Commit | Line | Data |
---|---|---|
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 * |
23 | xdr_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 | 32 | EXPORT_SYMBOL_GPL(xdr_encode_netobj); |
1da177e4 | 33 | |
d8ed029d AD |
34 | __be32 * |
35 | xdr_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 | 45 | EXPORT_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 | 75 | EXPORT_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 | 90 | EXPORT_SYMBOL_GPL(xdr_encode_opaque); |
1da177e4 | 91 | |
d8ed029d AD |
92 | __be32 * |
93 | xdr_encode_string(__be32 *p, const char *string) | |
1da177e4 LT |
94 | { |
95 | return xdr_encode_array(p, string, strlen(string)); | |
96 | } | |
468039ee | 97 | EXPORT_SYMBOL_GPL(xdr_encode_string); |
1da177e4 | 98 | |
d8ed029d | 99 | __be32 * |
e5cff482 CL |
100 | xdr_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 | 112 | EXPORT_SYMBOL_GPL(xdr_decode_string_inplace); |
1da177e4 LT |
113 | |
114 | void | |
115 | xdr_encode_pages(struct xdr_buf *xdr, struct page **pages, unsigned int base, | |
116 | unsigned int len) | |
117 | { | |
118 | struct kvec *tail = xdr->tail; | |
119 | u32 *p; | |
120 | ||
121 | xdr->pages = pages; | |
122 | xdr->page_base = base; | |
123 | xdr->page_len = len; | |
124 | ||
125 | p = (u32 *)xdr->head[0].iov_base + XDR_QUADLEN(xdr->head[0].iov_len); | |
126 | tail->iov_base = p; | |
127 | tail->iov_len = 0; | |
128 | ||
129 | if (len & 3) { | |
130 | unsigned int pad = 4 - (len & 3); | |
131 | ||
132 | *p = 0; | |
133 | tail->iov_base = (char *)p + (len & 3); | |
134 | tail->iov_len = pad; | |
135 | len += pad; | |
136 | } | |
137 | xdr->buflen += len; | |
138 | xdr->len += len; | |
139 | } | |
468039ee | 140 | EXPORT_SYMBOL_GPL(xdr_encode_pages); |
1da177e4 LT |
141 | |
142 | void | |
143 | xdr_inline_pages(struct xdr_buf *xdr, unsigned int offset, | |
144 | struct page **pages, unsigned int base, unsigned int len) | |
145 | { | |
146 | struct kvec *head = xdr->head; | |
147 | struct kvec *tail = xdr->tail; | |
148 | char *buf = (char *)head->iov_base; | |
149 | unsigned int buflen = head->iov_len; | |
150 | ||
151 | head->iov_len = offset; | |
152 | ||
153 | xdr->pages = pages; | |
154 | xdr->page_base = base; | |
155 | xdr->page_len = len; | |
156 | ||
157 | tail->iov_base = buf + offset; | |
158 | tail->iov_len = buflen - offset; | |
159 | ||
160 | xdr->buflen += len; | |
161 | } | |
468039ee | 162 | EXPORT_SYMBOL_GPL(xdr_inline_pages); |
1da177e4 | 163 | |
1da177e4 LT |
164 | /* |
165 | * Helper routines for doing 'memmove' like operations on a struct xdr_buf | |
166 | * | |
167 | * _shift_data_right_pages | |
168 | * @pages: vector of pages containing both the source and dest memory area. | |
169 | * @pgto_base: page vector address of destination | |
170 | * @pgfrom_base: page vector address of source | |
171 | * @len: number of bytes to copy | |
172 | * | |
173 | * Note: the addresses pgto_base and pgfrom_base are both calculated in | |
174 | * the same way: | |
175 | * if a memory area starts at byte 'base' in page 'pages[i]', | |
176 | * then its address is given as (i << PAGE_CACHE_SHIFT) + base | |
177 | * Also note: pgfrom_base must be < pgto_base, but the memory areas | |
178 | * they point to may overlap. | |
179 | */ | |
180 | static void | |
181 | _shift_data_right_pages(struct page **pages, size_t pgto_base, | |
182 | size_t pgfrom_base, size_t len) | |
183 | { | |
184 | struct page **pgfrom, **pgto; | |
185 | char *vfrom, *vto; | |
186 | size_t copy; | |
187 | ||
188 | BUG_ON(pgto_base <= pgfrom_base); | |
189 | ||
190 | pgto_base += len; | |
191 | pgfrom_base += len; | |
192 | ||
193 | pgto = pages + (pgto_base >> PAGE_CACHE_SHIFT); | |
194 | pgfrom = pages + (pgfrom_base >> PAGE_CACHE_SHIFT); | |
195 | ||
196 | pgto_base &= ~PAGE_CACHE_MASK; | |
197 | pgfrom_base &= ~PAGE_CACHE_MASK; | |
198 | ||
199 | do { | |
200 | /* Are any pointers crossing a page boundary? */ | |
201 | if (pgto_base == 0) { | |
1da177e4 LT |
202 | pgto_base = PAGE_CACHE_SIZE; |
203 | pgto--; | |
204 | } | |
205 | if (pgfrom_base == 0) { | |
206 | pgfrom_base = PAGE_CACHE_SIZE; | |
207 | pgfrom--; | |
208 | } | |
209 | ||
210 | copy = len; | |
211 | if (copy > pgto_base) | |
212 | copy = pgto_base; | |
213 | if (copy > pgfrom_base) | |
214 | copy = pgfrom_base; | |
215 | pgto_base -= copy; | |
216 | pgfrom_base -= copy; | |
217 | ||
218 | vto = kmap_atomic(*pgto, KM_USER0); | |
219 | vfrom = kmap_atomic(*pgfrom, KM_USER1); | |
220 | memmove(vto + pgto_base, vfrom + pgfrom_base, copy); | |
bce3481c | 221 | flush_dcache_page(*pgto); |
1da177e4 LT |
222 | kunmap_atomic(vfrom, KM_USER1); |
223 | kunmap_atomic(vto, KM_USER0); | |
224 | ||
225 | } while ((len -= copy) != 0); | |
1da177e4 LT |
226 | } |
227 | ||
228 | /* | |
229 | * _copy_to_pages | |
230 | * @pages: array of pages | |
231 | * @pgbase: page vector address of destination | |
232 | * @p: pointer to source data | |
233 | * @len: length | |
234 | * | |
235 | * Copies data from an arbitrary memory location into an array of pages | |
236 | * The copy is assumed to be non-overlapping. | |
237 | */ | |
238 | static void | |
239 | _copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len) | |
240 | { | |
241 | struct page **pgto; | |
242 | char *vto; | |
243 | size_t copy; | |
244 | ||
245 | pgto = pages + (pgbase >> PAGE_CACHE_SHIFT); | |
246 | pgbase &= ~PAGE_CACHE_MASK; | |
247 | ||
daeba89d | 248 | for (;;) { |
1da177e4 LT |
249 | copy = PAGE_CACHE_SIZE - pgbase; |
250 | if (copy > len) | |
251 | copy = len; | |
252 | ||
253 | vto = kmap_atomic(*pgto, KM_USER0); | |
254 | memcpy(vto + pgbase, p, copy); | |
255 | kunmap_atomic(vto, KM_USER0); | |
256 | ||
daeba89d TM |
257 | len -= copy; |
258 | if (len == 0) | |
259 | break; | |
260 | ||
1da177e4 LT |
261 | pgbase += copy; |
262 | if (pgbase == PAGE_CACHE_SIZE) { | |
263 | flush_dcache_page(*pgto); | |
264 | pgbase = 0; | |
265 | pgto++; | |
266 | } | |
267 | p += copy; | |
daeba89d | 268 | } |
1da177e4 LT |
269 | flush_dcache_page(*pgto); |
270 | } | |
271 | ||
272 | /* | |
273 | * _copy_from_pages | |
274 | * @p: pointer to destination | |
275 | * @pages: array of pages | |
276 | * @pgbase: offset of source data | |
277 | * @len: length | |
278 | * | |
279 | * Copies data into an arbitrary memory location from an array of pages | |
280 | * The copy is assumed to be non-overlapping. | |
281 | */ | |
282 | static void | |
283 | _copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len) | |
284 | { | |
285 | struct page **pgfrom; | |
286 | char *vfrom; | |
287 | size_t copy; | |
288 | ||
289 | pgfrom = pages + (pgbase >> PAGE_CACHE_SHIFT); | |
290 | pgbase &= ~PAGE_CACHE_MASK; | |
291 | ||
292 | do { | |
293 | copy = PAGE_CACHE_SIZE - pgbase; | |
294 | if (copy > len) | |
295 | copy = len; | |
296 | ||
297 | vfrom = kmap_atomic(*pgfrom, KM_USER0); | |
298 | memcpy(p, vfrom + pgbase, copy); | |
299 | kunmap_atomic(vfrom, KM_USER0); | |
300 | ||
301 | pgbase += copy; | |
302 | if (pgbase == PAGE_CACHE_SIZE) { | |
303 | pgbase = 0; | |
304 | pgfrom++; | |
305 | } | |
306 | p += copy; | |
307 | ||
308 | } while ((len -= copy) != 0); | |
309 | } | |
310 | ||
311 | /* | |
312 | * xdr_shrink_bufhead | |
313 | * @buf: xdr_buf | |
314 | * @len: bytes to remove from buf->head[0] | |
315 | * | |
cca5172a | 316 | * Shrinks XDR buffer's header kvec buf->head[0] by |
1da177e4 LT |
317 | * 'len' bytes. The extra data is not lost, but is instead |
318 | * moved into the inlined pages and/or the tail. | |
319 | */ | |
320 | static void | |
321 | xdr_shrink_bufhead(struct xdr_buf *buf, size_t len) | |
322 | { | |
323 | struct kvec *head, *tail; | |
324 | size_t copy, offs; | |
325 | unsigned int pglen = buf->page_len; | |
326 | ||
327 | tail = buf->tail; | |
328 | head = buf->head; | |
329 | BUG_ON (len > head->iov_len); | |
330 | ||
331 | /* Shift the tail first */ | |
332 | if (tail->iov_len != 0) { | |
333 | if (tail->iov_len > len) { | |
334 | copy = tail->iov_len - len; | |
335 | memmove((char *)tail->iov_base + len, | |
336 | tail->iov_base, copy); | |
337 | } | |
338 | /* Copy from the inlined pages into the tail */ | |
339 | copy = len; | |
340 | if (copy > pglen) | |
341 | copy = pglen; | |
342 | offs = len - copy; | |
343 | if (offs >= tail->iov_len) | |
344 | copy = 0; | |
345 | else if (copy > tail->iov_len - offs) | |
346 | copy = tail->iov_len - offs; | |
347 | if (copy != 0) | |
348 | _copy_from_pages((char *)tail->iov_base + offs, | |
349 | buf->pages, | |
350 | buf->page_base + pglen + offs - len, | |
351 | copy); | |
352 | /* Do we also need to copy data from the head into the tail ? */ | |
353 | if (len > pglen) { | |
354 | offs = copy = len - pglen; | |
355 | if (copy > tail->iov_len) | |
356 | copy = tail->iov_len; | |
357 | memcpy(tail->iov_base, | |
358 | (char *)head->iov_base + | |
359 | head->iov_len - offs, | |
360 | copy); | |
361 | } | |
362 | } | |
363 | /* Now handle pages */ | |
364 | if (pglen != 0) { | |
365 | if (pglen > len) | |
366 | _shift_data_right_pages(buf->pages, | |
367 | buf->page_base + len, | |
368 | buf->page_base, | |
369 | pglen - len); | |
370 | copy = len; | |
371 | if (len > pglen) | |
372 | copy = pglen; | |
373 | _copy_to_pages(buf->pages, buf->page_base, | |
374 | (char *)head->iov_base + head->iov_len - len, | |
375 | copy); | |
376 | } | |
377 | head->iov_len -= len; | |
378 | buf->buflen -= len; | |
379 | /* Have we truncated the message? */ | |
380 | if (buf->len > buf->buflen) | |
381 | buf->len = buf->buflen; | |
382 | } | |
383 | ||
384 | /* | |
385 | * xdr_shrink_pagelen | |
386 | * @buf: xdr_buf | |
387 | * @len: bytes to remove from buf->pages | |
388 | * | |
cca5172a | 389 | * Shrinks XDR buffer's page array buf->pages by |
1da177e4 LT |
390 | * 'len' bytes. The extra data is not lost, but is instead |
391 | * moved into the tail. | |
392 | */ | |
393 | static void | |
394 | xdr_shrink_pagelen(struct xdr_buf *buf, size_t len) | |
395 | { | |
396 | struct kvec *tail; | |
397 | size_t copy; | |
1da177e4 LT |
398 | unsigned int pglen = buf->page_len; |
399 | ||
400 | tail = buf->tail; | |
401 | BUG_ON (len > pglen); | |
402 | ||
403 | /* Shift the tail first */ | |
404 | if (tail->iov_len != 0) { | |
42d6d8ab | 405 | copy = len; |
1da177e4 | 406 | if (tail->iov_len > len) { |
0fe62a35 | 407 | char *p = (char *)tail->iov_base + len; |
2e29ebb8 | 408 | memmove(p, tail->iov_base, tail->iov_len - len); |
42d6d8ab | 409 | } else |
1da177e4 | 410 | copy = tail->iov_len; |
42d6d8ab | 411 | /* Copy from the inlined pages into the tail */ |
1da177e4 LT |
412 | _copy_from_pages((char *)tail->iov_base, |
413 | buf->pages, buf->page_base + pglen - len, | |
414 | copy); | |
415 | } | |
416 | buf->page_len -= len; | |
417 | buf->buflen -= len; | |
418 | /* Have we truncated the message? */ | |
419 | if (buf->len > buf->buflen) | |
420 | buf->len = buf->buflen; | |
421 | } | |
422 | ||
423 | void | |
424 | xdr_shift_buf(struct xdr_buf *buf, size_t len) | |
425 | { | |
426 | xdr_shrink_bufhead(buf, len); | |
427 | } | |
468039ee | 428 | EXPORT_SYMBOL_GPL(xdr_shift_buf); |
1da177e4 LT |
429 | |
430 | /** | |
431 | * xdr_init_encode - Initialize a struct xdr_stream for sending data. | |
432 | * @xdr: pointer to xdr_stream struct | |
433 | * @buf: pointer to XDR buffer in which to encode data | |
434 | * @p: current pointer inside XDR buffer | |
435 | * | |
436 | * Note: at the moment the RPC client only passes the length of our | |
437 | * scratch buffer in the xdr_buf's header kvec. Previously this | |
438 | * meant we needed to call xdr_adjust_iovec() after encoding the | |
439 | * data. With the new scheme, the xdr_stream manages the details | |
440 | * of the buffer length, and takes care of adjusting the kvec | |
441 | * length for us. | |
442 | */ | |
d8ed029d | 443 | void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p) |
1da177e4 LT |
444 | { |
445 | struct kvec *iov = buf->head; | |
334ccfd5 | 446 | int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len; |
1da177e4 | 447 | |
334ccfd5 | 448 | BUG_ON(scratch_len < 0); |
1da177e4 LT |
449 | xdr->buf = buf; |
450 | xdr->iov = iov; | |
d8ed029d AD |
451 | xdr->p = (__be32 *)((char *)iov->iov_base + iov->iov_len); |
452 | xdr->end = (__be32 *)((char *)iov->iov_base + scratch_len); | |
334ccfd5 TM |
453 | BUG_ON(iov->iov_len > scratch_len); |
454 | ||
455 | if (p != xdr->p && p != NULL) { | |
456 | size_t len; | |
457 | ||
458 | BUG_ON(p < xdr->p || p > xdr->end); | |
459 | len = (char *)p - (char *)xdr->p; | |
460 | xdr->p = p; | |
461 | buf->len += len; | |
462 | iov->iov_len += len; | |
463 | } | |
1da177e4 | 464 | } |
468039ee | 465 | EXPORT_SYMBOL_GPL(xdr_init_encode); |
1da177e4 LT |
466 | |
467 | /** | |
468 | * xdr_reserve_space - Reserve buffer space for sending | |
469 | * @xdr: pointer to xdr_stream | |
470 | * @nbytes: number of bytes to reserve | |
471 | * | |
472 | * Checks that we have enough buffer space to encode 'nbytes' more | |
473 | * bytes of data. If so, update the total xdr_buf length, and | |
474 | * adjust the length of the current kvec. | |
475 | */ | |
d8ed029d | 476 | __be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes) |
1da177e4 | 477 | { |
d8ed029d AD |
478 | __be32 *p = xdr->p; |
479 | __be32 *q; | |
1da177e4 LT |
480 | |
481 | /* align nbytes on the next 32-bit boundary */ | |
482 | nbytes += 3; | |
483 | nbytes &= ~3; | |
484 | q = p + (nbytes >> 2); | |
485 | if (unlikely(q > xdr->end || q < p)) | |
486 | return NULL; | |
487 | xdr->p = q; | |
488 | xdr->iov->iov_len += nbytes; | |
489 | xdr->buf->len += nbytes; | |
490 | return p; | |
491 | } | |
468039ee | 492 | EXPORT_SYMBOL_GPL(xdr_reserve_space); |
1da177e4 LT |
493 | |
494 | /** | |
495 | * xdr_write_pages - Insert a list of pages into an XDR buffer for sending | |
496 | * @xdr: pointer to xdr_stream | |
497 | * @pages: list of pages | |
498 | * @base: offset of first byte | |
499 | * @len: length of data in bytes | |
500 | * | |
501 | */ | |
502 | void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base, | |
503 | unsigned int len) | |
504 | { | |
505 | struct xdr_buf *buf = xdr->buf; | |
506 | struct kvec *iov = buf->tail; | |
507 | buf->pages = pages; | |
508 | buf->page_base = base; | |
509 | buf->page_len = len; | |
510 | ||
511 | iov->iov_base = (char *)xdr->p; | |
512 | iov->iov_len = 0; | |
513 | xdr->iov = iov; | |
514 | ||
515 | if (len & 3) { | |
516 | unsigned int pad = 4 - (len & 3); | |
517 | ||
518 | BUG_ON(xdr->p >= xdr->end); | |
519 | iov->iov_base = (char *)xdr->p + (len & 3); | |
520 | iov->iov_len += pad; | |
521 | len += pad; | |
522 | *xdr->p++ = 0; | |
523 | } | |
524 | buf->buflen += len; | |
525 | buf->len += len; | |
526 | } | |
468039ee | 527 | EXPORT_SYMBOL_GPL(xdr_write_pages); |
1da177e4 LT |
528 | |
529 | /** | |
530 | * xdr_init_decode - Initialize an xdr_stream for decoding data. | |
531 | * @xdr: pointer to xdr_stream struct | |
532 | * @buf: pointer to XDR buffer from which to decode data | |
533 | * @p: current pointer inside XDR buffer | |
534 | */ | |
d8ed029d | 535 | void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p) |
1da177e4 LT |
536 | { |
537 | struct kvec *iov = buf->head; | |
538 | unsigned int len = iov->iov_len; | |
539 | ||
540 | if (len > buf->len) | |
541 | len = buf->len; | |
542 | xdr->buf = buf; | |
543 | xdr->iov = iov; | |
544 | xdr->p = p; | |
d8ed029d | 545 | xdr->end = (__be32 *)((char *)iov->iov_base + len); |
1da177e4 | 546 | } |
468039ee | 547 | EXPORT_SYMBOL_GPL(xdr_init_decode); |
1da177e4 LT |
548 | |
549 | /** | |
550 | * xdr_inline_decode - Retrieve non-page XDR data to decode | |
551 | * @xdr: pointer to xdr_stream struct | |
552 | * @nbytes: number of bytes of data to decode | |
553 | * | |
554 | * Check if the input buffer is long enough to enable us to decode | |
555 | * 'nbytes' more bytes of data starting at the current position. | |
556 | * If so return the current pointer, then update the current | |
557 | * pointer position. | |
558 | */ | |
d8ed029d | 559 | __be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes) |
1da177e4 | 560 | { |
d8ed029d AD |
561 | __be32 *p = xdr->p; |
562 | __be32 *q = p + XDR_QUADLEN(nbytes); | |
1da177e4 LT |
563 | |
564 | if (unlikely(q > xdr->end || q < p)) | |
565 | return NULL; | |
566 | xdr->p = q; | |
567 | return p; | |
568 | } | |
468039ee | 569 | EXPORT_SYMBOL_GPL(xdr_inline_decode); |
1da177e4 LT |
570 | |
571 | /** | |
572 | * xdr_read_pages - Ensure page-based XDR data to decode is aligned at current pointer position | |
573 | * @xdr: pointer to xdr_stream struct | |
574 | * @len: number of bytes of page data | |
575 | * | |
576 | * Moves data beyond the current pointer position from the XDR head[] buffer | |
577 | * into the page list. Any data that lies beyond current position + "len" | |
8b23ea7b | 578 | * bytes is moved into the XDR tail[]. |
1da177e4 LT |
579 | */ |
580 | void xdr_read_pages(struct xdr_stream *xdr, unsigned int len) | |
581 | { | |
582 | struct xdr_buf *buf = xdr->buf; | |
583 | struct kvec *iov; | |
584 | ssize_t shift; | |
585 | unsigned int end; | |
586 | int padding; | |
587 | ||
588 | /* Realign pages to current pointer position */ | |
589 | iov = buf->head; | |
590 | shift = iov->iov_len + (char *)iov->iov_base - (char *)xdr->p; | |
591 | if (shift > 0) | |
592 | xdr_shrink_bufhead(buf, shift); | |
593 | ||
594 | /* Truncate page data and move it into the tail */ | |
595 | if (buf->page_len > len) | |
596 | xdr_shrink_pagelen(buf, buf->page_len - len); | |
597 | padding = (XDR_QUADLEN(len) << 2) - len; | |
598 | xdr->iov = iov = buf->tail; | |
599 | /* Compute remaining message length. */ | |
600 | end = iov->iov_len; | |
601 | shift = buf->buflen - buf->len; | |
602 | if (shift < end) | |
603 | end -= shift; | |
604 | else if (shift > 0) | |
605 | end = 0; | |
606 | /* | |
607 | * Position current pointer at beginning of tail, and | |
608 | * set remaining message length. | |
609 | */ | |
d8ed029d AD |
610 | xdr->p = (__be32 *)((char *)iov->iov_base + padding); |
611 | xdr->end = (__be32 *)((char *)iov->iov_base + end); | |
1da177e4 | 612 | } |
468039ee | 613 | EXPORT_SYMBOL_GPL(xdr_read_pages); |
1da177e4 | 614 | |
8b23ea7b TM |
615 | /** |
616 | * xdr_enter_page - decode data from the XDR page | |
617 | * @xdr: pointer to xdr_stream struct | |
618 | * @len: number of bytes of page data | |
619 | * | |
620 | * Moves data beyond the current pointer position from the XDR head[] buffer | |
621 | * into the page list. Any data that lies beyond current position + "len" | |
622 | * bytes is moved into the XDR tail[]. The current pointer is then | |
623 | * repositioned at the beginning of the first XDR page. | |
624 | */ | |
625 | void xdr_enter_page(struct xdr_stream *xdr, unsigned int len) | |
626 | { | |
627 | char * kaddr = page_address(xdr->buf->pages[0]); | |
628 | xdr_read_pages(xdr, len); | |
629 | /* | |
630 | * Position current pointer at beginning of tail, and | |
631 | * set remaining message length. | |
632 | */ | |
633 | if (len > PAGE_CACHE_SIZE - xdr->buf->page_base) | |
634 | len = PAGE_CACHE_SIZE - xdr->buf->page_base; | |
d8ed029d AD |
635 | xdr->p = (__be32 *)(kaddr + xdr->buf->page_base); |
636 | xdr->end = (__be32 *)((char *)xdr->p + len); | |
8b23ea7b | 637 | } |
468039ee | 638 | EXPORT_SYMBOL_GPL(xdr_enter_page); |
8b23ea7b | 639 | |
1da177e4 LT |
640 | static struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0}; |
641 | ||
642 | void | |
643 | xdr_buf_from_iov(struct kvec *iov, struct xdr_buf *buf) | |
644 | { | |
645 | buf->head[0] = *iov; | |
646 | buf->tail[0] = empty_iov; | |
647 | buf->page_len = 0; | |
648 | buf->buflen = buf->len = iov->iov_len; | |
649 | } | |
468039ee | 650 | EXPORT_SYMBOL_GPL(xdr_buf_from_iov); |
1da177e4 | 651 | |
1da177e4 LT |
652 | /* Sets subbuf to the portion of buf of length len beginning base bytes |
653 | * from the start of buf. Returns -1 if base of length are out of bounds. */ | |
654 | int | |
655 | xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf, | |
1e78957e | 656 | unsigned int base, unsigned int len) |
1da177e4 | 657 | { |
1da177e4 | 658 | subbuf->buflen = subbuf->len = len; |
1e78957e TM |
659 | if (base < buf->head[0].iov_len) { |
660 | subbuf->head[0].iov_base = buf->head[0].iov_base + base; | |
661 | subbuf->head[0].iov_len = min_t(unsigned int, len, | |
662 | buf->head[0].iov_len - base); | |
663 | len -= subbuf->head[0].iov_len; | |
664 | base = 0; | |
665 | } else { | |
666 | subbuf->head[0].iov_base = NULL; | |
667 | subbuf->head[0].iov_len = 0; | |
668 | base -= buf->head[0].iov_len; | |
669 | } | |
1da177e4 LT |
670 | |
671 | if (base < buf->page_len) { | |
1e78957e TM |
672 | subbuf->page_len = min(buf->page_len - base, len); |
673 | base += buf->page_base; | |
674 | subbuf->page_base = base & ~PAGE_CACHE_MASK; | |
675 | subbuf->pages = &buf->pages[base >> PAGE_CACHE_SHIFT]; | |
1da177e4 LT |
676 | len -= subbuf->page_len; |
677 | base = 0; | |
678 | } else { | |
679 | base -= buf->page_len; | |
680 | subbuf->page_len = 0; | |
681 | } | |
682 | ||
1e78957e TM |
683 | if (base < buf->tail[0].iov_len) { |
684 | subbuf->tail[0].iov_base = buf->tail[0].iov_base + base; | |
685 | subbuf->tail[0].iov_len = min_t(unsigned int, len, | |
686 | buf->tail[0].iov_len - base); | |
687 | len -= subbuf->tail[0].iov_len; | |
688 | base = 0; | |
689 | } else { | |
690 | subbuf->tail[0].iov_base = NULL; | |
691 | subbuf->tail[0].iov_len = 0; | |
692 | base -= buf->tail[0].iov_len; | |
693 | } | |
694 | ||
1da177e4 LT |
695 | if (base || len) |
696 | return -1; | |
697 | return 0; | |
698 | } | |
468039ee | 699 | EXPORT_SYMBOL_GPL(xdr_buf_subsegment); |
1da177e4 | 700 | |
4e3e43ad | 701 | static void __read_bytes_from_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len) |
1da177e4 | 702 | { |
1e78957e | 703 | unsigned int this_len; |
1da177e4 | 704 | |
4e3e43ad TM |
705 | this_len = min_t(unsigned int, len, subbuf->head[0].iov_len); |
706 | memcpy(obj, subbuf->head[0].iov_base, this_len); | |
1da177e4 LT |
707 | len -= this_len; |
708 | obj += this_len; | |
4e3e43ad | 709 | this_len = min_t(unsigned int, len, subbuf->page_len); |
1da177e4 | 710 | if (this_len) |
4e3e43ad | 711 | _copy_from_pages(obj, subbuf->pages, subbuf->page_base, this_len); |
1da177e4 LT |
712 | len -= this_len; |
713 | obj += this_len; | |
4e3e43ad TM |
714 | this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len); |
715 | memcpy(obj, subbuf->tail[0].iov_base, this_len); | |
1da177e4 LT |
716 | } |
717 | ||
bd8100e7 | 718 | /* obj is assumed to point to allocated memory of size at least len: */ |
4e3e43ad | 719 | int read_bytes_from_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len) |
bd8100e7 AG |
720 | { |
721 | struct xdr_buf subbuf; | |
bd8100e7 AG |
722 | int status; |
723 | ||
724 | status = xdr_buf_subsegment(buf, &subbuf, base, len); | |
4e3e43ad TM |
725 | if (status != 0) |
726 | return status; | |
727 | __read_bytes_from_xdr_buf(&subbuf, obj, len); | |
728 | return 0; | |
729 | } | |
468039ee | 730 | EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf); |
4e3e43ad TM |
731 | |
732 | static void __write_bytes_to_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len) | |
733 | { | |
734 | unsigned int this_len; | |
735 | ||
736 | this_len = min_t(unsigned int, len, subbuf->head[0].iov_len); | |
737 | memcpy(subbuf->head[0].iov_base, obj, this_len); | |
bd8100e7 AG |
738 | len -= this_len; |
739 | obj += this_len; | |
4e3e43ad | 740 | this_len = min_t(unsigned int, len, subbuf->page_len); |
bd8100e7 | 741 | if (this_len) |
4e3e43ad | 742 | _copy_to_pages(subbuf->pages, subbuf->page_base, obj, this_len); |
bd8100e7 AG |
743 | len -= this_len; |
744 | obj += this_len; | |
4e3e43ad TM |
745 | this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len); |
746 | memcpy(subbuf->tail[0].iov_base, obj, this_len); | |
747 | } | |
748 | ||
749 | /* obj is assumed to point to allocated memory of size at least len: */ | |
750 | int write_bytes_to_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len) | |
751 | { | |
752 | struct xdr_buf subbuf; | |
753 | int status; | |
754 | ||
755 | status = xdr_buf_subsegment(buf, &subbuf, base, len); | |
756 | if (status != 0) | |
757 | return status; | |
758 | __write_bytes_to_xdr_buf(&subbuf, obj, len); | |
759 | return 0; | |
bd8100e7 | 760 | } |
c43abaed | 761 | EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf); |
bd8100e7 AG |
762 | |
763 | int | |
1e78957e | 764 | xdr_decode_word(struct xdr_buf *buf, unsigned int base, u32 *obj) |
1da177e4 | 765 | { |
d8ed029d | 766 | __be32 raw; |
1da177e4 LT |
767 | int status; |
768 | ||
769 | status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj)); | |
770 | if (status) | |
771 | return status; | |
98866b5a | 772 | *obj = be32_to_cpu(raw); |
1da177e4 LT |
773 | return 0; |
774 | } | |
468039ee | 775 | EXPORT_SYMBOL_GPL(xdr_decode_word); |
1da177e4 | 776 | |
bd8100e7 | 777 | int |
1e78957e | 778 | xdr_encode_word(struct xdr_buf *buf, unsigned int base, u32 obj) |
bd8100e7 | 779 | { |
9f162d2a | 780 | __be32 raw = cpu_to_be32(obj); |
bd8100e7 AG |
781 | |
782 | return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj)); | |
783 | } | |
468039ee | 784 | EXPORT_SYMBOL_GPL(xdr_encode_word); |
bd8100e7 | 785 | |
1da177e4 LT |
786 | /* If the netobj starting offset bytes from the start of xdr_buf is contained |
787 | * entirely in the head or the tail, set object to point to it; otherwise | |
788 | * try to find space for it at the end of the tail, copy it there, and | |
789 | * set obj to point to it. */ | |
bee57c99 | 790 | int xdr_buf_read_netobj(struct xdr_buf *buf, struct xdr_netobj *obj, unsigned int offset) |
1da177e4 | 791 | { |
bee57c99 | 792 | struct xdr_buf subbuf; |
1da177e4 | 793 | |
bd8100e7 | 794 | if (xdr_decode_word(buf, offset, &obj->len)) |
bee57c99 TM |
795 | return -EFAULT; |
796 | if (xdr_buf_subsegment(buf, &subbuf, offset + 4, obj->len)) | |
797 | return -EFAULT; | |
798 | ||
799 | /* Is the obj contained entirely in the head? */ | |
800 | obj->data = subbuf.head[0].iov_base; | |
801 | if (subbuf.head[0].iov_len == obj->len) | |
802 | return 0; | |
803 | /* ..or is the obj contained entirely in the tail? */ | |
804 | obj->data = subbuf.tail[0].iov_base; | |
805 | if (subbuf.tail[0].iov_len == obj->len) | |
806 | return 0; | |
807 | ||
808 | /* use end of tail as storage for obj: | |
809 | * (We don't copy to the beginning because then we'd have | |
810 | * to worry about doing a potentially overlapping copy. | |
811 | * This assumes the object is at most half the length of the | |
812 | * tail.) */ | |
813 | if (obj->len > buf->buflen - buf->len) | |
814 | return -ENOMEM; | |
815 | if (buf->tail[0].iov_len != 0) | |
816 | obj->data = buf->tail[0].iov_base + buf->tail[0].iov_len; | |
817 | else | |
818 | obj->data = buf->head[0].iov_base + buf->head[0].iov_len; | |
819 | __read_bytes_from_xdr_buf(&subbuf, obj->data, obj->len); | |
1da177e4 | 820 | return 0; |
1da177e4 | 821 | } |
468039ee | 822 | EXPORT_SYMBOL_GPL(xdr_buf_read_netobj); |
bd8100e7 AG |
823 | |
824 | /* Returns 0 on success, or else a negative error code. */ | |
825 | static int | |
826 | xdr_xcode_array2(struct xdr_buf *buf, unsigned int base, | |
827 | struct xdr_array2_desc *desc, int encode) | |
828 | { | |
829 | char *elem = NULL, *c; | |
830 | unsigned int copied = 0, todo, avail_here; | |
831 | struct page **ppages = NULL; | |
832 | int err; | |
833 | ||
834 | if (encode) { | |
835 | if (xdr_encode_word(buf, base, desc->array_len) != 0) | |
836 | return -EINVAL; | |
837 | } else { | |
838 | if (xdr_decode_word(buf, base, &desc->array_len) != 0 || | |
58fcb8df | 839 | desc->array_len > desc->array_maxlen || |
bd8100e7 AG |
840 | (unsigned long) base + 4 + desc->array_len * |
841 | desc->elem_size > buf->len) | |
842 | return -EINVAL; | |
843 | } | |
844 | base += 4; | |
845 | ||
846 | if (!desc->xcode) | |
847 | return 0; | |
848 | ||
849 | todo = desc->array_len * desc->elem_size; | |
850 | ||
851 | /* process head */ | |
852 | if (todo && base < buf->head->iov_len) { | |
853 | c = buf->head->iov_base + base; | |
854 | avail_here = min_t(unsigned int, todo, | |
855 | buf->head->iov_len - base); | |
856 | todo -= avail_here; | |
857 | ||
858 | while (avail_here >= desc->elem_size) { | |
859 | err = desc->xcode(desc, c); | |
860 | if (err) | |
861 | goto out; | |
862 | c += desc->elem_size; | |
863 | avail_here -= desc->elem_size; | |
864 | } | |
865 | if (avail_here) { | |
866 | if (!elem) { | |
867 | elem = kmalloc(desc->elem_size, GFP_KERNEL); | |
868 | err = -ENOMEM; | |
869 | if (!elem) | |
870 | goto out; | |
871 | } | |
872 | if (encode) { | |
873 | err = desc->xcode(desc, elem); | |
874 | if (err) | |
875 | goto out; | |
876 | memcpy(c, elem, avail_here); | |
877 | } else | |
878 | memcpy(elem, c, avail_here); | |
879 | copied = avail_here; | |
880 | } | |
881 | base = buf->head->iov_len; /* align to start of pages */ | |
882 | } | |
883 | ||
884 | /* process pages array */ | |
885 | base -= buf->head->iov_len; | |
886 | if (todo && base < buf->page_len) { | |
887 | unsigned int avail_page; | |
888 | ||
889 | avail_here = min(todo, buf->page_len - base); | |
890 | todo -= avail_here; | |
891 | ||
892 | base += buf->page_base; | |
893 | ppages = buf->pages + (base >> PAGE_CACHE_SHIFT); | |
894 | base &= ~PAGE_CACHE_MASK; | |
895 | avail_page = min_t(unsigned int, PAGE_CACHE_SIZE - base, | |
896 | avail_here); | |
897 | c = kmap(*ppages) + base; | |
898 | ||
899 | while (avail_here) { | |
900 | avail_here -= avail_page; | |
901 | if (copied || avail_page < desc->elem_size) { | |
902 | unsigned int l = min(avail_page, | |
903 | desc->elem_size - copied); | |
904 | if (!elem) { | |
905 | elem = kmalloc(desc->elem_size, | |
906 | GFP_KERNEL); | |
907 | err = -ENOMEM; | |
908 | if (!elem) | |
909 | goto out; | |
910 | } | |
911 | if (encode) { | |
912 | if (!copied) { | |
913 | err = desc->xcode(desc, elem); | |
914 | if (err) | |
915 | goto out; | |
916 | } | |
917 | memcpy(c, elem + copied, l); | |
918 | copied += l; | |
919 | if (copied == desc->elem_size) | |
920 | copied = 0; | |
921 | } else { | |
922 | memcpy(elem + copied, c, l); | |
923 | copied += l; | |
924 | if (copied == desc->elem_size) { | |
925 | err = desc->xcode(desc, elem); | |
926 | if (err) | |
927 | goto out; | |
928 | copied = 0; | |
929 | } | |
930 | } | |
931 | avail_page -= l; | |
932 | c += l; | |
933 | } | |
934 | while (avail_page >= desc->elem_size) { | |
935 | err = desc->xcode(desc, c); | |
936 | if (err) | |
937 | goto out; | |
938 | c += desc->elem_size; | |
939 | avail_page -= desc->elem_size; | |
940 | } | |
941 | if (avail_page) { | |
942 | unsigned int l = min(avail_page, | |
943 | desc->elem_size - copied); | |
944 | if (!elem) { | |
945 | elem = kmalloc(desc->elem_size, | |
946 | GFP_KERNEL); | |
947 | err = -ENOMEM; | |
948 | if (!elem) | |
949 | goto out; | |
950 | } | |
951 | if (encode) { | |
952 | if (!copied) { | |
953 | err = desc->xcode(desc, elem); | |
954 | if (err) | |
955 | goto out; | |
956 | } | |
957 | memcpy(c, elem + copied, l); | |
958 | copied += l; | |
959 | if (copied == desc->elem_size) | |
960 | copied = 0; | |
961 | } else { | |
962 | memcpy(elem + copied, c, l); | |
963 | copied += l; | |
964 | if (copied == desc->elem_size) { | |
965 | err = desc->xcode(desc, elem); | |
966 | if (err) | |
967 | goto out; | |
968 | copied = 0; | |
969 | } | |
970 | } | |
971 | } | |
972 | if (avail_here) { | |
973 | kunmap(*ppages); | |
974 | ppages++; | |
975 | c = kmap(*ppages); | |
976 | } | |
977 | ||
978 | avail_page = min(avail_here, | |
979 | (unsigned int) PAGE_CACHE_SIZE); | |
980 | } | |
981 | base = buf->page_len; /* align to start of tail */ | |
982 | } | |
983 | ||
984 | /* process tail */ | |
985 | base -= buf->page_len; | |
986 | if (todo) { | |
987 | c = buf->tail->iov_base + base; | |
988 | if (copied) { | |
989 | unsigned int l = desc->elem_size - copied; | |
990 | ||
991 | if (encode) | |
992 | memcpy(c, elem + copied, l); | |
993 | else { | |
994 | memcpy(elem + copied, c, l); | |
995 | err = desc->xcode(desc, elem); | |
996 | if (err) | |
997 | goto out; | |
998 | } | |
999 | todo -= l; | |
1000 | c += l; | |
1001 | } | |
1002 | while (todo) { | |
1003 | err = desc->xcode(desc, c); | |
1004 | if (err) | |
1005 | goto out; | |
1006 | c += desc->elem_size; | |
1007 | todo -= desc->elem_size; | |
1008 | } | |
1009 | } | |
1010 | err = 0; | |
1011 | ||
1012 | out: | |
a51482bd | 1013 | kfree(elem); |
bd8100e7 AG |
1014 | if (ppages) |
1015 | kunmap(*ppages); | |
1016 | return err; | |
1017 | } | |
1018 | ||
1019 | int | |
1020 | xdr_decode_array2(struct xdr_buf *buf, unsigned int base, | |
1021 | struct xdr_array2_desc *desc) | |
1022 | { | |
1023 | if (base >= buf->len) | |
1024 | return -EINVAL; | |
1025 | ||
1026 | return xdr_xcode_array2(buf, base, desc, 0); | |
1027 | } | |
468039ee | 1028 | EXPORT_SYMBOL_GPL(xdr_decode_array2); |
bd8100e7 AG |
1029 | |
1030 | int | |
1031 | xdr_encode_array2(struct xdr_buf *buf, unsigned int base, | |
1032 | struct xdr_array2_desc *desc) | |
1033 | { | |
1034 | if ((unsigned long) base + 4 + desc->array_len * desc->elem_size > | |
1035 | buf->head->iov_len + buf->page_len + buf->tail->iov_len) | |
1036 | return -EINVAL; | |
1037 | ||
1038 | return xdr_xcode_array2(buf, base, desc, 1); | |
1039 | } | |
468039ee | 1040 | EXPORT_SYMBOL_GPL(xdr_encode_array2); |
37a4e6cb OK |
1041 | |
1042 | int | |
1043 | xdr_process_buf(struct xdr_buf *buf, unsigned int offset, unsigned int len, | |
cca5172a | 1044 | int (*actor)(struct scatterlist *, void *), void *data) |
37a4e6cb OK |
1045 | { |
1046 | int i, ret = 0; | |
1047 | unsigned page_len, thislen, page_offset; | |
1048 | struct scatterlist sg[1]; | |
1049 | ||
68e3f5dd HX |
1050 | sg_init_table(sg, 1); |
1051 | ||
37a4e6cb OK |
1052 | if (offset >= buf->head[0].iov_len) { |
1053 | offset -= buf->head[0].iov_len; | |
1054 | } else { | |
1055 | thislen = buf->head[0].iov_len - offset; | |
1056 | if (thislen > len) | |
1057 | thislen = len; | |
1058 | sg_set_buf(sg, buf->head[0].iov_base + offset, thislen); | |
1059 | ret = actor(sg, data); | |
1060 | if (ret) | |
1061 | goto out; | |
1062 | offset = 0; | |
1063 | len -= thislen; | |
1064 | } | |
1065 | if (len == 0) | |
1066 | goto out; | |
1067 | ||
1068 | if (offset >= buf->page_len) { | |
1069 | offset -= buf->page_len; | |
1070 | } else { | |
1071 | page_len = buf->page_len - offset; | |
1072 | if (page_len > len) | |
1073 | page_len = len; | |
1074 | len -= page_len; | |
1075 | page_offset = (offset + buf->page_base) & (PAGE_CACHE_SIZE - 1); | |
1076 | i = (offset + buf->page_base) >> PAGE_CACHE_SHIFT; | |
1077 | thislen = PAGE_CACHE_SIZE - page_offset; | |
1078 | do { | |
1079 | if (thislen > page_len) | |
1080 | thislen = page_len; | |
642f1490 | 1081 | sg_set_page(sg, buf->pages[i], thislen, page_offset); |
37a4e6cb OK |
1082 | ret = actor(sg, data); |
1083 | if (ret) | |
1084 | goto out; | |
1085 | page_len -= thislen; | |
1086 | i++; | |
1087 | page_offset = 0; | |
1088 | thislen = PAGE_CACHE_SIZE; | |
1089 | } while (page_len != 0); | |
1090 | offset = 0; | |
1091 | } | |
1092 | if (len == 0) | |
1093 | goto out; | |
1094 | if (offset < buf->tail[0].iov_len) { | |
1095 | thislen = buf->tail[0].iov_len - offset; | |
1096 | if (thislen > len) | |
1097 | thislen = len; | |
1098 | sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen); | |
1099 | ret = actor(sg, data); | |
1100 | len -= thislen; | |
1101 | } | |
1102 | if (len != 0) | |
1103 | ret = -EINVAL; | |
1104 | out: | |
1105 | return ret; | |
1106 | } | |
468039ee | 1107 | EXPORT_SYMBOL_GPL(xdr_process_buf); |
37a4e6cb | 1108 |