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], KM_USER0);
126 kaddr[buf->page_base + len] = '\0';
127 kunmap_atomic(kaddr, KM_USER0);
129 EXPORT_SYMBOL(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, KM_USER0);
236 vfrom = kmap_atomic(*pgfrom, KM_USER1);
237 memmove(vto + pgto_base, vfrom + pgfrom_base, copy);
238 flush_dcache_page(*pgto);
239 kunmap_atomic(vfrom, KM_USER1);
240 kunmap_atomic(vto, KM_USER0);
242 } while ((len -= copy) != 0);
247 * @pages: array of pages
248 * @pgbase: page vector address of destination
249 * @p: pointer to source data
252 * Copies data from an arbitrary memory location into an array of pages
253 * The copy is assumed to be non-overlapping.
256 _copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len)
262 pgto = pages + (pgbase >> PAGE_CACHE_SHIFT);
263 pgbase &= ~PAGE_CACHE_MASK;
266 copy = PAGE_CACHE_SIZE - pgbase;
270 vto = kmap_atomic(*pgto, KM_USER0);
271 memcpy(vto + pgbase, p, copy);
272 kunmap_atomic(vto, KM_USER0);
279 if (pgbase == PAGE_CACHE_SIZE) {
280 flush_dcache_page(*pgto);
286 flush_dcache_page(*pgto);
291 * @p: pointer to destination
292 * @pages: array of pages
293 * @pgbase: offset of source data
296 * Copies data into an arbitrary memory location from an array of pages
297 * The copy is assumed to be non-overlapping.
300 _copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
302 struct page **pgfrom;
306 pgfrom = pages + (pgbase >> PAGE_CACHE_SHIFT);
307 pgbase &= ~PAGE_CACHE_MASK;
310 copy = PAGE_CACHE_SIZE - pgbase;
314 vfrom = kmap_atomic(*pgfrom, KM_USER0);
315 memcpy(p, vfrom + pgbase, copy);
316 kunmap_atomic(vfrom, KM_USER0);
319 if (pgbase == PAGE_CACHE_SIZE) {
325 } while ((len -= copy) != 0);
331 * @len: bytes to remove from buf->head[0]
333 * Shrinks XDR buffer's header kvec buf->head[0] by
334 * 'len' bytes. The extra data is not lost, but is instead
335 * moved into the inlined pages and/or the tail.
338 xdr_shrink_bufhead(struct xdr_buf *buf, size_t len)
340 struct kvec *head, *tail;
342 unsigned int pglen = buf->page_len;
346 BUG_ON (len > head->iov_len);
348 /* Shift the tail first */
349 if (tail->iov_len != 0) {
350 if (tail->iov_len > len) {
351 copy = tail->iov_len - len;
352 memmove((char *)tail->iov_base + len,
353 tail->iov_base, copy);
355 /* Copy from the inlined pages into the tail */
360 if (offs >= tail->iov_len)
362 else if (copy > tail->iov_len - offs)
363 copy = tail->iov_len - offs;
365 _copy_from_pages((char *)tail->iov_base + offs,
367 buf->page_base + pglen + offs - len,
369 /* Do we also need to copy data from the head into the tail ? */
371 offs = copy = len - pglen;
372 if (copy > tail->iov_len)
373 copy = tail->iov_len;
374 memcpy(tail->iov_base,
375 (char *)head->iov_base +
376 head->iov_len - offs,
380 /* Now handle pages */
383 _shift_data_right_pages(buf->pages,
384 buf->page_base + len,
390 _copy_to_pages(buf->pages, buf->page_base,
391 (char *)head->iov_base + head->iov_len - len,
394 head->iov_len -= len;
396 /* Have we truncated the message? */
397 if (buf->len > buf->buflen)
398 buf->len = buf->buflen;
404 * @len: bytes to remove from buf->pages
406 * Shrinks XDR buffer's page array buf->pages by
407 * 'len' bytes. The extra data is not lost, but is instead
408 * moved into the tail.
411 xdr_shrink_pagelen(struct xdr_buf *buf, size_t len)
415 unsigned int pglen = buf->page_len;
416 unsigned int tailbuf_len;
419 BUG_ON (len > pglen);
421 tailbuf_len = buf->buflen - buf->head->iov_len - buf->page_len;
423 /* Shift the tail first */
424 if (tailbuf_len != 0) {
425 unsigned int free_space = tailbuf_len - tail->iov_len;
427 if (len < free_space)
429 tail->iov_len += free_space;
432 if (tail->iov_len > len) {
433 char *p = (char *)tail->iov_base + len;
434 memmove(p, tail->iov_base, tail->iov_len - len);
436 copy = tail->iov_len;
437 /* Copy from the inlined pages into the tail */
438 _copy_from_pages((char *)tail->iov_base,
439 buf->pages, buf->page_base + pglen - len,
442 buf->page_len -= len;
444 /* Have we truncated the message? */
445 if (buf->len > buf->buflen)
446 buf->len = buf->buflen;
450 xdr_shift_buf(struct xdr_buf *buf, size_t len)
452 xdr_shrink_bufhead(buf, len);
454 EXPORT_SYMBOL_GPL(xdr_shift_buf);
457 * xdr_init_encode - Initialize a struct xdr_stream for sending data.
458 * @xdr: pointer to xdr_stream struct
459 * @buf: pointer to XDR buffer in which to encode data
460 * @p: current pointer inside XDR buffer
462 * Note: at the moment the RPC client only passes the length of our
463 * scratch buffer in the xdr_buf's header kvec. Previously this
464 * meant we needed to call xdr_adjust_iovec() after encoding the
465 * data. With the new scheme, the xdr_stream manages the details
466 * of the buffer length, and takes care of adjusting the kvec
469 void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
471 struct kvec *iov = buf->head;
472 int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len;
474 BUG_ON(scratch_len < 0);
477 xdr->p = (__be32 *)((char *)iov->iov_base + iov->iov_len);
478 xdr->end = (__be32 *)((char *)iov->iov_base + scratch_len);
479 BUG_ON(iov->iov_len > scratch_len);
481 if (p != xdr->p && p != NULL) {
484 BUG_ON(p < xdr->p || p > xdr->end);
485 len = (char *)p - (char *)xdr->p;
491 EXPORT_SYMBOL_GPL(xdr_init_encode);
494 * xdr_reserve_space - Reserve buffer space for sending
495 * @xdr: pointer to xdr_stream
496 * @nbytes: number of bytes to reserve
498 * Checks that we have enough buffer space to encode 'nbytes' more
499 * bytes of data. If so, update the total xdr_buf length, and
500 * adjust the length of the current kvec.
502 __be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
507 /* align nbytes on the next 32-bit boundary */
510 q = p + (nbytes >> 2);
511 if (unlikely(q > xdr->end || q < p))
514 xdr->iov->iov_len += nbytes;
515 xdr->buf->len += nbytes;
518 EXPORT_SYMBOL_GPL(xdr_reserve_space);
521 * xdr_write_pages - Insert a list of pages into an XDR buffer for sending
522 * @xdr: pointer to xdr_stream
523 * @pages: list of pages
524 * @base: offset of first byte
525 * @len: length of data in bytes
528 void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base,
531 struct xdr_buf *buf = xdr->buf;
532 struct kvec *iov = buf->tail;
534 buf->page_base = base;
537 iov->iov_base = (char *)xdr->p;
542 unsigned int pad = 4 - (len & 3);
544 BUG_ON(xdr->p >= xdr->end);
545 iov->iov_base = (char *)xdr->p + (len & 3);
553 EXPORT_SYMBOL_GPL(xdr_write_pages);
555 static void xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
556 __be32 *p, unsigned int len)
558 if (len > iov->iov_len)
561 p = (__be32*)iov->iov_base;
563 xdr->end = (__be32*)(iov->iov_base + len);
565 xdr->page_ptr = NULL;
568 static int xdr_set_page_base(struct xdr_stream *xdr,
569 unsigned int base, unsigned int len)
577 maxlen = xdr->buf->page_len;
584 base += xdr->buf->page_base;
586 pgnr = base >> PAGE_SHIFT;
587 xdr->page_ptr = &xdr->buf->pages[pgnr];
588 kaddr = page_address(*xdr->page_ptr);
590 pgoff = base & ~PAGE_MASK;
591 xdr->p = (__be32*)(kaddr + pgoff);
594 if (pgend > PAGE_SIZE)
596 xdr->end = (__be32*)(kaddr + pgend);
601 static void xdr_set_next_page(struct xdr_stream *xdr)
603 unsigned int newbase;
605 newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT;
606 newbase -= xdr->buf->page_base;
608 if (xdr_set_page_base(xdr, newbase, PAGE_SIZE) < 0)
609 xdr_set_iov(xdr, xdr->buf->tail, NULL, xdr->buf->len);
612 static bool xdr_set_next_buffer(struct xdr_stream *xdr)
614 if (xdr->page_ptr != NULL)
615 xdr_set_next_page(xdr);
616 else if (xdr->iov == xdr->buf->head) {
617 if (xdr_set_page_base(xdr, 0, PAGE_SIZE) < 0)
618 xdr_set_iov(xdr, xdr->buf->tail, NULL, xdr->buf->len);
620 return xdr->p != xdr->end;
624 * xdr_init_decode - Initialize an xdr_stream for decoding data.
625 * @xdr: pointer to xdr_stream struct
626 * @buf: pointer to XDR buffer from which to decode data
627 * @p: current pointer inside XDR buffer
629 void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
632 xdr->scratch.iov_base = NULL;
633 xdr->scratch.iov_len = 0;
634 if (buf->head[0].iov_len != 0)
635 xdr_set_iov(xdr, buf->head, p, buf->len);
636 else if (buf->page_len != 0)
637 xdr_set_page_base(xdr, 0, buf->len);
639 EXPORT_SYMBOL_GPL(xdr_init_decode);
641 static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
644 __be32 *q = p + XDR_QUADLEN(nbytes);
646 if (unlikely(q > xdr->end || q < p))
653 * xdr_set_scratch_buffer - Attach a scratch buffer for decoding data.
654 * @xdr: pointer to xdr_stream struct
655 * @buf: pointer to an empty buffer
656 * @buflen: size of 'buf'
658 * The scratch buffer is used when decoding from an array of pages.
659 * If an xdr_inline_decode() call spans across page boundaries, then
660 * we copy the data into the scratch buffer in order to allow linear
663 void xdr_set_scratch_buffer(struct xdr_stream *xdr, void *buf, size_t buflen)
665 xdr->scratch.iov_base = buf;
666 xdr->scratch.iov_len = buflen;
668 EXPORT_SYMBOL_GPL(xdr_set_scratch_buffer);
670 static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes)
673 void *cpdest = xdr->scratch.iov_base;
674 size_t cplen = (char *)xdr->end - (char *)xdr->p;
676 if (nbytes > xdr->scratch.iov_len)
678 memcpy(cpdest, xdr->p, cplen);
681 if (!xdr_set_next_buffer(xdr))
683 p = __xdr_inline_decode(xdr, nbytes);
686 memcpy(cpdest, p, nbytes);
687 return xdr->scratch.iov_base;
691 * xdr_inline_decode - Retrieve XDR data to decode
692 * @xdr: pointer to xdr_stream struct
693 * @nbytes: number of bytes of data to decode
695 * Check if the input buffer is long enough to enable us to decode
696 * 'nbytes' more bytes of data starting at the current position.
697 * If so return the current pointer, then update the current
700 __be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
706 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
708 p = __xdr_inline_decode(xdr, nbytes);
711 return xdr_copy_to_scratch(xdr, nbytes);
713 EXPORT_SYMBOL_GPL(xdr_inline_decode);
716 * xdr_read_pages - Ensure page-based XDR data to decode is aligned at current pointer position
717 * @xdr: pointer to xdr_stream struct
718 * @len: number of bytes of page data
720 * Moves data beyond the current pointer position from the XDR head[] buffer
721 * into the page list. Any data that lies beyond current position + "len"
722 * bytes is moved into the XDR tail[].
724 void xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
726 struct xdr_buf *buf = xdr->buf;
732 /* Realign pages to current pointer position */
734 shift = iov->iov_len + (char *)iov->iov_base - (char *)xdr->p;
736 xdr_shrink_bufhead(buf, shift);
738 /* Truncate page data and move it into the tail */
739 if (buf->page_len > len)
740 xdr_shrink_pagelen(buf, buf->page_len - len);
741 padding = (XDR_QUADLEN(len) << 2) - len;
742 xdr->iov = iov = buf->tail;
743 /* Compute remaining message length. */
745 shift = buf->buflen - buf->len;
751 * Position current pointer at beginning of tail, and
752 * set remaining message length.
754 xdr->p = (__be32 *)((char *)iov->iov_base + padding);
755 xdr->end = (__be32 *)((char *)iov->iov_base + end);
757 EXPORT_SYMBOL_GPL(xdr_read_pages);
760 * xdr_enter_page - decode data from the XDR page
761 * @xdr: pointer to xdr_stream struct
762 * @len: number of bytes of page data
764 * Moves data beyond the current pointer position from the XDR head[] buffer
765 * into the page list. Any data that lies beyond current position + "len"
766 * bytes is moved into the XDR tail[]. The current pointer is then
767 * repositioned at the beginning of the first XDR page.
769 void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
771 xdr_read_pages(xdr, len);
773 * Position current pointer at beginning of tail, and
774 * set remaining message length.
776 xdr_set_page_base(xdr, 0, len);
778 EXPORT_SYMBOL_GPL(xdr_enter_page);
780 static struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0};
783 xdr_buf_from_iov(struct kvec *iov, struct xdr_buf *buf)
786 buf->tail[0] = empty_iov;
788 buf->buflen = buf->len = iov->iov_len;
790 EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
792 /* Sets subbuf to the portion of buf of length len beginning base bytes
793 * from the start of buf. Returns -1 if base of length are out of bounds. */
795 xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
796 unsigned int base, unsigned int len)
798 subbuf->buflen = subbuf->len = len;
799 if (base < buf->head[0].iov_len) {
800 subbuf->head[0].iov_base = buf->head[0].iov_base + base;
801 subbuf->head[0].iov_len = min_t(unsigned int, len,
802 buf->head[0].iov_len - base);
803 len -= subbuf->head[0].iov_len;
806 subbuf->head[0].iov_base = NULL;
807 subbuf->head[0].iov_len = 0;
808 base -= buf->head[0].iov_len;
811 if (base < buf->page_len) {
812 subbuf->page_len = min(buf->page_len - base, len);
813 base += buf->page_base;
814 subbuf->page_base = base & ~PAGE_CACHE_MASK;
815 subbuf->pages = &buf->pages[base >> PAGE_CACHE_SHIFT];
816 len -= subbuf->page_len;
819 base -= buf->page_len;
820 subbuf->page_len = 0;
823 if (base < buf->tail[0].iov_len) {
824 subbuf->tail[0].iov_base = buf->tail[0].iov_base + base;
825 subbuf->tail[0].iov_len = min_t(unsigned int, len,
826 buf->tail[0].iov_len - base);
827 len -= subbuf->tail[0].iov_len;
830 subbuf->tail[0].iov_base = NULL;
831 subbuf->tail[0].iov_len = 0;
832 base -= buf->tail[0].iov_len;
839 EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
841 static void __read_bytes_from_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
843 unsigned int this_len;
845 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
846 memcpy(obj, subbuf->head[0].iov_base, this_len);
849 this_len = min_t(unsigned int, len, subbuf->page_len);
851 _copy_from_pages(obj, subbuf->pages, subbuf->page_base, this_len);
854 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
855 memcpy(obj, subbuf->tail[0].iov_base, this_len);
858 /* obj is assumed to point to allocated memory of size at least len: */
859 int read_bytes_from_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
861 struct xdr_buf subbuf;
864 status = xdr_buf_subsegment(buf, &subbuf, base, len);
867 __read_bytes_from_xdr_buf(&subbuf, obj, len);
870 EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf);
872 static void __write_bytes_to_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
874 unsigned int this_len;
876 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
877 memcpy(subbuf->head[0].iov_base, obj, this_len);
880 this_len = min_t(unsigned int, len, subbuf->page_len);
882 _copy_to_pages(subbuf->pages, subbuf->page_base, obj, this_len);
885 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
886 memcpy(subbuf->tail[0].iov_base, obj, this_len);
889 /* obj is assumed to point to allocated memory of size at least len: */
890 int write_bytes_to_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
892 struct xdr_buf subbuf;
895 status = xdr_buf_subsegment(buf, &subbuf, base, len);
898 __write_bytes_to_xdr_buf(&subbuf, obj, len);
901 EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf);
904 xdr_decode_word(struct xdr_buf *buf, unsigned int base, u32 *obj)
909 status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
912 *obj = be32_to_cpu(raw);
915 EXPORT_SYMBOL_GPL(xdr_decode_word);
918 xdr_encode_word(struct xdr_buf *buf, unsigned int base, u32 obj)
920 __be32 raw = cpu_to_be32(obj);
922 return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj));
924 EXPORT_SYMBOL_GPL(xdr_encode_word);
926 /* If the netobj starting offset bytes from the start of xdr_buf is contained
927 * entirely in the head or the tail, set object to point to it; otherwise
928 * try to find space for it at the end of the tail, copy it there, and
929 * set obj to point to it. */
930 int xdr_buf_read_netobj(struct xdr_buf *buf, struct xdr_netobj *obj, unsigned int offset)
932 struct xdr_buf subbuf;
934 if (xdr_decode_word(buf, offset, &obj->len))
936 if (xdr_buf_subsegment(buf, &subbuf, offset + 4, obj->len))
939 /* Is the obj contained entirely in the head? */
940 obj->data = subbuf.head[0].iov_base;
941 if (subbuf.head[0].iov_len == obj->len)
943 /* ..or is the obj contained entirely in the tail? */
944 obj->data = subbuf.tail[0].iov_base;
945 if (subbuf.tail[0].iov_len == obj->len)
948 /* use end of tail as storage for obj:
949 * (We don't copy to the beginning because then we'd have
950 * to worry about doing a potentially overlapping copy.
951 * This assumes the object is at most half the length of the
953 if (obj->len > buf->buflen - buf->len)
955 if (buf->tail[0].iov_len != 0)
956 obj->data = buf->tail[0].iov_base + buf->tail[0].iov_len;
958 obj->data = buf->head[0].iov_base + buf->head[0].iov_len;
959 __read_bytes_from_xdr_buf(&subbuf, obj->data, obj->len);
962 EXPORT_SYMBOL_GPL(xdr_buf_read_netobj);
964 /* Returns 0 on success, or else a negative error code. */
966 xdr_xcode_array2(struct xdr_buf *buf, unsigned int base,
967 struct xdr_array2_desc *desc, int encode)
969 char *elem = NULL, *c;
970 unsigned int copied = 0, todo, avail_here;
971 struct page **ppages = NULL;
975 if (xdr_encode_word(buf, base, desc->array_len) != 0)
978 if (xdr_decode_word(buf, base, &desc->array_len) != 0 ||
979 desc->array_len > desc->array_maxlen ||
980 (unsigned long) base + 4 + desc->array_len *
981 desc->elem_size > buf->len)
989 todo = desc->array_len * desc->elem_size;
992 if (todo && base < buf->head->iov_len) {
993 c = buf->head->iov_base + base;
994 avail_here = min_t(unsigned int, todo,
995 buf->head->iov_len - base);
998 while (avail_here >= desc->elem_size) {
999 err = desc->xcode(desc, c);
1002 c += desc->elem_size;
1003 avail_here -= desc->elem_size;
1007 elem = kmalloc(desc->elem_size, GFP_KERNEL);
1013 err = desc->xcode(desc, elem);
1016 memcpy(c, elem, avail_here);
1018 memcpy(elem, c, avail_here);
1019 copied = avail_here;
1021 base = buf->head->iov_len; /* align to start of pages */
1024 /* process pages array */
1025 base -= buf->head->iov_len;
1026 if (todo && base < buf->page_len) {
1027 unsigned int avail_page;
1029 avail_here = min(todo, buf->page_len - base);
1032 base += buf->page_base;
1033 ppages = buf->pages + (base >> PAGE_CACHE_SHIFT);
1034 base &= ~PAGE_CACHE_MASK;
1035 avail_page = min_t(unsigned int, PAGE_CACHE_SIZE - base,
1037 c = kmap(*ppages) + base;
1039 while (avail_here) {
1040 avail_here -= avail_page;
1041 if (copied || avail_page < desc->elem_size) {
1042 unsigned int l = min(avail_page,
1043 desc->elem_size - copied);
1045 elem = kmalloc(desc->elem_size,
1053 err = desc->xcode(desc, elem);
1057 memcpy(c, elem + copied, l);
1059 if (copied == desc->elem_size)
1062 memcpy(elem + copied, c, l);
1064 if (copied == desc->elem_size) {
1065 err = desc->xcode(desc, elem);
1074 while (avail_page >= desc->elem_size) {
1075 err = desc->xcode(desc, c);
1078 c += desc->elem_size;
1079 avail_page -= desc->elem_size;
1082 unsigned int l = min(avail_page,
1083 desc->elem_size - copied);
1085 elem = kmalloc(desc->elem_size,
1093 err = desc->xcode(desc, elem);
1097 memcpy(c, elem + copied, l);
1099 if (copied == desc->elem_size)
1102 memcpy(elem + copied, c, l);
1104 if (copied == desc->elem_size) {
1105 err = desc->xcode(desc, elem);
1118 avail_page = min(avail_here,
1119 (unsigned int) PAGE_CACHE_SIZE);
1121 base = buf->page_len; /* align to start of tail */
1125 base -= buf->page_len;
1127 c = buf->tail->iov_base + base;
1129 unsigned int l = desc->elem_size - copied;
1132 memcpy(c, elem + copied, l);
1134 memcpy(elem + copied, c, l);
1135 err = desc->xcode(desc, elem);
1143 err = desc->xcode(desc, c);
1146 c += desc->elem_size;
1147 todo -= desc->elem_size;
1160 xdr_decode_array2(struct xdr_buf *buf, unsigned int base,
1161 struct xdr_array2_desc *desc)
1163 if (base >= buf->len)
1166 return xdr_xcode_array2(buf, base, desc, 0);
1168 EXPORT_SYMBOL_GPL(xdr_decode_array2);
1171 xdr_encode_array2(struct xdr_buf *buf, unsigned int base,
1172 struct xdr_array2_desc *desc)
1174 if ((unsigned long) base + 4 + desc->array_len * desc->elem_size >
1175 buf->head->iov_len + buf->page_len + buf->tail->iov_len)
1178 return xdr_xcode_array2(buf, base, desc, 1);
1180 EXPORT_SYMBOL_GPL(xdr_encode_array2);
1183 xdr_process_buf(struct xdr_buf *buf, unsigned int offset, unsigned int len,
1184 int (*actor)(struct scatterlist *, void *), void *data)
1187 unsigned page_len, thislen, page_offset;
1188 struct scatterlist sg[1];
1190 sg_init_table(sg, 1);
1192 if (offset >= buf->head[0].iov_len) {
1193 offset -= buf->head[0].iov_len;
1195 thislen = buf->head[0].iov_len - offset;
1198 sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
1199 ret = actor(sg, data);
1208 if (offset >= buf->page_len) {
1209 offset -= buf->page_len;
1211 page_len = buf->page_len - offset;
1215 page_offset = (offset + buf->page_base) & (PAGE_CACHE_SIZE - 1);
1216 i = (offset + buf->page_base) >> PAGE_CACHE_SHIFT;
1217 thislen = PAGE_CACHE_SIZE - page_offset;
1219 if (thislen > page_len)
1221 sg_set_page(sg, buf->pages[i], thislen, page_offset);
1222 ret = actor(sg, data);
1225 page_len -= thislen;
1228 thislen = PAGE_CACHE_SIZE;
1229 } while (page_len != 0);
1234 if (offset < buf->tail[0].iov_len) {
1235 thislen = buf->tail[0].iov_len - offset;
1238 sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
1239 ret = actor(sg, data);
1247 EXPORT_SYMBOL_GPL(xdr_process_buf);