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 void __xdr_commit_encode(struct xdr_stream *xdr)
936 size_t shift = xdr->scratch.iov_len;
939 page = page_address(*xdr->page_ptr);
940 memcpy(xdr->scratch.iov_base, page, shift);
941 memmove(page, page + shift, (void *)xdr->p - page);
942 xdr_reset_scratch_buffer(xdr);
944 EXPORT_SYMBOL_GPL(__xdr_commit_encode);
947 * The buffer space to be reserved crosses the boundary between
948 * xdr->buf->head and xdr->buf->pages, or between two pages
949 * in xdr->buf->pages.
951 static noinline __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr,
955 int frag1bytes, frag2bytes;
958 if (nbytes > PAGE_SIZE)
959 goto out_overflow; /* Bigger buffers require special handling */
960 if (xdr->buf->len + nbytes > xdr->buf->buflen)
961 goto out_overflow; /* Sorry, we're totally out of space */
962 frag1bytes = (xdr->end - xdr->p) << 2;
963 frag2bytes = nbytes - frag1bytes;
965 xdr->iov->iov_len += frag1bytes;
967 xdr->buf->page_len += frag1bytes;
972 * If the last encode didn't end exactly on a page boundary, the
973 * next one will straddle boundaries. Encode into the next
974 * page, then copy it back later in xdr_commit_encode. We use
975 * the "scratch" iov to track any temporarily unused fragment of
976 * space at the end of the previous buffer:
978 xdr_set_scratch_buffer(xdr, xdr->p, frag1bytes);
981 * xdr->p is where the next encode will start after
982 * xdr_commit_encode() has shifted this one back:
984 p = page_address(*xdr->page_ptr);
985 xdr->p = p + frag2bytes;
986 space_left = xdr->buf->buflen - xdr->buf->len;
987 if (space_left - frag1bytes >= PAGE_SIZE)
988 xdr->end = p + PAGE_SIZE;
990 xdr->end = p + space_left - frag1bytes;
992 xdr->buf->page_len += frag2bytes;
993 xdr->buf->len += nbytes;
996 trace_rpc_xdr_overflow(xdr, nbytes);
1001 * xdr_reserve_space - Reserve buffer space for sending
1002 * @xdr: pointer to xdr_stream
1003 * @nbytes: number of bytes to reserve
1005 * Checks that we have enough buffer space to encode 'nbytes' more
1006 * bytes of data. If so, update the total xdr_buf length, and
1007 * adjust the length of the current kvec.
1009 __be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
1014 xdr_commit_encode(xdr);
1015 /* align nbytes on the next 32-bit boundary */
1018 q = p + (nbytes >> 2);
1019 if (unlikely(q > xdr->end || q < p))
1020 return xdr_get_next_encode_buffer(xdr, nbytes);
1023 xdr->iov->iov_len += nbytes;
1025 xdr->buf->page_len += nbytes;
1026 xdr->buf->len += nbytes;
1029 EXPORT_SYMBOL_GPL(xdr_reserve_space);
1033 * xdr_reserve_space_vec - Reserves a large amount of buffer space for sending
1034 * @xdr: pointer to xdr_stream
1035 * @vec: pointer to a kvec array
1036 * @nbytes: number of bytes to reserve
1038 * Reserves enough buffer space to encode 'nbytes' of data and stores the
1039 * pointers in 'vec'. The size argument passed to xdr_reserve_space() is
1040 * determined based on the number of bytes remaining in the current page to
1041 * avoid invalidating iov_base pointers when xdr_commit_encode() is called.
1043 int xdr_reserve_space_vec(struct xdr_stream *xdr, struct kvec *vec, size_t nbytes)
1050 * svcrdma requires every READ payload to start somewhere
1053 if (xdr->iov == xdr->buf->head) {
1059 thislen = xdr->buf->page_len % PAGE_SIZE;
1060 thislen = min_t(size_t, nbytes, PAGE_SIZE - thislen);
1062 p = xdr_reserve_space(xdr, thislen);
1066 vec[v].iov_base = p;
1067 vec[v].iov_len = thislen;
1074 EXPORT_SYMBOL_GPL(xdr_reserve_space_vec);
1077 * xdr_truncate_encode - truncate an encode buffer
1078 * @xdr: pointer to xdr_stream
1079 * @len: new length of buffer
1081 * Truncates the xdr stream, so that xdr->buf->len == len,
1082 * and xdr->p points at offset len from the start of the buffer, and
1083 * head, tail, and page lengths are adjusted to correspond.
1085 * If this means moving xdr->p to a different buffer, we assume that
1086 * the end pointer should be set to the end of the current page,
1087 * except in the case of the head buffer when we assume the head
1088 * buffer's current length represents the end of the available buffer.
1090 * This is *not* safe to use on a buffer that already has inlined page
1091 * cache pages (as in a zero-copy server read reply), except for the
1092 * simple case of truncating from one position in the tail to another.
1095 void xdr_truncate_encode(struct xdr_stream *xdr, size_t len)
1097 struct xdr_buf *buf = xdr->buf;
1098 struct kvec *head = buf->head;
1099 struct kvec *tail = buf->tail;
1103 if (len > buf->len) {
1107 xdr_commit_encode(xdr);
1109 fraglen = min_t(int, buf->len - len, tail->iov_len);
1110 tail->iov_len -= fraglen;
1111 buf->len -= fraglen;
1112 if (tail->iov_len) {
1113 xdr->p = tail->iov_base + tail->iov_len;
1114 WARN_ON_ONCE(!xdr->end);
1115 WARN_ON_ONCE(!xdr->iov);
1118 WARN_ON_ONCE(fraglen);
1119 fraglen = min_t(int, buf->len - len, buf->page_len);
1120 buf->page_len -= fraglen;
1121 buf->len -= fraglen;
1123 new = buf->page_base + buf->page_len;
1125 xdr->page_ptr = buf->pages + (new >> PAGE_SHIFT);
1127 if (buf->page_len) {
1128 xdr->p = page_address(*xdr->page_ptr);
1129 xdr->end = (void *)xdr->p + PAGE_SIZE;
1130 xdr->p = (void *)xdr->p + (new % PAGE_SIZE);
1131 WARN_ON_ONCE(xdr->iov);
1135 xdr->end = head->iov_base + head->iov_len;
1136 /* (otherwise assume xdr->end is already set) */
1138 head->iov_len = len;
1140 xdr->p = head->iov_base + head->iov_len;
1141 xdr->iov = buf->head;
1143 EXPORT_SYMBOL(xdr_truncate_encode);
1146 * xdr_restrict_buflen - decrease available buffer space
1147 * @xdr: pointer to xdr_stream
1148 * @newbuflen: new maximum number of bytes available
1150 * Adjust our idea of how much space is available in the buffer.
1151 * If we've already used too much space in the buffer, returns -1.
1152 * If the available space is already smaller than newbuflen, returns 0
1153 * and does nothing. Otherwise, adjusts xdr->buf->buflen to newbuflen
1154 * and ensures xdr->end is set at most offset newbuflen from the start
1157 int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen)
1159 struct xdr_buf *buf = xdr->buf;
1160 int left_in_this_buf = (void *)xdr->end - (void *)xdr->p;
1161 int end_offset = buf->len + left_in_this_buf;
1163 if (newbuflen < 0 || newbuflen < buf->len)
1165 if (newbuflen > buf->buflen)
1167 if (newbuflen < end_offset)
1168 xdr->end = (void *)xdr->end + newbuflen - end_offset;
1169 buf->buflen = newbuflen;
1172 EXPORT_SYMBOL(xdr_restrict_buflen);
1175 * xdr_write_pages - Insert a list of pages into an XDR buffer for sending
1176 * @xdr: pointer to xdr_stream
1177 * @pages: list of pages
1178 * @base: offset of first byte
1179 * @len: length of data in bytes
1182 void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base,
1185 struct xdr_buf *buf = xdr->buf;
1186 struct kvec *iov = buf->tail;
1188 buf->page_base = base;
1189 buf->page_len = len;
1191 iov->iov_base = (char *)xdr->p;
1196 unsigned int pad = 4 - (len & 3);
1198 BUG_ON(xdr->p >= xdr->end);
1199 iov->iov_base = (char *)xdr->p + (len & 3);
1200 iov->iov_len += pad;
1207 EXPORT_SYMBOL_GPL(xdr_write_pages);
1209 static unsigned int xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
1210 unsigned int base, unsigned int len)
1212 if (len > iov->iov_len)
1214 if (unlikely(base > len))
1216 xdr->p = (__be32*)(iov->iov_base + base);
1217 xdr->end = (__be32*)(iov->iov_base + len);
1219 xdr->page_ptr = NULL;
1223 static unsigned int xdr_set_tail_base(struct xdr_stream *xdr,
1224 unsigned int base, unsigned int len)
1226 struct xdr_buf *buf = xdr->buf;
1228 xdr_stream_set_pos(xdr, base + buf->page_len + buf->head->iov_len);
1229 return xdr_set_iov(xdr, buf->tail, base, len);
1232 static unsigned int xdr_set_page_base(struct xdr_stream *xdr,
1233 unsigned int base, unsigned int len)
1236 unsigned int maxlen;
1241 maxlen = xdr->buf->page_len;
1249 xdr_stream_page_set_pos(xdr, base);
1250 base += xdr->buf->page_base;
1252 pgnr = base >> PAGE_SHIFT;
1253 xdr->page_ptr = &xdr->buf->pages[pgnr];
1254 kaddr = page_address(*xdr->page_ptr);
1256 pgoff = base & ~PAGE_MASK;
1257 xdr->p = (__be32*)(kaddr + pgoff);
1259 pgend = pgoff + len;
1260 if (pgend > PAGE_SIZE)
1262 xdr->end = (__be32*)(kaddr + pgend);
1267 static void xdr_set_page(struct xdr_stream *xdr, unsigned int base,
1270 if (xdr_set_page_base(xdr, base, len) == 0) {
1271 base -= xdr->buf->page_len;
1272 xdr_set_tail_base(xdr, base, len);
1276 static void xdr_set_next_page(struct xdr_stream *xdr)
1278 unsigned int newbase;
1280 newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT;
1281 newbase -= xdr->buf->page_base;
1282 if (newbase < xdr->buf->page_len)
1283 xdr_set_page_base(xdr, newbase, xdr_stream_remaining(xdr));
1285 xdr_set_tail_base(xdr, 0, xdr_stream_remaining(xdr));
1288 static bool xdr_set_next_buffer(struct xdr_stream *xdr)
1290 if (xdr->page_ptr != NULL)
1291 xdr_set_next_page(xdr);
1292 else if (xdr->iov == xdr->buf->head)
1293 xdr_set_page(xdr, 0, xdr_stream_remaining(xdr));
1294 return xdr->p != xdr->end;
1298 * xdr_init_decode - Initialize an xdr_stream for decoding data.
1299 * @xdr: pointer to xdr_stream struct
1300 * @buf: pointer to XDR buffer from which to decode data
1301 * @p: current pointer inside XDR buffer
1302 * @rqst: pointer to controlling rpc_rqst, for debugging
1304 void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
1305 struct rpc_rqst *rqst)
1308 xdr_reset_scratch_buffer(xdr);
1309 xdr->nwords = XDR_QUADLEN(buf->len);
1310 if (xdr_set_iov(xdr, buf->head, 0, buf->len) == 0 &&
1311 xdr_set_page_base(xdr, 0, buf->len) == 0)
1312 xdr_set_iov(xdr, buf->tail, 0, buf->len);
1313 if (p != NULL && p > xdr->p && xdr->end >= p) {
1314 xdr->nwords -= p - xdr->p;
1319 EXPORT_SYMBOL_GPL(xdr_init_decode);
1322 * xdr_init_decode_pages - Initialize an xdr_stream for decoding into pages
1323 * @xdr: pointer to xdr_stream struct
1324 * @buf: pointer to XDR buffer from which to decode data
1325 * @pages: list of pages to decode into
1326 * @len: length in bytes of buffer in pages
1328 void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
1329 struct page **pages, unsigned int len)
1331 memset(buf, 0, sizeof(*buf));
1333 buf->page_len = len;
1336 xdr_init_decode(xdr, buf, NULL, NULL);
1338 EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
1340 static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
1342 unsigned int nwords = XDR_QUADLEN(nbytes);
1344 __be32 *q = p + nwords;
1346 if (unlikely(nwords > xdr->nwords || q > xdr->end || q < p))
1349 xdr->nwords -= nwords;
1353 static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes)
1356 char *cpdest = xdr->scratch.iov_base;
1357 size_t cplen = (char *)xdr->end - (char *)xdr->p;
1359 if (nbytes > xdr->scratch.iov_len)
1361 p = __xdr_inline_decode(xdr, cplen);
1364 memcpy(cpdest, p, cplen);
1365 if (!xdr_set_next_buffer(xdr))
1369 p = __xdr_inline_decode(xdr, nbytes);
1372 memcpy(cpdest, p, nbytes);
1373 return xdr->scratch.iov_base;
1375 trace_rpc_xdr_overflow(xdr, nbytes);
1380 * xdr_inline_decode - Retrieve XDR data to decode
1381 * @xdr: pointer to xdr_stream struct
1382 * @nbytes: number of bytes of data to decode
1384 * Check if the input buffer is long enough to enable us to decode
1385 * 'nbytes' more bytes of data starting at the current position.
1386 * If so return the current pointer, then update the current
1389 __be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
1393 if (unlikely(nbytes == 0))
1395 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
1397 p = __xdr_inline_decode(xdr, nbytes);
1400 return xdr_copy_to_scratch(xdr, nbytes);
1402 trace_rpc_xdr_overflow(xdr, nbytes);
1405 EXPORT_SYMBOL_GPL(xdr_inline_decode);
1407 static void xdr_realign_pages(struct xdr_stream *xdr)
1409 struct xdr_buf *buf = xdr->buf;
1410 struct kvec *iov = buf->head;
1411 unsigned int cur = xdr_stream_pos(xdr);
1412 unsigned int copied;
1414 /* Realign pages to current pointer position */
1415 if (iov->iov_len > cur) {
1416 copied = xdr_shrink_bufhead(buf, cur);
1417 trace_rpc_xdr_alignment(xdr, cur, copied);
1418 xdr_set_page(xdr, 0, buf->page_len);
1422 static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len)
1424 struct xdr_buf *buf = xdr->buf;
1425 unsigned int nwords = XDR_QUADLEN(len);
1426 unsigned int copied;
1428 if (xdr->nwords == 0)
1431 xdr_realign_pages(xdr);
1432 if (nwords > xdr->nwords) {
1433 nwords = xdr->nwords;
1436 if (buf->page_len <= len)
1437 len = buf->page_len;
1438 else if (nwords < xdr->nwords) {
1439 /* Truncate page data and move it into the tail */
1440 copied = xdr_shrink_pagelen(buf, len);
1441 trace_rpc_xdr_alignment(xdr, len, copied);
1447 * xdr_read_pages - align page-based XDR data to current pointer position
1448 * @xdr: pointer to xdr_stream struct
1449 * @len: number of bytes of page data
1451 * Moves data beyond the current pointer position from the XDR head[] buffer
1452 * into the page list. Any data that lies beyond current position + @len
1453 * bytes is moved into the XDR tail[]. The xdr_stream current position is
1454 * then advanced past that data to align to the next XDR object in the tail.
1456 * Returns the number of XDR encoded bytes now contained in the pages
1458 unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
1460 unsigned int nwords = XDR_QUADLEN(len);
1461 unsigned int base, end, pglen;
1463 pglen = xdr_align_pages(xdr, nwords << 2);
1467 base = (nwords << 2) - pglen;
1468 end = xdr_stream_remaining(xdr) - pglen;
1470 xdr_set_tail_base(xdr, base, end);
1471 return len <= pglen ? len : pglen;
1473 EXPORT_SYMBOL_GPL(xdr_read_pages);
1475 unsigned int xdr_align_data(struct xdr_stream *xdr, unsigned int offset,
1476 unsigned int length)
1478 struct xdr_buf *buf = xdr->buf;
1479 unsigned int from, bytes, len;
1482 xdr_realign_pages(xdr);
1483 from = xdr_page_pos(xdr);
1485 if (from >= buf->page_len + buf->tail->iov_len)
1487 if (from + buf->head->iov_len >= buf->len)
1490 len = buf->len - buf->head->iov_len;
1492 /* We only shift data left! */
1493 if (WARN_ONCE(from < offset, "SUNRPC: misaligned data src=%u dst=%u\n",
1496 if (WARN_ONCE(offset > buf->page_len,
1497 "SUNRPC: buffer overflow. offset=%u, page_len=%u\n",
1498 offset, buf->page_len))
1501 /* Move page data to the left */
1502 shift = from - offset;
1503 xdr_buf_pages_shift_left(buf, from, len, shift);
1505 bytes = xdr_stream_remaining(xdr);
1510 xdr->buf->len -= shift;
1511 xdr_set_page(xdr, offset + length, bytes);
1514 EXPORT_SYMBOL_GPL(xdr_align_data);
1516 unsigned int xdr_expand_hole(struct xdr_stream *xdr, unsigned int offset,
1517 unsigned int length)
1519 struct xdr_buf *buf = xdr->buf;
1520 unsigned int from, to, shift;
1522 xdr_realign_pages(xdr);
1523 from = xdr_page_pos(xdr);
1524 to = xdr_align_size(offset + length);
1526 /* Could the hole be behind us? */
1528 unsigned int buflen = buf->len - buf->head->iov_len;
1530 xdr_buf_try_expand(buf, shift);
1531 xdr_buf_pages_shift_right(buf, from, buflen, shift);
1532 xdr_set_page(xdr, to, xdr_stream_remaining(xdr));
1533 } else if (to != from)
1534 xdr_align_data(xdr, to, 0);
1535 xdr_buf_pages_zero(buf, offset, length);
1539 EXPORT_SYMBOL_GPL(xdr_expand_hole);
1542 * xdr_enter_page - decode data from the XDR page
1543 * @xdr: pointer to xdr_stream struct
1544 * @len: number of bytes of page data
1546 * Moves data beyond the current pointer position from the XDR head[] buffer
1547 * into the page list. Any data that lies beyond current position + "len"
1548 * bytes is moved into the XDR tail[]. The current pointer is then
1549 * repositioned at the beginning of the first XDR page.
1551 void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
1553 len = xdr_align_pages(xdr, len);
1555 * Position current pointer at beginning of tail, and
1556 * set remaining message length.
1559 xdr_set_page_base(xdr, 0, len);
1561 EXPORT_SYMBOL_GPL(xdr_enter_page);
1563 static const struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0};
1565 void xdr_buf_from_iov(const struct kvec *iov, struct xdr_buf *buf)
1567 buf->head[0] = *iov;
1568 buf->tail[0] = empty_iov;
1570 buf->buflen = buf->len = iov->iov_len;
1572 EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
1575 * xdr_buf_subsegment - set subbuf to a portion of buf
1576 * @buf: an xdr buffer
1577 * @subbuf: the result buffer
1578 * @base: beginning of range in bytes
1579 * @len: length of range in bytes
1581 * sets @subbuf to an xdr buffer representing the portion of @buf of
1582 * length @len starting at offset @base.
1584 * @buf and @subbuf may be pointers to the same struct xdr_buf.
1586 * Returns -1 if base of length are out of bounds.
1588 int xdr_buf_subsegment(const struct xdr_buf *buf, struct xdr_buf *subbuf,
1589 unsigned int base, unsigned int len)
1591 subbuf->buflen = subbuf->len = len;
1592 if (base < buf->head[0].iov_len) {
1593 subbuf->head[0].iov_base = buf->head[0].iov_base + base;
1594 subbuf->head[0].iov_len = min_t(unsigned int, len,
1595 buf->head[0].iov_len - base);
1596 len -= subbuf->head[0].iov_len;
1599 base -= buf->head[0].iov_len;
1600 subbuf->head[0].iov_base = buf->head[0].iov_base;
1601 subbuf->head[0].iov_len = 0;
1604 if (base < buf->page_len) {
1605 subbuf->page_len = min(buf->page_len - base, len);
1606 base += buf->page_base;
1607 subbuf->page_base = base & ~PAGE_MASK;
1608 subbuf->pages = &buf->pages[base >> PAGE_SHIFT];
1609 len -= subbuf->page_len;
1612 base -= buf->page_len;
1613 subbuf->pages = buf->pages;
1614 subbuf->page_base = 0;
1615 subbuf->page_len = 0;
1618 if (base < buf->tail[0].iov_len) {
1619 subbuf->tail[0].iov_base = buf->tail[0].iov_base + base;
1620 subbuf->tail[0].iov_len = min_t(unsigned int, len,
1621 buf->tail[0].iov_len - base);
1622 len -= subbuf->tail[0].iov_len;
1625 base -= buf->tail[0].iov_len;
1626 subbuf->tail[0].iov_base = buf->tail[0].iov_base;
1627 subbuf->tail[0].iov_len = 0;
1634 EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
1637 * xdr_stream_subsegment - set @subbuf to a portion of @xdr
1638 * @xdr: an xdr_stream set up for decoding
1639 * @subbuf: the result buffer
1640 * @nbytes: length of @xdr to extract, in bytes
1642 * Sets up @subbuf to represent a portion of @xdr. The portion
1643 * starts at the current offset in @xdr, and extends for a length
1644 * of @nbytes. If this is successful, @xdr is advanced to the next
1645 * XDR data item following that portion.
1648 * %true: @subbuf has been initialized, and @xdr has been advanced.
1649 * %false: a bounds error has occurred
1651 bool xdr_stream_subsegment(struct xdr_stream *xdr, struct xdr_buf *subbuf,
1652 unsigned int nbytes)
1654 unsigned int start = xdr_stream_pos(xdr);
1655 unsigned int remaining, len;
1657 /* Extract @subbuf and bounds-check the fn arguments */
1658 if (xdr_buf_subsegment(xdr->buf, subbuf, start, nbytes))
1661 /* Advance @xdr by @nbytes */
1662 for (remaining = nbytes; remaining;) {
1663 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
1666 len = (char *)xdr->end - (char *)xdr->p;
1667 if (remaining <= len) {
1668 xdr->p = (__be32 *)((char *)xdr->p +
1669 (remaining + xdr_pad_size(nbytes)));
1673 xdr->p = (__be32 *)((char *)xdr->p + len);
1678 xdr_stream_set_pos(xdr, start + nbytes);
1681 EXPORT_SYMBOL_GPL(xdr_stream_subsegment);
1684 * xdr_buf_trim - lop at most "len" bytes off the end of "buf"
1685 * @buf: buf to be trimmed
1686 * @len: number of bytes to reduce "buf" by
1688 * Trim an xdr_buf by the given number of bytes by fixing up the lengths. Note
1689 * that it's possible that we'll trim less than that amount if the xdr_buf is
1690 * too small, or if (for instance) it's all in the head and the parser has
1691 * already read too far into it.
1693 void xdr_buf_trim(struct xdr_buf *buf, unsigned int len)
1696 unsigned int trim = len;
1698 if (buf->tail[0].iov_len) {
1699 cur = min_t(size_t, buf->tail[0].iov_len, trim);
1700 buf->tail[0].iov_len -= cur;
1706 if (buf->page_len) {
1707 cur = min_t(unsigned int, buf->page_len, trim);
1708 buf->page_len -= cur;
1714 if (buf->head[0].iov_len) {
1715 cur = min_t(size_t, buf->head[0].iov_len, trim);
1716 buf->head[0].iov_len -= cur;
1720 buf->len -= (len - trim);
1722 EXPORT_SYMBOL_GPL(xdr_buf_trim);
1724 static void __read_bytes_from_xdr_buf(const struct xdr_buf *subbuf,
1725 void *obj, unsigned int len)
1727 unsigned int this_len;
1729 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1730 memcpy(obj, subbuf->head[0].iov_base, this_len);
1733 this_len = min_t(unsigned int, len, subbuf->page_len);
1734 _copy_from_pages(obj, subbuf->pages, subbuf->page_base, this_len);
1737 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1738 memcpy(obj, subbuf->tail[0].iov_base, this_len);
1741 /* obj is assumed to point to allocated memory of size at least len: */
1742 int read_bytes_from_xdr_buf(const struct xdr_buf *buf, unsigned int base,
1743 void *obj, unsigned int len)
1745 struct xdr_buf subbuf;
1748 status = xdr_buf_subsegment(buf, &subbuf, base, len);
1751 __read_bytes_from_xdr_buf(&subbuf, obj, len);
1754 EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf);
1756 static void __write_bytes_to_xdr_buf(const struct xdr_buf *subbuf,
1757 void *obj, unsigned int len)
1759 unsigned int this_len;
1761 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1762 memcpy(subbuf->head[0].iov_base, obj, this_len);
1765 this_len = min_t(unsigned int, len, subbuf->page_len);
1766 _copy_to_pages(subbuf->pages, subbuf->page_base, obj, this_len);
1769 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1770 memcpy(subbuf->tail[0].iov_base, obj, this_len);
1773 /* obj is assumed to point to allocated memory of size at least len: */
1774 int write_bytes_to_xdr_buf(const struct xdr_buf *buf, unsigned int base,
1775 void *obj, unsigned int len)
1777 struct xdr_buf subbuf;
1780 status = xdr_buf_subsegment(buf, &subbuf, base, len);
1783 __write_bytes_to_xdr_buf(&subbuf, obj, len);
1786 EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf);
1788 int xdr_decode_word(const struct xdr_buf *buf, unsigned int base, u32 *obj)
1793 status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
1796 *obj = be32_to_cpu(raw);
1799 EXPORT_SYMBOL_GPL(xdr_decode_word);
1801 int xdr_encode_word(const struct xdr_buf *buf, unsigned int base, u32 obj)
1803 __be32 raw = cpu_to_be32(obj);
1805 return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj));
1807 EXPORT_SYMBOL_GPL(xdr_encode_word);
1809 /* Returns 0 on success, or else a negative error code. */
1810 static int xdr_xcode_array2(const struct xdr_buf *buf, unsigned int base,
1811 struct xdr_array2_desc *desc, int encode)
1813 char *elem = NULL, *c;
1814 unsigned int copied = 0, todo, avail_here;
1815 struct page **ppages = NULL;
1819 if (xdr_encode_word(buf, base, desc->array_len) != 0)
1822 if (xdr_decode_word(buf, base, &desc->array_len) != 0 ||
1823 desc->array_len > desc->array_maxlen ||
1824 (unsigned long) base + 4 + desc->array_len *
1825 desc->elem_size > buf->len)
1833 todo = desc->array_len * desc->elem_size;
1836 if (todo && base < buf->head->iov_len) {
1837 c = buf->head->iov_base + base;
1838 avail_here = min_t(unsigned int, todo,
1839 buf->head->iov_len - base);
1842 while (avail_here >= desc->elem_size) {
1843 err = desc->xcode(desc, c);
1846 c += desc->elem_size;
1847 avail_here -= desc->elem_size;
1851 elem = kmalloc(desc->elem_size, GFP_KERNEL);
1857 err = desc->xcode(desc, elem);
1860 memcpy(c, elem, avail_here);
1862 memcpy(elem, c, avail_here);
1863 copied = avail_here;
1865 base = buf->head->iov_len; /* align to start of pages */
1868 /* process pages array */
1869 base -= buf->head->iov_len;
1870 if (todo && base < buf->page_len) {
1871 unsigned int avail_page;
1873 avail_here = min(todo, buf->page_len - base);
1876 base += buf->page_base;
1877 ppages = buf->pages + (base >> PAGE_SHIFT);
1879 avail_page = min_t(unsigned int, PAGE_SIZE - base,
1881 c = kmap(*ppages) + base;
1883 while (avail_here) {
1884 avail_here -= avail_page;
1885 if (copied || avail_page < desc->elem_size) {
1886 unsigned int l = min(avail_page,
1887 desc->elem_size - copied);
1889 elem = kmalloc(desc->elem_size,
1897 err = desc->xcode(desc, elem);
1901 memcpy(c, elem + copied, l);
1903 if (copied == desc->elem_size)
1906 memcpy(elem + copied, c, l);
1908 if (copied == desc->elem_size) {
1909 err = desc->xcode(desc, elem);
1918 while (avail_page >= desc->elem_size) {
1919 err = desc->xcode(desc, c);
1922 c += desc->elem_size;
1923 avail_page -= desc->elem_size;
1926 unsigned int l = min(avail_page,
1927 desc->elem_size - copied);
1929 elem = kmalloc(desc->elem_size,
1937 err = desc->xcode(desc, elem);
1941 memcpy(c, elem + copied, l);
1943 if (copied == desc->elem_size)
1946 memcpy(elem + copied, c, l);
1948 if (copied == desc->elem_size) {
1949 err = desc->xcode(desc, elem);
1962 avail_page = min(avail_here,
1963 (unsigned int) PAGE_SIZE);
1965 base = buf->page_len; /* align to start of tail */
1969 base -= buf->page_len;
1971 c = buf->tail->iov_base + base;
1973 unsigned int l = desc->elem_size - copied;
1976 memcpy(c, elem + copied, l);
1978 memcpy(elem + copied, c, l);
1979 err = desc->xcode(desc, elem);
1987 err = desc->xcode(desc, c);
1990 c += desc->elem_size;
1991 todo -= desc->elem_size;
2003 int xdr_decode_array2(const struct xdr_buf *buf, unsigned int base,
2004 struct xdr_array2_desc *desc)
2006 if (base >= buf->len)
2009 return xdr_xcode_array2(buf, base, desc, 0);
2011 EXPORT_SYMBOL_GPL(xdr_decode_array2);
2013 int xdr_encode_array2(const struct xdr_buf *buf, unsigned int base,
2014 struct xdr_array2_desc *desc)
2016 if ((unsigned long) base + 4 + desc->array_len * desc->elem_size >
2017 buf->head->iov_len + buf->page_len + buf->tail->iov_len)
2020 return xdr_xcode_array2(buf, base, desc, 1);
2022 EXPORT_SYMBOL_GPL(xdr_encode_array2);
2024 int xdr_process_buf(const struct xdr_buf *buf, unsigned int offset,
2026 int (*actor)(struct scatterlist *, void *), void *data)
2029 unsigned int page_len, thislen, page_offset;
2030 struct scatterlist sg[1];
2032 sg_init_table(sg, 1);
2034 if (offset >= buf->head[0].iov_len) {
2035 offset -= buf->head[0].iov_len;
2037 thislen = buf->head[0].iov_len - offset;
2040 sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
2041 ret = actor(sg, data);
2050 if (offset >= buf->page_len) {
2051 offset -= buf->page_len;
2053 page_len = buf->page_len - offset;
2057 page_offset = (offset + buf->page_base) & (PAGE_SIZE - 1);
2058 i = (offset + buf->page_base) >> PAGE_SHIFT;
2059 thislen = PAGE_SIZE - page_offset;
2061 if (thislen > page_len)
2063 sg_set_page(sg, buf->pages[i], thislen, page_offset);
2064 ret = actor(sg, data);
2067 page_len -= thislen;
2070 thislen = PAGE_SIZE;
2071 } while (page_len != 0);
2076 if (offset < buf->tail[0].iov_len) {
2077 thislen = buf->tail[0].iov_len - offset;
2080 sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
2081 ret = actor(sg, data);
2089 EXPORT_SYMBOL_GPL(xdr_process_buf);
2092 * xdr_stream_decode_opaque - Decode variable length opaque
2093 * @xdr: pointer to xdr_stream
2094 * @ptr: location to store opaque data
2095 * @size: size of storage buffer @ptr
2098 * On success, returns size of object stored in *@ptr
2099 * %-EBADMSG on XDR buffer overflow
2100 * %-EMSGSIZE on overflow of storage buffer @ptr
2102 ssize_t xdr_stream_decode_opaque(struct xdr_stream *xdr, void *ptr, size_t size)
2107 ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
2110 memcpy(ptr, p, ret);
2113 EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque);
2116 * xdr_stream_decode_opaque_dup - Decode and duplicate variable length opaque
2117 * @xdr: pointer to xdr_stream
2118 * @ptr: location to store pointer to opaque data
2119 * @maxlen: maximum acceptable object size
2120 * @gfp_flags: GFP mask to use
2123 * On success, returns size of object stored in *@ptr
2124 * %-EBADMSG on XDR buffer overflow
2125 * %-EMSGSIZE if the size of the object would exceed @maxlen
2126 * %-ENOMEM on memory allocation failure
2128 ssize_t xdr_stream_decode_opaque_dup(struct xdr_stream *xdr, void **ptr,
2129 size_t maxlen, gfp_t gfp_flags)
2134 ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
2136 *ptr = kmemdup(p, ret, gfp_flags);
2144 EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque_dup);
2147 * xdr_stream_decode_string - Decode variable length string
2148 * @xdr: pointer to xdr_stream
2149 * @str: location to store string
2150 * @size: size of storage buffer @str
2153 * On success, returns length of NUL-terminated string stored in *@str
2154 * %-EBADMSG on XDR buffer overflow
2155 * %-EMSGSIZE on overflow of storage buffer @str
2157 ssize_t xdr_stream_decode_string(struct xdr_stream *xdr, char *str, size_t size)
2162 ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
2164 memcpy(str, p, ret);
2171 EXPORT_SYMBOL_GPL(xdr_stream_decode_string);
2174 * xdr_stream_decode_string_dup - Decode and duplicate variable length string
2175 * @xdr: pointer to xdr_stream
2176 * @str: location to store pointer to string
2177 * @maxlen: maximum acceptable string length
2178 * @gfp_flags: GFP mask to use
2181 * On success, returns length of NUL-terminated string stored in *@ptr
2182 * %-EBADMSG on XDR buffer overflow
2183 * %-EMSGSIZE if the size of the string would exceed @maxlen
2184 * %-ENOMEM on memory allocation failure
2186 ssize_t xdr_stream_decode_string_dup(struct xdr_stream *xdr, char **str,
2187 size_t maxlen, gfp_t gfp_flags)
2192 ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
2194 char *s = kmemdup_nul(p, ret, gfp_flags);
2204 EXPORT_SYMBOL_GPL(xdr_stream_decode_string_dup);