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
127 xdr_terminate_string(struct xdr_buf *buf, const u32 len)
131 kaddr = kmap_atomic(buf->pages[0]);
132 kaddr[buf->page_base + len] = '\0';
133 kunmap_atomic(kaddr);
135 EXPORT_SYMBOL_GPL(xdr_terminate_string);
138 xdr_buf_pagecount(struct xdr_buf *buf)
142 return (buf->page_base + buf->page_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
146 xdr_alloc_bvec(struct xdr_buf *buf, gfp_t gfp)
148 size_t i, n = xdr_buf_pagecount(buf);
150 if (n != 0 && buf->bvec == NULL) {
151 buf->bvec = kmalloc_array(n, sizeof(buf->bvec[0]), gfp);
154 for (i = 0; i < n; i++) {
155 buf->bvec[i].bv_page = buf->pages[i];
156 buf->bvec[i].bv_len = PAGE_SIZE;
157 buf->bvec[i].bv_offset = 0;
164 xdr_free_bvec(struct xdr_buf *buf)
171 * xdr_inline_pages - Prepare receive buffer for a large reply
172 * @xdr: xdr_buf into which reply will be placed
173 * @offset: expected offset where data payload will start, in bytes
174 * @pages: vector of struct page pointers
175 * @base: offset in first page where receive should start, in bytes
176 * @len: expected size of the upper layer data payload, in bytes
180 xdr_inline_pages(struct xdr_buf *xdr, unsigned int offset,
181 struct page **pages, unsigned int base, unsigned int len)
183 struct kvec *head = xdr->head;
184 struct kvec *tail = xdr->tail;
185 char *buf = (char *)head->iov_base;
186 unsigned int buflen = head->iov_len;
188 head->iov_len = offset;
191 xdr->page_base = base;
194 tail->iov_base = buf + offset;
195 tail->iov_len = buflen - offset;
196 if ((xdr->page_len & 3) == 0)
197 tail->iov_len -= sizeof(__be32);
201 EXPORT_SYMBOL_GPL(xdr_inline_pages);
204 * Helper routines for doing 'memmove' like operations on a struct xdr_buf
208 * _shift_data_left_pages
209 * @pages: vector of pages containing both the source and dest memory area.
210 * @pgto_base: page vector address of destination
211 * @pgfrom_base: page vector address of source
212 * @len: number of bytes to copy
214 * Note: the addresses pgto_base and pgfrom_base are both calculated in
216 * if a memory area starts at byte 'base' in page 'pages[i]',
217 * then its address is given as (i << PAGE_CACHE_SHIFT) + base
218 * Alse note: pgto_base must be < pgfrom_base, but the memory areas
219 * they point to may overlap.
222 _shift_data_left_pages(struct page **pages, size_t pgto_base,
223 size_t pgfrom_base, size_t len)
225 struct page **pgfrom, **pgto;
229 BUG_ON(pgfrom_base <= pgto_base);
231 pgto = pages + (pgto_base >> PAGE_SHIFT);
232 pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);
234 pgto_base &= ~PAGE_MASK;
235 pgfrom_base &= ~PAGE_MASK;
238 if (pgto_base >= PAGE_SIZE) {
242 if (pgfrom_base >= PAGE_SIZE){
248 if (copy > (PAGE_SIZE - pgto_base))
249 copy = PAGE_SIZE - pgto_base;
250 if (copy > (PAGE_SIZE - pgfrom_base))
251 copy = PAGE_SIZE - pgfrom_base;
253 vto = kmap_atomic(*pgto);
254 if (*pgto != *pgfrom) {
255 vfrom = kmap_atomic(*pgfrom);
256 memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);
257 kunmap_atomic(vfrom);
259 memmove(vto + pgto_base, vto + pgfrom_base, copy);
260 flush_dcache_page(*pgto);
266 } while ((len -= copy) != 0);
270 _shift_data_left_tail(struct xdr_buf *buf, unsigned int pgto, size_t len)
272 struct kvec *tail = buf->tail;
274 if (len > tail->iov_len)
277 _copy_to_pages(buf->pages,
278 buf->page_base + pgto,
279 (char *)tail->iov_base,
281 tail->iov_len -= len;
283 if (tail->iov_len > 0)
284 memmove((char *)tail->iov_base,
285 tail->iov_base + len,
290 * _shift_data_right_pages
291 * @pages: vector of pages containing both the source and dest memory area.
292 * @pgto_base: page vector address of destination
293 * @pgfrom_base: page vector address of source
294 * @len: number of bytes to copy
296 * Note: the addresses pgto_base and pgfrom_base are both calculated in
298 * if a memory area starts at byte 'base' in page 'pages[i]',
299 * then its address is given as (i << PAGE_SHIFT) + base
300 * Also note: pgfrom_base must be < pgto_base, but the memory areas
301 * they point to may overlap.
304 _shift_data_right_pages(struct page **pages, size_t pgto_base,
305 size_t pgfrom_base, size_t len)
307 struct page **pgfrom, **pgto;
311 BUG_ON(pgto_base <= pgfrom_base);
316 pgto = pages + (pgto_base >> PAGE_SHIFT);
317 pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);
319 pgto_base &= ~PAGE_MASK;
320 pgfrom_base &= ~PAGE_MASK;
323 /* Are any pointers crossing a page boundary? */
324 if (pgto_base == 0) {
325 pgto_base = PAGE_SIZE;
328 if (pgfrom_base == 0) {
329 pgfrom_base = PAGE_SIZE;
334 if (copy > pgto_base)
336 if (copy > pgfrom_base)
341 vto = kmap_atomic(*pgto);
342 if (*pgto != *pgfrom) {
343 vfrom = kmap_atomic(*pgfrom);
344 memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);
345 kunmap_atomic(vfrom);
347 memmove(vto + pgto_base, vto + pgfrom_base, copy);
348 flush_dcache_page(*pgto);
351 } while ((len -= copy) != 0);
355 _shift_data_right_tail(struct xdr_buf *buf, unsigned int pgfrom, size_t len)
357 struct kvec *tail = buf->tail;
358 unsigned int tailbuf_len;
359 unsigned int result = 0;
362 tailbuf_len = buf->buflen - buf->head->iov_len - buf->page_len;
364 /* Shift the tail first */
365 if (tailbuf_len != 0) {
366 unsigned int free_space = tailbuf_len - tail->iov_len;
368 if (len < free_space)
370 if (len > free_space)
373 tail->iov_len += free_space;
376 if (tail->iov_len > len) {
377 char *p = (char *)tail->iov_base + len;
378 memmove(p, tail->iov_base, tail->iov_len - free_space);
379 result += tail->iov_len - free_space;
381 copy = tail->iov_len;
383 /* Copy from the inlined pages into the tail */
384 _copy_from_pages((char *)tail->iov_base,
386 buf->page_base + pgfrom,
396 * @pages: array of pages
397 * @pgbase: page vector address of destination
398 * @p: pointer to source data
401 * Copies data from an arbitrary memory location into an array of pages
402 * The copy is assumed to be non-overlapping.
405 _copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len)
411 pgto = pages + (pgbase >> PAGE_SHIFT);
412 pgbase &= ~PAGE_MASK;
415 copy = PAGE_SIZE - pgbase;
419 vto = kmap_atomic(*pgto);
420 memcpy(vto + pgbase, p, copy);
428 if (pgbase == PAGE_SIZE) {
429 flush_dcache_page(*pgto);
435 flush_dcache_page(*pgto);
440 * @p: pointer to destination
441 * @pages: array of pages
442 * @pgbase: offset of source data
445 * Copies data into an arbitrary memory location from an array of pages
446 * The copy is assumed to be non-overlapping.
449 _copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
451 struct page **pgfrom;
455 pgfrom = pages + (pgbase >> PAGE_SHIFT);
456 pgbase &= ~PAGE_MASK;
459 copy = PAGE_SIZE - pgbase;
463 vfrom = kmap_atomic(*pgfrom);
464 memcpy(p, vfrom + pgbase, copy);
465 kunmap_atomic(vfrom);
468 if (pgbase == PAGE_SIZE) {
474 } while ((len -= copy) != 0);
476 EXPORT_SYMBOL_GPL(_copy_from_pages);
480 * @pages: array of pages
481 * @pgbase: beginning page vector address
485 _zero_pages(struct page **pages, size_t pgbase, size_t len)
491 page = pages + (pgbase >> PAGE_SHIFT);
492 pgbase &= ~PAGE_MASK;
495 zero = PAGE_SIZE - pgbase;
499 vpage = kmap_atomic(*page);
500 memset(vpage + pgbase, 0, zero);
501 kunmap_atomic(vpage);
503 flush_dcache_page(*page);
507 } while ((len -= zero) != 0);
513 * @len: bytes to remove from buf->head[0]
515 * Shrinks XDR buffer's header kvec buf->head[0] by
516 * 'len' bytes. The extra data is not lost, but is instead
517 * moved into the inlined pages and/or the tail.
520 xdr_shrink_bufhead(struct xdr_buf *buf, size_t len)
522 struct kvec *head, *tail;
524 unsigned int pglen = buf->page_len;
531 WARN_ON_ONCE(len > head->iov_len);
532 if (len > head->iov_len)
535 /* Shift the tail first */
536 if (tail->iov_len != 0) {
537 if (tail->iov_len > len) {
538 copy = tail->iov_len - len;
539 memmove((char *)tail->iov_base + len,
540 tail->iov_base, copy);
543 /* Copy from the inlined pages into the tail */
548 if (offs >= tail->iov_len)
550 else if (copy > tail->iov_len - offs)
551 copy = tail->iov_len - offs;
553 _copy_from_pages((char *)tail->iov_base + offs,
555 buf->page_base + pglen + offs - len,
559 /* Do we also need to copy data from the head into the tail ? */
561 offs = copy = len - pglen;
562 if (copy > tail->iov_len)
563 copy = tail->iov_len;
564 memcpy(tail->iov_base,
565 (char *)head->iov_base +
566 head->iov_len - offs,
571 /* Now handle pages */
574 _shift_data_right_pages(buf->pages,
575 buf->page_base + len,
581 _copy_to_pages(buf->pages, buf->page_base,
582 (char *)head->iov_base + head->iov_len - len,
586 head->iov_len -= len;
588 /* Have we truncated the message? */
589 if (buf->len > buf->buflen)
590 buf->len = buf->buflen;
596 * xdr_shrink_pagelen - shrinks buf->pages by up to @len bytes
598 * @len: bytes to remove from buf->pages
600 * The extra data is not lost, but is instead moved into buf->tail.
601 * Returns the actual number of bytes moved.
604 xdr_shrink_pagelen(struct xdr_buf *buf, size_t len)
606 unsigned int pglen = buf->page_len;
609 if (len > buf->page_len)
610 len = buf-> page_len;
612 result = _shift_data_right_tail(buf, pglen - len, len);
613 buf->page_len -= len;
615 /* Have we truncated the message? */
616 if (buf->len > buf->buflen)
617 buf->len = buf->buflen;
623 xdr_shift_buf(struct xdr_buf *buf, size_t len)
625 xdr_shrink_bufhead(buf, len);
627 EXPORT_SYMBOL_GPL(xdr_shift_buf);
630 * xdr_stream_pos - Return the current offset from the start of the xdr_stream
631 * @xdr: pointer to struct xdr_stream
633 unsigned int xdr_stream_pos(const struct xdr_stream *xdr)
635 return (unsigned int)(XDR_QUADLEN(xdr->buf->len) - xdr->nwords) << 2;
637 EXPORT_SYMBOL_GPL(xdr_stream_pos);
640 * xdr_page_pos - Return the current offset from the start of the xdr pages
641 * @xdr: pointer to struct xdr_stream
643 unsigned int xdr_page_pos(const struct xdr_stream *xdr)
645 unsigned int pos = xdr_stream_pos(xdr);
647 WARN_ON(pos < xdr->buf->head[0].iov_len);
648 return pos - xdr->buf->head[0].iov_len;
650 EXPORT_SYMBOL_GPL(xdr_page_pos);
653 * xdr_init_encode - Initialize a struct xdr_stream for sending data.
654 * @xdr: pointer to xdr_stream struct
655 * @buf: pointer to XDR buffer in which to encode data
656 * @p: current pointer inside XDR buffer
657 * @rqst: pointer to controlling rpc_rqst, for debugging
659 * Note: at the moment the RPC client only passes the length of our
660 * scratch buffer in the xdr_buf's header kvec. Previously this
661 * meant we needed to call xdr_adjust_iovec() after encoding the
662 * data. With the new scheme, the xdr_stream manages the details
663 * of the buffer length, and takes care of adjusting the kvec
666 void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
667 struct rpc_rqst *rqst)
669 struct kvec *iov = buf->head;
670 int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len;
672 xdr_reset_scratch_buffer(xdr);
673 BUG_ON(scratch_len < 0);
676 xdr->p = (__be32 *)((char *)iov->iov_base + iov->iov_len);
677 xdr->end = (__be32 *)((char *)iov->iov_base + scratch_len);
678 BUG_ON(iov->iov_len > scratch_len);
680 if (p != xdr->p && p != NULL) {
683 BUG_ON(p < xdr->p || p > xdr->end);
684 len = (char *)p - (char *)xdr->p;
691 EXPORT_SYMBOL_GPL(xdr_init_encode);
694 * xdr_commit_encode - Ensure all data is written to buffer
695 * @xdr: pointer to xdr_stream
697 * We handle encoding across page boundaries by giving the caller a
698 * temporary location to write to, then later copying the data into
699 * place; xdr_commit_encode does that copying.
701 * Normally the caller doesn't need to call this directly, as the
702 * following xdr_reserve_space will do it. But an explicit call may be
703 * required at the end of encoding, or any other time when the xdr_buf
704 * data might be read.
706 inline void xdr_commit_encode(struct xdr_stream *xdr)
708 int shift = xdr->scratch.iov_len;
713 page = page_address(*xdr->page_ptr);
714 memcpy(xdr->scratch.iov_base, page, shift);
715 memmove(page, page + shift, (void *)xdr->p - page);
716 xdr_reset_scratch_buffer(xdr);
718 EXPORT_SYMBOL_GPL(xdr_commit_encode);
720 static __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr,
725 int frag1bytes, frag2bytes;
727 if (nbytes > PAGE_SIZE)
728 goto out_overflow; /* Bigger buffers require special handling */
729 if (xdr->buf->len + nbytes > xdr->buf->buflen)
730 goto out_overflow; /* Sorry, we're totally out of space */
731 frag1bytes = (xdr->end - xdr->p) << 2;
732 frag2bytes = nbytes - frag1bytes;
734 xdr->iov->iov_len += frag1bytes;
736 xdr->buf->page_len += frag1bytes;
740 * If the last encode didn't end exactly on a page boundary, the
741 * next one will straddle boundaries. Encode into the next
742 * page, then copy it back later in xdr_commit_encode. We use
743 * the "scratch" iov to track any temporarily unused fragment of
744 * space at the end of the previous buffer:
746 xdr_set_scratch_buffer(xdr, xdr->p, frag1bytes);
747 p = page_address(*xdr->page_ptr);
749 * Note this is where the next encode will start after we've
750 * shifted this one back:
752 xdr->p = (void *)p + frag2bytes;
753 space_left = xdr->buf->buflen - xdr->buf->len;
754 xdr->end = (void *)p + min_t(int, space_left, PAGE_SIZE);
755 xdr->buf->page_len += frag2bytes;
756 xdr->buf->len += nbytes;
759 trace_rpc_xdr_overflow(xdr, nbytes);
764 * xdr_reserve_space - Reserve buffer space for sending
765 * @xdr: pointer to xdr_stream
766 * @nbytes: number of bytes to reserve
768 * Checks that we have enough buffer space to encode 'nbytes' more
769 * bytes of data. If so, update the total xdr_buf length, and
770 * adjust the length of the current kvec.
772 __be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
777 xdr_commit_encode(xdr);
778 /* align nbytes on the next 32-bit boundary */
781 q = p + (nbytes >> 2);
782 if (unlikely(q > xdr->end || q < p))
783 return xdr_get_next_encode_buffer(xdr, nbytes);
786 xdr->iov->iov_len += nbytes;
788 xdr->buf->page_len += nbytes;
789 xdr->buf->len += nbytes;
792 EXPORT_SYMBOL_GPL(xdr_reserve_space);
796 * xdr_reserve_space_vec - Reserves a large amount of buffer space for sending
797 * @xdr: pointer to xdr_stream
798 * @vec: pointer to a kvec array
799 * @nbytes: number of bytes to reserve
801 * Reserves enough buffer space to encode 'nbytes' of data and stores the
802 * pointers in 'vec'. The size argument passed to xdr_reserve_space() is
803 * determined based on the number of bytes remaining in the current page to
804 * avoid invalidating iov_base pointers when xdr_commit_encode() is called.
806 int xdr_reserve_space_vec(struct xdr_stream *xdr, struct kvec *vec, size_t nbytes)
813 * svcrdma requires every READ payload to start somewhere
816 if (xdr->iov == xdr->buf->head) {
822 thislen = xdr->buf->page_len % PAGE_SIZE;
823 thislen = min_t(size_t, nbytes, PAGE_SIZE - thislen);
825 p = xdr_reserve_space(xdr, thislen);
830 vec[v].iov_len = thislen;
837 EXPORT_SYMBOL_GPL(xdr_reserve_space_vec);
840 * xdr_truncate_encode - truncate an encode buffer
841 * @xdr: pointer to xdr_stream
842 * @len: new length of buffer
844 * Truncates the xdr stream, so that xdr->buf->len == len,
845 * and xdr->p points at offset len from the start of the buffer, and
846 * head, tail, and page lengths are adjusted to correspond.
848 * If this means moving xdr->p to a different buffer, we assume that
849 * the end pointer should be set to the end of the current page,
850 * except in the case of the head buffer when we assume the head
851 * buffer's current length represents the end of the available buffer.
853 * This is *not* safe to use on a buffer that already has inlined page
854 * cache pages (as in a zero-copy server read reply), except for the
855 * simple case of truncating from one position in the tail to another.
858 void xdr_truncate_encode(struct xdr_stream *xdr, size_t len)
860 struct xdr_buf *buf = xdr->buf;
861 struct kvec *head = buf->head;
862 struct kvec *tail = buf->tail;
866 if (len > buf->len) {
870 xdr_commit_encode(xdr);
872 fraglen = min_t(int, buf->len - len, tail->iov_len);
873 tail->iov_len -= fraglen;
876 xdr->p = tail->iov_base + tail->iov_len;
877 WARN_ON_ONCE(!xdr->end);
878 WARN_ON_ONCE(!xdr->iov);
881 WARN_ON_ONCE(fraglen);
882 fraglen = min_t(int, buf->len - len, buf->page_len);
883 buf->page_len -= fraglen;
886 new = buf->page_base + buf->page_len;
888 xdr->page_ptr = buf->pages + (new >> PAGE_SHIFT);
891 xdr->p = page_address(*xdr->page_ptr);
892 xdr->end = (void *)xdr->p + PAGE_SIZE;
893 xdr->p = (void *)xdr->p + (new % PAGE_SIZE);
894 WARN_ON_ONCE(xdr->iov);
898 xdr->end = head->iov_base + head->iov_len;
899 /* (otherwise assume xdr->end is already set) */
903 xdr->p = head->iov_base + head->iov_len;
904 xdr->iov = buf->head;
906 EXPORT_SYMBOL(xdr_truncate_encode);
909 * xdr_restrict_buflen - decrease available buffer space
910 * @xdr: pointer to xdr_stream
911 * @newbuflen: new maximum number of bytes available
913 * Adjust our idea of how much space is available in the buffer.
914 * If we've already used too much space in the buffer, returns -1.
915 * If the available space is already smaller than newbuflen, returns 0
916 * and does nothing. Otherwise, adjusts xdr->buf->buflen to newbuflen
917 * and ensures xdr->end is set at most offset newbuflen from the start
920 int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen)
922 struct xdr_buf *buf = xdr->buf;
923 int left_in_this_buf = (void *)xdr->end - (void *)xdr->p;
924 int end_offset = buf->len + left_in_this_buf;
926 if (newbuflen < 0 || newbuflen < buf->len)
928 if (newbuflen > buf->buflen)
930 if (newbuflen < end_offset)
931 xdr->end = (void *)xdr->end + newbuflen - end_offset;
932 buf->buflen = newbuflen;
935 EXPORT_SYMBOL(xdr_restrict_buflen);
938 * xdr_write_pages - Insert a list of pages into an XDR buffer for sending
939 * @xdr: pointer to xdr_stream
940 * @pages: list of pages
941 * @base: offset of first byte
942 * @len: length of data in bytes
945 void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base,
948 struct xdr_buf *buf = xdr->buf;
949 struct kvec *iov = buf->tail;
951 buf->page_base = base;
954 iov->iov_base = (char *)xdr->p;
959 unsigned int pad = 4 - (len & 3);
961 BUG_ON(xdr->p >= xdr->end);
962 iov->iov_base = (char *)xdr->p + (len & 3);
970 EXPORT_SYMBOL_GPL(xdr_write_pages);
972 static void xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
975 if (len > iov->iov_len)
977 xdr->p = (__be32*)iov->iov_base;
978 xdr->end = (__be32*)(iov->iov_base + len);
980 xdr->page_ptr = NULL;
983 static int xdr_set_page_base(struct xdr_stream *xdr,
984 unsigned int base, unsigned int len)
992 maxlen = xdr->buf->page_len;
999 base += xdr->buf->page_base;
1001 pgnr = base >> PAGE_SHIFT;
1002 xdr->page_ptr = &xdr->buf->pages[pgnr];
1003 kaddr = page_address(*xdr->page_ptr);
1005 pgoff = base & ~PAGE_MASK;
1006 xdr->p = (__be32*)(kaddr + pgoff);
1008 pgend = pgoff + len;
1009 if (pgend > PAGE_SIZE)
1011 xdr->end = (__be32*)(kaddr + pgend);
1016 static void xdr_set_page(struct xdr_stream *xdr, unsigned int base,
1019 if (xdr_set_page_base(xdr, base, len) < 0)
1020 xdr_set_iov(xdr, xdr->buf->tail, xdr->nwords << 2);
1023 static void xdr_set_next_page(struct xdr_stream *xdr)
1025 unsigned int newbase;
1027 newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT;
1028 newbase -= xdr->buf->page_base;
1030 xdr_set_page(xdr, newbase, PAGE_SIZE);
1033 static bool xdr_set_next_buffer(struct xdr_stream *xdr)
1035 if (xdr->page_ptr != NULL)
1036 xdr_set_next_page(xdr);
1037 else if (xdr->iov == xdr->buf->head) {
1038 xdr_set_page(xdr, 0, PAGE_SIZE);
1040 return xdr->p != xdr->end;
1044 * xdr_init_decode - Initialize an xdr_stream for decoding data.
1045 * @xdr: pointer to xdr_stream struct
1046 * @buf: pointer to XDR buffer from which to decode data
1047 * @p: current pointer inside XDR buffer
1048 * @rqst: pointer to controlling rpc_rqst, for debugging
1050 void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
1051 struct rpc_rqst *rqst)
1054 xdr_reset_scratch_buffer(xdr);
1055 xdr->nwords = XDR_QUADLEN(buf->len);
1056 if (buf->head[0].iov_len != 0)
1057 xdr_set_iov(xdr, buf->head, buf->len);
1058 else if (buf->page_len != 0)
1059 xdr_set_page_base(xdr, 0, buf->len);
1061 xdr_set_iov(xdr, buf->head, buf->len);
1062 if (p != NULL && p > xdr->p && xdr->end >= p) {
1063 xdr->nwords -= p - xdr->p;
1068 EXPORT_SYMBOL_GPL(xdr_init_decode);
1071 * xdr_init_decode_pages - Initialize an xdr_stream for decoding into pages
1072 * @xdr: pointer to xdr_stream struct
1073 * @buf: pointer to XDR buffer from which to decode data
1074 * @pages: list of pages to decode into
1075 * @len: length in bytes of buffer in pages
1077 void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
1078 struct page **pages, unsigned int len)
1080 memset(buf, 0, sizeof(*buf));
1082 buf->page_len = len;
1085 xdr_init_decode(xdr, buf, NULL, NULL);
1087 EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
1089 static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
1091 unsigned int nwords = XDR_QUADLEN(nbytes);
1093 __be32 *q = p + nwords;
1095 if (unlikely(nwords > xdr->nwords || q > xdr->end || q < p))
1098 xdr->nwords -= nwords;
1102 static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes)
1105 char *cpdest = xdr->scratch.iov_base;
1106 size_t cplen = (char *)xdr->end - (char *)xdr->p;
1108 if (nbytes > xdr->scratch.iov_len)
1110 p = __xdr_inline_decode(xdr, cplen);
1113 memcpy(cpdest, p, cplen);
1114 if (!xdr_set_next_buffer(xdr))
1118 p = __xdr_inline_decode(xdr, nbytes);
1121 memcpy(cpdest, p, nbytes);
1122 return xdr->scratch.iov_base;
1124 trace_rpc_xdr_overflow(xdr, nbytes);
1129 * xdr_inline_decode - Retrieve XDR data to decode
1130 * @xdr: pointer to xdr_stream struct
1131 * @nbytes: number of bytes of data to decode
1133 * Check if the input buffer is long enough to enable us to decode
1134 * 'nbytes' more bytes of data starting at the current position.
1135 * If so return the current pointer, then update the current
1138 __be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
1142 if (unlikely(nbytes == 0))
1144 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
1146 p = __xdr_inline_decode(xdr, nbytes);
1149 return xdr_copy_to_scratch(xdr, nbytes);
1151 trace_rpc_xdr_overflow(xdr, nbytes);
1154 EXPORT_SYMBOL_GPL(xdr_inline_decode);
1156 static void xdr_realign_pages(struct xdr_stream *xdr)
1158 struct xdr_buf *buf = xdr->buf;
1159 struct kvec *iov = buf->head;
1160 unsigned int cur = xdr_stream_pos(xdr);
1161 unsigned int copied, offset;
1163 /* Realign pages to current pointer position */
1164 if (iov->iov_len > cur) {
1165 offset = iov->iov_len - cur;
1166 copied = xdr_shrink_bufhead(buf, offset);
1167 trace_rpc_xdr_alignment(xdr, offset, copied);
1168 xdr->nwords = XDR_QUADLEN(buf->len - cur);
1172 static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len)
1174 struct xdr_buf *buf = xdr->buf;
1175 unsigned int nwords = XDR_QUADLEN(len);
1176 unsigned int cur = xdr_stream_pos(xdr);
1177 unsigned int copied, offset;
1179 if (xdr->nwords == 0)
1182 xdr_realign_pages(xdr);
1183 if (nwords > xdr->nwords) {
1184 nwords = xdr->nwords;
1187 if (buf->page_len <= len)
1188 len = buf->page_len;
1189 else if (nwords < xdr->nwords) {
1190 /* Truncate page data and move it into the tail */
1191 offset = buf->page_len - len;
1192 copied = xdr_shrink_pagelen(buf, offset);
1193 trace_rpc_xdr_alignment(xdr, offset, copied);
1194 xdr->nwords = XDR_QUADLEN(buf->len - cur);
1200 * xdr_read_pages - Ensure page-based XDR data to decode is aligned at current pointer position
1201 * @xdr: pointer to xdr_stream struct
1202 * @len: number of bytes of page data
1204 * Moves data beyond the current pointer position from the XDR head[] buffer
1205 * into the page list. Any data that lies beyond current position + "len"
1206 * bytes is moved into the XDR tail[].
1208 * Returns the number of XDR encoded bytes now contained in the pages
1210 unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
1212 struct xdr_buf *buf = xdr->buf;
1214 unsigned int nwords;
1216 unsigned int padding;
1218 len = xdr_align_pages(xdr, len);
1221 nwords = XDR_QUADLEN(len);
1222 padding = (nwords << 2) - len;
1223 xdr->iov = iov = buf->tail;
1224 /* Compute remaining message length. */
1225 end = ((xdr->nwords - nwords) << 2) + padding;
1226 if (end > iov->iov_len)
1230 * Position current pointer at beginning of tail, and
1231 * set remaining message length.
1233 xdr->p = (__be32 *)((char *)iov->iov_base + padding);
1234 xdr->end = (__be32 *)((char *)iov->iov_base + end);
1235 xdr->page_ptr = NULL;
1236 xdr->nwords = XDR_QUADLEN(end - padding);
1239 EXPORT_SYMBOL_GPL(xdr_read_pages);
1241 uint64_t xdr_align_data(struct xdr_stream *xdr, uint64_t offset, uint32_t length)
1243 struct xdr_buf *buf = xdr->buf;
1244 unsigned int from, bytes;
1245 unsigned int shift = 0;
1247 if ((offset + length) < offset ||
1248 (offset + length) > buf->page_len)
1249 length = buf->page_len - offset;
1251 xdr_realign_pages(xdr);
1252 from = xdr_page_pos(xdr);
1253 bytes = xdr->nwords << 2;
1257 /* Move page data to the left */
1258 if (from > offset) {
1259 shift = min_t(unsigned int, bytes, buf->page_len - from);
1260 _shift_data_left_pages(buf->pages,
1261 buf->page_base + offset,
1262 buf->page_base + from,
1266 /* Move tail data into the pages, if necessary */
1268 _shift_data_left_tail(buf, offset + shift, bytes);
1271 xdr->nwords -= XDR_QUADLEN(length);
1272 xdr_set_page(xdr, from + length, PAGE_SIZE);
1275 EXPORT_SYMBOL_GPL(xdr_align_data);
1277 uint64_t xdr_expand_hole(struct xdr_stream *xdr, uint64_t offset, uint64_t length)
1279 struct xdr_buf *buf = xdr->buf;
1282 unsigned int truncated = 0;
1284 if ((offset + length) < offset ||
1285 (offset + length) > buf->page_len)
1286 length = buf->page_len - offset;
1288 xdr_realign_pages(xdr);
1289 from = xdr_page_pos(xdr);
1290 bytes = xdr->nwords << 2;
1292 if (offset + length + bytes > buf->page_len) {
1293 unsigned int shift = (offset + length + bytes) - buf->page_len;
1294 unsigned int res = _shift_data_right_tail(buf, from + bytes - shift, shift);
1295 truncated = shift - res;
1296 xdr->nwords -= XDR_QUADLEN(truncated);
1300 /* Now move the page data over and zero pages */
1302 _shift_data_right_pages(buf->pages,
1303 buf->page_base + offset + length,
1304 buf->page_base + from,
1306 _zero_pages(buf->pages, buf->page_base + offset, length);
1308 buf->len += length - (from - offset) - truncated;
1309 xdr_set_page(xdr, offset + length, PAGE_SIZE);
1312 EXPORT_SYMBOL_GPL(xdr_expand_hole);
1315 * xdr_enter_page - decode data from the XDR page
1316 * @xdr: pointer to xdr_stream struct
1317 * @len: number of bytes of page data
1319 * Moves data beyond the current pointer position from the XDR head[] buffer
1320 * into the page list. Any data that lies beyond current position + "len"
1321 * bytes is moved into the XDR tail[]. The current pointer is then
1322 * repositioned at the beginning of the first XDR page.
1324 void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
1326 len = xdr_align_pages(xdr, len);
1328 * Position current pointer at beginning of tail, and
1329 * set remaining message length.
1332 xdr_set_page_base(xdr, 0, len);
1334 EXPORT_SYMBOL_GPL(xdr_enter_page);
1336 static const struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0};
1339 xdr_buf_from_iov(struct kvec *iov, struct xdr_buf *buf)
1341 buf->head[0] = *iov;
1342 buf->tail[0] = empty_iov;
1344 buf->buflen = buf->len = iov->iov_len;
1346 EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
1349 * xdr_buf_subsegment - set subbuf to a portion of buf
1350 * @buf: an xdr buffer
1351 * @subbuf: the result buffer
1352 * @base: beginning of range in bytes
1353 * @len: length of range in bytes
1355 * sets @subbuf to an xdr buffer representing the portion of @buf of
1356 * length @len starting at offset @base.
1358 * @buf and @subbuf may be pointers to the same struct xdr_buf.
1360 * Returns -1 if base of length are out of bounds.
1362 int xdr_buf_subsegment(const struct xdr_buf *buf, struct xdr_buf *subbuf,
1363 unsigned int base, unsigned int len)
1365 subbuf->buflen = subbuf->len = len;
1366 if (base < buf->head[0].iov_len) {
1367 subbuf->head[0].iov_base = buf->head[0].iov_base + base;
1368 subbuf->head[0].iov_len = min_t(unsigned int, len,
1369 buf->head[0].iov_len - base);
1370 len -= subbuf->head[0].iov_len;
1373 base -= buf->head[0].iov_len;
1374 subbuf->head[0].iov_base = buf->head[0].iov_base;
1375 subbuf->head[0].iov_len = 0;
1378 if (base < buf->page_len) {
1379 subbuf->page_len = min(buf->page_len - base, len);
1380 base += buf->page_base;
1381 subbuf->page_base = base & ~PAGE_MASK;
1382 subbuf->pages = &buf->pages[base >> PAGE_SHIFT];
1383 len -= subbuf->page_len;
1386 base -= buf->page_len;
1387 subbuf->pages = buf->pages;
1388 subbuf->page_base = 0;
1389 subbuf->page_len = 0;
1392 if (base < buf->tail[0].iov_len) {
1393 subbuf->tail[0].iov_base = buf->tail[0].iov_base + base;
1394 subbuf->tail[0].iov_len = min_t(unsigned int, len,
1395 buf->tail[0].iov_len - base);
1396 len -= subbuf->tail[0].iov_len;
1399 base -= buf->tail[0].iov_len;
1400 subbuf->tail[0].iov_base = buf->tail[0].iov_base;
1401 subbuf->tail[0].iov_len = 0;
1408 EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
1411 * xdr_stream_subsegment - set @subbuf to a portion of @xdr
1412 * @xdr: an xdr_stream set up for decoding
1413 * @subbuf: the result buffer
1414 * @nbytes: length of @xdr to extract, in bytes
1416 * Sets up @subbuf to represent a portion of @xdr. The portion
1417 * starts at the current offset in @xdr, and extends for a length
1418 * of @nbytes. If this is successful, @xdr is advanced to the next
1419 * position following that portion.
1422 * %true: @subbuf has been initialized, and @xdr has been advanced.
1423 * %false: a bounds error has occurred
1425 bool xdr_stream_subsegment(struct xdr_stream *xdr, struct xdr_buf *subbuf,
1426 unsigned int nbytes)
1428 unsigned int remaining, offset, len;
1430 if (xdr_buf_subsegment(xdr->buf, subbuf, xdr_stream_pos(xdr), nbytes))
1433 if (subbuf->head[0].iov_len)
1434 if (!__xdr_inline_decode(xdr, subbuf->head[0].iov_len))
1437 remaining = subbuf->page_len;
1438 offset = subbuf->page_base;
1440 len = min_t(unsigned int, remaining, PAGE_SIZE) - offset;
1442 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
1444 if (!__xdr_inline_decode(xdr, len))
1453 EXPORT_SYMBOL_GPL(xdr_stream_subsegment);
1456 * xdr_buf_trim - lop at most "len" bytes off the end of "buf"
1457 * @buf: buf to be trimmed
1458 * @len: number of bytes to reduce "buf" by
1460 * Trim an xdr_buf by the given number of bytes by fixing up the lengths. Note
1461 * that it's possible that we'll trim less than that amount if the xdr_buf is
1462 * too small, or if (for instance) it's all in the head and the parser has
1463 * already read too far into it.
1465 void xdr_buf_trim(struct xdr_buf *buf, unsigned int len)
1468 unsigned int trim = len;
1470 if (buf->tail[0].iov_len) {
1471 cur = min_t(size_t, buf->tail[0].iov_len, trim);
1472 buf->tail[0].iov_len -= cur;
1478 if (buf->page_len) {
1479 cur = min_t(unsigned int, buf->page_len, trim);
1480 buf->page_len -= cur;
1486 if (buf->head[0].iov_len) {
1487 cur = min_t(size_t, buf->head[0].iov_len, trim);
1488 buf->head[0].iov_len -= cur;
1492 buf->len -= (len - trim);
1494 EXPORT_SYMBOL_GPL(xdr_buf_trim);
1496 static void __read_bytes_from_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
1498 unsigned int this_len;
1500 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1501 memcpy(obj, subbuf->head[0].iov_base, this_len);
1504 this_len = min_t(unsigned int, len, subbuf->page_len);
1506 _copy_from_pages(obj, subbuf->pages, subbuf->page_base, this_len);
1509 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1510 memcpy(obj, subbuf->tail[0].iov_base, this_len);
1513 /* obj is assumed to point to allocated memory of size at least len: */
1514 int read_bytes_from_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
1516 struct xdr_buf subbuf;
1519 status = xdr_buf_subsegment(buf, &subbuf, base, len);
1522 __read_bytes_from_xdr_buf(&subbuf, obj, len);
1525 EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf);
1527 static void __write_bytes_to_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
1529 unsigned int this_len;
1531 this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1532 memcpy(subbuf->head[0].iov_base, obj, this_len);
1535 this_len = min_t(unsigned int, len, subbuf->page_len);
1537 _copy_to_pages(subbuf->pages, subbuf->page_base, obj, this_len);
1540 this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1541 memcpy(subbuf->tail[0].iov_base, obj, this_len);
1544 /* obj is assumed to point to allocated memory of size at least len: */
1545 int write_bytes_to_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
1547 struct xdr_buf subbuf;
1550 status = xdr_buf_subsegment(buf, &subbuf, base, len);
1553 __write_bytes_to_xdr_buf(&subbuf, obj, len);
1556 EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf);
1559 xdr_decode_word(struct xdr_buf *buf, unsigned int base, u32 *obj)
1564 status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
1567 *obj = be32_to_cpu(raw);
1570 EXPORT_SYMBOL_GPL(xdr_decode_word);
1573 xdr_encode_word(struct xdr_buf *buf, unsigned int base, u32 obj)
1575 __be32 raw = cpu_to_be32(obj);
1577 return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj));
1579 EXPORT_SYMBOL_GPL(xdr_encode_word);
1581 /* Returns 0 on success, or else a negative error code. */
1583 xdr_xcode_array2(struct xdr_buf *buf, unsigned int base,
1584 struct xdr_array2_desc *desc, int encode)
1586 char *elem = NULL, *c;
1587 unsigned int copied = 0, todo, avail_here;
1588 struct page **ppages = NULL;
1592 if (xdr_encode_word(buf, base, desc->array_len) != 0)
1595 if (xdr_decode_word(buf, base, &desc->array_len) != 0 ||
1596 desc->array_len > desc->array_maxlen ||
1597 (unsigned long) base + 4 + desc->array_len *
1598 desc->elem_size > buf->len)
1606 todo = desc->array_len * desc->elem_size;
1609 if (todo && base < buf->head->iov_len) {
1610 c = buf->head->iov_base + base;
1611 avail_here = min_t(unsigned int, todo,
1612 buf->head->iov_len - base);
1615 while (avail_here >= desc->elem_size) {
1616 err = desc->xcode(desc, c);
1619 c += desc->elem_size;
1620 avail_here -= desc->elem_size;
1624 elem = kmalloc(desc->elem_size, GFP_KERNEL);
1630 err = desc->xcode(desc, elem);
1633 memcpy(c, elem, avail_here);
1635 memcpy(elem, c, avail_here);
1636 copied = avail_here;
1638 base = buf->head->iov_len; /* align to start of pages */
1641 /* process pages array */
1642 base -= buf->head->iov_len;
1643 if (todo && base < buf->page_len) {
1644 unsigned int avail_page;
1646 avail_here = min(todo, buf->page_len - base);
1649 base += buf->page_base;
1650 ppages = buf->pages + (base >> PAGE_SHIFT);
1652 avail_page = min_t(unsigned int, PAGE_SIZE - base,
1654 c = kmap(*ppages) + base;
1656 while (avail_here) {
1657 avail_here -= avail_page;
1658 if (copied || avail_page < desc->elem_size) {
1659 unsigned int l = min(avail_page,
1660 desc->elem_size - copied);
1662 elem = kmalloc(desc->elem_size,
1670 err = desc->xcode(desc, elem);
1674 memcpy(c, elem + copied, l);
1676 if (copied == desc->elem_size)
1679 memcpy(elem + copied, c, l);
1681 if (copied == desc->elem_size) {
1682 err = desc->xcode(desc, elem);
1691 while (avail_page >= desc->elem_size) {
1692 err = desc->xcode(desc, c);
1695 c += desc->elem_size;
1696 avail_page -= desc->elem_size;
1699 unsigned int l = min(avail_page,
1700 desc->elem_size - copied);
1702 elem = kmalloc(desc->elem_size,
1710 err = desc->xcode(desc, elem);
1714 memcpy(c, elem + copied, l);
1716 if (copied == desc->elem_size)
1719 memcpy(elem + copied, c, l);
1721 if (copied == desc->elem_size) {
1722 err = desc->xcode(desc, elem);
1735 avail_page = min(avail_here,
1736 (unsigned int) PAGE_SIZE);
1738 base = buf->page_len; /* align to start of tail */
1742 base -= buf->page_len;
1744 c = buf->tail->iov_base + base;
1746 unsigned int l = desc->elem_size - copied;
1749 memcpy(c, elem + copied, l);
1751 memcpy(elem + copied, c, l);
1752 err = desc->xcode(desc, elem);
1760 err = desc->xcode(desc, c);
1763 c += desc->elem_size;
1764 todo -= desc->elem_size;
1777 xdr_decode_array2(struct xdr_buf *buf, unsigned int base,
1778 struct xdr_array2_desc *desc)
1780 if (base >= buf->len)
1783 return xdr_xcode_array2(buf, base, desc, 0);
1785 EXPORT_SYMBOL_GPL(xdr_decode_array2);
1788 xdr_encode_array2(struct xdr_buf *buf, unsigned int base,
1789 struct xdr_array2_desc *desc)
1791 if ((unsigned long) base + 4 + desc->array_len * desc->elem_size >
1792 buf->head->iov_len + buf->page_len + buf->tail->iov_len)
1795 return xdr_xcode_array2(buf, base, desc, 1);
1797 EXPORT_SYMBOL_GPL(xdr_encode_array2);
1800 xdr_process_buf(struct xdr_buf *buf, unsigned int offset, unsigned int len,
1801 int (*actor)(struct scatterlist *, void *), void *data)
1804 unsigned int page_len, thislen, page_offset;
1805 struct scatterlist sg[1];
1807 sg_init_table(sg, 1);
1809 if (offset >= buf->head[0].iov_len) {
1810 offset -= buf->head[0].iov_len;
1812 thislen = buf->head[0].iov_len - offset;
1815 sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
1816 ret = actor(sg, data);
1825 if (offset >= buf->page_len) {
1826 offset -= buf->page_len;
1828 page_len = buf->page_len - offset;
1832 page_offset = (offset + buf->page_base) & (PAGE_SIZE - 1);
1833 i = (offset + buf->page_base) >> PAGE_SHIFT;
1834 thislen = PAGE_SIZE - page_offset;
1836 if (thislen > page_len)
1838 sg_set_page(sg, buf->pages[i], thislen, page_offset);
1839 ret = actor(sg, data);
1842 page_len -= thislen;
1845 thislen = PAGE_SIZE;
1846 } while (page_len != 0);
1851 if (offset < buf->tail[0].iov_len) {
1852 thislen = buf->tail[0].iov_len - offset;
1855 sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
1856 ret = actor(sg, data);
1864 EXPORT_SYMBOL_GPL(xdr_process_buf);
1867 * xdr_stream_decode_opaque - Decode variable length opaque
1868 * @xdr: pointer to xdr_stream
1869 * @ptr: location to store opaque data
1870 * @size: size of storage buffer @ptr
1873 * On success, returns size of object stored in *@ptr
1874 * %-EBADMSG on XDR buffer overflow
1875 * %-EMSGSIZE on overflow of storage buffer @ptr
1877 ssize_t xdr_stream_decode_opaque(struct xdr_stream *xdr, void *ptr, size_t size)
1882 ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
1885 memcpy(ptr, p, ret);
1888 EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque);
1891 * xdr_stream_decode_opaque_dup - Decode and duplicate variable length opaque
1892 * @xdr: pointer to xdr_stream
1893 * @ptr: location to store pointer to opaque data
1894 * @maxlen: maximum acceptable object size
1895 * @gfp_flags: GFP mask to use
1898 * On success, returns size of object stored in *@ptr
1899 * %-EBADMSG on XDR buffer overflow
1900 * %-EMSGSIZE if the size of the object would exceed @maxlen
1901 * %-ENOMEM on memory allocation failure
1903 ssize_t xdr_stream_decode_opaque_dup(struct xdr_stream *xdr, void **ptr,
1904 size_t maxlen, gfp_t gfp_flags)
1909 ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
1911 *ptr = kmemdup(p, ret, gfp_flags);
1919 EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque_dup);
1922 * xdr_stream_decode_string - Decode variable length string
1923 * @xdr: pointer to xdr_stream
1924 * @str: location to store string
1925 * @size: size of storage buffer @str
1928 * On success, returns length of NUL-terminated string stored in *@str
1929 * %-EBADMSG on XDR buffer overflow
1930 * %-EMSGSIZE on overflow of storage buffer @str
1932 ssize_t xdr_stream_decode_string(struct xdr_stream *xdr, char *str, size_t size)
1937 ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
1939 memcpy(str, p, ret);
1946 EXPORT_SYMBOL_GPL(xdr_stream_decode_string);
1949 * xdr_stream_decode_string_dup - Decode and duplicate variable length string
1950 * @xdr: pointer to xdr_stream
1951 * @str: location to store pointer to string
1952 * @maxlen: maximum acceptable string length
1953 * @gfp_flags: GFP mask to use
1956 * On success, returns length of NUL-terminated string stored in *@ptr
1957 * %-EBADMSG on XDR buffer overflow
1958 * %-EMSGSIZE if the size of the string would exceed @maxlen
1959 * %-ENOMEM on memory allocation failure
1961 ssize_t xdr_stream_decode_string_dup(struct xdr_stream *xdr, char **str,
1962 size_t maxlen, gfp_t gfp_flags)
1967 ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
1969 char *s = kmalloc(ret + 1, gfp_flags);
1981 EXPORT_SYMBOL_GPL(xdr_stream_decode_string_dup);