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
186 * _shift_data_right_pages
187 * @pages: vector of pages containing both the source and dest memory area.
188 * @pgto_base: page vector address of destination
189 * @pgfrom_base: page vector address of source
190 * @len: number of bytes to copy
192 * Note: the addresses pgto_base and pgfrom_base are both calculated in
194 * if a memory area starts at byte 'base' in page 'pages[i]',
195 * then its address is given as (i << PAGE_CACHE_SHIFT) + base
196 * Also note: pgfrom_base must be < pgto_base, but the memory areas
197 * they point to may overlap.
200 _shift_data_right_pages(struct page **pages, size_t pgto_base,
201 size_t pgfrom_base, size_t len)
203 struct page **pgfrom, **pgto;
207 BUG_ON(pgto_base <= pgfrom_base);
212 pgto = pages + (pgto_base >> PAGE_CACHE_SHIFT);
213 pgfrom = pages + (pgfrom_base >> PAGE_CACHE_SHIFT);
215 pgto_base &= ~PAGE_CACHE_MASK;
216 pgfrom_base &= ~PAGE_CACHE_MASK;
219 /* Are any pointers crossing a page boundary? */
220 if (pgto_base == 0) {
221 pgto_base = PAGE_CACHE_SIZE;
224 if (pgfrom_base == 0) {
225 pgfrom_base = PAGE_CACHE_SIZE;
230 if (copy > pgto_base)
232 if (copy > pgfrom_base)
237 vto = kmap_atomic(*pgto);
238 vfrom = kmap_atomic(*pgfrom);
239 memmove(vto + pgto_base, vfrom + pgfrom_base, copy);
240 flush_dcache_page(*pgto);
241 kunmap_atomic(vfrom);
244 } while ((len -= copy) != 0);
249 * @pages: array of pages
250 * @pgbase: page vector address of destination
251 * @p: pointer to source data
254 * Copies data from an arbitrary memory location into an array of pages
255 * The copy is assumed to be non-overlapping.
258 _copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len)
264 pgto = pages + (pgbase >> PAGE_CACHE_SHIFT);
265 pgbase &= ~PAGE_CACHE_MASK;
268 copy = PAGE_CACHE_SIZE - pgbase;
272 vto = kmap_atomic(*pgto);
273 memcpy(vto + pgbase, p, copy);
281 if (pgbase == PAGE_CACHE_SIZE) {
282 flush_dcache_page(*pgto);
288 flush_dcache_page(*pgto);
293 * @p: pointer to destination
294 * @pages: array of pages
295 * @pgbase: offset of source data
298 * Copies data into an arbitrary memory location from an array of pages
299 * The copy is assumed to be non-overlapping.
302 _copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
304 struct page **pgfrom;
308 pgfrom = pages + (pgbase >> PAGE_CACHE_SHIFT);
309 pgbase &= ~PAGE_CACHE_MASK;
312 copy = PAGE_CACHE_SIZE - pgbase;
316 vfrom = kmap_atomic(*pgfrom);
317 memcpy(p, vfrom + pgbase, copy);
318 kunmap_atomic(vfrom);
321 if (pgbase == PAGE_CACHE_SIZE) {
327 } while ((len -= copy) != 0);
329 EXPORT_SYMBOL_GPL(_copy_from_pages);
334 * @len: bytes to remove from buf->head[0]
336 * Shrinks XDR buffer's header kvec buf->head[0] by
337 * 'len' bytes. The extra data is not lost, but is instead
338 * moved into the inlined pages and/or the tail.
341 xdr_shrink_bufhead(struct xdr_buf *buf, size_t len)
343 struct kvec *head, *tail;
345 unsigned int pglen = buf->page_len;
349 BUG_ON (len > head->iov_len);
351 /* Shift the tail first */
352 if (tail->iov_len != 0) {
353 if (tail->iov_len > len) {
354 copy = tail->iov_len - len;
355 memmove((char *)tail->iov_base + len,
356 tail->iov_base, copy);
358 /* Copy from the inlined pages into the tail */
363 if (offs >= tail->iov_len)
365 else if (copy > tail->iov_len - offs)
366 copy = tail->iov_len - offs;
368 _copy_from_pages((char *)tail->iov_base + offs,
370 buf->page_base + pglen + offs - len,
372 /* Do we also need to copy data from the head into the tail ? */
374 offs = copy = len - pglen;
375 if (copy > tail->iov_len)
376 copy = tail->iov_len;
377 memcpy(tail->iov_base,
378 (char *)head->iov_base +
379 head->iov_len - offs,
383 /* Now handle pages */
386 _shift_data_right_pages(buf->pages,
387 buf->page_base + len,
393 _copy_to_pages(buf->pages, buf->page_base,
394 (char *)head->iov_base + head->iov_len - len,
397 head->iov_len -= len;
399 /* Have we truncated the message? */
400 if (buf->len > buf->buflen)
401 buf->len = buf->buflen;
407 * @len: bytes to remove from buf->pages
409 * Shrinks XDR buffer's page array buf->pages by
410 * 'len' bytes. The extra data is not lost, but is instead
411 * moved into the tail.
414 xdr_shrink_pagelen(struct xdr_buf *buf, size_t len)
418 unsigned int pglen = buf->page_len;
419 unsigned int tailbuf_len;
422 BUG_ON (len > pglen);
424 tailbuf_len = buf->buflen - buf->head->iov_len - buf->page_len;
426 /* Shift the tail first */
427 if (tailbuf_len != 0) {
428 unsigned int free_space = tailbuf_len - tail->iov_len;
430 if (len < free_space)
432 tail->iov_len += free_space;
435 if (tail->iov_len > len) {
436 char *p = (char *)tail->iov_base + len;
437 memmove(p, tail->iov_base, tail->iov_len - len);
439 copy = tail->iov_len;
440 /* Copy from the inlined pages into the tail */
441 _copy_from_pages((char *)tail->iov_base,
442 buf->pages, buf->page_base + pglen - len,
445 buf->page_len -= len;
447 /* Have we truncated the message? */
448 if (buf->len > buf->buflen)
449 buf->len = buf->buflen;
453 xdr_shift_buf(struct xdr_buf *buf, size_t len)
455 xdr_shrink_bufhead(buf, len);
457 EXPORT_SYMBOL_GPL(xdr_shift_buf);
460 * xdr_init_encode - Initialize a struct xdr_stream for sending data.
461 * @xdr: pointer to xdr_stream struct
462 * @buf: pointer to XDR buffer in which to encode data
463 * @p: current pointer inside XDR buffer
465 * Note: at the moment the RPC client only passes the length of our
466 * scratch buffer in the xdr_buf's header kvec. Previously this
467 * meant we needed to call xdr_adjust_iovec() after encoding the
468 * data. With the new scheme, the xdr_stream manages the details
469 * of the buffer length, and takes care of adjusting the kvec
472 void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
474 struct kvec *iov = buf->head;
475 int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len;
477 BUG_ON(scratch_len < 0);
480 xdr->p = (__be32 *)((char *)iov->iov_base + iov->iov_len);
481 xdr->end = (__be32 *)((char *)iov->iov_base + scratch_len);
482 BUG_ON(iov->iov_len > scratch_len);
484 if (p != xdr->p && p != NULL) {
487 BUG_ON(p < xdr->p || p > xdr->end);
488 len = (char *)p - (char *)xdr->p;
494 EXPORT_SYMBOL_GPL(xdr_init_encode);
497 * xdr_reserve_space - Reserve buffer space for sending
498 * @xdr: pointer to xdr_stream
499 * @nbytes: number of bytes to reserve
501 * Checks that we have enough buffer space to encode 'nbytes' more
502 * bytes of data. If so, update the total xdr_buf length, and
503 * adjust the length of the current kvec.
505 __be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
510 /* align nbytes on the next 32-bit boundary */
513 q = p + (nbytes >> 2);
514 if (unlikely(q > xdr->end || q < p))
517 xdr->iov->iov_len += nbytes;
518 xdr->buf->len += nbytes;
521 EXPORT_SYMBOL_GPL(xdr_reserve_space);
524 * xdr_write_pages - Insert a list of pages into an XDR buffer for sending
525 * @xdr: pointer to xdr_stream
526 * @pages: list of pages
527 * @base: offset of first byte
528 * @len: length of data in bytes
531 void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base,
534 struct xdr_buf *buf = xdr->buf;
535 struct kvec *iov = buf->tail;
537 buf->page_base = base;
540 iov->iov_base = (char *)xdr->p;
545 unsigned int pad = 4 - (len & 3);
547 BUG_ON(xdr->p >= xdr->end);
548 iov->iov_base = (char *)xdr->p + (len & 3);
556 EXPORT_SYMBOL_GPL(xdr_write_pages);
558 static void xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
559 __be32 *p, unsigned int len)
561 if (len > iov->iov_len)
564 p = (__be32*)iov->iov_base;
566 xdr->end = (__be32*)(iov->iov_base + len);
568 xdr->page_ptr = NULL;
571 static int xdr_set_page_base(struct xdr_stream *xdr,
572 unsigned int base, unsigned int len)
580 maxlen = xdr->buf->page_len;
587 base += xdr->buf->page_base;
589 pgnr = base >> PAGE_SHIFT;
590 xdr->page_ptr = &xdr->buf->pages[pgnr];
591 kaddr = page_address(*xdr->page_ptr);
593 pgoff = base & ~PAGE_MASK;
594 xdr->p = (__be32*)(kaddr + pgoff);
597 if (pgend > PAGE_SIZE)
599 xdr->end = (__be32*)(kaddr + pgend);
604 static void xdr_set_next_page(struct xdr_stream *xdr)
606 unsigned int newbase;
608 newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT;
609 newbase -= xdr->buf->page_base;
611 if (xdr_set_page_base(xdr, newbase, PAGE_SIZE) < 0)
612 xdr_set_iov(xdr, xdr->buf->tail, NULL, xdr->buf->len);
615 static bool xdr_set_next_buffer(struct xdr_stream *xdr)
617 if (xdr->page_ptr != NULL)
618 xdr_set_next_page(xdr);
619 else if (xdr->iov == xdr->buf->head) {
620 if (xdr_set_page_base(xdr, 0, PAGE_SIZE) < 0)
621 xdr_set_iov(xdr, xdr->buf->tail, NULL, xdr->buf->len);
623 return xdr->p != xdr->end;
627 * xdr_init_decode - Initialize an xdr_stream for decoding data.
628 * @xdr: pointer to xdr_stream struct
629 * @buf: pointer to XDR buffer from which to decode data
630 * @p: current pointer inside XDR buffer
632 void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
635 xdr->scratch.iov_base = NULL;
636 xdr->scratch.iov_len = 0;
637 if (buf->head[0].iov_len != 0)
638 xdr_set_iov(xdr, buf->head, p, buf->len);
639 else if (buf->page_len != 0)
640 xdr_set_page_base(xdr, 0, buf->len);
642 EXPORT_SYMBOL_GPL(xdr_init_decode);
645 * xdr_init_decode - Initialize an xdr_stream for decoding data.
646 * @xdr: pointer to xdr_stream struct
647 * @buf: pointer to XDR buffer from which to decode data
648 * @pages: list of pages to decode into
649 * @len: length in bytes of buffer in pages
651 void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
652 struct page **pages, unsigned int len)
654 memset(buf, 0, sizeof(*buf));
659 xdr_init_decode(xdr, buf, NULL);
661 EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
663 static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
666 __be32 *q = p + XDR_QUADLEN(nbytes);
668 if (unlikely(q > xdr->end || q < p))
675 * xdr_set_scratch_buffer - Attach a scratch buffer for decoding data.
676 * @xdr: pointer to xdr_stream struct
677 * @buf: pointer to an empty buffer
678 * @buflen: size of 'buf'
680 * The scratch buffer is used when decoding from an array of pages.
681 * If an xdr_inline_decode() call spans across page boundaries, then
682 * we copy the data into the scratch buffer in order to allow linear
685 void xdr_set_scratch_buffer(struct xdr_stream *xdr, void *buf, size_t buflen)
687 xdr->scratch.iov_base = buf;
688 xdr->scratch.iov_len = buflen;
690 EXPORT_SYMBOL_GPL(xdr_set_scratch_buffer);
692 static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes)
695 void *cpdest = xdr->scratch.iov_base;
696 size_t cplen = (char *)xdr->end - (char *)xdr->p;
698 if (nbytes > xdr->scratch.iov_len)
700 memcpy(cpdest, xdr->p, cplen);
703 if (!xdr_set_next_buffer(xdr))
705 p = __xdr_inline_decode(xdr, nbytes);
708 memcpy(cpdest, p, nbytes);
709 return xdr->scratch.iov_base;
713 * xdr_inline_decode - Retrieve XDR data to decode
714 * @xdr: pointer to xdr_stream struct
715 * @nbytes: number of bytes of data to decode
717 * Check if the input buffer is long enough to enable us to decode
718 * 'nbytes' more bytes of data starting at the current position.
719 * If so return the current pointer, then update the current
722 __be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
728 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
730 p = __xdr_inline_decode(xdr, nbytes);
733 return xdr_copy_to_scratch(xdr, nbytes);
735 EXPORT_SYMBOL_GPL(xdr_inline_decode);
738 * xdr_read_pages - Ensure page-based XDR data to decode is aligned at current pointer position
739 * @xdr: pointer to xdr_stream struct
740 * @len: number of bytes of page data
742 * Moves data beyond the current pointer position from the XDR head[] buffer
743 * into the page list. Any data that lies beyond current position + "len"
744 * bytes is moved into the XDR tail[].
746 void xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
748 struct xdr_buf *buf = xdr->buf;
754 /* Realign pages to current pointer position */
756 shift = iov->iov_len + (char *)iov->iov_base - (char *)xdr->p;
758 xdr_shrink_bufhead(buf, shift);
760 /* Truncate page data and move it into the tail */
761 if (buf->page_len > len)
762 xdr_shrink_pagelen(buf, buf->page_len - len);
763 padding = (XDR_QUADLEN(len) << 2) - len;
764 xdr->iov = iov = buf->tail;
765 /* Compute remaining message length. */
767 shift = buf->buflen - buf->len;
773 * Position current pointer at beginning of tail, and
774 * set remaining message length.
776 xdr->p = (__be32 *)((char *)iov->iov_base + padding);
777 xdr->end = (__be32 *)((char *)iov->iov_base + end);
779 EXPORT_SYMBOL_GPL(xdr_read_pages);
782 * xdr_enter_page - decode data from the XDR page
783 * @xdr: pointer to xdr_stream struct
784 * @len: number of bytes of page data
786 * Moves data beyond the current pointer position from the XDR head[] buffer
787 * into the page list. Any data that lies beyond current position + "len"
788 * bytes is moved into the XDR tail[]. The current pointer is then
789 * repositioned at the beginning of the first XDR page.
791 void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
793 xdr_read_pages(xdr, len);
795 * Position current pointer at beginning of tail, and
796 * set remaining message length.
798 xdr_set_page_base(xdr, 0, len);
800 EXPORT_SYMBOL_GPL(xdr_enter_page);
802 static struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0};
805 xdr_buf_from_iov(struct kvec *iov, struct xdr_buf *buf)
808 buf->tail[0] = empty_iov;
810 buf->buflen = buf->len = iov->iov_len;
812 EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
814 /* Sets subbuf to the portion of buf of length len beginning base bytes
815 * from the start of buf. Returns -1 if base of length are out of bounds. */
817 xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
818 unsigned int base, unsigned int len)
820 subbuf->buflen = subbuf->len = len;
821 if (base < buf->head[0].iov_len) {
822 subbuf->head[0].iov_base = buf->head[0].iov_base + base;
823 subbuf->head[0].iov_len = min_t(unsigned int, len,
824 buf->head[0].iov_len - base);
825 len -= subbuf->head[0].iov_len;
828 subbuf->head[0].iov_base = NULL;
829 subbuf->head[0].iov_len = 0;
830 base -= buf->head[0].iov_len;
833 if (base < buf->page_len) {
834 subbuf->page_len = min(buf->page_len - base, len);
835 base += buf->page_base;
836 subbuf->page_base = base & ~PAGE_CACHE_MASK;
837 subbuf->pages = &buf->pages[base >> PAGE_CACHE_SHIFT];
838 len -= subbuf->page_len;
841 base -= buf->page_len;
842 subbuf->page_len = 0;
845 if (base < buf->tail[0].iov_len) {
846 subbuf->tail[0].iov_base = buf->tail[0].iov_base + base;
847 subbuf->tail[0].iov_len = min_t(unsigned int, len,
848 buf->tail[0].iov_len - base);
849 len -= subbuf->tail[0].iov_len;
852 subbuf->tail[0].iov_base = NULL;
853 subbuf->tail[0].iov_len = 0;
854 base -= buf->tail[0].iov_len;
861 EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
863 static void __read_bytes_from_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
865 unsigned int this_len;
867 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
868 memcpy(obj, subbuf->head[0].iov_base, this_len);
871 this_len = min_t(unsigned int, len, subbuf->page_len);
873 _copy_from_pages(obj, subbuf->pages, subbuf->page_base, this_len);
876 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
877 memcpy(obj, subbuf->tail[0].iov_base, this_len);
880 /* obj is assumed to point to allocated memory of size at least len: */
881 int read_bytes_from_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
883 struct xdr_buf subbuf;
886 status = xdr_buf_subsegment(buf, &subbuf, base, len);
889 __read_bytes_from_xdr_buf(&subbuf, obj, len);
892 EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf);
894 static void __write_bytes_to_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
896 unsigned int this_len;
898 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
899 memcpy(subbuf->head[0].iov_base, obj, this_len);
902 this_len = min_t(unsigned int, len, subbuf->page_len);
904 _copy_to_pages(subbuf->pages, subbuf->page_base, obj, this_len);
907 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
908 memcpy(subbuf->tail[0].iov_base, obj, this_len);
911 /* obj is assumed to point to allocated memory of size at least len: */
912 int write_bytes_to_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
914 struct xdr_buf subbuf;
917 status = xdr_buf_subsegment(buf, &subbuf, base, len);
920 __write_bytes_to_xdr_buf(&subbuf, obj, len);
923 EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf);
926 xdr_decode_word(struct xdr_buf *buf, unsigned int base, u32 *obj)
931 status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
934 *obj = be32_to_cpu(raw);
937 EXPORT_SYMBOL_GPL(xdr_decode_word);
940 xdr_encode_word(struct xdr_buf *buf, unsigned int base, u32 obj)
942 __be32 raw = cpu_to_be32(obj);
944 return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj));
946 EXPORT_SYMBOL_GPL(xdr_encode_word);
948 /* If the netobj starting offset bytes from the start of xdr_buf is contained
949 * entirely in the head or the tail, set object to point to it; otherwise
950 * try to find space for it at the end of the tail, copy it there, and
951 * set obj to point to it. */
952 int xdr_buf_read_netobj(struct xdr_buf *buf, struct xdr_netobj *obj, unsigned int offset)
954 struct xdr_buf subbuf;
956 if (xdr_decode_word(buf, offset, &obj->len))
958 if (xdr_buf_subsegment(buf, &subbuf, offset + 4, obj->len))
961 /* Is the obj contained entirely in the head? */
962 obj->data = subbuf.head[0].iov_base;
963 if (subbuf.head[0].iov_len == obj->len)
965 /* ..or is the obj contained entirely in the tail? */
966 obj->data = subbuf.tail[0].iov_base;
967 if (subbuf.tail[0].iov_len == obj->len)
970 /* use end of tail as storage for obj:
971 * (We don't copy to the beginning because then we'd have
972 * to worry about doing a potentially overlapping copy.
973 * This assumes the object is at most half the length of the
975 if (obj->len > buf->buflen - buf->len)
977 if (buf->tail[0].iov_len != 0)
978 obj->data = buf->tail[0].iov_base + buf->tail[0].iov_len;
980 obj->data = buf->head[0].iov_base + buf->head[0].iov_len;
981 __read_bytes_from_xdr_buf(&subbuf, obj->data, obj->len);
984 EXPORT_SYMBOL_GPL(xdr_buf_read_netobj);
986 /* Returns 0 on success, or else a negative error code. */
988 xdr_xcode_array2(struct xdr_buf *buf, unsigned int base,
989 struct xdr_array2_desc *desc, int encode)
991 char *elem = NULL, *c;
992 unsigned int copied = 0, todo, avail_here;
993 struct page **ppages = NULL;
997 if (xdr_encode_word(buf, base, desc->array_len) != 0)
1000 if (xdr_decode_word(buf, base, &desc->array_len) != 0 ||
1001 desc->array_len > desc->array_maxlen ||
1002 (unsigned long) base + 4 + desc->array_len *
1003 desc->elem_size > buf->len)
1011 todo = desc->array_len * desc->elem_size;
1014 if (todo && base < buf->head->iov_len) {
1015 c = buf->head->iov_base + base;
1016 avail_here = min_t(unsigned int, todo,
1017 buf->head->iov_len - base);
1020 while (avail_here >= desc->elem_size) {
1021 err = desc->xcode(desc, c);
1024 c += desc->elem_size;
1025 avail_here -= desc->elem_size;
1029 elem = kmalloc(desc->elem_size, GFP_KERNEL);
1035 err = desc->xcode(desc, elem);
1038 memcpy(c, elem, avail_here);
1040 memcpy(elem, c, avail_here);
1041 copied = avail_here;
1043 base = buf->head->iov_len; /* align to start of pages */
1046 /* process pages array */
1047 base -= buf->head->iov_len;
1048 if (todo && base < buf->page_len) {
1049 unsigned int avail_page;
1051 avail_here = min(todo, buf->page_len - base);
1054 base += buf->page_base;
1055 ppages = buf->pages + (base >> PAGE_CACHE_SHIFT);
1056 base &= ~PAGE_CACHE_MASK;
1057 avail_page = min_t(unsigned int, PAGE_CACHE_SIZE - base,
1059 c = kmap(*ppages) + base;
1061 while (avail_here) {
1062 avail_here -= avail_page;
1063 if (copied || avail_page < desc->elem_size) {
1064 unsigned int l = min(avail_page,
1065 desc->elem_size - copied);
1067 elem = kmalloc(desc->elem_size,
1075 err = desc->xcode(desc, elem);
1079 memcpy(c, elem + copied, l);
1081 if (copied == desc->elem_size)
1084 memcpy(elem + copied, c, l);
1086 if (copied == desc->elem_size) {
1087 err = desc->xcode(desc, elem);
1096 while (avail_page >= desc->elem_size) {
1097 err = desc->xcode(desc, c);
1100 c += desc->elem_size;
1101 avail_page -= desc->elem_size;
1104 unsigned int l = min(avail_page,
1105 desc->elem_size - copied);
1107 elem = kmalloc(desc->elem_size,
1115 err = desc->xcode(desc, elem);
1119 memcpy(c, elem + copied, l);
1121 if (copied == desc->elem_size)
1124 memcpy(elem + copied, c, l);
1126 if (copied == desc->elem_size) {
1127 err = desc->xcode(desc, elem);
1140 avail_page = min(avail_here,
1141 (unsigned int) PAGE_CACHE_SIZE);
1143 base = buf->page_len; /* align to start of tail */
1147 base -= buf->page_len;
1149 c = buf->tail->iov_base + base;
1151 unsigned int l = desc->elem_size - copied;
1154 memcpy(c, elem + copied, l);
1156 memcpy(elem + copied, c, l);
1157 err = desc->xcode(desc, elem);
1165 err = desc->xcode(desc, c);
1168 c += desc->elem_size;
1169 todo -= desc->elem_size;
1182 xdr_decode_array2(struct xdr_buf *buf, unsigned int base,
1183 struct xdr_array2_desc *desc)
1185 if (base >= buf->len)
1188 return xdr_xcode_array2(buf, base, desc, 0);
1190 EXPORT_SYMBOL_GPL(xdr_decode_array2);
1193 xdr_encode_array2(struct xdr_buf *buf, unsigned int base,
1194 struct xdr_array2_desc *desc)
1196 if ((unsigned long) base + 4 + desc->array_len * desc->elem_size >
1197 buf->head->iov_len + buf->page_len + buf->tail->iov_len)
1200 return xdr_xcode_array2(buf, base, desc, 1);
1202 EXPORT_SYMBOL_GPL(xdr_encode_array2);
1205 xdr_process_buf(struct xdr_buf *buf, unsigned int offset, unsigned int len,
1206 int (*actor)(struct scatterlist *, void *), void *data)
1209 unsigned int page_len, thislen, page_offset;
1210 struct scatterlist sg[1];
1212 sg_init_table(sg, 1);
1214 if (offset >= buf->head[0].iov_len) {
1215 offset -= buf->head[0].iov_len;
1217 thislen = buf->head[0].iov_len - offset;
1220 sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
1221 ret = actor(sg, data);
1230 if (offset >= buf->page_len) {
1231 offset -= buf->page_len;
1233 page_len = buf->page_len - offset;
1237 page_offset = (offset + buf->page_base) & (PAGE_CACHE_SIZE - 1);
1238 i = (offset + buf->page_base) >> PAGE_CACHE_SHIFT;
1239 thislen = PAGE_CACHE_SIZE - page_offset;
1241 if (thislen > page_len)
1243 sg_set_page(sg, buf->pages[i], thislen, page_offset);
1244 ret = actor(sg, data);
1247 page_len -= thislen;
1250 thislen = PAGE_CACHE_SIZE;
1251 } while (page_len != 0);
1256 if (offset < buf->tail[0].iov_len) {
1257 thislen = buf->tail[0].iov_len - offset;
1260 sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
1261 ret = actor(sg, data);
1269 EXPORT_SYMBOL_GPL(xdr_process_buf);