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 /*
23 * XDR functions for basic NFS types
24 */
25 __be32 *
26 xdr_encode_netobj(__be32 *p, const struct xdr_netobj *obj)
27 {
28 unsigned int quadlen = XDR_QUADLEN(obj->len);
29
30 p[quadlen] = 0; /* zero trailing bytes */
31 *p++ = cpu_to_be32(obj->len);
32 memcpy(p, obj->data, obj->len);
33 return p + XDR_QUADLEN(obj->len);
34 }
35 EXPORT_SYMBOL_GPL(xdr_encode_netobj);
36
37 __be32 *
38 xdr_decode_netobj(__be32 *p, struct xdr_netobj *obj)
39 {
40 unsigned int len;
41
42 if ((len = be32_to_cpu(*p++)) > XDR_MAX_NETOBJ)
43 return NULL;
44 obj->len = len;
45 obj->data = (u8 *) p;
46 return p + XDR_QUADLEN(len);
47 }
48 EXPORT_SYMBOL_GPL(xdr_decode_netobj);
49
50 /**
51 * xdr_encode_opaque_fixed - Encode fixed length opaque data
52 * @p: pointer to current position in XDR buffer.
53 * @ptr: pointer to data to encode (or NULL)
54 * @nbytes: size of data.
55 *
56 * Copy the array of data of length nbytes at ptr to the XDR buffer
57 * at position p, then align to the next 32-bit boundary by padding
58 * with zero bytes (see RFC1832).
59 * Note: if ptr is NULL, only the padding is performed.
60 *
61 * Returns the updated current XDR buffer position
62 *
63 */
64 __be32 *xdr_encode_opaque_fixed(__be32 *p, const void *ptr, unsigned int nbytes)
65 {
66 if (likely(nbytes != 0)) {
67 unsigned int quadlen = XDR_QUADLEN(nbytes);
68 unsigned int padding = (quadlen << 2) - nbytes;
69
70 if (ptr != NULL)
71 memcpy(p, ptr, nbytes);
72 if (padding != 0)
73 memset((char *)p + nbytes, 0, padding);
74 p += quadlen;
75 }
76 return p;
77 }
78 EXPORT_SYMBOL_GPL(xdr_encode_opaque_fixed);
79
80 /**
81 * xdr_encode_opaque - Encode variable length opaque data
82 * @p: pointer to current position in XDR buffer.
83 * @ptr: pointer to data to encode (or NULL)
84 * @nbytes: size of data.
85 *
86 * Returns the updated current XDR buffer position
87 */
88 __be32 *xdr_encode_opaque(__be32 *p, const void *ptr, unsigned int nbytes)
89 {
90 *p++ = cpu_to_be32(nbytes);
91 return xdr_encode_opaque_fixed(p, ptr, nbytes);
92 }
93 EXPORT_SYMBOL_GPL(xdr_encode_opaque);
94
95 __be32 *
96 xdr_encode_string(__be32 *p, const char *string)
97 {
98 return xdr_encode_array(p, string, strlen(string));
99 }
100 EXPORT_SYMBOL_GPL(xdr_encode_string);
101
102 __be32 *
103 xdr_decode_string_inplace(__be32 *p, char **sp,
104 unsigned int *lenp, unsigned int maxlen)
105 {
106 u32 len;
107
108 len = be32_to_cpu(*p++);
109 if (len > maxlen)
110 return NULL;
111 *lenp = len;
112 *sp = (char *) p;
113 return p + XDR_QUADLEN(len);
114 }
115 EXPORT_SYMBOL_GPL(xdr_decode_string_inplace);
116
117 /**
118 * xdr_terminate_string - '\0'-terminate a string residing in an xdr_buf
119 * @buf: XDR buffer where string resides
120 * @len: length of string, in bytes
121 *
122 */
123 void
124 xdr_terminate_string(struct xdr_buf *buf, const u32 len)
125 {
126 char *kaddr;
127
128 kaddr = kmap_atomic(buf->pages[0]);
129 kaddr[buf->page_base + len] = '\0';
130 kunmap_atomic(kaddr);
131 }
132 EXPORT_SYMBOL_GPL(xdr_terminate_string);
133
134 size_t
135 xdr_buf_pagecount(struct xdr_buf *buf)
136 {
137 if (!buf->page_len)
138 return 0;
139 return (buf->page_base + buf->page_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
140 }
141
142 int
143 xdr_alloc_bvec(struct xdr_buf *buf, gfp_t gfp)
144 {
145 size_t i, n = xdr_buf_pagecount(buf);
146
147 if (n != 0 && buf->bvec == NULL) {
148 buf->bvec = kmalloc_array(n, sizeof(buf->bvec[0]), gfp);
149 if (!buf->bvec)
150 return -ENOMEM;
151 for (i = 0; i < n; i++) {
152 buf->bvec[i].bv_page = buf->pages[i];
153 buf->bvec[i].bv_len = PAGE_SIZE;
154 buf->bvec[i].bv_offset = 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_inline_pages - Prepare receive buffer for a large reply
169 * @xdr: xdr_buf into which reply will be placed
170 * @offset: expected offset where data payload will start, in bytes
171 * @pages: vector of struct page pointers
172 * @base: offset in first page where receive should start, in bytes
173 * @len: expected size of the upper layer data payload, in bytes
174 *
175 */
176 void
177 xdr_inline_pages(struct xdr_buf *xdr, unsigned int offset,
178 struct page **pages, unsigned int base, unsigned int len)
179 {
180 struct kvec *head = xdr->head;
181 struct kvec *tail = xdr->tail;
182 char *buf = (char *)head->iov_base;
183 unsigned int buflen = head->iov_len;
184
185 head->iov_len = offset;
186
187 xdr->pages = pages;
188 xdr->page_base = base;
189 xdr->page_len = len;
190
191 tail->iov_base = buf + offset;
192 tail->iov_len = buflen - offset;
193 if ((xdr->page_len & 3) == 0)
194 tail->iov_len -= sizeof(__be32);
195
196 xdr->buflen += len;
197 }
198 EXPORT_SYMBOL_GPL(xdr_inline_pages);
199
200 /*
201 * Helper routines for doing 'memmove' like operations on a struct xdr_buf
202 */
203
204 /**
205 * _shift_data_right_pages
206 * @pages: vector of pages containing both the source and dest memory area.
207 * @pgto_base: page vector address of destination
208 * @pgfrom_base: page vector address of source
209 * @len: number of bytes to copy
210 *
211 * Note: the addresses pgto_base and pgfrom_base are both calculated in
212 * the same way:
213 * if a memory area starts at byte 'base' in page 'pages[i]',
214 * then its address is given as (i << PAGE_SHIFT) + base
215 * Also note: pgfrom_base must be < pgto_base, but the memory areas
216 * they point to may overlap.
217 */
218 static void
219 _shift_data_right_pages(struct page **pages, size_t pgto_base,
220 size_t pgfrom_base, size_t len)
221 {
222 struct page **pgfrom, **pgto;
223 char *vfrom, *vto;
224 size_t copy;
225
226 BUG_ON(pgto_base <= pgfrom_base);
227
228 pgto_base += len;
229 pgfrom_base += len;
230
231 pgto = pages + (pgto_base >> PAGE_SHIFT);
232 pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);
233
234 pgto_base &= ~PAGE_MASK;
235 pgfrom_base &= ~PAGE_MASK;
236
237 do {
238 /* Are any pointers crossing a page boundary? */
239 if (pgto_base == 0) {
240 pgto_base = PAGE_SIZE;
241 pgto--;
242 }
243 if (pgfrom_base == 0) {
244 pgfrom_base = PAGE_SIZE;
245 pgfrom--;
246 }
247
248 copy = len;
249 if (copy > pgto_base)
250 copy = pgto_base;
251 if (copy > pgfrom_base)
252 copy = pgfrom_base;
253 pgto_base -= copy;
254 pgfrom_base -= copy;
255
256 vto = kmap_atomic(*pgto);
257 if (*pgto != *pgfrom) {
258 vfrom = kmap_atomic(*pgfrom);
259 memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);
260 kunmap_atomic(vfrom);
261 } else
262 memmove(vto + pgto_base, vto + pgfrom_base, copy);
263 flush_dcache_page(*pgto);
264 kunmap_atomic(vto);
265
266 } while ((len -= copy) != 0);
267 }
268
269 /**
270 * _copy_to_pages
271 * @pages: array of pages
272 * @pgbase: page vector address of destination
273 * @p: pointer to source data
274 * @len: length
275 *
276 * Copies data from an arbitrary memory location into an array of pages
277 * The copy is assumed to be non-overlapping.
278 */
279 static void
280 _copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len)
281 {
282 struct page **pgto;
283 char *vto;
284 size_t copy;
285
286 pgto = pages + (pgbase >> PAGE_SHIFT);
287 pgbase &= ~PAGE_MASK;
288
289 for (;;) {
290 copy = PAGE_SIZE - pgbase;
291 if (copy > len)
292 copy = len;
293
294 vto = kmap_atomic(*pgto);
295 memcpy(vto + pgbase, p, copy);
296 kunmap_atomic(vto);
297
298 len -= copy;
299 if (len == 0)
300 break;
301
302 pgbase += copy;
303 if (pgbase == PAGE_SIZE) {
304 flush_dcache_page(*pgto);
305 pgbase = 0;
306 pgto++;
307 }
308 p += copy;
309 }
310 flush_dcache_page(*pgto);
311 }
312
313 /**
314 * _copy_from_pages
315 * @p: pointer to destination
316 * @pages: array of pages
317 * @pgbase: offset of source data
318 * @len: length
319 *
320 * Copies data into an arbitrary memory location from an array of pages
321 * The copy is assumed to be non-overlapping.
322 */
323 void
324 _copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
325 {
326 struct page **pgfrom;
327 char *vfrom;
328 size_t copy;
329
330 pgfrom = pages + (pgbase >> PAGE_SHIFT);
331 pgbase &= ~PAGE_MASK;
332
333 do {
334 copy = PAGE_SIZE - pgbase;
335 if (copy > len)
336 copy = len;
337
338 vfrom = kmap_atomic(*pgfrom);
339 memcpy(p, vfrom + pgbase, copy);
340 kunmap_atomic(vfrom);
341
342 pgbase += copy;
343 if (pgbase == PAGE_SIZE) {
344 pgbase = 0;
345 pgfrom++;
346 }
347 p += copy;
348
349 } while ((len -= copy) != 0);
350 }
351 EXPORT_SYMBOL_GPL(_copy_from_pages);
352
353 /**
354 * xdr_shrink_bufhead
355 * @buf: xdr_buf
356 * @len: bytes to remove from buf->head[0]
357 *
358 * Shrinks XDR buffer's header kvec buf->head[0] by
359 * 'len' bytes. The extra data is not lost, but is instead
360 * moved into the inlined pages and/or the tail.
361 */
362 static unsigned int
363 xdr_shrink_bufhead(struct xdr_buf *buf, size_t len)
364 {
365 struct kvec *head, *tail;
366 size_t copy, offs;
367 unsigned int pglen = buf->page_len;
368 unsigned int result;
369
370 result = 0;
371 tail = buf->tail;
372 head = buf->head;
373
374 WARN_ON_ONCE(len > head->iov_len);
375 if (len > head->iov_len)
376 len = head->iov_len;
377
378 /* Shift the tail first */
379 if (tail->iov_len != 0) {
380 if (tail->iov_len > len) {
381 copy = tail->iov_len - len;
382 memmove((char *)tail->iov_base + len,
383 tail->iov_base, copy);
384 result += copy;
385 }
386 /* Copy from the inlined pages into the tail */
387 copy = len;
388 if (copy > pglen)
389 copy = pglen;
390 offs = len - copy;
391 if (offs >= tail->iov_len)
392 copy = 0;
393 else if (copy > tail->iov_len - offs)
394 copy = tail->iov_len - offs;
395 if (copy != 0) {
396 _copy_from_pages((char *)tail->iov_base + offs,
397 buf->pages,
398 buf->page_base + pglen + offs - len,
399 copy);
400 result += copy;
401 }
402 /* Do we also need to copy data from the head into the tail ? */
403 if (len > pglen) {
404 offs = copy = len - pglen;
405 if (copy > tail->iov_len)
406 copy = tail->iov_len;
407 memcpy(tail->iov_base,
408 (char *)head->iov_base +
409 head->iov_len - offs,
410 copy);
411 result += copy;
412 }
413 }
414 /* Now handle pages */
415 if (pglen != 0) {
416 if (pglen > len)
417 _shift_data_right_pages(buf->pages,
418 buf->page_base + len,
419 buf->page_base,
420 pglen - len);
421 copy = len;
422 if (len > pglen)
423 copy = pglen;
424 _copy_to_pages(buf->pages, buf->page_base,
425 (char *)head->iov_base + head->iov_len - len,
426 copy);
427 result += copy;
428 }
429 head->iov_len -= len;
430 buf->buflen -= len;
431 /* Have we truncated the message? */
432 if (buf->len > buf->buflen)
433 buf->len = buf->buflen;
434
435 return result;
436 }
437
438 /**
439 * xdr_shrink_pagelen
440 * @buf: xdr_buf
441 * @len: bytes to remove from buf->pages
442 *
443 * Shrinks XDR buffer's page array buf->pages by
444 * 'len' bytes. The extra data is not lost, but is instead
445 * moved into the tail.
446 */
447 static unsigned int
448 xdr_shrink_pagelen(struct xdr_buf *buf, size_t len)
449 {
450 struct kvec *tail;
451 size_t copy;
452 unsigned int pglen = buf->page_len;
453 unsigned int tailbuf_len;
454 unsigned int result;
455
456 result = 0;
457 tail = buf->tail;
458 BUG_ON (len > pglen);
459
460 tailbuf_len = buf->buflen - buf->head->iov_len - buf->page_len;
461
462 /* Shift the tail first */
463 if (tailbuf_len != 0) {
464 unsigned int free_space = tailbuf_len - tail->iov_len;
465
466 if (len < free_space)
467 free_space = len;
468 tail->iov_len += free_space;
469
470 copy = len;
471 if (tail->iov_len > len) {
472 char *p = (char *)tail->iov_base + len;
473 memmove(p, tail->iov_base, tail->iov_len - len);
474 result += tail->iov_len - len;
475 } else
476 copy = tail->iov_len;
477 /* Copy from the inlined pages into the tail */
478 _copy_from_pages((char *)tail->iov_base,
479 buf->pages, buf->page_base + pglen - len,
480 copy);
481 result += copy;
482 }
483 buf->page_len -= len;
484 buf->buflen -= len;
485 /* Have we truncated the message? */
486 if (buf->len > buf->buflen)
487 buf->len = buf->buflen;
488
489 return result;
490 }
491
492 void
493 xdr_shift_buf(struct xdr_buf *buf, size_t len)
494 {
495 xdr_shrink_bufhead(buf, len);
496 }
497 EXPORT_SYMBOL_GPL(xdr_shift_buf);
498
499 /**
500 * xdr_stream_pos - Return the current offset from the start of the xdr_stream
501 * @xdr: pointer to struct xdr_stream
502 */
503 unsigned int xdr_stream_pos(const struct xdr_stream *xdr)
504 {
505 return (unsigned int)(XDR_QUADLEN(xdr->buf->len) - xdr->nwords) << 2;
506 }
507 EXPORT_SYMBOL_GPL(xdr_stream_pos);
508
509 /**
510 * xdr_init_encode - Initialize a struct xdr_stream for sending data.
511 * @xdr: pointer to xdr_stream struct
512 * @buf: pointer to XDR buffer in which to encode data
513 * @p: current pointer inside XDR buffer
514 * @rqst: pointer to controlling rpc_rqst, for debugging
515 *
516 * Note: at the moment the RPC client only passes the length of our
517 * scratch buffer in the xdr_buf's header kvec. Previously this
518 * meant we needed to call xdr_adjust_iovec() after encoding the
519 * data. With the new scheme, the xdr_stream manages the details
520 * of the buffer length, and takes care of adjusting the kvec
521 * length for us.
522 */
523 void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
524 struct rpc_rqst *rqst)
525 {
526 struct kvec *iov = buf->head;
527 int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len;
528
529 xdr_set_scratch_buffer(xdr, NULL, 0);
530 BUG_ON(scratch_len < 0);
531 xdr->buf = buf;
532 xdr->iov = iov;
533 xdr->p = (__be32 *)((char *)iov->iov_base + iov->iov_len);
534 xdr->end = (__be32 *)((char *)iov->iov_base + scratch_len);
535 BUG_ON(iov->iov_len > scratch_len);
536
537 if (p != xdr->p && p != NULL) {
538 size_t len;
539
540 BUG_ON(p < xdr->p || p > xdr->end);
541 len = (char *)p - (char *)xdr->p;
542 xdr->p = p;
543 buf->len += len;
544 iov->iov_len += len;
545 }
546 xdr->rqst = rqst;
547 }
548 EXPORT_SYMBOL_GPL(xdr_init_encode);
549
550 /**
551 * xdr_commit_encode - Ensure all data is written to buffer
552 * @xdr: pointer to xdr_stream
553 *
554 * We handle encoding across page boundaries by giving the caller a
555 * temporary location to write to, then later copying the data into
556 * place; xdr_commit_encode does that copying.
557 *
558 * Normally the caller doesn't need to call this directly, as the
559 * following xdr_reserve_space will do it. But an explicit call may be
560 * required at the end of encoding, or any other time when the xdr_buf
561 * data might be read.
562 */
563 void xdr_commit_encode(struct xdr_stream *xdr)
564 {
565 int shift = xdr->scratch.iov_len;
566 void *page;
567
568 if (shift == 0)
569 return;
570 page = page_address(*xdr->page_ptr);
571 memcpy(xdr->scratch.iov_base, page, shift);
572 memmove(page, page + shift, (void *)xdr->p - page);
573 xdr->scratch.iov_len = 0;
574 }
575 EXPORT_SYMBOL_GPL(xdr_commit_encode);
576
577 static __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr,
578 size_t nbytes)
579 {
580 __be32 *p;
581 int space_left;
582 int frag1bytes, frag2bytes;
583
584 if (nbytes > PAGE_SIZE)
585 goto out_overflow; /* Bigger buffers require special handling */
586 if (xdr->buf->len + nbytes > xdr->buf->buflen)
587 goto out_overflow; /* Sorry, we're totally out of space */
588 frag1bytes = (xdr->end - xdr->p) << 2;
589 frag2bytes = nbytes - frag1bytes;
590 if (xdr->iov)
591 xdr->iov->iov_len += frag1bytes;
592 else
593 xdr->buf->page_len += frag1bytes;
594 xdr->page_ptr++;
595 xdr->iov = NULL;
596 /*
597 * If the last encode didn't end exactly on a page boundary, the
598 * next one will straddle boundaries. Encode into the next
599 * page, then copy it back later in xdr_commit_encode. We use
600 * the "scratch" iov to track any temporarily unused fragment of
601 * space at the end of the previous buffer:
602 */
603 xdr->scratch.iov_base = xdr->p;
604 xdr->scratch.iov_len = frag1bytes;
605 p = page_address(*xdr->page_ptr);
606 /*
607 * Note this is where the next encode will start after we've
608 * shifted this one back:
609 */
610 xdr->p = (void *)p + frag2bytes;
611 space_left = xdr->buf->buflen - xdr->buf->len;
612 xdr->end = (void *)p + min_t(int, space_left, PAGE_SIZE);
613 xdr->buf->page_len += frag2bytes;
614 xdr->buf->len += nbytes;
615 return p;
616 out_overflow:
617 trace_rpc_xdr_overflow(xdr, nbytes);
618 return NULL;
619 }
620
621 /**
622 * xdr_reserve_space - Reserve buffer space for sending
623 * @xdr: pointer to xdr_stream
624 * @nbytes: number of bytes to reserve
625 *
626 * Checks that we have enough buffer space to encode 'nbytes' more
627 * bytes of data. If so, update the total xdr_buf length, and
628 * adjust the length of the current kvec.
629 */
630 __be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
631 {
632 __be32 *p = xdr->p;
633 __be32 *q;
634
635 xdr_commit_encode(xdr);
636 /* align nbytes on the next 32-bit boundary */
637 nbytes += 3;
638 nbytes &= ~3;
639 q = p + (nbytes >> 2);
640 if (unlikely(q > xdr->end || q < p))
641 return xdr_get_next_encode_buffer(xdr, nbytes);
642 xdr->p = q;
643 if (xdr->iov)
644 xdr->iov->iov_len += nbytes;
645 else
646 xdr->buf->page_len += nbytes;
647 xdr->buf->len += nbytes;
648 return p;
649 }
650 EXPORT_SYMBOL_GPL(xdr_reserve_space);
651
652 /**
653 * xdr_truncate_encode - truncate an encode buffer
654 * @xdr: pointer to xdr_stream
655 * @len: new length of buffer
656 *
657 * Truncates the xdr stream, so that xdr->buf->len == len,
658 * and xdr->p points at offset len from the start of the buffer, and
659 * head, tail, and page lengths are adjusted to correspond.
660 *
661 * If this means moving xdr->p to a different buffer, we assume that
662 * that the end pointer should be set to the end of the current page,
663 * except in the case of the head buffer when we assume the head
664 * buffer's current length represents the end of the available buffer.
665 *
666 * This is *not* safe to use on a buffer that already has inlined page
667 * cache pages (as in a zero-copy server read reply), except for the
668 * simple case of truncating from one position in the tail to another.
669 *
670 */
671 void xdr_truncate_encode(struct xdr_stream *xdr, size_t len)
672 {
673 struct xdr_buf *buf = xdr->buf;
674 struct kvec *head = buf->head;
675 struct kvec *tail = buf->tail;
676 int fraglen;
677 int new;
678
679 if (len > buf->len) {
680 WARN_ON_ONCE(1);
681 return;
682 }
683 xdr_commit_encode(xdr);
684
685 fraglen = min_t(int, buf->len - len, tail->iov_len);
686 tail->iov_len -= fraglen;
687 buf->len -= fraglen;
688 if (tail->iov_len) {
689 xdr->p = tail->iov_base + tail->iov_len;
690 WARN_ON_ONCE(!xdr->end);
691 WARN_ON_ONCE(!xdr->iov);
692 return;
693 }
694 WARN_ON_ONCE(fraglen);
695 fraglen = min_t(int, buf->len - len, buf->page_len);
696 buf->page_len -= fraglen;
697 buf->len -= fraglen;
698
699 new = buf->page_base + buf->page_len;
700
701 xdr->page_ptr = buf->pages + (new >> PAGE_SHIFT);
702
703 if (buf->page_len) {
704 xdr->p = page_address(*xdr->page_ptr);
705 xdr->end = (void *)xdr->p + PAGE_SIZE;
706 xdr->p = (void *)xdr->p + (new % PAGE_SIZE);
707 WARN_ON_ONCE(xdr->iov);
708 return;
709 }
710 if (fraglen)
711 xdr->end = head->iov_base + head->iov_len;
712 /* (otherwise assume xdr->end is already set) */
713 xdr->page_ptr--;
714 head->iov_len = len;
715 buf->len = len;
716 xdr->p = head->iov_base + head->iov_len;
717 xdr->iov = buf->head;
718 }
719 EXPORT_SYMBOL(xdr_truncate_encode);
720
721 /**
722 * xdr_restrict_buflen - decrease available buffer space
723 * @xdr: pointer to xdr_stream
724 * @newbuflen: new maximum number of bytes available
725 *
726 * Adjust our idea of how much space is available in the buffer.
727 * If we've already used too much space in the buffer, returns -1.
728 * If the available space is already smaller than newbuflen, returns 0
729 * and does nothing. Otherwise, adjusts xdr->buf->buflen to newbuflen
730 * and ensures xdr->end is set at most offset newbuflen from the start
731 * of the buffer.
732 */
733 int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen)
734 {
735 struct xdr_buf *buf = xdr->buf;
736 int left_in_this_buf = (void *)xdr->end - (void *)xdr->p;
737 int end_offset = buf->len + left_in_this_buf;
738
739 if (newbuflen < 0 || newbuflen < buf->len)
740 return -1;
741 if (newbuflen > buf->buflen)
742 return 0;
743 if (newbuflen < end_offset)
744 xdr->end = (void *)xdr->end + newbuflen - end_offset;
745 buf->buflen = newbuflen;
746 return 0;
747 }
748 EXPORT_SYMBOL(xdr_restrict_buflen);
749
750 /**
751 * xdr_write_pages - Insert a list of pages into an XDR buffer for sending
752 * @xdr: pointer to xdr_stream
753 * @pages: list of pages
754 * @base: offset of first byte
755 * @len: length of data in bytes
756 *
757 */
758 void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base,
759 unsigned int len)
760 {
761 struct xdr_buf *buf = xdr->buf;
762 struct kvec *iov = buf->tail;
763 buf->pages = pages;
764 buf->page_base = base;
765 buf->page_len = len;
766
767 iov->iov_base = (char *)xdr->p;
768 iov->iov_len = 0;
769 xdr->iov = iov;
770
771 if (len & 3) {
772 unsigned int pad = 4 - (len & 3);
773
774 BUG_ON(xdr->p >= xdr->end);
775 iov->iov_base = (char *)xdr->p + (len & 3);
776 iov->iov_len += pad;
777 len += pad;
778 *xdr->p++ = 0;
779 }
780 buf->buflen += len;
781 buf->len += len;
782 }
783 EXPORT_SYMBOL_GPL(xdr_write_pages);
784
785 static void xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
786 unsigned int len)
787 {
788 if (len > iov->iov_len)
789 len = iov->iov_len;
790 xdr->p = (__be32*)iov->iov_base;
791 xdr->end = (__be32*)(iov->iov_base + len);
792 xdr->iov = iov;
793 xdr->page_ptr = NULL;
794 }
795
796 static int xdr_set_page_base(struct xdr_stream *xdr,
797 unsigned int base, unsigned int len)
798 {
799 unsigned int pgnr;
800 unsigned int maxlen;
801 unsigned int pgoff;
802 unsigned int pgend;
803 void *kaddr;
804
805 maxlen = xdr->buf->page_len;
806 if (base >= maxlen)
807 return -EINVAL;
808 maxlen -= base;
809 if (len > maxlen)
810 len = maxlen;
811
812 base += xdr->buf->page_base;
813
814 pgnr = base >> PAGE_SHIFT;
815 xdr->page_ptr = &xdr->buf->pages[pgnr];
816 kaddr = page_address(*xdr->page_ptr);
817
818 pgoff = base & ~PAGE_MASK;
819 xdr->p = (__be32*)(kaddr + pgoff);
820
821 pgend = pgoff + len;
822 if (pgend > PAGE_SIZE)
823 pgend = PAGE_SIZE;
824 xdr->end = (__be32*)(kaddr + pgend);
825 xdr->iov = NULL;
826 return 0;
827 }
828
829 static void xdr_set_next_page(struct xdr_stream *xdr)
830 {
831 unsigned int newbase;
832
833 newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT;
834 newbase -= xdr->buf->page_base;
835
836 if (xdr_set_page_base(xdr, newbase, PAGE_SIZE) < 0)
837 xdr_set_iov(xdr, xdr->buf->tail, xdr->nwords << 2);
838 }
839
840 static bool xdr_set_next_buffer(struct xdr_stream *xdr)
841 {
842 if (xdr->page_ptr != NULL)
843 xdr_set_next_page(xdr);
844 else if (xdr->iov == xdr->buf->head) {
845 if (xdr_set_page_base(xdr, 0, PAGE_SIZE) < 0)
846 xdr_set_iov(xdr, xdr->buf->tail, xdr->nwords << 2);
847 }
848 return xdr->p != xdr->end;
849 }
850
851 /**
852 * xdr_init_decode - Initialize an xdr_stream for decoding data.
853 * @xdr: pointer to xdr_stream struct
854 * @buf: pointer to XDR buffer from which to decode data
855 * @p: current pointer inside XDR buffer
856 * @rqst: pointer to controlling rpc_rqst, for debugging
857 */
858 void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
859 struct rpc_rqst *rqst)
860 {
861 xdr->buf = buf;
862 xdr->scratch.iov_base = NULL;
863 xdr->scratch.iov_len = 0;
864 xdr->nwords = XDR_QUADLEN(buf->len);
865 if (buf->head[0].iov_len != 0)
866 xdr_set_iov(xdr, buf->head, buf->len);
867 else if (buf->page_len != 0)
868 xdr_set_page_base(xdr, 0, buf->len);
869 else
870 xdr_set_iov(xdr, buf->head, buf->len);
871 if (p != NULL && p > xdr->p && xdr->end >= p) {
872 xdr->nwords -= p - xdr->p;
873 xdr->p = p;
874 }
875 xdr->rqst = rqst;
876 }
877 EXPORT_SYMBOL_GPL(xdr_init_decode);
878
879 /**
880 * xdr_init_decode_pages - Initialize an xdr_stream for decoding into pages
881 * @xdr: pointer to xdr_stream struct
882 * @buf: pointer to XDR buffer from which to decode data
883 * @pages: list of pages to decode into
884 * @len: length in bytes of buffer in pages
885 */
886 void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
887 struct page **pages, unsigned int len)
888 {
889 memset(buf, 0, sizeof(*buf));
890 buf->pages = pages;
891 buf->page_len = len;
892 buf->buflen = len;
893 buf->len = len;
894 xdr_init_decode(xdr, buf, NULL, NULL);
895 }
896 EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
897
898 static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
899 {
900 unsigned int nwords = XDR_QUADLEN(nbytes);
901 __be32 *p = xdr->p;
902 __be32 *q = p + nwords;
903
904 if (unlikely(nwords > xdr->nwords || q > xdr->end || q < p))
905 return NULL;
906 xdr->p = q;
907 xdr->nwords -= nwords;
908 return p;
909 }
910
911 /**
912 * xdr_set_scratch_buffer - Attach a scratch buffer for decoding data.
913 * @xdr: pointer to xdr_stream struct
914 * @buf: pointer to an empty buffer
915 * @buflen: size of 'buf'
916 *
917 * The scratch buffer is used when decoding from an array of pages.
918 * If an xdr_inline_decode() call spans across page boundaries, then
919 * we copy the data into the scratch buffer in order to allow linear
920 * access.
921 */
922 void xdr_set_scratch_buffer(struct xdr_stream *xdr, void *buf, size_t buflen)
923 {
924 xdr->scratch.iov_base = buf;
925 xdr->scratch.iov_len = buflen;
926 }
927 EXPORT_SYMBOL_GPL(xdr_set_scratch_buffer);
928
929 static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes)
930 {
931 __be32 *p;
932 char *cpdest = xdr->scratch.iov_base;
933 size_t cplen = (char *)xdr->end - (char *)xdr->p;
934
935 if (nbytes > xdr->scratch.iov_len)
936 goto out_overflow;
937 p = __xdr_inline_decode(xdr, cplen);
938 if (p == NULL)
939 return NULL;
940 memcpy(cpdest, p, cplen);
941 if (!xdr_set_next_buffer(xdr))
942 goto out_overflow;
943 cpdest += cplen;
944 nbytes -= cplen;
945 p = __xdr_inline_decode(xdr, nbytes);
946 if (p == NULL)
947 return NULL;
948 memcpy(cpdest, p, nbytes);
949 return xdr->scratch.iov_base;
950 out_overflow:
951 trace_rpc_xdr_overflow(xdr, nbytes);
952 return NULL;
953 }
954
955 /**
956 * xdr_inline_decode - Retrieve XDR data to decode
957 * @xdr: pointer to xdr_stream struct
958 * @nbytes: number of bytes of data to decode
959 *
960 * Check if the input buffer is long enough to enable us to decode
961 * 'nbytes' more bytes of data starting at the current position.
962 * If so return the current pointer, then update the current
963 * pointer position.
964 */
965 __be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
966 {
967 __be32 *p;
968
969 if (unlikely(nbytes == 0))
970 return xdr->p;
971 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
972 goto out_overflow;
973 p = __xdr_inline_decode(xdr, nbytes);
974 if (p != NULL)
975 return p;
976 return xdr_copy_to_scratch(xdr, nbytes);
977 out_overflow:
978 trace_rpc_xdr_overflow(xdr, nbytes);
979 return NULL;
980 }
981 EXPORT_SYMBOL_GPL(xdr_inline_decode);
982
983 static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len)
984 {
985 struct xdr_buf *buf = xdr->buf;
986 struct kvec *iov;
987 unsigned int nwords = XDR_QUADLEN(len);
988 unsigned int cur = xdr_stream_pos(xdr);
989 unsigned int copied, offset;
990
991 if (xdr->nwords == 0)
992 return 0;
993
994 /* Realign pages to current pointer position */
995 iov = buf->head;
996 if (iov->iov_len > cur) {
997 offset = iov->iov_len - cur;
998 copied = xdr_shrink_bufhead(buf, offset);
999 trace_rpc_xdr_alignment(xdr, offset, copied);
1000 xdr->nwords = XDR_QUADLEN(buf->len - cur);
1001 }
1002
1003 if (nwords > xdr->nwords) {
1004 nwords = xdr->nwords;
1005 len = nwords << 2;
1006 }
1007 if (buf->page_len <= len)
1008 len = buf->page_len;
1009 else if (nwords < xdr->nwords) {
1010 /* Truncate page data and move it into the tail */
1011 offset = buf->page_len - len;
1012 copied = xdr_shrink_pagelen(buf, offset);
1013 trace_rpc_xdr_alignment(xdr, offset, copied);
1014 xdr->nwords = XDR_QUADLEN(buf->len - cur);
1015 }
1016 return len;
1017 }
1018
1019 /**
1020 * xdr_read_pages - Ensure page-based XDR data to decode is aligned at current pointer position
1021 * @xdr: pointer to xdr_stream struct
1022 * @len: number of bytes of page data
1023 *
1024 * Moves data beyond the current pointer position from the XDR head[] buffer
1025 * into the page list. Any data that lies beyond current position + "len"
1026 * bytes is moved into the XDR tail[].
1027 *
1028 * Returns the number of XDR encoded bytes now contained in the pages
1029 */
1030 unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
1031 {
1032 struct xdr_buf *buf = xdr->buf;
1033 struct kvec *iov;
1034 unsigned int nwords;
1035 unsigned int end;
1036 unsigned int padding;
1037
1038 len = xdr_align_pages(xdr, len);
1039 if (len == 0)
1040 return 0;
1041 nwords = XDR_QUADLEN(len);
1042 padding = (nwords << 2) - len;
1043 xdr->iov = iov = buf->tail;
1044 /* Compute remaining message length. */
1045 end = ((xdr->nwords - nwords) << 2) + padding;
1046 if (end > iov->iov_len)
1047 end = iov->iov_len;
1048
1049 /*
1050 * Position current pointer at beginning of tail, and
1051 * set remaining message length.
1052 */
1053 xdr->p = (__be32 *)((char *)iov->iov_base + padding);
1054 xdr->end = (__be32 *)((char *)iov->iov_base + end);
1055 xdr->page_ptr = NULL;
1056 xdr->nwords = XDR_QUADLEN(end - padding);
1057 return len;
1058 }
1059 EXPORT_SYMBOL_GPL(xdr_read_pages);
1060
1061 /**
1062 * xdr_enter_page - decode data from the XDR page
1063 * @xdr: pointer to xdr_stream struct
1064 * @len: number of bytes of page data
1065 *
1066 * Moves data beyond the current pointer position from the XDR head[] buffer
1067 * into the page list. Any data that lies beyond current position + "len"
1068 * bytes is moved into the XDR tail[]. The current pointer is then
1069 * repositioned at the beginning of the first XDR page.
1070 */
1071 void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
1072 {
1073 len = xdr_align_pages(xdr, len);
1074 /*
1075 * Position current pointer at beginning of tail, and
1076 * set remaining message length.
1077 */
1078 if (len != 0)
1079 xdr_set_page_base(xdr, 0, len);
1080 }
1081 EXPORT_SYMBOL_GPL(xdr_enter_page);
1082
1083 static struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0};
1084
1085 void
1086 xdr_buf_from_iov(struct kvec *iov, struct xdr_buf *buf)
1087 {
1088 buf->head[0] = *iov;
1089 buf->tail[0] = empty_iov;
1090 buf->page_len = 0;
1091 buf->buflen = buf->len = iov->iov_len;
1092 }
1093 EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
1094
1095 /**
1096 * xdr_buf_subsegment - set subbuf to a portion of buf
1097 * @buf: an xdr buffer
1098 * @subbuf: the result buffer
1099 * @base: beginning of range in bytes
1100 * @len: length of range in bytes
1101 *
1102 * sets @subbuf to an xdr buffer representing the portion of @buf of
1103 * length @len starting at offset @base.
1104 *
1105 * @buf and @subbuf may be pointers to the same struct xdr_buf.
1106 *
1107 * Returns -1 if base of length are out of bounds.
1108 */
1109 int
1110 xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
1111 unsigned int base, unsigned int len)
1112 {
1113 subbuf->buflen = subbuf->len = len;
1114 if (base < buf->head[0].iov_len) {
1115 subbuf->head[0].iov_base = buf->head[0].iov_base + base;
1116 subbuf->head[0].iov_len = min_t(unsigned int, len,
1117 buf->head[0].iov_len - base);
1118 len -= subbuf->head[0].iov_len;
1119 base = 0;
1120 } else {
1121 base -= buf->head[0].iov_len;
1122 subbuf->head[0].iov_len = 0;
1123 }
1124
1125 if (base < buf->page_len) {
1126 subbuf->page_len = min(buf->page_len - base, len);
1127 base += buf->page_base;
1128 subbuf->page_base = base & ~PAGE_MASK;
1129 subbuf->pages = &buf->pages[base >> PAGE_SHIFT];
1130 len -= subbuf->page_len;
1131 base = 0;
1132 } else {
1133 base -= buf->page_len;
1134 subbuf->page_len = 0;
1135 }
1136
1137 if (base < buf->tail[0].iov_len) {
1138 subbuf->tail[0].iov_base = buf->tail[0].iov_base + base;
1139 subbuf->tail[0].iov_len = min_t(unsigned int, len,
1140 buf->tail[0].iov_len - base);
1141 len -= subbuf->tail[0].iov_len;
1142 base = 0;
1143 } else {
1144 base -= buf->tail[0].iov_len;
1145 subbuf->tail[0].iov_len = 0;
1146 }
1147
1148 if (base || len)
1149 return -1;
1150 return 0;
1151 }
1152 EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
1153
1154 static void __read_bytes_from_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
1155 {
1156 unsigned int this_len;
1157
1158 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1159 memcpy(obj, subbuf->head[0].iov_base, this_len);
1160 len -= this_len;
1161 obj += this_len;
1162 this_len = min_t(unsigned int, len, subbuf->page_len);
1163 if (this_len)
1164 _copy_from_pages(obj, subbuf->pages, subbuf->page_base, this_len);
1165 len -= this_len;
1166 obj += this_len;
1167 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1168 memcpy(obj, subbuf->tail[0].iov_base, this_len);
1169 }
1170
1171 /* obj is assumed to point to allocated memory of size at least len: */
1172 int read_bytes_from_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
1173 {
1174 struct xdr_buf subbuf;
1175 int status;
1176
1177 status = xdr_buf_subsegment(buf, &subbuf, base, len);
1178 if (status != 0)
1179 return status;
1180 __read_bytes_from_xdr_buf(&subbuf, obj, len);
1181 return 0;
1182 }
1183 EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf);
1184
1185 static void __write_bytes_to_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
1186 {
1187 unsigned int this_len;
1188
1189 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1190 memcpy(subbuf->head[0].iov_base, obj, this_len);
1191 len -= this_len;
1192 obj += this_len;
1193 this_len = min_t(unsigned int, len, subbuf->page_len);
1194 if (this_len)
1195 _copy_to_pages(subbuf->pages, subbuf->page_base, obj, this_len);
1196 len -= this_len;
1197 obj += this_len;
1198 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1199 memcpy(subbuf->tail[0].iov_base, obj, this_len);
1200 }
1201
1202 /* obj is assumed to point to allocated memory of size at least len: */
1203 int write_bytes_to_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
1204 {
1205 struct xdr_buf subbuf;
1206 int status;
1207
1208 status = xdr_buf_subsegment(buf, &subbuf, base, len);
1209 if (status != 0)
1210 return status;
1211 __write_bytes_to_xdr_buf(&subbuf, obj, len);
1212 return 0;
1213 }
1214 EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf);
1215
1216 int
1217 xdr_decode_word(struct xdr_buf *buf, unsigned int base, u32 *obj)
1218 {
1219 __be32 raw;
1220 int status;
1221
1222 status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
1223 if (status)
1224 return status;
1225 *obj = be32_to_cpu(raw);
1226 return 0;
1227 }
1228 EXPORT_SYMBOL_GPL(xdr_decode_word);
1229
1230 int
1231 xdr_encode_word(struct xdr_buf *buf, unsigned int base, u32 obj)
1232 {
1233 __be32 raw = cpu_to_be32(obj);
1234
1235 return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj));
1236 }
1237 EXPORT_SYMBOL_GPL(xdr_encode_word);
1238
1239 /* If the netobj starting offset bytes from the start of xdr_buf is contained
1240 * entirely in the head, pages, or tail, set object to point to it; otherwise
1241 * shift the buffer until it is contained entirely within the pages or tail.
1242 */
1243 int xdr_buf_read_netobj(struct xdr_buf *buf, struct xdr_netobj *obj, unsigned int offset)
1244 {
1245 struct xdr_buf subbuf;
1246 unsigned int boundary;
1247
1248 if (xdr_decode_word(buf, offset, &obj->len))
1249 return -EFAULT;
1250 offset += 4;
1251
1252 /* Is the obj partially in the head? */
1253 boundary = buf->head[0].iov_len;
1254 if (offset < boundary && (offset + obj->len) > boundary)
1255 xdr_shift_buf(buf, boundary - offset);
1256
1257 /* Is the obj partially in the pages? */
1258 boundary += buf->page_len;
1259 if (offset < boundary && (offset + obj->len) > boundary)
1260 xdr_shrink_pagelen(buf, boundary - offset);
1261
1262 if (xdr_buf_subsegment(buf, &subbuf, offset, obj->len))
1263 return -EFAULT;
1264
1265 /* Is the obj contained entirely in the head? */
1266 obj->data = subbuf.head[0].iov_base;
1267 if (subbuf.head[0].iov_len == obj->len)
1268 return 0;
1269 /* ..or is the obj contained entirely in the tail? */
1270 obj->data = subbuf.tail[0].iov_base;
1271 if (subbuf.tail[0].iov_len == obj->len)
1272 return 0;
1273
1274 /* Find a contiguous area in @buf to hold all of @obj */
1275 if (obj->len > buf->buflen - buf->len)
1276 return -ENOMEM;
1277 if (buf->tail[0].iov_len != 0)
1278 obj->data = buf->tail[0].iov_base + buf->tail[0].iov_len;
1279 else
1280 obj->data = buf->head[0].iov_base + buf->head[0].iov_len;
1281 __read_bytes_from_xdr_buf(&subbuf, obj->data, obj->len);
1282 return 0;
1283 }
1284 EXPORT_SYMBOL_GPL(xdr_buf_read_netobj);
1285
1286 /* Returns 0 on success, or else a negative error code. */
1287 static int
1288 xdr_xcode_array2(struct xdr_buf *buf, unsigned int base,
1289 struct xdr_array2_desc *desc, int encode)
1290 {
1291 char *elem = NULL, *c;
1292 unsigned int copied = 0, todo, avail_here;
1293 struct page **ppages = NULL;
1294 int err;
1295
1296 if (encode) {
1297 if (xdr_encode_word(buf, base, desc->array_len) != 0)
1298 return -EINVAL;
1299 } else {
1300 if (xdr_decode_word(buf, base, &desc->array_len) != 0 ||
1301 desc->array_len > desc->array_maxlen ||
1302 (unsigned long) base + 4 + desc->array_len *
1303 desc->elem_size > buf->len)
1304 return -EINVAL;
1305 }
1306 base += 4;
1307
1308 if (!desc->xcode)
1309 return 0;
1310
1311 todo = desc->array_len * desc->elem_size;
1312
1313 /* process head */
1314 if (todo && base < buf->head->iov_len) {
1315 c = buf->head->iov_base + base;
1316 avail_here = min_t(unsigned int, todo,
1317 buf->head->iov_len - base);
1318 todo -= avail_here;
1319
1320 while (avail_here >= desc->elem_size) {
1321 err = desc->xcode(desc, c);
1322 if (err)
1323 goto out;
1324 c += desc->elem_size;
1325 avail_here -= desc->elem_size;
1326 }
1327 if (avail_here) {
1328 if (!elem) {
1329 elem = kmalloc(desc->elem_size, GFP_KERNEL);
1330 err = -ENOMEM;
1331 if (!elem)
1332 goto out;
1333 }
1334 if (encode) {
1335 err = desc->xcode(desc, elem);
1336 if (err)
1337 goto out;
1338 memcpy(c, elem, avail_here);
1339 } else
1340 memcpy(elem, c, avail_here);
1341 copied = avail_here;
1342 }
1343 base = buf->head->iov_len; /* align to start of pages */
1344 }
1345
1346 /* process pages array */
1347 base -= buf->head->iov_len;
1348 if (todo && base < buf->page_len) {
1349 unsigned int avail_page;
1350
1351 avail_here = min(todo, buf->page_len - base);
1352 todo -= avail_here;
1353
1354 base += buf->page_base;
1355 ppages = buf->pages + (base >> PAGE_SHIFT);
1356 base &= ~PAGE_MASK;
1357 avail_page = min_t(unsigned int, PAGE_SIZE - base,
1358 avail_here);
1359 c = kmap(*ppages) + base;
1360
1361 while (avail_here) {
1362 avail_here -= avail_page;
1363 if (copied || avail_page < desc->elem_size) {
1364 unsigned int l = min(avail_page,
1365 desc->elem_size - copied);
1366 if (!elem) {
1367 elem = kmalloc(desc->elem_size,
1368 GFP_KERNEL);
1369 err = -ENOMEM;
1370 if (!elem)
1371 goto out;
1372 }
1373 if (encode) {
1374 if (!copied) {
1375 err = desc->xcode(desc, elem);
1376 if (err)
1377 goto out;
1378 }
1379 memcpy(c, elem + copied, l);
1380 copied += l;
1381 if (copied == desc->elem_size)
1382 copied = 0;
1383 } else {
1384 memcpy(elem + copied, c, l);
1385 copied += l;
1386 if (copied == desc->elem_size) {
1387 err = desc->xcode(desc, elem);
1388 if (err)
1389 goto out;
1390 copied = 0;
1391 }
1392 }
1393 avail_page -= l;
1394 c += l;
1395 }
1396 while (avail_page >= desc->elem_size) {
1397 err = desc->xcode(desc, c);
1398 if (err)
1399 goto out;
1400 c += desc->elem_size;
1401 avail_page -= desc->elem_size;
1402 }
1403 if (avail_page) {
1404 unsigned int l = min(avail_page,
1405 desc->elem_size - copied);
1406 if (!elem) {
1407 elem = kmalloc(desc->elem_size,
1408 GFP_KERNEL);
1409 err = -ENOMEM;
1410 if (!elem)
1411 goto out;
1412 }
1413 if (encode) {
1414 if (!copied) {
1415 err = desc->xcode(desc, elem);
1416 if (err)
1417 goto out;
1418 }
1419 memcpy(c, elem + copied, l);
1420 copied += l;
1421 if (copied == desc->elem_size)
1422 copied = 0;
1423 } else {
1424 memcpy(elem + copied, c, l);
1425 copied += l;
1426 if (copied == desc->elem_size) {
1427 err = desc->xcode(desc, elem);
1428 if (err)
1429 goto out;
1430 copied = 0;
1431 }
1432 }
1433 }
1434 if (avail_here) {
1435 kunmap(*ppages);
1436 ppages++;
1437 c = kmap(*ppages);
1438 }
1439
1440 avail_page = min(avail_here,
1441 (unsigned int) PAGE_SIZE);
1442 }
1443 base = buf->page_len; /* align to start of tail */
1444 }
1445
1446 /* process tail */
1447 base -= buf->page_len;
1448 if (todo) {
1449 c = buf->tail->iov_base + base;
1450 if (copied) {
1451 unsigned int l = desc->elem_size - copied;
1452
1453 if (encode)
1454 memcpy(c, elem + copied, l);
1455 else {
1456 memcpy(elem + copied, c, l);
1457 err = desc->xcode(desc, elem);
1458 if (err)
1459 goto out;
1460 }
1461 todo -= l;
1462 c += l;
1463 }
1464 while (todo) {
1465 err = desc->xcode(desc, c);
1466 if (err)
1467 goto out;
1468 c += desc->elem_size;
1469 todo -= desc->elem_size;
1470 }
1471 }
1472 err = 0;
1473
1474 out:
1475 kfree(elem);
1476 if (ppages)
1477 kunmap(*ppages);
1478 return err;
1479 }
1480
1481 int
1482 xdr_decode_array2(struct xdr_buf *buf, unsigned int base,
1483 struct xdr_array2_desc *desc)
1484 {
1485 if (base >= buf->len)
1486 return -EINVAL;
1487
1488 return xdr_xcode_array2(buf, base, desc, 0);
1489 }
1490 EXPORT_SYMBOL_GPL(xdr_decode_array2);
1491
1492 int
1493 xdr_encode_array2(struct xdr_buf *buf, unsigned int base,
1494 struct xdr_array2_desc *desc)
1495 {
1496 if ((unsigned long) base + 4 + desc->array_len * desc->elem_size >
1497 buf->head->iov_len + buf->page_len + buf->tail->iov_len)
1498 return -EINVAL;
1499
1500 return xdr_xcode_array2(buf, base, desc, 1);
1501 }
1502 EXPORT_SYMBOL_GPL(xdr_encode_array2);
1503
1504 int
1505 xdr_process_buf(struct xdr_buf *buf, unsigned int offset, unsigned int len,
1506 int (*actor)(struct scatterlist *, void *), void *data)
1507 {
1508 int i, ret = 0;
1509 unsigned int page_len, thislen, page_offset;
1510 struct scatterlist sg[1];
1511
1512 sg_init_table(sg, 1);
1513
1514 if (offset >= buf->head[0].iov_len) {
1515 offset -= buf->head[0].iov_len;
1516 } else {
1517 thislen = buf->head[0].iov_len - offset;
1518 if (thislen > len)
1519 thislen = len;
1520 sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
1521 ret = actor(sg, data);
1522 if (ret)
1523 goto out;
1524 offset = 0;
1525 len -= thislen;
1526 }
1527 if (len == 0)
1528 goto out;
1529
1530 if (offset >= buf->page_len) {
1531 offset -= buf->page_len;
1532 } else {
1533 page_len = buf->page_len - offset;
1534 if (page_len > len)
1535 page_len = len;
1536 len -= page_len;
1537 page_offset = (offset + buf->page_base) & (PAGE_SIZE - 1);
1538 i = (offset + buf->page_base) >> PAGE_SHIFT;
1539 thislen = PAGE_SIZE - page_offset;
1540 do {
1541 if (thislen > page_len)
1542 thislen = page_len;
1543 sg_set_page(sg, buf->pages[i], thislen, page_offset);
1544 ret = actor(sg, data);
1545 if (ret)
1546 goto out;
1547 page_len -= thislen;
1548 i++;
1549 page_offset = 0;
1550 thislen = PAGE_SIZE;
1551 } while (page_len != 0);
1552 offset = 0;
1553 }
1554 if (len == 0)
1555 goto out;
1556 if (offset < buf->tail[0].iov_len) {
1557 thislen = buf->tail[0].iov_len - offset;
1558 if (thislen > len)
1559 thislen = len;
1560 sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
1561 ret = actor(sg, data);
1562 len -= thislen;
1563 }
1564 if (len != 0)
1565 ret = -EINVAL;
1566 out:
1567 return ret;
1568 }
1569 EXPORT_SYMBOL_GPL(xdr_process_buf);
1570
1571 /**
1572 * xdr_stream_decode_opaque - Decode variable length opaque
1573 * @xdr: pointer to xdr_stream
1574 * @ptr: location to store opaque data
1575 * @size: size of storage buffer @ptr
1576 *
1577 * Return values:
1578 * On success, returns size of object stored in *@ptr
1579 * %-EBADMSG on XDR buffer overflow
1580 * %-EMSGSIZE on overflow of storage buffer @ptr
1581 */
1582 ssize_t xdr_stream_decode_opaque(struct xdr_stream *xdr, void *ptr, size_t size)
1583 {
1584 ssize_t ret;
1585 void *p;
1586
1587 ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
1588 if (ret <= 0)
1589 return ret;
1590 memcpy(ptr, p, ret);
1591 return ret;
1592 }
1593 EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque);
1594
1595 /**
1596 * xdr_stream_decode_opaque_dup - Decode and duplicate variable length opaque
1597 * @xdr: pointer to xdr_stream
1598 * @ptr: location to store pointer to opaque data
1599 * @maxlen: maximum acceptable object size
1600 * @gfp_flags: GFP mask to use
1601 *
1602 * Return values:
1603 * On success, returns size of object stored in *@ptr
1604 * %-EBADMSG on XDR buffer overflow
1605 * %-EMSGSIZE if the size of the object would exceed @maxlen
1606 * %-ENOMEM on memory allocation failure
1607 */
1608 ssize_t xdr_stream_decode_opaque_dup(struct xdr_stream *xdr, void **ptr,
1609 size_t maxlen, gfp_t gfp_flags)
1610 {
1611 ssize_t ret;
1612 void *p;
1613
1614 ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
1615 if (ret > 0) {
1616 *ptr = kmemdup(p, ret, gfp_flags);
1617 if (*ptr != NULL)
1618 return ret;
1619 ret = -ENOMEM;
1620 }
1621 *ptr = NULL;
1622 return ret;
1623 }
1624 EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque_dup);
1625
1626 /**
1627 * xdr_stream_decode_string - Decode variable length string
1628 * @xdr: pointer to xdr_stream
1629 * @str: location to store string
1630 * @size: size of storage buffer @str
1631 *
1632 * Return values:
1633 * On success, returns length of NUL-terminated string stored in *@str
1634 * %-EBADMSG on XDR buffer overflow
1635 * %-EMSGSIZE on overflow of storage buffer @str
1636 */
1637 ssize_t xdr_stream_decode_string(struct xdr_stream *xdr, char *str, size_t size)
1638 {
1639 ssize_t ret;
1640 void *p;
1641
1642 ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
1643 if (ret > 0) {
1644 memcpy(str, p, ret);
1645 str[ret] = '\0';
1646 return strlen(str);
1647 }
1648 *str = '\0';
1649 return ret;
1650 }
1651 EXPORT_SYMBOL_GPL(xdr_stream_decode_string);
1652
1653 /**
1654 * xdr_stream_decode_string_dup - Decode and duplicate variable length string
1655 * @xdr: pointer to xdr_stream
1656 * @str: location to store pointer to string
1657 * @maxlen: maximum acceptable string length
1658 * @gfp_flags: GFP mask to use
1659 *
1660 * Return values:
1661 * On success, returns length of NUL-terminated string stored in *@ptr
1662 * %-EBADMSG on XDR buffer overflow
1663 * %-EMSGSIZE if the size of the string would exceed @maxlen
1664 * %-ENOMEM on memory allocation failure
1665 */
1666 ssize_t xdr_stream_decode_string_dup(struct xdr_stream *xdr, char **str,
1667 size_t maxlen, gfp_t gfp_flags)
1668 {
1669 void *p;
1670 ssize_t ret;
1671
1672 ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
1673 if (ret > 0) {
1674 char *s = kmalloc(ret + 1, gfp_flags);
1675 if (s != NULL) {
1676 memcpy(s, p, ret);
1677 s[ret] = '\0';
1678 *str = s;
1679 return strlen(s);
1680 }
1681 ret = -ENOMEM;
1682 }
1683 *str = NULL;
1684 return ret;
1685 }
1686 EXPORT_SYMBOL_GPL(xdr_stream_decode_string_dup);
1687
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