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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
778static void xdr_buf_head_shift_left(const struct xdr_buf *buf,
779 unsigned int base, unsigned int len,
780 unsigned int shift)
781{
782 const struct kvec *head = buf->head;
783 unsigned int bytes;
784
785 if (!shift || !len)
786 return;
787
788 if (shift > base) {
789 bytes = (shift - base);
790 if (bytes >= len)
791 return;
792 base += bytes;
793 len -= bytes;
794 }
795
796 if (base < head->iov_len) {
797 bytes = min_t(unsigned int, len, head->iov_len - base);
798 memmove(head->iov_base + (base - shift),
799 head->iov_base + base, bytes);
800 base += bytes;
801 len -= bytes;
802 }
803 xdr_buf_pages_shift_left(buf, base - head->iov_len, len, shift);
804}
805
806/**
807 * xdr_shrink_bufhead
808 * @buf: xdr_buf
809 * @len: new length of buf->head[0]
810 *
811 * Shrinks XDR buffer's header kvec buf->head[0], setting it to
812 * 'len' bytes. The extra data is not lost, but is instead
813 * moved into the inlined pages and/or the tail.
814 */
815static unsigned int xdr_shrink_bufhead(struct xdr_buf *buf, unsigned int len)
816{
817 struct kvec *head = buf->head;
818 unsigned int shift, buflen = max(buf->len, len);
819
820 WARN_ON_ONCE(len > head->iov_len);
821 if (head->iov_len > buflen) {
822 buf->buflen -= head->iov_len - buflen;
823 head->iov_len = buflen;
824 }
825 if (len >= head->iov_len)
826 return 0;
827 shift = head->iov_len - len;
828 xdr_buf_try_expand(buf, shift);
829 xdr_buf_head_shift_right(buf, len, buflen - len, shift);
830 head->iov_len = len;
831 buf->buflen -= shift;
832 buf->len -= shift;
833 return shift;
834}
835
836/**
837 * xdr_shrink_pagelen - shrinks buf->pages to @len bytes
838 * @buf: xdr_buf
839 * @len: new page buffer length
840 *
841 * The extra data is not lost, but is instead moved into buf->tail.
842 * Returns the actual number of bytes moved.
843 */
844static unsigned int xdr_shrink_pagelen(struct xdr_buf *buf, unsigned int len)
845{
846 unsigned int shift, buflen = buf->len - buf->head->iov_len;
847
848 WARN_ON_ONCE(len > buf->page_len);
849 if (buf->head->iov_len >= buf->len || len > buflen)
850 buflen = len;
851 if (buf->page_len > buflen) {
852 buf->buflen -= buf->page_len - buflen;
853 buf->page_len = buflen;
854 }
855 if (len >= buf->page_len)
856 return 0;
857 shift = buf->page_len - len;
858 xdr_buf_try_expand(buf, shift);
859 xdr_buf_pages_shift_right(buf, len, buflen - len, shift);
860 buf->page_len = len;
861 buf->len -= shift;
862 buf->buflen -= shift;
863 return shift;
864}
865
866void
867xdr_shift_buf(struct xdr_buf *buf, size_t len)
868{
869 xdr_shrink_bufhead(buf, buf->head->iov_len - len);
870}
871EXPORT_SYMBOL_GPL(xdr_shift_buf);
872
873/**
874 * xdr_stream_pos - Return the current offset from the start of the xdr_stream
875 * @xdr: pointer to struct xdr_stream
876 */
877unsigned int xdr_stream_pos(const struct xdr_stream *xdr)
878{
879 return (unsigned int)(XDR_QUADLEN(xdr->buf->len) - xdr->nwords) << 2;
880}
881EXPORT_SYMBOL_GPL(xdr_stream_pos);
882
883static void xdr_stream_set_pos(struct xdr_stream *xdr, unsigned int pos)
884{
885 unsigned int blen = xdr->buf->len;
886
887 xdr->nwords = blen > pos ? XDR_QUADLEN(blen) - XDR_QUADLEN(pos) : 0;
888}
889
890static void xdr_stream_page_set_pos(struct xdr_stream *xdr, unsigned int pos)
891{
892 xdr_stream_set_pos(xdr, pos + xdr->buf->head[0].iov_len);
893}
894
895/**
896 * xdr_page_pos - Return the current offset from the start of the xdr pages
897 * @xdr: pointer to struct xdr_stream
898 */
899unsigned int xdr_page_pos(const struct xdr_stream *xdr)
900{
901 unsigned int pos = xdr_stream_pos(xdr);
902
903 WARN_ON(pos < xdr->buf->head[0].iov_len);
904 return pos - xdr->buf->head[0].iov_len;
905}
906EXPORT_SYMBOL_GPL(xdr_page_pos);
907
908/**
909 * xdr_init_encode - Initialize a struct xdr_stream for sending data.
910 * @xdr: pointer to xdr_stream struct
911 * @buf: pointer to XDR buffer in which to encode data
912 * @p: current pointer inside XDR buffer
913 * @rqst: pointer to controlling rpc_rqst, for debugging
914 *
915 * Note: at the moment the RPC client only passes the length of our
916 * scratch buffer in the xdr_buf's header kvec. Previously this
917 * meant we needed to call xdr_adjust_iovec() after encoding the
918 * data. With the new scheme, the xdr_stream manages the details
919 * of the buffer length, and takes care of adjusting the kvec
920 * length for us.
921 */
922void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
923 struct rpc_rqst *rqst)
924{
925 struct kvec *iov = buf->head;
926 int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len;
927
928 xdr_reset_scratch_buffer(xdr);
929 BUG_ON(scratch_len < 0);
930 xdr->buf = buf;
931 xdr->iov = iov;
932 xdr->p = (__be32 *)((char *)iov->iov_base + iov->iov_len);
933 xdr->end = (__be32 *)((char *)iov->iov_base + scratch_len);
934 BUG_ON(iov->iov_len > scratch_len);
935
936 if (p != xdr->p && p != NULL) {
937 size_t len;
938
939 BUG_ON(p < xdr->p || p > xdr->end);
940 len = (char *)p - (char *)xdr->p;
941 xdr->p = p;
942 buf->len += len;
943 iov->iov_len += len;
944 }
945 xdr->rqst = rqst;
946}
947EXPORT_SYMBOL_GPL(xdr_init_encode);
948
949/**
950 * xdr_init_encode_pages - Initialize an xdr_stream for encoding into pages
951 * @xdr: pointer to xdr_stream struct
952 * @buf: pointer to XDR buffer into which to encode data
953 * @pages: list of pages to decode into
954 * @rqst: pointer to controlling rpc_rqst, for debugging
955 *
956 */
957void xdr_init_encode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
958 struct page **pages, struct rpc_rqst *rqst)
959{
960 xdr_reset_scratch_buffer(xdr);
961
962 xdr->buf = buf;
963 xdr->page_ptr = pages;
964 xdr->iov = NULL;
965 xdr->p = page_address(*pages);
966 xdr->end = (void *)xdr->p + min_t(u32, buf->buflen, PAGE_SIZE);
967 xdr->rqst = rqst;
968}
969EXPORT_SYMBOL_GPL(xdr_init_encode_pages);
970
971/**
972 * __xdr_commit_encode - Ensure all data is written to buffer
973 * @xdr: pointer to xdr_stream
974 *
975 * We handle encoding across page boundaries by giving the caller a
976 * temporary location to write to, then later copying the data into
977 * place; xdr_commit_encode does that copying.
978 *
979 * Normally the caller doesn't need to call this directly, as the
980 * following xdr_reserve_space will do it. But an explicit call may be
981 * required at the end of encoding, or any other time when the xdr_buf
982 * data might be read.
983 */
984void __xdr_commit_encode(struct xdr_stream *xdr)
985{
986 size_t shift = xdr->scratch.iov_len;
987 void *page;
988
989 page = page_address(*xdr->page_ptr);
990 memcpy(xdr->scratch.iov_base, page, shift);
991 memmove(page, page + shift, (void *)xdr->p - page);
992 xdr_reset_scratch_buffer(xdr);
993}
994EXPORT_SYMBOL_GPL(__xdr_commit_encode);
995
996/*
997 * The buffer space to be reserved crosses the boundary between
998 * xdr->buf->head and xdr->buf->pages, or between two pages
999 * in xdr->buf->pages.
1000 */
1001static noinline __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr,
1002 size_t nbytes)
1003{
1004 int space_left;
1005 int frag1bytes, frag2bytes;
1006 void *p;
1007
1008 if (nbytes > PAGE_SIZE)
1009 goto out_overflow; /* Bigger buffers require special handling */
1010 if (xdr->buf->len + nbytes > xdr->buf->buflen)
1011 goto out_overflow; /* Sorry, we're totally out of space */
1012 frag1bytes = (xdr->end - xdr->p) << 2;
1013 frag2bytes = nbytes - frag1bytes;
1014 if (xdr->iov)
1015 xdr->iov->iov_len += frag1bytes;
1016 else
1017 xdr->buf->page_len += frag1bytes;
1018 xdr->page_ptr++;
1019 xdr->iov = NULL;
1020
1021 /*
1022 * If the last encode didn't end exactly on a page boundary, the
1023 * next one will straddle boundaries. Encode into the next
1024 * page, then copy it back later in xdr_commit_encode. We use
1025 * the "scratch" iov to track any temporarily unused fragment of
1026 * space at the end of the previous buffer:
1027 */
1028 xdr_set_scratch_buffer(xdr, xdr->p, frag1bytes);
1029
1030 /*
1031 * xdr->p is where the next encode will start after
1032 * xdr_commit_encode() has shifted this one back:
1033 */
1034 p = page_address(*xdr->page_ptr);
1035 xdr->p = p + frag2bytes;
1036 space_left = xdr->buf->buflen - xdr->buf->len;
1037 if (space_left - frag1bytes >= PAGE_SIZE)
1038 xdr->end = p + PAGE_SIZE;
1039 else
1040 xdr->end = p + space_left - frag1bytes;
1041
1042 xdr->buf->page_len += frag2bytes;
1043 xdr->buf->len += nbytes;
1044 return p;
1045out_overflow:
1046 trace_rpc_xdr_overflow(xdr, nbytes);
1047 return NULL;
1048}
1049
1050/**
1051 * xdr_reserve_space - Reserve buffer space for sending
1052 * @xdr: pointer to xdr_stream
1053 * @nbytes: number of bytes to reserve
1054 *
1055 * Checks that we have enough buffer space to encode 'nbytes' more
1056 * bytes of data. If so, update the total xdr_buf length, and
1057 * adjust the length of the current kvec.
1058 */
1059__be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
1060{
1061 __be32 *p = xdr->p;
1062 __be32 *q;
1063
1064 xdr_commit_encode(xdr);
1065 /* align nbytes on the next 32-bit boundary */
1066 nbytes += 3;
1067 nbytes &= ~3;
1068 q = p + (nbytes >> 2);
1069 if (unlikely(q > xdr->end || q < p))
1070 return xdr_get_next_encode_buffer(xdr, nbytes);
1071 xdr->p = q;
1072 if (xdr->iov)
1073 xdr->iov->iov_len += nbytes;
1074 else
1075 xdr->buf->page_len += nbytes;
1076 xdr->buf->len += nbytes;
1077 return p;
1078}
1079EXPORT_SYMBOL_GPL(xdr_reserve_space);
1080
1081
1082/**
1083 * xdr_reserve_space_vec - Reserves a large amount of buffer space for sending
1084 * @xdr: pointer to xdr_stream
1085 * @vec: pointer to a kvec array
1086 * @nbytes: number of bytes to reserve
1087 *
1088 * Reserves enough buffer space to encode 'nbytes' of data and stores the
1089 * pointers in 'vec'. The size argument passed to xdr_reserve_space() is
1090 * determined based on the number of bytes remaining in the current page to
1091 * avoid invalidating iov_base pointers when xdr_commit_encode() is called.
1092 */
1093int xdr_reserve_space_vec(struct xdr_stream *xdr, struct kvec *vec, size_t nbytes)
1094{
1095 int thislen;
1096 int v = 0;
1097 __be32 *p;
1098
1099 /*
1100 * svcrdma requires every READ payload to start somewhere
1101 * in xdr->pages.
1102 */
1103 if (xdr->iov == xdr->buf->head) {
1104 xdr->iov = NULL;
1105 xdr->end = xdr->p;
1106 }
1107
1108 while (nbytes) {
1109 thislen = xdr->buf->page_len % PAGE_SIZE;
1110 thislen = min_t(size_t, nbytes, PAGE_SIZE - thislen);
1111
1112 p = xdr_reserve_space(xdr, thislen);
1113 if (!p)
1114 return -EIO;
1115
1116 vec[v].iov_base = p;
1117 vec[v].iov_len = thislen;
1118 v++;
1119 nbytes -= thislen;
1120 }
1121
1122 return v;
1123}
1124EXPORT_SYMBOL_GPL(xdr_reserve_space_vec);
1125
1126/**
1127 * xdr_truncate_encode - truncate an encode buffer
1128 * @xdr: pointer to xdr_stream
1129 * @len: new length of buffer
1130 *
1131 * Truncates the xdr stream, so that xdr->buf->len == len,
1132 * and xdr->p points at offset len from the start of the buffer, and
1133 * head, tail, and page lengths are adjusted to correspond.
1134 *
1135 * If this means moving xdr->p to a different buffer, we assume that
1136 * the end pointer should be set to the end of the current page,
1137 * except in the case of the head buffer when we assume the head
1138 * buffer's current length represents the end of the available buffer.
1139 *
1140 * This is *not* safe to use on a buffer that already has inlined page
1141 * cache pages (as in a zero-copy server read reply), except for the
1142 * simple case of truncating from one position in the tail to another.
1143 *
1144 */
1145void xdr_truncate_encode(struct xdr_stream *xdr, size_t len)
1146{
1147 struct xdr_buf *buf = xdr->buf;
1148 struct kvec *head = buf->head;
1149 struct kvec *tail = buf->tail;
1150 int fraglen;
1151 int new;
1152
1153 if (len > buf->len) {
1154 WARN_ON_ONCE(1);
1155 return;
1156 }
1157 xdr_commit_encode(xdr);
1158
1159 fraglen = min_t(int, buf->len - len, tail->iov_len);
1160 tail->iov_len -= fraglen;
1161 buf->len -= fraglen;
1162 if (tail->iov_len) {
1163 xdr->p = tail->iov_base + tail->iov_len;
1164 WARN_ON_ONCE(!xdr->end);
1165 WARN_ON_ONCE(!xdr->iov);
1166 return;
1167 }
1168 WARN_ON_ONCE(fraglen);
1169 fraglen = min_t(int, buf->len - len, buf->page_len);
1170 buf->page_len -= fraglen;
1171 buf->len -= fraglen;
1172
1173 new = buf->page_base + buf->page_len;
1174
1175 xdr->page_ptr = buf->pages + (new >> PAGE_SHIFT);
1176
1177 if (buf->page_len) {
1178 xdr->p = page_address(*xdr->page_ptr);
1179 xdr->end = (void *)xdr->p + PAGE_SIZE;
1180 xdr->p = (void *)xdr->p + (new % PAGE_SIZE);
1181 WARN_ON_ONCE(xdr->iov);
1182 return;
1183 }
1184 if (fraglen)
1185 xdr->end = head->iov_base + head->iov_len;
1186 /* (otherwise assume xdr->end is already set) */
1187 xdr->page_ptr--;
1188 head->iov_len = len;
1189 buf->len = len;
1190 xdr->p = head->iov_base + head->iov_len;
1191 xdr->iov = buf->head;
1192}
1193EXPORT_SYMBOL(xdr_truncate_encode);
1194
1195/**
1196 * xdr_restrict_buflen - decrease available buffer space
1197 * @xdr: pointer to xdr_stream
1198 * @newbuflen: new maximum number of bytes available
1199 *
1200 * Adjust our idea of how much space is available in the buffer.
1201 * If we've already used too much space in the buffer, returns -1.
1202 * If the available space is already smaller than newbuflen, returns 0
1203 * and does nothing. Otherwise, adjusts xdr->buf->buflen to newbuflen
1204 * and ensures xdr->end is set at most offset newbuflen from the start
1205 * of the buffer.
1206 */
1207int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen)
1208{
1209 struct xdr_buf *buf = xdr->buf;
1210 int left_in_this_buf = (void *)xdr->end - (void *)xdr->p;
1211 int end_offset = buf->len + left_in_this_buf;
1212
1213 if (newbuflen < 0 || newbuflen < buf->len)
1214 return -1;
1215 if (newbuflen > buf->buflen)
1216 return 0;
1217 if (newbuflen < end_offset)
1218 xdr->end = (void *)xdr->end + newbuflen - end_offset;
1219 buf->buflen = newbuflen;
1220 return 0;
1221}
1222EXPORT_SYMBOL(xdr_restrict_buflen);
1223
1224/**
1225 * xdr_write_pages - Insert a list of pages into an XDR buffer for sending
1226 * @xdr: pointer to xdr_stream
1227 * @pages: array of pages to insert
1228 * @base: starting offset of first data byte in @pages
1229 * @len: number of data bytes in @pages to insert
1230 *
1231 * After the @pages are added, the tail iovec is instantiated pointing to
1232 * end of the head buffer, and the stream is set up to encode subsequent
1233 * items into the tail.
1234 */
1235void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base,
1236 unsigned int len)
1237{
1238 struct xdr_buf *buf = xdr->buf;
1239 struct kvec *tail = buf->tail;
1240
1241 buf->pages = pages;
1242 buf->page_base = base;
1243 buf->page_len = len;
1244
1245 tail->iov_base = xdr->p;
1246 tail->iov_len = 0;
1247 xdr->iov = tail;
1248
1249 if (len & 3) {
1250 unsigned int pad = 4 - (len & 3);
1251
1252 BUG_ON(xdr->p >= xdr->end);
1253 tail->iov_base = (char *)xdr->p + (len & 3);
1254 tail->iov_len += pad;
1255 len += pad;
1256 *xdr->p++ = 0;
1257 }
1258 buf->buflen += len;
1259 buf->len += len;
1260}
1261EXPORT_SYMBOL_GPL(xdr_write_pages);
1262
1263static unsigned int xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
1264 unsigned int base, unsigned int len)
1265{
1266 if (len > iov->iov_len)
1267 len = iov->iov_len;
1268 if (unlikely(base > len))
1269 base = len;
1270 xdr->p = (__be32*)(iov->iov_base + base);
1271 xdr->end = (__be32*)(iov->iov_base + len);
1272 xdr->iov = iov;
1273 xdr->page_ptr = NULL;
1274 return len - base;
1275}
1276
1277static unsigned int xdr_set_tail_base(struct xdr_stream *xdr,
1278 unsigned int base, unsigned int len)
1279{
1280 struct xdr_buf *buf = xdr->buf;
1281
1282 xdr_stream_set_pos(xdr, base + buf->page_len + buf->head->iov_len);
1283 return xdr_set_iov(xdr, buf->tail, base, len);
1284}
1285
1286static unsigned int xdr_set_page_base(struct xdr_stream *xdr,
1287 unsigned int base, unsigned int len)
1288{
1289 unsigned int pgnr;
1290 unsigned int maxlen;
1291 unsigned int pgoff;
1292 unsigned int pgend;
1293 void *kaddr;
1294
1295 maxlen = xdr->buf->page_len;
1296 if (base >= maxlen)
1297 return 0;
1298 else
1299 maxlen -= base;
1300 if (len > maxlen)
1301 len = maxlen;
1302
1303 xdr_stream_page_set_pos(xdr, base);
1304 base += xdr->buf->page_base;
1305
1306 pgnr = base >> PAGE_SHIFT;
1307 xdr->page_ptr = &xdr->buf->pages[pgnr];
1308 kaddr = page_address(*xdr->page_ptr);
1309
1310 pgoff = base & ~PAGE_MASK;
1311 xdr->p = (__be32*)(kaddr + pgoff);
1312
1313 pgend = pgoff + len;
1314 if (pgend > PAGE_SIZE)
1315 pgend = PAGE_SIZE;
1316 xdr->end = (__be32*)(kaddr + pgend);
1317 xdr->iov = NULL;
1318 return len;
1319}
1320
1321static void xdr_set_page(struct xdr_stream *xdr, unsigned int base,
1322 unsigned int len)
1323{
1324 if (xdr_set_page_base(xdr, base, len) == 0) {
1325 base -= xdr->buf->page_len;
1326 xdr_set_tail_base(xdr, base, len);
1327 }
1328}
1329
1330static void xdr_set_next_page(struct xdr_stream *xdr)
1331{
1332 unsigned int newbase;
1333
1334 newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT;
1335 newbase -= xdr->buf->page_base;
1336 if (newbase < xdr->buf->page_len)
1337 xdr_set_page_base(xdr, newbase, xdr_stream_remaining(xdr));
1338 else
1339 xdr_set_tail_base(xdr, 0, xdr_stream_remaining(xdr));
1340}
1341
1342static bool xdr_set_next_buffer(struct xdr_stream *xdr)
1343{
1344 if (xdr->page_ptr != NULL)
1345 xdr_set_next_page(xdr);
1346 else if (xdr->iov == xdr->buf->head)
1347 xdr_set_page(xdr, 0, xdr_stream_remaining(xdr));
1348 return xdr->p != xdr->end;
1349}
1350
1351/**
1352 * xdr_init_decode - Initialize an xdr_stream for decoding data.
1353 * @xdr: pointer to xdr_stream struct
1354 * @buf: pointer to XDR buffer from which to decode data
1355 * @p: current pointer inside XDR buffer
1356 * @rqst: pointer to controlling rpc_rqst, for debugging
1357 */
1358void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
1359 struct rpc_rqst *rqst)
1360{
1361 xdr->buf = buf;
1362 xdr_reset_scratch_buffer(xdr);
1363 xdr->nwords = XDR_QUADLEN(buf->len);
1364 if (xdr_set_iov(xdr, buf->head, 0, buf->len) == 0 &&
1365 xdr_set_page_base(xdr, 0, buf->len) == 0)
1366 xdr_set_iov(xdr, buf->tail, 0, buf->len);
1367 if (p != NULL && p > xdr->p && xdr->end >= p) {
1368 xdr->nwords -= p - xdr->p;
1369 xdr->p = p;
1370 }
1371 xdr->rqst = rqst;
1372}
1373EXPORT_SYMBOL_GPL(xdr_init_decode);
1374
1375/**
1376 * xdr_init_decode_pages - Initialize an xdr_stream for decoding into pages
1377 * @xdr: pointer to xdr_stream struct
1378 * @buf: pointer to XDR buffer from which to decode data
1379 * @pages: list of pages to decode into
1380 * @len: length in bytes of buffer in pages
1381 */
1382void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
1383 struct page **pages, unsigned int len)
1384{
1385 memset(buf, 0, sizeof(*buf));
1386 buf->pages = pages;
1387 buf->page_len = len;
1388 buf->buflen = len;
1389 buf->len = len;
1390 xdr_init_decode(xdr, buf, NULL, NULL);
1391}
1392EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
1393
1394static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
1395{
1396 unsigned int nwords = XDR_QUADLEN(nbytes);
1397 __be32 *p = xdr->p;
1398 __be32 *q = p + nwords;
1399
1400 if (unlikely(nwords > xdr->nwords || q > xdr->end || q < p))
1401 return NULL;
1402 xdr->p = q;
1403 xdr->nwords -= nwords;
1404 return p;
1405}
1406
1407static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes)
1408{
1409 __be32 *p;
1410 char *cpdest = xdr->scratch.iov_base;
1411 size_t cplen = (char *)xdr->end - (char *)xdr->p;
1412
1413 if (nbytes > xdr->scratch.iov_len)
1414 goto out_overflow;
1415 p = __xdr_inline_decode(xdr, cplen);
1416 if (p == NULL)
1417 return NULL;
1418 memcpy(cpdest, p, cplen);
1419 if (!xdr_set_next_buffer(xdr))
1420 goto out_overflow;
1421 cpdest += cplen;
1422 nbytes -= cplen;
1423 p = __xdr_inline_decode(xdr, nbytes);
1424 if (p == NULL)
1425 return NULL;
1426 memcpy(cpdest, p, nbytes);
1427 return xdr->scratch.iov_base;
1428out_overflow:
1429 trace_rpc_xdr_overflow(xdr, nbytes);
1430 return NULL;
1431}
1432
1433/**
1434 * xdr_inline_decode - Retrieve XDR data to decode
1435 * @xdr: pointer to xdr_stream struct
1436 * @nbytes: number of bytes of data to decode
1437 *
1438 * Check if the input buffer is long enough to enable us to decode
1439 * 'nbytes' more bytes of data starting at the current position.
1440 * If so return the current pointer, then update the current
1441 * pointer position.
1442 */
1443__be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
1444{
1445 __be32 *p;
1446
1447 if (unlikely(nbytes == 0))
1448 return xdr->p;
1449 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
1450 goto out_overflow;
1451 p = __xdr_inline_decode(xdr, nbytes);
1452 if (p != NULL)
1453 return p;
1454 return xdr_copy_to_scratch(xdr, nbytes);
1455out_overflow:
1456 trace_rpc_xdr_overflow(xdr, nbytes);
1457 return NULL;
1458}
1459EXPORT_SYMBOL_GPL(xdr_inline_decode);
1460
1461static void xdr_realign_pages(struct xdr_stream *xdr)
1462{
1463 struct xdr_buf *buf = xdr->buf;
1464 struct kvec *iov = buf->head;
1465 unsigned int cur = xdr_stream_pos(xdr);
1466 unsigned int copied;
1467
1468 /* Realign pages to current pointer position */
1469 if (iov->iov_len > cur) {
1470 copied = xdr_shrink_bufhead(buf, cur);
1471 trace_rpc_xdr_alignment(xdr, cur, copied);
1472 xdr_set_page(xdr, 0, buf->page_len);
1473 }
1474}
1475
1476static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len)
1477{
1478 struct xdr_buf *buf = xdr->buf;
1479 unsigned int nwords = XDR_QUADLEN(len);
1480 unsigned int copied;
1481
1482 if (xdr->nwords == 0)
1483 return 0;
1484
1485 xdr_realign_pages(xdr);
1486 if (nwords > xdr->nwords) {
1487 nwords = xdr->nwords;
1488 len = nwords << 2;
1489 }
1490 if (buf->page_len <= len)
1491 len = buf->page_len;
1492 else if (nwords < xdr->nwords) {
1493 /* Truncate page data and move it into the tail */
1494 copied = xdr_shrink_pagelen(buf, len);
1495 trace_rpc_xdr_alignment(xdr, len, copied);
1496 }
1497 return len;
1498}
1499
1500/**
1501 * xdr_read_pages - align page-based XDR data to current pointer position
1502 * @xdr: pointer to xdr_stream struct
1503 * @len: number of bytes of page data
1504 *
1505 * Moves data beyond the current pointer position from the XDR head[] buffer
1506 * into the page list. Any data that lies beyond current position + @len
1507 * bytes is moved into the XDR tail[]. The xdr_stream current position is
1508 * then advanced past that data to align to the next XDR object in the tail.
1509 *
1510 * Returns the number of XDR encoded bytes now contained in the pages
1511 */
1512unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
1513{
1514 unsigned int nwords = XDR_QUADLEN(len);
1515 unsigned int base, end, pglen;
1516
1517 pglen = xdr_align_pages(xdr, nwords << 2);
1518 if (pglen == 0)
1519 return 0;
1520
1521 base = (nwords << 2) - pglen;
1522 end = xdr_stream_remaining(xdr) - pglen;
1523
1524 xdr_set_tail_base(xdr, base, end);
1525 return len <= pglen ? len : pglen;
1526}
1527EXPORT_SYMBOL_GPL(xdr_read_pages);
1528
1529/**
1530 * xdr_set_pagelen - Sets the length of the XDR pages
1531 * @xdr: pointer to xdr_stream struct
1532 * @len: new length of the XDR page data
1533 *
1534 * Either grows or shrinks the length of the xdr pages by setting pagelen to
1535 * @len bytes. When shrinking, any extra data is moved into buf->tail, whereas
1536 * when growing any data beyond the current pointer is moved into the tail.
1537 *
1538 * Returns True if the operation was successful, and False otherwise.
1539 */
1540void xdr_set_pagelen(struct xdr_stream *xdr, unsigned int len)
1541{
1542 struct xdr_buf *buf = xdr->buf;
1543 size_t remaining = xdr_stream_remaining(xdr);
1544 size_t base = 0;
1545
1546 if (len < buf->page_len) {
1547 base = buf->page_len - len;
1548 xdr_shrink_pagelen(buf, len);
1549 } else {
1550 xdr_buf_head_shift_right(buf, xdr_stream_pos(xdr),
1551 buf->page_len, remaining);
1552 if (len > buf->page_len)
1553 xdr_buf_try_expand(buf, len - buf->page_len);
1554 }
1555 xdr_set_tail_base(xdr, base, remaining);
1556}
1557EXPORT_SYMBOL_GPL(xdr_set_pagelen);
1558
1559/**
1560 * xdr_enter_page - decode data from the XDR page
1561 * @xdr: pointer to xdr_stream struct
1562 * @len: number of bytes of page data
1563 *
1564 * Moves data beyond the current pointer position from the XDR head[] buffer
1565 * into the page list. Any data that lies beyond current position + "len"
1566 * bytes is moved into the XDR tail[]. The current pointer is then
1567 * repositioned at the beginning of the first XDR page.
1568 */
1569void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
1570{
1571 len = xdr_align_pages(xdr, len);
1572 /*
1573 * Position current pointer at beginning of tail, and
1574 * set remaining message length.
1575 */
1576 if (len != 0)
1577 xdr_set_page_base(xdr, 0, len);
1578}
1579EXPORT_SYMBOL_GPL(xdr_enter_page);
1580
1581static const struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0};
1582
1583void xdr_buf_from_iov(const struct kvec *iov, struct xdr_buf *buf)
1584{
1585 buf->head[0] = *iov;
1586 buf->tail[0] = empty_iov;
1587 buf->page_len = 0;
1588 buf->buflen = buf->len = iov->iov_len;
1589}
1590EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
1591
1592/**
1593 * xdr_buf_subsegment - set subbuf to a portion of buf
1594 * @buf: an xdr buffer
1595 * @subbuf: the result buffer
1596 * @base: beginning of range in bytes
1597 * @len: length of range in bytes
1598 *
1599 * sets @subbuf to an xdr buffer representing the portion of @buf of
1600 * length @len starting at offset @base.
1601 *
1602 * @buf and @subbuf may be pointers to the same struct xdr_buf.
1603 *
1604 * Returns -1 if base or length are out of bounds.
1605 */
1606int xdr_buf_subsegment(const struct xdr_buf *buf, struct xdr_buf *subbuf,
1607 unsigned int base, unsigned int len)
1608{
1609 subbuf->buflen = subbuf->len = len;
1610 if (base < buf->head[0].iov_len) {
1611 subbuf->head[0].iov_base = buf->head[0].iov_base + base;
1612 subbuf->head[0].iov_len = min_t(unsigned int, len,
1613 buf->head[0].iov_len - base);
1614 len -= subbuf->head[0].iov_len;
1615 base = 0;
1616 } else {
1617 base -= buf->head[0].iov_len;
1618 subbuf->head[0].iov_base = buf->head[0].iov_base;
1619 subbuf->head[0].iov_len = 0;
1620 }
1621
1622 if (base < buf->page_len) {
1623 subbuf->page_len = min(buf->page_len - base, len);
1624 base += buf->page_base;
1625 subbuf->page_base = base & ~PAGE_MASK;
1626 subbuf->pages = &buf->pages[base >> PAGE_SHIFT];
1627 len -= subbuf->page_len;
1628 base = 0;
1629 } else {
1630 base -= buf->page_len;
1631 subbuf->pages = buf->pages;
1632 subbuf->page_base = 0;
1633 subbuf->page_len = 0;
1634 }
1635
1636 if (base < buf->tail[0].iov_len) {
1637 subbuf->tail[0].iov_base = buf->tail[0].iov_base + base;
1638 subbuf->tail[0].iov_len = min_t(unsigned int, len,
1639 buf->tail[0].iov_len - base);
1640 len -= subbuf->tail[0].iov_len;
1641 base = 0;
1642 } else {
1643 base -= buf->tail[0].iov_len;
1644 subbuf->tail[0].iov_base = buf->tail[0].iov_base;
1645 subbuf->tail[0].iov_len = 0;
1646 }
1647
1648 if (base || len)
1649 return -1;
1650 return 0;
1651}
1652EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
1653
1654/**
1655 * xdr_stream_subsegment - set @subbuf to a portion of @xdr
1656 * @xdr: an xdr_stream set up for decoding
1657 * @subbuf: the result buffer
1658 * @nbytes: length of @xdr to extract, in bytes
1659 *
1660 * Sets up @subbuf to represent a portion of @xdr. The portion
1661 * starts at the current offset in @xdr, and extends for a length
1662 * of @nbytes. If this is successful, @xdr is advanced to the next
1663 * XDR data item following that portion.
1664 *
1665 * Return values:
1666 * %true: @subbuf has been initialized, and @xdr has been advanced.
1667 * %false: a bounds error has occurred
1668 */
1669bool xdr_stream_subsegment(struct xdr_stream *xdr, struct xdr_buf *subbuf,
1670 unsigned int nbytes)
1671{
1672 unsigned int start = xdr_stream_pos(xdr);
1673 unsigned int remaining, len;
1674
1675 /* Extract @subbuf and bounds-check the fn arguments */
1676 if (xdr_buf_subsegment(xdr->buf, subbuf, start, nbytes))
1677 return false;
1678
1679 /* Advance @xdr by @nbytes */
1680 for (remaining = nbytes; remaining;) {
1681 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
1682 return false;
1683
1684 len = (char *)xdr->end - (char *)xdr->p;
1685 if (remaining <= len) {
1686 xdr->p = (__be32 *)((char *)xdr->p +
1687 (remaining + xdr_pad_size(nbytes)));
1688 break;
1689 }
1690
1691 xdr->p = (__be32 *)((char *)xdr->p + len);
1692 xdr->end = xdr->p;
1693 remaining -= len;
1694 }
1695
1696 xdr_stream_set_pos(xdr, start + nbytes);
1697 return true;
1698}
1699EXPORT_SYMBOL_GPL(xdr_stream_subsegment);
1700
1701/**
1702 * xdr_stream_move_subsegment - Move part of a stream to another position
1703 * @xdr: the source xdr_stream
1704 * @offset: the source offset of the segment
1705 * @target: the target offset of the segment
1706 * @length: the number of bytes to move
1707 *
1708 * Moves @length bytes from @offset to @target in the xdr_stream, overwriting
1709 * anything in its space. Returns the number of bytes in the segment.
1710 */
1711unsigned int xdr_stream_move_subsegment(struct xdr_stream *xdr, unsigned int offset,
1712 unsigned int target, unsigned int length)
1713{
1714 struct xdr_buf buf;
1715 unsigned int shift;
1716
1717 if (offset < target) {
1718 shift = target - offset;
1719 if (xdr_buf_subsegment(xdr->buf, &buf, offset, shift + length) < 0)
1720 return 0;
1721 xdr_buf_head_shift_right(&buf, 0, length, shift);
1722 } else if (offset > target) {
1723 shift = offset - target;
1724 if (xdr_buf_subsegment(xdr->buf, &buf, target, shift + length) < 0)
1725 return 0;
1726 xdr_buf_head_shift_left(&buf, shift, length, shift);
1727 }
1728 return length;
1729}
1730EXPORT_SYMBOL_GPL(xdr_stream_move_subsegment);
1731
1732/**
1733 * xdr_stream_zero - zero out a portion of an xdr_stream
1734 * @xdr: an xdr_stream to zero out
1735 * @offset: the starting point in the stream
1736 * @length: the number of bytes to zero
1737 */
1738unsigned int xdr_stream_zero(struct xdr_stream *xdr, unsigned int offset,
1739 unsigned int length)
1740{
1741 struct xdr_buf buf;
1742
1743 if (xdr_buf_subsegment(xdr->buf, &buf, offset, length) < 0)
1744 return 0;
1745 if (buf.head[0].iov_len)
1746 xdr_buf_iov_zero(buf.head, 0, buf.head[0].iov_len);
1747 if (buf.page_len > 0)
1748 xdr_buf_pages_zero(&buf, 0, buf.page_len);
1749 if (buf.tail[0].iov_len)
1750 xdr_buf_iov_zero(buf.tail, 0, buf.tail[0].iov_len);
1751 return length;
1752}
1753EXPORT_SYMBOL_GPL(xdr_stream_zero);
1754
1755/**
1756 * xdr_buf_trim - lop at most "len" bytes off the end of "buf"
1757 * @buf: buf to be trimmed
1758 * @len: number of bytes to reduce "buf" by
1759 *
1760 * Trim an xdr_buf by the given number of bytes by fixing up the lengths. Note
1761 * that it's possible that we'll trim less than that amount if the xdr_buf is
1762 * too small, or if (for instance) it's all in the head and the parser has
1763 * already read too far into it.
1764 */
1765void xdr_buf_trim(struct xdr_buf *buf, unsigned int len)
1766{
1767 size_t cur;
1768 unsigned int trim = len;
1769
1770 if (buf->tail[0].iov_len) {
1771 cur = min_t(size_t, buf->tail[0].iov_len, trim);
1772 buf->tail[0].iov_len -= cur;
1773 trim -= cur;
1774 if (!trim)
1775 goto fix_len;
1776 }
1777
1778 if (buf->page_len) {
1779 cur = min_t(unsigned int, buf->page_len, trim);
1780 buf->page_len -= cur;
1781 trim -= cur;
1782 if (!trim)
1783 goto fix_len;
1784 }
1785
1786 if (buf->head[0].iov_len) {
1787 cur = min_t(size_t, buf->head[0].iov_len, trim);
1788 buf->head[0].iov_len -= cur;
1789 trim -= cur;
1790 }
1791fix_len:
1792 buf->len -= (len - trim);
1793}
1794EXPORT_SYMBOL_GPL(xdr_buf_trim);
1795
1796static void __read_bytes_from_xdr_buf(const struct xdr_buf *subbuf,
1797 void *obj, unsigned int len)
1798{
1799 unsigned int this_len;
1800
1801 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1802 memcpy(obj, subbuf->head[0].iov_base, this_len);
1803 len -= this_len;
1804 obj += this_len;
1805 this_len = min_t(unsigned int, len, subbuf->page_len);
1806 _copy_from_pages(obj, subbuf->pages, subbuf->page_base, this_len);
1807 len -= this_len;
1808 obj += this_len;
1809 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1810 memcpy(obj, subbuf->tail[0].iov_base, this_len);
1811}
1812
1813/* obj is assumed to point to allocated memory of size at least len: */
1814int read_bytes_from_xdr_buf(const struct xdr_buf *buf, unsigned int base,
1815 void *obj, unsigned int len)
1816{
1817 struct xdr_buf subbuf;
1818 int status;
1819
1820 status = xdr_buf_subsegment(buf, &subbuf, base, len);
1821 if (status != 0)
1822 return status;
1823 __read_bytes_from_xdr_buf(&subbuf, obj, len);
1824 return 0;
1825}
1826EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf);
1827
1828static void __write_bytes_to_xdr_buf(const struct xdr_buf *subbuf,
1829 void *obj, unsigned int len)
1830{
1831 unsigned int this_len;
1832
1833 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1834 memcpy(subbuf->head[0].iov_base, obj, this_len);
1835 len -= this_len;
1836 obj += this_len;
1837 this_len = min_t(unsigned int, len, subbuf->page_len);
1838 _copy_to_pages(subbuf->pages, subbuf->page_base, obj, this_len);
1839 len -= this_len;
1840 obj += this_len;
1841 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1842 memcpy(subbuf->tail[0].iov_base, obj, this_len);
1843}
1844
1845/* obj is assumed to point to allocated memory of size at least len: */
1846int write_bytes_to_xdr_buf(const struct xdr_buf *buf, unsigned int base,
1847 void *obj, unsigned int len)
1848{
1849 struct xdr_buf subbuf;
1850 int status;
1851
1852 status = xdr_buf_subsegment(buf, &subbuf, base, len);
1853 if (status != 0)
1854 return status;
1855 __write_bytes_to_xdr_buf(&subbuf, obj, len);
1856 return 0;
1857}
1858EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf);
1859
1860int xdr_decode_word(const struct xdr_buf *buf, unsigned int base, u32 *obj)
1861{
1862 __be32 raw;
1863 int status;
1864
1865 status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
1866 if (status)
1867 return status;
1868 *obj = be32_to_cpu(raw);
1869 return 0;
1870}
1871EXPORT_SYMBOL_GPL(xdr_decode_word);
1872
1873int xdr_encode_word(const struct xdr_buf *buf, unsigned int base, u32 obj)
1874{
1875 __be32 raw = cpu_to_be32(obj);
1876
1877 return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj));
1878}
1879EXPORT_SYMBOL_GPL(xdr_encode_word);
1880
1881/* Returns 0 on success, or else a negative error code. */
1882static int xdr_xcode_array2(const struct xdr_buf *buf, unsigned int base,
1883 struct xdr_array2_desc *desc, int encode)
1884{
1885 char *elem = NULL, *c;
1886 unsigned int copied = 0, todo, avail_here;
1887 struct page **ppages = NULL;
1888 int err;
1889
1890 if (encode) {
1891 if (xdr_encode_word(buf, base, desc->array_len) != 0)
1892 return -EINVAL;
1893 } else {
1894 if (xdr_decode_word(buf, base, &desc->array_len) != 0 ||
1895 desc->array_len > desc->array_maxlen ||
1896 (unsigned long) base + 4 + desc->array_len *
1897 desc->elem_size > buf->len)
1898 return -EINVAL;
1899 }
1900 base += 4;
1901
1902 if (!desc->xcode)
1903 return 0;
1904
1905 todo = desc->array_len * desc->elem_size;
1906
1907 /* process head */
1908 if (todo && base < buf->head->iov_len) {
1909 c = buf->head->iov_base + base;
1910 avail_here = min_t(unsigned int, todo,
1911 buf->head->iov_len - base);
1912 todo -= avail_here;
1913
1914 while (avail_here >= desc->elem_size) {
1915 err = desc->xcode(desc, c);
1916 if (err)
1917 goto out;
1918 c += desc->elem_size;
1919 avail_here -= desc->elem_size;
1920 }
1921 if (avail_here) {
1922 if (!elem) {
1923 elem = kmalloc(desc->elem_size, GFP_KERNEL);
1924 err = -ENOMEM;
1925 if (!elem)
1926 goto out;
1927 }
1928 if (encode) {
1929 err = desc->xcode(desc, elem);
1930 if (err)
1931 goto out;
1932 memcpy(c, elem, avail_here);
1933 } else
1934 memcpy(elem, c, avail_here);
1935 copied = avail_here;
1936 }
1937 base = buf->head->iov_len; /* align to start of pages */
1938 }
1939
1940 /* process pages array */
1941 base -= buf->head->iov_len;
1942 if (todo && base < buf->page_len) {
1943 unsigned int avail_page;
1944
1945 avail_here = min(todo, buf->page_len - base);
1946 todo -= avail_here;
1947
1948 base += buf->page_base;
1949 ppages = buf->pages + (base >> PAGE_SHIFT);
1950 base &= ~PAGE_MASK;
1951 avail_page = min_t(unsigned int, PAGE_SIZE - base,
1952 avail_here);
1953 c = kmap(*ppages) + base;
1954
1955 while (avail_here) {
1956 avail_here -= avail_page;
1957 if (copied || avail_page < desc->elem_size) {
1958 unsigned int l = min(avail_page,
1959 desc->elem_size - copied);
1960 if (!elem) {
1961 elem = kmalloc(desc->elem_size,
1962 GFP_KERNEL);
1963 err = -ENOMEM;
1964 if (!elem)
1965 goto out;
1966 }
1967 if (encode) {
1968 if (!copied) {
1969 err = desc->xcode(desc, elem);
1970 if (err)
1971 goto out;
1972 }
1973 memcpy(c, elem + copied, l);
1974 copied += l;
1975 if (copied == desc->elem_size)
1976 copied = 0;
1977 } else {
1978 memcpy(elem + copied, c, l);
1979 copied += l;
1980 if (copied == desc->elem_size) {
1981 err = desc->xcode(desc, elem);
1982 if (err)
1983 goto out;
1984 copied = 0;
1985 }
1986 }
1987 avail_page -= l;
1988 c += l;
1989 }
1990 while (avail_page >= desc->elem_size) {
1991 err = desc->xcode(desc, c);
1992 if (err)
1993 goto out;
1994 c += desc->elem_size;
1995 avail_page -= desc->elem_size;
1996 }
1997 if (avail_page) {
1998 unsigned int l = min(avail_page,
1999 desc->elem_size - copied);
2000 if (!elem) {
2001 elem = kmalloc(desc->elem_size,
2002 GFP_KERNEL);
2003 err = -ENOMEM;
2004 if (!elem)
2005 goto out;
2006 }
2007 if (encode) {
2008 if (!copied) {
2009 err = desc->xcode(desc, elem);
2010 if (err)
2011 goto out;
2012 }
2013 memcpy(c, elem + copied, l);
2014 copied += l;
2015 if (copied == desc->elem_size)
2016 copied = 0;
2017 } else {
2018 memcpy(elem + copied, c, l);
2019 copied += l;
2020 if (copied == desc->elem_size) {
2021 err = desc->xcode(desc, elem);
2022 if (err)
2023 goto out;
2024 copied = 0;
2025 }
2026 }
2027 }
2028 if (avail_here) {
2029 kunmap(*ppages);
2030 ppages++;
2031 c = kmap(*ppages);
2032 }
2033
2034 avail_page = min(avail_here,
2035 (unsigned int) PAGE_SIZE);
2036 }
2037 base = buf->page_len; /* align to start of tail */
2038 }
2039
2040 /* process tail */
2041 base -= buf->page_len;
2042 if (todo) {
2043 c = buf->tail->iov_base + base;
2044 if (copied) {
2045 unsigned int l = desc->elem_size - copied;
2046
2047 if (encode)
2048 memcpy(c, elem + copied, l);
2049 else {
2050 memcpy(elem + copied, c, l);
2051 err = desc->xcode(desc, elem);
2052 if (err)
2053 goto out;
2054 }
2055 todo -= l;
2056 c += l;
2057 }
2058 while (todo) {
2059 err = desc->xcode(desc, c);
2060 if (err)
2061 goto out;
2062 c += desc->elem_size;
2063 todo -= desc->elem_size;
2064 }
2065 }
2066 err = 0;
2067
2068out:
2069 kfree(elem);
2070 if (ppages)
2071 kunmap(*ppages);
2072 return err;
2073}
2074
2075int xdr_decode_array2(const struct xdr_buf *buf, unsigned int base,
2076 struct xdr_array2_desc *desc)
2077{
2078 if (base >= buf->len)
2079 return -EINVAL;
2080
2081 return xdr_xcode_array2(buf, base, desc, 0);
2082}
2083EXPORT_SYMBOL_GPL(xdr_decode_array2);
2084
2085int xdr_encode_array2(const struct xdr_buf *buf, unsigned int base,
2086 struct xdr_array2_desc *desc)
2087{
2088 if ((unsigned long) base + 4 + desc->array_len * desc->elem_size >
2089 buf->head->iov_len + buf->page_len + buf->tail->iov_len)
2090 return -EINVAL;
2091
2092 return xdr_xcode_array2(buf, base, desc, 1);
2093}
2094EXPORT_SYMBOL_GPL(xdr_encode_array2);
2095
2096int xdr_process_buf(const struct xdr_buf *buf, unsigned int offset,
2097 unsigned int len,
2098 int (*actor)(struct scatterlist *, void *), void *data)
2099{
2100 int i, ret = 0;
2101 unsigned int page_len, thislen, page_offset;
2102 struct scatterlist sg[1];
2103
2104 sg_init_table(sg, 1);
2105
2106 if (offset >= buf->head[0].iov_len) {
2107 offset -= buf->head[0].iov_len;
2108 } else {
2109 thislen = buf->head[0].iov_len - offset;
2110 if (thislen > len)
2111 thislen = len;
2112 sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
2113 ret = actor(sg, data);
2114 if (ret)
2115 goto out;
2116 offset = 0;
2117 len -= thislen;
2118 }
2119 if (len == 0)
2120 goto out;
2121
2122 if (offset >= buf->page_len) {
2123 offset -= buf->page_len;
2124 } else {
2125 page_len = buf->page_len - offset;
2126 if (page_len > len)
2127 page_len = len;
2128 len -= page_len;
2129 page_offset = (offset + buf->page_base) & (PAGE_SIZE - 1);
2130 i = (offset + buf->page_base) >> PAGE_SHIFT;
2131 thislen = PAGE_SIZE - page_offset;
2132 do {
2133 if (thislen > page_len)
2134 thislen = page_len;
2135 sg_set_page(sg, buf->pages[i], thislen, page_offset);
2136 ret = actor(sg, data);
2137 if (ret)
2138 goto out;
2139 page_len -= thislen;
2140 i++;
2141 page_offset = 0;
2142 thislen = PAGE_SIZE;
2143 } while (page_len != 0);
2144 offset = 0;
2145 }
2146 if (len == 0)
2147 goto out;
2148 if (offset < buf->tail[0].iov_len) {
2149 thislen = buf->tail[0].iov_len - offset;
2150 if (thislen > len)
2151 thislen = len;
2152 sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
2153 ret = actor(sg, data);
2154 len -= thislen;
2155 }
2156 if (len != 0)
2157 ret = -EINVAL;
2158out:
2159 return ret;
2160}
2161EXPORT_SYMBOL_GPL(xdr_process_buf);
2162
2163/**
2164 * xdr_stream_decode_opaque - Decode variable length opaque
2165 * @xdr: pointer to xdr_stream
2166 * @ptr: location to store opaque data
2167 * @size: size of storage buffer @ptr
2168 *
2169 * Return values:
2170 * On success, returns size of object stored in *@ptr
2171 * %-EBADMSG on XDR buffer overflow
2172 * %-EMSGSIZE on overflow of storage buffer @ptr
2173 */
2174ssize_t xdr_stream_decode_opaque(struct xdr_stream *xdr, void *ptr, size_t size)
2175{
2176 ssize_t ret;
2177 void *p;
2178
2179 ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
2180 if (ret <= 0)
2181 return ret;
2182 memcpy(ptr, p, ret);
2183 return ret;
2184}
2185EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque);
2186
2187/**
2188 * xdr_stream_decode_opaque_dup - Decode and duplicate variable length opaque
2189 * @xdr: pointer to xdr_stream
2190 * @ptr: location to store pointer to opaque data
2191 * @maxlen: maximum acceptable object size
2192 * @gfp_flags: GFP mask to use
2193 *
2194 * Return values:
2195 * On success, returns size of object stored in *@ptr
2196 * %-EBADMSG on XDR buffer overflow
2197 * %-EMSGSIZE if the size of the object would exceed @maxlen
2198 * %-ENOMEM on memory allocation failure
2199 */
2200ssize_t xdr_stream_decode_opaque_dup(struct xdr_stream *xdr, void **ptr,
2201 size_t maxlen, gfp_t gfp_flags)
2202{
2203 ssize_t ret;
2204 void *p;
2205
2206 ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
2207 if (ret > 0) {
2208 *ptr = kmemdup(p, ret, gfp_flags);
2209 if (*ptr != NULL)
2210 return ret;
2211 ret = -ENOMEM;
2212 }
2213 *ptr = NULL;
2214 return ret;
2215}
2216EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque_dup);
2217
2218/**
2219 * xdr_stream_decode_string - Decode variable length string
2220 * @xdr: pointer to xdr_stream
2221 * @str: location to store string
2222 * @size: size of storage buffer @str
2223 *
2224 * Return values:
2225 * On success, returns length of NUL-terminated string stored in *@str
2226 * %-EBADMSG on XDR buffer overflow
2227 * %-EMSGSIZE on overflow of storage buffer @str
2228 */
2229ssize_t xdr_stream_decode_string(struct xdr_stream *xdr, char *str, size_t size)
2230{
2231 ssize_t ret;
2232 void *p;
2233
2234 ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
2235 if (ret > 0) {
2236 memcpy(str, p, ret);
2237 str[ret] = '\0';
2238 return strlen(str);
2239 }
2240 *str = '\0';
2241 return ret;
2242}
2243EXPORT_SYMBOL_GPL(xdr_stream_decode_string);
2244
2245/**
2246 * xdr_stream_decode_string_dup - Decode and duplicate variable length string
2247 * @xdr: pointer to xdr_stream
2248 * @str: location to store pointer to string
2249 * @maxlen: maximum acceptable string length
2250 * @gfp_flags: GFP mask to use
2251 *
2252 * Return values:
2253 * On success, returns length of NUL-terminated string stored in *@ptr
2254 * %-EBADMSG on XDR buffer overflow
2255 * %-EMSGSIZE if the size of the string would exceed @maxlen
2256 * %-ENOMEM on memory allocation failure
2257 */
2258ssize_t xdr_stream_decode_string_dup(struct xdr_stream *xdr, char **str,
2259 size_t maxlen, gfp_t gfp_flags)
2260{
2261 void *p;
2262 ssize_t ret;
2263
2264 ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
2265 if (ret > 0) {
2266 char *s = kmemdup_nul(p, ret, gfp_flags);
2267 if (s != NULL) {
2268 *str = s;
2269 return strlen(s);
2270 }
2271 ret = -ENOMEM;
2272 }
2273 *str = NULL;
2274 return ret;
2275}
2276EXPORT_SYMBOL_GPL(xdr_stream_decode_string_dup);