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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/kthread.h>
13#include <linux/slab.h>
14#include <net/sock.h>
15#include <linux/sunrpc/addr.h>
16#include <linux/sunrpc/stats.h>
17#include <linux/sunrpc/svc_xprt.h>
18#include <linux/sunrpc/svcsock.h>
19#include <linux/sunrpc/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_pool->sp_lock protects most of the fields of that pool.
50 * svc_serv->sv_lock protects sv_tempsocks, sv_permsocks, sv_tmpcnt.
51 * when both need to be taken (rare), svc_serv->sv_lock is first.
52 * The "service mutex" protects svc_serv->sv_nrthread.
53 * svc_sock->sk_lock protects the svc_sock->sk_deferred list
54 * and the ->sk_info_authunix cache.
55 *
56 * The XPT_BUSY bit in xprt->xpt_flags prevents a transport being
57 * enqueued multiply. During normal transport processing this bit
58 * is set by svc_xprt_enqueue and cleared by svc_xprt_received.
59 * Providers should not manipulate this bit directly.
60 *
61 * Some flags can be set to certain values at any time
62 * providing that certain rules are followed:
63 *
64 * XPT_CONN, XPT_DATA:
65 * - Can be set or cleared at any time.
66 * - After a set, svc_xprt_enqueue must be called to enqueue
67 * the transport for processing.
68 * - After a clear, the transport must be read/accepted.
69 * If this succeeds, it must be set again.
70 * XPT_CLOSE:
71 * - Can set at any time. It is never cleared.
72 * XPT_DEAD:
73 * - Can only be set while XPT_BUSY is held which ensures
74 * that no other thread will be using the transport or will
75 * try to set XPT_DEAD.
76 */
77int svc_reg_xprt_class(struct svc_xprt_class *xcl)
78{
79 struct svc_xprt_class *cl;
80 int res = -EEXIST;
81
82 dprintk("svc: Adding svc transport class '%s'\n", xcl->xcl_name);
83
84 INIT_LIST_HEAD(&xcl->xcl_list);
85 spin_lock(&svc_xprt_class_lock);
86 /* Make sure there isn't already a class with the same name */
87 list_for_each_entry(cl, &svc_xprt_class_list, xcl_list) {
88 if (strcmp(xcl->xcl_name, cl->xcl_name) == 0)
89 goto out;
90 }
91 list_add_tail(&xcl->xcl_list, &svc_xprt_class_list);
92 res = 0;
93out:
94 spin_unlock(&svc_xprt_class_lock);
95 return res;
96}
97EXPORT_SYMBOL_GPL(svc_reg_xprt_class);
98
99void svc_unreg_xprt_class(struct svc_xprt_class *xcl)
100{
101 dprintk("svc: Removing svc transport class '%s'\n", xcl->xcl_name);
102 spin_lock(&svc_xprt_class_lock);
103 list_del_init(&xcl->xcl_list);
104 spin_unlock(&svc_xprt_class_lock);
105}
106EXPORT_SYMBOL_GPL(svc_unreg_xprt_class);
107
108/**
109 * svc_print_xprts - Format the transport list for printing
110 * @buf: target buffer for formatted address
111 * @maxlen: length of target buffer
112 *
113 * Fills in @buf with a string containing a list of transport names, each name
114 * terminated with '\n'. If the buffer is too small, some entries may be
115 * missing, but it is guaranteed that all lines in the output buffer are
116 * complete.
117 *
118 * Returns positive length of the filled-in string.
119 */
120int svc_print_xprts(char *buf, int maxlen)
121{
122 struct svc_xprt_class *xcl;
123 char tmpstr[80];
124 int len = 0;
125 buf[0] = '\0';
126
127 spin_lock(&svc_xprt_class_lock);
128 list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
129 int slen;
130
131 slen = snprintf(tmpstr, sizeof(tmpstr), "%s %d\n",
132 xcl->xcl_name, xcl->xcl_max_payload);
133 if (slen >= sizeof(tmpstr) || len + slen >= maxlen)
134 break;
135 len += slen;
136 strcat(buf, tmpstr);
137 }
138 spin_unlock(&svc_xprt_class_lock);
139
140 return len;
141}
142
143/**
144 * svc_xprt_deferred_close - Close a transport
145 * @xprt: transport instance
146 *
147 * Used in contexts that need to defer the work of shutting down
148 * the transport to an nfsd thread.
149 */
150void svc_xprt_deferred_close(struct svc_xprt *xprt)
151{
152 if (!test_and_set_bit(XPT_CLOSE, &xprt->xpt_flags))
153 svc_xprt_enqueue(xprt);
154}
155EXPORT_SYMBOL_GPL(svc_xprt_deferred_close);
156
157static void svc_xprt_free(struct kref *kref)
158{
159 struct svc_xprt *xprt =
160 container_of(kref, struct svc_xprt, xpt_ref);
161 struct module *owner = xprt->xpt_class->xcl_owner;
162 if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags))
163 svcauth_unix_info_release(xprt);
164 put_cred(xprt->xpt_cred);
165 put_net_track(xprt->xpt_net, &xprt->ns_tracker);
166 /* See comment on corresponding get in xs_setup_bc_tcp(): */
167 if (xprt->xpt_bc_xprt)
168 xprt_put(xprt->xpt_bc_xprt);
169 if (xprt->xpt_bc_xps)
170 xprt_switch_put(xprt->xpt_bc_xps);
171 trace_svc_xprt_free(xprt);
172 xprt->xpt_ops->xpo_free(xprt);
173 module_put(owner);
174}
175
176void svc_xprt_put(struct svc_xprt *xprt)
177{
178 kref_put(&xprt->xpt_ref, svc_xprt_free);
179}
180EXPORT_SYMBOL_GPL(svc_xprt_put);
181
182/*
183 * Called by transport drivers to initialize the transport independent
184 * portion of the transport instance.
185 */
186void svc_xprt_init(struct net *net, struct svc_xprt_class *xcl,
187 struct svc_xprt *xprt, struct svc_serv *serv)
188{
189 memset(xprt, 0, sizeof(*xprt));
190 xprt->xpt_class = xcl;
191 xprt->xpt_ops = xcl->xcl_ops;
192 kref_init(&xprt->xpt_ref);
193 xprt->xpt_server = serv;
194 INIT_LIST_HEAD(&xprt->xpt_list);
195 INIT_LIST_HEAD(&xprt->xpt_ready);
196 INIT_LIST_HEAD(&xprt->xpt_deferred);
197 INIT_LIST_HEAD(&xprt->xpt_users);
198 mutex_init(&xprt->xpt_mutex);
199 spin_lock_init(&xprt->xpt_lock);
200 set_bit(XPT_BUSY, &xprt->xpt_flags);
201 xprt->xpt_net = get_net_track(net, &xprt->ns_tracker, GFP_ATOMIC);
202 strcpy(xprt->xpt_remotebuf, "uninitialized");
203}
204EXPORT_SYMBOL_GPL(svc_xprt_init);
205
206static struct svc_xprt *__svc_xpo_create(struct svc_xprt_class *xcl,
207 struct svc_serv *serv,
208 struct net *net,
209 const int family,
210 const unsigned short port,
211 int flags)
212{
213 struct sockaddr_in sin = {
214 .sin_family = AF_INET,
215 .sin_addr.s_addr = htonl(INADDR_ANY),
216 .sin_port = htons(port),
217 };
218#if IS_ENABLED(CONFIG_IPV6)
219 struct sockaddr_in6 sin6 = {
220 .sin6_family = AF_INET6,
221 .sin6_addr = IN6ADDR_ANY_INIT,
222 .sin6_port = htons(port),
223 };
224#endif
225 struct svc_xprt *xprt;
226 struct sockaddr *sap;
227 size_t len;
228
229 switch (family) {
230 case PF_INET:
231 sap = (struct sockaddr *)&sin;
232 len = sizeof(sin);
233 break;
234#if IS_ENABLED(CONFIG_IPV6)
235 case PF_INET6:
236 sap = (struct sockaddr *)&sin6;
237 len = sizeof(sin6);
238 break;
239#endif
240 default:
241 return ERR_PTR(-EAFNOSUPPORT);
242 }
243
244 xprt = xcl->xcl_ops->xpo_create(serv, net, sap, len, flags);
245 if (IS_ERR(xprt))
246 trace_svc_xprt_create_err(serv->sv_program->pg_name,
247 xcl->xcl_name, sap, len, xprt);
248 return xprt;
249}
250
251/**
252 * svc_xprt_received - start next receiver thread
253 * @xprt: controlling transport
254 *
255 * The caller must hold the XPT_BUSY bit and must
256 * not thereafter touch transport data.
257 *
258 * Note: XPT_DATA only gets cleared when a read-attempt finds no (or
259 * insufficient) data.
260 */
261void svc_xprt_received(struct svc_xprt *xprt)
262{
263 if (!test_bit(XPT_BUSY, &xprt->xpt_flags)) {
264 WARN_ONCE(1, "xprt=0x%p already busy!", xprt);
265 return;
266 }
267
268 /* As soon as we clear busy, the xprt could be closed and
269 * 'put', so we need a reference to call svc_xprt_enqueue with:
270 */
271 svc_xprt_get(xprt);
272 smp_mb__before_atomic();
273 clear_bit(XPT_BUSY, &xprt->xpt_flags);
274 svc_xprt_enqueue(xprt);
275 svc_xprt_put(xprt);
276}
277EXPORT_SYMBOL_GPL(svc_xprt_received);
278
279void svc_add_new_perm_xprt(struct svc_serv *serv, struct svc_xprt *new)
280{
281 clear_bit(XPT_TEMP, &new->xpt_flags);
282 spin_lock_bh(&serv->sv_lock);
283 list_add(&new->xpt_list, &serv->sv_permsocks);
284 spin_unlock_bh(&serv->sv_lock);
285 svc_xprt_received(new);
286}
287
288static int _svc_xprt_create(struct svc_serv *serv, const char *xprt_name,
289 struct net *net, const int family,
290 const unsigned short port, int flags,
291 const struct cred *cred)
292{
293 struct svc_xprt_class *xcl;
294
295 spin_lock(&svc_xprt_class_lock);
296 list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
297 struct svc_xprt *newxprt;
298 unsigned short newport;
299
300 if (strcmp(xprt_name, xcl->xcl_name))
301 continue;
302
303 if (!try_module_get(xcl->xcl_owner))
304 goto err;
305
306 spin_unlock(&svc_xprt_class_lock);
307 newxprt = __svc_xpo_create(xcl, serv, net, family, port, flags);
308 if (IS_ERR(newxprt)) {
309 module_put(xcl->xcl_owner);
310 return PTR_ERR(newxprt);
311 }
312 newxprt->xpt_cred = get_cred(cred);
313 svc_add_new_perm_xprt(serv, newxprt);
314 newport = svc_xprt_local_port(newxprt);
315 return newport;
316 }
317 err:
318 spin_unlock(&svc_xprt_class_lock);
319 /* This errno is exposed to user space. Provide a reasonable
320 * perror msg for a bad transport. */
321 return -EPROTONOSUPPORT;
322}
323
324/**
325 * svc_xprt_create - Add a new listener to @serv
326 * @serv: target RPC service
327 * @xprt_name: transport class name
328 * @net: network namespace
329 * @family: network address family
330 * @port: listener port
331 * @flags: SVC_SOCK flags
332 * @cred: credential to bind to this transport
333 *
334 * Return values:
335 * %0: New listener added successfully
336 * %-EPROTONOSUPPORT: Requested transport type not supported
337 */
338int svc_xprt_create(struct svc_serv *serv, const char *xprt_name,
339 struct net *net, const int family,
340 const unsigned short port, int flags,
341 const struct cred *cred)
342{
343 int err;
344
345 err = _svc_xprt_create(serv, xprt_name, net, family, port, flags, cred);
346 if (err == -EPROTONOSUPPORT) {
347 request_module("svc%s", xprt_name);
348 err = _svc_xprt_create(serv, xprt_name, net, family, port, flags, cred);
349 }
350 return err;
351}
352EXPORT_SYMBOL_GPL(svc_xprt_create);
353
354/*
355 * Copy the local and remote xprt addresses to the rqstp structure
356 */
357void svc_xprt_copy_addrs(struct svc_rqst *rqstp, struct svc_xprt *xprt)
358{
359 memcpy(&rqstp->rq_addr, &xprt->xpt_remote, xprt->xpt_remotelen);
360 rqstp->rq_addrlen = xprt->xpt_remotelen;
361
362 /*
363 * Destination address in request is needed for binding the
364 * source address in RPC replies/callbacks later.
365 */
366 memcpy(&rqstp->rq_daddr, &xprt->xpt_local, xprt->xpt_locallen);
367 rqstp->rq_daddrlen = xprt->xpt_locallen;
368}
369EXPORT_SYMBOL_GPL(svc_xprt_copy_addrs);
370
371/**
372 * svc_print_addr - Format rq_addr field for printing
373 * @rqstp: svc_rqst struct containing address to print
374 * @buf: target buffer for formatted address
375 * @len: length of target buffer
376 *
377 */
378char *svc_print_addr(struct svc_rqst *rqstp, char *buf, size_t len)
379{
380 return __svc_print_addr(svc_addr(rqstp), buf, len);
381}
382EXPORT_SYMBOL_GPL(svc_print_addr);
383
384static bool svc_xprt_slots_in_range(struct svc_xprt *xprt)
385{
386 unsigned int limit = svc_rpc_per_connection_limit;
387 int nrqsts = atomic_read(&xprt->xpt_nr_rqsts);
388
389 return limit == 0 || (nrqsts >= 0 && nrqsts < limit);
390}
391
392static bool svc_xprt_reserve_slot(struct svc_rqst *rqstp, struct svc_xprt *xprt)
393{
394 if (!test_bit(RQ_DATA, &rqstp->rq_flags)) {
395 if (!svc_xprt_slots_in_range(xprt))
396 return false;
397 atomic_inc(&xprt->xpt_nr_rqsts);
398 set_bit(RQ_DATA, &rqstp->rq_flags);
399 }
400 return true;
401}
402
403static void svc_xprt_release_slot(struct svc_rqst *rqstp)
404{
405 struct svc_xprt *xprt = rqstp->rq_xprt;
406 if (test_and_clear_bit(RQ_DATA, &rqstp->rq_flags)) {
407 atomic_dec(&xprt->xpt_nr_rqsts);
408 smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */
409 svc_xprt_enqueue(xprt);
410 }
411}
412
413static bool svc_xprt_ready(struct svc_xprt *xprt)
414{
415 unsigned long xpt_flags;
416
417 /*
418 * If another cpu has recently updated xpt_flags,
419 * sk_sock->flags, xpt_reserved, or xpt_nr_rqsts, we need to
420 * know about it; otherwise it's possible that both that cpu and
421 * this one could call svc_xprt_enqueue() without either
422 * svc_xprt_enqueue() recognizing that the conditions below
423 * are satisfied, and we could stall indefinitely:
424 */
425 smp_rmb();
426 xpt_flags = READ_ONCE(xprt->xpt_flags);
427
428 if (xpt_flags & BIT(XPT_BUSY))
429 return false;
430 if (xpt_flags & (BIT(XPT_CONN) | BIT(XPT_CLOSE)))
431 return true;
432 if (xpt_flags & (BIT(XPT_DATA) | BIT(XPT_DEFERRED))) {
433 if (xprt->xpt_ops->xpo_has_wspace(xprt) &&
434 svc_xprt_slots_in_range(xprt))
435 return true;
436 trace_svc_xprt_no_write_space(xprt);
437 return false;
438 }
439 return false;
440}
441
442/**
443 * svc_xprt_enqueue - Queue a transport on an idle nfsd thread
444 * @xprt: transport with data pending
445 *
446 */
447void svc_xprt_enqueue(struct svc_xprt *xprt)
448{
449 struct svc_pool *pool;
450 struct svc_rqst *rqstp = NULL;
451
452 if (!svc_xprt_ready(xprt))
453 return;
454
455 /* Mark transport as busy. It will remain in this state until
456 * the provider calls svc_xprt_received. We update XPT_BUSY
457 * atomically because it also guards against trying to enqueue
458 * the transport twice.
459 */
460 if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
461 return;
462
463 pool = svc_pool_for_cpu(xprt->xpt_server);
464
465 atomic_long_inc(&pool->sp_stats.packets);
466
467 spin_lock_bh(&pool->sp_lock);
468 list_add_tail(&xprt->xpt_ready, &pool->sp_sockets);
469 pool->sp_stats.sockets_queued++;
470 spin_unlock_bh(&pool->sp_lock);
471
472 /* find a thread for this xprt */
473 rcu_read_lock();
474 list_for_each_entry_rcu(rqstp, &pool->sp_all_threads, rq_all) {
475 if (test_and_set_bit(RQ_BUSY, &rqstp->rq_flags))
476 continue;
477 atomic_long_inc(&pool->sp_stats.threads_woken);
478 rqstp->rq_qtime = ktime_get();
479 wake_up_process(rqstp->rq_task);
480 goto out_unlock;
481 }
482 set_bit(SP_CONGESTED, &pool->sp_flags);
483 rqstp = NULL;
484out_unlock:
485 rcu_read_unlock();
486 trace_svc_xprt_enqueue(xprt, rqstp);
487}
488EXPORT_SYMBOL_GPL(svc_xprt_enqueue);
489
490/*
491 * Dequeue the first transport, if there is one.
492 */
493static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool)
494{
495 struct svc_xprt *xprt = NULL;
496
497 if (list_empty(&pool->sp_sockets))
498 goto out;
499
500 spin_lock_bh(&pool->sp_lock);
501 if (likely(!list_empty(&pool->sp_sockets))) {
502 xprt = list_first_entry(&pool->sp_sockets,
503 struct svc_xprt, xpt_ready);
504 list_del_init(&xprt->xpt_ready);
505 svc_xprt_get(xprt);
506 }
507 spin_unlock_bh(&pool->sp_lock);
508out:
509 return xprt;
510}
511
512/**
513 * svc_reserve - change the space reserved for the reply to a request.
514 * @rqstp: The request in question
515 * @space: new max space to reserve
516 *
517 * Each request reserves some space on the output queue of the transport
518 * to make sure the reply fits. This function reduces that reserved
519 * space to be the amount of space used already, plus @space.
520 *
521 */
522void svc_reserve(struct svc_rqst *rqstp, int space)
523{
524 struct svc_xprt *xprt = rqstp->rq_xprt;
525
526 space += rqstp->rq_res.head[0].iov_len;
527
528 if (xprt && space < rqstp->rq_reserved) {
529 atomic_sub((rqstp->rq_reserved - space), &xprt->xpt_reserved);
530 rqstp->rq_reserved = space;
531 smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */
532 svc_xprt_enqueue(xprt);
533 }
534}
535EXPORT_SYMBOL_GPL(svc_reserve);
536
537static void svc_xprt_release(struct svc_rqst *rqstp)
538{
539 struct svc_xprt *xprt = rqstp->rq_xprt;
540
541 xprt->xpt_ops->xpo_release_rqst(rqstp);
542
543 kfree(rqstp->rq_deferred);
544 rqstp->rq_deferred = NULL;
545
546 pagevec_release(&rqstp->rq_pvec);
547 svc_free_res_pages(rqstp);
548 rqstp->rq_res.page_len = 0;
549 rqstp->rq_res.page_base = 0;
550
551 /* Reset response buffer and release
552 * the reservation.
553 * But first, check that enough space was reserved
554 * for the reply, otherwise we have a bug!
555 */
556 if ((rqstp->rq_res.len) > rqstp->rq_reserved)
557 printk(KERN_ERR "RPC request reserved %d but used %d\n",
558 rqstp->rq_reserved,
559 rqstp->rq_res.len);
560
561 rqstp->rq_res.head[0].iov_len = 0;
562 svc_reserve(rqstp, 0);
563 svc_xprt_release_slot(rqstp);
564 rqstp->rq_xprt = NULL;
565 svc_xprt_put(xprt);
566}
567
568/*
569 * Some svc_serv's will have occasional work to do, even when a xprt is not
570 * waiting to be serviced. This function is there to "kick" a task in one of
571 * those services so that it can wake up and do that work. Note that we only
572 * bother with pool 0 as we don't need to wake up more than one thread for
573 * this purpose.
574 */
575void svc_wake_up(struct svc_serv *serv)
576{
577 struct svc_rqst *rqstp;
578 struct svc_pool *pool;
579
580 pool = &serv->sv_pools[0];
581
582 rcu_read_lock();
583 list_for_each_entry_rcu(rqstp, &pool->sp_all_threads, rq_all) {
584 /* skip any that aren't queued */
585 if (test_bit(RQ_BUSY, &rqstp->rq_flags))
586 continue;
587 rcu_read_unlock();
588 wake_up_process(rqstp->rq_task);
589 trace_svc_wake_up(rqstp->rq_task->pid);
590 return;
591 }
592 rcu_read_unlock();
593
594 /* No free entries available */
595 set_bit(SP_TASK_PENDING, &pool->sp_flags);
596 smp_wmb();
597 trace_svc_wake_up(0);
598}
599EXPORT_SYMBOL_GPL(svc_wake_up);
600
601int svc_port_is_privileged(struct sockaddr *sin)
602{
603 switch (sin->sa_family) {
604 case AF_INET:
605 return ntohs(((struct sockaddr_in *)sin)->sin_port)
606 < PROT_SOCK;
607 case AF_INET6:
608 return ntohs(((struct sockaddr_in6 *)sin)->sin6_port)
609 < PROT_SOCK;
610 default:
611 return 0;
612 }
613}
614
615/*
616 * Make sure that we don't have too many active connections. If we have,
617 * something must be dropped. It's not clear what will happen if we allow
618 * "too many" connections, but when dealing with network-facing software,
619 * we have to code defensively. Here we do that by imposing hard limits.
620 *
621 * There's no point in trying to do random drop here for DoS
622 * prevention. The NFS clients does 1 reconnect in 15 seconds. An
623 * attacker can easily beat that.
624 *
625 * The only somewhat efficient mechanism would be if drop old
626 * connections from the same IP first. But right now we don't even
627 * record the client IP in svc_sock.
628 *
629 * single-threaded services that expect a lot of clients will probably
630 * need to set sv_maxconn to override the default value which is based
631 * on the number of threads
632 */
633static void svc_check_conn_limits(struct svc_serv *serv)
634{
635 unsigned int limit = serv->sv_maxconn ? serv->sv_maxconn :
636 (serv->sv_nrthreads+3) * 20;
637
638 if (serv->sv_tmpcnt > limit) {
639 struct svc_xprt *xprt = NULL;
640 spin_lock_bh(&serv->sv_lock);
641 if (!list_empty(&serv->sv_tempsocks)) {
642 /* Try to help the admin */
643 net_notice_ratelimited("%s: too many open connections, consider increasing the %s\n",
644 serv->sv_name, serv->sv_maxconn ?
645 "max number of connections" :
646 "number of threads");
647 /*
648 * Always select the oldest connection. It's not fair,
649 * but so is life
650 */
651 xprt = list_entry(serv->sv_tempsocks.prev,
652 struct svc_xprt,
653 xpt_list);
654 set_bit(XPT_CLOSE, &xprt->xpt_flags);
655 svc_xprt_get(xprt);
656 }
657 spin_unlock_bh(&serv->sv_lock);
658
659 if (xprt) {
660 svc_xprt_enqueue(xprt);
661 svc_xprt_put(xprt);
662 }
663 }
664}
665
666static int svc_alloc_arg(struct svc_rqst *rqstp)
667{
668 struct svc_serv *serv = rqstp->rq_server;
669 struct xdr_buf *arg = &rqstp->rq_arg;
670 unsigned long pages, filled, ret;
671
672 pagevec_init(&rqstp->rq_pvec);
673
674 pages = (serv->sv_max_mesg + 2 * PAGE_SIZE) >> PAGE_SHIFT;
675 if (pages > RPCSVC_MAXPAGES) {
676 pr_warn_once("svc: warning: pages=%lu > RPCSVC_MAXPAGES=%lu\n",
677 pages, RPCSVC_MAXPAGES);
678 /* use as many pages as possible */
679 pages = RPCSVC_MAXPAGES;
680 }
681
682 for (filled = 0; filled < pages; filled = ret) {
683 ret = alloc_pages_bulk_array(GFP_KERNEL, pages,
684 rqstp->rq_pages);
685 if (ret > filled)
686 /* Made progress, don't sleep yet */
687 continue;
688
689 set_current_state(TASK_INTERRUPTIBLE);
690 if (signalled() || kthread_should_stop()) {
691 set_current_state(TASK_RUNNING);
692 return -EINTR;
693 }
694 trace_svc_alloc_arg_err(pages, ret);
695 memalloc_retry_wait(GFP_KERNEL);
696 }
697 rqstp->rq_page_end = &rqstp->rq_pages[pages];
698 rqstp->rq_pages[pages] = NULL; /* this might be seen in nfsd_splice_actor() */
699
700 /* Make arg->head point to first page and arg->pages point to rest */
701 arg->head[0].iov_base = page_address(rqstp->rq_pages[0]);
702 arg->head[0].iov_len = PAGE_SIZE;
703 arg->pages = rqstp->rq_pages + 1;
704 arg->page_base = 0;
705 /* save at least one page for response */
706 arg->page_len = (pages-2)*PAGE_SIZE;
707 arg->len = (pages-1)*PAGE_SIZE;
708 arg->tail[0].iov_len = 0;
709 return 0;
710}
711
712static bool
713rqst_should_sleep(struct svc_rqst *rqstp)
714{
715 struct svc_pool *pool = rqstp->rq_pool;
716
717 /* did someone call svc_wake_up? */
718 if (test_and_clear_bit(SP_TASK_PENDING, &pool->sp_flags))
719 return false;
720
721 /* was a socket queued? */
722 if (!list_empty(&pool->sp_sockets))
723 return false;
724
725 /* are we shutting down? */
726 if (signalled() || kthread_should_stop())
727 return false;
728
729 /* are we freezing? */
730 if (freezing(current))
731 return false;
732
733 return true;
734}
735
736static struct svc_xprt *svc_get_next_xprt(struct svc_rqst *rqstp, long timeout)
737{
738 struct svc_pool *pool = rqstp->rq_pool;
739 long time_left = 0;
740
741 /* rq_xprt should be clear on entry */
742 WARN_ON_ONCE(rqstp->rq_xprt);
743
744 rqstp->rq_xprt = svc_xprt_dequeue(pool);
745 if (rqstp->rq_xprt)
746 goto out_found;
747
748 /*
749 * We have to be able to interrupt this wait
750 * to bring down the daemons ...
751 */
752 set_current_state(TASK_INTERRUPTIBLE);
753 smp_mb__before_atomic();
754 clear_bit(SP_CONGESTED, &pool->sp_flags);
755 clear_bit(RQ_BUSY, &rqstp->rq_flags);
756 smp_mb__after_atomic();
757
758 if (likely(rqst_should_sleep(rqstp)))
759 time_left = schedule_timeout(timeout);
760 else
761 __set_current_state(TASK_RUNNING);
762
763 try_to_freeze();
764
765 set_bit(RQ_BUSY, &rqstp->rq_flags);
766 smp_mb__after_atomic();
767 rqstp->rq_xprt = svc_xprt_dequeue(pool);
768 if (rqstp->rq_xprt)
769 goto out_found;
770
771 if (!time_left)
772 atomic_long_inc(&pool->sp_stats.threads_timedout);
773
774 if (signalled() || kthread_should_stop())
775 return ERR_PTR(-EINTR);
776 return ERR_PTR(-EAGAIN);
777out_found:
778 /* Normally we will wait up to 5 seconds for any required
779 * cache information to be provided.
780 */
781 if (!test_bit(SP_CONGESTED, &pool->sp_flags))
782 rqstp->rq_chandle.thread_wait = 5*HZ;
783 else
784 rqstp->rq_chandle.thread_wait = 1*HZ;
785 trace_svc_xprt_dequeue(rqstp);
786 return rqstp->rq_xprt;
787}
788
789static void svc_add_new_temp_xprt(struct svc_serv *serv, struct svc_xprt *newxpt)
790{
791 spin_lock_bh(&serv->sv_lock);
792 set_bit(XPT_TEMP, &newxpt->xpt_flags);
793 list_add(&newxpt->xpt_list, &serv->sv_tempsocks);
794 serv->sv_tmpcnt++;
795 if (serv->sv_temptimer.function == NULL) {
796 /* setup timer to age temp transports */
797 serv->sv_temptimer.function = svc_age_temp_xprts;
798 mod_timer(&serv->sv_temptimer,
799 jiffies + svc_conn_age_period * HZ);
800 }
801 spin_unlock_bh(&serv->sv_lock);
802 svc_xprt_received(newxpt);
803}
804
805static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
806{
807 struct svc_serv *serv = rqstp->rq_server;
808 int len = 0;
809
810 if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) {
811 if (test_and_clear_bit(XPT_KILL_TEMP, &xprt->xpt_flags))
812 xprt->xpt_ops->xpo_kill_temp_xprt(xprt);
813 svc_delete_xprt(xprt);
814 /* Leave XPT_BUSY set on the dead xprt: */
815 goto out;
816 }
817 if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) {
818 struct svc_xprt *newxpt;
819 /*
820 * We know this module_get will succeed because the
821 * listener holds a reference too
822 */
823 __module_get(xprt->xpt_class->xcl_owner);
824 svc_check_conn_limits(xprt->xpt_server);
825 newxpt = xprt->xpt_ops->xpo_accept(xprt);
826 if (newxpt) {
827 newxpt->xpt_cred = get_cred(xprt->xpt_cred);
828 svc_add_new_temp_xprt(serv, newxpt);
829 trace_svc_xprt_accept(newxpt, serv->sv_name);
830 } else {
831 module_put(xprt->xpt_class->xcl_owner);
832 }
833 svc_xprt_received(xprt);
834 } else if (svc_xprt_reserve_slot(rqstp, xprt)) {
835 /* XPT_DATA|XPT_DEFERRED case: */
836 dprintk("svc: server %p, pool %u, transport %p, inuse=%d\n",
837 rqstp, rqstp->rq_pool->sp_id, xprt,
838 kref_read(&xprt->xpt_ref));
839 rqstp->rq_deferred = svc_deferred_dequeue(xprt);
840 if (rqstp->rq_deferred)
841 len = svc_deferred_recv(rqstp);
842 else
843 len = xprt->xpt_ops->xpo_recvfrom(rqstp);
844 rqstp->rq_stime = ktime_get();
845 rqstp->rq_reserved = serv->sv_max_mesg;
846 atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
847 } else
848 svc_xprt_received(xprt);
849
850out:
851 return len;
852}
853
854/*
855 * Receive the next request on any transport. This code is carefully
856 * organised not to touch any cachelines in the shared svc_serv
857 * structure, only cachelines in the local svc_pool.
858 */
859int svc_recv(struct svc_rqst *rqstp, long timeout)
860{
861 struct svc_xprt *xprt = NULL;
862 struct svc_serv *serv = rqstp->rq_server;
863 int len, err;
864
865 err = svc_alloc_arg(rqstp);
866 if (err)
867 goto out;
868
869 try_to_freeze();
870 cond_resched();
871 err = -EINTR;
872 if (signalled() || kthread_should_stop())
873 goto out;
874
875 xprt = svc_get_next_xprt(rqstp, timeout);
876 if (IS_ERR(xprt)) {
877 err = PTR_ERR(xprt);
878 goto out;
879 }
880
881 len = svc_handle_xprt(rqstp, xprt);
882
883 /* No data, incomplete (TCP) read, or accept() */
884 err = -EAGAIN;
885 if (len <= 0)
886 goto out_release;
887 trace_svc_xdr_recvfrom(&rqstp->rq_arg);
888
889 clear_bit(XPT_OLD, &xprt->xpt_flags);
890
891 xprt->xpt_ops->xpo_secure_port(rqstp);
892 rqstp->rq_chandle.defer = svc_defer;
893 rqstp->rq_xid = svc_getu32(&rqstp->rq_arg.head[0]);
894
895 if (serv->sv_stats)
896 serv->sv_stats->netcnt++;
897 return len;
898out_release:
899 rqstp->rq_res.len = 0;
900 svc_xprt_release(rqstp);
901out:
902 return err;
903}
904EXPORT_SYMBOL_GPL(svc_recv);
905
906/*
907 * Drop request
908 */
909void svc_drop(struct svc_rqst *rqstp)
910{
911 trace_svc_drop(rqstp);
912 svc_xprt_release(rqstp);
913}
914EXPORT_SYMBOL_GPL(svc_drop);
915
916/*
917 * Return reply to client.
918 */
919int svc_send(struct svc_rqst *rqstp)
920{
921 struct svc_xprt *xprt;
922 int len = -EFAULT;
923 struct xdr_buf *xb;
924
925 xprt = rqstp->rq_xprt;
926 if (!xprt)
927 goto out;
928
929 /* calculate over-all length */
930 xb = &rqstp->rq_res;
931 xb->len = xb->head[0].iov_len +
932 xb->page_len +
933 xb->tail[0].iov_len;
934 trace_svc_xdr_sendto(rqstp->rq_xid, xb);
935 trace_svc_stats_latency(rqstp);
936
937 len = xprt->xpt_ops->xpo_sendto(rqstp);
938
939 trace_svc_send(rqstp, len);
940 svc_xprt_release(rqstp);
941
942 if (len == -ECONNREFUSED || len == -ENOTCONN || len == -EAGAIN)
943 len = 0;
944out:
945 return len;
946}
947
948/*
949 * Timer function to close old temporary transports, using
950 * a mark-and-sweep algorithm.
951 */
952static void svc_age_temp_xprts(struct timer_list *t)
953{
954 struct svc_serv *serv = from_timer(serv, t, sv_temptimer);
955 struct svc_xprt *xprt;
956 struct list_head *le, *next;
957
958 dprintk("svc_age_temp_xprts\n");
959
960 if (!spin_trylock_bh(&serv->sv_lock)) {
961 /* busy, try again 1 sec later */
962 dprintk("svc_age_temp_xprts: busy\n");
963 mod_timer(&serv->sv_temptimer, jiffies + HZ);
964 return;
965 }
966
967 list_for_each_safe(le, next, &serv->sv_tempsocks) {
968 xprt = list_entry(le, struct svc_xprt, xpt_list);
969
970 /* First time through, just mark it OLD. Second time
971 * through, close it. */
972 if (!test_and_set_bit(XPT_OLD, &xprt->xpt_flags))
973 continue;
974 if (kref_read(&xprt->xpt_ref) > 1 ||
975 test_bit(XPT_BUSY, &xprt->xpt_flags))
976 continue;
977 list_del_init(le);
978 set_bit(XPT_CLOSE, &xprt->xpt_flags);
979 dprintk("queuing xprt %p for closing\n", xprt);
980
981 /* a thread will dequeue and close it soon */
982 svc_xprt_enqueue(xprt);
983 }
984 spin_unlock_bh(&serv->sv_lock);
985
986 mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ);
987}
988
989/* Close temporary transports whose xpt_local matches server_addr immediately
990 * instead of waiting for them to be picked up by the timer.
991 *
992 * This is meant to be called from a notifier_block that runs when an ip
993 * address is deleted.
994 */
995void svc_age_temp_xprts_now(struct svc_serv *serv, struct sockaddr *server_addr)
996{
997 struct svc_xprt *xprt;
998 struct list_head *le, *next;
999 LIST_HEAD(to_be_closed);
1000
1001 spin_lock_bh(&serv->sv_lock);
1002 list_for_each_safe(le, next, &serv->sv_tempsocks) {
1003 xprt = list_entry(le, struct svc_xprt, xpt_list);
1004 if (rpc_cmp_addr(server_addr, (struct sockaddr *)
1005 &xprt->xpt_local)) {
1006 dprintk("svc_age_temp_xprts_now: found %p\n", xprt);
1007 list_move(le, &to_be_closed);
1008 }
1009 }
1010 spin_unlock_bh(&serv->sv_lock);
1011
1012 while (!list_empty(&to_be_closed)) {
1013 le = to_be_closed.next;
1014 list_del_init(le);
1015 xprt = list_entry(le, struct svc_xprt, xpt_list);
1016 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1017 set_bit(XPT_KILL_TEMP, &xprt->xpt_flags);
1018 dprintk("svc_age_temp_xprts_now: queuing xprt %p for closing\n",
1019 xprt);
1020 svc_xprt_enqueue(xprt);
1021 }
1022}
1023EXPORT_SYMBOL_GPL(svc_age_temp_xprts_now);
1024
1025static void call_xpt_users(struct svc_xprt *xprt)
1026{
1027 struct svc_xpt_user *u;
1028
1029 spin_lock(&xprt->xpt_lock);
1030 while (!list_empty(&xprt->xpt_users)) {
1031 u = list_first_entry(&xprt->xpt_users, struct svc_xpt_user, list);
1032 list_del_init(&u->list);
1033 u->callback(u);
1034 }
1035 spin_unlock(&xprt->xpt_lock);
1036}
1037
1038/*
1039 * Remove a dead transport
1040 */
1041static void svc_delete_xprt(struct svc_xprt *xprt)
1042{
1043 struct svc_serv *serv = xprt->xpt_server;
1044 struct svc_deferred_req *dr;
1045
1046 if (test_and_set_bit(XPT_DEAD, &xprt->xpt_flags))
1047 return;
1048
1049 trace_svc_xprt_detach(xprt);
1050 xprt->xpt_ops->xpo_detach(xprt);
1051 if (xprt->xpt_bc_xprt)
1052 xprt->xpt_bc_xprt->ops->close(xprt->xpt_bc_xprt);
1053
1054 spin_lock_bh(&serv->sv_lock);
1055 list_del_init(&xprt->xpt_list);
1056 WARN_ON_ONCE(!list_empty(&xprt->xpt_ready));
1057 if (test_bit(XPT_TEMP, &xprt->xpt_flags))
1058 serv->sv_tmpcnt--;
1059 spin_unlock_bh(&serv->sv_lock);
1060
1061 while ((dr = svc_deferred_dequeue(xprt)) != NULL)
1062 kfree(dr);
1063
1064 call_xpt_users(xprt);
1065 svc_xprt_put(xprt);
1066}
1067
1068/**
1069 * svc_xprt_close - Close a client connection
1070 * @xprt: transport to disconnect
1071 *
1072 */
1073void svc_xprt_close(struct svc_xprt *xprt)
1074{
1075 trace_svc_xprt_close(xprt);
1076 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1077 if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
1078 /* someone else will have to effect the close */
1079 return;
1080 /*
1081 * We expect svc_close_xprt() to work even when no threads are
1082 * running (e.g., while configuring the server before starting
1083 * any threads), so if the transport isn't busy, we delete
1084 * it ourself:
1085 */
1086 svc_delete_xprt(xprt);
1087}
1088EXPORT_SYMBOL_GPL(svc_xprt_close);
1089
1090static int svc_close_list(struct svc_serv *serv, struct list_head *xprt_list, struct net *net)
1091{
1092 struct svc_xprt *xprt;
1093 int ret = 0;
1094
1095 spin_lock_bh(&serv->sv_lock);
1096 list_for_each_entry(xprt, xprt_list, xpt_list) {
1097 if (xprt->xpt_net != net)
1098 continue;
1099 ret++;
1100 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1101 svc_xprt_enqueue(xprt);
1102 }
1103 spin_unlock_bh(&serv->sv_lock);
1104 return ret;
1105}
1106
1107static struct svc_xprt *svc_dequeue_net(struct svc_serv *serv, struct net *net)
1108{
1109 struct svc_pool *pool;
1110 struct svc_xprt *xprt;
1111 struct svc_xprt *tmp;
1112 int i;
1113
1114 for (i = 0; i < serv->sv_nrpools; i++) {
1115 pool = &serv->sv_pools[i];
1116
1117 spin_lock_bh(&pool->sp_lock);
1118 list_for_each_entry_safe(xprt, tmp, &pool->sp_sockets, xpt_ready) {
1119 if (xprt->xpt_net != net)
1120 continue;
1121 list_del_init(&xprt->xpt_ready);
1122 spin_unlock_bh(&pool->sp_lock);
1123 return xprt;
1124 }
1125 spin_unlock_bh(&pool->sp_lock);
1126 }
1127 return NULL;
1128}
1129
1130static void svc_clean_up_xprts(struct svc_serv *serv, struct net *net)
1131{
1132 struct svc_xprt *xprt;
1133
1134 while ((xprt = svc_dequeue_net(serv, net))) {
1135 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1136 svc_delete_xprt(xprt);
1137 }
1138}
1139
1140/**
1141 * svc_xprt_destroy_all - Destroy transports associated with @serv
1142 * @serv: RPC service to be shut down
1143 * @net: target network namespace
1144 *
1145 * Server threads may still be running (especially in the case where the
1146 * service is still running in other network namespaces).
1147 *
1148 * So we shut down sockets the same way we would on a running server, by
1149 * setting XPT_CLOSE, enqueuing, and letting a thread pick it up to do
1150 * the close. In the case there are no such other threads,
1151 * threads running, svc_clean_up_xprts() does a simple version of a
1152 * server's main event loop, and in the case where there are other
1153 * threads, we may need to wait a little while and then check again to
1154 * see if they're done.
1155 */
1156void svc_xprt_destroy_all(struct svc_serv *serv, struct net *net)
1157{
1158 int delay = 0;
1159
1160 while (svc_close_list(serv, &serv->sv_permsocks, net) +
1161 svc_close_list(serv, &serv->sv_tempsocks, net)) {
1162
1163 svc_clean_up_xprts(serv, net);
1164 msleep(delay++);
1165 }
1166}
1167EXPORT_SYMBOL_GPL(svc_xprt_destroy_all);
1168
1169/*
1170 * Handle defer and revisit of requests
1171 */
1172
1173static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
1174{
1175 struct svc_deferred_req *dr =
1176 container_of(dreq, struct svc_deferred_req, handle);
1177 struct svc_xprt *xprt = dr->xprt;
1178
1179 spin_lock(&xprt->xpt_lock);
1180 set_bit(XPT_DEFERRED, &xprt->xpt_flags);
1181 if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) {
1182 spin_unlock(&xprt->xpt_lock);
1183 trace_svc_defer_drop(dr);
1184 svc_xprt_put(xprt);
1185 kfree(dr);
1186 return;
1187 }
1188 dr->xprt = NULL;
1189 list_add(&dr->handle.recent, &xprt->xpt_deferred);
1190 spin_unlock(&xprt->xpt_lock);
1191 trace_svc_defer_queue(dr);
1192 svc_xprt_enqueue(xprt);
1193 svc_xprt_put(xprt);
1194}
1195
1196/*
1197 * Save the request off for later processing. The request buffer looks
1198 * like this:
1199 *
1200 * <xprt-header><rpc-header><rpc-pagelist><rpc-tail>
1201 *
1202 * This code can only handle requests that consist of an xprt-header
1203 * and rpc-header.
1204 */
1205static struct cache_deferred_req *svc_defer(struct cache_req *req)
1206{
1207 struct svc_rqst *rqstp = container_of(req, struct svc_rqst, rq_chandle);
1208 struct svc_deferred_req *dr;
1209
1210 if (rqstp->rq_arg.page_len || !test_bit(RQ_USEDEFERRAL, &rqstp->rq_flags))
1211 return NULL; /* if more than a page, give up FIXME */
1212 if (rqstp->rq_deferred) {
1213 dr = rqstp->rq_deferred;
1214 rqstp->rq_deferred = NULL;
1215 } else {
1216 size_t skip;
1217 size_t size;
1218 /* FIXME maybe discard if size too large */
1219 size = sizeof(struct svc_deferred_req) + rqstp->rq_arg.len;
1220 dr = kmalloc(size, GFP_KERNEL);
1221 if (dr == NULL)
1222 return NULL;
1223
1224 dr->handle.owner = rqstp->rq_server;
1225 dr->prot = rqstp->rq_prot;
1226 memcpy(&dr->addr, &rqstp->rq_addr, rqstp->rq_addrlen);
1227 dr->addrlen = rqstp->rq_addrlen;
1228 dr->daddr = rqstp->rq_daddr;
1229 dr->argslen = rqstp->rq_arg.len >> 2;
1230 dr->xprt_ctxt = rqstp->rq_xprt_ctxt;
1231 rqstp->rq_xprt_ctxt = NULL;
1232
1233 /* back up head to the start of the buffer and copy */
1234 skip = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len;
1235 memcpy(dr->args, rqstp->rq_arg.head[0].iov_base - skip,
1236 dr->argslen << 2);
1237 }
1238 trace_svc_defer(rqstp);
1239 svc_xprt_get(rqstp->rq_xprt);
1240 dr->xprt = rqstp->rq_xprt;
1241 set_bit(RQ_DROPME, &rqstp->rq_flags);
1242
1243 dr->handle.revisit = svc_revisit;
1244 return &dr->handle;
1245}
1246
1247/*
1248 * recv data from a deferred request into an active one
1249 */
1250static noinline int svc_deferred_recv(struct svc_rqst *rqstp)
1251{
1252 struct svc_deferred_req *dr = rqstp->rq_deferred;
1253
1254 trace_svc_defer_recv(dr);
1255
1256 /* setup iov_base past transport header */
1257 rqstp->rq_arg.head[0].iov_base = dr->args;
1258 /* The iov_len does not include the transport header bytes */
1259 rqstp->rq_arg.head[0].iov_len = dr->argslen << 2;
1260 rqstp->rq_arg.page_len = 0;
1261 /* The rq_arg.len includes the transport header bytes */
1262 rqstp->rq_arg.len = dr->argslen << 2;
1263 rqstp->rq_prot = dr->prot;
1264 memcpy(&rqstp->rq_addr, &dr->addr, dr->addrlen);
1265 rqstp->rq_addrlen = dr->addrlen;
1266 /* Save off transport header len in case we get deferred again */
1267 rqstp->rq_daddr = dr->daddr;
1268 rqstp->rq_respages = rqstp->rq_pages;
1269 rqstp->rq_xprt_ctxt = dr->xprt_ctxt;
1270 svc_xprt_received(rqstp->rq_xprt);
1271 return dr->argslen << 2;
1272}
1273
1274
1275static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt)
1276{
1277 struct svc_deferred_req *dr = NULL;
1278
1279 if (!test_bit(XPT_DEFERRED, &xprt->xpt_flags))
1280 return NULL;
1281 spin_lock(&xprt->xpt_lock);
1282 if (!list_empty(&xprt->xpt_deferred)) {
1283 dr = list_entry(xprt->xpt_deferred.next,
1284 struct svc_deferred_req,
1285 handle.recent);
1286 list_del_init(&dr->handle.recent);
1287 } else
1288 clear_bit(XPT_DEFERRED, &xprt->xpt_flags);
1289 spin_unlock(&xprt->xpt_lock);
1290 return dr;
1291}
1292
1293/**
1294 * svc_find_xprt - find an RPC transport instance
1295 * @serv: pointer to svc_serv to search
1296 * @xcl_name: C string containing transport's class name
1297 * @net: owner net pointer
1298 * @af: Address family of transport's local address
1299 * @port: transport's IP port number
1300 *
1301 * Return the transport instance pointer for the endpoint accepting
1302 * connections/peer traffic from the specified transport class,
1303 * address family and port.
1304 *
1305 * Specifying 0 for the address family or port is effectively a
1306 * wild-card, and will result in matching the first transport in the
1307 * service's list that has a matching class name.
1308 */
1309struct svc_xprt *svc_find_xprt(struct svc_serv *serv, const char *xcl_name,
1310 struct net *net, const sa_family_t af,
1311 const unsigned short port)
1312{
1313 struct svc_xprt *xprt;
1314 struct svc_xprt *found = NULL;
1315
1316 /* Sanity check the args */
1317 if (serv == NULL || xcl_name == NULL)
1318 return found;
1319
1320 spin_lock_bh(&serv->sv_lock);
1321 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1322 if (xprt->xpt_net != net)
1323 continue;
1324 if (strcmp(xprt->xpt_class->xcl_name, xcl_name))
1325 continue;
1326 if (af != AF_UNSPEC && af != xprt->xpt_local.ss_family)
1327 continue;
1328 if (port != 0 && port != svc_xprt_local_port(xprt))
1329 continue;
1330 found = xprt;
1331 svc_xprt_get(xprt);
1332 break;
1333 }
1334 spin_unlock_bh(&serv->sv_lock);
1335 return found;
1336}
1337EXPORT_SYMBOL_GPL(svc_find_xprt);
1338
1339static int svc_one_xprt_name(const struct svc_xprt *xprt,
1340 char *pos, int remaining)
1341{
1342 int len;
1343
1344 len = snprintf(pos, remaining, "%s %u\n",
1345 xprt->xpt_class->xcl_name,
1346 svc_xprt_local_port(xprt));
1347 if (len >= remaining)
1348 return -ENAMETOOLONG;
1349 return len;
1350}
1351
1352/**
1353 * svc_xprt_names - format a buffer with a list of transport names
1354 * @serv: pointer to an RPC service
1355 * @buf: pointer to a buffer to be filled in
1356 * @buflen: length of buffer to be filled in
1357 *
1358 * Fills in @buf with a string containing a list of transport names,
1359 * each name terminated with '\n'.
1360 *
1361 * Returns positive length of the filled-in string on success; otherwise
1362 * a negative errno value is returned if an error occurs.
1363 */
1364int svc_xprt_names(struct svc_serv *serv, char *buf, const int buflen)
1365{
1366 struct svc_xprt *xprt;
1367 int len, totlen;
1368 char *pos;
1369
1370 /* Sanity check args */
1371 if (!serv)
1372 return 0;
1373
1374 spin_lock_bh(&serv->sv_lock);
1375
1376 pos = buf;
1377 totlen = 0;
1378 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1379 len = svc_one_xprt_name(xprt, pos, buflen - totlen);
1380 if (len < 0) {
1381 *buf = '\0';
1382 totlen = len;
1383 }
1384 if (len <= 0)
1385 break;
1386
1387 pos += len;
1388 totlen += len;
1389 }
1390
1391 spin_unlock_bh(&serv->sv_lock);
1392 return totlen;
1393}
1394EXPORT_SYMBOL_GPL(svc_xprt_names);
1395
1396
1397/*----------------------------------------------------------------------------*/
1398
1399static void *svc_pool_stats_start(struct seq_file *m, loff_t *pos)
1400{
1401 unsigned int pidx = (unsigned int)*pos;
1402 struct svc_serv *serv = m->private;
1403
1404 dprintk("svc_pool_stats_start, *pidx=%u\n", pidx);
1405
1406 if (!pidx)
1407 return SEQ_START_TOKEN;
1408 return (pidx > serv->sv_nrpools ? NULL : &serv->sv_pools[pidx-1]);
1409}
1410
1411static void *svc_pool_stats_next(struct seq_file *m, void *p, loff_t *pos)
1412{
1413 struct svc_pool *pool = p;
1414 struct svc_serv *serv = m->private;
1415
1416 dprintk("svc_pool_stats_next, *pos=%llu\n", *pos);
1417
1418 if (p == SEQ_START_TOKEN) {
1419 pool = &serv->sv_pools[0];
1420 } else {
1421 unsigned int pidx = (pool - &serv->sv_pools[0]);
1422 if (pidx < serv->sv_nrpools-1)
1423 pool = &serv->sv_pools[pidx+1];
1424 else
1425 pool = NULL;
1426 }
1427 ++*pos;
1428 return pool;
1429}
1430
1431static void svc_pool_stats_stop(struct seq_file *m, void *p)
1432{
1433}
1434
1435static int svc_pool_stats_show(struct seq_file *m, void *p)
1436{
1437 struct svc_pool *pool = p;
1438
1439 if (p == SEQ_START_TOKEN) {
1440 seq_puts(m, "# pool packets-arrived sockets-enqueued threads-woken threads-timedout\n");
1441 return 0;
1442 }
1443
1444 seq_printf(m, "%u %lu %lu %lu %lu\n",
1445 pool->sp_id,
1446 (unsigned long)atomic_long_read(&pool->sp_stats.packets),
1447 pool->sp_stats.sockets_queued,
1448 (unsigned long)atomic_long_read(&pool->sp_stats.threads_woken),
1449 (unsigned long)atomic_long_read(&pool->sp_stats.threads_timedout));
1450
1451 return 0;
1452}
1453
1454static const struct seq_operations svc_pool_stats_seq_ops = {
1455 .start = svc_pool_stats_start,
1456 .next = svc_pool_stats_next,
1457 .stop = svc_pool_stats_stop,
1458 .show = svc_pool_stats_show,
1459};
1460
1461int svc_pool_stats_open(struct svc_serv *serv, struct file *file)
1462{
1463 int err;
1464
1465 err = seq_open(file, &svc_pool_stats_seq_ops);
1466 if (!err)
1467 ((struct seq_file *) file->private_data)->private = serv;
1468 return err;
1469}
1470EXPORT_SYMBOL(svc_pool_stats_open);
1471
1472/*----------------------------------------------------------------------------*/
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 <linux/slab.h>
12#include <net/sock.h>
13#include <linux/sunrpc/stats.h>
14#include <linux/sunrpc/svc_xprt.h>
15#include <linux/sunrpc/svcsock.h>
16#include <linux/sunrpc/xprt.h>
17
18#define RPCDBG_FACILITY RPCDBG_SVCXPRT
19
20static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt);
21static int svc_deferred_recv(struct svc_rqst *rqstp);
22static struct cache_deferred_req *svc_defer(struct cache_req *req);
23static void svc_age_temp_xprts(unsigned long closure);
24
25/* apparently the "standard" is that clients close
26 * idle connections after 5 minutes, servers after
27 * 6 minutes
28 * http://www.connectathon.org/talks96/nfstcp.pdf
29 */
30static int svc_conn_age_period = 6*60;
31
32/* List of registered transport classes */
33static DEFINE_SPINLOCK(svc_xprt_class_lock);
34static LIST_HEAD(svc_xprt_class_list);
35
36/* SMP locking strategy:
37 *
38 * svc_pool->sp_lock protects most of the fields of that pool.
39 * svc_serv->sv_lock protects sv_tempsocks, sv_permsocks, sv_tmpcnt.
40 * when both need to be taken (rare), svc_serv->sv_lock is first.
41 * BKL protects svc_serv->sv_nrthread.
42 * svc_sock->sk_lock protects the svc_sock->sk_deferred list
43 * and the ->sk_info_authunix cache.
44 *
45 * The XPT_BUSY bit in xprt->xpt_flags prevents a transport being
46 * enqueued multiply. During normal transport processing this bit
47 * is set by svc_xprt_enqueue and cleared by svc_xprt_received.
48 * Providers should not manipulate this bit directly.
49 *
50 * Some flags can be set to certain values at any time
51 * providing that certain rules are followed:
52 *
53 * XPT_CONN, XPT_DATA:
54 * - Can be set or cleared at any time.
55 * - After a set, svc_xprt_enqueue must be called to enqueue
56 * the transport for processing.
57 * - After a clear, the transport must be read/accepted.
58 * If this succeeds, it must be set again.
59 * XPT_CLOSE:
60 * - Can set at any time. It is never cleared.
61 * XPT_DEAD:
62 * - Can only be set while XPT_BUSY is held which ensures
63 * that no other thread will be using the transport or will
64 * try to set XPT_DEAD.
65 */
66
67int svc_reg_xprt_class(struct svc_xprt_class *xcl)
68{
69 struct svc_xprt_class *cl;
70 int res = -EEXIST;
71
72 dprintk("svc: Adding svc transport class '%s'\n", xcl->xcl_name);
73
74 INIT_LIST_HEAD(&xcl->xcl_list);
75 spin_lock(&svc_xprt_class_lock);
76 /* Make sure there isn't already a class with the same name */
77 list_for_each_entry(cl, &svc_xprt_class_list, xcl_list) {
78 if (strcmp(xcl->xcl_name, cl->xcl_name) == 0)
79 goto out;
80 }
81 list_add_tail(&xcl->xcl_list, &svc_xprt_class_list);
82 res = 0;
83out:
84 spin_unlock(&svc_xprt_class_lock);
85 return res;
86}
87EXPORT_SYMBOL_GPL(svc_reg_xprt_class);
88
89void svc_unreg_xprt_class(struct svc_xprt_class *xcl)
90{
91 dprintk("svc: Removing svc transport class '%s'\n", xcl->xcl_name);
92 spin_lock(&svc_xprt_class_lock);
93 list_del_init(&xcl->xcl_list);
94 spin_unlock(&svc_xprt_class_lock);
95}
96EXPORT_SYMBOL_GPL(svc_unreg_xprt_class);
97
98/*
99 * Format the transport list for printing
100 */
101int svc_print_xprts(char *buf, int maxlen)
102{
103 struct svc_xprt_class *xcl;
104 char tmpstr[80];
105 int len = 0;
106 buf[0] = '\0';
107
108 spin_lock(&svc_xprt_class_lock);
109 list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
110 int slen;
111
112 sprintf(tmpstr, "%s %d\n", xcl->xcl_name, xcl->xcl_max_payload);
113 slen = strlen(tmpstr);
114 if (len + slen > maxlen)
115 break;
116 len += slen;
117 strcat(buf, tmpstr);
118 }
119 spin_unlock(&svc_xprt_class_lock);
120
121 return len;
122}
123
124static void svc_xprt_free(struct kref *kref)
125{
126 struct svc_xprt *xprt =
127 container_of(kref, struct svc_xprt, xpt_ref);
128 struct module *owner = xprt->xpt_class->xcl_owner;
129 if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags))
130 svcauth_unix_info_release(xprt);
131 put_net(xprt->xpt_net);
132 /* See comment on corresponding get in xs_setup_bc_tcp(): */
133 if (xprt->xpt_bc_xprt)
134 xprt_put(xprt->xpt_bc_xprt);
135 xprt->xpt_ops->xpo_free(xprt);
136 module_put(owner);
137}
138
139void svc_xprt_put(struct svc_xprt *xprt)
140{
141 kref_put(&xprt->xpt_ref, svc_xprt_free);
142}
143EXPORT_SYMBOL_GPL(svc_xprt_put);
144
145/*
146 * Called by transport drivers to initialize the transport independent
147 * portion of the transport instance.
148 */
149void svc_xprt_init(struct svc_xprt_class *xcl, struct svc_xprt *xprt,
150 struct svc_serv *serv)
151{
152 memset(xprt, 0, sizeof(*xprt));
153 xprt->xpt_class = xcl;
154 xprt->xpt_ops = xcl->xcl_ops;
155 kref_init(&xprt->xpt_ref);
156 xprt->xpt_server = serv;
157 INIT_LIST_HEAD(&xprt->xpt_list);
158 INIT_LIST_HEAD(&xprt->xpt_ready);
159 INIT_LIST_HEAD(&xprt->xpt_deferred);
160 INIT_LIST_HEAD(&xprt->xpt_users);
161 mutex_init(&xprt->xpt_mutex);
162 spin_lock_init(&xprt->xpt_lock);
163 set_bit(XPT_BUSY, &xprt->xpt_flags);
164 rpc_init_wait_queue(&xprt->xpt_bc_pending, "xpt_bc_pending");
165 xprt->xpt_net = get_net(&init_net);
166}
167EXPORT_SYMBOL_GPL(svc_xprt_init);
168
169static struct svc_xprt *__svc_xpo_create(struct svc_xprt_class *xcl,
170 struct svc_serv *serv,
171 struct net *net,
172 const int family,
173 const unsigned short port,
174 int flags)
175{
176 struct sockaddr_in sin = {
177 .sin_family = AF_INET,
178 .sin_addr.s_addr = htonl(INADDR_ANY),
179 .sin_port = htons(port),
180 };
181#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
182 struct sockaddr_in6 sin6 = {
183 .sin6_family = AF_INET6,
184 .sin6_addr = IN6ADDR_ANY_INIT,
185 .sin6_port = htons(port),
186 };
187#endif /* defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) */
188 struct sockaddr *sap;
189 size_t len;
190
191 switch (family) {
192 case PF_INET:
193 sap = (struct sockaddr *)&sin;
194 len = sizeof(sin);
195 break;
196#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
197 case PF_INET6:
198 sap = (struct sockaddr *)&sin6;
199 len = sizeof(sin6);
200 break;
201#endif /* defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) */
202 default:
203 return ERR_PTR(-EAFNOSUPPORT);
204 }
205
206 return xcl->xcl_ops->xpo_create(serv, net, sap, len, flags);
207}
208
209int svc_create_xprt(struct svc_serv *serv, const char *xprt_name,
210 struct net *net, const int family,
211 const unsigned short port, int flags)
212{
213 struct svc_xprt_class *xcl;
214
215 dprintk("svc: creating transport %s[%d]\n", xprt_name, port);
216 spin_lock(&svc_xprt_class_lock);
217 list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
218 struct svc_xprt *newxprt;
219 unsigned short newport;
220
221 if (strcmp(xprt_name, xcl->xcl_name))
222 continue;
223
224 if (!try_module_get(xcl->xcl_owner))
225 goto err;
226
227 spin_unlock(&svc_xprt_class_lock);
228 newxprt = __svc_xpo_create(xcl, serv, net, family, port, flags);
229 if (IS_ERR(newxprt)) {
230 module_put(xcl->xcl_owner);
231 return PTR_ERR(newxprt);
232 }
233
234 clear_bit(XPT_TEMP, &newxprt->xpt_flags);
235 spin_lock_bh(&serv->sv_lock);
236 list_add(&newxprt->xpt_list, &serv->sv_permsocks);
237 spin_unlock_bh(&serv->sv_lock);
238 newport = svc_xprt_local_port(newxprt);
239 clear_bit(XPT_BUSY, &newxprt->xpt_flags);
240 return newport;
241 }
242 err:
243 spin_unlock(&svc_xprt_class_lock);
244 dprintk("svc: transport %s not found\n", xprt_name);
245
246 /* This errno is exposed to user space. Provide a reasonable
247 * perror msg for a bad transport. */
248 return -EPROTONOSUPPORT;
249}
250EXPORT_SYMBOL_GPL(svc_create_xprt);
251
252/*
253 * Copy the local and remote xprt addresses to the rqstp structure
254 */
255void svc_xprt_copy_addrs(struct svc_rqst *rqstp, struct svc_xprt *xprt)
256{
257 struct sockaddr *sin;
258
259 memcpy(&rqstp->rq_addr, &xprt->xpt_remote, xprt->xpt_remotelen);
260 rqstp->rq_addrlen = xprt->xpt_remotelen;
261
262 /*
263 * Destination address in request is needed for binding the
264 * source address in RPC replies/callbacks later.
265 */
266 sin = (struct sockaddr *)&xprt->xpt_local;
267 switch (sin->sa_family) {
268 case AF_INET:
269 rqstp->rq_daddr.addr = ((struct sockaddr_in *)sin)->sin_addr;
270 break;
271 case AF_INET6:
272 rqstp->rq_daddr.addr6 = ((struct sockaddr_in6 *)sin)->sin6_addr;
273 break;
274 }
275}
276EXPORT_SYMBOL_GPL(svc_xprt_copy_addrs);
277
278/**
279 * svc_print_addr - Format rq_addr field for printing
280 * @rqstp: svc_rqst struct containing address to print
281 * @buf: target buffer for formatted address
282 * @len: length of target buffer
283 *
284 */
285char *svc_print_addr(struct svc_rqst *rqstp, char *buf, size_t len)
286{
287 return __svc_print_addr(svc_addr(rqstp), buf, len);
288}
289EXPORT_SYMBOL_GPL(svc_print_addr);
290
291/*
292 * Queue up an idle server thread. Must have pool->sp_lock held.
293 * Note: this is really a stack rather than a queue, so that we only
294 * use as many different threads as we need, and the rest don't pollute
295 * the cache.
296 */
297static void svc_thread_enqueue(struct svc_pool *pool, struct svc_rqst *rqstp)
298{
299 list_add(&rqstp->rq_list, &pool->sp_threads);
300}
301
302/*
303 * Dequeue an nfsd thread. Must have pool->sp_lock held.
304 */
305static void svc_thread_dequeue(struct svc_pool *pool, struct svc_rqst *rqstp)
306{
307 list_del(&rqstp->rq_list);
308}
309
310static bool svc_xprt_has_something_to_do(struct svc_xprt *xprt)
311{
312 if (xprt->xpt_flags & ((1<<XPT_CONN)|(1<<XPT_CLOSE)))
313 return true;
314 if (xprt->xpt_flags & ((1<<XPT_DATA)|(1<<XPT_DEFERRED)))
315 return xprt->xpt_ops->xpo_has_wspace(xprt);
316 return false;
317}
318
319/*
320 * Queue up a transport with data pending. If there are idle nfsd
321 * processes, wake 'em up.
322 *
323 */
324void svc_xprt_enqueue(struct svc_xprt *xprt)
325{
326 struct svc_serv *serv = xprt->xpt_server;
327 struct svc_pool *pool;
328 struct svc_rqst *rqstp;
329 int cpu;
330
331 if (!svc_xprt_has_something_to_do(xprt))
332 return;
333
334 cpu = get_cpu();
335 pool = svc_pool_for_cpu(xprt->xpt_server, cpu);
336 put_cpu();
337
338 spin_lock_bh(&pool->sp_lock);
339
340 if (!list_empty(&pool->sp_threads) &&
341 !list_empty(&pool->sp_sockets))
342 printk(KERN_ERR
343 "svc_xprt_enqueue: "
344 "threads and transports both waiting??\n");
345
346 pool->sp_stats.packets++;
347
348 /* Mark transport as busy. It will remain in this state until
349 * the provider calls svc_xprt_received. We update XPT_BUSY
350 * atomically because it also guards against trying to enqueue
351 * the transport twice.
352 */
353 if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags)) {
354 /* Don't enqueue transport while already enqueued */
355 dprintk("svc: transport %p busy, not enqueued\n", xprt);
356 goto out_unlock;
357 }
358
359 if (!list_empty(&pool->sp_threads)) {
360 rqstp = list_entry(pool->sp_threads.next,
361 struct svc_rqst,
362 rq_list);
363 dprintk("svc: transport %p served by daemon %p\n",
364 xprt, rqstp);
365 svc_thread_dequeue(pool, rqstp);
366 if (rqstp->rq_xprt)
367 printk(KERN_ERR
368 "svc_xprt_enqueue: server %p, rq_xprt=%p!\n",
369 rqstp, rqstp->rq_xprt);
370 rqstp->rq_xprt = xprt;
371 svc_xprt_get(xprt);
372 rqstp->rq_reserved = serv->sv_max_mesg;
373 atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
374 pool->sp_stats.threads_woken++;
375 wake_up(&rqstp->rq_wait);
376 } else {
377 dprintk("svc: transport %p put into queue\n", xprt);
378 list_add_tail(&xprt->xpt_ready, &pool->sp_sockets);
379 pool->sp_stats.sockets_queued++;
380 }
381
382out_unlock:
383 spin_unlock_bh(&pool->sp_lock);
384}
385EXPORT_SYMBOL_GPL(svc_xprt_enqueue);
386
387/*
388 * Dequeue the first transport. Must be called with the pool->sp_lock held.
389 */
390static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool)
391{
392 struct svc_xprt *xprt;
393
394 if (list_empty(&pool->sp_sockets))
395 return NULL;
396
397 xprt = list_entry(pool->sp_sockets.next,
398 struct svc_xprt, xpt_ready);
399 list_del_init(&xprt->xpt_ready);
400
401 dprintk("svc: transport %p dequeued, inuse=%d\n",
402 xprt, atomic_read(&xprt->xpt_ref.refcount));
403
404 return xprt;
405}
406
407/*
408 * svc_xprt_received conditionally queues the transport for processing
409 * by another thread. The caller must hold the XPT_BUSY bit and must
410 * not thereafter touch transport data.
411 *
412 * Note: XPT_DATA only gets cleared when a read-attempt finds no (or
413 * insufficient) data.
414 */
415void svc_xprt_received(struct svc_xprt *xprt)
416{
417 BUG_ON(!test_bit(XPT_BUSY, &xprt->xpt_flags));
418 /* As soon as we clear busy, the xprt could be closed and
419 * 'put', so we need a reference to call svc_xprt_enqueue with:
420 */
421 svc_xprt_get(xprt);
422 clear_bit(XPT_BUSY, &xprt->xpt_flags);
423 svc_xprt_enqueue(xprt);
424 svc_xprt_put(xprt);
425}
426EXPORT_SYMBOL_GPL(svc_xprt_received);
427
428/**
429 * svc_reserve - change the space reserved for the reply to a request.
430 * @rqstp: The request in question
431 * @space: new max space to reserve
432 *
433 * Each request reserves some space on the output queue of the transport
434 * to make sure the reply fits. This function reduces that reserved
435 * space to be the amount of space used already, plus @space.
436 *
437 */
438void svc_reserve(struct svc_rqst *rqstp, int space)
439{
440 space += rqstp->rq_res.head[0].iov_len;
441
442 if (space < rqstp->rq_reserved) {
443 struct svc_xprt *xprt = rqstp->rq_xprt;
444 atomic_sub((rqstp->rq_reserved - space), &xprt->xpt_reserved);
445 rqstp->rq_reserved = space;
446
447 svc_xprt_enqueue(xprt);
448 }
449}
450EXPORT_SYMBOL_GPL(svc_reserve);
451
452static void svc_xprt_release(struct svc_rqst *rqstp)
453{
454 struct svc_xprt *xprt = rqstp->rq_xprt;
455
456 rqstp->rq_xprt->xpt_ops->xpo_release_rqst(rqstp);
457
458 kfree(rqstp->rq_deferred);
459 rqstp->rq_deferred = NULL;
460
461 svc_free_res_pages(rqstp);
462 rqstp->rq_res.page_len = 0;
463 rqstp->rq_res.page_base = 0;
464
465 /* Reset response buffer and release
466 * the reservation.
467 * But first, check that enough space was reserved
468 * for the reply, otherwise we have a bug!
469 */
470 if ((rqstp->rq_res.len) > rqstp->rq_reserved)
471 printk(KERN_ERR "RPC request reserved %d but used %d\n",
472 rqstp->rq_reserved,
473 rqstp->rq_res.len);
474
475 rqstp->rq_res.head[0].iov_len = 0;
476 svc_reserve(rqstp, 0);
477 rqstp->rq_xprt = NULL;
478
479 svc_xprt_put(xprt);
480}
481
482/*
483 * External function to wake up a server waiting for data
484 * This really only makes sense for services like lockd
485 * which have exactly one thread anyway.
486 */
487void svc_wake_up(struct svc_serv *serv)
488{
489 struct svc_rqst *rqstp;
490 unsigned int i;
491 struct svc_pool *pool;
492
493 for (i = 0; i < serv->sv_nrpools; i++) {
494 pool = &serv->sv_pools[i];
495
496 spin_lock_bh(&pool->sp_lock);
497 if (!list_empty(&pool->sp_threads)) {
498 rqstp = list_entry(pool->sp_threads.next,
499 struct svc_rqst,
500 rq_list);
501 dprintk("svc: daemon %p woken up.\n", rqstp);
502 /*
503 svc_thread_dequeue(pool, rqstp);
504 rqstp->rq_xprt = NULL;
505 */
506 wake_up(&rqstp->rq_wait);
507 }
508 spin_unlock_bh(&pool->sp_lock);
509 }
510}
511EXPORT_SYMBOL_GPL(svc_wake_up);
512
513int svc_port_is_privileged(struct sockaddr *sin)
514{
515 switch (sin->sa_family) {
516 case AF_INET:
517 return ntohs(((struct sockaddr_in *)sin)->sin_port)
518 < PROT_SOCK;
519 case AF_INET6:
520 return ntohs(((struct sockaddr_in6 *)sin)->sin6_port)
521 < PROT_SOCK;
522 default:
523 return 0;
524 }
525}
526
527/*
528 * Make sure that we don't have too many active connections. If we have,
529 * something must be dropped. It's not clear what will happen if we allow
530 * "too many" connections, but when dealing with network-facing software,
531 * we have to code defensively. Here we do that by imposing hard limits.
532 *
533 * There's no point in trying to do random drop here for DoS
534 * prevention. The NFS clients does 1 reconnect in 15 seconds. An
535 * attacker can easily beat that.
536 *
537 * The only somewhat efficient mechanism would be if drop old
538 * connections from the same IP first. But right now we don't even
539 * record the client IP in svc_sock.
540 *
541 * single-threaded services that expect a lot of clients will probably
542 * need to set sv_maxconn to override the default value which is based
543 * on the number of threads
544 */
545static void svc_check_conn_limits(struct svc_serv *serv)
546{
547 unsigned int limit = serv->sv_maxconn ? serv->sv_maxconn :
548 (serv->sv_nrthreads+3) * 20;
549
550 if (serv->sv_tmpcnt > limit) {
551 struct svc_xprt *xprt = NULL;
552 spin_lock_bh(&serv->sv_lock);
553 if (!list_empty(&serv->sv_tempsocks)) {
554 if (net_ratelimit()) {
555 /* Try to help the admin */
556 printk(KERN_NOTICE "%s: too many open "
557 "connections, consider increasing %s\n",
558 serv->sv_name, serv->sv_maxconn ?
559 "the max number of connections." :
560 "the number of threads.");
561 }
562 /*
563 * Always select the oldest connection. It's not fair,
564 * but so is life
565 */
566 xprt = list_entry(serv->sv_tempsocks.prev,
567 struct svc_xprt,
568 xpt_list);
569 set_bit(XPT_CLOSE, &xprt->xpt_flags);
570 svc_xprt_get(xprt);
571 }
572 spin_unlock_bh(&serv->sv_lock);
573
574 if (xprt) {
575 svc_xprt_enqueue(xprt);
576 svc_xprt_put(xprt);
577 }
578 }
579}
580
581/*
582 * Receive the next request on any transport. This code is carefully
583 * organised not to touch any cachelines in the shared svc_serv
584 * structure, only cachelines in the local svc_pool.
585 */
586int svc_recv(struct svc_rqst *rqstp, long timeout)
587{
588 struct svc_xprt *xprt = NULL;
589 struct svc_serv *serv = rqstp->rq_server;
590 struct svc_pool *pool = rqstp->rq_pool;
591 int len, i;
592 int pages;
593 struct xdr_buf *arg;
594 DECLARE_WAITQUEUE(wait, current);
595 long time_left;
596
597 dprintk("svc: server %p waiting for data (to = %ld)\n",
598 rqstp, timeout);
599
600 if (rqstp->rq_xprt)
601 printk(KERN_ERR
602 "svc_recv: service %p, transport not NULL!\n",
603 rqstp);
604 if (waitqueue_active(&rqstp->rq_wait))
605 printk(KERN_ERR
606 "svc_recv: service %p, wait queue active!\n",
607 rqstp);
608
609 /* now allocate needed pages. If we get a failure, sleep briefly */
610 pages = (serv->sv_max_mesg + PAGE_SIZE) / PAGE_SIZE;
611 for (i = 0; i < pages ; i++)
612 while (rqstp->rq_pages[i] == NULL) {
613 struct page *p = alloc_page(GFP_KERNEL);
614 if (!p) {
615 set_current_state(TASK_INTERRUPTIBLE);
616 if (signalled() || kthread_should_stop()) {
617 set_current_state(TASK_RUNNING);
618 return -EINTR;
619 }
620 schedule_timeout(msecs_to_jiffies(500));
621 }
622 rqstp->rq_pages[i] = p;
623 }
624 rqstp->rq_pages[i++] = NULL; /* this might be seen in nfs_read_actor */
625 BUG_ON(pages >= RPCSVC_MAXPAGES);
626
627 /* Make arg->head point to first page and arg->pages point to rest */
628 arg = &rqstp->rq_arg;
629 arg->head[0].iov_base = page_address(rqstp->rq_pages[0]);
630 arg->head[0].iov_len = PAGE_SIZE;
631 arg->pages = rqstp->rq_pages + 1;
632 arg->page_base = 0;
633 /* save at least one page for response */
634 arg->page_len = (pages-2)*PAGE_SIZE;
635 arg->len = (pages-1)*PAGE_SIZE;
636 arg->tail[0].iov_len = 0;
637
638 try_to_freeze();
639 cond_resched();
640 if (signalled() || kthread_should_stop())
641 return -EINTR;
642
643 /* Normally we will wait up to 5 seconds for any required
644 * cache information to be provided.
645 */
646 rqstp->rq_chandle.thread_wait = 5*HZ;
647
648 spin_lock_bh(&pool->sp_lock);
649 xprt = svc_xprt_dequeue(pool);
650 if (xprt) {
651 rqstp->rq_xprt = xprt;
652 svc_xprt_get(xprt);
653 rqstp->rq_reserved = serv->sv_max_mesg;
654 atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
655
656 /* As there is a shortage of threads and this request
657 * had to be queued, don't allow the thread to wait so
658 * long for cache updates.
659 */
660 rqstp->rq_chandle.thread_wait = 1*HZ;
661 } else {
662 /* No data pending. Go to sleep */
663 svc_thread_enqueue(pool, rqstp);
664
665 /*
666 * We have to be able to interrupt this wait
667 * to bring down the daemons ...
668 */
669 set_current_state(TASK_INTERRUPTIBLE);
670
671 /*
672 * checking kthread_should_stop() here allows us to avoid
673 * locking and signalling when stopping kthreads that call
674 * svc_recv. If the thread has already been woken up, then
675 * we can exit here without sleeping. If not, then it
676 * it'll be woken up quickly during the schedule_timeout
677 */
678 if (kthread_should_stop()) {
679 set_current_state(TASK_RUNNING);
680 spin_unlock_bh(&pool->sp_lock);
681 return -EINTR;
682 }
683
684 add_wait_queue(&rqstp->rq_wait, &wait);
685 spin_unlock_bh(&pool->sp_lock);
686
687 time_left = schedule_timeout(timeout);
688
689 try_to_freeze();
690
691 spin_lock_bh(&pool->sp_lock);
692 remove_wait_queue(&rqstp->rq_wait, &wait);
693 if (!time_left)
694 pool->sp_stats.threads_timedout++;
695
696 xprt = rqstp->rq_xprt;
697 if (!xprt) {
698 svc_thread_dequeue(pool, rqstp);
699 spin_unlock_bh(&pool->sp_lock);
700 dprintk("svc: server %p, no data yet\n", rqstp);
701 if (signalled() || kthread_should_stop())
702 return -EINTR;
703 else
704 return -EAGAIN;
705 }
706 }
707 spin_unlock_bh(&pool->sp_lock);
708
709 len = 0;
710 if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) {
711 dprintk("svc_recv: found XPT_CLOSE\n");
712 svc_delete_xprt(xprt);
713 /* Leave XPT_BUSY set on the dead xprt: */
714 goto out;
715 }
716 if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) {
717 struct svc_xprt *newxpt;
718 newxpt = xprt->xpt_ops->xpo_accept(xprt);
719 if (newxpt) {
720 /*
721 * We know this module_get will succeed because the
722 * listener holds a reference too
723 */
724 __module_get(newxpt->xpt_class->xcl_owner);
725 svc_check_conn_limits(xprt->xpt_server);
726 spin_lock_bh(&serv->sv_lock);
727 set_bit(XPT_TEMP, &newxpt->xpt_flags);
728 list_add(&newxpt->xpt_list, &serv->sv_tempsocks);
729 serv->sv_tmpcnt++;
730 if (serv->sv_temptimer.function == NULL) {
731 /* setup timer to age temp transports */
732 setup_timer(&serv->sv_temptimer,
733 svc_age_temp_xprts,
734 (unsigned long)serv);
735 mod_timer(&serv->sv_temptimer,
736 jiffies + svc_conn_age_period * HZ);
737 }
738 spin_unlock_bh(&serv->sv_lock);
739 svc_xprt_received(newxpt);
740 }
741 } else if (xprt->xpt_ops->xpo_has_wspace(xprt)) {
742 dprintk("svc: server %p, pool %u, transport %p, inuse=%d\n",
743 rqstp, pool->sp_id, xprt,
744 atomic_read(&xprt->xpt_ref.refcount));
745 rqstp->rq_deferred = svc_deferred_dequeue(xprt);
746 if (rqstp->rq_deferred)
747 len = svc_deferred_recv(rqstp);
748 else
749 len = xprt->xpt_ops->xpo_recvfrom(rqstp);
750 dprintk("svc: got len=%d\n", len);
751 }
752 svc_xprt_received(xprt);
753
754 /* No data, incomplete (TCP) read, or accept() */
755 if (len == 0 || len == -EAGAIN)
756 goto out;
757
758 clear_bit(XPT_OLD, &xprt->xpt_flags);
759
760 rqstp->rq_secure = svc_port_is_privileged(svc_addr(rqstp));
761 rqstp->rq_chandle.defer = svc_defer;
762
763 if (serv->sv_stats)
764 serv->sv_stats->netcnt++;
765 return len;
766out:
767 rqstp->rq_res.len = 0;
768 svc_xprt_release(rqstp);
769 return -EAGAIN;
770}
771EXPORT_SYMBOL_GPL(svc_recv);
772
773/*
774 * Drop request
775 */
776void svc_drop(struct svc_rqst *rqstp)
777{
778 dprintk("svc: xprt %p dropped request\n", rqstp->rq_xprt);
779 svc_xprt_release(rqstp);
780}
781EXPORT_SYMBOL_GPL(svc_drop);
782
783/*
784 * Return reply to client.
785 */
786int svc_send(struct svc_rqst *rqstp)
787{
788 struct svc_xprt *xprt;
789 int len;
790 struct xdr_buf *xb;
791
792 xprt = rqstp->rq_xprt;
793 if (!xprt)
794 return -EFAULT;
795
796 /* release the receive skb before sending the reply */
797 rqstp->rq_xprt->xpt_ops->xpo_release_rqst(rqstp);
798
799 /* calculate over-all length */
800 xb = &rqstp->rq_res;
801 xb->len = xb->head[0].iov_len +
802 xb->page_len +
803 xb->tail[0].iov_len;
804
805 /* Grab mutex to serialize outgoing data. */
806 mutex_lock(&xprt->xpt_mutex);
807 if (test_bit(XPT_DEAD, &xprt->xpt_flags))
808 len = -ENOTCONN;
809 else
810 len = xprt->xpt_ops->xpo_sendto(rqstp);
811 mutex_unlock(&xprt->xpt_mutex);
812 rpc_wake_up(&xprt->xpt_bc_pending);
813 svc_xprt_release(rqstp);
814
815 if (len == -ECONNREFUSED || len == -ENOTCONN || len == -EAGAIN)
816 return 0;
817 return len;
818}
819
820/*
821 * Timer function to close old temporary transports, using
822 * a mark-and-sweep algorithm.
823 */
824static void svc_age_temp_xprts(unsigned long closure)
825{
826 struct svc_serv *serv = (struct svc_serv *)closure;
827 struct svc_xprt *xprt;
828 struct list_head *le, *next;
829 LIST_HEAD(to_be_aged);
830
831 dprintk("svc_age_temp_xprts\n");
832
833 if (!spin_trylock_bh(&serv->sv_lock)) {
834 /* busy, try again 1 sec later */
835 dprintk("svc_age_temp_xprts: busy\n");
836 mod_timer(&serv->sv_temptimer, jiffies + HZ);
837 return;
838 }
839
840 list_for_each_safe(le, next, &serv->sv_tempsocks) {
841 xprt = list_entry(le, struct svc_xprt, xpt_list);
842
843 /* First time through, just mark it OLD. Second time
844 * through, close it. */
845 if (!test_and_set_bit(XPT_OLD, &xprt->xpt_flags))
846 continue;
847 if (atomic_read(&xprt->xpt_ref.refcount) > 1 ||
848 test_bit(XPT_BUSY, &xprt->xpt_flags))
849 continue;
850 svc_xprt_get(xprt);
851 list_move(le, &to_be_aged);
852 set_bit(XPT_CLOSE, &xprt->xpt_flags);
853 set_bit(XPT_DETACHED, &xprt->xpt_flags);
854 }
855 spin_unlock_bh(&serv->sv_lock);
856
857 while (!list_empty(&to_be_aged)) {
858 le = to_be_aged.next;
859 /* fiddling the xpt_list node is safe 'cos we're XPT_DETACHED */
860 list_del_init(le);
861 xprt = list_entry(le, struct svc_xprt, xpt_list);
862
863 dprintk("queuing xprt %p for closing\n", xprt);
864
865 /* a thread will dequeue and close it soon */
866 svc_xprt_enqueue(xprt);
867 svc_xprt_put(xprt);
868 }
869
870 mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ);
871}
872
873static void call_xpt_users(struct svc_xprt *xprt)
874{
875 struct svc_xpt_user *u;
876
877 spin_lock(&xprt->xpt_lock);
878 while (!list_empty(&xprt->xpt_users)) {
879 u = list_first_entry(&xprt->xpt_users, struct svc_xpt_user, list);
880 list_del(&u->list);
881 u->callback(u);
882 }
883 spin_unlock(&xprt->xpt_lock);
884}
885
886/*
887 * Remove a dead transport
888 */
889void svc_delete_xprt(struct svc_xprt *xprt)
890{
891 struct svc_serv *serv = xprt->xpt_server;
892 struct svc_deferred_req *dr;
893
894 /* Only do this once */
895 if (test_and_set_bit(XPT_DEAD, &xprt->xpt_flags))
896 BUG();
897
898 dprintk("svc: svc_delete_xprt(%p)\n", xprt);
899 xprt->xpt_ops->xpo_detach(xprt);
900
901 spin_lock_bh(&serv->sv_lock);
902 if (!test_and_set_bit(XPT_DETACHED, &xprt->xpt_flags))
903 list_del_init(&xprt->xpt_list);
904 /*
905 * The only time we're called while xpt_ready is still on a list
906 * is while the list itself is about to be destroyed (in
907 * svc_destroy). BUT svc_xprt_enqueue could still be attempting
908 * to add new entries to the sp_sockets list, so we can't leave
909 * a freed xprt on it.
910 */
911 list_del_init(&xprt->xpt_ready);
912 if (test_bit(XPT_TEMP, &xprt->xpt_flags))
913 serv->sv_tmpcnt--;
914 spin_unlock_bh(&serv->sv_lock);
915
916 while ((dr = svc_deferred_dequeue(xprt)) != NULL)
917 kfree(dr);
918
919 call_xpt_users(xprt);
920 svc_xprt_put(xprt);
921}
922
923void svc_close_xprt(struct svc_xprt *xprt)
924{
925 set_bit(XPT_CLOSE, &xprt->xpt_flags);
926 if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
927 /* someone else will have to effect the close */
928 return;
929 /*
930 * We expect svc_close_xprt() to work even when no threads are
931 * running (e.g., while configuring the server before starting
932 * any threads), so if the transport isn't busy, we delete
933 * it ourself:
934 */
935 svc_delete_xprt(xprt);
936}
937EXPORT_SYMBOL_GPL(svc_close_xprt);
938
939void svc_close_all(struct list_head *xprt_list)
940{
941 struct svc_xprt *xprt;
942 struct svc_xprt *tmp;
943
944 /*
945 * The server is shutting down, and no more threads are running.
946 * svc_xprt_enqueue() might still be running, but at worst it
947 * will re-add the xprt to sp_sockets, which will soon get
948 * freed. So we don't bother with any more locking, and don't
949 * leave the close to the (nonexistent) server threads:
950 */
951 list_for_each_entry_safe(xprt, tmp, xprt_list, xpt_list) {
952 set_bit(XPT_CLOSE, &xprt->xpt_flags);
953 svc_delete_xprt(xprt);
954 }
955}
956
957/*
958 * Handle defer and revisit of requests
959 */
960
961static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
962{
963 struct svc_deferred_req *dr =
964 container_of(dreq, struct svc_deferred_req, handle);
965 struct svc_xprt *xprt = dr->xprt;
966
967 spin_lock(&xprt->xpt_lock);
968 set_bit(XPT_DEFERRED, &xprt->xpt_flags);
969 if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) {
970 spin_unlock(&xprt->xpt_lock);
971 dprintk("revisit canceled\n");
972 svc_xprt_put(xprt);
973 kfree(dr);
974 return;
975 }
976 dprintk("revisit queued\n");
977 dr->xprt = NULL;
978 list_add(&dr->handle.recent, &xprt->xpt_deferred);
979 spin_unlock(&xprt->xpt_lock);
980 svc_xprt_enqueue(xprt);
981 svc_xprt_put(xprt);
982}
983
984/*
985 * Save the request off for later processing. The request buffer looks
986 * like this:
987 *
988 * <xprt-header><rpc-header><rpc-pagelist><rpc-tail>
989 *
990 * This code can only handle requests that consist of an xprt-header
991 * and rpc-header.
992 */
993static struct cache_deferred_req *svc_defer(struct cache_req *req)
994{
995 struct svc_rqst *rqstp = container_of(req, struct svc_rqst, rq_chandle);
996 struct svc_deferred_req *dr;
997
998 if (rqstp->rq_arg.page_len || !rqstp->rq_usedeferral)
999 return NULL; /* if more than a page, give up FIXME */
1000 if (rqstp->rq_deferred) {
1001 dr = rqstp->rq_deferred;
1002 rqstp->rq_deferred = NULL;
1003 } else {
1004 size_t skip;
1005 size_t size;
1006 /* FIXME maybe discard if size too large */
1007 size = sizeof(struct svc_deferred_req) + rqstp->rq_arg.len;
1008 dr = kmalloc(size, GFP_KERNEL);
1009 if (dr == NULL)
1010 return NULL;
1011
1012 dr->handle.owner = rqstp->rq_server;
1013 dr->prot = rqstp->rq_prot;
1014 memcpy(&dr->addr, &rqstp->rq_addr, rqstp->rq_addrlen);
1015 dr->addrlen = rqstp->rq_addrlen;
1016 dr->daddr = rqstp->rq_daddr;
1017 dr->argslen = rqstp->rq_arg.len >> 2;
1018 dr->xprt_hlen = rqstp->rq_xprt_hlen;
1019
1020 /* back up head to the start of the buffer and copy */
1021 skip = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len;
1022 memcpy(dr->args, rqstp->rq_arg.head[0].iov_base - skip,
1023 dr->argslen << 2);
1024 }
1025 svc_xprt_get(rqstp->rq_xprt);
1026 dr->xprt = rqstp->rq_xprt;
1027 rqstp->rq_dropme = true;
1028
1029 dr->handle.revisit = svc_revisit;
1030 return &dr->handle;
1031}
1032
1033/*
1034 * recv data from a deferred request into an active one
1035 */
1036static int svc_deferred_recv(struct svc_rqst *rqstp)
1037{
1038 struct svc_deferred_req *dr = rqstp->rq_deferred;
1039
1040 /* setup iov_base past transport header */
1041 rqstp->rq_arg.head[0].iov_base = dr->args + (dr->xprt_hlen>>2);
1042 /* The iov_len does not include the transport header bytes */
1043 rqstp->rq_arg.head[0].iov_len = (dr->argslen<<2) - dr->xprt_hlen;
1044 rqstp->rq_arg.page_len = 0;
1045 /* The rq_arg.len includes the transport header bytes */
1046 rqstp->rq_arg.len = dr->argslen<<2;
1047 rqstp->rq_prot = dr->prot;
1048 memcpy(&rqstp->rq_addr, &dr->addr, dr->addrlen);
1049 rqstp->rq_addrlen = dr->addrlen;
1050 /* Save off transport header len in case we get deferred again */
1051 rqstp->rq_xprt_hlen = dr->xprt_hlen;
1052 rqstp->rq_daddr = dr->daddr;
1053 rqstp->rq_respages = rqstp->rq_pages;
1054 return (dr->argslen<<2) - dr->xprt_hlen;
1055}
1056
1057
1058static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt)
1059{
1060 struct svc_deferred_req *dr = NULL;
1061
1062 if (!test_bit(XPT_DEFERRED, &xprt->xpt_flags))
1063 return NULL;
1064 spin_lock(&xprt->xpt_lock);
1065 if (!list_empty(&xprt->xpt_deferred)) {
1066 dr = list_entry(xprt->xpt_deferred.next,
1067 struct svc_deferred_req,
1068 handle.recent);
1069 list_del_init(&dr->handle.recent);
1070 } else
1071 clear_bit(XPT_DEFERRED, &xprt->xpt_flags);
1072 spin_unlock(&xprt->xpt_lock);
1073 return dr;
1074}
1075
1076/**
1077 * svc_find_xprt - find an RPC transport instance
1078 * @serv: pointer to svc_serv to search
1079 * @xcl_name: C string containing transport's class name
1080 * @af: Address family of transport's local address
1081 * @port: transport's IP port number
1082 *
1083 * Return the transport instance pointer for the endpoint accepting
1084 * connections/peer traffic from the specified transport class,
1085 * address family and port.
1086 *
1087 * Specifying 0 for the address family or port is effectively a
1088 * wild-card, and will result in matching the first transport in the
1089 * service's list that has a matching class name.
1090 */
1091struct svc_xprt *svc_find_xprt(struct svc_serv *serv, const char *xcl_name,
1092 const sa_family_t af, const unsigned short port)
1093{
1094 struct svc_xprt *xprt;
1095 struct svc_xprt *found = NULL;
1096
1097 /* Sanity check the args */
1098 if (serv == NULL || xcl_name == NULL)
1099 return found;
1100
1101 spin_lock_bh(&serv->sv_lock);
1102 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1103 if (strcmp(xprt->xpt_class->xcl_name, xcl_name))
1104 continue;
1105 if (af != AF_UNSPEC && af != xprt->xpt_local.ss_family)
1106 continue;
1107 if (port != 0 && port != svc_xprt_local_port(xprt))
1108 continue;
1109 found = xprt;
1110 svc_xprt_get(xprt);
1111 break;
1112 }
1113 spin_unlock_bh(&serv->sv_lock);
1114 return found;
1115}
1116EXPORT_SYMBOL_GPL(svc_find_xprt);
1117
1118static int svc_one_xprt_name(const struct svc_xprt *xprt,
1119 char *pos, int remaining)
1120{
1121 int len;
1122
1123 len = snprintf(pos, remaining, "%s %u\n",
1124 xprt->xpt_class->xcl_name,
1125 svc_xprt_local_port(xprt));
1126 if (len >= remaining)
1127 return -ENAMETOOLONG;
1128 return len;
1129}
1130
1131/**
1132 * svc_xprt_names - format a buffer with a list of transport names
1133 * @serv: pointer to an RPC service
1134 * @buf: pointer to a buffer to be filled in
1135 * @buflen: length of buffer to be filled in
1136 *
1137 * Fills in @buf with a string containing a list of transport names,
1138 * each name terminated with '\n'.
1139 *
1140 * Returns positive length of the filled-in string on success; otherwise
1141 * a negative errno value is returned if an error occurs.
1142 */
1143int svc_xprt_names(struct svc_serv *serv, char *buf, const int buflen)
1144{
1145 struct svc_xprt *xprt;
1146 int len, totlen;
1147 char *pos;
1148
1149 /* Sanity check args */
1150 if (!serv)
1151 return 0;
1152
1153 spin_lock_bh(&serv->sv_lock);
1154
1155 pos = buf;
1156 totlen = 0;
1157 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1158 len = svc_one_xprt_name(xprt, pos, buflen - totlen);
1159 if (len < 0) {
1160 *buf = '\0';
1161 totlen = len;
1162 }
1163 if (len <= 0)
1164 break;
1165
1166 pos += len;
1167 totlen += len;
1168 }
1169
1170 spin_unlock_bh(&serv->sv_lock);
1171 return totlen;
1172}
1173EXPORT_SYMBOL_GPL(svc_xprt_names);
1174
1175
1176/*----------------------------------------------------------------------------*/
1177
1178static void *svc_pool_stats_start(struct seq_file *m, loff_t *pos)
1179{
1180 unsigned int pidx = (unsigned int)*pos;
1181 struct svc_serv *serv = m->private;
1182
1183 dprintk("svc_pool_stats_start, *pidx=%u\n", pidx);
1184
1185 if (!pidx)
1186 return SEQ_START_TOKEN;
1187 return (pidx > serv->sv_nrpools ? NULL : &serv->sv_pools[pidx-1]);
1188}
1189
1190static void *svc_pool_stats_next(struct seq_file *m, void *p, loff_t *pos)
1191{
1192 struct svc_pool *pool = p;
1193 struct svc_serv *serv = m->private;
1194
1195 dprintk("svc_pool_stats_next, *pos=%llu\n", *pos);
1196
1197 if (p == SEQ_START_TOKEN) {
1198 pool = &serv->sv_pools[0];
1199 } else {
1200 unsigned int pidx = (pool - &serv->sv_pools[0]);
1201 if (pidx < serv->sv_nrpools-1)
1202 pool = &serv->sv_pools[pidx+1];
1203 else
1204 pool = NULL;
1205 }
1206 ++*pos;
1207 return pool;
1208}
1209
1210static void svc_pool_stats_stop(struct seq_file *m, void *p)
1211{
1212}
1213
1214static int svc_pool_stats_show(struct seq_file *m, void *p)
1215{
1216 struct svc_pool *pool = p;
1217
1218 if (p == SEQ_START_TOKEN) {
1219 seq_puts(m, "# pool packets-arrived sockets-enqueued threads-woken threads-timedout\n");
1220 return 0;
1221 }
1222
1223 seq_printf(m, "%u %lu %lu %lu %lu\n",
1224 pool->sp_id,
1225 pool->sp_stats.packets,
1226 pool->sp_stats.sockets_queued,
1227 pool->sp_stats.threads_woken,
1228 pool->sp_stats.threads_timedout);
1229
1230 return 0;
1231}
1232
1233static const struct seq_operations svc_pool_stats_seq_ops = {
1234 .start = svc_pool_stats_start,
1235 .next = svc_pool_stats_next,
1236 .stop = svc_pool_stats_stop,
1237 .show = svc_pool_stats_show,
1238};
1239
1240int svc_pool_stats_open(struct svc_serv *serv, struct file *file)
1241{
1242 int err;
1243
1244 err = seq_open(file, &svc_pool_stats_seq_ops);
1245 if (!err)
1246 ((struct seq_file *) file->private_data)->private = serv;
1247 return err;
1248}
1249EXPORT_SYMBOL(svc_pool_stats_open);
1250
1251/*----------------------------------------------------------------------------*/