xref: /openbmc/linux/net/sunrpc/svc.c (revision 7adae489fe794e3e203ff168595f635d0b845e59)
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 
22 #include <linux/sunrpc/types.h>
23 #include <linux/sunrpc/xdr.h>
24 #include <linux/sunrpc/stats.h>
25 #include <linux/sunrpc/svcsock.h>
26 #include <linux/sunrpc/clnt.h>
27 
28 #define RPCDBG_FACILITY	RPCDBG_SVCDSP
29 #define RPC_PARANOIA 1
30 
31 /*
32  * Mode for mapping cpus to pools.
33  */
34 enum {
35 	SVC_POOL_NONE = -1,	/* uninitialised, choose one of the others */
36 	SVC_POOL_GLOBAL,	/* no mapping, just a single global pool
37 				 * (legacy & UP mode) */
38 	SVC_POOL_PERCPU,	/* one pool per cpu */
39 	SVC_POOL_PERNODE	/* one pool per numa node */
40 };
41 
42 /*
43  * Structure for mapping cpus to pools and vice versa.
44  * Setup once during sunrpc initialisation.
45  */
46 static struct svc_pool_map {
47 	int mode;			/* Note: int not enum to avoid
48 					 * warnings about "enumeration value
49 					 * not handled in switch" */
50 	unsigned int npools;
51 	unsigned int *pool_to;		/* maps pool id to cpu or node */
52 	unsigned int *to_pool;		/* maps cpu or node to pool id */
53 } svc_pool_map = {
54 	.mode = SVC_POOL_NONE
55 };
56 
57 
58 /*
59  * Detect best pool mapping mode heuristically,
60  * according to the machine's topology.
61  */
62 static int
63 svc_pool_map_choose_mode(void)
64 {
65 	unsigned int node;
66 
67 	if (num_online_nodes() > 1) {
68 		/*
69 		 * Actually have multiple NUMA nodes,
70 		 * so split pools on NUMA node boundaries
71 		 */
72 		return SVC_POOL_PERNODE;
73 	}
74 
75 	node = any_online_node(node_online_map);
76 	if (nr_cpus_node(node) > 2) {
77 		/*
78 		 * Non-trivial SMP, or CONFIG_NUMA on
79 		 * non-NUMA hardware, e.g. with a generic
80 		 * x86_64 kernel on Xeons.  In this case we
81 		 * want to divide the pools on cpu boundaries.
82 		 */
83 		return SVC_POOL_PERCPU;
84 	}
85 
86 	/* default: one global pool */
87 	return SVC_POOL_GLOBAL;
88 }
89 
90 /*
91  * Allocate the to_pool[] and pool_to[] arrays.
92  * Returns 0 on success or an errno.
93  */
94 static int
95 svc_pool_map_alloc_arrays(struct svc_pool_map *m, unsigned int maxpools)
96 {
97 	m->to_pool = kcalloc(maxpools, sizeof(unsigned int), GFP_KERNEL);
98 	if (!m->to_pool)
99 		goto fail;
100 	m->pool_to = kcalloc(maxpools, sizeof(unsigned int), GFP_KERNEL);
101 	if (!m->pool_to)
102 		goto fail_free;
103 
104 	return 0;
105 
106 fail_free:
107 	kfree(m->to_pool);
108 fail:
109 	return -ENOMEM;
110 }
111 
112 /*
113  * Initialise the pool map for SVC_POOL_PERCPU mode.
114  * Returns number of pools or <0 on error.
115  */
116 static int
117 svc_pool_map_init_percpu(struct svc_pool_map *m)
118 {
119 	unsigned int maxpools = highest_possible_processor_id()+1;
120 	unsigned int pidx = 0;
121 	unsigned int cpu;
122 	int err;
123 
124 	err = svc_pool_map_alloc_arrays(m, maxpools);
125 	if (err)
126 		return err;
127 
128 	for_each_online_cpu(cpu) {
129 		BUG_ON(pidx > maxpools);
130 		m->to_pool[cpu] = pidx;
131 		m->pool_to[pidx] = cpu;
132 		pidx++;
133 	}
134 	/* cpus brought online later all get mapped to pool0, sorry */
135 
136 	return pidx;
137 };
138 
139 
140 /*
141  * Initialise the pool map for SVC_POOL_PERNODE mode.
142  * Returns number of pools or <0 on error.
143  */
144 static int
145 svc_pool_map_init_pernode(struct svc_pool_map *m)
146 {
147 	unsigned int maxpools = highest_possible_node_id()+1;
148 	unsigned int pidx = 0;
149 	unsigned int node;
150 	int err;
151 
152 	err = svc_pool_map_alloc_arrays(m, maxpools);
153 	if (err)
154 		return err;
155 
156 	for_each_node_with_cpus(node) {
157 		/* some architectures (e.g. SN2) have cpuless nodes */
158 		BUG_ON(pidx > maxpools);
159 		m->to_pool[node] = pidx;
160 		m->pool_to[pidx] = node;
161 		pidx++;
162 	}
163 	/* nodes brought online later all get mapped to pool0, sorry */
164 
165 	return pidx;
166 }
167 
168 
169 /*
170  * Build the global map of cpus to pools and vice versa.
171  */
172 static unsigned int
173 svc_pool_map_init(void)
174 {
175 	struct svc_pool_map *m = &svc_pool_map;
176 	int npools = -1;
177 
178 	if (m->mode != SVC_POOL_NONE)
179 		return m->npools;
180 
181 	m->mode = svc_pool_map_choose_mode();
182 
183 	switch (m->mode) {
184 	case SVC_POOL_PERCPU:
185 		npools = svc_pool_map_init_percpu(m);
186 		break;
187 	case SVC_POOL_PERNODE:
188 		npools = svc_pool_map_init_pernode(m);
189 		break;
190 	}
191 
192 	if (npools < 0) {
193 		/* default, or memory allocation failure */
194 		npools = 1;
195 		m->mode = SVC_POOL_GLOBAL;
196 	}
197 	m->npools = npools;
198 
199 	return m->npools;
200 }
201 
202 /*
203  * Set the current thread's cpus_allowed mask so that it
204  * will only run on cpus in the given pool.
205  *
206  * Returns 1 and fills in oldmask iff a cpumask was applied.
207  */
208 static inline int
209 svc_pool_map_set_cpumask(unsigned int pidx, cpumask_t *oldmask)
210 {
211 	struct svc_pool_map *m = &svc_pool_map;
212 	unsigned int node; /* or cpu */
213 
214 	/*
215 	 * The caller checks for sv_nrpools > 1, which
216 	 * implies that we've been initialized and the
217 	 * map mode is not NONE.
218 	 */
219 	BUG_ON(m->mode == SVC_POOL_NONE);
220 
221 	switch (m->mode)
222 	{
223 	default:
224 		return 0;
225 	case SVC_POOL_PERCPU:
226 		node = m->pool_to[pidx];
227 		*oldmask = current->cpus_allowed;
228 		set_cpus_allowed(current, cpumask_of_cpu(node));
229 		return 1;
230 	case SVC_POOL_PERNODE:
231 		node = m->pool_to[pidx];
232 		*oldmask = current->cpus_allowed;
233 		set_cpus_allowed(current, node_to_cpumask(node));
234 		return 1;
235 	}
236 }
237 
238 /*
239  * Use the mapping mode to choose a pool for a given CPU.
240  * Used when enqueueing an incoming RPC.  Always returns
241  * a non-NULL pool pointer.
242  */
243 struct svc_pool *
244 svc_pool_for_cpu(struct svc_serv *serv, int cpu)
245 {
246 	struct svc_pool_map *m = &svc_pool_map;
247 	unsigned int pidx = 0;
248 
249 	/*
250 	 * SVC_POOL_NONE happens in a pure client when
251 	 * lockd is brought up, so silently treat it the
252 	 * same as SVC_POOL_GLOBAL.
253 	 */
254 
255 	switch (m->mode) {
256 	case SVC_POOL_PERCPU:
257 		pidx = m->to_pool[cpu];
258 		break;
259 	case SVC_POOL_PERNODE:
260 		pidx = m->to_pool[cpu_to_node(cpu)];
261 		break;
262 	}
263 	return &serv->sv_pools[pidx % serv->sv_nrpools];
264 }
265 
266 
267 /*
268  * Create an RPC service
269  */
270 static struct svc_serv *
271 __svc_create(struct svc_program *prog, unsigned int bufsize, int npools,
272 	   void (*shutdown)(struct svc_serv *serv))
273 {
274 	struct svc_serv	*serv;
275 	int vers;
276 	unsigned int xdrsize;
277 	unsigned int i;
278 
279 	if (!(serv = kzalloc(sizeof(*serv), GFP_KERNEL)))
280 		return NULL;
281 	serv->sv_name      = prog->pg_name;
282 	serv->sv_program   = prog;
283 	serv->sv_nrthreads = 1;
284 	serv->sv_stats     = prog->pg_stats;
285 	serv->sv_bufsz	   = bufsize? bufsize : 4096;
286 	serv->sv_shutdown  = shutdown;
287 	xdrsize = 0;
288 	while (prog) {
289 		prog->pg_lovers = prog->pg_nvers-1;
290 		for (vers=0; vers<prog->pg_nvers ; vers++)
291 			if (prog->pg_vers[vers]) {
292 				prog->pg_hivers = vers;
293 				if (prog->pg_lovers > vers)
294 					prog->pg_lovers = vers;
295 				if (prog->pg_vers[vers]->vs_xdrsize > xdrsize)
296 					xdrsize = prog->pg_vers[vers]->vs_xdrsize;
297 			}
298 		prog = prog->pg_next;
299 	}
300 	serv->sv_xdrsize   = xdrsize;
301 	INIT_LIST_HEAD(&serv->sv_tempsocks);
302 	INIT_LIST_HEAD(&serv->sv_permsocks);
303 	init_timer(&serv->sv_temptimer);
304 	spin_lock_init(&serv->sv_lock);
305 
306 	serv->sv_nrpools = npools;
307 	serv->sv_pools =
308 		kcalloc(sizeof(struct svc_pool), serv->sv_nrpools,
309 			GFP_KERNEL);
310 	if (!serv->sv_pools) {
311 		kfree(serv);
312 		return NULL;
313 	}
314 
315 	for (i = 0; i < serv->sv_nrpools; i++) {
316 		struct svc_pool *pool = &serv->sv_pools[i];
317 
318 		dprintk("initialising pool %u for %s\n",
319 				i, serv->sv_name);
320 
321 		pool->sp_id = i;
322 		INIT_LIST_HEAD(&pool->sp_threads);
323 		INIT_LIST_HEAD(&pool->sp_sockets);
324 		INIT_LIST_HEAD(&pool->sp_all_threads);
325 		spin_lock_init(&pool->sp_lock);
326 	}
327 
328 
329 	/* Remove any stale portmap registrations */
330 	svc_register(serv, 0, 0);
331 
332 	return serv;
333 }
334 
335 struct svc_serv *
336 svc_create(struct svc_program *prog, unsigned int bufsize,
337 		void (*shutdown)(struct svc_serv *serv))
338 {
339 	return __svc_create(prog, bufsize, /*npools*/1, shutdown);
340 }
341 
342 struct svc_serv *
343 svc_create_pooled(struct svc_program *prog, unsigned int bufsize,
344 		void (*shutdown)(struct svc_serv *serv),
345 		  svc_thread_fn func, int sig, struct module *mod)
346 {
347 	struct svc_serv *serv;
348 	unsigned int npools = svc_pool_map_init();
349 
350 	serv = __svc_create(prog, bufsize, npools, shutdown);
351 
352 	if (serv != NULL) {
353 		serv->sv_function = func;
354 		serv->sv_kill_signal = sig;
355 		serv->sv_module = mod;
356 	}
357 
358 	return serv;
359 }
360 
361 /*
362  * Destroy an RPC service.  Should be called with the BKL held
363  */
364 void
365 svc_destroy(struct svc_serv *serv)
366 {
367 	struct svc_sock	*svsk;
368 
369 	dprintk("RPC: svc_destroy(%s, %d)\n",
370 				serv->sv_program->pg_name,
371 				serv->sv_nrthreads);
372 
373 	if (serv->sv_nrthreads) {
374 		if (--(serv->sv_nrthreads) != 0) {
375 			svc_sock_update_bufs(serv);
376 			return;
377 		}
378 	} else
379 		printk("svc_destroy: no threads for serv=%p!\n", serv);
380 
381 	del_timer_sync(&serv->sv_temptimer);
382 
383 	while (!list_empty(&serv->sv_tempsocks)) {
384 		svsk = list_entry(serv->sv_tempsocks.next,
385 				  struct svc_sock,
386 				  sk_list);
387 		svc_delete_socket(svsk);
388 	}
389 	if (serv->sv_shutdown)
390 		serv->sv_shutdown(serv);
391 
392 	while (!list_empty(&serv->sv_permsocks)) {
393 		svsk = list_entry(serv->sv_permsocks.next,
394 				  struct svc_sock,
395 				  sk_list);
396 		svc_delete_socket(svsk);
397 	}
398 
399 	cache_clean_deferred(serv);
400 
401 	/* Unregister service with the portmapper */
402 	svc_register(serv, 0, 0);
403 	kfree(serv->sv_pools);
404 	kfree(serv);
405 }
406 
407 /*
408  * Allocate an RPC server's buffer space.
409  * We allocate pages and place them in rq_argpages.
410  */
411 static int
412 svc_init_buffer(struct svc_rqst *rqstp, unsigned int size)
413 {
414 	int pages;
415 	int arghi;
416 
417 	if (size > RPCSVC_MAXPAYLOAD)
418 		size = RPCSVC_MAXPAYLOAD;
419 	pages = 2 + (size+ PAGE_SIZE -1) / PAGE_SIZE;
420 	arghi = 0;
421 	BUG_ON(pages > RPCSVC_MAXPAGES);
422 	while (pages) {
423 		struct page *p = alloc_page(GFP_KERNEL);
424 		if (!p)
425 			break;
426 		rqstp->rq_pages[arghi++] = p;
427 		pages--;
428 	}
429 	return ! pages;
430 }
431 
432 /*
433  * Release an RPC server buffer
434  */
435 static void
436 svc_release_buffer(struct svc_rqst *rqstp)
437 {
438 	int i;
439 	for (i=0; i<ARRAY_SIZE(rqstp->rq_pages); i++)
440 		if (rqstp->rq_pages[i])
441 			put_page(rqstp->rq_pages[i]);
442 }
443 
444 /*
445  * Create a thread in the given pool.  Caller must hold BKL.
446  * On a NUMA or SMP machine, with a multi-pool serv, the thread
447  * will be restricted to run on the cpus belonging to the pool.
448  */
449 static int
450 __svc_create_thread(svc_thread_fn func, struct svc_serv *serv,
451 		    struct svc_pool *pool)
452 {
453 	struct svc_rqst	*rqstp;
454 	int		error = -ENOMEM;
455 	int		have_oldmask = 0;
456 	cpumask_t	oldmask;
457 
458 	rqstp = kzalloc(sizeof(*rqstp), GFP_KERNEL);
459 	if (!rqstp)
460 		goto out;
461 
462 	init_waitqueue_head(&rqstp->rq_wait);
463 
464 	if (!(rqstp->rq_argp = kmalloc(serv->sv_xdrsize, GFP_KERNEL))
465 	 || !(rqstp->rq_resp = kmalloc(serv->sv_xdrsize, GFP_KERNEL))
466 	 || !svc_init_buffer(rqstp, serv->sv_bufsz))
467 		goto out_thread;
468 
469 	serv->sv_nrthreads++;
470 	spin_lock_bh(&pool->sp_lock);
471 	pool->sp_nrthreads++;
472 	list_add(&rqstp->rq_all, &pool->sp_all_threads);
473 	spin_unlock_bh(&pool->sp_lock);
474 	rqstp->rq_server = serv;
475 	rqstp->rq_pool = pool;
476 
477 	if (serv->sv_nrpools > 1)
478 		have_oldmask = svc_pool_map_set_cpumask(pool->sp_id, &oldmask);
479 
480 	error = kernel_thread((int (*)(void *)) func, rqstp, 0);
481 
482 	if (have_oldmask)
483 		set_cpus_allowed(current, oldmask);
484 
485 	if (error < 0)
486 		goto out_thread;
487 	svc_sock_update_bufs(serv);
488 	error = 0;
489 out:
490 	return error;
491 
492 out_thread:
493 	svc_exit_thread(rqstp);
494 	goto out;
495 }
496 
497 /*
498  * Create a thread in the default pool.  Caller must hold BKL.
499  */
500 int
501 svc_create_thread(svc_thread_fn func, struct svc_serv *serv)
502 {
503 	return __svc_create_thread(func, serv, &serv->sv_pools[0]);
504 }
505 
506 /*
507  * Choose a pool in which to create a new thread, for svc_set_num_threads
508  */
509 static inline struct svc_pool *
510 choose_pool(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
511 {
512 	if (pool != NULL)
513 		return pool;
514 
515  	return &serv->sv_pools[(*state)++ % serv->sv_nrpools];
516 }
517 
518 /*
519  * Choose a thread to kill, for svc_set_num_threads
520  */
521 static inline struct task_struct *
522 choose_victim(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
523 {
524 	unsigned int i;
525 	struct task_struct *task = NULL;
526 
527 	if (pool != NULL) {
528 		spin_lock_bh(&pool->sp_lock);
529 	} else {
530 		/* choose a pool in round-robin fashion */
531  		for (i = 0; i < serv->sv_nrpools; i++) {
532  			pool = &serv->sv_pools[--(*state) % serv->sv_nrpools];
533 			spin_lock_bh(&pool->sp_lock);
534  			if (!list_empty(&pool->sp_all_threads))
535  				goto found_pool;
536 			spin_unlock_bh(&pool->sp_lock);
537  		}
538 		return NULL;
539 	}
540 
541 found_pool:
542 	if (!list_empty(&pool->sp_all_threads)) {
543 		struct svc_rqst *rqstp;
544 
545 		/*
546 		 * Remove from the pool->sp_all_threads list
547 		 * so we don't try to kill it again.
548 		 */
549 		rqstp = list_entry(pool->sp_all_threads.next, struct svc_rqst, rq_all);
550 		list_del_init(&rqstp->rq_all);
551 		task = rqstp->rq_task;
552     	}
553 	spin_unlock_bh(&pool->sp_lock);
554 
555 	return task;
556 }
557 
558 /*
559  * Create or destroy enough new threads to make the number
560  * of threads the given number.  If `pool' is non-NULL, applies
561  * only to threads in that pool, otherwise round-robins between
562  * all pools.  Must be called with a svc_get() reference and
563  * the BKL held.
564  *
565  * Destroying threads relies on the service threads filling in
566  * rqstp->rq_task, which only the nfs ones do.  Assumes the serv
567  * has been created using svc_create_pooled().
568  *
569  * Based on code that used to be in nfsd_svc() but tweaked
570  * to be pool-aware.
571  */
572 int
573 svc_set_num_threads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
574 {
575 	struct task_struct *victim;
576 	int error = 0;
577 	unsigned int state = serv->sv_nrthreads-1;
578 
579 	if (pool == NULL) {
580 		/* The -1 assumes caller has done a svc_get() */
581 		nrservs -= (serv->sv_nrthreads-1);
582 	} else {
583 		spin_lock_bh(&pool->sp_lock);
584 		nrservs -= pool->sp_nrthreads;
585 		spin_unlock_bh(&pool->sp_lock);
586 	}
587 
588 	/* create new threads */
589 	while (nrservs > 0) {
590 		nrservs--;
591 		__module_get(serv->sv_module);
592 		error = __svc_create_thread(serv->sv_function, serv,
593 					    choose_pool(serv, pool, &state));
594 		if (error < 0) {
595 			module_put(serv->sv_module);
596 			break;
597 		}
598 	}
599 	/* destroy old threads */
600 	while (nrservs < 0 &&
601 	       (victim = choose_victim(serv, pool, &state)) != NULL) {
602 		send_sig(serv->sv_kill_signal, victim, 1);
603 		nrservs++;
604 	}
605 
606 	return error;
607 }
608 
609 /*
610  * Called from a server thread as it's exiting.  Caller must hold BKL.
611  */
612 void
613 svc_exit_thread(struct svc_rqst *rqstp)
614 {
615 	struct svc_serv	*serv = rqstp->rq_server;
616 	struct svc_pool	*pool = rqstp->rq_pool;
617 
618 	svc_release_buffer(rqstp);
619 	kfree(rqstp->rq_resp);
620 	kfree(rqstp->rq_argp);
621 	kfree(rqstp->rq_auth_data);
622 
623 	spin_lock_bh(&pool->sp_lock);
624 	pool->sp_nrthreads--;
625 	list_del(&rqstp->rq_all);
626 	spin_unlock_bh(&pool->sp_lock);
627 
628 	kfree(rqstp);
629 
630 	/* Release the server */
631 	if (serv)
632 		svc_destroy(serv);
633 }
634 
635 /*
636  * Register an RPC service with the local portmapper.
637  * To unregister a service, call this routine with
638  * proto and port == 0.
639  */
640 int
641 svc_register(struct svc_serv *serv, int proto, unsigned short port)
642 {
643 	struct svc_program	*progp;
644 	unsigned long		flags;
645 	int			i, error = 0, dummy;
646 
647 	progp = serv->sv_program;
648 
649 	dprintk("RPC: svc_register(%s, %s, %d)\n",
650 		progp->pg_name, proto == IPPROTO_UDP? "udp" : "tcp", port);
651 
652 	if (!port)
653 		clear_thread_flag(TIF_SIGPENDING);
654 
655 	for (i = 0; i < progp->pg_nvers; i++) {
656 		if (progp->pg_vers[i] == NULL)
657 			continue;
658 		error = rpc_register(progp->pg_prog, i, proto, port, &dummy);
659 		if (error < 0)
660 			break;
661 		if (port && !dummy) {
662 			error = -EACCES;
663 			break;
664 		}
665 	}
666 
667 	if (!port) {
668 		spin_lock_irqsave(&current->sighand->siglock, flags);
669 		recalc_sigpending();
670 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
671 	}
672 
673 	return error;
674 }
675 
676 /*
677  * Process the RPC request.
678  */
679 int
680 svc_process(struct svc_rqst *rqstp)
681 {
682 	struct svc_program	*progp;
683 	struct svc_version	*versp = NULL;	/* compiler food */
684 	struct svc_procedure	*procp = NULL;
685 	struct kvec *		argv = &rqstp->rq_arg.head[0];
686 	struct kvec *		resv = &rqstp->rq_res.head[0];
687 	struct svc_serv		*serv = rqstp->rq_server;
688 	kxdrproc_t		xdr;
689 	__be32			*statp;
690 	u32			dir, prog, vers, proc;
691 	__be32			auth_stat, rpc_stat;
692 	int			auth_res;
693 	__be32			*accept_statp;
694 
695 	rpc_stat = rpc_success;
696 
697 	if (argv->iov_len < 6*4)
698 		goto err_short_len;
699 
700 	/* setup response xdr_buf.
701 	 * Initially it has just one page
702 	 */
703 	rqstp->rq_resused = 1;
704 	resv->iov_base = page_address(rqstp->rq_respages[0]);
705 	resv->iov_len = 0;
706 	rqstp->rq_res.pages = rqstp->rq_respages + 1;
707 	rqstp->rq_res.len = 0;
708 	rqstp->rq_res.page_base = 0;
709 	rqstp->rq_res.page_len = 0;
710 	rqstp->rq_res.buflen = PAGE_SIZE;
711 	rqstp->rq_res.tail[0].iov_base = NULL;
712 	rqstp->rq_res.tail[0].iov_len = 0;
713 	/* Will be turned off only in gss privacy case: */
714 	rqstp->rq_sendfile_ok = 1;
715 	/* tcp needs a space for the record length... */
716 	if (rqstp->rq_prot == IPPROTO_TCP)
717 		svc_putnl(resv, 0);
718 
719 	rqstp->rq_xid = svc_getu32(argv);
720 	svc_putu32(resv, rqstp->rq_xid);
721 
722 	dir  = svc_getnl(argv);
723 	vers = svc_getnl(argv);
724 
725 	/* First words of reply: */
726 	svc_putnl(resv, 1);		/* REPLY */
727 
728 	if (dir != 0)		/* direction != CALL */
729 		goto err_bad_dir;
730 	if (vers != 2)		/* RPC version number */
731 		goto err_bad_rpc;
732 
733 	/* Save position in case we later decide to reject: */
734 	accept_statp = resv->iov_base + resv->iov_len;
735 
736 	svc_putnl(resv, 0);		/* ACCEPT */
737 
738 	rqstp->rq_prog = prog = svc_getnl(argv);	/* program number */
739 	rqstp->rq_vers = vers = svc_getnl(argv);	/* version number */
740 	rqstp->rq_proc = proc = svc_getnl(argv);	/* procedure number */
741 
742 	progp = serv->sv_program;
743 
744 	for (progp = serv->sv_program; progp; progp = progp->pg_next)
745 		if (prog == progp->pg_prog)
746 			break;
747 
748 	/*
749 	 * Decode auth data, and add verifier to reply buffer.
750 	 * We do this before anything else in order to get a decent
751 	 * auth verifier.
752 	 */
753 	auth_res = svc_authenticate(rqstp, &auth_stat);
754 	/* Also give the program a chance to reject this call: */
755 	if (auth_res == SVC_OK && progp) {
756 		auth_stat = rpc_autherr_badcred;
757 		auth_res = progp->pg_authenticate(rqstp);
758 	}
759 	switch (auth_res) {
760 	case SVC_OK:
761 		break;
762 	case SVC_GARBAGE:
763 		rpc_stat = rpc_garbage_args;
764 		goto err_bad;
765 	case SVC_SYSERR:
766 		rpc_stat = rpc_system_err;
767 		goto err_bad;
768 	case SVC_DENIED:
769 		goto err_bad_auth;
770 	case SVC_DROP:
771 		goto dropit;
772 	case SVC_COMPLETE:
773 		goto sendit;
774 	}
775 
776 	if (progp == NULL)
777 		goto err_bad_prog;
778 
779 	if (vers >= progp->pg_nvers ||
780 	  !(versp = progp->pg_vers[vers]))
781 		goto err_bad_vers;
782 
783 	procp = versp->vs_proc + proc;
784 	if (proc >= versp->vs_nproc || !procp->pc_func)
785 		goto err_bad_proc;
786 	rqstp->rq_server   = serv;
787 	rqstp->rq_procinfo = procp;
788 
789 	/* Syntactic check complete */
790 	serv->sv_stats->rpccnt++;
791 
792 	/* Build the reply header. */
793 	statp = resv->iov_base +resv->iov_len;
794 	svc_putnl(resv, RPC_SUCCESS);
795 
796 	/* Bump per-procedure stats counter */
797 	procp->pc_count++;
798 
799 	/* Initialize storage for argp and resp */
800 	memset(rqstp->rq_argp, 0, procp->pc_argsize);
801 	memset(rqstp->rq_resp, 0, procp->pc_ressize);
802 
803 	/* un-reserve some of the out-queue now that we have a
804 	 * better idea of reply size
805 	 */
806 	if (procp->pc_xdrressize)
807 		svc_reserve(rqstp, procp->pc_xdrressize<<2);
808 
809 	/* Call the function that processes the request. */
810 	if (!versp->vs_dispatch) {
811 		/* Decode arguments */
812 		xdr = procp->pc_decode;
813 		if (xdr && !xdr(rqstp, argv->iov_base, rqstp->rq_argp))
814 			goto err_garbage;
815 
816 		*statp = procp->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
817 
818 		/* Encode reply */
819 		if (*statp == rpc_success && (xdr = procp->pc_encode)
820 		 && !xdr(rqstp, resv->iov_base+resv->iov_len, rqstp->rq_resp)) {
821 			dprintk("svc: failed to encode reply\n");
822 			/* serv->sv_stats->rpcsystemerr++; */
823 			*statp = rpc_system_err;
824 		}
825 	} else {
826 		dprintk("svc: calling dispatcher\n");
827 		if (!versp->vs_dispatch(rqstp, statp)) {
828 			/* Release reply info */
829 			if (procp->pc_release)
830 				procp->pc_release(rqstp, NULL, rqstp->rq_resp);
831 			goto dropit;
832 		}
833 	}
834 
835 	/* Check RPC status result */
836 	if (*statp != rpc_success)
837 		resv->iov_len = ((void*)statp)  - resv->iov_base + 4;
838 
839 	/* Release reply info */
840 	if (procp->pc_release)
841 		procp->pc_release(rqstp, NULL, rqstp->rq_resp);
842 
843 	if (procp->pc_encode == NULL)
844 		goto dropit;
845 
846  sendit:
847 	if (svc_authorise(rqstp))
848 		goto dropit;
849 	return svc_send(rqstp);
850 
851  dropit:
852 	svc_authorise(rqstp);	/* doesn't hurt to call this twice */
853 	dprintk("svc: svc_process dropit\n");
854 	svc_drop(rqstp);
855 	return 0;
856 
857 err_short_len:
858 #ifdef RPC_PARANOIA
859 	printk("svc: short len %Zd, dropping request\n", argv->iov_len);
860 #endif
861 	goto dropit;			/* drop request */
862 
863 err_bad_dir:
864 #ifdef RPC_PARANOIA
865 	printk("svc: bad direction %d, dropping request\n", dir);
866 #endif
867 	serv->sv_stats->rpcbadfmt++;
868 	goto dropit;			/* drop request */
869 
870 err_bad_rpc:
871 	serv->sv_stats->rpcbadfmt++;
872 	svc_putnl(resv, 1);	/* REJECT */
873 	svc_putnl(resv, 0);	/* RPC_MISMATCH */
874 	svc_putnl(resv, 2);	/* Only RPCv2 supported */
875 	svc_putnl(resv, 2);
876 	goto sendit;
877 
878 err_bad_auth:
879 	dprintk("svc: authentication failed (%d)\n", ntohl(auth_stat));
880 	serv->sv_stats->rpcbadauth++;
881 	/* Restore write pointer to location of accept status: */
882 	xdr_ressize_check(rqstp, accept_statp);
883 	svc_putnl(resv, 1);	/* REJECT */
884 	svc_putnl(resv, 1);	/* AUTH_ERROR */
885 	svc_putnl(resv, ntohl(auth_stat));	/* status */
886 	goto sendit;
887 
888 err_bad_prog:
889 	dprintk("svc: unknown program %d\n", prog);
890 	serv->sv_stats->rpcbadfmt++;
891 	svc_putnl(resv, RPC_PROG_UNAVAIL);
892 	goto sendit;
893 
894 err_bad_vers:
895 #ifdef RPC_PARANOIA
896 	printk("svc: unknown version (%d)\n", vers);
897 #endif
898 	serv->sv_stats->rpcbadfmt++;
899 	svc_putnl(resv, RPC_PROG_MISMATCH);
900 	svc_putnl(resv, progp->pg_lovers);
901 	svc_putnl(resv, progp->pg_hivers);
902 	goto sendit;
903 
904 err_bad_proc:
905 #ifdef RPC_PARANOIA
906 	printk("svc: unknown procedure (%d)\n", proc);
907 #endif
908 	serv->sv_stats->rpcbadfmt++;
909 	svc_putnl(resv, RPC_PROC_UNAVAIL);
910 	goto sendit;
911 
912 err_garbage:
913 #ifdef RPC_PARANOIA
914 	printk("svc: failed to decode args\n");
915 #endif
916 	rpc_stat = rpc_garbage_args;
917 err_bad:
918 	serv->sv_stats->rpcbadfmt++;
919 	svc_putnl(resv, ntohl(rpc_stat));
920 	goto sendit;
921 }
922 
923 /*
924  * Return (transport-specific) limit on the rpc payload.
925  */
926 u32 svc_max_payload(const struct svc_rqst *rqstp)
927 {
928 	int max = RPCSVC_MAXPAYLOAD_TCP;
929 
930 	if (rqstp->rq_sock->sk_sock->type == SOCK_DGRAM)
931 		max = RPCSVC_MAXPAYLOAD_UDP;
932 	if (rqstp->rq_server->sv_bufsz < max)
933 		max = rqstp->rq_server->sv_bufsz;
934 	return max;
935 }
936 EXPORT_SYMBOL_GPL(svc_max_payload);
937