1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/net/sunrpc/xdr.c
7 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
10 #include <linux/module.h>
11 #include <linux/slab.h>
12 #include <linux/types.h>
13 #include <linux/string.h>
14 #include <linux/kernel.h>
15 #include <linux/pagemap.h>
16 #include <linux/errno.h>
17 #include <linux/sunrpc/xdr.h>
18 #include <linux/sunrpc/msg_prot.h>
19 #include <linux/bvec.h>
20 #include <trace/events/sunrpc.h>
22 static void _copy_to_pages(struct page **, size_t, const char *, size_t);
26 * XDR functions for basic NFS types
29 xdr_encode_netobj(__be32 *p, const struct xdr_netobj *obj)
31 unsigned int quadlen = XDR_QUADLEN(obj->len);
33 p[quadlen] = 0; /* zero trailing bytes */
34 *p++ = cpu_to_be32(obj->len);
35 memcpy(p, obj->data, obj->len);
36 return p + XDR_QUADLEN(obj->len);
38 EXPORT_SYMBOL_GPL(xdr_encode_netobj);
41 xdr_decode_netobj(__be32 *p, struct xdr_netobj *obj)
45 if ((len = be32_to_cpu(*p++)) > XDR_MAX_NETOBJ)
49 return p + XDR_QUADLEN(len);
51 EXPORT_SYMBOL_GPL(xdr_decode_netobj);
54 * xdr_encode_opaque_fixed - Encode fixed length opaque data
55 * @p: pointer to current position in XDR buffer.
56 * @ptr: pointer to data to encode (or NULL)
57 * @nbytes: size of data.
59 * Copy the array of data of length nbytes at ptr to the XDR buffer
60 * at position p, then align to the next 32-bit boundary by padding
61 * with zero bytes (see RFC1832).
62 * Note: if ptr is NULL, only the padding is performed.
64 * Returns the updated current XDR buffer position
67 __be32 *xdr_encode_opaque_fixed(__be32 *p, const void *ptr, unsigned int nbytes)
69 if (likely(nbytes != 0)) {
70 unsigned int quadlen = XDR_QUADLEN(nbytes);
71 unsigned int padding = (quadlen << 2) - nbytes;
74 memcpy(p, ptr, nbytes);
76 memset((char *)p + nbytes, 0, padding);
81 EXPORT_SYMBOL_GPL(xdr_encode_opaque_fixed);
84 * xdr_encode_opaque - Encode variable length opaque data
85 * @p: pointer to current position in XDR buffer.
86 * @ptr: pointer to data to encode (or NULL)
87 * @nbytes: size of data.
89 * Returns the updated current XDR buffer position
91 __be32 *xdr_encode_opaque(__be32 *p, const void *ptr, unsigned int nbytes)
93 *p++ = cpu_to_be32(nbytes);
94 return xdr_encode_opaque_fixed(p, ptr, nbytes);
96 EXPORT_SYMBOL_GPL(xdr_encode_opaque);
99 xdr_encode_string(__be32 *p, const char *string)
101 return xdr_encode_array(p, string, strlen(string));
103 EXPORT_SYMBOL_GPL(xdr_encode_string);
106 xdr_decode_string_inplace(__be32 *p, char **sp,
107 unsigned int *lenp, unsigned int maxlen)
111 len = be32_to_cpu(*p++);
116 return p + XDR_QUADLEN(len);
118 EXPORT_SYMBOL_GPL(xdr_decode_string_inplace);
121 * xdr_terminate_string - '\0'-terminate a string residing in an xdr_buf
122 * @buf: XDR buffer where string resides
123 * @len: length of string, in bytes
126 void xdr_terminate_string(const struct xdr_buf *buf, const u32 len)
130 kaddr = kmap_atomic(buf->pages[0]);
131 kaddr[buf->page_base + len] = '\0';
132 kunmap_atomic(kaddr);
134 EXPORT_SYMBOL_GPL(xdr_terminate_string);
136 size_t xdr_buf_pagecount(const struct xdr_buf *buf)
140 return (buf->page_base + buf->page_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
144 xdr_alloc_bvec(struct xdr_buf *buf, gfp_t gfp)
146 size_t i, n = xdr_buf_pagecount(buf);
148 if (n != 0 && buf->bvec == NULL) {
149 buf->bvec = kmalloc_array(n, sizeof(buf->bvec[0]), gfp);
152 for (i = 0; i < n; i++) {
153 buf->bvec[i].bv_page = buf->pages[i];
154 buf->bvec[i].bv_len = PAGE_SIZE;
155 buf->bvec[i].bv_offset = 0;
162 xdr_free_bvec(struct xdr_buf *buf)
169 * xdr_inline_pages - Prepare receive buffer for a large reply
170 * @xdr: xdr_buf into which reply will be placed
171 * @offset: expected offset where data payload will start, in bytes
172 * @pages: vector of struct page pointers
173 * @base: offset in first page where receive should start, in bytes
174 * @len: expected size of the upper layer data payload, in bytes
178 xdr_inline_pages(struct xdr_buf *xdr, unsigned int offset,
179 struct page **pages, unsigned int base, unsigned int len)
181 struct kvec *head = xdr->head;
182 struct kvec *tail = xdr->tail;
183 char *buf = (char *)head->iov_base;
184 unsigned int buflen = head->iov_len;
186 head->iov_len = offset;
189 xdr->page_base = base;
192 tail->iov_base = buf + offset;
193 tail->iov_len = buflen - offset;
196 EXPORT_SYMBOL_GPL(xdr_inline_pages);
199 * Helper routines for doing 'memmove' like operations on a struct xdr_buf
203 * _shift_data_left_pages
204 * @pages: vector of pages containing both the source and dest memory area.
205 * @pgto_base: page vector address of destination
206 * @pgfrom_base: page vector address of source
207 * @len: number of bytes to copy
209 * Note: the addresses pgto_base and pgfrom_base are both calculated in
211 * if a memory area starts at byte 'base' in page 'pages[i]',
212 * then its address is given as (i << PAGE_CACHE_SHIFT) + base
213 * Alse note: pgto_base must be < pgfrom_base, but the memory areas
214 * they point to may overlap.
217 _shift_data_left_pages(struct page **pages, size_t pgto_base,
218 size_t pgfrom_base, size_t len)
220 struct page **pgfrom, **pgto;
224 BUG_ON(pgfrom_base <= pgto_base);
229 pgto = pages + (pgto_base >> PAGE_SHIFT);
230 pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);
232 pgto_base &= ~PAGE_MASK;
233 pgfrom_base &= ~PAGE_MASK;
236 if (pgto_base >= PAGE_SIZE) {
240 if (pgfrom_base >= PAGE_SIZE){
246 if (copy > (PAGE_SIZE - pgto_base))
247 copy = PAGE_SIZE - pgto_base;
248 if (copy > (PAGE_SIZE - pgfrom_base))
249 copy = PAGE_SIZE - pgfrom_base;
251 vto = kmap_atomic(*pgto);
252 if (*pgto != *pgfrom) {
253 vfrom = kmap_atomic(*pgfrom);
254 memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);
255 kunmap_atomic(vfrom);
257 memmove(vto + pgto_base, vto + pgfrom_base, copy);
258 flush_dcache_page(*pgto);
264 } while ((len -= copy) != 0);
268 * _shift_data_right_pages
269 * @pages: vector of pages containing both the source and dest memory area.
270 * @pgto_base: page vector address of destination
271 * @pgfrom_base: page vector address of source
272 * @len: number of bytes to copy
274 * Note: the addresses pgto_base and pgfrom_base are both calculated in
276 * if a memory area starts at byte 'base' in page 'pages[i]',
277 * then its address is given as (i << PAGE_SHIFT) + base
278 * Also note: pgfrom_base must be < pgto_base, but the memory areas
279 * they point to may overlap.
282 _shift_data_right_pages(struct page **pages, size_t pgto_base,
283 size_t pgfrom_base, size_t len)
285 struct page **pgfrom, **pgto;
289 BUG_ON(pgto_base <= pgfrom_base);
297 pgto = pages + (pgto_base >> PAGE_SHIFT);
298 pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);
300 pgto_base &= ~PAGE_MASK;
301 pgfrom_base &= ~PAGE_MASK;
304 /* Are any pointers crossing a page boundary? */
305 if (pgto_base == 0) {
306 pgto_base = PAGE_SIZE;
309 if (pgfrom_base == 0) {
310 pgfrom_base = PAGE_SIZE;
315 if (copy > pgto_base)
317 if (copy > pgfrom_base)
322 vto = kmap_atomic(*pgto);
323 if (*pgto != *pgfrom) {
324 vfrom = kmap_atomic(*pgfrom);
325 memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);
326 kunmap_atomic(vfrom);
328 memmove(vto + pgto_base, vto + pgfrom_base, copy);
329 flush_dcache_page(*pgto);
332 } while ((len -= copy) != 0);
337 * @pages: array of pages
338 * @pgbase: page vector address of destination
339 * @p: pointer to source data
342 * Copies data from an arbitrary memory location into an array of pages
343 * The copy is assumed to be non-overlapping.
346 _copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len)
355 pgto = pages + (pgbase >> PAGE_SHIFT);
356 pgbase &= ~PAGE_MASK;
359 copy = PAGE_SIZE - pgbase;
363 vto = kmap_atomic(*pgto);
364 memcpy(vto + pgbase, p, copy);
372 if (pgbase == PAGE_SIZE) {
373 flush_dcache_page(*pgto);
379 flush_dcache_page(*pgto);
384 * @p: pointer to destination
385 * @pages: array of pages
386 * @pgbase: offset of source data
389 * Copies data into an arbitrary memory location from an array of pages
390 * The copy is assumed to be non-overlapping.
393 _copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
395 struct page **pgfrom;
402 pgfrom = pages + (pgbase >> PAGE_SHIFT);
403 pgbase &= ~PAGE_MASK;
406 copy = PAGE_SIZE - pgbase;
410 vfrom = kmap_atomic(*pgfrom);
411 memcpy(p, vfrom + pgbase, copy);
412 kunmap_atomic(vfrom);
415 if (pgbase == PAGE_SIZE) {
421 } while ((len -= copy) != 0);
423 EXPORT_SYMBOL_GPL(_copy_from_pages);
425 static void xdr_buf_iov_zero(const struct kvec *iov, unsigned int base,
428 if (base >= iov->iov_len)
430 if (len > iov->iov_len - base)
431 len = iov->iov_len - base;
432 memset(iov->iov_base + base, 0, len);
438 * @pgbase: beginning offset
441 static void xdr_buf_pages_zero(const struct xdr_buf *buf, unsigned int pgbase,
444 struct page **pages = buf->pages;
451 if (pgbase >= buf->page_len) {
452 xdr_buf_iov_zero(buf->tail, pgbase - buf->page_len, len);
455 if (pgbase + len > buf->page_len) {
456 xdr_buf_iov_zero(buf->tail, 0, pgbase + len - buf->page_len);
457 len = buf->page_len - pgbase;
460 pgbase += buf->page_base;
462 page = pages + (pgbase >> PAGE_SHIFT);
463 pgbase &= ~PAGE_MASK;
466 zero = PAGE_SIZE - pgbase;
470 vpage = kmap_atomic(*page);
471 memset(vpage + pgbase, 0, zero);
472 kunmap_atomic(vpage);
474 flush_dcache_page(*page);
478 } while ((len -= zero) != 0);
481 static unsigned int xdr_buf_pages_fill_sparse(const struct xdr_buf *buf,
482 unsigned int buflen, gfp_t gfp)
484 unsigned int i, npages, pagelen;
486 if (!(buf->flags & XDRBUF_SPARSE_PAGES))
488 if (buflen <= buf->head->iov_len)
490 pagelen = buflen - buf->head->iov_len;
491 if (pagelen > buf->page_len)
492 pagelen = buf->page_len;
493 npages = (pagelen + buf->page_base + PAGE_SIZE - 1) >> PAGE_SHIFT;
494 for (i = 0; i < npages; i++) {
497 buf->pages[i] = alloc_page(gfp);
498 if (likely(buf->pages[i]))
501 pagelen = i << PAGE_SHIFT;
502 if (pagelen > buf->page_base)
503 buflen += pagelen - buf->page_base;
509 static void xdr_buf_try_expand(struct xdr_buf *buf, unsigned int len)
511 struct kvec *head = buf->head;
512 struct kvec *tail = buf->tail;
513 unsigned int sum = head->iov_len + buf->page_len + tail->iov_len;
514 unsigned int free_space, newlen;
516 if (sum > buf->len) {
517 free_space = min_t(unsigned int, sum - buf->len, len);
518 newlen = xdr_buf_pages_fill_sparse(buf, buf->len + free_space,
520 free_space = newlen - buf->len;
527 if (buf->buflen > sum) {
528 /* Expand the tail buffer */
529 free_space = min_t(unsigned int, buf->buflen - sum, len);
530 tail->iov_len += free_space;
531 buf->len += free_space;
535 static void xdr_buf_tail_copy_right(const struct xdr_buf *buf,
536 unsigned int base, unsigned int len,
539 const struct kvec *tail = buf->tail;
540 unsigned int to = base + shift;
542 if (to >= tail->iov_len)
544 if (len + to > tail->iov_len)
545 len = tail->iov_len - to;
546 memmove(tail->iov_base + to, tail->iov_base + base, len);
549 static void xdr_buf_pages_copy_right(const struct xdr_buf *buf,
550 unsigned int base, unsigned int len,
553 const struct kvec *tail = buf->tail;
554 unsigned int to = base + shift;
555 unsigned int pglen = 0;
556 unsigned int talen = 0, tato = 0;
558 if (base >= buf->page_len)
560 if (len > buf->page_len - base)
561 len = buf->page_len - base;
562 if (to >= buf->page_len) {
563 tato = to - buf->page_len;
564 if (tail->iov_len >= len + tato)
566 else if (tail->iov_len > tato)
567 talen = tail->iov_len - tato;
568 } else if (len + to >= buf->page_len) {
569 pglen = buf->page_len - to;
571 if (talen > tail->iov_len)
572 talen = tail->iov_len;
576 _copy_from_pages(tail->iov_base + tato, buf->pages,
577 buf->page_base + base + pglen, talen);
578 _shift_data_right_pages(buf->pages, buf->page_base + to,
579 buf->page_base + base, pglen);
582 static void xdr_buf_head_copy_right(const struct xdr_buf *buf,
583 unsigned int base, unsigned int len,
586 const struct kvec *head = buf->head;
587 const struct kvec *tail = buf->tail;
588 unsigned int to = base + shift;
589 unsigned int pglen = 0, pgto = 0;
590 unsigned int talen = 0, tato = 0;
592 if (base >= head->iov_len)
594 if (len > head->iov_len - base)
595 len = head->iov_len - base;
596 if (to >= buf->page_len + head->iov_len) {
597 tato = to - buf->page_len - head->iov_len;
599 } else if (to >= head->iov_len) {
600 pgto = to - head->iov_len;
602 if (pgto + pglen > buf->page_len) {
603 talen = pgto + pglen - buf->page_len;
608 if (pglen > buf->page_len) {
609 talen = pglen - buf->page_len;
610 pglen = buf->page_len;
616 if (talen + tato > tail->iov_len)
617 talen = tail->iov_len > tato ? tail->iov_len - tato : 0;
618 memcpy(tail->iov_base + tato, head->iov_base + base, talen);
622 _copy_to_pages(buf->pages, buf->page_base + pgto, head->iov_base + base,
626 memmove(head->iov_base + to, head->iov_base + base, len);
629 static void xdr_buf_tail_shift_right(const struct xdr_buf *buf,
630 unsigned int base, unsigned int len,
633 const struct kvec *tail = buf->tail;
635 if (base >= tail->iov_len || !shift || !len)
637 xdr_buf_tail_copy_right(buf, base, len, shift);
640 static void xdr_buf_pages_shift_right(const struct xdr_buf *buf,
641 unsigned int base, unsigned int len,
646 if (base >= buf->page_len) {
647 xdr_buf_tail_shift_right(buf, base - buf->page_len, len, shift);
650 if (base + len > buf->page_len)
651 xdr_buf_tail_shift_right(buf, 0, base + len - buf->page_len,
653 xdr_buf_pages_copy_right(buf, base, len, shift);
656 static void xdr_buf_head_shift_right(const struct xdr_buf *buf,
657 unsigned int base, unsigned int len,
660 const struct kvec *head = buf->head;
664 if (base >= head->iov_len) {
665 xdr_buf_pages_shift_right(buf, head->iov_len - base, len,
669 if (base + len > head->iov_len)
670 xdr_buf_pages_shift_right(buf, 0, base + len - head->iov_len,
672 xdr_buf_head_copy_right(buf, base, len, shift);
675 static void xdr_buf_tail_copy_left(const struct xdr_buf *buf, unsigned int base,
676 unsigned int len, unsigned int shift)
678 const struct kvec *tail = buf->tail;
680 if (base >= tail->iov_len)
682 if (len > tail->iov_len - base)
683 len = tail->iov_len - base;
684 /* Shift data into head */
685 if (shift > buf->page_len + base) {
686 const struct kvec *head = buf->head;
688 head->iov_len + buf->page_len + base - shift;
689 unsigned int hdlen = len;
691 if (WARN_ONCE(shift > head->iov_len + buf->page_len + base,
692 "SUNRPC: Misaligned data.\n"))
694 if (hdto + hdlen > head->iov_len)
695 hdlen = head->iov_len - hdto;
696 memcpy(head->iov_base + hdto, tail->iov_base + base, hdlen);
702 /* Shift data into pages */
704 unsigned int pgto = buf->page_len + base - shift;
705 unsigned int pglen = len;
707 if (pgto + pglen > buf->page_len)
708 pglen = buf->page_len - pgto;
709 _copy_to_pages(buf->pages, buf->page_base + pgto,
710 tail->iov_base + base, pglen);
716 memmove(tail->iov_base + base - shift, tail->iov_base + base, len);
719 static void xdr_buf_pages_copy_left(const struct xdr_buf *buf,
720 unsigned int base, unsigned int len,
725 if (base >= buf->page_len)
727 if (len > buf->page_len - base)
728 len = buf->page_len - base;
729 /* Shift data into head */
731 const struct kvec *head = buf->head;
732 unsigned int hdto = head->iov_len + base - shift;
733 unsigned int hdlen = len;
735 if (WARN_ONCE(shift > head->iov_len + base,
736 "SUNRPC: Misaligned data.\n"))
738 if (hdto + hdlen > head->iov_len)
739 hdlen = head->iov_len - hdto;
740 _copy_from_pages(head->iov_base + hdto, buf->pages,
741 buf->page_base + base, hdlen);
748 _shift_data_left_pages(buf->pages, buf->page_base + pgto,
749 buf->page_base + base, len);
752 static void xdr_buf_tail_shift_left(const struct xdr_buf *buf,
753 unsigned int base, unsigned int len,
758 xdr_buf_tail_copy_left(buf, base, len, shift);
761 static void xdr_buf_pages_shift_left(const struct xdr_buf *buf,
762 unsigned int base, unsigned int len,
767 if (base >= buf->page_len) {
768 xdr_buf_tail_shift_left(buf, base - buf->page_len, len, shift);
771 xdr_buf_pages_copy_left(buf, base, len, shift);
773 if (len <= buf->page_len)
775 xdr_buf_tail_copy_left(buf, 0, len - buf->page_len, shift);
781 * @len: new length of buf->head[0]
783 * Shrinks XDR buffer's header kvec buf->head[0], setting it to
784 * 'len' bytes. The extra data is not lost, but is instead
785 * moved into the inlined pages and/or the tail.
787 static unsigned int xdr_shrink_bufhead(struct xdr_buf *buf, unsigned int len)
789 struct kvec *head = buf->head;
790 unsigned int shift, buflen = max(buf->len, len);
792 WARN_ON_ONCE(len > head->iov_len);
793 if (head->iov_len > buflen) {
794 buf->buflen -= head->iov_len - buflen;
795 head->iov_len = buflen;
797 if (len >= head->iov_len)
799 shift = head->iov_len - len;
800 xdr_buf_try_expand(buf, shift);
801 xdr_buf_head_shift_right(buf, len, buflen - len, shift);
803 buf->buflen -= shift;
809 * xdr_shrink_pagelen - shrinks buf->pages to @len bytes
811 * @len: new page buffer length
813 * The extra data is not lost, but is instead moved into buf->tail.
814 * Returns the actual number of bytes moved.
816 static unsigned int xdr_shrink_pagelen(struct xdr_buf *buf, unsigned int len)
818 unsigned int shift, buflen = buf->len - buf->head->iov_len;
820 WARN_ON_ONCE(len > buf->page_len);
821 if (buf->head->iov_len >= buf->len || len > buflen)
823 if (buf->page_len > buflen) {
824 buf->buflen -= buf->page_len - buflen;
825 buf->page_len = buflen;
827 if (len >= buf->page_len)
829 shift = buf->page_len - len;
830 xdr_buf_try_expand(buf, shift);
831 xdr_buf_pages_shift_right(buf, len, buflen - len, shift);
834 buf->buflen -= shift;
839 xdr_shift_buf(struct xdr_buf *buf, size_t len)
841 xdr_shrink_bufhead(buf, buf->head->iov_len - len);
843 EXPORT_SYMBOL_GPL(xdr_shift_buf);
846 * xdr_stream_pos - Return the current offset from the start of the xdr_stream
847 * @xdr: pointer to struct xdr_stream
849 unsigned int xdr_stream_pos(const struct xdr_stream *xdr)
851 return (unsigned int)(XDR_QUADLEN(xdr->buf->len) - xdr->nwords) << 2;
853 EXPORT_SYMBOL_GPL(xdr_stream_pos);
855 static void xdr_stream_set_pos(struct xdr_stream *xdr, unsigned int pos)
857 unsigned int blen = xdr->buf->len;
859 xdr->nwords = blen > pos ? XDR_QUADLEN(blen) - XDR_QUADLEN(pos) : 0;
862 static void xdr_stream_page_set_pos(struct xdr_stream *xdr, unsigned int pos)
864 xdr_stream_set_pos(xdr, pos + xdr->buf->head[0].iov_len);
868 * xdr_page_pos - Return the current offset from the start of the xdr pages
869 * @xdr: pointer to struct xdr_stream
871 unsigned int xdr_page_pos(const struct xdr_stream *xdr)
873 unsigned int pos = xdr_stream_pos(xdr);
875 WARN_ON(pos < xdr->buf->head[0].iov_len);
876 return pos - xdr->buf->head[0].iov_len;
878 EXPORT_SYMBOL_GPL(xdr_page_pos);
881 * xdr_init_encode - Initialize a struct xdr_stream for sending data.
882 * @xdr: pointer to xdr_stream struct
883 * @buf: pointer to XDR buffer in which to encode data
884 * @p: current pointer inside XDR buffer
885 * @rqst: pointer to controlling rpc_rqst, for debugging
887 * Note: at the moment the RPC client only passes the length of our
888 * scratch buffer in the xdr_buf's header kvec. Previously this
889 * meant we needed to call xdr_adjust_iovec() after encoding the
890 * data. With the new scheme, the xdr_stream manages the details
891 * of the buffer length, and takes care of adjusting the kvec
894 void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
895 struct rpc_rqst *rqst)
897 struct kvec *iov = buf->head;
898 int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len;
900 xdr_reset_scratch_buffer(xdr);
901 BUG_ON(scratch_len < 0);
904 xdr->p = (__be32 *)((char *)iov->iov_base + iov->iov_len);
905 xdr->end = (__be32 *)((char *)iov->iov_base + scratch_len);
906 BUG_ON(iov->iov_len > scratch_len);
908 if (p != xdr->p && p != NULL) {
911 BUG_ON(p < xdr->p || p > xdr->end);
912 len = (char *)p - (char *)xdr->p;
919 EXPORT_SYMBOL_GPL(xdr_init_encode);
922 * xdr_commit_encode - Ensure all data is written to buffer
923 * @xdr: pointer to xdr_stream
925 * We handle encoding across page boundaries by giving the caller a
926 * temporary location to write to, then later copying the data into
927 * place; xdr_commit_encode does that copying.
929 * Normally the caller doesn't need to call this directly, as the
930 * following xdr_reserve_space will do it. But an explicit call may be
931 * required at the end of encoding, or any other time when the xdr_buf
932 * data might be read.
934 inline void xdr_commit_encode(struct xdr_stream *xdr)
936 int shift = xdr->scratch.iov_len;
941 page = page_address(*xdr->page_ptr);
942 memcpy(xdr->scratch.iov_base, page, shift);
943 memmove(page, page + shift, (void *)xdr->p - page);
944 xdr_reset_scratch_buffer(xdr);
946 EXPORT_SYMBOL_GPL(xdr_commit_encode);
948 static __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr,
953 int frag1bytes, frag2bytes;
955 if (nbytes > PAGE_SIZE)
956 goto out_overflow; /* Bigger buffers require special handling */
957 if (xdr->buf->len + nbytes > xdr->buf->buflen)
958 goto out_overflow; /* Sorry, we're totally out of space */
959 frag1bytes = (xdr->end - xdr->p) << 2;
960 frag2bytes = nbytes - frag1bytes;
962 xdr->iov->iov_len += frag1bytes;
964 xdr->buf->page_len += frag1bytes;
968 * If the last encode didn't end exactly on a page boundary, the
969 * next one will straddle boundaries. Encode into the next
970 * page, then copy it back later in xdr_commit_encode. We use
971 * the "scratch" iov to track any temporarily unused fragment of
972 * space at the end of the previous buffer:
974 xdr_set_scratch_buffer(xdr, xdr->p, frag1bytes);
975 p = page_address(*xdr->page_ptr);
977 * Note this is where the next encode will start after we've
978 * shifted this one back:
980 xdr->p = (void *)p + frag2bytes;
981 space_left = xdr->buf->buflen - xdr->buf->len;
982 if (space_left - frag1bytes >= PAGE_SIZE)
983 xdr->end = (void *)p + PAGE_SIZE;
985 xdr->end = (void *)p + space_left - frag1bytes;
987 xdr->buf->page_len += frag2bytes;
988 xdr->buf->len += nbytes;
991 trace_rpc_xdr_overflow(xdr, nbytes);
996 * xdr_reserve_space - Reserve buffer space for sending
997 * @xdr: pointer to xdr_stream
998 * @nbytes: number of bytes to reserve
1000 * Checks that we have enough buffer space to encode 'nbytes' more
1001 * bytes of data. If so, update the total xdr_buf length, and
1002 * adjust the length of the current kvec.
1004 __be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
1009 xdr_commit_encode(xdr);
1010 /* align nbytes on the next 32-bit boundary */
1013 q = p + (nbytes >> 2);
1014 if (unlikely(q > xdr->end || q < p))
1015 return xdr_get_next_encode_buffer(xdr, nbytes);
1018 xdr->iov->iov_len += nbytes;
1020 xdr->buf->page_len += nbytes;
1021 xdr->buf->len += nbytes;
1024 EXPORT_SYMBOL_GPL(xdr_reserve_space);
1028 * xdr_reserve_space_vec - Reserves a large amount of buffer space for sending
1029 * @xdr: pointer to xdr_stream
1030 * @vec: pointer to a kvec array
1031 * @nbytes: number of bytes to reserve
1033 * Reserves enough buffer space to encode 'nbytes' of data and stores the
1034 * pointers in 'vec'. The size argument passed to xdr_reserve_space() is
1035 * determined based on the number of bytes remaining in the current page to
1036 * avoid invalidating iov_base pointers when xdr_commit_encode() is called.
1038 int xdr_reserve_space_vec(struct xdr_stream *xdr, struct kvec *vec, size_t nbytes)
1045 * svcrdma requires every READ payload to start somewhere
1048 if (xdr->iov == xdr->buf->head) {
1054 thislen = xdr->buf->page_len % PAGE_SIZE;
1055 thislen = min_t(size_t, nbytes, PAGE_SIZE - thislen);
1057 p = xdr_reserve_space(xdr, thislen);
1061 vec[v].iov_base = p;
1062 vec[v].iov_len = thislen;
1069 EXPORT_SYMBOL_GPL(xdr_reserve_space_vec);
1072 * xdr_truncate_encode - truncate an encode buffer
1073 * @xdr: pointer to xdr_stream
1074 * @len: new length of buffer
1076 * Truncates the xdr stream, so that xdr->buf->len == len,
1077 * and xdr->p points at offset len from the start of the buffer, and
1078 * head, tail, and page lengths are adjusted to correspond.
1080 * If this means moving xdr->p to a different buffer, we assume that
1081 * the end pointer should be set to the end of the current page,
1082 * except in the case of the head buffer when we assume the head
1083 * buffer's current length represents the end of the available buffer.
1085 * This is *not* safe to use on a buffer that already has inlined page
1086 * cache pages (as in a zero-copy server read reply), except for the
1087 * simple case of truncating from one position in the tail to another.
1090 void xdr_truncate_encode(struct xdr_stream *xdr, size_t len)
1092 struct xdr_buf *buf = xdr->buf;
1093 struct kvec *head = buf->head;
1094 struct kvec *tail = buf->tail;
1098 if (len > buf->len) {
1102 xdr_commit_encode(xdr);
1104 fraglen = min_t(int, buf->len - len, tail->iov_len);
1105 tail->iov_len -= fraglen;
1106 buf->len -= fraglen;
1107 if (tail->iov_len) {
1108 xdr->p = tail->iov_base + tail->iov_len;
1109 WARN_ON_ONCE(!xdr->end);
1110 WARN_ON_ONCE(!xdr->iov);
1113 WARN_ON_ONCE(fraglen);
1114 fraglen = min_t(int, buf->len - len, buf->page_len);
1115 buf->page_len -= fraglen;
1116 buf->len -= fraglen;
1118 new = buf->page_base + buf->page_len;
1120 xdr->page_ptr = buf->pages + (new >> PAGE_SHIFT);
1122 if (buf->page_len) {
1123 xdr->p = page_address(*xdr->page_ptr);
1124 xdr->end = (void *)xdr->p + PAGE_SIZE;
1125 xdr->p = (void *)xdr->p + (new % PAGE_SIZE);
1126 WARN_ON_ONCE(xdr->iov);
1130 xdr->end = head->iov_base + head->iov_len;
1131 /* (otherwise assume xdr->end is already set) */
1133 head->iov_len = len;
1135 xdr->p = head->iov_base + head->iov_len;
1136 xdr->iov = buf->head;
1138 EXPORT_SYMBOL(xdr_truncate_encode);
1141 * xdr_restrict_buflen - decrease available buffer space
1142 * @xdr: pointer to xdr_stream
1143 * @newbuflen: new maximum number of bytes available
1145 * Adjust our idea of how much space is available in the buffer.
1146 * If we've already used too much space in the buffer, returns -1.
1147 * If the available space is already smaller than newbuflen, returns 0
1148 * and does nothing. Otherwise, adjusts xdr->buf->buflen to newbuflen
1149 * and ensures xdr->end is set at most offset newbuflen from the start
1152 int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen)
1154 struct xdr_buf *buf = xdr->buf;
1155 int left_in_this_buf = (void *)xdr->end - (void *)xdr->p;
1156 int end_offset = buf->len + left_in_this_buf;
1158 if (newbuflen < 0 || newbuflen < buf->len)
1160 if (newbuflen > buf->buflen)
1162 if (newbuflen < end_offset)
1163 xdr->end = (void *)xdr->end + newbuflen - end_offset;
1164 buf->buflen = newbuflen;
1167 EXPORT_SYMBOL(xdr_restrict_buflen);
1170 * xdr_write_pages - Insert a list of pages into an XDR buffer for sending
1171 * @xdr: pointer to xdr_stream
1172 * @pages: list of pages
1173 * @base: offset of first byte
1174 * @len: length of data in bytes
1177 void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base,
1180 struct xdr_buf *buf = xdr->buf;
1181 struct kvec *iov = buf->tail;
1183 buf->page_base = base;
1184 buf->page_len = len;
1186 iov->iov_base = (char *)xdr->p;
1191 unsigned int pad = 4 - (len & 3);
1193 BUG_ON(xdr->p >= xdr->end);
1194 iov->iov_base = (char *)xdr->p + (len & 3);
1195 iov->iov_len += pad;
1202 EXPORT_SYMBOL_GPL(xdr_write_pages);
1204 static unsigned int xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
1205 unsigned int base, unsigned int len)
1207 if (len > iov->iov_len)
1209 if (unlikely(base > len))
1211 xdr->p = (__be32*)(iov->iov_base + base);
1212 xdr->end = (__be32*)(iov->iov_base + len);
1214 xdr->page_ptr = NULL;
1218 static unsigned int xdr_set_tail_base(struct xdr_stream *xdr,
1219 unsigned int base, unsigned int len)
1221 struct xdr_buf *buf = xdr->buf;
1223 xdr_stream_set_pos(xdr, base + buf->page_len + buf->head->iov_len);
1224 return xdr_set_iov(xdr, buf->tail, base, len);
1227 static unsigned int xdr_set_page_base(struct xdr_stream *xdr,
1228 unsigned int base, unsigned int len)
1231 unsigned int maxlen;
1236 maxlen = xdr->buf->page_len;
1244 xdr_stream_page_set_pos(xdr, base);
1245 base += xdr->buf->page_base;
1247 pgnr = base >> PAGE_SHIFT;
1248 xdr->page_ptr = &xdr->buf->pages[pgnr];
1249 kaddr = page_address(*xdr->page_ptr);
1251 pgoff = base & ~PAGE_MASK;
1252 xdr->p = (__be32*)(kaddr + pgoff);
1254 pgend = pgoff + len;
1255 if (pgend > PAGE_SIZE)
1257 xdr->end = (__be32*)(kaddr + pgend);
1262 static void xdr_set_page(struct xdr_stream *xdr, unsigned int base,
1265 if (xdr_set_page_base(xdr, base, len) == 0) {
1266 base -= xdr->buf->page_len;
1267 xdr_set_tail_base(xdr, base, len);
1271 static void xdr_set_next_page(struct xdr_stream *xdr)
1273 unsigned int newbase;
1275 newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT;
1276 newbase -= xdr->buf->page_base;
1277 if (newbase < xdr->buf->page_len)
1278 xdr_set_page_base(xdr, newbase, xdr_stream_remaining(xdr));
1280 xdr_set_tail_base(xdr, 0, xdr_stream_remaining(xdr));
1283 static bool xdr_set_next_buffer(struct xdr_stream *xdr)
1285 if (xdr->page_ptr != NULL)
1286 xdr_set_next_page(xdr);
1287 else if (xdr->iov == xdr->buf->head)
1288 xdr_set_page(xdr, 0, xdr_stream_remaining(xdr));
1289 return xdr->p != xdr->end;
1293 * xdr_init_decode - Initialize an xdr_stream for decoding data.
1294 * @xdr: pointer to xdr_stream struct
1295 * @buf: pointer to XDR buffer from which to decode data
1296 * @p: current pointer inside XDR buffer
1297 * @rqst: pointer to controlling rpc_rqst, for debugging
1299 void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
1300 struct rpc_rqst *rqst)
1303 xdr_reset_scratch_buffer(xdr);
1304 xdr->nwords = XDR_QUADLEN(buf->len);
1305 if (xdr_set_iov(xdr, buf->head, 0, buf->len) == 0 &&
1306 xdr_set_page_base(xdr, 0, buf->len) == 0)
1307 xdr_set_iov(xdr, buf->tail, 0, buf->len);
1308 if (p != NULL && p > xdr->p && xdr->end >= p) {
1309 xdr->nwords -= p - xdr->p;
1314 EXPORT_SYMBOL_GPL(xdr_init_decode);
1317 * xdr_init_decode_pages - Initialize an xdr_stream for decoding into pages
1318 * @xdr: pointer to xdr_stream struct
1319 * @buf: pointer to XDR buffer from which to decode data
1320 * @pages: list of pages to decode into
1321 * @len: length in bytes of buffer in pages
1323 void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
1324 struct page **pages, unsigned int len)
1326 memset(buf, 0, sizeof(*buf));
1328 buf->page_len = len;
1331 xdr_init_decode(xdr, buf, NULL, NULL);
1333 EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
1335 static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
1337 unsigned int nwords = XDR_QUADLEN(nbytes);
1339 __be32 *q = p + nwords;
1341 if (unlikely(nwords > xdr->nwords || q > xdr->end || q < p))
1344 xdr->nwords -= nwords;
1348 static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes)
1351 char *cpdest = xdr->scratch.iov_base;
1352 size_t cplen = (char *)xdr->end - (char *)xdr->p;
1354 if (nbytes > xdr->scratch.iov_len)
1356 p = __xdr_inline_decode(xdr, cplen);
1359 memcpy(cpdest, p, cplen);
1360 if (!xdr_set_next_buffer(xdr))
1364 p = __xdr_inline_decode(xdr, nbytes);
1367 memcpy(cpdest, p, nbytes);
1368 return xdr->scratch.iov_base;
1370 trace_rpc_xdr_overflow(xdr, nbytes);
1375 * xdr_inline_decode - Retrieve XDR data to decode
1376 * @xdr: pointer to xdr_stream struct
1377 * @nbytes: number of bytes of data to decode
1379 * Check if the input buffer is long enough to enable us to decode
1380 * 'nbytes' more bytes of data starting at the current position.
1381 * If so return the current pointer, then update the current
1384 __be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
1388 if (unlikely(nbytes == 0))
1390 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
1392 p = __xdr_inline_decode(xdr, nbytes);
1395 return xdr_copy_to_scratch(xdr, nbytes);
1397 trace_rpc_xdr_overflow(xdr, nbytes);
1400 EXPORT_SYMBOL_GPL(xdr_inline_decode);
1402 static void xdr_realign_pages(struct xdr_stream *xdr)
1404 struct xdr_buf *buf = xdr->buf;
1405 struct kvec *iov = buf->head;
1406 unsigned int cur = xdr_stream_pos(xdr);
1407 unsigned int copied;
1409 /* Realign pages to current pointer position */
1410 if (iov->iov_len > cur) {
1411 copied = xdr_shrink_bufhead(buf, cur);
1412 trace_rpc_xdr_alignment(xdr, cur, copied);
1413 xdr_set_page(xdr, 0, buf->page_len);
1417 static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len)
1419 struct xdr_buf *buf = xdr->buf;
1420 unsigned int nwords = XDR_QUADLEN(len);
1421 unsigned int copied;
1423 if (xdr->nwords == 0)
1426 xdr_realign_pages(xdr);
1427 if (nwords > xdr->nwords) {
1428 nwords = xdr->nwords;
1431 if (buf->page_len <= len)
1432 len = buf->page_len;
1433 else if (nwords < xdr->nwords) {
1434 /* Truncate page data and move it into the tail */
1435 copied = xdr_shrink_pagelen(buf, len);
1436 trace_rpc_xdr_alignment(xdr, len, copied);
1442 * xdr_read_pages - align page-based XDR data to current pointer position
1443 * @xdr: pointer to xdr_stream struct
1444 * @len: number of bytes of page data
1446 * Moves data beyond the current pointer position from the XDR head[] buffer
1447 * into the page list. Any data that lies beyond current position + @len
1448 * bytes is moved into the XDR tail[]. The xdr_stream current position is
1449 * then advanced past that data to align to the next XDR object in the tail.
1451 * Returns the number of XDR encoded bytes now contained in the pages
1453 unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
1455 unsigned int nwords = XDR_QUADLEN(len);
1456 unsigned int base, end, pglen;
1458 pglen = xdr_align_pages(xdr, nwords << 2);
1462 base = (nwords << 2) - pglen;
1463 end = xdr_stream_remaining(xdr) - pglen;
1465 xdr_set_tail_base(xdr, base, end);
1466 return len <= pglen ? len : pglen;
1468 EXPORT_SYMBOL_GPL(xdr_read_pages);
1470 unsigned int xdr_align_data(struct xdr_stream *xdr, unsigned int offset,
1471 unsigned int length)
1473 struct xdr_buf *buf = xdr->buf;
1474 unsigned int from, bytes, len;
1477 xdr_realign_pages(xdr);
1478 from = xdr_page_pos(xdr);
1480 if (from >= buf->page_len + buf->tail->iov_len)
1482 if (from + buf->head->iov_len >= buf->len)
1485 len = buf->len - buf->head->iov_len;
1487 /* We only shift data left! */
1488 if (WARN_ONCE(from < offset, "SUNRPC: misaligned data src=%u dst=%u\n",
1491 if (WARN_ONCE(offset > buf->page_len,
1492 "SUNRPC: buffer overflow. offset=%u, page_len=%u\n",
1493 offset, buf->page_len))
1496 /* Move page data to the left */
1497 shift = from - offset;
1498 xdr_buf_pages_shift_left(buf, from, len, shift);
1500 bytes = xdr_stream_remaining(xdr);
1505 xdr->buf->len -= shift;
1506 xdr_set_page(xdr, offset + length, bytes);
1509 EXPORT_SYMBOL_GPL(xdr_align_data);
1511 unsigned int xdr_expand_hole(struct xdr_stream *xdr, unsigned int offset,
1512 unsigned int length)
1514 struct xdr_buf *buf = xdr->buf;
1515 unsigned int from, to, shift;
1517 xdr_realign_pages(xdr);
1518 from = xdr_page_pos(xdr);
1519 to = xdr_align_size(offset + length);
1521 /* Could the hole be behind us? */
1523 unsigned int buflen = buf->len - buf->head->iov_len;
1525 xdr_buf_try_expand(buf, shift);
1526 xdr_buf_pages_shift_right(buf, from, buflen, shift);
1527 xdr_set_page(xdr, to, xdr_stream_remaining(xdr));
1528 } else if (to != from)
1529 xdr_align_data(xdr, to, 0);
1530 xdr_buf_pages_zero(buf, offset, length);
1534 EXPORT_SYMBOL_GPL(xdr_expand_hole);
1537 * xdr_enter_page - decode data from the XDR page
1538 * @xdr: pointer to xdr_stream struct
1539 * @len: number of bytes of page data
1541 * Moves data beyond the current pointer position from the XDR head[] buffer
1542 * into the page list. Any data that lies beyond current position + "len"
1543 * bytes is moved into the XDR tail[]. The current pointer is then
1544 * repositioned at the beginning of the first XDR page.
1546 void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
1548 len = xdr_align_pages(xdr, len);
1550 * Position current pointer at beginning of tail, and
1551 * set remaining message length.
1554 xdr_set_page_base(xdr, 0, len);
1556 EXPORT_SYMBOL_GPL(xdr_enter_page);
1558 static const struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0};
1560 void xdr_buf_from_iov(const struct kvec *iov, struct xdr_buf *buf)
1562 buf->head[0] = *iov;
1563 buf->tail[0] = empty_iov;
1565 buf->buflen = buf->len = iov->iov_len;
1567 EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
1570 * xdr_buf_subsegment - set subbuf to a portion of buf
1571 * @buf: an xdr buffer
1572 * @subbuf: the result buffer
1573 * @base: beginning of range in bytes
1574 * @len: length of range in bytes
1576 * sets @subbuf to an xdr buffer representing the portion of @buf of
1577 * length @len starting at offset @base.
1579 * @buf and @subbuf may be pointers to the same struct xdr_buf.
1581 * Returns -1 if base of length are out of bounds.
1583 int xdr_buf_subsegment(const struct xdr_buf *buf, struct xdr_buf *subbuf,
1584 unsigned int base, unsigned int len)
1586 subbuf->buflen = subbuf->len = len;
1587 if (base < buf->head[0].iov_len) {
1588 subbuf->head[0].iov_base = buf->head[0].iov_base + base;
1589 subbuf->head[0].iov_len = min_t(unsigned int, len,
1590 buf->head[0].iov_len - base);
1591 len -= subbuf->head[0].iov_len;
1594 base -= buf->head[0].iov_len;
1595 subbuf->head[0].iov_base = buf->head[0].iov_base;
1596 subbuf->head[0].iov_len = 0;
1599 if (base < buf->page_len) {
1600 subbuf->page_len = min(buf->page_len - base, len);
1601 base += buf->page_base;
1602 subbuf->page_base = base & ~PAGE_MASK;
1603 subbuf->pages = &buf->pages[base >> PAGE_SHIFT];
1604 len -= subbuf->page_len;
1607 base -= buf->page_len;
1608 subbuf->pages = buf->pages;
1609 subbuf->page_base = 0;
1610 subbuf->page_len = 0;
1613 if (base < buf->tail[0].iov_len) {
1614 subbuf->tail[0].iov_base = buf->tail[0].iov_base + base;
1615 subbuf->tail[0].iov_len = min_t(unsigned int, len,
1616 buf->tail[0].iov_len - base);
1617 len -= subbuf->tail[0].iov_len;
1620 base -= buf->tail[0].iov_len;
1621 subbuf->tail[0].iov_base = buf->tail[0].iov_base;
1622 subbuf->tail[0].iov_len = 0;
1629 EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
1632 * xdr_stream_subsegment - set @subbuf to a portion of @xdr
1633 * @xdr: an xdr_stream set up for decoding
1634 * @subbuf: the result buffer
1635 * @nbytes: length of @xdr to extract, in bytes
1637 * Sets up @subbuf to represent a portion of @xdr. The portion
1638 * starts at the current offset in @xdr, and extends for a length
1639 * of @nbytes. If this is successful, @xdr is advanced to the next
1640 * position following that portion.
1643 * %true: @subbuf has been initialized, and @xdr has been advanced.
1644 * %false: a bounds error has occurred
1646 bool xdr_stream_subsegment(struct xdr_stream *xdr, struct xdr_buf *subbuf,
1647 unsigned int nbytes)
1649 unsigned int remaining, offset, len;
1651 if (xdr_buf_subsegment(xdr->buf, subbuf, xdr_stream_pos(xdr), nbytes))
1654 if (subbuf->head[0].iov_len)
1655 if (!__xdr_inline_decode(xdr, subbuf->head[0].iov_len))
1658 remaining = subbuf->page_len;
1659 offset = subbuf->page_base;
1661 len = min_t(unsigned int, remaining, PAGE_SIZE) - offset;
1663 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
1665 if (!__xdr_inline_decode(xdr, len))
1674 EXPORT_SYMBOL_GPL(xdr_stream_subsegment);
1677 * xdr_buf_trim - lop at most "len" bytes off the end of "buf"
1678 * @buf: buf to be trimmed
1679 * @len: number of bytes to reduce "buf" by
1681 * Trim an xdr_buf by the given number of bytes by fixing up the lengths. Note
1682 * that it's possible that we'll trim less than that amount if the xdr_buf is
1683 * too small, or if (for instance) it's all in the head and the parser has
1684 * already read too far into it.
1686 void xdr_buf_trim(struct xdr_buf *buf, unsigned int len)
1689 unsigned int trim = len;
1691 if (buf->tail[0].iov_len) {
1692 cur = min_t(size_t, buf->tail[0].iov_len, trim);
1693 buf->tail[0].iov_len -= cur;
1699 if (buf->page_len) {
1700 cur = min_t(unsigned int, buf->page_len, trim);
1701 buf->page_len -= cur;
1707 if (buf->head[0].iov_len) {
1708 cur = min_t(size_t, buf->head[0].iov_len, trim);
1709 buf->head[0].iov_len -= cur;
1713 buf->len -= (len - trim);
1715 EXPORT_SYMBOL_GPL(xdr_buf_trim);
1717 static void __read_bytes_from_xdr_buf(const struct xdr_buf *subbuf,
1718 void *obj, unsigned int len)
1720 unsigned int this_len;
1722 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1723 memcpy(obj, subbuf->head[0].iov_base, this_len);
1726 this_len = min_t(unsigned int, len, subbuf->page_len);
1727 _copy_from_pages(obj, subbuf->pages, subbuf->page_base, this_len);
1730 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1731 memcpy(obj, subbuf->tail[0].iov_base, this_len);
1734 /* obj is assumed to point to allocated memory of size at least len: */
1735 int read_bytes_from_xdr_buf(const struct xdr_buf *buf, unsigned int base,
1736 void *obj, unsigned int len)
1738 struct xdr_buf subbuf;
1741 status = xdr_buf_subsegment(buf, &subbuf, base, len);
1744 __read_bytes_from_xdr_buf(&subbuf, obj, len);
1747 EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf);
1749 static void __write_bytes_to_xdr_buf(const struct xdr_buf *subbuf,
1750 void *obj, unsigned int len)
1752 unsigned int this_len;
1754 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1755 memcpy(subbuf->head[0].iov_base, obj, this_len);
1758 this_len = min_t(unsigned int, len, subbuf->page_len);
1759 _copy_to_pages(subbuf->pages, subbuf->page_base, obj, this_len);
1762 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1763 memcpy(subbuf->tail[0].iov_base, obj, this_len);
1766 /* obj is assumed to point to allocated memory of size at least len: */
1767 int write_bytes_to_xdr_buf(const struct xdr_buf *buf, unsigned int base,
1768 void *obj, unsigned int len)
1770 struct xdr_buf subbuf;
1773 status = xdr_buf_subsegment(buf, &subbuf, base, len);
1776 __write_bytes_to_xdr_buf(&subbuf, obj, len);
1779 EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf);
1781 int xdr_decode_word(const struct xdr_buf *buf, unsigned int base, u32 *obj)
1786 status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
1789 *obj = be32_to_cpu(raw);
1792 EXPORT_SYMBOL_GPL(xdr_decode_word);
1794 int xdr_encode_word(const struct xdr_buf *buf, unsigned int base, u32 obj)
1796 __be32 raw = cpu_to_be32(obj);
1798 return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj));
1800 EXPORT_SYMBOL_GPL(xdr_encode_word);
1802 /* Returns 0 on success, or else a negative error code. */
1803 static int xdr_xcode_array2(const struct xdr_buf *buf, unsigned int base,
1804 struct xdr_array2_desc *desc, int encode)
1806 char *elem = NULL, *c;
1807 unsigned int copied = 0, todo, avail_here;
1808 struct page **ppages = NULL;
1812 if (xdr_encode_word(buf, base, desc->array_len) != 0)
1815 if (xdr_decode_word(buf, base, &desc->array_len) != 0 ||
1816 desc->array_len > desc->array_maxlen ||
1817 (unsigned long) base + 4 + desc->array_len *
1818 desc->elem_size > buf->len)
1826 todo = desc->array_len * desc->elem_size;
1829 if (todo && base < buf->head->iov_len) {
1830 c = buf->head->iov_base + base;
1831 avail_here = min_t(unsigned int, todo,
1832 buf->head->iov_len - base);
1835 while (avail_here >= desc->elem_size) {
1836 err = desc->xcode(desc, c);
1839 c += desc->elem_size;
1840 avail_here -= desc->elem_size;
1844 elem = kmalloc(desc->elem_size, GFP_KERNEL);
1850 err = desc->xcode(desc, elem);
1853 memcpy(c, elem, avail_here);
1855 memcpy(elem, c, avail_here);
1856 copied = avail_here;
1858 base = buf->head->iov_len; /* align to start of pages */
1861 /* process pages array */
1862 base -= buf->head->iov_len;
1863 if (todo && base < buf->page_len) {
1864 unsigned int avail_page;
1866 avail_here = min(todo, buf->page_len - base);
1869 base += buf->page_base;
1870 ppages = buf->pages + (base >> PAGE_SHIFT);
1872 avail_page = min_t(unsigned int, PAGE_SIZE - base,
1874 c = kmap(*ppages) + base;
1876 while (avail_here) {
1877 avail_here -= avail_page;
1878 if (copied || avail_page < desc->elem_size) {
1879 unsigned int l = min(avail_page,
1880 desc->elem_size - copied);
1882 elem = kmalloc(desc->elem_size,
1890 err = desc->xcode(desc, elem);
1894 memcpy(c, elem + copied, l);
1896 if (copied == desc->elem_size)
1899 memcpy(elem + copied, c, l);
1901 if (copied == desc->elem_size) {
1902 err = desc->xcode(desc, elem);
1911 while (avail_page >= desc->elem_size) {
1912 err = desc->xcode(desc, c);
1915 c += desc->elem_size;
1916 avail_page -= desc->elem_size;
1919 unsigned int l = min(avail_page,
1920 desc->elem_size - copied);
1922 elem = kmalloc(desc->elem_size,
1930 err = desc->xcode(desc, elem);
1934 memcpy(c, elem + copied, l);
1936 if (copied == desc->elem_size)
1939 memcpy(elem + copied, c, l);
1941 if (copied == desc->elem_size) {
1942 err = desc->xcode(desc, elem);
1955 avail_page = min(avail_here,
1956 (unsigned int) PAGE_SIZE);
1958 base = buf->page_len; /* align to start of tail */
1962 base -= buf->page_len;
1964 c = buf->tail->iov_base + base;
1966 unsigned int l = desc->elem_size - copied;
1969 memcpy(c, elem + copied, l);
1971 memcpy(elem + copied, c, l);
1972 err = desc->xcode(desc, elem);
1980 err = desc->xcode(desc, c);
1983 c += desc->elem_size;
1984 todo -= desc->elem_size;
1996 int xdr_decode_array2(const struct xdr_buf *buf, unsigned int base,
1997 struct xdr_array2_desc *desc)
1999 if (base >= buf->len)
2002 return xdr_xcode_array2(buf, base, desc, 0);
2004 EXPORT_SYMBOL_GPL(xdr_decode_array2);
2006 int xdr_encode_array2(const struct xdr_buf *buf, unsigned int base,
2007 struct xdr_array2_desc *desc)
2009 if ((unsigned long) base + 4 + desc->array_len * desc->elem_size >
2010 buf->head->iov_len + buf->page_len + buf->tail->iov_len)
2013 return xdr_xcode_array2(buf, base, desc, 1);
2015 EXPORT_SYMBOL_GPL(xdr_encode_array2);
2017 int xdr_process_buf(const struct xdr_buf *buf, unsigned int offset,
2019 int (*actor)(struct scatterlist *, void *), void *data)
2022 unsigned int page_len, thislen, page_offset;
2023 struct scatterlist sg[1];
2025 sg_init_table(sg, 1);
2027 if (offset >= buf->head[0].iov_len) {
2028 offset -= buf->head[0].iov_len;
2030 thislen = buf->head[0].iov_len - offset;
2033 sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
2034 ret = actor(sg, data);
2043 if (offset >= buf->page_len) {
2044 offset -= buf->page_len;
2046 page_len = buf->page_len - offset;
2050 page_offset = (offset + buf->page_base) & (PAGE_SIZE - 1);
2051 i = (offset + buf->page_base) >> PAGE_SHIFT;
2052 thislen = PAGE_SIZE - page_offset;
2054 if (thislen > page_len)
2056 sg_set_page(sg, buf->pages[i], thislen, page_offset);
2057 ret = actor(sg, data);
2060 page_len -= thislen;
2063 thislen = PAGE_SIZE;
2064 } while (page_len != 0);
2069 if (offset < buf->tail[0].iov_len) {
2070 thislen = buf->tail[0].iov_len - offset;
2073 sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
2074 ret = actor(sg, data);
2082 EXPORT_SYMBOL_GPL(xdr_process_buf);
2085 * xdr_stream_decode_opaque - Decode variable length opaque
2086 * @xdr: pointer to xdr_stream
2087 * @ptr: location to store opaque data
2088 * @size: size of storage buffer @ptr
2091 * On success, returns size of object stored in *@ptr
2092 * %-EBADMSG on XDR buffer overflow
2093 * %-EMSGSIZE on overflow of storage buffer @ptr
2095 ssize_t xdr_stream_decode_opaque(struct xdr_stream *xdr, void *ptr, size_t size)
2100 ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
2103 memcpy(ptr, p, ret);
2106 EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque);
2109 * xdr_stream_decode_opaque_dup - Decode and duplicate variable length opaque
2110 * @xdr: pointer to xdr_stream
2111 * @ptr: location to store pointer to opaque data
2112 * @maxlen: maximum acceptable object size
2113 * @gfp_flags: GFP mask to use
2116 * On success, returns size of object stored in *@ptr
2117 * %-EBADMSG on XDR buffer overflow
2118 * %-EMSGSIZE if the size of the object would exceed @maxlen
2119 * %-ENOMEM on memory allocation failure
2121 ssize_t xdr_stream_decode_opaque_dup(struct xdr_stream *xdr, void **ptr,
2122 size_t maxlen, gfp_t gfp_flags)
2127 ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
2129 *ptr = kmemdup(p, ret, gfp_flags);
2137 EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque_dup);
2140 * xdr_stream_decode_string - Decode variable length string
2141 * @xdr: pointer to xdr_stream
2142 * @str: location to store string
2143 * @size: size of storage buffer @str
2146 * On success, returns length of NUL-terminated string stored in *@str
2147 * %-EBADMSG on XDR buffer overflow
2148 * %-EMSGSIZE on overflow of storage buffer @str
2150 ssize_t xdr_stream_decode_string(struct xdr_stream *xdr, char *str, size_t size)
2155 ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
2157 memcpy(str, p, ret);
2164 EXPORT_SYMBOL_GPL(xdr_stream_decode_string);
2167 * xdr_stream_decode_string_dup - Decode and duplicate variable length string
2168 * @xdr: pointer to xdr_stream
2169 * @str: location to store pointer to string
2170 * @maxlen: maximum acceptable string length
2171 * @gfp_flags: GFP mask to use
2174 * On success, returns length of NUL-terminated string stored in *@ptr
2175 * %-EBADMSG on XDR buffer overflow
2176 * %-EMSGSIZE if the size of the string would exceed @maxlen
2177 * %-ENOMEM on memory allocation failure
2179 ssize_t xdr_stream_decode_string_dup(struct xdr_stream *xdr, char **str,
2180 size_t maxlen, gfp_t gfp_flags)
2185 ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
2187 char *s = kmemdup_nul(p, ret, gfp_flags);
2197 EXPORT_SYMBOL_GPL(xdr_stream_decode_string_dup);