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_encode_pages(struct xdr_buf *xdr, struct page **pages, unsigned int base,
135 struct kvec *tail = xdr->tail;
139 xdr->page_base = base;
142 p = (u32 *)xdr->head[0].iov_base + XDR_QUADLEN(xdr->head[0].iov_len);
147 unsigned int pad = 4 - (len & 3);
150 tail->iov_base = (char *)p + (len & 3);
157 EXPORT_SYMBOL_GPL(xdr_encode_pages);
160 xdr_inline_pages(struct xdr_buf *xdr, unsigned int offset,
161 struct page **pages, unsigned int base, unsigned int len)
163 struct kvec *head = xdr->head;
164 struct kvec *tail = xdr->tail;
165 char *buf = (char *)head->iov_base;
166 unsigned int buflen = head->iov_len;
168 head->iov_len = offset;
171 xdr->page_base = base;
174 tail->iov_base = buf + offset;
175 tail->iov_len = buflen - offset;
179 EXPORT_SYMBOL_GPL(xdr_inline_pages);
182 * Helper routines for doing 'memmove' like operations on a struct xdr_buf
184 * _shift_data_right_pages
185 * @pages: vector of pages containing both the source and dest memory area.
186 * @pgto_base: page vector address of destination
187 * @pgfrom_base: page vector address of source
188 * @len: number of bytes to copy
190 * Note: the addresses pgto_base and pgfrom_base are both calculated in
192 * if a memory area starts at byte 'base' in page 'pages[i]',
193 * then its address is given as (i << PAGE_CACHE_SHIFT) + base
194 * Also note: pgfrom_base must be < pgto_base, but the memory areas
195 * they point to may overlap.
198 _shift_data_right_pages(struct page **pages, size_t pgto_base,
199 size_t pgfrom_base, size_t len)
201 struct page **pgfrom, **pgto;
205 BUG_ON(pgto_base <= pgfrom_base);
210 pgto = pages + (pgto_base >> PAGE_CACHE_SHIFT);
211 pgfrom = pages + (pgfrom_base >> PAGE_CACHE_SHIFT);
213 pgto_base &= ~PAGE_CACHE_MASK;
214 pgfrom_base &= ~PAGE_CACHE_MASK;
217 /* Are any pointers crossing a page boundary? */
218 if (pgto_base == 0) {
219 pgto_base = PAGE_CACHE_SIZE;
222 if (pgfrom_base == 0) {
223 pgfrom_base = PAGE_CACHE_SIZE;
228 if (copy > pgto_base)
230 if (copy > pgfrom_base)
235 vto = kmap_atomic(*pgto);
236 if (*pgto != *pgfrom) {
237 vfrom = kmap_atomic(*pgfrom);
238 memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);
239 kunmap_atomic(vfrom);
241 memmove(vto + pgto_base, vto + pgfrom_base, copy);
242 flush_dcache_page(*pgto);
245 } while ((len -= copy) != 0);
250 * @pages: array of pages
251 * @pgbase: page vector address of destination
252 * @p: pointer to source data
255 * Copies data from an arbitrary memory location into an array of pages
256 * The copy is assumed to be non-overlapping.
259 _copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len)
265 pgto = pages + (pgbase >> PAGE_CACHE_SHIFT);
266 pgbase &= ~PAGE_CACHE_MASK;
269 copy = PAGE_CACHE_SIZE - pgbase;
273 vto = kmap_atomic(*pgto);
274 memcpy(vto + pgbase, p, copy);
282 if (pgbase == PAGE_CACHE_SIZE) {
283 flush_dcache_page(*pgto);
289 flush_dcache_page(*pgto);
294 * @p: pointer to destination
295 * @pages: array of pages
296 * @pgbase: offset of source data
299 * Copies data into an arbitrary memory location from an array of pages
300 * The copy is assumed to be non-overlapping.
303 _copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
305 struct page **pgfrom;
309 pgfrom = pages + (pgbase >> PAGE_CACHE_SHIFT);
310 pgbase &= ~PAGE_CACHE_MASK;
313 copy = PAGE_CACHE_SIZE - pgbase;
317 vfrom = kmap_atomic(*pgfrom);
318 memcpy(p, vfrom + pgbase, copy);
319 kunmap_atomic(vfrom);
322 if (pgbase == PAGE_CACHE_SIZE) {
328 } while ((len -= copy) != 0);
330 EXPORT_SYMBOL_GPL(_copy_from_pages);
335 * @len: bytes to remove from buf->head[0]
337 * Shrinks XDR buffer's header kvec buf->head[0] by
338 * 'len' bytes. The extra data is not lost, but is instead
339 * moved into the inlined pages and/or the tail.
342 xdr_shrink_bufhead(struct xdr_buf *buf, size_t len)
344 struct kvec *head, *tail;
346 unsigned int pglen = buf->page_len;
350 BUG_ON (len > head->iov_len);
352 /* Shift the tail first */
353 if (tail->iov_len != 0) {
354 if (tail->iov_len > len) {
355 copy = tail->iov_len - len;
356 memmove((char *)tail->iov_base + len,
357 tail->iov_base, copy);
359 /* Copy from the inlined pages into the tail */
364 if (offs >= tail->iov_len)
366 else if (copy > tail->iov_len - offs)
367 copy = tail->iov_len - offs;
369 _copy_from_pages((char *)tail->iov_base + offs,
371 buf->page_base + pglen + offs - len,
373 /* Do we also need to copy data from the head into the tail ? */
375 offs = copy = len - pglen;
376 if (copy > tail->iov_len)
377 copy = tail->iov_len;
378 memcpy(tail->iov_base,
379 (char *)head->iov_base +
380 head->iov_len - offs,
384 /* Now handle pages */
387 _shift_data_right_pages(buf->pages,
388 buf->page_base + len,
394 _copy_to_pages(buf->pages, buf->page_base,
395 (char *)head->iov_base + head->iov_len - len,
398 head->iov_len -= len;
400 /* Have we truncated the message? */
401 if (buf->len > buf->buflen)
402 buf->len = buf->buflen;
408 * @len: bytes to remove from buf->pages
410 * Shrinks XDR buffer's page array buf->pages by
411 * 'len' bytes. The extra data is not lost, but is instead
412 * moved into the tail.
415 xdr_shrink_pagelen(struct xdr_buf *buf, size_t len)
419 unsigned int pglen = buf->page_len;
420 unsigned int tailbuf_len;
423 BUG_ON (len > pglen);
425 tailbuf_len = buf->buflen - buf->head->iov_len - buf->page_len;
427 /* Shift the tail first */
428 if (tailbuf_len != 0) {
429 unsigned int free_space = tailbuf_len - tail->iov_len;
431 if (len < free_space)
433 tail->iov_len += free_space;
436 if (tail->iov_len > len) {
437 char *p = (char *)tail->iov_base + len;
438 memmove(p, tail->iov_base, tail->iov_len - len);
440 copy = tail->iov_len;
441 /* Copy from the inlined pages into the tail */
442 _copy_from_pages((char *)tail->iov_base,
443 buf->pages, buf->page_base + pglen - len,
446 buf->page_len -= len;
448 /* Have we truncated the message? */
449 if (buf->len > buf->buflen)
450 buf->len = buf->buflen;
454 xdr_shift_buf(struct xdr_buf *buf, size_t len)
456 xdr_shrink_bufhead(buf, len);
458 EXPORT_SYMBOL_GPL(xdr_shift_buf);
461 * xdr_init_encode - Initialize a struct xdr_stream for sending data.
462 * @xdr: pointer to xdr_stream struct
463 * @buf: pointer to XDR buffer in which to encode data
464 * @p: current pointer inside XDR buffer
466 * Note: at the moment the RPC client only passes the length of our
467 * scratch buffer in the xdr_buf's header kvec. Previously this
468 * meant we needed to call xdr_adjust_iovec() after encoding the
469 * data. With the new scheme, the xdr_stream manages the details
470 * of the buffer length, and takes care of adjusting the kvec
473 void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
475 struct kvec *iov = buf->head;
476 int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len;
478 BUG_ON(scratch_len < 0);
481 xdr->p = (__be32 *)((char *)iov->iov_base + iov->iov_len);
482 xdr->end = (__be32 *)((char *)iov->iov_base + scratch_len);
483 BUG_ON(iov->iov_len > scratch_len);
485 if (p != xdr->p && p != NULL) {
488 BUG_ON(p < xdr->p || p > xdr->end);
489 len = (char *)p - (char *)xdr->p;
495 EXPORT_SYMBOL_GPL(xdr_init_encode);
498 * xdr_reserve_space - Reserve buffer space for sending
499 * @xdr: pointer to xdr_stream
500 * @nbytes: number of bytes to reserve
502 * Checks that we have enough buffer space to encode 'nbytes' more
503 * bytes of data. If so, update the total xdr_buf length, and
504 * adjust the length of the current kvec.
506 __be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
511 /* align nbytes on the next 32-bit boundary */
514 q = p + (nbytes >> 2);
515 if (unlikely(q > xdr->end || q < p))
518 xdr->iov->iov_len += nbytes;
519 xdr->buf->len += nbytes;
522 EXPORT_SYMBOL_GPL(xdr_reserve_space);
525 * xdr_write_pages - Insert a list of pages into an XDR buffer for sending
526 * @xdr: pointer to xdr_stream
527 * @pages: list of pages
528 * @base: offset of first byte
529 * @len: length of data in bytes
532 void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base,
535 struct xdr_buf *buf = xdr->buf;
536 struct kvec *iov = buf->tail;
538 buf->page_base = base;
541 iov->iov_base = (char *)xdr->p;
546 unsigned int pad = 4 - (len & 3);
548 BUG_ON(xdr->p >= xdr->end);
549 iov->iov_base = (char *)xdr->p + (len & 3);
557 EXPORT_SYMBOL_GPL(xdr_write_pages);
559 static void xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
560 __be32 *p, unsigned int len)
562 if (len > iov->iov_len)
565 p = (__be32*)iov->iov_base;
567 xdr->end = (__be32*)(iov->iov_base + len);
569 xdr->page_ptr = NULL;
572 static int xdr_set_page_base(struct xdr_stream *xdr,
573 unsigned int base, unsigned int len)
581 maxlen = xdr->buf->page_len;
588 base += xdr->buf->page_base;
590 pgnr = base >> PAGE_SHIFT;
591 xdr->page_ptr = &xdr->buf->pages[pgnr];
592 kaddr = page_address(*xdr->page_ptr);
594 pgoff = base & ~PAGE_MASK;
595 xdr->p = (__be32*)(kaddr + pgoff);
598 if (pgend > PAGE_SIZE)
600 xdr->end = (__be32*)(kaddr + pgend);
605 static void xdr_set_next_page(struct xdr_stream *xdr)
607 unsigned int newbase;
609 newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT;
610 newbase -= xdr->buf->page_base;
612 if (xdr_set_page_base(xdr, newbase, PAGE_SIZE) < 0)
613 xdr_set_iov(xdr, xdr->buf->tail, NULL, xdr->buf->len);
616 static bool xdr_set_next_buffer(struct xdr_stream *xdr)
618 if (xdr->page_ptr != NULL)
619 xdr_set_next_page(xdr);
620 else if (xdr->iov == xdr->buf->head) {
621 if (xdr_set_page_base(xdr, 0, PAGE_SIZE) < 0)
622 xdr_set_iov(xdr, xdr->buf->tail, NULL, xdr->buf->len);
624 return xdr->p != xdr->end;
628 * xdr_init_decode - Initialize an xdr_stream for decoding data.
629 * @xdr: pointer to xdr_stream struct
630 * @buf: pointer to XDR buffer from which to decode data
631 * @p: current pointer inside XDR buffer
633 void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
636 xdr->scratch.iov_base = NULL;
637 xdr->scratch.iov_len = 0;
638 if (buf->head[0].iov_len != 0)
639 xdr_set_iov(xdr, buf->head, p, buf->len);
640 else if (buf->page_len != 0)
641 xdr_set_page_base(xdr, 0, buf->len);
643 EXPORT_SYMBOL_GPL(xdr_init_decode);
646 * xdr_init_decode - Initialize an xdr_stream for decoding data.
647 * @xdr: pointer to xdr_stream struct
648 * @buf: pointer to XDR buffer from which to decode data
649 * @pages: list of pages to decode into
650 * @len: length in bytes of buffer in pages
652 void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
653 struct page **pages, unsigned int len)
655 memset(buf, 0, sizeof(*buf));
660 xdr_init_decode(xdr, buf, NULL);
662 EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
664 static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
667 __be32 *q = p + XDR_QUADLEN(nbytes);
669 if (unlikely(q > xdr->end || q < p))
676 * xdr_set_scratch_buffer - Attach a scratch buffer for decoding data.
677 * @xdr: pointer to xdr_stream struct
678 * @buf: pointer to an empty buffer
679 * @buflen: size of 'buf'
681 * The scratch buffer is used when decoding from an array of pages.
682 * If an xdr_inline_decode() call spans across page boundaries, then
683 * we copy the data into the scratch buffer in order to allow linear
686 void xdr_set_scratch_buffer(struct xdr_stream *xdr, void *buf, size_t buflen)
688 xdr->scratch.iov_base = buf;
689 xdr->scratch.iov_len = buflen;
691 EXPORT_SYMBOL_GPL(xdr_set_scratch_buffer);
693 static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes)
696 void *cpdest = xdr->scratch.iov_base;
697 size_t cplen = (char *)xdr->end - (char *)xdr->p;
699 if (nbytes > xdr->scratch.iov_len)
701 memcpy(cpdest, xdr->p, cplen);
704 if (!xdr_set_next_buffer(xdr))
706 p = __xdr_inline_decode(xdr, nbytes);
709 memcpy(cpdest, p, nbytes);
710 return xdr->scratch.iov_base;
714 * xdr_inline_decode - Retrieve XDR data to decode
715 * @xdr: pointer to xdr_stream struct
716 * @nbytes: number of bytes of data to decode
718 * Check if the input buffer is long enough to enable us to decode
719 * 'nbytes' more bytes of data starting at the current position.
720 * If so return the current pointer, then update the current
723 __be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
729 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
731 p = __xdr_inline_decode(xdr, nbytes);
734 return xdr_copy_to_scratch(xdr, nbytes);
736 EXPORT_SYMBOL_GPL(xdr_inline_decode);
739 * xdr_read_pages - Ensure page-based XDR data to decode is aligned at current pointer position
740 * @xdr: pointer to xdr_stream struct
741 * @len: number of bytes of page data
743 * Moves data beyond the current pointer position from the XDR head[] buffer
744 * into the page list. Any data that lies beyond current position + "len"
745 * bytes is moved into the XDR tail[].
747 void xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
749 struct xdr_buf *buf = xdr->buf;
755 /* Realign pages to current pointer position */
757 shift = iov->iov_len + (char *)iov->iov_base - (char *)xdr->p;
759 xdr_shrink_bufhead(buf, shift);
761 /* Truncate page data and move it into the tail */
762 if (buf->page_len > len)
763 xdr_shrink_pagelen(buf, buf->page_len - len);
764 padding = (XDR_QUADLEN(len) << 2) - len;
765 xdr->iov = iov = buf->tail;
766 /* Compute remaining message length. */
768 shift = buf->buflen - buf->len;
774 * Position current pointer at beginning of tail, and
775 * set remaining message length.
777 xdr->p = (__be32 *)((char *)iov->iov_base + padding);
778 xdr->end = (__be32 *)((char *)iov->iov_base + end);
780 EXPORT_SYMBOL_GPL(xdr_read_pages);
783 * xdr_enter_page - decode data from the XDR page
784 * @xdr: pointer to xdr_stream struct
785 * @len: number of bytes of page data
787 * Moves data beyond the current pointer position from the XDR head[] buffer
788 * into the page list. Any data that lies beyond current position + "len"
789 * bytes is moved into the XDR tail[]. The current pointer is then
790 * repositioned at the beginning of the first XDR page.
792 void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
794 xdr_read_pages(xdr, len);
796 * Position current pointer at beginning of tail, and
797 * set remaining message length.
799 xdr_set_page_base(xdr, 0, len);
801 EXPORT_SYMBOL_GPL(xdr_enter_page);
803 static struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0};
806 xdr_buf_from_iov(struct kvec *iov, struct xdr_buf *buf)
809 buf->tail[0] = empty_iov;
811 buf->buflen = buf->len = iov->iov_len;
813 EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
815 /* Sets subbuf to the portion of buf of length len beginning base bytes
816 * from the start of buf. Returns -1 if base of length are out of bounds. */
818 xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
819 unsigned int base, unsigned int len)
821 subbuf->buflen = subbuf->len = len;
822 if (base < buf->head[0].iov_len) {
823 subbuf->head[0].iov_base = buf->head[0].iov_base + base;
824 subbuf->head[0].iov_len = min_t(unsigned int, len,
825 buf->head[0].iov_len - base);
826 len -= subbuf->head[0].iov_len;
829 subbuf->head[0].iov_base = NULL;
830 subbuf->head[0].iov_len = 0;
831 base -= buf->head[0].iov_len;
834 if (base < buf->page_len) {
835 subbuf->page_len = min(buf->page_len - base, len);
836 base += buf->page_base;
837 subbuf->page_base = base & ~PAGE_CACHE_MASK;
838 subbuf->pages = &buf->pages[base >> PAGE_CACHE_SHIFT];
839 len -= subbuf->page_len;
842 base -= buf->page_len;
843 subbuf->page_len = 0;
846 if (base < buf->tail[0].iov_len) {
847 subbuf->tail[0].iov_base = buf->tail[0].iov_base + base;
848 subbuf->tail[0].iov_len = min_t(unsigned int, len,
849 buf->tail[0].iov_len - base);
850 len -= subbuf->tail[0].iov_len;
853 subbuf->tail[0].iov_base = NULL;
854 subbuf->tail[0].iov_len = 0;
855 base -= buf->tail[0].iov_len;
862 EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
864 static void __read_bytes_from_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
866 unsigned int this_len;
868 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
869 memcpy(obj, subbuf->head[0].iov_base, this_len);
872 this_len = min_t(unsigned int, len, subbuf->page_len);
874 _copy_from_pages(obj, subbuf->pages, subbuf->page_base, this_len);
877 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
878 memcpy(obj, subbuf->tail[0].iov_base, this_len);
881 /* obj is assumed to point to allocated memory of size at least len: */
882 int read_bytes_from_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
884 struct xdr_buf subbuf;
887 status = xdr_buf_subsegment(buf, &subbuf, base, len);
890 __read_bytes_from_xdr_buf(&subbuf, obj, len);
893 EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf);
895 static void __write_bytes_to_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
897 unsigned int this_len;
899 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
900 memcpy(subbuf->head[0].iov_base, obj, this_len);
903 this_len = min_t(unsigned int, len, subbuf->page_len);
905 _copy_to_pages(subbuf->pages, subbuf->page_base, obj, this_len);
908 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
909 memcpy(subbuf->tail[0].iov_base, obj, this_len);
912 /* obj is assumed to point to allocated memory of size at least len: */
913 int write_bytes_to_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
915 struct xdr_buf subbuf;
918 status = xdr_buf_subsegment(buf, &subbuf, base, len);
921 __write_bytes_to_xdr_buf(&subbuf, obj, len);
924 EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf);
927 xdr_decode_word(struct xdr_buf *buf, unsigned int base, u32 *obj)
932 status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
935 *obj = be32_to_cpu(raw);
938 EXPORT_SYMBOL_GPL(xdr_decode_word);
941 xdr_encode_word(struct xdr_buf *buf, unsigned int base, u32 obj)
943 __be32 raw = cpu_to_be32(obj);
945 return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj));
947 EXPORT_SYMBOL_GPL(xdr_encode_word);
949 /* If the netobj starting offset bytes from the start of xdr_buf is contained
950 * entirely in the head or the tail, set object to point to it; otherwise
951 * try to find space for it at the end of the tail, copy it there, and
952 * set obj to point to it. */
953 int xdr_buf_read_netobj(struct xdr_buf *buf, struct xdr_netobj *obj, unsigned int offset)
955 struct xdr_buf subbuf;
957 if (xdr_decode_word(buf, offset, &obj->len))
959 if (xdr_buf_subsegment(buf, &subbuf, offset + 4, obj->len))
962 /* Is the obj contained entirely in the head? */
963 obj->data = subbuf.head[0].iov_base;
964 if (subbuf.head[0].iov_len == obj->len)
966 /* ..or is the obj contained entirely in the tail? */
967 obj->data = subbuf.tail[0].iov_base;
968 if (subbuf.tail[0].iov_len == obj->len)
971 /* use end of tail as storage for obj:
972 * (We don't copy to the beginning because then we'd have
973 * to worry about doing a potentially overlapping copy.
974 * This assumes the object is at most half the length of the
976 if (obj->len > buf->buflen - buf->len)
978 if (buf->tail[0].iov_len != 0)
979 obj->data = buf->tail[0].iov_base + buf->tail[0].iov_len;
981 obj->data = buf->head[0].iov_base + buf->head[0].iov_len;
982 __read_bytes_from_xdr_buf(&subbuf, obj->data, obj->len);
985 EXPORT_SYMBOL_GPL(xdr_buf_read_netobj);
987 /* Returns 0 on success, or else a negative error code. */
989 xdr_xcode_array2(struct xdr_buf *buf, unsigned int base,
990 struct xdr_array2_desc *desc, int encode)
992 char *elem = NULL, *c;
993 unsigned int copied = 0, todo, avail_here;
994 struct page **ppages = NULL;
998 if (xdr_encode_word(buf, base, desc->array_len) != 0)
1001 if (xdr_decode_word(buf, base, &desc->array_len) != 0 ||
1002 desc->array_len > desc->array_maxlen ||
1003 (unsigned long) base + 4 + desc->array_len *
1004 desc->elem_size > buf->len)
1012 todo = desc->array_len * desc->elem_size;
1015 if (todo && base < buf->head->iov_len) {
1016 c = buf->head->iov_base + base;
1017 avail_here = min_t(unsigned int, todo,
1018 buf->head->iov_len - base);
1021 while (avail_here >= desc->elem_size) {
1022 err = desc->xcode(desc, c);
1025 c += desc->elem_size;
1026 avail_here -= desc->elem_size;
1030 elem = kmalloc(desc->elem_size, GFP_KERNEL);
1036 err = desc->xcode(desc, elem);
1039 memcpy(c, elem, avail_here);
1041 memcpy(elem, c, avail_here);
1042 copied = avail_here;
1044 base = buf->head->iov_len; /* align to start of pages */
1047 /* process pages array */
1048 base -= buf->head->iov_len;
1049 if (todo && base < buf->page_len) {
1050 unsigned int avail_page;
1052 avail_here = min(todo, buf->page_len - base);
1055 base += buf->page_base;
1056 ppages = buf->pages + (base >> PAGE_CACHE_SHIFT);
1057 base &= ~PAGE_CACHE_MASK;
1058 avail_page = min_t(unsigned int, PAGE_CACHE_SIZE - base,
1060 c = kmap(*ppages) + base;
1062 while (avail_here) {
1063 avail_here -= avail_page;
1064 if (copied || avail_page < desc->elem_size) {
1065 unsigned int l = min(avail_page,
1066 desc->elem_size - copied);
1068 elem = kmalloc(desc->elem_size,
1076 err = desc->xcode(desc, elem);
1080 memcpy(c, elem + copied, l);
1082 if (copied == desc->elem_size)
1085 memcpy(elem + copied, c, l);
1087 if (copied == desc->elem_size) {
1088 err = desc->xcode(desc, elem);
1097 while (avail_page >= desc->elem_size) {
1098 err = desc->xcode(desc, c);
1101 c += desc->elem_size;
1102 avail_page -= desc->elem_size;
1105 unsigned int l = min(avail_page,
1106 desc->elem_size - copied);
1108 elem = kmalloc(desc->elem_size,
1116 err = desc->xcode(desc, elem);
1120 memcpy(c, elem + copied, l);
1122 if (copied == desc->elem_size)
1125 memcpy(elem + copied, c, l);
1127 if (copied == desc->elem_size) {
1128 err = desc->xcode(desc, elem);
1141 avail_page = min(avail_here,
1142 (unsigned int) PAGE_CACHE_SIZE);
1144 base = buf->page_len; /* align to start of tail */
1148 base -= buf->page_len;
1150 c = buf->tail->iov_base + base;
1152 unsigned int l = desc->elem_size - copied;
1155 memcpy(c, elem + copied, l);
1157 memcpy(elem + copied, c, l);
1158 err = desc->xcode(desc, elem);
1166 err = desc->xcode(desc, c);
1169 c += desc->elem_size;
1170 todo -= desc->elem_size;
1183 xdr_decode_array2(struct xdr_buf *buf, unsigned int base,
1184 struct xdr_array2_desc *desc)
1186 if (base >= buf->len)
1189 return xdr_xcode_array2(buf, base, desc, 0);
1191 EXPORT_SYMBOL_GPL(xdr_decode_array2);
1194 xdr_encode_array2(struct xdr_buf *buf, unsigned int base,
1195 struct xdr_array2_desc *desc)
1197 if ((unsigned long) base + 4 + desc->array_len * desc->elem_size >
1198 buf->head->iov_len + buf->page_len + buf->tail->iov_len)
1201 return xdr_xcode_array2(buf, base, desc, 1);
1203 EXPORT_SYMBOL_GPL(xdr_encode_array2);
1206 xdr_process_buf(struct xdr_buf *buf, unsigned int offset, unsigned int len,
1207 int (*actor)(struct scatterlist *, void *), void *data)
1210 unsigned page_len, thislen, page_offset;
1211 struct scatterlist sg[1];
1213 sg_init_table(sg, 1);
1215 if (offset >= buf->head[0].iov_len) {
1216 offset -= buf->head[0].iov_len;
1218 thislen = buf->head[0].iov_len - offset;
1221 sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
1222 ret = actor(sg, data);
1231 if (offset >= buf->page_len) {
1232 offset -= buf->page_len;
1234 page_len = buf->page_len - offset;
1238 page_offset = (offset + buf->page_base) & (PAGE_CACHE_SIZE - 1);
1239 i = (offset + buf->page_base) >> PAGE_CACHE_SHIFT;
1240 thislen = PAGE_CACHE_SIZE - page_offset;
1242 if (thislen > page_len)
1244 sg_set_page(sg, buf->pages[i], thislen, page_offset);
1245 ret = actor(sg, data);
1248 page_len -= thislen;
1251 thislen = PAGE_CACHE_SIZE;
1252 } while (page_len != 0);
1257 if (offset < buf->tail[0].iov_len) {
1258 thislen = buf->tail[0].iov_len - offset;
1261 sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
1262 ret = actor(sg, data);
1270 EXPORT_SYMBOL_GPL(xdr_process_buf);