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