1 /*
2 * linux/net/sunrpc/svc_xprt.c
3 *
4 * Author: Tom Tucker <tom@opengridcomputing.com>
5 */
6
7 #include <linux/sched.h>
8 #include <linux/errno.h>
9 #include <linux/freezer.h>
10 #include <linux/kthread.h>
11 #include <net/sock.h>
12 #include <linux/sunrpc/stats.h>
13 #include <linux/sunrpc/svc_xprt.h>
14
15 #define RPCDBG_FACILITY RPCDBG_SVCXPRT
16
17 static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt);
18 static int svc_deferred_recv(struct svc_rqst *rqstp);
19 static struct cache_deferred_req *svc_defer(struct cache_req *req);
20 static void svc_age_temp_xprts(unsigned long closure);
21
22 /* apparently the "standard" is that clients close
23 * idle connections after 5 minutes, servers after
24 * 6 minutes
25 * http://www.connectathon.org/talks96/nfstcp.pdf
26 */
27 static int svc_conn_age_period = 6*60;
28
29 /* List of registered transport classes */
30 static DEFINE_SPINLOCK(svc_xprt_class_lock);
31 static LIST_HEAD(svc_xprt_class_list);
32
33 /* SMP locking strategy:
34 *
35 * svc_pool->sp_lock protects most of the fields of that pool.
36 * svc_serv->sv_lock protects sv_tempsocks, sv_permsocks, sv_tmpcnt.
37 * when both need to be taken (rare), svc_serv->sv_lock is first.
38 * BKL protects svc_serv->sv_nrthread.
39 * svc_sock->sk_lock protects the svc_sock->sk_deferred list
40 * and the ->sk_info_authunix cache.
41 *
42 * The XPT_BUSY bit in xprt->xpt_flags prevents a transport being
43 * enqueued multiply. During normal transport processing this bit
44 * is set by svc_xprt_enqueue and cleared by svc_xprt_received.
45 * Providers should not manipulate this bit directly.
46 *
47 * Some flags can be set to certain values at any time
48 * providing that certain rules are followed:
49 *
50 * XPT_CONN, XPT_DATA:
51 * - Can be set or cleared at any time.
52 * - After a set, svc_xprt_enqueue must be called to enqueue
53 * the transport for processing.
54 * - After a clear, the transport must be read/accepted.
55 * If this succeeds, it must be set again.
56 * XPT_CLOSE:
57 * - Can set at any time. It is never cleared.
58 * XPT_DEAD:
59 * - Can only be set while XPT_BUSY is held which ensures
60 * that no other thread will be using the transport or will
61 * try to set XPT_DEAD.
62 */
63
svc_reg_xprt_class(struct svc_xprt_class * xcl)64 int svc_reg_xprt_class(struct svc_xprt_class *xcl)
65 {
66 struct svc_xprt_class *cl;
67 int res = -EEXIST;
68
69 dprintk("svc: Adding svc transport class '%s'\n", xcl->xcl_name);
70
71 INIT_LIST_HEAD(&xcl->xcl_list);
72 spin_lock(&svc_xprt_class_lock);
73 /* Make sure there isn't already a class with the same name */
74 list_for_each_entry(cl, &svc_xprt_class_list, xcl_list) {
75 if (strcmp(xcl->xcl_name, cl->xcl_name) == 0)
76 goto out;
77 }
78 list_add_tail(&xcl->xcl_list, &svc_xprt_class_list);
79 res = 0;
80 out:
81 spin_unlock(&svc_xprt_class_lock);
82 return res;
83 }
84 EXPORT_SYMBOL_GPL(svc_reg_xprt_class);
85
svc_unreg_xprt_class(struct svc_xprt_class * xcl)86 void svc_unreg_xprt_class(struct svc_xprt_class *xcl)
87 {
88 dprintk("svc: Removing svc transport class '%s'\n", xcl->xcl_name);
89 spin_lock(&svc_xprt_class_lock);
90 list_del_init(&xcl->xcl_list);
91 spin_unlock(&svc_xprt_class_lock);
92 }
93 EXPORT_SYMBOL_GPL(svc_unreg_xprt_class);
94
95 /*
96 * Format the transport list for printing
97 */
svc_print_xprts(char * buf,int maxlen)98 int svc_print_xprts(char *buf, int maxlen)
99 {
100 struct list_head *le;
101 char tmpstr[80];
102 int len = 0;
103 buf[0] = '\0';
104
105 spin_lock(&svc_xprt_class_lock);
106 list_for_each(le, &svc_xprt_class_list) {
107 int slen;
108 struct svc_xprt_class *xcl =
109 list_entry(le, struct svc_xprt_class, xcl_list);
110
111 sprintf(tmpstr, "%s %d\n", xcl->xcl_name, xcl->xcl_max_payload);
112 slen = strlen(tmpstr);
113 if (len + slen > maxlen)
114 break;
115 len += slen;
116 strcat(buf, tmpstr);
117 }
118 spin_unlock(&svc_xprt_class_lock);
119
120 return len;
121 }
122
svc_xprt_free(struct kref * kref)123 static void svc_xprt_free(struct kref *kref)
124 {
125 struct svc_xprt *xprt =
126 container_of(kref, struct svc_xprt, xpt_ref);
127 struct module *owner = xprt->xpt_class->xcl_owner;
128 if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags)
129 && xprt->xpt_auth_cache != NULL)
130 svcauth_unix_info_release(xprt->xpt_auth_cache);
131 xprt->xpt_ops->xpo_free(xprt);
132 module_put(owner);
133 }
134
svc_xprt_put(struct svc_xprt * xprt)135 void svc_xprt_put(struct svc_xprt *xprt)
136 {
137 kref_put(&xprt->xpt_ref, svc_xprt_free);
138 }
139 EXPORT_SYMBOL_GPL(svc_xprt_put);
140
141 /*
142 * Called by transport drivers to initialize the transport independent
143 * portion of the transport instance.
144 */
svc_xprt_init(struct svc_xprt_class * xcl,struct svc_xprt * xprt,struct svc_serv * serv)145 void svc_xprt_init(struct svc_xprt_class *xcl, struct svc_xprt *xprt,
146 struct svc_serv *serv)
147 {
148 memset(xprt, 0, sizeof(*xprt));
149 xprt->xpt_class = xcl;
150 xprt->xpt_ops = xcl->xcl_ops;
151 kref_init(&xprt->xpt_ref);
152 xprt->xpt_server = serv;
153 INIT_LIST_HEAD(&xprt->xpt_list);
154 INIT_LIST_HEAD(&xprt->xpt_ready);
155 INIT_LIST_HEAD(&xprt->xpt_deferred);
156 mutex_init(&xprt->xpt_mutex);
157 spin_lock_init(&xprt->xpt_lock);
158 set_bit(XPT_BUSY, &xprt->xpt_flags);
159 }
160 EXPORT_SYMBOL_GPL(svc_xprt_init);
161
__svc_xpo_create(struct svc_xprt_class * xcl,struct svc_serv * serv,unsigned short port,int flags)162 static struct svc_xprt *__svc_xpo_create(struct svc_xprt_class *xcl,
163 struct svc_serv *serv,
164 unsigned short port, int flags)
165 {
166 struct sockaddr_in sin = {
167 .sin_family = AF_INET,
168 .sin_addr.s_addr = htonl(INADDR_ANY),
169 .sin_port = htons(port),
170 };
171 struct sockaddr_in6 sin6 = {
172 .sin6_family = AF_INET6,
173 .sin6_addr = IN6ADDR_ANY_INIT,
174 .sin6_port = htons(port),
175 };
176 struct sockaddr *sap;
177 size_t len;
178
179 switch (serv->sv_family) {
180 case AF_INET:
181 sap = (struct sockaddr *)&sin;
182 len = sizeof(sin);
183 break;
184 case AF_INET6:
185 sap = (struct sockaddr *)&sin6;
186 len = sizeof(sin6);
187 break;
188 default:
189 return ERR_PTR(-EAFNOSUPPORT);
190 }
191
192 return xcl->xcl_ops->xpo_create(serv, sap, len, flags);
193 }
194
svc_create_xprt(struct svc_serv * serv,char * xprt_name,unsigned short port,int flags)195 int svc_create_xprt(struct svc_serv *serv, char *xprt_name, unsigned short port,
196 int flags)
197 {
198 struct svc_xprt_class *xcl;
199
200 dprintk("svc: creating transport %s[%d]\n", xprt_name, port);
201 spin_lock(&svc_xprt_class_lock);
202 list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
203 struct svc_xprt *newxprt;
204
205 if (strcmp(xprt_name, xcl->xcl_name))
206 continue;
207
208 if (!try_module_get(xcl->xcl_owner))
209 goto err;
210
211 spin_unlock(&svc_xprt_class_lock);
212 newxprt = __svc_xpo_create(xcl, serv, port, flags);
213 if (IS_ERR(newxprt)) {
214 module_put(xcl->xcl_owner);
215 return PTR_ERR(newxprt);
216 }
217
218 clear_bit(XPT_TEMP, &newxprt->xpt_flags);
219 spin_lock_bh(&serv->sv_lock);
220 list_add(&newxprt->xpt_list, &serv->sv_permsocks);
221 spin_unlock_bh(&serv->sv_lock);
222 clear_bit(XPT_BUSY, &newxprt->xpt_flags);
223 return svc_xprt_local_port(newxprt);
224 }
225 err:
226 spin_unlock(&svc_xprt_class_lock);
227 dprintk("svc: transport %s not found\n", xprt_name);
228 return -ENOENT;
229 }
230 EXPORT_SYMBOL_GPL(svc_create_xprt);
231
232 /*
233 * Copy the local and remote xprt addresses to the rqstp structure
234 */
svc_xprt_copy_addrs(struct svc_rqst * rqstp,struct svc_xprt * xprt)235 void svc_xprt_copy_addrs(struct svc_rqst *rqstp, struct svc_xprt *xprt)
236 {
237 struct sockaddr *sin;
238
239 memcpy(&rqstp->rq_addr, &xprt->xpt_remote, xprt->xpt_remotelen);
240 rqstp->rq_addrlen = xprt->xpt_remotelen;
241
242 /*
243 * Destination address in request is needed for binding the
244 * source address in RPC replies/callbacks later.
245 */
246 sin = (struct sockaddr *)&xprt->xpt_local;
247 switch (sin->sa_family) {
248 case AF_INET:
249 rqstp->rq_daddr.addr = ((struct sockaddr_in *)sin)->sin_addr;
250 break;
251 case AF_INET6:
252 rqstp->rq_daddr.addr6 = ((struct sockaddr_in6 *)sin)->sin6_addr;
253 break;
254 }
255 }
256 EXPORT_SYMBOL_GPL(svc_xprt_copy_addrs);
257
258 /**
259 * svc_print_addr - Format rq_addr field for printing
260 * @rqstp: svc_rqst struct containing address to print
261 * @buf: target buffer for formatted address
262 * @len: length of target buffer
263 *
264 */
svc_print_addr(struct svc_rqst * rqstp,char * buf,size_t len)265 char *svc_print_addr(struct svc_rqst *rqstp, char *buf, size_t len)
266 {
267 return __svc_print_addr(svc_addr(rqstp), buf, len);
268 }
269 EXPORT_SYMBOL_GPL(svc_print_addr);
270
271 /*
272 * Queue up an idle server thread. Must have pool->sp_lock held.
273 * Note: this is really a stack rather than a queue, so that we only
274 * use as many different threads as we need, and the rest don't pollute
275 * the cache.
276 */
svc_thread_enqueue(struct svc_pool * pool,struct svc_rqst * rqstp)277 static void svc_thread_enqueue(struct svc_pool *pool, struct svc_rqst *rqstp)
278 {
279 list_add(&rqstp->rq_list, &pool->sp_threads);
280 }
281
282 /*
283 * Dequeue an nfsd thread. Must have pool->sp_lock held.
284 */
svc_thread_dequeue(struct svc_pool * pool,struct svc_rqst * rqstp)285 static void svc_thread_dequeue(struct svc_pool *pool, struct svc_rqst *rqstp)
286 {
287 list_del(&rqstp->rq_list);
288 }
289
290 /*
291 * Queue up a transport with data pending. If there are idle nfsd
292 * processes, wake 'em up.
293 *
294 */
svc_xprt_enqueue(struct svc_xprt * xprt)295 void svc_xprt_enqueue(struct svc_xprt *xprt)
296 {
297 struct svc_serv *serv = xprt->xpt_server;
298 struct svc_pool *pool;
299 struct svc_rqst *rqstp;
300 int cpu;
301
302 if (!(xprt->xpt_flags &
303 ((1<<XPT_CONN)|(1<<XPT_DATA)|(1<<XPT_CLOSE)|(1<<XPT_DEFERRED))))
304 return;
305
306 cpu = get_cpu();
307 pool = svc_pool_for_cpu(xprt->xpt_server, cpu);
308 put_cpu();
309
310 spin_lock_bh(&pool->sp_lock);
311
312 if (!list_empty(&pool->sp_threads) &&
313 !list_empty(&pool->sp_sockets))
314 printk(KERN_ERR
315 "svc_xprt_enqueue: "
316 "threads and transports both waiting??\n");
317
318 if (test_bit(XPT_DEAD, &xprt->xpt_flags)) {
319 /* Don't enqueue dead transports */
320 dprintk("svc: transport %p is dead, not enqueued\n", xprt);
321 goto out_unlock;
322 }
323
324 /* Mark transport as busy. It will remain in this state until
325 * the provider calls svc_xprt_received. We update XPT_BUSY
326 * atomically because it also guards against trying to enqueue
327 * the transport twice.
328 */
329 if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags)) {
330 /* Don't enqueue transport while already enqueued */
331 dprintk("svc: transport %p busy, not enqueued\n", xprt);
332 goto out_unlock;
333 }
334 BUG_ON(xprt->xpt_pool != NULL);
335 xprt->xpt_pool = pool;
336
337 /* Handle pending connection */
338 if (test_bit(XPT_CONN, &xprt->xpt_flags))
339 goto process;
340
341 /* Handle close in-progress */
342 if (test_bit(XPT_CLOSE, &xprt->xpt_flags))
343 goto process;
344
345 /* Check if we have space to reply to a request */
346 if (!xprt->xpt_ops->xpo_has_wspace(xprt)) {
347 /* Don't enqueue while not enough space for reply */
348 dprintk("svc: no write space, transport %p not enqueued\n",
349 xprt);
350 xprt->xpt_pool = NULL;
351 clear_bit(XPT_BUSY, &xprt->xpt_flags);
352 goto out_unlock;
353 }
354
355 process:
356 if (!list_empty(&pool->sp_threads)) {
357 rqstp = list_entry(pool->sp_threads.next,
358 struct svc_rqst,
359 rq_list);
360 dprintk("svc: transport %p served by daemon %p\n",
361 xprt, rqstp);
362 svc_thread_dequeue(pool, rqstp);
363 if (rqstp->rq_xprt)
364 printk(KERN_ERR
365 "svc_xprt_enqueue: server %p, rq_xprt=%p!\n",
366 rqstp, rqstp->rq_xprt);
367 rqstp->rq_xprt = xprt;
368 svc_xprt_get(xprt);
369 rqstp->rq_reserved = serv->sv_max_mesg;
370 atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
371 BUG_ON(xprt->xpt_pool != pool);
372 wake_up(&rqstp->rq_wait);
373 } else {
374 dprintk("svc: transport %p put into queue\n", xprt);
375 list_add_tail(&xprt->xpt_ready, &pool->sp_sockets);
376 BUG_ON(xprt->xpt_pool != pool);
377 }
378
379 out_unlock:
380 spin_unlock_bh(&pool->sp_lock);
381 }
382 EXPORT_SYMBOL_GPL(svc_xprt_enqueue);
383
384 /*
385 * Dequeue the first transport. Must be called with the pool->sp_lock held.
386 */
svc_xprt_dequeue(struct svc_pool * pool)387 static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool)
388 {
389 struct svc_xprt *xprt;
390
391 if (list_empty(&pool->sp_sockets))
392 return NULL;
393
394 xprt = list_entry(pool->sp_sockets.next,
395 struct svc_xprt, xpt_ready);
396 list_del_init(&xprt->xpt_ready);
397
398 dprintk("svc: transport %p dequeued, inuse=%d\n",
399 xprt, atomic_read(&xprt->xpt_ref.refcount));
400
401 return xprt;
402 }
403
404 /*
405 * svc_xprt_received conditionally queues the transport for processing
406 * by another thread. The caller must hold the XPT_BUSY bit and must
407 * not thereafter touch transport data.
408 *
409 * Note: XPT_DATA only gets cleared when a read-attempt finds no (or
410 * insufficient) data.
411 */
svc_xprt_received(struct svc_xprt * xprt)412 void svc_xprt_received(struct svc_xprt *xprt)
413 {
414 BUG_ON(!test_bit(XPT_BUSY, &xprt->xpt_flags));
415 xprt->xpt_pool = NULL;
416 clear_bit(XPT_BUSY, &xprt->xpt_flags);
417 svc_xprt_enqueue(xprt);
418 }
419 EXPORT_SYMBOL_GPL(svc_xprt_received);
420
421 /**
422 * svc_reserve - change the space reserved for the reply to a request.
423 * @rqstp: The request in question
424 * @space: new max space to reserve
425 *
426 * Each request reserves some space on the output queue of the transport
427 * to make sure the reply fits. This function reduces that reserved
428 * space to be the amount of space used already, plus @space.
429 *
430 */
svc_reserve(struct svc_rqst * rqstp,int space)431 void svc_reserve(struct svc_rqst *rqstp, int space)
432 {
433 space += rqstp->rq_res.head[0].iov_len;
434
435 if (space < rqstp->rq_reserved) {
436 struct svc_xprt *xprt = rqstp->rq_xprt;
437 atomic_sub((rqstp->rq_reserved - space), &xprt->xpt_reserved);
438 rqstp->rq_reserved = space;
439
440 svc_xprt_enqueue(xprt);
441 }
442 }
443 EXPORT_SYMBOL_GPL(svc_reserve);
444
svc_xprt_release(struct svc_rqst * rqstp)445 static void svc_xprt_release(struct svc_rqst *rqstp)
446 {
447 struct svc_xprt *xprt = rqstp->rq_xprt;
448
449 rqstp->rq_xprt->xpt_ops->xpo_release_rqst(rqstp);
450
451 kfree(rqstp->rq_deferred);
452 rqstp->rq_deferred = NULL;
453
454 svc_free_res_pages(rqstp);
455 rqstp->rq_res.page_len = 0;
456 rqstp->rq_res.page_base = 0;
457
458 /* Reset response buffer and release
459 * the reservation.
460 * But first, check that enough space was reserved
461 * for the reply, otherwise we have a bug!
462 */
463 if ((rqstp->rq_res.len) > rqstp->rq_reserved)
464 printk(KERN_ERR "RPC request reserved %d but used %d\n",
465 rqstp->rq_reserved,
466 rqstp->rq_res.len);
467
468 rqstp->rq_res.head[0].iov_len = 0;
469 svc_reserve(rqstp, 0);
470 rqstp->rq_xprt = NULL;
471
472 svc_xprt_put(xprt);
473 }
474
475 /*
476 * External function to wake up a server waiting for data
477 * This really only makes sense for services like lockd
478 * which have exactly one thread anyway.
479 */
svc_wake_up(struct svc_serv * serv)480 void svc_wake_up(struct svc_serv *serv)
481 {
482 struct svc_rqst *rqstp;
483 unsigned int i;
484 struct svc_pool *pool;
485
486 for (i = 0; i < serv->sv_nrpools; i++) {
487 pool = &serv->sv_pools[i];
488
489 spin_lock_bh(&pool->sp_lock);
490 if (!list_empty(&pool->sp_threads)) {
491 rqstp = list_entry(pool->sp_threads.next,
492 struct svc_rqst,
493 rq_list);
494 dprintk("svc: daemon %p woken up.\n", rqstp);
495 /*
496 svc_thread_dequeue(pool, rqstp);
497 rqstp->rq_xprt = NULL;
498 */
499 wake_up(&rqstp->rq_wait);
500 }
501 spin_unlock_bh(&pool->sp_lock);
502 }
503 }
504 EXPORT_SYMBOL_GPL(svc_wake_up);
505
svc_port_is_privileged(struct sockaddr * sin)506 int svc_port_is_privileged(struct sockaddr *sin)
507 {
508 switch (sin->sa_family) {
509 case AF_INET:
510 return ntohs(((struct sockaddr_in *)sin)->sin_port)
511 < PROT_SOCK;
512 case AF_INET6:
513 return ntohs(((struct sockaddr_in6 *)sin)->sin6_port)
514 < PROT_SOCK;
515 default:
516 return 0;
517 }
518 }
519
520 /*
521 * Make sure that we don't have too many active connections. If we have,
522 * something must be dropped. It's not clear what will happen if we allow
523 * "too many" connections, but when dealing with network-facing software,
524 * we have to code defensively. Here we do that by imposing hard limits.
525 *
526 * There's no point in trying to do random drop here for DoS
527 * prevention. The NFS clients does 1 reconnect in 15 seconds. An
528 * attacker can easily beat that.
529 *
530 * The only somewhat efficient mechanism would be if drop old
531 * connections from the same IP first. But right now we don't even
532 * record the client IP in svc_sock.
533 *
534 * single-threaded services that expect a lot of clients will probably
535 * need to set sv_maxconn to override the default value which is based
536 * on the number of threads
537 */
svc_check_conn_limits(struct svc_serv * serv)538 static void svc_check_conn_limits(struct svc_serv *serv)
539 {
540 unsigned int limit = serv->sv_maxconn ? serv->sv_maxconn :
541 (serv->sv_nrthreads+3) * 20;
542
543 if (serv->sv_tmpcnt > limit) {
544 struct svc_xprt *xprt = NULL;
545 spin_lock_bh(&serv->sv_lock);
546 if (!list_empty(&serv->sv_tempsocks)) {
547 if (net_ratelimit()) {
548 /* Try to help the admin */
549 printk(KERN_NOTICE "%s: too many open "
550 "connections, consider increasing %s\n",
551 serv->sv_name, serv->sv_maxconn ?
552 "the max number of connections." :
553 "the number of threads.");
554 }
555 /*
556 * Always select the oldest connection. It's not fair,
557 * but so is life
558 */
559 xprt = list_entry(serv->sv_tempsocks.prev,
560 struct svc_xprt,
561 xpt_list);
562 set_bit(XPT_CLOSE, &xprt->xpt_flags);
563 svc_xprt_get(xprt);
564 }
565 spin_unlock_bh(&serv->sv_lock);
566
567 if (xprt) {
568 svc_xprt_enqueue(xprt);
569 svc_xprt_put(xprt);
570 }
571 }
572 }
573
574 /*
575 * Receive the next request on any transport. This code is carefully
576 * organised not to touch any cachelines in the shared svc_serv
577 * structure, only cachelines in the local svc_pool.
578 */
svc_recv(struct svc_rqst * rqstp,long timeout)579 int svc_recv(struct svc_rqst *rqstp, long timeout)
580 {
581 struct svc_xprt *xprt = NULL;
582 struct svc_serv *serv = rqstp->rq_server;
583 struct svc_pool *pool = rqstp->rq_pool;
584 int len, i;
585 int pages;
586 struct xdr_buf *arg;
587 DECLARE_WAITQUEUE(wait, current);
588
589 dprintk("svc: server %p waiting for data (to = %ld)\n",
590 rqstp, timeout);
591
592 if (rqstp->rq_xprt)
593 printk(KERN_ERR
594 "svc_recv: service %p, transport not NULL!\n",
595 rqstp);
596 if (waitqueue_active(&rqstp->rq_wait))
597 printk(KERN_ERR
598 "svc_recv: service %p, wait queue active!\n",
599 rqstp);
600
601 /* now allocate needed pages. If we get a failure, sleep briefly */
602 pages = (serv->sv_max_mesg + PAGE_SIZE) / PAGE_SIZE;
603 for (i = 0; i < pages ; i++)
604 while (rqstp->rq_pages[i] == NULL) {
605 struct page *p = alloc_page(GFP_KERNEL);
606 if (!p) {
607 set_current_state(TASK_INTERRUPTIBLE);
608 if (signalled() || kthread_should_stop()) {
609 set_current_state(TASK_RUNNING);
610 return -EINTR;
611 }
612 schedule_timeout(msecs_to_jiffies(500));
613 }
614 rqstp->rq_pages[i] = p;
615 }
616 rqstp->rq_pages[i++] = NULL; /* this might be seen in nfs_read_actor */
617 BUG_ON(pages >= RPCSVC_MAXPAGES);
618
619 /* Make arg->head point to first page and arg->pages point to rest */
620 arg = &rqstp->rq_arg;
621 arg->head[0].iov_base = page_address(rqstp->rq_pages[0]);
622 arg->head[0].iov_len = PAGE_SIZE;
623 arg->pages = rqstp->rq_pages + 1;
624 arg->page_base = 0;
625 /* save at least one page for response */
626 arg->page_len = (pages-2)*PAGE_SIZE;
627 arg->len = (pages-1)*PAGE_SIZE;
628 arg->tail[0].iov_len = 0;
629
630 try_to_freeze();
631 cond_resched();
632 if (signalled() || kthread_should_stop())
633 return -EINTR;
634
635 spin_lock_bh(&pool->sp_lock);
636 xprt = svc_xprt_dequeue(pool);
637 if (xprt) {
638 rqstp->rq_xprt = xprt;
639 svc_xprt_get(xprt);
640 rqstp->rq_reserved = serv->sv_max_mesg;
641 atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
642 } else {
643 /* No data pending. Go to sleep */
644 svc_thread_enqueue(pool, rqstp);
645
646 /*
647 * We have to be able to interrupt this wait
648 * to bring down the daemons ...
649 */
650 set_current_state(TASK_INTERRUPTIBLE);
651
652 /*
653 * checking kthread_should_stop() here allows us to avoid
654 * locking and signalling when stopping kthreads that call
655 * svc_recv. If the thread has already been woken up, then
656 * we can exit here without sleeping. If not, then it
657 * it'll be woken up quickly during the schedule_timeout
658 */
659 if (kthread_should_stop()) {
660 set_current_state(TASK_RUNNING);
661 spin_unlock_bh(&pool->sp_lock);
662 return -EINTR;
663 }
664
665 add_wait_queue(&rqstp->rq_wait, &wait);
666 spin_unlock_bh(&pool->sp_lock);
667
668 schedule_timeout(timeout);
669
670 try_to_freeze();
671
672 spin_lock_bh(&pool->sp_lock);
673 remove_wait_queue(&rqstp->rq_wait, &wait);
674
675 xprt = rqstp->rq_xprt;
676 if (!xprt) {
677 svc_thread_dequeue(pool, rqstp);
678 spin_unlock_bh(&pool->sp_lock);
679 dprintk("svc: server %p, no data yet\n", rqstp);
680 if (signalled() || kthread_should_stop())
681 return -EINTR;
682 else
683 return -EAGAIN;
684 }
685 }
686 spin_unlock_bh(&pool->sp_lock);
687
688 len = 0;
689 if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) {
690 dprintk("svc_recv: found XPT_CLOSE\n");
691 svc_delete_xprt(xprt);
692 } else if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) {
693 struct svc_xprt *newxpt;
694 newxpt = xprt->xpt_ops->xpo_accept(xprt);
695 if (newxpt) {
696 /*
697 * We know this module_get will succeed because the
698 * listener holds a reference too
699 */
700 __module_get(newxpt->xpt_class->xcl_owner);
701 svc_check_conn_limits(xprt->xpt_server);
702 spin_lock_bh(&serv->sv_lock);
703 set_bit(XPT_TEMP, &newxpt->xpt_flags);
704 list_add(&newxpt->xpt_list, &serv->sv_tempsocks);
705 serv->sv_tmpcnt++;
706 if (serv->sv_temptimer.function == NULL) {
707 /* setup timer to age temp transports */
708 setup_timer(&serv->sv_temptimer,
709 svc_age_temp_xprts,
710 (unsigned long)serv);
711 mod_timer(&serv->sv_temptimer,
712 jiffies + svc_conn_age_period * HZ);
713 }
714 spin_unlock_bh(&serv->sv_lock);
715 svc_xprt_received(newxpt);
716 }
717 svc_xprt_received(xprt);
718 } else {
719 dprintk("svc: server %p, pool %u, transport %p, inuse=%d\n",
720 rqstp, pool->sp_id, xprt,
721 atomic_read(&xprt->xpt_ref.refcount));
722 rqstp->rq_deferred = svc_deferred_dequeue(xprt);
723 if (rqstp->rq_deferred) {
724 svc_xprt_received(xprt);
725 len = svc_deferred_recv(rqstp);
726 } else
727 len = xprt->xpt_ops->xpo_recvfrom(rqstp);
728 dprintk("svc: got len=%d\n", len);
729 }
730
731 /* No data, incomplete (TCP) read, or accept() */
732 if (len == 0 || len == -EAGAIN) {
733 rqstp->rq_res.len = 0;
734 svc_xprt_release(rqstp);
735 return -EAGAIN;
736 }
737 clear_bit(XPT_OLD, &xprt->xpt_flags);
738
739 rqstp->rq_secure = svc_port_is_privileged(svc_addr(rqstp));
740 rqstp->rq_chandle.defer = svc_defer;
741
742 if (serv->sv_stats)
743 serv->sv_stats->netcnt++;
744 return len;
745 }
746 EXPORT_SYMBOL_GPL(svc_recv);
747
748 /*
749 * Drop request
750 */
svc_drop(struct svc_rqst * rqstp)751 void svc_drop(struct svc_rqst *rqstp)
752 {
753 dprintk("svc: xprt %p dropped request\n", rqstp->rq_xprt);
754 svc_xprt_release(rqstp);
755 }
756 EXPORT_SYMBOL_GPL(svc_drop);
757
758 /*
759 * Return reply to client.
760 */
svc_send(struct svc_rqst * rqstp)761 int svc_send(struct svc_rqst *rqstp)
762 {
763 struct svc_xprt *xprt;
764 int len;
765 struct xdr_buf *xb;
766
767 xprt = rqstp->rq_xprt;
768 if (!xprt)
769 return -EFAULT;
770
771 /* release the receive skb before sending the reply */
772 rqstp->rq_xprt->xpt_ops->xpo_release_rqst(rqstp);
773
774 /* calculate over-all length */
775 xb = &rqstp->rq_res;
776 xb->len = xb->head[0].iov_len +
777 xb->page_len +
778 xb->tail[0].iov_len;
779
780 /* Grab mutex to serialize outgoing data. */
781 mutex_lock(&xprt->xpt_mutex);
782 if (test_bit(XPT_DEAD, &xprt->xpt_flags))
783 len = -ENOTCONN;
784 else
785 len = xprt->xpt_ops->xpo_sendto(rqstp);
786 mutex_unlock(&xprt->xpt_mutex);
787 svc_xprt_release(rqstp);
788
789 if (len == -ECONNREFUSED || len == -ENOTCONN || len == -EAGAIN)
790 return 0;
791 return len;
792 }
793
794 /*
795 * Timer function to close old temporary transports, using
796 * a mark-and-sweep algorithm.
797 */
svc_age_temp_xprts(unsigned long closure)798 static void svc_age_temp_xprts(unsigned long closure)
799 {
800 struct svc_serv *serv = (struct svc_serv *)closure;
801 struct svc_xprt *xprt;
802 struct list_head *le, *next;
803 LIST_HEAD(to_be_aged);
804
805 dprintk("svc_age_temp_xprts\n");
806
807 if (!spin_trylock_bh(&serv->sv_lock)) {
808 /* busy, try again 1 sec later */
809 dprintk("svc_age_temp_xprts: busy\n");
810 mod_timer(&serv->sv_temptimer, jiffies + HZ);
811 return;
812 }
813
814 list_for_each_safe(le, next, &serv->sv_tempsocks) {
815 xprt = list_entry(le, struct svc_xprt, xpt_list);
816
817 /* First time through, just mark it OLD. Second time
818 * through, close it. */
819 if (!test_and_set_bit(XPT_OLD, &xprt->xpt_flags))
820 continue;
821 if (atomic_read(&xprt->xpt_ref.refcount) > 1
822 || test_bit(XPT_BUSY, &xprt->xpt_flags))
823 continue;
824 svc_xprt_get(xprt);
825 list_move(le, &to_be_aged);
826 set_bit(XPT_CLOSE, &xprt->xpt_flags);
827 set_bit(XPT_DETACHED, &xprt->xpt_flags);
828 }
829 spin_unlock_bh(&serv->sv_lock);
830
831 while (!list_empty(&to_be_aged)) {
832 le = to_be_aged.next;
833 /* fiddling the xpt_list node is safe 'cos we're XPT_DETACHED */
834 list_del_init(le);
835 xprt = list_entry(le, struct svc_xprt, xpt_list);
836
837 dprintk("queuing xprt %p for closing\n", xprt);
838
839 /* a thread will dequeue and close it soon */
840 svc_xprt_enqueue(xprt);
841 svc_xprt_put(xprt);
842 }
843
844 mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ);
845 }
846
847 /*
848 * Remove a dead transport
849 */
svc_delete_xprt(struct svc_xprt * xprt)850 void svc_delete_xprt(struct svc_xprt *xprt)
851 {
852 struct svc_serv *serv = xprt->xpt_server;
853 struct svc_deferred_req *dr;
854
855 /* Only do this once */
856 if (test_and_set_bit(XPT_DEAD, &xprt->xpt_flags))
857 return;
858
859 dprintk("svc: svc_delete_xprt(%p)\n", xprt);
860 xprt->xpt_ops->xpo_detach(xprt);
861
862 spin_lock_bh(&serv->sv_lock);
863 if (!test_and_set_bit(XPT_DETACHED, &xprt->xpt_flags))
864 list_del_init(&xprt->xpt_list);
865 /*
866 * We used to delete the transport from whichever list
867 * it's sk_xprt.xpt_ready node was on, but we don't actually
868 * need to. This is because the only time we're called
869 * while still attached to a queue, the queue itself
870 * is about to be destroyed (in svc_destroy).
871 */
872 if (test_bit(XPT_TEMP, &xprt->xpt_flags))
873 serv->sv_tmpcnt--;
874
875 for (dr = svc_deferred_dequeue(xprt); dr;
876 dr = svc_deferred_dequeue(xprt)) {
877 svc_xprt_put(xprt);
878 kfree(dr);
879 }
880
881 svc_xprt_put(xprt);
882 spin_unlock_bh(&serv->sv_lock);
883 }
884
svc_close_xprt(struct svc_xprt * xprt)885 void svc_close_xprt(struct svc_xprt *xprt)
886 {
887 set_bit(XPT_CLOSE, &xprt->xpt_flags);
888 if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
889 /* someone else will have to effect the close */
890 return;
891
892 svc_xprt_get(xprt);
893 svc_delete_xprt(xprt);
894 clear_bit(XPT_BUSY, &xprt->xpt_flags);
895 svc_xprt_put(xprt);
896 }
897 EXPORT_SYMBOL_GPL(svc_close_xprt);
898
svc_close_all(struct list_head * xprt_list)899 void svc_close_all(struct list_head *xprt_list)
900 {
901 struct svc_xprt *xprt;
902 struct svc_xprt *tmp;
903
904 list_for_each_entry_safe(xprt, tmp, xprt_list, xpt_list) {
905 set_bit(XPT_CLOSE, &xprt->xpt_flags);
906 if (test_bit(XPT_BUSY, &xprt->xpt_flags)) {
907 /* Waiting to be processed, but no threads left,
908 * So just remove it from the waiting list
909 */
910 list_del_init(&xprt->xpt_ready);
911 clear_bit(XPT_BUSY, &xprt->xpt_flags);
912 }
913 svc_close_xprt(xprt);
914 }
915 }
916
917 /*
918 * Handle defer and revisit of requests
919 */
920
svc_revisit(struct cache_deferred_req * dreq,int too_many)921 static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
922 {
923 struct svc_deferred_req *dr =
924 container_of(dreq, struct svc_deferred_req, handle);
925 struct svc_xprt *xprt = dr->xprt;
926
927 spin_lock(&xprt->xpt_lock);
928 set_bit(XPT_DEFERRED, &xprt->xpt_flags);
929 if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) {
930 spin_unlock(&xprt->xpt_lock);
931 dprintk("revisit canceled\n");
932 svc_xprt_put(xprt);
933 kfree(dr);
934 return;
935 }
936 dprintk("revisit queued\n");
937 dr->xprt = NULL;
938 list_add(&dr->handle.recent, &xprt->xpt_deferred);
939 spin_unlock(&xprt->xpt_lock);
940 svc_xprt_enqueue(xprt);
941 svc_xprt_put(xprt);
942 }
943
944 /*
945 * Save the request off for later processing. The request buffer looks
946 * like this:
947 *
948 * <xprt-header><rpc-header><rpc-pagelist><rpc-tail>
949 *
950 * This code can only handle requests that consist of an xprt-header
951 * and rpc-header.
952 */
svc_defer(struct cache_req * req)953 static struct cache_deferred_req *svc_defer(struct cache_req *req)
954 {
955 struct svc_rqst *rqstp = container_of(req, struct svc_rqst, rq_chandle);
956 struct svc_deferred_req *dr;
957
958 if (rqstp->rq_arg.page_len)
959 return NULL; /* if more than a page, give up FIXME */
960 if (rqstp->rq_deferred) {
961 dr = rqstp->rq_deferred;
962 rqstp->rq_deferred = NULL;
963 } else {
964 size_t skip;
965 size_t size;
966 /* FIXME maybe discard if size too large */
967 size = sizeof(struct svc_deferred_req) + rqstp->rq_arg.len;
968 dr = kmalloc(size, GFP_KERNEL);
969 if (dr == NULL)
970 return NULL;
971
972 dr->handle.owner = rqstp->rq_server;
973 dr->prot = rqstp->rq_prot;
974 memcpy(&dr->addr, &rqstp->rq_addr, rqstp->rq_addrlen);
975 dr->addrlen = rqstp->rq_addrlen;
976 dr->daddr = rqstp->rq_daddr;
977 dr->argslen = rqstp->rq_arg.len >> 2;
978 dr->xprt_hlen = rqstp->rq_xprt_hlen;
979
980 /* back up head to the start of the buffer and copy */
981 skip = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len;
982 memcpy(dr->args, rqstp->rq_arg.head[0].iov_base - skip,
983 dr->argslen << 2);
984 }
985 svc_xprt_get(rqstp->rq_xprt);
986 dr->xprt = rqstp->rq_xprt;
987
988 dr->handle.revisit = svc_revisit;
989 return &dr->handle;
990 }
991
992 /*
993 * recv data from a deferred request into an active one
994 */
svc_deferred_recv(struct svc_rqst * rqstp)995 static int svc_deferred_recv(struct svc_rqst *rqstp)
996 {
997 struct svc_deferred_req *dr = rqstp->rq_deferred;
998
999 /* setup iov_base past transport header */
1000 rqstp->rq_arg.head[0].iov_base = dr->args + (dr->xprt_hlen>>2);
1001 /* The iov_len does not include the transport header bytes */
1002 rqstp->rq_arg.head[0].iov_len = (dr->argslen<<2) - dr->xprt_hlen;
1003 rqstp->rq_arg.page_len = 0;
1004 /* The rq_arg.len includes the transport header bytes */
1005 rqstp->rq_arg.len = dr->argslen<<2;
1006 rqstp->rq_prot = dr->prot;
1007 memcpy(&rqstp->rq_addr, &dr->addr, dr->addrlen);
1008 rqstp->rq_addrlen = dr->addrlen;
1009 /* Save off transport header len in case we get deferred again */
1010 rqstp->rq_xprt_hlen = dr->xprt_hlen;
1011 rqstp->rq_daddr = dr->daddr;
1012 rqstp->rq_respages = rqstp->rq_pages;
1013 return (dr->argslen<<2) - dr->xprt_hlen;
1014 }
1015
1016
svc_deferred_dequeue(struct svc_xprt * xprt)1017 static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt)
1018 {
1019 struct svc_deferred_req *dr = NULL;
1020
1021 if (!test_bit(XPT_DEFERRED, &xprt->xpt_flags))
1022 return NULL;
1023 spin_lock(&xprt->xpt_lock);
1024 clear_bit(XPT_DEFERRED, &xprt->xpt_flags);
1025 if (!list_empty(&xprt->xpt_deferred)) {
1026 dr = list_entry(xprt->xpt_deferred.next,
1027 struct svc_deferred_req,
1028 handle.recent);
1029 list_del_init(&dr->handle.recent);
1030 set_bit(XPT_DEFERRED, &xprt->xpt_flags);
1031 }
1032 spin_unlock(&xprt->xpt_lock);
1033 return dr;
1034 }
1035
1036 /*
1037 * Return the transport instance pointer for the endpoint accepting
1038 * connections/peer traffic from the specified transport class,
1039 * address family and port.
1040 *
1041 * Specifying 0 for the address family or port is effectively a
1042 * wild-card, and will result in matching the first transport in the
1043 * service's list that has a matching class name.
1044 */
svc_find_xprt(struct svc_serv * serv,char * xcl_name,int af,int port)1045 struct svc_xprt *svc_find_xprt(struct svc_serv *serv, char *xcl_name,
1046 int af, int port)
1047 {
1048 struct svc_xprt *xprt;
1049 struct svc_xprt *found = NULL;
1050
1051 /* Sanity check the args */
1052 if (!serv || !xcl_name)
1053 return found;
1054
1055 spin_lock_bh(&serv->sv_lock);
1056 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1057 if (strcmp(xprt->xpt_class->xcl_name, xcl_name))
1058 continue;
1059 if (af != AF_UNSPEC && af != xprt->xpt_local.ss_family)
1060 continue;
1061 if (port && port != svc_xprt_local_port(xprt))
1062 continue;
1063 found = xprt;
1064 svc_xprt_get(xprt);
1065 break;
1066 }
1067 spin_unlock_bh(&serv->sv_lock);
1068 return found;
1069 }
1070 EXPORT_SYMBOL_GPL(svc_find_xprt);
1071
1072 /*
1073 * Format a buffer with a list of the active transports. A zero for
1074 * the buflen parameter disables target buffer overflow checking.
1075 */
svc_xprt_names(struct svc_serv * serv,char * buf,int buflen)1076 int svc_xprt_names(struct svc_serv *serv, char *buf, int buflen)
1077 {
1078 struct svc_xprt *xprt;
1079 char xprt_str[64];
1080 int totlen = 0;
1081 int len;
1082
1083 /* Sanity check args */
1084 if (!serv)
1085 return 0;
1086
1087 spin_lock_bh(&serv->sv_lock);
1088 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1089 len = snprintf(xprt_str, sizeof(xprt_str),
1090 "%s %d\n", xprt->xpt_class->xcl_name,
1091 svc_xprt_local_port(xprt));
1092 /* If the string was truncated, replace with error string */
1093 if (len >= sizeof(xprt_str))
1094 strcpy(xprt_str, "name-too-long\n");
1095 /* Don't overflow buffer */
1096 len = strlen(xprt_str);
1097 if (buflen && (len + totlen >= buflen))
1098 break;
1099 strcpy(buf+totlen, xprt_str);
1100 totlen += len;
1101 }
1102 spin_unlock_bh(&serv->sv_lock);
1103 return totlen;
1104 }
1105 EXPORT_SYMBOL_GPL(svc_xprt_names);
1106