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);
778 static void xdr_buf_head_shift_left(const struct xdr_buf *buf,
779 unsigned int base, unsigned int len,
782 const struct kvec *head = buf->head;
789 bytes = (shift - base);
796 if (base < head->iov_len) {
797 bytes = min_t(unsigned int, len, head->iov_len - base);
798 memmove(head->iov_base + (base - shift),
799 head->iov_base + base, bytes);
803 xdr_buf_pages_shift_left(buf, base - head->iov_len, len, shift);
809 * @len: new length of buf->head[0]
811 * Shrinks XDR buffer's header kvec buf->head[0], setting it to
812 * 'len' bytes. The extra data is not lost, but is instead
813 * moved into the inlined pages and/or the tail.
815 static unsigned int xdr_shrink_bufhead(struct xdr_buf *buf, unsigned int len)
817 struct kvec *head = buf->head;
818 unsigned int shift, buflen = max(buf->len, len);
820 WARN_ON_ONCE(len > head->iov_len);
821 if (head->iov_len > buflen) {
822 buf->buflen -= head->iov_len - buflen;
823 head->iov_len = buflen;
825 if (len >= head->iov_len)
827 shift = head->iov_len - len;
828 xdr_buf_try_expand(buf, shift);
829 xdr_buf_head_shift_right(buf, len, buflen - len, shift);
831 buf->buflen -= shift;
837 * xdr_shrink_pagelen - shrinks buf->pages to @len bytes
839 * @len: new page buffer length
841 * The extra data is not lost, but is instead moved into buf->tail.
842 * Returns the actual number of bytes moved.
844 static unsigned int xdr_shrink_pagelen(struct xdr_buf *buf, unsigned int len)
846 unsigned int shift, buflen = buf->len - buf->head->iov_len;
848 WARN_ON_ONCE(len > buf->page_len);
849 if (buf->head->iov_len >= buf->len || len > buflen)
851 if (buf->page_len > buflen) {
852 buf->buflen -= buf->page_len - buflen;
853 buf->page_len = buflen;
855 if (len >= buf->page_len)
857 shift = buf->page_len - len;
858 xdr_buf_try_expand(buf, shift);
859 xdr_buf_pages_shift_right(buf, len, buflen - len, shift);
862 buf->buflen -= shift;
867 xdr_shift_buf(struct xdr_buf *buf, size_t len)
869 xdr_shrink_bufhead(buf, buf->head->iov_len - len);
871 EXPORT_SYMBOL_GPL(xdr_shift_buf);
874 * xdr_stream_pos - Return the current offset from the start of the xdr_stream
875 * @xdr: pointer to struct xdr_stream
877 unsigned int xdr_stream_pos(const struct xdr_stream *xdr)
879 return (unsigned int)(XDR_QUADLEN(xdr->buf->len) - xdr->nwords) << 2;
881 EXPORT_SYMBOL_GPL(xdr_stream_pos);
883 static void xdr_stream_set_pos(struct xdr_stream *xdr, unsigned int pos)
885 unsigned int blen = xdr->buf->len;
887 xdr->nwords = blen > pos ? XDR_QUADLEN(blen) - XDR_QUADLEN(pos) : 0;
890 static void xdr_stream_page_set_pos(struct xdr_stream *xdr, unsigned int pos)
892 xdr_stream_set_pos(xdr, pos + xdr->buf->head[0].iov_len);
896 * xdr_page_pos - Return the current offset from the start of the xdr pages
897 * @xdr: pointer to struct xdr_stream
899 unsigned int xdr_page_pos(const struct xdr_stream *xdr)
901 unsigned int pos = xdr_stream_pos(xdr);
903 WARN_ON(pos < xdr->buf->head[0].iov_len);
904 return pos - xdr->buf->head[0].iov_len;
906 EXPORT_SYMBOL_GPL(xdr_page_pos);
909 * xdr_init_encode - Initialize a struct xdr_stream for sending data.
910 * @xdr: pointer to xdr_stream struct
911 * @buf: pointer to XDR buffer in which to encode data
912 * @p: current pointer inside XDR buffer
913 * @rqst: pointer to controlling rpc_rqst, for debugging
915 * Note: at the moment the RPC client only passes the length of our
916 * scratch buffer in the xdr_buf's header kvec. Previously this
917 * meant we needed to call xdr_adjust_iovec() after encoding the
918 * data. With the new scheme, the xdr_stream manages the details
919 * of the buffer length, and takes care of adjusting the kvec
922 void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
923 struct rpc_rqst *rqst)
925 struct kvec *iov = buf->head;
926 int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len;
928 xdr_reset_scratch_buffer(xdr);
929 BUG_ON(scratch_len < 0);
932 xdr->p = (__be32 *)((char *)iov->iov_base + iov->iov_len);
933 xdr->end = (__be32 *)((char *)iov->iov_base + scratch_len);
934 BUG_ON(iov->iov_len > scratch_len);
936 if (p != xdr->p && p != NULL) {
939 BUG_ON(p < xdr->p || p > xdr->end);
940 len = (char *)p - (char *)xdr->p;
947 EXPORT_SYMBOL_GPL(xdr_init_encode);
950 * __xdr_commit_encode - Ensure all data is written to buffer
951 * @xdr: pointer to xdr_stream
953 * We handle encoding across page boundaries by giving the caller a
954 * temporary location to write to, then later copying the data into
955 * place; xdr_commit_encode does that copying.
957 * Normally the caller doesn't need to call this directly, as the
958 * following xdr_reserve_space will do it. But an explicit call may be
959 * required at the end of encoding, or any other time when the xdr_buf
960 * data might be read.
962 void __xdr_commit_encode(struct xdr_stream *xdr)
964 size_t shift = xdr->scratch.iov_len;
967 page = page_address(*xdr->page_ptr);
968 memcpy(xdr->scratch.iov_base, page, shift);
969 memmove(page, page + shift, (void *)xdr->p - page);
970 xdr_reset_scratch_buffer(xdr);
972 EXPORT_SYMBOL_GPL(__xdr_commit_encode);
975 * The buffer space to be reserved crosses the boundary between
976 * xdr->buf->head and xdr->buf->pages, or between two pages
977 * in xdr->buf->pages.
979 static noinline __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr,
983 int frag1bytes, frag2bytes;
986 if (nbytes > PAGE_SIZE)
987 goto out_overflow; /* Bigger buffers require special handling */
988 if (xdr->buf->len + nbytes > xdr->buf->buflen)
989 goto out_overflow; /* Sorry, we're totally out of space */
990 frag1bytes = (xdr->end - xdr->p) << 2;
991 frag2bytes = nbytes - frag1bytes;
993 xdr->iov->iov_len += frag1bytes;
995 xdr->buf->page_len += frag1bytes;
1000 * If the last encode didn't end exactly on a page boundary, the
1001 * next one will straddle boundaries. Encode into the next
1002 * page, then copy it back later in xdr_commit_encode. We use
1003 * the "scratch" iov to track any temporarily unused fragment of
1004 * space at the end of the previous buffer:
1006 xdr_set_scratch_buffer(xdr, xdr->p, frag1bytes);
1009 * xdr->p is where the next encode will start after
1010 * xdr_commit_encode() has shifted this one back:
1012 p = page_address(*xdr->page_ptr);
1013 xdr->p = p + frag2bytes;
1014 space_left = xdr->buf->buflen - xdr->buf->len;
1015 if (space_left - frag1bytes >= PAGE_SIZE)
1016 xdr->end = p + PAGE_SIZE;
1018 xdr->end = p + space_left - frag1bytes;
1020 xdr->buf->page_len += frag2bytes;
1021 xdr->buf->len += nbytes;
1024 trace_rpc_xdr_overflow(xdr, nbytes);
1029 * xdr_reserve_space - Reserve buffer space for sending
1030 * @xdr: pointer to xdr_stream
1031 * @nbytes: number of bytes to reserve
1033 * Checks that we have enough buffer space to encode 'nbytes' more
1034 * bytes of data. If so, update the total xdr_buf length, and
1035 * adjust the length of the current kvec.
1037 __be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
1042 xdr_commit_encode(xdr);
1043 /* align nbytes on the next 32-bit boundary */
1046 q = p + (nbytes >> 2);
1047 if (unlikely(q > xdr->end || q < p))
1048 return xdr_get_next_encode_buffer(xdr, nbytes);
1051 xdr->iov->iov_len += nbytes;
1053 xdr->buf->page_len += nbytes;
1054 xdr->buf->len += nbytes;
1057 EXPORT_SYMBOL_GPL(xdr_reserve_space);
1061 * xdr_reserve_space_vec - Reserves a large amount of buffer space for sending
1062 * @xdr: pointer to xdr_stream
1063 * @vec: pointer to a kvec array
1064 * @nbytes: number of bytes to reserve
1066 * Reserves enough buffer space to encode 'nbytes' of data and stores the
1067 * pointers in 'vec'. The size argument passed to xdr_reserve_space() is
1068 * determined based on the number of bytes remaining in the current page to
1069 * avoid invalidating iov_base pointers when xdr_commit_encode() is called.
1071 int xdr_reserve_space_vec(struct xdr_stream *xdr, struct kvec *vec, size_t nbytes)
1078 * svcrdma requires every READ payload to start somewhere
1081 if (xdr->iov == xdr->buf->head) {
1087 thislen = xdr->buf->page_len % PAGE_SIZE;
1088 thislen = min_t(size_t, nbytes, PAGE_SIZE - thislen);
1090 p = xdr_reserve_space(xdr, thislen);
1094 vec[v].iov_base = p;
1095 vec[v].iov_len = thislen;
1102 EXPORT_SYMBOL_GPL(xdr_reserve_space_vec);
1105 * xdr_truncate_encode - truncate an encode buffer
1106 * @xdr: pointer to xdr_stream
1107 * @len: new length of buffer
1109 * Truncates the xdr stream, so that xdr->buf->len == len,
1110 * and xdr->p points at offset len from the start of the buffer, and
1111 * head, tail, and page lengths are adjusted to correspond.
1113 * If this means moving xdr->p to a different buffer, we assume that
1114 * the end pointer should be set to the end of the current page,
1115 * except in the case of the head buffer when we assume the head
1116 * buffer's current length represents the end of the available buffer.
1118 * This is *not* safe to use on a buffer that already has inlined page
1119 * cache pages (as in a zero-copy server read reply), except for the
1120 * simple case of truncating from one position in the tail to another.
1123 void xdr_truncate_encode(struct xdr_stream *xdr, size_t len)
1125 struct xdr_buf *buf = xdr->buf;
1126 struct kvec *head = buf->head;
1127 struct kvec *tail = buf->tail;
1131 if (len > buf->len) {
1135 xdr_commit_encode(xdr);
1137 fraglen = min_t(int, buf->len - len, tail->iov_len);
1138 tail->iov_len -= fraglen;
1139 buf->len -= fraglen;
1140 if (tail->iov_len) {
1141 xdr->p = tail->iov_base + tail->iov_len;
1142 WARN_ON_ONCE(!xdr->end);
1143 WARN_ON_ONCE(!xdr->iov);
1146 WARN_ON_ONCE(fraglen);
1147 fraglen = min_t(int, buf->len - len, buf->page_len);
1148 buf->page_len -= fraglen;
1149 buf->len -= fraglen;
1151 new = buf->page_base + buf->page_len;
1153 xdr->page_ptr = buf->pages + (new >> PAGE_SHIFT);
1155 if (buf->page_len) {
1156 xdr->p = page_address(*xdr->page_ptr);
1157 xdr->end = (void *)xdr->p + PAGE_SIZE;
1158 xdr->p = (void *)xdr->p + (new % PAGE_SIZE);
1159 WARN_ON_ONCE(xdr->iov);
1163 xdr->end = head->iov_base + head->iov_len;
1164 /* (otherwise assume xdr->end is already set) */
1166 head->iov_len = len;
1168 xdr->p = head->iov_base + head->iov_len;
1169 xdr->iov = buf->head;
1171 EXPORT_SYMBOL(xdr_truncate_encode);
1174 * xdr_restrict_buflen - decrease available buffer space
1175 * @xdr: pointer to xdr_stream
1176 * @newbuflen: new maximum number of bytes available
1178 * Adjust our idea of how much space is available in the buffer.
1179 * If we've already used too much space in the buffer, returns -1.
1180 * If the available space is already smaller than newbuflen, returns 0
1181 * and does nothing. Otherwise, adjusts xdr->buf->buflen to newbuflen
1182 * and ensures xdr->end is set at most offset newbuflen from the start
1185 int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen)
1187 struct xdr_buf *buf = xdr->buf;
1188 int left_in_this_buf = (void *)xdr->end - (void *)xdr->p;
1189 int end_offset = buf->len + left_in_this_buf;
1191 if (newbuflen < 0 || newbuflen < buf->len)
1193 if (newbuflen > buf->buflen)
1195 if (newbuflen < end_offset)
1196 xdr->end = (void *)xdr->end + newbuflen - end_offset;
1197 buf->buflen = newbuflen;
1200 EXPORT_SYMBOL(xdr_restrict_buflen);
1203 * xdr_write_pages - Insert a list of pages into an XDR buffer for sending
1204 * @xdr: pointer to xdr_stream
1205 * @pages: list of pages
1206 * @base: offset of first byte
1207 * @len: length of data in bytes
1210 void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base,
1213 struct xdr_buf *buf = xdr->buf;
1214 struct kvec *iov = buf->tail;
1216 buf->page_base = base;
1217 buf->page_len = len;
1219 iov->iov_base = (char *)xdr->p;
1224 unsigned int pad = 4 - (len & 3);
1226 BUG_ON(xdr->p >= xdr->end);
1227 iov->iov_base = (char *)xdr->p + (len & 3);
1228 iov->iov_len += pad;
1235 EXPORT_SYMBOL_GPL(xdr_write_pages);
1237 static unsigned int xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
1238 unsigned int base, unsigned int len)
1240 if (len > iov->iov_len)
1242 if (unlikely(base > len))
1244 xdr->p = (__be32*)(iov->iov_base + base);
1245 xdr->end = (__be32*)(iov->iov_base + len);
1247 xdr->page_ptr = NULL;
1251 static unsigned int xdr_set_tail_base(struct xdr_stream *xdr,
1252 unsigned int base, unsigned int len)
1254 struct xdr_buf *buf = xdr->buf;
1256 xdr_stream_set_pos(xdr, base + buf->page_len + buf->head->iov_len);
1257 return xdr_set_iov(xdr, buf->tail, base, len);
1260 static unsigned int xdr_set_page_base(struct xdr_stream *xdr,
1261 unsigned int base, unsigned int len)
1264 unsigned int maxlen;
1269 maxlen = xdr->buf->page_len;
1277 xdr_stream_page_set_pos(xdr, base);
1278 base += xdr->buf->page_base;
1280 pgnr = base >> PAGE_SHIFT;
1281 xdr->page_ptr = &xdr->buf->pages[pgnr];
1282 kaddr = page_address(*xdr->page_ptr);
1284 pgoff = base & ~PAGE_MASK;
1285 xdr->p = (__be32*)(kaddr + pgoff);
1287 pgend = pgoff + len;
1288 if (pgend > PAGE_SIZE)
1290 xdr->end = (__be32*)(kaddr + pgend);
1295 static void xdr_set_page(struct xdr_stream *xdr, unsigned int base,
1298 if (xdr_set_page_base(xdr, base, len) == 0) {
1299 base -= xdr->buf->page_len;
1300 xdr_set_tail_base(xdr, base, len);
1304 static void xdr_set_next_page(struct xdr_stream *xdr)
1306 unsigned int newbase;
1308 newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT;
1309 newbase -= xdr->buf->page_base;
1310 if (newbase < xdr->buf->page_len)
1311 xdr_set_page_base(xdr, newbase, xdr_stream_remaining(xdr));
1313 xdr_set_tail_base(xdr, 0, xdr_stream_remaining(xdr));
1316 static bool xdr_set_next_buffer(struct xdr_stream *xdr)
1318 if (xdr->page_ptr != NULL)
1319 xdr_set_next_page(xdr);
1320 else if (xdr->iov == xdr->buf->head)
1321 xdr_set_page(xdr, 0, xdr_stream_remaining(xdr));
1322 return xdr->p != xdr->end;
1326 * xdr_init_decode - Initialize an xdr_stream for decoding data.
1327 * @xdr: pointer to xdr_stream struct
1328 * @buf: pointer to XDR buffer from which to decode data
1329 * @p: current pointer inside XDR buffer
1330 * @rqst: pointer to controlling rpc_rqst, for debugging
1332 void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
1333 struct rpc_rqst *rqst)
1336 xdr_reset_scratch_buffer(xdr);
1337 xdr->nwords = XDR_QUADLEN(buf->len);
1338 if (xdr_set_iov(xdr, buf->head, 0, buf->len) == 0 &&
1339 xdr_set_page_base(xdr, 0, buf->len) == 0)
1340 xdr_set_iov(xdr, buf->tail, 0, buf->len);
1341 if (p != NULL && p > xdr->p && xdr->end >= p) {
1342 xdr->nwords -= p - xdr->p;
1347 EXPORT_SYMBOL_GPL(xdr_init_decode);
1350 * xdr_init_decode_pages - Initialize an xdr_stream for decoding into pages
1351 * @xdr: pointer to xdr_stream struct
1352 * @buf: pointer to XDR buffer from which to decode data
1353 * @pages: list of pages to decode into
1354 * @len: length in bytes of buffer in pages
1356 void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
1357 struct page **pages, unsigned int len)
1359 memset(buf, 0, sizeof(*buf));
1361 buf->page_len = len;
1364 xdr_init_decode(xdr, buf, NULL, NULL);
1366 EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
1368 static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
1370 unsigned int nwords = XDR_QUADLEN(nbytes);
1372 __be32 *q = p + nwords;
1374 if (unlikely(nwords > xdr->nwords || q > xdr->end || q < p))
1377 xdr->nwords -= nwords;
1381 static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes)
1384 char *cpdest = xdr->scratch.iov_base;
1385 size_t cplen = (char *)xdr->end - (char *)xdr->p;
1387 if (nbytes > xdr->scratch.iov_len)
1389 p = __xdr_inline_decode(xdr, cplen);
1392 memcpy(cpdest, p, cplen);
1393 if (!xdr_set_next_buffer(xdr))
1397 p = __xdr_inline_decode(xdr, nbytes);
1400 memcpy(cpdest, p, nbytes);
1401 return xdr->scratch.iov_base;
1403 trace_rpc_xdr_overflow(xdr, nbytes);
1408 * xdr_inline_decode - Retrieve XDR data to decode
1409 * @xdr: pointer to xdr_stream struct
1410 * @nbytes: number of bytes of data to decode
1412 * Check if the input buffer is long enough to enable us to decode
1413 * 'nbytes' more bytes of data starting at the current position.
1414 * If so return the current pointer, then update the current
1417 __be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
1421 if (unlikely(nbytes == 0))
1423 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
1425 p = __xdr_inline_decode(xdr, nbytes);
1428 return xdr_copy_to_scratch(xdr, nbytes);
1430 trace_rpc_xdr_overflow(xdr, nbytes);
1433 EXPORT_SYMBOL_GPL(xdr_inline_decode);
1435 static void xdr_realign_pages(struct xdr_stream *xdr)
1437 struct xdr_buf *buf = xdr->buf;
1438 struct kvec *iov = buf->head;
1439 unsigned int cur = xdr_stream_pos(xdr);
1440 unsigned int copied;
1442 /* Realign pages to current pointer position */
1443 if (iov->iov_len > cur) {
1444 copied = xdr_shrink_bufhead(buf, cur);
1445 trace_rpc_xdr_alignment(xdr, cur, copied);
1446 xdr_set_page(xdr, 0, buf->page_len);
1450 static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len)
1452 struct xdr_buf *buf = xdr->buf;
1453 unsigned int nwords = XDR_QUADLEN(len);
1454 unsigned int copied;
1456 if (xdr->nwords == 0)
1459 xdr_realign_pages(xdr);
1460 if (nwords > xdr->nwords) {
1461 nwords = xdr->nwords;
1464 if (buf->page_len <= len)
1465 len = buf->page_len;
1466 else if (nwords < xdr->nwords) {
1467 /* Truncate page data and move it into the tail */
1468 copied = xdr_shrink_pagelen(buf, len);
1469 trace_rpc_xdr_alignment(xdr, len, copied);
1475 * xdr_read_pages - align page-based XDR data to current pointer position
1476 * @xdr: pointer to xdr_stream struct
1477 * @len: number of bytes of page data
1479 * Moves data beyond the current pointer position from the XDR head[] buffer
1480 * into the page list. Any data that lies beyond current position + @len
1481 * bytes is moved into the XDR tail[]. The xdr_stream current position is
1482 * then advanced past that data to align to the next XDR object in the tail.
1484 * Returns the number of XDR encoded bytes now contained in the pages
1486 unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
1488 unsigned int nwords = XDR_QUADLEN(len);
1489 unsigned int base, end, pglen;
1491 pglen = xdr_align_pages(xdr, nwords << 2);
1495 base = (nwords << 2) - pglen;
1496 end = xdr_stream_remaining(xdr) - pglen;
1498 xdr_set_tail_base(xdr, base, end);
1499 return len <= pglen ? len : pglen;
1501 EXPORT_SYMBOL_GPL(xdr_read_pages);
1504 * xdr_set_pagelen - Sets the length of the XDR pages
1505 * @xdr: pointer to xdr_stream struct
1506 * @len: new length of the XDR page data
1508 * Either grows or shrinks the length of the xdr pages by setting pagelen to
1509 * @len bytes. When shrinking, any extra data is moved into buf->tail, whereas
1510 * when growing any data beyond the current pointer is moved into the tail.
1512 * Returns True if the operation was successful, and False otherwise.
1514 void xdr_set_pagelen(struct xdr_stream *xdr, unsigned int len)
1516 struct xdr_buf *buf = xdr->buf;
1517 size_t remaining = xdr_stream_remaining(xdr);
1520 if (len < buf->page_len) {
1521 base = buf->page_len - len;
1522 xdr_shrink_pagelen(buf, len);
1524 xdr_buf_head_shift_right(buf, xdr_stream_pos(xdr),
1525 buf->page_len, remaining);
1526 if (len > buf->page_len)
1527 xdr_buf_try_expand(buf, len - buf->page_len);
1529 xdr_set_tail_base(xdr, base, remaining);
1531 EXPORT_SYMBOL_GPL(xdr_set_pagelen);
1534 * xdr_enter_page - decode data from the XDR page
1535 * @xdr: pointer to xdr_stream struct
1536 * @len: number of bytes of page data
1538 * Moves data beyond the current pointer position from the XDR head[] buffer
1539 * into the page list. Any data that lies beyond current position + "len"
1540 * bytes is moved into the XDR tail[]. The current pointer is then
1541 * repositioned at the beginning of the first XDR page.
1543 void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
1545 len = xdr_align_pages(xdr, len);
1547 * Position current pointer at beginning of tail, and
1548 * set remaining message length.
1551 xdr_set_page_base(xdr, 0, len);
1553 EXPORT_SYMBOL_GPL(xdr_enter_page);
1555 static const struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0};
1557 void xdr_buf_from_iov(const struct kvec *iov, struct xdr_buf *buf)
1559 buf->head[0] = *iov;
1560 buf->tail[0] = empty_iov;
1562 buf->buflen = buf->len = iov->iov_len;
1564 EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
1567 * xdr_buf_subsegment - set subbuf to a portion of buf
1568 * @buf: an xdr buffer
1569 * @subbuf: the result buffer
1570 * @base: beginning of range in bytes
1571 * @len: length of range in bytes
1573 * sets @subbuf to an xdr buffer representing the portion of @buf of
1574 * length @len starting at offset @base.
1576 * @buf and @subbuf may be pointers to the same struct xdr_buf.
1578 * Returns -1 if base of length are out of bounds.
1580 int xdr_buf_subsegment(const struct xdr_buf *buf, struct xdr_buf *subbuf,
1581 unsigned int base, unsigned int len)
1583 subbuf->buflen = subbuf->len = len;
1584 if (base < buf->head[0].iov_len) {
1585 subbuf->head[0].iov_base = buf->head[0].iov_base + base;
1586 subbuf->head[0].iov_len = min_t(unsigned int, len,
1587 buf->head[0].iov_len - base);
1588 len -= subbuf->head[0].iov_len;
1591 base -= buf->head[0].iov_len;
1592 subbuf->head[0].iov_base = buf->head[0].iov_base;
1593 subbuf->head[0].iov_len = 0;
1596 if (base < buf->page_len) {
1597 subbuf->page_len = min(buf->page_len - base, len);
1598 base += buf->page_base;
1599 subbuf->page_base = base & ~PAGE_MASK;
1600 subbuf->pages = &buf->pages[base >> PAGE_SHIFT];
1601 len -= subbuf->page_len;
1604 base -= buf->page_len;
1605 subbuf->pages = buf->pages;
1606 subbuf->page_base = 0;
1607 subbuf->page_len = 0;
1610 if (base < buf->tail[0].iov_len) {
1611 subbuf->tail[0].iov_base = buf->tail[0].iov_base + base;
1612 subbuf->tail[0].iov_len = min_t(unsigned int, len,
1613 buf->tail[0].iov_len - base);
1614 len -= subbuf->tail[0].iov_len;
1617 base -= buf->tail[0].iov_len;
1618 subbuf->tail[0].iov_base = buf->tail[0].iov_base;
1619 subbuf->tail[0].iov_len = 0;
1626 EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
1629 * xdr_stream_subsegment - set @subbuf to a portion of @xdr
1630 * @xdr: an xdr_stream set up for decoding
1631 * @subbuf: the result buffer
1632 * @nbytes: length of @xdr to extract, in bytes
1634 * Sets up @subbuf to represent a portion of @xdr. The portion
1635 * starts at the current offset in @xdr, and extends for a length
1636 * of @nbytes. If this is successful, @xdr is advanced to the next
1637 * XDR data item following that portion.
1640 * %true: @subbuf has been initialized, and @xdr has been advanced.
1641 * %false: a bounds error has occurred
1643 bool xdr_stream_subsegment(struct xdr_stream *xdr, struct xdr_buf *subbuf,
1644 unsigned int nbytes)
1646 unsigned int start = xdr_stream_pos(xdr);
1647 unsigned int remaining, len;
1649 /* Extract @subbuf and bounds-check the fn arguments */
1650 if (xdr_buf_subsegment(xdr->buf, subbuf, start, nbytes))
1653 /* Advance @xdr by @nbytes */
1654 for (remaining = nbytes; remaining;) {
1655 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
1658 len = (char *)xdr->end - (char *)xdr->p;
1659 if (remaining <= len) {
1660 xdr->p = (__be32 *)((char *)xdr->p +
1661 (remaining + xdr_pad_size(nbytes)));
1665 xdr->p = (__be32 *)((char *)xdr->p + len);
1670 xdr_stream_set_pos(xdr, start + nbytes);
1673 EXPORT_SYMBOL_GPL(xdr_stream_subsegment);
1676 * xdr_stream_move_subsegment - Move part of a stream to another position
1677 * @xdr: the source xdr_stream
1678 * @offset: the source offset of the segment
1679 * @target: the target offset of the segment
1680 * @length: the number of bytes to move
1682 * Moves @length bytes from @offset to @target in the xdr_stream, overwriting
1683 * anything in its space. Returns the number of bytes in the segment.
1685 unsigned int xdr_stream_move_subsegment(struct xdr_stream *xdr, unsigned int offset,
1686 unsigned int target, unsigned int length)
1691 if (offset < target) {
1692 shift = target - offset;
1693 if (xdr_buf_subsegment(xdr->buf, &buf, offset, shift + length) < 0)
1695 xdr_buf_head_shift_right(&buf, 0, length, shift);
1696 } else if (offset > target) {
1697 shift = offset - target;
1698 if (xdr_buf_subsegment(xdr->buf, &buf, target, shift + length) < 0)
1700 xdr_buf_head_shift_left(&buf, shift, length, shift);
1704 EXPORT_SYMBOL_GPL(xdr_stream_move_subsegment);
1707 * xdr_stream_zero - zero out a portion of an xdr_stream
1708 * @xdr: an xdr_stream to zero out
1709 * @offset: the starting point in the stream
1710 * @length: the number of bytes to zero
1712 unsigned int xdr_stream_zero(struct xdr_stream *xdr, unsigned int offset,
1713 unsigned int length)
1717 if (xdr_buf_subsegment(xdr->buf, &buf, offset, length) < 0)
1719 if (buf.head[0].iov_len)
1720 xdr_buf_iov_zero(buf.head, 0, buf.head[0].iov_len);
1721 if (buf.page_len > 0)
1722 xdr_buf_pages_zero(&buf, 0, buf.page_len);
1723 if (buf.tail[0].iov_len)
1724 xdr_buf_iov_zero(buf.tail, 0, buf.tail[0].iov_len);
1727 EXPORT_SYMBOL_GPL(xdr_stream_zero);
1730 * xdr_buf_trim - lop at most "len" bytes off the end of "buf"
1731 * @buf: buf to be trimmed
1732 * @len: number of bytes to reduce "buf" by
1734 * Trim an xdr_buf by the given number of bytes by fixing up the lengths. Note
1735 * that it's possible that we'll trim less than that amount if the xdr_buf is
1736 * too small, or if (for instance) it's all in the head and the parser has
1737 * already read too far into it.
1739 void xdr_buf_trim(struct xdr_buf *buf, unsigned int len)
1742 unsigned int trim = len;
1744 if (buf->tail[0].iov_len) {
1745 cur = min_t(size_t, buf->tail[0].iov_len, trim);
1746 buf->tail[0].iov_len -= cur;
1752 if (buf->page_len) {
1753 cur = min_t(unsigned int, buf->page_len, trim);
1754 buf->page_len -= cur;
1760 if (buf->head[0].iov_len) {
1761 cur = min_t(size_t, buf->head[0].iov_len, trim);
1762 buf->head[0].iov_len -= cur;
1766 buf->len -= (len - trim);
1768 EXPORT_SYMBOL_GPL(xdr_buf_trim);
1770 static void __read_bytes_from_xdr_buf(const struct xdr_buf *subbuf,
1771 void *obj, unsigned int len)
1773 unsigned int this_len;
1775 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1776 memcpy(obj, subbuf->head[0].iov_base, this_len);
1779 this_len = min_t(unsigned int, len, subbuf->page_len);
1780 _copy_from_pages(obj, subbuf->pages, subbuf->page_base, this_len);
1783 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1784 memcpy(obj, subbuf->tail[0].iov_base, this_len);
1787 /* obj is assumed to point to allocated memory of size at least len: */
1788 int read_bytes_from_xdr_buf(const struct xdr_buf *buf, unsigned int base,
1789 void *obj, unsigned int len)
1791 struct xdr_buf subbuf;
1794 status = xdr_buf_subsegment(buf, &subbuf, base, len);
1797 __read_bytes_from_xdr_buf(&subbuf, obj, len);
1800 EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf);
1802 static void __write_bytes_to_xdr_buf(const struct xdr_buf *subbuf,
1803 void *obj, unsigned int len)
1805 unsigned int this_len;
1807 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1808 memcpy(subbuf->head[0].iov_base, obj, this_len);
1811 this_len = min_t(unsigned int, len, subbuf->page_len);
1812 _copy_to_pages(subbuf->pages, subbuf->page_base, obj, this_len);
1815 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1816 memcpy(subbuf->tail[0].iov_base, obj, this_len);
1819 /* obj is assumed to point to allocated memory of size at least len: */
1820 int write_bytes_to_xdr_buf(const struct xdr_buf *buf, unsigned int base,
1821 void *obj, unsigned int len)
1823 struct xdr_buf subbuf;
1826 status = xdr_buf_subsegment(buf, &subbuf, base, len);
1829 __write_bytes_to_xdr_buf(&subbuf, obj, len);
1832 EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf);
1834 int xdr_decode_word(const struct xdr_buf *buf, unsigned int base, u32 *obj)
1839 status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
1842 *obj = be32_to_cpu(raw);
1845 EXPORT_SYMBOL_GPL(xdr_decode_word);
1847 int xdr_encode_word(const struct xdr_buf *buf, unsigned int base, u32 obj)
1849 __be32 raw = cpu_to_be32(obj);
1851 return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj));
1853 EXPORT_SYMBOL_GPL(xdr_encode_word);
1855 /* Returns 0 on success, or else a negative error code. */
1856 static int xdr_xcode_array2(const struct xdr_buf *buf, unsigned int base,
1857 struct xdr_array2_desc *desc, int encode)
1859 char *elem = NULL, *c;
1860 unsigned int copied = 0, todo, avail_here;
1861 struct page **ppages = NULL;
1865 if (xdr_encode_word(buf, base, desc->array_len) != 0)
1868 if (xdr_decode_word(buf, base, &desc->array_len) != 0 ||
1869 desc->array_len > desc->array_maxlen ||
1870 (unsigned long) base + 4 + desc->array_len *
1871 desc->elem_size > buf->len)
1879 todo = desc->array_len * desc->elem_size;
1882 if (todo && base < buf->head->iov_len) {
1883 c = buf->head->iov_base + base;
1884 avail_here = min_t(unsigned int, todo,
1885 buf->head->iov_len - base);
1888 while (avail_here >= desc->elem_size) {
1889 err = desc->xcode(desc, c);
1892 c += desc->elem_size;
1893 avail_here -= desc->elem_size;
1897 elem = kmalloc(desc->elem_size, GFP_KERNEL);
1903 err = desc->xcode(desc, elem);
1906 memcpy(c, elem, avail_here);
1908 memcpy(elem, c, avail_here);
1909 copied = avail_here;
1911 base = buf->head->iov_len; /* align to start of pages */
1914 /* process pages array */
1915 base -= buf->head->iov_len;
1916 if (todo && base < buf->page_len) {
1917 unsigned int avail_page;
1919 avail_here = min(todo, buf->page_len - base);
1922 base += buf->page_base;
1923 ppages = buf->pages + (base >> PAGE_SHIFT);
1925 avail_page = min_t(unsigned int, PAGE_SIZE - base,
1927 c = kmap(*ppages) + base;
1929 while (avail_here) {
1930 avail_here -= avail_page;
1931 if (copied || avail_page < desc->elem_size) {
1932 unsigned int l = min(avail_page,
1933 desc->elem_size - copied);
1935 elem = kmalloc(desc->elem_size,
1943 err = desc->xcode(desc, elem);
1947 memcpy(c, elem + copied, l);
1949 if (copied == desc->elem_size)
1952 memcpy(elem + copied, c, l);
1954 if (copied == desc->elem_size) {
1955 err = desc->xcode(desc, elem);
1964 while (avail_page >= desc->elem_size) {
1965 err = desc->xcode(desc, c);
1968 c += desc->elem_size;
1969 avail_page -= desc->elem_size;
1972 unsigned int l = min(avail_page,
1973 desc->elem_size - copied);
1975 elem = kmalloc(desc->elem_size,
1983 err = desc->xcode(desc, elem);
1987 memcpy(c, elem + copied, l);
1989 if (copied == desc->elem_size)
1992 memcpy(elem + copied, c, l);
1994 if (copied == desc->elem_size) {
1995 err = desc->xcode(desc, elem);
2008 avail_page = min(avail_here,
2009 (unsigned int) PAGE_SIZE);
2011 base = buf->page_len; /* align to start of tail */
2015 base -= buf->page_len;
2017 c = buf->tail->iov_base + base;
2019 unsigned int l = desc->elem_size - copied;
2022 memcpy(c, elem + copied, l);
2024 memcpy(elem + copied, c, l);
2025 err = desc->xcode(desc, elem);
2033 err = desc->xcode(desc, c);
2036 c += desc->elem_size;
2037 todo -= desc->elem_size;
2049 int xdr_decode_array2(const struct xdr_buf *buf, unsigned int base,
2050 struct xdr_array2_desc *desc)
2052 if (base >= buf->len)
2055 return xdr_xcode_array2(buf, base, desc, 0);
2057 EXPORT_SYMBOL_GPL(xdr_decode_array2);
2059 int xdr_encode_array2(const struct xdr_buf *buf, unsigned int base,
2060 struct xdr_array2_desc *desc)
2062 if ((unsigned long) base + 4 + desc->array_len * desc->elem_size >
2063 buf->head->iov_len + buf->page_len + buf->tail->iov_len)
2066 return xdr_xcode_array2(buf, base, desc, 1);
2068 EXPORT_SYMBOL_GPL(xdr_encode_array2);
2070 int xdr_process_buf(const struct xdr_buf *buf, unsigned int offset,
2072 int (*actor)(struct scatterlist *, void *), void *data)
2075 unsigned int page_len, thislen, page_offset;
2076 struct scatterlist sg[1];
2078 sg_init_table(sg, 1);
2080 if (offset >= buf->head[0].iov_len) {
2081 offset -= buf->head[0].iov_len;
2083 thislen = buf->head[0].iov_len - offset;
2086 sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
2087 ret = actor(sg, data);
2096 if (offset >= buf->page_len) {
2097 offset -= buf->page_len;
2099 page_len = buf->page_len - offset;
2103 page_offset = (offset + buf->page_base) & (PAGE_SIZE - 1);
2104 i = (offset + buf->page_base) >> PAGE_SHIFT;
2105 thislen = PAGE_SIZE - page_offset;
2107 if (thislen > page_len)
2109 sg_set_page(sg, buf->pages[i], thislen, page_offset);
2110 ret = actor(sg, data);
2113 page_len -= thislen;
2116 thislen = PAGE_SIZE;
2117 } while (page_len != 0);
2122 if (offset < buf->tail[0].iov_len) {
2123 thislen = buf->tail[0].iov_len - offset;
2126 sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
2127 ret = actor(sg, data);
2135 EXPORT_SYMBOL_GPL(xdr_process_buf);
2138 * xdr_stream_decode_opaque - Decode variable length opaque
2139 * @xdr: pointer to xdr_stream
2140 * @ptr: location to store opaque data
2141 * @size: size of storage buffer @ptr
2144 * On success, returns size of object stored in *@ptr
2145 * %-EBADMSG on XDR buffer overflow
2146 * %-EMSGSIZE on overflow of storage buffer @ptr
2148 ssize_t xdr_stream_decode_opaque(struct xdr_stream *xdr, void *ptr, size_t size)
2153 ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
2156 memcpy(ptr, p, ret);
2159 EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque);
2162 * xdr_stream_decode_opaque_dup - Decode and duplicate variable length opaque
2163 * @xdr: pointer to xdr_stream
2164 * @ptr: location to store pointer to opaque data
2165 * @maxlen: maximum acceptable object size
2166 * @gfp_flags: GFP mask to use
2169 * On success, returns size of object stored in *@ptr
2170 * %-EBADMSG on XDR buffer overflow
2171 * %-EMSGSIZE if the size of the object would exceed @maxlen
2172 * %-ENOMEM on memory allocation failure
2174 ssize_t xdr_stream_decode_opaque_dup(struct xdr_stream *xdr, void **ptr,
2175 size_t maxlen, gfp_t gfp_flags)
2180 ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
2182 *ptr = kmemdup(p, ret, gfp_flags);
2190 EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque_dup);
2193 * xdr_stream_decode_string - Decode variable length string
2194 * @xdr: pointer to xdr_stream
2195 * @str: location to store string
2196 * @size: size of storage buffer @str
2199 * On success, returns length of NUL-terminated string stored in *@str
2200 * %-EBADMSG on XDR buffer overflow
2201 * %-EMSGSIZE on overflow of storage buffer @str
2203 ssize_t xdr_stream_decode_string(struct xdr_stream *xdr, char *str, size_t size)
2208 ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
2210 memcpy(str, p, ret);
2217 EXPORT_SYMBOL_GPL(xdr_stream_decode_string);
2220 * xdr_stream_decode_string_dup - Decode and duplicate variable length string
2221 * @xdr: pointer to xdr_stream
2222 * @str: location to store pointer to string
2223 * @maxlen: maximum acceptable string length
2224 * @gfp_flags: GFP mask to use
2227 * On success, returns length of NUL-terminated string stored in *@ptr
2228 * %-EBADMSG on XDR buffer overflow
2229 * %-EMSGSIZE if the size of the string would exceed @maxlen
2230 * %-ENOMEM on memory allocation failure
2232 ssize_t xdr_stream_decode_string_dup(struct xdr_stream *xdr, char **str,
2233 size_t maxlen, gfp_t gfp_flags)
2238 ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
2240 char *s = kmemdup_nul(p, ret, gfp_flags);
2250 EXPORT_SYMBOL_GPL(xdr_stream_decode_string_dup);