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_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 */
77
78/**
79 * svc_reg_xprt_class - Register a server-side RPC transport class
80 * @xcl: New transport class to be registered
81 *
82 * Returns zero on success; otherwise a negative errno is returned.
83 */
84int svc_reg_xprt_class(struct svc_xprt_class *xcl)
85{
86 struct svc_xprt_class *cl;
87 int res = -EEXIST;
88
89 INIT_LIST_HEAD(list: &xcl->xcl_list);
90 spin_lock(lock: &svc_xprt_class_lock);
91 /* Make sure there isn't already a class with the same name */
92 list_for_each_entry(cl, &svc_xprt_class_list, xcl_list) {
93 if (strcmp(xcl->xcl_name, cl->xcl_name) == 0)
94 goto out;
95 }
96 list_add_tail(new: &xcl->xcl_list, head: &svc_xprt_class_list);
97 res = 0;
98out:
99 spin_unlock(lock: &svc_xprt_class_lock);
100 return res;
101}
102EXPORT_SYMBOL_GPL(svc_reg_xprt_class);
103
104/**
105 * svc_unreg_xprt_class - Unregister a server-side RPC transport class
106 * @xcl: Transport class to be unregistered
107 *
108 */
109void svc_unreg_xprt_class(struct svc_xprt_class *xcl)
110{
111 spin_lock(lock: &svc_xprt_class_lock);
112 list_del_init(entry: &xcl->xcl_list);
113 spin_unlock(lock: &svc_xprt_class_lock);
114}
115EXPORT_SYMBOL_GPL(svc_unreg_xprt_class);
116
117/**
118 * svc_print_xprts - Format the transport list for printing
119 * @buf: target buffer for formatted address
120 * @maxlen: length of target buffer
121 *
122 * Fills in @buf with a string containing a list of transport names, each name
123 * terminated with '\n'. If the buffer is too small, some entries may be
124 * missing, but it is guaranteed that all lines in the output buffer are
125 * complete.
126 *
127 * Returns positive length of the filled-in string.
128 */
129int svc_print_xprts(char *buf, int maxlen)
130{
131 struct svc_xprt_class *xcl;
132 char tmpstr[80];
133 int len = 0;
134 buf[0] = '\0';
135
136 spin_lock(lock: &svc_xprt_class_lock);
137 list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
138 int slen;
139
140 slen = snprintf(buf: tmpstr, size: sizeof(tmpstr), fmt: "%s %d\n",
141 xcl->xcl_name, xcl->xcl_max_payload);
142 if (slen >= sizeof(tmpstr) || len + slen >= maxlen)
143 break;
144 len += slen;
145 strcat(p: buf, q: tmpstr);
146 }
147 spin_unlock(lock: &svc_xprt_class_lock);
148
149 return len;
150}
151
152/**
153 * svc_xprt_deferred_close - Close a transport
154 * @xprt: transport instance
155 *
156 * Used in contexts that need to defer the work of shutting down
157 * the transport to an nfsd thread.
158 */
159void svc_xprt_deferred_close(struct svc_xprt *xprt)
160{
161 if (!test_and_set_bit(nr: XPT_CLOSE, addr: &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(xpt: xprt);
173 put_cred(cred: xprt->xpt_cred);
174 put_net_track(net: xprt->xpt_net, tracker: &xprt->ns_tracker);
175 /* See comment on corresponding get in xs_setup_bc_tcp(): */
176 if (xprt->xpt_bc_xprt)
177 xprt_put(xprt: xprt->xpt_bc_xprt);
178 if (xprt->xpt_bc_xps)
179 xprt_switch_put(xps: xprt->xpt_bc_xps);
180 trace_svc_xprt_free(xprt);
181 xprt->xpt_ops->xpo_free(xprt);
182 module_put(module: owner);
183}
184
185void svc_xprt_put(struct svc_xprt *xprt)
186{
187 kref_put(kref: &xprt->xpt_ref, release: 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(kref: &xprt->xpt_ref);
202 xprt->xpt_server = serv;
203 INIT_LIST_HEAD(list: &xprt->xpt_list);
204 INIT_LIST_HEAD(list: &xprt->xpt_deferred);
205 INIT_LIST_HEAD(list: &xprt->xpt_users);
206 mutex_init(&xprt->xpt_mutex);
207 spin_lock_init(&xprt->xpt_lock);
208 set_bit(nr: XPT_BUSY, addr: &xprt->xpt_flags);
209 xprt->xpt_net = get_net_track(net, tracker: &xprt->ns_tracker, GFP_ATOMIC);
210 strcpy(p: xprt->xpt_remotebuf, q: "uninitialized");
211}
212EXPORT_SYMBOL_GPL(svc_xprt_init);
213
214static struct svc_xprt *__svc_xpo_create(struct svc_xprt_class *xcl,
215 struct svc_serv *serv,
216 struct net *net,
217 const int family,
218 const unsigned short port,
219 int flags)
220{
221 struct sockaddr_in sin = {
222 .sin_family = AF_INET,
223 .sin_addr.s_addr = htonl(INADDR_ANY),
224 .sin_port = htons(port),
225 };
226#if IS_ENABLED(CONFIG_IPV6)
227 struct sockaddr_in6 sin6 = {
228 .sin6_family = AF_INET6,
229 .sin6_addr = IN6ADDR_ANY_INIT,
230 .sin6_port = htons(port),
231 };
232#endif
233 struct svc_xprt *xprt;
234 struct sockaddr *sap;
235 size_t len;
236
237 switch (family) {
238 case PF_INET:
239 sap = (struct sockaddr *)&sin;
240 len = sizeof(sin);
241 break;
242#if IS_ENABLED(CONFIG_IPV6)
243 case PF_INET6:
244 sap = (struct sockaddr *)&sin6;
245 len = sizeof(sin6);
246 break;
247#endif
248 default:
249 return ERR_PTR(error: -EAFNOSUPPORT);
250 }
251
252 xprt = xcl->xcl_ops->xpo_create(serv, net, sap, len, flags);
253 if (IS_ERR(ptr: xprt))
254 trace_svc_xprt_create_err(program: serv->sv_program->pg_name,
255 protocol: xcl->xcl_name, sap, salen: len, xprt);
256 return xprt;
257}
258
259/**
260 * svc_xprt_received - start next receiver thread
261 * @xprt: controlling transport
262 *
263 * The caller must hold the XPT_BUSY bit and must
264 * not thereafter touch transport data.
265 *
266 * Note: XPT_DATA only gets cleared when a read-attempt finds no (or
267 * insufficient) data.
268 */
269void svc_xprt_received(struct svc_xprt *xprt)
270{
271 if (!test_bit(XPT_BUSY, &xprt->xpt_flags)) {
272 WARN_ONCE(1, "xprt=0x%p already busy!", xprt);
273 return;
274 }
275
276 /* As soon as we clear busy, the xprt could be closed and
277 * 'put', so we need a reference to call svc_xprt_enqueue with:
278 */
279 svc_xprt_get(xprt);
280 smp_mb__before_atomic();
281 clear_bit(nr: XPT_BUSY, addr: &xprt->xpt_flags);
282 svc_xprt_enqueue(xprt);
283 svc_xprt_put(xprt);
284}
285EXPORT_SYMBOL_GPL(svc_xprt_received);
286
287void svc_add_new_perm_xprt(struct svc_serv *serv, struct svc_xprt *new)
288{
289 clear_bit(nr: XPT_TEMP, addr: &new->xpt_flags);
290 spin_lock_bh(lock: &serv->sv_lock);
291 list_add(new: &new->xpt_list, head: &serv->sv_permsocks);
292 spin_unlock_bh(lock: &serv->sv_lock);
293 svc_xprt_received(new);
294}
295
296static int _svc_xprt_create(struct svc_serv *serv, const char *xprt_name,
297 struct net *net, const int family,
298 const unsigned short port, int flags,
299 const struct cred *cred)
300{
301 struct svc_xprt_class *xcl;
302
303 spin_lock(lock: &svc_xprt_class_lock);
304 list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
305 struct svc_xprt *newxprt;
306 unsigned short newport;
307
308 if (strcmp(xprt_name, xcl->xcl_name))
309 continue;
310
311 if (!try_module_get(module: xcl->xcl_owner))
312 goto err;
313
314 spin_unlock(lock: &svc_xprt_class_lock);
315 newxprt = __svc_xpo_create(xcl, serv, net, family, port, flags);
316 if (IS_ERR(ptr: newxprt)) {
317 module_put(module: xcl->xcl_owner);
318 return PTR_ERR(ptr: newxprt);
319 }
320 newxprt->xpt_cred = get_cred(cred);
321 svc_add_new_perm_xprt(serv, new: newxprt);
322 newport = svc_xprt_local_port(xprt: newxprt);
323 return newport;
324 }
325 err:
326 spin_unlock(lock: &svc_xprt_class_lock);
327 /* This errno is exposed to user space. Provide a reasonable
328 * perror msg for a bad transport. */
329 return -EPROTONOSUPPORT;
330}
331
332/**
333 * svc_xprt_create - Add a new listener to @serv
334 * @serv: target RPC service
335 * @xprt_name: transport class name
336 * @net: network namespace
337 * @family: network address family
338 * @port: listener port
339 * @flags: SVC_SOCK flags
340 * @cred: credential to bind to this transport
341 *
342 * Return values:
343 * %0: New listener added successfully
344 * %-EPROTONOSUPPORT: Requested transport type not supported
345 */
346int svc_xprt_create(struct svc_serv *serv, const char *xprt_name,
347 struct net *net, const int family,
348 const unsigned short port, int flags,
349 const struct cred *cred)
350{
351 int err;
352
353 err = _svc_xprt_create(serv, xprt_name, net, family, port, flags, cred);
354 if (err == -EPROTONOSUPPORT) {
355 request_module("svc%s", xprt_name);
356 err = _svc_xprt_create(serv, xprt_name, net, family, port, flags, cred);
357 }
358 return err;
359}
360EXPORT_SYMBOL_GPL(svc_xprt_create);
361
362/*
363 * Copy the local and remote xprt addresses to the rqstp structure
364 */
365void svc_xprt_copy_addrs(struct svc_rqst *rqstp, struct svc_xprt *xprt)
366{
367 memcpy(&rqstp->rq_addr, &xprt->xpt_remote, xprt->xpt_remotelen);
368 rqstp->rq_addrlen = xprt->xpt_remotelen;
369
370 /*
371 * Destination address in request is needed for binding the
372 * source address in RPC replies/callbacks later.
373 */
374 memcpy(&rqstp->rq_daddr, &xprt->xpt_local, xprt->xpt_locallen);
375 rqstp->rq_daddrlen = xprt->xpt_locallen;
376}
377EXPORT_SYMBOL_GPL(svc_xprt_copy_addrs);
378
379/**
380 * svc_print_addr - Format rq_addr field for printing
381 * @rqstp: svc_rqst struct containing address to print
382 * @buf: target buffer for formatted address
383 * @len: length of target buffer
384 *
385 */
386char *svc_print_addr(struct svc_rqst *rqstp, char *buf, size_t len)
387{
388 return __svc_print_addr(addr: svc_addr(rqst: rqstp), buf, len);
389}
390EXPORT_SYMBOL_GPL(svc_print_addr);
391
392static bool svc_xprt_slots_in_range(struct svc_xprt *xprt)
393{
394 unsigned int limit = svc_rpc_per_connection_limit;
395 int nrqsts = atomic_read(v: &xprt->xpt_nr_rqsts);
396
397 return limit == 0 || (nrqsts >= 0 && nrqsts < limit);
398}
399
400static bool svc_xprt_reserve_slot(struct svc_rqst *rqstp, struct svc_xprt *xprt)
401{
402 if (!test_bit(RQ_DATA, &rqstp->rq_flags)) {
403 if (!svc_xprt_slots_in_range(xprt))
404 return false;
405 atomic_inc(v: &xprt->xpt_nr_rqsts);
406 set_bit(nr: RQ_DATA, addr: &rqstp->rq_flags);
407 }
408 return true;
409}
410
411static void svc_xprt_release_slot(struct svc_rqst *rqstp)
412{
413 struct svc_xprt *xprt = rqstp->rq_xprt;
414 if (test_and_clear_bit(nr: RQ_DATA, addr: &rqstp->rq_flags)) {
415 atomic_dec(v: &xprt->xpt_nr_rqsts);
416 smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */
417 svc_xprt_enqueue(xprt);
418 }
419}
420
421static bool svc_xprt_ready(struct svc_xprt *xprt)
422{
423 unsigned long xpt_flags;
424
425 /*
426 * If another cpu has recently updated xpt_flags,
427 * sk_sock->flags, xpt_reserved, or xpt_nr_rqsts, we need to
428 * know about it; otherwise it's possible that both that cpu and
429 * this one could call svc_xprt_enqueue() without either
430 * svc_xprt_enqueue() recognizing that the conditions below
431 * are satisfied, and we could stall indefinitely:
432 */
433 smp_rmb();
434 xpt_flags = READ_ONCE(xprt->xpt_flags);
435
436 trace_svc_xprt_enqueue(xprt, flags: xpt_flags);
437 if (xpt_flags & BIT(XPT_BUSY))
438 return false;
439 if (xpt_flags & (BIT(XPT_CONN) | BIT(XPT_CLOSE) | BIT(XPT_HANDSHAKE)))
440 return true;
441 if (xpt_flags & (BIT(XPT_DATA) | BIT(XPT_DEFERRED))) {
442 if (xprt->xpt_ops->xpo_has_wspace(xprt) &&
443 svc_xprt_slots_in_range(xprt))
444 return true;
445 trace_svc_xprt_no_write_space(xprt);
446 return false;
447 }
448 return false;
449}
450
451/**
452 * svc_xprt_enqueue - Queue a transport on an idle nfsd thread
453 * @xprt: transport with data pending
454 *
455 */
456void svc_xprt_enqueue(struct svc_xprt *xprt)
457{
458 struct svc_pool *pool;
459
460 if (!svc_xprt_ready(xprt))
461 return;
462
463 /* Mark transport as busy. It will remain in this state until
464 * the provider calls svc_xprt_received. We update XPT_BUSY
465 * atomically because it also guards against trying to enqueue
466 * the transport twice.
467 */
468 if (test_and_set_bit(nr: XPT_BUSY, addr: &xprt->xpt_flags))
469 return;
470
471 pool = svc_pool_for_cpu(serv: xprt->xpt_server);
472
473 percpu_counter_inc(fbc: &pool->sp_sockets_queued);
474 lwq_enqueue(n: &xprt->xpt_ready, q: &pool->sp_xprts);
475
476 svc_pool_wake_idle_thread(pool);
477}
478EXPORT_SYMBOL_GPL(svc_xprt_enqueue);
479
480/*
481 * Dequeue the first transport, if there is one.
482 */
483static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool)
484{
485 struct svc_xprt *xprt = NULL;
486
487 xprt = lwq_dequeue(&pool->sp_xprts, struct svc_xprt, xpt_ready);
488 if (xprt)
489 svc_xprt_get(xprt);
490 return xprt;
491}
492
493/**
494 * svc_reserve - change the space reserved for the reply to a request.
495 * @rqstp: The request in question
496 * @space: new max space to reserve
497 *
498 * Each request reserves some space on the output queue of the transport
499 * to make sure the reply fits. This function reduces that reserved
500 * space to be the amount of space used already, plus @space.
501 *
502 */
503void svc_reserve(struct svc_rqst *rqstp, int space)
504{
505 struct svc_xprt *xprt = rqstp->rq_xprt;
506
507 space += rqstp->rq_res.head[0].iov_len;
508
509 if (xprt && space < rqstp->rq_reserved) {
510 atomic_sub(i: (rqstp->rq_reserved - space), v: &xprt->xpt_reserved);
511 rqstp->rq_reserved = space;
512 smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */
513 svc_xprt_enqueue(xprt);
514 }
515}
516EXPORT_SYMBOL_GPL(svc_reserve);
517
518static void free_deferred(struct svc_xprt *xprt, struct svc_deferred_req *dr)
519{
520 if (!dr)
521 return;
522
523 xprt->xpt_ops->xpo_release_ctxt(xprt, dr->xprt_ctxt);
524 kfree(objp: dr);
525}
526
527static void svc_xprt_release(struct svc_rqst *rqstp)
528{
529 struct svc_xprt *xprt = rqstp->rq_xprt;
530
531 xprt->xpt_ops->xpo_release_ctxt(xprt, rqstp->rq_xprt_ctxt);
532 rqstp->rq_xprt_ctxt = NULL;
533
534 free_deferred(xprt, dr: rqstp->rq_deferred);
535 rqstp->rq_deferred = NULL;
536
537 svc_rqst_release_pages(rqstp);
538 rqstp->rq_res.page_len = 0;
539 rqstp->rq_res.page_base = 0;
540
541 /* Reset response buffer and release
542 * the reservation.
543 * But first, check that enough space was reserved
544 * for the reply, otherwise we have a bug!
545 */
546 if ((rqstp->rq_res.len) > rqstp->rq_reserved)
547 printk(KERN_ERR "RPC request reserved %d but used %d\n",
548 rqstp->rq_reserved,
549 rqstp->rq_res.len);
550
551 rqstp->rq_res.head[0].iov_len = 0;
552 svc_reserve(rqstp, 0);
553 svc_xprt_release_slot(rqstp);
554 rqstp->rq_xprt = NULL;
555 svc_xprt_put(xprt);
556}
557
558/**
559 * svc_wake_up - Wake up a service thread for non-transport work
560 * @serv: RPC service
561 *
562 * Some svc_serv's will have occasional work to do, even when a xprt is not
563 * waiting to be serviced. This function is there to "kick" a task in one of
564 * those services so that it can wake up and do that work. Note that we only
565 * bother with pool 0 as we don't need to wake up more than one thread for
566 * this purpose.
567 */
568void svc_wake_up(struct svc_serv *serv)
569{
570 struct svc_pool *pool = &serv->sv_pools[0];
571
572 set_bit(nr: SP_TASK_PENDING, addr: &pool->sp_flags);
573 svc_pool_wake_idle_thread(pool);
574}
575EXPORT_SYMBOL_GPL(svc_wake_up);
576
577int svc_port_is_privileged(struct sockaddr *sin)
578{
579 switch (sin->sa_family) {
580 case AF_INET:
581 return ntohs(((struct sockaddr_in *)sin)->sin_port)
582 < PROT_SOCK;
583 case AF_INET6:
584 return ntohs(((struct sockaddr_in6 *)sin)->sin6_port)
585 < PROT_SOCK;
586 default:
587 return 0;
588 }
589}
590
591/*
592 * Make sure that we don't have too many active connections. If we have,
593 * something must be dropped. It's not clear what will happen if we allow
594 * "too many" connections, but when dealing with network-facing software,
595 * we have to code defensively. Here we do that by imposing hard limits.
596 *
597 * There's no point in trying to do random drop here for DoS
598 * prevention. The NFS clients does 1 reconnect in 15 seconds. An
599 * attacker can easily beat that.
600 *
601 * The only somewhat efficient mechanism would be if drop old
602 * connections from the same IP first. But right now we don't even
603 * record the client IP in svc_sock.
604 *
605 * single-threaded services that expect a lot of clients will probably
606 * need to set sv_maxconn to override the default value which is based
607 * on the number of threads
608 */
609static void svc_check_conn_limits(struct svc_serv *serv)
610{
611 unsigned int limit = serv->sv_maxconn ? serv->sv_maxconn :
612 (serv->sv_nrthreads+3) * 20;
613
614 if (serv->sv_tmpcnt > limit) {
615 struct svc_xprt *xprt = NULL;
616 spin_lock_bh(lock: &serv->sv_lock);
617 if (!list_empty(head: &serv->sv_tempsocks)) {
618 /* Try to help the admin */
619 net_notice_ratelimited("%s: too many open connections, consider increasing the %s\n",
620 serv->sv_name, serv->sv_maxconn ?
621 "max number of connections" :
622 "number of threads");
623 /*
624 * Always select the oldest connection. It's not fair,
625 * but so is life
626 */
627 xprt = list_entry(serv->sv_tempsocks.prev,
628 struct svc_xprt,
629 xpt_list);
630 set_bit(nr: XPT_CLOSE, addr: &xprt->xpt_flags);
631 svc_xprt_get(xprt);
632 }
633 spin_unlock_bh(lock: &serv->sv_lock);
634
635 if (xprt) {
636 svc_xprt_enqueue(xprt);
637 svc_xprt_put(xprt);
638 }
639 }
640}
641
642static bool svc_alloc_arg(struct svc_rqst *rqstp)
643{
644 struct svc_serv *serv = rqstp->rq_server;
645 struct xdr_buf *arg = &rqstp->rq_arg;
646 unsigned long pages, filled, ret;
647
648 pages = (serv->sv_max_mesg + 2 * PAGE_SIZE) >> PAGE_SHIFT;
649 if (pages > RPCSVC_MAXPAGES) {
650 pr_warn_once("svc: warning: pages=%lu > RPCSVC_MAXPAGES=%lu\n",
651 pages, RPCSVC_MAXPAGES);
652 /* use as many pages as possible */
653 pages = RPCSVC_MAXPAGES;
654 }
655
656 for (filled = 0; filled < pages; filled = ret) {
657 ret = alloc_pages_bulk_array_node(GFP_KERNEL,
658 nid: rqstp->rq_pool->sp_id,
659 nr_pages: pages, page_array: rqstp->rq_pages);
660 if (ret > filled)
661 /* Made progress, don't sleep yet */
662 continue;
663
664 set_current_state(TASK_IDLE);
665 if (svc_thread_should_stop(rqstp)) {
666 set_current_state(TASK_RUNNING);
667 return false;
668 }
669 trace_svc_alloc_arg_err(requested: pages, allocated: ret);
670 memalloc_retry_wait(GFP_KERNEL);
671 }
672 rqstp->rq_page_end = &rqstp->rq_pages[pages];
673 rqstp->rq_pages[pages] = NULL; /* this might be seen in nfsd_splice_actor() */
674
675 /* Make arg->head point to first page and arg->pages point to rest */
676 arg->head[0].iov_base = page_address(rqstp->rq_pages[0]);
677 arg->head[0].iov_len = PAGE_SIZE;
678 arg->pages = rqstp->rq_pages + 1;
679 arg->page_base = 0;
680 /* save at least one page for response */
681 arg->page_len = (pages-2)*PAGE_SIZE;
682 arg->len = (pages-1)*PAGE_SIZE;
683 arg->tail[0].iov_len = 0;
684
685 rqstp->rq_xid = xdr_zero;
686 return true;
687}
688
689static bool
690svc_thread_should_sleep(struct svc_rqst *rqstp)
691{
692 struct svc_pool *pool = rqstp->rq_pool;
693
694 /* did someone call svc_wake_up? */
695 if (test_bit(SP_TASK_PENDING, &pool->sp_flags))
696 return false;
697
698 /* was a socket queued? */
699 if (!lwq_empty(q: &pool->sp_xprts))
700 return false;
701
702 /* are we shutting down? */
703 if (svc_thread_should_stop(rqstp))
704 return false;
705
706#if defined(CONFIG_SUNRPC_BACKCHANNEL)
707 if (svc_is_backchannel(rqstp)) {
708 if (!lwq_empty(q: &rqstp->rq_server->sv_cb_list))
709 return false;
710 }
711#endif
712
713 return true;
714}
715
716static void svc_thread_wait_for_work(struct svc_rqst *rqstp)
717{
718 struct svc_pool *pool = rqstp->rq_pool;
719
720 if (svc_thread_should_sleep(rqstp)) {
721 set_current_state(TASK_IDLE | TASK_FREEZABLE);
722 llist_add(new: &rqstp->rq_idle, head: &pool->sp_idle_threads);
723 if (likely(svc_thread_should_sleep(rqstp)))
724 schedule();
725
726 while (!llist_del_first_this(head: &pool->sp_idle_threads,
727 this: &rqstp->rq_idle)) {
728 /* Work just became available. This thread can only
729 * handle it after removing rqstp from the idle
730 * list. If that attempt failed, some other thread
731 * must have queued itself after finding no
732 * work to do, so that thread has taken responsibly
733 * for this new work. This thread can safely sleep
734 * until woken again.
735 */
736 schedule();
737 set_current_state(TASK_IDLE | TASK_FREEZABLE);
738 }
739 __set_current_state(TASK_RUNNING);
740 } else {
741 cond_resched();
742 }
743 try_to_freeze();
744}
745
746static void svc_add_new_temp_xprt(struct svc_serv *serv, struct svc_xprt *newxpt)
747{
748 spin_lock_bh(lock: &serv->sv_lock);
749 set_bit(nr: XPT_TEMP, addr: &newxpt->xpt_flags);
750 list_add(new: &newxpt->xpt_list, head: &serv->sv_tempsocks);
751 serv->sv_tmpcnt++;
752 if (serv->sv_temptimer.function == NULL) {
753 /* setup timer to age temp transports */
754 serv->sv_temptimer.function = svc_age_temp_xprts;
755 mod_timer(timer: &serv->sv_temptimer,
756 expires: jiffies + svc_conn_age_period * HZ);
757 }
758 spin_unlock_bh(lock: &serv->sv_lock);
759 svc_xprt_received(newxpt);
760}
761
762static void svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
763{
764 struct svc_serv *serv = rqstp->rq_server;
765 int len = 0;
766
767 if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) {
768 if (test_and_clear_bit(nr: XPT_KILL_TEMP, addr: &xprt->xpt_flags))
769 xprt->xpt_ops->xpo_kill_temp_xprt(xprt);
770 svc_delete_xprt(xprt);
771 /* Leave XPT_BUSY set on the dead xprt: */
772 goto out;
773 }
774 if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) {
775 struct svc_xprt *newxpt;
776 /*
777 * We know this module_get will succeed because the
778 * listener holds a reference too
779 */
780 __module_get(module: xprt->xpt_class->xcl_owner);
781 svc_check_conn_limits(serv: xprt->xpt_server);
782 newxpt = xprt->xpt_ops->xpo_accept(xprt);
783 if (newxpt) {
784 newxpt->xpt_cred = get_cred(cred: xprt->xpt_cred);
785 svc_add_new_temp_xprt(serv, newxpt);
786 trace_svc_xprt_accept(xprt: newxpt, service: serv->sv_name);
787 } else {
788 module_put(module: xprt->xpt_class->xcl_owner);
789 }
790 svc_xprt_received(xprt);
791 } else if (test_bit(XPT_HANDSHAKE, &xprt->xpt_flags)) {
792 xprt->xpt_ops->xpo_handshake(xprt);
793 svc_xprt_received(xprt);
794 } else if (svc_xprt_reserve_slot(rqstp, xprt)) {
795 /* XPT_DATA|XPT_DEFERRED case: */
796 rqstp->rq_deferred = svc_deferred_dequeue(xprt);
797 if (rqstp->rq_deferred)
798 len = svc_deferred_recv(rqstp);
799 else
800 len = xprt->xpt_ops->xpo_recvfrom(rqstp);
801 rqstp->rq_reserved = serv->sv_max_mesg;
802 atomic_add(i: rqstp->rq_reserved, v: &xprt->xpt_reserved);
803 if (len <= 0)
804 goto out;
805
806 trace_svc_xdr_recvfrom(xdr: &rqstp->rq_arg);
807
808 clear_bit(nr: XPT_OLD, addr: &xprt->xpt_flags);
809
810 rqstp->rq_chandle.defer = svc_defer;
811
812 if (serv->sv_stats)
813 serv->sv_stats->netcnt++;
814 percpu_counter_inc(fbc: &rqstp->rq_pool->sp_messages_arrived);
815 rqstp->rq_stime = ktime_get();
816 svc_process(rqstp);
817 } else
818 svc_xprt_received(xprt);
819
820out:
821 rqstp->rq_res.len = 0;
822 svc_xprt_release(rqstp);
823}
824
825static void svc_thread_wake_next(struct svc_rqst *rqstp)
826{
827 if (!svc_thread_should_sleep(rqstp))
828 /* More work pending after I dequeued some,
829 * wake another worker
830 */
831 svc_pool_wake_idle_thread(pool: rqstp->rq_pool);
832}
833
834/**
835 * svc_recv - Receive and process the next request on any transport
836 * @rqstp: an idle RPC service thread
837 *
838 * This code is carefully organised not to touch any cachelines in
839 * the shared svc_serv structure, only cachelines in the local
840 * svc_pool.
841 */
842void svc_recv(struct svc_rqst *rqstp)
843{
844 struct svc_pool *pool = rqstp->rq_pool;
845
846 if (!svc_alloc_arg(rqstp))
847 return;
848
849 svc_thread_wait_for_work(rqstp);
850
851 clear_bit(nr: SP_TASK_PENDING, addr: &pool->sp_flags);
852
853 if (svc_thread_should_stop(rqstp)) {
854 svc_thread_wake_next(rqstp);
855 return;
856 }
857
858 rqstp->rq_xprt = svc_xprt_dequeue(pool);
859 if (rqstp->rq_xprt) {
860 struct svc_xprt *xprt = rqstp->rq_xprt;
861
862 svc_thread_wake_next(rqstp);
863 /* Normally we will wait up to 5 seconds for any required
864 * cache information to be provided. When there are no
865 * idle threads, we reduce the wait time.
866 */
867 if (pool->sp_idle_threads.first)
868 rqstp->rq_chandle.thread_wait = 5 * HZ;
869 else
870 rqstp->rq_chandle.thread_wait = 1 * HZ;
871
872 trace_svc_xprt_dequeue(rqst: rqstp);
873 svc_handle_xprt(rqstp, xprt);
874 }
875
876#if defined(CONFIG_SUNRPC_BACKCHANNEL)
877 if (svc_is_backchannel(rqstp)) {
878 struct svc_serv *serv = rqstp->rq_server;
879 struct rpc_rqst *req;
880
881 req = lwq_dequeue(&serv->sv_cb_list,
882 struct rpc_rqst, rq_bc_list);
883 if (req) {
884 svc_thread_wake_next(rqstp);
885 svc_process_bc(req, rqstp);
886 }
887 }
888#endif
889}
890EXPORT_SYMBOL_GPL(svc_recv);
891
892/*
893 * Drop request
894 */
895void svc_drop(struct svc_rqst *rqstp)
896{
897 trace_svc_drop(rqst: rqstp);
898}
899EXPORT_SYMBOL_GPL(svc_drop);
900
901/**
902 * svc_send - Return reply to client
903 * @rqstp: RPC transaction context
904 *
905 */
906void svc_send(struct svc_rqst *rqstp)
907{
908 struct svc_xprt *xprt;
909 struct xdr_buf *xb;
910 int status;
911
912 xprt = rqstp->rq_xprt;
913
914 /* calculate over-all length */
915 xb = &rqstp->rq_res;
916 xb->len = xb->head[0].iov_len +
917 xb->page_len +
918 xb->tail[0].iov_len;
919 trace_svc_xdr_sendto(xid: rqstp->rq_xid, xdr: xb);
920 trace_svc_stats_latency(rqst: rqstp);
921
922 status = xprt->xpt_ops->xpo_sendto(rqstp);
923
924 trace_svc_send(rqst: rqstp, status);
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(lock: &serv->sv_lock)) {
940 /* busy, try again 1 sec later */
941 dprintk("svc_age_temp_xprts: busy\n");
942 mod_timer(timer: &serv->sv_temptimer, expires: 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(nr: XPT_OLD, addr: &xprt->xpt_flags))
952 continue;
953 if (kref_read(kref: &xprt->xpt_ref) > 1 ||
954 test_bit(XPT_BUSY, &xprt->xpt_flags))
955 continue;
956 list_del_init(entry: le);
957 set_bit(nr: XPT_CLOSE, addr: &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(lock: &serv->sv_lock);
964
965 mod_timer(timer: &serv->sv_temptimer, expires: 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(lock: &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(sap1: server_addr, sap2: (struct sockaddr *)
984 &xprt->xpt_local)) {
985 dprintk("svc_age_temp_xprts_now: found %p\n", xprt);
986 list_move(list: le, head: &to_be_closed);
987 }
988 }
989 spin_unlock_bh(lock: &serv->sv_lock);
990
991 while (!list_empty(head: &to_be_closed)) {
992 le = to_be_closed.next;
993 list_del_init(entry: le);
994 xprt = list_entry(le, struct svc_xprt, xpt_list);
995 set_bit(nr: XPT_CLOSE, addr: &xprt->xpt_flags);
996 set_bit(nr: XPT_KILL_TEMP, addr: &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(lock: &xprt->xpt_lock);
1009 while (!list_empty(head: &xprt->xpt_users)) {
1010 u = list_first_entry(&xprt->xpt_users, struct svc_xpt_user, list);
1011 list_del_init(entry: &u->list);
1012 u->callback(u);
1013 }
1014 spin_unlock(lock: &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 if (test_and_set_bit(nr: XPT_DEAD, addr: &xprt->xpt_flags))
1026 return;
1027
1028 trace_svc_xprt_detach(xprt);
1029 xprt->xpt_ops->xpo_detach(xprt);
1030 if (xprt->xpt_bc_xprt)
1031 xprt->xpt_bc_xprt->ops->close(xprt->xpt_bc_xprt);
1032
1033 spin_lock_bh(lock: &serv->sv_lock);
1034 list_del_init(entry: &xprt->xpt_list);
1035 if (test_bit(XPT_TEMP, &xprt->xpt_flags))
1036 serv->sv_tmpcnt--;
1037 spin_unlock_bh(lock: &serv->sv_lock);
1038
1039 while ((dr = svc_deferred_dequeue(xprt)) != NULL)
1040 free_deferred(xprt, dr);
1041
1042 call_xpt_users(xprt);
1043 svc_xprt_put(xprt);
1044}
1045
1046/**
1047 * svc_xprt_close - Close a client connection
1048 * @xprt: transport to disconnect
1049 *
1050 */
1051void svc_xprt_close(struct svc_xprt *xprt)
1052{
1053 trace_svc_xprt_close(xprt);
1054 set_bit(nr: XPT_CLOSE, addr: &xprt->xpt_flags);
1055 if (test_and_set_bit(nr: XPT_BUSY, addr: &xprt->xpt_flags))
1056 /* someone else will have to effect the close */
1057 return;
1058 /*
1059 * We expect svc_close_xprt() to work even when no threads are
1060 * running (e.g., while configuring the server before starting
1061 * any threads), so if the transport isn't busy, we delete
1062 * it ourself:
1063 */
1064 svc_delete_xprt(xprt);
1065}
1066EXPORT_SYMBOL_GPL(svc_xprt_close);
1067
1068static int svc_close_list(struct svc_serv *serv, struct list_head *xprt_list, struct net *net)
1069{
1070 struct svc_xprt *xprt;
1071 int ret = 0;
1072
1073 spin_lock_bh(lock: &serv->sv_lock);
1074 list_for_each_entry(xprt, xprt_list, xpt_list) {
1075 if (xprt->xpt_net != net)
1076 continue;
1077 ret++;
1078 set_bit(nr: XPT_CLOSE, addr: &xprt->xpt_flags);
1079 svc_xprt_enqueue(xprt);
1080 }
1081 spin_unlock_bh(lock: &serv->sv_lock);
1082 return ret;
1083}
1084
1085static void svc_clean_up_xprts(struct svc_serv *serv, struct net *net)
1086{
1087 struct svc_xprt *xprt;
1088 int i;
1089
1090 for (i = 0; i < serv->sv_nrpools; i++) {
1091 struct svc_pool *pool = &serv->sv_pools[i];
1092 struct llist_node *q, **t1, *t2;
1093
1094 q = lwq_dequeue_all(q: &pool->sp_xprts);
1095 lwq_for_each_safe(xprt, t1, t2, &q, xpt_ready) {
1096 if (xprt->xpt_net == net) {
1097 set_bit(nr: XPT_CLOSE, addr: &xprt->xpt_flags);
1098 svc_delete_xprt(xprt);
1099 xprt = NULL;
1100 }
1101 }
1102
1103 if (q)
1104 lwq_enqueue_batch(n: q, q: &pool->sp_xprts);
1105 }
1106}
1107
1108/**
1109 * svc_xprt_destroy_all - Destroy transports associated with @serv
1110 * @serv: RPC service to be shut down
1111 * @net: target network namespace
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_xprt_destroy_all(struct svc_serv *serv, struct net *net)
1125{
1126 int delay = 0;
1127
1128 while (svc_close_list(serv, xprt_list: &serv->sv_permsocks, net) +
1129 svc_close_list(serv, xprt_list: &serv->sv_tempsocks, net)) {
1130
1131 svc_clean_up_xprts(serv, net);
1132 msleep(msecs: delay++);
1133 }
1134}
1135EXPORT_SYMBOL_GPL(svc_xprt_destroy_all);
1136
1137/*
1138 * Handle defer and revisit of requests
1139 */
1140
1141static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
1142{
1143 struct svc_deferred_req *dr =
1144 container_of(dreq, struct svc_deferred_req, handle);
1145 struct svc_xprt *xprt = dr->xprt;
1146
1147 spin_lock(lock: &xprt->xpt_lock);
1148 set_bit(nr: XPT_DEFERRED, addr: &xprt->xpt_flags);
1149 if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) {
1150 spin_unlock(lock: &xprt->xpt_lock);
1151 trace_svc_defer_drop(dr);
1152 free_deferred(xprt, dr);
1153 svc_xprt_put(xprt);
1154 return;
1155 }
1156 dr->xprt = NULL;
1157 list_add(new: &dr->handle.recent, head: &xprt->xpt_deferred);
1158 spin_unlock(lock: &xprt->xpt_lock);
1159 trace_svc_defer_queue(dr);
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
1199 /* back up head to the start of the buffer and copy */
1200 skip = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len;
1201 memcpy(dr->args, rqstp->rq_arg.head[0].iov_base - skip,
1202 dr->argslen << 2);
1203 }
1204 dr->xprt_ctxt = rqstp->rq_xprt_ctxt;
1205 rqstp->rq_xprt_ctxt = NULL;
1206 trace_svc_defer(rqst: rqstp);
1207 svc_xprt_get(xprt: rqstp->rq_xprt);
1208 dr->xprt = rqstp->rq_xprt;
1209 set_bit(nr: RQ_DROPME, addr: &rqstp->rq_flags);
1210
1211 dr->handle.revisit = svc_revisit;
1212 return &dr->handle;
1213}
1214
1215/*
1216 * recv data from a deferred request into an active one
1217 */
1218static noinline int svc_deferred_recv(struct svc_rqst *rqstp)
1219{
1220 struct svc_deferred_req *dr = rqstp->rq_deferred;
1221
1222 trace_svc_defer_recv(dr);
1223
1224 /* setup iov_base past transport header */
1225 rqstp->rq_arg.head[0].iov_base = dr->args;
1226 /* The iov_len does not include the transport header bytes */
1227 rqstp->rq_arg.head[0].iov_len = dr->argslen << 2;
1228 rqstp->rq_arg.page_len = 0;
1229 /* The rq_arg.len includes the transport header bytes */
1230 rqstp->rq_arg.len = dr->argslen << 2;
1231 rqstp->rq_prot = dr->prot;
1232 memcpy(&rqstp->rq_addr, &dr->addr, dr->addrlen);
1233 rqstp->rq_addrlen = dr->addrlen;
1234 /* Save off transport header len in case we get deferred again */
1235 rqstp->rq_daddr = dr->daddr;
1236 rqstp->rq_respages = rqstp->rq_pages;
1237 rqstp->rq_xprt_ctxt = dr->xprt_ctxt;
1238
1239 dr->xprt_ctxt = NULL;
1240 svc_xprt_received(rqstp->rq_xprt);
1241 return dr->argslen << 2;
1242}
1243
1244
1245static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt)
1246{
1247 struct svc_deferred_req *dr = NULL;
1248
1249 if (!test_bit(XPT_DEFERRED, &xprt->xpt_flags))
1250 return NULL;
1251 spin_lock(lock: &xprt->xpt_lock);
1252 if (!list_empty(head: &xprt->xpt_deferred)) {
1253 dr = list_entry(xprt->xpt_deferred.next,
1254 struct svc_deferred_req,
1255 handle.recent);
1256 list_del_init(entry: &dr->handle.recent);
1257 } else
1258 clear_bit(nr: XPT_DEFERRED, addr: &xprt->xpt_flags);
1259 spin_unlock(lock: &xprt->xpt_lock);
1260 return dr;
1261}
1262
1263/**
1264 * svc_find_xprt - find an RPC transport instance
1265 * @serv: pointer to svc_serv to search
1266 * @xcl_name: C string containing transport's class name
1267 * @net: owner net pointer
1268 * @af: Address family of transport's local address
1269 * @port: transport's IP port number
1270 *
1271 * Return the transport instance pointer for the endpoint accepting
1272 * connections/peer traffic from the specified transport class,
1273 * address family and port.
1274 *
1275 * Specifying 0 for the address family or port is effectively a
1276 * wild-card, and will result in matching the first transport in the
1277 * service's list that has a matching class name.
1278 */
1279struct svc_xprt *svc_find_xprt(struct svc_serv *serv, const char *xcl_name,
1280 struct net *net, const sa_family_t af,
1281 const unsigned short port)
1282{
1283 struct svc_xprt *xprt;
1284 struct svc_xprt *found = NULL;
1285
1286 /* Sanity check the args */
1287 if (serv == NULL || xcl_name == NULL)
1288 return found;
1289
1290 spin_lock_bh(lock: &serv->sv_lock);
1291 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1292 if (xprt->xpt_net != net)
1293 continue;
1294 if (strcmp(xprt->xpt_class->xcl_name, xcl_name))
1295 continue;
1296 if (af != AF_UNSPEC && af != xprt->xpt_local.ss_family)
1297 continue;
1298 if (port != 0 && port != svc_xprt_local_port(xprt))
1299 continue;
1300 found = xprt;
1301 svc_xprt_get(xprt);
1302 break;
1303 }
1304 spin_unlock_bh(lock: &serv->sv_lock);
1305 return found;
1306}
1307EXPORT_SYMBOL_GPL(svc_find_xprt);
1308
1309static int svc_one_xprt_name(const struct svc_xprt *xprt,
1310 char *pos, int remaining)
1311{
1312 int len;
1313
1314 len = snprintf(buf: pos, size: remaining, fmt: "%s %u\n",
1315 xprt->xpt_class->xcl_name,
1316 svc_xprt_local_port(xprt));
1317 if (len >= remaining)
1318 return -ENAMETOOLONG;
1319 return len;
1320}
1321
1322/**
1323 * svc_xprt_names - format a buffer with a list of transport names
1324 * @serv: pointer to an RPC service
1325 * @buf: pointer to a buffer to be filled in
1326 * @buflen: length of buffer to be filled in
1327 *
1328 * Fills in @buf with a string containing a list of transport names,
1329 * each name terminated with '\n'.
1330 *
1331 * Returns positive length of the filled-in string on success; otherwise
1332 * a negative errno value is returned if an error occurs.
1333 */
1334int svc_xprt_names(struct svc_serv *serv, char *buf, const int buflen)
1335{
1336 struct svc_xprt *xprt;
1337 int len, totlen;
1338 char *pos;
1339
1340 /* Sanity check args */
1341 if (!serv)
1342 return 0;
1343
1344 spin_lock_bh(lock: &serv->sv_lock);
1345
1346 pos = buf;
1347 totlen = 0;
1348 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1349 len = svc_one_xprt_name(xprt, pos, remaining: buflen - totlen);
1350 if (len < 0) {
1351 *buf = '\0';
1352 totlen = len;
1353 }
1354 if (len <= 0)
1355 break;
1356
1357 pos += len;
1358 totlen += len;
1359 }
1360
1361 spin_unlock_bh(lock: &serv->sv_lock);
1362 return totlen;
1363}
1364EXPORT_SYMBOL_GPL(svc_xprt_names);
1365
1366
1367/*----------------------------------------------------------------------------*/
1368
1369static void *svc_pool_stats_start(struct seq_file *m, loff_t *pos)
1370{
1371 unsigned int pidx = (unsigned int)*pos;
1372 struct svc_serv *serv = m->private;
1373
1374 dprintk("svc_pool_stats_start, *pidx=%u\n", pidx);
1375
1376 if (!pidx)
1377 return SEQ_START_TOKEN;
1378 return (pidx > serv->sv_nrpools ? NULL : &serv->sv_pools[pidx-1]);
1379}
1380
1381static void *svc_pool_stats_next(struct seq_file *m, void *p, loff_t *pos)
1382{
1383 struct svc_pool *pool = p;
1384 struct svc_serv *serv = m->private;
1385
1386 dprintk("svc_pool_stats_next, *pos=%llu\n", *pos);
1387
1388 if (p == SEQ_START_TOKEN) {
1389 pool = &serv->sv_pools[0];
1390 } else {
1391 unsigned int pidx = (pool - &serv->sv_pools[0]);
1392 if (pidx < serv->sv_nrpools-1)
1393 pool = &serv->sv_pools[pidx+1];
1394 else
1395 pool = NULL;
1396 }
1397 ++*pos;
1398 return pool;
1399}
1400
1401static void svc_pool_stats_stop(struct seq_file *m, void *p)
1402{
1403}
1404
1405static int svc_pool_stats_show(struct seq_file *m, void *p)
1406{
1407 struct svc_pool *pool = p;
1408
1409 if (p == SEQ_START_TOKEN) {
1410 seq_puts(m, s: "# pool packets-arrived sockets-enqueued threads-woken threads-timedout\n");
1411 return 0;
1412 }
1413
1414 seq_printf(m, fmt: "%u %llu %llu %llu 0\n",
1415 pool->sp_id,
1416 percpu_counter_sum_positive(fbc: &pool->sp_messages_arrived),
1417 percpu_counter_sum_positive(fbc: &pool->sp_sockets_queued),
1418 percpu_counter_sum_positive(fbc: &pool->sp_threads_woken));
1419
1420 return 0;
1421}
1422
1423static const struct seq_operations svc_pool_stats_seq_ops = {
1424 .start = svc_pool_stats_start,
1425 .next = svc_pool_stats_next,
1426 .stop = svc_pool_stats_stop,
1427 .show = svc_pool_stats_show,
1428};
1429
1430int svc_pool_stats_open(struct svc_serv *serv, struct file *file)
1431{
1432 int err;
1433
1434 err = seq_open(file, &svc_pool_stats_seq_ops);
1435 if (!err)
1436 ((struct seq_file *) file->private_data)->private = serv;
1437 return err;
1438}
1439EXPORT_SYMBOL(svc_pool_stats_open);
1440
1441/*----------------------------------------------------------------------------*/
1442

source code of linux/net/sunrpc/svc_xprt.c