~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/net/sunrpc/xprt.c

Version: ~ [ linux-5.4-rc7 ] ~ [ linux-5.3.11 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.84 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.154 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.201 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.201 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.77 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  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, if a reply is expected,
 16  *      it installs a timer that is run after the packet's timeout has
 17  *      expired.
 18  *  -   When a packet arrives, the data_ready handler walks the list of
 19  *      pending requests for that transport. If a matching XID is found, the
 20  *      caller is woken up, and the timer removed.
 21  *  -   When no reply arrives within the timeout interval, the timer is
 22  *      fired by the kernel and runs xprt_timer(). It either adjusts the
 23  *      timeout values (minor timeout) or wakes up the caller with a status
 24  *      of -ETIMEDOUT.
 25  *  -   When the caller receives a notification from RPC that a reply arrived,
 26  *      it should release the RPC slot, and process the reply.
 27  *      If the call timed out, it may choose to retry the operation by
 28  *      adjusting the initial timeout value, and simply calling rpc_call
 29  *      again.
 30  *
 31  *  Support for async RPC is done through a set of RPC-specific scheduling
 32  *  primitives that `transparently' work for processes as well as async
 33  *  tasks that rely on callbacks.
 34  *
 35  *  Copyright (C) 1995-1997, Olaf Kirch <okir@monad.swb.de>
 36  *
 37  *  Transport switch API copyright (C) 2005, Chuck Lever <cel@netapp.com>
 38  */
 39 
 40 #include <linux/module.h>
 41 
 42 #include <linux/types.h>
 43 #include <linux/interrupt.h>
 44 #include <linux/workqueue.h>
 45 #include <linux/net.h>
 46 #include <linux/ktime.h>
 47 
 48 #include <linux/sunrpc/clnt.h>
 49 #include <linux/sunrpc/metrics.h>
 50 #include <linux/sunrpc/bc_xprt.h>
 51 #include <linux/rcupdate.h>
 52 
 53 #include <trace/events/sunrpc.h>
 54 
 55 #include "sunrpc.h"
 56 
 57 /*
 58  * Local variables
 59  */
 60 
 61 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 62 # define RPCDBG_FACILITY        RPCDBG_XPRT
 63 #endif
 64 
 65 /*
 66  * Local functions
 67  */
 68 static void      xprt_init(struct rpc_xprt *xprt, struct net *net);
 69 static void     xprt_request_init(struct rpc_task *, struct rpc_xprt *);
 70 static void     xprt_connect_status(struct rpc_task *task);
 71 static int      __xprt_get_cong(struct rpc_xprt *, struct rpc_task *);
 72 static void     __xprt_put_cong(struct rpc_xprt *, struct rpc_rqst *);
 73 static void      xprt_destroy(struct rpc_xprt *xprt);
 74 
 75 static DEFINE_SPINLOCK(xprt_list_lock);
 76 static LIST_HEAD(xprt_list);
 77 
 78 /**
 79  * xprt_register_transport - register a transport implementation
 80  * @transport: transport to register
 81  *
 82  * If a transport implementation is loaded as a kernel module, it can
 83  * call this interface to make itself known to the RPC client.
 84  *
 85  * Returns:
 86  * 0:           transport successfully registered
 87  * -EEXIST:     transport already registered
 88  * -EINVAL:     transport module being unloaded
 89  */
 90 int xprt_register_transport(struct xprt_class *transport)
 91 {
 92         struct xprt_class *t;
 93         int result;
 94 
 95         result = -EEXIST;
 96         spin_lock(&xprt_list_lock);
 97         list_for_each_entry(t, &xprt_list, list) {
 98                 /* don't register the same transport class twice */
 99                 if (t->ident == transport->ident)
100                         goto out;
101         }
102 
103         list_add_tail(&transport->list, &xprt_list);
104         printk(KERN_INFO "RPC: Registered %s transport module.\n",
105                transport->name);
106         result = 0;
107 
108 out:
109         spin_unlock(&xprt_list_lock);
110         return result;
111 }
112 EXPORT_SYMBOL_GPL(xprt_register_transport);
113 
114 /**
115  * xprt_unregister_transport - unregister a transport implementation
116  * @transport: transport to unregister
117  *
118  * Returns:
119  * 0:           transport successfully unregistered
120  * -ENOENT:     transport never registered
121  */
122 int xprt_unregister_transport(struct xprt_class *transport)
123 {
124         struct xprt_class *t;
125         int result;
126 
127         result = 0;
128         spin_lock(&xprt_list_lock);
129         list_for_each_entry(t, &xprt_list, list) {
130                 if (t == transport) {
131                         printk(KERN_INFO
132                                 "RPC: Unregistered %s transport module.\n",
133                                 transport->name);
134                         list_del_init(&transport->list);
135                         goto out;
136                 }
137         }
138         result = -ENOENT;
139 
140 out:
141         spin_unlock(&xprt_list_lock);
142         return result;
143 }
144 EXPORT_SYMBOL_GPL(xprt_unregister_transport);
145 
146 /**
147  * xprt_load_transport - load a transport implementation
148  * @transport_name: transport to load
149  *
150  * Returns:
151  * 0:           transport successfully loaded
152  * -ENOENT:     transport module not available
153  */
154 int xprt_load_transport(const char *transport_name)
155 {
156         struct xprt_class *t;
157         int result;
158 
159         result = 0;
160         spin_lock(&xprt_list_lock);
161         list_for_each_entry(t, &xprt_list, list) {
162                 if (strcmp(t->name, transport_name) == 0) {
163                         spin_unlock(&xprt_list_lock);
164                         goto out;
165                 }
166         }
167         spin_unlock(&xprt_list_lock);
168         result = request_module("xprt%s", transport_name);
169 out:
170         return result;
171 }
172 EXPORT_SYMBOL_GPL(xprt_load_transport);
173 
174 /**
175  * xprt_reserve_xprt - serialize write access to transports
176  * @task: task that is requesting access to the transport
177  * @xprt: pointer to the target transport
178  *
179  * This prevents mixing the payload of separate requests, and prevents
180  * transport connects from colliding with writes.  No congestion control
181  * is provided.
182  */
183 int xprt_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
184 {
185         struct rpc_rqst *req = task->tk_rqstp;
186         int priority;
187 
188         if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
189                 if (task == xprt->snd_task)
190                         return 1;
191                 goto out_sleep;
192         }
193         xprt->snd_task = task;
194         if (req != NULL)
195                 req->rq_ntrans++;
196 
197         return 1;
198 
199 out_sleep:
200         dprintk("RPC: %5u failed to lock transport %p\n",
201                         task->tk_pid, xprt);
202         task->tk_timeout = 0;
203         task->tk_status = -EAGAIN;
204         if (req == NULL)
205                 priority = RPC_PRIORITY_LOW;
206         else if (!req->rq_ntrans)
207                 priority = RPC_PRIORITY_NORMAL;
208         else
209                 priority = RPC_PRIORITY_HIGH;
210         rpc_sleep_on_priority(&xprt->sending, task, NULL, priority);
211         return 0;
212 }
213 EXPORT_SYMBOL_GPL(xprt_reserve_xprt);
214 
215 static void xprt_clear_locked(struct rpc_xprt *xprt)
216 {
217         xprt->snd_task = NULL;
218         if (!test_bit(XPRT_CLOSE_WAIT, &xprt->state)) {
219                 smp_mb__before_atomic();
220                 clear_bit(XPRT_LOCKED, &xprt->state);
221                 smp_mb__after_atomic();
222         } else
223                 queue_work(xprtiod_workqueue, &xprt->task_cleanup);
224 }
225 
226 /*
227  * xprt_reserve_xprt_cong - serialize write access to transports
228  * @task: task that is requesting access to the transport
229  *
230  * Same as xprt_reserve_xprt, but Van Jacobson congestion control is
231  * integrated into the decision of whether a request is allowed to be
232  * woken up and given access to the transport.
233  */
234 int xprt_reserve_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task)
235 {
236         struct rpc_rqst *req = task->tk_rqstp;
237         int priority;
238 
239         if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
240                 if (task == xprt->snd_task)
241                         return 1;
242                 goto out_sleep;
243         }
244         if (req == NULL) {
245                 xprt->snd_task = task;
246                 return 1;
247         }
248         if (__xprt_get_cong(xprt, task)) {
249                 xprt->snd_task = task;
250                 req->rq_ntrans++;
251                 return 1;
252         }
253         xprt_clear_locked(xprt);
254 out_sleep:
255         if (req)
256                 __xprt_put_cong(xprt, req);
257         dprintk("RPC: %5u failed to lock transport %p\n", task->tk_pid, xprt);
258         task->tk_timeout = 0;
259         task->tk_status = -EAGAIN;
260         if (req == NULL)
261                 priority = RPC_PRIORITY_LOW;
262         else if (!req->rq_ntrans)
263                 priority = RPC_PRIORITY_NORMAL;
264         else
265                 priority = RPC_PRIORITY_HIGH;
266         rpc_sleep_on_priority(&xprt->sending, task, NULL, priority);
267         return 0;
268 }
269 EXPORT_SYMBOL_GPL(xprt_reserve_xprt_cong);
270 
271 static inline int xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task)
272 {
273         int retval;
274 
275         spin_lock_bh(&xprt->transport_lock);
276         retval = xprt->ops->reserve_xprt(xprt, task);
277         spin_unlock_bh(&xprt->transport_lock);
278         return retval;
279 }
280 
281 static bool __xprt_lock_write_func(struct rpc_task *task, void *data)
282 {
283         struct rpc_xprt *xprt = data;
284         struct rpc_rqst *req;
285 
286         req = task->tk_rqstp;
287         xprt->snd_task = task;
288         if (req)
289                 req->rq_ntrans++;
290         return true;
291 }
292 
293 static void __xprt_lock_write_next(struct rpc_xprt *xprt)
294 {
295         if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
296                 return;
297 
298         if (rpc_wake_up_first_on_wq(xprtiod_workqueue, &xprt->sending,
299                                 __xprt_lock_write_func, xprt))
300                 return;
301         xprt_clear_locked(xprt);
302 }
303 
304 static bool __xprt_lock_write_cong_func(struct rpc_task *task, void *data)
305 {
306         struct rpc_xprt *xprt = data;
307         struct rpc_rqst *req;
308 
309         req = task->tk_rqstp;
310         if (req == NULL) {
311                 xprt->snd_task = task;
312                 return true;
313         }
314         if (__xprt_get_cong(xprt, task)) {
315                 xprt->snd_task = task;
316                 req->rq_ntrans++;
317                 return true;
318         }
319         return false;
320 }
321 
322 static void __xprt_lock_write_next_cong(struct rpc_xprt *xprt)
323 {
324         if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
325                 return;
326         if (RPCXPRT_CONGESTED(xprt))
327                 goto out_unlock;
328         if (rpc_wake_up_first_on_wq(xprtiod_workqueue, &xprt->sending,
329                                 __xprt_lock_write_cong_func, xprt))
330                 return;
331 out_unlock:
332         xprt_clear_locked(xprt);
333 }
334 
335 static void xprt_task_clear_bytes_sent(struct rpc_task *task)
336 {
337         if (task != NULL) {
338                 struct rpc_rqst *req = task->tk_rqstp;
339                 if (req != NULL)
340                         req->rq_bytes_sent = 0;
341         }
342 }
343 
344 /**
345  * xprt_release_xprt - allow other requests to use a transport
346  * @xprt: transport with other tasks potentially waiting
347  * @task: task that is releasing access to the transport
348  *
349  * Note that "task" can be NULL.  No congestion control is provided.
350  */
351 void xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
352 {
353         if (xprt->snd_task == task) {
354                 xprt_task_clear_bytes_sent(task);
355                 xprt_clear_locked(xprt);
356                 __xprt_lock_write_next(xprt);
357         }
358 }
359 EXPORT_SYMBOL_GPL(xprt_release_xprt);
360 
361 /**
362  * xprt_release_xprt_cong - allow other requests to use a transport
363  * @xprt: transport with other tasks potentially waiting
364  * @task: task that is releasing access to the transport
365  *
366  * Note that "task" can be NULL.  Another task is awoken to use the
367  * transport if the transport's congestion window allows it.
368  */
369 void xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task)
370 {
371         if (xprt->snd_task == task) {
372                 xprt_task_clear_bytes_sent(task);
373                 xprt_clear_locked(xprt);
374                 __xprt_lock_write_next_cong(xprt);
375         }
376 }
377 EXPORT_SYMBOL_GPL(xprt_release_xprt_cong);
378 
379 static inline void xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task)
380 {
381         spin_lock_bh(&xprt->transport_lock);
382         xprt->ops->release_xprt(xprt, task);
383         spin_unlock_bh(&xprt->transport_lock);
384 }
385 
386 /*
387  * Van Jacobson congestion avoidance. Check if the congestion window
388  * overflowed. Put the task to sleep if this is the case.
389  */
390 static int
391 __xprt_get_cong(struct rpc_xprt *xprt, struct rpc_task *task)
392 {
393         struct rpc_rqst *req = task->tk_rqstp;
394 
395         if (req->rq_cong)
396                 return 1;
397         dprintk("RPC: %5u xprt_cwnd_limited cong = %lu cwnd = %lu\n",
398                         task->tk_pid, xprt->cong, xprt->cwnd);
399         if (RPCXPRT_CONGESTED(xprt))
400                 return 0;
401         req->rq_cong = 1;
402         xprt->cong += RPC_CWNDSCALE;
403         return 1;
404 }
405 
406 /*
407  * Adjust the congestion window, and wake up the next task
408  * that has been sleeping due to congestion
409  */
410 static void
411 __xprt_put_cong(struct rpc_xprt *xprt, struct rpc_rqst *req)
412 {
413         if (!req->rq_cong)
414                 return;
415         req->rq_cong = 0;
416         xprt->cong -= RPC_CWNDSCALE;
417         __xprt_lock_write_next_cong(xprt);
418 }
419 
420 /**
421  * xprt_release_rqst_cong - housekeeping when request is complete
422  * @task: RPC request that recently completed
423  *
424  * Useful for transports that require congestion control.
425  */
426 void xprt_release_rqst_cong(struct rpc_task *task)
427 {
428         struct rpc_rqst *req = task->tk_rqstp;
429 
430         __xprt_put_cong(req->rq_xprt, req);
431 }
432 EXPORT_SYMBOL_GPL(xprt_release_rqst_cong);
433 
434 /**
435  * xprt_adjust_cwnd - adjust transport congestion window
436  * @xprt: pointer to xprt
437  * @task: recently completed RPC request used to adjust window
438  * @result: result code of completed RPC request
439  *
440  * The transport code maintains an estimate on the maximum number of out-
441  * standing RPC requests, using a smoothed version of the congestion
442  * avoidance implemented in 44BSD. This is basically the Van Jacobson
443  * congestion algorithm: If a retransmit occurs, the congestion window is
444  * halved; otherwise, it is incremented by 1/cwnd when
445  *
446  *      -       a reply is received and
447  *      -       a full number of requests are outstanding and
448  *      -       the congestion window hasn't been updated recently.
449  */
450 void xprt_adjust_cwnd(struct rpc_xprt *xprt, struct rpc_task *task, int result)
451 {
452         struct rpc_rqst *req = task->tk_rqstp;
453         unsigned long cwnd = xprt->cwnd;
454 
455         if (result >= 0 && cwnd <= xprt->cong) {
456                 /* The (cwnd >> 1) term makes sure
457                  * the result gets rounded properly. */
458                 cwnd += (RPC_CWNDSCALE * RPC_CWNDSCALE + (cwnd >> 1)) / cwnd;
459                 if (cwnd > RPC_MAXCWND(xprt))
460                         cwnd = RPC_MAXCWND(xprt);
461                 __xprt_lock_write_next_cong(xprt);
462         } else if (result == -ETIMEDOUT) {
463                 cwnd >>= 1;
464                 if (cwnd < RPC_CWNDSCALE)
465                         cwnd = RPC_CWNDSCALE;
466         }
467         dprintk("RPC:       cong %ld, cwnd was %ld, now %ld\n",
468                         xprt->cong, xprt->cwnd, cwnd);
469         xprt->cwnd = cwnd;
470         __xprt_put_cong(xprt, req);
471 }
472 EXPORT_SYMBOL_GPL(xprt_adjust_cwnd);
473 
474 /**
475  * xprt_wake_pending_tasks - wake all tasks on a transport's pending queue
476  * @xprt: transport with waiting tasks
477  * @status: result code to plant in each task before waking it
478  *
479  */
480 void xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status)
481 {
482         if (status < 0)
483                 rpc_wake_up_status(&xprt->pending, status);
484         else
485                 rpc_wake_up(&xprt->pending);
486 }
487 EXPORT_SYMBOL_GPL(xprt_wake_pending_tasks);
488 
489 /**
490  * xprt_wait_for_buffer_space - wait for transport output buffer to clear
491  * @task: task to be put to sleep
492  * @action: function pointer to be executed after wait
493  *
494  * Note that we only set the timer for the case of RPC_IS_SOFT(), since
495  * we don't in general want to force a socket disconnection due to
496  * an incomplete RPC call transmission.
497  */
498 void xprt_wait_for_buffer_space(struct rpc_task *task, rpc_action action)
499 {
500         struct rpc_rqst *req = task->tk_rqstp;
501         struct rpc_xprt *xprt = req->rq_xprt;
502 
503         task->tk_timeout = RPC_IS_SOFT(task) ? req->rq_timeout : 0;
504         rpc_sleep_on(&xprt->pending, task, action);
505 }
506 EXPORT_SYMBOL_GPL(xprt_wait_for_buffer_space);
507 
508 /**
509  * xprt_write_space - wake the task waiting for transport output buffer space
510  * @xprt: transport with waiting tasks
511  *
512  * Can be called in a soft IRQ context, so xprt_write_space never sleeps.
513  */
514 void xprt_write_space(struct rpc_xprt *xprt)
515 {
516         spin_lock_bh(&xprt->transport_lock);
517         if (xprt->snd_task) {
518                 dprintk("RPC:       write space: waking waiting task on "
519                                 "xprt %p\n", xprt);
520                 rpc_wake_up_queued_task(&xprt->pending, xprt->snd_task);
521         }
522         spin_unlock_bh(&xprt->transport_lock);
523 }
524 EXPORT_SYMBOL_GPL(xprt_write_space);
525 
526 /**
527  * xprt_set_retrans_timeout_def - set a request's retransmit timeout
528  * @task: task whose timeout is to be set
529  *
530  * Set a request's retransmit timeout based on the transport's
531  * default timeout parameters.  Used by transports that don't adjust
532  * the retransmit timeout based on round-trip time estimation.
533  */
534 void xprt_set_retrans_timeout_def(struct rpc_task *task)
535 {
536         task->tk_timeout = task->tk_rqstp->rq_timeout;
537 }
538 EXPORT_SYMBOL_GPL(xprt_set_retrans_timeout_def);
539 
540 /**
541  * xprt_set_retrans_timeout_rtt - set a request's retransmit timeout
542  * @task: task whose timeout is to be set
543  *
544  * Set a request's retransmit timeout using the RTT estimator.
545  */
546 void xprt_set_retrans_timeout_rtt(struct rpc_task *task)
547 {
548         int timer = task->tk_msg.rpc_proc->p_timer;
549         struct rpc_clnt *clnt = task->tk_client;
550         struct rpc_rtt *rtt = clnt->cl_rtt;
551         struct rpc_rqst *req = task->tk_rqstp;
552         unsigned long max_timeout = clnt->cl_timeout->to_maxval;
553 
554         task->tk_timeout = rpc_calc_rto(rtt, timer);
555         task->tk_timeout <<= rpc_ntimeo(rtt, timer) + req->rq_retries;
556         if (task->tk_timeout > max_timeout || task->tk_timeout == 0)
557                 task->tk_timeout = max_timeout;
558 }
559 EXPORT_SYMBOL_GPL(xprt_set_retrans_timeout_rtt);
560 
561 static void xprt_reset_majortimeo(struct rpc_rqst *req)
562 {
563         const struct rpc_timeout *to = req->rq_task->tk_client->cl_timeout;
564 
565         req->rq_majortimeo = req->rq_timeout;
566         if (to->to_exponential)
567                 req->rq_majortimeo <<= to->to_retries;
568         else
569                 req->rq_majortimeo += to->to_increment * to->to_retries;
570         if (req->rq_majortimeo > to->to_maxval || req->rq_majortimeo == 0)
571                 req->rq_majortimeo = to->to_maxval;
572         req->rq_majortimeo += jiffies;
573 }
574 
575 /**
576  * xprt_adjust_timeout - adjust timeout values for next retransmit
577  * @req: RPC request containing parameters to use for the adjustment
578  *
579  */
580 int xprt_adjust_timeout(struct rpc_rqst *req)
581 {
582         struct rpc_xprt *xprt = req->rq_xprt;
583         const struct rpc_timeout *to = req->rq_task->tk_client->cl_timeout;
584         int status = 0;
585 
586         if (time_before(jiffies, req->rq_majortimeo)) {
587                 if (to->to_exponential)
588                         req->rq_timeout <<= 1;
589                 else
590                         req->rq_timeout += to->to_increment;
591                 if (to->to_maxval && req->rq_timeout >= to->to_maxval)
592                         req->rq_timeout = to->to_maxval;
593                 req->rq_retries++;
594         } else {
595                 req->rq_timeout = to->to_initval;
596                 req->rq_retries = 0;
597                 xprt_reset_majortimeo(req);
598                 /* Reset the RTT counters == "slow start" */
599                 spin_lock_bh(&xprt->transport_lock);
600                 rpc_init_rtt(req->rq_task->tk_client->cl_rtt, to->to_initval);
601                 spin_unlock_bh(&xprt->transport_lock);
602                 status = -ETIMEDOUT;
603         }
604 
605         if (req->rq_timeout == 0) {
606                 printk(KERN_WARNING "xprt_adjust_timeout: rq_timeout = 0!\n");
607                 req->rq_timeout = 5 * HZ;
608         }
609         return status;
610 }
611 
612 static void xprt_autoclose(struct work_struct *work)
613 {
614         struct rpc_xprt *xprt =
615                 container_of(work, struct rpc_xprt, task_cleanup);
616 
617         clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
618         xprt->ops->close(xprt);
619         xprt_release_write(xprt, NULL);
620         wake_up_bit(&xprt->state, XPRT_LOCKED);
621 }
622 
623 /**
624  * xprt_disconnect_done - mark a transport as disconnected
625  * @xprt: transport to flag for disconnect
626  *
627  */
628 void xprt_disconnect_done(struct rpc_xprt *xprt)
629 {
630         dprintk("RPC:       disconnected transport %p\n", xprt);
631         spin_lock_bh(&xprt->transport_lock);
632         xprt_clear_connected(xprt);
633         xprt_wake_pending_tasks(xprt, -EAGAIN);
634         spin_unlock_bh(&xprt->transport_lock);
635 }
636 EXPORT_SYMBOL_GPL(xprt_disconnect_done);
637 
638 /**
639  * xprt_force_disconnect - force a transport to disconnect
640  * @xprt: transport to disconnect
641  *
642  */
643 void xprt_force_disconnect(struct rpc_xprt *xprt)
644 {
645         /* Don't race with the test_bit() in xprt_clear_locked() */
646         spin_lock_bh(&xprt->transport_lock);
647         set_bit(XPRT_CLOSE_WAIT, &xprt->state);
648         /* Try to schedule an autoclose RPC call */
649         if (test_and_set_bit(XPRT_LOCKED, &xprt->state) == 0)
650                 queue_work(xprtiod_workqueue, &xprt->task_cleanup);
651         xprt_wake_pending_tasks(xprt, -EAGAIN);
652         spin_unlock_bh(&xprt->transport_lock);
653 }
654 EXPORT_SYMBOL_GPL(xprt_force_disconnect);
655 
656 /**
657  * xprt_conditional_disconnect - force a transport to disconnect
658  * @xprt: transport to disconnect
659  * @cookie: 'connection cookie'
660  *
661  * This attempts to break the connection if and only if 'cookie' matches
662  * the current transport 'connection cookie'. It ensures that we don't
663  * try to break the connection more than once when we need to retransmit
664  * a batch of RPC requests.
665  *
666  */
667 void xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie)
668 {
669         /* Don't race with the test_bit() in xprt_clear_locked() */
670         spin_lock_bh(&xprt->transport_lock);
671         if (cookie != xprt->connect_cookie)
672                 goto out;
673         if (test_bit(XPRT_CLOSING, &xprt->state))
674                 goto out;
675         set_bit(XPRT_CLOSE_WAIT, &xprt->state);
676         /* Try to schedule an autoclose RPC call */
677         if (test_and_set_bit(XPRT_LOCKED, &xprt->state) == 0)
678                 queue_work(xprtiod_workqueue, &xprt->task_cleanup);
679         xprt_wake_pending_tasks(xprt, -EAGAIN);
680 out:
681         spin_unlock_bh(&xprt->transport_lock);
682 }
683 
684 static bool
685 xprt_has_timer(const struct rpc_xprt *xprt)
686 {
687         return xprt->idle_timeout != 0;
688 }
689 
690 static void
691 xprt_schedule_autodisconnect(struct rpc_xprt *xprt)
692         __must_hold(&xprt->transport_lock)
693 {
694         if (list_empty(&xprt->recv) && xprt_has_timer(xprt))
695                 mod_timer(&xprt->timer, xprt->last_used + xprt->idle_timeout);
696 }
697 
698 static void
699 xprt_init_autodisconnect(unsigned long data)
700 {
701         struct rpc_xprt *xprt = (struct rpc_xprt *)data;
702 
703         spin_lock(&xprt->transport_lock);
704         if (!list_empty(&xprt->recv))
705                 goto out_abort;
706         /* Reset xprt->last_used to avoid connect/autodisconnect cycling */
707         xprt->last_used = jiffies;
708         if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
709                 goto out_abort;
710         spin_unlock(&xprt->transport_lock);
711         queue_work(xprtiod_workqueue, &xprt->task_cleanup);
712         return;
713 out_abort:
714         spin_unlock(&xprt->transport_lock);
715 }
716 
717 bool xprt_lock_connect(struct rpc_xprt *xprt,
718                 struct rpc_task *task,
719                 void *cookie)
720 {
721         bool ret = false;
722 
723         spin_lock_bh(&xprt->transport_lock);
724         if (!test_bit(XPRT_LOCKED, &xprt->state))
725                 goto out;
726         if (xprt->snd_task != task)
727                 goto out;
728         xprt_task_clear_bytes_sent(task);
729         xprt->snd_task = cookie;
730         ret = true;
731 out:
732         spin_unlock_bh(&xprt->transport_lock);
733         return ret;
734 }
735 
736 void xprt_unlock_connect(struct rpc_xprt *xprt, void *cookie)
737 {
738         spin_lock_bh(&xprt->transport_lock);
739         if (xprt->snd_task != cookie)
740                 goto out;
741         if (!test_bit(XPRT_LOCKED, &xprt->state))
742                 goto out;
743         xprt->snd_task =NULL;
744         xprt->ops->release_xprt(xprt, NULL);
745         xprt_schedule_autodisconnect(xprt);
746 out:
747         spin_unlock_bh(&xprt->transport_lock);
748         wake_up_bit(&xprt->state, XPRT_LOCKED);
749 }
750 
751 /**
752  * xprt_connect - schedule a transport connect operation
753  * @task: RPC task that is requesting the connect
754  *
755  */
756 void xprt_connect(struct rpc_task *task)
757 {
758         struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
759 
760         dprintk("RPC: %5u xprt_connect xprt %p %s connected\n", task->tk_pid,
761                         xprt, (xprt_connected(xprt) ? "is" : "is not"));
762 
763         if (!xprt_bound(xprt)) {
764                 task->tk_status = -EAGAIN;
765                 return;
766         }
767         if (!xprt_lock_write(xprt, task))
768                 return;
769 
770         if (test_and_clear_bit(XPRT_CLOSE_WAIT, &xprt->state))
771                 xprt->ops->close(xprt);
772 
773         if (!xprt_connected(xprt)) {
774                 task->tk_rqstp->rq_bytes_sent = 0;
775                 task->tk_timeout = task->tk_rqstp->rq_timeout;
776                 task->tk_rqstp->rq_connect_cookie = xprt->connect_cookie;
777                 rpc_sleep_on(&xprt->pending, task, xprt_connect_status);
778 
779                 if (test_bit(XPRT_CLOSING, &xprt->state))
780                         return;
781                 if (xprt_test_and_set_connecting(xprt))
782                         return;
783                 xprt->stat.connect_start = jiffies;
784                 xprt->ops->connect(xprt, task);
785         }
786         xprt_release_write(xprt, task);
787 }
788 
789 static void xprt_connect_status(struct rpc_task *task)
790 {
791         struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
792 
793         if (task->tk_status == 0) {
794                 xprt->stat.connect_count++;
795                 xprt->stat.connect_time += (long)jiffies - xprt->stat.connect_start;
796                 dprintk("RPC: %5u xprt_connect_status: connection established\n",
797                                 task->tk_pid);
798                 return;
799         }
800 
801         switch (task->tk_status) {
802         case -ECONNREFUSED:
803         case -ECONNRESET:
804         case -ECONNABORTED:
805         case -ENETUNREACH:
806         case -EHOSTUNREACH:
807         case -EPIPE:
808         case -EAGAIN:
809                 dprintk("RPC: %5u xprt_connect_status: retrying\n", task->tk_pid);
810                 break;
811         case -ETIMEDOUT:
812                 dprintk("RPC: %5u xprt_connect_status: connect attempt timed "
813                                 "out\n", task->tk_pid);
814                 break;
815         default:
816                 dprintk("RPC: %5u xprt_connect_status: error %d connecting to "
817                                 "server %s\n", task->tk_pid, -task->tk_status,
818                                 xprt->servername);
819                 task->tk_status = -EIO;
820         }
821 }
822 
823 /**
824  * xprt_lookup_rqst - find an RPC request corresponding to an XID
825  * @xprt: transport on which the original request was transmitted
826  * @xid: RPC XID of incoming reply
827  *
828  */
829 struct rpc_rqst *xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid)
830 {
831         struct rpc_rqst *entry;
832 
833         list_for_each_entry(entry, &xprt->recv, rq_list)
834                 if (entry->rq_xid == xid) {
835                         trace_xprt_lookup_rqst(xprt, xid, 0);
836                         return entry;
837                 }
838 
839         dprintk("RPC:       xprt_lookup_rqst did not find xid %08x\n",
840                         ntohl(xid));
841         trace_xprt_lookup_rqst(xprt, xid, -ENOENT);
842         xprt->stat.bad_xids++;
843         return NULL;
844 }
845 EXPORT_SYMBOL_GPL(xprt_lookup_rqst);
846 
847 static void xprt_update_rtt(struct rpc_task *task)
848 {
849         struct rpc_rqst *req = task->tk_rqstp;
850         struct rpc_rtt *rtt = task->tk_client->cl_rtt;
851         unsigned int timer = task->tk_msg.rpc_proc->p_timer;
852         long m = usecs_to_jiffies(ktime_to_us(req->rq_rtt));
853 
854         if (timer) {
855                 if (req->rq_ntrans == 1)
856                         rpc_update_rtt(rtt, timer, m);
857                 rpc_set_timeo(rtt, timer, req->rq_ntrans - 1);
858         }
859 }
860 
861 /**
862  * xprt_complete_rqst - called when reply processing is complete
863  * @task: RPC request that recently completed
864  * @copied: actual number of bytes received from the transport
865  *
866  * Caller holds transport lock.
867  */
868 void xprt_complete_rqst(struct rpc_task *task, int copied)
869 {
870         struct rpc_rqst *req = task->tk_rqstp;
871         struct rpc_xprt *xprt = req->rq_xprt;
872 
873         dprintk("RPC: %5u xid %08x complete (%d bytes received)\n",
874                         task->tk_pid, ntohl(req->rq_xid), copied);
875         trace_xprt_complete_rqst(xprt, req->rq_xid, copied);
876 
877         xprt->stat.recvs++;
878         req->rq_rtt = ktime_sub(ktime_get(), req->rq_xtime);
879         if (xprt->ops->timer != NULL)
880                 xprt_update_rtt(task);
881 
882         list_del_init(&req->rq_list);
883         req->rq_private_buf.len = copied;
884         /* Ensure all writes are done before we update */
885         /* req->rq_reply_bytes_recvd */
886         smp_wmb();
887         req->rq_reply_bytes_recvd = copied;
888         rpc_wake_up_queued_task(&xprt->pending, task);
889 }
890 EXPORT_SYMBOL_GPL(xprt_complete_rqst);
891 
892 static void xprt_timer(struct rpc_task *task)
893 {
894         struct rpc_rqst *req = task->tk_rqstp;
895         struct rpc_xprt *xprt = req->rq_xprt;
896 
897         if (task->tk_status != -ETIMEDOUT)
898                 return;
899         dprintk("RPC: %5u xprt_timer\n", task->tk_pid);
900 
901         if (!req->rq_reply_bytes_recvd) {
902                 if (xprt->ops->timer)
903                         xprt->ops->timer(xprt, task);
904         } else
905                 task->tk_status = 0;
906 }
907 
908 /**
909  * xprt_prepare_transmit - reserve the transport before sending a request
910  * @task: RPC task about to send a request
911  *
912  */
913 bool xprt_prepare_transmit(struct rpc_task *task)
914 {
915         struct rpc_rqst *req = task->tk_rqstp;
916         struct rpc_xprt *xprt = req->rq_xprt;
917         bool ret = false;
918 
919         dprintk("RPC: %5u xprt_prepare_transmit\n", task->tk_pid);
920 
921         spin_lock_bh(&xprt->transport_lock);
922         if (!req->rq_bytes_sent) {
923                 if (req->rq_reply_bytes_recvd) {
924                         task->tk_status = req->rq_reply_bytes_recvd;
925                         goto out_unlock;
926                 }
927                 if ((task->tk_flags & RPC_TASK_NO_RETRANS_TIMEOUT)
928                     && xprt_connected(xprt)
929                     && req->rq_connect_cookie == xprt->connect_cookie) {
930                         xprt->ops->set_retrans_timeout(task);
931                         rpc_sleep_on(&xprt->pending, task, xprt_timer);
932                         goto out_unlock;
933                 }
934         }
935         if (!xprt->ops->reserve_xprt(xprt, task)) {
936                 task->tk_status = -EAGAIN;
937                 goto out_unlock;
938         }
939         ret = true;
940 out_unlock:
941         spin_unlock_bh(&xprt->transport_lock);
942         return ret;
943 }
944 
945 void xprt_end_transmit(struct rpc_task *task)
946 {
947         xprt_release_write(task->tk_rqstp->rq_xprt, task);
948 }
949 
950 /**
951  * xprt_transmit - send an RPC request on a transport
952  * @task: controlling RPC task
953  *
954  * We have to copy the iovec because sendmsg fiddles with its contents.
955  */
956 void xprt_transmit(struct rpc_task *task)
957 {
958         struct rpc_rqst *req = task->tk_rqstp;
959         struct rpc_xprt *xprt = req->rq_xprt;
960         int status, numreqs;
961 
962         dprintk("RPC: %5u xprt_transmit(%u)\n", task->tk_pid, req->rq_slen);
963 
964         if (!req->rq_reply_bytes_recvd) {
965                 if (list_empty(&req->rq_list) && rpc_reply_expected(task)) {
966                         /*
967                          * Add to the list only if we're expecting a reply
968                          */
969                         spin_lock_bh(&xprt->transport_lock);
970                         /* Update the softirq receive buffer */
971                         memcpy(&req->rq_private_buf, &req->rq_rcv_buf,
972                                         sizeof(req->rq_private_buf));
973                         /* Add request to the receive list */
974                         list_add_tail(&req->rq_list, &xprt->recv);
975                         spin_unlock_bh(&xprt->transport_lock);
976                         xprt_reset_majortimeo(req);
977                         /* Turn off autodisconnect */
978                         del_singleshot_timer_sync(&xprt->timer);
979                 }
980         } else if (!req->rq_bytes_sent)
981                 return;
982 
983         req->rq_xtime = ktime_get();
984         status = xprt->ops->send_request(task);
985         trace_xprt_transmit(xprt, req->rq_xid, status);
986         if (status != 0) {
987                 task->tk_status = status;
988                 return;
989         }
990         xprt_inject_disconnect(xprt);
991 
992         dprintk("RPC: %5u xmit complete\n", task->tk_pid);
993         task->tk_flags |= RPC_TASK_SENT;
994         spin_lock_bh(&xprt->transport_lock);
995 
996         xprt->ops->set_retrans_timeout(task);
997 
998         numreqs = atomic_read(&xprt->num_reqs);
999         if (numreqs > xprt->stat.max_slots)
1000                 xprt->stat.max_slots = numreqs;
1001         xprt->stat.sends++;
1002         xprt->stat.req_u += xprt->stat.sends - xprt->stat.recvs;
1003         xprt->stat.bklog_u += xprt->backlog.qlen;
1004         xprt->stat.sending_u += xprt->sending.qlen;
1005         xprt->stat.pending_u += xprt->pending.qlen;
1006 
1007         /* Don't race with disconnect */
1008         if (!xprt_connected(xprt))
1009                 task->tk_status = -ENOTCONN;
1010         else {
1011                 /*
1012                  * Sleep on the pending queue since
1013                  * we're expecting a reply.
1014                  */
1015                 if (!req->rq_reply_bytes_recvd && rpc_reply_expected(task))
1016                         rpc_sleep_on(&xprt->pending, task, xprt_timer);
1017                 req->rq_connect_cookie = xprt->connect_cookie;
1018         }
1019         spin_unlock_bh(&xprt->transport_lock);
1020 }
1021 
1022 static void xprt_add_backlog(struct rpc_xprt *xprt, struct rpc_task *task)
1023 {
1024         set_bit(XPRT_CONGESTED, &xprt->state);
1025         rpc_sleep_on(&xprt->backlog, task, NULL);
1026 }
1027 
1028 static void xprt_wake_up_backlog(struct rpc_xprt *xprt)
1029 {
1030         if (rpc_wake_up_next(&xprt->backlog) == NULL)
1031                 clear_bit(XPRT_CONGESTED, &xprt->state);
1032 }
1033 
1034 static bool xprt_throttle_congested(struct rpc_xprt *xprt, struct rpc_task *task)
1035 {
1036         bool ret = false;
1037 
1038         if (!test_bit(XPRT_CONGESTED, &xprt->state))
1039                 goto out;
1040         spin_lock(&xprt->reserve_lock);
1041         if (test_bit(XPRT_CONGESTED, &xprt->state)) {
1042                 rpc_sleep_on(&xprt->backlog, task, NULL);
1043                 ret = true;
1044         }
1045         spin_unlock(&xprt->reserve_lock);
1046 out:
1047         return ret;
1048 }
1049 
1050 static struct rpc_rqst *xprt_dynamic_alloc_slot(struct rpc_xprt *xprt)
1051 {
1052         struct rpc_rqst *req = ERR_PTR(-EAGAIN);
1053 
1054         if (!atomic_add_unless(&xprt->num_reqs, 1, xprt->max_reqs))
1055                 goto out;
1056         spin_unlock(&xprt->reserve_lock);
1057         req = kzalloc(sizeof(struct rpc_rqst), GFP_NOFS);
1058         spin_lock(&xprt->reserve_lock);
1059         if (req != NULL)
1060                 goto out;
1061         atomic_dec(&xprt->num_reqs);
1062         req = ERR_PTR(-ENOMEM);
1063 out:
1064         return req;
1065 }
1066 
1067 static bool xprt_dynamic_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req)
1068 {
1069         if (atomic_add_unless(&xprt->num_reqs, -1, xprt->min_reqs)) {
1070                 kfree(req);
1071                 return true;
1072         }
1073         return false;
1074 }
1075 
1076 void xprt_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task)
1077 {
1078         struct rpc_rqst *req;
1079 
1080         spin_lock(&xprt->reserve_lock);
1081         if (!list_empty(&xprt->free)) {
1082                 req = list_entry(xprt->free.next, struct rpc_rqst, rq_list);
1083                 list_del(&req->rq_list);
1084                 goto out_init_req;
1085         }
1086         req = xprt_dynamic_alloc_slot(xprt);
1087         if (!IS_ERR(req))
1088                 goto out_init_req;
1089         switch (PTR_ERR(req)) {
1090         case -ENOMEM:
1091                 dprintk("RPC:       dynamic allocation of request slot "
1092                                 "failed! Retrying\n");
1093                 task->tk_status = -ENOMEM;
1094                 break;
1095         case -EAGAIN:
1096                 xprt_add_backlog(xprt, task);
1097                 dprintk("RPC:       waiting for request slot\n");
1098         default:
1099                 task->tk_status = -EAGAIN;
1100         }
1101         spin_unlock(&xprt->reserve_lock);
1102         return;
1103 out_init_req:
1104         task->tk_status = 0;
1105         task->tk_rqstp = req;
1106         xprt_request_init(task, xprt);
1107         spin_unlock(&xprt->reserve_lock);
1108 }
1109 EXPORT_SYMBOL_GPL(xprt_alloc_slot);
1110 
1111 void xprt_lock_and_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task)
1112 {
1113         /* Note: grabbing the xprt_lock_write() ensures that we throttle
1114          * new slot allocation if the transport is congested (i.e. when
1115          * reconnecting a stream transport or when out of socket write
1116          * buffer space).
1117          */
1118         if (xprt_lock_write(xprt, task)) {
1119                 xprt_alloc_slot(xprt, task);
1120                 xprt_release_write(xprt, task);
1121         }
1122 }
1123 EXPORT_SYMBOL_GPL(xprt_lock_and_alloc_slot);
1124 
1125 static void xprt_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req)
1126 {
1127         spin_lock(&xprt->reserve_lock);
1128         if (!xprt_dynamic_free_slot(xprt, req)) {
1129                 memset(req, 0, sizeof(*req));   /* mark unused */
1130                 list_add(&req->rq_list, &xprt->free);
1131         }
1132         xprt_wake_up_backlog(xprt);
1133         spin_unlock(&xprt->reserve_lock);
1134 }
1135 
1136 static void xprt_free_all_slots(struct rpc_xprt *xprt)
1137 {
1138         struct rpc_rqst *req;
1139         while (!list_empty(&xprt->free)) {
1140                 req = list_first_entry(&xprt->free, struct rpc_rqst, rq_list);
1141                 list_del(&req->rq_list);
1142                 kfree(req);
1143         }
1144 }
1145 
1146 struct rpc_xprt *xprt_alloc(struct net *net, size_t size,
1147                 unsigned int num_prealloc,
1148                 unsigned int max_alloc)
1149 {
1150         struct rpc_xprt *xprt;
1151         struct rpc_rqst *req;
1152         int i;
1153 
1154         xprt = kzalloc(size, GFP_KERNEL);
1155         if (xprt == NULL)
1156                 goto out;
1157 
1158         xprt_init(xprt, net);
1159 
1160         for (i = 0; i < num_prealloc; i++) {
1161                 req = kzalloc(sizeof(struct rpc_rqst), GFP_KERNEL);
1162                 if (!req)
1163                         goto out_free;
1164                 list_add(&req->rq_list, &xprt->free);
1165         }
1166         if (max_alloc > num_prealloc)
1167                 xprt->max_reqs = max_alloc;
1168         else
1169                 xprt->max_reqs = num_prealloc;
1170         xprt->min_reqs = num_prealloc;
1171         atomic_set(&xprt->num_reqs, num_prealloc);
1172 
1173         return xprt;
1174 
1175 out_free:
1176         xprt_free(xprt);
1177 out:
1178         return NULL;
1179 }
1180 EXPORT_SYMBOL_GPL(xprt_alloc);
1181 
1182 void xprt_free(struct rpc_xprt *xprt)
1183 {
1184         put_net(xprt->xprt_net);
1185         xprt_free_all_slots(xprt);
1186         kfree_rcu(xprt, rcu);
1187 }
1188 EXPORT_SYMBOL_GPL(xprt_free);
1189 
1190 /**
1191  * xprt_reserve - allocate an RPC request slot
1192  * @task: RPC task requesting a slot allocation
1193  *
1194  * If the transport is marked as being congested, or if no more
1195  * slots are available, place the task on the transport's
1196  * backlog queue.
1197  */
1198 void xprt_reserve(struct rpc_task *task)
1199 {
1200         struct rpc_xprt *xprt = task->tk_xprt;
1201 
1202         task->tk_status = 0;
1203         if (task->tk_rqstp != NULL)
1204                 return;
1205 
1206         task->tk_timeout = 0;
1207         task->tk_status = -EAGAIN;
1208         if (!xprt_throttle_congested(xprt, task))
1209                 xprt->ops->alloc_slot(xprt, task);
1210 }
1211 
1212 /**
1213  * xprt_retry_reserve - allocate an RPC request slot
1214  * @task: RPC task requesting a slot allocation
1215  *
1216  * If no more slots are available, place the task on the transport's
1217  * backlog queue.
1218  * Note that the only difference with xprt_reserve is that we now
1219  * ignore the value of the XPRT_CONGESTED flag.
1220  */
1221 void xprt_retry_reserve(struct rpc_task *task)
1222 {
1223         struct rpc_xprt *xprt = task->tk_xprt;
1224 
1225         task->tk_status = 0;
1226         if (task->tk_rqstp != NULL)
1227                 return;
1228 
1229         task->tk_timeout = 0;
1230         task->tk_status = -EAGAIN;
1231         xprt->ops->alloc_slot(xprt, task);
1232 }
1233 
1234 static inline __be32 xprt_alloc_xid(struct rpc_xprt *xprt)
1235 {
1236         return (__force __be32)xprt->xid++;
1237 }
1238 
1239 static inline void xprt_init_xid(struct rpc_xprt *xprt)
1240 {
1241         xprt->xid = prandom_u32();
1242 }
1243 
1244 static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt)
1245 {
1246         struct rpc_rqst *req = task->tk_rqstp;
1247 
1248         INIT_LIST_HEAD(&req->rq_list);
1249         req->rq_timeout = task->tk_client->cl_timeout->to_initval;
1250         req->rq_task    = task;
1251         req->rq_xprt    = xprt;
1252         req->rq_buffer  = NULL;
1253         req->rq_xid     = xprt_alloc_xid(xprt);
1254         req->rq_connect_cookie = xprt->connect_cookie - 1;
1255         req->rq_bytes_sent = 0;
1256         req->rq_snd_buf.len = 0;
1257         req->rq_snd_buf.buflen = 0;
1258         req->rq_rcv_buf.len = 0;
1259         req->rq_rcv_buf.buflen = 0;
1260         req->rq_release_snd_buf = NULL;
1261         xprt_reset_majortimeo(req);
1262         dprintk("RPC: %5u reserved req %p xid %08x\n", task->tk_pid,
1263                         req, ntohl(req->rq_xid));
1264 }
1265 
1266 /**
1267  * xprt_release - release an RPC request slot
1268  * @task: task which is finished with the slot
1269  *
1270  */
1271 void xprt_release(struct rpc_task *task)
1272 {
1273         struct rpc_xprt *xprt;
1274         struct rpc_rqst *req = task->tk_rqstp;
1275 
1276         if (req == NULL) {
1277                 if (task->tk_client) {
1278                         xprt = task->tk_xprt;
1279                         if (xprt->snd_task == task)
1280                                 xprt_release_write(xprt, task);
1281                 }
1282                 return;
1283         }
1284 
1285         xprt = req->rq_xprt;
1286         if (task->tk_ops->rpc_count_stats != NULL)
1287                 task->tk_ops->rpc_count_stats(task, task->tk_calldata);
1288         else if (task->tk_client)
1289                 rpc_count_iostats(task, task->tk_client->cl_metrics);
1290         spin_lock_bh(&xprt->transport_lock);
1291         xprt->ops->release_xprt(xprt, task);
1292         if (xprt->ops->release_request)
1293                 xprt->ops->release_request(task);
1294         if (!list_empty(&req->rq_list))
1295                 list_del(&req->rq_list);
1296         xprt->last_used = jiffies;
1297         xprt_schedule_autodisconnect(xprt);
1298         spin_unlock_bh(&xprt->transport_lock);
1299         if (req->rq_buffer)
1300                 xprt->ops->buf_free(task);
1301         xprt_inject_disconnect(xprt);
1302         if (req->rq_cred != NULL)
1303                 put_rpccred(req->rq_cred);
1304         task->tk_rqstp = NULL;
1305         if (req->rq_release_snd_buf)
1306                 req->rq_release_snd_buf(req);
1307 
1308         dprintk("RPC: %5u release request %p\n", task->tk_pid, req);
1309         if (likely(!bc_prealloc(req)))
1310                 xprt_free_slot(xprt, req);
1311         else
1312                 xprt_free_bc_request(req);
1313 }
1314 
1315 static void xprt_init(struct rpc_xprt *xprt, struct net *net)
1316 {
1317         kref_init(&xprt->kref);
1318 
1319         spin_lock_init(&xprt->transport_lock);
1320         spin_lock_init(&xprt->reserve_lock);
1321 
1322         INIT_LIST_HEAD(&xprt->free);
1323         INIT_LIST_HEAD(&xprt->recv);
1324 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1325         spin_lock_init(&xprt->bc_pa_lock);
1326         INIT_LIST_HEAD(&xprt->bc_pa_list);
1327 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1328         INIT_LIST_HEAD(&xprt->xprt_switch);
1329 
1330         xprt->last_used = jiffies;
1331         xprt->cwnd = RPC_INITCWND;
1332         xprt->bind_index = 0;
1333 
1334         rpc_init_wait_queue(&xprt->binding, "xprt_binding");
1335         rpc_init_wait_queue(&xprt->pending, "xprt_pending");
1336         rpc_init_priority_wait_queue(&xprt->sending, "xprt_sending");
1337         rpc_init_priority_wait_queue(&xprt->backlog, "xprt_backlog");
1338 
1339         xprt_init_xid(xprt);
1340 
1341         xprt->xprt_net = get_net(net);
1342 }
1343 
1344 /**
1345  * xprt_create_transport - create an RPC transport
1346  * @args: rpc transport creation arguments
1347  *
1348  */
1349 struct rpc_xprt *xprt_create_transport(struct xprt_create *args)
1350 {
1351         struct rpc_xprt *xprt;
1352         struct xprt_class *t;
1353 
1354         spin_lock(&xprt_list_lock);
1355         list_for_each_entry(t, &xprt_list, list) {
1356                 if (t->ident == args->ident) {
1357                         spin_unlock(&xprt_list_lock);
1358                         goto found;
1359                 }
1360         }
1361         spin_unlock(&xprt_list_lock);
1362         dprintk("RPC: transport (%d) not supported\n", args->ident);
1363         return ERR_PTR(-EIO);
1364 
1365 found:
1366         xprt = t->setup(args);
1367         if (IS_ERR(xprt)) {
1368                 dprintk("RPC:       xprt_create_transport: failed, %ld\n",
1369                                 -PTR_ERR(xprt));
1370                 goto out;
1371         }
1372         if (args->flags & XPRT_CREATE_NO_IDLE_TIMEOUT)
1373                 xprt->idle_timeout = 0;
1374         INIT_WORK(&xprt->task_cleanup, xprt_autoclose);
1375         if (xprt_has_timer(xprt))
1376                 setup_timer(&xprt->timer, xprt_init_autodisconnect,
1377                             (unsigned long)xprt);
1378         else
1379                 init_timer(&xprt->timer);
1380 
1381         if (strlen(args->servername) > RPC_MAXNETNAMELEN) {
1382                 xprt_destroy(xprt);
1383                 return ERR_PTR(-EINVAL);
1384         }
1385         xprt->servername = kstrdup(args->servername, GFP_KERNEL);
1386         if (xprt->servername == NULL) {
1387                 xprt_destroy(xprt);
1388                 return ERR_PTR(-ENOMEM);
1389         }
1390 
1391         rpc_xprt_debugfs_register(xprt);
1392 
1393         dprintk("RPC:       created transport %p with %u slots\n", xprt,
1394                         xprt->max_reqs);
1395 out:
1396         return xprt;
1397 }
1398 
1399 /**
1400  * xprt_destroy - destroy an RPC transport, killing off all requests.
1401  * @xprt: transport to destroy
1402  *
1403  */
1404 static void xprt_destroy(struct rpc_xprt *xprt)
1405 {
1406         dprintk("RPC:       destroying transport %p\n", xprt);
1407 
1408         /* Exclude transport connect/disconnect handlers */
1409         wait_on_bit_lock(&xprt->state, XPRT_LOCKED, TASK_UNINTERRUPTIBLE);
1410 
1411         del_timer_sync(&xprt->timer);
1412 
1413         rpc_xprt_debugfs_unregister(xprt);
1414         rpc_destroy_wait_queue(&xprt->binding);
1415         rpc_destroy_wait_queue(&xprt->pending);
1416         rpc_destroy_wait_queue(&xprt->sending);
1417         rpc_destroy_wait_queue(&xprt->backlog);
1418         cancel_work_sync(&xprt->task_cleanup);
1419         kfree(xprt->servername);
1420         /*
1421          * Tear down transport state and free the rpc_xprt
1422          */
1423         xprt->ops->destroy(xprt);
1424 }
1425 
1426 static void xprt_destroy_kref(struct kref *kref)
1427 {
1428         xprt_destroy(container_of(kref, struct rpc_xprt, kref));
1429 }
1430 
1431 /**
1432  * xprt_get - return a reference to an RPC transport.
1433  * @xprt: pointer to the transport
1434  *
1435  */
1436 struct rpc_xprt *xprt_get(struct rpc_xprt *xprt)
1437 {
1438         if (xprt != NULL && kref_get_unless_zero(&xprt->kref))
1439                 return xprt;
1440         return NULL;
1441 }
1442 EXPORT_SYMBOL_GPL(xprt_get);
1443 
1444 /**
1445  * xprt_put - release a reference to an RPC transport.
1446  * @xprt: pointer to the transport
1447  *
1448  */
1449 void xprt_put(struct rpc_xprt *xprt)
1450 {
1451         if (xprt != NULL)
1452                 kref_put(&xprt->kref, xprt_destroy_kref);
1453 }
1454 EXPORT_SYMBOL_GPL(xprt_put);
1455 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp