diff options
Diffstat (limited to 'net/sunrpc/xdr.c')
| -rw-r--r-- | net/sunrpc/xdr.c | 595 |
1 files changed, 499 insertions, 96 deletions
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c index 8bd690c48b6..23fb4e75e24 100644 --- a/net/sunrpc/xdr.c +++ b/net/sunrpc/xdr.c @@ -7,6 +7,7 @@ */ #include <linux/module.h> +#include <linux/slab.h> #include <linux/types.h> #include <linux/string.h> #include <linux/kernel.h> @@ -110,33 +111,22 @@ xdr_decode_string_inplace(__be32 *p, char **sp, } EXPORT_SYMBOL_GPL(xdr_decode_string_inplace); +/** + * xdr_terminate_string - '\0'-terminate a string residing in an xdr_buf + * @buf: XDR buffer where string resides + * @len: length of string, in bytes + * + */ void -xdr_encode_pages(struct xdr_buf *xdr, struct page **pages, unsigned int base, - unsigned int len) +xdr_terminate_string(struct xdr_buf *buf, const u32 len) { - struct kvec *tail = xdr->tail; - u32 *p; - - xdr->pages = pages; - xdr->page_base = base; - xdr->page_len = len; - - p = (u32 *)xdr->head[0].iov_base + XDR_QUADLEN(xdr->head[0].iov_len); - tail->iov_base = p; - tail->iov_len = 0; - - if (len & 3) { - unsigned int pad = 4 - (len & 3); + char *kaddr; - *p = 0; - tail->iov_base = (char *)p + (len & 3); - tail->iov_len = pad; - len += pad; - } - xdr->buflen += len; - xdr->len += len; + kaddr = kmap_atomic(buf->pages[0]); + kaddr[buf->page_base + len] = '\0'; + kunmap_atomic(kaddr); } -EXPORT_SYMBOL_GPL(xdr_encode_pages); +EXPORT_SYMBOL_GPL(xdr_terminate_string); void xdr_inline_pages(struct xdr_buf *xdr, unsigned int offset, @@ -162,7 +152,9 @@ EXPORT_SYMBOL_GPL(xdr_inline_pages); /* * Helper routines for doing 'memmove' like operations on a struct xdr_buf - * + */ + +/** * _shift_data_right_pages * @pages: vector of pages containing both the source and dest memory area. * @pgto_base: page vector address of destination @@ -214,17 +206,20 @@ _shift_data_right_pages(struct page **pages, size_t pgto_base, pgto_base -= copy; pgfrom_base -= copy; - vto = kmap_atomic(*pgto, KM_USER0); - vfrom = kmap_atomic(*pgfrom, KM_USER1); - memmove(vto + pgto_base, vfrom + pgfrom_base, copy); + vto = kmap_atomic(*pgto); + if (*pgto != *pgfrom) { + vfrom = kmap_atomic(*pgfrom); + memcpy(vto + pgto_base, vfrom + pgfrom_base, copy); + kunmap_atomic(vfrom); + } else + memmove(vto + pgto_base, vto + pgfrom_base, copy); flush_dcache_page(*pgto); - kunmap_atomic(vfrom, KM_USER1); - kunmap_atomic(vto, KM_USER0); + kunmap_atomic(vto); } while ((len -= copy) != 0); } -/* +/** * _copy_to_pages * @pages: array of pages * @pgbase: page vector address of destination @@ -249,9 +244,9 @@ _copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len) if (copy > len) copy = len; - vto = kmap_atomic(*pgto, KM_USER0); + vto = kmap_atomic(*pgto); memcpy(vto + pgbase, p, copy); - kunmap_atomic(vto, KM_USER0); + kunmap_atomic(vto); len -= copy; if (len == 0) @@ -268,7 +263,7 @@ _copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len) flush_dcache_page(*pgto); } -/* +/** * _copy_from_pages * @p: pointer to destination * @pages: array of pages @@ -278,7 +273,7 @@ _copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len) * Copies data into an arbitrary memory location from an array of pages * The copy is assumed to be non-overlapping. */ -static void +void _copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len) { struct page **pgfrom; @@ -293,9 +288,9 @@ _copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len) if (copy > len) copy = len; - vfrom = kmap_atomic(*pgfrom, KM_USER0); + vfrom = kmap_atomic(*pgfrom); memcpy(p, vfrom + pgbase, copy); - kunmap_atomic(vfrom, KM_USER0); + kunmap_atomic(vfrom); pgbase += copy; if (pgbase == PAGE_CACHE_SIZE) { @@ -306,8 +301,9 @@ _copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len) } while ((len -= copy) != 0); } +EXPORT_SYMBOL_GPL(_copy_from_pages); -/* +/** * xdr_shrink_bufhead * @buf: xdr_buf * @len: bytes to remove from buf->head[0] @@ -325,7 +321,10 @@ xdr_shrink_bufhead(struct xdr_buf *buf, size_t len) tail = buf->tail; head = buf->head; - BUG_ON (len > head->iov_len); + + WARN_ON_ONCE(len > head->iov_len); + if (len > head->iov_len) + len = head->iov_len; /* Shift the tail first */ if (tail->iov_len != 0) { @@ -380,7 +379,7 @@ xdr_shrink_bufhead(struct xdr_buf *buf, size_t len) buf->len = buf->buflen; } -/* +/** * xdr_shrink_pagelen * @buf: xdr_buf * @len: bytes to remove from buf->pages @@ -394,24 +393,29 @@ xdr_shrink_pagelen(struct xdr_buf *buf, size_t len) { struct kvec *tail; size_t copy; - char *p; unsigned int pglen = buf->page_len; + unsigned int tailbuf_len; tail = buf->tail; BUG_ON (len > pglen); + tailbuf_len = buf->buflen - buf->head->iov_len - buf->page_len; + /* Shift the tail first */ - if (tail->iov_len != 0) { - p = (char *)tail->iov_base + len; + if (tailbuf_len != 0) { + unsigned int free_space = tailbuf_len - tail->iov_len; + + if (len < free_space) + free_space = len; + tail->iov_len += free_space; + + copy = len; if (tail->iov_len > len) { - copy = tail->iov_len - len; - memmove(p, tail->iov_base, copy); + char *p = (char *)tail->iov_base + len; + memmove(p, tail->iov_base, tail->iov_len - len); } else - buf->buflen -= len; - /* Copy from the inlined pages into the tail */ - copy = len; - if (copy > tail->iov_len) copy = tail->iov_len; + /* Copy from the inlined pages into the tail */ _copy_from_pages((char *)tail->iov_base, buf->pages, buf->page_base + pglen - len, copy); @@ -431,6 +435,16 @@ xdr_shift_buf(struct xdr_buf *buf, size_t len) EXPORT_SYMBOL_GPL(xdr_shift_buf); /** + * xdr_stream_pos - Return the current offset from the start of the xdr_stream + * @xdr: pointer to struct xdr_stream + */ +unsigned int xdr_stream_pos(const struct xdr_stream *xdr) +{ + return (unsigned int)(XDR_QUADLEN(xdr->buf->len) - xdr->nwords) << 2; +} +EXPORT_SYMBOL_GPL(xdr_stream_pos); + +/** * xdr_init_encode - Initialize a struct xdr_stream for sending data. * @xdr: pointer to xdr_stream struct * @buf: pointer to XDR buffer in which to encode data @@ -448,6 +462,7 @@ void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p) struct kvec *iov = buf->head; int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len; + xdr_set_scratch_buffer(xdr, NULL, 0); BUG_ON(scratch_len < 0); xdr->buf = buf; xdr->iov = iov; @@ -468,6 +483,73 @@ void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p) EXPORT_SYMBOL_GPL(xdr_init_encode); /** + * xdr_commit_encode - Ensure all data is written to buffer + * @xdr: pointer to xdr_stream + * + * We handle encoding across page boundaries by giving the caller a + * temporary location to write to, then later copying the data into + * place; xdr_commit_encode does that copying. + * + * Normally the caller doesn't need to call this directly, as the + * following xdr_reserve_space will do it. But an explicit call may be + * required at the end of encoding, or any other time when the xdr_buf + * data might be read. + */ +void xdr_commit_encode(struct xdr_stream *xdr) +{ + int shift = xdr->scratch.iov_len; + void *page; + + if (shift == 0) + return; + page = page_address(*xdr->page_ptr); + memcpy(xdr->scratch.iov_base, page, shift); + memmove(page, page + shift, (void *)xdr->p - page); + xdr->scratch.iov_len = 0; +} +EXPORT_SYMBOL_GPL(xdr_commit_encode); + +__be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr, size_t nbytes) +{ + static __be32 *p; + int space_left; + int frag1bytes, frag2bytes; + + if (nbytes > PAGE_SIZE) + return NULL; /* Bigger buffers require special handling */ + if (xdr->buf->len + nbytes > xdr->buf->buflen) + return NULL; /* Sorry, we're totally out of space */ + frag1bytes = (xdr->end - xdr->p) << 2; + frag2bytes = nbytes - frag1bytes; + if (xdr->iov) + xdr->iov->iov_len += frag1bytes; + else + xdr->buf->page_len += frag1bytes; + xdr->page_ptr++; + xdr->iov = NULL; + /* + * If the last encode didn't end exactly on a page boundary, the + * next one will straddle boundaries. Encode into the next + * page, then copy it back later in xdr_commit_encode. We use + * the "scratch" iov to track any temporarily unused fragment of + * space at the end of the previous buffer: + */ + xdr->scratch.iov_base = xdr->p; + xdr->scratch.iov_len = frag1bytes; + p = page_address(*xdr->page_ptr); + /* + * Note this is where the next encode will start after we've + * shifted this one back: + */ + xdr->p = (void *)p + frag2bytes; + space_left = xdr->buf->buflen - xdr->buf->len; + xdr->end = (void *)p + min_t(int, space_left, PAGE_SIZE); + xdr->buf->page_len += frag2bytes; + xdr->buf->len += nbytes; + return p; +} + +/** * xdr_reserve_space - Reserve buffer space for sending * @xdr: pointer to xdr_stream * @nbytes: number of bytes to reserve @@ -481,20 +563,122 @@ __be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes) __be32 *p = xdr->p; __be32 *q; + xdr_commit_encode(xdr); /* align nbytes on the next 32-bit boundary */ nbytes += 3; nbytes &= ~3; q = p + (nbytes >> 2); if (unlikely(q > xdr->end || q < p)) - return NULL; + return xdr_get_next_encode_buffer(xdr, nbytes); xdr->p = q; - xdr->iov->iov_len += nbytes; + if (xdr->iov) + xdr->iov->iov_len += nbytes; + else + xdr->buf->page_len += nbytes; xdr->buf->len += nbytes; return p; } EXPORT_SYMBOL_GPL(xdr_reserve_space); /** + * xdr_truncate_encode - truncate an encode buffer + * @xdr: pointer to xdr_stream + * @len: new length of buffer + * + * Truncates the xdr stream, so that xdr->buf->len == len, + * and xdr->p points at offset len from the start of the buffer, and + * head, tail, and page lengths are adjusted to correspond. + * + * If this means moving xdr->p to a different buffer, we assume that + * that the end pointer should be set to the end of the current page, + * except in the case of the head buffer when we assume the head + * buffer's current length represents the end of the available buffer. + * + * This is *not* safe to use on a buffer that already has inlined page + * cache pages (as in a zero-copy server read reply), except for the + * simple case of truncating from one position in the tail to another. + * + */ +void xdr_truncate_encode(struct xdr_stream *xdr, size_t len) +{ + struct xdr_buf *buf = xdr->buf; + struct kvec *head = buf->head; + struct kvec *tail = buf->tail; + int fraglen; + int new, old; + + if (len > buf->len) { + WARN_ON_ONCE(1); + return; + } + xdr_commit_encode(xdr); + + fraglen = min_t(int, buf->len - len, tail->iov_len); + tail->iov_len -= fraglen; + buf->len -= fraglen; + if (tail->iov_len && buf->len == len) { + xdr->p = tail->iov_base + tail->iov_len; + /* xdr->end, xdr->iov should be set already */ + return; + } + WARN_ON_ONCE(fraglen); + fraglen = min_t(int, buf->len - len, buf->page_len); + buf->page_len -= fraglen; + buf->len -= fraglen; + + new = buf->page_base + buf->page_len; + old = new + fraglen; + xdr->page_ptr -= (old >> PAGE_SHIFT) - (new >> PAGE_SHIFT); + + if (buf->page_len && buf->len == len) { + xdr->p = page_address(*xdr->page_ptr); + xdr->end = (void *)xdr->p + PAGE_SIZE; + xdr->p = (void *)xdr->p + (new % PAGE_SIZE); + /* xdr->iov should already be NULL */ + return; + } + if (fraglen) { + xdr->end = head->iov_base + head->iov_len; + xdr->page_ptr--; + } + /* (otherwise assume xdr->end is already set) */ + head->iov_len = len; + buf->len = len; + xdr->p = head->iov_base + head->iov_len; + xdr->iov = buf->head; +} +EXPORT_SYMBOL(xdr_truncate_encode); + +/** + * xdr_restrict_buflen - decrease available buffer space + * @xdr: pointer to xdr_stream + * @newbuflen: new maximum number of bytes available + * + * Adjust our idea of how much space is available in the buffer. + * If we've already used too much space in the buffer, returns -1. + * If the available space is already smaller than newbuflen, returns 0 + * and does nothing. Otherwise, adjusts xdr->buf->buflen to newbuflen + * and ensures xdr->end is set at most offset newbuflen from the start + * of the buffer. + */ +int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen) +{ + struct xdr_buf *buf = xdr->buf; + int left_in_this_buf = (void *)xdr->end - (void *)xdr->p; + int end_offset = buf->len + left_in_this_buf; + + if (newbuflen < 0 || newbuflen < buf->len) + return -1; + if (newbuflen > buf->buflen) + return 0; + if (newbuflen < end_offset) + xdr->end = (void *)xdr->end + newbuflen - end_offset; + buf->buflen = newbuflen; + return 0; +} +EXPORT_SYMBOL(xdr_restrict_buflen); + +/** * xdr_write_pages - Insert a list of pages into an XDR buffer for sending * @xdr: pointer to xdr_stream * @pages: list of pages @@ -529,6 +713,72 @@ void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int b } EXPORT_SYMBOL_GPL(xdr_write_pages); +static void xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov, + unsigned int len) +{ + if (len > iov->iov_len) + len = iov->iov_len; + xdr->p = (__be32*)iov->iov_base; + xdr->end = (__be32*)(iov->iov_base + len); + xdr->iov = iov; + xdr->page_ptr = NULL; +} + +static int xdr_set_page_base(struct xdr_stream *xdr, + unsigned int base, unsigned int len) +{ + unsigned int pgnr; + unsigned int maxlen; + unsigned int pgoff; + unsigned int pgend; + void *kaddr; + + maxlen = xdr->buf->page_len; + if (base >= maxlen) + return -EINVAL; + maxlen -= base; + if (len > maxlen) + len = maxlen; + + base += xdr->buf->page_base; + + pgnr = base >> PAGE_SHIFT; + xdr->page_ptr = &xdr->buf->pages[pgnr]; + kaddr = page_address(*xdr->page_ptr); + + pgoff = base & ~PAGE_MASK; + xdr->p = (__be32*)(kaddr + pgoff); + + pgend = pgoff + len; + if (pgend > PAGE_SIZE) + pgend = PAGE_SIZE; + xdr->end = (__be32*)(kaddr + pgend); + xdr->iov = NULL; + return 0; +} + +static void xdr_set_next_page(struct xdr_stream *xdr) +{ + unsigned int newbase; + + newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT; + newbase -= xdr->buf->page_base; + + if (xdr_set_page_base(xdr, newbase, PAGE_SIZE) < 0) + xdr_set_iov(xdr, xdr->buf->tail, xdr->buf->len); +} + +static bool xdr_set_next_buffer(struct xdr_stream *xdr) +{ + if (xdr->page_ptr != NULL) + xdr_set_next_page(xdr); + else if (xdr->iov == xdr->buf->head) { + if (xdr_set_page_base(xdr, 0, PAGE_SIZE) < 0) + xdr_set_iov(xdr, xdr->buf->tail, xdr->buf->len); + } + return xdr->p != xdr->end; +} + /** * xdr_init_decode - Initialize an xdr_stream for decoding data. * @xdr: pointer to xdr_stream struct @@ -537,20 +787,93 @@ EXPORT_SYMBOL_GPL(xdr_write_pages); */ void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p) { - struct kvec *iov = buf->head; - unsigned int len = iov->iov_len; - - if (len > buf->len) - len = buf->len; xdr->buf = buf; - xdr->iov = iov; - xdr->p = p; - xdr->end = (__be32 *)((char *)iov->iov_base + len); + xdr->scratch.iov_base = NULL; + xdr->scratch.iov_len = 0; + xdr->nwords = XDR_QUADLEN(buf->len); + if (buf->head[0].iov_len != 0) + xdr_set_iov(xdr, buf->head, buf->len); + else if (buf->page_len != 0) + xdr_set_page_base(xdr, 0, buf->len); + if (p != NULL && p > xdr->p && xdr->end >= p) { + xdr->nwords -= p - xdr->p; + xdr->p = p; + } } EXPORT_SYMBOL_GPL(xdr_init_decode); /** - * xdr_inline_decode - Retrieve non-page XDR data to decode + * xdr_init_decode - Initialize an xdr_stream for decoding data. + * @xdr: pointer to xdr_stream struct + * @buf: pointer to XDR buffer from which to decode data + * @pages: list of pages to decode into + * @len: length in bytes of buffer in pages + */ +void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf, + struct page **pages, unsigned int len) +{ + memset(buf, 0, sizeof(*buf)); + buf->pages = pages; + buf->page_len = len; + buf->buflen = len; + buf->len = len; + xdr_init_decode(xdr, buf, NULL); +} +EXPORT_SYMBOL_GPL(xdr_init_decode_pages); + +static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes) +{ + unsigned int nwords = XDR_QUADLEN(nbytes); + __be32 *p = xdr->p; + __be32 *q = p + nwords; + + if (unlikely(nwords > xdr->nwords || q > xdr->end || q < p)) + return NULL; + xdr->p = q; + xdr->nwords -= nwords; + return p; +} + +/** + * xdr_set_scratch_buffer - Attach a scratch buffer for decoding data. + * @xdr: pointer to xdr_stream struct + * @buf: pointer to an empty buffer + * @buflen: size of 'buf' + * + * The scratch buffer is used when decoding from an array of pages. + * If an xdr_inline_decode() call spans across page boundaries, then + * we copy the data into the scratch buffer in order to allow linear + * access. + */ +void xdr_set_scratch_buffer(struct xdr_stream *xdr, void *buf, size_t buflen) +{ + xdr->scratch.iov_base = buf; + xdr->scratch.iov_len = buflen; +} +EXPORT_SYMBOL_GPL(xdr_set_scratch_buffer); + +static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes) +{ + __be32 *p; + void *cpdest = xdr->scratch.iov_base; + size_t cplen = (char *)xdr->end - (char *)xdr->p; + + if (nbytes > xdr->scratch.iov_len) + return NULL; + memcpy(cpdest, xdr->p, cplen); + cpdest += cplen; + nbytes -= cplen; + if (!xdr_set_next_buffer(xdr)) + return NULL; + p = __xdr_inline_decode(xdr, nbytes); + if (p == NULL) + return NULL; + memcpy(cpdest, p, nbytes); + return xdr->scratch.iov_base; +} + +/** + * xdr_inline_decode - Retrieve XDR data to decode * @xdr: pointer to xdr_stream struct * @nbytes: number of bytes of data to decode * @@ -561,16 +884,49 @@ EXPORT_SYMBOL_GPL(xdr_init_decode); */ __be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes) { - __be32 *p = xdr->p; - __be32 *q = p + XDR_QUADLEN(nbytes); + __be32 *p; - if (unlikely(q > xdr->end || q < p)) + if (nbytes == 0) + return xdr->p; + if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr)) return NULL; - xdr->p = q; - return p; + p = __xdr_inline_decode(xdr, nbytes); + if (p != NULL) + return p; + return xdr_copy_to_scratch(xdr, nbytes); } EXPORT_SYMBOL_GPL(xdr_inline_decode); +static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len) +{ + struct xdr_buf *buf = xdr->buf; + struct kvec *iov; + unsigned int nwords = XDR_QUADLEN(len); + unsigned int cur = xdr_stream_pos(xdr); + + if (xdr->nwords == 0) + return 0; + /* Realign pages to current pointer position */ + iov = buf->head; + if (iov->iov_len > cur) { + xdr_shrink_bufhead(buf, iov->iov_len - cur); + xdr->nwords = XDR_QUADLEN(buf->len - cur); + } + + if (nwords > xdr->nwords) { + nwords = xdr->nwords; + len = nwords << 2; + } + if (buf->page_len <= len) + len = buf->page_len; + else if (nwords < xdr->nwords) { + /* Truncate page data and move it into the tail */ + xdr_shrink_pagelen(buf, buf->page_len - len); + xdr->nwords = XDR_QUADLEN(buf->len - cur); + } + return len; +} + /** * xdr_read_pages - Ensure page-based XDR data to decode is aligned at current pointer position * @xdr: pointer to xdr_stream struct @@ -579,39 +935,37 @@ EXPORT_SYMBOL_GPL(xdr_inline_decode); * Moves data beyond the current pointer position from the XDR head[] buffer * into the page list. Any data that lies beyond current position + "len" * bytes is moved into the XDR tail[]. + * + * Returns the number of XDR encoded bytes now contained in the pages */ -void xdr_read_pages(struct xdr_stream *xdr, unsigned int len) +unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len) { struct xdr_buf *buf = xdr->buf; struct kvec *iov; - ssize_t shift; + unsigned int nwords; unsigned int end; - int padding; - - /* Realign pages to current pointer position */ - iov = buf->head; - shift = iov->iov_len + (char *)iov->iov_base - (char *)xdr->p; - if (shift > 0) - xdr_shrink_bufhead(buf, shift); + unsigned int padding; - /* Truncate page data and move it into the tail */ - if (buf->page_len > len) - xdr_shrink_pagelen(buf, buf->page_len - len); - padding = (XDR_QUADLEN(len) << 2) - len; + len = xdr_align_pages(xdr, len); + if (len == 0) + return 0; + nwords = XDR_QUADLEN(len); + padding = (nwords << 2) - len; xdr->iov = iov = buf->tail; /* Compute remaining message length. */ - end = iov->iov_len; - shift = buf->buflen - buf->len; - if (shift < end) - end -= shift; - else if (shift > 0) - end = 0; + end = ((xdr->nwords - nwords) << 2) + padding; + if (end > iov->iov_len) + end = iov->iov_len; + /* * Position current pointer at beginning of tail, and * set remaining message length. */ xdr->p = (__be32 *)((char *)iov->iov_base + padding); xdr->end = (__be32 *)((char *)iov->iov_base + end); + xdr->page_ptr = NULL; + xdr->nwords = XDR_QUADLEN(end - padding); + return len; } EXPORT_SYMBOL_GPL(xdr_read_pages); @@ -627,16 +981,13 @@ EXPORT_SYMBOL_GPL(xdr_read_pages); */ void xdr_enter_page(struct xdr_stream *xdr, unsigned int len) { - char * kaddr = page_address(xdr->buf->pages[0]); - xdr_read_pages(xdr, len); + len = xdr_align_pages(xdr, len); /* * Position current pointer at beginning of tail, and * set remaining message length. */ - if (len > PAGE_CACHE_SIZE - xdr->buf->page_base) - len = PAGE_CACHE_SIZE - xdr->buf->page_base; - xdr->p = (__be32 *)(kaddr + xdr->buf->page_base); - xdr->end = (__be32 *)((char *)xdr->p + len); + if (len != 0) + xdr_set_page_base(xdr, 0, len); } EXPORT_SYMBOL_GPL(xdr_enter_page); @@ -652,8 +1003,20 @@ xdr_buf_from_iov(struct kvec *iov, struct xdr_buf *buf) } EXPORT_SYMBOL_GPL(xdr_buf_from_iov); -/* Sets subbuf to the portion of buf of length len beginning base bytes - * from the start of buf. Returns -1 if base of length are out of bounds. */ +/** + * xdr_buf_subsegment - set subbuf to a portion of buf + * @buf: an xdr buffer + * @subbuf: the result buffer + * @base: beginning of range in bytes + * @len: length of range in bytes + * + * sets @subbuf to an xdr buffer representing the portion of @buf of + * length @len starting at offset @base. + * + * @buf and @subbuf may be pointers to the same struct xdr_buf. + * + * Returns -1 if base of length are out of bounds. + */ int xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf, unsigned int base, unsigned int len) @@ -666,9 +1029,8 @@ xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf, len -= subbuf->head[0].iov_len; base = 0; } else { - subbuf->head[0].iov_base = NULL; - subbuf->head[0].iov_len = 0; base -= buf->head[0].iov_len; + subbuf->head[0].iov_len = 0; } if (base < buf->page_len) { @@ -690,9 +1052,8 @@ xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf, len -= subbuf->tail[0].iov_len; base = 0; } else { - subbuf->tail[0].iov_base = NULL; - subbuf->tail[0].iov_len = 0; base -= buf->tail[0].iov_len; + subbuf->tail[0].iov_len = 0; } if (base || len) @@ -701,6 +1062,47 @@ xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf, } EXPORT_SYMBOL_GPL(xdr_buf_subsegment); +/** + * xdr_buf_trim - lop at most "len" bytes off the end of "buf" + * @buf: buf to be trimmed + * @len: number of bytes to reduce "buf" by + * + * Trim an xdr_buf by the given number of bytes by fixing up the lengths. Note + * that it's possible that we'll trim less than that amount if the xdr_buf is + * too small, or if (for instance) it's all in the head and the parser has + * already read too far into it. + */ +void xdr_buf_trim(struct xdr_buf *buf, unsigned int len) +{ + size_t cur; + unsigned int trim = len; + + if (buf->tail[0].iov_len) { + cur = min_t(size_t, buf->tail[0].iov_len, trim); + buf->tail[0].iov_len -= cur; + trim -= cur; + if (!trim) + goto fix_len; + } + + if (buf->page_len) { + cur = min_t(unsigned int, buf->page_len, trim); + buf->page_len -= cur; + trim -= cur; + if (!trim) + goto fix_len; + } + + if (buf->head[0].iov_len) { + cur = min_t(size_t, buf->head[0].iov_len, trim); + buf->head[0].iov_len -= cur; + trim -= cur; + } +fix_len: + buf->len -= (len - trim); +} +EXPORT_SYMBOL_GPL(xdr_buf_trim); + static void __read_bytes_from_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len) { unsigned int this_len; @@ -761,6 +1163,7 @@ int write_bytes_to_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, un __write_bytes_to_xdr_buf(&subbuf, obj, len); return 0; } +EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf); int xdr_decode_word(struct xdr_buf *buf, unsigned int base, u32 *obj) @@ -1046,7 +1449,7 @@ xdr_process_buf(struct xdr_buf *buf, unsigned int offset, unsigned int len, int (*actor)(struct scatterlist *, void *), void *data) { int i, ret = 0; - unsigned page_len, thislen, page_offset; + unsigned int page_len, thislen, page_offset; struct scatterlist sg[1]; sg_init_table(sg, 1); |