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Linux/net/sunrpc/svc.c

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  1 /*
  2  * linux/net/sunrpc/svc.c
  3  *
  4  * High-level RPC service routines
  5  *
  6  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
  7  *
  8  * Multiple threads pools and NUMAisation
  9  * Copyright (c) 2006 Silicon Graphics, Inc.
 10  * by Greg Banks <gnb@melbourne.sgi.com>
 11  */
 12 
 13 #include <linux/linkage.h>
 14 #include <linux/sched.h>
 15 #include <linux/errno.h>
 16 #include <linux/net.h>
 17 #include <linux/in.h>
 18 #include <linux/mm.h>
 19 #include <linux/interrupt.h>
 20 #include <linux/module.h>
 21 #include <linux/kthread.h>
 22 #include <linux/slab.h>
 23 
 24 #include <linux/sunrpc/types.h>
 25 #include <linux/sunrpc/xdr.h>
 26 #include <linux/sunrpc/stats.h>
 27 #include <linux/sunrpc/svcsock.h>
 28 #include <linux/sunrpc/clnt.h>
 29 #include <linux/sunrpc/bc_xprt.h>
 30 
 31 #include <trace/events/sunrpc.h>
 32 
 33 #define RPCDBG_FACILITY RPCDBG_SVCDSP
 34 
 35 static void svc_unregister(const struct svc_serv *serv, struct net *net);
 36 
 37 #define svc_serv_is_pooled(serv)    ((serv)->sv_ops->svo_function)
 38 
 39 #define SVC_POOL_DEFAULT        SVC_POOL_GLOBAL
 40 
 41 /*
 42  * Structure for mapping cpus to pools and vice versa.
 43  * Setup once during sunrpc initialisation.
 44  */
 45 struct svc_pool_map svc_pool_map = {
 46         .mode = SVC_POOL_DEFAULT
 47 };
 48 EXPORT_SYMBOL_GPL(svc_pool_map);
 49 
 50 static DEFINE_MUTEX(svc_pool_map_mutex);/* protects svc_pool_map.count only */
 51 
 52 static int
 53 param_set_pool_mode(const char *val, struct kernel_param *kp)
 54 {
 55         int *ip = (int *)kp->arg;
 56         struct svc_pool_map *m = &svc_pool_map;
 57         int err;
 58 
 59         mutex_lock(&svc_pool_map_mutex);
 60 
 61         err = -EBUSY;
 62         if (m->count)
 63                 goto out;
 64 
 65         err = 0;
 66         if (!strncmp(val, "auto", 4))
 67                 *ip = SVC_POOL_AUTO;
 68         else if (!strncmp(val, "global", 6))
 69                 *ip = SVC_POOL_GLOBAL;
 70         else if (!strncmp(val, "percpu", 6))
 71                 *ip = SVC_POOL_PERCPU;
 72         else if (!strncmp(val, "pernode", 7))
 73                 *ip = SVC_POOL_PERNODE;
 74         else
 75                 err = -EINVAL;
 76 
 77 out:
 78         mutex_unlock(&svc_pool_map_mutex);
 79         return err;
 80 }
 81 
 82 static int
 83 param_get_pool_mode(char *buf, struct kernel_param *kp)
 84 {
 85         int *ip = (int *)kp->arg;
 86 
 87         switch (*ip)
 88         {
 89         case SVC_POOL_AUTO:
 90                 return strlcpy(buf, "auto", 20);
 91         case SVC_POOL_GLOBAL:
 92                 return strlcpy(buf, "global", 20);
 93         case SVC_POOL_PERCPU:
 94                 return strlcpy(buf, "percpu", 20);
 95         case SVC_POOL_PERNODE:
 96                 return strlcpy(buf, "pernode", 20);
 97         default:
 98                 return sprintf(buf, "%d", *ip);
 99         }
100 }
101 
102 module_param_call(pool_mode, param_set_pool_mode, param_get_pool_mode,
103                  &svc_pool_map.mode, 0644);
104 
105 /*
106  * Detect best pool mapping mode heuristically,
107  * according to the machine's topology.
108  */
109 static int
110 svc_pool_map_choose_mode(void)
111 {
112         unsigned int node;
113 
114         if (nr_online_nodes > 1) {
115                 /*
116                  * Actually have multiple NUMA nodes,
117                  * so split pools on NUMA node boundaries
118                  */
119                 return SVC_POOL_PERNODE;
120         }
121 
122         node = first_online_node;
123         if (nr_cpus_node(node) > 2) {
124                 /*
125                  * Non-trivial SMP, or CONFIG_NUMA on
126                  * non-NUMA hardware, e.g. with a generic
127                  * x86_64 kernel on Xeons.  In this case we
128                  * want to divide the pools on cpu boundaries.
129                  */
130                 return SVC_POOL_PERCPU;
131         }
132 
133         /* default: one global pool */
134         return SVC_POOL_GLOBAL;
135 }
136 
137 /*
138  * Allocate the to_pool[] and pool_to[] arrays.
139  * Returns 0 on success or an errno.
140  */
141 static int
142 svc_pool_map_alloc_arrays(struct svc_pool_map *m, unsigned int maxpools)
143 {
144         m->to_pool = kcalloc(maxpools, sizeof(unsigned int), GFP_KERNEL);
145         if (!m->to_pool)
146                 goto fail;
147         m->pool_to = kcalloc(maxpools, sizeof(unsigned int), GFP_KERNEL);
148         if (!m->pool_to)
149                 goto fail_free;
150 
151         return 0;
152 
153 fail_free:
154         kfree(m->to_pool);
155         m->to_pool = NULL;
156 fail:
157         return -ENOMEM;
158 }
159 
160 /*
161  * Initialise the pool map for SVC_POOL_PERCPU mode.
162  * Returns number of pools or <0 on error.
163  */
164 static int
165 svc_pool_map_init_percpu(struct svc_pool_map *m)
166 {
167         unsigned int maxpools = nr_cpu_ids;
168         unsigned int pidx = 0;
169         unsigned int cpu;
170         int err;
171 
172         err = svc_pool_map_alloc_arrays(m, maxpools);
173         if (err)
174                 return err;
175 
176         for_each_online_cpu(cpu) {
177                 BUG_ON(pidx >= maxpools);
178                 m->to_pool[cpu] = pidx;
179                 m->pool_to[pidx] = cpu;
180                 pidx++;
181         }
182         /* cpus brought online later all get mapped to pool0, sorry */
183 
184         return pidx;
185 };
186 
187 
188 /*
189  * Initialise the pool map for SVC_POOL_PERNODE mode.
190  * Returns number of pools or <0 on error.
191  */
192 static int
193 svc_pool_map_init_pernode(struct svc_pool_map *m)
194 {
195         unsigned int maxpools = nr_node_ids;
196         unsigned int pidx = 0;
197         unsigned int node;
198         int err;
199 
200         err = svc_pool_map_alloc_arrays(m, maxpools);
201         if (err)
202                 return err;
203 
204         for_each_node_with_cpus(node) {
205                 /* some architectures (e.g. SN2) have cpuless nodes */
206                 BUG_ON(pidx > maxpools);
207                 m->to_pool[node] = pidx;
208                 m->pool_to[pidx] = node;
209                 pidx++;
210         }
211         /* nodes brought online later all get mapped to pool0, sorry */
212 
213         return pidx;
214 }
215 
216 
217 /*
218  * Add a reference to the global map of cpus to pools (and
219  * vice versa).  Initialise the map if we're the first user.
220  * Returns the number of pools.
221  */
222 unsigned int
223 svc_pool_map_get(void)
224 {
225         struct svc_pool_map *m = &svc_pool_map;
226         int npools = -1;
227 
228         mutex_lock(&svc_pool_map_mutex);
229 
230         if (m->count++) {
231                 mutex_unlock(&svc_pool_map_mutex);
232                 return m->npools;
233         }
234 
235         if (m->mode == SVC_POOL_AUTO)
236                 m->mode = svc_pool_map_choose_mode();
237 
238         switch (m->mode) {
239         case SVC_POOL_PERCPU:
240                 npools = svc_pool_map_init_percpu(m);
241                 break;
242         case SVC_POOL_PERNODE:
243                 npools = svc_pool_map_init_pernode(m);
244                 break;
245         }
246 
247         if (npools < 0) {
248                 /* default, or memory allocation failure */
249                 npools = 1;
250                 m->mode = SVC_POOL_GLOBAL;
251         }
252         m->npools = npools;
253 
254         mutex_unlock(&svc_pool_map_mutex);
255         return m->npools;
256 }
257 EXPORT_SYMBOL_GPL(svc_pool_map_get);
258 
259 /*
260  * Drop a reference to the global map of cpus to pools.
261  * When the last reference is dropped, the map data is
262  * freed; this allows the sysadmin to change the pool
263  * mode using the pool_mode module option without
264  * rebooting or re-loading sunrpc.ko.
265  */
266 void
267 svc_pool_map_put(void)
268 {
269         struct svc_pool_map *m = &svc_pool_map;
270 
271         mutex_lock(&svc_pool_map_mutex);
272 
273         if (!--m->count) {
274                 kfree(m->to_pool);
275                 m->to_pool = NULL;
276                 kfree(m->pool_to);
277                 m->pool_to = NULL;
278                 m->npools = 0;
279         }
280 
281         mutex_unlock(&svc_pool_map_mutex);
282 }
283 EXPORT_SYMBOL_GPL(svc_pool_map_put);
284 
285 static int svc_pool_map_get_node(unsigned int pidx)
286 {
287         const struct svc_pool_map *m = &svc_pool_map;
288 
289         if (m->count) {
290                 if (m->mode == SVC_POOL_PERCPU)
291                         return cpu_to_node(m->pool_to[pidx]);
292                 if (m->mode == SVC_POOL_PERNODE)
293                         return m->pool_to[pidx];
294         }
295         return NUMA_NO_NODE;
296 }
297 /*
298  * Set the given thread's cpus_allowed mask so that it
299  * will only run on cpus in the given pool.
300  */
301 static inline void
302 svc_pool_map_set_cpumask(struct task_struct *task, unsigned int pidx)
303 {
304         struct svc_pool_map *m = &svc_pool_map;
305         unsigned int node = m->pool_to[pidx];
306 
307         /*
308          * The caller checks for sv_nrpools > 1, which
309          * implies that we've been initialized.
310          */
311         WARN_ON_ONCE(m->count == 0);
312         if (m->count == 0)
313                 return;
314 
315         switch (m->mode) {
316         case SVC_POOL_PERCPU:
317         {
318                 set_cpus_allowed_ptr(task, cpumask_of(node));
319                 break;
320         }
321         case SVC_POOL_PERNODE:
322         {
323                 set_cpus_allowed_ptr(task, cpumask_of_node(node));
324                 break;
325         }
326         }
327 }
328 
329 /*
330  * Use the mapping mode to choose a pool for a given CPU.
331  * Used when enqueueing an incoming RPC.  Always returns
332  * a non-NULL pool pointer.
333  */
334 struct svc_pool *
335 svc_pool_for_cpu(struct svc_serv *serv, int cpu)
336 {
337         struct svc_pool_map *m = &svc_pool_map;
338         unsigned int pidx = 0;
339 
340         /*
341          * An uninitialised map happens in a pure client when
342          * lockd is brought up, so silently treat it the
343          * same as SVC_POOL_GLOBAL.
344          */
345         if (svc_serv_is_pooled(serv)) {
346                 switch (m->mode) {
347                 case SVC_POOL_PERCPU:
348                         pidx = m->to_pool[cpu];
349                         break;
350                 case SVC_POOL_PERNODE:
351                         pidx = m->to_pool[cpu_to_node(cpu)];
352                         break;
353                 }
354         }
355         return &serv->sv_pools[pidx % serv->sv_nrpools];
356 }
357 
358 int svc_rpcb_setup(struct svc_serv *serv, struct net *net)
359 {
360         int err;
361 
362         err = rpcb_create_local(net);
363         if (err)
364                 return err;
365 
366         /* Remove any stale portmap registrations */
367         svc_unregister(serv, net);
368         return 0;
369 }
370 EXPORT_SYMBOL_GPL(svc_rpcb_setup);
371 
372 void svc_rpcb_cleanup(struct svc_serv *serv, struct net *net)
373 {
374         svc_unregister(serv, net);
375         rpcb_put_local(net);
376 }
377 EXPORT_SYMBOL_GPL(svc_rpcb_cleanup);
378 
379 static int svc_uses_rpcbind(struct svc_serv *serv)
380 {
381         struct svc_program      *progp;
382         unsigned int            i;
383 
384         for (progp = serv->sv_program; progp; progp = progp->pg_next) {
385                 for (i = 0; i < progp->pg_nvers; i++) {
386                         if (progp->pg_vers[i] == NULL)
387                                 continue;
388                         if (progp->pg_vers[i]->vs_hidden == 0)
389                                 return 1;
390                 }
391         }
392 
393         return 0;
394 }
395 
396 int svc_bind(struct svc_serv *serv, struct net *net)
397 {
398         if (!svc_uses_rpcbind(serv))
399                 return 0;
400         return svc_rpcb_setup(serv, net);
401 }
402 EXPORT_SYMBOL_GPL(svc_bind);
403 
404 /*
405  * Create an RPC service
406  */
407 static struct svc_serv *
408 __svc_create(struct svc_program *prog, unsigned int bufsize, int npools,
409              struct svc_serv_ops *ops)
410 {
411         struct svc_serv *serv;
412         unsigned int vers;
413         unsigned int xdrsize;
414         unsigned int i;
415 
416         if (!(serv = kzalloc(sizeof(*serv), GFP_KERNEL)))
417                 return NULL;
418         serv->sv_name      = prog->pg_name;
419         serv->sv_program   = prog;
420         serv->sv_nrthreads = 1;
421         serv->sv_stats     = prog->pg_stats;
422         if (bufsize > RPCSVC_MAXPAYLOAD)
423                 bufsize = RPCSVC_MAXPAYLOAD;
424         serv->sv_max_payload = bufsize? bufsize : 4096;
425         serv->sv_max_mesg  = roundup(serv->sv_max_payload + PAGE_SIZE, PAGE_SIZE);
426         serv->sv_ops = ops;
427         xdrsize = 0;
428         while (prog) {
429                 prog->pg_lovers = prog->pg_nvers-1;
430                 for (vers=0; vers<prog->pg_nvers ; vers++)
431                         if (prog->pg_vers[vers]) {
432                                 prog->pg_hivers = vers;
433                                 if (prog->pg_lovers > vers)
434                                         prog->pg_lovers = vers;
435                                 if (prog->pg_vers[vers]->vs_xdrsize > xdrsize)
436                                         xdrsize = prog->pg_vers[vers]->vs_xdrsize;
437                         }
438                 prog = prog->pg_next;
439         }
440         serv->sv_xdrsize   = xdrsize;
441         INIT_LIST_HEAD(&serv->sv_tempsocks);
442         INIT_LIST_HEAD(&serv->sv_permsocks);
443         init_timer(&serv->sv_temptimer);
444         spin_lock_init(&serv->sv_lock);
445 
446         serv->sv_nrpools = npools;
447         serv->sv_pools =
448                 kcalloc(serv->sv_nrpools, sizeof(struct svc_pool),
449                         GFP_KERNEL);
450         if (!serv->sv_pools) {
451                 kfree(serv);
452                 return NULL;
453         }
454 
455         for (i = 0; i < serv->sv_nrpools; i++) {
456                 struct svc_pool *pool = &serv->sv_pools[i];
457 
458                 dprintk("svc: initialising pool %u for %s\n",
459                                 i, serv->sv_name);
460 
461                 pool->sp_id = i;
462                 INIT_LIST_HEAD(&pool->sp_sockets);
463                 INIT_LIST_HEAD(&pool->sp_all_threads);
464                 spin_lock_init(&pool->sp_lock);
465         }
466 
467         return serv;
468 }
469 
470 struct svc_serv *
471 svc_create(struct svc_program *prog, unsigned int bufsize,
472            struct svc_serv_ops *ops)
473 {
474         return __svc_create(prog, bufsize, /*npools*/1, ops);
475 }
476 EXPORT_SYMBOL_GPL(svc_create);
477 
478 struct svc_serv *
479 svc_create_pooled(struct svc_program *prog, unsigned int bufsize,
480                   struct svc_serv_ops *ops)
481 {
482         struct svc_serv *serv;
483         unsigned int npools = svc_pool_map_get();
484 
485         serv = __svc_create(prog, bufsize, npools, ops);
486         if (!serv)
487                 goto out_err;
488         return serv;
489 out_err:
490         svc_pool_map_put();
491         return NULL;
492 }
493 EXPORT_SYMBOL_GPL(svc_create_pooled);
494 
495 void svc_shutdown_net(struct svc_serv *serv, struct net *net)
496 {
497         svc_close_net(serv, net);
498 
499         if (serv->sv_ops->svo_shutdown)
500                 serv->sv_ops->svo_shutdown(serv, net);
501 }
502 EXPORT_SYMBOL_GPL(svc_shutdown_net);
503 
504 /*
505  * Destroy an RPC service. Should be called with appropriate locking to
506  * protect the sv_nrthreads, sv_permsocks and sv_tempsocks.
507  */
508 void
509 svc_destroy(struct svc_serv *serv)
510 {
511         dprintk("svc: svc_destroy(%s, %d)\n",
512                                 serv->sv_program->pg_name,
513                                 serv->sv_nrthreads);
514 
515         if (serv->sv_nrthreads) {
516                 if (--(serv->sv_nrthreads) != 0) {
517                         svc_sock_update_bufs(serv);
518                         return;
519                 }
520         } else
521                 printk("svc_destroy: no threads for serv=%p!\n", serv);
522 
523         del_timer_sync(&serv->sv_temptimer);
524 
525         /*
526          * The last user is gone and thus all sockets have to be destroyed to
527          * the point. Check this.
528          */
529         BUG_ON(!list_empty(&serv->sv_permsocks));
530         BUG_ON(!list_empty(&serv->sv_tempsocks));
531 
532         cache_clean_deferred(serv);
533 
534         if (svc_serv_is_pooled(serv))
535                 svc_pool_map_put();
536 
537         kfree(serv->sv_pools);
538         kfree(serv);
539 }
540 EXPORT_SYMBOL_GPL(svc_destroy);
541 
542 /*
543  * Allocate an RPC server's buffer space.
544  * We allocate pages and place them in rq_argpages.
545  */
546 static int
547 svc_init_buffer(struct svc_rqst *rqstp, unsigned int size, int node)
548 {
549         unsigned int pages, arghi;
550 
551         /* bc_xprt uses fore channel allocated buffers */
552         if (svc_is_backchannel(rqstp))
553                 return 1;
554 
555         pages = size / PAGE_SIZE + 1; /* extra page as we hold both request and reply.
556                                        * We assume one is at most one page
557                                        */
558         arghi = 0;
559         WARN_ON_ONCE(pages > RPCSVC_MAXPAGES);
560         if (pages > RPCSVC_MAXPAGES)
561                 pages = RPCSVC_MAXPAGES;
562         while (pages) {
563                 struct page *p = alloc_pages_node(node, GFP_KERNEL, 0);
564                 if (!p)
565                         break;
566                 rqstp->rq_pages[arghi++] = p;
567                 pages--;
568         }
569         return pages == 0;
570 }
571 
572 /*
573  * Release an RPC server buffer
574  */
575 static void
576 svc_release_buffer(struct svc_rqst *rqstp)
577 {
578         unsigned int i;
579 
580         for (i = 0; i < ARRAY_SIZE(rqstp->rq_pages); i++)
581                 if (rqstp->rq_pages[i])
582                         put_page(rqstp->rq_pages[i]);
583 }
584 
585 struct svc_rqst *
586 svc_rqst_alloc(struct svc_serv *serv, struct svc_pool *pool, int node)
587 {
588         struct svc_rqst *rqstp;
589 
590         rqstp = kzalloc_node(sizeof(*rqstp), GFP_KERNEL, node);
591         if (!rqstp)
592                 return rqstp;
593 
594         __set_bit(RQ_BUSY, &rqstp->rq_flags);
595         spin_lock_init(&rqstp->rq_lock);
596         rqstp->rq_server = serv;
597         rqstp->rq_pool = pool;
598 
599         rqstp->rq_argp = kmalloc_node(serv->sv_xdrsize, GFP_KERNEL, node);
600         if (!rqstp->rq_argp)
601                 goto out_enomem;
602 
603         rqstp->rq_resp = kmalloc_node(serv->sv_xdrsize, GFP_KERNEL, node);
604         if (!rqstp->rq_resp)
605                 goto out_enomem;
606 
607         if (!svc_init_buffer(rqstp, serv->sv_max_mesg, node))
608                 goto out_enomem;
609 
610         return rqstp;
611 out_enomem:
612         svc_rqst_free(rqstp);
613         return NULL;
614 }
615 EXPORT_SYMBOL_GPL(svc_rqst_alloc);
616 
617 struct svc_rqst *
618 svc_prepare_thread(struct svc_serv *serv, struct svc_pool *pool, int node)
619 {
620         struct svc_rqst *rqstp;
621 
622         rqstp = svc_rqst_alloc(serv, pool, node);
623         if (!rqstp)
624                 return ERR_PTR(-ENOMEM);
625 
626         serv->sv_nrthreads++;
627         spin_lock_bh(&pool->sp_lock);
628         pool->sp_nrthreads++;
629         list_add_rcu(&rqstp->rq_all, &pool->sp_all_threads);
630         spin_unlock_bh(&pool->sp_lock);
631         return rqstp;
632 }
633 EXPORT_SYMBOL_GPL(svc_prepare_thread);
634 
635 /*
636  * Choose a pool in which to create a new thread, for svc_set_num_threads
637  */
638 static inline struct svc_pool *
639 choose_pool(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
640 {
641         if (pool != NULL)
642                 return pool;
643 
644         return &serv->sv_pools[(*state)++ % serv->sv_nrpools];
645 }
646 
647 /*
648  * Choose a thread to kill, for svc_set_num_threads
649  */
650 static inline struct task_struct *
651 choose_victim(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
652 {
653         unsigned int i;
654         struct task_struct *task = NULL;
655 
656         if (pool != NULL) {
657                 spin_lock_bh(&pool->sp_lock);
658         } else {
659                 /* choose a pool in round-robin fashion */
660                 for (i = 0; i < serv->sv_nrpools; i++) {
661                         pool = &serv->sv_pools[--(*state) % serv->sv_nrpools];
662                         spin_lock_bh(&pool->sp_lock);
663                         if (!list_empty(&pool->sp_all_threads))
664                                 goto found_pool;
665                         spin_unlock_bh(&pool->sp_lock);
666                 }
667                 return NULL;
668         }
669 
670 found_pool:
671         if (!list_empty(&pool->sp_all_threads)) {
672                 struct svc_rqst *rqstp;
673 
674                 /*
675                  * Remove from the pool->sp_all_threads list
676                  * so we don't try to kill it again.
677                  */
678                 rqstp = list_entry(pool->sp_all_threads.next, struct svc_rqst, rq_all);
679                 set_bit(RQ_VICTIM, &rqstp->rq_flags);
680                 list_del_rcu(&rqstp->rq_all);
681                 task = rqstp->rq_task;
682         }
683         spin_unlock_bh(&pool->sp_lock);
684 
685         return task;
686 }
687 
688 /*
689  * Create or destroy enough new threads to make the number
690  * of threads the given number.  If `pool' is non-NULL, applies
691  * only to threads in that pool, otherwise round-robins between
692  * all pools.  Caller must ensure that mutual exclusion between this and
693  * server startup or shutdown.
694  *
695  * Destroying threads relies on the service threads filling in
696  * rqstp->rq_task, which only the nfs ones do.  Assumes the serv
697  * has been created using svc_create_pooled().
698  *
699  * Based on code that used to be in nfsd_svc() but tweaked
700  * to be pool-aware.
701  */
702 int
703 svc_set_num_threads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
704 {
705         struct svc_rqst *rqstp;
706         struct task_struct *task;
707         struct svc_pool *chosen_pool;
708         int error = 0;
709         unsigned int state = serv->sv_nrthreads-1;
710         int node;
711 
712         if (pool == NULL) {
713                 /* The -1 assumes caller has done a svc_get() */
714                 nrservs -= (serv->sv_nrthreads-1);
715         } else {
716                 spin_lock_bh(&pool->sp_lock);
717                 nrservs -= pool->sp_nrthreads;
718                 spin_unlock_bh(&pool->sp_lock);
719         }
720 
721         /* create new threads */
722         while (nrservs > 0) {
723                 nrservs--;
724                 chosen_pool = choose_pool(serv, pool, &state);
725 
726                 node = svc_pool_map_get_node(chosen_pool->sp_id);
727                 rqstp = svc_prepare_thread(serv, chosen_pool, node);
728                 if (IS_ERR(rqstp)) {
729                         error = PTR_ERR(rqstp);
730                         break;
731                 }
732 
733                 __module_get(serv->sv_ops->svo_module);
734                 task = kthread_create_on_node(serv->sv_ops->svo_function, rqstp,
735                                               node, "%s", serv->sv_name);
736                 if (IS_ERR(task)) {
737                         error = PTR_ERR(task);
738                         module_put(serv->sv_ops->svo_module);
739                         svc_exit_thread(rqstp);
740                         break;
741                 }
742 
743                 rqstp->rq_task = task;
744                 if (serv->sv_nrpools > 1)
745                         svc_pool_map_set_cpumask(task, chosen_pool->sp_id);
746 
747                 svc_sock_update_bufs(serv);
748                 wake_up_process(task);
749         }
750         /* destroy old threads */
751         while (nrservs < 0 &&
752                (task = choose_victim(serv, pool, &state)) != NULL) {
753                 send_sig(SIGINT, task, 1);
754                 nrservs++;
755         }
756 
757         return error;
758 }
759 EXPORT_SYMBOL_GPL(svc_set_num_threads);
760 
761 /*
762  * Called from a server thread as it's exiting. Caller must hold the "service
763  * mutex" for the service.
764  */
765 void
766 svc_rqst_free(struct svc_rqst *rqstp)
767 {
768         svc_release_buffer(rqstp);
769         kfree(rqstp->rq_resp);
770         kfree(rqstp->rq_argp);
771         kfree(rqstp->rq_auth_data);
772         kfree_rcu(rqstp, rq_rcu_head);
773 }
774 EXPORT_SYMBOL_GPL(svc_rqst_free);
775 
776 void
777 svc_exit_thread(struct svc_rqst *rqstp)
778 {
779         struct svc_serv *serv = rqstp->rq_server;
780         struct svc_pool *pool = rqstp->rq_pool;
781 
782         spin_lock_bh(&pool->sp_lock);
783         pool->sp_nrthreads--;
784         if (!test_and_set_bit(RQ_VICTIM, &rqstp->rq_flags))
785                 list_del_rcu(&rqstp->rq_all);
786         spin_unlock_bh(&pool->sp_lock);
787 
788         svc_rqst_free(rqstp);
789 
790         /* Release the server */
791         if (serv)
792                 svc_destroy(serv);
793 }
794 EXPORT_SYMBOL_GPL(svc_exit_thread);
795 
796 /*
797  * Register an "inet" protocol family netid with the local
798  * rpcbind daemon via an rpcbind v4 SET request.
799  *
800  * No netconfig infrastructure is available in the kernel, so
801  * we map IP_ protocol numbers to netids by hand.
802  *
803  * Returns zero on success; a negative errno value is returned
804  * if any error occurs.
805  */
806 static int __svc_rpcb_register4(struct net *net, const u32 program,
807                                 const u32 version,
808                                 const unsigned short protocol,
809                                 const unsigned short port)
810 {
811         const struct sockaddr_in sin = {
812                 .sin_family             = AF_INET,
813                 .sin_addr.s_addr        = htonl(INADDR_ANY),
814                 .sin_port               = htons(port),
815         };
816         const char *netid;
817         int error;
818 
819         switch (protocol) {
820         case IPPROTO_UDP:
821                 netid = RPCBIND_NETID_UDP;
822                 break;
823         case IPPROTO_TCP:
824                 netid = RPCBIND_NETID_TCP;
825                 break;
826         default:
827                 return -ENOPROTOOPT;
828         }
829 
830         error = rpcb_v4_register(net, program, version,
831                                         (const struct sockaddr *)&sin, netid);
832 
833         /*
834          * User space didn't support rpcbind v4, so retry this
835          * registration request with the legacy rpcbind v2 protocol.
836          */
837         if (error == -EPROTONOSUPPORT)
838                 error = rpcb_register(net, program, version, protocol, port);
839 
840         return error;
841 }
842 
843 #if IS_ENABLED(CONFIG_IPV6)
844 /*
845  * Register an "inet6" protocol family netid with the local
846  * rpcbind daemon via an rpcbind v4 SET request.
847  *
848  * No netconfig infrastructure is available in the kernel, so
849  * we map IP_ protocol numbers to netids by hand.
850  *
851  * Returns zero on success; a negative errno value is returned
852  * if any error occurs.
853  */
854 static int __svc_rpcb_register6(struct net *net, const u32 program,
855                                 const u32 version,
856                                 const unsigned short protocol,
857                                 const unsigned short port)
858 {
859         const struct sockaddr_in6 sin6 = {
860                 .sin6_family            = AF_INET6,
861                 .sin6_addr              = IN6ADDR_ANY_INIT,
862                 .sin6_port              = htons(port),
863         };
864         const char *netid;
865         int error;
866 
867         switch (protocol) {
868         case IPPROTO_UDP:
869                 netid = RPCBIND_NETID_UDP6;
870                 break;
871         case IPPROTO_TCP:
872                 netid = RPCBIND_NETID_TCP6;
873                 break;
874         default:
875                 return -ENOPROTOOPT;
876         }
877 
878         error = rpcb_v4_register(net, program, version,
879                                         (const struct sockaddr *)&sin6, netid);
880 
881         /*
882          * User space didn't support rpcbind version 4, so we won't
883          * use a PF_INET6 listener.
884          */
885         if (error == -EPROTONOSUPPORT)
886                 error = -EAFNOSUPPORT;
887 
888         return error;
889 }
890 #endif  /* IS_ENABLED(CONFIG_IPV6) */
891 
892 /*
893  * Register a kernel RPC service via rpcbind version 4.
894  *
895  * Returns zero on success; a negative errno value is returned
896  * if any error occurs.
897  */
898 static int __svc_register(struct net *net, const char *progname,
899                           const u32 program, const u32 version,
900                           const int family,
901                           const unsigned short protocol,
902                           const unsigned short port)
903 {
904         int error = -EAFNOSUPPORT;
905 
906         switch (family) {
907         case PF_INET:
908                 error = __svc_rpcb_register4(net, program, version,
909                                                 protocol, port);
910                 break;
911 #if IS_ENABLED(CONFIG_IPV6)
912         case PF_INET6:
913                 error = __svc_rpcb_register6(net, program, version,
914                                                 protocol, port);
915 #endif
916         }
917 
918         return error;
919 }
920 
921 /**
922  * svc_register - register an RPC service with the local portmapper
923  * @serv: svc_serv struct for the service to register
924  * @net: net namespace for the service to register
925  * @family: protocol family of service's listener socket
926  * @proto: transport protocol number to advertise
927  * @port: port to advertise
928  *
929  * Service is registered for any address in the passed-in protocol family
930  */
931 int svc_register(const struct svc_serv *serv, struct net *net,
932                  const int family, const unsigned short proto,
933                  const unsigned short port)
934 {
935         struct svc_program      *progp;
936         struct svc_version      *vers;
937         unsigned int            i;
938         int                     error = 0;
939 
940         WARN_ON_ONCE(proto == 0 && port == 0);
941         if (proto == 0 && port == 0)
942                 return -EINVAL;
943 
944         for (progp = serv->sv_program; progp; progp = progp->pg_next) {
945                 for (i = 0; i < progp->pg_nvers; i++) {
946                         vers = progp->pg_vers[i];
947                         if (vers == NULL)
948                                 continue;
949 
950                         dprintk("svc: svc_register(%sv%d, %s, %u, %u)%s\n",
951                                         progp->pg_name,
952                                         i,
953                                         proto == IPPROTO_UDP?  "udp" : "tcp",
954                                         port,
955                                         family,
956                                         vers->vs_hidden ?
957                                         " (but not telling portmap)" : "");
958 
959                         if (vers->vs_hidden)
960                                 continue;
961 
962                         error = __svc_register(net, progp->pg_name, progp->pg_prog,
963                                                 i, family, proto, port);
964 
965                         if (vers->vs_rpcb_optnl) {
966                                 error = 0;
967                                 continue;
968                         }
969 
970                         if (error < 0) {
971                                 printk(KERN_WARNING "svc: failed to register "
972                                         "%sv%u RPC service (errno %d).\n",
973                                         progp->pg_name, i, -error);
974                                 break;
975                         }
976                 }
977         }
978 
979         return error;
980 }
981 
982 /*
983  * If user space is running rpcbind, it should take the v4 UNSET
984  * and clear everything for this [program, version].  If user space
985  * is running portmap, it will reject the v4 UNSET, but won't have
986  * any "inet6" entries anyway.  So a PMAP_UNSET should be sufficient
987  * in this case to clear all existing entries for [program, version].
988  */
989 static void __svc_unregister(struct net *net, const u32 program, const u32 version,
990                              const char *progname)
991 {
992         int error;
993 
994         error = rpcb_v4_register(net, program, version, NULL, "");
995 
996         /*
997          * User space didn't support rpcbind v4, so retry this
998          * request with the legacy rpcbind v2 protocol.
999          */
1000         if (error == -EPROTONOSUPPORT)
1001                 error = rpcb_register(net, program, version, 0, 0);
1002 
1003         dprintk("svc: %s(%sv%u), error %d\n",
1004                         __func__, progname, version, error);
1005 }
1006 
1007 /*
1008  * All netids, bind addresses and ports registered for [program, version]
1009  * are removed from the local rpcbind database (if the service is not
1010  * hidden) to make way for a new instance of the service.
1011  *
1012  * The result of unregistration is reported via dprintk for those who want
1013  * verification of the result, but is otherwise not important.
1014  */
1015 static void svc_unregister(const struct svc_serv *serv, struct net *net)
1016 {
1017         struct svc_program *progp;
1018         unsigned long flags;
1019         unsigned int i;
1020 
1021         clear_thread_flag(TIF_SIGPENDING);
1022 
1023         for (progp = serv->sv_program; progp; progp = progp->pg_next) {
1024                 for (i = 0; i < progp->pg_nvers; i++) {
1025                         if (progp->pg_vers[i] == NULL)
1026                                 continue;
1027                         if (progp->pg_vers[i]->vs_hidden)
1028                                 continue;
1029 
1030                         dprintk("svc: attempting to unregister %sv%u\n",
1031                                 progp->pg_name, i);
1032                         __svc_unregister(net, progp->pg_prog, i, progp->pg_name);
1033                 }
1034         }
1035 
1036         spin_lock_irqsave(&current->sighand->siglock, flags);
1037         recalc_sigpending();
1038         spin_unlock_irqrestore(&current->sighand->siglock, flags);
1039 }
1040 
1041 /*
1042  * dprintk the given error with the address of the client that caused it.
1043  */
1044 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
1045 static __printf(2, 3)
1046 void svc_printk(struct svc_rqst *rqstp, const char *fmt, ...)
1047 {
1048         struct va_format vaf;
1049         va_list args;
1050         char    buf[RPC_MAX_ADDRBUFLEN];
1051 
1052         va_start(args, fmt);
1053 
1054         vaf.fmt = fmt;
1055         vaf.va = &args;
1056 
1057         dprintk("svc: %s: %pV", svc_print_addr(rqstp, buf, sizeof(buf)), &vaf);
1058 
1059         va_end(args);
1060 }
1061 #else
1062 static __printf(2,3) void svc_printk(struct svc_rqst *rqstp, const char *fmt, ...) {}
1063 #endif
1064 
1065 /*
1066  * Common routine for processing the RPC request.
1067  */
1068 static int
1069 svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
1070 {
1071         struct svc_program      *progp;
1072         struct svc_version      *versp = NULL;  /* compiler food */
1073         struct svc_procedure    *procp = NULL;
1074         struct svc_serv         *serv = rqstp->rq_server;
1075         kxdrproc_t              xdr;
1076         __be32                  *statp;
1077         u32                     prog, vers, proc;
1078         __be32                  auth_stat, rpc_stat;
1079         int                     auth_res;
1080         __be32                  *reply_statp;
1081 
1082         rpc_stat = rpc_success;
1083 
1084         if (argv->iov_len < 6*4)
1085                 goto err_short_len;
1086 
1087         /* Will be turned off only in gss privacy case: */
1088         set_bit(RQ_SPLICE_OK, &rqstp->rq_flags);
1089         /* Will be turned off only when NFSv4 Sessions are used */
1090         set_bit(RQ_USEDEFERRAL, &rqstp->rq_flags);
1091         clear_bit(RQ_DROPME, &rqstp->rq_flags);
1092 
1093         /* Setup reply header */
1094         rqstp->rq_xprt->xpt_ops->xpo_prep_reply_hdr(rqstp);
1095 
1096         svc_putu32(resv, rqstp->rq_xid);
1097 
1098         vers = svc_getnl(argv);
1099 
1100         /* First words of reply: */
1101         svc_putnl(resv, 1);             /* REPLY */
1102 
1103         if (vers != 2)          /* RPC version number */
1104                 goto err_bad_rpc;
1105 
1106         /* Save position in case we later decide to reject: */
1107         reply_statp = resv->iov_base + resv->iov_len;
1108 
1109         svc_putnl(resv, 0);             /* ACCEPT */
1110 
1111         rqstp->rq_prog = prog = svc_getnl(argv);        /* program number */
1112         rqstp->rq_vers = vers = svc_getnl(argv);        /* version number */
1113         rqstp->rq_proc = proc = svc_getnl(argv);        /* procedure number */
1114 
1115         for (progp = serv->sv_program; progp; progp = progp->pg_next)
1116                 if (prog == progp->pg_prog)
1117                         break;
1118 
1119         /*
1120          * Decode auth data, and add verifier to reply buffer.
1121          * We do this before anything else in order to get a decent
1122          * auth verifier.
1123          */
1124         auth_res = svc_authenticate(rqstp, &auth_stat);
1125         /* Also give the program a chance to reject this call: */
1126         if (auth_res == SVC_OK && progp) {
1127                 auth_stat = rpc_autherr_badcred;
1128                 auth_res = progp->pg_authenticate(rqstp);
1129         }
1130         switch (auth_res) {
1131         case SVC_OK:
1132                 break;
1133         case SVC_GARBAGE:
1134                 goto err_garbage;
1135         case SVC_SYSERR:
1136                 rpc_stat = rpc_system_err;
1137                 goto err_bad;
1138         case SVC_DENIED:
1139                 goto err_bad_auth;
1140         case SVC_CLOSE:
1141                 if (test_bit(XPT_TEMP, &rqstp->rq_xprt->xpt_flags))
1142                         svc_close_xprt(rqstp->rq_xprt);
1143         case SVC_DROP:
1144                 goto dropit;
1145         case SVC_COMPLETE:
1146                 goto sendit;
1147         }
1148 
1149         if (progp == NULL)
1150                 goto err_bad_prog;
1151 
1152         if (vers >= progp->pg_nvers ||
1153           !(versp = progp->pg_vers[vers]))
1154                 goto err_bad_vers;
1155 
1156         procp = versp->vs_proc + proc;
1157         if (proc >= versp->vs_nproc || !procp->pc_func)
1158                 goto err_bad_proc;
1159         rqstp->rq_procinfo = procp;
1160 
1161         /* Syntactic check complete */
1162         serv->sv_stats->rpccnt++;
1163 
1164         /* Build the reply header. */
1165         statp = resv->iov_base +resv->iov_len;
1166         svc_putnl(resv, RPC_SUCCESS);
1167 
1168         /* Bump per-procedure stats counter */
1169         procp->pc_count++;
1170 
1171         /* Initialize storage for argp and resp */
1172         memset(rqstp->rq_argp, 0, procp->pc_argsize);
1173         memset(rqstp->rq_resp, 0, procp->pc_ressize);
1174 
1175         /* un-reserve some of the out-queue now that we have a
1176          * better idea of reply size
1177          */
1178         if (procp->pc_xdrressize)
1179                 svc_reserve_auth(rqstp, procp->pc_xdrressize<<2);
1180 
1181         /* Call the function that processes the request. */
1182         if (!versp->vs_dispatch) {
1183                 /* Decode arguments */
1184                 xdr = procp->pc_decode;
1185                 if (xdr && !xdr(rqstp, argv->iov_base, rqstp->rq_argp))
1186                         goto err_garbage;
1187 
1188                 *statp = procp->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
1189 
1190                 /* Encode reply */
1191                 if (test_bit(RQ_DROPME, &rqstp->rq_flags)) {
1192                         if (procp->pc_release)
1193                                 procp->pc_release(rqstp, NULL, rqstp->rq_resp);
1194                         goto dropit;
1195                 }
1196                 if (*statp == rpc_success &&
1197                     (xdr = procp->pc_encode) &&
1198                     !xdr(rqstp, resv->iov_base+resv->iov_len, rqstp->rq_resp)) {
1199                         dprintk("svc: failed to encode reply\n");
1200                         /* serv->sv_stats->rpcsystemerr++; */
1201                         *statp = rpc_system_err;
1202                 }
1203         } else {
1204                 dprintk("svc: calling dispatcher\n");
1205                 if (!versp->vs_dispatch(rqstp, statp)) {
1206                         /* Release reply info */
1207                         if (procp->pc_release)
1208                                 procp->pc_release(rqstp, NULL, rqstp->rq_resp);
1209                         goto dropit;
1210                 }
1211         }
1212 
1213         /* Check RPC status result */
1214         if (*statp != rpc_success)
1215                 resv->iov_len = ((void*)statp)  - resv->iov_base + 4;
1216 
1217         /* Release reply info */
1218         if (procp->pc_release)
1219                 procp->pc_release(rqstp, NULL, rqstp->rq_resp);
1220 
1221         if (procp->pc_encode == NULL)
1222                 goto dropit;
1223 
1224  sendit:
1225         if (svc_authorise(rqstp))
1226                 goto dropit;
1227         return 1;               /* Caller can now send it */
1228 
1229  dropit:
1230         svc_authorise(rqstp);   /* doesn't hurt to call this twice */
1231         dprintk("svc: svc_process dropit\n");
1232         return 0;
1233 
1234 err_short_len:
1235         svc_printk(rqstp, "short len %Zd, dropping request\n",
1236                         argv->iov_len);
1237 
1238         goto dropit;                    /* drop request */
1239 
1240 err_bad_rpc:
1241         serv->sv_stats->rpcbadfmt++;
1242         svc_putnl(resv, 1);     /* REJECT */
1243         svc_putnl(resv, 0);     /* RPC_MISMATCH */
1244         svc_putnl(resv, 2);     /* Only RPCv2 supported */
1245         svc_putnl(resv, 2);
1246         goto sendit;
1247 
1248 err_bad_auth:
1249         dprintk("svc: authentication failed (%d)\n", ntohl(auth_stat));
1250         serv->sv_stats->rpcbadauth++;
1251         /* Restore write pointer to location of accept status: */
1252         xdr_ressize_check(rqstp, reply_statp);
1253         svc_putnl(resv, 1);     /* REJECT */
1254         svc_putnl(resv, 1);     /* AUTH_ERROR */
1255         svc_putnl(resv, ntohl(auth_stat));      /* status */
1256         goto sendit;
1257 
1258 err_bad_prog:
1259         dprintk("svc: unknown program %d\n", prog);
1260         serv->sv_stats->rpcbadfmt++;
1261         svc_putnl(resv, RPC_PROG_UNAVAIL);
1262         goto sendit;
1263 
1264 err_bad_vers:
1265         svc_printk(rqstp, "unknown version (%d for prog %d, %s)\n",
1266                        vers, prog, progp->pg_name);
1267 
1268         serv->sv_stats->rpcbadfmt++;
1269         svc_putnl(resv, RPC_PROG_MISMATCH);
1270         svc_putnl(resv, progp->pg_lovers);
1271         svc_putnl(resv, progp->pg_hivers);
1272         goto sendit;
1273 
1274 err_bad_proc:
1275         svc_printk(rqstp, "unknown procedure (%d)\n", proc);
1276 
1277         serv->sv_stats->rpcbadfmt++;
1278         svc_putnl(resv, RPC_PROC_UNAVAIL);
1279         goto sendit;
1280 
1281 err_garbage:
1282         svc_printk(rqstp, "failed to decode args\n");
1283 
1284         rpc_stat = rpc_garbage_args;
1285 err_bad:
1286         serv->sv_stats->rpcbadfmt++;
1287         svc_putnl(resv, ntohl(rpc_stat));
1288         goto sendit;
1289 }
1290 
1291 /*
1292  * Process the RPC request.
1293  */
1294 int
1295 svc_process(struct svc_rqst *rqstp)
1296 {
1297         struct kvec             *argv = &rqstp->rq_arg.head[0];
1298         struct kvec             *resv = &rqstp->rq_res.head[0];
1299         struct svc_serv         *serv = rqstp->rq_server;
1300         u32                     dir;
1301 
1302         /*
1303          * Setup response xdr_buf.
1304          * Initially it has just one page
1305          */
1306         rqstp->rq_next_page = &rqstp->rq_respages[1];
1307         resv->iov_base = page_address(rqstp->rq_respages[0]);
1308         resv->iov_len = 0;
1309         rqstp->rq_res.pages = rqstp->rq_respages + 1;
1310         rqstp->rq_res.len = 0;
1311         rqstp->rq_res.page_base = 0;
1312         rqstp->rq_res.page_len = 0;
1313         rqstp->rq_res.buflen = PAGE_SIZE;
1314         rqstp->rq_res.tail[0].iov_base = NULL;
1315         rqstp->rq_res.tail[0].iov_len = 0;
1316 
1317         dir  = svc_getnl(argv);
1318         if (dir != 0) {
1319                 /* direction != CALL */
1320                 svc_printk(rqstp, "bad direction %d, dropping request\n", dir);
1321                 serv->sv_stats->rpcbadfmt++;
1322                 goto out_drop;
1323         }
1324 
1325         /* Returns 1 for send, 0 for drop */
1326         if (likely(svc_process_common(rqstp, argv, resv))) {
1327                 int ret = svc_send(rqstp);
1328 
1329                 trace_svc_process(rqstp, ret);
1330                 return ret;
1331         }
1332 out_drop:
1333         trace_svc_process(rqstp, 0);
1334         svc_drop(rqstp);
1335         return 0;
1336 }
1337 EXPORT_SYMBOL_GPL(svc_process);
1338 
1339 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1340 /*
1341  * Process a backchannel RPC request that arrived over an existing
1342  * outbound connection
1343  */
1344 int
1345 bc_svc_process(struct svc_serv *serv, struct rpc_rqst *req,
1346                struct svc_rqst *rqstp)
1347 {
1348         struct kvec     *argv = &rqstp->rq_arg.head[0];
1349         struct kvec     *resv = &rqstp->rq_res.head[0];
1350         struct rpc_task *task;
1351         int proc_error;
1352         int error;
1353 
1354         dprintk("svc: %s(%p)\n", __func__, req);
1355 
1356         /* Build the svc_rqst used by the common processing routine */
1357         rqstp->rq_xprt = serv->sv_bc_xprt;
1358         rqstp->rq_xid = req->rq_xid;
1359         rqstp->rq_prot = req->rq_xprt->prot;
1360         rqstp->rq_server = serv;
1361 
1362         rqstp->rq_addrlen = sizeof(req->rq_xprt->addr);
1363         memcpy(&rqstp->rq_addr, &req->rq_xprt->addr, rqstp->rq_addrlen);
1364         memcpy(&rqstp->rq_arg, &req->rq_rcv_buf, sizeof(rqstp->rq_arg));
1365         memcpy(&rqstp->rq_res, &req->rq_snd_buf, sizeof(rqstp->rq_res));
1366 
1367         /* Adjust the argument buffer length */
1368         rqstp->rq_arg.len = req->rq_private_buf.len;
1369         if (rqstp->rq_arg.len <= rqstp->rq_arg.head[0].iov_len) {
1370                 rqstp->rq_arg.head[0].iov_len = rqstp->rq_arg.len;
1371                 rqstp->rq_arg.page_len = 0;
1372         } else if (rqstp->rq_arg.len <= rqstp->rq_arg.head[0].iov_len +
1373                         rqstp->rq_arg.page_len)
1374                 rqstp->rq_arg.page_len = rqstp->rq_arg.len -
1375                         rqstp->rq_arg.head[0].iov_len;
1376         else
1377                 rqstp->rq_arg.len = rqstp->rq_arg.head[0].iov_len +
1378                         rqstp->rq_arg.page_len;
1379 
1380         /* reset result send buffer "put" position */
1381         resv->iov_len = 0;
1382 
1383         /*
1384          * Skip the next two words because they've already been
1385          * processed in the transport
1386          */
1387         svc_getu32(argv);       /* XID */
1388         svc_getnl(argv);        /* CALLDIR */
1389 
1390         /* Parse and execute the bc call */
1391         proc_error = svc_process_common(rqstp, argv, resv);
1392 
1393         atomic_inc(&req->rq_xprt->bc_free_slots);
1394         if (!proc_error) {
1395                 /* Processing error: drop the request */
1396                 xprt_free_bc_request(req);
1397                 return 0;
1398         }
1399 
1400         /* Finally, send the reply synchronously */
1401         memcpy(&req->rq_snd_buf, &rqstp->rq_res, sizeof(req->rq_snd_buf));
1402         task = rpc_run_bc_task(req);
1403         if (IS_ERR(task)) {
1404                 error = PTR_ERR(task);
1405                 goto out;
1406         }
1407 
1408         WARN_ON_ONCE(atomic_read(&task->tk_count) != 1);
1409         error = task->tk_status;
1410         rpc_put_task(task);
1411 
1412 out:
1413         dprintk("svc: %s(), error=%d\n", __func__, error);
1414         return error;
1415 }
1416 EXPORT_SYMBOL_GPL(bc_svc_process);
1417 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1418 
1419 /*
1420  * Return (transport-specific) limit on the rpc payload.
1421  */
1422 u32 svc_max_payload(const struct svc_rqst *rqstp)
1423 {
1424         u32 max = rqstp->rq_xprt->xpt_class->xcl_max_payload;
1425 
1426         if (rqstp->rq_server->sv_max_payload < max)
1427                 max = rqstp->rq_server->sv_max_payload;
1428         return max;
1429 }
1430 EXPORT_SYMBOL_GPL(svc_max_payload);
1431 

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