forked from torvalds/linux
-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathclient.c
2314 lines (1968 loc) · 54.3 KB
/
client.c
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
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
// SPDX-License-Identifier: GPL-2.0-only
/*
* 9P Client
*
* Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
* Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/poll.h>
#include <linux/idr.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/sched/signal.h>
#include <linux/uaccess.h>
#include <linux/uio.h>
#include <linux/netfs.h>
#include <net/9p/9p.h>
#include <linux/parser.h>
#include <linux/seq_file.h>
#include <net/9p/client.h>
#include <net/9p/transport.h>
#include "protocol.h"
#define CREATE_TRACE_POINTS
#include <trace/events/9p.h>
/* DEFAULT MSIZE = 32 pages worth of payload + P9_HDRSZ +
* room for write (16 extra) or read (11 extra) operands.
*/
#define DEFAULT_MSIZE ((128 * 1024) + P9_IOHDRSZ)
/* Client Option Parsing (code inspired by NFS code)
* - a little lazy - parse all client options
*/
enum {
Opt_msize,
Opt_trans,
Opt_legacy,
Opt_version,
Opt_err,
};
static const match_table_t tokens = {
{Opt_msize, "msize=%u"},
{Opt_legacy, "noextend"},
{Opt_trans, "trans=%s"},
{Opt_version, "version=%s"},
{Opt_err, NULL},
};
inline int p9_is_proto_dotl(struct p9_client *clnt)
{
return clnt->proto_version == p9_proto_2000L;
}
EXPORT_SYMBOL(p9_is_proto_dotl);
inline int p9_is_proto_dotu(struct p9_client *clnt)
{
return clnt->proto_version == p9_proto_2000u;
}
EXPORT_SYMBOL(p9_is_proto_dotu);
int p9_show_client_options(struct seq_file *m, struct p9_client *clnt)
{
if (clnt->msize != DEFAULT_MSIZE)
seq_printf(m, ",msize=%u", clnt->msize);
seq_printf(m, ",trans=%s", clnt->trans_mod->name);
switch (clnt->proto_version) {
case p9_proto_legacy:
seq_puts(m, ",noextend");
break;
case p9_proto_2000u:
seq_puts(m, ",version=9p2000.u");
break;
case p9_proto_2000L:
/* Default */
break;
}
if (clnt->trans_mod->show_options)
return clnt->trans_mod->show_options(m, clnt);
return 0;
}
EXPORT_SYMBOL(p9_show_client_options);
/* Some error codes are taken directly from the server replies,
* make sure they are valid.
*/
static int safe_errno(int err)
{
if (err > 0 || err < -MAX_ERRNO) {
p9_debug(P9_DEBUG_ERROR, "Invalid error code %d\n", err);
return -EPROTO;
}
return err;
}
/* Interpret mount option for protocol version */
static int get_protocol_version(char *s)
{
int version = -EINVAL;
if (!strcmp(s, "9p2000")) {
version = p9_proto_legacy;
p9_debug(P9_DEBUG_9P, "Protocol version: Legacy\n");
} else if (!strcmp(s, "9p2000.u")) {
version = p9_proto_2000u;
p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.u\n");
} else if (!strcmp(s, "9p2000.L")) {
version = p9_proto_2000L;
p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.L\n");
} else {
pr_info("Unknown protocol version %s\n", s);
}
return version;
}
/**
* parse_opts - parse mount options into client structure
* @opts: options string passed from mount
* @clnt: existing v9fs client information
*
* Return 0 upon success, -ERRNO upon failure
*/
static int parse_opts(char *opts, struct p9_client *clnt)
{
char *options, *tmp_options;
char *p;
substring_t args[MAX_OPT_ARGS];
int option;
char *s;
int ret = 0;
clnt->proto_version = p9_proto_2000L;
clnt->msize = DEFAULT_MSIZE;
if (!opts)
return 0;
tmp_options = kstrdup(opts, GFP_KERNEL);
if (!tmp_options)
return -ENOMEM;
options = tmp_options;
while ((p = strsep(&options, ",")) != NULL) {
int token, r;
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_msize:
r = match_int(&args[0], &option);
if (r < 0) {
p9_debug(P9_DEBUG_ERROR,
"integer field, but no integer?\n");
ret = r;
continue;
}
if (option < 4096) {
p9_debug(P9_DEBUG_ERROR,
"msize should be at least 4k\n");
ret = -EINVAL;
continue;
}
clnt->msize = option;
break;
case Opt_trans:
s = match_strdup(&args[0]);
if (!s) {
ret = -ENOMEM;
p9_debug(P9_DEBUG_ERROR,
"problem allocating copy of trans arg\n");
goto free_and_return;
}
v9fs_put_trans(clnt->trans_mod);
clnt->trans_mod = v9fs_get_trans_by_name(s);
if (!clnt->trans_mod) {
pr_info("Could not find request transport: %s\n",
s);
ret = -EINVAL;
}
kfree(s);
break;
case Opt_legacy:
clnt->proto_version = p9_proto_legacy;
break;
case Opt_version:
s = match_strdup(&args[0]);
if (!s) {
ret = -ENOMEM;
p9_debug(P9_DEBUG_ERROR,
"problem allocating copy of version arg\n");
goto free_and_return;
}
r = get_protocol_version(s);
if (r < 0)
ret = r;
else
clnt->proto_version = r;
kfree(s);
break;
default:
continue;
}
}
free_and_return:
if (ret)
v9fs_put_trans(clnt->trans_mod);
kfree(tmp_options);
return ret;
}
static int p9_fcall_init(struct p9_client *c, struct p9_fcall *fc,
int alloc_msize)
{
if (likely(c->fcall_cache) && alloc_msize == c->msize) {
fc->sdata = kmem_cache_alloc(c->fcall_cache, GFP_NOFS);
fc->cache = c->fcall_cache;
} else {
fc->sdata = kmalloc(alloc_msize, GFP_NOFS);
fc->cache = NULL;
}
if (!fc->sdata)
return -ENOMEM;
fc->capacity = alloc_msize;
fc->id = 0;
fc->tag = P9_NOTAG;
return 0;
}
void p9_fcall_fini(struct p9_fcall *fc)
{
/* sdata can be NULL for interrupted requests in trans_rdma,
* and kmem_cache_free does not do NULL-check for us
*/
if (unlikely(!fc->sdata))
return;
if (fc->cache)
kmem_cache_free(fc->cache, fc->sdata);
else
kfree(fc->sdata);
}
EXPORT_SYMBOL(p9_fcall_fini);
static struct kmem_cache *p9_req_cache;
/**
* p9_tag_alloc - Allocate a new request.
* @c: Client session.
* @type: Transaction type.
* @t_size: Buffer size for holding this request
* (automatic calculation by format template if 0).
* @r_size: Buffer size for holding server's reply on this request
* (automatic calculation by format template if 0).
* @fmt: Format template for assembling 9p request message
* (see p9pdu_vwritef).
* @ap: Variable arguments to be fed to passed format template
* (see p9pdu_vwritef).
*
* Context: Process context.
* Return: Pointer to new request.
*/
static struct p9_req_t *
p9_tag_alloc(struct p9_client *c, int8_t type, uint t_size, uint r_size,
const char *fmt, va_list ap)
{
struct p9_req_t *req = kmem_cache_alloc(p9_req_cache, GFP_NOFS);
int alloc_tsize;
int alloc_rsize;
int tag;
va_list apc;
va_copy(apc, ap);
alloc_tsize = min_t(size_t, c->msize,
t_size ?: p9_msg_buf_size(c, type, fmt, apc));
va_end(apc);
alloc_rsize = min_t(size_t, c->msize,
r_size ?: p9_msg_buf_size(c, type + 1, fmt, ap));
if (!req)
return ERR_PTR(-ENOMEM);
if (p9_fcall_init(c, &req->tc, alloc_tsize))
goto free_req;
if (p9_fcall_init(c, &req->rc, alloc_rsize))
goto free;
p9pdu_reset(&req->tc);
p9pdu_reset(&req->rc);
req->t_err = 0;
req->status = REQ_STATUS_ALLOC;
/* refcount needs to be set to 0 before inserting into the idr
* so p9_tag_lookup does not accept a request that is not fully
* initialized. refcount_set to 2 below will mark request ready.
*/
refcount_set(&req->refcount, 0);
init_waitqueue_head(&req->wq);
INIT_LIST_HEAD(&req->req_list);
idr_preload(GFP_NOFS);
spin_lock_irq(&c->lock);
if (type == P9_TVERSION)
tag = idr_alloc(&c->reqs, req, P9_NOTAG, P9_NOTAG + 1,
GFP_NOWAIT);
else
tag = idr_alloc(&c->reqs, req, 0, P9_NOTAG, GFP_NOWAIT);
req->tc.tag = tag;
spin_unlock_irq(&c->lock);
idr_preload_end();
if (tag < 0)
goto free;
/* Init ref to two because in the general case there is one ref
* that is put asynchronously by a writer thread, one ref
* temporarily given by p9_tag_lookup and put by p9_client_cb
* in the recv thread, and one ref put by p9_req_put in the
* main thread. The only exception is virtio that does not use
* p9_tag_lookup but does not have a writer thread either
* (the write happens synchronously in the request/zc_request
* callback), so p9_client_cb eats the second ref there
* as the pointer is duplicated directly by virtqueue_add_sgs()
*/
refcount_set(&req->refcount, 2);
return req;
free:
p9_fcall_fini(&req->tc);
p9_fcall_fini(&req->rc);
free_req:
kmem_cache_free(p9_req_cache, req);
return ERR_PTR(-ENOMEM);
}
/**
* p9_tag_lookup - Look up a request by tag.
* @c: Client session.
* @tag: Transaction ID.
*
* Context: Any context.
* Return: A request, or %NULL if there is no request with that tag.
*/
struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
{
struct p9_req_t *req;
rcu_read_lock();
again:
req = idr_find(&c->reqs, tag);
if (req) {
/* We have to be careful with the req found under rcu_read_lock
* Thanks to SLAB_TYPESAFE_BY_RCU we can safely try to get the
* ref again without corrupting other data, then check again
* that the tag matches once we have the ref
*/
if (!p9_req_try_get(req))
goto again;
if (req->tc.tag != tag) {
p9_req_put(c, req);
goto again;
}
}
rcu_read_unlock();
return req;
}
EXPORT_SYMBOL(p9_tag_lookup);
/**
* p9_tag_remove - Remove a tag.
* @c: Client session.
* @r: Request of reference.
*
* Context: Any context.
*/
static void p9_tag_remove(struct p9_client *c, struct p9_req_t *r)
{
unsigned long flags;
u16 tag = r->tc.tag;
p9_debug(P9_DEBUG_MUX, "freeing clnt %p req %p tag: %d\n", c, r, tag);
spin_lock_irqsave(&c->lock, flags);
idr_remove(&c->reqs, tag);
spin_unlock_irqrestore(&c->lock, flags);
}
int p9_req_put(struct p9_client *c, struct p9_req_t *r)
{
if (refcount_dec_and_test(&r->refcount)) {
p9_tag_remove(c, r);
p9_fcall_fini(&r->tc);
p9_fcall_fini(&r->rc);
kmem_cache_free(p9_req_cache, r);
return 1;
}
return 0;
}
EXPORT_SYMBOL(p9_req_put);
/**
* p9_tag_cleanup - cleans up tags structure and reclaims resources
* @c: v9fs client struct
*
* This frees resources associated with the tags structure
*
*/
static void p9_tag_cleanup(struct p9_client *c)
{
struct p9_req_t *req;
int id;
rcu_read_lock();
idr_for_each_entry(&c->reqs, req, id) {
pr_info("Tag %d still in use\n", id);
if (p9_req_put(c, req) == 0)
pr_warn("Packet with tag %d has still references",
req->tc.tag);
}
rcu_read_unlock();
}
/**
* p9_client_cb - call back from transport to client
* @c: client state
* @req: request received
* @status: request status, one of REQ_STATUS_*
*
*/
void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
{
p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc.tag);
/* This barrier is needed to make sure any change made to req before
* the status change is visible to another thread
*/
smp_wmb();
WRITE_ONCE(req->status, status);
wake_up(&req->wq);
p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc.tag);
p9_req_put(c, req);
}
EXPORT_SYMBOL(p9_client_cb);
/**
* p9_parse_header - parse header arguments out of a packet
* @pdu: packet to parse
* @size: size of packet
* @type: type of request
* @tag: tag of packet
* @rewind: set if we need to rewind offset afterwards
*/
int
p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type,
int16_t *tag, int rewind)
{
s8 r_type;
s16 r_tag;
s32 r_size;
int offset = pdu->offset;
int err;
pdu->offset = 0;
err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
if (err)
goto rewind_and_exit;
if (type)
*type = r_type;
if (tag)
*tag = r_tag;
if (size)
*size = r_size;
if (pdu->size != r_size || r_size < 7) {
err = -EINVAL;
goto rewind_and_exit;
}
pdu->id = r_type;
pdu->tag = r_tag;
p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",
pdu->size, pdu->id, pdu->tag);
rewind_and_exit:
if (rewind)
pdu->offset = offset;
return err;
}
EXPORT_SYMBOL(p9_parse_header);
/**
* p9_check_errors - check 9p packet for error return and process it
* @c: current client instance
* @req: request to parse and check for error conditions
*
* returns error code if one is discovered, otherwise returns 0
*
* this will have to be more complicated if we have multiple
* error packet types
*/
static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
{
s8 type;
int err;
int ecode;
err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
if (req->rc.size > req->rc.capacity && !req->rc.zc) {
pr_err("requested packet size too big: %d does not fit %zu (type=%d)\n",
req->rc.size, req->rc.capacity, req->rc.id);
return -EIO;
}
/* dump the response from server
* This should be after check errors which poplulate pdu_fcall.
*/
trace_9p_protocol_dump(c, &req->rc);
if (err) {
p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
return err;
}
if (type != P9_RERROR && type != P9_RLERROR)
return 0;
if (!p9_is_proto_dotl(c)) {
char *ename = NULL;
err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
&ename, &ecode);
if (err) {
kfree(ename);
goto out_err;
}
if (p9_is_proto_dotu(c) && ecode < 512)
err = -ecode;
if (!err) {
err = p9_errstr2errno(ename, strlen(ename));
p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
-ecode, ename);
}
kfree(ename);
} else {
err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
if (err)
goto out_err;
err = -ecode;
p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
}
return err;
out_err:
p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
return err;
}
static struct p9_req_t *
p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
/**
* p9_client_flush - flush (cancel) a request
* @c: client state
* @oldreq: request to cancel
*
* This sents a flush for a particular request and links
* the flush request to the original request. The current
* code only supports a single flush request although the protocol
* allows for multiple flush requests to be sent for a single request.
*
*/
static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
{
struct p9_req_t *req;
s16 oldtag;
int err;
err = p9_parse_header(&oldreq->tc, NULL, NULL, &oldtag, 1);
if (err)
return err;
p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
if (IS_ERR(req))
return PTR_ERR(req);
/* if we haven't received a response for oldreq,
* remove it from the list
*/
if (READ_ONCE(oldreq->status) == REQ_STATUS_SENT) {
if (c->trans_mod->cancelled)
c->trans_mod->cancelled(c, oldreq);
}
p9_req_put(c, req);
return 0;
}
static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
int8_t type, uint t_size, uint r_size,
const char *fmt, va_list ap)
{
int err;
struct p9_req_t *req;
va_list apc;
p9_debug(P9_DEBUG_MUX, "client %p op %d\n", c, type);
/* we allow for any status other than disconnected */
if (c->status == Disconnected)
return ERR_PTR(-EIO);
/* if status is begin_disconnected we allow only clunk request */
if (c->status == BeginDisconnect && type != P9_TCLUNK)
return ERR_PTR(-EIO);
va_copy(apc, ap);
req = p9_tag_alloc(c, type, t_size, r_size, fmt, apc);
va_end(apc);
if (IS_ERR(req))
return req;
/* marshall the data */
p9pdu_prepare(&req->tc, req->tc.tag, type);
err = p9pdu_vwritef(&req->tc, c->proto_version, fmt, ap);
if (err)
goto reterr;
p9pdu_finalize(c, &req->tc);
trace_9p_client_req(c, type, req->tc.tag);
return req;
reterr:
p9_req_put(c, req);
/* We have to put also the 2nd reference as it won't be used */
p9_req_put(c, req);
return ERR_PTR(err);
}
/**
* p9_client_rpc - issue a request and wait for a response
* @c: client session
* @type: type of request
* @fmt: protocol format string (see protocol.c)
*
* Returns request structure (which client must free using p9_req_put)
*/
static struct p9_req_t *
p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
{
va_list ap;
int sigpending, err;
unsigned long flags;
struct p9_req_t *req;
/* Passing zero for tsize/rsize to p9_client_prepare_req() tells it to
* auto determine an appropriate (small) request/response size
* according to actual message data being sent. Currently RDMA
* transport is excluded from this response message size optimization,
* as it would not cope with it, due to its pooled response buffers
* (using an optimized request size for RDMA as well though).
*/
const uint tsize = 0;
const uint rsize = c->trans_mod->pooled_rbuffers ? c->msize : 0;
va_start(ap, fmt);
req = p9_client_prepare_req(c, type, tsize, rsize, fmt, ap);
va_end(ap);
if (IS_ERR(req))
return req;
req->tc.zc = false;
req->rc.zc = false;
if (signal_pending(current)) {
sigpending = 1;
clear_thread_flag(TIF_SIGPENDING);
} else {
sigpending = 0;
}
err = c->trans_mod->request(c, req);
if (err < 0) {
/* write won't happen */
p9_req_put(c, req);
if (err != -ERESTARTSYS && err != -EFAULT)
c->status = Disconnected;
goto recalc_sigpending;
}
again:
/* Wait for the response */
err = wait_event_killable(req->wq,
READ_ONCE(req->status) >= REQ_STATUS_RCVD);
/* Make sure our req is coherent with regard to updates in other
* threads - echoes to wmb() in the callback
*/
smp_rmb();
if (err == -ERESTARTSYS && c->status == Connected &&
type == P9_TFLUSH) {
sigpending = 1;
clear_thread_flag(TIF_SIGPENDING);
goto again;
}
if (READ_ONCE(req->status) == REQ_STATUS_ERROR) {
p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
err = req->t_err;
}
if (err == -ERESTARTSYS && c->status == Connected) {
p9_debug(P9_DEBUG_MUX, "flushing\n");
sigpending = 1;
clear_thread_flag(TIF_SIGPENDING);
if (c->trans_mod->cancel(c, req))
p9_client_flush(c, req);
/* if we received the response anyway, don't signal error */
if (READ_ONCE(req->status) == REQ_STATUS_RCVD)
err = 0;
}
recalc_sigpending:
if (sigpending) {
spin_lock_irqsave(¤t->sighand->siglock, flags);
recalc_sigpending();
spin_unlock_irqrestore(¤t->sighand->siglock, flags);
}
if (err < 0)
goto reterr;
err = p9_check_errors(c, req);
trace_9p_client_res(c, type, req->rc.tag, err);
if (!err)
return req;
reterr:
p9_req_put(c, req);
return ERR_PTR(safe_errno(err));
}
/**
* p9_client_zc_rpc - issue a request and wait for a response
* @c: client session
* @type: type of request
* @uidata: destination for zero copy read
* @uodata: source for zero copy write
* @inlen: read buffer size
* @olen: write buffer size
* @in_hdrlen: reader header size, This is the size of response protocol data
* @fmt: protocol format string (see protocol.c)
*
* Returns request structure (which client must free using p9_req_put)
*/
static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
struct iov_iter *uidata,
struct iov_iter *uodata,
int inlen, int olen, int in_hdrlen,
const char *fmt, ...)
{
va_list ap;
int sigpending, err;
unsigned long flags;
struct p9_req_t *req;
va_start(ap, fmt);
/* We allocate a inline protocol data of only 4k bytes.
* The actual content is passed in zero-copy fashion.
*/
req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, P9_ZC_HDR_SZ, fmt, ap);
va_end(ap);
if (IS_ERR(req))
return req;
req->tc.zc = true;
req->rc.zc = true;
if (signal_pending(current)) {
sigpending = 1;
clear_thread_flag(TIF_SIGPENDING);
} else {
sigpending = 0;
}
err = c->trans_mod->zc_request(c, req, uidata, uodata,
inlen, olen, in_hdrlen);
if (err < 0) {
if (err == -EIO)
c->status = Disconnected;
if (err != -ERESTARTSYS)
goto recalc_sigpending;
}
if (READ_ONCE(req->status) == REQ_STATUS_ERROR) {
p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
err = req->t_err;
}
if (err == -ERESTARTSYS && c->status == Connected) {
p9_debug(P9_DEBUG_MUX, "flushing\n");
sigpending = 1;
clear_thread_flag(TIF_SIGPENDING);
if (c->trans_mod->cancel(c, req))
p9_client_flush(c, req);
/* if we received the response anyway, don't signal error */
if (READ_ONCE(req->status) == REQ_STATUS_RCVD)
err = 0;
}
recalc_sigpending:
if (sigpending) {
spin_lock_irqsave(¤t->sighand->siglock, flags);
recalc_sigpending();
spin_unlock_irqrestore(¤t->sighand->siglock, flags);
}
if (err < 0)
goto reterr;
err = p9_check_errors(c, req);
trace_9p_client_res(c, type, req->rc.tag, err);
if (!err)
return req;
reterr:
p9_req_put(c, req);
return ERR_PTR(safe_errno(err));
}
static struct p9_fid *p9_fid_create(struct p9_client *clnt)
{
int ret;
struct p9_fid *fid;
p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
fid = kzalloc(sizeof(*fid), GFP_KERNEL);
if (!fid)
return NULL;
fid->mode = -1;
fid->uid = current_fsuid();
fid->clnt = clnt;
refcount_set(&fid->count, 1);
idr_preload(GFP_KERNEL);
spin_lock_irq(&clnt->lock);
ret = idr_alloc_u32(&clnt->fids, fid, &fid->fid, P9_NOFID - 1,
GFP_NOWAIT);
spin_unlock_irq(&clnt->lock);
idr_preload_end();
if (!ret) {
trace_9p_fid_ref(fid, P9_FID_REF_CREATE);
return fid;
}
kfree(fid);
return NULL;
}
static void p9_fid_destroy(struct p9_fid *fid)
{
struct p9_client *clnt;
unsigned long flags;
p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
trace_9p_fid_ref(fid, P9_FID_REF_DESTROY);
clnt = fid->clnt;
spin_lock_irqsave(&clnt->lock, flags);
idr_remove(&clnt->fids, fid->fid);
spin_unlock_irqrestore(&clnt->lock, flags);
kfree(fid->rdir);
kfree(fid);
}
/* We also need to export tracepoint symbols for tracepoint_enabled() */
EXPORT_TRACEPOINT_SYMBOL(9p_fid_ref);
void do_trace_9p_fid_get(struct p9_fid *fid)
{
trace_9p_fid_ref(fid, P9_FID_REF_GET);
}
EXPORT_SYMBOL(do_trace_9p_fid_get);
void do_trace_9p_fid_put(struct p9_fid *fid)
{
trace_9p_fid_ref(fid, P9_FID_REF_PUT);
}
EXPORT_SYMBOL(do_trace_9p_fid_put);
static int p9_client_version(struct p9_client *c)
{
int err;
struct p9_req_t *req;
char *version = NULL;
int msize;
p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
c->msize, c->proto_version);
switch (c->proto_version) {
case p9_proto_2000L:
req = p9_client_rpc(c, P9_TVERSION, "ds",
c->msize, "9P2000.L");
break;
case p9_proto_2000u:
req = p9_client_rpc(c, P9_TVERSION, "ds",
c->msize, "9P2000.u");
break;
case p9_proto_legacy:
req = p9_client_rpc(c, P9_TVERSION, "ds",
c->msize, "9P2000");
break;
default:
return -EINVAL;
}
if (IS_ERR(req))
return PTR_ERR(req);
err = p9pdu_readf(&req->rc, c->proto_version, "ds", &msize, &version);
if (err) {
p9_debug(P9_DEBUG_9P, "version error %d\n", err);
trace_9p_protocol_dump(c, &req->rc);
goto error;
}
p9_debug(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
if (!strncmp(version, "9P2000.L", 8)) {
c->proto_version = p9_proto_2000L;
} else if (!strncmp(version, "9P2000.u", 8)) {
c->proto_version = p9_proto_2000u;
} else if (!strncmp(version, "9P2000", 6)) {
c->proto_version = p9_proto_legacy;
} else {
p9_debug(P9_DEBUG_ERROR,
"server returned an unknown version: %s\n", version);
err = -EREMOTEIO;
goto error;
}
if (msize < 4096) {
p9_debug(P9_DEBUG_ERROR,
"server returned a msize < 4096: %d\n", msize);
err = -EREMOTEIO;
goto error;
}
if (msize < c->msize)
c->msize = msize;
error:
kfree(version);
p9_req_put(c, req);
return err;
}
struct p9_client *p9_client_create(const char *dev_name, char *options)
{
int err;
struct p9_client *clnt;
char *client_id;
clnt = kmalloc(sizeof(*clnt), GFP_KERNEL);
if (!clnt)
return ERR_PTR(-ENOMEM);
clnt->trans_mod = NULL;
clnt->trans = NULL;
clnt->fcall_cache = NULL;
client_id = utsname()->nodename;
memcpy(clnt->name, client_id, strlen(client_id) + 1);
spin_lock_init(&clnt->lock);
idr_init(&clnt->fids);
idr_init(&clnt->reqs);
err = parse_opts(options, clnt);
if (err < 0)
goto free_client;