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

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