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