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 bvec_set_page(&buf->bvec[i], buf->pages[i], PAGE_SIZE,
154 0);
155 }
156 }
157 return 0;
158 }
159
160 void
161 xdr_free_bvec(struct xdr_buf *buf)
162 {
163 kfree(buf->bvec);
164 buf->bvec = NULL;
165 }
166
167 /**
168 * xdr_buf_to_bvec - Copy components of an xdr_buf into a bio_vec array
169 * @bvec: bio_vec array to populate
170 * @bvec_size: element count of @bio_vec
171 * @xdr: xdr_buf to be copied
172 *
173 * Returns the number of entries consumed in @bvec.
174 */
175 unsigned int xdr_buf_to_bvec(struct bio_vec *bvec, unsigned int bvec_size,
176 const struct xdr_buf *xdr)
177 {
178 const struct kvec *head = xdr->head;
179 const struct kvec *tail = xdr->tail;
180 unsigned int count = 0;
181
182 if (head->iov_len) {
183 bvec_set_virt(bvec++, head->iov_base, head->iov_len);
184 ++count;
185 }
186
187 if (xdr->page_len) {
188 unsigned int offset, len, remaining;
189 struct page **pages = xdr->pages;
190
191 offset = offset_in_page(xdr->page_base);
192 remaining = xdr->page_len;
193 while (remaining > 0) {
194 len = min_t(unsigned int, remaining,
195 PAGE_SIZE - offset);
196 bvec_set_page(bvec++, *pages++, len, offset);
197 remaining -= len;
198 offset = 0;
199 if (unlikely(++count > bvec_size))
200 goto bvec_overflow;
201 }
202 }
203
204 if (tail->iov_len) {
205 bvec_set_virt(bvec, tail->iov_base, tail->iov_len);
206 if (unlikely(++count > bvec_size))
207 goto bvec_overflow;
208 }
209
210 return count;
211
212 bvec_overflow:
213 pr_warn_once("%s: bio_vec array overflow\n", __func__);
214 return count - 1;
215 }
216
217 /**
218 * xdr_inline_pages - Prepare receive buffer for a large reply
219 * @xdr: xdr_buf into which reply will be placed
220 * @offset: expected offset where data payload will start, in bytes
221 * @pages: vector of struct page pointers
222 * @base: offset in first page where receive should start, in bytes
223 * @len: expected size of the upper layer data payload, in bytes
224 *
225 */
226 void
227 xdr_inline_pages(struct xdr_buf *xdr, unsigned int offset,
228 struct page **pages, unsigned int base, unsigned int len)
229 {
230 struct kvec *head = xdr->head;
231 struct kvec *tail = xdr->tail;
232 char *buf = (char *)head->iov_base;
233 unsigned int buflen = head->iov_len;
234
235 head->iov_len = offset;
236
237 xdr->pages = pages;
238 xdr->page_base = base;
239 xdr->page_len = len;
240
241 tail->iov_base = buf + offset;
242 tail->iov_len = buflen - offset;
243 xdr->buflen += len;
244 }
245 EXPORT_SYMBOL_GPL(xdr_inline_pages);
246
247 /*
248 * Helper routines for doing 'memmove' like operations on a struct xdr_buf
249 */
250
251 /**
252 * _shift_data_left_pages
253 * @pages: vector of pages containing both the source and dest memory area.
254 * @pgto_base: page vector address of destination
255 * @pgfrom_base: page vector address of source
256 * @len: number of bytes to copy
257 *
258 * Note: the addresses pgto_base and pgfrom_base are both calculated in
259 * the same way:
260 * if a memory area starts at byte 'base' in page 'pages[i]',
261 * then its address is given as (i << PAGE_CACHE_SHIFT) + base
262 * Alse note: pgto_base must be < pgfrom_base, but the memory areas
263 * they point to may overlap.
264 */
265 static void
266 _shift_data_left_pages(struct page **pages, size_t pgto_base,
267 size_t pgfrom_base, size_t len)
268 {
269 struct page **pgfrom, **pgto;
270 char *vfrom, *vto;
271 size_t copy;
272
273 BUG_ON(pgfrom_base <= pgto_base);
274
275 if (!len)
276 return;
277
278 pgto = pages + (pgto_base >> PAGE_SHIFT);
279 pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);
280
281 pgto_base &= ~PAGE_MASK;
282 pgfrom_base &= ~PAGE_MASK;
283
284 do {
285 if (pgto_base >= PAGE_SIZE) {
286 pgto_base = 0;
287 pgto++;
288 }
289 if (pgfrom_base >= PAGE_SIZE){
290 pgfrom_base = 0;
291 pgfrom++;
292 }
293
294 copy = len;
295 if (copy > (PAGE_SIZE - pgto_base))
296 copy = PAGE_SIZE - pgto_base;
297 if (copy > (PAGE_SIZE - pgfrom_base))
298 copy = PAGE_SIZE - pgfrom_base;
299
300 vto = kmap_atomic(*pgto);
301 if (*pgto != *pgfrom) {
302 vfrom = kmap_atomic(*pgfrom);
303 memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);
304 kunmap_atomic(vfrom);
305 } else
306 memmove(vto + pgto_base, vto + pgfrom_base, copy);
307 flush_dcache_page(*pgto);
308 kunmap_atomic(vto);
309
310 pgto_base += copy;
311 pgfrom_base += copy;
312
313 } while ((len -= copy) != 0);
314 }
315
316 /**
317 * _shift_data_right_pages
318 * @pages: vector of pages containing both the source and dest memory area.
319 * @pgto_base: page vector address of destination
320 * @pgfrom_base: page vector address of source
321 * @len: number of bytes to copy
322 *
323 * Note: the addresses pgto_base and pgfrom_base are both calculated in
324 * the same way:
325 * if a memory area starts at byte 'base' in page 'pages[i]',
326 * then its address is given as (i << PAGE_SHIFT) + base
327 * Also note: pgfrom_base must be < pgto_base, but the memory areas
328 * they point to may overlap.
329 */
330 static void
331 _shift_data_right_pages(struct page **pages, size_t pgto_base,
332 size_t pgfrom_base, size_t len)
333 {
334 struct page **pgfrom, **pgto;
335 char *vfrom, *vto;
336 size_t copy;
337
338 BUG_ON(pgto_base <= pgfrom_base);
339
340 if (!len)
341 return;
342
343 pgto_base += len;
344 pgfrom_base += len;
345
346 pgto = pages + (pgto_base >> PAGE_SHIFT);
347 pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);
348
349 pgto_base &= ~PAGE_MASK;
350 pgfrom_base &= ~PAGE_MASK;
351
352 do {
353 /* Are any pointers crossing a page boundary? */
354 if (pgto_base == 0) {
355 pgto_base = PAGE_SIZE;
356 pgto--;
357 }
358 if (pgfrom_base == 0) {
359 pgfrom_base = PAGE_SIZE;
360 pgfrom--;
361 }
362
363 copy = len;
364 if (copy > pgto_base)
365 copy = pgto_base;
366 if (copy > pgfrom_base)
367 copy = pgfrom_base;
368 pgto_base -= copy;
369 pgfrom_base -= copy;
370
371 vto = kmap_atomic(*pgto);
372 if (*pgto != *pgfrom) {
373 vfrom = kmap_atomic(*pgfrom);
374 memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);
375 kunmap_atomic(vfrom);
376 } else
377 memmove(vto + pgto_base, vto + pgfrom_base, copy);
378 flush_dcache_page(*pgto);
379 kunmap_atomic(vto);
380
381 } while ((len -= copy) != 0);
382 }
383
384 /**
385 * _copy_to_pages
386 * @pages: array of pages
387 * @pgbase: page vector address of destination
388 * @p: pointer to source data
389 * @len: length
390 *
391 * Copies data from an arbitrary memory location into an array of pages
392 * The copy is assumed to be non-overlapping.
393 */
394 static void
395 _copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len)
396 {
397 struct page **pgto;
398 char *vto;
399 size_t copy;
400
401 if (!len)
402 return;
403
404 pgto = pages + (pgbase >> PAGE_SHIFT);
405 pgbase &= ~PAGE_MASK;
406
407 for (;;) {
408 copy = PAGE_SIZE - pgbase;
409 if (copy > len)
410 copy = len;
411
412 vto = kmap_atomic(*pgto);
413 memcpy(vto + pgbase, p, copy);
414 kunmap_atomic(vto);
415
416 len -= copy;
417 if (len == 0)
418 break;
419
420 pgbase += copy;
421 if (pgbase == PAGE_SIZE) {
422 flush_dcache_page(*pgto);
423 pgbase = 0;
424 pgto++;
425 }
426 p += copy;
427 }
428 flush_dcache_page(*pgto);
429 }
430
431 /**
432 * _copy_from_pages
433 * @p: pointer to destination
434 * @pages: array of pages
435 * @pgbase: offset of source data
436 * @len: length
437 *
438 * Copies data into an arbitrary memory location from an array of pages
439 * The copy is assumed to be non-overlapping.
440 */
441 void
442 _copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
443 {
444 struct page **pgfrom;
445 char *vfrom;
446 size_t copy;
447
448 if (!len)
449 return;
450
451 pgfrom = pages + (pgbase >> PAGE_SHIFT);
452 pgbase &= ~PAGE_MASK;
453
454 do {
455 copy = PAGE_SIZE - pgbase;
456 if (copy > len)
457 copy = len;
458
459 vfrom = kmap_atomic(*pgfrom);
460 memcpy(p, vfrom + pgbase, copy);
461 kunmap_atomic(vfrom);
462
463 pgbase += copy;
464 if (pgbase == PAGE_SIZE) {
465 pgbase = 0;
466 pgfrom++;
467 }
468 p += copy;
469
470 } while ((len -= copy) != 0);
471 }
472 EXPORT_SYMBOL_GPL(_copy_from_pages);
473
474 static void xdr_buf_iov_zero(const struct kvec *iov, unsigned int base,
475 unsigned int len)
476 {
477 if (base >= iov->iov_len)
478 return;
479 if (len > iov->iov_len - base)
480 len = iov->iov_len - base;
481 memset(iov->iov_base + base, 0, len);
482 }
483
484 /**
485 * xdr_buf_pages_zero
486 * @buf: xdr_buf
487 * @pgbase: beginning offset
488 * @len: length
489 */
490 static void xdr_buf_pages_zero(const struct xdr_buf *buf, unsigned int pgbase,
491 unsigned int len)
492 {
493 struct page **pages = buf->pages;
494 struct page **page;
495 char *vpage;
496 unsigned int zero;
497
498 if (!len)
499 return;
500 if (pgbase >= buf->page_len) {
501 xdr_buf_iov_zero(buf->tail, pgbase - buf->page_len, len);
502 return;
503 }
504 if (pgbase + len > buf->page_len) {
505 xdr_buf_iov_zero(buf->tail, 0, pgbase + len - buf->page_len);
506 len = buf->page_len - pgbase;
507 }
508
509 pgbase += buf->page_base;
510
511 page = pages + (pgbase >> PAGE_SHIFT);
512 pgbase &= ~PAGE_MASK;
513
514 do {
515 zero = PAGE_SIZE - pgbase;
516 if (zero > len)
517 zero = len;
518
519 vpage = kmap_atomic(*page);
520 memset(vpage + pgbase, 0, zero);
521 kunmap_atomic(vpage);
522
523 flush_dcache_page(*page);
524 pgbase = 0;
525 page++;
526
527 } while ((len -= zero) != 0);
528 }
529
530 static unsigned int xdr_buf_pages_fill_sparse(const struct xdr_buf *buf,
531 unsigned int buflen, gfp_t gfp)
532 {
533 unsigned int i, npages, pagelen;
534
535 if (!(buf->flags & XDRBUF_SPARSE_PAGES))
536 return buflen;
537 if (buflen <= buf->head->iov_len)
538 return buflen;
539 pagelen = buflen - buf->head->iov_len;
540 if (pagelen > buf->page_len)
541 pagelen = buf->page_len;
542 npages = (pagelen + buf->page_base + PAGE_SIZE - 1) >> PAGE_SHIFT;
543 for (i = 0; i < npages; i++) {
544 if (!buf->pages[i])
545 continue;
546 buf->pages[i] = alloc_page(gfp);
547 if (likely(buf->pages[i]))
548 continue;
549 buflen -= pagelen;
550 pagelen = i << PAGE_SHIFT;
551 if (pagelen > buf->page_base)
552 buflen += pagelen - buf->page_base;
553 break;
554 }
555 return buflen;
556 }
557
558 static void xdr_buf_try_expand(struct xdr_buf *buf, unsigned int len)
559 {
560 struct kvec *head = buf->head;
561 struct kvec *tail = buf->tail;
562 unsigned int sum = head->iov_len + buf->page_len + tail->iov_len;
563 unsigned int free_space, newlen;
564
565 if (sum > buf->len) {
566 free_space = min_t(unsigned int, sum - buf->len, len);
567 newlen = xdr_buf_pages_fill_sparse(buf, buf->len + free_space,
568 GFP_KERNEL);
569 free_space = newlen - buf->len;
570 buf->len = newlen;
571 len -= free_space;
572 if (!len)
573 return;
574 }
575
576 if (buf->buflen > sum) {
577 /* Expand the tail buffer */
578 free_space = min_t(unsigned int, buf->buflen - sum, len);
579 tail->iov_len += free_space;
580 buf->len += free_space;
581 }
582 }
583
584 static void xdr_buf_tail_copy_right(const struct xdr_buf *buf,
585 unsigned int base, unsigned int len,
586 unsigned int shift)
587 {
588 const struct kvec *tail = buf->tail;
589 unsigned int to = base + shift;
590
591 if (to >= tail->iov_len)
592 return;
593 if (len + to > tail->iov_len)
594 len = tail->iov_len - to;
595 memmove(tail->iov_base + to, tail->iov_base + base, len);
596 }
597
598 static void xdr_buf_pages_copy_right(const struct xdr_buf *buf,
599 unsigned int base, unsigned int len,
600 unsigned int shift)
601 {
602 const struct kvec *tail = buf->tail;
603 unsigned int to = base + shift;
604 unsigned int pglen = 0;
605 unsigned int talen = 0, tato = 0;
606
607 if (base >= buf->page_len)
608 return;
609 if (len > buf->page_len - base)
610 len = buf->page_len - base;
611 if (to >= buf->page_len) {
612 tato = to - buf->page_len;
613 if (tail->iov_len >= len + tato)
614 talen = len;
615 else if (tail->iov_len > tato)
616 talen = tail->iov_len - tato;
617 } else if (len + to >= buf->page_len) {
618 pglen = buf->page_len - to;
619 talen = len - pglen;
620 if (talen > tail->iov_len)
621 talen = tail->iov_len;
622 } else
623 pglen = len;
624
625 _copy_from_pages(tail->iov_base + tato, buf->pages,
626 buf->page_base + base + pglen, talen);
627 _shift_data_right_pages(buf->pages, buf->page_base + to,
628 buf->page_base + base, pglen);
629 }
630
631 static void xdr_buf_head_copy_right(const struct xdr_buf *buf,
632 unsigned int base, unsigned int len,
633 unsigned int shift)
634 {
635 const struct kvec *head = buf->head;
636 const struct kvec *tail = buf->tail;
637 unsigned int to = base + shift;
638 unsigned int pglen = 0, pgto = 0;
639 unsigned int talen = 0, tato = 0;
640
641 if (base >= head->iov_len)
642 return;
643 if (len > head->iov_len - base)
644 len = head->iov_len - base;
645 if (to >= buf->page_len + head->iov_len) {
646 tato = to - buf->page_len - head->iov_len;
647 talen = len;
648 } else if (to >= head->iov_len) {
649 pgto = to - head->iov_len;
650 pglen = len;
651 if (pgto + pglen > buf->page_len) {
652 talen = pgto + pglen - buf->page_len;
653 pglen -= talen;
654 }
655 } else {
656 pglen = len - to;
657 if (pglen > buf->page_len) {
658 talen = pglen - buf->page_len;
659 pglen = buf->page_len;
660 }
661 }
662
663 len -= talen;
664 base += len;
665 if (talen + tato > tail->iov_len)
666 talen = tail->iov_len > tato ? tail->iov_len - tato : 0;
667 memcpy(tail->iov_base + tato, head->iov_base + base, talen);
668
669 len -= pglen;
670 base -= pglen;
671 _copy_to_pages(buf->pages, buf->page_base + pgto, head->iov_base + base,
672 pglen);
673
674 base -= len;
675 memmove(head->iov_base + to, head->iov_base + base, len);
676 }
677
678 static void xdr_buf_tail_shift_right(const struct xdr_buf *buf,
679 unsigned int base, unsigned int len,
680 unsigned int shift)
681 {
682 const struct kvec *tail = buf->tail;
683
684 if (base >= tail->iov_len || !shift || !len)
685 return;
686 xdr_buf_tail_copy_right(buf, base, len, shift);
687 }
688
689 static void xdr_buf_pages_shift_right(const struct xdr_buf *buf,
690 unsigned int base, unsigned int len,
691 unsigned int shift)
692 {
693 if (!shift || !len)
694 return;
695 if (base >= buf->page_len) {
696 xdr_buf_tail_shift_right(buf, base - buf->page_len, len, shift);
697 return;
698 }
699 if (base + len > buf->page_len)
700 xdr_buf_tail_shift_right(buf, 0, base + len - buf->page_len,
701 shift);
702 xdr_buf_pages_copy_right(buf, base, len, shift);
703 }
704
705 static void xdr_buf_head_shift_right(const struct xdr_buf *buf,
706 unsigned int base, unsigned int len,
707 unsigned int shift)
708 {
709 const struct kvec *head = buf->head;
710
711 if (!shift)
712 return;
713 if (base >= head->iov_len) {
714 xdr_buf_pages_shift_right(buf, head->iov_len - base, len,
715 shift);
716 return;
717 }
718 if (base + len > head->iov_len)
719 xdr_buf_pages_shift_right(buf, 0, base + len - head->iov_len,
720 shift);
721 xdr_buf_head_copy_right(buf, base, len, shift);
722 }
723
724 static void xdr_buf_tail_copy_left(const struct xdr_buf *buf, unsigned int base,
725 unsigned int len, unsigned int shift)
726 {
727 const struct kvec *tail = buf->tail;
728
729 if (base >= tail->iov_len)
730 return;
731 if (len > tail->iov_len - base)
732 len = tail->iov_len - base;
733 /* Shift data into head */
734 if (shift > buf->page_len + base) {
735 const struct kvec *head = buf->head;
736 unsigned int hdto =
737 head->iov_len + buf->page_len + base - shift;
738 unsigned int hdlen = len;
739
740 if (WARN_ONCE(shift > head->iov_len + buf->page_len + base,
741 "SUNRPC: Misaligned data.\n"))
742 return;
743 if (hdto + hdlen > head->iov_len)
744 hdlen = head->iov_len - hdto;
745 memcpy(head->iov_base + hdto, tail->iov_base + base, hdlen);
746 base += hdlen;
747 len -= hdlen;
748 if (!len)
749 return;
750 }
751 /* Shift data into pages */
752 if (shift > base) {
753 unsigned int pgto = buf->page_len + base - shift;
754 unsigned int pglen = len;
755
756 if (pgto + pglen > buf->page_len)
757 pglen = buf->page_len - pgto;
758 _copy_to_pages(buf->pages, buf->page_base + pgto,
759 tail->iov_base + base, pglen);
760 base += pglen;
761 len -= pglen;
762 if (!len)
763 return;
764 }
765 memmove(tail->iov_base + base - shift, tail->iov_base + base, len);
766 }
767
768 static void xdr_buf_pages_copy_left(const struct xdr_buf *buf,
769 unsigned int base, unsigned int len,
770 unsigned int shift)
771 {
772 unsigned int pgto;
773
774 if (base >= buf->page_len)
775 return;
776 if (len > buf->page_len - base)
777 len = buf->page_len - base;
778 /* Shift data into head */
779 if (shift > base) {
780 const struct kvec *head = buf->head;
781 unsigned int hdto = head->iov_len + base - shift;
782 unsigned int hdlen = len;
783
784 if (WARN_ONCE(shift > head->iov_len + base,
785 "SUNRPC: Misaligned data.\n"))
786 return;
787 if (hdto + hdlen > head->iov_len)
788 hdlen = head->iov_len - hdto;
789 _copy_from_pages(head->iov_base + hdto, buf->pages,
790 buf->page_base + base, hdlen);
791 base += hdlen;
792 len -= hdlen;
793 if (!len)
794 return;
795 }
796 pgto = base - shift;
797 _shift_data_left_pages(buf->pages, buf->page_base + pgto,
798 buf->page_base + base, len);
799 }
800
801 static void xdr_buf_tail_shift_left(const struct xdr_buf *buf,
802 unsigned int base, unsigned int len,
803 unsigned int shift)
804 {
805 if (!shift || !len)
806 return;
807 xdr_buf_tail_copy_left(buf, base, len, shift);
808 }
809
810 static void xdr_buf_pages_shift_left(const struct xdr_buf *buf,
811 unsigned int base, unsigned int len,
812 unsigned int shift)
813 {
814 if (!shift || !len)
815 return;
816 if (base >= buf->page_len) {
817 xdr_buf_tail_shift_left(buf, base - buf->page_len, len, shift);
818 return;
819 }
820 xdr_buf_pages_copy_left(buf, base, len, shift);
821 len += base;
822 if (len <= buf->page_len)
823 return;
824 xdr_buf_tail_copy_left(buf, 0, len - buf->page_len, shift);
825 }
826
827 static void xdr_buf_head_shift_left(const struct xdr_buf *buf,
828 unsigned int base, unsigned int len,
829 unsigned int shift)
830 {
831 const struct kvec *head = buf->head;
832 unsigned int bytes;
833
834 if (!shift || !len)
835 return;
836
837 if (shift > base) {
838 bytes = (shift - base);
839 if (bytes >= len)
840 return;
841 base += bytes;
842 len -= bytes;
843 }
844
845 if (base < head->iov_len) {
846 bytes = min_t(unsigned int, len, head->iov_len - base);
847 memmove(head->iov_base + (base - shift),
848 head->iov_base + base, bytes);
849 base += bytes;
850 len -= bytes;
851 }
852 xdr_buf_pages_shift_left(buf, base - head->iov_len, len, shift);
853 }
854
855 /**
856 * xdr_shrink_bufhead
857 * @buf: xdr_buf
858 * @len: new length of buf->head[0]
859 *
860 * Shrinks XDR buffer's header kvec buf->head[0], setting it to
861 * 'len' bytes. The extra data is not lost, but is instead
862 * moved into the inlined pages and/or the tail.
863 */
864 static unsigned int xdr_shrink_bufhead(struct xdr_buf *buf, unsigned int len)
865 {
866 struct kvec *head = buf->head;
867 unsigned int shift, buflen = max(buf->len, len);
868
869 WARN_ON_ONCE(len > head->iov_len);
870 if (head->iov_len > buflen) {
871 buf->buflen -= head->iov_len - buflen;
872 head->iov_len = buflen;
873 }
874 if (len >= head->iov_len)
875 return 0;
876 shift = head->iov_len - len;
877 xdr_buf_try_expand(buf, shift);
878 xdr_buf_head_shift_right(buf, len, buflen - len, shift);
879 head->iov_len = len;
880 buf->buflen -= shift;
881 buf->len -= shift;
882 return shift;
883 }
884
885 /**
886 * xdr_shrink_pagelen - shrinks buf->pages to @len bytes
887 * @buf: xdr_buf
888 * @len: new page buffer length
889 *
890 * The extra data is not lost, but is instead moved into buf->tail.
891 * Returns the actual number of bytes moved.
892 */
893 static unsigned int xdr_shrink_pagelen(struct xdr_buf *buf, unsigned int len)
894 {
895 unsigned int shift, buflen = buf->len - buf->head->iov_len;
896
897 WARN_ON_ONCE(len > buf->page_len);
898 if (buf->head->iov_len >= buf->len || len > buflen)
899 buflen = len;
900 if (buf->page_len > buflen) {
901 buf->buflen -= buf->page_len - buflen;
902 buf->page_len = buflen;
903 }
904 if (len >= buf->page_len)
905 return 0;
906 shift = buf->page_len - len;
907 xdr_buf_try_expand(buf, shift);
908 xdr_buf_pages_shift_right(buf, len, buflen - len, shift);
909 buf->page_len = len;
910 buf->len -= shift;
911 buf->buflen -= shift;
912 return shift;
913 }
914
915 /**
916 * xdr_stream_pos - Return the current offset from the start of the xdr_stream
917 * @xdr: pointer to struct xdr_stream
918 */
919 unsigned int xdr_stream_pos(const struct xdr_stream *xdr)
920 {
921 return (unsigned int)(XDR_QUADLEN(xdr->buf->len) - xdr->nwords) << 2;
922 }
923 EXPORT_SYMBOL_GPL(xdr_stream_pos);
924
925 static void xdr_stream_set_pos(struct xdr_stream *xdr, unsigned int pos)
926 {
927 unsigned int blen = xdr->buf->len;
928
929 xdr->nwords = blen > pos ? XDR_QUADLEN(blen) - XDR_QUADLEN(pos) : 0;
930 }
931
932 static void xdr_stream_page_set_pos(struct xdr_stream *xdr, unsigned int pos)
933 {
934 xdr_stream_set_pos(xdr, pos + xdr->buf->head[0].iov_len);
935 }
936
937 /**
938 * xdr_page_pos - Return the current offset from the start of the xdr pages
939 * @xdr: pointer to struct xdr_stream
940 */
941 unsigned int xdr_page_pos(const struct xdr_stream *xdr)
942 {
943 unsigned int pos = xdr_stream_pos(xdr);
944
945 WARN_ON(pos < xdr->buf->head[0].iov_len);
946 return pos - xdr->buf->head[0].iov_len;
947 }
948 EXPORT_SYMBOL_GPL(xdr_page_pos);
949
950 /**
951 * xdr_init_encode - Initialize a struct xdr_stream for sending data.
952 * @xdr: pointer to xdr_stream struct
953 * @buf: pointer to XDR buffer in which to encode data
954 * @p: current pointer inside XDR buffer
955 * @rqst: pointer to controlling rpc_rqst, for debugging
956 *
957 * Note: at the moment the RPC client only passes the length of our
958 * scratch buffer in the xdr_buf's header kvec. Previously this
959 * meant we needed to call xdr_adjust_iovec() after encoding the
960 * data. With the new scheme, the xdr_stream manages the details
961 * of the buffer length, and takes care of adjusting the kvec
962 * length for us.
963 */
964 void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
965 struct rpc_rqst *rqst)
966 {
967 struct kvec *iov = buf->head;
968 int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len;
969
970 xdr_reset_scratch_buffer(xdr);
971 BUG_ON(scratch_len < 0);
972 xdr->buf = buf;
973 xdr->iov = iov;
974 xdr->p = (__be32 *)((char *)iov->iov_base + iov->iov_len);
975 xdr->end = (__be32 *)((char *)iov->iov_base + scratch_len);
976 BUG_ON(iov->iov_len > scratch_len);
977
978 if (p != xdr->p && p != NULL) {
979 size_t len;
980
981 BUG_ON(p < xdr->p || p > xdr->end);
982 len = (char *)p - (char *)xdr->p;
983 xdr->p = p;
984 buf->len += len;
985 iov->iov_len += len;
986 }
987 xdr->rqst = rqst;
988 }
989 EXPORT_SYMBOL_GPL(xdr_init_encode);
990
991 /**
992 * xdr_init_encode_pages - Initialize an xdr_stream for encoding into pages
993 * @xdr: pointer to xdr_stream struct
994 * @buf: pointer to XDR buffer into which to encode data
995 * @pages: list of pages to decode into
996 * @rqst: pointer to controlling rpc_rqst, for debugging
997 *
998 */
999 void xdr_init_encode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
1000 struct page **pages, struct rpc_rqst *rqst)
1001 {
1002 xdr_reset_scratch_buffer(xdr);
1003
1004 xdr->buf = buf;
1005 xdr->page_ptr = pages;
1006 xdr->iov = NULL;
1007 xdr->p = page_address(*pages);
1008 xdr->end = (void *)xdr->p + min_t(u32, buf->buflen, PAGE_SIZE);
1009 xdr->rqst = rqst;
1010 }
1011 EXPORT_SYMBOL_GPL(xdr_init_encode_pages);
1012
1013 /**
1014 * __xdr_commit_encode - Ensure all data is written to buffer
1015 * @xdr: pointer to xdr_stream
1016 *
1017 * We handle encoding across page boundaries by giving the caller a
1018 * temporary location to write to, then later copying the data into
1019 * place; xdr_commit_encode does that copying.
1020 *
1021 * Normally the caller doesn't need to call this directly, as the
1022 * following xdr_reserve_space will do it. But an explicit call may be
1023 * required at the end of encoding, or any other time when the xdr_buf
1024 * data might be read.
1025 */
1026 void __xdr_commit_encode(struct xdr_stream *xdr)
1027 {
1028 size_t shift = xdr->scratch.iov_len;
1029 void *page;
1030
1031 page = page_address(*xdr->page_ptr);
1032 memcpy(xdr->scratch.iov_base, page, shift);
1033 memmove(page, page + shift, (void *)xdr->p - page);
1034 xdr_reset_scratch_buffer(xdr);
1035 }
1036 EXPORT_SYMBOL_GPL(__xdr_commit_encode);
1037
1038 /*
1039 * The buffer space to be reserved crosses the boundary between
1040 * xdr->buf->head and xdr->buf->pages, or between two pages
1041 * in xdr->buf->pages.
1042 */
1043 static noinline __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr,
1044 size_t nbytes)
1045 {
1046 int space_left;
1047 int frag1bytes, frag2bytes;
1048 void *p;
1049
1050 if (nbytes > PAGE_SIZE)
1051 goto out_overflow; /* Bigger buffers require special handling */
1052 if (xdr->buf->len + nbytes > xdr->buf->buflen)
1053 goto out_overflow; /* Sorry, we're totally out of space */
1054 frag1bytes = (xdr->end - xdr->p) << 2;
1055 frag2bytes = nbytes - frag1bytes;
1056 if (xdr->iov)
1057 xdr->iov->iov_len += frag1bytes;
1058 else
1059 xdr->buf->page_len += frag1bytes;
1060 xdr->page_ptr++;
1061 xdr->iov = NULL;
1062
1063 /*
1064 * If the last encode didn't end exactly on a page boundary, the
1065 * next one will straddle boundaries. Encode into the next
1066 * page, then copy it back later in xdr_commit_encode. We use
1067 * the "scratch" iov to track any temporarily unused fragment of
1068 * space at the end of the previous buffer:
1069 */
1070 xdr_set_scratch_buffer(xdr, xdr->p, frag1bytes);
1071
1072 /*
1073 * xdr->p is where the next encode will start after
1074 * xdr_commit_encode() has shifted this one back:
1075 */
1076 p = page_address(*xdr->page_ptr);
1077 xdr->p = p + frag2bytes;
1078 space_left = xdr->buf->buflen - xdr->buf->len;
1079 if (space_left - frag1bytes >= PAGE_SIZE)
1080 xdr->end = p + PAGE_SIZE;
1081 else
1082 xdr->end = p + space_left - frag1bytes;
1083
1084 xdr->buf->page_len += frag2bytes;
1085 xdr->buf->len += nbytes;
1086 return p;
1087 out_overflow:
1088 trace_rpc_xdr_overflow(xdr, nbytes);
1089 return NULL;
1090 }
1091
1092 /**
1093 * xdr_reserve_space - Reserve buffer space for sending
1094 * @xdr: pointer to xdr_stream
1095 * @nbytes: number of bytes to reserve
1096 *
1097 * Checks that we have enough buffer space to encode 'nbytes' more
1098 * bytes of data. If so, update the total xdr_buf length, and
1099 * adjust the length of the current kvec.
1100 */
1101 __be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
1102 {
1103 __be32 *p = xdr->p;
1104 __be32 *q;
1105
1106 xdr_commit_encode(xdr);
1107 /* align nbytes on the next 32-bit boundary */
1108 nbytes += 3;
1109 nbytes &= ~3;
1110 q = p + (nbytes >> 2);
1111 if (unlikely(q > xdr->end || q < p))
1112 return xdr_get_next_encode_buffer(xdr, nbytes);
1113 xdr->p = q;
1114 if (xdr->iov)
1115 xdr->iov->iov_len += nbytes;
1116 else
1117 xdr->buf->page_len += nbytes;
1118 xdr->buf->len += nbytes;
1119 return p;
1120 }
1121 EXPORT_SYMBOL_GPL(xdr_reserve_space);
1122
1123 /**
1124 * xdr_reserve_space_vec - Reserves a large amount of buffer space for sending
1125 * @xdr: pointer to xdr_stream
1126 * @nbytes: number of bytes to reserve
1127 *
1128 * The size argument passed to xdr_reserve_space() is determined based
1129 * on the number of bytes remaining in the current page to avoid
1130 * invalidating iov_base pointers when xdr_commit_encode() is called.
1131 *
1132 * Return values:
1133 * %0: success
1134 * %-EMSGSIZE: not enough space is available in @xdr
1135 */
1136 int xdr_reserve_space_vec(struct xdr_stream *xdr, size_t nbytes)
1137 {
1138 size_t thislen;
1139 __be32 *p;
1140
1141 /*
1142 * svcrdma requires every READ payload to start somewhere
1143 * in xdr->pages.
1144 */
1145 if (xdr->iov == xdr->buf->head) {
1146 xdr->iov = NULL;
1147 xdr->end = xdr->p;
1148 }
1149
1150 /* XXX: Let's find a way to make this more efficient */
1151 while (nbytes) {
1152 thislen = xdr->buf->page_len % PAGE_SIZE;
1153 thislen = min_t(size_t, nbytes, PAGE_SIZE - thislen);
1154
1155 p = xdr_reserve_space(xdr, thislen);
1156 if (!p)
1157 return -EMSGSIZE;
1158
1159 nbytes -= thislen;
1160 }
1161
1162 return 0;
1163 }
1164 EXPORT_SYMBOL_GPL(xdr_reserve_space_vec);
1165
1166 /**
1167 * xdr_truncate_encode - truncate an encode buffer
1168 * @xdr: pointer to xdr_stream
1169 * @len: new length of buffer
1170 *
1171 * Truncates the xdr stream, so that xdr->buf->len == len,
1172 * and xdr->p points at offset len from the start of the buffer, and
1173 * head, tail, and page lengths are adjusted to correspond.
1174 *
1175 * If this means moving xdr->p to a different buffer, we assume that
1176 * the end pointer should be set to the end of the current page,
1177 * except in the case of the head buffer when we assume the head
1178 * buffer's current length represents the end of the available buffer.
1179 *
1180 * This is *not* safe to use on a buffer that already has inlined page
1181 * cache pages (as in a zero-copy server read reply), except for the
1182 * simple case of truncating from one position in the tail to another.
1183 *
1184 */
1185 void xdr_truncate_encode(struct xdr_stream *xdr, size_t len)
1186 {
1187 struct xdr_buf *buf = xdr->buf;
1188 struct kvec *head = buf->head;
1189 struct kvec *tail = buf->tail;
1190 int fraglen;
1191 int new;
1192
1193 if (len > buf->len) {
1194 WARN_ON_ONCE(1);
1195 return;
1196 }
1197 xdr_commit_encode(xdr);
1198
1199 fraglen = min_t(int, buf->len - len, tail->iov_len);
1200 tail->iov_len -= fraglen;
1201 buf->len -= fraglen;
1202 if (tail->iov_len) {
1203 xdr->p = tail->iov_base + tail->iov_len;
1204 WARN_ON_ONCE(!xdr->end);
1205 WARN_ON_ONCE(!xdr->iov);
1206 return;
1207 }
1208 WARN_ON_ONCE(fraglen);
1209 fraglen = min_t(int, buf->len - len, buf->page_len);
1210 buf->page_len -= fraglen;
1211 buf->len -= fraglen;
1212
1213 new = buf->page_base + buf->page_len;
1214
1215 xdr->page_ptr = buf->pages + (new >> PAGE_SHIFT);
1216
1217 if (buf->page_len) {
1218 xdr->p = page_address(*xdr->page_ptr);
1219 xdr->end = (void *)xdr->p + PAGE_SIZE;
1220 xdr->p = (void *)xdr->p + (new % PAGE_SIZE);
1221 WARN_ON_ONCE(xdr->iov);
1222 return;
1223 }
1224 if (fraglen)
1225 xdr->end = head->iov_base + head->iov_len;
1226 /* (otherwise assume xdr->end is already set) */
1227 xdr->page_ptr--;
1228 head->iov_len = len;
1229 buf->len = len;
1230 xdr->p = head->iov_base + head->iov_len;
1231 xdr->iov = buf->head;
1232 }
1233 EXPORT_SYMBOL(xdr_truncate_encode);
1234
1235 /**
1236 * xdr_truncate_decode - Truncate a decoding stream
1237 * @xdr: pointer to struct xdr_stream
1238 * @len: Number of bytes to remove
1239 *
1240 */
1241 void xdr_truncate_decode(struct xdr_stream *xdr, size_t len)
1242 {
1243 unsigned int nbytes = xdr_align_size(len);
1244
1245 xdr->buf->len -= nbytes;
1246 xdr->nwords -= XDR_QUADLEN(nbytes);
1247 }
1248 EXPORT_SYMBOL_GPL(xdr_truncate_decode);
1249
1250 /**
1251 * xdr_restrict_buflen - decrease available buffer space
1252 * @xdr: pointer to xdr_stream
1253 * @newbuflen: new maximum number of bytes available
1254 *
1255 * Adjust our idea of how much space is available in the buffer.
1256 * If we've already used too much space in the buffer, returns -1.
1257 * If the available space is already smaller than newbuflen, returns 0
1258 * and does nothing. Otherwise, adjusts xdr->buf->buflen to newbuflen
1259 * and ensures xdr->end is set at most offset newbuflen from the start
1260 * of the buffer.
1261 */
1262 int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen)
1263 {
1264 struct xdr_buf *buf = xdr->buf;
1265 int left_in_this_buf = (void *)xdr->end - (void *)xdr->p;
1266 int end_offset = buf->len + left_in_this_buf;
1267
1268 if (newbuflen < 0 || newbuflen < buf->len)
1269 return -1;
1270 if (newbuflen > buf->buflen)
1271 return 0;
1272 if (newbuflen < end_offset)
1273 xdr->end = (void *)xdr->end + newbuflen - end_offset;
1274 buf->buflen = newbuflen;
1275 return 0;
1276 }
1277 EXPORT_SYMBOL(xdr_restrict_buflen);
1278
1279 /**
1280 * xdr_write_pages - Insert a list of pages into an XDR buffer for sending
1281 * @xdr: pointer to xdr_stream
1282 * @pages: array of pages to insert
1283 * @base: starting offset of first data byte in @pages
1284 * @len: number of data bytes in @pages to insert
1285 *
1286 * After the @pages are added, the tail iovec is instantiated pointing to
1287 * end of the head buffer, and the stream is set up to encode subsequent
1288 * items into the tail.
1289 */
1290 void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base,
1291 unsigned int len)
1292 {
1293 struct xdr_buf *buf = xdr->buf;
1294 struct kvec *tail = buf->tail;
1295
1296 buf->pages = pages;
1297 buf->page_base = base;
1298 buf->page_len = len;
1299
1300 tail->iov_base = xdr->p;
1301 tail->iov_len = 0;
1302 xdr->iov = tail;
1303
1304 if (len & 3) {
1305 unsigned int pad = 4 - (len & 3);
1306
1307 BUG_ON(xdr->p >= xdr->end);
1308 tail->iov_base = (char *)xdr->p + (len & 3);
1309 tail->iov_len += pad;
1310 len += pad;
1311 *xdr->p++ = 0;
1312 }
1313 buf->buflen += len;
1314 buf->len += len;
1315 }
1316 EXPORT_SYMBOL_GPL(xdr_write_pages);
1317
1318 static unsigned int xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
1319 unsigned int base, unsigned int len)
1320 {
1321 if (len > iov->iov_len)
1322 len = iov->iov_len;
1323 if (unlikely(base > len))
1324 base = len;
1325 xdr->p = (__be32*)(iov->iov_base + base);
1326 xdr->end = (__be32*)(iov->iov_base + len);
1327 xdr->iov = iov;
1328 xdr->page_ptr = NULL;
1329 return len - base;
1330 }
1331
1332 static unsigned int xdr_set_tail_base(struct xdr_stream *xdr,
1333 unsigned int base, unsigned int len)
1334 {
1335 struct xdr_buf *buf = xdr->buf;
1336
1337 xdr_stream_set_pos(xdr, base + buf->page_len + buf->head->iov_len);
1338 return xdr_set_iov(xdr, buf->tail, base, len);
1339 }
1340
1341 static void xdr_stream_unmap_current_page(struct xdr_stream *xdr)
1342 {
1343 if (xdr->page_kaddr) {
1344 kunmap_local(xdr->page_kaddr);
1345 xdr->page_kaddr = NULL;
1346 }
1347 }
1348
1349 static unsigned int xdr_set_page_base(struct xdr_stream *xdr,
1350 unsigned int base, unsigned int len)
1351 {
1352 unsigned int pgnr;
1353 unsigned int maxlen;
1354 unsigned int pgoff;
1355 unsigned int pgend;
1356 void *kaddr;
1357
1358 maxlen = xdr->buf->page_len;
1359 if (base >= maxlen)
1360 return 0;
1361 else
1362 maxlen -= base;
1363 if (len > maxlen)
1364 len = maxlen;
1365
1366 xdr_stream_unmap_current_page(xdr);
1367 xdr_stream_page_set_pos(xdr, base);
1368 base += xdr->buf->page_base;
1369
1370 pgnr = base >> PAGE_SHIFT;
1371 xdr->page_ptr = &xdr->buf->pages[pgnr];
1372
1373 if (PageHighMem(*xdr->page_ptr)) {
1374 xdr->page_kaddr = kmap_local_page(*xdr->page_ptr);
1375 kaddr = xdr->page_kaddr;
1376 } else
1377 kaddr = page_address(*xdr->page_ptr);
1378
1379 pgoff = base & ~PAGE_MASK;
1380 xdr->p = (__be32*)(kaddr + pgoff);
1381
1382 pgend = pgoff + len;
1383 if (pgend > PAGE_SIZE)
1384 pgend = PAGE_SIZE;
1385 xdr->end = (__be32*)(kaddr + pgend);
1386 xdr->iov = NULL;
1387 return len;
1388 }
1389
1390 static void xdr_set_page(struct xdr_stream *xdr, unsigned int base,
1391 unsigned int len)
1392 {
1393 if (xdr_set_page_base(xdr, base, len) == 0) {
1394 base -= xdr->buf->page_len;
1395 xdr_set_tail_base(xdr, base, len);
1396 }
1397 }
1398
1399 static void xdr_set_next_page(struct xdr_stream *xdr)
1400 {
1401 unsigned int newbase;
1402
1403 newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT;
1404 newbase -= xdr->buf->page_base;
1405 if (newbase < xdr->buf->page_len)
1406 xdr_set_page_base(xdr, newbase, xdr_stream_remaining(xdr));
1407 else
1408 xdr_set_tail_base(xdr, 0, xdr_stream_remaining(xdr));
1409 }
1410
1411 static bool xdr_set_next_buffer(struct xdr_stream *xdr)
1412 {
1413 if (xdr->page_ptr != NULL)
1414 xdr_set_next_page(xdr);
1415 else if (xdr->iov == xdr->buf->head)
1416 xdr_set_page(xdr, 0, xdr_stream_remaining(xdr));
1417 return xdr->p != xdr->end;
1418 }
1419
1420 /**
1421 * xdr_init_decode - Initialize an xdr_stream for decoding data.
1422 * @xdr: pointer to xdr_stream struct
1423 * @buf: pointer to XDR buffer from which to decode data
1424 * @p: current pointer inside XDR buffer
1425 * @rqst: pointer to controlling rpc_rqst, for debugging
1426 */
1427 void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
1428 struct rpc_rqst *rqst)
1429 {
1430 xdr->buf = buf;
1431 xdr->page_kaddr = NULL;
1432 xdr_reset_scratch_buffer(xdr);
1433 xdr->nwords = XDR_QUADLEN(buf->len);
1434 if (xdr_set_iov(xdr, buf->head, 0, buf->len) == 0 &&
1435 xdr_set_page_base(xdr, 0, buf->len) == 0)
1436 xdr_set_iov(xdr, buf->tail, 0, buf->len);
1437 if (p != NULL && p > xdr->p && xdr->end >= p) {
1438 xdr->nwords -= p - xdr->p;
1439 xdr->p = p;
1440 }
1441 xdr->rqst = rqst;
1442 }
1443 EXPORT_SYMBOL_GPL(xdr_init_decode);
1444
1445 /**
1446 * xdr_init_decode_pages - Initialize an xdr_stream for decoding into pages
1447 * @xdr: pointer to xdr_stream struct
1448 * @buf: pointer to XDR buffer from which to decode data
1449 * @pages: list of pages to decode into
1450 * @len: length in bytes of buffer in pages
1451 */
1452 void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
1453 struct page **pages, unsigned int len)
1454 {
1455 memset(buf, 0, sizeof(*buf));
1456 buf->pages = pages;
1457 buf->page_len = len;
1458 buf->buflen = len;
1459 buf->len = len;
1460 xdr_init_decode(xdr, buf, NULL, NULL);
1461 }
1462 EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
1463
1464 /**
1465 * xdr_finish_decode - Clean up the xdr_stream after decoding data.
1466 * @xdr: pointer to xdr_stream struct
1467 */
1468 void xdr_finish_decode(struct xdr_stream *xdr)
1469 {
1470 xdr_stream_unmap_current_page(xdr);
1471 }
1472 EXPORT_SYMBOL(xdr_finish_decode);
1473
1474 static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
1475 {
1476 unsigned int nwords = XDR_QUADLEN(nbytes);
1477 __be32 *p = xdr->p;
1478 __be32 *q = p + nwords;
1479
1480 if (unlikely(nwords > xdr->nwords || q > xdr->end || q < p))
1481 return NULL;
1482 xdr->p = q;
1483 xdr->nwords -= nwords;
1484 return p;
1485 }
1486
1487 static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes)
1488 {
1489 __be32 *p;
1490 char *cpdest = xdr->scratch.iov_base;
1491 size_t cplen = (char *)xdr->end - (char *)xdr->p;
1492
1493 if (nbytes > xdr->scratch.iov_len)
1494 goto out_overflow;
1495 p = __xdr_inline_decode(xdr, cplen);
1496 if (p == NULL)
1497 return NULL;
1498 memcpy(cpdest, p, cplen);
1499 if (!xdr_set_next_buffer(xdr))
1500 goto out_overflow;
1501 cpdest += cplen;
1502 nbytes -= cplen;
1503 p = __xdr_inline_decode(xdr, nbytes);
1504 if (p == NULL)
1505 return NULL;
1506 memcpy(cpdest, p, nbytes);
1507 return xdr->scratch.iov_base;
1508 out_overflow:
1509 trace_rpc_xdr_overflow(xdr, nbytes);
1510 return NULL;
1511 }
1512
1513 /**
1514 * xdr_inline_decode - Retrieve XDR data to decode
1515 * @xdr: pointer to xdr_stream struct
1516 * @nbytes: number of bytes of data to decode
1517 *
1518 * Check if the input buffer is long enough to enable us to decode
1519 * 'nbytes' more bytes of data starting at the current position.
1520 * If so return the current pointer, then update the current
1521 * pointer position.
1522 */
1523 __be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
1524 {
1525 __be32 *p;
1526
1527 if (unlikely(nbytes == 0))
1528 return xdr->p;
1529 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
1530 goto out_overflow;
1531 p = __xdr_inline_decode(xdr, nbytes);
1532 if (p != NULL)
1533 return p;
1534 return xdr_copy_to_scratch(xdr, nbytes);
1535 out_overflow:
1536 trace_rpc_xdr_overflow(xdr, nbytes);
1537 return NULL;
1538 }
1539 EXPORT_SYMBOL_GPL(xdr_inline_decode);
1540
1541 static void xdr_realign_pages(struct xdr_stream *xdr)
1542 {
1543 struct xdr_buf *buf = xdr->buf;
1544 struct kvec *iov = buf->head;
1545 unsigned int cur = xdr_stream_pos(xdr);
1546 unsigned int copied;
1547
1548 /* Realign pages to current pointer position */
1549 if (iov->iov_len > cur) {
1550 copied = xdr_shrink_bufhead(buf, cur);
1551 trace_rpc_xdr_alignment(xdr, cur, copied);
1552 xdr_set_page(xdr, 0, buf->page_len);
1553 }
1554 }
1555
1556 static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len)
1557 {
1558 struct xdr_buf *buf = xdr->buf;
1559 unsigned int nwords = XDR_QUADLEN(len);
1560 unsigned int copied;
1561
1562 if (xdr->nwords == 0)
1563 return 0;
1564
1565 xdr_realign_pages(xdr);
1566 if (nwords > xdr->nwords) {
1567 nwords = xdr->nwords;
1568 len = nwords << 2;
1569 }
1570 if (buf->page_len <= len)
1571 len = buf->page_len;
1572 else if (nwords < xdr->nwords) {
1573 /* Truncate page data and move it into the tail */
1574 copied = xdr_shrink_pagelen(buf, len);
1575 trace_rpc_xdr_alignment(xdr, len, copied);
1576 }
1577 return len;
1578 }
1579
1580 /**
1581 * xdr_read_pages - align page-based XDR data to current pointer position
1582 * @xdr: pointer to xdr_stream struct
1583 * @len: number of bytes of page data
1584 *
1585 * Moves data beyond the current pointer position from the XDR head[] buffer
1586 * into the page list. Any data that lies beyond current position + @len
1587 * bytes is moved into the XDR tail[]. The xdr_stream current position is
1588 * then advanced past that data to align to the next XDR object in the tail.
1589 *
1590 * Returns the number of XDR encoded bytes now contained in the pages
1591 */
1592 unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
1593 {
1594 unsigned int nwords = XDR_QUADLEN(len);
1595 unsigned int base, end, pglen;
1596
1597 pglen = xdr_align_pages(xdr, nwords << 2);
1598 if (pglen == 0)
1599 return 0;
1600
1601 base = (nwords << 2) - pglen;
1602 end = xdr_stream_remaining(xdr) - pglen;
1603
1604 xdr_set_tail_base(xdr, base, end);
1605 return len <= pglen ? len : pglen;
1606 }
1607 EXPORT_SYMBOL_GPL(xdr_read_pages);
1608
1609 /**
1610 * xdr_set_pagelen - Sets the length of the XDR pages
1611 * @xdr: pointer to xdr_stream struct
1612 * @len: new length of the XDR page data
1613 *
1614 * Either grows or shrinks the length of the xdr pages by setting pagelen to
1615 * @len bytes. When shrinking, any extra data is moved into buf->tail, whereas
1616 * when growing any data beyond the current pointer is moved into the tail.
1617 *
1618 * Returns True if the operation was successful, and False otherwise.
1619 */
1620 void xdr_set_pagelen(struct xdr_stream *xdr, unsigned int len)
1621 {
1622 struct xdr_buf *buf = xdr->buf;
1623 size_t remaining = xdr_stream_remaining(xdr);
1624 size_t base = 0;
1625
1626 if (len < buf->page_len) {
1627 base = buf->page_len - len;
1628 xdr_shrink_pagelen(buf, len);
1629 } else {
1630 xdr_buf_head_shift_right(buf, xdr_stream_pos(xdr),
1631 buf->page_len, remaining);
1632 if (len > buf->page_len)
1633 xdr_buf_try_expand(buf, len - buf->page_len);
1634 }
1635 xdr_set_tail_base(xdr, base, remaining);
1636 }
1637 EXPORT_SYMBOL_GPL(xdr_set_pagelen);
1638
1639 /**
1640 * xdr_enter_page - decode data from the XDR page
1641 * @xdr: pointer to xdr_stream struct
1642 * @len: number of bytes of page data
1643 *
1644 * Moves data beyond the current pointer position from the XDR head[] buffer
1645 * into the page list. Any data that lies beyond current position + "len"
1646 * bytes is moved into the XDR tail[]. The current pointer is then
1647 * repositioned at the beginning of the first XDR page.
1648 */
1649 void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
1650 {
1651 len = xdr_align_pages(xdr, len);
1652 /*
1653 * Position current pointer at beginning of tail, and
1654 * set remaining message length.
1655 */
1656 if (len != 0)
1657 xdr_set_page_base(xdr, 0, len);
1658 }
1659 EXPORT_SYMBOL_GPL(xdr_enter_page);
1660
1661 static const struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0};
1662
1663 void xdr_buf_from_iov(const struct kvec *iov, struct xdr_buf *buf)
1664 {
1665 buf->head[0] = *iov;
1666 buf->tail[0] = empty_iov;
1667 buf->page_len = 0;
1668 buf->buflen = buf->len = iov->iov_len;
1669 }
1670 EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
1671
1672 /**
1673 * xdr_buf_subsegment - set subbuf to a portion of buf
1674 * @buf: an xdr buffer
1675 * @subbuf: the result buffer
1676 * @base: beginning of range in bytes
1677 * @len: length of range in bytes
1678 *
1679 * sets @subbuf to an xdr buffer representing the portion of @buf of
1680 * length @len starting at offset @base.
1681 *
1682 * @buf and @subbuf may be pointers to the same struct xdr_buf.
1683 *
1684 * Returns -1 if base or length are out of bounds.
1685 */
1686 int xdr_buf_subsegment(const struct xdr_buf *buf, struct xdr_buf *subbuf,
1687 unsigned int base, unsigned int len)
1688 {
1689 subbuf->buflen = subbuf->len = len;
1690 if (base < buf->head[0].iov_len) {
1691 subbuf->head[0].iov_base = buf->head[0].iov_base + base;
1692 subbuf->head[0].iov_len = min_t(unsigned int, len,
1693 buf->head[0].iov_len - base);
1694 len -= subbuf->head[0].iov_len;
1695 base = 0;
1696 } else {
1697 base -= buf->head[0].iov_len;
1698 subbuf->head[0].iov_base = buf->head[0].iov_base;
1699 subbuf->head[0].iov_len = 0;
1700 }
1701
1702 if (base < buf->page_len) {
1703 subbuf->page_len = min(buf->page_len - base, len);
1704 base += buf->page_base;
1705 subbuf->page_base = base & ~PAGE_MASK;
1706 subbuf->pages = &buf->pages[base >> PAGE_SHIFT];
1707 len -= subbuf->page_len;
1708 base = 0;
1709 } else {
1710 base -= buf->page_len;
1711 subbuf->pages = buf->pages;
1712 subbuf->page_base = 0;
1713 subbuf->page_len = 0;
1714 }
1715
1716 if (base < buf->tail[0].iov_len) {
1717 subbuf->tail[0].iov_base = buf->tail[0].iov_base + base;
1718 subbuf->tail[0].iov_len = min_t(unsigned int, len,
1719 buf->tail[0].iov_len - base);
1720 len -= subbuf->tail[0].iov_len;
1721 base = 0;
1722 } else {
1723 base -= buf->tail[0].iov_len;
1724 subbuf->tail[0].iov_base = buf->tail[0].iov_base;
1725 subbuf->tail[0].iov_len = 0;
1726 }
1727
1728 if (base || len)
1729 return -1;
1730 return 0;
1731 }
1732 EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
1733
1734 /**
1735 * xdr_stream_subsegment - set @subbuf to a portion of @xdr
1736 * @xdr: an xdr_stream set up for decoding
1737 * @subbuf: the result buffer
1738 * @nbytes: length of @xdr to extract, in bytes
1739 *
1740 * Sets up @subbuf to represent a portion of @xdr. The portion
1741 * starts at the current offset in @xdr, and extends for a length
1742 * of @nbytes. If this is successful, @xdr is advanced to the next
1743 * XDR data item following that portion.
1744 *
1745 * Return values:
1746 * %true: @subbuf has been initialized, and @xdr has been advanced.
1747 * %false: a bounds error has occurred
1748 */
1749 bool xdr_stream_subsegment(struct xdr_stream *xdr, struct xdr_buf *subbuf,
1750 unsigned int nbytes)
1751 {
1752 unsigned int start = xdr_stream_pos(xdr);
1753 unsigned int remaining, len;
1754
1755 /* Extract @subbuf and bounds-check the fn arguments */
1756 if (xdr_buf_subsegment(xdr->buf, subbuf, start, nbytes))
1757 return false;
1758
1759 /* Advance @xdr by @nbytes */
1760 for (remaining = nbytes; remaining;) {
1761 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
1762 return false;
1763
1764 len = (char *)xdr->end - (char *)xdr->p;
1765 if (remaining <= len) {
1766 xdr->p = (__be32 *)((char *)xdr->p +
1767 (remaining + xdr_pad_size(nbytes)));
1768 break;
1769 }
1770
1771 xdr->p = (__be32 *)((char *)xdr->p + len);
1772 xdr->end = xdr->p;
1773 remaining -= len;
1774 }
1775
1776 xdr_stream_set_pos(xdr, start + nbytes);
1777 return true;
1778 }
1779 EXPORT_SYMBOL_GPL(xdr_stream_subsegment);
1780
1781 /**
1782 * xdr_stream_move_subsegment - Move part of a stream to another position
1783 * @xdr: the source xdr_stream
1784 * @offset: the source offset of the segment
1785 * @target: the target offset of the segment
1786 * @length: the number of bytes to move
1787 *
1788 * Moves @length bytes from @offset to @target in the xdr_stream, overwriting
1789 * anything in its space. Returns the number of bytes in the segment.
1790 */
1791 unsigned int xdr_stream_move_subsegment(struct xdr_stream *xdr, unsigned int offset,
1792 unsigned int target, unsigned int length)
1793 {
1794 struct xdr_buf buf;
1795 unsigned int shift;
1796
1797 if (offset < target) {
1798 shift = target - offset;
1799 if (xdr_buf_subsegment(xdr->buf, &buf, offset, shift + length) < 0)
1800 return 0;
1801 xdr_buf_head_shift_right(&buf, 0, length, shift);
1802 } else if (offset > target) {
1803 shift = offset - target;
1804 if (xdr_buf_subsegment(xdr->buf, &buf, target, shift + length) < 0)
1805 return 0;
1806 xdr_buf_head_shift_left(&buf, shift, length, shift);
1807 }
1808 return length;
1809 }
1810 EXPORT_SYMBOL_GPL(xdr_stream_move_subsegment);
1811
1812 /**
1813 * xdr_stream_zero - zero out a portion of an xdr_stream
1814 * @xdr: an xdr_stream to zero out
1815 * @offset: the starting point in the stream
1816 * @length: the number of bytes to zero
1817 */
1818 unsigned int xdr_stream_zero(struct xdr_stream *xdr, unsigned int offset,
1819 unsigned int length)
1820 {
1821 struct xdr_buf buf;
1822
1823 if (xdr_buf_subsegment(xdr->buf, &buf, offset, length) < 0)
1824 return 0;
1825 if (buf.head[0].iov_len)
1826 xdr_buf_iov_zero(buf.head, 0, buf.head[0].iov_len);
1827 if (buf.page_len > 0)
1828 xdr_buf_pages_zero(&buf, 0, buf.page_len);
1829 if (buf.tail[0].iov_len)
1830 xdr_buf_iov_zero(buf.tail, 0, buf.tail[0].iov_len);
1831 return length;
1832 }
1833 EXPORT_SYMBOL_GPL(xdr_stream_zero);
1834
1835 /**
1836 * xdr_buf_trim - lop at most "len" bytes off the end of "buf"
1837 * @buf: buf to be trimmed
1838 * @len: number of bytes to reduce "buf" by
1839 *
1840 * Trim an xdr_buf by the given number of bytes by fixing up the lengths. Note
1841 * that it's possible that we'll trim less than that amount if the xdr_buf is
1842 * too small, or if (for instance) it's all in the head and the parser has
1843 * already read too far into it.
1844 */
1845 void xdr_buf_trim(struct xdr_buf *buf, unsigned int len)
1846 {
1847 size_t cur;
1848 unsigned int trim = len;
1849
1850 if (buf->tail[0].iov_len) {
1851 cur = min_t(size_t, buf->tail[0].iov_len, trim);
1852 buf->tail[0].iov_len -= cur;
1853 trim -= cur;
1854 if (!trim)
1855 goto fix_len;
1856 }
1857
1858 if (buf->page_len) {
1859 cur = min_t(unsigned int, buf->page_len, trim);
1860 buf->page_len -= cur;
1861 trim -= cur;
1862 if (!trim)
1863 goto fix_len;
1864 }
1865
1866 if (buf->head[0].iov_len) {
1867 cur = min_t(size_t, buf->head[0].iov_len, trim);
1868 buf->head[0].iov_len -= cur;
1869 trim -= cur;
1870 }
1871 fix_len:
1872 buf->len -= (len - trim);
1873 }
1874 EXPORT_SYMBOL_GPL(xdr_buf_trim);
1875
1876 static void __read_bytes_from_xdr_buf(const struct xdr_buf *subbuf,
1877 void *obj, unsigned int len)
1878 {
1879 unsigned int this_len;
1880
1881 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1882 memcpy(obj, subbuf->head[0].iov_base, this_len);
1883 len -= this_len;
1884 obj += this_len;
1885 this_len = min_t(unsigned int, len, subbuf->page_len);
1886 _copy_from_pages(obj, subbuf->pages, subbuf->page_base, this_len);
1887 len -= this_len;
1888 obj += this_len;
1889 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1890 memcpy(obj, subbuf->tail[0].iov_base, this_len);
1891 }
1892
1893 /* obj is assumed to point to allocated memory of size at least len: */
1894 int read_bytes_from_xdr_buf(const struct xdr_buf *buf, unsigned int base,
1895 void *obj, unsigned int len)
1896 {
1897 struct xdr_buf subbuf;
1898 int status;
1899
1900 status = xdr_buf_subsegment(buf, &subbuf, base, len);
1901 if (status != 0)
1902 return status;
1903 __read_bytes_from_xdr_buf(&subbuf, obj, len);
1904 return 0;
1905 }
1906 EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf);
1907
1908 static void __write_bytes_to_xdr_buf(const struct xdr_buf *subbuf,
1909 void *obj, unsigned int len)
1910 {
1911 unsigned int this_len;
1912
1913 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1914 memcpy(subbuf->head[0].iov_base, obj, this_len);
1915 len -= this_len;
1916 obj += this_len;
1917 this_len = min_t(unsigned int, len, subbuf->page_len);
1918 _copy_to_pages(subbuf->pages, subbuf->page_base, obj, this_len);
1919 len -= this_len;
1920 obj += this_len;
1921 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1922 memcpy(subbuf->tail[0].iov_base, obj, this_len);
1923 }
1924
1925 /* obj is assumed to point to allocated memory of size at least len: */
1926 int write_bytes_to_xdr_buf(const struct xdr_buf *buf, unsigned int base,
1927 void *obj, unsigned int len)
1928 {
1929 struct xdr_buf subbuf;
1930 int status;
1931
1932 status = xdr_buf_subsegment(buf, &subbuf, base, len);
1933 if (status != 0)
1934 return status;
1935 __write_bytes_to_xdr_buf(&subbuf, obj, len);
1936 return 0;
1937 }
1938 EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf);
1939
1940 int xdr_decode_word(const struct xdr_buf *buf, unsigned int base, u32 *obj)
1941 {
1942 __be32 raw;
1943 int status;
1944
1945 status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
1946 if (status)
1947 return status;
1948 *obj = be32_to_cpu(raw);
1949 return 0;
1950 }
1951 EXPORT_SYMBOL_GPL(xdr_decode_word);
1952
1953 int xdr_encode_word(const struct xdr_buf *buf, unsigned int base, u32 obj)
1954 {
1955 __be32 raw = cpu_to_be32(obj);
1956
1957 return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj));
1958 }
1959 EXPORT_SYMBOL_GPL(xdr_encode_word);
1960
1961 /* Returns 0 on success, or else a negative error code. */
1962 static int xdr_xcode_array2(const struct xdr_buf *buf, unsigned int base,
1963 struct xdr_array2_desc *desc, int encode)
1964 {
1965 char *elem = NULL, *c;
1966 unsigned int copied = 0, todo, avail_here;
1967 struct page **ppages = NULL;
1968 int err;
1969
1970 if (encode) {
1971 if (xdr_encode_word(buf, base, desc->array_len) != 0)
1972 return -EINVAL;
1973 } else {
1974 if (xdr_decode_word(buf, base, &desc->array_len) != 0 ||
1975 desc->array_len > desc->array_maxlen ||
1976 (unsigned long) base + 4 + desc->array_len *
1977 desc->elem_size > buf->len)
1978 return -EINVAL;
1979 }
1980 base += 4;
1981
1982 if (!desc->xcode)
1983 return 0;
1984
1985 todo = desc->array_len * desc->elem_size;
1986
1987 /* process head */
1988 if (todo && base < buf->head->iov_len) {
1989 c = buf->head->iov_base + base;
1990 avail_here = min_t(unsigned int, todo,
1991 buf->head->iov_len - base);
1992 todo -= avail_here;
1993
1994 while (avail_here >= desc->elem_size) {
1995 err = desc->xcode(desc, c);
1996 if (err)
1997 goto out;
1998 c += desc->elem_size;
1999 avail_here -= desc->elem_size;
2000 }
2001 if (avail_here) {
2002 if (!elem) {
2003 elem = kmalloc(desc->elem_size, GFP_KERNEL);
2004 err = -ENOMEM;
2005 if (!elem)
2006 goto out;
2007 }
2008 if (encode) {
2009 err = desc->xcode(desc, elem);
2010 if (err)
2011 goto out;
2012 memcpy(c, elem, avail_here);
2013 } else
2014 memcpy(elem, c, avail_here);
2015 copied = avail_here;
2016 }
2017 base = buf->head->iov_len; /* align to start of pages */
2018 }
2019
2020 /* process pages array */
2021 base -= buf->head->iov_len;
2022 if (todo && base < buf->page_len) {
2023 unsigned int avail_page;
2024
2025 avail_here = min(todo, buf->page_len - base);
2026 todo -= avail_here;
2027
2028 base += buf->page_base;
2029 ppages = buf->pages + (base >> PAGE_SHIFT);
2030 base &= ~PAGE_MASK;
2031 avail_page = min_t(unsigned int, PAGE_SIZE - base,
2032 avail_here);
2033 c = kmap(*ppages) + base;
2034
2035 while (avail_here) {
2036 avail_here -= avail_page;
2037 if (copied || avail_page < desc->elem_size) {
2038 unsigned int l = min(avail_page,
2039 desc->elem_size - copied);
2040 if (!elem) {
2041 elem = kmalloc(desc->elem_size,
2042 GFP_KERNEL);
2043 err = -ENOMEM;
2044 if (!elem)
2045 goto out;
2046 }
2047 if (encode) {
2048 if (!copied) {
2049 err = desc->xcode(desc, elem);
2050 if (err)
2051 goto out;
2052 }
2053 memcpy(c, elem + copied, l);
2054 copied += l;
2055 if (copied == desc->elem_size)
2056 copied = 0;
2057 } else {
2058 memcpy(elem + copied, c, l);
2059 copied += l;
2060 if (copied == desc->elem_size) {
2061 err = desc->xcode(desc, elem);
2062 if (err)
2063 goto out;
2064 copied = 0;
2065 }
2066 }
2067 avail_page -= l;
2068 c += l;
2069 }
2070 while (avail_page >= desc->elem_size) {
2071 err = desc->xcode(desc, c);
2072 if (err)
2073 goto out;
2074 c += desc->elem_size;
2075 avail_page -= desc->elem_size;
2076 }
2077 if (avail_page) {
2078 unsigned int l = min(avail_page,
2079 desc->elem_size - copied);
2080 if (!elem) {
2081 elem = kmalloc(desc->elem_size,
2082 GFP_KERNEL);
2083 err = -ENOMEM;
2084 if (!elem)
2085 goto out;
2086 }
2087 if (encode) {
2088 if (!copied) {
2089 err = desc->xcode(desc, elem);
2090 if (err)
2091 goto out;
2092 }
2093 memcpy(c, elem + copied, l);
2094 copied += l;
2095 if (copied == desc->elem_size)
2096 copied = 0;
2097 } else {
2098 memcpy(elem + copied, c, l);
2099 copied += l;
2100 if (copied == desc->elem_size) {
2101 err = desc->xcode(desc, elem);
2102 if (err)
2103 goto out;
2104 copied = 0;
2105 }
2106 }
2107 }
2108 if (avail_here) {
2109 kunmap(*ppages);
2110 ppages++;
2111 c = kmap(*ppages);
2112 }
2113
2114 avail_page = min(avail_here,
2115 (unsigned int) PAGE_SIZE);
2116 }
2117 base = buf->page_len; /* align to start of tail */
2118 }
2119
2120 /* process tail */
2121 base -= buf->page_len;
2122 if (todo) {
2123 c = buf->tail->iov_base + base;
2124 if (copied) {
2125 unsigned int l = desc->elem_size - copied;
2126
2127 if (encode)
2128 memcpy(c, elem + copied, l);
2129 else {
2130 memcpy(elem + copied, c, l);
2131 err = desc->xcode(desc, elem);
2132 if (err)
2133 goto out;
2134 }
2135 todo -= l;
2136 c += l;
2137 }
2138 while (todo) {
2139 err = desc->xcode(desc, c);
2140 if (err)
2141 goto out;
2142 c += desc->elem_size;
2143 todo -= desc->elem_size;
2144 }
2145 }
2146 err = 0;
2147
2148 out:
2149 kfree(elem);
2150 if (ppages)
2151 kunmap(*ppages);
2152 return err;
2153 }
2154
2155 int xdr_decode_array2(const struct xdr_buf *buf, unsigned int base,
2156 struct xdr_array2_desc *desc)
2157 {
2158 if (base >= buf->len)
2159 return -EINVAL;
2160
2161 return xdr_xcode_array2(buf, base, desc, 0);
2162 }
2163 EXPORT_SYMBOL_GPL(xdr_decode_array2);
2164
2165 int xdr_encode_array2(const struct xdr_buf *buf, unsigned int base,
2166 struct xdr_array2_desc *desc)
2167 {
2168 if ((unsigned long) base + 4 + desc->array_len * desc->elem_size >
2169 buf->head->iov_len + buf->page_len + buf->tail->iov_len)
2170 return -EINVAL;
2171
2172 return xdr_xcode_array2(buf, base, desc, 1);
2173 }
2174 EXPORT_SYMBOL_GPL(xdr_encode_array2);
2175
2176 int xdr_process_buf(const struct xdr_buf *buf, unsigned int offset,
2177 unsigned int len,
2178 int (*actor)(struct scatterlist *, void *), void *data)
2179 {
2180 int i, ret = 0;
2181 unsigned int page_len, thislen, page_offset;
2182 struct scatterlist sg[1];
2183
2184 sg_init_table(sg, 1);
2185
2186 if (offset >= buf->head[0].iov_len) {
2187 offset -= buf->head[0].iov_len;
2188 } else {
2189 thislen = buf->head[0].iov_len - offset;
2190 if (thislen > len)
2191 thislen = len;
2192 sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
2193 ret = actor(sg, data);
2194 if (ret)
2195 goto out;
2196 offset = 0;
2197 len -= thislen;
2198 }
2199 if (len == 0)
2200 goto out;
2201
2202 if (offset >= buf->page_len) {
2203 offset -= buf->page_len;
2204 } else {
2205 page_len = buf->page_len - offset;
2206 if (page_len > len)
2207 page_len = len;
2208 len -= page_len;
2209 page_offset = (offset + buf->page_base) & (PAGE_SIZE - 1);
2210 i = (offset + buf->page_base) >> PAGE_SHIFT;
2211 thislen = PAGE_SIZE - page_offset;
2212 do {
2213 if (thislen > page_len)
2214 thislen = page_len;
2215 sg_set_page(sg, buf->pages[i], thislen, page_offset);
2216 ret = actor(sg, data);
2217 if (ret)
2218 goto out;
2219 page_len -= thislen;
2220 i++;
2221 page_offset = 0;
2222 thislen = PAGE_SIZE;
2223 } while (page_len != 0);
2224 offset = 0;
2225 }
2226 if (len == 0)
2227 goto out;
2228 if (offset < buf->tail[0].iov_len) {
2229 thislen = buf->tail[0].iov_len - offset;
2230 if (thislen > len)
2231 thislen = len;
2232 sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
2233 ret = actor(sg, data);
2234 len -= thislen;
2235 }
2236 if (len != 0)
2237 ret = -EINVAL;
2238 out:
2239 return ret;
2240 }
2241 EXPORT_SYMBOL_GPL(xdr_process_buf);
2242
2243 /**
2244 * xdr_stream_decode_opaque - Decode variable length opaque
2245 * @xdr: pointer to xdr_stream
2246 * @ptr: location to store opaque data
2247 * @size: size of storage buffer @ptr
2248 *
2249 * Return values:
2250 * On success, returns size of object stored in *@ptr
2251 * %-EBADMSG on XDR buffer overflow
2252 * %-EMSGSIZE on overflow of storage buffer @ptr
2253 */
2254 ssize_t xdr_stream_decode_opaque(struct xdr_stream *xdr, void *ptr, size_t size)
2255 {
2256 ssize_t ret;
2257 void *p;
2258
2259 ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
2260 if (ret <= 0)
2261 return ret;
2262 memcpy(ptr, p, ret);
2263 return ret;
2264 }
2265 EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque);
2266
2267 /**
2268 * xdr_stream_decode_opaque_dup - Decode and duplicate variable length opaque
2269 * @xdr: pointer to xdr_stream
2270 * @ptr: location to store pointer to opaque data
2271 * @maxlen: maximum acceptable object size
2272 * @gfp_flags: GFP mask to use
2273 *
2274 * Return values:
2275 * On success, returns size of object stored in *@ptr
2276 * %-EBADMSG on XDR buffer overflow
2277 * %-EMSGSIZE if the size of the object would exceed @maxlen
2278 * %-ENOMEM on memory allocation failure
2279 */
2280 ssize_t xdr_stream_decode_opaque_dup(struct xdr_stream *xdr, void **ptr,
2281 size_t maxlen, gfp_t gfp_flags)
2282 {
2283 ssize_t ret;
2284 void *p;
2285
2286 ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
2287 if (ret > 0) {
2288 *ptr = kmemdup(p, ret, gfp_flags);
2289 if (*ptr != NULL)
2290 return ret;
2291 ret = -ENOMEM;
2292 }
2293 *ptr = NULL;
2294 return ret;
2295 }
2296 EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque_dup);
2297
2298 /**
2299 * xdr_stream_decode_string - Decode variable length string
2300 * @xdr: pointer to xdr_stream
2301 * @str: location to store string
2302 * @size: size of storage buffer @str
2303 *
2304 * Return values:
2305 * On success, returns length of NUL-terminated string stored in *@str
2306 * %-EBADMSG on XDR buffer overflow
2307 * %-EMSGSIZE on overflow of storage buffer @str
2308 */
2309 ssize_t xdr_stream_decode_string(struct xdr_stream *xdr, char *str, size_t size)
2310 {
2311 ssize_t ret;
2312 void *p;
2313
2314 ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
2315 if (ret > 0) {
2316 memcpy(str, p, ret);
2317 str[ret] = '\0';
2318 return strlen(str);
2319 }
2320 *str = '\0';
2321 return ret;
2322 }
2323 EXPORT_SYMBOL_GPL(xdr_stream_decode_string);
2324
2325 /**
2326 * xdr_stream_decode_string_dup - Decode and duplicate variable length string
2327 * @xdr: pointer to xdr_stream
2328 * @str: location to store pointer to string
2329 * @maxlen: maximum acceptable string length
2330 * @gfp_flags: GFP mask to use
2331 *
2332 * Return values:
2333 * On success, returns length of NUL-terminated string stored in *@ptr
2334 * %-EBADMSG on XDR buffer overflow
2335 * %-EMSGSIZE if the size of the string would exceed @maxlen
2336 * %-ENOMEM on memory allocation failure
2337 */
2338 ssize_t xdr_stream_decode_string_dup(struct xdr_stream *xdr, char **str,
2339 size_t maxlen, gfp_t gfp_flags)
2340 {
2341 void *p;
2342 ssize_t ret;
2343
2344 ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
2345 if (ret > 0) {
2346 char *s = kmemdup_nul(p, ret, gfp_flags);
2347 if (s != NULL) {
2348 *str = s;
2349 return strlen(s);
2350 }
2351 ret = -ENOMEM;
2352 }
2353 *str = NULL;
2354 return ret;
2355 }
2356 EXPORT_SYMBOL_GPL(xdr_stream_decode_string_dup);
2357
2358 /**
2359 * xdr_stream_decode_opaque_auth - Decode struct opaque_auth (RFC5531 S8.2)
2360 * @xdr: pointer to xdr_stream
2361 * @flavor: location to store decoded flavor
2362 * @body: location to store decode body
2363 * @body_len: location to store length of decoded body
2364 *
2365 * Return values:
2366 * On success, returns the number of buffer bytes consumed
2367 * %-EBADMSG on XDR buffer overflow
2368 * %-EMSGSIZE if the decoded size of the body field exceeds 400 octets
2369 */
2370 ssize_t xdr_stream_decode_opaque_auth(struct xdr_stream *xdr, u32 *flavor,
2371 void **body, unsigned int *body_len)
2372 {
2373 ssize_t ret, len;
2374
2375 len = xdr_stream_decode_u32(xdr, flavor);
2376 if (unlikely(len < 0))
2377 return len;
2378 ret = xdr_stream_decode_opaque_inline(xdr, body, RPC_MAX_AUTH_SIZE);
2379 if (unlikely(ret < 0))
2380 return ret;
2381 *body_len = ret;
2382 return len + ret;
2383 }
2384 EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque_auth);
2385
2386 /**
2387 * xdr_stream_encode_opaque_auth - Encode struct opaque_auth (RFC5531 S8.2)
2388 * @xdr: pointer to xdr_stream
2389 * @flavor: verifier flavor to encode
2390 * @body: content of body to encode
2391 * @body_len: length of body to encode
2392 *
2393 * Return values:
2394 * On success, returns length in bytes of XDR buffer consumed
2395 * %-EBADMSG on XDR buffer overflow
2396 * %-EMSGSIZE if the size of @body exceeds 400 octets
2397 */
2398 ssize_t xdr_stream_encode_opaque_auth(struct xdr_stream *xdr, u32 flavor,
2399 void *body, unsigned int body_len)
2400 {
2401 ssize_t ret, len;
2402
2403 if (unlikely(body_len > RPC_MAX_AUTH_SIZE))
2404 return -EMSGSIZE;
2405 len = xdr_stream_encode_u32(xdr, flavor);
2406 if (unlikely(len < 0))
2407 return len;
2408 ret = xdr_stream_encode_opaque(xdr, body, body_len);
2409 if (unlikely(ret < 0))
2410 return ret;
2411 return len + ret;
2412 }
2413 EXPORT_SYMBOL_GPL(xdr_stream_encode_opaque_auth);
2414
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