1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * linux/net/sunrpc/xdr.c
4 *
5 * Generic XDR support.
6 *
7 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
8 */
9
10 #include <linux/module.h>
11 #include <linux/slab.h>
12 #include <linux/types.h>
13 #include <linux/string.h>
14 #include <linux/kernel.h>
15 #include <linux/pagemap.h>
16 #include <linux/errno.h>
17 #include <linux/sunrpc/xdr.h>
18 #include <linux/sunrpc/msg_prot.h>
19 #include <linux/bvec.h>
20 #include <trace/events/sunrpc.h>
21
22 static void _copy_to_pages(struct page **, size_t, const char *, size_t);
23
24
25 /*
26 * XDR functions for basic NFS types
27 */
28 __be32 *
29 xdr_encode_netobj(__be32 *p, const struct xdr_netobj *obj)
30 {
31 unsigned int quadlen = XDR_QUADLEN(obj->len);
32
33 p[quadlen] = 0; /* zero trailing bytes */
34 *p++ = cpu_to_be32(obj->len);
35 memcpy(p, obj->data, obj->len);
36 return p + XDR_QUADLEN(obj->len);
37 }
38 EXPORT_SYMBOL_GPL(xdr_encode_netobj);
39
40 __be32 *
41 xdr_decode_netobj(__be32 *p, struct xdr_netobj *obj)
42 {
43 unsigned int len;
44
45 if ((len = be32_to_cpu(*p++)) > XDR_MAX_NETOBJ)
46 return NULL;
47 obj->len = len;
48 obj->data = (u8 *) p;
49 return p + XDR_QUADLEN(len);
50 }
51 EXPORT_SYMBOL_GPL(xdr_decode_netobj);
52
53 /**
54 * xdr_encode_opaque_fixed - Encode fixed length opaque data
55 * @p: pointer to current position in XDR buffer.
56 * @ptr: pointer to data to encode (or NULL)
57 * @nbytes: size of data.
58 *
59 * Copy the array of data of length nbytes at ptr to the XDR buffer
60 * at position p, then align to the next 32-bit boundary by padding
61 * with zero bytes (see RFC1832).
62 * Note: if ptr is NULL, only the padding is performed.
63 *
64 * Returns the updated current XDR buffer position
65 *
66 */
67 __be32 *xdr_encode_opaque_fixed(__be32 *p, const void *ptr, unsigned int nbytes)
68 {
69 if (likely(nbytes != 0)) {
70 unsigned int quadlen = XDR_QUADLEN(nbytes);
71 unsigned int padding = (quadlen << 2) - nbytes;
72
73 if (ptr != NULL)
74 memcpy(p, ptr, nbytes);
75 if (padding != 0)
76 memset((char *)p + nbytes, 0, padding);
77 p += quadlen;
78 }
79 return p;
80 }
81 EXPORT_SYMBOL_GPL(xdr_encode_opaque_fixed);
82
83 /**
84 * xdr_encode_opaque - Encode variable length opaque data
85 * @p: pointer to current position in XDR buffer.
86 * @ptr: pointer to data to encode (or NULL)
87 * @nbytes: size of data.
88 *
89 * Returns the updated current XDR buffer position
90 */
91 __be32 *xdr_encode_opaque(__be32 *p, const void *ptr, unsigned int nbytes)
92 {
93 *p++ = cpu_to_be32(nbytes);
94 return xdr_encode_opaque_fixed(p, ptr, nbytes);
95 }
96 EXPORT_SYMBOL_GPL(xdr_encode_opaque);
97
98 __be32 *
99 xdr_encode_string(__be32 *p, const char *string)
100 {
101 return xdr_encode_array(p, string, strlen(string));
102 }
103 EXPORT_SYMBOL_GPL(xdr_encode_string);
104
105 __be32 *
106 xdr_decode_string_inplace(__be32 *p, char **sp,
107 unsigned int *lenp, unsigned int maxlen)
108 {
109 u32 len;
110
111 len = be32_to_cpu(*p++);
112 if (len > maxlen)
113 return NULL;
114 *lenp = len;
115 *sp = (char *) p;
116 return p + XDR_QUADLEN(len);
117 }
118 EXPORT_SYMBOL_GPL(xdr_decode_string_inplace);
119
120 /**
121 * xdr_terminate_string - '\0'-terminate a string residing in an xdr_buf
122 * @buf: XDR buffer where string resides
123 * @len: length of string, in bytes
124 *
125 */
126 void xdr_terminate_string(const struct xdr_buf *buf, const u32 len)
127 {
128 char *kaddr;
129
130 kaddr = kmap_atomic(buf->pages[0]);
131 kaddr[buf->page_base + len] = '\0';
132 kunmap_atomic(kaddr);
133 }
134 EXPORT_SYMBOL_GPL(xdr_terminate_string);
135
136 size_t xdr_buf_pagecount(const struct xdr_buf *buf)
137 {
138 if (!buf->page_len)
139 return 0;
140 return (buf->page_base + buf->page_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
141 }
142
143 int
144 xdr_alloc_bvec(struct xdr_buf *buf, gfp_t gfp)
145 {
146 size_t i, n = xdr_buf_pagecount(buf);
147
148 if (n != 0 && buf->bvec == NULL) {
149 buf->bvec = kmalloc_array(n, sizeof(buf->bvec[0]), gfp);
150 if (!buf->bvec)
151 return -ENOMEM;
152 for (i = 0; i < n; i++) {
153 buf->bvec[i].bv_page = buf->pages[i];
154 buf->bvec[i].bv_len = PAGE_SIZE;
155 buf->bvec[i].bv_offset = 0;
156 }
157 }
158 return 0;
159 }
160
161 void
162 xdr_free_bvec(struct xdr_buf *buf)
163 {
164 kfree(buf->bvec);
165 buf->bvec = NULL;
166 }
167
168 /**
169 * xdr_inline_pages - Prepare receive buffer for a large reply
170 * @xdr: xdr_buf into which reply will be placed
171 * @offset: expected offset where data payload will start, in bytes
172 * @pages: vector of struct page pointers
173 * @base: offset in first page where receive should start, in bytes
174 * @len: expected size of the upper layer data payload, in bytes
175 *
176 */
177 void
178 xdr_inline_pages(struct xdr_buf *xdr, unsigned int offset,
179 struct page **pages, unsigned int base, unsigned int len)
180 {
181 struct kvec *head = xdr->head;
182 struct kvec *tail = xdr->tail;
183 char *buf = (char *)head->iov_base;
184 unsigned int buflen = head->iov_len;
185
186 head->iov_len = offset;
187
188 xdr->pages = pages;
189 xdr->page_base = base;
190 xdr->page_len = len;
191
192 tail->iov_base = buf + offset;
193 tail->iov_len = buflen - offset;
194 xdr->buflen += len;
195 }
196 EXPORT_SYMBOL_GPL(xdr_inline_pages);
197
198 /*
199 * Helper routines for doing 'memmove' like operations on a struct xdr_buf
200 */
201
202 /**
203 * _shift_data_left_pages
204 * @pages: vector of pages containing both the source and dest memory area.
205 * @pgto_base: page vector address of destination
206 * @pgfrom_base: page vector address of source
207 * @len: number of bytes to copy
208 *
209 * Note: the addresses pgto_base and pgfrom_base are both calculated in
210 * the same way:
211 * if a memory area starts at byte 'base' in page 'pages[i]',
212 * then its address is given as (i << PAGE_CACHE_SHIFT) + base
213 * Alse note: pgto_base must be < pgfrom_base, but the memory areas
214 * they point to may overlap.
215 */
216 static void
217 _shift_data_left_pages(struct page **pages, size_t pgto_base,
218 size_t pgfrom_base, size_t len)
219 {
220 struct page **pgfrom, **pgto;
221 char *vfrom, *vto;
222 size_t copy;
223
224 BUG_ON(pgfrom_base <= pgto_base);
225
226 if (!len)
227 return;
228
229 pgto = pages + (pgto_base >> PAGE_SHIFT);
230 pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);
231
232 pgto_base &= ~PAGE_MASK;
233 pgfrom_base &= ~PAGE_MASK;
234
235 do {
236 if (pgto_base >= PAGE_SIZE) {
237 pgto_base = 0;
238 pgto++;
239 }
240 if (pgfrom_base >= PAGE_SIZE){
241 pgfrom_base = 0;
242 pgfrom++;
243 }
244
245 copy = len;
246 if (copy > (PAGE_SIZE - pgto_base))
247 copy = PAGE_SIZE - pgto_base;
248 if (copy > (PAGE_SIZE - pgfrom_base))
249 copy = PAGE_SIZE - pgfrom_base;
250
251 vto = kmap_atomic(*pgto);
252 if (*pgto != *pgfrom) {
253 vfrom = kmap_atomic(*pgfrom);
254 memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);
255 kunmap_atomic(vfrom);
256 } else
257 memmove(vto + pgto_base, vto + pgfrom_base, copy);
258 flush_dcache_page(*pgto);
259 kunmap_atomic(vto);
260
261 pgto_base += copy;
262 pgfrom_base += copy;
263
264 } while ((len -= copy) != 0);
265 }
266
267 /**
268 * _shift_data_right_pages
269 * @pages: vector of pages containing both the source and dest memory area.
270 * @pgto_base: page vector address of destination
271 * @pgfrom_base: page vector address of source
272 * @len: number of bytes to copy
273 *
274 * Note: the addresses pgto_base and pgfrom_base are both calculated in
275 * the same way:
276 * if a memory area starts at byte 'base' in page 'pages[i]',
277 * then its address is given as (i << PAGE_SHIFT) + base
278 * Also note: pgfrom_base must be < pgto_base, but the memory areas
279 * they point to may overlap.
280 */
281 static void
282 _shift_data_right_pages(struct page **pages, size_t pgto_base,
283 size_t pgfrom_base, size_t len)
284 {
285 struct page **pgfrom, **pgto;
286 char *vfrom, *vto;
287 size_t copy;
288
289 BUG_ON(pgto_base <= pgfrom_base);
290
291 if (!len)
292 return;
293
294 pgto_base += len;
295 pgfrom_base += len;
296
297 pgto = pages + (pgto_base >> PAGE_SHIFT);
298 pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);
299
300 pgto_base &= ~PAGE_MASK;
301 pgfrom_base &= ~PAGE_MASK;
302
303 do {
304 /* Are any pointers crossing a page boundary? */
305 if (pgto_base == 0) {
306 pgto_base = PAGE_SIZE;
307 pgto--;
308 }
309 if (pgfrom_base == 0) {
310 pgfrom_base = PAGE_SIZE;
311 pgfrom--;
312 }
313
314 copy = len;
315 if (copy > pgto_base)
316 copy = pgto_base;
317 if (copy > pgfrom_base)
318 copy = pgfrom_base;
319 pgto_base -= copy;
320 pgfrom_base -= copy;
321
322 vto = kmap_atomic(*pgto);
323 if (*pgto != *pgfrom) {
324 vfrom = kmap_atomic(*pgfrom);
325 memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);
326 kunmap_atomic(vfrom);
327 } else
328 memmove(vto + pgto_base, vto + pgfrom_base, copy);
329 flush_dcache_page(*pgto);
330 kunmap_atomic(vto);
331
332 } while ((len -= copy) != 0);
333 }
334
335 /**
336 * _copy_to_pages
337 * @pages: array of pages
338 * @pgbase: page vector address of destination
339 * @p: pointer to source data
340 * @len: length
341 *
342 * Copies data from an arbitrary memory location into an array of pages
343 * The copy is assumed to be non-overlapping.
344 */
345 static void
346 _copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len)
347 {
348 struct page **pgto;
349 char *vto;
350 size_t copy;
351
352 if (!len)
353 return;
354
355 pgto = pages + (pgbase >> PAGE_SHIFT);
356 pgbase &= ~PAGE_MASK;
357
358 for (;;) {
359 copy = PAGE_SIZE - pgbase;
360 if (copy > len)
361 copy = len;
362
363 vto = kmap_atomic(*pgto);
364 memcpy(vto + pgbase, p, copy);
365 kunmap_atomic(vto);
366
367 len -= copy;
368 if (len == 0)
369 break;
370
371 pgbase += copy;
372 if (pgbase == PAGE_SIZE) {
373 flush_dcache_page(*pgto);
374 pgbase = 0;
375 pgto++;
376 }
377 p += copy;
378 }
379 flush_dcache_page(*pgto);
380 }
381
382 /**
383 * _copy_from_pages
384 * @p: pointer to destination
385 * @pages: array of pages
386 * @pgbase: offset of source data
387 * @len: length
388 *
389 * Copies data into an arbitrary memory location from an array of pages
390 * The copy is assumed to be non-overlapping.
391 */
392 void
393 _copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
394 {
395 struct page **pgfrom;
396 char *vfrom;
397 size_t copy;
398
399 if (!len)
400 return;
401
402 pgfrom = pages + (pgbase >> PAGE_SHIFT);
403 pgbase &= ~PAGE_MASK;
404
405 do {
406 copy = PAGE_SIZE - pgbase;
407 if (copy > len)
408 copy = len;
409
410 vfrom = kmap_atomic(*pgfrom);
411 memcpy(p, vfrom + pgbase, copy);
412 kunmap_atomic(vfrom);
413
414 pgbase += copy;
415 if (pgbase == PAGE_SIZE) {
416 pgbase = 0;
417 pgfrom++;
418 }
419 p += copy;
420
421 } while ((len -= copy) != 0);
422 }
423 EXPORT_SYMBOL_GPL(_copy_from_pages);
424
425 static void xdr_buf_iov_zero(const struct kvec *iov, unsigned int base,
426 unsigned int len)
427 {
428 if (base >= iov->iov_len)
429 return;
430 if (len > iov->iov_len - base)
431 len = iov->iov_len - base;
432 memset(iov->iov_base + base, 0, len);
433 }
434
435 /**
436 * xdr_buf_pages_zero
437 * @buf: xdr_buf
438 * @pgbase: beginning offset
439 * @len: length
440 */
441 static void xdr_buf_pages_zero(const struct xdr_buf *buf, unsigned int pgbase,
442 unsigned int len)
443 {
444 struct page **pages = buf->pages;
445 struct page **page;
446 char *vpage;
447 unsigned int zero;
448
449 if (!len)
450 return;
451 if (pgbase >= buf->page_len) {
452 xdr_buf_iov_zero(buf->tail, pgbase - buf->page_len, len);
453 return;
454 }
455 if (pgbase + len > buf->page_len) {
456 xdr_buf_iov_zero(buf->tail, 0, pgbase + len - buf->page_len);
457 len = buf->page_len - pgbase;
458 }
459
460 pgbase += buf->page_base;
461
462 page = pages + (pgbase >> PAGE_SHIFT);
463 pgbase &= ~PAGE_MASK;
464
465 do {
466 zero = PAGE_SIZE - pgbase;
467 if (zero > len)
468 zero = len;
469
470 vpage = kmap_atomic(*page);
471 memset(vpage + pgbase, 0, zero);
472 kunmap_atomic(vpage);
473
474 flush_dcache_page(*page);
475 pgbase = 0;
476 page++;
477
478 } while ((len -= zero) != 0);
479 }
480
481 static unsigned int xdr_buf_pages_fill_sparse(const struct xdr_buf *buf,
482 unsigned int buflen, gfp_t gfp)
483 {
484 unsigned int i, npages, pagelen;
485
486 if (!(buf->flags & XDRBUF_SPARSE_PAGES))
487 return buflen;
488 if (buflen <= buf->head->iov_len)
489 return buflen;
490 pagelen = buflen - buf->head->iov_len;
491 if (pagelen > buf->page_len)
492 pagelen = buf->page_len;
493 npages = (pagelen + buf->page_base + PAGE_SIZE - 1) >> PAGE_SHIFT;
494 for (i = 0; i < npages; i++) {
495 if (!buf->pages[i])
496 continue;
497 buf->pages[i] = alloc_page(gfp);
498 if (likely(buf->pages[i]))
499 continue;
500 buflen -= pagelen;
501 pagelen = i << PAGE_SHIFT;
502 if (pagelen > buf->page_base)
503 buflen += pagelen - buf->page_base;
504 break;
505 }
506 return buflen;
507 }
508
509 static void xdr_buf_try_expand(struct xdr_buf *buf, unsigned int len)
510 {
511 struct kvec *head = buf->head;
512 struct kvec *tail = buf->tail;
513 unsigned int sum = head->iov_len + buf->page_len + tail->iov_len;
514 unsigned int free_space, newlen;
515
516 if (sum > buf->len) {
517 free_space = min_t(unsigned int, sum - buf->len, len);
518 newlen = xdr_buf_pages_fill_sparse(buf, buf->len + free_space,
519 GFP_KERNEL);
520 free_space = newlen - buf->len;
521 buf->len = newlen;
522 len -= free_space;
523 if (!len)
524 return;
525 }
526
527 if (buf->buflen > sum) {
528 /* Expand the tail buffer */
529 free_space = min_t(unsigned int, buf->buflen - sum, len);
530 tail->iov_len += free_space;
531 buf->len += free_space;
532 }
533 }
534
535 static void xdr_buf_tail_copy_right(const struct xdr_buf *buf,
536 unsigned int base, unsigned int len,
537 unsigned int shift)
538 {
539 const struct kvec *tail = buf->tail;
540 unsigned int to = base + shift;
541
542 if (to >= tail->iov_len)
543 return;
544 if (len + to > tail->iov_len)
545 len = tail->iov_len - to;
546 memmove(tail->iov_base + to, tail->iov_base + base, len);
547 }
548
549 static void xdr_buf_pages_copy_right(const struct xdr_buf *buf,
550 unsigned int base, unsigned int len,
551 unsigned int shift)
552 {
553 const struct kvec *tail = buf->tail;
554 unsigned int to = base + shift;
555 unsigned int pglen = 0;
556 unsigned int talen = 0, tato = 0;
557
558 if (base >= buf->page_len)
559 return;
560 if (len > buf->page_len - base)
561 len = buf->page_len - base;
562 if (to >= buf->page_len) {
563 tato = to - buf->page_len;
564 if (tail->iov_len >= len + tato)
565 talen = len;
566 else if (tail->iov_len > tato)
567 talen = tail->iov_len - tato;
568 } else if (len + to >= buf->page_len) {
569 pglen = buf->page_len - to;
570 talen = len - pglen;
571 if (talen > tail->iov_len)
572 talen = tail->iov_len;
573 } else
574 pglen = len;
575
576 _copy_from_pages(tail->iov_base + tato, buf->pages,
577 buf->page_base + base + pglen, talen);
578 _shift_data_right_pages(buf->pages, buf->page_base + to,
579 buf->page_base + base, pglen);
580 }
581
582 static void xdr_buf_head_copy_right(const struct xdr_buf *buf,
583 unsigned int base, unsigned int len,
584 unsigned int shift)
585 {
586 const struct kvec *head = buf->head;
587 const struct kvec *tail = buf->tail;
588 unsigned int to = base + shift;
589 unsigned int pglen = 0, pgto = 0;
590 unsigned int talen = 0, tato = 0;
591
592 if (base >= head->iov_len)
593 return;
594 if (len > head->iov_len - base)
595 len = head->iov_len - base;
596 if (to >= buf->page_len + head->iov_len) {
597 tato = to - buf->page_len - head->iov_len;
598 talen = len;
599 } else if (to >= head->iov_len) {
600 pgto = to - head->iov_len;
601 pglen = len;
602 if (pgto + pglen > buf->page_len) {
603 talen = pgto + pglen - buf->page_len;
604 pglen -= talen;
605 }
606 } else {
607 pglen = len - to;
608 if (pglen > buf->page_len) {
609 talen = pglen - buf->page_len;
610 pglen = buf->page_len;
611 }
612 }
613
614 len -= talen;
615 base += len;
616 if (talen + tato > tail->iov_len)
617 talen = tail->iov_len > tato ? tail->iov_len - tato : 0;
618 memcpy(tail->iov_base + tato, head->iov_base + base, talen);
619
620 len -= pglen;
621 base -= pglen;
622 _copy_to_pages(buf->pages, buf->page_base + pgto, head->iov_base + base,
623 pglen);
624
625 base -= len;
626 memmove(head->iov_base + to, head->iov_base + base, len);
627 }
628
629 static void xdr_buf_tail_shift_right(const struct xdr_buf *buf,
630 unsigned int base, unsigned int len,
631 unsigned int shift)
632 {
633 const struct kvec *tail = buf->tail;
634
635 if (base >= tail->iov_len || !shift || !len)
636 return;
637 xdr_buf_tail_copy_right(buf, base, len, shift);
638 }
639
640 static void xdr_buf_pages_shift_right(const struct xdr_buf *buf,
641 unsigned int base, unsigned int len,
642 unsigned int shift)
643 {
644 if (!shift || !len)
645 return;
646 if (base >= buf->page_len) {
647 xdr_buf_tail_shift_right(buf, base - buf->page_len, len, shift);
648 return;
649 }
650 if (base + len > buf->page_len)
651 xdr_buf_tail_shift_right(buf, 0, base + len - buf->page_len,
652 shift);
653 xdr_buf_pages_copy_right(buf, base, len, shift);
654 }
655
656 static void xdr_buf_head_shift_right(const struct xdr_buf *buf,
657 unsigned int base, unsigned int len,
658 unsigned int shift)
659 {
660 const struct kvec *head = buf->head;
661
662 if (!shift)
663 return;
664 if (base >= head->iov_len) {
665 xdr_buf_pages_shift_right(buf, head->iov_len - base, len,
666 shift);
667 return;
668 }
669 if (base + len > head->iov_len)
670 xdr_buf_pages_shift_right(buf, 0, base + len - head->iov_len,
671 shift);
672 xdr_buf_head_copy_right(buf, base, len, shift);
673 }
674
675 static void xdr_buf_tail_copy_left(const struct xdr_buf *buf, unsigned int base,
676 unsigned int len, unsigned int shift)
677 {
678 const struct kvec *tail = buf->tail;
679
680 if (base >= tail->iov_len)
681 return;
682 if (len > tail->iov_len - base)
683 len = tail->iov_len - base;
684 /* Shift data into head */
685 if (shift > buf->page_len + base) {
686 const struct kvec *head = buf->head;
687 unsigned int hdto =
688 head->iov_len + buf->page_len + base - shift;
689 unsigned int hdlen = len;
690
691 if (WARN_ONCE(shift > head->iov_len + buf->page_len + base,
692 "SUNRPC: Misaligned data.\n"))
693 return;
694 if (hdto + hdlen > head->iov_len)
695 hdlen = head->iov_len - hdto;
696 memcpy(head->iov_base + hdto, tail->iov_base + base, hdlen);
697 base += hdlen;
698 len -= hdlen;
699 if (!len)
700 return;
701 }
702 /* Shift data into pages */
703 if (shift > base) {
704 unsigned int pgto = buf->page_len + base - shift;
705 unsigned int pglen = len;
706
707 if (pgto + pglen > buf->page_len)
708 pglen = buf->page_len - pgto;
709 _copy_to_pages(buf->pages, buf->page_base + pgto,
710 tail->iov_base + base, pglen);
711 base += pglen;
712 len -= pglen;
713 if (!len)
714 return;
715 }
716 memmove(tail->iov_base + base - shift, tail->iov_base + base, len);
717 }
718
719 static void xdr_buf_pages_copy_left(const struct xdr_buf *buf,
720 unsigned int base, unsigned int len,
721 unsigned int shift)
722 {
723 unsigned int pgto;
724
725 if (base >= buf->page_len)
726 return;
727 if (len > buf->page_len - base)
728 len = buf->page_len - base;
729 /* Shift data into head */
730 if (shift > base) {
731 const struct kvec *head = buf->head;
732 unsigned int hdto = head->iov_len + base - shift;
733 unsigned int hdlen = len;
734
735 if (WARN_ONCE(shift > head->iov_len + base,
736 "SUNRPC: Misaligned data.\n"))
737 return;
738 if (hdto + hdlen > head->iov_len)
739 hdlen = head->iov_len - hdto;
740 _copy_from_pages(head->iov_base + hdto, buf->pages,
741 buf->page_base + base, hdlen);
742 base += hdlen;
743 len -= hdlen;
744 if (!len)
745 return;
746 }
747 pgto = base - shift;
748 _shift_data_left_pages(buf->pages, buf->page_base + pgto,
749 buf->page_base + base, len);
750 }
751
752 static void xdr_buf_tail_shift_left(const struct xdr_buf *buf,
753 unsigned int base, unsigned int len,
754 unsigned int shift)
755 {
756 if (!shift || !len)
757 return;
758 xdr_buf_tail_copy_left(buf, base, len, shift);
759 }
760
761 static void xdr_buf_pages_shift_left(const struct xdr_buf *buf,
762 unsigned int base, unsigned int len,
763 unsigned int shift)
764 {
765 if (!shift || !len)
766 return;
767 if (base >= buf->page_len) {
768 xdr_buf_tail_shift_left(buf, base - buf->page_len, len, shift);
769 return;
770 }
771 xdr_buf_pages_copy_left(buf, base, len, shift);
772 len += base;
773 if (len <= buf->page_len)
774 return;
775 xdr_buf_tail_copy_left(buf, 0, len - buf->page_len, shift);
776 }
777
778 /**
779 * xdr_shrink_bufhead
780 * @buf: xdr_buf
781 * @len: new length of buf->head[0]
782 *
783 * Shrinks XDR buffer's header kvec buf->head[0], setting it to
784 * 'len' bytes. The extra data is not lost, but is instead
785 * moved into the inlined pages and/or the tail.
786 */
787 static unsigned int xdr_shrink_bufhead(struct xdr_buf *buf, unsigned int len)
788 {
789 struct kvec *head = buf->head;
790 unsigned int shift, buflen = max(buf->len, len);
791
792 WARN_ON_ONCE(len > head->iov_len);
793 if (head->iov_len > buflen) {
794 buf->buflen -= head->iov_len - buflen;
795 head->iov_len = buflen;
796 }
797 if (len >= head->iov_len)
798 return 0;
799 shift = head->iov_len - len;
800 xdr_buf_try_expand(buf, shift);
801 xdr_buf_head_shift_right(buf, len, buflen - len, shift);
802 head->iov_len = len;
803 buf->buflen -= shift;
804 buf->len -= shift;
805 return shift;
806 }
807
808 /**
809 * xdr_shrink_pagelen - shrinks buf->pages to @len bytes
810 * @buf: xdr_buf
811 * @len: new page buffer length
812 *
813 * The extra data is not lost, but is instead moved into buf->tail.
814 * Returns the actual number of bytes moved.
815 */
816 static unsigned int xdr_shrink_pagelen(struct xdr_buf *buf, unsigned int len)
817 {
818 unsigned int shift, buflen = buf->len - buf->head->iov_len;
819
820 WARN_ON_ONCE(len > buf->page_len);
821 if (buf->head->iov_len >= buf->len || len > buflen)
822 buflen = len;
823 if (buf->page_len > buflen) {
824 buf->buflen -= buf->page_len - buflen;
825 buf->page_len = buflen;
826 }
827 if (len >= buf->page_len)
828 return 0;
829 shift = buf->page_len - len;
830 xdr_buf_try_expand(buf, shift);
831 xdr_buf_pages_shift_right(buf, len, buflen - len, shift);
832 buf->page_len = len;
833 buf->len -= shift;
834 buf->buflen -= shift;
835 return shift;
836 }
837
838 void
839 xdr_shift_buf(struct xdr_buf *buf, size_t len)
840 {
841 xdr_shrink_bufhead(buf, buf->head->iov_len - len);
842 }
843 EXPORT_SYMBOL_GPL(xdr_shift_buf);
844
845 /**
846 * xdr_stream_pos - Return the current offset from the start of the xdr_stream
847 * @xdr: pointer to struct xdr_stream
848 */
849 unsigned int xdr_stream_pos(const struct xdr_stream *xdr)
850 {
851 return (unsigned int)(XDR_QUADLEN(xdr->buf->len) - xdr->nwords) << 2;
852 }
853 EXPORT_SYMBOL_GPL(xdr_stream_pos);
854
855 static void xdr_stream_set_pos(struct xdr_stream *xdr, unsigned int pos)
856 {
857 unsigned int blen = xdr->buf->len;
858
859 xdr->nwords = blen > pos ? XDR_QUADLEN(blen) - XDR_QUADLEN(pos) : 0;
860 }
861
862 static void xdr_stream_page_set_pos(struct xdr_stream *xdr, unsigned int pos)
863 {
864 xdr_stream_set_pos(xdr, pos + xdr->buf->head[0].iov_len);
865 }
866
867 /**
868 * xdr_page_pos - Return the current offset from the start of the xdr pages
869 * @xdr: pointer to struct xdr_stream
870 */
871 unsigned int xdr_page_pos(const struct xdr_stream *xdr)
872 {
873 unsigned int pos = xdr_stream_pos(xdr);
874
875 WARN_ON(pos < xdr->buf->head[0].iov_len);
876 return pos - xdr->buf->head[0].iov_len;
877 }
878 EXPORT_SYMBOL_GPL(xdr_page_pos);
879
880 /**
881 * xdr_init_encode - Initialize a struct xdr_stream for sending data.
882 * @xdr: pointer to xdr_stream struct
883 * @buf: pointer to XDR buffer in which to encode data
884 * @p: current pointer inside XDR buffer
885 * @rqst: pointer to controlling rpc_rqst, for debugging
886 *
887 * Note: at the moment the RPC client only passes the length of our
888 * scratch buffer in the xdr_buf's header kvec. Previously this
889 * meant we needed to call xdr_adjust_iovec() after encoding the
890 * data. With the new scheme, the xdr_stream manages the details
891 * of the buffer length, and takes care of adjusting the kvec
892 * length for us.
893 */
894 void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
895 struct rpc_rqst *rqst)
896 {
897 struct kvec *iov = buf->head;
898 int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len;
899
900 xdr_reset_scratch_buffer(xdr);
901 BUG_ON(scratch_len < 0);
902 xdr->buf = buf;
903 xdr->iov = iov;
904 xdr->p = (__be32 *)((char *)iov->iov_base + iov->iov_len);
905 xdr->end = (__be32 *)((char *)iov->iov_base + scratch_len);
906 BUG_ON(iov->iov_len > scratch_len);
907
908 if (p != xdr->p && p != NULL) {
909 size_t len;
910
911 BUG_ON(p < xdr->p || p > xdr->end);
912 len = (char *)p - (char *)xdr->p;
913 xdr->p = p;
914 buf->len += len;
915 iov->iov_len += len;
916 }
917 xdr->rqst = rqst;
918 }
919 EXPORT_SYMBOL_GPL(xdr_init_encode);
920
921 /**
922 * xdr_commit_encode - Ensure all data is written to buffer
923 * @xdr: pointer to xdr_stream
924 *
925 * We handle encoding across page boundaries by giving the caller a
926 * temporary location to write to, then later copying the data into
927 * place; xdr_commit_encode does that copying.
928 *
929 * Normally the caller doesn't need to call this directly, as the
930 * following xdr_reserve_space will do it. But an explicit call may be
931 * required at the end of encoding, or any other time when the xdr_buf
932 * data might be read.
933 */
934 inline void xdr_commit_encode(struct xdr_stream *xdr)
935 {
936 int shift = xdr->scratch.iov_len;
937 void *page;
938
939 if (shift == 0)
940 return;
941 page = page_address(*xdr->page_ptr);
942 memcpy(xdr->scratch.iov_base, page, shift);
943 memmove(page, page + shift, (void *)xdr->p - page);
944 xdr_reset_scratch_buffer(xdr);
945 }
946 EXPORT_SYMBOL_GPL(xdr_commit_encode);
947
948 static __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr,
949 size_t nbytes)
950 {
951 __be32 *p;
952 int space_left;
953 int frag1bytes, frag2bytes;
954
955 if (nbytes > PAGE_SIZE)
956 goto out_overflow; /* Bigger buffers require special handling */
957 if (xdr->buf->len + nbytes > xdr->buf->buflen)
958 goto out_overflow; /* Sorry, we're totally out of space */
959 frag1bytes = (xdr->end - xdr->p) << 2;
960 frag2bytes = nbytes - frag1bytes;
961 if (xdr->iov)
962 xdr->iov->iov_len += frag1bytes;
963 else
964 xdr->buf->page_len += frag1bytes;
965 xdr->page_ptr++;
966 xdr->iov = NULL;
967 /*
968 * If the last encode didn't end exactly on a page boundary, the
969 * next one will straddle boundaries. Encode into the next
970 * page, then copy it back later in xdr_commit_encode. We use
971 * the "scratch" iov to track any temporarily unused fragment of
972 * space at the end of the previous buffer:
973 */
974 xdr_set_scratch_buffer(xdr, xdr->p, frag1bytes);
975 p = page_address(*xdr->page_ptr);
976 /*
977 * Note this is where the next encode will start after we've
978 * shifted this one back:
979 */
980 xdr->p = (void *)p + frag2bytes;
981 space_left = xdr->buf->buflen - xdr->buf->len;
982 if (space_left - frag1bytes >= PAGE_SIZE)
983 xdr->end = (void *)p + PAGE_SIZE;
984 else
985 xdr->end = (void *)p + space_left - frag1bytes;
986
987 xdr->buf->page_len += frag2bytes;
988 xdr->buf->len += nbytes;
989 return p;
990 out_overflow:
991 trace_rpc_xdr_overflow(xdr, nbytes);
992 return NULL;
993 }
994
995 /**
996 * xdr_reserve_space - Reserve buffer space for sending
997 * @xdr: pointer to xdr_stream
998 * @nbytes: number of bytes to reserve
999 *
1000 * Checks that we have enough buffer space to encode 'nbytes' more
1001 * bytes of data. If so, update the total xdr_buf length, and
1002 * adjust the length of the current kvec.
1003 */
1004 __be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
1005 {
1006 __be32 *p = xdr->p;
1007 __be32 *q;
1008
1009 xdr_commit_encode(xdr);
1010 /* align nbytes on the next 32-bit boundary */
1011 nbytes += 3;
1012 nbytes &= ~3;
1013 q = p + (nbytes >> 2);
1014 if (unlikely(q > xdr->end || q < p))
1015 return xdr_get_next_encode_buffer(xdr, nbytes);
1016 xdr->p = q;
1017 if (xdr->iov)
1018 xdr->iov->iov_len += nbytes;
1019 else
1020 xdr->buf->page_len += nbytes;
1021 xdr->buf->len += nbytes;
1022 return p;
1023 }
1024 EXPORT_SYMBOL_GPL(xdr_reserve_space);
1025
1026
1027 /**
1028 * xdr_reserve_space_vec - Reserves a large amount of buffer space for sending
1029 * @xdr: pointer to xdr_stream
1030 * @vec: pointer to a kvec array
1031 * @nbytes: number of bytes to reserve
1032 *
1033 * Reserves enough buffer space to encode 'nbytes' of data and stores the
1034 * pointers in 'vec'. The size argument passed to xdr_reserve_space() is
1035 * determined based on the number of bytes remaining in the current page to
1036 * avoid invalidating iov_base pointers when xdr_commit_encode() is called.
1037 */
1038 int xdr_reserve_space_vec(struct xdr_stream *xdr, struct kvec *vec, size_t nbytes)
1039 {
1040 int thislen;
1041 int v = 0;
1042 __be32 *p;
1043
1044 /*
1045 * svcrdma requires every READ payload to start somewhere
1046 * in xdr->pages.
1047 */
1048 if (xdr->iov == xdr->buf->head) {
1049 xdr->iov = NULL;
1050 xdr->end = xdr->p;
1051 }
1052
1053 while (nbytes) {
1054 thislen = xdr->buf->page_len % PAGE_SIZE;
1055 thislen = min_t(size_t, nbytes, PAGE_SIZE - thislen);
1056
1057 p = xdr_reserve_space(xdr, thislen);
1058 if (!p)
1059 return -EIO;
1060
1061 vec[v].iov_base = p;
1062 vec[v].iov_len = thislen;
1063 v++;
1064 nbytes -= thislen;
1065 }
1066
1067 return v;
1068 }
1069 EXPORT_SYMBOL_GPL(xdr_reserve_space_vec);
1070
1071 /**
1072 * xdr_truncate_encode - truncate an encode buffer
1073 * @xdr: pointer to xdr_stream
1074 * @len: new length of buffer
1075 *
1076 * Truncates the xdr stream, so that xdr->buf->len == len,
1077 * and xdr->p points at offset len from the start of the buffer, and
1078 * head, tail, and page lengths are adjusted to correspond.
1079 *
1080 * If this means moving xdr->p to a different buffer, we assume that
1081 * the end pointer should be set to the end of the current page,
1082 * except in the case of the head buffer when we assume the head
1083 * buffer's current length represents the end of the available buffer.
1084 *
1085 * This is *not* safe to use on a buffer that already has inlined page
1086 * cache pages (as in a zero-copy server read reply), except for the
1087 * simple case of truncating from one position in the tail to another.
1088 *
1089 */
1090 void xdr_truncate_encode(struct xdr_stream *xdr, size_t len)
1091 {
1092 struct xdr_buf *buf = xdr->buf;
1093 struct kvec *head = buf->head;
1094 struct kvec *tail = buf->tail;
1095 int fraglen;
1096 int new;
1097
1098 if (len > buf->len) {
1099 WARN_ON_ONCE(1);
1100 return;
1101 }
1102 xdr_commit_encode(xdr);
1103
1104 fraglen = min_t(int, buf->len - len, tail->iov_len);
1105 tail->iov_len -= fraglen;
1106 buf->len -= fraglen;
1107 if (tail->iov_len) {
1108 xdr->p = tail->iov_base + tail->iov_len;
1109 WARN_ON_ONCE(!xdr->end);
1110 WARN_ON_ONCE(!xdr->iov);
1111 return;
1112 }
1113 WARN_ON_ONCE(fraglen);
1114 fraglen = min_t(int, buf->len - len, buf->page_len);
1115 buf->page_len -= fraglen;
1116 buf->len -= fraglen;
1117
1118 new = buf->page_base + buf->page_len;
1119
1120 xdr->page_ptr = buf->pages + (new >> PAGE_SHIFT);
1121
1122 if (buf->page_len) {
1123 xdr->p = page_address(*xdr->page_ptr);
1124 xdr->end = (void *)xdr->p + PAGE_SIZE;
1125 xdr->p = (void *)xdr->p + (new % PAGE_SIZE);
1126 WARN_ON_ONCE(xdr->iov);
1127 return;
1128 }
1129 if (fraglen)
1130 xdr->end = head->iov_base + head->iov_len;
1131 /* (otherwise assume xdr->end is already set) */
1132 xdr->page_ptr--;
1133 head->iov_len = len;
1134 buf->len = len;
1135 xdr->p = head->iov_base + head->iov_len;
1136 xdr->iov = buf->head;
1137 }
1138 EXPORT_SYMBOL(xdr_truncate_encode);
1139
1140 /**
1141 * xdr_restrict_buflen - decrease available buffer space
1142 * @xdr: pointer to xdr_stream
1143 * @newbuflen: new maximum number of bytes available
1144 *
1145 * Adjust our idea of how much space is available in the buffer.
1146 * If we've already used too much space in the buffer, returns -1.
1147 * If the available space is already smaller than newbuflen, returns 0
1148 * and does nothing. Otherwise, adjusts xdr->buf->buflen to newbuflen
1149 * and ensures xdr->end is set at most offset newbuflen from the start
1150 * of the buffer.
1151 */
1152 int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen)
1153 {
1154 struct xdr_buf *buf = xdr->buf;
1155 int left_in_this_buf = (void *)xdr->end - (void *)xdr->p;
1156 int end_offset = buf->len + left_in_this_buf;
1157
1158 if (newbuflen < 0 || newbuflen < buf->len)
1159 return -1;
1160 if (newbuflen > buf->buflen)
1161 return 0;
1162 if (newbuflen < end_offset)
1163 xdr->end = (void *)xdr->end + newbuflen - end_offset;
1164 buf->buflen = newbuflen;
1165 return 0;
1166 }
1167 EXPORT_SYMBOL(xdr_restrict_buflen);
1168
1169 /**
1170 * xdr_write_pages - Insert a list of pages into an XDR buffer for sending
1171 * @xdr: pointer to xdr_stream
1172 * @pages: list of pages
1173 * @base: offset of first byte
1174 * @len: length of data in bytes
1175 *
1176 */
1177 void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base,
1178 unsigned int len)
1179 {
1180 struct xdr_buf *buf = xdr->buf;
1181 struct kvec *iov = buf->tail;
1182 buf->pages = pages;
1183 buf->page_base = base;
1184 buf->page_len = len;
1185
1186 iov->iov_base = (char *)xdr->p;
1187 iov->iov_len = 0;
1188 xdr->iov = iov;
1189
1190 if (len & 3) {
1191 unsigned int pad = 4 - (len & 3);
1192
1193 BUG_ON(xdr->p >= xdr->end);
1194 iov->iov_base = (char *)xdr->p + (len & 3);
1195 iov->iov_len += pad;
1196 len += pad;
1197 *xdr->p++ = 0;
1198 }
1199 buf->buflen += len;
1200 buf->len += len;
1201 }
1202 EXPORT_SYMBOL_GPL(xdr_write_pages);
1203
1204 static unsigned int xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
1205 unsigned int base, unsigned int len)
1206 {
1207 if (len > iov->iov_len)
1208 len = iov->iov_len;
1209 if (unlikely(base > len))
1210 base = len;
1211 xdr->p = (__be32*)(iov->iov_base + base);
1212 xdr->end = (__be32*)(iov->iov_base + len);
1213 xdr->iov = iov;
1214 xdr->page_ptr = NULL;
1215 return len - base;
1216 }
1217
1218 static unsigned int xdr_set_tail_base(struct xdr_stream *xdr,
1219 unsigned int base, unsigned int len)
1220 {
1221 struct xdr_buf *buf = xdr->buf;
1222
1223 xdr_stream_set_pos(xdr, base + buf->page_len + buf->head->iov_len);
1224 return xdr_set_iov(xdr, buf->tail, base, len);
1225 }
1226
1227 static unsigned int xdr_set_page_base(struct xdr_stream *xdr,
1228 unsigned int base, unsigned int len)
1229 {
1230 unsigned int pgnr;
1231 unsigned int maxlen;
1232 unsigned int pgoff;
1233 unsigned int pgend;
1234 void *kaddr;
1235
1236 maxlen = xdr->buf->page_len;
1237 if (base >= maxlen)
1238 return 0;
1239 else
1240 maxlen -= base;
1241 if (len > maxlen)
1242 len = maxlen;
1243
1244 xdr_stream_page_set_pos(xdr, base);
1245 base += xdr->buf->page_base;
1246
1247 pgnr = base >> PAGE_SHIFT;
1248 xdr->page_ptr = &xdr->buf->pages[pgnr];
1249 kaddr = page_address(*xdr->page_ptr);
1250
1251 pgoff = base & ~PAGE_MASK;
1252 xdr->p = (__be32*)(kaddr + pgoff);
1253
1254 pgend = pgoff + len;
1255 if (pgend > PAGE_SIZE)
1256 pgend = PAGE_SIZE;
1257 xdr->end = (__be32*)(kaddr + pgend);
1258 xdr->iov = NULL;
1259 return len;
1260 }
1261
1262 static void xdr_set_page(struct xdr_stream *xdr, unsigned int base,
1263 unsigned int len)
1264 {
1265 if (xdr_set_page_base(xdr, base, len) == 0) {
1266 base -= xdr->buf->page_len;
1267 xdr_set_tail_base(xdr, base, len);
1268 }
1269 }
1270
1271 static void xdr_set_next_page(struct xdr_stream *xdr)
1272 {
1273 unsigned int newbase;
1274
1275 newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT;
1276 newbase -= xdr->buf->page_base;
1277 if (newbase < xdr->buf->page_len)
1278 xdr_set_page_base(xdr, newbase, xdr_stream_remaining(xdr));
1279 else
1280 xdr_set_tail_base(xdr, 0, xdr_stream_remaining(xdr));
1281 }
1282
1283 static bool xdr_set_next_buffer(struct xdr_stream *xdr)
1284 {
1285 if (xdr->page_ptr != NULL)
1286 xdr_set_next_page(xdr);
1287 else if (xdr->iov == xdr->buf->head)
1288 xdr_set_page(xdr, 0, xdr_stream_remaining(xdr));
1289 return xdr->p != xdr->end;
1290 }
1291
1292 /**
1293 * xdr_init_decode - Initialize an xdr_stream for decoding data.
1294 * @xdr: pointer to xdr_stream struct
1295 * @buf: pointer to XDR buffer from which to decode data
1296 * @p: current pointer inside XDR buffer
1297 * @rqst: pointer to controlling rpc_rqst, for debugging
1298 */
1299 void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
1300 struct rpc_rqst *rqst)
1301 {
1302 xdr->buf = buf;
1303 xdr_reset_scratch_buffer(xdr);
1304 xdr->nwords = XDR_QUADLEN(buf->len);
1305 if (xdr_set_iov(xdr, buf->head, 0, buf->len) == 0 &&
1306 xdr_set_page_base(xdr, 0, buf->len) == 0)
1307 xdr_set_iov(xdr, buf->tail, 0, buf->len);
1308 if (p != NULL && p > xdr->p && xdr->end >= p) {
1309 xdr->nwords -= p - xdr->p;
1310 xdr->p = p;
1311 }
1312 xdr->rqst = rqst;
1313 }
1314 EXPORT_SYMBOL_GPL(xdr_init_decode);
1315
1316 /**
1317 * xdr_init_decode_pages - Initialize an xdr_stream for decoding into pages
1318 * @xdr: pointer to xdr_stream struct
1319 * @buf: pointer to XDR buffer from which to decode data
1320 * @pages: list of pages to decode into
1321 * @len: length in bytes of buffer in pages
1322 */
1323 void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
1324 struct page **pages, unsigned int len)
1325 {
1326 memset(buf, 0, sizeof(*buf));
1327 buf->pages = pages;
1328 buf->page_len = len;
1329 buf->buflen = len;
1330 buf->len = len;
1331 xdr_init_decode(xdr, buf, NULL, NULL);
1332 }
1333 EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
1334
1335 static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
1336 {
1337 unsigned int nwords = XDR_QUADLEN(nbytes);
1338 __be32 *p = xdr->p;
1339 __be32 *q = p + nwords;
1340
1341 if (unlikely(nwords > xdr->nwords || q > xdr->end || q < p))
1342 return NULL;
1343 xdr->p = q;
1344 xdr->nwords -= nwords;
1345 return p;
1346 }
1347
1348 static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes)
1349 {
1350 __be32 *p;
1351 char *cpdest = xdr->scratch.iov_base;
1352 size_t cplen = (char *)xdr->end - (char *)xdr->p;
1353
1354 if (nbytes > xdr->scratch.iov_len)
1355 goto out_overflow;
1356 p = __xdr_inline_decode(xdr, cplen);
1357 if (p == NULL)
1358 return NULL;
1359 memcpy(cpdest, p, cplen);
1360 if (!xdr_set_next_buffer(xdr))
1361 goto out_overflow;
1362 cpdest += cplen;
1363 nbytes -= cplen;
1364 p = __xdr_inline_decode(xdr, nbytes);
1365 if (p == NULL)
1366 return NULL;
1367 memcpy(cpdest, p, nbytes);
1368 return xdr->scratch.iov_base;
1369 out_overflow:
1370 trace_rpc_xdr_overflow(xdr, nbytes);
1371 return NULL;
1372 }
1373
1374 /**
1375 * xdr_inline_decode - Retrieve XDR data to decode
1376 * @xdr: pointer to xdr_stream struct
1377 * @nbytes: number of bytes of data to decode
1378 *
1379 * Check if the input buffer is long enough to enable us to decode
1380 * 'nbytes' more bytes of data starting at the current position.
1381 * If so return the current pointer, then update the current
1382 * pointer position.
1383 */
1384 __be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
1385 {
1386 __be32 *p;
1387
1388 if (unlikely(nbytes == 0))
1389 return xdr->p;
1390 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
1391 goto out_overflow;
1392 p = __xdr_inline_decode(xdr, nbytes);
1393 if (p != NULL)
1394 return p;
1395 return xdr_copy_to_scratch(xdr, nbytes);
1396 out_overflow:
1397 trace_rpc_xdr_overflow(xdr, nbytes);
1398 return NULL;
1399 }
1400 EXPORT_SYMBOL_GPL(xdr_inline_decode);
1401
1402 static void xdr_realign_pages(struct xdr_stream *xdr)
1403 {
1404 struct xdr_buf *buf = xdr->buf;
1405 struct kvec *iov = buf->head;
1406 unsigned int cur = xdr_stream_pos(xdr);
1407 unsigned int copied;
1408
1409 /* Realign pages to current pointer position */
1410 if (iov->iov_len > cur) {
1411 copied = xdr_shrink_bufhead(buf, cur);
1412 trace_rpc_xdr_alignment(xdr, cur, copied);
1413 xdr_set_page(xdr, 0, buf->page_len);
1414 }
1415 }
1416
1417 static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len)
1418 {
1419 struct xdr_buf *buf = xdr->buf;
1420 unsigned int nwords = XDR_QUADLEN(len);
1421 unsigned int copied;
1422
1423 if (xdr->nwords == 0)
1424 return 0;
1425
1426 xdr_realign_pages(xdr);
1427 if (nwords > xdr->nwords) {
1428 nwords = xdr->nwords;
1429 len = nwords << 2;
1430 }
1431 if (buf->page_len <= len)
1432 len = buf->page_len;
1433 else if (nwords < xdr->nwords) {
1434 /* Truncate page data and move it into the tail */
1435 copied = xdr_shrink_pagelen(buf, len);
1436 trace_rpc_xdr_alignment(xdr, len, copied);
1437 }
1438 return len;
1439 }
1440
1441 /**
1442 * xdr_read_pages - align page-based XDR data to current pointer position
1443 * @xdr: pointer to xdr_stream struct
1444 * @len: number of bytes of page data
1445 *
1446 * Moves data beyond the current pointer position from the XDR head[] buffer
1447 * into the page list. Any data that lies beyond current position + @len
1448 * bytes is moved into the XDR tail[]. The xdr_stream current position is
1449 * then advanced past that data to align to the next XDR object in the tail.
1450 *
1451 * Returns the number of XDR encoded bytes now contained in the pages
1452 */
1453 unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
1454 {
1455 unsigned int nwords = XDR_QUADLEN(len);
1456 unsigned int base, end, pglen;
1457
1458 pglen = xdr_align_pages(xdr, nwords << 2);
1459 if (pglen == 0)
1460 return 0;
1461
1462 base = (nwords << 2) - pglen;
1463 end = xdr_stream_remaining(xdr) - pglen;
1464
1465 xdr_set_tail_base(xdr, base, end);
1466 return len <= pglen ? len : pglen;
1467 }
1468 EXPORT_SYMBOL_GPL(xdr_read_pages);
1469
1470 unsigned int xdr_align_data(struct xdr_stream *xdr, unsigned int offset,
1471 unsigned int length)
1472 {
1473 struct xdr_buf *buf = xdr->buf;
1474 unsigned int from, bytes, len;
1475 unsigned int shift;
1476
1477 xdr_realign_pages(xdr);
1478 from = xdr_page_pos(xdr);
1479
1480 if (from >= buf->page_len + buf->tail->iov_len)
1481 return 0;
1482 if (from + buf->head->iov_len >= buf->len)
1483 return 0;
1484
1485 len = buf->len - buf->head->iov_len;
1486
1487 /* We only shift data left! */
1488 if (WARN_ONCE(from < offset, "SUNRPC: misaligned data src=%u dst=%u\n",
1489 from, offset))
1490 return 0;
1491 if (WARN_ONCE(offset > buf->page_len,
1492 "SUNRPC: buffer overflow. offset=%u, page_len=%u\n",
1493 offset, buf->page_len))
1494 return 0;
1495
1496 /* Move page data to the left */
1497 shift = from - offset;
1498 xdr_buf_pages_shift_left(buf, from, len, shift);
1499
1500 bytes = xdr_stream_remaining(xdr);
1501 if (length > bytes)
1502 length = bytes;
1503 bytes -= length;
1504
1505 xdr->buf->len -= shift;
1506 xdr_set_page(xdr, offset + length, bytes);
1507 return length;
1508 }
1509 EXPORT_SYMBOL_GPL(xdr_align_data);
1510
1511 unsigned int xdr_expand_hole(struct xdr_stream *xdr, unsigned int offset,
1512 unsigned int length)
1513 {
1514 struct xdr_buf *buf = xdr->buf;
1515 unsigned int from, to, shift;
1516
1517 xdr_realign_pages(xdr);
1518 from = xdr_page_pos(xdr);
1519 to = xdr_align_size(offset + length);
1520
1521 /* Could the hole be behind us? */
1522 if (to > from) {
1523 unsigned int buflen = buf->len - buf->head->iov_len;
1524 shift = to - from;
1525 xdr_buf_try_expand(buf, shift);
1526 xdr_buf_pages_shift_right(buf, from, buflen, shift);
1527 xdr_set_page(xdr, to, xdr_stream_remaining(xdr));
1528 } else if (to != from)
1529 xdr_align_data(xdr, to, 0);
1530 xdr_buf_pages_zero(buf, offset, length);
1531
1532 return length;
1533 }
1534 EXPORT_SYMBOL_GPL(xdr_expand_hole);
1535
1536 /**
1537 * xdr_enter_page - decode data from the XDR page
1538 * @xdr: pointer to xdr_stream struct
1539 * @len: number of bytes of page data
1540 *
1541 * Moves data beyond the current pointer position from the XDR head[] buffer
1542 * into the page list. Any data that lies beyond current position + "len"
1543 * bytes is moved into the XDR tail[]. The current pointer is then
1544 * repositioned at the beginning of the first XDR page.
1545 */
1546 void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
1547 {
1548 len = xdr_align_pages(xdr, len);
1549 /*
1550 * Position current pointer at beginning of tail, and
1551 * set remaining message length.
1552 */
1553 if (len != 0)
1554 xdr_set_page_base(xdr, 0, len);
1555 }
1556 EXPORT_SYMBOL_GPL(xdr_enter_page);
1557
1558 static const struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0};
1559
1560 void xdr_buf_from_iov(const struct kvec *iov, struct xdr_buf *buf)
1561 {
1562 buf->head[0] = *iov;
1563 buf->tail[0] = empty_iov;
1564 buf->page_len = 0;
1565 buf->buflen = buf->len = iov->iov_len;
1566 }
1567 EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
1568
1569 /**
1570 * xdr_buf_subsegment - set subbuf to a portion of buf
1571 * @buf: an xdr buffer
1572 * @subbuf: the result buffer
1573 * @base: beginning of range in bytes
1574 * @len: length of range in bytes
1575 *
1576 * sets @subbuf to an xdr buffer representing the portion of @buf of
1577 * length @len starting at offset @base.
1578 *
1579 * @buf and @subbuf may be pointers to the same struct xdr_buf.
1580 *
1581 * Returns -1 if base of length are out of bounds.
1582 */
1583 int xdr_buf_subsegment(const struct xdr_buf *buf, struct xdr_buf *subbuf,
1584 unsigned int base, unsigned int len)
1585 {
1586 subbuf->buflen = subbuf->len = len;
1587 if (base < buf->head[0].iov_len) {
1588 subbuf->head[0].iov_base = buf->head[0].iov_base + base;
1589 subbuf->head[0].iov_len = min_t(unsigned int, len,
1590 buf->head[0].iov_len - base);
1591 len -= subbuf->head[0].iov_len;
1592 base = 0;
1593 } else {
1594 base -= buf->head[0].iov_len;
1595 subbuf->head[0].iov_base = buf->head[0].iov_base;
1596 subbuf->head[0].iov_len = 0;
1597 }
1598
1599 if (base < buf->page_len) {
1600 subbuf->page_len = min(buf->page_len - base, len);
1601 base += buf->page_base;
1602 subbuf->page_base = base & ~PAGE_MASK;
1603 subbuf->pages = &buf->pages[base >> PAGE_SHIFT];
1604 len -= subbuf->page_len;
1605 base = 0;
1606 } else {
1607 base -= buf->page_len;
1608 subbuf->pages = buf->pages;
1609 subbuf->page_base = 0;
1610 subbuf->page_len = 0;
1611 }
1612
1613 if (base < buf->tail[0].iov_len) {
1614 subbuf->tail[0].iov_base = buf->tail[0].iov_base + base;
1615 subbuf->tail[0].iov_len = min_t(unsigned int, len,
1616 buf->tail[0].iov_len - base);
1617 len -= subbuf->tail[0].iov_len;
1618 base = 0;
1619 } else {
1620 base -= buf->tail[0].iov_len;
1621 subbuf->tail[0].iov_base = buf->tail[0].iov_base;
1622 subbuf->tail[0].iov_len = 0;
1623 }
1624
1625 if (base || len)
1626 return -1;
1627 return 0;
1628 }
1629 EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
1630
1631 /**
1632 * xdr_stream_subsegment - set @subbuf to a portion of @xdr
1633 * @xdr: an xdr_stream set up for decoding
1634 * @subbuf: the result buffer
1635 * @nbytes: length of @xdr to extract, in bytes
1636 *
1637 * Sets up @subbuf to represent a portion of @xdr. The portion
1638 * starts at the current offset in @xdr, and extends for a length
1639 * of @nbytes. If this is successful, @xdr is advanced to the next
1640 * XDR data item following that portion.
1641 *
1642 * Return values:
1643 * %true: @subbuf has been initialized, and @xdr has been advanced.
1644 * %false: a bounds error has occurred
1645 */
1646 bool xdr_stream_subsegment(struct xdr_stream *xdr, struct xdr_buf *subbuf,
1647 unsigned int nbytes)
1648 {
1649 unsigned int start = xdr_stream_pos(xdr);
1650 unsigned int remaining, len;
1651
1652 /* Extract @subbuf and bounds-check the fn arguments */
1653 if (xdr_buf_subsegment(xdr->buf, subbuf, start, nbytes))
1654 return false;
1655
1656 /* Advance @xdr by @nbytes */
1657 for (remaining = nbytes; remaining;) {
1658 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
1659 return false;
1660
1661 len = (char *)xdr->end - (char *)xdr->p;
1662 if (remaining <= len) {
1663 xdr->p = (__be32 *)((char *)xdr->p +
1664 (remaining + xdr_pad_size(nbytes)));
1665 break;
1666 }
1667
1668 xdr->p = (__be32 *)((char *)xdr->p + len);
1669 xdr->end = xdr->p;
1670 remaining -= len;
1671 }
1672
1673 xdr_stream_set_pos(xdr, start + nbytes);
1674 return true;
1675 }
1676 EXPORT_SYMBOL_GPL(xdr_stream_subsegment);
1677
1678 /**
1679 * xdr_buf_trim - lop at most "len" bytes off the end of "buf"
1680 * @buf: buf to be trimmed
1681 * @len: number of bytes to reduce "buf" by
1682 *
1683 * Trim an xdr_buf by the given number of bytes by fixing up the lengths. Note
1684 * that it's possible that we'll trim less than that amount if the xdr_buf is
1685 * too small, or if (for instance) it's all in the head and the parser has
1686 * already read too far into it.
1687 */
1688 void xdr_buf_trim(struct xdr_buf *buf, unsigned int len)
1689 {
1690 size_t cur;
1691 unsigned int trim = len;
1692
1693 if (buf->tail[0].iov_len) {
1694 cur = min_t(size_t, buf->tail[0].iov_len, trim);
1695 buf->tail[0].iov_len -= cur;
1696 trim -= cur;
1697 if (!trim)
1698 goto fix_len;
1699 }
1700
1701 if (buf->page_len) {
1702 cur = min_t(unsigned int, buf->page_len, trim);
1703 buf->page_len -= cur;
1704 trim -= cur;
1705 if (!trim)
1706 goto fix_len;
1707 }
1708
1709 if (buf->head[0].iov_len) {
1710 cur = min_t(size_t, buf->head[0].iov_len, trim);
1711 buf->head[0].iov_len -= cur;
1712 trim -= cur;
1713 }
1714 fix_len:
1715 buf->len -= (len - trim);
1716 }
1717 EXPORT_SYMBOL_GPL(xdr_buf_trim);
1718
1719 static void __read_bytes_from_xdr_buf(const struct xdr_buf *subbuf,
1720 void *obj, unsigned int len)
1721 {
1722 unsigned int this_len;
1723
1724 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1725 memcpy(obj, subbuf->head[0].iov_base, this_len);
1726 len -= this_len;
1727 obj += this_len;
1728 this_len = min_t(unsigned int, len, subbuf->page_len);
1729 _copy_from_pages(obj, subbuf->pages, subbuf->page_base, this_len);
1730 len -= this_len;
1731 obj += this_len;
1732 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1733 memcpy(obj, subbuf->tail[0].iov_base, this_len);
1734 }
1735
1736 /* obj is assumed to point to allocated memory of size at least len: */
1737 int read_bytes_from_xdr_buf(const struct xdr_buf *buf, unsigned int base,
1738 void *obj, unsigned int len)
1739 {
1740 struct xdr_buf subbuf;
1741 int status;
1742
1743 status = xdr_buf_subsegment(buf, &subbuf, base, len);
1744 if (status != 0)
1745 return status;
1746 __read_bytes_from_xdr_buf(&subbuf, obj, len);
1747 return 0;
1748 }
1749 EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf);
1750
1751 static void __write_bytes_to_xdr_buf(const struct xdr_buf *subbuf,
1752 void *obj, unsigned int len)
1753 {
1754 unsigned int this_len;
1755
1756 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1757 memcpy(subbuf->head[0].iov_base, obj, this_len);
1758 len -= this_len;
1759 obj += this_len;
1760 this_len = min_t(unsigned int, len, subbuf->page_len);
1761 _copy_to_pages(subbuf->pages, subbuf->page_base, obj, this_len);
1762 len -= this_len;
1763 obj += this_len;
1764 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1765 memcpy(subbuf->tail[0].iov_base, obj, this_len);
1766 }
1767
1768 /* obj is assumed to point to allocated memory of size at least len: */
1769 int write_bytes_to_xdr_buf(const struct xdr_buf *buf, unsigned int base,
1770 void *obj, unsigned int len)
1771 {
1772 struct xdr_buf subbuf;
1773 int status;
1774
1775 status = xdr_buf_subsegment(buf, &subbuf, base, len);
1776 if (status != 0)
1777 return status;
1778 __write_bytes_to_xdr_buf(&subbuf, obj, len);
1779 return 0;
1780 }
1781 EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf);
1782
1783 int xdr_decode_word(const struct xdr_buf *buf, unsigned int base, u32 *obj)
1784 {
1785 __be32 raw;
1786 int status;
1787
1788 status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
1789 if (status)
1790 return status;
1791 *obj = be32_to_cpu(raw);
1792 return 0;
1793 }
1794 EXPORT_SYMBOL_GPL(xdr_decode_word);
1795
1796 int xdr_encode_word(const struct xdr_buf *buf, unsigned int base, u32 obj)
1797 {
1798 __be32 raw = cpu_to_be32(obj);
1799
1800 return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj));
1801 }
1802 EXPORT_SYMBOL_GPL(xdr_encode_word);
1803
1804 /* Returns 0 on success, or else a negative error code. */
1805 static int xdr_xcode_array2(const struct xdr_buf *buf, unsigned int base,
1806 struct xdr_array2_desc *desc, int encode)
1807 {
1808 char *elem = NULL, *c;
1809 unsigned int copied = 0, todo, avail_here;
1810 struct page **ppages = NULL;
1811 int err;
1812
1813 if (encode) {
1814 if (xdr_encode_word(buf, base, desc->array_len) != 0)
1815 return -EINVAL;
1816 } else {
1817 if (xdr_decode_word(buf, base, &desc->array_len) != 0 ||
1818 desc->array_len > desc->array_maxlen ||
1819 (unsigned long) base + 4 + desc->array_len *
1820 desc->elem_size > buf->len)
1821 return -EINVAL;
1822 }
1823 base += 4;
1824
1825 if (!desc->xcode)
1826 return 0;
1827
1828 todo = desc->array_len * desc->elem_size;
1829
1830 /* process head */
1831 if (todo && base < buf->head->iov_len) {
1832 c = buf->head->iov_base + base;
1833 avail_here = min_t(unsigned int, todo,
1834 buf->head->iov_len - base);
1835 todo -= avail_here;
1836
1837 while (avail_here >= desc->elem_size) {
1838 err = desc->xcode(desc, c);
1839 if (err)
1840 goto out;
1841 c += desc->elem_size;
1842 avail_here -= desc->elem_size;
1843 }
1844 if (avail_here) {
1845 if (!elem) {
1846 elem = kmalloc(desc->elem_size, GFP_KERNEL);
1847 err = -ENOMEM;
1848 if (!elem)
1849 goto out;
1850 }
1851 if (encode) {
1852 err = desc->xcode(desc, elem);
1853 if (err)
1854 goto out;
1855 memcpy(c, elem, avail_here);
1856 } else
1857 memcpy(elem, c, avail_here);
1858 copied = avail_here;
1859 }
1860 base = buf->head->iov_len; /* align to start of pages */
1861 }
1862
1863 /* process pages array */
1864 base -= buf->head->iov_len;
1865 if (todo && base < buf->page_len) {
1866 unsigned int avail_page;
1867
1868 avail_here = min(todo, buf->page_len - base);
1869 todo -= avail_here;
1870
1871 base += buf->page_base;
1872 ppages = buf->pages + (base >> PAGE_SHIFT);
1873 base &= ~PAGE_MASK;
1874 avail_page = min_t(unsigned int, PAGE_SIZE - base,
1875 avail_here);
1876 c = kmap(*ppages) + base;
1877
1878 while (avail_here) {
1879 avail_here -= avail_page;
1880 if (copied || avail_page < desc->elem_size) {
1881 unsigned int l = min(avail_page,
1882 desc->elem_size - copied);
1883 if (!elem) {
1884 elem = kmalloc(desc->elem_size,
1885 GFP_KERNEL);
1886 err = -ENOMEM;
1887 if (!elem)
1888 goto out;
1889 }
1890 if (encode) {
1891 if (!copied) {
1892 err = desc->xcode(desc, elem);
1893 if (err)
1894 goto out;
1895 }
1896 memcpy(c, elem + copied, l);
1897 copied += l;
1898 if (copied == desc->elem_size)
1899 copied = 0;
1900 } else {
1901 memcpy(elem + copied, c, l);
1902 copied += l;
1903 if (copied == desc->elem_size) {
1904 err = desc->xcode(desc, elem);
1905 if (err)
1906 goto out;
1907 copied = 0;
1908 }
1909 }
1910 avail_page -= l;
1911 c += l;
1912 }
1913 while (avail_page >= desc->elem_size) {
1914 err = desc->xcode(desc, c);
1915 if (err)
1916 goto out;
1917 c += desc->elem_size;
1918 avail_page -= desc->elem_size;
1919 }
1920 if (avail_page) {
1921 unsigned int l = min(avail_page,
1922 desc->elem_size - copied);
1923 if (!elem) {
1924 elem = kmalloc(desc->elem_size,
1925 GFP_KERNEL);
1926 err = -ENOMEM;
1927 if (!elem)
1928 goto out;
1929 }
1930 if (encode) {
1931 if (!copied) {
1932 err = desc->xcode(desc, elem);
1933 if (err)
1934 goto out;
1935 }
1936 memcpy(c, elem + copied, l);
1937 copied += l;
1938 if (copied == desc->elem_size)
1939 copied = 0;
1940 } else {
1941 memcpy(elem + copied, c, l);
1942 copied += l;
1943 if (copied == desc->elem_size) {
1944 err = desc->xcode(desc, elem);
1945 if (err)
1946 goto out;
1947 copied = 0;
1948 }
1949 }
1950 }
1951 if (avail_here) {
1952 kunmap(*ppages);
1953 ppages++;
1954 c = kmap(*ppages);
1955 }
1956
1957 avail_page = min(avail_here,
1958 (unsigned int) PAGE_SIZE);
1959 }
1960 base = buf->page_len; /* align to start of tail */
1961 }
1962
1963 /* process tail */
1964 base -= buf->page_len;
1965 if (todo) {
1966 c = buf->tail->iov_base + base;
1967 if (copied) {
1968 unsigned int l = desc->elem_size - copied;
1969
1970 if (encode)
1971 memcpy(c, elem + copied, l);
1972 else {
1973 memcpy(elem + copied, c, l);
1974 err = desc->xcode(desc, elem);
1975 if (err)
1976 goto out;
1977 }
1978 todo -= l;
1979 c += l;
1980 }
1981 while (todo) {
1982 err = desc->xcode(desc, c);
1983 if (err)
1984 goto out;
1985 c += desc->elem_size;
1986 todo -= desc->elem_size;
1987 }
1988 }
1989 err = 0;
1990
1991 out:
1992 kfree(elem);
1993 if (ppages)
1994 kunmap(*ppages);
1995 return err;
1996 }
1997
1998 int xdr_decode_array2(const struct xdr_buf *buf, unsigned int base,
1999 struct xdr_array2_desc *desc)
2000 {
2001 if (base >= buf->len)
2002 return -EINVAL;
2003
2004 return xdr_xcode_array2(buf, base, desc, 0);
2005 }
2006 EXPORT_SYMBOL_GPL(xdr_decode_array2);
2007
2008 int xdr_encode_array2(const struct xdr_buf *buf, unsigned int base,
2009 struct xdr_array2_desc *desc)
2010 {
2011 if ((unsigned long) base + 4 + desc->array_len * desc->elem_size >
2012 buf->head->iov_len + buf->page_len + buf->tail->iov_len)
2013 return -EINVAL;
2014
2015 return xdr_xcode_array2(buf, base, desc, 1);
2016 }
2017 EXPORT_SYMBOL_GPL(xdr_encode_array2);
2018
2019 int xdr_process_buf(const struct xdr_buf *buf, unsigned int offset,
2020 unsigned int len,
2021 int (*actor)(struct scatterlist *, void *), void *data)
2022 {
2023 int i, ret = 0;
2024 unsigned int page_len, thislen, page_offset;
2025 struct scatterlist sg[1];
2026
2027 sg_init_table(sg, 1);
2028
2029 if (offset >= buf->head[0].iov_len) {
2030 offset -= buf->head[0].iov_len;
2031 } else {
2032 thislen = buf->head[0].iov_len - offset;
2033 if (thislen > len)
2034 thislen = len;
2035 sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
2036 ret = actor(sg, data);
2037 if (ret)
2038 goto out;
2039 offset = 0;
2040 len -= thislen;
2041 }
2042 if (len == 0)
2043 goto out;
2044
2045 if (offset >= buf->page_len) {
2046 offset -= buf->page_len;
2047 } else {
2048 page_len = buf->page_len - offset;
2049 if (page_len > len)
2050 page_len = len;
2051 len -= page_len;
2052 page_offset = (offset + buf->page_base) & (PAGE_SIZE - 1);
2053 i = (offset + buf->page_base) >> PAGE_SHIFT;
2054 thislen = PAGE_SIZE - page_offset;
2055 do {
2056 if (thislen > page_len)
2057 thislen = page_len;
2058 sg_set_page(sg, buf->pages[i], thislen, page_offset);
2059 ret = actor(sg, data);
2060 if (ret)
2061 goto out;
2062 page_len -= thislen;
2063 i++;
2064 page_offset = 0;
2065 thislen = PAGE_SIZE;
2066 } while (page_len != 0);
2067 offset = 0;
2068 }
2069 if (len == 0)
2070 goto out;
2071 if (offset < buf->tail[0].iov_len) {
2072 thislen = buf->tail[0].iov_len - offset;
2073 if (thislen > len)
2074 thislen = len;
2075 sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
2076 ret = actor(sg, data);
2077 len -= thislen;
2078 }
2079 if (len != 0)
2080 ret = -EINVAL;
2081 out:
2082 return ret;
2083 }
2084 EXPORT_SYMBOL_GPL(xdr_process_buf);
2085
2086 /**
2087 * xdr_stream_decode_opaque - Decode variable length opaque
2088 * @xdr: pointer to xdr_stream
2089 * @ptr: location to store opaque data
2090 * @size: size of storage buffer @ptr
2091 *
2092 * Return values:
2093 * On success, returns size of object stored in *@ptr
2094 * %-EBADMSG on XDR buffer overflow
2095 * %-EMSGSIZE on overflow of storage buffer @ptr
2096 */
2097 ssize_t xdr_stream_decode_opaque(struct xdr_stream *xdr, void *ptr, size_t size)
2098 {
2099 ssize_t ret;
2100 void *p;
2101
2102 ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
2103 if (ret <= 0)
2104 return ret;
2105 memcpy(ptr, p, ret);
2106 return ret;
2107 }
2108 EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque);
2109
2110 /**
2111 * xdr_stream_decode_opaque_dup - Decode and duplicate variable length opaque
2112 * @xdr: pointer to xdr_stream
2113 * @ptr: location to store pointer to opaque data
2114 * @maxlen: maximum acceptable object size
2115 * @gfp_flags: GFP mask to use
2116 *
2117 * Return values:
2118 * On success, returns size of object stored in *@ptr
2119 * %-EBADMSG on XDR buffer overflow
2120 * %-EMSGSIZE if the size of the object would exceed @maxlen
2121 * %-ENOMEM on memory allocation failure
2122 */
2123 ssize_t xdr_stream_decode_opaque_dup(struct xdr_stream *xdr, void **ptr,
2124 size_t maxlen, gfp_t gfp_flags)
2125 {
2126 ssize_t ret;
2127 void *p;
2128
2129 ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
2130 if (ret > 0) {
2131 *ptr = kmemdup(p, ret, gfp_flags);
2132 if (*ptr != NULL)
2133 return ret;
2134 ret = -ENOMEM;
2135 }
2136 *ptr = NULL;
2137 return ret;
2138 }
2139 EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque_dup);
2140
2141 /**
2142 * xdr_stream_decode_string - Decode variable length string
2143 * @xdr: pointer to xdr_stream
2144 * @str: location to store string
2145 * @size: size of storage buffer @str
2146 *
2147 * Return values:
2148 * On success, returns length of NUL-terminated string stored in *@str
2149 * %-EBADMSG on XDR buffer overflow
2150 * %-EMSGSIZE on overflow of storage buffer @str
2151 */
2152 ssize_t xdr_stream_decode_string(struct xdr_stream *xdr, char *str, size_t size)
2153 {
2154 ssize_t ret;
2155 void *p;
2156
2157 ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
2158 if (ret > 0) {
2159 memcpy(str, p, ret);
2160 str[ret] = '\0';
2161 return strlen(str);
2162 }
2163 *str = '\0';
2164 return ret;
2165 }
2166 EXPORT_SYMBOL_GPL(xdr_stream_decode_string);
2167
2168 /**
2169 * xdr_stream_decode_string_dup - Decode and duplicate variable length string
2170 * @xdr: pointer to xdr_stream
2171 * @str: location to store pointer to string
2172 * @maxlen: maximum acceptable string length
2173 * @gfp_flags: GFP mask to use
2174 *
2175 * Return values:
2176 * On success, returns length of NUL-terminated string stored in *@ptr
2177 * %-EBADMSG on XDR buffer overflow
2178 * %-EMSGSIZE if the size of the string would exceed @maxlen
2179 * %-ENOMEM on memory allocation failure
2180 */
2181 ssize_t xdr_stream_decode_string_dup(struct xdr_stream *xdr, char **str,
2182 size_t maxlen, gfp_t gfp_flags)
2183 {
2184 void *p;
2185 ssize_t ret;
2186
2187 ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
2188 if (ret > 0) {
2189 char *s = kmemdup_nul(p, ret, gfp_flags);
2190 if (s != NULL) {
2191 *str = s;
2192 return strlen(s);
2193 }
2194 ret = -ENOMEM;
2195 }
2196 *str = NULL;
2197 return ret;
2198 }
2199 EXPORT_SYMBOL_GPL(xdr_stream_decode_string_dup);
2200
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