diff options
Diffstat (limited to 'net/sunrpc/xdr.c')
-rw-r--r-- | net/sunrpc/xdr.c | 229 |
1 files changed, 153 insertions, 76 deletions
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c index df194cc07035..336a7c7833e4 100644 --- a/net/sunrpc/xdr.c +++ b/net/sunrpc/xdr.c @@ -775,6 +775,34 @@ static void xdr_buf_pages_shift_left(const struct xdr_buf *buf, xdr_buf_tail_copy_left(buf, 0, len - buf->page_len, shift); } +static void xdr_buf_head_shift_left(const struct xdr_buf *buf, + unsigned int base, unsigned int len, + unsigned int shift) +{ + const struct kvec *head = buf->head; + unsigned int bytes; + + if (!shift || !len) + return; + + if (shift > base) { + bytes = (shift - base); + if (bytes >= len) + return; + base += bytes; + len -= bytes; + } + + if (base < head->iov_len) { + bytes = min_t(unsigned int, len, head->iov_len - base); + memmove(head->iov_base + (base - shift), + head->iov_base + base, bytes); + base += bytes; + len -= bytes; + } + xdr_buf_pages_shift_left(buf, base - head->iov_len, len, shift); +} + /** * xdr_shrink_bufhead * @buf: xdr_buf @@ -919,7 +947,29 @@ 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_init_encode_pages - Initialize an xdr_stream for encoding into pages + * @xdr: pointer to xdr_stream struct + * @buf: pointer to XDR buffer into which to encode data + * @pages: list of pages to decode into + * @rqst: pointer to controlling rpc_rqst, for debugging + * + */ +void xdr_init_encode_pages(struct xdr_stream *xdr, struct xdr_buf *buf, + struct page **pages, struct rpc_rqst *rqst) +{ + xdr_reset_scratch_buffer(xdr); + + xdr->buf = buf; + xdr->page_ptr = pages; + xdr->iov = NULL; + xdr->p = page_address(*pages); + xdr->end = (void *)xdr->p + min_t(u32, buf->buflen, PAGE_SIZE); + xdr->rqst = rqst; +} +EXPORT_SYMBOL_GPL(xdr_init_encode_pages); + +/** + * __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 @@ -931,26 +981,29 @@ EXPORT_SYMBOL_GPL(xdr_init_encode); * required at the end of encoding, or any other time when the xdr_buf * data might be read. */ -inline void xdr_commit_encode(struct xdr_stream *xdr) +void __xdr_commit_encode(struct xdr_stream *xdr) { - int shift = xdr->scratch.iov_len; + size_t 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_reset_scratch_buffer(xdr); } -EXPORT_SYMBOL_GPL(xdr_commit_encode); +EXPORT_SYMBOL_GPL(__xdr_commit_encode); -static __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr, - size_t nbytes) +/* + * The buffer space to be reserved crosses the boundary between + * xdr->buf->head and xdr->buf->pages, or between two pages + * in xdr->buf->pages. + */ +static noinline __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr, + size_t nbytes) { - __be32 *p; int space_left; int frag1bytes, frag2bytes; + void *p; if (nbytes > PAGE_SIZE) goto out_overflow; /* Bigger buffers require special handling */ @@ -964,6 +1017,7 @@ static __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr, 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 @@ -972,14 +1026,19 @@ static __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr, * space at the end of the previous buffer: */ xdr_set_scratch_buffer(xdr, xdr->p, 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 is where the next encode will start after + * xdr_commit_encode() has shifted this one back: */ - xdr->p = (void *)p + frag2bytes; + p = page_address(*xdr->page_ptr); + xdr->p = p + frag2bytes; space_left = xdr->buf->buflen - xdr->buf->len; - xdr->end = (void *)p + min_t(int, space_left, PAGE_SIZE); + if (space_left - frag1bytes >= PAGE_SIZE) + xdr->end = p + PAGE_SIZE; + else + xdr->end = p + space_left - frag1bytes; + xdr->buf->page_len += frag2bytes; xdr->buf->len += nbytes; return p; @@ -1463,71 +1522,35 @@ unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len) } EXPORT_SYMBOL_GPL(xdr_read_pages); -unsigned int xdr_align_data(struct xdr_stream *xdr, unsigned int offset, - unsigned int length) -{ - struct xdr_buf *buf = xdr->buf; - unsigned int from, bytes, len; - unsigned int shift; - - xdr_realign_pages(xdr); - from = xdr_page_pos(xdr); - - if (from >= buf->page_len + buf->tail->iov_len) - return 0; - if (from + buf->head->iov_len >= buf->len) - return 0; - - len = buf->len - buf->head->iov_len; - - /* We only shift data left! */ - if (WARN_ONCE(from < offset, "SUNRPC: misaligned data src=%u dst=%u\n", - from, offset)) - return 0; - if (WARN_ONCE(offset > buf->page_len, - "SUNRPC: buffer overflow. offset=%u, page_len=%u\n", - offset, buf->page_len)) - return 0; - - /* Move page data to the left */ - shift = from - offset; - xdr_buf_pages_shift_left(buf, from, len, shift); - - bytes = xdr_stream_remaining(xdr); - if (length > bytes) - length = bytes; - bytes -= length; - - xdr->buf->len -= shift; - xdr_set_page(xdr, offset + length, bytes); - return length; -} -EXPORT_SYMBOL_GPL(xdr_align_data); - -unsigned int xdr_expand_hole(struct xdr_stream *xdr, unsigned int offset, - unsigned int length) +/** + * xdr_set_pagelen - Sets the length of the XDR pages + * @xdr: pointer to xdr_stream struct + * @len: new length of the XDR page data + * + * Either grows or shrinks the length of the xdr pages by setting pagelen to + * @len bytes. When shrinking, any extra data is moved into buf->tail, whereas + * when growing any data beyond the current pointer is moved into the tail. + * + * Returns True if the operation was successful, and False otherwise. + */ +void xdr_set_pagelen(struct xdr_stream *xdr, unsigned int len) { struct xdr_buf *buf = xdr->buf; - unsigned int from, to, shift; - - xdr_realign_pages(xdr); - from = xdr_page_pos(xdr); - to = xdr_align_size(offset + length); - - /* Could the hole be behind us? */ - if (to > from) { - unsigned int buflen = buf->len - buf->head->iov_len; - shift = to - from; - xdr_buf_try_expand(buf, shift); - xdr_buf_pages_shift_right(buf, from, buflen, shift); - xdr_set_page(xdr, to, xdr_stream_remaining(xdr)); - } else if (to != from) - xdr_align_data(xdr, to, 0); - xdr_buf_pages_zero(buf, offset, length); + size_t remaining = xdr_stream_remaining(xdr); + size_t base = 0; - return length; + if (len < buf->page_len) { + base = buf->page_len - len; + xdr_shrink_pagelen(buf, len); + } else { + xdr_buf_head_shift_right(buf, xdr_stream_pos(xdr), + buf->page_len, remaining); + if (len > buf->page_len) + xdr_buf_try_expand(buf, len - buf->page_len); + } + xdr_set_tail_base(xdr, base, remaining); } -EXPORT_SYMBOL_GPL(xdr_expand_hole); +EXPORT_SYMBOL_GPL(xdr_set_pagelen); /** * xdr_enter_page - decode data from the XDR page @@ -1574,7 +1597,7 @@ EXPORT_SYMBOL_GPL(xdr_buf_from_iov); * * @buf and @subbuf may be pointers to the same struct xdr_buf. * - * Returns -1 if base of length are out of bounds. + * Returns -1 if base or length are out of bounds. */ int xdr_buf_subsegment(const struct xdr_buf *buf, struct xdr_buf *subbuf, unsigned int base, unsigned int len) @@ -1672,6 +1695,60 @@ bool xdr_stream_subsegment(struct xdr_stream *xdr, struct xdr_buf *subbuf, EXPORT_SYMBOL_GPL(xdr_stream_subsegment); /** + * xdr_stream_move_subsegment - Move part of a stream to another position + * @xdr: the source xdr_stream + * @offset: the source offset of the segment + * @target: the target offset of the segment + * @length: the number of bytes to move + * + * Moves @length bytes from @offset to @target in the xdr_stream, overwriting + * anything in its space. Returns the number of bytes in the segment. + */ +unsigned int xdr_stream_move_subsegment(struct xdr_stream *xdr, unsigned int offset, + unsigned int target, unsigned int length) +{ + struct xdr_buf buf; + unsigned int shift; + + if (offset < target) { + shift = target - offset; + if (xdr_buf_subsegment(xdr->buf, &buf, offset, shift + length) < 0) + return 0; + xdr_buf_head_shift_right(&buf, 0, length, shift); + } else if (offset > target) { + shift = offset - target; + if (xdr_buf_subsegment(xdr->buf, &buf, target, shift + length) < 0) + return 0; + xdr_buf_head_shift_left(&buf, shift, length, shift); + } + return length; +} +EXPORT_SYMBOL_GPL(xdr_stream_move_subsegment); + +/** + * xdr_stream_zero - zero out a portion of an xdr_stream + * @xdr: an xdr_stream to zero out + * @offset: the starting point in the stream + * @length: the number of bytes to zero + */ +unsigned int xdr_stream_zero(struct xdr_stream *xdr, unsigned int offset, + unsigned int length) +{ + struct xdr_buf buf; + + if (xdr_buf_subsegment(xdr->buf, &buf, offset, length) < 0) + return 0; + if (buf.head[0].iov_len) + xdr_buf_iov_zero(buf.head, 0, buf.head[0].iov_len); + if (buf.page_len > 0) + xdr_buf_pages_zero(&buf, 0, buf.page_len); + if (buf.tail[0].iov_len) + xdr_buf_iov_zero(buf.tail, 0, buf.tail[0].iov_len); + return length; +} +EXPORT_SYMBOL_GPL(xdr_stream_zero); + +/** * 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 |