Loading...
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/net/sunrpc/svc_xprt.c
4 *
5 * Author: Tom Tucker <tom@opengridcomputing.com>
6 */
7
8#include <linux/sched.h>
9#include <linux/errno.h>
10#include <linux/freezer.h>
11#include <linux/kthread.h>
12#include <linux/slab.h>
13#include <net/sock.h>
14#include <linux/sunrpc/addr.h>
15#include <linux/sunrpc/stats.h>
16#include <linux/sunrpc/svc_xprt.h>
17#include <linux/sunrpc/svcsock.h>
18#include <linux/sunrpc/xprt.h>
19#include <linux/module.h>
20#include <linux/netdevice.h>
21#include <trace/events/sunrpc.h>
22
23#define RPCDBG_FACILITY RPCDBG_SVCXPRT
24
25static unsigned int svc_rpc_per_connection_limit __read_mostly;
26module_param(svc_rpc_per_connection_limit, uint, 0644);
27
28
29static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt);
30static int svc_deferred_recv(struct svc_rqst *rqstp);
31static struct cache_deferred_req *svc_defer(struct cache_req *req);
32static void svc_age_temp_xprts(struct timer_list *t);
33static void svc_delete_xprt(struct svc_xprt *xprt);
34
35/* apparently the "standard" is that clients close
36 * idle connections after 5 minutes, servers after
37 * 6 minutes
38 * http://nfsv4bat.org/Documents/ConnectAThon/1996/nfstcp.pdf
39 */
40static int svc_conn_age_period = 6*60;
41
42/* List of registered transport classes */
43static DEFINE_SPINLOCK(svc_xprt_class_lock);
44static LIST_HEAD(svc_xprt_class_list);
45
46/* SMP locking strategy:
47 *
48 * svc_pool->sp_lock protects most of the fields of that pool.
49 * svc_serv->sv_lock protects sv_tempsocks, sv_permsocks, sv_tmpcnt.
50 * when both need to be taken (rare), svc_serv->sv_lock is first.
51 * The "service mutex" protects svc_serv->sv_nrthread.
52 * svc_sock->sk_lock protects the svc_sock->sk_deferred list
53 * and the ->sk_info_authunix cache.
54 *
55 * The XPT_BUSY bit in xprt->xpt_flags prevents a transport being
56 * enqueued multiply. During normal transport processing this bit
57 * is set by svc_xprt_enqueue and cleared by svc_xprt_received.
58 * Providers should not manipulate this bit directly.
59 *
60 * Some flags can be set to certain values at any time
61 * providing that certain rules are followed:
62 *
63 * XPT_CONN, XPT_DATA:
64 * - Can be set or cleared at any time.
65 * - After a set, svc_xprt_enqueue must be called to enqueue
66 * the transport for processing.
67 * - After a clear, the transport must be read/accepted.
68 * If this succeeds, it must be set again.
69 * XPT_CLOSE:
70 * - Can set at any time. It is never cleared.
71 * XPT_DEAD:
72 * - Can only be set while XPT_BUSY is held which ensures
73 * that no other thread will be using the transport or will
74 * try to set XPT_DEAD.
75 */
76int svc_reg_xprt_class(struct svc_xprt_class *xcl)
77{
78 struct svc_xprt_class *cl;
79 int res = -EEXIST;
80
81 dprintk("svc: Adding svc transport class '%s'\n", xcl->xcl_name);
82
83 INIT_LIST_HEAD(&xcl->xcl_list);
84 spin_lock(&svc_xprt_class_lock);
85 /* Make sure there isn't already a class with the same name */
86 list_for_each_entry(cl, &svc_xprt_class_list, xcl_list) {
87 if (strcmp(xcl->xcl_name, cl->xcl_name) == 0)
88 goto out;
89 }
90 list_add_tail(&xcl->xcl_list, &svc_xprt_class_list);
91 res = 0;
92out:
93 spin_unlock(&svc_xprt_class_lock);
94 return res;
95}
96EXPORT_SYMBOL_GPL(svc_reg_xprt_class);
97
98void svc_unreg_xprt_class(struct svc_xprt_class *xcl)
99{
100 dprintk("svc: Removing svc transport class '%s'\n", xcl->xcl_name);
101 spin_lock(&svc_xprt_class_lock);
102 list_del_init(&xcl->xcl_list);
103 spin_unlock(&svc_xprt_class_lock);
104}
105EXPORT_SYMBOL_GPL(svc_unreg_xprt_class);
106
107/*
108 * Format the transport list for printing
109 */
110int svc_print_xprts(char *buf, int maxlen)
111{
112 struct svc_xprt_class *xcl;
113 char tmpstr[80];
114 int len = 0;
115 buf[0] = '\0';
116
117 spin_lock(&svc_xprt_class_lock);
118 list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
119 int slen;
120
121 sprintf(tmpstr, "%s %d\n", xcl->xcl_name, xcl->xcl_max_payload);
122 slen = strlen(tmpstr);
123 if (len + slen > maxlen)
124 break;
125 len += slen;
126 strcat(buf, tmpstr);
127 }
128 spin_unlock(&svc_xprt_class_lock);
129
130 return len;
131}
132
133static void svc_xprt_free(struct kref *kref)
134{
135 struct svc_xprt *xprt =
136 container_of(kref, struct svc_xprt, xpt_ref);
137 struct module *owner = xprt->xpt_class->xcl_owner;
138 if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags))
139 svcauth_unix_info_release(xprt);
140 put_cred(xprt->xpt_cred);
141 put_net(xprt->xpt_net);
142 /* See comment on corresponding get in xs_setup_bc_tcp(): */
143 if (xprt->xpt_bc_xprt)
144 xprt_put(xprt->xpt_bc_xprt);
145 if (xprt->xpt_bc_xps)
146 xprt_switch_put(xprt->xpt_bc_xps);
147 xprt->xpt_ops->xpo_free(xprt);
148 module_put(owner);
149}
150
151void svc_xprt_put(struct svc_xprt *xprt)
152{
153 kref_put(&xprt->xpt_ref, svc_xprt_free);
154}
155EXPORT_SYMBOL_GPL(svc_xprt_put);
156
157/*
158 * Called by transport drivers to initialize the transport independent
159 * portion of the transport instance.
160 */
161void svc_xprt_init(struct net *net, struct svc_xprt_class *xcl,
162 struct svc_xprt *xprt, struct svc_serv *serv)
163{
164 memset(xprt, 0, sizeof(*xprt));
165 xprt->xpt_class = xcl;
166 xprt->xpt_ops = xcl->xcl_ops;
167 kref_init(&xprt->xpt_ref);
168 xprt->xpt_server = serv;
169 INIT_LIST_HEAD(&xprt->xpt_list);
170 INIT_LIST_HEAD(&xprt->xpt_ready);
171 INIT_LIST_HEAD(&xprt->xpt_deferred);
172 INIT_LIST_HEAD(&xprt->xpt_users);
173 mutex_init(&xprt->xpt_mutex);
174 spin_lock_init(&xprt->xpt_lock);
175 set_bit(XPT_BUSY, &xprt->xpt_flags);
176 xprt->xpt_net = get_net(net);
177 strcpy(xprt->xpt_remotebuf, "uninitialized");
178}
179EXPORT_SYMBOL_GPL(svc_xprt_init);
180
181static struct svc_xprt *__svc_xpo_create(struct svc_xprt_class *xcl,
182 struct svc_serv *serv,
183 struct net *net,
184 const int family,
185 const unsigned short port,
186 int flags)
187{
188 struct sockaddr_in sin = {
189 .sin_family = AF_INET,
190 .sin_addr.s_addr = htonl(INADDR_ANY),
191 .sin_port = htons(port),
192 };
193#if IS_ENABLED(CONFIG_IPV6)
194 struct sockaddr_in6 sin6 = {
195 .sin6_family = AF_INET6,
196 .sin6_addr = IN6ADDR_ANY_INIT,
197 .sin6_port = htons(port),
198 };
199#endif
200 struct sockaddr *sap;
201 size_t len;
202
203 switch (family) {
204 case PF_INET:
205 sap = (struct sockaddr *)&sin;
206 len = sizeof(sin);
207 break;
208#if IS_ENABLED(CONFIG_IPV6)
209 case PF_INET6:
210 sap = (struct sockaddr *)&sin6;
211 len = sizeof(sin6);
212 break;
213#endif
214 default:
215 return ERR_PTR(-EAFNOSUPPORT);
216 }
217
218 return xcl->xcl_ops->xpo_create(serv, net, sap, len, flags);
219}
220
221/*
222 * svc_xprt_received conditionally queues the transport for processing
223 * by another thread. The caller must hold the XPT_BUSY bit and must
224 * not thereafter touch transport data.
225 *
226 * Note: XPT_DATA only gets cleared when a read-attempt finds no (or
227 * insufficient) data.
228 */
229static void svc_xprt_received(struct svc_xprt *xprt)
230{
231 if (!test_bit(XPT_BUSY, &xprt->xpt_flags)) {
232 WARN_ONCE(1, "xprt=0x%p already busy!", xprt);
233 return;
234 }
235
236 /* As soon as we clear busy, the xprt could be closed and
237 * 'put', so we need a reference to call svc_enqueue_xprt with:
238 */
239 svc_xprt_get(xprt);
240 smp_mb__before_atomic();
241 clear_bit(XPT_BUSY, &xprt->xpt_flags);
242 xprt->xpt_server->sv_ops->svo_enqueue_xprt(xprt);
243 svc_xprt_put(xprt);
244}
245
246void svc_add_new_perm_xprt(struct svc_serv *serv, struct svc_xprt *new)
247{
248 clear_bit(XPT_TEMP, &new->xpt_flags);
249 spin_lock_bh(&serv->sv_lock);
250 list_add(&new->xpt_list, &serv->sv_permsocks);
251 spin_unlock_bh(&serv->sv_lock);
252 svc_xprt_received(new);
253}
254
255static int _svc_create_xprt(struct svc_serv *serv, const char *xprt_name,
256 struct net *net, const int family,
257 const unsigned short port, int flags,
258 const struct cred *cred)
259{
260 struct svc_xprt_class *xcl;
261
262 spin_lock(&svc_xprt_class_lock);
263 list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
264 struct svc_xprt *newxprt;
265 unsigned short newport;
266
267 if (strcmp(xprt_name, xcl->xcl_name))
268 continue;
269
270 if (!try_module_get(xcl->xcl_owner))
271 goto err;
272
273 spin_unlock(&svc_xprt_class_lock);
274 newxprt = __svc_xpo_create(xcl, serv, net, family, port, flags);
275 if (IS_ERR(newxprt)) {
276 module_put(xcl->xcl_owner);
277 return PTR_ERR(newxprt);
278 }
279 newxprt->xpt_cred = get_cred(cred);
280 svc_add_new_perm_xprt(serv, newxprt);
281 newport = svc_xprt_local_port(newxprt);
282 return newport;
283 }
284 err:
285 spin_unlock(&svc_xprt_class_lock);
286 /* This errno is exposed to user space. Provide a reasonable
287 * perror msg for a bad transport. */
288 return -EPROTONOSUPPORT;
289}
290
291int svc_create_xprt(struct svc_serv *serv, const char *xprt_name,
292 struct net *net, const int family,
293 const unsigned short port, int flags,
294 const struct cred *cred)
295{
296 int err;
297
298 dprintk("svc: creating transport %s[%d]\n", xprt_name, port);
299 err = _svc_create_xprt(serv, xprt_name, net, family, port, flags, cred);
300 if (err == -EPROTONOSUPPORT) {
301 request_module("svc%s", xprt_name);
302 err = _svc_create_xprt(serv, xprt_name, net, family, port, flags, cred);
303 }
304 if (err < 0)
305 dprintk("svc: transport %s not found, err %d\n",
306 xprt_name, -err);
307 return err;
308}
309EXPORT_SYMBOL_GPL(svc_create_xprt);
310
311/*
312 * Copy the local and remote xprt addresses to the rqstp structure
313 */
314void svc_xprt_copy_addrs(struct svc_rqst *rqstp, struct svc_xprt *xprt)
315{
316 memcpy(&rqstp->rq_addr, &xprt->xpt_remote, xprt->xpt_remotelen);
317 rqstp->rq_addrlen = xprt->xpt_remotelen;
318
319 /*
320 * Destination address in request is needed for binding the
321 * source address in RPC replies/callbacks later.
322 */
323 memcpy(&rqstp->rq_daddr, &xprt->xpt_local, xprt->xpt_locallen);
324 rqstp->rq_daddrlen = xprt->xpt_locallen;
325}
326EXPORT_SYMBOL_GPL(svc_xprt_copy_addrs);
327
328/**
329 * svc_print_addr - Format rq_addr field for printing
330 * @rqstp: svc_rqst struct containing address to print
331 * @buf: target buffer for formatted address
332 * @len: length of target buffer
333 *
334 */
335char *svc_print_addr(struct svc_rqst *rqstp, char *buf, size_t len)
336{
337 return __svc_print_addr(svc_addr(rqstp), buf, len);
338}
339EXPORT_SYMBOL_GPL(svc_print_addr);
340
341static bool svc_xprt_slots_in_range(struct svc_xprt *xprt)
342{
343 unsigned int limit = svc_rpc_per_connection_limit;
344 int nrqsts = atomic_read(&xprt->xpt_nr_rqsts);
345
346 return limit == 0 || (nrqsts >= 0 && nrqsts < limit);
347}
348
349static bool svc_xprt_reserve_slot(struct svc_rqst *rqstp, struct svc_xprt *xprt)
350{
351 if (!test_bit(RQ_DATA, &rqstp->rq_flags)) {
352 if (!svc_xprt_slots_in_range(xprt))
353 return false;
354 atomic_inc(&xprt->xpt_nr_rqsts);
355 set_bit(RQ_DATA, &rqstp->rq_flags);
356 }
357 return true;
358}
359
360static void svc_xprt_release_slot(struct svc_rqst *rqstp)
361{
362 struct svc_xprt *xprt = rqstp->rq_xprt;
363 if (test_and_clear_bit(RQ_DATA, &rqstp->rq_flags)) {
364 atomic_dec(&xprt->xpt_nr_rqsts);
365 smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */
366 svc_xprt_enqueue(xprt);
367 }
368}
369
370static bool svc_xprt_ready(struct svc_xprt *xprt)
371{
372 unsigned long xpt_flags;
373
374 /*
375 * If another cpu has recently updated xpt_flags,
376 * sk_sock->flags, xpt_reserved, or xpt_nr_rqsts, we need to
377 * know about it; otherwise it's possible that both that cpu and
378 * this one could call svc_xprt_enqueue() without either
379 * svc_xprt_enqueue() recognizing that the conditions below
380 * are satisfied, and we could stall indefinitely:
381 */
382 smp_rmb();
383 xpt_flags = READ_ONCE(xprt->xpt_flags);
384
385 if (xpt_flags & (BIT(XPT_CONN) | BIT(XPT_CLOSE)))
386 return true;
387 if (xpt_flags & (BIT(XPT_DATA) | BIT(XPT_DEFERRED))) {
388 if (xprt->xpt_ops->xpo_has_wspace(xprt) &&
389 svc_xprt_slots_in_range(xprt))
390 return true;
391 trace_svc_xprt_no_write_space(xprt);
392 return false;
393 }
394 return false;
395}
396
397void svc_xprt_do_enqueue(struct svc_xprt *xprt)
398{
399 struct svc_pool *pool;
400 struct svc_rqst *rqstp = NULL;
401 int cpu;
402
403 if (!svc_xprt_ready(xprt))
404 return;
405
406 /* Mark transport as busy. It will remain in this state until
407 * the provider calls svc_xprt_received. We update XPT_BUSY
408 * atomically because it also guards against trying to enqueue
409 * the transport twice.
410 */
411 if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
412 return;
413
414 cpu = get_cpu();
415 pool = svc_pool_for_cpu(xprt->xpt_server, cpu);
416
417 atomic_long_inc(&pool->sp_stats.packets);
418
419 spin_lock_bh(&pool->sp_lock);
420 list_add_tail(&xprt->xpt_ready, &pool->sp_sockets);
421 pool->sp_stats.sockets_queued++;
422 spin_unlock_bh(&pool->sp_lock);
423
424 /* find a thread for this xprt */
425 rcu_read_lock();
426 list_for_each_entry_rcu(rqstp, &pool->sp_all_threads, rq_all) {
427 if (test_and_set_bit(RQ_BUSY, &rqstp->rq_flags))
428 continue;
429 atomic_long_inc(&pool->sp_stats.threads_woken);
430 rqstp->rq_qtime = ktime_get();
431 wake_up_process(rqstp->rq_task);
432 goto out_unlock;
433 }
434 set_bit(SP_CONGESTED, &pool->sp_flags);
435 rqstp = NULL;
436out_unlock:
437 rcu_read_unlock();
438 put_cpu();
439 trace_svc_xprt_do_enqueue(xprt, rqstp);
440}
441EXPORT_SYMBOL_GPL(svc_xprt_do_enqueue);
442
443/*
444 * Queue up a transport with data pending. If there are idle nfsd
445 * processes, wake 'em up.
446 *
447 */
448void svc_xprt_enqueue(struct svc_xprt *xprt)
449{
450 if (test_bit(XPT_BUSY, &xprt->xpt_flags))
451 return;
452 xprt->xpt_server->sv_ops->svo_enqueue_xprt(xprt);
453}
454EXPORT_SYMBOL_GPL(svc_xprt_enqueue);
455
456/*
457 * Dequeue the first transport, if there is one.
458 */
459static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool)
460{
461 struct svc_xprt *xprt = NULL;
462
463 if (list_empty(&pool->sp_sockets))
464 goto out;
465
466 spin_lock_bh(&pool->sp_lock);
467 if (likely(!list_empty(&pool->sp_sockets))) {
468 xprt = list_first_entry(&pool->sp_sockets,
469 struct svc_xprt, xpt_ready);
470 list_del_init(&xprt->xpt_ready);
471 svc_xprt_get(xprt);
472 }
473 spin_unlock_bh(&pool->sp_lock);
474out:
475 return xprt;
476}
477
478/**
479 * svc_reserve - change the space reserved for the reply to a request.
480 * @rqstp: The request in question
481 * @space: new max space to reserve
482 *
483 * Each request reserves some space on the output queue of the transport
484 * to make sure the reply fits. This function reduces that reserved
485 * space to be the amount of space used already, plus @space.
486 *
487 */
488void svc_reserve(struct svc_rqst *rqstp, int space)
489{
490 struct svc_xprt *xprt = rqstp->rq_xprt;
491
492 space += rqstp->rq_res.head[0].iov_len;
493
494 if (xprt && space < rqstp->rq_reserved) {
495 atomic_sub((rqstp->rq_reserved - space), &xprt->xpt_reserved);
496 rqstp->rq_reserved = space;
497 smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */
498 svc_xprt_enqueue(xprt);
499 }
500}
501EXPORT_SYMBOL_GPL(svc_reserve);
502
503static void svc_xprt_release(struct svc_rqst *rqstp)
504{
505 struct svc_xprt *xprt = rqstp->rq_xprt;
506
507 xprt->xpt_ops->xpo_release_rqst(rqstp);
508
509 kfree(rqstp->rq_deferred);
510 rqstp->rq_deferred = NULL;
511
512 svc_free_res_pages(rqstp);
513 rqstp->rq_res.page_len = 0;
514 rqstp->rq_res.page_base = 0;
515
516 /* Reset response buffer and release
517 * the reservation.
518 * But first, check that enough space was reserved
519 * for the reply, otherwise we have a bug!
520 */
521 if ((rqstp->rq_res.len) > rqstp->rq_reserved)
522 printk(KERN_ERR "RPC request reserved %d but used %d\n",
523 rqstp->rq_reserved,
524 rqstp->rq_res.len);
525
526 rqstp->rq_res.head[0].iov_len = 0;
527 svc_reserve(rqstp, 0);
528 svc_xprt_release_slot(rqstp);
529 rqstp->rq_xprt = NULL;
530 svc_xprt_put(xprt);
531}
532
533/*
534 * Some svc_serv's will have occasional work to do, even when a xprt is not
535 * waiting to be serviced. This function is there to "kick" a task in one of
536 * those services so that it can wake up and do that work. Note that we only
537 * bother with pool 0 as we don't need to wake up more than one thread for
538 * this purpose.
539 */
540void svc_wake_up(struct svc_serv *serv)
541{
542 struct svc_rqst *rqstp;
543 struct svc_pool *pool;
544
545 pool = &serv->sv_pools[0];
546
547 rcu_read_lock();
548 list_for_each_entry_rcu(rqstp, &pool->sp_all_threads, rq_all) {
549 /* skip any that aren't queued */
550 if (test_bit(RQ_BUSY, &rqstp->rq_flags))
551 continue;
552 rcu_read_unlock();
553 wake_up_process(rqstp->rq_task);
554 trace_svc_wake_up(rqstp->rq_task->pid);
555 return;
556 }
557 rcu_read_unlock();
558
559 /* No free entries available */
560 set_bit(SP_TASK_PENDING, &pool->sp_flags);
561 smp_wmb();
562 trace_svc_wake_up(0);
563}
564EXPORT_SYMBOL_GPL(svc_wake_up);
565
566int svc_port_is_privileged(struct sockaddr *sin)
567{
568 switch (sin->sa_family) {
569 case AF_INET:
570 return ntohs(((struct sockaddr_in *)sin)->sin_port)
571 < PROT_SOCK;
572 case AF_INET6:
573 return ntohs(((struct sockaddr_in6 *)sin)->sin6_port)
574 < PROT_SOCK;
575 default:
576 return 0;
577 }
578}
579
580/*
581 * Make sure that we don't have too many active connections. If we have,
582 * something must be dropped. It's not clear what will happen if we allow
583 * "too many" connections, but when dealing with network-facing software,
584 * we have to code defensively. Here we do that by imposing hard limits.
585 *
586 * There's no point in trying to do random drop here for DoS
587 * prevention. The NFS clients does 1 reconnect in 15 seconds. An
588 * attacker can easily beat that.
589 *
590 * The only somewhat efficient mechanism would be if drop old
591 * connections from the same IP first. But right now we don't even
592 * record the client IP in svc_sock.
593 *
594 * single-threaded services that expect a lot of clients will probably
595 * need to set sv_maxconn to override the default value which is based
596 * on the number of threads
597 */
598static void svc_check_conn_limits(struct svc_serv *serv)
599{
600 unsigned int limit = serv->sv_maxconn ? serv->sv_maxconn :
601 (serv->sv_nrthreads+3) * 20;
602
603 if (serv->sv_tmpcnt > limit) {
604 struct svc_xprt *xprt = NULL;
605 spin_lock_bh(&serv->sv_lock);
606 if (!list_empty(&serv->sv_tempsocks)) {
607 /* Try to help the admin */
608 net_notice_ratelimited("%s: too many open connections, consider increasing the %s\n",
609 serv->sv_name, serv->sv_maxconn ?
610 "max number of connections" :
611 "number of threads");
612 /*
613 * Always select the oldest connection. It's not fair,
614 * but so is life
615 */
616 xprt = list_entry(serv->sv_tempsocks.prev,
617 struct svc_xprt,
618 xpt_list);
619 set_bit(XPT_CLOSE, &xprt->xpt_flags);
620 svc_xprt_get(xprt);
621 }
622 spin_unlock_bh(&serv->sv_lock);
623
624 if (xprt) {
625 svc_xprt_enqueue(xprt);
626 svc_xprt_put(xprt);
627 }
628 }
629}
630
631static int svc_alloc_arg(struct svc_rqst *rqstp)
632{
633 struct svc_serv *serv = rqstp->rq_server;
634 struct xdr_buf *arg;
635 int pages;
636 int i;
637
638 /* now allocate needed pages. If we get a failure, sleep briefly */
639 pages = (serv->sv_max_mesg + 2 * PAGE_SIZE) >> PAGE_SHIFT;
640 if (pages > RPCSVC_MAXPAGES) {
641 pr_warn_once("svc: warning: pages=%u > RPCSVC_MAXPAGES=%lu\n",
642 pages, RPCSVC_MAXPAGES);
643 /* use as many pages as possible */
644 pages = RPCSVC_MAXPAGES;
645 }
646 for (i = 0; i < pages ; i++)
647 while (rqstp->rq_pages[i] == NULL) {
648 struct page *p = alloc_page(GFP_KERNEL);
649 if (!p) {
650 set_current_state(TASK_INTERRUPTIBLE);
651 if (signalled() || kthread_should_stop()) {
652 set_current_state(TASK_RUNNING);
653 return -EINTR;
654 }
655 schedule_timeout(msecs_to_jiffies(500));
656 }
657 rqstp->rq_pages[i] = p;
658 }
659 rqstp->rq_page_end = &rqstp->rq_pages[i];
660 rqstp->rq_pages[i++] = NULL; /* this might be seen in nfs_read_actor */
661
662 /* Make arg->head point to first page and arg->pages point to rest */
663 arg = &rqstp->rq_arg;
664 arg->head[0].iov_base = page_address(rqstp->rq_pages[0]);
665 arg->head[0].iov_len = PAGE_SIZE;
666 arg->pages = rqstp->rq_pages + 1;
667 arg->page_base = 0;
668 /* save at least one page for response */
669 arg->page_len = (pages-2)*PAGE_SIZE;
670 arg->len = (pages-1)*PAGE_SIZE;
671 arg->tail[0].iov_len = 0;
672 return 0;
673}
674
675static bool
676rqst_should_sleep(struct svc_rqst *rqstp)
677{
678 struct svc_pool *pool = rqstp->rq_pool;
679
680 /* did someone call svc_wake_up? */
681 if (test_and_clear_bit(SP_TASK_PENDING, &pool->sp_flags))
682 return false;
683
684 /* was a socket queued? */
685 if (!list_empty(&pool->sp_sockets))
686 return false;
687
688 /* are we shutting down? */
689 if (signalled() || kthread_should_stop())
690 return false;
691
692 /* are we freezing? */
693 if (freezing(current))
694 return false;
695
696 return true;
697}
698
699static struct svc_xprt *svc_get_next_xprt(struct svc_rqst *rqstp, long timeout)
700{
701 struct svc_pool *pool = rqstp->rq_pool;
702 long time_left = 0;
703
704 /* rq_xprt should be clear on entry */
705 WARN_ON_ONCE(rqstp->rq_xprt);
706
707 rqstp->rq_xprt = svc_xprt_dequeue(pool);
708 if (rqstp->rq_xprt)
709 goto out_found;
710
711 /*
712 * We have to be able to interrupt this wait
713 * to bring down the daemons ...
714 */
715 set_current_state(TASK_INTERRUPTIBLE);
716 smp_mb__before_atomic();
717 clear_bit(SP_CONGESTED, &pool->sp_flags);
718 clear_bit(RQ_BUSY, &rqstp->rq_flags);
719 smp_mb__after_atomic();
720
721 if (likely(rqst_should_sleep(rqstp)))
722 time_left = schedule_timeout(timeout);
723 else
724 __set_current_state(TASK_RUNNING);
725
726 try_to_freeze();
727
728 set_bit(RQ_BUSY, &rqstp->rq_flags);
729 smp_mb__after_atomic();
730 rqstp->rq_xprt = svc_xprt_dequeue(pool);
731 if (rqstp->rq_xprt)
732 goto out_found;
733
734 if (!time_left)
735 atomic_long_inc(&pool->sp_stats.threads_timedout);
736
737 if (signalled() || kthread_should_stop())
738 return ERR_PTR(-EINTR);
739 return ERR_PTR(-EAGAIN);
740out_found:
741 /* Normally we will wait up to 5 seconds for any required
742 * cache information to be provided.
743 */
744 if (!test_bit(SP_CONGESTED, &pool->sp_flags))
745 rqstp->rq_chandle.thread_wait = 5*HZ;
746 else
747 rqstp->rq_chandle.thread_wait = 1*HZ;
748 trace_svc_xprt_dequeue(rqstp);
749 return rqstp->rq_xprt;
750}
751
752static void svc_add_new_temp_xprt(struct svc_serv *serv, struct svc_xprt *newxpt)
753{
754 spin_lock_bh(&serv->sv_lock);
755 set_bit(XPT_TEMP, &newxpt->xpt_flags);
756 list_add(&newxpt->xpt_list, &serv->sv_tempsocks);
757 serv->sv_tmpcnt++;
758 if (serv->sv_temptimer.function == NULL) {
759 /* setup timer to age temp transports */
760 serv->sv_temptimer.function = svc_age_temp_xprts;
761 mod_timer(&serv->sv_temptimer,
762 jiffies + svc_conn_age_period * HZ);
763 }
764 spin_unlock_bh(&serv->sv_lock);
765 svc_xprt_received(newxpt);
766}
767
768static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
769{
770 struct svc_serv *serv = rqstp->rq_server;
771 int len = 0;
772
773 if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) {
774 dprintk("svc_recv: found XPT_CLOSE\n");
775 if (test_and_clear_bit(XPT_KILL_TEMP, &xprt->xpt_flags))
776 xprt->xpt_ops->xpo_kill_temp_xprt(xprt);
777 svc_delete_xprt(xprt);
778 /* Leave XPT_BUSY set on the dead xprt: */
779 goto out;
780 }
781 if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) {
782 struct svc_xprt *newxpt;
783 /*
784 * We know this module_get will succeed because the
785 * listener holds a reference too
786 */
787 __module_get(xprt->xpt_class->xcl_owner);
788 svc_check_conn_limits(xprt->xpt_server);
789 newxpt = xprt->xpt_ops->xpo_accept(xprt);
790 if (newxpt) {
791 newxpt->xpt_cred = get_cred(xprt->xpt_cred);
792 svc_add_new_temp_xprt(serv, newxpt);
793 } else
794 module_put(xprt->xpt_class->xcl_owner);
795 } else if (svc_xprt_reserve_slot(rqstp, xprt)) {
796 /* XPT_DATA|XPT_DEFERRED case: */
797 dprintk("svc: server %p, pool %u, transport %p, inuse=%d\n",
798 rqstp, rqstp->rq_pool->sp_id, xprt,
799 kref_read(&xprt->xpt_ref));
800 rqstp->rq_deferred = svc_deferred_dequeue(xprt);
801 if (rqstp->rq_deferred)
802 len = svc_deferred_recv(rqstp);
803 else
804 len = xprt->xpt_ops->xpo_recvfrom(rqstp);
805 rqstp->rq_stime = ktime_get();
806 rqstp->rq_reserved = serv->sv_max_mesg;
807 atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
808 }
809 /* clear XPT_BUSY: */
810 svc_xprt_received(xprt);
811out:
812 trace_svc_handle_xprt(xprt, len);
813 return len;
814}
815
816/*
817 * Receive the next request on any transport. This code is carefully
818 * organised not to touch any cachelines in the shared svc_serv
819 * structure, only cachelines in the local svc_pool.
820 */
821int svc_recv(struct svc_rqst *rqstp, long timeout)
822{
823 struct svc_xprt *xprt = NULL;
824 struct svc_serv *serv = rqstp->rq_server;
825 int len, err;
826
827 dprintk("svc: server %p waiting for data (to = %ld)\n",
828 rqstp, timeout);
829
830 if (rqstp->rq_xprt)
831 printk(KERN_ERR
832 "svc_recv: service %p, transport not NULL!\n",
833 rqstp);
834
835 err = svc_alloc_arg(rqstp);
836 if (err)
837 goto out;
838
839 try_to_freeze();
840 cond_resched();
841 err = -EINTR;
842 if (signalled() || kthread_should_stop())
843 goto out;
844
845 xprt = svc_get_next_xprt(rqstp, timeout);
846 if (IS_ERR(xprt)) {
847 err = PTR_ERR(xprt);
848 goto out;
849 }
850
851 len = svc_handle_xprt(rqstp, xprt);
852
853 /* No data, incomplete (TCP) read, or accept() */
854 err = -EAGAIN;
855 if (len <= 0)
856 goto out_release;
857
858 clear_bit(XPT_OLD, &xprt->xpt_flags);
859
860 xprt->xpt_ops->xpo_secure_port(rqstp);
861 rqstp->rq_chandle.defer = svc_defer;
862 rqstp->rq_xid = svc_getu32(&rqstp->rq_arg.head[0]);
863
864 if (serv->sv_stats)
865 serv->sv_stats->netcnt++;
866 trace_svc_recv(rqstp, len);
867 return len;
868out_release:
869 rqstp->rq_res.len = 0;
870 svc_xprt_release(rqstp);
871out:
872 return err;
873}
874EXPORT_SYMBOL_GPL(svc_recv);
875
876/*
877 * Drop request
878 */
879void svc_drop(struct svc_rqst *rqstp)
880{
881 trace_svc_drop(rqstp);
882 dprintk("svc: xprt %p dropped request\n", rqstp->rq_xprt);
883 svc_xprt_release(rqstp);
884}
885EXPORT_SYMBOL_GPL(svc_drop);
886
887/*
888 * Return reply to client.
889 */
890int svc_send(struct svc_rqst *rqstp)
891{
892 struct svc_xprt *xprt;
893 int len = -EFAULT;
894 struct xdr_buf *xb;
895
896 xprt = rqstp->rq_xprt;
897 if (!xprt)
898 goto out;
899
900 /* release the receive skb before sending the reply */
901 xprt->xpt_ops->xpo_release_rqst(rqstp);
902
903 /* calculate over-all length */
904 xb = &rqstp->rq_res;
905 xb->len = xb->head[0].iov_len +
906 xb->page_len +
907 xb->tail[0].iov_len;
908
909 /* Grab mutex to serialize outgoing data. */
910 mutex_lock(&xprt->xpt_mutex);
911 trace_svc_stats_latency(rqstp);
912 if (test_bit(XPT_DEAD, &xprt->xpt_flags)
913 || test_bit(XPT_CLOSE, &xprt->xpt_flags))
914 len = -ENOTCONN;
915 else
916 len = xprt->xpt_ops->xpo_sendto(rqstp);
917 mutex_unlock(&xprt->xpt_mutex);
918 trace_svc_send(rqstp, len);
919 svc_xprt_release(rqstp);
920
921 if (len == -ECONNREFUSED || len == -ENOTCONN || len == -EAGAIN)
922 len = 0;
923out:
924 return len;
925}
926
927/*
928 * Timer function to close old temporary transports, using
929 * a mark-and-sweep algorithm.
930 */
931static void svc_age_temp_xprts(struct timer_list *t)
932{
933 struct svc_serv *serv = from_timer(serv, t, sv_temptimer);
934 struct svc_xprt *xprt;
935 struct list_head *le, *next;
936
937 dprintk("svc_age_temp_xprts\n");
938
939 if (!spin_trylock_bh(&serv->sv_lock)) {
940 /* busy, try again 1 sec later */
941 dprintk("svc_age_temp_xprts: busy\n");
942 mod_timer(&serv->sv_temptimer, jiffies + HZ);
943 return;
944 }
945
946 list_for_each_safe(le, next, &serv->sv_tempsocks) {
947 xprt = list_entry(le, struct svc_xprt, xpt_list);
948
949 /* First time through, just mark it OLD. Second time
950 * through, close it. */
951 if (!test_and_set_bit(XPT_OLD, &xprt->xpt_flags))
952 continue;
953 if (kref_read(&xprt->xpt_ref) > 1 ||
954 test_bit(XPT_BUSY, &xprt->xpt_flags))
955 continue;
956 list_del_init(le);
957 set_bit(XPT_CLOSE, &xprt->xpt_flags);
958 dprintk("queuing xprt %p for closing\n", xprt);
959
960 /* a thread will dequeue and close it soon */
961 svc_xprt_enqueue(xprt);
962 }
963 spin_unlock_bh(&serv->sv_lock);
964
965 mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ);
966}
967
968/* Close temporary transports whose xpt_local matches server_addr immediately
969 * instead of waiting for them to be picked up by the timer.
970 *
971 * This is meant to be called from a notifier_block that runs when an ip
972 * address is deleted.
973 */
974void svc_age_temp_xprts_now(struct svc_serv *serv, struct sockaddr *server_addr)
975{
976 struct svc_xprt *xprt;
977 struct list_head *le, *next;
978 LIST_HEAD(to_be_closed);
979
980 spin_lock_bh(&serv->sv_lock);
981 list_for_each_safe(le, next, &serv->sv_tempsocks) {
982 xprt = list_entry(le, struct svc_xprt, xpt_list);
983 if (rpc_cmp_addr(server_addr, (struct sockaddr *)
984 &xprt->xpt_local)) {
985 dprintk("svc_age_temp_xprts_now: found %p\n", xprt);
986 list_move(le, &to_be_closed);
987 }
988 }
989 spin_unlock_bh(&serv->sv_lock);
990
991 while (!list_empty(&to_be_closed)) {
992 le = to_be_closed.next;
993 list_del_init(le);
994 xprt = list_entry(le, struct svc_xprt, xpt_list);
995 set_bit(XPT_CLOSE, &xprt->xpt_flags);
996 set_bit(XPT_KILL_TEMP, &xprt->xpt_flags);
997 dprintk("svc_age_temp_xprts_now: queuing xprt %p for closing\n",
998 xprt);
999 svc_xprt_enqueue(xprt);
1000 }
1001}
1002EXPORT_SYMBOL_GPL(svc_age_temp_xprts_now);
1003
1004static void call_xpt_users(struct svc_xprt *xprt)
1005{
1006 struct svc_xpt_user *u;
1007
1008 spin_lock(&xprt->xpt_lock);
1009 while (!list_empty(&xprt->xpt_users)) {
1010 u = list_first_entry(&xprt->xpt_users, struct svc_xpt_user, list);
1011 list_del_init(&u->list);
1012 u->callback(u);
1013 }
1014 spin_unlock(&xprt->xpt_lock);
1015}
1016
1017/*
1018 * Remove a dead transport
1019 */
1020static void svc_delete_xprt(struct svc_xprt *xprt)
1021{
1022 struct svc_serv *serv = xprt->xpt_server;
1023 struct svc_deferred_req *dr;
1024
1025 /* Only do this once */
1026 if (test_and_set_bit(XPT_DEAD, &xprt->xpt_flags))
1027 BUG();
1028
1029 dprintk("svc: svc_delete_xprt(%p)\n", xprt);
1030 xprt->xpt_ops->xpo_detach(xprt);
1031
1032 spin_lock_bh(&serv->sv_lock);
1033 list_del_init(&xprt->xpt_list);
1034 WARN_ON_ONCE(!list_empty(&xprt->xpt_ready));
1035 if (test_bit(XPT_TEMP, &xprt->xpt_flags))
1036 serv->sv_tmpcnt--;
1037 spin_unlock_bh(&serv->sv_lock);
1038
1039 while ((dr = svc_deferred_dequeue(xprt)) != NULL)
1040 kfree(dr);
1041
1042 call_xpt_users(xprt);
1043 svc_xprt_put(xprt);
1044}
1045
1046void svc_close_xprt(struct svc_xprt *xprt)
1047{
1048 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1049 if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
1050 /* someone else will have to effect the close */
1051 return;
1052 /*
1053 * We expect svc_close_xprt() to work even when no threads are
1054 * running (e.g., while configuring the server before starting
1055 * any threads), so if the transport isn't busy, we delete
1056 * it ourself:
1057 */
1058 svc_delete_xprt(xprt);
1059}
1060EXPORT_SYMBOL_GPL(svc_close_xprt);
1061
1062static int svc_close_list(struct svc_serv *serv, struct list_head *xprt_list, struct net *net)
1063{
1064 struct svc_xprt *xprt;
1065 int ret = 0;
1066
1067 spin_lock(&serv->sv_lock);
1068 list_for_each_entry(xprt, xprt_list, xpt_list) {
1069 if (xprt->xpt_net != net)
1070 continue;
1071 ret++;
1072 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1073 svc_xprt_enqueue(xprt);
1074 }
1075 spin_unlock(&serv->sv_lock);
1076 return ret;
1077}
1078
1079static struct svc_xprt *svc_dequeue_net(struct svc_serv *serv, struct net *net)
1080{
1081 struct svc_pool *pool;
1082 struct svc_xprt *xprt;
1083 struct svc_xprt *tmp;
1084 int i;
1085
1086 for (i = 0; i < serv->sv_nrpools; i++) {
1087 pool = &serv->sv_pools[i];
1088
1089 spin_lock_bh(&pool->sp_lock);
1090 list_for_each_entry_safe(xprt, tmp, &pool->sp_sockets, xpt_ready) {
1091 if (xprt->xpt_net != net)
1092 continue;
1093 list_del_init(&xprt->xpt_ready);
1094 spin_unlock_bh(&pool->sp_lock);
1095 return xprt;
1096 }
1097 spin_unlock_bh(&pool->sp_lock);
1098 }
1099 return NULL;
1100}
1101
1102static void svc_clean_up_xprts(struct svc_serv *serv, struct net *net)
1103{
1104 struct svc_xprt *xprt;
1105
1106 while ((xprt = svc_dequeue_net(serv, net))) {
1107 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1108 svc_delete_xprt(xprt);
1109 }
1110}
1111
1112/*
1113 * Server threads may still be running (especially in the case where the
1114 * service is still running in other network namespaces).
1115 *
1116 * So we shut down sockets the same way we would on a running server, by
1117 * setting XPT_CLOSE, enqueuing, and letting a thread pick it up to do
1118 * the close. In the case there are no such other threads,
1119 * threads running, svc_clean_up_xprts() does a simple version of a
1120 * server's main event loop, and in the case where there are other
1121 * threads, we may need to wait a little while and then check again to
1122 * see if they're done.
1123 */
1124void svc_close_net(struct svc_serv *serv, struct net *net)
1125{
1126 int delay = 0;
1127
1128 while (svc_close_list(serv, &serv->sv_permsocks, net) +
1129 svc_close_list(serv, &serv->sv_tempsocks, net)) {
1130
1131 svc_clean_up_xprts(serv, net);
1132 msleep(delay++);
1133 }
1134}
1135
1136/*
1137 * Handle defer and revisit of requests
1138 */
1139
1140static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
1141{
1142 struct svc_deferred_req *dr =
1143 container_of(dreq, struct svc_deferred_req, handle);
1144 struct svc_xprt *xprt = dr->xprt;
1145
1146 spin_lock(&xprt->xpt_lock);
1147 set_bit(XPT_DEFERRED, &xprt->xpt_flags);
1148 if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) {
1149 spin_unlock(&xprt->xpt_lock);
1150 dprintk("revisit canceled\n");
1151 svc_xprt_put(xprt);
1152 trace_svc_drop_deferred(dr);
1153 kfree(dr);
1154 return;
1155 }
1156 dprintk("revisit queued\n");
1157 dr->xprt = NULL;
1158 list_add(&dr->handle.recent, &xprt->xpt_deferred);
1159 spin_unlock(&xprt->xpt_lock);
1160 svc_xprt_enqueue(xprt);
1161 svc_xprt_put(xprt);
1162}
1163
1164/*
1165 * Save the request off for later processing. The request buffer looks
1166 * like this:
1167 *
1168 * <xprt-header><rpc-header><rpc-pagelist><rpc-tail>
1169 *
1170 * This code can only handle requests that consist of an xprt-header
1171 * and rpc-header.
1172 */
1173static struct cache_deferred_req *svc_defer(struct cache_req *req)
1174{
1175 struct svc_rqst *rqstp = container_of(req, struct svc_rqst, rq_chandle);
1176 struct svc_deferred_req *dr;
1177
1178 if (rqstp->rq_arg.page_len || !test_bit(RQ_USEDEFERRAL, &rqstp->rq_flags))
1179 return NULL; /* if more than a page, give up FIXME */
1180 if (rqstp->rq_deferred) {
1181 dr = rqstp->rq_deferred;
1182 rqstp->rq_deferred = NULL;
1183 } else {
1184 size_t skip;
1185 size_t size;
1186 /* FIXME maybe discard if size too large */
1187 size = sizeof(struct svc_deferred_req) + rqstp->rq_arg.len;
1188 dr = kmalloc(size, GFP_KERNEL);
1189 if (dr == NULL)
1190 return NULL;
1191
1192 dr->handle.owner = rqstp->rq_server;
1193 dr->prot = rqstp->rq_prot;
1194 memcpy(&dr->addr, &rqstp->rq_addr, rqstp->rq_addrlen);
1195 dr->addrlen = rqstp->rq_addrlen;
1196 dr->daddr = rqstp->rq_daddr;
1197 dr->argslen = rqstp->rq_arg.len >> 2;
1198 dr->xprt_hlen = rqstp->rq_xprt_hlen;
1199
1200 /* back up head to the start of the buffer and copy */
1201 skip = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len;
1202 memcpy(dr->args, rqstp->rq_arg.head[0].iov_base - skip,
1203 dr->argslen << 2);
1204 }
1205 svc_xprt_get(rqstp->rq_xprt);
1206 dr->xprt = rqstp->rq_xprt;
1207 set_bit(RQ_DROPME, &rqstp->rq_flags);
1208
1209 dr->handle.revisit = svc_revisit;
1210 trace_svc_defer(rqstp);
1211 return &dr->handle;
1212}
1213
1214/*
1215 * recv data from a deferred request into an active one
1216 */
1217static int svc_deferred_recv(struct svc_rqst *rqstp)
1218{
1219 struct svc_deferred_req *dr = rqstp->rq_deferred;
1220
1221 /* setup iov_base past transport header */
1222 rqstp->rq_arg.head[0].iov_base = dr->args + (dr->xprt_hlen>>2);
1223 /* The iov_len does not include the transport header bytes */
1224 rqstp->rq_arg.head[0].iov_len = (dr->argslen<<2) - dr->xprt_hlen;
1225 rqstp->rq_arg.page_len = 0;
1226 /* The rq_arg.len includes the transport header bytes */
1227 rqstp->rq_arg.len = dr->argslen<<2;
1228 rqstp->rq_prot = dr->prot;
1229 memcpy(&rqstp->rq_addr, &dr->addr, dr->addrlen);
1230 rqstp->rq_addrlen = dr->addrlen;
1231 /* Save off transport header len in case we get deferred again */
1232 rqstp->rq_xprt_hlen = dr->xprt_hlen;
1233 rqstp->rq_daddr = dr->daddr;
1234 rqstp->rq_respages = rqstp->rq_pages;
1235 return (dr->argslen<<2) - dr->xprt_hlen;
1236}
1237
1238
1239static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt)
1240{
1241 struct svc_deferred_req *dr = NULL;
1242
1243 if (!test_bit(XPT_DEFERRED, &xprt->xpt_flags))
1244 return NULL;
1245 spin_lock(&xprt->xpt_lock);
1246 if (!list_empty(&xprt->xpt_deferred)) {
1247 dr = list_entry(xprt->xpt_deferred.next,
1248 struct svc_deferred_req,
1249 handle.recent);
1250 list_del_init(&dr->handle.recent);
1251 trace_svc_revisit_deferred(dr);
1252 } else
1253 clear_bit(XPT_DEFERRED, &xprt->xpt_flags);
1254 spin_unlock(&xprt->xpt_lock);
1255 return dr;
1256}
1257
1258/**
1259 * svc_find_xprt - find an RPC transport instance
1260 * @serv: pointer to svc_serv to search
1261 * @xcl_name: C string containing transport's class name
1262 * @net: owner net pointer
1263 * @af: Address family of transport's local address
1264 * @port: transport's IP port number
1265 *
1266 * Return the transport instance pointer for the endpoint accepting
1267 * connections/peer traffic from the specified transport class,
1268 * address family and port.
1269 *
1270 * Specifying 0 for the address family or port is effectively a
1271 * wild-card, and will result in matching the first transport in the
1272 * service's list that has a matching class name.
1273 */
1274struct svc_xprt *svc_find_xprt(struct svc_serv *serv, const char *xcl_name,
1275 struct net *net, const sa_family_t af,
1276 const unsigned short port)
1277{
1278 struct svc_xprt *xprt;
1279 struct svc_xprt *found = NULL;
1280
1281 /* Sanity check the args */
1282 if (serv == NULL || xcl_name == NULL)
1283 return found;
1284
1285 spin_lock_bh(&serv->sv_lock);
1286 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1287 if (xprt->xpt_net != net)
1288 continue;
1289 if (strcmp(xprt->xpt_class->xcl_name, xcl_name))
1290 continue;
1291 if (af != AF_UNSPEC && af != xprt->xpt_local.ss_family)
1292 continue;
1293 if (port != 0 && port != svc_xprt_local_port(xprt))
1294 continue;
1295 found = xprt;
1296 svc_xprt_get(xprt);
1297 break;
1298 }
1299 spin_unlock_bh(&serv->sv_lock);
1300 return found;
1301}
1302EXPORT_SYMBOL_GPL(svc_find_xprt);
1303
1304static int svc_one_xprt_name(const struct svc_xprt *xprt,
1305 char *pos, int remaining)
1306{
1307 int len;
1308
1309 len = snprintf(pos, remaining, "%s %u\n",
1310 xprt->xpt_class->xcl_name,
1311 svc_xprt_local_port(xprt));
1312 if (len >= remaining)
1313 return -ENAMETOOLONG;
1314 return len;
1315}
1316
1317/**
1318 * svc_xprt_names - format a buffer with a list of transport names
1319 * @serv: pointer to an RPC service
1320 * @buf: pointer to a buffer to be filled in
1321 * @buflen: length of buffer to be filled in
1322 *
1323 * Fills in @buf with a string containing a list of transport names,
1324 * each name terminated with '\n'.
1325 *
1326 * Returns positive length of the filled-in string on success; otherwise
1327 * a negative errno value is returned if an error occurs.
1328 */
1329int svc_xprt_names(struct svc_serv *serv, char *buf, const int buflen)
1330{
1331 struct svc_xprt *xprt;
1332 int len, totlen;
1333 char *pos;
1334
1335 /* Sanity check args */
1336 if (!serv)
1337 return 0;
1338
1339 spin_lock_bh(&serv->sv_lock);
1340
1341 pos = buf;
1342 totlen = 0;
1343 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1344 len = svc_one_xprt_name(xprt, pos, buflen - totlen);
1345 if (len < 0) {
1346 *buf = '\0';
1347 totlen = len;
1348 }
1349 if (len <= 0)
1350 break;
1351
1352 pos += len;
1353 totlen += len;
1354 }
1355
1356 spin_unlock_bh(&serv->sv_lock);
1357 return totlen;
1358}
1359EXPORT_SYMBOL_GPL(svc_xprt_names);
1360
1361
1362/*----------------------------------------------------------------------------*/
1363
1364static void *svc_pool_stats_start(struct seq_file *m, loff_t *pos)
1365{
1366 unsigned int pidx = (unsigned int)*pos;
1367 struct svc_serv *serv = m->private;
1368
1369 dprintk("svc_pool_stats_start, *pidx=%u\n", pidx);
1370
1371 if (!pidx)
1372 return SEQ_START_TOKEN;
1373 return (pidx > serv->sv_nrpools ? NULL : &serv->sv_pools[pidx-1]);
1374}
1375
1376static void *svc_pool_stats_next(struct seq_file *m, void *p, loff_t *pos)
1377{
1378 struct svc_pool *pool = p;
1379 struct svc_serv *serv = m->private;
1380
1381 dprintk("svc_pool_stats_next, *pos=%llu\n", *pos);
1382
1383 if (p == SEQ_START_TOKEN) {
1384 pool = &serv->sv_pools[0];
1385 } else {
1386 unsigned int pidx = (pool - &serv->sv_pools[0]);
1387 if (pidx < serv->sv_nrpools-1)
1388 pool = &serv->sv_pools[pidx+1];
1389 else
1390 pool = NULL;
1391 }
1392 ++*pos;
1393 return pool;
1394}
1395
1396static void svc_pool_stats_stop(struct seq_file *m, void *p)
1397{
1398}
1399
1400static int svc_pool_stats_show(struct seq_file *m, void *p)
1401{
1402 struct svc_pool *pool = p;
1403
1404 if (p == SEQ_START_TOKEN) {
1405 seq_puts(m, "# pool packets-arrived sockets-enqueued threads-woken threads-timedout\n");
1406 return 0;
1407 }
1408
1409 seq_printf(m, "%u %lu %lu %lu %lu\n",
1410 pool->sp_id,
1411 (unsigned long)atomic_long_read(&pool->sp_stats.packets),
1412 pool->sp_stats.sockets_queued,
1413 (unsigned long)atomic_long_read(&pool->sp_stats.threads_woken),
1414 (unsigned long)atomic_long_read(&pool->sp_stats.threads_timedout));
1415
1416 return 0;
1417}
1418
1419static const struct seq_operations svc_pool_stats_seq_ops = {
1420 .start = svc_pool_stats_start,
1421 .next = svc_pool_stats_next,
1422 .stop = svc_pool_stats_stop,
1423 .show = svc_pool_stats_show,
1424};
1425
1426int svc_pool_stats_open(struct svc_serv *serv, struct file *file)
1427{
1428 int err;
1429
1430 err = seq_open(file, &svc_pool_stats_seq_ops);
1431 if (!err)
1432 ((struct seq_file *) file->private_data)->private = serv;
1433 return err;
1434}
1435EXPORT_SYMBOL(svc_pool_stats_open);
1436
1437/*----------------------------------------------------------------------------*/
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/net/sunrpc/svc_xprt.c
4 *
5 * Author: Tom Tucker <tom@opengridcomputing.com>
6 */
7
8#include <linux/sched.h>
9#include <linux/sched/mm.h>
10#include <linux/errno.h>
11#include <linux/freezer.h>
12#include <linux/slab.h>
13#include <net/sock.h>
14#include <linux/sunrpc/addr.h>
15#include <linux/sunrpc/stats.h>
16#include <linux/sunrpc/svc_xprt.h>
17#include <linux/sunrpc/svcsock.h>
18#include <linux/sunrpc/xprt.h>
19#include <linux/sunrpc/bc_xprt.h>
20#include <linux/module.h>
21#include <linux/netdevice.h>
22#include <trace/events/sunrpc.h>
23
24#define RPCDBG_FACILITY RPCDBG_SVCXPRT
25
26static unsigned int svc_rpc_per_connection_limit __read_mostly;
27module_param(svc_rpc_per_connection_limit, uint, 0644);
28
29
30static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt);
31static int svc_deferred_recv(struct svc_rqst *rqstp);
32static struct cache_deferred_req *svc_defer(struct cache_req *req);
33static void svc_age_temp_xprts(struct timer_list *t);
34static void svc_delete_xprt(struct svc_xprt *xprt);
35
36/* apparently the "standard" is that clients close
37 * idle connections after 5 minutes, servers after
38 * 6 minutes
39 * http://nfsv4bat.org/Documents/ConnectAThon/1996/nfstcp.pdf
40 */
41static int svc_conn_age_period = 6*60;
42
43/* List of registered transport classes */
44static DEFINE_SPINLOCK(svc_xprt_class_lock);
45static LIST_HEAD(svc_xprt_class_list);
46
47/* SMP locking strategy:
48 *
49 * svc_serv->sv_lock protects sv_tempsocks, sv_permsocks, sv_tmpcnt.
50 * when both need to be taken (rare), svc_serv->sv_lock is first.
51 * The "service mutex" protects svc_serv->sv_nrthread.
52 * svc_sock->sk_lock protects the svc_sock->sk_deferred list
53 * and the ->sk_info_authunix cache.
54 *
55 * The XPT_BUSY bit in xprt->xpt_flags prevents a transport being
56 * enqueued multiply. During normal transport processing this bit
57 * is set by svc_xprt_enqueue and cleared by svc_xprt_received.
58 * Providers should not manipulate this bit directly.
59 *
60 * Some flags can be set to certain values at any time
61 * providing that certain rules are followed:
62 *
63 * XPT_CONN, XPT_DATA:
64 * - Can be set or cleared at any time.
65 * - After a set, svc_xprt_enqueue must be called to enqueue
66 * the transport for processing.
67 * - After a clear, the transport must be read/accepted.
68 * If this succeeds, it must be set again.
69 * XPT_CLOSE:
70 * - Can set at any time. It is never cleared.
71 * XPT_DEAD:
72 * - Can only be set while XPT_BUSY is held which ensures
73 * that no other thread will be using the transport or will
74 * try to set XPT_DEAD.
75 */
76
77/**
78 * svc_reg_xprt_class - Register a server-side RPC transport class
79 * @xcl: New transport class to be registered
80 *
81 * Returns zero on success; otherwise a negative errno is returned.
82 */
83int svc_reg_xprt_class(struct svc_xprt_class *xcl)
84{
85 struct svc_xprt_class *cl;
86 int res = -EEXIST;
87
88 INIT_LIST_HEAD(&xcl->xcl_list);
89 spin_lock(&svc_xprt_class_lock);
90 /* Make sure there isn't already a class with the same name */
91 list_for_each_entry(cl, &svc_xprt_class_list, xcl_list) {
92 if (strcmp(xcl->xcl_name, cl->xcl_name) == 0)
93 goto out;
94 }
95 list_add_tail(&xcl->xcl_list, &svc_xprt_class_list);
96 res = 0;
97out:
98 spin_unlock(&svc_xprt_class_lock);
99 return res;
100}
101EXPORT_SYMBOL_GPL(svc_reg_xprt_class);
102
103/**
104 * svc_unreg_xprt_class - Unregister a server-side RPC transport class
105 * @xcl: Transport class to be unregistered
106 *
107 */
108void svc_unreg_xprt_class(struct svc_xprt_class *xcl)
109{
110 spin_lock(&svc_xprt_class_lock);
111 list_del_init(&xcl->xcl_list);
112 spin_unlock(&svc_xprt_class_lock);
113}
114EXPORT_SYMBOL_GPL(svc_unreg_xprt_class);
115
116/**
117 * svc_print_xprts - Format the transport list for printing
118 * @buf: target buffer for formatted address
119 * @maxlen: length of target buffer
120 *
121 * Fills in @buf with a string containing a list of transport names, each name
122 * terminated with '\n'. If the buffer is too small, some entries may be
123 * missing, but it is guaranteed that all lines in the output buffer are
124 * complete.
125 *
126 * Returns positive length of the filled-in string.
127 */
128int svc_print_xprts(char *buf, int maxlen)
129{
130 struct svc_xprt_class *xcl;
131 char tmpstr[80];
132 int len = 0;
133 buf[0] = '\0';
134
135 spin_lock(&svc_xprt_class_lock);
136 list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
137 int slen;
138
139 slen = snprintf(tmpstr, sizeof(tmpstr), "%s %d\n",
140 xcl->xcl_name, xcl->xcl_max_payload);
141 if (slen >= sizeof(tmpstr) || len + slen >= maxlen)
142 break;
143 len += slen;
144 strcat(buf, tmpstr);
145 }
146 spin_unlock(&svc_xprt_class_lock);
147
148 return len;
149}
150
151/**
152 * svc_xprt_deferred_close - Close a transport
153 * @xprt: transport instance
154 *
155 * Used in contexts that need to defer the work of shutting down
156 * the transport to an nfsd thread.
157 */
158void svc_xprt_deferred_close(struct svc_xprt *xprt)
159{
160 trace_svc_xprt_close(xprt);
161 if (!test_and_set_bit(XPT_CLOSE, &xprt->xpt_flags))
162 svc_xprt_enqueue(xprt);
163}
164EXPORT_SYMBOL_GPL(svc_xprt_deferred_close);
165
166static void svc_xprt_free(struct kref *kref)
167{
168 struct svc_xprt *xprt =
169 container_of(kref, struct svc_xprt, xpt_ref);
170 struct module *owner = xprt->xpt_class->xcl_owner;
171 if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags))
172 svcauth_unix_info_release(xprt);
173 put_cred(xprt->xpt_cred);
174 put_net_track(xprt->xpt_net, &xprt->ns_tracker);
175 /* See comment on corresponding get in xs_setup_bc_tcp(): */
176 if (xprt->xpt_bc_xprt)
177 xprt_put(xprt->xpt_bc_xprt);
178 if (xprt->xpt_bc_xps)
179 xprt_switch_put(xprt->xpt_bc_xps);
180 trace_svc_xprt_free(xprt);
181 xprt->xpt_ops->xpo_free(xprt);
182 module_put(owner);
183}
184
185void svc_xprt_put(struct svc_xprt *xprt)
186{
187 kref_put(&xprt->xpt_ref, svc_xprt_free);
188}
189EXPORT_SYMBOL_GPL(svc_xprt_put);
190
191/*
192 * Called by transport drivers to initialize the transport independent
193 * portion of the transport instance.
194 */
195void svc_xprt_init(struct net *net, struct svc_xprt_class *xcl,
196 struct svc_xprt *xprt, struct svc_serv *serv)
197{
198 memset(xprt, 0, sizeof(*xprt));
199 xprt->xpt_class = xcl;
200 xprt->xpt_ops = xcl->xcl_ops;
201 kref_init(&xprt->xpt_ref);
202 xprt->xpt_server = serv;
203 INIT_LIST_HEAD(&xprt->xpt_list);
204 INIT_LIST_HEAD(&xprt->xpt_deferred);
205 INIT_LIST_HEAD(&xprt->xpt_users);
206 mutex_init(&xprt->xpt_mutex);
207 spin_lock_init(&xprt->xpt_lock);
208 set_bit(XPT_BUSY, &xprt->xpt_flags);
209 xprt->xpt_net = get_net_track(net, &xprt->ns_tracker, GFP_ATOMIC);
210 strcpy(xprt->xpt_remotebuf, "uninitialized");
211}
212EXPORT_SYMBOL_GPL(svc_xprt_init);
213
214/**
215 * svc_xprt_received - start next receiver thread
216 * @xprt: controlling transport
217 *
218 * The caller must hold the XPT_BUSY bit and must
219 * not thereafter touch transport data.
220 *
221 * Note: XPT_DATA only gets cleared when a read-attempt finds no (or
222 * insufficient) data.
223 */
224void svc_xprt_received(struct svc_xprt *xprt)
225{
226 if (!test_bit(XPT_BUSY, &xprt->xpt_flags)) {
227 WARN_ONCE(1, "xprt=0x%p already busy!", xprt);
228 return;
229 }
230
231 /* As soon as we clear busy, the xprt could be closed and
232 * 'put', so we need a reference to call svc_xprt_enqueue with:
233 */
234 svc_xprt_get(xprt);
235 smp_mb__before_atomic();
236 clear_bit(XPT_BUSY, &xprt->xpt_flags);
237 svc_xprt_enqueue(xprt);
238 svc_xprt_put(xprt);
239}
240EXPORT_SYMBOL_GPL(svc_xprt_received);
241
242void svc_add_new_perm_xprt(struct svc_serv *serv, struct svc_xprt *new)
243{
244 clear_bit(XPT_TEMP, &new->xpt_flags);
245 spin_lock_bh(&serv->sv_lock);
246 list_add(&new->xpt_list, &serv->sv_permsocks);
247 spin_unlock_bh(&serv->sv_lock);
248 svc_xprt_received(new);
249}
250
251static int _svc_xprt_create(struct svc_serv *serv, const char *xprt_name,
252 struct net *net, struct sockaddr *sap,
253 size_t len, int flags, const struct cred *cred)
254{
255 struct svc_xprt_class *xcl;
256
257 spin_lock(&svc_xprt_class_lock);
258 list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
259 struct svc_xprt *newxprt;
260 unsigned short newport;
261
262 if (strcmp(xprt_name, xcl->xcl_name))
263 continue;
264
265 if (!try_module_get(xcl->xcl_owner))
266 goto err;
267
268 spin_unlock(&svc_xprt_class_lock);
269 newxprt = xcl->xcl_ops->xpo_create(serv, net, sap, len, flags);
270 if (IS_ERR(newxprt)) {
271 trace_svc_xprt_create_err(serv->sv_programs->pg_name,
272 xcl->xcl_name, sap, len,
273 newxprt);
274 module_put(xcl->xcl_owner);
275 return PTR_ERR(newxprt);
276 }
277 newxprt->xpt_cred = get_cred(cred);
278 svc_add_new_perm_xprt(serv, newxprt);
279 newport = svc_xprt_local_port(newxprt);
280 return newport;
281 }
282 err:
283 spin_unlock(&svc_xprt_class_lock);
284 /* This errno is exposed to user space. Provide a reasonable
285 * perror msg for a bad transport. */
286 return -EPROTONOSUPPORT;
287}
288
289/**
290 * svc_xprt_create_from_sa - Add a new listener to @serv from socket address
291 * @serv: target RPC service
292 * @xprt_name: transport class name
293 * @net: network namespace
294 * @sap: socket address pointer
295 * @flags: SVC_SOCK flags
296 * @cred: credential to bind to this transport
297 *
298 * Return local xprt port on success or %-EPROTONOSUPPORT on failure
299 */
300int svc_xprt_create_from_sa(struct svc_serv *serv, const char *xprt_name,
301 struct net *net, struct sockaddr *sap,
302 int flags, const struct cred *cred)
303{
304 size_t len;
305 int err;
306
307 switch (sap->sa_family) {
308 case AF_INET:
309 len = sizeof(struct sockaddr_in);
310 break;
311#if IS_ENABLED(CONFIG_IPV6)
312 case AF_INET6:
313 len = sizeof(struct sockaddr_in6);
314 break;
315#endif
316 default:
317 return -EAFNOSUPPORT;
318 }
319
320 err = _svc_xprt_create(serv, xprt_name, net, sap, len, flags, cred);
321 if (err == -EPROTONOSUPPORT) {
322 request_module("svc%s", xprt_name);
323 err = _svc_xprt_create(serv, xprt_name, net, sap, len, flags,
324 cred);
325 }
326
327 return err;
328}
329EXPORT_SYMBOL_GPL(svc_xprt_create_from_sa);
330
331/**
332 * svc_xprt_create - Add a new listener to @serv
333 * @serv: target RPC service
334 * @xprt_name: transport class name
335 * @net: network namespace
336 * @family: network address family
337 * @port: listener port
338 * @flags: SVC_SOCK flags
339 * @cred: credential to bind to this transport
340 *
341 * Return local xprt port on success or %-EPROTONOSUPPORT on failure
342 */
343int svc_xprt_create(struct svc_serv *serv, const char *xprt_name,
344 struct net *net, const int family,
345 const unsigned short port, int flags,
346 const struct cred *cred)
347{
348 struct sockaddr_in sin = {
349 .sin_family = AF_INET,
350 .sin_addr.s_addr = htonl(INADDR_ANY),
351 .sin_port = htons(port),
352 };
353#if IS_ENABLED(CONFIG_IPV6)
354 struct sockaddr_in6 sin6 = {
355 .sin6_family = AF_INET6,
356 .sin6_addr = IN6ADDR_ANY_INIT,
357 .sin6_port = htons(port),
358 };
359#endif
360 struct sockaddr *sap;
361
362 switch (family) {
363 case PF_INET:
364 sap = (struct sockaddr *)&sin;
365 break;
366#if IS_ENABLED(CONFIG_IPV6)
367 case PF_INET6:
368 sap = (struct sockaddr *)&sin6;
369 break;
370#endif
371 default:
372 return -EAFNOSUPPORT;
373 }
374
375 return svc_xprt_create_from_sa(serv, xprt_name, net, sap, flags, cred);
376}
377EXPORT_SYMBOL_GPL(svc_xprt_create);
378
379/*
380 * Copy the local and remote xprt addresses to the rqstp structure
381 */
382void svc_xprt_copy_addrs(struct svc_rqst *rqstp, struct svc_xprt *xprt)
383{
384 memcpy(&rqstp->rq_addr, &xprt->xpt_remote, xprt->xpt_remotelen);
385 rqstp->rq_addrlen = xprt->xpt_remotelen;
386
387 /*
388 * Destination address in request is needed for binding the
389 * source address in RPC replies/callbacks later.
390 */
391 memcpy(&rqstp->rq_daddr, &xprt->xpt_local, xprt->xpt_locallen);
392 rqstp->rq_daddrlen = xprt->xpt_locallen;
393}
394EXPORT_SYMBOL_GPL(svc_xprt_copy_addrs);
395
396/**
397 * svc_print_addr - Format rq_addr field for printing
398 * @rqstp: svc_rqst struct containing address to print
399 * @buf: target buffer for formatted address
400 * @len: length of target buffer
401 *
402 */
403char *svc_print_addr(struct svc_rqst *rqstp, char *buf, size_t len)
404{
405 return __svc_print_addr(svc_addr(rqstp), buf, len);
406}
407EXPORT_SYMBOL_GPL(svc_print_addr);
408
409static bool svc_xprt_slots_in_range(struct svc_xprt *xprt)
410{
411 unsigned int limit = svc_rpc_per_connection_limit;
412 int nrqsts = atomic_read(&xprt->xpt_nr_rqsts);
413
414 return limit == 0 || (nrqsts >= 0 && nrqsts < limit);
415}
416
417static bool svc_xprt_reserve_slot(struct svc_rqst *rqstp, struct svc_xprt *xprt)
418{
419 if (!test_bit(RQ_DATA, &rqstp->rq_flags)) {
420 if (!svc_xprt_slots_in_range(xprt))
421 return false;
422 atomic_inc(&xprt->xpt_nr_rqsts);
423 set_bit(RQ_DATA, &rqstp->rq_flags);
424 }
425 return true;
426}
427
428static void svc_xprt_release_slot(struct svc_rqst *rqstp)
429{
430 struct svc_xprt *xprt = rqstp->rq_xprt;
431 if (test_and_clear_bit(RQ_DATA, &rqstp->rq_flags)) {
432 atomic_dec(&xprt->xpt_nr_rqsts);
433 smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */
434 svc_xprt_enqueue(xprt);
435 }
436}
437
438static bool svc_xprt_ready(struct svc_xprt *xprt)
439{
440 unsigned long xpt_flags;
441
442 /*
443 * If another cpu has recently updated xpt_flags,
444 * sk_sock->flags, xpt_reserved, or xpt_nr_rqsts, we need to
445 * know about it; otherwise it's possible that both that cpu and
446 * this one could call svc_xprt_enqueue() without either
447 * svc_xprt_enqueue() recognizing that the conditions below
448 * are satisfied, and we could stall indefinitely:
449 */
450 smp_rmb();
451 xpt_flags = READ_ONCE(xprt->xpt_flags);
452
453 trace_svc_xprt_enqueue(xprt, xpt_flags);
454 if (xpt_flags & BIT(XPT_BUSY))
455 return false;
456 if (xpt_flags & (BIT(XPT_CONN) | BIT(XPT_CLOSE) | BIT(XPT_HANDSHAKE)))
457 return true;
458 if (xpt_flags & (BIT(XPT_DATA) | BIT(XPT_DEFERRED))) {
459 if (xprt->xpt_ops->xpo_has_wspace(xprt) &&
460 svc_xprt_slots_in_range(xprt))
461 return true;
462 trace_svc_xprt_no_write_space(xprt);
463 return false;
464 }
465 return false;
466}
467
468/**
469 * svc_xprt_enqueue - Queue a transport on an idle nfsd thread
470 * @xprt: transport with data pending
471 *
472 */
473void svc_xprt_enqueue(struct svc_xprt *xprt)
474{
475 struct svc_pool *pool;
476
477 if (!svc_xprt_ready(xprt))
478 return;
479
480 /* Mark transport as busy. It will remain in this state until
481 * the provider calls svc_xprt_received. We update XPT_BUSY
482 * atomically because it also guards against trying to enqueue
483 * the transport twice.
484 */
485 if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
486 return;
487
488 pool = svc_pool_for_cpu(xprt->xpt_server);
489
490 percpu_counter_inc(&pool->sp_sockets_queued);
491 lwq_enqueue(&xprt->xpt_ready, &pool->sp_xprts);
492
493 svc_pool_wake_idle_thread(pool);
494}
495EXPORT_SYMBOL_GPL(svc_xprt_enqueue);
496
497/*
498 * Dequeue the first transport, if there is one.
499 */
500static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool)
501{
502 struct svc_xprt *xprt = NULL;
503
504 xprt = lwq_dequeue(&pool->sp_xprts, struct svc_xprt, xpt_ready);
505 if (xprt)
506 svc_xprt_get(xprt);
507 return xprt;
508}
509
510/**
511 * svc_reserve - change the space reserved for the reply to a request.
512 * @rqstp: The request in question
513 * @space: new max space to reserve
514 *
515 * Each request reserves some space on the output queue of the transport
516 * to make sure the reply fits. This function reduces that reserved
517 * space to be the amount of space used already, plus @space.
518 *
519 */
520void svc_reserve(struct svc_rqst *rqstp, int space)
521{
522 struct svc_xprt *xprt = rqstp->rq_xprt;
523
524 space += rqstp->rq_res.head[0].iov_len;
525
526 if (xprt && space < rqstp->rq_reserved) {
527 atomic_sub((rqstp->rq_reserved - space), &xprt->xpt_reserved);
528 rqstp->rq_reserved = space;
529 smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */
530 svc_xprt_enqueue(xprt);
531 }
532}
533EXPORT_SYMBOL_GPL(svc_reserve);
534
535static void free_deferred(struct svc_xprt *xprt, struct svc_deferred_req *dr)
536{
537 if (!dr)
538 return;
539
540 xprt->xpt_ops->xpo_release_ctxt(xprt, dr->xprt_ctxt);
541 kfree(dr);
542}
543
544static void svc_xprt_release(struct svc_rqst *rqstp)
545{
546 struct svc_xprt *xprt = rqstp->rq_xprt;
547
548 xprt->xpt_ops->xpo_release_ctxt(xprt, rqstp->rq_xprt_ctxt);
549 rqstp->rq_xprt_ctxt = NULL;
550
551 free_deferred(xprt, rqstp->rq_deferred);
552 rqstp->rq_deferred = NULL;
553
554 svc_rqst_release_pages(rqstp);
555 rqstp->rq_res.page_len = 0;
556 rqstp->rq_res.page_base = 0;
557
558 /* Reset response buffer and release
559 * the reservation.
560 * But first, check that enough space was reserved
561 * for the reply, otherwise we have a bug!
562 */
563 if ((rqstp->rq_res.len) > rqstp->rq_reserved)
564 printk(KERN_ERR "RPC request reserved %d but used %d\n",
565 rqstp->rq_reserved,
566 rqstp->rq_res.len);
567
568 rqstp->rq_res.head[0].iov_len = 0;
569 svc_reserve(rqstp, 0);
570 svc_xprt_release_slot(rqstp);
571 rqstp->rq_xprt = NULL;
572 svc_xprt_put(xprt);
573}
574
575/**
576 * svc_wake_up - Wake up a service thread for non-transport work
577 * @serv: RPC service
578 *
579 * Some svc_serv's will have occasional work to do, even when a xprt is not
580 * waiting to be serviced. This function is there to "kick" a task in one of
581 * those services so that it can wake up and do that work. Note that we only
582 * bother with pool 0 as we don't need to wake up more than one thread for
583 * this purpose.
584 */
585void svc_wake_up(struct svc_serv *serv)
586{
587 struct svc_pool *pool = &serv->sv_pools[0];
588
589 set_bit(SP_TASK_PENDING, &pool->sp_flags);
590 svc_pool_wake_idle_thread(pool);
591}
592EXPORT_SYMBOL_GPL(svc_wake_up);
593
594int svc_port_is_privileged(struct sockaddr *sin)
595{
596 switch (sin->sa_family) {
597 case AF_INET:
598 return ntohs(((struct sockaddr_in *)sin)->sin_port)
599 < PROT_SOCK;
600 case AF_INET6:
601 return ntohs(((struct sockaddr_in6 *)sin)->sin6_port)
602 < PROT_SOCK;
603 default:
604 return 0;
605 }
606}
607
608/*
609 * Make sure that we don't have too many active connections. If we have,
610 * something must be dropped. It's not clear what will happen if we allow
611 * "too many" connections, but when dealing with network-facing software,
612 * we have to code defensively. Here we do that by imposing hard limits.
613 *
614 * There's no point in trying to do random drop here for DoS
615 * prevention. The NFS clients does 1 reconnect in 15 seconds. An
616 * attacker can easily beat that.
617 *
618 * The only somewhat efficient mechanism would be if drop old
619 * connections from the same IP first. But right now we don't even
620 * record the client IP in svc_sock.
621 *
622 * single-threaded services that expect a lot of clients will probably
623 * need to set sv_maxconn to override the default value which is based
624 * on the number of threads
625 */
626static void svc_check_conn_limits(struct svc_serv *serv)
627{
628 unsigned int limit = serv->sv_maxconn ? serv->sv_maxconn :
629 (serv->sv_nrthreads+3) * 20;
630
631 if (serv->sv_tmpcnt > limit) {
632 struct svc_xprt *xprt = NULL;
633 spin_lock_bh(&serv->sv_lock);
634 if (!list_empty(&serv->sv_tempsocks)) {
635 /* Try to help the admin */
636 net_notice_ratelimited("%s: too many open connections, consider increasing the %s\n",
637 serv->sv_name, serv->sv_maxconn ?
638 "max number of connections" :
639 "number of threads");
640 /*
641 * Always select the oldest connection. It's not fair,
642 * but so is life
643 */
644 xprt = list_entry(serv->sv_tempsocks.prev,
645 struct svc_xprt,
646 xpt_list);
647 set_bit(XPT_CLOSE, &xprt->xpt_flags);
648 svc_xprt_get(xprt);
649 }
650 spin_unlock_bh(&serv->sv_lock);
651
652 if (xprt) {
653 svc_xprt_enqueue(xprt);
654 svc_xprt_put(xprt);
655 }
656 }
657}
658
659static bool svc_alloc_arg(struct svc_rqst *rqstp)
660{
661 struct svc_serv *serv = rqstp->rq_server;
662 struct xdr_buf *arg = &rqstp->rq_arg;
663 unsigned long pages, filled, ret;
664
665 pages = (serv->sv_max_mesg + 2 * PAGE_SIZE) >> PAGE_SHIFT;
666 if (pages > RPCSVC_MAXPAGES) {
667 pr_warn_once("svc: warning: pages=%lu > RPCSVC_MAXPAGES=%lu\n",
668 pages, RPCSVC_MAXPAGES);
669 /* use as many pages as possible */
670 pages = RPCSVC_MAXPAGES;
671 }
672
673 for (filled = 0; filled < pages; filled = ret) {
674 ret = alloc_pages_bulk_array(GFP_KERNEL, pages,
675 rqstp->rq_pages);
676 if (ret > filled)
677 /* Made progress, don't sleep yet */
678 continue;
679
680 set_current_state(TASK_IDLE);
681 if (svc_thread_should_stop(rqstp)) {
682 set_current_state(TASK_RUNNING);
683 return false;
684 }
685 trace_svc_alloc_arg_err(pages, ret);
686 memalloc_retry_wait(GFP_KERNEL);
687 }
688 rqstp->rq_page_end = &rqstp->rq_pages[pages];
689 rqstp->rq_pages[pages] = NULL; /* this might be seen in nfsd_splice_actor() */
690
691 /* Make arg->head point to first page and arg->pages point to rest */
692 arg->head[0].iov_base = page_address(rqstp->rq_pages[0]);
693 arg->head[0].iov_len = PAGE_SIZE;
694 arg->pages = rqstp->rq_pages + 1;
695 arg->page_base = 0;
696 /* save at least one page for response */
697 arg->page_len = (pages-2)*PAGE_SIZE;
698 arg->len = (pages-1)*PAGE_SIZE;
699 arg->tail[0].iov_len = 0;
700
701 rqstp->rq_xid = xdr_zero;
702 return true;
703}
704
705static bool
706svc_thread_should_sleep(struct svc_rqst *rqstp)
707{
708 struct svc_pool *pool = rqstp->rq_pool;
709
710 /* did someone call svc_wake_up? */
711 if (test_bit(SP_TASK_PENDING, &pool->sp_flags))
712 return false;
713
714 /* was a socket queued? */
715 if (!lwq_empty(&pool->sp_xprts))
716 return false;
717
718 /* are we shutting down? */
719 if (svc_thread_should_stop(rqstp))
720 return false;
721
722#if defined(CONFIG_SUNRPC_BACKCHANNEL)
723 if (svc_is_backchannel(rqstp)) {
724 if (!lwq_empty(&rqstp->rq_server->sv_cb_list))
725 return false;
726 }
727#endif
728
729 return true;
730}
731
732static void svc_thread_wait_for_work(struct svc_rqst *rqstp)
733{
734 struct svc_pool *pool = rqstp->rq_pool;
735
736 if (svc_thread_should_sleep(rqstp)) {
737 set_current_state(TASK_IDLE | TASK_FREEZABLE);
738 llist_add(&rqstp->rq_idle, &pool->sp_idle_threads);
739 if (likely(svc_thread_should_sleep(rqstp)))
740 schedule();
741
742 while (!llist_del_first_this(&pool->sp_idle_threads,
743 &rqstp->rq_idle)) {
744 /* Work just became available. This thread can only
745 * handle it after removing rqstp from the idle
746 * list. If that attempt failed, some other thread
747 * must have queued itself after finding no
748 * work to do, so that thread has taken responsibly
749 * for this new work. This thread can safely sleep
750 * until woken again.
751 */
752 schedule();
753 set_current_state(TASK_IDLE | TASK_FREEZABLE);
754 }
755 __set_current_state(TASK_RUNNING);
756 } else {
757 cond_resched();
758 }
759 try_to_freeze();
760}
761
762static void svc_add_new_temp_xprt(struct svc_serv *serv, struct svc_xprt *newxpt)
763{
764 spin_lock_bh(&serv->sv_lock);
765 set_bit(XPT_TEMP, &newxpt->xpt_flags);
766 list_add(&newxpt->xpt_list, &serv->sv_tempsocks);
767 serv->sv_tmpcnt++;
768 if (serv->sv_temptimer.function == NULL) {
769 /* setup timer to age temp transports */
770 serv->sv_temptimer.function = svc_age_temp_xprts;
771 mod_timer(&serv->sv_temptimer,
772 jiffies + svc_conn_age_period * HZ);
773 }
774 spin_unlock_bh(&serv->sv_lock);
775 svc_xprt_received(newxpt);
776}
777
778static void svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
779{
780 struct svc_serv *serv = rqstp->rq_server;
781 int len = 0;
782
783 if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) {
784 if (test_and_clear_bit(XPT_KILL_TEMP, &xprt->xpt_flags))
785 xprt->xpt_ops->xpo_kill_temp_xprt(xprt);
786 svc_delete_xprt(xprt);
787 /* Leave XPT_BUSY set on the dead xprt: */
788 goto out;
789 }
790 if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) {
791 struct svc_xprt *newxpt;
792 /*
793 * We know this module_get will succeed because the
794 * listener holds a reference too
795 */
796 __module_get(xprt->xpt_class->xcl_owner);
797 svc_check_conn_limits(xprt->xpt_server);
798 newxpt = xprt->xpt_ops->xpo_accept(xprt);
799 if (newxpt) {
800 newxpt->xpt_cred = get_cred(xprt->xpt_cred);
801 svc_add_new_temp_xprt(serv, newxpt);
802 trace_svc_xprt_accept(newxpt, serv->sv_name);
803 } else {
804 module_put(xprt->xpt_class->xcl_owner);
805 }
806 svc_xprt_received(xprt);
807 } else if (test_bit(XPT_HANDSHAKE, &xprt->xpt_flags)) {
808 xprt->xpt_ops->xpo_handshake(xprt);
809 svc_xprt_received(xprt);
810 } else if (svc_xprt_reserve_slot(rqstp, xprt)) {
811 /* XPT_DATA|XPT_DEFERRED case: */
812 rqstp->rq_deferred = svc_deferred_dequeue(xprt);
813 if (rqstp->rq_deferred)
814 len = svc_deferred_recv(rqstp);
815 else
816 len = xprt->xpt_ops->xpo_recvfrom(rqstp);
817 rqstp->rq_reserved = serv->sv_max_mesg;
818 atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
819 if (len <= 0)
820 goto out;
821
822 trace_svc_xdr_recvfrom(&rqstp->rq_arg);
823
824 clear_bit(XPT_OLD, &xprt->xpt_flags);
825
826 rqstp->rq_chandle.defer = svc_defer;
827
828 if (serv->sv_stats)
829 serv->sv_stats->netcnt++;
830 percpu_counter_inc(&rqstp->rq_pool->sp_messages_arrived);
831 rqstp->rq_stime = ktime_get();
832 svc_process(rqstp);
833 } else
834 svc_xprt_received(xprt);
835
836out:
837 rqstp->rq_res.len = 0;
838 svc_xprt_release(rqstp);
839}
840
841static void svc_thread_wake_next(struct svc_rqst *rqstp)
842{
843 if (!svc_thread_should_sleep(rqstp))
844 /* More work pending after I dequeued some,
845 * wake another worker
846 */
847 svc_pool_wake_idle_thread(rqstp->rq_pool);
848}
849
850/**
851 * svc_recv - Receive and process the next request on any transport
852 * @rqstp: an idle RPC service thread
853 *
854 * This code is carefully organised not to touch any cachelines in
855 * the shared svc_serv structure, only cachelines in the local
856 * svc_pool.
857 */
858void svc_recv(struct svc_rqst *rqstp)
859{
860 struct svc_pool *pool = rqstp->rq_pool;
861
862 if (!svc_alloc_arg(rqstp))
863 return;
864
865 svc_thread_wait_for_work(rqstp);
866
867 clear_bit(SP_TASK_PENDING, &pool->sp_flags);
868
869 if (svc_thread_should_stop(rqstp)) {
870 svc_thread_wake_next(rqstp);
871 return;
872 }
873
874 rqstp->rq_xprt = svc_xprt_dequeue(pool);
875 if (rqstp->rq_xprt) {
876 struct svc_xprt *xprt = rqstp->rq_xprt;
877
878 svc_thread_wake_next(rqstp);
879 /* Normally we will wait up to 5 seconds for any required
880 * cache information to be provided. When there are no
881 * idle threads, we reduce the wait time.
882 */
883 if (pool->sp_idle_threads.first)
884 rqstp->rq_chandle.thread_wait = 5 * HZ;
885 else
886 rqstp->rq_chandle.thread_wait = 1 * HZ;
887
888 trace_svc_xprt_dequeue(rqstp);
889 svc_handle_xprt(rqstp, xprt);
890 }
891
892#if defined(CONFIG_SUNRPC_BACKCHANNEL)
893 if (svc_is_backchannel(rqstp)) {
894 struct svc_serv *serv = rqstp->rq_server;
895 struct rpc_rqst *req;
896
897 req = lwq_dequeue(&serv->sv_cb_list,
898 struct rpc_rqst, rq_bc_list);
899 if (req) {
900 svc_thread_wake_next(rqstp);
901 svc_process_bc(req, rqstp);
902 }
903 }
904#endif
905}
906EXPORT_SYMBOL_GPL(svc_recv);
907
908/**
909 * svc_send - Return reply to client
910 * @rqstp: RPC transaction context
911 *
912 */
913void svc_send(struct svc_rqst *rqstp)
914{
915 struct svc_xprt *xprt;
916 struct xdr_buf *xb;
917 int status;
918
919 xprt = rqstp->rq_xprt;
920
921 /* calculate over-all length */
922 xb = &rqstp->rq_res;
923 xb->len = xb->head[0].iov_len +
924 xb->page_len +
925 xb->tail[0].iov_len;
926 trace_svc_xdr_sendto(rqstp->rq_xid, xb);
927 trace_svc_stats_latency(rqstp);
928
929 status = xprt->xpt_ops->xpo_sendto(rqstp);
930
931 trace_svc_send(rqstp, status);
932}
933
934/*
935 * Timer function to close old temporary transports, using
936 * a mark-and-sweep algorithm.
937 */
938static void svc_age_temp_xprts(struct timer_list *t)
939{
940 struct svc_serv *serv = from_timer(serv, t, sv_temptimer);
941 struct svc_xprt *xprt;
942 struct list_head *le, *next;
943
944 dprintk("svc_age_temp_xprts\n");
945
946 if (!spin_trylock_bh(&serv->sv_lock)) {
947 /* busy, try again 1 sec later */
948 dprintk("svc_age_temp_xprts: busy\n");
949 mod_timer(&serv->sv_temptimer, jiffies + HZ);
950 return;
951 }
952
953 list_for_each_safe(le, next, &serv->sv_tempsocks) {
954 xprt = list_entry(le, struct svc_xprt, xpt_list);
955
956 /* First time through, just mark it OLD. Second time
957 * through, close it. */
958 if (!test_and_set_bit(XPT_OLD, &xprt->xpt_flags))
959 continue;
960 if (kref_read(&xprt->xpt_ref) > 1 ||
961 test_bit(XPT_BUSY, &xprt->xpt_flags))
962 continue;
963 list_del_init(le);
964 set_bit(XPT_CLOSE, &xprt->xpt_flags);
965 dprintk("queuing xprt %p for closing\n", xprt);
966
967 /* a thread will dequeue and close it soon */
968 svc_xprt_enqueue(xprt);
969 }
970 spin_unlock_bh(&serv->sv_lock);
971
972 mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ);
973}
974
975/* Close temporary transports whose xpt_local matches server_addr immediately
976 * instead of waiting for them to be picked up by the timer.
977 *
978 * This is meant to be called from a notifier_block that runs when an ip
979 * address is deleted.
980 */
981void svc_age_temp_xprts_now(struct svc_serv *serv, struct sockaddr *server_addr)
982{
983 struct svc_xprt *xprt;
984 struct list_head *le, *next;
985 LIST_HEAD(to_be_closed);
986
987 spin_lock_bh(&serv->sv_lock);
988 list_for_each_safe(le, next, &serv->sv_tempsocks) {
989 xprt = list_entry(le, struct svc_xprt, xpt_list);
990 if (rpc_cmp_addr(server_addr, (struct sockaddr *)
991 &xprt->xpt_local)) {
992 dprintk("svc_age_temp_xprts_now: found %p\n", xprt);
993 list_move(le, &to_be_closed);
994 }
995 }
996 spin_unlock_bh(&serv->sv_lock);
997
998 while (!list_empty(&to_be_closed)) {
999 le = to_be_closed.next;
1000 list_del_init(le);
1001 xprt = list_entry(le, struct svc_xprt, xpt_list);
1002 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1003 set_bit(XPT_KILL_TEMP, &xprt->xpt_flags);
1004 dprintk("svc_age_temp_xprts_now: queuing xprt %p for closing\n",
1005 xprt);
1006 svc_xprt_enqueue(xprt);
1007 }
1008}
1009EXPORT_SYMBOL_GPL(svc_age_temp_xprts_now);
1010
1011static void call_xpt_users(struct svc_xprt *xprt)
1012{
1013 struct svc_xpt_user *u;
1014
1015 spin_lock(&xprt->xpt_lock);
1016 while (!list_empty(&xprt->xpt_users)) {
1017 u = list_first_entry(&xprt->xpt_users, struct svc_xpt_user, list);
1018 list_del_init(&u->list);
1019 u->callback(u);
1020 }
1021 spin_unlock(&xprt->xpt_lock);
1022}
1023
1024/*
1025 * Remove a dead transport
1026 */
1027static void svc_delete_xprt(struct svc_xprt *xprt)
1028{
1029 struct svc_serv *serv = xprt->xpt_server;
1030 struct svc_deferred_req *dr;
1031
1032 if (test_and_set_bit(XPT_DEAD, &xprt->xpt_flags))
1033 return;
1034
1035 trace_svc_xprt_detach(xprt);
1036 xprt->xpt_ops->xpo_detach(xprt);
1037 if (xprt->xpt_bc_xprt)
1038 xprt->xpt_bc_xprt->ops->close(xprt->xpt_bc_xprt);
1039
1040 spin_lock_bh(&serv->sv_lock);
1041 list_del_init(&xprt->xpt_list);
1042 if (test_bit(XPT_TEMP, &xprt->xpt_flags))
1043 serv->sv_tmpcnt--;
1044 spin_unlock_bh(&serv->sv_lock);
1045
1046 while ((dr = svc_deferred_dequeue(xprt)) != NULL)
1047 free_deferred(xprt, dr);
1048
1049 call_xpt_users(xprt);
1050 svc_xprt_put(xprt);
1051}
1052
1053/**
1054 * svc_xprt_close - Close a client connection
1055 * @xprt: transport to disconnect
1056 *
1057 */
1058void svc_xprt_close(struct svc_xprt *xprt)
1059{
1060 trace_svc_xprt_close(xprt);
1061 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1062 if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
1063 /* someone else will have to effect the close */
1064 return;
1065 /*
1066 * We expect svc_close_xprt() to work even when no threads are
1067 * running (e.g., while configuring the server before starting
1068 * any threads), so if the transport isn't busy, we delete
1069 * it ourself:
1070 */
1071 svc_delete_xprt(xprt);
1072}
1073EXPORT_SYMBOL_GPL(svc_xprt_close);
1074
1075static int svc_close_list(struct svc_serv *serv, struct list_head *xprt_list, struct net *net)
1076{
1077 struct svc_xprt *xprt;
1078 int ret = 0;
1079
1080 spin_lock_bh(&serv->sv_lock);
1081 list_for_each_entry(xprt, xprt_list, xpt_list) {
1082 if (xprt->xpt_net != net)
1083 continue;
1084 ret++;
1085 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1086 svc_xprt_enqueue(xprt);
1087 }
1088 spin_unlock_bh(&serv->sv_lock);
1089 return ret;
1090}
1091
1092static void svc_clean_up_xprts(struct svc_serv *serv, struct net *net)
1093{
1094 struct svc_xprt *xprt;
1095 int i;
1096
1097 for (i = 0; i < serv->sv_nrpools; i++) {
1098 struct svc_pool *pool = &serv->sv_pools[i];
1099 struct llist_node *q, **t1, *t2;
1100
1101 q = lwq_dequeue_all(&pool->sp_xprts);
1102 lwq_for_each_safe(xprt, t1, t2, &q, xpt_ready) {
1103 if (xprt->xpt_net == net) {
1104 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1105 svc_delete_xprt(xprt);
1106 xprt = NULL;
1107 }
1108 }
1109
1110 if (q)
1111 lwq_enqueue_batch(q, &pool->sp_xprts);
1112 }
1113}
1114
1115/**
1116 * svc_xprt_destroy_all - Destroy transports associated with @serv
1117 * @serv: RPC service to be shut down
1118 * @net: target network namespace
1119 *
1120 * Server threads may still be running (especially in the case where the
1121 * service is still running in other network namespaces).
1122 *
1123 * So we shut down sockets the same way we would on a running server, by
1124 * setting XPT_CLOSE, enqueuing, and letting a thread pick it up to do
1125 * the close. In the case there are no such other threads,
1126 * threads running, svc_clean_up_xprts() does a simple version of a
1127 * server's main event loop, and in the case where there are other
1128 * threads, we may need to wait a little while and then check again to
1129 * see if they're done.
1130 */
1131void svc_xprt_destroy_all(struct svc_serv *serv, struct net *net)
1132{
1133 int delay = 0;
1134
1135 while (svc_close_list(serv, &serv->sv_permsocks, net) +
1136 svc_close_list(serv, &serv->sv_tempsocks, net)) {
1137
1138 svc_clean_up_xprts(serv, net);
1139 msleep(delay++);
1140 }
1141}
1142EXPORT_SYMBOL_GPL(svc_xprt_destroy_all);
1143
1144/*
1145 * Handle defer and revisit of requests
1146 */
1147
1148static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
1149{
1150 struct svc_deferred_req *dr =
1151 container_of(dreq, struct svc_deferred_req, handle);
1152 struct svc_xprt *xprt = dr->xprt;
1153
1154 spin_lock(&xprt->xpt_lock);
1155 set_bit(XPT_DEFERRED, &xprt->xpt_flags);
1156 if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) {
1157 spin_unlock(&xprt->xpt_lock);
1158 trace_svc_defer_drop(dr);
1159 free_deferred(xprt, dr);
1160 svc_xprt_put(xprt);
1161 return;
1162 }
1163 dr->xprt = NULL;
1164 list_add(&dr->handle.recent, &xprt->xpt_deferred);
1165 spin_unlock(&xprt->xpt_lock);
1166 trace_svc_defer_queue(dr);
1167 svc_xprt_enqueue(xprt);
1168 svc_xprt_put(xprt);
1169}
1170
1171/*
1172 * Save the request off for later processing. The request buffer looks
1173 * like this:
1174 *
1175 * <xprt-header><rpc-header><rpc-pagelist><rpc-tail>
1176 *
1177 * This code can only handle requests that consist of an xprt-header
1178 * and rpc-header.
1179 */
1180static struct cache_deferred_req *svc_defer(struct cache_req *req)
1181{
1182 struct svc_rqst *rqstp = container_of(req, struct svc_rqst, rq_chandle);
1183 struct svc_deferred_req *dr;
1184
1185 if (rqstp->rq_arg.page_len || !test_bit(RQ_USEDEFERRAL, &rqstp->rq_flags))
1186 return NULL; /* if more than a page, give up FIXME */
1187 if (rqstp->rq_deferred) {
1188 dr = rqstp->rq_deferred;
1189 rqstp->rq_deferred = NULL;
1190 } else {
1191 size_t skip;
1192 size_t size;
1193 /* FIXME maybe discard if size too large */
1194 size = sizeof(struct svc_deferred_req) + rqstp->rq_arg.len;
1195 dr = kmalloc(size, GFP_KERNEL);
1196 if (dr == NULL)
1197 return NULL;
1198
1199 dr->handle.owner = rqstp->rq_server;
1200 dr->prot = rqstp->rq_prot;
1201 memcpy(&dr->addr, &rqstp->rq_addr, rqstp->rq_addrlen);
1202 dr->addrlen = rqstp->rq_addrlen;
1203 dr->daddr = rqstp->rq_daddr;
1204 dr->argslen = rqstp->rq_arg.len >> 2;
1205
1206 /* back up head to the start of the buffer and copy */
1207 skip = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len;
1208 memcpy(dr->args, rqstp->rq_arg.head[0].iov_base - skip,
1209 dr->argslen << 2);
1210 }
1211 dr->xprt_ctxt = rqstp->rq_xprt_ctxt;
1212 rqstp->rq_xprt_ctxt = NULL;
1213 trace_svc_defer(rqstp);
1214 svc_xprt_get(rqstp->rq_xprt);
1215 dr->xprt = rqstp->rq_xprt;
1216 set_bit(RQ_DROPME, &rqstp->rq_flags);
1217
1218 dr->handle.revisit = svc_revisit;
1219 return &dr->handle;
1220}
1221
1222/*
1223 * recv data from a deferred request into an active one
1224 */
1225static noinline int svc_deferred_recv(struct svc_rqst *rqstp)
1226{
1227 struct svc_deferred_req *dr = rqstp->rq_deferred;
1228
1229 trace_svc_defer_recv(dr);
1230
1231 /* setup iov_base past transport header */
1232 rqstp->rq_arg.head[0].iov_base = dr->args;
1233 /* The iov_len does not include the transport header bytes */
1234 rqstp->rq_arg.head[0].iov_len = dr->argslen << 2;
1235 rqstp->rq_arg.page_len = 0;
1236 /* The rq_arg.len includes the transport header bytes */
1237 rqstp->rq_arg.len = dr->argslen << 2;
1238 rqstp->rq_prot = dr->prot;
1239 memcpy(&rqstp->rq_addr, &dr->addr, dr->addrlen);
1240 rqstp->rq_addrlen = dr->addrlen;
1241 /* Save off transport header len in case we get deferred again */
1242 rqstp->rq_daddr = dr->daddr;
1243 rqstp->rq_respages = rqstp->rq_pages;
1244 rqstp->rq_xprt_ctxt = dr->xprt_ctxt;
1245
1246 dr->xprt_ctxt = NULL;
1247 svc_xprt_received(rqstp->rq_xprt);
1248 return dr->argslen << 2;
1249}
1250
1251
1252static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt)
1253{
1254 struct svc_deferred_req *dr = NULL;
1255
1256 if (!test_bit(XPT_DEFERRED, &xprt->xpt_flags))
1257 return NULL;
1258 spin_lock(&xprt->xpt_lock);
1259 if (!list_empty(&xprt->xpt_deferred)) {
1260 dr = list_entry(xprt->xpt_deferred.next,
1261 struct svc_deferred_req,
1262 handle.recent);
1263 list_del_init(&dr->handle.recent);
1264 } else
1265 clear_bit(XPT_DEFERRED, &xprt->xpt_flags);
1266 spin_unlock(&xprt->xpt_lock);
1267 return dr;
1268}
1269
1270/**
1271 * svc_find_listener - find an RPC transport instance
1272 * @serv: pointer to svc_serv to search
1273 * @xcl_name: C string containing transport's class name
1274 * @net: owner net pointer
1275 * @sa: sockaddr containing address
1276 *
1277 * Return the transport instance pointer for the endpoint accepting
1278 * connections/peer traffic from the specified transport class,
1279 * and matching sockaddr.
1280 */
1281struct svc_xprt *svc_find_listener(struct svc_serv *serv, const char *xcl_name,
1282 struct net *net, const struct sockaddr *sa)
1283{
1284 struct svc_xprt *xprt;
1285 struct svc_xprt *found = NULL;
1286
1287 spin_lock_bh(&serv->sv_lock);
1288 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1289 if (xprt->xpt_net != net)
1290 continue;
1291 if (strcmp(xprt->xpt_class->xcl_name, xcl_name))
1292 continue;
1293 if (!rpc_cmp_addr_port(sa, (struct sockaddr *)&xprt->xpt_local))
1294 continue;
1295 found = xprt;
1296 svc_xprt_get(xprt);
1297 break;
1298 }
1299 spin_unlock_bh(&serv->sv_lock);
1300 return found;
1301}
1302EXPORT_SYMBOL_GPL(svc_find_listener);
1303
1304/**
1305 * svc_find_xprt - find an RPC transport instance
1306 * @serv: pointer to svc_serv to search
1307 * @xcl_name: C string containing transport's class name
1308 * @net: owner net pointer
1309 * @af: Address family of transport's local address
1310 * @port: transport's IP port number
1311 *
1312 * Return the transport instance pointer for the endpoint accepting
1313 * connections/peer traffic from the specified transport class,
1314 * address family and port.
1315 *
1316 * Specifying 0 for the address family or port is effectively a
1317 * wild-card, and will result in matching the first transport in the
1318 * service's list that has a matching class name.
1319 */
1320struct svc_xprt *svc_find_xprt(struct svc_serv *serv, const char *xcl_name,
1321 struct net *net, const sa_family_t af,
1322 const unsigned short port)
1323{
1324 struct svc_xprt *xprt;
1325 struct svc_xprt *found = NULL;
1326
1327 /* Sanity check the args */
1328 if (serv == NULL || xcl_name == NULL)
1329 return found;
1330
1331 spin_lock_bh(&serv->sv_lock);
1332 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1333 if (xprt->xpt_net != net)
1334 continue;
1335 if (strcmp(xprt->xpt_class->xcl_name, xcl_name))
1336 continue;
1337 if (af != AF_UNSPEC && af != xprt->xpt_local.ss_family)
1338 continue;
1339 if (port != 0 && port != svc_xprt_local_port(xprt))
1340 continue;
1341 found = xprt;
1342 svc_xprt_get(xprt);
1343 break;
1344 }
1345 spin_unlock_bh(&serv->sv_lock);
1346 return found;
1347}
1348EXPORT_SYMBOL_GPL(svc_find_xprt);
1349
1350static int svc_one_xprt_name(const struct svc_xprt *xprt,
1351 char *pos, int remaining)
1352{
1353 int len;
1354
1355 len = snprintf(pos, remaining, "%s %u\n",
1356 xprt->xpt_class->xcl_name,
1357 svc_xprt_local_port(xprt));
1358 if (len >= remaining)
1359 return -ENAMETOOLONG;
1360 return len;
1361}
1362
1363/**
1364 * svc_xprt_names - format a buffer with a list of transport names
1365 * @serv: pointer to an RPC service
1366 * @buf: pointer to a buffer to be filled in
1367 * @buflen: length of buffer to be filled in
1368 *
1369 * Fills in @buf with a string containing a list of transport names,
1370 * each name terminated with '\n'.
1371 *
1372 * Returns positive length of the filled-in string on success; otherwise
1373 * a negative errno value is returned if an error occurs.
1374 */
1375int svc_xprt_names(struct svc_serv *serv, char *buf, const int buflen)
1376{
1377 struct svc_xprt *xprt;
1378 int len, totlen;
1379 char *pos;
1380
1381 /* Sanity check args */
1382 if (!serv)
1383 return 0;
1384
1385 spin_lock_bh(&serv->sv_lock);
1386
1387 pos = buf;
1388 totlen = 0;
1389 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1390 len = svc_one_xprt_name(xprt, pos, buflen - totlen);
1391 if (len < 0) {
1392 *buf = '\0';
1393 totlen = len;
1394 }
1395 if (len <= 0)
1396 break;
1397
1398 pos += len;
1399 totlen += len;
1400 }
1401
1402 spin_unlock_bh(&serv->sv_lock);
1403 return totlen;
1404}
1405EXPORT_SYMBOL_GPL(svc_xprt_names);
1406
1407/*----------------------------------------------------------------------------*/
1408
1409static void *svc_pool_stats_start(struct seq_file *m, loff_t *pos)
1410{
1411 unsigned int pidx = (unsigned int)*pos;
1412 struct svc_info *si = m->private;
1413
1414 dprintk("svc_pool_stats_start, *pidx=%u\n", pidx);
1415
1416 mutex_lock(si->mutex);
1417
1418 if (!pidx)
1419 return SEQ_START_TOKEN;
1420 if (!si->serv)
1421 return NULL;
1422 return pidx > si->serv->sv_nrpools ? NULL
1423 : &si->serv->sv_pools[pidx - 1];
1424}
1425
1426static void *svc_pool_stats_next(struct seq_file *m, void *p, loff_t *pos)
1427{
1428 struct svc_pool *pool = p;
1429 struct svc_info *si = m->private;
1430 struct svc_serv *serv = si->serv;
1431
1432 dprintk("svc_pool_stats_next, *pos=%llu\n", *pos);
1433
1434 if (!serv) {
1435 pool = NULL;
1436 } else if (p == SEQ_START_TOKEN) {
1437 pool = &serv->sv_pools[0];
1438 } else {
1439 unsigned int pidx = (pool - &serv->sv_pools[0]);
1440 if (pidx < serv->sv_nrpools-1)
1441 pool = &serv->sv_pools[pidx+1];
1442 else
1443 pool = NULL;
1444 }
1445 ++*pos;
1446 return pool;
1447}
1448
1449static void svc_pool_stats_stop(struct seq_file *m, void *p)
1450{
1451 struct svc_info *si = m->private;
1452
1453 mutex_unlock(si->mutex);
1454}
1455
1456static int svc_pool_stats_show(struct seq_file *m, void *p)
1457{
1458 struct svc_pool *pool = p;
1459
1460 if (p == SEQ_START_TOKEN) {
1461 seq_puts(m, "# pool packets-arrived sockets-enqueued threads-woken threads-timedout\n");
1462 return 0;
1463 }
1464
1465 seq_printf(m, "%u %llu %llu %llu 0\n",
1466 pool->sp_id,
1467 percpu_counter_sum_positive(&pool->sp_messages_arrived),
1468 percpu_counter_sum_positive(&pool->sp_sockets_queued),
1469 percpu_counter_sum_positive(&pool->sp_threads_woken));
1470
1471 return 0;
1472}
1473
1474static const struct seq_operations svc_pool_stats_seq_ops = {
1475 .start = svc_pool_stats_start,
1476 .next = svc_pool_stats_next,
1477 .stop = svc_pool_stats_stop,
1478 .show = svc_pool_stats_show,
1479};
1480
1481int svc_pool_stats_open(struct svc_info *info, struct file *file)
1482{
1483 struct seq_file *seq;
1484 int err;
1485
1486 err = seq_open(file, &svc_pool_stats_seq_ops);
1487 if (err)
1488 return err;
1489 seq = file->private_data;
1490 seq->private = info;
1491
1492 return 0;
1493}
1494EXPORT_SYMBOL(svc_pool_stats_open);
1495
1496/*----------------------------------------------------------------------------*/