2 * linux/net/sunrpc/xdr.c
6 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
9 #include <linux/module.h>
10 #include <linux/slab.h>
11 #include <linux/types.h>
12 #include <linux/string.h>
13 #include <linux/kernel.h>
14 #include <linux/pagemap.h>
15 #include <linux/errno.h>
16 #include <linux/sunrpc/xdr.h>
17 #include <linux/sunrpc/msg_prot.h>
20 * XDR functions for basic NFS types
23 xdr_encode_netobj(__be32
*p
, const struct xdr_netobj
*obj
)
25 unsigned int quadlen
= XDR_QUADLEN(obj
->len
);
27 p
[quadlen
] = 0; /* zero trailing bytes */
28 *p
++ = cpu_to_be32(obj
->len
);
29 memcpy(p
, obj
->data
, obj
->len
);
30 return p
+ XDR_QUADLEN(obj
->len
);
32 EXPORT_SYMBOL_GPL(xdr_encode_netobj
);
35 xdr_decode_netobj(__be32
*p
, struct xdr_netobj
*obj
)
39 if ((len
= be32_to_cpu(*p
++)) > XDR_MAX_NETOBJ
)
43 return p
+ XDR_QUADLEN(len
);
45 EXPORT_SYMBOL_GPL(xdr_decode_netobj
);
48 * xdr_encode_opaque_fixed - Encode fixed length opaque data
49 * @p: pointer to current position in XDR buffer.
50 * @ptr: pointer to data to encode (or NULL)
51 * @nbytes: size of data.
53 * Copy the array of data of length nbytes at ptr to the XDR buffer
54 * at position p, then align to the next 32-bit boundary by padding
55 * with zero bytes (see RFC1832).
56 * Note: if ptr is NULL, only the padding is performed.
58 * Returns the updated current XDR buffer position
61 __be32
*xdr_encode_opaque_fixed(__be32
*p
, const void *ptr
, unsigned int nbytes
)
63 if (likely(nbytes
!= 0)) {
64 unsigned int quadlen
= XDR_QUADLEN(nbytes
);
65 unsigned int padding
= (quadlen
<< 2) - nbytes
;
68 memcpy(p
, ptr
, nbytes
);
70 memset((char *)p
+ nbytes
, 0, padding
);
75 EXPORT_SYMBOL_GPL(xdr_encode_opaque_fixed
);
78 * xdr_encode_opaque - Encode variable length opaque data
79 * @p: pointer to current position in XDR buffer.
80 * @ptr: pointer to data to encode (or NULL)
81 * @nbytes: size of data.
83 * Returns the updated current XDR buffer position
85 __be32
*xdr_encode_opaque(__be32
*p
, const void *ptr
, unsigned int nbytes
)
87 *p
++ = cpu_to_be32(nbytes
);
88 return xdr_encode_opaque_fixed(p
, ptr
, nbytes
);
90 EXPORT_SYMBOL_GPL(xdr_encode_opaque
);
93 xdr_encode_string(__be32
*p
, const char *string
)
95 return xdr_encode_array(p
, string
, strlen(string
));
97 EXPORT_SYMBOL_GPL(xdr_encode_string
);
100 xdr_decode_string_inplace(__be32
*p
, char **sp
,
101 unsigned int *lenp
, unsigned int maxlen
)
105 len
= be32_to_cpu(*p
++);
110 return p
+ XDR_QUADLEN(len
);
112 EXPORT_SYMBOL_GPL(xdr_decode_string_inplace
);
115 * xdr_terminate_string - '\0'-terminate a string residing in an xdr_buf
116 * @buf: XDR buffer where string resides
117 * @len: length of string, in bytes
121 xdr_terminate_string(struct xdr_buf
*buf
, const u32 len
)
125 kaddr
= kmap_atomic(buf
->pages
[0]);
126 kaddr
[buf
->page_base
+ len
] = '\0';
127 kunmap_atomic(kaddr
);
129 EXPORT_SYMBOL_GPL(xdr_terminate_string
);
132 xdr_inline_pages(struct xdr_buf
*xdr
, unsigned int offset
,
133 struct page
**pages
, unsigned int base
, unsigned int len
)
135 struct kvec
*head
= xdr
->head
;
136 struct kvec
*tail
= xdr
->tail
;
137 char *buf
= (char *)head
->iov_base
;
138 unsigned int buflen
= head
->iov_len
;
140 head
->iov_len
= offset
;
143 xdr
->page_base
= base
;
146 tail
->iov_base
= buf
+ offset
;
147 tail
->iov_len
= buflen
- offset
;
151 EXPORT_SYMBOL_GPL(xdr_inline_pages
);
154 * Helper routines for doing 'memmove' like operations on a struct xdr_buf
158 * _shift_data_right_pages
159 * @pages: vector of pages containing both the source and dest memory area.
160 * @pgto_base: page vector address of destination
161 * @pgfrom_base: page vector address of source
162 * @len: number of bytes to copy
164 * Note: the addresses pgto_base and pgfrom_base are both calculated in
166 * if a memory area starts at byte 'base' in page 'pages[i]',
167 * then its address is given as (i << PAGE_CACHE_SHIFT) + base
168 * Also note: pgfrom_base must be < pgto_base, but the memory areas
169 * they point to may overlap.
172 _shift_data_right_pages(struct page
**pages
, size_t pgto_base
,
173 size_t pgfrom_base
, size_t len
)
175 struct page
**pgfrom
, **pgto
;
179 BUG_ON(pgto_base
<= pgfrom_base
);
184 pgto
= pages
+ (pgto_base
>> PAGE_CACHE_SHIFT
);
185 pgfrom
= pages
+ (pgfrom_base
>> PAGE_CACHE_SHIFT
);
187 pgto_base
&= ~PAGE_CACHE_MASK
;
188 pgfrom_base
&= ~PAGE_CACHE_MASK
;
191 /* Are any pointers crossing a page boundary? */
192 if (pgto_base
== 0) {
193 pgto_base
= PAGE_CACHE_SIZE
;
196 if (pgfrom_base
== 0) {
197 pgfrom_base
= PAGE_CACHE_SIZE
;
202 if (copy
> pgto_base
)
204 if (copy
> pgfrom_base
)
209 vto
= kmap_atomic(*pgto
);
210 if (*pgto
!= *pgfrom
) {
211 vfrom
= kmap_atomic(*pgfrom
);
212 memcpy(vto
+ pgto_base
, vfrom
+ pgfrom_base
, copy
);
213 kunmap_atomic(vfrom
);
215 memmove(vto
+ pgto_base
, vto
+ pgfrom_base
, copy
);
216 flush_dcache_page(*pgto
);
219 } while ((len
-= copy
) != 0);
224 * @pages: array of pages
225 * @pgbase: page vector address of destination
226 * @p: pointer to source data
229 * Copies data from an arbitrary memory location into an array of pages
230 * The copy is assumed to be non-overlapping.
233 _copy_to_pages(struct page
**pages
, size_t pgbase
, const char *p
, size_t len
)
239 pgto
= pages
+ (pgbase
>> PAGE_CACHE_SHIFT
);
240 pgbase
&= ~PAGE_CACHE_MASK
;
243 copy
= PAGE_CACHE_SIZE
- pgbase
;
247 vto
= kmap_atomic(*pgto
);
248 memcpy(vto
+ pgbase
, p
, copy
);
256 if (pgbase
== PAGE_CACHE_SIZE
) {
257 flush_dcache_page(*pgto
);
263 flush_dcache_page(*pgto
);
268 * @p: pointer to destination
269 * @pages: array of pages
270 * @pgbase: offset of source data
273 * Copies data into an arbitrary memory location from an array of pages
274 * The copy is assumed to be non-overlapping.
277 _copy_from_pages(char *p
, struct page
**pages
, size_t pgbase
, size_t len
)
279 struct page
**pgfrom
;
283 pgfrom
= pages
+ (pgbase
>> PAGE_CACHE_SHIFT
);
284 pgbase
&= ~PAGE_CACHE_MASK
;
287 copy
= PAGE_CACHE_SIZE
- pgbase
;
291 vfrom
= kmap_atomic(*pgfrom
);
292 memcpy(p
, vfrom
+ pgbase
, copy
);
293 kunmap_atomic(vfrom
);
296 if (pgbase
== PAGE_CACHE_SIZE
) {
302 } while ((len
-= copy
) != 0);
304 EXPORT_SYMBOL_GPL(_copy_from_pages
);
309 * @len: bytes to remove from buf->head[0]
311 * Shrinks XDR buffer's header kvec buf->head[0] by
312 * 'len' bytes. The extra data is not lost, but is instead
313 * moved into the inlined pages and/or the tail.
316 xdr_shrink_bufhead(struct xdr_buf
*buf
, size_t len
)
318 struct kvec
*head
, *tail
;
320 unsigned int pglen
= buf
->page_len
;
325 WARN_ON_ONCE(len
> head
->iov_len
);
326 if (len
> head
->iov_len
)
329 /* Shift the tail first */
330 if (tail
->iov_len
!= 0) {
331 if (tail
->iov_len
> len
) {
332 copy
= tail
->iov_len
- len
;
333 memmove((char *)tail
->iov_base
+ len
,
334 tail
->iov_base
, copy
);
336 /* Copy from the inlined pages into the tail */
341 if (offs
>= tail
->iov_len
)
343 else if (copy
> tail
->iov_len
- offs
)
344 copy
= tail
->iov_len
- offs
;
346 _copy_from_pages((char *)tail
->iov_base
+ offs
,
348 buf
->page_base
+ pglen
+ offs
- len
,
350 /* Do we also need to copy data from the head into the tail ? */
352 offs
= copy
= len
- pglen
;
353 if (copy
> tail
->iov_len
)
354 copy
= tail
->iov_len
;
355 memcpy(tail
->iov_base
,
356 (char *)head
->iov_base
+
357 head
->iov_len
- offs
,
361 /* Now handle pages */
364 _shift_data_right_pages(buf
->pages
,
365 buf
->page_base
+ len
,
371 _copy_to_pages(buf
->pages
, buf
->page_base
,
372 (char *)head
->iov_base
+ head
->iov_len
- len
,
375 head
->iov_len
-= len
;
377 /* Have we truncated the message? */
378 if (buf
->len
> buf
->buflen
)
379 buf
->len
= buf
->buflen
;
385 * @len: bytes to remove from buf->pages
387 * Shrinks XDR buffer's page array buf->pages by
388 * 'len' bytes. The extra data is not lost, but is instead
389 * moved into the tail.
392 xdr_shrink_pagelen(struct xdr_buf
*buf
, size_t len
)
396 unsigned int pglen
= buf
->page_len
;
397 unsigned int tailbuf_len
;
400 BUG_ON (len
> pglen
);
402 tailbuf_len
= buf
->buflen
- buf
->head
->iov_len
- buf
->page_len
;
404 /* Shift the tail first */
405 if (tailbuf_len
!= 0) {
406 unsigned int free_space
= tailbuf_len
- tail
->iov_len
;
408 if (len
< free_space
)
410 tail
->iov_len
+= free_space
;
413 if (tail
->iov_len
> len
) {
414 char *p
= (char *)tail
->iov_base
+ len
;
415 memmove(p
, tail
->iov_base
, tail
->iov_len
- len
);
417 copy
= tail
->iov_len
;
418 /* Copy from the inlined pages into the tail */
419 _copy_from_pages((char *)tail
->iov_base
,
420 buf
->pages
, buf
->page_base
+ pglen
- len
,
423 buf
->page_len
-= len
;
425 /* Have we truncated the message? */
426 if (buf
->len
> buf
->buflen
)
427 buf
->len
= buf
->buflen
;
431 xdr_shift_buf(struct xdr_buf
*buf
, size_t len
)
433 xdr_shrink_bufhead(buf
, len
);
435 EXPORT_SYMBOL_GPL(xdr_shift_buf
);
438 * xdr_stream_pos - Return the current offset from the start of the xdr_stream
439 * @xdr: pointer to struct xdr_stream
441 unsigned int xdr_stream_pos(const struct xdr_stream
*xdr
)
443 return (unsigned int)(XDR_QUADLEN(xdr
->buf
->len
) - xdr
->nwords
) << 2;
445 EXPORT_SYMBOL_GPL(xdr_stream_pos
);
448 * xdr_init_encode - Initialize a struct xdr_stream for sending data.
449 * @xdr: pointer to xdr_stream struct
450 * @buf: pointer to XDR buffer in which to encode data
451 * @p: current pointer inside XDR buffer
453 * Note: at the moment the RPC client only passes the length of our
454 * scratch buffer in the xdr_buf's header kvec. Previously this
455 * meant we needed to call xdr_adjust_iovec() after encoding the
456 * data. With the new scheme, the xdr_stream manages the details
457 * of the buffer length, and takes care of adjusting the kvec
460 void xdr_init_encode(struct xdr_stream
*xdr
, struct xdr_buf
*buf
, __be32
*p
)
462 struct kvec
*iov
= buf
->head
;
463 int scratch_len
= buf
->buflen
- buf
->page_len
- buf
->tail
[0].iov_len
;
465 xdr_set_scratch_buffer(xdr
, NULL
, 0);
466 BUG_ON(scratch_len
< 0);
469 xdr
->p
= (__be32
*)((char *)iov
->iov_base
+ iov
->iov_len
);
470 xdr
->end
= (__be32
*)((char *)iov
->iov_base
+ scratch_len
);
471 BUG_ON(iov
->iov_len
> scratch_len
);
473 if (p
!= xdr
->p
&& p
!= NULL
) {
476 BUG_ON(p
< xdr
->p
|| p
> xdr
->end
);
477 len
= (char *)p
- (char *)xdr
->p
;
483 EXPORT_SYMBOL_GPL(xdr_init_encode
);
486 * xdr_commit_encode - Ensure all data is written to buffer
487 * @xdr: pointer to xdr_stream
489 * We handle encoding across page boundaries by giving the caller a
490 * temporary location to write to, then later copying the data into
491 * place; xdr_commit_encode does that copying.
493 * Normally the caller doesn't need to call this directly, as the
494 * following xdr_reserve_space will do it. But an explicit call may be
495 * required at the end of encoding, or any other time when the xdr_buf
496 * data might be read.
498 void xdr_commit_encode(struct xdr_stream
*xdr
)
500 int shift
= xdr
->scratch
.iov_len
;
505 page
= page_address(*xdr
->page_ptr
);
506 memcpy(xdr
->scratch
.iov_base
, page
, shift
);
507 memmove(page
, page
+ shift
, (void *)xdr
->p
- page
);
508 xdr
->scratch
.iov_len
= 0;
510 EXPORT_SYMBOL_GPL(xdr_commit_encode
);
512 __be32
*xdr_get_next_encode_buffer(struct xdr_stream
*xdr
, size_t nbytes
)
516 int frag1bytes
, frag2bytes
;
518 if (nbytes
> PAGE_SIZE
)
519 return NULL
; /* Bigger buffers require special handling */
520 if (xdr
->buf
->len
+ nbytes
> xdr
->buf
->buflen
)
521 return NULL
; /* Sorry, we're totally out of space */
522 frag1bytes
= (xdr
->end
- xdr
->p
) << 2;
523 frag2bytes
= nbytes
- frag1bytes
;
525 xdr
->iov
->iov_len
+= frag1bytes
;
527 xdr
->buf
->page_len
+= frag1bytes
;
531 * If the last encode didn't end exactly on a page boundary, the
532 * next one will straddle boundaries. Encode into the next
533 * page, then copy it back later in xdr_commit_encode. We use
534 * the "scratch" iov to track any temporarily unused fragment of
535 * space at the end of the previous buffer:
537 xdr
->scratch
.iov_base
= xdr
->p
;
538 xdr
->scratch
.iov_len
= frag1bytes
;
539 p
= page_address(*xdr
->page_ptr
);
541 * Note this is where the next encode will start after we've
542 * shifted this one back:
544 xdr
->p
= (void *)p
+ frag2bytes
;
545 space_left
= xdr
->buf
->buflen
- xdr
->buf
->len
;
546 xdr
->end
= (void *)p
+ min_t(int, space_left
, PAGE_SIZE
);
547 xdr
->buf
->page_len
+= frag2bytes
;
548 xdr
->buf
->len
+= nbytes
;
553 * xdr_reserve_space - Reserve buffer space for sending
554 * @xdr: pointer to xdr_stream
555 * @nbytes: number of bytes to reserve
557 * Checks that we have enough buffer space to encode 'nbytes' more
558 * bytes of data. If so, update the total xdr_buf length, and
559 * adjust the length of the current kvec.
561 __be32
* xdr_reserve_space(struct xdr_stream
*xdr
, size_t nbytes
)
566 xdr_commit_encode(xdr
);
567 /* align nbytes on the next 32-bit boundary */
570 q
= p
+ (nbytes
>> 2);
571 if (unlikely(q
> xdr
->end
|| q
< p
))
572 return xdr_get_next_encode_buffer(xdr
, nbytes
);
575 xdr
->iov
->iov_len
+= nbytes
;
577 xdr
->buf
->page_len
+= nbytes
;
578 xdr
->buf
->len
+= nbytes
;
581 EXPORT_SYMBOL_GPL(xdr_reserve_space
);
584 * xdr_truncate_encode - truncate an encode buffer
585 * @xdr: pointer to xdr_stream
586 * @len: new length of buffer
588 * Truncates the xdr stream, so that xdr->buf->len == len,
589 * and xdr->p points at offset len from the start of the buffer, and
590 * head, tail, and page lengths are adjusted to correspond.
592 * If this means moving xdr->p to a different buffer, we assume that
593 * that the end pointer should be set to the end of the current page,
594 * except in the case of the head buffer when we assume the head
595 * buffer's current length represents the end of the available buffer.
597 * This is *not* safe to use on a buffer that already has inlined page
598 * cache pages (as in a zero-copy server read reply), except for the
599 * simple case of truncating from one position in the tail to another.
602 void xdr_truncate_encode(struct xdr_stream
*xdr
, size_t len
)
604 struct xdr_buf
*buf
= xdr
->buf
;
605 struct kvec
*head
= buf
->head
;
606 struct kvec
*tail
= buf
->tail
;
610 if (len
> buf
->len
) {
614 xdr_commit_encode(xdr
);
616 fraglen
= min_t(int, buf
->len
- len
, tail
->iov_len
);
617 tail
->iov_len
-= fraglen
;
619 if (tail
->iov_len
&& buf
->len
== len
) {
620 xdr
->p
= tail
->iov_base
+ tail
->iov_len
;
621 /* xdr->end, xdr->iov should be set already */
624 WARN_ON_ONCE(fraglen
);
625 fraglen
= min_t(int, buf
->len
- len
, buf
->page_len
);
626 buf
->page_len
-= fraglen
;
629 new = buf
->page_base
+ buf
->page_len
;
631 xdr
->page_ptr
-= (old
>> PAGE_SHIFT
) - (new >> PAGE_SHIFT
);
633 if (buf
->page_len
&& buf
->len
== len
) {
634 xdr
->p
= page_address(*xdr
->page_ptr
);
635 xdr
->end
= (void *)xdr
->p
+ PAGE_SIZE
;
636 xdr
->p
= (void *)xdr
->p
+ (new % PAGE_SIZE
);
637 /* xdr->iov should already be NULL */
641 xdr
->end
= head
->iov_base
+ head
->iov_len
;
644 /* (otherwise assume xdr->end is already set) */
647 xdr
->p
= head
->iov_base
+ head
->iov_len
;
648 xdr
->iov
= buf
->head
;
650 EXPORT_SYMBOL(xdr_truncate_encode
);
653 * xdr_restrict_buflen - decrease available buffer space
654 * @xdr: pointer to xdr_stream
655 * @newbuflen: new maximum number of bytes available
657 * Adjust our idea of how much space is available in the buffer.
658 * If we've already used too much space in the buffer, returns -1.
659 * If the available space is already smaller than newbuflen, returns 0
660 * and does nothing. Otherwise, adjusts xdr->buf->buflen to newbuflen
661 * and ensures xdr->end is set at most offset newbuflen from the start
664 int xdr_restrict_buflen(struct xdr_stream
*xdr
, int newbuflen
)
666 struct xdr_buf
*buf
= xdr
->buf
;
667 int left_in_this_buf
= (void *)xdr
->end
- (void *)xdr
->p
;
668 int end_offset
= buf
->len
+ left_in_this_buf
;
670 if (newbuflen
< 0 || newbuflen
< buf
->len
)
672 if (newbuflen
> buf
->buflen
)
674 if (newbuflen
< end_offset
)
675 xdr
->end
= (void *)xdr
->end
+ newbuflen
- end_offset
;
676 buf
->buflen
= newbuflen
;
679 EXPORT_SYMBOL(xdr_restrict_buflen
);
682 * xdr_write_pages - Insert a list of pages into an XDR buffer for sending
683 * @xdr: pointer to xdr_stream
684 * @pages: list of pages
685 * @base: offset of first byte
686 * @len: length of data in bytes
689 void xdr_write_pages(struct xdr_stream
*xdr
, struct page
**pages
, unsigned int base
,
692 struct xdr_buf
*buf
= xdr
->buf
;
693 struct kvec
*iov
= buf
->tail
;
695 buf
->page_base
= base
;
698 iov
->iov_base
= (char *)xdr
->p
;
703 unsigned int pad
= 4 - (len
& 3);
705 BUG_ON(xdr
->p
>= xdr
->end
);
706 iov
->iov_base
= (char *)xdr
->p
+ (len
& 3);
714 EXPORT_SYMBOL_GPL(xdr_write_pages
);
716 static void xdr_set_iov(struct xdr_stream
*xdr
, struct kvec
*iov
,
719 if (len
> iov
->iov_len
)
721 xdr
->p
= (__be32
*)iov
->iov_base
;
722 xdr
->end
= (__be32
*)(iov
->iov_base
+ len
);
724 xdr
->page_ptr
= NULL
;
727 static int xdr_set_page_base(struct xdr_stream
*xdr
,
728 unsigned int base
, unsigned int len
)
736 maxlen
= xdr
->buf
->page_len
;
743 base
+= xdr
->buf
->page_base
;
745 pgnr
= base
>> PAGE_SHIFT
;
746 xdr
->page_ptr
= &xdr
->buf
->pages
[pgnr
];
747 kaddr
= page_address(*xdr
->page_ptr
);
749 pgoff
= base
& ~PAGE_MASK
;
750 xdr
->p
= (__be32
*)(kaddr
+ pgoff
);
753 if (pgend
> PAGE_SIZE
)
755 xdr
->end
= (__be32
*)(kaddr
+ pgend
);
760 static void xdr_set_next_page(struct xdr_stream
*xdr
)
762 unsigned int newbase
;
764 newbase
= (1 + xdr
->page_ptr
- xdr
->buf
->pages
) << PAGE_SHIFT
;
765 newbase
-= xdr
->buf
->page_base
;
767 if (xdr_set_page_base(xdr
, newbase
, PAGE_SIZE
) < 0)
768 xdr_set_iov(xdr
, xdr
->buf
->tail
, xdr
->buf
->len
);
771 static bool xdr_set_next_buffer(struct xdr_stream
*xdr
)
773 if (xdr
->page_ptr
!= NULL
)
774 xdr_set_next_page(xdr
);
775 else if (xdr
->iov
== xdr
->buf
->head
) {
776 if (xdr_set_page_base(xdr
, 0, PAGE_SIZE
) < 0)
777 xdr_set_iov(xdr
, xdr
->buf
->tail
, xdr
->buf
->len
);
779 return xdr
->p
!= xdr
->end
;
783 * xdr_init_decode - Initialize an xdr_stream for decoding data.
784 * @xdr: pointer to xdr_stream struct
785 * @buf: pointer to XDR buffer from which to decode data
786 * @p: current pointer inside XDR buffer
788 void xdr_init_decode(struct xdr_stream
*xdr
, struct xdr_buf
*buf
, __be32
*p
)
791 xdr
->scratch
.iov_base
= NULL
;
792 xdr
->scratch
.iov_len
= 0;
793 xdr
->nwords
= XDR_QUADLEN(buf
->len
);
794 if (buf
->head
[0].iov_len
!= 0)
795 xdr_set_iov(xdr
, buf
->head
, buf
->len
);
796 else if (buf
->page_len
!= 0)
797 xdr_set_page_base(xdr
, 0, buf
->len
);
798 if (p
!= NULL
&& p
> xdr
->p
&& xdr
->end
>= p
) {
799 xdr
->nwords
-= p
- xdr
->p
;
803 EXPORT_SYMBOL_GPL(xdr_init_decode
);
806 * xdr_init_decode - Initialize an xdr_stream for decoding data.
807 * @xdr: pointer to xdr_stream struct
808 * @buf: pointer to XDR buffer from which to decode data
809 * @pages: list of pages to decode into
810 * @len: length in bytes of buffer in pages
812 void xdr_init_decode_pages(struct xdr_stream
*xdr
, struct xdr_buf
*buf
,
813 struct page
**pages
, unsigned int len
)
815 memset(buf
, 0, sizeof(*buf
));
820 xdr_init_decode(xdr
, buf
, NULL
);
822 EXPORT_SYMBOL_GPL(xdr_init_decode_pages
);
824 static __be32
* __xdr_inline_decode(struct xdr_stream
*xdr
, size_t nbytes
)
826 unsigned int nwords
= XDR_QUADLEN(nbytes
);
828 __be32
*q
= p
+ nwords
;
830 if (unlikely(nwords
> xdr
->nwords
|| q
> xdr
->end
|| q
< p
))
833 xdr
->nwords
-= nwords
;
838 * xdr_set_scratch_buffer - Attach a scratch buffer for decoding data.
839 * @xdr: pointer to xdr_stream struct
840 * @buf: pointer to an empty buffer
841 * @buflen: size of 'buf'
843 * The scratch buffer is used when decoding from an array of pages.
844 * If an xdr_inline_decode() call spans across page boundaries, then
845 * we copy the data into the scratch buffer in order to allow linear
848 void xdr_set_scratch_buffer(struct xdr_stream
*xdr
, void *buf
, size_t buflen
)
850 xdr
->scratch
.iov_base
= buf
;
851 xdr
->scratch
.iov_len
= buflen
;
853 EXPORT_SYMBOL_GPL(xdr_set_scratch_buffer
);
855 static __be32
*xdr_copy_to_scratch(struct xdr_stream
*xdr
, size_t nbytes
)
858 void *cpdest
= xdr
->scratch
.iov_base
;
859 size_t cplen
= (char *)xdr
->end
- (char *)xdr
->p
;
861 if (nbytes
> xdr
->scratch
.iov_len
)
863 memcpy(cpdest
, xdr
->p
, cplen
);
866 if (!xdr_set_next_buffer(xdr
))
868 p
= __xdr_inline_decode(xdr
, nbytes
);
871 memcpy(cpdest
, p
, nbytes
);
872 return xdr
->scratch
.iov_base
;
876 * xdr_inline_decode - Retrieve XDR data to decode
877 * @xdr: pointer to xdr_stream struct
878 * @nbytes: number of bytes of data to decode
880 * Check if the input buffer is long enough to enable us to decode
881 * 'nbytes' more bytes of data starting at the current position.
882 * If so return the current pointer, then update the current
885 __be32
* xdr_inline_decode(struct xdr_stream
*xdr
, size_t nbytes
)
891 if (xdr
->p
== xdr
->end
&& !xdr_set_next_buffer(xdr
))
893 p
= __xdr_inline_decode(xdr
, nbytes
);
896 return xdr_copy_to_scratch(xdr
, nbytes
);
898 EXPORT_SYMBOL_GPL(xdr_inline_decode
);
900 static unsigned int xdr_align_pages(struct xdr_stream
*xdr
, unsigned int len
)
902 struct xdr_buf
*buf
= xdr
->buf
;
904 unsigned int nwords
= XDR_QUADLEN(len
);
905 unsigned int cur
= xdr_stream_pos(xdr
);
907 if (xdr
->nwords
== 0)
909 /* Realign pages to current pointer position */
911 if (iov
->iov_len
> cur
) {
912 xdr_shrink_bufhead(buf
, iov
->iov_len
- cur
);
913 xdr
->nwords
= XDR_QUADLEN(buf
->len
- cur
);
916 if (nwords
> xdr
->nwords
) {
917 nwords
= xdr
->nwords
;
920 if (buf
->page_len
<= len
)
922 else if (nwords
< xdr
->nwords
) {
923 /* Truncate page data and move it into the tail */
924 xdr_shrink_pagelen(buf
, buf
->page_len
- len
);
925 xdr
->nwords
= XDR_QUADLEN(buf
->len
- cur
);
931 * xdr_read_pages - Ensure page-based XDR data to decode is aligned at current pointer position
932 * @xdr: pointer to xdr_stream struct
933 * @len: number of bytes of page data
935 * Moves data beyond the current pointer position from the XDR head[] buffer
936 * into the page list. Any data that lies beyond current position + "len"
937 * bytes is moved into the XDR tail[].
939 * Returns the number of XDR encoded bytes now contained in the pages
941 unsigned int xdr_read_pages(struct xdr_stream
*xdr
, unsigned int len
)
943 struct xdr_buf
*buf
= xdr
->buf
;
947 unsigned int padding
;
949 len
= xdr_align_pages(xdr
, len
);
952 nwords
= XDR_QUADLEN(len
);
953 padding
= (nwords
<< 2) - len
;
954 xdr
->iov
= iov
= buf
->tail
;
955 /* Compute remaining message length. */
956 end
= ((xdr
->nwords
- nwords
) << 2) + padding
;
957 if (end
> iov
->iov_len
)
961 * Position current pointer at beginning of tail, and
962 * set remaining message length.
964 xdr
->p
= (__be32
*)((char *)iov
->iov_base
+ padding
);
965 xdr
->end
= (__be32
*)((char *)iov
->iov_base
+ end
);
966 xdr
->page_ptr
= NULL
;
967 xdr
->nwords
= XDR_QUADLEN(end
- padding
);
970 EXPORT_SYMBOL_GPL(xdr_read_pages
);
973 * xdr_enter_page - decode data from the XDR page
974 * @xdr: pointer to xdr_stream struct
975 * @len: number of bytes of page data
977 * Moves data beyond the current pointer position from the XDR head[] buffer
978 * into the page list. Any data that lies beyond current position + "len"
979 * bytes is moved into the XDR tail[]. The current pointer is then
980 * repositioned at the beginning of the first XDR page.
982 void xdr_enter_page(struct xdr_stream
*xdr
, unsigned int len
)
984 len
= xdr_align_pages(xdr
, len
);
986 * Position current pointer at beginning of tail, and
987 * set remaining message length.
990 xdr_set_page_base(xdr
, 0, len
);
992 EXPORT_SYMBOL_GPL(xdr_enter_page
);
994 static struct kvec empty_iov
= {.iov_base
= NULL
, .iov_len
= 0};
997 xdr_buf_from_iov(struct kvec
*iov
, struct xdr_buf
*buf
)
1000 buf
->tail
[0] = empty_iov
;
1002 buf
->buflen
= buf
->len
= iov
->iov_len
;
1004 EXPORT_SYMBOL_GPL(xdr_buf_from_iov
);
1007 * xdr_buf_subsegment - set subbuf to a portion of buf
1008 * @buf: an xdr buffer
1009 * @subbuf: the result buffer
1010 * @base: beginning of range in bytes
1011 * @len: length of range in bytes
1013 * sets @subbuf to an xdr buffer representing the portion of @buf of
1014 * length @len starting at offset @base.
1016 * @buf and @subbuf may be pointers to the same struct xdr_buf.
1018 * Returns -1 if base of length are out of bounds.
1021 xdr_buf_subsegment(struct xdr_buf
*buf
, struct xdr_buf
*subbuf
,
1022 unsigned int base
, unsigned int len
)
1024 subbuf
->buflen
= subbuf
->len
= len
;
1025 if (base
< buf
->head
[0].iov_len
) {
1026 subbuf
->head
[0].iov_base
= buf
->head
[0].iov_base
+ base
;
1027 subbuf
->head
[0].iov_len
= min_t(unsigned int, len
,
1028 buf
->head
[0].iov_len
- base
);
1029 len
-= subbuf
->head
[0].iov_len
;
1032 base
-= buf
->head
[0].iov_len
;
1033 subbuf
->head
[0].iov_len
= 0;
1036 if (base
< buf
->page_len
) {
1037 subbuf
->page_len
= min(buf
->page_len
- base
, len
);
1038 base
+= buf
->page_base
;
1039 subbuf
->page_base
= base
& ~PAGE_CACHE_MASK
;
1040 subbuf
->pages
= &buf
->pages
[base
>> PAGE_CACHE_SHIFT
];
1041 len
-= subbuf
->page_len
;
1044 base
-= buf
->page_len
;
1045 subbuf
->page_len
= 0;
1048 if (base
< buf
->tail
[0].iov_len
) {
1049 subbuf
->tail
[0].iov_base
= buf
->tail
[0].iov_base
+ base
;
1050 subbuf
->tail
[0].iov_len
= min_t(unsigned int, len
,
1051 buf
->tail
[0].iov_len
- base
);
1052 len
-= subbuf
->tail
[0].iov_len
;
1055 base
-= buf
->tail
[0].iov_len
;
1056 subbuf
->tail
[0].iov_len
= 0;
1063 EXPORT_SYMBOL_GPL(xdr_buf_subsegment
);
1066 * xdr_buf_trim - lop at most "len" bytes off the end of "buf"
1067 * @buf: buf to be trimmed
1068 * @len: number of bytes to reduce "buf" by
1070 * Trim an xdr_buf by the given number of bytes by fixing up the lengths. Note
1071 * that it's possible that we'll trim less than that amount if the xdr_buf is
1072 * too small, or if (for instance) it's all in the head and the parser has
1073 * already read too far into it.
1075 void xdr_buf_trim(struct xdr_buf
*buf
, unsigned int len
)
1078 unsigned int trim
= len
;
1080 if (buf
->tail
[0].iov_len
) {
1081 cur
= min_t(size_t, buf
->tail
[0].iov_len
, trim
);
1082 buf
->tail
[0].iov_len
-= cur
;
1088 if (buf
->page_len
) {
1089 cur
= min_t(unsigned int, buf
->page_len
, trim
);
1090 buf
->page_len
-= cur
;
1096 if (buf
->head
[0].iov_len
) {
1097 cur
= min_t(size_t, buf
->head
[0].iov_len
, trim
);
1098 buf
->head
[0].iov_len
-= cur
;
1102 buf
->len
-= (len
- trim
);
1104 EXPORT_SYMBOL_GPL(xdr_buf_trim
);
1106 static void __read_bytes_from_xdr_buf(struct xdr_buf
*subbuf
, void *obj
, unsigned int len
)
1108 unsigned int this_len
;
1110 this_len
= min_t(unsigned int, len
, subbuf
->head
[0].iov_len
);
1111 memcpy(obj
, subbuf
->head
[0].iov_base
, this_len
);
1114 this_len
= min_t(unsigned int, len
, subbuf
->page_len
);
1116 _copy_from_pages(obj
, subbuf
->pages
, subbuf
->page_base
, this_len
);
1119 this_len
= min_t(unsigned int, len
, subbuf
->tail
[0].iov_len
);
1120 memcpy(obj
, subbuf
->tail
[0].iov_base
, this_len
);
1123 /* obj is assumed to point to allocated memory of size at least len: */
1124 int read_bytes_from_xdr_buf(struct xdr_buf
*buf
, unsigned int base
, void *obj
, unsigned int len
)
1126 struct xdr_buf subbuf
;
1129 status
= xdr_buf_subsegment(buf
, &subbuf
, base
, len
);
1132 __read_bytes_from_xdr_buf(&subbuf
, obj
, len
);
1135 EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf
);
1137 static void __write_bytes_to_xdr_buf(struct xdr_buf
*subbuf
, void *obj
, unsigned int len
)
1139 unsigned int this_len
;
1141 this_len
= min_t(unsigned int, len
, subbuf
->head
[0].iov_len
);
1142 memcpy(subbuf
->head
[0].iov_base
, obj
, this_len
);
1145 this_len
= min_t(unsigned int, len
, subbuf
->page_len
);
1147 _copy_to_pages(subbuf
->pages
, subbuf
->page_base
, obj
, this_len
);
1150 this_len
= min_t(unsigned int, len
, subbuf
->tail
[0].iov_len
);
1151 memcpy(subbuf
->tail
[0].iov_base
, obj
, this_len
);
1154 /* obj is assumed to point to allocated memory of size at least len: */
1155 int write_bytes_to_xdr_buf(struct xdr_buf
*buf
, unsigned int base
, void *obj
, unsigned int len
)
1157 struct xdr_buf subbuf
;
1160 status
= xdr_buf_subsegment(buf
, &subbuf
, base
, len
);
1163 __write_bytes_to_xdr_buf(&subbuf
, obj
, len
);
1166 EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf
);
1169 xdr_decode_word(struct xdr_buf
*buf
, unsigned int base
, u32
*obj
)
1174 status
= read_bytes_from_xdr_buf(buf
, base
, &raw
, sizeof(*obj
));
1177 *obj
= be32_to_cpu(raw
);
1180 EXPORT_SYMBOL_GPL(xdr_decode_word
);
1183 xdr_encode_word(struct xdr_buf
*buf
, unsigned int base
, u32 obj
)
1185 __be32 raw
= cpu_to_be32(obj
);
1187 return write_bytes_to_xdr_buf(buf
, base
, &raw
, sizeof(obj
));
1189 EXPORT_SYMBOL_GPL(xdr_encode_word
);
1191 /* If the netobj starting offset bytes from the start of xdr_buf is contained
1192 * entirely in the head or the tail, set object to point to it; otherwise
1193 * try to find space for it at the end of the tail, copy it there, and
1194 * set obj to point to it. */
1195 int xdr_buf_read_netobj(struct xdr_buf
*buf
, struct xdr_netobj
*obj
, unsigned int offset
)
1197 struct xdr_buf subbuf
;
1199 if (xdr_decode_word(buf
, offset
, &obj
->len
))
1201 if (xdr_buf_subsegment(buf
, &subbuf
, offset
+ 4, obj
->len
))
1204 /* Is the obj contained entirely in the head? */
1205 obj
->data
= subbuf
.head
[0].iov_base
;
1206 if (subbuf
.head
[0].iov_len
== obj
->len
)
1208 /* ..or is the obj contained entirely in the tail? */
1209 obj
->data
= subbuf
.tail
[0].iov_base
;
1210 if (subbuf
.tail
[0].iov_len
== obj
->len
)
1213 /* use end of tail as storage for obj:
1214 * (We don't copy to the beginning because then we'd have
1215 * to worry about doing a potentially overlapping copy.
1216 * This assumes the object is at most half the length of the
1218 if (obj
->len
> buf
->buflen
- buf
->len
)
1220 if (buf
->tail
[0].iov_len
!= 0)
1221 obj
->data
= buf
->tail
[0].iov_base
+ buf
->tail
[0].iov_len
;
1223 obj
->data
= buf
->head
[0].iov_base
+ buf
->head
[0].iov_len
;
1224 __read_bytes_from_xdr_buf(&subbuf
, obj
->data
, obj
->len
);
1227 EXPORT_SYMBOL_GPL(xdr_buf_read_netobj
);
1229 /* Returns 0 on success, or else a negative error code. */
1231 xdr_xcode_array2(struct xdr_buf
*buf
, unsigned int base
,
1232 struct xdr_array2_desc
*desc
, int encode
)
1234 char *elem
= NULL
, *c
;
1235 unsigned int copied
= 0, todo
, avail_here
;
1236 struct page
**ppages
= NULL
;
1240 if (xdr_encode_word(buf
, base
, desc
->array_len
) != 0)
1243 if (xdr_decode_word(buf
, base
, &desc
->array_len
) != 0 ||
1244 desc
->array_len
> desc
->array_maxlen
||
1245 (unsigned long) base
+ 4 + desc
->array_len
*
1246 desc
->elem_size
> buf
->len
)
1254 todo
= desc
->array_len
* desc
->elem_size
;
1257 if (todo
&& base
< buf
->head
->iov_len
) {
1258 c
= buf
->head
->iov_base
+ base
;
1259 avail_here
= min_t(unsigned int, todo
,
1260 buf
->head
->iov_len
- base
);
1263 while (avail_here
>= desc
->elem_size
) {
1264 err
= desc
->xcode(desc
, c
);
1267 c
+= desc
->elem_size
;
1268 avail_here
-= desc
->elem_size
;
1272 elem
= kmalloc(desc
->elem_size
, GFP_KERNEL
);
1278 err
= desc
->xcode(desc
, elem
);
1281 memcpy(c
, elem
, avail_here
);
1283 memcpy(elem
, c
, avail_here
);
1284 copied
= avail_here
;
1286 base
= buf
->head
->iov_len
; /* align to start of pages */
1289 /* process pages array */
1290 base
-= buf
->head
->iov_len
;
1291 if (todo
&& base
< buf
->page_len
) {
1292 unsigned int avail_page
;
1294 avail_here
= min(todo
, buf
->page_len
- base
);
1297 base
+= buf
->page_base
;
1298 ppages
= buf
->pages
+ (base
>> PAGE_CACHE_SHIFT
);
1299 base
&= ~PAGE_CACHE_MASK
;
1300 avail_page
= min_t(unsigned int, PAGE_CACHE_SIZE
- base
,
1302 c
= kmap(*ppages
) + base
;
1304 while (avail_here
) {
1305 avail_here
-= avail_page
;
1306 if (copied
|| avail_page
< desc
->elem_size
) {
1307 unsigned int l
= min(avail_page
,
1308 desc
->elem_size
- copied
);
1310 elem
= kmalloc(desc
->elem_size
,
1318 err
= desc
->xcode(desc
, elem
);
1322 memcpy(c
, elem
+ copied
, l
);
1324 if (copied
== desc
->elem_size
)
1327 memcpy(elem
+ copied
, c
, l
);
1329 if (copied
== desc
->elem_size
) {
1330 err
= desc
->xcode(desc
, elem
);
1339 while (avail_page
>= desc
->elem_size
) {
1340 err
= desc
->xcode(desc
, c
);
1343 c
+= desc
->elem_size
;
1344 avail_page
-= desc
->elem_size
;
1347 unsigned int l
= min(avail_page
,
1348 desc
->elem_size
- copied
);
1350 elem
= kmalloc(desc
->elem_size
,
1358 err
= desc
->xcode(desc
, elem
);
1362 memcpy(c
, elem
+ copied
, l
);
1364 if (copied
== desc
->elem_size
)
1367 memcpy(elem
+ copied
, c
, l
);
1369 if (copied
== desc
->elem_size
) {
1370 err
= desc
->xcode(desc
, elem
);
1383 avail_page
= min(avail_here
,
1384 (unsigned int) PAGE_CACHE_SIZE
);
1386 base
= buf
->page_len
; /* align to start of tail */
1390 base
-= buf
->page_len
;
1392 c
= buf
->tail
->iov_base
+ base
;
1394 unsigned int l
= desc
->elem_size
- copied
;
1397 memcpy(c
, elem
+ copied
, l
);
1399 memcpy(elem
+ copied
, c
, l
);
1400 err
= desc
->xcode(desc
, elem
);
1408 err
= desc
->xcode(desc
, c
);
1411 c
+= desc
->elem_size
;
1412 todo
-= desc
->elem_size
;
1425 xdr_decode_array2(struct xdr_buf
*buf
, unsigned int base
,
1426 struct xdr_array2_desc
*desc
)
1428 if (base
>= buf
->len
)
1431 return xdr_xcode_array2(buf
, base
, desc
, 0);
1433 EXPORT_SYMBOL_GPL(xdr_decode_array2
);
1436 xdr_encode_array2(struct xdr_buf
*buf
, unsigned int base
,
1437 struct xdr_array2_desc
*desc
)
1439 if ((unsigned long) base
+ 4 + desc
->array_len
* desc
->elem_size
>
1440 buf
->head
->iov_len
+ buf
->page_len
+ buf
->tail
->iov_len
)
1443 return xdr_xcode_array2(buf
, base
, desc
, 1);
1445 EXPORT_SYMBOL_GPL(xdr_encode_array2
);
1448 xdr_process_buf(struct xdr_buf
*buf
, unsigned int offset
, unsigned int len
,
1449 int (*actor
)(struct scatterlist
*, void *), void *data
)
1452 unsigned int page_len
, thislen
, page_offset
;
1453 struct scatterlist sg
[1];
1455 sg_init_table(sg
, 1);
1457 if (offset
>= buf
->head
[0].iov_len
) {
1458 offset
-= buf
->head
[0].iov_len
;
1460 thislen
= buf
->head
[0].iov_len
- offset
;
1463 sg_set_buf(sg
, buf
->head
[0].iov_base
+ offset
, thislen
);
1464 ret
= actor(sg
, data
);
1473 if (offset
>= buf
->page_len
) {
1474 offset
-= buf
->page_len
;
1476 page_len
= buf
->page_len
- offset
;
1480 page_offset
= (offset
+ buf
->page_base
) & (PAGE_CACHE_SIZE
- 1);
1481 i
= (offset
+ buf
->page_base
) >> PAGE_CACHE_SHIFT
;
1482 thislen
= PAGE_CACHE_SIZE
- page_offset
;
1484 if (thislen
> page_len
)
1486 sg_set_page(sg
, buf
->pages
[i
], thislen
, page_offset
);
1487 ret
= actor(sg
, data
);
1490 page_len
-= thislen
;
1493 thislen
= PAGE_CACHE_SIZE
;
1494 } while (page_len
!= 0);
1499 if (offset
< buf
->tail
[0].iov_len
) {
1500 thislen
= buf
->tail
[0].iov_len
- offset
;
1503 sg_set_buf(sg
, buf
->tail
[0].iov_base
+ offset
, thislen
);
1504 ret
= actor(sg
, data
);
1512 EXPORT_SYMBOL_GPL(xdr_process_buf
);