summaryrefslogtreecommitdiffstats
path: root/net/sunrpc/svc.c
blob: f3001f3626f631fca51ef9d911f3f521814162f3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
/*
 * linux/net/sunrpc/svc.c
 *
 * High-level RPC service routines
 *
 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
 *
 * Multiple threads pools and NUMAisation
 * Copyright (c) 2006 Silicon Graphics, Inc.
 * by Greg Banks <gnb@melbourne.sgi.com>
 */

#include <linux/linkage.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/net.h>
#include <linux/in.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/module.h>

#include <linux/sunrpc/types.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/stats.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/sunrpc/clnt.h>

#define RPCDBG_FACILITY	RPCDBG_SVCDSP
#define RPC_PARANOIA 1

/*
 * Mode for mapping cpus to pools.
 */
enum {
	SVC_POOL_NONE = -1,	/* uninitialised, choose one of the others */
	SVC_POOL_GLOBAL,	/* no mapping, just a single global pool
				 * (legacy & UP mode) */
	SVC_POOL_PERCPU,	/* one pool per cpu */
	SVC_POOL_PERNODE	/* one pool per numa node */
};

/*
 * Structure for mapping cpus to pools and vice versa.
 * Setup once during sunrpc initialisation.
 */
static struct svc_pool_map {
	int mode;			/* Note: int not enum to avoid
					 * warnings about "enumeration value
					 * not handled in switch" */
	unsigned int npools;
	unsigned int *pool_to;		/* maps pool id to cpu or node */
	unsigned int *to_pool;		/* maps cpu or node to pool id */
} svc_pool_map = {
	.mode = SVC_POOL_NONE
};


/*
 * Detect best pool mapping mode heuristically,
 * according to the machine's topology.
 */
static int
svc_pool_map_choose_mode(void)
{
	unsigned int node;

	if (num_online_nodes() > 1) {
		/*
		 * Actually have multiple NUMA nodes,
		 * so split pools on NUMA node boundaries
		 */
		return SVC_POOL_PERNODE;
	}

	node = any_online_node(node_online_map);
	if (nr_cpus_node(node) > 2) {
		/*
		 * Non-trivial SMP, or CONFIG_NUMA on
		 * non-NUMA hardware, e.g. with a generic
		 * x86_64 kernel on Xeons.  In this case we
		 * want to divide the pools on cpu boundaries.
		 */
		return SVC_POOL_PERCPU;
	}

	/* default: one global pool */
	return SVC_POOL_GLOBAL;
}

/*
 * Allocate the to_pool[] and pool_to[] arrays.
 * Returns 0 on success or an errno.
 */
static int
svc_pool_map_alloc_arrays(struct svc_pool_map *m, unsigned int maxpools)
{
	m->to_pool = kcalloc(maxpools, sizeof(unsigned int), GFP_KERNEL);
	if (!m->to_pool)
		goto fail;
	m->pool_to = kcalloc(maxpools, sizeof(unsigned int), GFP_KERNEL);
	if (!m->pool_to)
		goto fail_free;

	return 0;

fail_free:
	kfree(m->to_pool);
fail:
	return -ENOMEM;
}

/*
 * Initialise the pool map for SVC_POOL_PERCPU mode.
 * Returns number of pools or <0 on error.
 */
static int
svc_pool_map_init_percpu(struct svc_pool_map *m)
{
	unsigned int maxpools = highest_possible_processor_id()+1;
	unsigned int pidx = 0;
	unsigned int cpu;
	int err;

	err = svc_pool_map_alloc_arrays(m, maxpools);
	if (err)
		return err;

	for_each_online_cpu(cpu) {
		BUG_ON(pidx > maxpools);
		m->to_pool[cpu] = pidx;
		m->pool_to[pidx] = cpu;
		pidx++;
	}
	/* cpus brought online later all get mapped to pool0, sorry */

	return pidx;
};


/*
 * Initialise the pool map for SVC_POOL_PERNODE mode.
 * Returns number of pools or <0 on error.
 */
static int
svc_pool_map_init_pernode(struct svc_pool_map *m)
{
	unsigned int maxpools = highest_possible_node_id()+1;
	unsigned int pidx = 0;
	unsigned int node;
	int err;

	err = svc_pool_map_alloc_arrays(m, maxpools);
	if (err)
		return err;

	for_each_node_with_cpus(node) {
		/* some architectures (e.g. SN2) have cpuless nodes */
		BUG_ON(pidx > maxpools);
		m->to_pool[node] = pidx;
		m->pool_to[pidx] = node;
		pidx++;
	}
	/* nodes brought online later all get mapped to pool0, sorry */

	return pidx;
}


/*
 * Build the global map of cpus to pools and vice versa.
 */
static unsigned int
svc_pool_map_init(void)
{
	struct svc_pool_map *m = &svc_pool_map;
	int npools = -1;

	if (m->mode != SVC_POOL_NONE)
		return m->npools;

	m->mode = svc_pool_map_choose_mode();

	switch (m->mode) {
	case SVC_POOL_PERCPU:
		npools = svc_pool_map_init_percpu(m);
		break;
	case SVC_POOL_PERNODE:
		npools = svc_pool_map_init_pernode(m);
		break;
	}

	if (npools < 0) {
		/* default, or memory allocation failure */
		npools = 1;
		m->mode = SVC_POOL_GLOBAL;
	}
	m->npools = npools;

	return m->npools;
}

/*
 * Set the current thread's cpus_allowed mask so that it
 * will only run on cpus in the given pool.
 *
 * Returns 1 and fills in oldmask iff a cpumask was applied.
 */
static inline int
svc_pool_map_set_cpumask(unsigned int pidx, cpumask_t *oldmask)
{
	struct svc_pool_map *m = &svc_pool_map;
	unsigned int node; /* or cpu */

	/*
	 * The caller checks for sv_nrpools > 1, which
	 * implies that we've been initialized and the
	 * map mode is not NONE.
	 */
	BUG_ON(m->mode == SVC_POOL_NONE);

	switch (m->mode)
	{
	default:
		return 0;
	case SVC_POOL_PERCPU:
		node = m->pool_to[pidx];
		*oldmask = current->cpus_allowed;
		set_cpus_allowed(current, cpumask_of_cpu(node));
		return 1;
	case SVC_POOL_PERNODE:
		node = m->pool_to[pidx];
		*oldmask = current->cpus_allowed;
		set_cpus_allowed(current, node_to_cpumask(node));
		return 1;
	}
}

/*
 * Use the mapping mode to choose a pool for a given CPU.
 * Used when enqueueing an incoming RPC.  Always returns
 * a non-NULL pool pointer.
 */
struct svc_pool *
svc_pool_for_cpu(struct svc_serv *serv, int cpu)
{
	struct svc_pool_map *m = &svc_pool_map;
	unsigned int pidx = 0;

	/*
	 * SVC_POOL_NONE happens in a pure client when
	 * lockd is brought up, so silently treat it the
	 * same as SVC_POOL_GLOBAL.
	 */

	switch (m->mode) {
	case SVC_POOL_PERCPU:
		pidx = m->to_pool[cpu];
		break;
	case SVC_POOL_PERNODE:
		pidx = m->to_pool[cpu_to_node(cpu)];
		break;
	}
	return &serv->sv_pools[pidx % serv->sv_nrpools];
}


/*
 * Create an RPC service
 */
static struct svc_serv *
__svc_create(struct svc_program *prog, unsigned int bufsize, int npools,
	   void (*shutdown)(struct svc_serv *serv))
{
	struct svc_serv	*serv;
	int vers;
	unsigned int xdrsize;
	unsigned int i;

	if (!(serv = kzalloc(sizeof(*serv), GFP_KERNEL)))
		return NULL;
	serv->sv_name      = prog->pg_name;
	serv->sv_program   = prog;
	serv->sv_nrthreads = 1;
	serv->sv_stats     = prog->pg_stats;
	if (bufsize > RPCSVC_MAXPAYLOAD)
		bufsize = RPCSVC_MAXPAYLOAD;
	serv->sv_max_payload = bufsize? bufsize : 4096;
	serv->sv_max_mesg  = roundup(serv->sv_max_payload + PAGE_SIZE, PAGE_SIZE);
	serv->sv_shutdown  = shutdown;
	xdrsize = 0;
	while (prog) {
		prog->pg_lovers = prog->pg_nvers-1;
		for (vers=0; vers<prog->pg_nvers ; vers++)
			if (prog->pg_vers[vers]) {
				prog->pg_hivers = vers;
				if (prog->pg_lovers > vers)
					prog->pg_lovers = vers;
				if (prog->pg_vers[vers]->vs_xdrsize > xdrsize)
					xdrsize = prog->pg_vers[vers]->vs_xdrsize;
			}
		prog = prog->pg_next;
	}
	serv->sv_xdrsize   = xdrsize;
	INIT_LIST_HEAD(&serv->sv_tempsocks);
	INIT_LIST_HEAD(&serv->sv_permsocks);
	init_timer(&serv->sv_temptimer);
	spin_lock_init(&serv->sv_lock);

	serv->sv_nrpools = npools;
	serv->sv_pools =
		kcalloc(serv->sv_nrpools, sizeof(struct svc_pool),
			GFP_KERNEL);
	if (!serv->sv_pools) {
		kfree(serv);
		return NULL;
	}

	for (i = 0; i < serv->sv_nrpools; i++) {
		struct svc_pool *pool = &serv->sv_pools[i];

		dprintk("initialising pool %u for %s\n",
				i, serv->sv_name);

		pool->sp_id = i;
		INIT_LIST_HEAD(&pool->sp_threads);
		INIT_LIST_HEAD(&pool->sp_sockets);
		INIT_LIST_HEAD(&pool->sp_all_threads);
		spin_lock_init(&pool->sp_lock);
	}


	/* Remove any stale portmap registrations */
	svc_register(serv, 0, 0);

	return serv;
}

struct svc_serv *
svc_create(struct svc_program *prog, unsigned int bufsize,
		void (*shutdown)(struct svc_serv *serv))
{
	return __svc_create(prog, bufsize, /*npools*/1, shutdown);
}

struct svc_serv *
svc_create_pooled(struct svc_program *prog, unsigned int bufsize,
		void (*shutdown)(struct svc_serv *serv),
		  svc_thread_fn func, int sig, struct module *mod)
{
	struct svc_serv *serv;
	unsigned int npools = svc_pool_map_init();

	serv = __svc_create(prog, bufsize, npools, shutdown);

	if (serv != NULL) {
		serv->sv_function = func;
		serv->sv_kill_signal = sig;
		serv->sv_module = mod;
	}

	return serv;
}

/*
 * Destroy an RPC service.  Should be called with the BKL held
 */
void
svc_destroy(struct svc_serv *serv)
{
	struct svc_sock	*svsk;

	dprintk("RPC: svc_destroy(%s, %d)\n",
				serv->sv_program->pg_name,
				serv->sv_nrthreads);

	if (serv->sv_nrthreads) {
		if (--(serv->sv_nrthreads) != 0) {
			svc_sock_update_bufs(serv);
			return;
		}
	} else
		printk("svc_destroy: no threads for serv=%p!\n", serv);

	del_timer_sync(&serv->sv_temptimer);

	while (!list_empty(&serv->sv_tempsocks)) {
		svsk = list_entry(serv->sv_tempsocks.next,
				  struct svc_sock,
				  sk_list);
		svc_delete_socket(svsk);
	}
	if (serv->sv_shutdown)
		serv->sv_shutdown(serv);

	while (!list_empty(&serv->sv_permsocks)) {
		svsk = list_entry(serv->sv_permsocks.next,
				  struct svc_sock,
				  sk_list);
		svc_delete_socket(svsk);
	}
	
	cache_clean_deferred(serv);

	/* Unregister service with the portmapper */
	svc_register(serv, 0, 0);
	kfree(serv->sv_pools);
	kfree(serv);
}

/*
 * Allocate an RPC server's buffer space.
 * We allocate pages and place them in rq_argpages.
 */
static int
svc_init_buffer(struct svc_rqst *rqstp, unsigned int size)
{
	int pages;
	int arghi;
	
	pages = size / PAGE_SIZE + 1; /* extra page as we hold both request and reply.
				       * We assume one is at most one page
				       */
	arghi = 0;
	BUG_ON(pages > RPCSVC_MAXPAGES);
	while (pages) {
		struct page *p = alloc_page(GFP_KERNEL);
		if (!p)
			break;
		rqstp->rq_pages[arghi++] = p;
		pages--;
	}
	return ! pages;
}

/*
 * Release an RPC server buffer
 */
static void
svc_release_buffer(struct svc_rqst *rqstp)
{
	int i;
	for (i=0; i<ARRAY_SIZE(rqstp->rq_pages); i++)
		if (rqstp->rq_pages[i])
			put_page(rqstp->rq_pages[i]);
}

/*
 * Create a thread in the given pool.  Caller must hold BKL.
 * On a NUMA or SMP machine, with a multi-pool serv, the thread
 * will be restricted to run on the cpus belonging to the pool.
 */
static int
__svc_create_thread(svc_thread_fn func, struct svc_serv *serv,
		    struct svc_pool *pool)
{
	struct svc_rqst	*rqstp;
	int		error = -ENOMEM;
	int		have_oldmask = 0;
	cpumask_t	oldmask;

	rqstp = kzalloc(sizeof(*rqstp), GFP_KERNEL);
	if (!rqstp)
		goto out;

	init_waitqueue_head(&rqstp->rq_wait);

	if (!(rqstp->rq_argp = kmalloc(serv->sv_xdrsize, GFP_KERNEL))
	 || !(rqstp->rq_resp = kmalloc(serv->sv_xdrsize, GFP_KERNEL))
	 || !svc_init_buffer(rqstp, serv->sv_max_mesg))
		goto out_thread;

	serv->sv_nrthreads++;
	spin_lock_bh(&pool->sp_lock);
	pool->sp_nrthreads++;
	list_add(&rqstp->rq_all, &pool->sp_all_threads);
	spin_unlock_bh(&pool->sp_lock);
	rqstp->rq_server = serv;
	rqstp->rq_pool = pool;

	if (serv->sv_nrpools > 1)
		have_oldmask = svc_pool_map_set_cpumask(pool->sp_id, &oldmask);

	error = kernel_thread((int (*)(void *)) func, rqstp, 0);

	if (have_oldmask)
		set_cpus_allowed(current, oldmask);

	if (error < 0)
		goto out_thread;
	svc_sock_update_bufs(serv);
	error = 0;
out:
	return error;

out_thread:
	svc_exit_thread(rqstp);
	goto out;
}

/*
 * Create a thread in the default pool.  Caller must hold BKL.
 */
int
svc_create_thread(svc_thread_fn func, struct svc_serv *serv)
{
	return __svc_create_thread(func, serv, &serv->sv_pools[0]);
}

/*
 * Choose a pool in which to create a new thread, for svc_set_num_threads
 */
static inline struct svc_pool *
choose_pool(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
{
	if (pool != NULL)
		return pool;

 	return &serv->sv_pools[(*state)++ % serv->sv_nrpools];
}

/*
 * Choose a thread to kill, for svc_set_num_threads
 */
static inline struct task_struct *
choose_victim(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
{
	unsigned int i;
	struct task_struct *task = NULL;

	if (pool != NULL) {
		spin_lock_bh(&pool->sp_lock);
	} else {
		/* choose a pool in round-robin fashion */
 		for (i = 0; i < serv->sv_nrpools; i++) {
 			pool = &serv->sv_pools[--(*state) % serv->sv_nrpools];
			spin_lock_bh(&pool->sp_lock);
 			if (!list_empty(&pool->sp_all_threads))
 				goto found_pool;
			spin_unlock_bh(&pool->sp_lock);
 		}
		return NULL;
	}

found_pool:
	if (!list_empty(&pool->sp_all_threads)) {
		struct svc_rqst *rqstp;

		/*
		 * Remove from the pool->sp_all_threads list
		 * so we don't try to kill it again.
		 */
		rqstp = list_entry(pool->sp_all_threads.next, struct svc_rqst, rq_all);
		list_del_init(&rqstp->rq_all);
		task = rqstp->rq_task;
    	}
	spin_unlock_bh(&pool->sp_lock);

	return task;
}

/*
 * Create or destroy enough new threads to make the number
 * of threads the given number.  If `pool' is non-NULL, applies
 * only to threads in that pool, otherwise round-robins between
 * all pools.  Must be called with a svc_get() reference and
 * the BKL held.
 *
 * Destroying threads relies on the service threads filling in
 * rqstp->rq_task, which only the nfs ones do.  Assumes the serv
 * has been created using svc_create_pooled().
 *
 * Based on code that used to be in nfsd_svc() but tweaked
 * to be pool-aware.
 */
int
svc_set_num_threads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
{
	struct task_struct *victim;
	int error = 0;
	unsigned int state = serv->sv_nrthreads-1;

	if (pool == NULL) {
		/* The -1 assumes caller has done a svc_get() */
		nrservs -= (serv->sv_nrthreads-1);
	} else {
		spin_lock_bh(&pool->sp_lock);
		nrservs -= pool->sp_nrthreads;
		spin_unlock_bh(&pool->sp_lock);
	}

	/* create new threads */
	while (nrservs > 0) {
		nrservs--;
		__module_get(serv->sv_module);
		error = __svc_create_thread(serv->sv_function, serv,
					    choose_pool(serv, pool, &state));
		if (error < 0) {
			module_put(serv->sv_module);
			break;
		}
	}
	/* destroy old threads */
	while (nrservs < 0 &&
	       (victim = choose_victim(serv, pool, &state)) != NULL) {
		send_sig(serv->sv_kill_signal, victim, 1);
		nrservs++;
	}

	return error;
}

/*
 * Called from a server thread as it's exiting.  Caller must hold BKL.
 */
void
svc_exit_thread(struct svc_rqst *rqstp)
{
	struct svc_serv	*serv = rqstp->rq_server;
	struct svc_pool	*pool = rqstp->rq_pool;

	svc_release_buffer(rqstp);
	kfree(rqstp->rq_resp);
	kfree(rqstp->rq_argp);
	kfree(rqstp->rq_auth_data);

	spin_lock_bh(&pool->sp_lock);
	pool->sp_nrthreads--;
	list_del(&rqstp->rq_all);
	spin_unlock_bh(&pool->sp_lock);

	kfree(rqstp);

	/* Release the server */
	if (serv)
		svc_destroy(serv);
}

/*
 * Register an RPC service with the local portmapper.
 * To unregister a service, call this routine with 
 * proto and port == 0.
 */
int
svc_register(struct svc_serv *serv, int proto, unsigned short port)
{
	struct svc_program	*progp;
	unsigned long		flags;
	int			i, error = 0, dummy;

	if (!port)
		clear_thread_flag(TIF_SIGPENDING);

	for (progp = serv->sv_program; progp; progp = progp->pg_next) {
		for (i = 0; i < progp->pg_nvers; i++) {
			if (progp->pg_vers[i] == NULL)
				continue;

			dprintk("RPC: svc_register(%s, %s, %d, %d)%s\n",
					progp->pg_name,
					proto == IPPROTO_UDP?  "udp" : "tcp",
					port,
					i,
					progp->pg_vers[i]->vs_hidden?
						" (but not telling portmap)" : "");

			if (progp->pg_vers[i]->vs_hidden)
				continue;

			error = rpc_register(progp->pg_prog, i, proto, port, &dummy);
			if (error < 0)
				break;
			if (port && !dummy) {
				error = -EACCES;
				break;
			}
		}
	}

	if (!port) {
		spin_lock_irqsave(&current->sighand->siglock, flags);
		recalc_sigpending();
		spin_unlock_irqrestore(&current->sighand->siglock, flags);
	}

	return error;
}

/*
 * Process the RPC request.
 */
int
svc_process(struct svc_rqst *rqstp)
{
	struct svc_program	*progp;
	struct svc_version	*versp = NULL;	/* compiler food */
	struct svc_procedure	*procp = NULL;
	struct kvec *		argv = &rqstp->rq_arg.head[0];
	struct kvec *		resv = &rqstp->rq_res.head[0];
	struct svc_serv		*serv = rqstp->rq_server;
	kxdrproc_t		xdr;
	__be32			*statp;
	u32			dir, prog, vers, proc;
	__be32			auth_stat, rpc_stat;
	int			auth_res;
	__be32			*reply_statp;

	rpc_stat = rpc_success;

	if (argv->iov_len < 6*4)
		goto err_short_len;

	/* setup response xdr_buf.
	 * Initially it has just one page 
	 */
	rqstp->rq_resused = 1;
	resv->iov_base = page_address(rqstp->rq_respages[0]);
	resv->iov_len = 0;
	rqstp->rq_res.pages = rqstp->rq_respages + 1;
	rqstp->rq_res.len = 0;
	rqstp->rq_res.page_base = 0;
	rqstp->rq_res.page_len = 0;
	rqstp->rq_res.buflen = PAGE_SIZE;
	rqstp->rq_res.tail[0].iov_base = NULL;
	rqstp->rq_res.tail[0].iov_len = 0;
	/* Will be turned off only in gss privacy case: */
	rqstp->rq_sendfile_ok = 1;
	/* tcp needs a space for the record length... */
	if (rqstp->rq_prot == IPPROTO_TCP)
		svc_putnl(resv, 0);

	rqstp->rq_xid = svc_getu32(argv);
	svc_putu32(resv, rqstp->rq_xid);

	dir  = svc_getnl(argv);
	vers = svc_getnl(argv);

	/* First words of reply: */
	svc_putnl(resv, 1);		/* REPLY */

	if (dir != 0)		/* direction != CALL */
		goto err_bad_dir;
	if (vers != 2)		/* RPC version number */
		goto err_bad_rpc;

	/* Save position in case we later decide to reject: */
	reply_statp = resv->iov_base + resv->iov_len;

	svc_putnl(resv, 0);		/* ACCEPT */

	rqstp->rq_prog = prog = svc_getnl(argv);	/* program number */
	rqstp->rq_vers = vers = svc_getnl(argv);	/* version number */
	rqstp->rq_proc = proc = svc_getnl(argv);	/* procedure number */

	progp = serv->sv_program;

	for (progp = serv->sv_program; progp; progp = progp->pg_next)
		if (prog == progp->pg_prog)
			break;

	/*
	 * Decode auth data, and add verifier to reply buffer.
	 * We do this before anything else in order to get a decent
	 * auth verifier.
	 */
	auth_res = svc_authenticate(rqstp, &auth_stat);
	/* Also give the program a chance to reject this call: */
	if (auth_res == SVC_OK && progp) {
		auth_stat = rpc_autherr_badcred;
		auth_res = progp->pg_authenticate(rqstp);
	}
	switch (auth_res) {
	case SVC_OK:
		break;
	case SVC_GARBAGE:
		rpc_stat = rpc_garbage_args;
		goto err_bad;
	case SVC_SYSERR:
		rpc_stat = rpc_system_err;
		goto err_bad;
	case SVC_DENIED:
		goto err_bad_auth;
	case SVC_DROP:
		goto dropit;
	case SVC_COMPLETE:
		goto sendit;
	}

	if (progp == NULL)
		goto err_bad_prog;

	if (vers >= progp->pg_nvers ||
	  !(versp = progp->pg_vers[vers]))
		goto err_bad_vers;

	procp = versp->vs_proc + proc;
	if (proc >= versp->vs_nproc || !procp->pc_func)
		goto err_bad_proc;
	rqstp->rq_server   = serv;
	rqstp->rq_procinfo = procp;

	/* Syntactic check complete */
	serv->sv_stats->rpccnt++;

	/* Build the reply header. */
	statp = resv->iov_base +resv->iov_len;
	svc_putnl(resv, RPC_SUCCESS);

	/* Bump per-procedure stats counter */
	procp->pc_count++;

	/* Initialize storage for argp and resp */
	memset(rqstp->rq_argp, 0, procp->pc_argsize);
	memset(rqstp->rq_resp, 0, procp->pc_ressize);

	/* un-reserve some of the out-queue now that we have a 
	 * better idea of reply size
	 */
	if (procp->pc_xdrressize)
		svc_reserve(rqstp, procp->pc_xdrressize<<2);

	/* Call the function that processes the request. */
	if (!versp->vs_dispatch) {
		/* Decode arguments */
		xdr = procp->pc_decode;
		if (xdr && !xdr(rqstp, argv->iov_base, rqstp->rq_argp))
			goto err_garbage;

		*statp = procp->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);

		/* Encode reply */
		if (*statp == rpc_drop_reply) {
			if (procp->pc_release)
				procp->pc_release(rqstp, NULL, rqstp->rq_resp);
			goto dropit;
		}
		if (*statp == rpc_success && (xdr = procp->pc_encode)
		 && !xdr(rqstp, resv->iov_base+resv->iov_len, rqstp->rq_resp)) {
			dprintk("svc: failed to encode reply\n");
			/* serv->sv_stats->rpcsystemerr++; */
			*statp = rpc_system_err;
		}
	} else {
		dprintk("svc: calling dispatcher\n");
		if (!versp->vs_dispatch(rqstp, statp)) {
			/* Release reply info */
			if (procp->pc_release)
				procp->pc_release(rqstp, NULL, rqstp->rq_resp);
			goto dropit;
		}
	}

	/* Check RPC status result */
	if (*statp != rpc_success)
		resv->iov_len = ((void*)statp)  - resv->iov_base + 4;

	/* Release reply info */
	if (procp->pc_release)
		procp->pc_release(rqstp, NULL, rqstp->rq_resp);

	if (procp->pc_encode == NULL)
		goto dropit;

 sendit:
	if (svc_authorise(rqstp))
		goto dropit;
	return svc_send(rqstp);

 dropit:
	svc_authorise(rqstp);	/* doesn't hurt to call this twice */
	dprintk("svc: svc_process dropit\n");
	svc_drop(rqstp);
	return 0;

err_short_len:
#ifdef RPC_PARANOIA
	printk("svc: short len %Zd, dropping request\n", argv->iov_len);
#endif
	goto dropit;			/* drop request */

err_bad_dir:
#ifdef RPC_PARANOIA
	printk("svc: bad direction %d, dropping request\n", dir);
#endif
	serv->sv_stats->rpcbadfmt++;
	goto dropit;			/* drop request */

err_bad_rpc:
	serv->sv_stats->rpcbadfmt++;
	svc_putnl(resv, 1);	/* REJECT */
	svc_putnl(resv, 0);	/* RPC_MISMATCH */
	svc_putnl(resv, 2);	/* Only RPCv2 supported */
	svc_putnl(resv, 2);
	goto sendit;

err_bad_auth:
	dprintk("svc: authentication failed (%d)\n", ntohl(auth_stat));
	serv->sv_stats->rpcbadauth++;
	/* Restore write pointer to location of accept status: */
	xdr_ressize_check(rqstp, reply_statp);
	svc_putnl(resv, 1);	/* REJECT */
	svc_putnl(resv, 1);	/* AUTH_ERROR */
	svc_putnl(resv, ntohl(auth_stat));	/* status */
	goto sendit;

err_bad_prog:
	dprintk("svc: unknown program %d\n", prog);
	serv->sv_stats->rpcbadfmt++;
	svc_putnl(resv, RPC_PROG_UNAVAIL);
	goto sendit;

err_bad_vers:
#ifdef RPC_PARANOIA
	printk("svc: unknown version (%d)\n", vers);
#endif
	serv->sv_stats->rpcbadfmt++;
	svc_putnl(resv, RPC_PROG_MISMATCH);
	svc_putnl(resv, progp->pg_lovers);
	svc_putnl(resv, progp->pg_hivers);
	goto sendit;

err_bad_proc:
#ifdef RPC_PARANOIA
	printk("svc: unknown procedure (%d)\n", proc);
#endif
	serv->sv_stats->rpcbadfmt++;
	svc_putnl(resv, RPC_PROC_UNAVAIL);
	goto sendit;

err_garbage:
#ifdef RPC_PARANOIA
	printk("svc: failed to decode args\n");
#endif
	rpc_stat = rpc_garbage_args;
err_bad:
	serv->sv_stats->rpcbadfmt++;
	svc_putnl(resv, ntohl(rpc_stat));
	goto sendit;
}

/*
 * Return (transport-specific) limit on the rpc payload.
 */
u32 svc_max_payload(const struct svc_rqst *rqstp)
{
	int max = RPCSVC_MAXPAYLOAD_TCP;

	if (rqstp->rq_sock->sk_sock->type == SOCK_DGRAM)
		max = RPCSVC_MAXPAYLOAD_UDP;
	if (rqstp->rq_server->sv_max_payload < max)
		max = rqstp->rq_server->sv_max_payload;
	return max;
}
EXPORT_SYMBOL_GPL(svc_max_payload);
OpenPOWER on IntegriCloud