[PATCH RFC2 2/3] SUNRPC: Track current encode position in struct xdr_stream

[Chuck Lever <chuck.lever@oracle.com>]

Maintain a byte-offset cursor in struct xdr_stream. This will be
used in a subsequent patch.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/nfsd/nfs4proc.c         |    1 +
 include/linux/sunrpc/xdr.h |    1 +
 net/sunrpc/xdr.c           |    2 ++
 3 files changed, 4 insertions(+)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 4798667af647..9cd610485f7d 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1904,6 +1904,7 @@ static void svcxdr_init_encode(struct svc_rqst *rqstp,
 	xdr->iov = head;
 	xdr->p   = head->iov_base + head->iov_len;
 	xdr->end = head->iov_base + PAGE_SIZE - rqstp->rq_auth_slack;
+	xdr->pos = head->iov_len;
 	/* Tail and page_len should be zero at this point: */
 	buf->len = buf->head[0].iov_len;
 	xdr->scratch.iov_len = 0;
diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h
index b41f34977995..2ca479b0708e 100644
--- a/include/linux/sunrpc/xdr.h
+++ b/include/linux/sunrpc/xdr.h
@@ -232,6 +232,7 @@ struct xdr_stream {
 	struct kvec *iov;	/* pointer to the current kvec */
 	struct kvec scratch;	/* Scratch buffer */
 	struct page **page_ptr;	/* pointer to the current page */
+	unsigned int pos;	/* current encode position */
 	unsigned int nwords;	/* Remaining decode buffer length */
 
 	struct rpc_rqst *rqst;	/* For debugging */
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index f3104be8ff5d..b8b78876a9bd 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -542,6 +542,7 @@ void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
 		buf->len += len;
 		iov->iov_len += len;
 	}
+	xdr->pos = iov->iov_len;
 	xdr->rqst = rqst;
 }
 EXPORT_SYMBOL_GPL(xdr_init_encode);
@@ -644,6 +645,7 @@ __be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
 	else
 		xdr->buf->page_len += nbytes;
 	xdr->buf->len += nbytes;
+	xdr->pos += nbytes;
 	return p;
 }
 EXPORT_SYMBOL_GPL(xdr_reserve_space);