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CommitLineData
1da177e4
LT
1/*
2 * linux/net/sunrpc/xdr.c
3 *
4 * Generic XDR support.
5 *
6 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
7 */
8
a246b010 9#include <linux/module.h>
5a0e3ad6 10#include <linux/slab.h>
1da177e4 11#include <linux/types.h>
1da177e4
LT
12#include <linux/string.h>
13#include <linux/kernel.h>
14#include <linux/pagemap.h>
15#include <linux/errno.h>
1da177e4
LT
16#include <linux/sunrpc/xdr.h>
17#include <linux/sunrpc/msg_prot.h>
18
19/*
20 * XDR functions for basic NFS types
21 */
d8ed029d
AD
22__be32 *
23xdr_encode_netobj(__be32 *p, const struct xdr_netobj *obj)
1da177e4
LT
24{
25 unsigned int quadlen = XDR_QUADLEN(obj->len);
26
27 p[quadlen] = 0; /* zero trailing bytes */
9f162d2a 28 *p++ = cpu_to_be32(obj->len);
1da177e4
LT
29 memcpy(p, obj->data, obj->len);
30 return p + XDR_QUADLEN(obj->len);
31}
468039ee 32EXPORT_SYMBOL_GPL(xdr_encode_netobj);
1da177e4 33
d8ed029d
AD
34__be32 *
35xdr_decode_netobj(__be32 *p, struct xdr_netobj *obj)
1da177e4
LT
36{
37 unsigned int len;
38
98866b5a 39 if ((len = be32_to_cpu(*p++)) > XDR_MAX_NETOBJ)
1da177e4
LT
40 return NULL;
41 obj->len = len;
42 obj->data = (u8 *) p;
43 return p + XDR_QUADLEN(len);
44}
468039ee 45EXPORT_SYMBOL_GPL(xdr_decode_netobj);
1da177e4
LT
46
47/**
48 * xdr_encode_opaque_fixed - Encode fixed length opaque data
4dc3b16b
PP
49 * @p: pointer to current position in XDR buffer.
50 * @ptr: pointer to data to encode (or NULL)
51 * @nbytes: size of data.
1da177e4
LT
52 *
53 * Copy the array of data of length nbytes at ptr to the XDR buffer
54 * at position p, then align to the next 32-bit boundary by padding
55 * with zero bytes (see RFC1832).
56 * Note: if ptr is NULL, only the padding is performed.
57 *
58 * Returns the updated current XDR buffer position
59 *
60 */
d8ed029d 61__be32 *xdr_encode_opaque_fixed(__be32 *p, const void *ptr, unsigned int nbytes)
1da177e4
LT
62{
63 if (likely(nbytes != 0)) {
64 unsigned int quadlen = XDR_QUADLEN(nbytes);
65 unsigned int padding = (quadlen << 2) - nbytes;
66
67 if (ptr != NULL)
68 memcpy(p, ptr, nbytes);
69 if (padding != 0)
70 memset((char *)p + nbytes, 0, padding);
71 p += quadlen;
72 }
73 return p;
74}
468039ee 75EXPORT_SYMBOL_GPL(xdr_encode_opaque_fixed);
1da177e4
LT
76
77/**
78 * xdr_encode_opaque - Encode variable length opaque data
4dc3b16b
PP
79 * @p: pointer to current position in XDR buffer.
80 * @ptr: pointer to data to encode (or NULL)
81 * @nbytes: size of data.
1da177e4
LT
82 *
83 * Returns the updated current XDR buffer position
84 */
d8ed029d 85__be32 *xdr_encode_opaque(__be32 *p, const void *ptr, unsigned int nbytes)
1da177e4 86{
9f162d2a 87 *p++ = cpu_to_be32(nbytes);
1da177e4
LT
88 return xdr_encode_opaque_fixed(p, ptr, nbytes);
89}
468039ee 90EXPORT_SYMBOL_GPL(xdr_encode_opaque);
1da177e4 91
d8ed029d
AD
92__be32 *
93xdr_encode_string(__be32 *p, const char *string)
1da177e4
LT
94{
95 return xdr_encode_array(p, string, strlen(string));
96}
468039ee 97EXPORT_SYMBOL_GPL(xdr_encode_string);
1da177e4 98
d8ed029d 99__be32 *
e5cff482
CL
100xdr_decode_string_inplace(__be32 *p, char **sp,
101 unsigned int *lenp, unsigned int maxlen)
1da177e4 102{
e5cff482 103 u32 len;
1da177e4 104
98866b5a 105 len = be32_to_cpu(*p++);
e5cff482 106 if (len > maxlen)
1da177e4
LT
107 return NULL;
108 *lenp = len;
109 *sp = (char *) p;
110 return p + XDR_QUADLEN(len);
111}
468039ee 112EXPORT_SYMBOL_GPL(xdr_decode_string_inplace);
1da177e4 113
b4687da7
CL
114/**
115 * xdr_terminate_string - '\0'-terminate a string residing in an xdr_buf
116 * @buf: XDR buffer where string resides
117 * @len: length of string, in bytes
118 *
119 */
120void
121xdr_terminate_string(struct xdr_buf *buf, const u32 len)
122{
123 char *kaddr;
124
b8541786 125 kaddr = kmap_atomic(buf->pages[0]);
b4687da7 126 kaddr[buf->page_base + len] = '\0';
b8541786 127 kunmap_atomic(kaddr);
b4687da7 128}
0d961aa9 129EXPORT_SYMBOL_GPL(xdr_terminate_string);
b4687da7 130
1da177e4
LT
131void
132xdr_inline_pages(struct xdr_buf *xdr, unsigned int offset,
133 struct page **pages, unsigned int base, unsigned int len)
134{
135 struct kvec *head = xdr->head;
136 struct kvec *tail = xdr->tail;
137 char *buf = (char *)head->iov_base;
138 unsigned int buflen = head->iov_len;
139
140 head->iov_len = offset;
141
142 xdr->pages = pages;
143 xdr->page_base = base;
144 xdr->page_len = len;
145
146 tail->iov_base = buf + offset;
147 tail->iov_len = buflen - offset;
148
149 xdr->buflen += len;
150}
468039ee 151EXPORT_SYMBOL_GPL(xdr_inline_pages);
1da177e4 152
1da177e4
LT
153/*
154 * Helper routines for doing 'memmove' like operations on a struct xdr_buf
2c53040f
BH
155 */
156
157/**
1da177e4
LT
158 * _shift_data_right_pages
159 * @pages: vector of pages containing both the source and dest memory area.
160 * @pgto_base: page vector address of destination
161 * @pgfrom_base: page vector address of source
162 * @len: number of bytes to copy
163 *
164 * Note: the addresses pgto_base and pgfrom_base are both calculated in
165 * the same way:
166 * if a memory area starts at byte 'base' in page 'pages[i]',
ea1754a0 167 * then its address is given as (i << PAGE_SHIFT) + base
1da177e4
LT
168 * Also note: pgfrom_base must be < pgto_base, but the memory areas
169 * they point to may overlap.
170 */
171static void
172_shift_data_right_pages(struct page **pages, size_t pgto_base,
173 size_t pgfrom_base, size_t len)
174{
175 struct page **pgfrom, **pgto;
176 char *vfrom, *vto;
177 size_t copy;
178
179 BUG_ON(pgto_base <= pgfrom_base);
180
181 pgto_base += len;
182 pgfrom_base += len;
183
09cbfeaf
KS
184 pgto = pages + (pgto_base >> PAGE_SHIFT);
185 pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);
1da177e4 186
09cbfeaf
KS
187 pgto_base &= ~PAGE_MASK;
188 pgfrom_base &= ~PAGE_MASK;
1da177e4
LT
189
190 do {
191 /* Are any pointers crossing a page boundary? */
192 if (pgto_base == 0) {
09cbfeaf 193 pgto_base = PAGE_SIZE;
1da177e4
LT
194 pgto--;
195 }
196 if (pgfrom_base == 0) {
09cbfeaf 197 pgfrom_base = PAGE_SIZE;
1da177e4
LT
198 pgfrom--;
199 }
200
201 copy = len;
202 if (copy > pgto_base)
203 copy = pgto_base;
204 if (copy > pgfrom_base)
205 copy = pgfrom_base;
206 pgto_base -= copy;
207 pgfrom_base -= copy;
208
b8541786 209 vto = kmap_atomic(*pgto);
347e2233
TM
210 if (*pgto != *pgfrom) {
211 vfrom = kmap_atomic(*pgfrom);
212 memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);
213 kunmap_atomic(vfrom);
214 } else
215 memmove(vto + pgto_base, vto + pgfrom_base, copy);
bce3481c 216 flush_dcache_page(*pgto);
b8541786 217 kunmap_atomic(vto);
1da177e4
LT
218
219 } while ((len -= copy) != 0);
1da177e4
LT
220}
221
2c53040f 222/**
1da177e4
LT
223 * _copy_to_pages
224 * @pages: array of pages
225 * @pgbase: page vector address of destination
226 * @p: pointer to source data
227 * @len: length
228 *
229 * Copies data from an arbitrary memory location into an array of pages
230 * The copy is assumed to be non-overlapping.
231 */
232static void
233_copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len)
234{
235 struct page **pgto;
236 char *vto;
237 size_t copy;
238
09cbfeaf
KS
239 pgto = pages + (pgbase >> PAGE_SHIFT);
240 pgbase &= ~PAGE_MASK;
1da177e4 241
daeba89d 242 for (;;) {
09cbfeaf 243 copy = PAGE_SIZE - pgbase;
1da177e4
LT
244 if (copy > len)
245 copy = len;
246
b8541786 247 vto = kmap_atomic(*pgto);
1da177e4 248 memcpy(vto + pgbase, p, copy);
b8541786 249 kunmap_atomic(vto);
1da177e4 250
daeba89d
TM
251 len -= copy;
252 if (len == 0)
253 break;
254
1da177e4 255 pgbase += copy;
09cbfeaf 256 if (pgbase == PAGE_SIZE) {
1da177e4
LT
257 flush_dcache_page(*pgto);
258 pgbase = 0;
259 pgto++;
260 }
261 p += copy;
daeba89d 262 }
1da177e4
LT
263 flush_dcache_page(*pgto);
264}
265
2c53040f 266/**
1da177e4
LT
267 * _copy_from_pages
268 * @p: pointer to destination
269 * @pages: array of pages
270 * @pgbase: offset of source data
271 * @len: length
272 *
273 * Copies data into an arbitrary memory location from an array of pages
274 * The copy is assumed to be non-overlapping.
275 */
bf118a34 276void
1da177e4
LT
277_copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
278{
279 struct page **pgfrom;
280 char *vfrom;
281 size_t copy;
282
09cbfeaf
KS
283 pgfrom = pages + (pgbase >> PAGE_SHIFT);
284 pgbase &= ~PAGE_MASK;
1da177e4
LT
285
286 do {
09cbfeaf 287 copy = PAGE_SIZE - pgbase;
1da177e4
LT
288 if (copy > len)
289 copy = len;
290
b8541786 291 vfrom = kmap_atomic(*pgfrom);
1da177e4 292 memcpy(p, vfrom + pgbase, copy);
b8541786 293 kunmap_atomic(vfrom);
1da177e4
LT
294
295 pgbase += copy;
09cbfeaf 296 if (pgbase == PAGE_SIZE) {
1da177e4
LT
297 pgbase = 0;
298 pgfrom++;
299 }
300 p += copy;
301
302 } while ((len -= copy) != 0);
303}
bf118a34 304EXPORT_SYMBOL_GPL(_copy_from_pages);
1da177e4 305
2c53040f 306/**
1da177e4
LT
307 * xdr_shrink_bufhead
308 * @buf: xdr_buf
309 * @len: bytes to remove from buf->head[0]
310 *
cca5172a 311 * Shrinks XDR buffer's header kvec buf->head[0] by
1da177e4
LT
312 * 'len' bytes. The extra data is not lost, but is instead
313 * moved into the inlined pages and/or the tail.
314 */
315static void
316xdr_shrink_bufhead(struct xdr_buf *buf, size_t len)
317{
318 struct kvec *head, *tail;
319 size_t copy, offs;
320 unsigned int pglen = buf->page_len;
321
322 tail = buf->tail;
323 head = buf->head;
18e624ad
WAA
324
325 WARN_ON_ONCE(len > head->iov_len);
326 if (len > head->iov_len)
327 len = head->iov_len;
1da177e4
LT
328
329 /* Shift the tail first */
330 if (tail->iov_len != 0) {
331 if (tail->iov_len > len) {
332 copy = tail->iov_len - len;
333 memmove((char *)tail->iov_base + len,
334 tail->iov_base, copy);
335 }
336 /* Copy from the inlined pages into the tail */
337 copy = len;
338 if (copy > pglen)
339 copy = pglen;
340 offs = len - copy;
341 if (offs >= tail->iov_len)
342 copy = 0;
343 else if (copy > tail->iov_len - offs)
344 copy = tail->iov_len - offs;
345 if (copy != 0)
346 _copy_from_pages((char *)tail->iov_base + offs,
347 buf->pages,
348 buf->page_base + pglen + offs - len,
349 copy);
350 /* Do we also need to copy data from the head into the tail ? */
351 if (len > pglen) {
352 offs = copy = len - pglen;
353 if (copy > tail->iov_len)
354 copy = tail->iov_len;
355 memcpy(tail->iov_base,
356 (char *)head->iov_base +
357 head->iov_len - offs,
358 copy);
359 }
360 }
361 /* Now handle pages */
362 if (pglen != 0) {
363 if (pglen > len)
364 _shift_data_right_pages(buf->pages,
365 buf->page_base + len,
366 buf->page_base,
367 pglen - len);
368 copy = len;
369 if (len > pglen)
370 copy = pglen;
371 _copy_to_pages(buf->pages, buf->page_base,
372 (char *)head->iov_base + head->iov_len - len,
373 copy);
374 }
375 head->iov_len -= len;
376 buf->buflen -= len;
377 /* Have we truncated the message? */
378 if (buf->len > buf->buflen)
379 buf->len = buf->buflen;
380}
381
2c53040f 382/**
1da177e4
LT
383 * xdr_shrink_pagelen
384 * @buf: xdr_buf
385 * @len: bytes to remove from buf->pages
386 *
cca5172a 387 * Shrinks XDR buffer's page array buf->pages by
1da177e4
LT
388 * 'len' bytes. The extra data is not lost, but is instead
389 * moved into the tail.
390 */
391static void
392xdr_shrink_pagelen(struct xdr_buf *buf, size_t len)
393{
394 struct kvec *tail;
395 size_t copy;
1da177e4 396 unsigned int pglen = buf->page_len;
cf187c2d 397 unsigned int tailbuf_len;
1da177e4
LT
398
399 tail = buf->tail;
400 BUG_ON (len > pglen);
401
cf187c2d
TM
402 tailbuf_len = buf->buflen - buf->head->iov_len - buf->page_len;
403
1da177e4 404 /* Shift the tail first */
cf187c2d
TM
405 if (tailbuf_len != 0) {
406 unsigned int free_space = tailbuf_len - tail->iov_len;
407
408 if (len < free_space)
409 free_space = len;
410 tail->iov_len += free_space;
411
42d6d8ab 412 copy = len;
1da177e4 413 if (tail->iov_len > len) {
0fe62a35 414 char *p = (char *)tail->iov_base + len;
2e29ebb8 415 memmove(p, tail->iov_base, tail->iov_len - len);
42d6d8ab 416 } else
1da177e4 417 copy = tail->iov_len;
42d6d8ab 418 /* Copy from the inlined pages into the tail */
1da177e4
LT
419 _copy_from_pages((char *)tail->iov_base,
420 buf->pages, buf->page_base + pglen - len,
421 copy);
422 }
423 buf->page_len -= len;
424 buf->buflen -= len;
425 /* Have we truncated the message? */
426 if (buf->len > buf->buflen)
427 buf->len = buf->buflen;
428}
429
430void
431xdr_shift_buf(struct xdr_buf *buf, size_t len)
432{
433 xdr_shrink_bufhead(buf, len);
434}
468039ee 435EXPORT_SYMBOL_GPL(xdr_shift_buf);
1da177e4 436
4517d526
TM
437/**
438 * xdr_stream_pos - Return the current offset from the start of the xdr_stream
439 * @xdr: pointer to struct xdr_stream
440 */
441unsigned int xdr_stream_pos(const struct xdr_stream *xdr)
442{
443 return (unsigned int)(XDR_QUADLEN(xdr->buf->len) - xdr->nwords) << 2;
444}
445EXPORT_SYMBOL_GPL(xdr_stream_pos);
446
1da177e4
LT
447/**
448 * xdr_init_encode - Initialize a struct xdr_stream for sending data.
449 * @xdr: pointer to xdr_stream struct
450 * @buf: pointer to XDR buffer in which to encode data
451 * @p: current pointer inside XDR buffer
452 *
453 * Note: at the moment the RPC client only passes the length of our
454 * scratch buffer in the xdr_buf's header kvec. Previously this
455 * meant we needed to call xdr_adjust_iovec() after encoding the
456 * data. With the new scheme, the xdr_stream manages the details
457 * of the buffer length, and takes care of adjusting the kvec
458 * length for us.
459 */
d8ed029d 460void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
1da177e4
LT
461{
462 struct kvec *iov = buf->head;
334ccfd5 463 int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len;
1da177e4 464
2825a7f9 465 xdr_set_scratch_buffer(xdr, NULL, 0);
334ccfd5 466 BUG_ON(scratch_len < 0);
1da177e4
LT
467 xdr->buf = buf;
468 xdr->iov = iov;
d8ed029d
AD
469 xdr->p = (__be32 *)((char *)iov->iov_base + iov->iov_len);
470 xdr->end = (__be32 *)((char *)iov->iov_base + scratch_len);
334ccfd5
TM
471 BUG_ON(iov->iov_len > scratch_len);
472
473 if (p != xdr->p && p != NULL) {
474 size_t len;
475
476 BUG_ON(p < xdr->p || p > xdr->end);
477 len = (char *)p - (char *)xdr->p;
478 xdr->p = p;
479 buf->len += len;
480 iov->iov_len += len;
481 }
1da177e4 482}
468039ee 483EXPORT_SYMBOL_GPL(xdr_init_encode);
1da177e4 484
2825a7f9
BF
485/**
486 * xdr_commit_encode - Ensure all data is written to buffer
487 * @xdr: pointer to xdr_stream
488 *
489 * We handle encoding across page boundaries by giving the caller a
490 * temporary location to write to, then later copying the data into
491 * place; xdr_commit_encode does that copying.
492 *
493 * Normally the caller doesn't need to call this directly, as the
494 * following xdr_reserve_space will do it. But an explicit call may be
495 * required at the end of encoding, or any other time when the xdr_buf
496 * data might be read.
497 */
498void xdr_commit_encode(struct xdr_stream *xdr)
499{
500 int shift = xdr->scratch.iov_len;
501 void *page;
502
503 if (shift == 0)
504 return;
505 page = page_address(*xdr->page_ptr);
506 memcpy(xdr->scratch.iov_base, page, shift);
507 memmove(page, page + shift, (void *)xdr->p - page);
508 xdr->scratch.iov_len = 0;
509}
510EXPORT_SYMBOL_GPL(xdr_commit_encode);
511
22cb4385
TM
512static __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr,
513 size_t nbytes)
2825a7f9
BF
514{
515 static __be32 *p;
516 int space_left;
517 int frag1bytes, frag2bytes;
518
519 if (nbytes > PAGE_SIZE)
520 return NULL; /* Bigger buffers require special handling */
521 if (xdr->buf->len + nbytes > xdr->buf->buflen)
522 return NULL; /* Sorry, we're totally out of space */
523 frag1bytes = (xdr->end - xdr->p) << 2;
524 frag2bytes = nbytes - frag1bytes;
525 if (xdr->iov)
526 xdr->iov->iov_len += frag1bytes;
05638dc7 527 else
2825a7f9 528 xdr->buf->page_len += frag1bytes;
05638dc7 529 xdr->page_ptr++;
2825a7f9
BF
530 xdr->iov = NULL;
531 /*
532 * If the last encode didn't end exactly on a page boundary, the
533 * next one will straddle boundaries. Encode into the next
534 * page, then copy it back later in xdr_commit_encode. We use
535 * the "scratch" iov to track any temporarily unused fragment of
536 * space at the end of the previous buffer:
537 */
538 xdr->scratch.iov_base = xdr->p;
539 xdr->scratch.iov_len = frag1bytes;
540 p = page_address(*xdr->page_ptr);
541 /*
542 * Note this is where the next encode will start after we've
543 * shifted this one back:
544 */
545 xdr->p = (void *)p + frag2bytes;
546 space_left = xdr->buf->buflen - xdr->buf->len;
547 xdr->end = (void *)p + min_t(int, space_left, PAGE_SIZE);
548 xdr->buf->page_len += frag2bytes;
549 xdr->buf->len += nbytes;
550 return p;
551}
552
1da177e4
LT
553/**
554 * xdr_reserve_space - Reserve buffer space for sending
555 * @xdr: pointer to xdr_stream
556 * @nbytes: number of bytes to reserve
557 *
558 * Checks that we have enough buffer space to encode 'nbytes' more
559 * bytes of data. If so, update the total xdr_buf length, and
560 * adjust the length of the current kvec.
561 */
d8ed029d 562__be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
1da177e4 563{
d8ed029d
AD
564 __be32 *p = xdr->p;
565 __be32 *q;
1da177e4 566
2825a7f9 567 xdr_commit_encode(xdr);
1da177e4
LT
568 /* align nbytes on the next 32-bit boundary */
569 nbytes += 3;
570 nbytes &= ~3;
571 q = p + (nbytes >> 2);
572 if (unlikely(q > xdr->end || q < p))
2825a7f9 573 return xdr_get_next_encode_buffer(xdr, nbytes);
1da177e4 574 xdr->p = q;
2825a7f9
BF
575 if (xdr->iov)
576 xdr->iov->iov_len += nbytes;
577 else
578 xdr->buf->page_len += nbytes;
1da177e4
LT
579 xdr->buf->len += nbytes;
580 return p;
581}
468039ee 582EXPORT_SYMBOL_GPL(xdr_reserve_space);
1da177e4 583
3e19ce76
BF
584/**
585 * xdr_truncate_encode - truncate an encode buffer
586 * @xdr: pointer to xdr_stream
587 * @len: new length of buffer
588 *
589 * Truncates the xdr stream, so that xdr->buf->len == len,
590 * and xdr->p points at offset len from the start of the buffer, and
591 * head, tail, and page lengths are adjusted to correspond.
592 *
593 * If this means moving xdr->p to a different buffer, we assume that
594 * that the end pointer should be set to the end of the current page,
595 * except in the case of the head buffer when we assume the head
596 * buffer's current length represents the end of the available buffer.
597 *
598 * This is *not* safe to use on a buffer that already has inlined page
599 * cache pages (as in a zero-copy server read reply), except for the
600 * simple case of truncating from one position in the tail to another.
601 *
602 */
603void xdr_truncate_encode(struct xdr_stream *xdr, size_t len)
604{
605 struct xdr_buf *buf = xdr->buf;
606 struct kvec *head = buf->head;
607 struct kvec *tail = buf->tail;
608 int fraglen;
49a068f8 609 int new;
3e19ce76
BF
610
611 if (len > buf->len) {
612 WARN_ON_ONCE(1);
613 return;
614 }
2825a7f9 615 xdr_commit_encode(xdr);
3e19ce76
BF
616
617 fraglen = min_t(int, buf->len - len, tail->iov_len);
618 tail->iov_len -= fraglen;
619 buf->len -= fraglen;
ed38c069 620 if (tail->iov_len) {
3e19ce76 621 xdr->p = tail->iov_base + tail->iov_len;
280caac0
BF
622 WARN_ON_ONCE(!xdr->end);
623 WARN_ON_ONCE(!xdr->iov);
3e19ce76
BF
624 return;
625 }
626 WARN_ON_ONCE(fraglen);
627 fraglen = min_t(int, buf->len - len, buf->page_len);
628 buf->page_len -= fraglen;
629 buf->len -= fraglen;
630
631 new = buf->page_base + buf->page_len;
49a068f8
BF
632
633 xdr->page_ptr = buf->pages + (new >> PAGE_SHIFT);
3e19ce76 634
ed38c069 635 if (buf->page_len) {
3e19ce76
BF
636 xdr->p = page_address(*xdr->page_ptr);
637 xdr->end = (void *)xdr->p + PAGE_SIZE;
638 xdr->p = (void *)xdr->p + (new % PAGE_SIZE);
280caac0 639 WARN_ON_ONCE(xdr->iov);
3e19ce76
BF
640 return;
641 }
05638dc7 642 if (fraglen) {
3e19ce76 643 xdr->end = head->iov_base + head->iov_len;
05638dc7
BF
644 xdr->page_ptr--;
645 }
3e19ce76
BF
646 /* (otherwise assume xdr->end is already set) */
647 head->iov_len = len;
648 buf->len = len;
649 xdr->p = head->iov_base + head->iov_len;
650 xdr->iov = buf->head;
651}
652EXPORT_SYMBOL(xdr_truncate_encode);
653
db3f58a9
BF
654/**
655 * xdr_restrict_buflen - decrease available buffer space
656 * @xdr: pointer to xdr_stream
657 * @newbuflen: new maximum number of bytes available
658 *
659 * Adjust our idea of how much space is available in the buffer.
660 * If we've already used too much space in the buffer, returns -1.
661 * If the available space is already smaller than newbuflen, returns 0
662 * and does nothing. Otherwise, adjusts xdr->buf->buflen to newbuflen
663 * and ensures xdr->end is set at most offset newbuflen from the start
664 * of the buffer.
665 */
666int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen)
667{
668 struct xdr_buf *buf = xdr->buf;
669 int left_in_this_buf = (void *)xdr->end - (void *)xdr->p;
670 int end_offset = buf->len + left_in_this_buf;
671
672 if (newbuflen < 0 || newbuflen < buf->len)
673 return -1;
674 if (newbuflen > buf->buflen)
675 return 0;
676 if (newbuflen < end_offset)
677 xdr->end = (void *)xdr->end + newbuflen - end_offset;
678 buf->buflen = newbuflen;
679 return 0;
680}
681EXPORT_SYMBOL(xdr_restrict_buflen);
682
1da177e4
LT
683/**
684 * xdr_write_pages - Insert a list of pages into an XDR buffer for sending
685 * @xdr: pointer to xdr_stream
686 * @pages: list of pages
687 * @base: offset of first byte
688 * @len: length of data in bytes
689 *
690 */
691void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base,
692 unsigned int len)
693{
694 struct xdr_buf *buf = xdr->buf;
695 struct kvec *iov = buf->tail;
696 buf->pages = pages;
697 buf->page_base = base;
698 buf->page_len = len;
699
700 iov->iov_base = (char *)xdr->p;
701 iov->iov_len = 0;
702 xdr->iov = iov;
703
704 if (len & 3) {
705 unsigned int pad = 4 - (len & 3);
706
707 BUG_ON(xdr->p >= xdr->end);
708 iov->iov_base = (char *)xdr->p + (len & 3);
709 iov->iov_len += pad;
710 len += pad;
711 *xdr->p++ = 0;
712 }
713 buf->buflen += len;
714 buf->len += len;
715}
468039ee 716EXPORT_SYMBOL_GPL(xdr_write_pages);
1da177e4 717
6650239a 718static void xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
1537693c 719 unsigned int len)
6650239a
TM
720{
721 if (len > iov->iov_len)
722 len = iov->iov_len;
1537693c 723 xdr->p = (__be32*)iov->iov_base;
6650239a
TM
724 xdr->end = (__be32*)(iov->iov_base + len);
725 xdr->iov = iov;
726 xdr->page_ptr = NULL;
727}
728
729static int xdr_set_page_base(struct xdr_stream *xdr,
730 unsigned int base, unsigned int len)
731{
732 unsigned int pgnr;
733 unsigned int maxlen;
734 unsigned int pgoff;
735 unsigned int pgend;
736 void *kaddr;
737
738 maxlen = xdr->buf->page_len;
739 if (base >= maxlen)
740 return -EINVAL;
741 maxlen -= base;
742 if (len > maxlen)
743 len = maxlen;
744
745 base += xdr->buf->page_base;
746
747 pgnr = base >> PAGE_SHIFT;
748 xdr->page_ptr = &xdr->buf->pages[pgnr];
749 kaddr = page_address(*xdr->page_ptr);
750
751 pgoff = base & ~PAGE_MASK;
752 xdr->p = (__be32*)(kaddr + pgoff);
753
754 pgend = pgoff + len;
755 if (pgend > PAGE_SIZE)
756 pgend = PAGE_SIZE;
757 xdr->end = (__be32*)(kaddr + pgend);
758 xdr->iov = NULL;
759 return 0;
760}
761
762static void xdr_set_next_page(struct xdr_stream *xdr)
763{
764 unsigned int newbase;
765
766 newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT;
767 newbase -= xdr->buf->page_base;
768
769 if (xdr_set_page_base(xdr, newbase, PAGE_SIZE) < 0)
a6cebd41 770 xdr_set_iov(xdr, xdr->buf->tail, xdr->nwords << 2);
6650239a
TM
771}
772
773static bool xdr_set_next_buffer(struct xdr_stream *xdr)
774{
775 if (xdr->page_ptr != NULL)
776 xdr_set_next_page(xdr);
777 else if (xdr->iov == xdr->buf->head) {
778 if (xdr_set_page_base(xdr, 0, PAGE_SIZE) < 0)
a6cebd41 779 xdr_set_iov(xdr, xdr->buf->tail, xdr->nwords << 2);
6650239a
TM
780 }
781 return xdr->p != xdr->end;
782}
783
1da177e4
LT
784/**
785 * xdr_init_decode - Initialize an xdr_stream for decoding data.
786 * @xdr: pointer to xdr_stream struct
787 * @buf: pointer to XDR buffer from which to decode data
788 * @p: current pointer inside XDR buffer
789 */
d8ed029d 790void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
1da177e4 791{
1da177e4 792 xdr->buf = buf;
6650239a
TM
793 xdr->scratch.iov_base = NULL;
794 xdr->scratch.iov_len = 0;
bfeea1dc 795 xdr->nwords = XDR_QUADLEN(buf->len);
6650239a 796 if (buf->head[0].iov_len != 0)
1537693c 797 xdr_set_iov(xdr, buf->head, buf->len);
6650239a
TM
798 else if (buf->page_len != 0)
799 xdr_set_page_base(xdr, 0, buf->len);
06ef26a0
BC
800 else
801 xdr_set_iov(xdr, buf->head, buf->len);
bfeea1dc
TM
802 if (p != NULL && p > xdr->p && xdr->end >= p) {
803 xdr->nwords -= p - xdr->p;
1537693c 804 xdr->p = p;
bfeea1dc 805 }
1da177e4 806}
468039ee 807EXPORT_SYMBOL_GPL(xdr_init_decode);
1da177e4 808
f7da7a12
BH
809/**
810 * xdr_init_decode - Initialize an xdr_stream for decoding data.
811 * @xdr: pointer to xdr_stream struct
812 * @buf: pointer to XDR buffer from which to decode data
813 * @pages: list of pages to decode into
814 * @len: length in bytes of buffer in pages
815 */
816void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
817 struct page **pages, unsigned int len)
818{
819 memset(buf, 0, sizeof(*buf));
820 buf->pages = pages;
821 buf->page_len = len;
822 buf->buflen = len;
823 buf->len = len;
824 xdr_init_decode(xdr, buf, NULL);
825}
826EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
827
6650239a 828static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
ba8e452a 829{
bfeea1dc 830 unsigned int nwords = XDR_QUADLEN(nbytes);
ba8e452a 831 __be32 *p = xdr->p;
bfeea1dc 832 __be32 *q = p + nwords;
ba8e452a 833
bfeea1dc 834 if (unlikely(nwords > xdr->nwords || q > xdr->end || q < p))
ba8e452a 835 return NULL;
6650239a 836 xdr->p = q;
bfeea1dc 837 xdr->nwords -= nwords;
ba8e452a
TM
838 return p;
839}
ba8e452a 840
1da177e4 841/**
6650239a
TM
842 * xdr_set_scratch_buffer - Attach a scratch buffer for decoding data.
843 * @xdr: pointer to xdr_stream struct
844 * @buf: pointer to an empty buffer
845 * @buflen: size of 'buf'
846 *
847 * The scratch buffer is used when decoding from an array of pages.
848 * If an xdr_inline_decode() call spans across page boundaries, then
849 * we copy the data into the scratch buffer in order to allow linear
850 * access.
851 */
852void xdr_set_scratch_buffer(struct xdr_stream *xdr, void *buf, size_t buflen)
853{
854 xdr->scratch.iov_base = buf;
855 xdr->scratch.iov_len = buflen;
856}
857EXPORT_SYMBOL_GPL(xdr_set_scratch_buffer);
858
859static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes)
860{
861 __be32 *p;
ace0e14f 862 char *cpdest = xdr->scratch.iov_base;
6650239a
TM
863 size_t cplen = (char *)xdr->end - (char *)xdr->p;
864
865 if (nbytes > xdr->scratch.iov_len)
866 return NULL;
ace0e14f
TM
867 p = __xdr_inline_decode(xdr, cplen);
868 if (p == NULL)
869 return NULL;
870 memcpy(cpdest, p, cplen);
6650239a
TM
871 cpdest += cplen;
872 nbytes -= cplen;
873 if (!xdr_set_next_buffer(xdr))
874 return NULL;
875 p = __xdr_inline_decode(xdr, nbytes);
876 if (p == NULL)
877 return NULL;
878 memcpy(cpdest, p, nbytes);
879 return xdr->scratch.iov_base;
880}
881
882/**
883 * xdr_inline_decode - Retrieve XDR data to decode
1da177e4
LT
884 * @xdr: pointer to xdr_stream struct
885 * @nbytes: number of bytes of data to decode
886 *
887 * Check if the input buffer is long enough to enable us to decode
888 * 'nbytes' more bytes of data starting at the current position.
889 * If so return the current pointer, then update the current
890 * pointer position.
891 */
d8ed029d 892__be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
1da177e4 893{
6650239a 894 __be32 *p;
1da177e4 895
6650239a
TM
896 if (nbytes == 0)
897 return xdr->p;
898 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
1da177e4 899 return NULL;
6650239a
TM
900 p = __xdr_inline_decode(xdr, nbytes);
901 if (p != NULL)
902 return p;
903 return xdr_copy_to_scratch(xdr, nbytes);
1da177e4 904}
468039ee 905EXPORT_SYMBOL_GPL(xdr_inline_decode);
1da177e4 906
3994ee6f 907static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len)
1da177e4
LT
908{
909 struct xdr_buf *buf = xdr->buf;
910 struct kvec *iov;
bfeea1dc 911 unsigned int nwords = XDR_QUADLEN(len);
b760b313 912 unsigned int cur = xdr_stream_pos(xdr);
1da177e4 913
bfeea1dc 914 if (xdr->nwords == 0)
c337d365 915 return 0;
1da177e4
LT
916 /* Realign pages to current pointer position */
917 iov = buf->head;
a11a2bf4 918 if (iov->iov_len > cur) {
b760b313 919 xdr_shrink_bufhead(buf, iov->iov_len - cur);
a11a2bf4
TM
920 xdr->nwords = XDR_QUADLEN(buf->len - cur);
921 }
1da177e4 922
a11a2bf4
TM
923 if (nwords > xdr->nwords) {
924 nwords = xdr->nwords;
925 len = nwords << 2;
926 }
927 if (buf->page_len <= len)
8a9a8b83 928 len = buf->page_len;
a11a2bf4
TM
929 else if (nwords < xdr->nwords) {
930 /* Truncate page data and move it into the tail */
931 xdr_shrink_pagelen(buf, buf->page_len - len);
932 xdr->nwords = XDR_QUADLEN(buf->len - cur);
933 }
3994ee6f
TM
934 return len;
935}
bd00f84b 936
1da177e4
LT
937/**
938 * xdr_read_pages - Ensure page-based XDR data to decode is aligned at current pointer position
939 * @xdr: pointer to xdr_stream struct
940 * @len: number of bytes of page data
941 *
942 * Moves data beyond the current pointer position from the XDR head[] buffer
943 * into the page list. Any data that lies beyond current position + "len"
8b23ea7b 944 * bytes is moved into the XDR tail[].
3994ee6f
TM
945 *
946 * Returns the number of XDR encoded bytes now contained in the pages
1da177e4 947 */
3994ee6f 948unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
1da177e4
LT
949{
950 struct xdr_buf *buf = xdr->buf;
951 struct kvec *iov;
3994ee6f 952 unsigned int nwords;
1da177e4 953 unsigned int end;
3994ee6f 954 unsigned int padding;
1da177e4 955
3994ee6f
TM
956 len = xdr_align_pages(xdr, len);
957 if (len == 0)
958 return 0;
959 nwords = XDR_QUADLEN(len);
bfeea1dc 960 padding = (nwords << 2) - len;
1da177e4
LT
961 xdr->iov = iov = buf->tail;
962 /* Compute remaining message length. */
bd00f84b
TM
963 end = ((xdr->nwords - nwords) << 2) + padding;
964 if (end > iov->iov_len)
965 end = iov->iov_len;
966
1da177e4
LT
967 /*
968 * Position current pointer at beginning of tail, and
969 * set remaining message length.
970 */
d8ed029d
AD
971 xdr->p = (__be32 *)((char *)iov->iov_base + padding);
972 xdr->end = (__be32 *)((char *)iov->iov_base + end);
76cacaab 973 xdr->page_ptr = NULL;
bfeea1dc 974 xdr->nwords = XDR_QUADLEN(end - padding);
c337d365 975 return len;
1da177e4 976}
468039ee 977EXPORT_SYMBOL_GPL(xdr_read_pages);
1da177e4 978
8b23ea7b
TM
979/**
980 * xdr_enter_page - decode data from the XDR page
981 * @xdr: pointer to xdr_stream struct
982 * @len: number of bytes of page data
983 *
984 * Moves data beyond the current pointer position from the XDR head[] buffer
985 * into the page list. Any data that lies beyond current position + "len"
986 * bytes is moved into the XDR tail[]. The current pointer is then
987 * repositioned at the beginning of the first XDR page.
988 */
989void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
990{
f8bb7f08 991 len = xdr_align_pages(xdr, len);
8b23ea7b
TM
992 /*
993 * Position current pointer at beginning of tail, and
994 * set remaining message length.
995 */
f8bb7f08
TM
996 if (len != 0)
997 xdr_set_page_base(xdr, 0, len);
8b23ea7b 998}
468039ee 999EXPORT_SYMBOL_GPL(xdr_enter_page);
8b23ea7b 1000
1da177e4
LT
1001static struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0};
1002
1003void
1004xdr_buf_from_iov(struct kvec *iov, struct xdr_buf *buf)
1005{
1006 buf->head[0] = *iov;
1007 buf->tail[0] = empty_iov;
1008 buf->page_len = 0;
1009 buf->buflen = buf->len = iov->iov_len;
1010}
468039ee 1011EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
1da177e4 1012
de4aee2e
BF
1013/**
1014 * xdr_buf_subsegment - set subbuf to a portion of buf
1015 * @buf: an xdr buffer
1016 * @subbuf: the result buffer
1017 * @base: beginning of range in bytes
1018 * @len: length of range in bytes
1019 *
1020 * sets @subbuf to an xdr buffer representing the portion of @buf of
1021 * length @len starting at offset @base.
1022 *
1023 * @buf and @subbuf may be pointers to the same struct xdr_buf.
1024 *
1025 * Returns -1 if base of length are out of bounds.
1026 */
1da177e4
LT
1027int
1028xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
1e78957e 1029 unsigned int base, unsigned int len)
1da177e4 1030{
1da177e4 1031 subbuf->buflen = subbuf->len = len;
1e78957e
TM
1032 if (base < buf->head[0].iov_len) {
1033 subbuf->head[0].iov_base = buf->head[0].iov_base + base;
1034 subbuf->head[0].iov_len = min_t(unsigned int, len,
1035 buf->head[0].iov_len - base);
1036 len -= subbuf->head[0].iov_len;
1037 base = 0;
1038 } else {
1e78957e 1039 base -= buf->head[0].iov_len;
de4aee2e 1040 subbuf->head[0].iov_len = 0;
1e78957e 1041 }
1da177e4
LT
1042
1043 if (base < buf->page_len) {
1e78957e
TM
1044 subbuf->page_len = min(buf->page_len - base, len);
1045 base += buf->page_base;
09cbfeaf
KS
1046 subbuf->page_base = base & ~PAGE_MASK;
1047 subbuf->pages = &buf->pages[base >> PAGE_SHIFT];
1da177e4
LT
1048 len -= subbuf->page_len;
1049 base = 0;
1050 } else {
1051 base -= buf->page_len;
1052 subbuf->page_len = 0;
1053 }
1054
1e78957e
TM
1055 if (base < buf->tail[0].iov_len) {
1056 subbuf->tail[0].iov_base = buf->tail[0].iov_base + base;
1057 subbuf->tail[0].iov_len = min_t(unsigned int, len,
1058 buf->tail[0].iov_len - base);
1059 len -= subbuf->tail[0].iov_len;
1060 base = 0;
1061 } else {
1e78957e 1062 base -= buf->tail[0].iov_len;
de4aee2e 1063 subbuf->tail[0].iov_len = 0;
1e78957e
TM
1064 }
1065
1da177e4
LT
1066 if (base || len)
1067 return -1;
1068 return 0;
1069}
468039ee 1070EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
1da177e4 1071
4c190e2f
JL
1072/**
1073 * xdr_buf_trim - lop at most "len" bytes off the end of "buf"
1074 * @buf: buf to be trimmed
1075 * @len: number of bytes to reduce "buf" by
1076 *
1077 * Trim an xdr_buf by the given number of bytes by fixing up the lengths. Note
1078 * that it's possible that we'll trim less than that amount if the xdr_buf is
1079 * too small, or if (for instance) it's all in the head and the parser has
1080 * already read too far into it.
1081 */
1082void xdr_buf_trim(struct xdr_buf *buf, unsigned int len)
1083{
1084 size_t cur;
1085 unsigned int trim = len;
1086
1087 if (buf->tail[0].iov_len) {
1088 cur = min_t(size_t, buf->tail[0].iov_len, trim);
1089 buf->tail[0].iov_len -= cur;
1090 trim -= cur;
1091 if (!trim)
1092 goto fix_len;
1093 }
1094
1095 if (buf->page_len) {
1096 cur = min_t(unsigned int, buf->page_len, trim);
1097 buf->page_len -= cur;
1098 trim -= cur;
1099 if (!trim)
1100 goto fix_len;
1101 }
1102
1103 if (buf->head[0].iov_len) {
1104 cur = min_t(size_t, buf->head[0].iov_len, trim);
1105 buf->head[0].iov_len -= cur;
1106 trim -= cur;
1107 }
1108fix_len:
1109 buf->len -= (len - trim);
1110}
1111EXPORT_SYMBOL_GPL(xdr_buf_trim);
1112
4e3e43ad 1113static void __read_bytes_from_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
1da177e4 1114{
1e78957e 1115 unsigned int this_len;
1da177e4 1116
4e3e43ad
TM
1117 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1118 memcpy(obj, subbuf->head[0].iov_base, this_len);
1da177e4
LT
1119 len -= this_len;
1120 obj += this_len;
4e3e43ad 1121 this_len = min_t(unsigned int, len, subbuf->page_len);
1da177e4 1122 if (this_len)
4e3e43ad 1123 _copy_from_pages(obj, subbuf->pages, subbuf->page_base, this_len);
1da177e4
LT
1124 len -= this_len;
1125 obj += this_len;
4e3e43ad
TM
1126 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1127 memcpy(obj, subbuf->tail[0].iov_base, this_len);
1da177e4
LT
1128}
1129
bd8100e7 1130/* obj is assumed to point to allocated memory of size at least len: */
4e3e43ad 1131int read_bytes_from_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
bd8100e7
AG
1132{
1133 struct xdr_buf subbuf;
bd8100e7
AG
1134 int status;
1135
1136 status = xdr_buf_subsegment(buf, &subbuf, base, len);
4e3e43ad
TM
1137 if (status != 0)
1138 return status;
1139 __read_bytes_from_xdr_buf(&subbuf, obj, len);
1140 return 0;
1141}
468039ee 1142EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf);
4e3e43ad
TM
1143
1144static void __write_bytes_to_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
1145{
1146 unsigned int this_len;
1147
1148 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1149 memcpy(subbuf->head[0].iov_base, obj, this_len);
bd8100e7
AG
1150 len -= this_len;
1151 obj += this_len;
4e3e43ad 1152 this_len = min_t(unsigned int, len, subbuf->page_len);
bd8100e7 1153 if (this_len)
4e3e43ad 1154 _copy_to_pages(subbuf->pages, subbuf->page_base, obj, this_len);
bd8100e7
AG
1155 len -= this_len;
1156 obj += this_len;
4e3e43ad
TM
1157 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1158 memcpy(subbuf->tail[0].iov_base, obj, this_len);
1159}
1160
1161/* obj is assumed to point to allocated memory of size at least len: */
1162int write_bytes_to_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
1163{
1164 struct xdr_buf subbuf;
1165 int status;
1166
1167 status = xdr_buf_subsegment(buf, &subbuf, base, len);
1168 if (status != 0)
1169 return status;
1170 __write_bytes_to_xdr_buf(&subbuf, obj, len);
1171 return 0;
bd8100e7 1172}
c43abaed 1173EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf);
bd8100e7
AG
1174
1175int
1e78957e 1176xdr_decode_word(struct xdr_buf *buf, unsigned int base, u32 *obj)
1da177e4 1177{
d8ed029d 1178 __be32 raw;
1da177e4
LT
1179 int status;
1180
1181 status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
1182 if (status)
1183 return status;
98866b5a 1184 *obj = be32_to_cpu(raw);
1da177e4
LT
1185 return 0;
1186}
468039ee 1187EXPORT_SYMBOL_GPL(xdr_decode_word);
1da177e4 1188
bd8100e7 1189int
1e78957e 1190xdr_encode_word(struct xdr_buf *buf, unsigned int base, u32 obj)
bd8100e7 1191{
9f162d2a 1192 __be32 raw = cpu_to_be32(obj);
bd8100e7
AG
1193
1194 return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj));
1195}
468039ee 1196EXPORT_SYMBOL_GPL(xdr_encode_word);
bd8100e7 1197
1da177e4
LT
1198/* If the netobj starting offset bytes from the start of xdr_buf is contained
1199 * entirely in the head or the tail, set object to point to it; otherwise
1200 * try to find space for it at the end of the tail, copy it there, and
1201 * set obj to point to it. */
bee57c99 1202int xdr_buf_read_netobj(struct xdr_buf *buf, struct xdr_netobj *obj, unsigned int offset)
1da177e4 1203{
bee57c99 1204 struct xdr_buf subbuf;
1da177e4 1205
bd8100e7 1206 if (xdr_decode_word(buf, offset, &obj->len))
bee57c99
TM
1207 return -EFAULT;
1208 if (xdr_buf_subsegment(buf, &subbuf, offset + 4, obj->len))
1209 return -EFAULT;
1210
1211 /* Is the obj contained entirely in the head? */
1212 obj->data = subbuf.head[0].iov_base;
1213 if (subbuf.head[0].iov_len == obj->len)
1214 return 0;
1215 /* ..or is the obj contained entirely in the tail? */
1216 obj->data = subbuf.tail[0].iov_base;
1217 if (subbuf.tail[0].iov_len == obj->len)
1218 return 0;
1219
1220 /* use end of tail as storage for obj:
1221 * (We don't copy to the beginning because then we'd have
1222 * to worry about doing a potentially overlapping copy.
1223 * This assumes the object is at most half the length of the
1224 * tail.) */
1225 if (obj->len > buf->buflen - buf->len)
1226 return -ENOMEM;
1227 if (buf->tail[0].iov_len != 0)
1228 obj->data = buf->tail[0].iov_base + buf->tail[0].iov_len;
1229 else
1230 obj->data = buf->head[0].iov_base + buf->head[0].iov_len;
1231 __read_bytes_from_xdr_buf(&subbuf, obj->data, obj->len);
1da177e4 1232 return 0;
1da177e4 1233}
468039ee 1234EXPORT_SYMBOL_GPL(xdr_buf_read_netobj);
bd8100e7
AG
1235
1236/* Returns 0 on success, or else a negative error code. */
1237static int
1238xdr_xcode_array2(struct xdr_buf *buf, unsigned int base,
1239 struct xdr_array2_desc *desc, int encode)
1240{
1241 char *elem = NULL, *c;
1242 unsigned int copied = 0, todo, avail_here;
1243 struct page **ppages = NULL;
1244 int err;
1245
1246 if (encode) {
1247 if (xdr_encode_word(buf, base, desc->array_len) != 0)
1248 return -EINVAL;
1249 } else {
1250 if (xdr_decode_word(buf, base, &desc->array_len) != 0 ||
58fcb8df 1251 desc->array_len > desc->array_maxlen ||
bd8100e7
AG
1252 (unsigned long) base + 4 + desc->array_len *
1253 desc->elem_size > buf->len)
1254 return -EINVAL;
1255 }
1256 base += 4;
1257
1258 if (!desc->xcode)
1259 return 0;
1260
1261 todo = desc->array_len * desc->elem_size;
1262
1263 /* process head */
1264 if (todo && base < buf->head->iov_len) {
1265 c = buf->head->iov_base + base;
1266 avail_here = min_t(unsigned int, todo,
1267 buf->head->iov_len - base);
1268 todo -= avail_here;
1269
1270 while (avail_here >= desc->elem_size) {
1271 err = desc->xcode(desc, c);
1272 if (err)
1273 goto out;
1274 c += desc->elem_size;
1275 avail_here -= desc->elem_size;
1276 }
1277 if (avail_here) {
1278 if (!elem) {
1279 elem = kmalloc(desc->elem_size, GFP_KERNEL);
1280 err = -ENOMEM;
1281 if (!elem)
1282 goto out;
1283 }
1284 if (encode) {
1285 err = desc->xcode(desc, elem);
1286 if (err)
1287 goto out;
1288 memcpy(c, elem, avail_here);
1289 } else
1290 memcpy(elem, c, avail_here);
1291 copied = avail_here;
1292 }
1293 base = buf->head->iov_len; /* align to start of pages */
1294 }
1295
1296 /* process pages array */
1297 base -= buf->head->iov_len;
1298 if (todo && base < buf->page_len) {
1299 unsigned int avail_page;
1300
1301 avail_here = min(todo, buf->page_len - base);
1302 todo -= avail_here;
1303
1304 base += buf->page_base;
09cbfeaf
KS
1305 ppages = buf->pages + (base >> PAGE_SHIFT);
1306 base &= ~PAGE_MASK;
1307 avail_page = min_t(unsigned int, PAGE_SIZE - base,
bd8100e7
AG
1308 avail_here);
1309 c = kmap(*ppages) + base;
1310
1311 while (avail_here) {
1312 avail_here -= avail_page;
1313 if (copied || avail_page < desc->elem_size) {
1314 unsigned int l = min(avail_page,
1315 desc->elem_size - copied);
1316 if (!elem) {
1317 elem = kmalloc(desc->elem_size,
1318 GFP_KERNEL);
1319 err = -ENOMEM;
1320 if (!elem)
1321 goto out;
1322 }
1323 if (encode) {
1324 if (!copied) {
1325 err = desc->xcode(desc, elem);
1326 if (err)
1327 goto out;
1328 }
1329 memcpy(c, elem + copied, l);
1330 copied += l;
1331 if (copied == desc->elem_size)
1332 copied = 0;
1333 } else {
1334 memcpy(elem + copied, c, l);
1335 copied += l;
1336 if (copied == desc->elem_size) {
1337 err = desc->xcode(desc, elem);
1338 if (err)
1339 goto out;
1340 copied = 0;
1341 }
1342 }
1343 avail_page -= l;
1344 c += l;
1345 }
1346 while (avail_page >= desc->elem_size) {
1347 err = desc->xcode(desc, c);
1348 if (err)
1349 goto out;
1350 c += desc->elem_size;
1351 avail_page -= desc->elem_size;
1352 }
1353 if (avail_page) {
1354 unsigned int l = min(avail_page,
1355 desc->elem_size - copied);
1356 if (!elem) {
1357 elem = kmalloc(desc->elem_size,
1358 GFP_KERNEL);
1359 err = -ENOMEM;
1360 if (!elem)
1361 goto out;
1362 }
1363 if (encode) {
1364 if (!copied) {
1365 err = desc->xcode(desc, elem);
1366 if (err)
1367 goto out;
1368 }
1369 memcpy(c, elem + copied, l);
1370 copied += l;
1371 if (copied == desc->elem_size)
1372 copied = 0;
1373 } else {
1374 memcpy(elem + copied, c, l);
1375 copied += l;
1376 if (copied == desc->elem_size) {
1377 err = desc->xcode(desc, elem);
1378 if (err)
1379 goto out;
1380 copied = 0;
1381 }
1382 }
1383 }
1384 if (avail_here) {
1385 kunmap(*ppages);
1386 ppages++;
1387 c = kmap(*ppages);
1388 }
1389
1390 avail_page = min(avail_here,
09cbfeaf 1391 (unsigned int) PAGE_SIZE);
bd8100e7
AG
1392 }
1393 base = buf->page_len; /* align to start of tail */
1394 }
1395
1396 /* process tail */
1397 base -= buf->page_len;
1398 if (todo) {
1399 c = buf->tail->iov_base + base;
1400 if (copied) {
1401 unsigned int l = desc->elem_size - copied;
1402
1403 if (encode)
1404 memcpy(c, elem + copied, l);
1405 else {
1406 memcpy(elem + copied, c, l);
1407 err = desc->xcode(desc, elem);
1408 if (err)
1409 goto out;
1410 }
1411 todo -= l;
1412 c += l;
1413 }
1414 while (todo) {
1415 err = desc->xcode(desc, c);
1416 if (err)
1417 goto out;
1418 c += desc->elem_size;
1419 todo -= desc->elem_size;
1420 }
1421 }
1422 err = 0;
1423
1424out:
a51482bd 1425 kfree(elem);
bd8100e7
AG
1426 if (ppages)
1427 kunmap(*ppages);
1428 return err;
1429}
1430
1431int
1432xdr_decode_array2(struct xdr_buf *buf, unsigned int base,
1433 struct xdr_array2_desc *desc)
1434{
1435 if (base >= buf->len)
1436 return -EINVAL;
1437
1438 return xdr_xcode_array2(buf, base, desc, 0);
1439}
468039ee 1440EXPORT_SYMBOL_GPL(xdr_decode_array2);
bd8100e7
AG
1441
1442int
1443xdr_encode_array2(struct xdr_buf *buf, unsigned int base,
1444 struct xdr_array2_desc *desc)
1445{
1446 if ((unsigned long) base + 4 + desc->array_len * desc->elem_size >
1447 buf->head->iov_len + buf->page_len + buf->tail->iov_len)
1448 return -EINVAL;
1449
1450 return xdr_xcode_array2(buf, base, desc, 1);
1451}
468039ee 1452EXPORT_SYMBOL_GPL(xdr_encode_array2);
37a4e6cb
OK
1453
1454int
1455xdr_process_buf(struct xdr_buf *buf, unsigned int offset, unsigned int len,
cca5172a 1456 int (*actor)(struct scatterlist *, void *), void *data)
37a4e6cb
OK
1457{
1458 int i, ret = 0;
95c96174 1459 unsigned int page_len, thislen, page_offset;
37a4e6cb
OK
1460 struct scatterlist sg[1];
1461
68e3f5dd
HX
1462 sg_init_table(sg, 1);
1463
37a4e6cb
OK
1464 if (offset >= buf->head[0].iov_len) {
1465 offset -= buf->head[0].iov_len;
1466 } else {
1467 thislen = buf->head[0].iov_len - offset;
1468 if (thislen > len)
1469 thislen = len;
1470 sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
1471 ret = actor(sg, data);
1472 if (ret)
1473 goto out;
1474 offset = 0;
1475 len -= thislen;
1476 }
1477 if (len == 0)
1478 goto out;
1479
1480 if (offset >= buf->page_len) {
1481 offset -= buf->page_len;
1482 } else {
1483 page_len = buf->page_len - offset;
1484 if (page_len > len)
1485 page_len = len;
1486 len -= page_len;
09cbfeaf
KS
1487 page_offset = (offset + buf->page_base) & (PAGE_SIZE - 1);
1488 i = (offset + buf->page_base) >> PAGE_SHIFT;
1489 thislen = PAGE_SIZE - page_offset;
37a4e6cb
OK
1490 do {
1491 if (thislen > page_len)
1492 thislen = page_len;
642f1490 1493 sg_set_page(sg, buf->pages[i], thislen, page_offset);
37a4e6cb
OK
1494 ret = actor(sg, data);
1495 if (ret)
1496 goto out;
1497 page_len -= thislen;
1498 i++;
1499 page_offset = 0;
09cbfeaf 1500 thislen = PAGE_SIZE;
37a4e6cb
OK
1501 } while (page_len != 0);
1502 offset = 0;
1503 }
1504 if (len == 0)
1505 goto out;
1506 if (offset < buf->tail[0].iov_len) {
1507 thislen = buf->tail[0].iov_len - offset;
1508 if (thislen > len)
1509 thislen = len;
1510 sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
1511 ret = actor(sg, data);
1512 len -= thislen;
1513 }
1514 if (len != 0)
1515 ret = -EINVAL;
1516out:
1517 return ret;
1518}
468039ee 1519EXPORT_SYMBOL_GPL(xdr_process_buf);
37a4e6cb 1520