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_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_SHIFT);
185 pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);
187 pgto_base &= ~PAGE_MASK;
188 pgfrom_base &= ~PAGE_MASK;
191 /* Are any pointers crossing a page boundary? */
192 if (pgto_base == 0) {
193 pgto_base = PAGE_SIZE;
196 if (pgfrom_base == 0) {
197 pgfrom_base = PAGE_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_SHIFT);
240 pgbase &= ~PAGE_MASK;
243 copy = PAGE_SIZE - pgbase;
247 vto = kmap_atomic(*pgto);
248 memcpy(vto + pgbase, p, copy);
256 if (pgbase == PAGE_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_SHIFT);
284 pgbase &= ~PAGE_MASK;
287 copy = PAGE_SIZE - pgbase;
291 vfrom = kmap_atomic(*pgfrom);
292 memcpy(p, vfrom + pgbase, copy);
293 kunmap_atomic(vfrom);
296 if (pgbase == PAGE_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 static __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr,
517 int frag1bytes, frag2bytes;
519 if (nbytes > PAGE_SIZE)
520 return NULL; /* Bigger buffers require special handling */
521 if (xdr->buf->len + nbytes > xdr->buf->buflen)
522 return NULL; /* Sorry, we're totally out of space */
523 frag1bytes = (xdr->end - xdr->p) << 2;
524 frag2bytes = nbytes - frag1bytes;
526 xdr->iov->iov_len += frag1bytes;
528 xdr->buf->page_len += frag1bytes;
532 * If the last encode didn't end exactly on a page boundary, the
533 * next one will straddle boundaries. Encode into the next
534 * page, then copy it back later in xdr_commit_encode. We use
535 * the "scratch" iov to track any temporarily unused fragment of
536 * space at the end of the previous buffer:
538 xdr->scratch.iov_base = xdr->p;
539 xdr->scratch.iov_len = frag1bytes;
540 p = page_address(*xdr->page_ptr);
542 * Note this is where the next encode will start after we've
543 * shifted this one back:
545 xdr->p = (void *)p + frag2bytes;
546 space_left = xdr->buf->buflen - xdr->buf->len;
547 if (space_left - frag1bytes >= PAGE_SIZE)
548 xdr->end = (void *)p + PAGE_SIZE;
550 xdr->end = (void *)p + space_left - frag1bytes;
552 xdr->buf->page_len += frag2bytes;
553 xdr->buf->len += nbytes;
558 * xdr_reserve_space - Reserve buffer space for sending
559 * @xdr: pointer to xdr_stream
560 * @nbytes: number of bytes to reserve
562 * Checks that we have enough buffer space to encode 'nbytes' more
563 * bytes of data. If so, update the total xdr_buf length, and
564 * adjust the length of the current kvec.
566 __be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
571 xdr_commit_encode(xdr);
572 /* align nbytes on the next 32-bit boundary */
575 q = p + (nbytes >> 2);
576 if (unlikely(q > xdr->end || q < p))
577 return xdr_get_next_encode_buffer(xdr, nbytes);
580 xdr->iov->iov_len += nbytes;
582 xdr->buf->page_len += nbytes;
583 xdr->buf->len += nbytes;
586 EXPORT_SYMBOL_GPL(xdr_reserve_space);
589 * xdr_truncate_encode - truncate an encode buffer
590 * @xdr: pointer to xdr_stream
591 * @len: new length of buffer
593 * Truncates the xdr stream, so that xdr->buf->len == len,
594 * and xdr->p points at offset len from the start of the buffer, and
595 * head, tail, and page lengths are adjusted to correspond.
597 * If this means moving xdr->p to a different buffer, we assume that
598 * that the end pointer should be set to the end of the current page,
599 * except in the case of the head buffer when we assume the head
600 * buffer's current length represents the end of the available buffer.
602 * This is *not* safe to use on a buffer that already has inlined page
603 * cache pages (as in a zero-copy server read reply), except for the
604 * simple case of truncating from one position in the tail to another.
607 void xdr_truncate_encode(struct xdr_stream *xdr, size_t len)
609 struct xdr_buf *buf = xdr->buf;
610 struct kvec *head = buf->head;
611 struct kvec *tail = buf->tail;
615 if (len > buf->len) {
619 xdr_commit_encode(xdr);
621 fraglen = min_t(int, buf->len - len, tail->iov_len);
622 tail->iov_len -= fraglen;
625 xdr->p = tail->iov_base + tail->iov_len;
626 WARN_ON_ONCE(!xdr->end);
627 WARN_ON_ONCE(!xdr->iov);
630 WARN_ON_ONCE(fraglen);
631 fraglen = min_t(int, buf->len - len, buf->page_len);
632 buf->page_len -= fraglen;
635 new = buf->page_base + buf->page_len;
637 xdr->page_ptr = buf->pages + (new >> PAGE_SHIFT);
640 xdr->p = page_address(*xdr->page_ptr);
641 xdr->end = (void *)xdr->p + PAGE_SIZE;
642 xdr->p = (void *)xdr->p + (new % PAGE_SIZE);
643 WARN_ON_ONCE(xdr->iov);
647 xdr->end = head->iov_base + head->iov_len;
648 /* (otherwise assume xdr->end is already set) */
652 xdr->p = head->iov_base + head->iov_len;
653 xdr->iov = buf->head;
655 EXPORT_SYMBOL(xdr_truncate_encode);
658 * xdr_restrict_buflen - decrease available buffer space
659 * @xdr: pointer to xdr_stream
660 * @newbuflen: new maximum number of bytes available
662 * Adjust our idea of how much space is available in the buffer.
663 * If we've already used too much space in the buffer, returns -1.
664 * If the available space is already smaller than newbuflen, returns 0
665 * and does nothing. Otherwise, adjusts xdr->buf->buflen to newbuflen
666 * and ensures xdr->end is set at most offset newbuflen from the start
669 int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen)
671 struct xdr_buf *buf = xdr->buf;
672 int left_in_this_buf = (void *)xdr->end - (void *)xdr->p;
673 int end_offset = buf->len + left_in_this_buf;
675 if (newbuflen < 0 || newbuflen < buf->len)
677 if (newbuflen > buf->buflen)
679 if (newbuflen < end_offset)
680 xdr->end = (void *)xdr->end + newbuflen - end_offset;
681 buf->buflen = newbuflen;
684 EXPORT_SYMBOL(xdr_restrict_buflen);
687 * xdr_write_pages - Insert a list of pages into an XDR buffer for sending
688 * @xdr: pointer to xdr_stream
689 * @pages: list of pages
690 * @base: offset of first byte
691 * @len: length of data in bytes
694 void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base,
697 struct xdr_buf *buf = xdr->buf;
698 struct kvec *iov = buf->tail;
700 buf->page_base = base;
703 iov->iov_base = (char *)xdr->p;
708 unsigned int pad = 4 - (len & 3);
710 BUG_ON(xdr->p >= xdr->end);
711 iov->iov_base = (char *)xdr->p + (len & 3);
719 EXPORT_SYMBOL_GPL(xdr_write_pages);
721 static void xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
724 if (len > iov->iov_len)
726 xdr->p = (__be32*)iov->iov_base;
727 xdr->end = (__be32*)(iov->iov_base + len);
729 xdr->page_ptr = NULL;
732 static int xdr_set_page_base(struct xdr_stream *xdr,
733 unsigned int base, unsigned int len)
741 maxlen = xdr->buf->page_len;
748 base += xdr->buf->page_base;
750 pgnr = base >> PAGE_SHIFT;
751 xdr->page_ptr = &xdr->buf->pages[pgnr];
752 kaddr = page_address(*xdr->page_ptr);
754 pgoff = base & ~PAGE_MASK;
755 xdr->p = (__be32*)(kaddr + pgoff);
758 if (pgend > PAGE_SIZE)
760 xdr->end = (__be32*)(kaddr + pgend);
765 static void xdr_set_next_page(struct xdr_stream *xdr)
767 unsigned int newbase;
769 newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT;
770 newbase -= xdr->buf->page_base;
772 if (xdr_set_page_base(xdr, newbase, PAGE_SIZE) < 0)
773 xdr_set_iov(xdr, xdr->buf->tail, xdr->nwords << 2);
776 static bool xdr_set_next_buffer(struct xdr_stream *xdr)
778 if (xdr->page_ptr != NULL)
779 xdr_set_next_page(xdr);
780 else if (xdr->iov == xdr->buf->head) {
781 if (xdr_set_page_base(xdr, 0, PAGE_SIZE) < 0)
782 xdr_set_iov(xdr, xdr->buf->tail, xdr->nwords << 2);
784 return xdr->p != xdr->end;
788 * xdr_init_decode - Initialize an xdr_stream for decoding data.
789 * @xdr: pointer to xdr_stream struct
790 * @buf: pointer to XDR buffer from which to decode data
791 * @p: current pointer inside XDR buffer
793 void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
796 xdr->scratch.iov_base = NULL;
797 xdr->scratch.iov_len = 0;
798 xdr->nwords = XDR_QUADLEN(buf->len);
799 if (buf->head[0].iov_len != 0)
800 xdr_set_iov(xdr, buf->head, buf->len);
801 else if (buf->page_len != 0)
802 xdr_set_page_base(xdr, 0, buf->len);
804 xdr_set_iov(xdr, buf->head, buf->len);
805 if (p != NULL && p > xdr->p && xdr->end >= p) {
806 xdr->nwords -= p - xdr->p;
810 EXPORT_SYMBOL_GPL(xdr_init_decode);
813 * xdr_init_decode - Initialize an xdr_stream for decoding data.
814 * @xdr: pointer to xdr_stream struct
815 * @buf: pointer to XDR buffer from which to decode data
816 * @pages: list of pages to decode into
817 * @len: length in bytes of buffer in pages
819 void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
820 struct page **pages, unsigned int len)
822 memset(buf, 0, sizeof(*buf));
827 xdr_init_decode(xdr, buf, NULL);
829 EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
831 static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
833 unsigned int nwords = XDR_QUADLEN(nbytes);
835 __be32 *q = p + nwords;
837 if (unlikely(nwords > xdr->nwords || q > xdr->end || q < p))
840 xdr->nwords -= nwords;
845 * xdr_set_scratch_buffer - Attach a scratch buffer for decoding data.
846 * @xdr: pointer to xdr_stream struct
847 * @buf: pointer to an empty buffer
848 * @buflen: size of 'buf'
850 * The scratch buffer is used when decoding from an array of pages.
851 * If an xdr_inline_decode() call spans across page boundaries, then
852 * we copy the data into the scratch buffer in order to allow linear
855 void xdr_set_scratch_buffer(struct xdr_stream *xdr, void *buf, size_t buflen)
857 xdr->scratch.iov_base = buf;
858 xdr->scratch.iov_len = buflen;
860 EXPORT_SYMBOL_GPL(xdr_set_scratch_buffer);
862 static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes)
865 char *cpdest = xdr->scratch.iov_base;
866 size_t cplen = (char *)xdr->end - (char *)xdr->p;
868 if (nbytes > xdr->scratch.iov_len)
870 p = __xdr_inline_decode(xdr, cplen);
873 memcpy(cpdest, p, cplen);
876 if (!xdr_set_next_buffer(xdr))
878 p = __xdr_inline_decode(xdr, nbytes);
881 memcpy(cpdest, p, nbytes);
882 return xdr->scratch.iov_base;
886 * xdr_inline_decode - Retrieve XDR data to decode
887 * @xdr: pointer to xdr_stream struct
888 * @nbytes: number of bytes of data to decode
890 * Check if the input buffer is long enough to enable us to decode
891 * 'nbytes' more bytes of data starting at the current position.
892 * If so return the current pointer, then update the current
895 __be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
901 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
903 p = __xdr_inline_decode(xdr, nbytes);
906 return xdr_copy_to_scratch(xdr, nbytes);
908 EXPORT_SYMBOL_GPL(xdr_inline_decode);
910 static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len)
912 struct xdr_buf *buf = xdr->buf;
914 unsigned int nwords = XDR_QUADLEN(len);
915 unsigned int cur = xdr_stream_pos(xdr);
917 if (xdr->nwords == 0)
919 /* Realign pages to current pointer position */
921 if (iov->iov_len > cur) {
922 xdr_shrink_bufhead(buf, iov->iov_len - cur);
923 xdr->nwords = XDR_QUADLEN(buf->len - cur);
926 if (nwords > xdr->nwords) {
927 nwords = xdr->nwords;
930 if (buf->page_len <= len)
932 else if (nwords < xdr->nwords) {
933 /* Truncate page data and move it into the tail */
934 xdr_shrink_pagelen(buf, buf->page_len - len);
935 xdr->nwords = XDR_QUADLEN(buf->len - cur);
941 * xdr_read_pages - Ensure page-based XDR data to decode is aligned at current pointer position
942 * @xdr: pointer to xdr_stream struct
943 * @len: number of bytes of page data
945 * Moves data beyond the current pointer position from the XDR head[] buffer
946 * into the page list. Any data that lies beyond current position + "len"
947 * bytes is moved into the XDR tail[].
949 * Returns the number of XDR encoded bytes now contained in the pages
951 unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
953 struct xdr_buf *buf = xdr->buf;
957 unsigned int padding;
959 len = xdr_align_pages(xdr, len);
962 nwords = XDR_QUADLEN(len);
963 padding = (nwords << 2) - len;
964 xdr->iov = iov = buf->tail;
965 /* Compute remaining message length. */
966 end = ((xdr->nwords - nwords) << 2) + padding;
967 if (end > iov->iov_len)
971 * Position current pointer at beginning of tail, and
972 * set remaining message length.
974 xdr->p = (__be32 *)((char *)iov->iov_base + padding);
975 xdr->end = (__be32 *)((char *)iov->iov_base + end);
976 xdr->page_ptr = NULL;
977 xdr->nwords = XDR_QUADLEN(end - padding);
980 EXPORT_SYMBOL_GPL(xdr_read_pages);
983 * xdr_enter_page - decode data from the XDR page
984 * @xdr: pointer to xdr_stream struct
985 * @len: number of bytes of page data
987 * Moves data beyond the current pointer position from the XDR head[] buffer
988 * into the page list. Any data that lies beyond current position + "len"
989 * bytes is moved into the XDR tail[]. The current pointer is then
990 * repositioned at the beginning of the first XDR page.
992 void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
994 len = xdr_align_pages(xdr, len);
996 * Position current pointer at beginning of tail, and
997 * set remaining message length.
1000 xdr_set_page_base(xdr, 0, len);
1002 EXPORT_SYMBOL_GPL(xdr_enter_page);
1004 static struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0};
1007 xdr_buf_from_iov(struct kvec *iov, struct xdr_buf *buf)
1009 buf->head[0] = *iov;
1010 buf->tail[0] = empty_iov;
1012 buf->buflen = buf->len = iov->iov_len;
1014 EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
1017 * xdr_buf_subsegment - set subbuf to a portion of buf
1018 * @buf: an xdr buffer
1019 * @subbuf: the result buffer
1020 * @base: beginning of range in bytes
1021 * @len: length of range in bytes
1023 * sets @subbuf to an xdr buffer representing the portion of @buf of
1024 * length @len starting at offset @base.
1026 * @buf and @subbuf may be pointers to the same struct xdr_buf.
1028 * Returns -1 if base of length are out of bounds.
1031 xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
1032 unsigned int base, unsigned int len)
1034 subbuf->buflen = subbuf->len = len;
1035 if (base < buf->head[0].iov_len) {
1036 subbuf->head[0].iov_base = buf->head[0].iov_base + base;
1037 subbuf->head[0].iov_len = min_t(unsigned int, len,
1038 buf->head[0].iov_len - base);
1039 len -= subbuf->head[0].iov_len;
1042 base -= buf->head[0].iov_len;
1043 subbuf->head[0].iov_base = buf->head[0].iov_base;
1044 subbuf->head[0].iov_len = 0;
1047 if (base < buf->page_len) {
1048 subbuf->page_len = min(buf->page_len - base, len);
1049 base += buf->page_base;
1050 subbuf->page_base = base & ~PAGE_MASK;
1051 subbuf->pages = &buf->pages[base >> PAGE_SHIFT];
1052 len -= subbuf->page_len;
1055 base -= buf->page_len;
1056 subbuf->pages = buf->pages;
1057 subbuf->page_base = 0;
1058 subbuf->page_len = 0;
1061 if (base < buf->tail[0].iov_len) {
1062 subbuf->tail[0].iov_base = buf->tail[0].iov_base + base;
1063 subbuf->tail[0].iov_len = min_t(unsigned int, len,
1064 buf->tail[0].iov_len - base);
1065 len -= subbuf->tail[0].iov_len;
1068 base -= buf->tail[0].iov_len;
1069 subbuf->tail[0].iov_base = buf->tail[0].iov_base;
1070 subbuf->tail[0].iov_len = 0;
1077 EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
1080 * xdr_buf_trim - lop at most "len" bytes off the end of "buf"
1081 * @buf: buf to be trimmed
1082 * @len: number of bytes to reduce "buf" by
1084 * Trim an xdr_buf by the given number of bytes by fixing up the lengths. Note
1085 * that it's possible that we'll trim less than that amount if the xdr_buf is
1086 * too small, or if (for instance) it's all in the head and the parser has
1087 * already read too far into it.
1089 void xdr_buf_trim(struct xdr_buf *buf, unsigned int len)
1092 unsigned int trim = len;
1094 if (buf->tail[0].iov_len) {
1095 cur = min_t(size_t, buf->tail[0].iov_len, trim);
1096 buf->tail[0].iov_len -= cur;
1102 if (buf->page_len) {
1103 cur = min_t(unsigned int, buf->page_len, trim);
1104 buf->page_len -= cur;
1110 if (buf->head[0].iov_len) {
1111 cur = min_t(size_t, buf->head[0].iov_len, trim);
1112 buf->head[0].iov_len -= cur;
1116 buf->len -= (len - trim);
1118 EXPORT_SYMBOL_GPL(xdr_buf_trim);
1120 static void __read_bytes_from_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
1122 unsigned int this_len;
1124 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1125 memcpy(obj, subbuf->head[0].iov_base, this_len);
1128 this_len = min_t(unsigned int, len, subbuf->page_len);
1130 _copy_from_pages(obj, subbuf->pages, subbuf->page_base, this_len);
1133 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1134 memcpy(obj, subbuf->tail[0].iov_base, this_len);
1137 /* obj is assumed to point to allocated memory of size at least len: */
1138 int read_bytes_from_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
1140 struct xdr_buf subbuf;
1143 status = xdr_buf_subsegment(buf, &subbuf, base, len);
1146 __read_bytes_from_xdr_buf(&subbuf, obj, len);
1149 EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf);
1151 static void __write_bytes_to_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
1153 unsigned int this_len;
1155 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1156 memcpy(subbuf->head[0].iov_base, obj, this_len);
1159 this_len = min_t(unsigned int, len, subbuf->page_len);
1161 _copy_to_pages(subbuf->pages, subbuf->page_base, obj, this_len);
1164 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1165 memcpy(subbuf->tail[0].iov_base, obj, this_len);
1168 /* obj is assumed to point to allocated memory of size at least len: */
1169 int write_bytes_to_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
1171 struct xdr_buf subbuf;
1174 status = xdr_buf_subsegment(buf, &subbuf, base, len);
1177 __write_bytes_to_xdr_buf(&subbuf, obj, len);
1180 EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf);
1183 xdr_decode_word(struct xdr_buf *buf, unsigned int base, u32 *obj)
1188 status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
1191 *obj = be32_to_cpu(raw);
1194 EXPORT_SYMBOL_GPL(xdr_decode_word);
1197 xdr_encode_word(struct xdr_buf *buf, unsigned int base, u32 obj)
1199 __be32 raw = cpu_to_be32(obj);
1201 return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj));
1203 EXPORT_SYMBOL_GPL(xdr_encode_word);
1205 /* If the netobj starting offset bytes from the start of xdr_buf is contained
1206 * entirely in the head or the tail, set object to point to it; otherwise
1207 * try to find space for it at the end of the tail, copy it there, and
1208 * set obj to point to it. */
1209 int xdr_buf_read_netobj(struct xdr_buf *buf, struct xdr_netobj *obj, unsigned int offset)
1211 struct xdr_buf subbuf;
1213 if (xdr_decode_word(buf, offset, &obj->len))
1215 if (xdr_buf_subsegment(buf, &subbuf, offset + 4, obj->len))
1218 /* Is the obj contained entirely in the head? */
1219 obj->data = subbuf.head[0].iov_base;
1220 if (subbuf.head[0].iov_len == obj->len)
1222 /* ..or is the obj contained entirely in the tail? */
1223 obj->data = subbuf.tail[0].iov_base;
1224 if (subbuf.tail[0].iov_len == obj->len)
1227 /* use end of tail as storage for obj:
1228 * (We don't copy to the beginning because then we'd have
1229 * to worry about doing a potentially overlapping copy.
1230 * This assumes the object is at most half the length of the
1232 if (obj->len > buf->buflen - buf->len)
1234 if (buf->tail[0].iov_len != 0)
1235 obj->data = buf->tail[0].iov_base + buf->tail[0].iov_len;
1237 obj->data = buf->head[0].iov_base + buf->head[0].iov_len;
1238 __read_bytes_from_xdr_buf(&subbuf, obj->data, obj->len);
1241 EXPORT_SYMBOL_GPL(xdr_buf_read_netobj);
1243 /* Returns 0 on success, or else a negative error code. */
1245 xdr_xcode_array2(struct xdr_buf *buf, unsigned int base,
1246 struct xdr_array2_desc *desc, int encode)
1248 char *elem = NULL, *c;
1249 unsigned int copied = 0, todo, avail_here;
1250 struct page **ppages = NULL;
1254 if (xdr_encode_word(buf, base, desc->array_len) != 0)
1257 if (xdr_decode_word(buf, base, &desc->array_len) != 0 ||
1258 desc->array_len > desc->array_maxlen ||
1259 (unsigned long) base + 4 + desc->array_len *
1260 desc->elem_size > buf->len)
1268 todo = desc->array_len * desc->elem_size;
1271 if (todo && base < buf->head->iov_len) {
1272 c = buf->head->iov_base + base;
1273 avail_here = min_t(unsigned int, todo,
1274 buf->head->iov_len - base);
1277 while (avail_here >= desc->elem_size) {
1278 err = desc->xcode(desc, c);
1281 c += desc->elem_size;
1282 avail_here -= desc->elem_size;
1286 elem = kmalloc(desc->elem_size, GFP_KERNEL);
1292 err = desc->xcode(desc, elem);
1295 memcpy(c, elem, avail_here);
1297 memcpy(elem, c, avail_here);
1298 copied = avail_here;
1300 base = buf->head->iov_len; /* align to start of pages */
1303 /* process pages array */
1304 base -= buf->head->iov_len;
1305 if (todo && base < buf->page_len) {
1306 unsigned int avail_page;
1308 avail_here = min(todo, buf->page_len - base);
1311 base += buf->page_base;
1312 ppages = buf->pages + (base >> PAGE_SHIFT);
1314 avail_page = min_t(unsigned int, PAGE_SIZE - base,
1316 c = kmap(*ppages) + base;
1318 while (avail_here) {
1319 avail_here -= avail_page;
1320 if (copied || avail_page < desc->elem_size) {
1321 unsigned int l = min(avail_page,
1322 desc->elem_size - copied);
1324 elem = kmalloc(desc->elem_size,
1332 err = desc->xcode(desc, elem);
1336 memcpy(c, elem + copied, l);
1338 if (copied == desc->elem_size)
1341 memcpy(elem + copied, c, l);
1343 if (copied == desc->elem_size) {
1344 err = desc->xcode(desc, elem);
1353 while (avail_page >= desc->elem_size) {
1354 err = desc->xcode(desc, c);
1357 c += desc->elem_size;
1358 avail_page -= desc->elem_size;
1361 unsigned int l = min(avail_page,
1362 desc->elem_size - copied);
1364 elem = kmalloc(desc->elem_size,
1372 err = desc->xcode(desc, elem);
1376 memcpy(c, elem + copied, l);
1378 if (copied == desc->elem_size)
1381 memcpy(elem + copied, c, l);
1383 if (copied == desc->elem_size) {
1384 err = desc->xcode(desc, elem);
1397 avail_page = min(avail_here,
1398 (unsigned int) PAGE_SIZE);
1400 base = buf->page_len; /* align to start of tail */
1404 base -= buf->page_len;
1406 c = buf->tail->iov_base + base;
1408 unsigned int l = desc->elem_size - copied;
1411 memcpy(c, elem + copied, l);
1413 memcpy(elem + copied, c, l);
1414 err = desc->xcode(desc, elem);
1422 err = desc->xcode(desc, c);
1425 c += desc->elem_size;
1426 todo -= desc->elem_size;
1439 xdr_decode_array2(struct xdr_buf *buf, unsigned int base,
1440 struct xdr_array2_desc *desc)
1442 if (base >= buf->len)
1445 return xdr_xcode_array2(buf, base, desc, 0);
1447 EXPORT_SYMBOL_GPL(xdr_decode_array2);
1450 xdr_encode_array2(struct xdr_buf *buf, unsigned int base,
1451 struct xdr_array2_desc *desc)
1453 if ((unsigned long) base + 4 + desc->array_len * desc->elem_size >
1454 buf->head->iov_len + buf->page_len + buf->tail->iov_len)
1457 return xdr_xcode_array2(buf, base, desc, 1);
1459 EXPORT_SYMBOL_GPL(xdr_encode_array2);
1462 xdr_process_buf(struct xdr_buf *buf, unsigned int offset, unsigned int len,
1463 int (*actor)(struct scatterlist *, void *), void *data)
1466 unsigned int page_len, thislen, page_offset;
1467 struct scatterlist sg[1];
1469 sg_init_table(sg, 1);
1471 if (offset >= buf->head[0].iov_len) {
1472 offset -= buf->head[0].iov_len;
1474 thislen = buf->head[0].iov_len - offset;
1477 sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
1478 ret = actor(sg, data);
1487 if (offset >= buf->page_len) {
1488 offset -= buf->page_len;
1490 page_len = buf->page_len - offset;
1494 page_offset = (offset + buf->page_base) & (PAGE_SIZE - 1);
1495 i = (offset + buf->page_base) >> PAGE_SHIFT;
1496 thislen = PAGE_SIZE - page_offset;
1498 if (thislen > page_len)
1500 sg_set_page(sg, buf->pages[i], thislen, page_offset);
1501 ret = actor(sg, data);
1504 page_len -= thislen;
1507 thislen = PAGE_SIZE;
1508 } while (page_len != 0);
1513 if (offset < buf->tail[0].iov_len) {
1514 thislen = buf->tail[0].iov_len - offset;
1517 sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
1518 ret = actor(sg, data);
1526 EXPORT_SYMBOL_GPL(xdr_process_buf);