rpc: move process_xdr_buf

Since process_xdr_buf() is useful outside of the kerberos-specific code, we
move it to net/sunrpc/xdr.c, export it, and rename it in keeping with xdr_*
naming convention of xdr.c.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h
index 441b91d..4d17846 100644
--- a/include/linux/sunrpc/xdr.h
+++ b/include/linux/sunrpc/xdr.h
@@ -11,6 +11,7 @@
 
 #include <linux/uio.h>
 #include <asm/byteorder.h>
+#include <linux/scatterlist.h>
 
 /*
  * Buffer adjustment
@@ -196,6 +197,7 @@
 extern __be32 *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);
+extern int xdr_process_buf(struct xdr_buf *buf, unsigned int offset, unsigned int len, int (*actor)(struct scatterlist *, void *), void *data);
 
 #endif /* __KERNEL__ */