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