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
26 static unsigned int svc_rpc_per_connection_limit __read_mostly;
27 module_param(svc_rpc_per_connection_limit, uint, 0644);
28
29
30 static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt);
31 static int svc_deferred_recv(struct svc_rqst *rqstp);
32 static struct cache_deferred_req *svc_defer(struct cache_req *req);
33 static void svc_age_temp_xprts(struct timer_list *t);
34 static 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 */
41 static int svc_conn_age_period = 6*60;
42
43 /* List of registered transport classes */
44 static DEFINE_SPINLOCK(svc_xprt_class_lock);
45 static LIST_HEAD(svc_xprt_class_list);
46
47 /* SMP locking strategy:
48 *
49 * svc_serv->sv_lock protects sv_tempsocks, sv_permsocks, sv_tmpcnt.
50 * when both need to be taken (rare), svc_serv->sv_lock is first.
51 * The "service mutex" protects svc_serv->sv_nrthread.
52 * svc_sock->sk_lock protects the svc_sock->sk_deferred list
53 * and the ->sk_info_authunix cache.
54 *
55 * The XPT_BUSY bit in xprt->xpt_flags prevents a transport being
56 * enqueued multiply. During normal transport processing this bit
57 * is set by svc_xprt_enqueue and cleared by svc_xprt_received.
58 * Providers should not manipulate this bit directly.
59 *
60 * Some flags can be set to certain values at any time
61 * providing that certain rules are followed:
62 *
63 * XPT_CONN, XPT_DATA:
64 * - Can be set or cleared at any time.
65 * - After a set, svc_xprt_enqueue must be called to enqueue
66 * the transport for processing.
67 * - After a clear, the transport must be read/accepted.
68 * If this succeeds, it must be set again.
69 * XPT_CLOSE:
70 * - Can set at any time. It is never cleared.
71 * XPT_DEAD:
72 * - Can only be set while XPT_BUSY is held which ensures
73 * that no other thread will be using the transport or will
74 * try to set XPT_DEAD.
75 */
76
77 /**
78 * svc_reg_xprt_class - Register a server-side RPC transport class
79 * @xcl: New transport class to be registered
80 *
81 * Returns zero on success; otherwise a negative errno is returned.
82 */
svc_reg_xprt_class(struct svc_xprt_class * xcl)83 int svc_reg_xprt_class(struct svc_xprt_class *xcl)
84 {
85 struct svc_xprt_class *cl;
86 int res = -EEXIST;
87
88 INIT_LIST_HEAD(&xcl->xcl_list);
89 spin_lock(&svc_xprt_class_lock);
90 /* Make sure there isn't already a class with the same name */
91 list_for_each_entry(cl, &svc_xprt_class_list, xcl_list) {
92 if (strcmp(xcl->xcl_name, cl->xcl_name) == 0)
93 goto out;
94 }
95 list_add_tail(&xcl->xcl_list, &svc_xprt_class_list);
96 res = 0;
97 out:
98 spin_unlock(&svc_xprt_class_lock);
99 return res;
100 }
101 EXPORT_SYMBOL_GPL(svc_reg_xprt_class);
102
103 /**
104 * svc_unreg_xprt_class - Unregister a server-side RPC transport class
105 * @xcl: Transport class to be unregistered
106 *
107 */
svc_unreg_xprt_class(struct svc_xprt_class * xcl)108 void svc_unreg_xprt_class(struct svc_xprt_class *xcl)
109 {
110 spin_lock(&svc_xprt_class_lock);
111 list_del_init(&xcl->xcl_list);
112 spin_unlock(&svc_xprt_class_lock);
113 }
114 EXPORT_SYMBOL_GPL(svc_unreg_xprt_class);
115
116 /**
117 * svc_print_xprts - Format the transport list for printing
118 * @buf: target buffer for formatted address
119 * @maxlen: length of target buffer
120 *
121 * Fills in @buf with a string containing a list of transport names, each name
122 * terminated with '\n'. If the buffer is too small, some entries may be
123 * missing, but it is guaranteed that all lines in the output buffer are
124 * complete.
125 *
126 * Returns positive length of the filled-in string.
127 */
svc_print_xprts(char * buf,int maxlen)128 int svc_print_xprts(char *buf, int maxlen)
129 {
130 struct svc_xprt_class *xcl;
131 char tmpstr[80];
132 int len = 0;
133 buf[0] = '\0';
134
135 spin_lock(&svc_xprt_class_lock);
136 list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
137 int slen;
138
139 slen = snprintf(tmpstr, sizeof(tmpstr), "%s %d\n",
140 xcl->xcl_name, xcl->xcl_max_payload);
141 if (slen >= sizeof(tmpstr) || len + slen >= maxlen)
142 break;
143 len += slen;
144 strcat(buf, tmpstr);
145 }
146 spin_unlock(&svc_xprt_class_lock);
147
148 return len;
149 }
150
151 /**
152 * svc_xprt_deferred_close - Close a transport
153 * @xprt: transport instance
154 *
155 * Used in contexts that need to defer the work of shutting down
156 * the transport to an nfsd thread.
157 */
svc_xprt_deferred_close(struct svc_xprt * xprt)158 void svc_xprt_deferred_close(struct svc_xprt *xprt)
159 {
160 trace_svc_xprt_close(xprt);
161 if (!test_and_set_bit(XPT_CLOSE, &xprt->xpt_flags))
162 svc_xprt_enqueue(xprt);
163 }
164 EXPORT_SYMBOL_GPL(svc_xprt_deferred_close);
165
svc_xprt_free(struct kref * kref)166 static void svc_xprt_free(struct kref *kref)
167 {
168 struct svc_xprt *xprt =
169 container_of(kref, struct svc_xprt, xpt_ref);
170 struct module *owner = xprt->xpt_class->xcl_owner;
171 if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags))
172 svcauth_unix_info_release(xprt);
173 put_cred(xprt->xpt_cred);
174 put_net_track(xprt->xpt_net, &xprt->ns_tracker);
175 /* See comment on corresponding get in xs_setup_bc_tcp(): */
176 if (xprt->xpt_bc_xprt)
177 xprt_put(xprt->xpt_bc_xprt);
178 if (xprt->xpt_bc_xps)
179 xprt_switch_put(xprt->xpt_bc_xps);
180 trace_svc_xprt_free(xprt);
181 xprt->xpt_ops->xpo_free(xprt);
182 module_put(owner);
183 }
184
svc_xprt_put(struct svc_xprt * xprt)185 void svc_xprt_put(struct svc_xprt *xprt)
186 {
187 kref_put(&xprt->xpt_ref, svc_xprt_free);
188 }
189 EXPORT_SYMBOL_GPL(svc_xprt_put);
190
191 /*
192 * Called by transport drivers to initialize the transport independent
193 * portion of the transport instance.
194 */
svc_xprt_init(struct net * net,struct svc_xprt_class * xcl,struct svc_xprt * xprt,struct svc_serv * serv)195 void svc_xprt_init(struct net *net, struct svc_xprt_class *xcl,
196 struct svc_xprt *xprt, struct svc_serv *serv)
197 {
198 memset(xprt, 0, sizeof(*xprt));
199 xprt->xpt_class = xcl;
200 xprt->xpt_ops = xcl->xcl_ops;
201 kref_init(&xprt->xpt_ref);
202 xprt->xpt_server = serv;
203 INIT_LIST_HEAD(&xprt->xpt_list);
204 INIT_LIST_HEAD(&xprt->xpt_deferred);
205 INIT_LIST_HEAD(&xprt->xpt_users);
206 mutex_init(&xprt->xpt_mutex);
207 spin_lock_init(&xprt->xpt_lock);
208 set_bit(XPT_BUSY, &xprt->xpt_flags);
209 xprt->xpt_net = get_net_track(net, &xprt->ns_tracker, GFP_ATOMIC);
210 strcpy(xprt->xpt_remotebuf, "uninitialized");
211 }
212 EXPORT_SYMBOL_GPL(svc_xprt_init);
213
214 /**
215 * svc_xprt_received - start next receiver thread
216 * @xprt: controlling transport
217 *
218 * The caller must hold the XPT_BUSY bit and must
219 * not thereafter touch transport data.
220 *
221 * Note: XPT_DATA only gets cleared when a read-attempt finds no (or
222 * insufficient) data.
223 */
svc_xprt_received(struct svc_xprt * xprt)224 void svc_xprt_received(struct svc_xprt *xprt)
225 {
226 if (!test_bit(XPT_BUSY, &xprt->xpt_flags)) {
227 WARN_ONCE(1, "xprt=0x%p already busy!", xprt);
228 return;
229 }
230
231 /* As soon as we clear busy, the xprt could be closed and
232 * 'put', so we need a reference to call svc_xprt_enqueue with:
233 */
234 svc_xprt_get(xprt);
235 smp_mb__before_atomic();
236 clear_bit(XPT_BUSY, &xprt->xpt_flags);
237 svc_xprt_enqueue(xprt);
238 svc_xprt_put(xprt);
239 }
240 EXPORT_SYMBOL_GPL(svc_xprt_received);
241
svc_add_new_perm_xprt(struct svc_serv * serv,struct svc_xprt * new)242 void svc_add_new_perm_xprt(struct svc_serv *serv, struct svc_xprt *new)
243 {
244 clear_bit(XPT_TEMP, &new->xpt_flags);
245 spin_lock_bh(&serv->sv_lock);
246 list_add(&new->xpt_list, &serv->sv_permsocks);
247 spin_unlock_bh(&serv->sv_lock);
248 svc_xprt_received(new);
249 }
250
_svc_xprt_create(struct svc_serv * serv,const char * xprt_name,struct net * net,struct sockaddr * sap,size_t len,int flags,const struct cred * cred)251 static int _svc_xprt_create(struct svc_serv *serv, const char *xprt_name,
252 struct net *net, struct sockaddr *sap,
253 size_t len, int flags, const struct cred *cred)
254 {
255 struct svc_xprt_class *xcl;
256
257 spin_lock(&svc_xprt_class_lock);
258 list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
259 struct svc_xprt *newxprt;
260 unsigned short newport;
261
262 if (strcmp(xprt_name, xcl->xcl_name))
263 continue;
264
265 if (!try_module_get(xcl->xcl_owner))
266 goto err;
267
268 spin_unlock(&svc_xprt_class_lock);
269 newxprt = xcl->xcl_ops->xpo_create(serv, net, sap, len, flags);
270 if (IS_ERR(newxprt)) {
271 trace_svc_xprt_create_err(serv->sv_program->pg_name,
272 xcl->xcl_name, sap, len,
273 newxprt);
274 module_put(xcl->xcl_owner);
275 return PTR_ERR(newxprt);
276 }
277 newxprt->xpt_cred = get_cred(cred);
278 svc_add_new_perm_xprt(serv, newxprt);
279 newport = svc_xprt_local_port(newxprt);
280 return newport;
281 }
282 err:
283 spin_unlock(&svc_xprt_class_lock);
284 /* This errno is exposed to user space. Provide a reasonable
285 * perror msg for a bad transport. */
286 return -EPROTONOSUPPORT;
287 }
288
289 /**
290 * svc_xprt_create_from_sa - Add a new listener to @serv from socket address
291 * @serv: target RPC service
292 * @xprt_name: transport class name
293 * @net: network namespace
294 * @sap: socket address pointer
295 * @flags: SVC_SOCK flags
296 * @cred: credential to bind to this transport
297 *
298 * Return local xprt port on success or %-EPROTONOSUPPORT on failure
299 */
svc_xprt_create_from_sa(struct svc_serv * serv,const char * xprt_name,struct net * net,struct sockaddr * sap,int flags,const struct cred * cred)300 int svc_xprt_create_from_sa(struct svc_serv *serv, const char *xprt_name,
301 struct net *net, struct sockaddr *sap,
302 int flags, const struct cred *cred)
303 {
304 size_t len;
305 int err;
306
307 switch (sap->sa_family) {
308 case AF_INET:
309 len = sizeof(struct sockaddr_in);
310 break;
311 #if IS_ENABLED(CONFIG_IPV6)
312 case AF_INET6:
313 len = sizeof(struct sockaddr_in6);
314 break;
315 #endif
316 default:
317 return -EAFNOSUPPORT;
318 }
319
320 err = _svc_xprt_create(serv, xprt_name, net, sap, len, flags, cred);
321 if (err == -EPROTONOSUPPORT) {
322 request_module("svc%s", xprt_name);
323 err = _svc_xprt_create(serv, xprt_name, net, sap, len, flags,
324 cred);
325 }
326
327 return err;
328 }
329 EXPORT_SYMBOL_GPL(svc_xprt_create_from_sa);
330
331 /**
332 * svc_xprt_create - Add a new listener to @serv
333 * @serv: target RPC service
334 * @xprt_name: transport class name
335 * @net: network namespace
336 * @family: network address family
337 * @port: listener port
338 * @flags: SVC_SOCK flags
339 * @cred: credential to bind to this transport
340 *
341 * Return local xprt port on success or %-EPROTONOSUPPORT on failure
342 */
svc_xprt_create(struct svc_serv * serv,const char * xprt_name,struct net * net,const int family,const unsigned short port,int flags,const struct cred * cred)343 int svc_xprt_create(struct svc_serv *serv, const char *xprt_name,
344 struct net *net, const int family,
345 const unsigned short port, int flags,
346 const struct cred *cred)
347 {
348 struct sockaddr_in sin = {
349 .sin_family = AF_INET,
350 .sin_addr.s_addr = htonl(INADDR_ANY),
351 .sin_port = htons(port),
352 };
353 #if IS_ENABLED(CONFIG_IPV6)
354 struct sockaddr_in6 sin6 = {
355 .sin6_family = AF_INET6,
356 .sin6_addr = IN6ADDR_ANY_INIT,
357 .sin6_port = htons(port),
358 };
359 #endif
360 struct sockaddr *sap;
361
362 switch (family) {
363 case PF_INET:
364 sap = (struct sockaddr *)&sin;
365 break;
366 #if IS_ENABLED(CONFIG_IPV6)
367 case PF_INET6:
368 sap = (struct sockaddr *)&sin6;
369 break;
370 #endif
371 default:
372 return -EAFNOSUPPORT;
373 }
374
375 return svc_xprt_create_from_sa(serv, xprt_name, net, sap, flags, cred);
376 }
377 EXPORT_SYMBOL_GPL(svc_xprt_create);
378
379 /*
380 * Copy the local and remote xprt addresses to the rqstp structure
381 */
svc_xprt_copy_addrs(struct svc_rqst * rqstp,struct svc_xprt * xprt)382 void svc_xprt_copy_addrs(struct svc_rqst *rqstp, struct svc_xprt *xprt)
383 {
384 memcpy(&rqstp->rq_addr, &xprt->xpt_remote, xprt->xpt_remotelen);
385 rqstp->rq_addrlen = xprt->xpt_remotelen;
386
387 /*
388 * Destination address in request is needed for binding the
389 * source address in RPC replies/callbacks later.
390 */
391 memcpy(&rqstp->rq_daddr, &xprt->xpt_local, xprt->xpt_locallen);
392 rqstp->rq_daddrlen = xprt->xpt_locallen;
393 }
394 EXPORT_SYMBOL_GPL(svc_xprt_copy_addrs);
395
396 /**
397 * svc_print_addr - Format rq_addr field for printing
398 * @rqstp: svc_rqst struct containing address to print
399 * @buf: target buffer for formatted address
400 * @len: length of target buffer
401 *
402 */
svc_print_addr(struct svc_rqst * rqstp,char * buf,size_t len)403 char *svc_print_addr(struct svc_rqst *rqstp, char *buf, size_t len)
404 {
405 return __svc_print_addr(svc_addr(rqstp), buf, len);
406 }
407 EXPORT_SYMBOL_GPL(svc_print_addr);
408
svc_xprt_slots_in_range(struct svc_xprt * xprt)409 static bool svc_xprt_slots_in_range(struct svc_xprt *xprt)
410 {
411 unsigned int limit = svc_rpc_per_connection_limit;
412 int nrqsts = atomic_read(&xprt->xpt_nr_rqsts);
413
414 return limit == 0 || (nrqsts >= 0 && nrqsts < limit);
415 }
416
svc_xprt_reserve_slot(struct svc_rqst * rqstp,struct svc_xprt * xprt)417 static bool svc_xprt_reserve_slot(struct svc_rqst *rqstp, struct svc_xprt *xprt)
418 {
419 if (!test_bit(RQ_DATA, &rqstp->rq_flags)) {
420 if (!svc_xprt_slots_in_range(xprt))
421 return false;
422 atomic_inc(&xprt->xpt_nr_rqsts);
423 set_bit(RQ_DATA, &rqstp->rq_flags);
424 }
425 return true;
426 }
427
svc_xprt_release_slot(struct svc_rqst * rqstp)428 static void svc_xprt_release_slot(struct svc_rqst *rqstp)
429 {
430 struct svc_xprt *xprt = rqstp->rq_xprt;
431 if (test_and_clear_bit(RQ_DATA, &rqstp->rq_flags)) {
432 atomic_dec(&xprt->xpt_nr_rqsts);
433 smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */
434 svc_xprt_enqueue(xprt);
435 }
436 }
437
svc_xprt_ready(struct svc_xprt * xprt)438 static bool svc_xprt_ready(struct svc_xprt *xprt)
439 {
440 unsigned long xpt_flags;
441
442 /*
443 * If another cpu has recently updated xpt_flags,
444 * sk_sock->flags, xpt_reserved, or xpt_nr_rqsts, we need to
445 * know about it; otherwise it's possible that both that cpu and
446 * this one could call svc_xprt_enqueue() without either
447 * svc_xprt_enqueue() recognizing that the conditions below
448 * are satisfied, and we could stall indefinitely:
449 */
450 smp_rmb();
451 xpt_flags = READ_ONCE(xprt->xpt_flags);
452
453 trace_svc_xprt_enqueue(xprt, xpt_flags);
454 if (xpt_flags & BIT(XPT_BUSY))
455 return false;
456 if (xpt_flags & (BIT(XPT_CONN) | BIT(XPT_CLOSE) | BIT(XPT_HANDSHAKE)))
457 return true;
458 if (xpt_flags & (BIT(XPT_DATA) | BIT(XPT_DEFERRED))) {
459 if (xprt->xpt_ops->xpo_has_wspace(xprt) &&
460 svc_xprt_slots_in_range(xprt))
461 return true;
462 trace_svc_xprt_no_write_space(xprt);
463 return false;
464 }
465 return false;
466 }
467
468 /**
469 * svc_xprt_enqueue - Queue a transport on an idle nfsd thread
470 * @xprt: transport with data pending
471 *
472 */
svc_xprt_enqueue(struct svc_xprt * xprt)473 void svc_xprt_enqueue(struct svc_xprt *xprt)
474 {
475 struct svc_pool *pool;
476
477 if (!svc_xprt_ready(xprt))
478 return;
479
480 /* Mark transport as busy. It will remain in this state until
481 * the provider calls svc_xprt_received. We update XPT_BUSY
482 * atomically because it also guards against trying to enqueue
483 * the transport twice.
484 */
485 if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
486 return;
487
488 pool = svc_pool_for_cpu(xprt->xpt_server);
489
490 percpu_counter_inc(&pool->sp_sockets_queued);
491 lwq_enqueue(&xprt->xpt_ready, &pool->sp_xprts);
492
493 svc_pool_wake_idle_thread(pool);
494 }
495 EXPORT_SYMBOL_GPL(svc_xprt_enqueue);
496
497 /*
498 * Dequeue the first transport, if there is one.
499 */
svc_xprt_dequeue(struct svc_pool * pool)500 static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool)
501 {
502 struct svc_xprt *xprt = NULL;
503
504 xprt = lwq_dequeue(&pool->sp_xprts, struct svc_xprt, xpt_ready);
505 if (xprt)
506 svc_xprt_get(xprt);
507 return xprt;
508 }
509
510 /**
511 * svc_reserve - change the space reserved for the reply to a request.
512 * @rqstp: The request in question
513 * @space: new max space to reserve
514 *
515 * Each request reserves some space on the output queue of the transport
516 * to make sure the reply fits. This function reduces that reserved
517 * space to be the amount of space used already, plus @space.
518 *
519 */
svc_reserve(struct svc_rqst * rqstp,int space)520 void svc_reserve(struct svc_rqst *rqstp, int space)
521 {
522 struct svc_xprt *xprt = rqstp->rq_xprt;
523
524 space += rqstp->rq_res.head[0].iov_len;
525
526 if (xprt && space < rqstp->rq_reserved) {
527 atomic_sub((rqstp->rq_reserved - space), &xprt->xpt_reserved);
528 rqstp->rq_reserved = space;
529 smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */
530 svc_xprt_enqueue(xprt);
531 }
532 }
533 EXPORT_SYMBOL_GPL(svc_reserve);
534
free_deferred(struct svc_xprt * xprt,struct svc_deferred_req * dr)535 static void free_deferred(struct svc_xprt *xprt, struct svc_deferred_req *dr)
536 {
537 if (!dr)
538 return;
539
540 xprt->xpt_ops->xpo_release_ctxt(xprt, dr->xprt_ctxt);
541 kfree(dr);
542 }
543
svc_xprt_release(struct svc_rqst * rqstp)544 static void svc_xprt_release(struct svc_rqst *rqstp)
545 {
546 struct svc_xprt *xprt = rqstp->rq_xprt;
547
548 xprt->xpt_ops->xpo_release_ctxt(xprt, rqstp->rq_xprt_ctxt);
549 rqstp->rq_xprt_ctxt = NULL;
550
551 free_deferred(xprt, rqstp->rq_deferred);
552 rqstp->rq_deferred = NULL;
553
554 svc_rqst_release_pages(rqstp);
555 rqstp->rq_res.page_len = 0;
556 rqstp->rq_res.page_base = 0;
557
558 /* Reset response buffer and release
559 * the reservation.
560 * But first, check that enough space was reserved
561 * for the reply, otherwise we have a bug!
562 */
563 if ((rqstp->rq_res.len) > rqstp->rq_reserved)
564 printk(KERN_ERR "RPC request reserved %d but used %d\n",
565 rqstp->rq_reserved,
566 rqstp->rq_res.len);
567
568 rqstp->rq_res.head[0].iov_len = 0;
569 svc_reserve(rqstp, 0);
570 svc_xprt_release_slot(rqstp);
571 rqstp->rq_xprt = NULL;
572 svc_xprt_put(xprt);
573 }
574
575 /**
576 * svc_wake_up - Wake up a service thread for non-transport work
577 * @serv: RPC service
578 *
579 * Some svc_serv's will have occasional work to do, even when a xprt is not
580 * waiting to be serviced. This function is there to "kick" a task in one of
581 * those services so that it can wake up and do that work. Note that we only
582 * bother with pool 0 as we don't need to wake up more than one thread for
583 * this purpose.
584 */
svc_wake_up(struct svc_serv * serv)585 void svc_wake_up(struct svc_serv *serv)
586 {
587 struct svc_pool *pool = &serv->sv_pools[0];
588
589 set_bit(SP_TASK_PENDING, &pool->sp_flags);
590 svc_pool_wake_idle_thread(pool);
591 }
592 EXPORT_SYMBOL_GPL(svc_wake_up);
593
svc_port_is_privileged(struct sockaddr * sin)594 int svc_port_is_privileged(struct sockaddr *sin)
595 {
596 switch (sin->sa_family) {
597 case AF_INET:
598 return ntohs(((struct sockaddr_in *)sin)->sin_port)
599 < PROT_SOCK;
600 case AF_INET6:
601 return ntohs(((struct sockaddr_in6 *)sin)->sin6_port)
602 < PROT_SOCK;
603 default:
604 return 0;
605 }
606 }
607
608 /*
609 * Make sure that we don't have too many active connections. If we have,
610 * something must be dropped. It's not clear what will happen if we allow
611 * "too many" connections, but when dealing with network-facing software,
612 * we have to code defensively. Here we do that by imposing hard limits.
613 *
614 * There's no point in trying to do random drop here for DoS
615 * prevention. The NFS clients does 1 reconnect in 15 seconds. An
616 * attacker can easily beat that.
617 *
618 * The only somewhat efficient mechanism would be if drop old
619 * connections from the same IP first. But right now we don't even
620 * record the client IP in svc_sock.
621 *
622 * single-threaded services that expect a lot of clients will probably
623 * need to set sv_maxconn to override the default value which is based
624 * on the number of threads
625 */
svc_check_conn_limits(struct svc_serv * serv)626 static void svc_check_conn_limits(struct svc_serv *serv)
627 {
628 unsigned int limit = serv->sv_maxconn ? serv->sv_maxconn :
629 (serv->sv_nrthreads+3) * 20;
630
631 if (serv->sv_tmpcnt > limit) {
632 struct svc_xprt *xprt = NULL;
633 spin_lock_bh(&serv->sv_lock);
634 if (!list_empty(&serv->sv_tempsocks)) {
635 /* Try to help the admin */
636 net_notice_ratelimited("%s: too many open connections, consider increasing the %s\n",
637 serv->sv_name, serv->sv_maxconn ?
638 "max number of connections" :
639 "number of threads");
640 /*
641 * Always select the oldest connection. It's not fair,
642 * but so is life
643 */
644 xprt = list_entry(serv->sv_tempsocks.prev,
645 struct svc_xprt,
646 xpt_list);
647 set_bit(XPT_CLOSE, &xprt->xpt_flags);
648 svc_xprt_get(xprt);
649 }
650 spin_unlock_bh(&serv->sv_lock);
651
652 if (xprt) {
653 svc_xprt_enqueue(xprt);
654 svc_xprt_put(xprt);
655 }
656 }
657 }
658
svc_alloc_arg(struct svc_rqst * rqstp)659 static bool svc_alloc_arg(struct svc_rqst *rqstp)
660 {
661 struct svc_serv *serv = rqstp->rq_server;
662 struct xdr_buf *arg = &rqstp->rq_arg;
663 unsigned long pages, filled, ret;
664
665 pages = (serv->sv_max_mesg + 2 * PAGE_SIZE) >> PAGE_SHIFT;
666 if (pages > RPCSVC_MAXPAGES) {
667 pr_warn_once("svc: warning: pages=%lu > RPCSVC_MAXPAGES=%lu\n",
668 pages, RPCSVC_MAXPAGES);
669 /* use as many pages as possible */
670 pages = RPCSVC_MAXPAGES;
671 }
672
673 for (filled = 0; filled < pages; filled = ret) {
674 ret = alloc_pages_bulk_array(GFP_KERNEL, pages,
675 rqstp->rq_pages);
676 if (ret > filled)
677 /* Made progress, don't sleep yet */
678 continue;
679
680 set_current_state(TASK_IDLE);
681 if (svc_thread_should_stop(rqstp)) {
682 set_current_state(TASK_RUNNING);
683 return false;
684 }
685 trace_svc_alloc_arg_err(pages, ret);
686 memalloc_retry_wait(GFP_KERNEL);
687 }
688 rqstp->rq_page_end = &rqstp->rq_pages[pages];
689 rqstp->rq_pages[pages] = NULL; /* this might be seen in nfsd_splice_actor() */
690
691 /* Make arg->head point to first page and arg->pages point to rest */
692 arg->head[0].iov_base = page_address(rqstp->rq_pages[0]);
693 arg->head[0].iov_len = PAGE_SIZE;
694 arg->pages = rqstp->rq_pages + 1;
695 arg->page_base = 0;
696 /* save at least one page for response */
697 arg->page_len = (pages-2)*PAGE_SIZE;
698 arg->len = (pages-1)*PAGE_SIZE;
699 arg->tail[0].iov_len = 0;
700
701 rqstp->rq_xid = xdr_zero;
702 return true;
703 }
704
705 static bool
svc_thread_should_sleep(struct svc_rqst * rqstp)706 svc_thread_should_sleep(struct svc_rqst *rqstp)
707 {
708 struct svc_pool *pool = rqstp->rq_pool;
709
710 /* did someone call svc_wake_up? */
711 if (test_bit(SP_TASK_PENDING, &pool->sp_flags))
712 return false;
713
714 /* was a socket queued? */
715 if (!lwq_empty(&pool->sp_xprts))
716 return false;
717
718 /* are we shutting down? */
719 if (svc_thread_should_stop(rqstp))
720 return false;
721
722 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
723 if (svc_is_backchannel(rqstp)) {
724 if (!lwq_empty(&rqstp->rq_server->sv_cb_list))
725 return false;
726 }
727 #endif
728
729 return true;
730 }
731
svc_thread_wait_for_work(struct svc_rqst * rqstp)732 static void svc_thread_wait_for_work(struct svc_rqst *rqstp)
733 {
734 struct svc_pool *pool = rqstp->rq_pool;
735
736 if (svc_thread_should_sleep(rqstp)) {
737 set_current_state(TASK_IDLE | TASK_FREEZABLE);
738 llist_add(&rqstp->rq_idle, &pool->sp_idle_threads);
739 if (likely(svc_thread_should_sleep(rqstp)))
740 schedule();
741
742 while (!llist_del_first_this(&pool->sp_idle_threads,
743 &rqstp->rq_idle)) {
744 /* Work just became available. This thread can only
745 * handle it after removing rqstp from the idle
746 * list. If that attempt failed, some other thread
747 * must have queued itself after finding no
748 * work to do, so that thread has taken responsibly
749 * for this new work. This thread can safely sleep
750 * until woken again.
751 */
752 schedule();
753 set_current_state(TASK_IDLE | TASK_FREEZABLE);
754 }
755 __set_current_state(TASK_RUNNING);
756 } else {
757 cond_resched();
758 }
759 try_to_freeze();
760 }
761
svc_add_new_temp_xprt(struct svc_serv * serv,struct svc_xprt * newxpt)762 static void svc_add_new_temp_xprt(struct svc_serv *serv, struct svc_xprt *newxpt)
763 {
764 spin_lock_bh(&serv->sv_lock);
765 set_bit(XPT_TEMP, &newxpt->xpt_flags);
766 list_add(&newxpt->xpt_list, &serv->sv_tempsocks);
767 serv->sv_tmpcnt++;
768 if (serv->sv_temptimer.function == NULL) {
769 /* setup timer to age temp transports */
770 serv->sv_temptimer.function = svc_age_temp_xprts;
771 mod_timer(&serv->sv_temptimer,
772 jiffies + svc_conn_age_period * HZ);
773 }
774 spin_unlock_bh(&serv->sv_lock);
775 svc_xprt_received(newxpt);
776 }
777
svc_handle_xprt(struct svc_rqst * rqstp,struct svc_xprt * xprt)778 static void svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
779 {
780 struct svc_serv *serv = rqstp->rq_server;
781 int len = 0;
782
783 if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) {
784 if (test_and_clear_bit(XPT_KILL_TEMP, &xprt->xpt_flags))
785 xprt->xpt_ops->xpo_kill_temp_xprt(xprt);
786 svc_delete_xprt(xprt);
787 /* Leave XPT_BUSY set on the dead xprt: */
788 goto out;
789 }
790 if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) {
791 struct svc_xprt *newxpt;
792 /*
793 * We know this module_get will succeed because the
794 * listener holds a reference too
795 */
796 __module_get(xprt->xpt_class->xcl_owner);
797 svc_check_conn_limits(xprt->xpt_server);
798 newxpt = xprt->xpt_ops->xpo_accept(xprt);
799 if (newxpt) {
800 newxpt->xpt_cred = get_cred(xprt->xpt_cred);
801 svc_add_new_temp_xprt(serv, newxpt);
802 trace_svc_xprt_accept(newxpt, serv->sv_name);
803 } else {
804 module_put(xprt->xpt_class->xcl_owner);
805 }
806 svc_xprt_received(xprt);
807 } else if (test_bit(XPT_HANDSHAKE, &xprt->xpt_flags)) {
808 xprt->xpt_ops->xpo_handshake(xprt);
809 svc_xprt_received(xprt);
810 } else if (svc_xprt_reserve_slot(rqstp, xprt)) {
811 /* XPT_DATA|XPT_DEFERRED case: */
812 rqstp->rq_deferred = svc_deferred_dequeue(xprt);
813 if (rqstp->rq_deferred)
814 len = svc_deferred_recv(rqstp);
815 else
816 len = xprt->xpt_ops->xpo_recvfrom(rqstp);
817 rqstp->rq_reserved = serv->sv_max_mesg;
818 atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
819 if (len <= 0)
820 goto out;
821
822 trace_svc_xdr_recvfrom(&rqstp->rq_arg);
823
824 clear_bit(XPT_OLD, &xprt->xpt_flags);
825
826 rqstp->rq_chandle.defer = svc_defer;
827
828 if (serv->sv_stats)
829 serv->sv_stats->netcnt++;
830 percpu_counter_inc(&rqstp->rq_pool->sp_messages_arrived);
831 rqstp->rq_stime = ktime_get();
832 svc_process(rqstp);
833 } else
834 svc_xprt_received(xprt);
835
836 out:
837 rqstp->rq_res.len = 0;
838 svc_xprt_release(rqstp);
839 }
840
svc_thread_wake_next(struct svc_rqst * rqstp)841 static void svc_thread_wake_next(struct svc_rqst *rqstp)
842 {
843 if (!svc_thread_should_sleep(rqstp))
844 /* More work pending after I dequeued some,
845 * wake another worker
846 */
847 svc_pool_wake_idle_thread(rqstp->rq_pool);
848 }
849
850 /**
851 * svc_recv - Receive and process the next request on any transport
852 * @rqstp: an idle RPC service thread
853 *
854 * This code is carefully organised not to touch any cachelines in
855 * the shared svc_serv structure, only cachelines in the local
856 * svc_pool.
857 */
svc_recv(struct svc_rqst * rqstp)858 void svc_recv(struct svc_rqst *rqstp)
859 {
860 struct svc_pool *pool = rqstp->rq_pool;
861
862 if (!svc_alloc_arg(rqstp))
863 return;
864
865 svc_thread_wait_for_work(rqstp);
866
867 clear_bit(SP_TASK_PENDING, &pool->sp_flags);
868
869 if (svc_thread_should_stop(rqstp)) {
870 svc_thread_wake_next(rqstp);
871 return;
872 }
873
874 rqstp->rq_xprt = svc_xprt_dequeue(pool);
875 if (rqstp->rq_xprt) {
876 struct svc_xprt *xprt = rqstp->rq_xprt;
877
878 svc_thread_wake_next(rqstp);
879 /* Normally we will wait up to 5 seconds for any required
880 * cache information to be provided. When there are no
881 * idle threads, we reduce the wait time.
882 */
883 if (pool->sp_idle_threads.first)
884 rqstp->rq_chandle.thread_wait = 5 * HZ;
885 else
886 rqstp->rq_chandle.thread_wait = 1 * HZ;
887
888 trace_svc_xprt_dequeue(rqstp);
889 svc_handle_xprt(rqstp, xprt);
890 }
891
892 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
893 if (svc_is_backchannel(rqstp)) {
894 struct svc_serv *serv = rqstp->rq_server;
895 struct rpc_rqst *req;
896
897 req = lwq_dequeue(&serv->sv_cb_list,
898 struct rpc_rqst, rq_bc_list);
899 if (req) {
900 svc_thread_wake_next(rqstp);
901 svc_process_bc(req, rqstp);
902 }
903 }
904 #endif
905 }
906 EXPORT_SYMBOL_GPL(svc_recv);
907
908 /*
909 * Drop request
910 */
svc_drop(struct svc_rqst * rqstp)911 void svc_drop(struct svc_rqst *rqstp)
912 {
913 trace_svc_drop(rqstp);
914 }
915 EXPORT_SYMBOL_GPL(svc_drop);
916
917 /**
918 * svc_send - Return reply to client
919 * @rqstp: RPC transaction context
920 *
921 */
svc_send(struct svc_rqst * rqstp)922 void svc_send(struct svc_rqst *rqstp)
923 {
924 struct svc_xprt *xprt;
925 struct xdr_buf *xb;
926 int status;
927
928 xprt = rqstp->rq_xprt;
929
930 /* calculate over-all length */
931 xb = &rqstp->rq_res;
932 xb->len = xb->head[0].iov_len +
933 xb->page_len +
934 xb->tail[0].iov_len;
935 trace_svc_xdr_sendto(rqstp->rq_xid, xb);
936 trace_svc_stats_latency(rqstp);
937
938 status = xprt->xpt_ops->xpo_sendto(rqstp);
939
940 trace_svc_send(rqstp, status);
941 }
942
943 /*
944 * Timer function to close old temporary transports, using
945 * a mark-and-sweep algorithm.
946 */
svc_age_temp_xprts(struct timer_list * t)947 static void svc_age_temp_xprts(struct timer_list *t)
948 {
949 struct svc_serv *serv = from_timer(serv, t, sv_temptimer);
950 struct svc_xprt *xprt;
951 struct list_head *le, *next;
952
953 dprintk("svc_age_temp_xprts\n");
954
955 if (!spin_trylock_bh(&serv->sv_lock)) {
956 /* busy, try again 1 sec later */
957 dprintk("svc_age_temp_xprts: busy\n");
958 mod_timer(&serv->sv_temptimer, jiffies + HZ);
959 return;
960 }
961
962 list_for_each_safe(le, next, &serv->sv_tempsocks) {
963 xprt = list_entry(le, struct svc_xprt, xpt_list);
964
965 /* First time through, just mark it OLD. Second time
966 * through, close it. */
967 if (!test_and_set_bit(XPT_OLD, &xprt->xpt_flags))
968 continue;
969 if (kref_read(&xprt->xpt_ref) > 1 ||
970 test_bit(XPT_BUSY, &xprt->xpt_flags))
971 continue;
972 list_del_init(le);
973 set_bit(XPT_CLOSE, &xprt->xpt_flags);
974 dprintk("queuing xprt %p for closing\n", xprt);
975
976 /* a thread will dequeue and close it soon */
977 svc_xprt_enqueue(xprt);
978 }
979 spin_unlock_bh(&serv->sv_lock);
980
981 mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ);
982 }
983
984 /* Close temporary transports whose xpt_local matches server_addr immediately
985 * instead of waiting for them to be picked up by the timer.
986 *
987 * This is meant to be called from a notifier_block that runs when an ip
988 * address is deleted.
989 */
svc_age_temp_xprts_now(struct svc_serv * serv,struct sockaddr * server_addr)990 void svc_age_temp_xprts_now(struct svc_serv *serv, struct sockaddr *server_addr)
991 {
992 struct svc_xprt *xprt;
993 struct list_head *le, *next;
994 LIST_HEAD(to_be_closed);
995
996 spin_lock_bh(&serv->sv_lock);
997 list_for_each_safe(le, next, &serv->sv_tempsocks) {
998 xprt = list_entry(le, struct svc_xprt, xpt_list);
999 if (rpc_cmp_addr(server_addr, (struct sockaddr *)
1000 &xprt->xpt_local)) {
1001 dprintk("svc_age_temp_xprts_now: found %p\n", xprt);
1002 list_move(le, &to_be_closed);
1003 }
1004 }
1005 spin_unlock_bh(&serv->sv_lock);
1006
1007 while (!list_empty(&to_be_closed)) {
1008 le = to_be_closed.next;
1009 list_del_init(le);
1010 xprt = list_entry(le, struct svc_xprt, xpt_list);
1011 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1012 set_bit(XPT_KILL_TEMP, &xprt->xpt_flags);
1013 dprintk("svc_age_temp_xprts_now: queuing xprt %p for closing\n",
1014 xprt);
1015 svc_xprt_enqueue(xprt);
1016 }
1017 }
1018 EXPORT_SYMBOL_GPL(svc_age_temp_xprts_now);
1019
call_xpt_users(struct svc_xprt * xprt)1020 static void call_xpt_users(struct svc_xprt *xprt)
1021 {
1022 struct svc_xpt_user *u;
1023
1024 spin_lock(&xprt->xpt_lock);
1025 while (!list_empty(&xprt->xpt_users)) {
1026 u = list_first_entry(&xprt->xpt_users, struct svc_xpt_user, list);
1027 list_del_init(&u->list);
1028 u->callback(u);
1029 }
1030 spin_unlock(&xprt->xpt_lock);
1031 }
1032
1033 /*
1034 * Remove a dead transport
1035 */
svc_delete_xprt(struct svc_xprt * xprt)1036 static void svc_delete_xprt(struct svc_xprt *xprt)
1037 {
1038 struct svc_serv *serv = xprt->xpt_server;
1039 struct svc_deferred_req *dr;
1040
1041 if (test_and_set_bit(XPT_DEAD, &xprt->xpt_flags))
1042 return;
1043
1044 trace_svc_xprt_detach(xprt);
1045 xprt->xpt_ops->xpo_detach(xprt);
1046 if (xprt->xpt_bc_xprt)
1047 xprt->xpt_bc_xprt->ops->close(xprt->xpt_bc_xprt);
1048
1049 spin_lock_bh(&serv->sv_lock);
1050 list_del_init(&xprt->xpt_list);
1051 if (test_bit(XPT_TEMP, &xprt->xpt_flags))
1052 serv->sv_tmpcnt--;
1053 spin_unlock_bh(&serv->sv_lock);
1054
1055 while ((dr = svc_deferred_dequeue(xprt)) != NULL)
1056 free_deferred(xprt, dr);
1057
1058 call_xpt_users(xprt);
1059 svc_xprt_put(xprt);
1060 }
1061
1062 /**
1063 * svc_xprt_close - Close a client connection
1064 * @xprt: transport to disconnect
1065 *
1066 */
svc_xprt_close(struct svc_xprt * xprt)1067 void svc_xprt_close(struct svc_xprt *xprt)
1068 {
1069 trace_svc_xprt_close(xprt);
1070 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1071 if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
1072 /* someone else will have to effect the close */
1073 return;
1074 /*
1075 * We expect svc_close_xprt() to work even when no threads are
1076 * running (e.g., while configuring the server before starting
1077 * any threads), so if the transport isn't busy, we delete
1078 * it ourself:
1079 */
1080 svc_delete_xprt(xprt);
1081 }
1082 EXPORT_SYMBOL_GPL(svc_xprt_close);
1083
svc_close_list(struct svc_serv * serv,struct list_head * xprt_list,struct net * net)1084 static int svc_close_list(struct svc_serv *serv, struct list_head *xprt_list, struct net *net)
1085 {
1086 struct svc_xprt *xprt;
1087 int ret = 0;
1088
1089 spin_lock_bh(&serv->sv_lock);
1090 list_for_each_entry(xprt, xprt_list, xpt_list) {
1091 if (xprt->xpt_net != net)
1092 continue;
1093 ret++;
1094 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1095 svc_xprt_enqueue(xprt);
1096 }
1097 spin_unlock_bh(&serv->sv_lock);
1098 return ret;
1099 }
1100
svc_clean_up_xprts(struct svc_serv * serv,struct net * net)1101 static void svc_clean_up_xprts(struct svc_serv *serv, struct net *net)
1102 {
1103 struct svc_xprt *xprt;
1104 int i;
1105
1106 for (i = 0; i < serv->sv_nrpools; i++) {
1107 struct svc_pool *pool = &serv->sv_pools[i];
1108 struct llist_node *q, **t1, *t2;
1109
1110 q = lwq_dequeue_all(&pool->sp_xprts);
1111 lwq_for_each_safe(xprt, t1, t2, &q, xpt_ready) {
1112 if (xprt->xpt_net == net) {
1113 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1114 svc_delete_xprt(xprt);
1115 xprt = NULL;
1116 }
1117 }
1118
1119 if (q)
1120 lwq_enqueue_batch(q, &pool->sp_xprts);
1121 }
1122 }
1123
1124 /**
1125 * svc_xprt_destroy_all - Destroy transports associated with @serv
1126 * @serv: RPC service to be shut down
1127 * @net: target network namespace
1128 *
1129 * Server threads may still be running (especially in the case where the
1130 * service is still running in other network namespaces).
1131 *
1132 * So we shut down sockets the same way we would on a running server, by
1133 * setting XPT_CLOSE, enqueuing, and letting a thread pick it up to do
1134 * the close. In the case there are no such other threads,
1135 * threads running, svc_clean_up_xprts() does a simple version of a
1136 * server's main event loop, and in the case where there are other
1137 * threads, we may need to wait a little while and then check again to
1138 * see if they're done.
1139 */
svc_xprt_destroy_all(struct svc_serv * serv,struct net * net)1140 void svc_xprt_destroy_all(struct svc_serv *serv, struct net *net)
1141 {
1142 int delay = 0;
1143
1144 while (svc_close_list(serv, &serv->sv_permsocks, net) +
1145 svc_close_list(serv, &serv->sv_tempsocks, net)) {
1146
1147 svc_clean_up_xprts(serv, net);
1148 msleep(delay++);
1149 }
1150 }
1151 EXPORT_SYMBOL_GPL(svc_xprt_destroy_all);
1152
1153 /*
1154 * Handle defer and revisit of requests
1155 */
1156
svc_revisit(struct cache_deferred_req * dreq,int too_many)1157 static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
1158 {
1159 struct svc_deferred_req *dr =
1160 container_of(dreq, struct svc_deferred_req, handle);
1161 struct svc_xprt *xprt = dr->xprt;
1162
1163 spin_lock(&xprt->xpt_lock);
1164 set_bit(XPT_DEFERRED, &xprt->xpt_flags);
1165 if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) {
1166 spin_unlock(&xprt->xpt_lock);
1167 trace_svc_defer_drop(dr);
1168 free_deferred(xprt, dr);
1169 svc_xprt_put(xprt);
1170 return;
1171 }
1172 dr->xprt = NULL;
1173 list_add(&dr->handle.recent, &xprt->xpt_deferred);
1174 spin_unlock(&xprt->xpt_lock);
1175 trace_svc_defer_queue(dr);
1176 svc_xprt_enqueue(xprt);
1177 svc_xprt_put(xprt);
1178 }
1179
1180 /*
1181 * Save the request off for later processing. The request buffer looks
1182 * like this:
1183 *
1184 * <xprt-header><rpc-header><rpc-pagelist><rpc-tail>
1185 *
1186 * This code can only handle requests that consist of an xprt-header
1187 * and rpc-header.
1188 */
svc_defer(struct cache_req * req)1189 static struct cache_deferred_req *svc_defer(struct cache_req *req)
1190 {
1191 struct svc_rqst *rqstp = container_of(req, struct svc_rqst, rq_chandle);
1192 struct svc_deferred_req *dr;
1193
1194 if (rqstp->rq_arg.page_len || !test_bit(RQ_USEDEFERRAL, &rqstp->rq_flags))
1195 return NULL; /* if more than a page, give up FIXME */
1196 if (rqstp->rq_deferred) {
1197 dr = rqstp->rq_deferred;
1198 rqstp->rq_deferred = NULL;
1199 } else {
1200 size_t skip;
1201 size_t size;
1202 /* FIXME maybe discard if size too large */
1203 size = sizeof(struct svc_deferred_req) + rqstp->rq_arg.len;
1204 dr = kmalloc(size, GFP_KERNEL);
1205 if (dr == NULL)
1206 return NULL;
1207
1208 dr->handle.owner = rqstp->rq_server;
1209 dr->prot = rqstp->rq_prot;
1210 memcpy(&dr->addr, &rqstp->rq_addr, rqstp->rq_addrlen);
1211 dr->addrlen = rqstp->rq_addrlen;
1212 dr->daddr = rqstp->rq_daddr;
1213 dr->argslen = rqstp->rq_arg.len >> 2;
1214
1215 /* back up head to the start of the buffer and copy */
1216 skip = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len;
1217 memcpy(dr->args, rqstp->rq_arg.head[0].iov_base - skip,
1218 dr->argslen << 2);
1219 }
1220 dr->xprt_ctxt = rqstp->rq_xprt_ctxt;
1221 rqstp->rq_xprt_ctxt = NULL;
1222 trace_svc_defer(rqstp);
1223 svc_xprt_get(rqstp->rq_xprt);
1224 dr->xprt = rqstp->rq_xprt;
1225 set_bit(RQ_DROPME, &rqstp->rq_flags);
1226
1227 dr->handle.revisit = svc_revisit;
1228 return &dr->handle;
1229 }
1230
1231 /*
1232 * recv data from a deferred request into an active one
1233 */
svc_deferred_recv(struct svc_rqst * rqstp)1234 static noinline int svc_deferred_recv(struct svc_rqst *rqstp)
1235 {
1236 struct svc_deferred_req *dr = rqstp->rq_deferred;
1237
1238 trace_svc_defer_recv(dr);
1239
1240 /* setup iov_base past transport header */
1241 rqstp->rq_arg.head[0].iov_base = dr->args;
1242 /* The iov_len does not include the transport header bytes */
1243 rqstp->rq_arg.head[0].iov_len = dr->argslen << 2;
1244 rqstp->rq_arg.page_len = 0;
1245 /* The rq_arg.len includes the transport header bytes */
1246 rqstp->rq_arg.len = dr->argslen << 2;
1247 rqstp->rq_prot = dr->prot;
1248 memcpy(&rqstp->rq_addr, &dr->addr, dr->addrlen);
1249 rqstp->rq_addrlen = dr->addrlen;
1250 /* Save off transport header len in case we get deferred again */
1251 rqstp->rq_daddr = dr->daddr;
1252 rqstp->rq_respages = rqstp->rq_pages;
1253 rqstp->rq_xprt_ctxt = dr->xprt_ctxt;
1254
1255 dr->xprt_ctxt = NULL;
1256 svc_xprt_received(rqstp->rq_xprt);
1257 return dr->argslen << 2;
1258 }
1259
1260
svc_deferred_dequeue(struct svc_xprt * xprt)1261 static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt)
1262 {
1263 struct svc_deferred_req *dr = NULL;
1264
1265 if (!test_bit(XPT_DEFERRED, &xprt->xpt_flags))
1266 return NULL;
1267 spin_lock(&xprt->xpt_lock);
1268 if (!list_empty(&xprt->xpt_deferred)) {
1269 dr = list_entry(xprt->xpt_deferred.next,
1270 struct svc_deferred_req,
1271 handle.recent);
1272 list_del_init(&dr->handle.recent);
1273 } else
1274 clear_bit(XPT_DEFERRED, &xprt->xpt_flags);
1275 spin_unlock(&xprt->xpt_lock);
1276 return dr;
1277 }
1278
1279 /**
1280 * svc_find_listener - find an RPC transport instance
1281 * @serv: pointer to svc_serv to search
1282 * @xcl_name: C string containing transport's class name
1283 * @net: owner net pointer
1284 * @sa: sockaddr containing address
1285 *
1286 * Return the transport instance pointer for the endpoint accepting
1287 * connections/peer traffic from the specified transport class,
1288 * and matching sockaddr.
1289 */
svc_find_listener(struct svc_serv * serv,const char * xcl_name,struct net * net,const struct sockaddr * sa)1290 struct svc_xprt *svc_find_listener(struct svc_serv *serv, const char *xcl_name,
1291 struct net *net, const struct sockaddr *sa)
1292 {
1293 struct svc_xprt *xprt;
1294 struct svc_xprt *found = NULL;
1295
1296 spin_lock_bh(&serv->sv_lock);
1297 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1298 if (xprt->xpt_net != net)
1299 continue;
1300 if (strcmp(xprt->xpt_class->xcl_name, xcl_name))
1301 continue;
1302 if (!rpc_cmp_addr_port(sa, (struct sockaddr *)&xprt->xpt_local))
1303 continue;
1304 found = xprt;
1305 svc_xprt_get(xprt);
1306 break;
1307 }
1308 spin_unlock_bh(&serv->sv_lock);
1309 return found;
1310 }
1311 EXPORT_SYMBOL_GPL(svc_find_listener);
1312
1313 /**
1314 * svc_find_xprt - find an RPC transport instance
1315 * @serv: pointer to svc_serv to search
1316 * @xcl_name: C string containing transport's class name
1317 * @net: owner net pointer
1318 * @af: Address family of transport's local address
1319 * @port: transport's IP port number
1320 *
1321 * Return the transport instance pointer for the endpoint accepting
1322 * connections/peer traffic from the specified transport class,
1323 * address family and port.
1324 *
1325 * Specifying 0 for the address family or port is effectively a
1326 * wild-card, and will result in matching the first transport in the
1327 * service's list that has a matching class name.
1328 */
svc_find_xprt(struct svc_serv * serv,const char * xcl_name,struct net * net,const sa_family_t af,const unsigned short port)1329 struct svc_xprt *svc_find_xprt(struct svc_serv *serv, const char *xcl_name,
1330 struct net *net, const sa_family_t af,
1331 const unsigned short port)
1332 {
1333 struct svc_xprt *xprt;
1334 struct svc_xprt *found = NULL;
1335
1336 /* Sanity check the args */
1337 if (serv == NULL || xcl_name == NULL)
1338 return found;
1339
1340 spin_lock_bh(&serv->sv_lock);
1341 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1342 if (xprt->xpt_net != net)
1343 continue;
1344 if (strcmp(xprt->xpt_class->xcl_name, xcl_name))
1345 continue;
1346 if (af != AF_UNSPEC && af != xprt->xpt_local.ss_family)
1347 continue;
1348 if (port != 0 && port != svc_xprt_local_port(xprt))
1349 continue;
1350 found = xprt;
1351 svc_xprt_get(xprt);
1352 break;
1353 }
1354 spin_unlock_bh(&serv->sv_lock);
1355 return found;
1356 }
1357 EXPORT_SYMBOL_GPL(svc_find_xprt);
1358
svc_one_xprt_name(const struct svc_xprt * xprt,char * pos,int remaining)1359 static int svc_one_xprt_name(const struct svc_xprt *xprt,
1360 char *pos, int remaining)
1361 {
1362 int len;
1363
1364 len = snprintf(pos, remaining, "%s %u\n",
1365 xprt->xpt_class->xcl_name,
1366 svc_xprt_local_port(xprt));
1367 if (len >= remaining)
1368 return -ENAMETOOLONG;
1369 return len;
1370 }
1371
1372 /**
1373 * svc_xprt_names - format a buffer with a list of transport names
1374 * @serv: pointer to an RPC service
1375 * @buf: pointer to a buffer to be filled in
1376 * @buflen: length of buffer to be filled in
1377 *
1378 * Fills in @buf with a string containing a list of transport names,
1379 * each name terminated with '\n'.
1380 *
1381 * Returns positive length of the filled-in string on success; otherwise
1382 * a negative errno value is returned if an error occurs.
1383 */
svc_xprt_names(struct svc_serv * serv,char * buf,const int buflen)1384 int svc_xprt_names(struct svc_serv *serv, char *buf, const int buflen)
1385 {
1386 struct svc_xprt *xprt;
1387 int len, totlen;
1388 char *pos;
1389
1390 /* Sanity check args */
1391 if (!serv)
1392 return 0;
1393
1394 spin_lock_bh(&serv->sv_lock);
1395
1396 pos = buf;
1397 totlen = 0;
1398 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1399 len = svc_one_xprt_name(xprt, pos, buflen - totlen);
1400 if (len < 0) {
1401 *buf = '\0';
1402 totlen = len;
1403 }
1404 if (len <= 0)
1405 break;
1406
1407 pos += len;
1408 totlen += len;
1409 }
1410
1411 spin_unlock_bh(&serv->sv_lock);
1412 return totlen;
1413 }
1414 EXPORT_SYMBOL_GPL(svc_xprt_names);
1415
1416 /*----------------------------------------------------------------------------*/
1417
svc_pool_stats_start(struct seq_file * m,loff_t * pos)1418 static void *svc_pool_stats_start(struct seq_file *m, loff_t *pos)
1419 {
1420 unsigned int pidx = (unsigned int)*pos;
1421 struct svc_info *si = m->private;
1422
1423 dprintk("svc_pool_stats_start, *pidx=%u\n", pidx);
1424
1425 mutex_lock(si->mutex);
1426
1427 if (!pidx)
1428 return SEQ_START_TOKEN;
1429 if (!si->serv)
1430 return NULL;
1431 return pidx > si->serv->sv_nrpools ? NULL
1432 : &si->serv->sv_pools[pidx - 1];
1433 }
1434
svc_pool_stats_next(struct seq_file * m,void * p,loff_t * pos)1435 static void *svc_pool_stats_next(struct seq_file *m, void *p, loff_t *pos)
1436 {
1437 struct svc_pool *pool = p;
1438 struct svc_info *si = m->private;
1439 struct svc_serv *serv = si->serv;
1440
1441 dprintk("svc_pool_stats_next, *pos=%llu\n", *pos);
1442
1443 if (!serv) {
1444 pool = NULL;
1445 } else if (p == SEQ_START_TOKEN) {
1446 pool = &serv->sv_pools[0];
1447 } else {
1448 unsigned int pidx = (pool - &serv->sv_pools[0]);
1449 if (pidx < serv->sv_nrpools-1)
1450 pool = &serv->sv_pools[pidx+1];
1451 else
1452 pool = NULL;
1453 }
1454 ++*pos;
1455 return pool;
1456 }
1457
svc_pool_stats_stop(struct seq_file * m,void * p)1458 static void svc_pool_stats_stop(struct seq_file *m, void *p)
1459 {
1460 struct svc_info *si = m->private;
1461
1462 mutex_unlock(si->mutex);
1463 }
1464
svc_pool_stats_show(struct seq_file * m,void * p)1465 static int svc_pool_stats_show(struct seq_file *m, void *p)
1466 {
1467 struct svc_pool *pool = p;
1468
1469 if (p == SEQ_START_TOKEN) {
1470 seq_puts(m, "# pool packets-arrived sockets-enqueued threads-woken threads-timedout\n");
1471 return 0;
1472 }
1473
1474 seq_printf(m, "%u %llu %llu %llu 0\n",
1475 pool->sp_id,
1476 percpu_counter_sum_positive(&pool->sp_messages_arrived),
1477 percpu_counter_sum_positive(&pool->sp_sockets_queued),
1478 percpu_counter_sum_positive(&pool->sp_threads_woken));
1479
1480 return 0;
1481 }
1482
1483 static const struct seq_operations svc_pool_stats_seq_ops = {
1484 .start = svc_pool_stats_start,
1485 .next = svc_pool_stats_next,
1486 .stop = svc_pool_stats_stop,
1487 .show = svc_pool_stats_show,
1488 };
1489
svc_pool_stats_open(struct svc_info * info,struct file * file)1490 int svc_pool_stats_open(struct svc_info *info, struct file *file)
1491 {
1492 struct seq_file *seq;
1493 int err;
1494
1495 err = seq_open(file, &svc_pool_stats_seq_ops);
1496 if (err)
1497 return err;
1498 seq = file->private_data;
1499 seq->private = info;
1500
1501 return 0;
1502 }
1503 EXPORT_SYMBOL(svc_pool_stats_open);
1504
1505 /*----------------------------------------------------------------------------*/
1506