[PATCH] RPC: Eliminate socket.h includes in RPC client
[linux-2.6.git] / net / sunrpc / xprt.c
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_call().
14  *  -   xprt_call transmits the message and installs the caller on the
15  *      socket'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 socket. 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
37 #include <linux/module.h>
38
39 #include <linux/types.h>
40 #include <linux/interrupt.h>
41 #include <linux/workqueue.h>
42 #include <linux/random.h>
43
44 #include <linux/sunrpc/clnt.h>
45
46 /*
47  * Local variables
48  */
49
50 #ifdef RPC_DEBUG
51 # undef  RPC_DEBUG_DATA
52 # define RPCDBG_FACILITY        RPCDBG_XPRT
53 #endif
54
55 #define XPRT_MAX_BACKOFF        (8)
56
57 /*
58  * Local functions
59  */
60 static void     xprt_request_init(struct rpc_task *, struct rpc_xprt *);
61 static inline void      do_xprt_reserve(struct rpc_task *);
62 static void     xprt_connect_status(struct rpc_task *task);
63 static int      __xprt_get_cong(struct rpc_xprt *, struct rpc_task *);
64
65 static int      xprt_clear_backlog(struct rpc_xprt *xprt);
66
67 /*
68  * Serialize write access to sockets, in order to prevent different
69  * requests from interfering with each other.
70  * Also prevents TCP socket connects from colliding with writes.
71  */
72 static int
73 __xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task)
74 {
75         struct rpc_rqst *req = task->tk_rqstp;
76
77         if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
78                 if (task == xprt->snd_task)
79                         return 1;
80                 goto out_sleep;
81         }
82         if (xprt->nocong || __xprt_get_cong(xprt, task)) {
83                 xprt->snd_task = task;
84                 if (req) {
85                         req->rq_bytes_sent = 0;
86                         req->rq_ntrans++;
87                 }
88                 return 1;
89         }
90         smp_mb__before_clear_bit();
91         clear_bit(XPRT_LOCKED, &xprt->state);
92         smp_mb__after_clear_bit();
93 out_sleep:
94         dprintk("RPC: %4d failed to lock socket %p\n", task->tk_pid, xprt);
95         task->tk_timeout = 0;
96         task->tk_status = -EAGAIN;
97         if (req && req->rq_ntrans)
98                 rpc_sleep_on(&xprt->resend, task, NULL, NULL);
99         else
100                 rpc_sleep_on(&xprt->sending, task, NULL, NULL);
101         return 0;
102 }
103
104 static inline int
105 xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task)
106 {
107         int retval;
108
109         spin_lock_bh(&xprt->transport_lock);
110         retval = __xprt_lock_write(xprt, task);
111         spin_unlock_bh(&xprt->transport_lock);
112         return retval;
113 }
114
115
116 static void
117 __xprt_lock_write_next(struct rpc_xprt *xprt)
118 {
119         struct rpc_task *task;
120
121         if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
122                 return;
123         if (!xprt->nocong && RPCXPRT_CONGESTED(xprt))
124                 goto out_unlock;
125         task = rpc_wake_up_next(&xprt->resend);
126         if (!task) {
127                 task = rpc_wake_up_next(&xprt->sending);
128                 if (!task)
129                         goto out_unlock;
130         }
131         if (xprt->nocong || __xprt_get_cong(xprt, task)) {
132                 struct rpc_rqst *req = task->tk_rqstp;
133                 xprt->snd_task = task;
134                 if (req) {
135                         req->rq_bytes_sent = 0;
136                         req->rq_ntrans++;
137                 }
138                 return;
139         }
140 out_unlock:
141         smp_mb__before_clear_bit();
142         clear_bit(XPRT_LOCKED, &xprt->state);
143         smp_mb__after_clear_bit();
144 }
145
146 /*
147  * Releases the socket for use by other requests.
148  */
149 static void
150 __xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task)
151 {
152         if (xprt->snd_task == task) {
153                 xprt->snd_task = NULL;
154                 smp_mb__before_clear_bit();
155                 clear_bit(XPRT_LOCKED, &xprt->state);
156                 smp_mb__after_clear_bit();
157                 __xprt_lock_write_next(xprt);
158         }
159 }
160
161 static inline void
162 xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task)
163 {
164         spin_lock_bh(&xprt->transport_lock);
165         __xprt_release_write(xprt, task);
166         spin_unlock_bh(&xprt->transport_lock);
167 }
168
169 /*
170  * Van Jacobson congestion avoidance. Check if the congestion window
171  * overflowed. Put the task to sleep if this is the case.
172  */
173 static int
174 __xprt_get_cong(struct rpc_xprt *xprt, struct rpc_task *task)
175 {
176         struct rpc_rqst *req = task->tk_rqstp;
177
178         if (req->rq_cong)
179                 return 1;
180         dprintk("RPC: %4d xprt_cwnd_limited cong = %ld cwnd = %ld\n",
181                         task->tk_pid, xprt->cong, xprt->cwnd);
182         if (RPCXPRT_CONGESTED(xprt))
183                 return 0;
184         req->rq_cong = 1;
185         xprt->cong += RPC_CWNDSCALE;
186         return 1;
187 }
188
189 /*
190  * Adjust the congestion window, and wake up the next task
191  * that has been sleeping due to congestion
192  */
193 static void
194 __xprt_put_cong(struct rpc_xprt *xprt, struct rpc_rqst *req)
195 {
196         if (!req->rq_cong)
197                 return;
198         req->rq_cong = 0;
199         xprt->cong -= RPC_CWNDSCALE;
200         __xprt_lock_write_next(xprt);
201 }
202
203 /*
204  * Adjust RPC congestion window
205  * We use a time-smoothed congestion estimator to avoid heavy oscillation.
206  */
207 static void
208 xprt_adjust_cwnd(struct rpc_xprt *xprt, int result)
209 {
210         unsigned long   cwnd;
211
212         cwnd = xprt->cwnd;
213         if (result >= 0 && cwnd <= xprt->cong) {
214                 /* The (cwnd >> 1) term makes sure
215                  * the result gets rounded properly. */
216                 cwnd += (RPC_CWNDSCALE * RPC_CWNDSCALE + (cwnd >> 1)) / cwnd;
217                 if (cwnd > RPC_MAXCWND(xprt))
218                         cwnd = RPC_MAXCWND(xprt);
219                 __xprt_lock_write_next(xprt);
220         } else if (result == -ETIMEDOUT) {
221                 cwnd >>= 1;
222                 if (cwnd < RPC_CWNDSCALE)
223                         cwnd = RPC_CWNDSCALE;
224         }
225         dprintk("RPC:      cong %ld, cwnd was %ld, now %ld\n",
226                         xprt->cong, xprt->cwnd, cwnd);
227         xprt->cwnd = cwnd;
228 }
229
230 static void xprt_reset_majortimeo(struct rpc_rqst *req)
231 {
232         struct rpc_timeout *to = &req->rq_xprt->timeout;
233
234         req->rq_majortimeo = req->rq_timeout;
235         if (to->to_exponential)
236                 req->rq_majortimeo <<= to->to_retries;
237         else
238                 req->rq_majortimeo += to->to_increment * to->to_retries;
239         if (req->rq_majortimeo > to->to_maxval || req->rq_majortimeo == 0)
240                 req->rq_majortimeo = to->to_maxval;
241         req->rq_majortimeo += jiffies;
242 }
243
244 /**
245  * xprt_adjust_timeout - adjust timeout values for next retransmit
246  * @req: RPC request containing parameters to use for the adjustment
247  *
248  */
249 int xprt_adjust_timeout(struct rpc_rqst *req)
250 {
251         struct rpc_xprt *xprt = req->rq_xprt;
252         struct rpc_timeout *to = &xprt->timeout;
253         int status = 0;
254
255         if (time_before(jiffies, req->rq_majortimeo)) {
256                 if (to->to_exponential)
257                         req->rq_timeout <<= 1;
258                 else
259                         req->rq_timeout += to->to_increment;
260                 if (to->to_maxval && req->rq_timeout >= to->to_maxval)
261                         req->rq_timeout = to->to_maxval;
262                 req->rq_retries++;
263                 pprintk("RPC: %lu retrans\n", jiffies);
264         } else {
265                 req->rq_timeout = to->to_initval;
266                 req->rq_retries = 0;
267                 xprt_reset_majortimeo(req);
268                 /* Reset the RTT counters == "slow start" */
269                 spin_lock_bh(&xprt->transport_lock);
270                 rpc_init_rtt(req->rq_task->tk_client->cl_rtt, to->to_initval);
271                 spin_unlock_bh(&xprt->transport_lock);
272                 pprintk("RPC: %lu timeout\n", jiffies);
273                 status = -ETIMEDOUT;
274         }
275
276         if (req->rq_timeout == 0) {
277                 printk(KERN_WARNING "xprt_adjust_timeout: rq_timeout = 0!\n");
278                 req->rq_timeout = 5 * HZ;
279         }
280         return status;
281 }
282
283 static void
284 xprt_socket_autoclose(void *args)
285 {
286         struct rpc_xprt *xprt = (struct rpc_xprt *)args;
287
288         xprt_disconnect(xprt);
289         xprt->ops->close(xprt);
290         xprt_release_write(xprt, NULL);
291 }
292
293 /**
294  * xprt_disconnect - mark a transport as disconnected
295  * @xprt: transport to flag for disconnect
296  *
297  */
298 void xprt_disconnect(struct rpc_xprt *xprt)
299 {
300         dprintk("RPC:      disconnected transport %p\n", xprt);
301         spin_lock_bh(&xprt->transport_lock);
302         xprt_clear_connected(xprt);
303         rpc_wake_up_status(&xprt->pending, -ENOTCONN);
304         spin_unlock_bh(&xprt->transport_lock);
305 }
306
307 static void
308 xprt_init_autodisconnect(unsigned long data)
309 {
310         struct rpc_xprt *xprt = (struct rpc_xprt *)data;
311
312         spin_lock(&xprt->transport_lock);
313         if (!list_empty(&xprt->recv) || xprt->shutdown)
314                 goto out_abort;
315         if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
316                 goto out_abort;
317         spin_unlock(&xprt->transport_lock);
318         /* Let keventd close the socket */
319         if (xprt_connecting(xprt))
320                 xprt_release_write(xprt, NULL);
321         else
322                 schedule_work(&xprt->task_cleanup);
323         return;
324 out_abort:
325         spin_unlock(&xprt->transport_lock);
326 }
327
328 /**
329  * xprt_connect - schedule a transport connect operation
330  * @task: RPC task that is requesting the connect
331  *
332  */
333 void xprt_connect(struct rpc_task *task)
334 {
335         struct rpc_xprt *xprt = task->tk_xprt;
336
337         dprintk("RPC: %4d xprt_connect xprt %p %s connected\n", task->tk_pid,
338                         xprt, (xprt_connected(xprt) ? "is" : "is not"));
339
340         if (xprt->shutdown) {
341                 task->tk_status = -EIO;
342                 return;
343         }
344         if (!xprt->addr.sin_port) {
345                 task->tk_status = -EIO;
346                 return;
347         }
348         if (!xprt_lock_write(xprt, task))
349                 return;
350         if (xprt_connected(xprt))
351                 xprt_release_write(xprt, task);
352         else {
353                 if (task->tk_rqstp)
354                         task->tk_rqstp->rq_bytes_sent = 0;
355
356                 task->tk_timeout = RPC_CONNECT_TIMEOUT;
357                 rpc_sleep_on(&xprt->pending, task, xprt_connect_status, NULL);
358                 xprt->ops->connect(task);
359         }
360         return;
361 }
362
363 static void xprt_connect_status(struct rpc_task *task)
364 {
365         struct rpc_xprt *xprt = task->tk_xprt;
366
367         if (task->tk_status >= 0) {
368                 dprintk("RPC: %4d xprt_connect_status: connection established\n",
369                                 task->tk_pid);
370                 return;
371         }
372
373         switch (task->tk_status) {
374         case -ECONNREFUSED:
375         case -ECONNRESET:
376                 dprintk("RPC: %4d xprt_connect_status: server %s refused connection\n",
377                                 task->tk_pid, task->tk_client->cl_server);
378                 break;
379         case -ENOTCONN:
380                 dprintk("RPC: %4d xprt_connect_status: connection broken\n",
381                                 task->tk_pid);
382                 break;
383         case -ETIMEDOUT:
384                 dprintk("RPC: %4d xprt_connect_status: connect attempt timed out\n",
385                                 task->tk_pid);
386                 break;
387         default:
388                 dprintk("RPC: %4d xprt_connect_status: error %d connecting to server %s\n",
389                                 task->tk_pid, -task->tk_status, task->tk_client->cl_server);
390                 xprt_release_write(xprt, task);
391                 task->tk_status = -EIO;
392                 return;
393         }
394
395         /* if soft mounted, just cause this RPC to fail */
396         if (RPC_IS_SOFT(task)) {
397                 xprt_release_write(xprt, task);
398                 task->tk_status = -EIO;
399         }
400 }
401
402 /**
403  * xprt_lookup_rqst - find an RPC request corresponding to an XID
404  * @xprt: transport on which the original request was transmitted
405  * @xid: RPC XID of incoming reply
406  *
407  */
408 struct rpc_rqst *xprt_lookup_rqst(struct rpc_xprt *xprt, u32 xid)
409 {
410         struct list_head *pos;
411         struct rpc_rqst *req = NULL;
412
413         list_for_each(pos, &xprt->recv) {
414                 struct rpc_rqst *entry = list_entry(pos, struct rpc_rqst, rq_list);
415                 if (entry->rq_xid == xid) {
416                         req = entry;
417                         break;
418                 }
419         }
420         return req;
421 }
422
423 /**
424  * xprt_complete_rqst - called when reply processing is complete
425  * @xprt: controlling transport
426  * @req: RPC request that just completed
427  * @copied: actual number of bytes received from the transport
428  *
429  */
430 void xprt_complete_rqst(struct rpc_xprt *xprt, struct rpc_rqst *req, int copied)
431 {
432         struct rpc_task *task = req->rq_task;
433         struct rpc_clnt *clnt = task->tk_client;
434
435         /* Adjust congestion window */
436         if (!xprt->nocong) {
437                 unsigned timer = task->tk_msg.rpc_proc->p_timer;
438                 xprt_adjust_cwnd(xprt, copied);
439                 __xprt_put_cong(xprt, req);
440                 if (timer) {
441                         if (req->rq_ntrans == 1)
442                                 rpc_update_rtt(clnt->cl_rtt, timer,
443                                                 (long)jiffies - req->rq_xtime);
444                         rpc_set_timeo(clnt->cl_rtt, timer, req->rq_ntrans - 1);
445                 }
446         }
447
448 #ifdef RPC_PROFILE
449         /* Profile only reads for now */
450         if (copied > 1024) {
451                 static unsigned long    nextstat;
452                 static unsigned long    pkt_rtt, pkt_len, pkt_cnt;
453
454                 pkt_cnt++;
455                 pkt_len += req->rq_slen + copied;
456                 pkt_rtt += jiffies - req->rq_xtime;
457                 if (time_before(nextstat, jiffies)) {
458                         printk("RPC: %lu %ld cwnd\n", jiffies, xprt->cwnd);
459                         printk("RPC: %ld %ld %ld %ld stat\n",
460                                         jiffies, pkt_cnt, pkt_len, pkt_rtt);
461                         pkt_rtt = pkt_len = pkt_cnt = 0;
462                         nextstat = jiffies + 5 * HZ;
463                 }
464         }
465 #endif
466
467         dprintk("RPC: %4d has input (%d bytes)\n", task->tk_pid, copied);
468         list_del_init(&req->rq_list);
469         req->rq_received = req->rq_private_buf.len = copied;
470
471         /* ... and wake up the process. */
472         rpc_wake_up_task(task);
473         return;
474 }
475
476 /*
477  * RPC receive timeout handler.
478  */
479 static void
480 xprt_timer(struct rpc_task *task)
481 {
482         struct rpc_rqst *req = task->tk_rqstp;
483         struct rpc_xprt *xprt = req->rq_xprt;
484
485         spin_lock(&xprt->transport_lock);
486         if (req->rq_received)
487                 goto out;
488
489         xprt_adjust_cwnd(req->rq_xprt, -ETIMEDOUT);
490         __xprt_put_cong(xprt, req);
491
492         dprintk("RPC: %4d xprt_timer (%s request)\n",
493                 task->tk_pid, req ? "pending" : "backlogged");
494
495         task->tk_status  = -ETIMEDOUT;
496 out:
497         task->tk_timeout = 0;
498         rpc_wake_up_task(task);
499         spin_unlock(&xprt->transport_lock);
500 }
501
502 /**
503  * xprt_prepare_transmit - reserve the transport before sending a request
504  * @task: RPC task about to send a request
505  *
506  */
507 int xprt_prepare_transmit(struct rpc_task *task)
508 {
509         struct rpc_rqst *req = task->tk_rqstp;
510         struct rpc_xprt *xprt = req->rq_xprt;
511         int err = 0;
512
513         dprintk("RPC: %4d xprt_prepare_transmit\n", task->tk_pid);
514
515         if (xprt->shutdown)
516                 return -EIO;
517
518         spin_lock_bh(&xprt->transport_lock);
519         if (req->rq_received && !req->rq_bytes_sent) {
520                 err = req->rq_received;
521                 goto out_unlock;
522         }
523         if (!__xprt_lock_write(xprt, task)) {
524                 err = -EAGAIN;
525                 goto out_unlock;
526         }
527
528         if (!xprt_connected(xprt)) {
529                 err = -ENOTCONN;
530                 goto out_unlock;
531         }
532 out_unlock:
533         spin_unlock_bh(&xprt->transport_lock);
534         return err;
535 }
536
537 /**
538  * xprt_transmit - send an RPC request on a transport
539  * @task: controlling RPC task
540  *
541  * We have to copy the iovec because sendmsg fiddles with its contents.
542  */
543 void xprt_transmit(struct rpc_task *task)
544 {
545         struct rpc_clnt *clnt = task->tk_client;
546         struct rpc_rqst *req = task->tk_rqstp;
547         struct rpc_xprt *xprt = req->rq_xprt;
548         int status;
549
550         dprintk("RPC: %4d xprt_transmit(%u)\n", task->tk_pid, req->rq_slen);
551
552         smp_rmb();
553         if (!req->rq_received) {
554                 if (list_empty(&req->rq_list)) {
555                         spin_lock_bh(&xprt->transport_lock);
556                         /* Update the softirq receive buffer */
557                         memcpy(&req->rq_private_buf, &req->rq_rcv_buf,
558                                         sizeof(req->rq_private_buf));
559                         /* Add request to the receive list */
560                         list_add_tail(&req->rq_list, &xprt->recv);
561                         spin_unlock_bh(&xprt->transport_lock);
562                         xprt_reset_majortimeo(req);
563                         /* Turn off autodisconnect */
564                         del_singleshot_timer_sync(&xprt->timer);
565                 }
566         } else if (!req->rq_bytes_sent)
567                 return;
568
569         status = xprt->ops->send_request(task);
570         if (!status)
571                 goto out_receive;
572
573         /* Note: at this point, task->tk_sleeping has not yet been set,
574          *       hence there is no danger of the waking up task being put on
575          *       schedq, and being picked up by a parallel run of rpciod().
576          */
577         task->tk_status = status;
578
579         switch (status) {
580         case -ECONNREFUSED:
581                 task->tk_timeout = RPC_REESTABLISH_TIMEOUT;
582                 rpc_sleep_on(&xprt->sending, task, NULL, NULL);
583         case -EAGAIN:
584         case -ENOTCONN:
585                 return;
586         default:
587                 if (xprt->stream)
588                         xprt_disconnect(xprt);
589         }
590         xprt_release_write(xprt, task);
591         return;
592  out_receive:
593         dprintk("RPC: %4d xmit complete\n", task->tk_pid);
594         /* Set the task's receive timeout value */
595         spin_lock_bh(&xprt->transport_lock);
596         if (!xprt->nocong) {
597                 int timer = task->tk_msg.rpc_proc->p_timer;
598                 task->tk_timeout = rpc_calc_rto(clnt->cl_rtt, timer);
599                 task->tk_timeout <<= rpc_ntimeo(clnt->cl_rtt, timer) + req->rq_retries;
600                 if (task->tk_timeout > xprt->timeout.to_maxval || task->tk_timeout == 0)
601                         task->tk_timeout = xprt->timeout.to_maxval;
602         } else
603                 task->tk_timeout = req->rq_timeout;
604         /* Don't race with disconnect */
605         if (!xprt_connected(xprt))
606                 task->tk_status = -ENOTCONN;
607         else if (!req->rq_received)
608                 rpc_sleep_on(&xprt->pending, task, NULL, xprt_timer);
609         __xprt_release_write(xprt, task);
610         spin_unlock_bh(&xprt->transport_lock);
611 }
612
613 static inline void do_xprt_reserve(struct rpc_task *task)
614 {
615         struct rpc_xprt *xprt = task->tk_xprt;
616
617         task->tk_status = 0;
618         if (task->tk_rqstp)
619                 return;
620         if (!list_empty(&xprt->free)) {
621                 struct rpc_rqst *req = list_entry(xprt->free.next, struct rpc_rqst, rq_list);
622                 list_del_init(&req->rq_list);
623                 task->tk_rqstp = req;
624                 xprt_request_init(task, xprt);
625                 return;
626         }
627         dprintk("RPC:      waiting for request slot\n");
628         task->tk_status = -EAGAIN;
629         task->tk_timeout = 0;
630         rpc_sleep_on(&xprt->backlog, task, NULL, NULL);
631 }
632
633 /**
634  * xprt_reserve - allocate an RPC request slot
635  * @task: RPC task requesting a slot allocation
636  *
637  * If no more slots are available, place the task on the transport's
638  * backlog queue.
639  */
640 void xprt_reserve(struct rpc_task *task)
641 {
642         struct rpc_xprt *xprt = task->tk_xprt;
643
644         task->tk_status = -EIO;
645         if (!xprt->shutdown) {
646                 spin_lock(&xprt->reserve_lock);
647                 do_xprt_reserve(task);
648                 spin_unlock(&xprt->reserve_lock);
649         }
650 }
651
652 static inline u32 xprt_alloc_xid(struct rpc_xprt *xprt)
653 {
654         return xprt->xid++;
655 }
656
657 static inline void xprt_init_xid(struct rpc_xprt *xprt)
658 {
659         get_random_bytes(&xprt->xid, sizeof(xprt->xid));
660 }
661
662 static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt)
663 {
664         struct rpc_rqst *req = task->tk_rqstp;
665
666         req->rq_timeout = xprt->timeout.to_initval;
667         req->rq_task    = task;
668         req->rq_xprt    = xprt;
669         req->rq_xid     = xprt_alloc_xid(xprt);
670         dprintk("RPC: %4d reserved req %p xid %08x\n", task->tk_pid,
671                         req, ntohl(req->rq_xid));
672 }
673
674 /**
675  * xprt_release - release an RPC request slot
676  * @task: task which is finished with the slot
677  *
678  */
679 void xprt_release(struct rpc_task *task)
680 {
681         struct rpc_xprt *xprt = task->tk_xprt;
682         struct rpc_rqst *req;
683
684         if (!(req = task->tk_rqstp))
685                 return;
686         spin_lock_bh(&xprt->transport_lock);
687         __xprt_release_write(xprt, task);
688         __xprt_put_cong(xprt, req);
689         if (!list_empty(&req->rq_list))
690                 list_del(&req->rq_list);
691         xprt->last_used = jiffies;
692         if (list_empty(&xprt->recv) && !xprt->shutdown)
693                 mod_timer(&xprt->timer,
694                                 xprt->last_used + RPC_IDLE_DISCONNECT_TIMEOUT);
695         spin_unlock_bh(&xprt->transport_lock);
696         task->tk_rqstp = NULL;
697         memset(req, 0, sizeof(*req));   /* mark unused */
698
699         dprintk("RPC: %4d release request %p\n", task->tk_pid, req);
700
701         spin_lock(&xprt->reserve_lock);
702         list_add(&req->rq_list, &xprt->free);
703         xprt_clear_backlog(xprt);
704         spin_unlock(&xprt->reserve_lock);
705 }
706
707 /**
708  * xprt_set_timeout - set constant RPC timeout
709  * @to: RPC timeout parameters to set up
710  * @retr: number of retries
711  * @incr: amount of increase after each retry
712  *
713  */
714 void xprt_set_timeout(struct rpc_timeout *to, unsigned int retr, unsigned long incr)
715 {
716         to->to_initval   = 
717         to->to_increment = incr;
718         to->to_maxval    = to->to_initval + (incr * retr);
719         to->to_retries   = retr;
720         to->to_exponential = 0;
721 }
722
723 static struct rpc_xprt *xprt_setup(int proto, struct sockaddr_in *ap, struct rpc_timeout *to)
724 {
725         int result;
726         struct rpc_xprt *xprt;
727         struct rpc_rqst *req;
728
729         if ((xprt = kmalloc(sizeof(struct rpc_xprt), GFP_KERNEL)) == NULL)
730                 return ERR_PTR(-ENOMEM);
731         memset(xprt, 0, sizeof(*xprt)); /* Nnnngh! */
732
733         xprt->addr = *ap;
734
735         switch (proto) {
736         case IPPROTO_UDP:
737                 result = xs_setup_udp(xprt, to);
738                 break;
739         case IPPROTO_TCP:
740                 result = xs_setup_tcp(xprt, to);
741                 break;
742         default:
743                 printk(KERN_ERR "RPC: unrecognized transport protocol: %d\n",
744                                 proto);
745                 result = -EIO;
746                 break;
747         }
748         if (result) {
749                 kfree(xprt);
750                 return ERR_PTR(result);
751         }
752
753         spin_lock_init(&xprt->transport_lock);
754         spin_lock_init(&xprt->reserve_lock);
755         init_waitqueue_head(&xprt->cong_wait);
756
757         INIT_LIST_HEAD(&xprt->free);
758         INIT_LIST_HEAD(&xprt->recv);
759         INIT_WORK(&xprt->task_cleanup, xprt_socket_autoclose, xprt);
760         init_timer(&xprt->timer);
761         xprt->timer.function = xprt_init_autodisconnect;
762         xprt->timer.data = (unsigned long) xprt;
763         xprt->last_used = jiffies;
764
765         rpc_init_wait_queue(&xprt->pending, "xprt_pending");
766         rpc_init_wait_queue(&xprt->sending, "xprt_sending");
767         rpc_init_wait_queue(&xprt->resend, "xprt_resend");
768         rpc_init_priority_wait_queue(&xprt->backlog, "xprt_backlog");
769
770         /* initialize free list */
771         for (req = &xprt->slot[xprt->max_reqs-1]; req >= &xprt->slot[0]; req--)
772                 list_add(&req->rq_list, &xprt->free);
773
774         xprt_init_xid(xprt);
775
776         dprintk("RPC:      created transport %p with %u slots\n", xprt,
777                         xprt->max_reqs);
778         
779         return xprt;
780 }
781
782 /**
783  * xprt_create_proto - create an RPC client transport
784  * @proto: requested transport protocol
785  * @sap: remote peer's address
786  * @to: timeout parameters for new transport
787  *
788  */
789 struct rpc_xprt *xprt_create_proto(int proto, struct sockaddr_in *sap, struct rpc_timeout *to)
790 {
791         struct rpc_xprt *xprt;
792
793         xprt = xprt_setup(proto, sap, to);
794         if (IS_ERR(xprt))
795                 dprintk("RPC:      xprt_create_proto failed\n");
796         else
797                 dprintk("RPC:      xprt_create_proto created xprt %p\n", xprt);
798         return xprt;
799 }
800
801 static void xprt_shutdown(struct rpc_xprt *xprt)
802 {
803         xprt->shutdown = 1;
804         rpc_wake_up(&xprt->sending);
805         rpc_wake_up(&xprt->resend);
806         rpc_wake_up(&xprt->pending);
807         rpc_wake_up(&xprt->backlog);
808         wake_up(&xprt->cong_wait);
809         del_timer_sync(&xprt->timer);
810 }
811
812 static int xprt_clear_backlog(struct rpc_xprt *xprt) {
813         rpc_wake_up_next(&xprt->backlog);
814         wake_up(&xprt->cong_wait);
815         return 1;
816 }
817
818 /**
819  * xprt_destroy - destroy an RPC transport, killing off all requests.
820  * @xprt: transport to destroy
821  *
822  */
823 int xprt_destroy(struct rpc_xprt *xprt)
824 {
825         dprintk("RPC:      destroying transport %p\n", xprt);
826         xprt_shutdown(xprt);
827         xprt->ops->destroy(xprt);
828         kfree(xprt);
829
830         return 0;
831 }