diff options
| -rw-r--r-- | include/linux/sunrpc/xdr.h | 2 | ||||
| -rw-r--r-- | net/sunrpc/xdr.c | 59 |
2 files changed, 61 insertions, 0 deletions
diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h index 5860f32e3958..7dcc6c31fe29 100644 --- a/include/linux/sunrpc/xdr.h +++ b/include/linux/sunrpc/xdr.h @@ -262,6 +262,8 @@ extern unsigned int xdr_align_data(struct xdr_stream *, unsigned int offset, uns extern unsigned int xdr_expand_hole(struct xdr_stream *, unsigned int offset, unsigned int length); extern bool xdr_stream_subsegment(struct xdr_stream *xdr, struct xdr_buf *subbuf, unsigned int len); +extern unsigned int xdr_stream_move_subsegment(struct xdr_stream *xdr, unsigned int offset, + unsigned int target, unsigned int length); /** * xdr_set_scratch_buffer - Attach a scratch buffer for decoding data. diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c index 5d2b3e6979fb..8ba11a754297 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 @@ -1681,6 +1709,37 @@ 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_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 |