -ECONNREFUSED: 493 case -ECONNRESET: 494 dprintk("RPC: %4d xprt_connect_status: server %s refused connection\n", 495 task->tk_pid, task->tk_client->cl_server); 496 break; 497 case -ENOTCONN: 498 dprintk("RPC: %4d xprt_connect_status: connection broken\n", 499 task->tk_pid); 500 break; 501 case -ETIMEDOUT: 502 dprintk("RPC: %4d xprt_connect_status: connect attempt timed out\n", 503 task->tk_pid); 504 break; 505 default: 506 dprintk("RPC: %4d xprt_connect_status: error %d connecting to server %s\n", 507 task->tk_pid, -task->tk_status, task->tk_client->cl_server); 508 xprt_release_write(xprt, task); 509 task->tk_status = -EIO; 510 return; 511 } 512 513 /* if soft mounted, just cause this RPC to fail */ 514 if (RPC_IS_SOFT(task)) { 515 xprt_release_write(xprt, task); 516 task->tk_status = -EIO; 517 } 518} 519 520/** 521 * xprt_lookup_rqst - find an RPC request corresponding to an XID 522 * @xprt: transport on which the original request was transmitted 523 * @xid: RPC XID of incoming reply 524 * 525 */ 526struct rpc_rqst *xprt_lookup_rqst(struct rpc_xprt *xprt, u32 xid) 527{ 528 struct list_head *pos; 529 struct rpc_rqst *req = NULL; 530 531 list_for_each(pos, &xprt->recv) { 532 struct rpc_rqst *entry = list_entry(pos, struct rpc_rqst, rq_list); 533 if (entry->rq_xid == xid) { 534 req = entry; 535 break; 536 } 537 } 538 return req; 539} 540 541/** 542 * xprt_complete_rqst - called when reply processing is complete 543 * @xprt: controlling transport 544 * @req: RPC request that just completed 545 * @copied: actual number of bytes received from the transport 546 * 547 */ 548void xprt_complete_rqst(struct rpc_xprt *xprt, struct rpc_rqst *req, int copied) 549{ 550 struct rpc_task *task = req->rq_task; 551 struct rpc_clnt *clnt = task->tk_client; 552 553 /* Adjust congestion window */ 554 if (!xprt->nocong) { 555 unsigned timer = task->tk_msg.rpc_proc->p_timer; 556 xprt_adjust_cwnd(xprt, copied); 557 __xprt_put_cong(xprt, req); 558 if (timer) { 559 if (req->rq_ntrans == 1) 560 rpc_update_rtt(clnt->cl_rtt, timer, 561 (long)jiffies - req->rq_xtime); 562 rpc_set_timeo(clnt->cl_rtt, timer, req->rq_ntrans - 1); 563 } 564 } 565 566#ifdef RPC_PROFILE 567 /* Profile only reads for now */ 568 if (copied > 1024) { 569 static unsigned long nextstat; 570 static unsigned long pkt_rtt, pkt_len, pkt_cnt; 571 572 pkt_cnt++; 573 pkt_len += req->rq_slen + copied; 574 pkt_rtt += jiffies - req->rq_xtime; 575 if (time_before(nextstat, jiffies)) { 576 printk("RPC: %lu %ld cwnd\n", jiffies, xprt->cwnd); 577 printk("RPC: %ld %ld %ld %ld stat\n", 578 jiffies, pkt_cnt, pkt_len, pkt_rtt); 579 pkt_rtt = pkt_len = pkt_cnt = 0; 580 nextstat = jiffies + 5 * HZ; 581 } 582 } 583#endif 584 585 dprintk("RPC: %4d has input (%d bytes)\n", task->tk_pid, copied); 586 list_del_init(&req->rq_list); 587 req->rq_received = req->rq_private_buf.len = copied; 588 589 /* ... and wake up the process. */ 590 rpc_wake_up_task(task); 591 return; 592} 593 594/* 595 * RPC receive timeout handler. 596 */ 597static void 598xprt_timer(struct rpc_task *task) 599{ 600 struct rpc_rqst *req = task->tk_rqstp; 601 struct rpc_xprt *xprt = req->rq_xprt; 602 603 spin_lock(&xprt->transport_lock); 604 if (req->rq_received) 605 goto out; 606 607 xprt_adjust_cwnd(req->rq_xprt, -ETIMEDOUT); 608 __xprt_put_cong(xprt, req); 609 610 dprintk("RPC: %4d xprt_timer (%s request)\n", 611 task->tk_pid, req ? "pending" : "backlogged"); 612 613 task->tk_status = -ETIMEDOUT; 614out: 615 task->tk_timeout = 0; 616 rpc_wake_up_task(task); 617 spin_unlock(&xprt->transport_lock); 618} 619 620/** 621 * xprt_prepare_transmit - reserve the transport before sending a request 622 * @task: RPC task about to send a request 623 * 624 */ 625int xprt_prepare_transmit(struct rpc_task *task) 626{ 627 struct rpc_rqst *req = task->tk_rqstp; 628 struct rpc_xprt *xprt = req->rq_xprt; 629 int err = 0; 630 631 dprintk("RPC: %4d xprt_prepare_transmit\n", task->tk_pid); 632 633 if (xprt->shutdown) 634 return -EIO; 635 636 spin_lock_bh(&xprt->transport_lock); 637 if (req->rq_received && !req->rq_bytes_sent) { 638 err = req->rq_received; 639 goto out_unlock; 640 } 641 if (!xprt->ops->reserve_xprt(task)) { 642 err = -EAGAIN; 643 goto out_unlock; 644 } 645 646 if (!xprt_connected(xprt)) { 647 err = -ENOTCONN; 648 goto out_unlock; 649 } 650out_unlock: 651 spin_unlock_bh(&xprt->transport_lock); 652 return err; 653} 654 655/** 656 * xprt_transmit - send an RPC request on a transport 657 * @task: controlling RPC task 658 * 659 * We have to copy the iovec because sendmsg fiddles with its contents. 660 */ 661void xprt_transmit(struct rpc_task *task) 662{ 663 struct rpc_rqst *req = task->tk_rqstp; 664 struct rpc_xprt *xprt = req->rq_xprt; 665 int status; 666 667 dprintk("RPC: %4d xprt_transmit(%u)\n", task->tk_pid, req->rq_slen); 668 669 smp_rmb(); 670 if (!req->rq_received) { 671 if (list_empty(&req->rq_list)) { 672 spin_lock_bh(&xprt->transport_lock); 673 /* Update the softirq receive buffer */ 674 memcpy(&req->rq_private_buf, &req->rq_rcv_buf, 675 sizeof(req->rq_private_buf)); 676 /* Add request to the receive list */ 677 list_add_tail(&req->rq_list, &xprt->recv); 678 spin_unlock_bh(&xprt->transport_lock); 679 xprt_reset_majortimeo(req); 680 /* Turn off autodisconnect */ 681 del_singleshot_timer_sync(&xprt->timer); 682 } 683 } else if (!req->rq_bytes_sent) 684 return; 685 686 status = xprt->ops->send_request(task); 687 if (status == 0) { 688 dprintk("RPC: %4d xmit complete\n", task->tk_pid); 689 spin_lock_bh(&xprt->transport_lock); 690 xprt->ops->set_retrans_timeout(task); 691 /* Don't race with disconnect */ 692 if (!xprt_connected(xprt)) 693 task->tk_status = -ENOTCONN; 694 else if (!req->rq_received) 695 rpc_sleep_on(&xprt->pending, task, NULL, xprt_timer); 696 __xprt_release_write(xprt, task); 697 spin_unlock_bh(&xprt->transport_lock); 698 return; 699 } 700 701 /* Note: at this point, task->tk_sleeping has not yet been set, 702 * hence there is no danger of the waking up task being put on 703 * schedq, and being picked up by a parallel run of rpciod(). 704 */ 705 task->tk_status = status; 706 707 switch (status) { 708 case -ECONNREFUSED: 709 task->tk_timeout = RPC_REESTABLISH_TIMEOUT; 710 rpc_sleep_on(&xprt->sending, task, NULL, NULL); 711 case -EAGAIN: 712 case -ENOTCONN: 713 return; 714 default: 715 break; 716 } 717 xprt_release_write(xprt, task); 718 return; 719} 720 721static inline void do_xprt_reserve(struct rpc_task *task) 722{ 723 struct rpc_xprt *xprt = task->tk_xprt; 724 725 task->tk_status = 0; 726 if (task->tk_rqstp) 727 return; 728 if (!list_empty(&xprt->free)) { 729 struct rpc_rqst *req = list_entry(xprt->free.next, struct rpc_rqst, rq_list); 730 list_del_init(&req->rq_list); 731 task->tk_rqstp = req; 732 xprt_request_init(task, xprt); 733 return; 734 } 735 dprintk("RPC: waiting for request slot\n"); 736 task->tk_status = -EAGAIN; 737 task->tk_timeout = 0; 738 rpc_sleep_on(&xprt->backlog, task, NULL, NULL); 739} 740 741/** 742 * xprt_reserve - allocate an RPC request slot 743 * @task: RPC task requesting a slot allocation 744 * 745 * If no more slots are available, place the task on the transport's 746 * backlog queue. 747 */ 748void xprt_reserve(struct rpc_task *task) 749{ 750 struct rpc_xprt *xprt = task->tk_xprt; 751 752 task->tk_status = -EIO; 753 if (!xprt->shutdown) { 754 spin_lock(&xprt->reserve_lock); 755 do_xprt_reserve(task); 756 spin_unlock(&xprt->reserve_lock); 757 } 758} 759 760static inline u32 xprt_alloc_xid(struct rpc_xprt *xprt) 761{ 762 return xprt->xid++; 763} 764 765static inline void xprt_init_xid(struct rpc_xprt *xprt) 766{ 767 get_random_bytes(&xprt->xid, sizeof(xprt->xid)); 768} 769 770static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt) 771{ 772 struct rpc_rqst *req = task->tk_rqstp; 773 774 req->rq_timeout = xprt->timeout.to_initval; 775 req->rq_task = task; 776 req->rq_xprt = xprt; 777 req->rq_xid = xprt_alloc_xid(xprt); 778 dprintk("RPC: %4d reserved req %p xid %08x\n", task->tk_pid, 779 req, ntohl(req->rq_xid)); 780} 781 782/** 783 * xprt_release - release an RPC request slot 784 * @task: task which is finished with the slot 785 * 786 */ 787void xprt_release(struct rpc_task *task) 788{ 789 struct rpc_xprt *xprt = task->tk_xprt; 790 struct rpc_rqst *req; 791 792 if (!(req = task->tk_rqstp)) 793 return; 794 spin_lock_bh(&xprt->transport_lock); 795 __xprt_release_write(xprt, task); 796 __xprt_put_cong(xprt, req); 797 if (!list_empty(&req->rq_list)) 798 list_del(&req->rq_list); 799 xprt->last_used = jiffies; 800 if (list_empty(&xprt->recv) && !xprt->shutdown) 801 mod_timer(&xprt->timer, 802 xprt->last_used + RPC_IDLE_DISCONNECT_TIMEOUT); 803 spin_unlock_bh(&xprt->transport_lock); 804 task->tk_rqstp = NULL; 805 memset(req, 0, sizeof(*req)); /* mark unused */ 806 807 dprintk("RPC: %4d release request %p\n", task->tk_pid, req); 808 809 spin_lock(&xprt->reserve_lock); 810 list_add(&req->rq_list, &xprt->free); 811 xprt_clear_backlog(xprt); 812 spin_unlock(&xprt->reserve_lock); 813} 814 815/** 816 * xprt_set_timeout - set constant RPC timeout 817 * @to: RPC timeout parameters to set up 818 * @retr: number of retries 819 * @incr: amount of increase after each retry 820 * 821 */ 822void xprt_set_timeout(struct rpc_timeout *to, unsigned int retr, unsigned long incr) 823{ 824 to->to_initval = 825 to->to_increment = incr; 826 to->to_maxval = to->to_initval + (incr * retr); 827 to->to_retries = retr; 828 to->to_exponential = 0; 829} 830 831static struct rpc_xprt *xprt_setup(int proto, struct sockaddr_in *ap, struct rpc_timeout *to) 832{ 833 int result; 834 struct rpc_xprt *xprt; 835 struct rpc_rqst *req; 836 837 if ((xprt = kmalloc(sizeof(struct rpc_xprt), GFP_KERNEL)) == NULL) 838 return ERR_PTR(-ENOMEM); 839 memset(xprt, 0, sizeof(*xprt)); /* Nnnngh! */ 840 841 xprt->addr = *ap; 842 843 switch (proto) { 844 case IPPROTO_UDP: 845 result = xs_setup_udp(xprt, to); 846 break; 847 case IPPROTO_TCP: 848 result = xs_setup_tcp(xprt, to); 849 break; 850 default: 851 printk(KERN_ERR "RPC: unrecognized transport protocol: %d\n", 852 proto); 853 result = -EIO; 854 break; 855 } 856 if (result) { 857 kfree(xprt); 858 return ERR_PTR(result); 859 } 860 861 spin_lock_init(&xprt->transport_lock); 862 spin_lock_init(&xprt->reserve_lock); 863 init_waitqueue_head(&xprt->cong_wait); 864 865 INIT_LIST_HEAD(&xprt->free); 866 INIT_LIST_HEAD(&xprt->recv); 867 INIT_WORK(&xprt->task_cleanup, xprt_autoclose, xprt); 868 init_timer(&xprt->timer); 869 xprt->timer.function = xprt_init_autodisconnect; 870 xprt->timer.data = (unsigned long) xprt; 871 xprt->last_used = jiffies; 872 873 rpc_init_wait_queue(&xprt->pending, "xprt_pending"); 874 rpc_init_wait_queue(&xprt->sending, "xprt_sending"); 875 rpc_init_wait_queue(&xprt->resend, "xprt_resend"); 876 rpc_init_priority_wait_queue(&xprt->backlog, "xprt_backlog"); 877 878 /* initialize free list */ 879 for (req = &xprt->slot[xprt->max_reqs-1]; req >= &xprt->slot[0]; req--) 880 list_add(&req->rq_list, &xprt->free); 881 882 xprt_init_xid(xprt); 883 884 dprintk("RPC: created transport %p with %u slots\n", xprt, 885 xprt->max_reqs); 886 887 return xprt; 888} 889 890/** 891 * xprt_create_proto - create an RPC client transport 892 * @proto: requested transport protocol 893 * @sap: remote peer's address 894 * @to: timeout parameters for new transport 895 * 896 */ 897struct rpc_xprt *xprt_create_proto(int proto, struct sockaddr_in *sap, struct rpc_timeout *to) 898{ 899 struct rpc_xprt *xprt; 900 901 xprt = xprt_setup(proto, sap, to); 902 if (IS_ERR(xprt)) 903 dprintk("RPC: xprt_create_proto failed\n"); 904 else 905 dprintk("RPC: xprt_create_proto created xprt %p\n", xprt); 906 return xprt; 907} 908 909static void xprt_shutdown(struct rpc_xprt *xprt) 910{ 911 xprt->shutdown = 1; 912 rpc_wake_up(&xprt->sending); 913 rpc_wake_up(&xprt->resend); 914 xprt_wake_pending_tasks(xprt, -EIO); 915 rpc_wake_up(&xprt->backlog); 916 wake_up(&xprt->cong_wait); 917 del_timer_sync(&xprt->timer); 918} 919 920static int xprt_clear_backlog(struct rpc_xprt *xprt) { 921 rpc_wake_up_next(&xprt->backlog); 922 wake_up(&xprt->cong_wait); 923 return 1; 924} 925 926/** 927 * xprt_destroy - destroy an RPC transport, killing off all requests. 928 * @xprt: transport to destroy 929 * 930 */ 931int xprt_destroy(struct rpc_xprt *xprt) 932{ 933 dprintk("RPC: destroying transport %p\n", xprt); 934 xprt_shutdown(xprt); 935 xprt->ops->destroy(xprt); 936 kfree(xprt); 937 938 return 0; 939} 940