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TOMOYO Linux Cross Reference
Linux/net/sunrpc/svc_xprt.c

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  1 /*
  2  * linux/net/sunrpc/svc_xprt.c
  3  *
  4  * Author: Tom Tucker <tom@opengridcomputing.com>
  5  */
  6 
  7 #include <linux/sched.h>
  8 #include <linux/errno.h>
  9 #include <linux/freezer.h>
 10 #include <linux/kthread.h>
 11 #include <linux/slab.h>
 12 #include <net/sock.h>
 13 #include <linux/sunrpc/addr.h>
 14 #include <linux/sunrpc/stats.h>
 15 #include <linux/sunrpc/svc_xprt.h>
 16 #include <linux/sunrpc/svcsock.h>
 17 #include <linux/sunrpc/xprt.h>
 18 #include <linux/module.h>
 19 #include <linux/netdevice.h>
 20 #include <trace/events/sunrpc.h>
 21 
 22 #define RPCDBG_FACILITY RPCDBG_SVCXPRT
 23 
 24 static unsigned int svc_rpc_per_connection_limit __read_mostly;
 25 module_param(svc_rpc_per_connection_limit, uint, 0644);
 26 
 27 
 28 static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt);
 29 static int svc_deferred_recv(struct svc_rqst *rqstp);
 30 static struct cache_deferred_req *svc_defer(struct cache_req *req);
 31 static void svc_age_temp_xprts(struct timer_list *t);
 32 static void svc_delete_xprt(struct svc_xprt *xprt);
 33 
 34 /* apparently the "standard" is that clients close
 35  * idle connections after 5 minutes, servers after
 36  * 6 minutes
 37  *   http://www.connectathon.org/talks96/nfstcp.pdf
 38  */
 39 static int svc_conn_age_period = 6*60;
 40 
 41 /* List of registered transport classes */
 42 static DEFINE_SPINLOCK(svc_xprt_class_lock);
 43 static LIST_HEAD(svc_xprt_class_list);
 44 
 45 /* SMP locking strategy:
 46  *
 47  *      svc_pool->sp_lock protects most of the fields of that pool.
 48  *      svc_serv->sv_lock protects sv_tempsocks, sv_permsocks, sv_tmpcnt.
 49  *      when both need to be taken (rare), svc_serv->sv_lock is first.
 50  *      The "service mutex" protects svc_serv->sv_nrthread.
 51  *      svc_sock->sk_lock protects the svc_sock->sk_deferred list
 52  *             and the ->sk_info_authunix cache.
 53  *
 54  *      The XPT_BUSY bit in xprt->xpt_flags prevents a transport being
 55  *      enqueued multiply. During normal transport processing this bit
 56  *      is set by svc_xprt_enqueue and cleared by svc_xprt_received.
 57  *      Providers should not manipulate this bit directly.
 58  *
 59  *      Some flags can be set to certain values at any time
 60  *      providing that certain rules are followed:
 61  *
 62  *      XPT_CONN, XPT_DATA:
 63  *              - Can be set or cleared at any time.
 64  *              - After a set, svc_xprt_enqueue must be called to enqueue
 65  *                the transport for processing.
 66  *              - After a clear, the transport must be read/accepted.
 67  *                If this succeeds, it must be set again.
 68  *      XPT_CLOSE:
 69  *              - Can set at any time. It is never cleared.
 70  *      XPT_DEAD:
 71  *              - Can only be set while XPT_BUSY is held which ensures
 72  *                that no other thread will be using the transport or will
 73  *                try to set XPT_DEAD.
 74  */
 75 int svc_reg_xprt_class(struct svc_xprt_class *xcl)
 76 {
 77         struct svc_xprt_class *cl;
 78         int res = -EEXIST;
 79 
 80         dprintk("svc: Adding svc transport class '%s'\n", xcl->xcl_name);
 81 
 82         INIT_LIST_HEAD(&xcl->xcl_list);
 83         spin_lock(&svc_xprt_class_lock);
 84         /* Make sure there isn't already a class with the same name */
 85         list_for_each_entry(cl, &svc_xprt_class_list, xcl_list) {
 86                 if (strcmp(xcl->xcl_name, cl->xcl_name) == 0)
 87                         goto out;
 88         }
 89         list_add_tail(&xcl->xcl_list, &svc_xprt_class_list);
 90         res = 0;
 91 out:
 92         spin_unlock(&svc_xprt_class_lock);
 93         return res;
 94 }
 95 EXPORT_SYMBOL_GPL(svc_reg_xprt_class);
 96 
 97 void svc_unreg_xprt_class(struct svc_xprt_class *xcl)
 98 {
 99         dprintk("svc: Removing svc transport class '%s'\n", xcl->xcl_name);
100         spin_lock(&svc_xprt_class_lock);
101         list_del_init(&xcl->xcl_list);
102         spin_unlock(&svc_xprt_class_lock);
103 }
104 EXPORT_SYMBOL_GPL(svc_unreg_xprt_class);
105 
106 /*
107  * Format the transport list for printing
108  */
109 int svc_print_xprts(char *buf, int maxlen)
110 {
111         struct svc_xprt_class *xcl;
112         char tmpstr[80];
113         int len = 0;
114         buf[0] = '\0';
115 
116         spin_lock(&svc_xprt_class_lock);
117         list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
118                 int slen;
119 
120                 sprintf(tmpstr, "%s %d\n", xcl->xcl_name, xcl->xcl_max_payload);
121                 slen = strlen(tmpstr);
122                 if (len + slen > maxlen)
123                         break;
124                 len += slen;
125                 strcat(buf, tmpstr);
126         }
127         spin_unlock(&svc_xprt_class_lock);
128 
129         return len;
130 }
131 
132 static void svc_xprt_free(struct kref *kref)
133 {
134         struct svc_xprt *xprt =
135                 container_of(kref, struct svc_xprt, xpt_ref);
136         struct module *owner = xprt->xpt_class->xcl_owner;
137         if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags))
138                 svcauth_unix_info_release(xprt);
139         put_net(xprt->xpt_net);
140         /* See comment on corresponding get in xs_setup_bc_tcp(): */
141         if (xprt->xpt_bc_xprt)
142                 xprt_put(xprt->xpt_bc_xprt);
143         if (xprt->xpt_bc_xps)
144                 xprt_switch_put(xprt->xpt_bc_xps);
145         xprt->xpt_ops->xpo_free(xprt);
146         module_put(owner);
147 }
148 
149 void svc_xprt_put(struct svc_xprt *xprt)
150 {
151         kref_put(&xprt->xpt_ref, svc_xprt_free);
152 }
153 EXPORT_SYMBOL_GPL(svc_xprt_put);
154 
155 /*
156  * Called by transport drivers to initialize the transport independent
157  * portion of the transport instance.
158  */
159 void svc_xprt_init(struct net *net, struct svc_xprt_class *xcl,
160                    struct svc_xprt *xprt, struct svc_serv *serv)
161 {
162         memset(xprt, 0, sizeof(*xprt));
163         xprt->xpt_class = xcl;
164         xprt->xpt_ops = xcl->xcl_ops;
165         kref_init(&xprt->xpt_ref);
166         xprt->xpt_server = serv;
167         INIT_LIST_HEAD(&xprt->xpt_list);
168         INIT_LIST_HEAD(&xprt->xpt_ready);
169         INIT_LIST_HEAD(&xprt->xpt_deferred);
170         INIT_LIST_HEAD(&xprt->xpt_users);
171         mutex_init(&xprt->xpt_mutex);
172         spin_lock_init(&xprt->xpt_lock);
173         set_bit(XPT_BUSY, &xprt->xpt_flags);
174         rpc_init_wait_queue(&xprt->xpt_bc_pending, "xpt_bc_pending");
175         xprt->xpt_net = get_net(net);
176         strcpy(xprt->xpt_remotebuf, "uninitialized");
177 }
178 EXPORT_SYMBOL_GPL(svc_xprt_init);
179 
180 static struct svc_xprt *__svc_xpo_create(struct svc_xprt_class *xcl,
181                                          struct svc_serv *serv,
182                                          struct net *net,
183                                          const int family,
184                                          const unsigned short port,
185                                          int flags)
186 {
187         struct sockaddr_in sin = {
188                 .sin_family             = AF_INET,
189                 .sin_addr.s_addr        = htonl(INADDR_ANY),
190                 .sin_port               = htons(port),
191         };
192 #if IS_ENABLED(CONFIG_IPV6)
193         struct sockaddr_in6 sin6 = {
194                 .sin6_family            = AF_INET6,
195                 .sin6_addr              = IN6ADDR_ANY_INIT,
196                 .sin6_port              = htons(port),
197         };
198 #endif
199         struct sockaddr *sap;
200         size_t len;
201 
202         switch (family) {
203         case PF_INET:
204                 sap = (struct sockaddr *)&sin;
205                 len = sizeof(sin);
206                 break;
207 #if IS_ENABLED(CONFIG_IPV6)
208         case PF_INET6:
209                 sap = (struct sockaddr *)&sin6;
210                 len = sizeof(sin6);
211                 break;
212 #endif
213         default:
214                 return ERR_PTR(-EAFNOSUPPORT);
215         }
216 
217         return xcl->xcl_ops->xpo_create(serv, net, sap, len, flags);
218 }
219 
220 /*
221  * svc_xprt_received conditionally queues the transport for processing
222  * by another thread. The caller must hold the XPT_BUSY bit and must
223  * not thereafter touch transport data.
224  *
225  * Note: XPT_DATA only gets cleared when a read-attempt finds no (or
226  * insufficient) data.
227  */
228 static void svc_xprt_received(struct svc_xprt *xprt)
229 {
230         if (!test_bit(XPT_BUSY, &xprt->xpt_flags)) {
231                 WARN_ONCE(1, "xprt=0x%p already busy!", xprt);
232                 return;
233         }
234 
235         /* As soon as we clear busy, the xprt could be closed and
236          * 'put', so we need a reference to call svc_enqueue_xprt with:
237          */
238         svc_xprt_get(xprt);
239         smp_mb__before_atomic();
240         clear_bit(XPT_BUSY, &xprt->xpt_flags);
241         xprt->xpt_server->sv_ops->svo_enqueue_xprt(xprt);
242         svc_xprt_put(xprt);
243 }
244 
245 void svc_add_new_perm_xprt(struct svc_serv *serv, struct svc_xprt *new)
246 {
247         clear_bit(XPT_TEMP, &new->xpt_flags);
248         spin_lock_bh(&serv->sv_lock);
249         list_add(&new->xpt_list, &serv->sv_permsocks);
250         spin_unlock_bh(&serv->sv_lock);
251         svc_xprt_received(new);
252 }
253 
254 static int _svc_create_xprt(struct svc_serv *serv, const char *xprt_name,
255                             struct net *net, const int family,
256                             const unsigned short port, int flags)
257 {
258         struct svc_xprt_class *xcl;
259 
260         spin_lock(&svc_xprt_class_lock);
261         list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
262                 struct svc_xprt *newxprt;
263                 unsigned short newport;
264 
265                 if (strcmp(xprt_name, xcl->xcl_name))
266                         continue;
267 
268                 if (!try_module_get(xcl->xcl_owner))
269                         goto err;
270 
271                 spin_unlock(&svc_xprt_class_lock);
272                 newxprt = __svc_xpo_create(xcl, serv, net, family, port, flags);
273                 if (IS_ERR(newxprt)) {
274                         module_put(xcl->xcl_owner);
275                         return PTR_ERR(newxprt);
276                 }
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 int svc_create_xprt(struct svc_serv *serv, const char *xprt_name,
289                     struct net *net, const int family,
290                     const unsigned short port, int flags)
291 {
292         int err;
293 
294         dprintk("svc: creating transport %s[%d]\n", xprt_name, port);
295         err = _svc_create_xprt(serv, xprt_name, net, family, port, flags);
296         if (err == -EPROTONOSUPPORT) {
297                 request_module("svc%s", xprt_name);
298                 err = _svc_create_xprt(serv, xprt_name, net, family, port, flags);
299         }
300         if (err)
301                 dprintk("svc: transport %s not found, err %d\n",
302                         xprt_name, err);
303         return err;
304 }
305 EXPORT_SYMBOL_GPL(svc_create_xprt);
306 
307 /*
308  * Copy the local and remote xprt addresses to the rqstp structure
309  */
310 void svc_xprt_copy_addrs(struct svc_rqst *rqstp, struct svc_xprt *xprt)
311 {
312         memcpy(&rqstp->rq_addr, &xprt->xpt_remote, xprt->xpt_remotelen);
313         rqstp->rq_addrlen = xprt->xpt_remotelen;
314 
315         /*
316          * Destination address in request is needed for binding the
317          * source address in RPC replies/callbacks later.
318          */
319         memcpy(&rqstp->rq_daddr, &xprt->xpt_local, xprt->xpt_locallen);
320         rqstp->rq_daddrlen = xprt->xpt_locallen;
321 }
322 EXPORT_SYMBOL_GPL(svc_xprt_copy_addrs);
323 
324 /**
325  * svc_print_addr - Format rq_addr field for printing
326  * @rqstp: svc_rqst struct containing address to print
327  * @buf: target buffer for formatted address
328  * @len: length of target buffer
329  *
330  */
331 char *svc_print_addr(struct svc_rqst *rqstp, char *buf, size_t len)
332 {
333         return __svc_print_addr(svc_addr(rqstp), buf, len);
334 }
335 EXPORT_SYMBOL_GPL(svc_print_addr);
336 
337 static bool svc_xprt_slots_in_range(struct svc_xprt *xprt)
338 {
339         unsigned int limit = svc_rpc_per_connection_limit;
340         int nrqsts = atomic_read(&xprt->xpt_nr_rqsts);
341 
342         return limit == 0 || (nrqsts >= 0 && nrqsts < limit);
343 }
344 
345 static bool svc_xprt_reserve_slot(struct svc_rqst *rqstp, struct svc_xprt *xprt)
346 {
347         if (!test_bit(RQ_DATA, &rqstp->rq_flags)) {
348                 if (!svc_xprt_slots_in_range(xprt))
349                         return false;
350                 atomic_inc(&xprt->xpt_nr_rqsts);
351                 set_bit(RQ_DATA, &rqstp->rq_flags);
352         }
353         return true;
354 }
355 
356 static void svc_xprt_release_slot(struct svc_rqst *rqstp)
357 {
358         struct svc_xprt *xprt = rqstp->rq_xprt;
359         if (test_and_clear_bit(RQ_DATA, &rqstp->rq_flags)) {
360                 atomic_dec(&xprt->xpt_nr_rqsts);
361                 svc_xprt_enqueue(xprt);
362         }
363 }
364 
365 static bool svc_xprt_has_something_to_do(struct svc_xprt *xprt)
366 {
367         if (xprt->xpt_flags & ((1<<XPT_CONN)|(1<<XPT_CLOSE)))
368                 return true;
369         if (xprt->xpt_flags & ((1<<XPT_DATA)|(1<<XPT_DEFERRED))) {
370                 if (xprt->xpt_ops->xpo_has_wspace(xprt) &&
371                     svc_xprt_slots_in_range(xprt))
372                         return true;
373                 trace_svc_xprt_no_write_space(xprt);
374                 return false;
375         }
376         return false;
377 }
378 
379 void svc_xprt_do_enqueue(struct svc_xprt *xprt)
380 {
381         struct svc_pool *pool;
382         struct svc_rqst *rqstp = NULL;
383         int cpu;
384 
385         if (!svc_xprt_has_something_to_do(xprt))
386                 return;
387 
388         /* Mark transport as busy. It will remain in this state until
389          * the provider calls svc_xprt_received. We update XPT_BUSY
390          * atomically because it also guards against trying to enqueue
391          * the transport twice.
392          */
393         if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
394                 return;
395 
396         cpu = get_cpu();
397         pool = svc_pool_for_cpu(xprt->xpt_server, cpu);
398 
399         atomic_long_inc(&pool->sp_stats.packets);
400 
401         spin_lock_bh(&pool->sp_lock);
402         list_add_tail(&xprt->xpt_ready, &pool->sp_sockets);
403         pool->sp_stats.sockets_queued++;
404         spin_unlock_bh(&pool->sp_lock);
405 
406         /* find a thread for this xprt */
407         rcu_read_lock();
408         list_for_each_entry_rcu(rqstp, &pool->sp_all_threads, rq_all) {
409                 if (test_and_set_bit(RQ_BUSY, &rqstp->rq_flags))
410                         continue;
411                 atomic_long_inc(&pool->sp_stats.threads_woken);
412                 rqstp->rq_qtime = ktime_get();
413                 wake_up_process(rqstp->rq_task);
414                 goto out_unlock;
415         }
416         set_bit(SP_CONGESTED, &pool->sp_flags);
417         rqstp = NULL;
418 out_unlock:
419         rcu_read_unlock();
420         put_cpu();
421         trace_svc_xprt_do_enqueue(xprt, rqstp);
422 }
423 EXPORT_SYMBOL_GPL(svc_xprt_do_enqueue);
424 
425 /*
426  * Queue up a transport with data pending. If there are idle nfsd
427  * processes, wake 'em up.
428  *
429  */
430 void svc_xprt_enqueue(struct svc_xprt *xprt)
431 {
432         if (test_bit(XPT_BUSY, &xprt->xpt_flags))
433                 return;
434         xprt->xpt_server->sv_ops->svo_enqueue_xprt(xprt);
435 }
436 EXPORT_SYMBOL_GPL(svc_xprt_enqueue);
437 
438 /*
439  * Dequeue the first transport, if there is one.
440  */
441 static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool)
442 {
443         struct svc_xprt *xprt = NULL;
444 
445         if (list_empty(&pool->sp_sockets))
446                 goto out;
447 
448         spin_lock_bh(&pool->sp_lock);
449         if (likely(!list_empty(&pool->sp_sockets))) {
450                 xprt = list_first_entry(&pool->sp_sockets,
451                                         struct svc_xprt, xpt_ready);
452                 list_del_init(&xprt->xpt_ready);
453                 svc_xprt_get(xprt);
454         }
455         spin_unlock_bh(&pool->sp_lock);
456 out:
457         return xprt;
458 }
459 
460 /**
461  * svc_reserve - change the space reserved for the reply to a request.
462  * @rqstp:  The request in question
463  * @space: new max space to reserve
464  *
465  * Each request reserves some space on the output queue of the transport
466  * to make sure the reply fits.  This function reduces that reserved
467  * space to be the amount of space used already, plus @space.
468  *
469  */
470 void svc_reserve(struct svc_rqst *rqstp, int space)
471 {
472         space += rqstp->rq_res.head[0].iov_len;
473 
474         if (space < rqstp->rq_reserved) {
475                 struct svc_xprt *xprt = rqstp->rq_xprt;
476                 atomic_sub((rqstp->rq_reserved - space), &xprt->xpt_reserved);
477                 rqstp->rq_reserved = space;
478 
479                 svc_xprt_enqueue(xprt);
480         }
481 }
482 EXPORT_SYMBOL_GPL(svc_reserve);
483 
484 static void svc_xprt_release(struct svc_rqst *rqstp)
485 {
486         struct svc_xprt *xprt = rqstp->rq_xprt;
487 
488         xprt->xpt_ops->xpo_release_rqst(rqstp);
489 
490         kfree(rqstp->rq_deferred);
491         rqstp->rq_deferred = NULL;
492 
493         svc_free_res_pages(rqstp);
494         rqstp->rq_res.page_len = 0;
495         rqstp->rq_res.page_base = 0;
496 
497         /* Reset response buffer and release
498          * the reservation.
499          * But first, check that enough space was reserved
500          * for the reply, otherwise we have a bug!
501          */
502         if ((rqstp->rq_res.len) >  rqstp->rq_reserved)
503                 printk(KERN_ERR "RPC request reserved %d but used %d\n",
504                        rqstp->rq_reserved,
505                        rqstp->rq_res.len);
506 
507         rqstp->rq_res.head[0].iov_len = 0;
508         svc_reserve(rqstp, 0);
509         svc_xprt_release_slot(rqstp);
510         rqstp->rq_xprt = NULL;
511         svc_xprt_put(xprt);
512 }
513 
514 /*
515  * Some svc_serv's will have occasional work to do, even when a xprt is not
516  * waiting to be serviced. This function is there to "kick" a task in one of
517  * those services so that it can wake up and do that work. Note that we only
518  * bother with pool 0 as we don't need to wake up more than one thread for
519  * this purpose.
520  */
521 void svc_wake_up(struct svc_serv *serv)
522 {
523         struct svc_rqst *rqstp;
524         struct svc_pool *pool;
525 
526         pool = &serv->sv_pools[0];
527 
528         rcu_read_lock();
529         list_for_each_entry_rcu(rqstp, &pool->sp_all_threads, rq_all) {
530                 /* skip any that aren't queued */
531                 if (test_bit(RQ_BUSY, &rqstp->rq_flags))
532                         continue;
533                 rcu_read_unlock();
534                 wake_up_process(rqstp->rq_task);
535                 trace_svc_wake_up(rqstp->rq_task->pid);
536                 return;
537         }
538         rcu_read_unlock();
539 
540         /* No free entries available */
541         set_bit(SP_TASK_PENDING, &pool->sp_flags);
542         smp_wmb();
543         trace_svc_wake_up(0);
544 }
545 EXPORT_SYMBOL_GPL(svc_wake_up);
546 
547 int svc_port_is_privileged(struct sockaddr *sin)
548 {
549         switch (sin->sa_family) {
550         case AF_INET:
551                 return ntohs(((struct sockaddr_in *)sin)->sin_port)
552                         < PROT_SOCK;
553         case AF_INET6:
554                 return ntohs(((struct sockaddr_in6 *)sin)->sin6_port)
555                         < PROT_SOCK;
556         default:
557                 return 0;
558         }
559 }
560 
561 /*
562  * Make sure that we don't have too many active connections. If we have,
563  * something must be dropped. It's not clear what will happen if we allow
564  * "too many" connections, but when dealing with network-facing software,
565  * we have to code defensively. Here we do that by imposing hard limits.
566  *
567  * There's no point in trying to do random drop here for DoS
568  * prevention. The NFS clients does 1 reconnect in 15 seconds. An
569  * attacker can easily beat that.
570  *
571  * The only somewhat efficient mechanism would be if drop old
572  * connections from the same IP first. But right now we don't even
573  * record the client IP in svc_sock.
574  *
575  * single-threaded services that expect a lot of clients will probably
576  * need to set sv_maxconn to override the default value which is based
577  * on the number of threads
578  */
579 static void svc_check_conn_limits(struct svc_serv *serv)
580 {
581         unsigned int limit = serv->sv_maxconn ? serv->sv_maxconn :
582                                 (serv->sv_nrthreads+3) * 20;
583 
584         if (serv->sv_tmpcnt > limit) {
585                 struct svc_xprt *xprt = NULL;
586                 spin_lock_bh(&serv->sv_lock);
587                 if (!list_empty(&serv->sv_tempsocks)) {
588                         /* Try to help the admin */
589                         net_notice_ratelimited("%s: too many open connections, consider increasing the %s\n",
590                                                serv->sv_name, serv->sv_maxconn ?
591                                                "max number of connections" :
592                                                "number of threads");
593                         /*
594                          * Always select the oldest connection. It's not fair,
595                          * but so is life
596                          */
597                         xprt = list_entry(serv->sv_tempsocks.prev,
598                                           struct svc_xprt,
599                                           xpt_list);
600                         set_bit(XPT_CLOSE, &xprt->xpt_flags);
601                         svc_xprt_get(xprt);
602                 }
603                 spin_unlock_bh(&serv->sv_lock);
604 
605                 if (xprt) {
606                         svc_xprt_enqueue(xprt);
607                         svc_xprt_put(xprt);
608                 }
609         }
610 }
611 
612 static int svc_alloc_arg(struct svc_rqst *rqstp)
613 {
614         struct svc_serv *serv = rqstp->rq_server;
615         struct xdr_buf *arg;
616         int pages;
617         int i;
618 
619         /* now allocate needed pages.  If we get a failure, sleep briefly */
620         pages = (serv->sv_max_mesg + 2 * PAGE_SIZE) >> PAGE_SHIFT;
621         if (pages > RPCSVC_MAXPAGES) {
622                 pr_warn_once("svc: warning: pages=%u > RPCSVC_MAXPAGES=%lu\n",
623                              pages, RPCSVC_MAXPAGES);
624                 /* use as many pages as possible */
625                 pages = RPCSVC_MAXPAGES;
626         }
627         for (i = 0; i < pages ; i++)
628                 while (rqstp->rq_pages[i] == NULL) {
629                         struct page *p = alloc_page(GFP_KERNEL);
630                         if (!p) {
631                                 set_current_state(TASK_INTERRUPTIBLE);
632                                 if (signalled() || kthread_should_stop()) {
633                                         set_current_state(TASK_RUNNING);
634                                         return -EINTR;
635                                 }
636                                 schedule_timeout(msecs_to_jiffies(500));
637                         }
638                         rqstp->rq_pages[i] = p;
639                 }
640         rqstp->rq_page_end = &rqstp->rq_pages[i];
641         rqstp->rq_pages[i++] = NULL; /* this might be seen in nfs_read_actor */
642 
643         /* Make arg->head point to first page and arg->pages point to rest */
644         arg = &rqstp->rq_arg;
645         arg->head[0].iov_base = page_address(rqstp->rq_pages[0]);
646         arg->head[0].iov_len = PAGE_SIZE;
647         arg->pages = rqstp->rq_pages + 1;
648         arg->page_base = 0;
649         /* save at least one page for response */
650         arg->page_len = (pages-2)*PAGE_SIZE;
651         arg->len = (pages-1)*PAGE_SIZE;
652         arg->tail[0].iov_len = 0;
653         return 0;
654 }
655 
656 static bool
657 rqst_should_sleep(struct svc_rqst *rqstp)
658 {
659         struct svc_pool         *pool = rqstp->rq_pool;
660 
661         /* did someone call svc_wake_up? */
662         if (test_and_clear_bit(SP_TASK_PENDING, &pool->sp_flags))
663                 return false;
664 
665         /* was a socket queued? */
666         if (!list_empty(&pool->sp_sockets))
667                 return false;
668 
669         /* are we shutting down? */
670         if (signalled() || kthread_should_stop())
671                 return false;
672 
673         /* are we freezing? */
674         if (freezing(current))
675                 return false;
676 
677         return true;
678 }
679 
680 static struct svc_xprt *svc_get_next_xprt(struct svc_rqst *rqstp, long timeout)
681 {
682         struct svc_pool         *pool = rqstp->rq_pool;
683         long                    time_left = 0;
684 
685         /* rq_xprt should be clear on entry */
686         WARN_ON_ONCE(rqstp->rq_xprt);
687 
688         rqstp->rq_xprt = svc_xprt_dequeue(pool);
689         if (rqstp->rq_xprt)
690                 goto out_found;
691 
692         /*
693          * We have to be able to interrupt this wait
694          * to bring down the daemons ...
695          */
696         set_current_state(TASK_INTERRUPTIBLE);
697         smp_mb__before_atomic();
698         clear_bit(SP_CONGESTED, &pool->sp_flags);
699         clear_bit(RQ_BUSY, &rqstp->rq_flags);
700         smp_mb__after_atomic();
701 
702         if (likely(rqst_should_sleep(rqstp)))
703                 time_left = schedule_timeout(timeout);
704         else
705                 __set_current_state(TASK_RUNNING);
706 
707         try_to_freeze();
708 
709         set_bit(RQ_BUSY, &rqstp->rq_flags);
710         smp_mb__after_atomic();
711         rqstp->rq_xprt = svc_xprt_dequeue(pool);
712         if (rqstp->rq_xprt)
713                 goto out_found;
714 
715         if (!time_left)
716                 atomic_long_inc(&pool->sp_stats.threads_timedout);
717 
718         if (signalled() || kthread_should_stop())
719                 return ERR_PTR(-EINTR);
720         return ERR_PTR(-EAGAIN);
721 out_found:
722         /* Normally we will wait up to 5 seconds for any required
723          * cache information to be provided.
724          */
725         if (!test_bit(SP_CONGESTED, &pool->sp_flags))
726                 rqstp->rq_chandle.thread_wait = 5*HZ;
727         else
728                 rqstp->rq_chandle.thread_wait = 1*HZ;
729         trace_svc_xprt_dequeue(rqstp);
730         return rqstp->rq_xprt;
731 }
732 
733 static void svc_add_new_temp_xprt(struct svc_serv *serv, struct svc_xprt *newxpt)
734 {
735         spin_lock_bh(&serv->sv_lock);
736         set_bit(XPT_TEMP, &newxpt->xpt_flags);
737         list_add(&newxpt->xpt_list, &serv->sv_tempsocks);
738         serv->sv_tmpcnt++;
739         if (serv->sv_temptimer.function == NULL) {
740                 /* setup timer to age temp transports */
741                 serv->sv_temptimer.function = svc_age_temp_xprts;
742                 mod_timer(&serv->sv_temptimer,
743                           jiffies + svc_conn_age_period * HZ);
744         }
745         spin_unlock_bh(&serv->sv_lock);
746         svc_xprt_received(newxpt);
747 }
748 
749 static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
750 {
751         struct svc_serv *serv = rqstp->rq_server;
752         int len = 0;
753 
754         if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) {
755                 dprintk("svc_recv: found XPT_CLOSE\n");
756                 if (test_and_clear_bit(XPT_KILL_TEMP, &xprt->xpt_flags))
757                         xprt->xpt_ops->xpo_kill_temp_xprt(xprt);
758                 svc_delete_xprt(xprt);
759                 /* Leave XPT_BUSY set on the dead xprt: */
760                 goto out;
761         }
762         if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) {
763                 struct svc_xprt *newxpt;
764                 /*
765                  * We know this module_get will succeed because the
766                  * listener holds a reference too
767                  */
768                 __module_get(xprt->xpt_class->xcl_owner);
769                 svc_check_conn_limits(xprt->xpt_server);
770                 newxpt = xprt->xpt_ops->xpo_accept(xprt);
771                 if (newxpt)
772                         svc_add_new_temp_xprt(serv, newxpt);
773                 else
774                         module_put(xprt->xpt_class->xcl_owner);
775         } else if (svc_xprt_reserve_slot(rqstp, xprt)) {
776                 /* XPT_DATA|XPT_DEFERRED case: */
777                 dprintk("svc: server %p, pool %u, transport %p, inuse=%d\n",
778                         rqstp, rqstp->rq_pool->sp_id, xprt,
779                         kref_read(&xprt->xpt_ref));
780                 rqstp->rq_deferred = svc_deferred_dequeue(xprt);
781                 if (rqstp->rq_deferred)
782                         len = svc_deferred_recv(rqstp);
783                 else
784                         len = xprt->xpt_ops->xpo_recvfrom(rqstp);
785                 rqstp->rq_stime = ktime_get();
786                 rqstp->rq_reserved = serv->sv_max_mesg;
787                 atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
788         }
789         /* clear XPT_BUSY: */
790         svc_xprt_received(xprt);
791 out:
792         trace_svc_handle_xprt(xprt, len);
793         return len;
794 }
795 
796 /*
797  * Receive the next request on any transport.  This code is carefully
798  * organised not to touch any cachelines in the shared svc_serv
799  * structure, only cachelines in the local svc_pool.
800  */
801 int svc_recv(struct svc_rqst *rqstp, long timeout)
802 {
803         struct svc_xprt         *xprt = NULL;
804         struct svc_serv         *serv = rqstp->rq_server;
805         int                     len, err;
806 
807         dprintk("svc: server %p waiting for data (to = %ld)\n",
808                 rqstp, timeout);
809 
810         if (rqstp->rq_xprt)
811                 printk(KERN_ERR
812                         "svc_recv: service %p, transport not NULL!\n",
813                          rqstp);
814 
815         err = svc_alloc_arg(rqstp);
816         if (err)
817                 goto out;
818 
819         try_to_freeze();
820         cond_resched();
821         err = -EINTR;
822         if (signalled() || kthread_should_stop())
823                 goto out;
824 
825         xprt = svc_get_next_xprt(rqstp, timeout);
826         if (IS_ERR(xprt)) {
827                 err = PTR_ERR(xprt);
828                 goto out;
829         }
830 
831         len = svc_handle_xprt(rqstp, xprt);
832 
833         /* No data, incomplete (TCP) read, or accept() */
834         err = -EAGAIN;
835         if (len <= 0)
836                 goto out_release;
837 
838         clear_bit(XPT_OLD, &xprt->xpt_flags);
839 
840         xprt->xpt_ops->xpo_secure_port(rqstp);
841         rqstp->rq_chandle.defer = svc_defer;
842         rqstp->rq_xid = svc_getu32(&rqstp->rq_arg.head[0]);
843 
844         if (serv->sv_stats)
845                 serv->sv_stats->netcnt++;
846         trace_svc_recv(rqstp, len);
847         return len;
848 out_release:
849         rqstp->rq_res.len = 0;
850         svc_xprt_release(rqstp);
851 out:
852         return err;
853 }
854 EXPORT_SYMBOL_GPL(svc_recv);
855 
856 /*
857  * Drop request
858  */
859 void svc_drop(struct svc_rqst *rqstp)
860 {
861         trace_svc_drop(rqstp);
862         dprintk("svc: xprt %p dropped request\n", rqstp->rq_xprt);
863         svc_xprt_release(rqstp);
864 }
865 EXPORT_SYMBOL_GPL(svc_drop);
866 
867 /*
868  * Return reply to client.
869  */
870 int svc_send(struct svc_rqst *rqstp)
871 {
872         struct svc_xprt *xprt;
873         int             len = -EFAULT;
874         struct xdr_buf  *xb;
875 
876         xprt = rqstp->rq_xprt;
877         if (!xprt)
878                 goto out;
879 
880         /* release the receive skb before sending the reply */
881         xprt->xpt_ops->xpo_release_rqst(rqstp);
882 
883         /* calculate over-all length */
884         xb = &rqstp->rq_res;
885         xb->len = xb->head[0].iov_len +
886                 xb->page_len +
887                 xb->tail[0].iov_len;
888 
889         /* Grab mutex to serialize outgoing data. */
890         mutex_lock(&xprt->xpt_mutex);
891         trace_svc_stats_latency(rqstp);
892         if (test_bit(XPT_DEAD, &xprt->xpt_flags)
893                         || test_bit(XPT_CLOSE, &xprt->xpt_flags))
894                 len = -ENOTCONN;
895         else
896                 len = xprt->xpt_ops->xpo_sendto(rqstp);
897         mutex_unlock(&xprt->xpt_mutex);
898         rpc_wake_up(&xprt->xpt_bc_pending);
899         trace_svc_send(rqstp, len);
900         svc_xprt_release(rqstp);
901 
902         if (len == -ECONNREFUSED || len == -ENOTCONN || len == -EAGAIN)
903                 len = 0;
904 out:
905         return len;
906 }
907 
908 /*
909  * Timer function to close old temporary transports, using
910  * a mark-and-sweep algorithm.
911  */
912 static void svc_age_temp_xprts(struct timer_list *t)
913 {
914         struct svc_serv *serv = from_timer(serv, t, sv_temptimer);
915         struct svc_xprt *xprt;
916         struct list_head *le, *next;
917 
918         dprintk("svc_age_temp_xprts\n");
919 
920         if (!spin_trylock_bh(&serv->sv_lock)) {
921                 /* busy, try again 1 sec later */
922                 dprintk("svc_age_temp_xprts: busy\n");
923                 mod_timer(&serv->sv_temptimer, jiffies + HZ);
924                 return;
925         }
926 
927         list_for_each_safe(le, next, &serv->sv_tempsocks) {
928                 xprt = list_entry(le, struct svc_xprt, xpt_list);
929 
930                 /* First time through, just mark it OLD. Second time
931                  * through, close it. */
932                 if (!test_and_set_bit(XPT_OLD, &xprt->xpt_flags))
933                         continue;
934                 if (kref_read(&xprt->xpt_ref) > 1 ||
935                     test_bit(XPT_BUSY, &xprt->xpt_flags))
936                         continue;
937                 list_del_init(le);
938                 set_bit(XPT_CLOSE, &xprt->xpt_flags);
939                 dprintk("queuing xprt %p for closing\n", xprt);
940 
941                 /* a thread will dequeue and close it soon */
942                 svc_xprt_enqueue(xprt);
943         }
944         spin_unlock_bh(&serv->sv_lock);
945 
946         mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ);
947 }
948 
949 /* Close temporary transports whose xpt_local matches server_addr immediately
950  * instead of waiting for them to be picked up by the timer.
951  *
952  * This is meant to be called from a notifier_block that runs when an ip
953  * address is deleted.
954  */
955 void svc_age_temp_xprts_now(struct svc_serv *serv, struct sockaddr *server_addr)
956 {
957         struct svc_xprt *xprt;
958         struct list_head *le, *next;
959         LIST_HEAD(to_be_closed);
960 
961         spin_lock_bh(&serv->sv_lock);
962         list_for_each_safe(le, next, &serv->sv_tempsocks) {
963                 xprt = list_entry(le, struct svc_xprt, xpt_list);
964                 if (rpc_cmp_addr(server_addr, (struct sockaddr *)
965                                 &xprt->xpt_local)) {
966                         dprintk("svc_age_temp_xprts_now: found %p\n", xprt);
967                         list_move(le, &to_be_closed);
968                 }
969         }
970         spin_unlock_bh(&serv->sv_lock);
971 
972         while (!list_empty(&to_be_closed)) {
973                 le = to_be_closed.next;
974                 list_del_init(le);
975                 xprt = list_entry(le, struct svc_xprt, xpt_list);
976                 set_bit(XPT_CLOSE, &xprt->xpt_flags);
977                 set_bit(XPT_KILL_TEMP, &xprt->xpt_flags);
978                 dprintk("svc_age_temp_xprts_now: queuing xprt %p for closing\n",
979                                 xprt);
980                 svc_xprt_enqueue(xprt);
981         }
982 }
983 EXPORT_SYMBOL_GPL(svc_age_temp_xprts_now);
984 
985 static void call_xpt_users(struct svc_xprt *xprt)
986 {
987         struct svc_xpt_user *u;
988 
989         spin_lock(&xprt->xpt_lock);
990         while (!list_empty(&xprt->xpt_users)) {
991                 u = list_first_entry(&xprt->xpt_users, struct svc_xpt_user, list);
992                 list_del_init(&u->list);
993                 u->callback(u);
994         }
995         spin_unlock(&xprt->xpt_lock);
996 }
997 
998 /*
999  * Remove a dead transport
1000  */
1001 static void svc_delete_xprt(struct svc_xprt *xprt)
1002 {
1003         struct svc_serv *serv = xprt->xpt_server;
1004         struct svc_deferred_req *dr;
1005 
1006         /* Only do this once */
1007         if (test_and_set_bit(XPT_DEAD, &xprt->xpt_flags))
1008                 BUG();
1009 
1010         dprintk("svc: svc_delete_xprt(%p)\n", xprt);
1011         xprt->xpt_ops->xpo_detach(xprt);
1012 
1013         spin_lock_bh(&serv->sv_lock);
1014         list_del_init(&xprt->xpt_list);
1015         WARN_ON_ONCE(!list_empty(&xprt->xpt_ready));
1016         if (test_bit(XPT_TEMP, &xprt->xpt_flags))
1017                 serv->sv_tmpcnt--;
1018         spin_unlock_bh(&serv->sv_lock);
1019 
1020         while ((dr = svc_deferred_dequeue(xprt)) != NULL)
1021                 kfree(dr);
1022 
1023         call_xpt_users(xprt);
1024         svc_xprt_put(xprt);
1025 }
1026 
1027 void svc_close_xprt(struct svc_xprt *xprt)
1028 {
1029         set_bit(XPT_CLOSE, &xprt->xpt_flags);
1030         if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
1031                 /* someone else will have to effect the close */
1032                 return;
1033         /*
1034          * We expect svc_close_xprt() to work even when no threads are
1035          * running (e.g., while configuring the server before starting
1036          * any threads), so if the transport isn't busy, we delete
1037          * it ourself:
1038          */
1039         svc_delete_xprt(xprt);
1040 }
1041 EXPORT_SYMBOL_GPL(svc_close_xprt);
1042 
1043 static int svc_close_list(struct svc_serv *serv, struct list_head *xprt_list, struct net *net)
1044 {
1045         struct svc_xprt *xprt;
1046         int ret = 0;
1047 
1048         spin_lock(&serv->sv_lock);
1049         list_for_each_entry(xprt, xprt_list, xpt_list) {
1050                 if (xprt->xpt_net != net)
1051                         continue;
1052                 ret++;
1053                 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1054                 svc_xprt_enqueue(xprt);
1055         }
1056         spin_unlock(&serv->sv_lock);
1057         return ret;
1058 }
1059 
1060 static struct svc_xprt *svc_dequeue_net(struct svc_serv *serv, struct net *net)
1061 {
1062         struct svc_pool *pool;
1063         struct svc_xprt *xprt;
1064         struct svc_xprt *tmp;
1065         int i;
1066 
1067         for (i = 0; i < serv->sv_nrpools; i++) {
1068                 pool = &serv->sv_pools[i];
1069 
1070                 spin_lock_bh(&pool->sp_lock);
1071                 list_for_each_entry_safe(xprt, tmp, &pool->sp_sockets, xpt_ready) {
1072                         if (xprt->xpt_net != net)
1073                                 continue;
1074                         list_del_init(&xprt->xpt_ready);
1075                         spin_unlock_bh(&pool->sp_lock);
1076                         return xprt;
1077                 }
1078                 spin_unlock_bh(&pool->sp_lock);
1079         }
1080         return NULL;
1081 }
1082 
1083 static void svc_clean_up_xprts(struct svc_serv *serv, struct net *net)
1084 {
1085         struct svc_xprt *xprt;
1086 
1087         while ((xprt = svc_dequeue_net(serv, net))) {
1088                 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1089                 svc_delete_xprt(xprt);
1090         }
1091 }
1092 
1093 /*
1094  * Server threads may still be running (especially in the case where the
1095  * service is still running in other network namespaces).
1096  *
1097  * So we shut down sockets the same way we would on a running server, by
1098  * setting XPT_CLOSE, enqueuing, and letting a thread pick it up to do
1099  * the close.  In the case there are no such other threads,
1100  * threads running, svc_clean_up_xprts() does a simple version of a
1101  * server's main event loop, and in the case where there are other
1102  * threads, we may need to wait a little while and then check again to
1103  * see if they're done.
1104  */
1105 void svc_close_net(struct svc_serv *serv, struct net *net)
1106 {
1107         int delay = 0;
1108 
1109         while (svc_close_list(serv, &serv->sv_permsocks, net) +
1110                svc_close_list(serv, &serv->sv_tempsocks, net)) {
1111 
1112                 svc_clean_up_xprts(serv, net);
1113                 msleep(delay++);
1114         }
1115 }
1116 
1117 /*
1118  * Handle defer and revisit of requests
1119  */
1120 
1121 static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
1122 {
1123         struct svc_deferred_req *dr =
1124                 container_of(dreq, struct svc_deferred_req, handle);
1125         struct svc_xprt *xprt = dr->xprt;
1126 
1127         spin_lock(&xprt->xpt_lock);
1128         set_bit(XPT_DEFERRED, &xprt->xpt_flags);
1129         if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) {
1130                 spin_unlock(&xprt->xpt_lock);
1131                 dprintk("revisit canceled\n");
1132                 svc_xprt_put(xprt);
1133                 trace_svc_drop_deferred(dr);
1134                 kfree(dr);
1135                 return;
1136         }
1137         dprintk("revisit queued\n");
1138         dr->xprt = NULL;
1139         list_add(&dr->handle.recent, &xprt->xpt_deferred);
1140         spin_unlock(&xprt->xpt_lock);
1141         svc_xprt_enqueue(xprt);
1142         svc_xprt_put(xprt);
1143 }
1144 
1145 /*
1146  * Save the request off for later processing. The request buffer looks
1147  * like this:
1148  *
1149  * <xprt-header><rpc-header><rpc-pagelist><rpc-tail>
1150  *
1151  * This code can only handle requests that consist of an xprt-header
1152  * and rpc-header.
1153  */
1154 static struct cache_deferred_req *svc_defer(struct cache_req *req)
1155 {
1156         struct svc_rqst *rqstp = container_of(req, struct svc_rqst, rq_chandle);
1157         struct svc_deferred_req *dr;
1158 
1159         if (rqstp->rq_arg.page_len || !test_bit(RQ_USEDEFERRAL, &rqstp->rq_flags))
1160                 return NULL; /* if more than a page, give up FIXME */
1161         if (rqstp->rq_deferred) {
1162                 dr = rqstp->rq_deferred;
1163                 rqstp->rq_deferred = NULL;
1164         } else {
1165                 size_t skip;
1166                 size_t size;
1167                 /* FIXME maybe discard if size too large */
1168                 size = sizeof(struct svc_deferred_req) + rqstp->rq_arg.len;
1169                 dr = kmalloc(size, GFP_KERNEL);
1170                 if (dr == NULL)
1171                         return NULL;
1172 
1173                 dr->handle.owner = rqstp->rq_server;
1174                 dr->prot = rqstp->rq_prot;
1175                 memcpy(&dr->addr, &rqstp->rq_addr, rqstp->rq_addrlen);
1176                 dr->addrlen = rqstp->rq_addrlen;
1177                 dr->daddr = rqstp->rq_daddr;
1178                 dr->argslen = rqstp->rq_arg.len >> 2;
1179                 dr->xprt_hlen = rqstp->rq_xprt_hlen;
1180 
1181                 /* back up head to the start of the buffer and copy */
1182                 skip = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len;
1183                 memcpy(dr->args, rqstp->rq_arg.head[0].iov_base - skip,
1184                        dr->argslen << 2);
1185         }
1186         svc_xprt_get(rqstp->rq_xprt);
1187         dr->xprt = rqstp->rq_xprt;
1188         set_bit(RQ_DROPME, &rqstp->rq_flags);
1189 
1190         dr->handle.revisit = svc_revisit;
1191         trace_svc_defer(rqstp);
1192         return &dr->handle;
1193 }
1194 
1195 /*
1196  * recv data from a deferred request into an active one
1197  */
1198 static int svc_deferred_recv(struct svc_rqst *rqstp)
1199 {
1200         struct svc_deferred_req *dr = rqstp->rq_deferred;
1201 
1202         /* setup iov_base past transport header */
1203         rqstp->rq_arg.head[0].iov_base = dr->args + (dr->xprt_hlen>>2);
1204         /* The iov_len does not include the transport header bytes */
1205         rqstp->rq_arg.head[0].iov_len = (dr->argslen<<2) - dr->xprt_hlen;
1206         rqstp->rq_arg.page_len = 0;
1207         /* The rq_arg.len includes the transport header bytes */
1208         rqstp->rq_arg.len     = dr->argslen<<2;
1209         rqstp->rq_prot        = dr->prot;
1210         memcpy(&rqstp->rq_addr, &dr->addr, dr->addrlen);
1211         rqstp->rq_addrlen     = dr->addrlen;
1212         /* Save off transport header len in case we get deferred again */
1213         rqstp->rq_xprt_hlen   = dr->xprt_hlen;
1214         rqstp->rq_daddr       = dr->daddr;
1215         rqstp->rq_respages    = rqstp->rq_pages;
1216         return (dr->argslen<<2) - dr->xprt_hlen;
1217 }
1218 
1219 
1220 static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt)
1221 {
1222         struct svc_deferred_req *dr = NULL;
1223 
1224         if (!test_bit(XPT_DEFERRED, &xprt->xpt_flags))
1225                 return NULL;
1226         spin_lock(&xprt->xpt_lock);
1227         if (!list_empty(&xprt->xpt_deferred)) {
1228                 dr = list_entry(xprt->xpt_deferred.next,
1229                                 struct svc_deferred_req,
1230                                 handle.recent);
1231                 list_del_init(&dr->handle.recent);
1232                 trace_svc_revisit_deferred(dr);
1233         } else
1234                 clear_bit(XPT_DEFERRED, &xprt->xpt_flags);
1235         spin_unlock(&xprt->xpt_lock);
1236         return dr;
1237 }
1238 
1239 /**
1240  * svc_find_xprt - find an RPC transport instance
1241  * @serv: pointer to svc_serv to search
1242  * @xcl_name: C string containing transport's class name
1243  * @net: owner net pointer
1244  * @af: Address family of transport's local address
1245  * @port: transport's IP port number
1246  *
1247  * Return the transport instance pointer for the endpoint accepting
1248  * connections/peer traffic from the specified transport class,
1249  * address family and port.
1250  *
1251  * Specifying 0 for the address family or port is effectively a
1252  * wild-card, and will result in matching the first transport in the
1253  * service's list that has a matching class name.
1254  */
1255 struct svc_xprt *svc_find_xprt(struct svc_serv *serv, const char *xcl_name,
1256                                struct net *net, const sa_family_t af,
1257                                const unsigned short port)
1258 {
1259         struct svc_xprt *xprt;
1260         struct svc_xprt *found = NULL;
1261 
1262         /* Sanity check the args */
1263         if (serv == NULL || xcl_name == NULL)
1264                 return found;
1265 
1266         spin_lock_bh(&serv->sv_lock);
1267         list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1268                 if (xprt->xpt_net != net)
1269                         continue;
1270                 if (strcmp(xprt->xpt_class->xcl_name, xcl_name))
1271                         continue;
1272                 if (af != AF_UNSPEC && af != xprt->xpt_local.ss_family)
1273                         continue;
1274                 if (port != 0 && port != svc_xprt_local_port(xprt))
1275                         continue;
1276                 found = xprt;
1277                 svc_xprt_get(xprt);
1278                 break;
1279         }
1280         spin_unlock_bh(&serv->sv_lock);
1281         return found;
1282 }
1283 EXPORT_SYMBOL_GPL(svc_find_xprt);
1284 
1285 static int svc_one_xprt_name(const struct svc_xprt *xprt,
1286                              char *pos, int remaining)
1287 {
1288         int len;
1289 
1290         len = snprintf(pos, remaining, "%s %u\n",
1291                         xprt->xpt_class->xcl_name,
1292                         svc_xprt_local_port(xprt));
1293         if (len >= remaining)
1294                 return -ENAMETOOLONG;
1295         return len;
1296 }
1297 
1298 /**
1299  * svc_xprt_names - format a buffer with a list of transport names
1300  * @serv: pointer to an RPC service
1301  * @buf: pointer to a buffer to be filled in
1302  * @buflen: length of buffer to be filled in
1303  *
1304  * Fills in @buf with a string containing a list of transport names,
1305  * each name terminated with '\n'.
1306  *
1307  * Returns positive length of the filled-in string on success; otherwise
1308  * a negative errno value is returned if an error occurs.
1309  */
1310 int svc_xprt_names(struct svc_serv *serv, char *buf, const int buflen)
1311 {
1312         struct svc_xprt *xprt;
1313         int len, totlen;
1314         char *pos;
1315 
1316         /* Sanity check args */
1317         if (!serv)
1318                 return 0;
1319 
1320         spin_lock_bh(&serv->sv_lock);
1321 
1322         pos = buf;
1323         totlen = 0;
1324         list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1325                 len = svc_one_xprt_name(xprt, pos, buflen - totlen);
1326                 if (len < 0) {
1327                         *buf = '\0';
1328                         totlen = len;
1329                 }
1330                 if (len <= 0)
1331                         break;
1332 
1333                 pos += len;
1334                 totlen += len;
1335         }
1336 
1337         spin_unlock_bh(&serv->sv_lock);
1338         return totlen;
1339 }
1340 EXPORT_SYMBOL_GPL(svc_xprt_names);
1341 
1342 
1343 /*----------------------------------------------------------------------------*/
1344 
1345 static void *svc_pool_stats_start(struct seq_file *m, loff_t *pos)
1346 {
1347         unsigned int pidx = (unsigned int)*pos;
1348         struct svc_serv *serv = m->private;
1349 
1350         dprintk("svc_pool_stats_start, *pidx=%u\n", pidx);
1351 
1352         if (!pidx)
1353                 return SEQ_START_TOKEN;
1354         return (pidx > serv->sv_nrpools ? NULL : &serv->sv_pools[pidx-1]);
1355 }
1356 
1357 static void *svc_pool_stats_next(struct seq_file *m, void *p, loff_t *pos)
1358 {
1359         struct svc_pool *pool = p;
1360         struct svc_serv *serv = m->private;
1361 
1362         dprintk("svc_pool_stats_next, *pos=%llu\n", *pos);
1363 
1364         if (p == SEQ_START_TOKEN) {
1365                 pool = &serv->sv_pools[0];
1366         } else {
1367                 unsigned int pidx = (pool - &serv->sv_pools[0]);
1368                 if (pidx < serv->sv_nrpools-1)
1369                         pool = &serv->sv_pools[pidx+1];
1370                 else
1371                         pool = NULL;
1372         }
1373         ++*pos;
1374         return pool;
1375 }
1376 
1377 static void svc_pool_stats_stop(struct seq_file *m, void *p)
1378 {
1379 }
1380 
1381 static int svc_pool_stats_show(struct seq_file *m, void *p)
1382 {
1383         struct svc_pool *pool = p;
1384 
1385         if (p == SEQ_START_TOKEN) {
1386                 seq_puts(m, "# pool packets-arrived sockets-enqueued threads-woken threads-timedout\n");
1387                 return 0;
1388         }
1389 
1390         seq_printf(m, "%u %lu %lu %lu %lu\n",
1391                 pool->sp_id,
1392                 (unsigned long)atomic_long_read(&pool->sp_stats.packets),
1393                 pool->sp_stats.sockets_queued,
1394                 (unsigned long)atomic_long_read(&pool->sp_stats.threads_woken),
1395                 (unsigned long)atomic_long_read(&pool->sp_stats.threads_timedout));
1396 
1397         return 0;
1398 }
1399 
1400 static const struct seq_operations svc_pool_stats_seq_ops = {
1401         .start  = svc_pool_stats_start,
1402         .next   = svc_pool_stats_next,
1403         .stop   = svc_pool_stats_stop,
1404         .show   = svc_pool_stats_show,
1405 };
1406 
1407 int svc_pool_stats_open(struct svc_serv *serv, struct file *file)
1408 {
1409         int err;
1410 
1411         err = seq_open(file, &svc_pool_stats_seq_ops);
1412         if (!err)
1413                 ((struct seq_file *) file->private_data)->private = serv;
1414         return err;
1415 }
1416 EXPORT_SYMBOL(svc_pool_stats_open);
1417 
1418 /*----------------------------------------------------------------------------*/
1419 

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