From: Trond Myklebust RPC: Allow struc xdr_stream to read the page section of an xdr_buf Signed-off-by: Trond Myklebust --- include/linux/sunrpc/xdr.h | 1 + net/sunrpc/xdr.c | 28 ++++++++++++++++++++++++++-- 2 files changed, 27 insertions(+), 2 deletions(-) diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h index 84c35d4..e6d3d34 100644 --- a/include/linux/sunrpc/xdr.h +++ b/include/linux/sunrpc/xdr.h @@ -194,6 +194,7 @@ extern void xdr_write_pages(struct xdr_s extern void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, uint32_t *p); extern uint32_t *xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes); extern void xdr_read_pages(struct xdr_stream *xdr, unsigned int len); +extern void xdr_enter_page(struct xdr_stream *xdr, unsigned int len); #endif /* __KERNEL__ */ diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c index ca4bfa5..49174f0 100644 --- a/net/sunrpc/xdr.c +++ b/net/sunrpc/xdr.c @@ -568,8 +568,7 @@ EXPORT_SYMBOL(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[]. The current pointer is then - * repositioned at the beginning of the XDR tail. + * bytes is moved into the XDR tail[]. */ void xdr_read_pages(struct xdr_stream *xdr, unsigned int len) { @@ -606,6 +605,31 @@ void xdr_read_pages(struct xdr_stream *x } EXPORT_SYMBOL(xdr_read_pages); +/** + * xdr_enter_page - decode data from the XDR page + * @xdr: pointer to xdr_stream struct + * @len: number of bytes of page data + * + * 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[]. The current pointer is then + * repositioned at the beginning of the first XDR page. + */ +void xdr_enter_page(struct xdr_stream *xdr, unsigned int len) +{ + char * kaddr = page_address(xdr->buf->pages[0]); + xdr_read_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 = (uint32_t *)(kaddr + xdr->buf->page_base); + xdr->end = (uint32_t *)((char *)xdr->p + len); +} +EXPORT_SYMBOL(xdr_enter_page); + static struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0}; void