[PATCH v13 46/51] sunrpc: Add xdr_init_encode_pages

Andreas Gruenbacher
2015-11-03T15:22:59Z

Initialize xdr_stream and xdr_buf from a pages array, for encoding into
the pages.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
include/linux/sunrpc/xdr.h | 2 ++
net/sunrpc/xdr.c | 25 +++++++++++++++++++++++++
2 files changed, 27 insertions(+)

diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h
index 70c6b92..2c99cff 100644
--- a/include/linux/sunrpc/xdr.h
+++ b/include/linux/sunrpc/xdr.h
@@ -214,6 +214,8 @@ typedef void (*kxdreproc_t)(void *rqstp, struct xdr_stream *xdr, void *obj);
typedef int (*kxdrdproc_t)(void *rqstp, struct xdr_stream *xdr, void *obj);

extern void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p);
+extern void xdr_init_encode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
+ struct page **pages, unsigned int len);
extern __be32 *xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes);
extern void xdr_commit_encode(struct xdr_stream *xdr);
extern void xdr_truncate_encode(struct xdr_stream *xdr, size_t len);
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index 63c1c36..f97b96b 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -483,6 +483,31 @@ void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
EXPORT_SYMBOL_GPL(xdr_init_encode);

/**
+ * xdr_init_encode_pages - Initialize struct xdr_stream for encoding into pages
+ * @xdr: pointer to xdr_stream struct
+ * @buf: pointer to XDR buffer in which to encode data
+ * @pages: pages array in which to encode
+ * @len: maximum length of @buf
+ *
+ * Initialize @xdr and @buf for encoding into the @pages array. If a
+ * page in @pages is NULL, it will be allocated on demand.
+ */
+void xdr_init_encode_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;
+
+ memset(xdr, 0, sizeof(*xdr));
+ xdr->buf = buf;
+ xdr->iov = buf->head;
+ xdr->page_ptr = pages - 1;
+}
+EXPORT_SYMBOL_GPL(xdr_init_encode_pages);
+
+/**
* xdr_commit_encode - Ensure all data is written to buffer
* @xdr: pointer to xdr_stream
*