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Commit | Line | Data |
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1da177e4 LT |
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 | |
55aa4f58 CL |
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 | |
1da177e4 LT |
16 | * is run after the packet's timeout has expired. |
17 | * - When a packet arrives, the data_ready handler walks the list of | |
55aa4f58 | 18 | * pending requests for that transport. If a matching XID is found, the |
1da177e4 LT |
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> | |
55aa4f58 CL |
35 | * |
36 | * Transport switch API copyright (C) 2005, Chuck Lever <cel@netapp.com> | |
1da177e4 LT |
37 | */ |
38 | ||
a246b010 CL |
39 | #include <linux/module.h> |
40 | ||
1da177e4 | 41 | #include <linux/types.h> |
a246b010 | 42 | #include <linux/interrupt.h> |
1da177e4 LT |
43 | #include <linux/workqueue.h> |
44 | #include <linux/random.h> | |
45 | ||
a246b010 | 46 | #include <linux/sunrpc/clnt.h> |
11c556b3 | 47 | #include <linux/sunrpc/metrics.h> |
1da177e4 LT |
48 | |
49 | /* | |
50 | * Local variables | |
51 | */ | |
52 | ||
53 | #ifdef RPC_DEBUG | |
1da177e4 LT |
54 | # define RPCDBG_FACILITY RPCDBG_XPRT |
55 | #endif | |
56 | ||
1da177e4 LT |
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 *); | |
1da177e4 | 62 | static void xprt_connect_status(struct rpc_task *task); |
1da177e4 LT |
63 | static int __xprt_get_cong(struct rpc_xprt *, struct rpc_task *); |
64 | ||
555ee3af CL |
65 | /* |
66 | * The transport code maintains an estimate on the maximum number of out- | |
67 | * standing RPC requests, using a smoothed version of the congestion | |
68 | * avoidance implemented in 44BSD. This is basically the Van Jacobson | |
69 | * congestion algorithm: If a retransmit occurs, the congestion window is | |
70 | * halved; otherwise, it is incremented by 1/cwnd when | |
71 | * | |
72 | * - a reply is received and | |
73 | * - a full number of requests are outstanding and | |
74 | * - the congestion window hasn't been updated recently. | |
75 | */ | |
76 | #define RPC_CWNDSHIFT (8U) | |
77 | #define RPC_CWNDSCALE (1U << RPC_CWNDSHIFT) | |
78 | #define RPC_INITCWND RPC_CWNDSCALE | |
79 | #define RPC_MAXCWND(xprt) ((xprt)->max_reqs << RPC_CWNDSHIFT) | |
80 | ||
81 | #define RPCXPRT_CONGESTED(xprt) ((xprt)->cong >= (xprt)->cwnd) | |
1da177e4 | 82 | |
12a80469 CL |
83 | /** |
84 | * xprt_reserve_xprt - serialize write access to transports | |
85 | * @task: task that is requesting access to the transport | |
86 | * | |
87 | * This prevents mixing the payload of separate requests, and prevents | |
88 | * transport connects from colliding with writes. No congestion control | |
89 | * is provided. | |
90 | */ | |
91 | int xprt_reserve_xprt(struct rpc_task *task) | |
92 | { | |
93 | struct rpc_xprt *xprt = task->tk_xprt; | |
94 | struct rpc_rqst *req = task->tk_rqstp; | |
95 | ||
96 | if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) { | |
97 | if (task == xprt->snd_task) | |
98 | return 1; | |
99 | if (task == NULL) | |
100 | return 0; | |
101 | goto out_sleep; | |
102 | } | |
103 | xprt->snd_task = task; | |
104 | if (req) { | |
105 | req->rq_bytes_sent = 0; | |
106 | req->rq_ntrans++; | |
107 | } | |
108 | return 1; | |
109 | ||
110 | out_sleep: | |
111 | dprintk("RPC: %4d failed to lock transport %p\n", | |
112 | task->tk_pid, xprt); | |
113 | task->tk_timeout = 0; | |
114 | task->tk_status = -EAGAIN; | |
115 | if (req && req->rq_ntrans) | |
116 | rpc_sleep_on(&xprt->resend, task, NULL, NULL); | |
117 | else | |
118 | rpc_sleep_on(&xprt->sending, task, NULL, NULL); | |
119 | return 0; | |
120 | } | |
121 | ||
632e3bdc TM |
122 | static void xprt_clear_locked(struct rpc_xprt *xprt) |
123 | { | |
124 | xprt->snd_task = NULL; | |
125 | if (!test_bit(XPRT_CLOSE_WAIT, &xprt->state) || xprt->shutdown) { | |
126 | smp_mb__before_clear_bit(); | |
127 | clear_bit(XPRT_LOCKED, &xprt->state); | |
128 | smp_mb__after_clear_bit(); | |
129 | } else | |
130 | schedule_work(&xprt->task_cleanup); | |
131 | } | |
132 | ||
1da177e4 | 133 | /* |
12a80469 CL |
134 | * xprt_reserve_xprt_cong - serialize write access to transports |
135 | * @task: task that is requesting access to the transport | |
136 | * | |
137 | * Same as xprt_reserve_xprt, but Van Jacobson congestion control is | |
138 | * integrated into the decision of whether a request is allowed to be | |
139 | * woken up and given access to the transport. | |
1da177e4 | 140 | */ |
12a80469 | 141 | int xprt_reserve_xprt_cong(struct rpc_task *task) |
1da177e4 | 142 | { |
12a80469 | 143 | struct rpc_xprt *xprt = task->tk_xprt; |
1da177e4 LT |
144 | struct rpc_rqst *req = task->tk_rqstp; |
145 | ||
2226feb6 | 146 | if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) { |
1da177e4 LT |
147 | if (task == xprt->snd_task) |
148 | return 1; | |
1da177e4 LT |
149 | goto out_sleep; |
150 | } | |
12a80469 | 151 | if (__xprt_get_cong(xprt, task)) { |
1da177e4 LT |
152 | xprt->snd_task = task; |
153 | if (req) { | |
154 | req->rq_bytes_sent = 0; | |
155 | req->rq_ntrans++; | |
156 | } | |
157 | return 1; | |
158 | } | |
632e3bdc | 159 | xprt_clear_locked(xprt); |
1da177e4 | 160 | out_sleep: |
55aa4f58 | 161 | dprintk("RPC: %4d failed to lock transport %p\n", task->tk_pid, xprt); |
1da177e4 LT |
162 | task->tk_timeout = 0; |
163 | task->tk_status = -EAGAIN; | |
164 | if (req && req->rq_ntrans) | |
165 | rpc_sleep_on(&xprt->resend, task, NULL, NULL); | |
166 | else | |
167 | rpc_sleep_on(&xprt->sending, task, NULL, NULL); | |
168 | return 0; | |
169 | } | |
170 | ||
12a80469 | 171 | static inline int xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task) |
1da177e4 LT |
172 | { |
173 | int retval; | |
174 | ||
4a0f8c04 | 175 | spin_lock_bh(&xprt->transport_lock); |
12a80469 | 176 | retval = xprt->ops->reserve_xprt(task); |
4a0f8c04 | 177 | spin_unlock_bh(&xprt->transport_lock); |
1da177e4 LT |
178 | return retval; |
179 | } | |
180 | ||
12a80469 | 181 | static void __xprt_lock_write_next(struct rpc_xprt *xprt) |
49e9a890 CL |
182 | { |
183 | struct rpc_task *task; | |
184 | struct rpc_rqst *req; | |
185 | ||
186 | if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) | |
187 | return; | |
188 | ||
189 | task = rpc_wake_up_next(&xprt->resend); | |
190 | if (!task) { | |
191 | task = rpc_wake_up_next(&xprt->sending); | |
192 | if (!task) | |
193 | goto out_unlock; | |
194 | } | |
195 | ||
196 | req = task->tk_rqstp; | |
197 | xprt->snd_task = task; | |
198 | if (req) { | |
199 | req->rq_bytes_sent = 0; | |
200 | req->rq_ntrans++; | |
201 | } | |
202 | return; | |
203 | ||
204 | out_unlock: | |
632e3bdc | 205 | xprt_clear_locked(xprt); |
49e9a890 CL |
206 | } |
207 | ||
208 | static void __xprt_lock_write_next_cong(struct rpc_xprt *xprt) | |
1da177e4 LT |
209 | { |
210 | struct rpc_task *task; | |
211 | ||
2226feb6 | 212 | if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) |
1da177e4 | 213 | return; |
49e9a890 | 214 | if (RPCXPRT_CONGESTED(xprt)) |
1da177e4 LT |
215 | goto out_unlock; |
216 | task = rpc_wake_up_next(&xprt->resend); | |
217 | if (!task) { | |
218 | task = rpc_wake_up_next(&xprt->sending); | |
219 | if (!task) | |
220 | goto out_unlock; | |
221 | } | |
49e9a890 | 222 | if (__xprt_get_cong(xprt, task)) { |
1da177e4 LT |
223 | struct rpc_rqst *req = task->tk_rqstp; |
224 | xprt->snd_task = task; | |
225 | if (req) { | |
226 | req->rq_bytes_sent = 0; | |
227 | req->rq_ntrans++; | |
228 | } | |
229 | return; | |
230 | } | |
231 | out_unlock: | |
632e3bdc | 232 | xprt_clear_locked(xprt); |
1da177e4 LT |
233 | } |
234 | ||
49e9a890 CL |
235 | /** |
236 | * xprt_release_xprt - allow other requests to use a transport | |
237 | * @xprt: transport with other tasks potentially waiting | |
238 | * @task: task that is releasing access to the transport | |
239 | * | |
240 | * Note that "task" can be NULL. No congestion control is provided. | |
1da177e4 | 241 | */ |
49e9a890 | 242 | void xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task) |
1da177e4 LT |
243 | { |
244 | if (xprt->snd_task == task) { | |
632e3bdc | 245 | xprt_clear_locked(xprt); |
1da177e4 LT |
246 | __xprt_lock_write_next(xprt); |
247 | } | |
248 | } | |
249 | ||
49e9a890 CL |
250 | /** |
251 | * xprt_release_xprt_cong - allow other requests to use a transport | |
252 | * @xprt: transport with other tasks potentially waiting | |
253 | * @task: task that is releasing access to the transport | |
254 | * | |
255 | * Note that "task" can be NULL. Another task is awoken to use the | |
256 | * transport if the transport's congestion window allows it. | |
257 | */ | |
258 | void xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task) | |
259 | { | |
260 | if (xprt->snd_task == task) { | |
632e3bdc | 261 | xprt_clear_locked(xprt); |
49e9a890 CL |
262 | __xprt_lock_write_next_cong(xprt); |
263 | } | |
264 | } | |
265 | ||
266 | static inline void xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task) | |
1da177e4 | 267 | { |
4a0f8c04 | 268 | spin_lock_bh(&xprt->transport_lock); |
49e9a890 | 269 | xprt->ops->release_xprt(xprt, task); |
4a0f8c04 | 270 | spin_unlock_bh(&xprt->transport_lock); |
1da177e4 LT |
271 | } |
272 | ||
1da177e4 LT |
273 | /* |
274 | * Van Jacobson congestion avoidance. Check if the congestion window | |
275 | * overflowed. Put the task to sleep if this is the case. | |
276 | */ | |
277 | static int | |
278 | __xprt_get_cong(struct rpc_xprt *xprt, struct rpc_task *task) | |
279 | { | |
280 | struct rpc_rqst *req = task->tk_rqstp; | |
281 | ||
282 | if (req->rq_cong) | |
283 | return 1; | |
284 | dprintk("RPC: %4d xprt_cwnd_limited cong = %ld cwnd = %ld\n", | |
285 | task->tk_pid, xprt->cong, xprt->cwnd); | |
286 | if (RPCXPRT_CONGESTED(xprt)) | |
287 | return 0; | |
288 | req->rq_cong = 1; | |
289 | xprt->cong += RPC_CWNDSCALE; | |
290 | return 1; | |
291 | } | |
292 | ||
293 | /* | |
294 | * Adjust the congestion window, and wake up the next task | |
295 | * that has been sleeping due to congestion | |
296 | */ | |
297 | static void | |
298 | __xprt_put_cong(struct rpc_xprt *xprt, struct rpc_rqst *req) | |
299 | { | |
300 | if (!req->rq_cong) | |
301 | return; | |
302 | req->rq_cong = 0; | |
303 | xprt->cong -= RPC_CWNDSCALE; | |
49e9a890 | 304 | __xprt_lock_write_next_cong(xprt); |
1da177e4 LT |
305 | } |
306 | ||
a58dd398 CL |
307 | /** |
308 | * xprt_release_rqst_cong - housekeeping when request is complete | |
309 | * @task: RPC request that recently completed | |
310 | * | |
311 | * Useful for transports that require congestion control. | |
312 | */ | |
313 | void xprt_release_rqst_cong(struct rpc_task *task) | |
314 | { | |
315 | __xprt_put_cong(task->tk_xprt, task->tk_rqstp); | |
316 | } | |
317 | ||
46c0ee8b CL |
318 | /** |
319 | * xprt_adjust_cwnd - adjust transport congestion window | |
320 | * @task: recently completed RPC request used to adjust window | |
321 | * @result: result code of completed RPC request | |
322 | * | |
1da177e4 LT |
323 | * We use a time-smoothed congestion estimator to avoid heavy oscillation. |
324 | */ | |
46c0ee8b | 325 | void xprt_adjust_cwnd(struct rpc_task *task, int result) |
1da177e4 | 326 | { |
46c0ee8b CL |
327 | struct rpc_rqst *req = task->tk_rqstp; |
328 | struct rpc_xprt *xprt = task->tk_xprt; | |
329 | unsigned long cwnd = xprt->cwnd; | |
1da177e4 | 330 | |
1da177e4 LT |
331 | if (result >= 0 && cwnd <= xprt->cong) { |
332 | /* The (cwnd >> 1) term makes sure | |
333 | * the result gets rounded properly. */ | |
334 | cwnd += (RPC_CWNDSCALE * RPC_CWNDSCALE + (cwnd >> 1)) / cwnd; | |
335 | if (cwnd > RPC_MAXCWND(xprt)) | |
336 | cwnd = RPC_MAXCWND(xprt); | |
49e9a890 | 337 | __xprt_lock_write_next_cong(xprt); |
1da177e4 LT |
338 | } else if (result == -ETIMEDOUT) { |
339 | cwnd >>= 1; | |
340 | if (cwnd < RPC_CWNDSCALE) | |
341 | cwnd = RPC_CWNDSCALE; | |
342 | } | |
343 | dprintk("RPC: cong %ld, cwnd was %ld, now %ld\n", | |
344 | xprt->cong, xprt->cwnd, cwnd); | |
345 | xprt->cwnd = cwnd; | |
46c0ee8b | 346 | __xprt_put_cong(xprt, req); |
1da177e4 LT |
347 | } |
348 | ||
44fbac22 CL |
349 | /** |
350 | * xprt_wake_pending_tasks - wake all tasks on a transport's pending queue | |
351 | * @xprt: transport with waiting tasks | |
352 | * @status: result code to plant in each task before waking it | |
353 | * | |
354 | */ | |
355 | void xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status) | |
356 | { | |
357 | if (status < 0) | |
358 | rpc_wake_up_status(&xprt->pending, status); | |
359 | else | |
360 | rpc_wake_up(&xprt->pending); | |
361 | } | |
362 | ||
c7b2cae8 CL |
363 | /** |
364 | * xprt_wait_for_buffer_space - wait for transport output buffer to clear | |
365 | * @task: task to be put to sleep | |
366 | * | |
367 | */ | |
368 | void xprt_wait_for_buffer_space(struct rpc_task *task) | |
369 | { | |
370 | struct rpc_rqst *req = task->tk_rqstp; | |
371 | struct rpc_xprt *xprt = req->rq_xprt; | |
372 | ||
373 | task->tk_timeout = req->rq_timeout; | |
374 | rpc_sleep_on(&xprt->pending, task, NULL, NULL); | |
375 | } | |
376 | ||
377 | /** | |
378 | * xprt_write_space - wake the task waiting for transport output buffer space | |
379 | * @xprt: transport with waiting tasks | |
380 | * | |
381 | * Can be called in a soft IRQ context, so xprt_write_space never sleeps. | |
382 | */ | |
383 | void xprt_write_space(struct rpc_xprt *xprt) | |
384 | { | |
385 | if (unlikely(xprt->shutdown)) | |
386 | return; | |
387 | ||
388 | spin_lock_bh(&xprt->transport_lock); | |
389 | if (xprt->snd_task) { | |
390 | dprintk("RPC: write space: waking waiting task on xprt %p\n", | |
391 | xprt); | |
392 | rpc_wake_up_task(xprt->snd_task); | |
393 | } | |
394 | spin_unlock_bh(&xprt->transport_lock); | |
395 | } | |
396 | ||
fe3aca29 CL |
397 | /** |
398 | * xprt_set_retrans_timeout_def - set a request's retransmit timeout | |
399 | * @task: task whose timeout is to be set | |
400 | * | |
401 | * Set a request's retransmit timeout based on the transport's | |
402 | * default timeout parameters. Used by transports that don't adjust | |
403 | * the retransmit timeout based on round-trip time estimation. | |
404 | */ | |
405 | void xprt_set_retrans_timeout_def(struct rpc_task *task) | |
406 | { | |
407 | task->tk_timeout = task->tk_rqstp->rq_timeout; | |
408 | } | |
409 | ||
410 | /* | |
411 | * xprt_set_retrans_timeout_rtt - set a request's retransmit timeout | |
412 | * @task: task whose timeout is to be set | |
413 | * | |
414 | * Set a request's retransmit timeout using the RTT estimator. | |
415 | */ | |
416 | void xprt_set_retrans_timeout_rtt(struct rpc_task *task) | |
417 | { | |
418 | int timer = task->tk_msg.rpc_proc->p_timer; | |
419 | struct rpc_rtt *rtt = task->tk_client->cl_rtt; | |
420 | struct rpc_rqst *req = task->tk_rqstp; | |
421 | unsigned long max_timeout = req->rq_xprt->timeout.to_maxval; | |
422 | ||
423 | task->tk_timeout = rpc_calc_rto(rtt, timer); | |
424 | task->tk_timeout <<= rpc_ntimeo(rtt, timer) + req->rq_retries; | |
425 | if (task->tk_timeout > max_timeout || task->tk_timeout == 0) | |
426 | task->tk_timeout = max_timeout; | |
427 | } | |
428 | ||
1da177e4 LT |
429 | static void xprt_reset_majortimeo(struct rpc_rqst *req) |
430 | { | |
431 | struct rpc_timeout *to = &req->rq_xprt->timeout; | |
432 | ||
433 | req->rq_majortimeo = req->rq_timeout; | |
434 | if (to->to_exponential) | |
435 | req->rq_majortimeo <<= to->to_retries; | |
436 | else | |
437 | req->rq_majortimeo += to->to_increment * to->to_retries; | |
438 | if (req->rq_majortimeo > to->to_maxval || req->rq_majortimeo == 0) | |
439 | req->rq_majortimeo = to->to_maxval; | |
440 | req->rq_majortimeo += jiffies; | |
441 | } | |
442 | ||
9903cd1c CL |
443 | /** |
444 | * xprt_adjust_timeout - adjust timeout values for next retransmit | |
445 | * @req: RPC request containing parameters to use for the adjustment | |
446 | * | |
1da177e4 LT |
447 | */ |
448 | int xprt_adjust_timeout(struct rpc_rqst *req) | |
449 | { | |
450 | struct rpc_xprt *xprt = req->rq_xprt; | |
451 | struct rpc_timeout *to = &xprt->timeout; | |
452 | int status = 0; | |
453 | ||
454 | if (time_before(jiffies, req->rq_majortimeo)) { | |
455 | if (to->to_exponential) | |
456 | req->rq_timeout <<= 1; | |
457 | else | |
458 | req->rq_timeout += to->to_increment; | |
459 | if (to->to_maxval && req->rq_timeout >= to->to_maxval) | |
460 | req->rq_timeout = to->to_maxval; | |
461 | req->rq_retries++; | |
462 | pprintk("RPC: %lu retrans\n", jiffies); | |
463 | } else { | |
464 | req->rq_timeout = to->to_initval; | |
465 | req->rq_retries = 0; | |
466 | xprt_reset_majortimeo(req); | |
467 | /* Reset the RTT counters == "slow start" */ | |
4a0f8c04 | 468 | spin_lock_bh(&xprt->transport_lock); |
1da177e4 | 469 | rpc_init_rtt(req->rq_task->tk_client->cl_rtt, to->to_initval); |
4a0f8c04 | 470 | spin_unlock_bh(&xprt->transport_lock); |
1da177e4 LT |
471 | pprintk("RPC: %lu timeout\n", jiffies); |
472 | status = -ETIMEDOUT; | |
473 | } | |
474 | ||
475 | if (req->rq_timeout == 0) { | |
476 | printk(KERN_WARNING "xprt_adjust_timeout: rq_timeout = 0!\n"); | |
477 | req->rq_timeout = 5 * HZ; | |
478 | } | |
479 | return status; | |
480 | } | |
481 | ||
55aa4f58 | 482 | static void xprt_autoclose(void *args) |
1da177e4 LT |
483 | { |
484 | struct rpc_xprt *xprt = (struct rpc_xprt *)args; | |
485 | ||
486 | xprt_disconnect(xprt); | |
a246b010 | 487 | xprt->ops->close(xprt); |
1da177e4 LT |
488 | xprt_release_write(xprt, NULL); |
489 | } | |
490 | ||
9903cd1c CL |
491 | /** |
492 | * xprt_disconnect - mark a transport as disconnected | |
493 | * @xprt: transport to flag for disconnect | |
494 | * | |
1da177e4 | 495 | */ |
a246b010 | 496 | void xprt_disconnect(struct rpc_xprt *xprt) |
1da177e4 LT |
497 | { |
498 | dprintk("RPC: disconnected transport %p\n", xprt); | |
4a0f8c04 | 499 | spin_lock_bh(&xprt->transport_lock); |
1da177e4 | 500 | xprt_clear_connected(xprt); |
44fbac22 | 501 | xprt_wake_pending_tasks(xprt, -ENOTCONN); |
4a0f8c04 | 502 | spin_unlock_bh(&xprt->transport_lock); |
1da177e4 LT |
503 | } |
504 | ||
1da177e4 LT |
505 | static void |
506 | xprt_init_autodisconnect(unsigned long data) | |
507 | { | |
508 | struct rpc_xprt *xprt = (struct rpc_xprt *)data; | |
509 | ||
4a0f8c04 | 510 | spin_lock(&xprt->transport_lock); |
1da177e4 LT |
511 | if (!list_empty(&xprt->recv) || xprt->shutdown) |
512 | goto out_abort; | |
2226feb6 | 513 | if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) |
1da177e4 | 514 | goto out_abort; |
4a0f8c04 | 515 | spin_unlock(&xprt->transport_lock); |
2226feb6 | 516 | if (xprt_connecting(xprt)) |
1da177e4 LT |
517 | xprt_release_write(xprt, NULL); |
518 | else | |
519 | schedule_work(&xprt->task_cleanup); | |
520 | return; | |
521 | out_abort: | |
4a0f8c04 | 522 | spin_unlock(&xprt->transport_lock); |
1da177e4 LT |
523 | } |
524 | ||
9903cd1c CL |
525 | /** |
526 | * xprt_connect - schedule a transport connect operation | |
527 | * @task: RPC task that is requesting the connect | |
1da177e4 LT |
528 | * |
529 | */ | |
530 | void xprt_connect(struct rpc_task *task) | |
531 | { | |
532 | struct rpc_xprt *xprt = task->tk_xprt; | |
533 | ||
534 | dprintk("RPC: %4d xprt_connect xprt %p %s connected\n", task->tk_pid, | |
535 | xprt, (xprt_connected(xprt) ? "is" : "is not")); | |
536 | ||
1da177e4 LT |
537 | if (!xprt->addr.sin_port) { |
538 | task->tk_status = -EIO; | |
539 | return; | |
540 | } | |
541 | if (!xprt_lock_write(xprt, task)) | |
542 | return; | |
543 | if (xprt_connected(xprt)) | |
a246b010 CL |
544 | xprt_release_write(xprt, task); |
545 | else { | |
546 | if (task->tk_rqstp) | |
547 | task->tk_rqstp->rq_bytes_sent = 0; | |
1da177e4 | 548 | |
03bf4b70 | 549 | task->tk_timeout = xprt->connect_timeout; |
a246b010 | 550 | rpc_sleep_on(&xprt->pending, task, xprt_connect_status, NULL); |
262ca07d | 551 | xprt->stat.connect_start = jiffies; |
a246b010 | 552 | xprt->ops->connect(task); |
1da177e4 LT |
553 | } |
554 | return; | |
1da177e4 LT |
555 | } |
556 | ||
9903cd1c | 557 | static void xprt_connect_status(struct rpc_task *task) |
1da177e4 LT |
558 | { |
559 | struct rpc_xprt *xprt = task->tk_xprt; | |
560 | ||
561 | if (task->tk_status >= 0) { | |
262ca07d CL |
562 | xprt->stat.connect_count++; |
563 | xprt->stat.connect_time += (long)jiffies - xprt->stat.connect_start; | |
1da177e4 LT |
564 | dprintk("RPC: %4d xprt_connect_status: connection established\n", |
565 | task->tk_pid); | |
566 | return; | |
567 | } | |
568 | ||
1da177e4 LT |
569 | switch (task->tk_status) { |
570 | case -ECONNREFUSED: | |
571 | case -ECONNRESET: | |
23475d66 CL |
572 | dprintk("RPC: %4d xprt_connect_status: server %s refused connection\n", |
573 | task->tk_pid, task->tk_client->cl_server); | |
574 | break; | |
1da177e4 | 575 | case -ENOTCONN: |
23475d66 CL |
576 | dprintk("RPC: %4d xprt_connect_status: connection broken\n", |
577 | task->tk_pid); | |
578 | break; | |
1da177e4 | 579 | case -ETIMEDOUT: |
23475d66 | 580 | dprintk("RPC: %4d xprt_connect_status: connect attempt timed out\n", |
1da177e4 LT |
581 | task->tk_pid); |
582 | break; | |
583 | default: | |
23475d66 CL |
584 | dprintk("RPC: %4d xprt_connect_status: error %d connecting to server %s\n", |
585 | task->tk_pid, -task->tk_status, task->tk_client->cl_server); | |
586 | xprt_release_write(xprt, task); | |
587 | task->tk_status = -EIO; | |
588 | return; | |
589 | } | |
590 | ||
591 | /* if soft mounted, just cause this RPC to fail */ | |
592 | if (RPC_IS_SOFT(task)) { | |
593 | xprt_release_write(xprt, task); | |
594 | task->tk_status = -EIO; | |
1da177e4 | 595 | } |
1da177e4 LT |
596 | } |
597 | ||
9903cd1c CL |
598 | /** |
599 | * xprt_lookup_rqst - find an RPC request corresponding to an XID | |
600 | * @xprt: transport on which the original request was transmitted | |
601 | * @xid: RPC XID of incoming reply | |
602 | * | |
1da177e4 | 603 | */ |
a246b010 | 604 | struct rpc_rqst *xprt_lookup_rqst(struct rpc_xprt *xprt, u32 xid) |
1da177e4 LT |
605 | { |
606 | struct list_head *pos; | |
1da177e4 LT |
607 | |
608 | list_for_each(pos, &xprt->recv) { | |
609 | struct rpc_rqst *entry = list_entry(pos, struct rpc_rqst, rq_list); | |
262ca07d CL |
610 | if (entry->rq_xid == xid) |
611 | return entry; | |
1da177e4 | 612 | } |
262ca07d CL |
613 | xprt->stat.bad_xids++; |
614 | return NULL; | |
1da177e4 LT |
615 | } |
616 | ||
1570c1e4 CL |
617 | /** |
618 | * xprt_update_rtt - update an RPC client's RTT state after receiving a reply | |
619 | * @task: RPC request that recently completed | |
620 | * | |
621 | */ | |
622 | void xprt_update_rtt(struct rpc_task *task) | |
623 | { | |
624 | struct rpc_rqst *req = task->tk_rqstp; | |
625 | struct rpc_rtt *rtt = task->tk_client->cl_rtt; | |
626 | unsigned timer = task->tk_msg.rpc_proc->p_timer; | |
627 | ||
628 | if (timer) { | |
629 | if (req->rq_ntrans == 1) | |
630 | rpc_update_rtt(rtt, timer, | |
631 | (long)jiffies - req->rq_xtime); | |
632 | rpc_set_timeo(rtt, timer, req->rq_ntrans - 1); | |
633 | } | |
634 | } | |
635 | ||
9903cd1c CL |
636 | /** |
637 | * xprt_complete_rqst - called when reply processing is complete | |
1570c1e4 | 638 | * @task: RPC request that recently completed |
9903cd1c CL |
639 | * @copied: actual number of bytes received from the transport |
640 | * | |
1570c1e4 | 641 | * Caller holds transport lock. |
1da177e4 | 642 | */ |
1570c1e4 | 643 | void xprt_complete_rqst(struct rpc_task *task, int copied) |
1da177e4 | 644 | { |
1570c1e4 | 645 | struct rpc_rqst *req = task->tk_rqstp; |
1da177e4 | 646 | |
1570c1e4 CL |
647 | dprintk("RPC: %5u xid %08x complete (%d bytes received)\n", |
648 | task->tk_pid, ntohl(req->rq_xid), copied); | |
1da177e4 | 649 | |
262ca07d | 650 | task->tk_xprt->stat.recvs++; |
ef759a2e CL |
651 | task->tk_rtt = (long)jiffies - req->rq_xtime; |
652 | ||
1da177e4 | 653 | list_del_init(&req->rq_list); |
43ac3f29 TM |
654 | /* Ensure all writes are done before we update req->rq_received */ |
655 | smp_wmb(); | |
1da177e4 | 656 | req->rq_received = req->rq_private_buf.len = copied; |
1da177e4 | 657 | rpc_wake_up_task(task); |
1da177e4 LT |
658 | } |
659 | ||
46c0ee8b | 660 | static void xprt_timer(struct rpc_task *task) |
1da177e4 | 661 | { |
46c0ee8b | 662 | struct rpc_rqst *req = task->tk_rqstp; |
1da177e4 LT |
663 | struct rpc_xprt *xprt = req->rq_xprt; |
664 | ||
46c0ee8b | 665 | dprintk("RPC: %4d xprt_timer\n", task->tk_pid); |
1da177e4 | 666 | |
46c0ee8b CL |
667 | spin_lock(&xprt->transport_lock); |
668 | if (!req->rq_received) { | |
669 | if (xprt->ops->timer) | |
670 | xprt->ops->timer(task); | |
671 | task->tk_status = -ETIMEDOUT; | |
672 | } | |
1da177e4 LT |
673 | task->tk_timeout = 0; |
674 | rpc_wake_up_task(task); | |
4a0f8c04 | 675 | spin_unlock(&xprt->transport_lock); |
1da177e4 LT |
676 | } |
677 | ||
9903cd1c CL |
678 | /** |
679 | * xprt_prepare_transmit - reserve the transport before sending a request | |
680 | * @task: RPC task about to send a request | |
681 | * | |
1da177e4 | 682 | */ |
9903cd1c | 683 | int xprt_prepare_transmit(struct rpc_task *task) |
1da177e4 LT |
684 | { |
685 | struct rpc_rqst *req = task->tk_rqstp; | |
686 | struct rpc_xprt *xprt = req->rq_xprt; | |
687 | int err = 0; | |
688 | ||
689 | dprintk("RPC: %4d xprt_prepare_transmit\n", task->tk_pid); | |
690 | ||
4a0f8c04 | 691 | spin_lock_bh(&xprt->transport_lock); |
1da177e4 LT |
692 | if (req->rq_received && !req->rq_bytes_sent) { |
693 | err = req->rq_received; | |
694 | goto out_unlock; | |
695 | } | |
12a80469 | 696 | if (!xprt->ops->reserve_xprt(task)) { |
1da177e4 LT |
697 | err = -EAGAIN; |
698 | goto out_unlock; | |
699 | } | |
700 | ||
701 | if (!xprt_connected(xprt)) { | |
702 | err = -ENOTCONN; | |
703 | goto out_unlock; | |
704 | } | |
705 | out_unlock: | |
4a0f8c04 | 706 | spin_unlock_bh(&xprt->transport_lock); |
1da177e4 LT |
707 | return err; |
708 | } | |
709 | ||
5e5ce5be TM |
710 | void |
711 | xprt_abort_transmit(struct rpc_task *task) | |
712 | { | |
713 | struct rpc_xprt *xprt = task->tk_xprt; | |
714 | ||
715 | xprt_release_write(xprt, task); | |
716 | } | |
717 | ||
9903cd1c CL |
718 | /** |
719 | * xprt_transmit - send an RPC request on a transport | |
720 | * @task: controlling RPC task | |
721 | * | |
722 | * We have to copy the iovec because sendmsg fiddles with its contents. | |
723 | */ | |
724 | void xprt_transmit(struct rpc_task *task) | |
1da177e4 | 725 | { |
1da177e4 LT |
726 | struct rpc_rqst *req = task->tk_rqstp; |
727 | struct rpc_xprt *xprt = req->rq_xprt; | |
a246b010 | 728 | int status; |
1da177e4 LT |
729 | |
730 | dprintk("RPC: %4d xprt_transmit(%u)\n", task->tk_pid, req->rq_slen); | |
731 | ||
1da177e4 LT |
732 | if (!req->rq_received) { |
733 | if (list_empty(&req->rq_list)) { | |
4a0f8c04 | 734 | spin_lock_bh(&xprt->transport_lock); |
1da177e4 LT |
735 | /* Update the softirq receive buffer */ |
736 | memcpy(&req->rq_private_buf, &req->rq_rcv_buf, | |
737 | sizeof(req->rq_private_buf)); | |
738 | /* Add request to the receive list */ | |
739 | list_add_tail(&req->rq_list, &xprt->recv); | |
4a0f8c04 | 740 | spin_unlock_bh(&xprt->transport_lock); |
1da177e4 | 741 | xprt_reset_majortimeo(req); |
0f9dc2b1 TM |
742 | /* Turn off autodisconnect */ |
743 | del_singleshot_timer_sync(&xprt->timer); | |
1da177e4 LT |
744 | } |
745 | } else if (!req->rq_bytes_sent) | |
746 | return; | |
747 | ||
a246b010 | 748 | status = xprt->ops->send_request(task); |
fe3aca29 CL |
749 | if (status == 0) { |
750 | dprintk("RPC: %4d xmit complete\n", task->tk_pid); | |
751 | spin_lock_bh(&xprt->transport_lock); | |
262ca07d | 752 | |
fe3aca29 | 753 | xprt->ops->set_retrans_timeout(task); |
262ca07d CL |
754 | |
755 | xprt->stat.sends++; | |
756 | xprt->stat.req_u += xprt->stat.sends - xprt->stat.recvs; | |
757 | xprt->stat.bklog_u += xprt->backlog.qlen; | |
758 | ||
fe3aca29 CL |
759 | /* Don't race with disconnect */ |
760 | if (!xprt_connected(xprt)) | |
761 | task->tk_status = -ENOTCONN; | |
762 | else if (!req->rq_received) | |
763 | rpc_sleep_on(&xprt->pending, task, NULL, xprt_timer); | |
262ca07d | 764 | |
49e9a890 | 765 | xprt->ops->release_xprt(xprt, task); |
fe3aca29 CL |
766 | spin_unlock_bh(&xprt->transport_lock); |
767 | return; | |
768 | } | |
1da177e4 LT |
769 | |
770 | /* Note: at this point, task->tk_sleeping has not yet been set, | |
771 | * hence there is no danger of the waking up task being put on | |
772 | * schedq, and being picked up by a parallel run of rpciod(). | |
773 | */ | |
774 | task->tk_status = status; | |
775 | ||
776 | switch (status) { | |
1da177e4 | 777 | case -ECONNREFUSED: |
1da177e4 | 778 | rpc_sleep_on(&xprt->sending, task, NULL, NULL); |
a246b010 | 779 | case -EAGAIN: |
1da177e4 LT |
780 | case -ENOTCONN: |
781 | return; | |
782 | default: | |
43118c29 | 783 | break; |
1da177e4 LT |
784 | } |
785 | xprt_release_write(xprt, task); | |
786 | return; | |
1da177e4 LT |
787 | } |
788 | ||
9903cd1c | 789 | static inline void do_xprt_reserve(struct rpc_task *task) |
1da177e4 LT |
790 | { |
791 | struct rpc_xprt *xprt = task->tk_xprt; | |
792 | ||
793 | task->tk_status = 0; | |
794 | if (task->tk_rqstp) | |
795 | return; | |
796 | if (!list_empty(&xprt->free)) { | |
797 | struct rpc_rqst *req = list_entry(xprt->free.next, struct rpc_rqst, rq_list); | |
798 | list_del_init(&req->rq_list); | |
799 | task->tk_rqstp = req; | |
800 | xprt_request_init(task, xprt); | |
801 | return; | |
802 | } | |
803 | dprintk("RPC: waiting for request slot\n"); | |
804 | task->tk_status = -EAGAIN; | |
805 | task->tk_timeout = 0; | |
806 | rpc_sleep_on(&xprt->backlog, task, NULL, NULL); | |
807 | } | |
808 | ||
9903cd1c CL |
809 | /** |
810 | * xprt_reserve - allocate an RPC request slot | |
811 | * @task: RPC task requesting a slot allocation | |
812 | * | |
813 | * If no more slots are available, place the task on the transport's | |
814 | * backlog queue. | |
815 | */ | |
816 | void xprt_reserve(struct rpc_task *task) | |
1da177e4 LT |
817 | { |
818 | struct rpc_xprt *xprt = task->tk_xprt; | |
819 | ||
820 | task->tk_status = -EIO; | |
0065db32 TM |
821 | spin_lock(&xprt->reserve_lock); |
822 | do_xprt_reserve(task); | |
823 | spin_unlock(&xprt->reserve_lock); | |
1da177e4 LT |
824 | } |
825 | ||
1da177e4 LT |
826 | static inline u32 xprt_alloc_xid(struct rpc_xprt *xprt) |
827 | { | |
828 | return xprt->xid++; | |
829 | } | |
830 | ||
831 | static inline void xprt_init_xid(struct rpc_xprt *xprt) | |
832 | { | |
833 | get_random_bytes(&xprt->xid, sizeof(xprt->xid)); | |
834 | } | |
835 | ||
9903cd1c | 836 | static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt) |
1da177e4 LT |
837 | { |
838 | struct rpc_rqst *req = task->tk_rqstp; | |
839 | ||
840 | req->rq_timeout = xprt->timeout.to_initval; | |
841 | req->rq_task = task; | |
842 | req->rq_xprt = xprt; | |
02107148 CL |
843 | req->rq_buffer = NULL; |
844 | req->rq_bufsize = 0; | |
1da177e4 | 845 | req->rq_xid = xprt_alloc_xid(xprt); |
ead5e1c2 | 846 | req->rq_release_snd_buf = NULL; |
1da177e4 LT |
847 | dprintk("RPC: %4d reserved req %p xid %08x\n", task->tk_pid, |
848 | req, ntohl(req->rq_xid)); | |
849 | } | |
850 | ||
9903cd1c CL |
851 | /** |
852 | * xprt_release - release an RPC request slot | |
853 | * @task: task which is finished with the slot | |
854 | * | |
1da177e4 | 855 | */ |
9903cd1c | 856 | void xprt_release(struct rpc_task *task) |
1da177e4 LT |
857 | { |
858 | struct rpc_xprt *xprt = task->tk_xprt; | |
859 | struct rpc_rqst *req; | |
860 | ||
861 | if (!(req = task->tk_rqstp)) | |
862 | return; | |
11c556b3 | 863 | rpc_count_iostats(task); |
4a0f8c04 | 864 | spin_lock_bh(&xprt->transport_lock); |
49e9a890 | 865 | xprt->ops->release_xprt(xprt, task); |
a58dd398 CL |
866 | if (xprt->ops->release_request) |
867 | xprt->ops->release_request(task); | |
1da177e4 LT |
868 | if (!list_empty(&req->rq_list)) |
869 | list_del(&req->rq_list); | |
870 | xprt->last_used = jiffies; | |
0065db32 | 871 | if (list_empty(&xprt->recv)) |
a246b010 | 872 | mod_timer(&xprt->timer, |
03bf4b70 | 873 | xprt->last_used + xprt->idle_timeout); |
4a0f8c04 | 874 | spin_unlock_bh(&xprt->transport_lock); |
02107148 | 875 | xprt->ops->buf_free(task); |
1da177e4 | 876 | task->tk_rqstp = NULL; |
ead5e1c2 BF |
877 | if (req->rq_release_snd_buf) |
878 | req->rq_release_snd_buf(req); | |
1da177e4 LT |
879 | memset(req, 0, sizeof(*req)); /* mark unused */ |
880 | ||
881 | dprintk("RPC: %4d release request %p\n", task->tk_pid, req); | |
882 | ||
5dc07727 | 883 | spin_lock(&xprt->reserve_lock); |
1da177e4 | 884 | list_add(&req->rq_list, &xprt->free); |
555ee3af | 885 | rpc_wake_up_next(&xprt->backlog); |
5dc07727 | 886 | spin_unlock(&xprt->reserve_lock); |
1da177e4 LT |
887 | } |
888 | ||
9903cd1c CL |
889 | /** |
890 | * xprt_set_timeout - set constant RPC timeout | |
891 | * @to: RPC timeout parameters to set up | |
892 | * @retr: number of retries | |
893 | * @incr: amount of increase after each retry | |
894 | * | |
1da177e4 | 895 | */ |
9903cd1c | 896 | void xprt_set_timeout(struct rpc_timeout *to, unsigned int retr, unsigned long incr) |
1da177e4 LT |
897 | { |
898 | to->to_initval = | |
899 | to->to_increment = incr; | |
eab5c084 | 900 | to->to_maxval = to->to_initval + (incr * retr); |
1da177e4 LT |
901 | to->to_retries = retr; |
902 | to->to_exponential = 0; | |
903 | } | |
904 | ||
9903cd1c | 905 | static struct rpc_xprt *xprt_setup(int proto, struct sockaddr_in *ap, struct rpc_timeout *to) |
1da177e4 | 906 | { |
a246b010 | 907 | int result; |
1da177e4 | 908 | struct rpc_xprt *xprt; |
1da177e4 LT |
909 | struct rpc_rqst *req; |
910 | ||
1da177e4 LT |
911 | if ((xprt = kmalloc(sizeof(struct rpc_xprt), GFP_KERNEL)) == NULL) |
912 | return ERR_PTR(-ENOMEM); | |
913 | memset(xprt, 0, sizeof(*xprt)); /* Nnnngh! */ | |
1da177e4 LT |
914 | |
915 | xprt->addr = *ap; | |
a246b010 CL |
916 | |
917 | switch (proto) { | |
918 | case IPPROTO_UDP: | |
919 | result = xs_setup_udp(xprt, to); | |
920 | break; | |
921 | case IPPROTO_TCP: | |
922 | result = xs_setup_tcp(xprt, to); | |
923 | break; | |
924 | default: | |
925 | printk(KERN_ERR "RPC: unrecognized transport protocol: %d\n", | |
926 | proto); | |
927 | result = -EIO; | |
928 | break; | |
929 | } | |
930 | if (result) { | |
931 | kfree(xprt); | |
932 | return ERR_PTR(result); | |
1da177e4 | 933 | } |
a246b010 | 934 | |
4a0f8c04 | 935 | spin_lock_init(&xprt->transport_lock); |
5dc07727 | 936 | spin_lock_init(&xprt->reserve_lock); |
1da177e4 LT |
937 | |
938 | INIT_LIST_HEAD(&xprt->free); | |
939 | INIT_LIST_HEAD(&xprt->recv); | |
55aa4f58 | 940 | INIT_WORK(&xprt->task_cleanup, xprt_autoclose, xprt); |
1da177e4 LT |
941 | init_timer(&xprt->timer); |
942 | xprt->timer.function = xprt_init_autodisconnect; | |
943 | xprt->timer.data = (unsigned long) xprt; | |
944 | xprt->last_used = jiffies; | |
555ee3af | 945 | xprt->cwnd = RPC_INITCWND; |
1da177e4 LT |
946 | |
947 | rpc_init_wait_queue(&xprt->pending, "xprt_pending"); | |
948 | rpc_init_wait_queue(&xprt->sending, "xprt_sending"); | |
949 | rpc_init_wait_queue(&xprt->resend, "xprt_resend"); | |
950 | rpc_init_priority_wait_queue(&xprt->backlog, "xprt_backlog"); | |
951 | ||
952 | /* initialize free list */ | |
a246b010 | 953 | for (req = &xprt->slot[xprt->max_reqs-1]; req >= &xprt->slot[0]; req--) |
1da177e4 LT |
954 | list_add(&req->rq_list, &xprt->free); |
955 | ||
956 | xprt_init_xid(xprt); | |
957 | ||
1da177e4 LT |
958 | dprintk("RPC: created transport %p with %u slots\n", xprt, |
959 | xprt->max_reqs); | |
960 | ||
961 | return xprt; | |
962 | } | |
963 | ||
9903cd1c CL |
964 | /** |
965 | * xprt_create_proto - create an RPC client transport | |
966 | * @proto: requested transport protocol | |
967 | * @sap: remote peer's address | |
968 | * @to: timeout parameters for new transport | |
969 | * | |
1da177e4 | 970 | */ |
9903cd1c | 971 | struct rpc_xprt *xprt_create_proto(int proto, struct sockaddr_in *sap, struct rpc_timeout *to) |
1da177e4 LT |
972 | { |
973 | struct rpc_xprt *xprt; | |
974 | ||
975 | xprt = xprt_setup(proto, sap, to); | |
976 | if (IS_ERR(xprt)) | |
977 | dprintk("RPC: xprt_create_proto failed\n"); | |
978 | else | |
979 | dprintk("RPC: xprt_create_proto created xprt %p\n", xprt); | |
980 | return xprt; | |
981 | } | |
982 | ||
9903cd1c CL |
983 | /** |
984 | * xprt_destroy - destroy an RPC transport, killing off all requests. | |
985 | * @xprt: transport to destroy | |
986 | * | |
1da177e4 | 987 | */ |
9903cd1c | 988 | int xprt_destroy(struct rpc_xprt *xprt) |
1da177e4 LT |
989 | { |
990 | dprintk("RPC: destroying transport %p\n", xprt); | |
0065db32 TM |
991 | xprt->shutdown = 1; |
992 | del_timer_sync(&xprt->timer); | |
a246b010 | 993 | xprt->ops->destroy(xprt); |
1da177e4 LT |
994 | kfree(xprt); |
995 | ||
996 | return 0; | |
997 | } |