[PATCH] RPC: Ensure XDR iovec length is initialized correctly in call_header

 Fix up call_header() so that it calls xdr_adjust_iovec().
 Fix calculation of the scratch buffer length in xdr_init_encode().
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

net/sunrpc/clnt.c

@@ -957,7 +957,9 @@ call_header(struct rpc_task *task)
 	*p++ = htonl(clnt->cl_prog);	/* program number */
 	*p++ = htonl(clnt->cl_vers);	/* program version */
 	*p++ = htonl(task->tk_msg.rpc_proc->p_proc);	/* procedure */
-	return rpcauth_marshcred(task, p);
+	p = rpcauth_marshcred(task, p);
+	req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
+	return p;
 }
 
 /*

net/sunrpc/svc.c

@@ -281,6 +281,7 @@ svc_process(struct svc_serv *serv, struct svc_rqst *rqstp)
 	rqstp->rq_res.len = 0;
 	rqstp->rq_res.page_base = 0;
 	rqstp->rq_res.page_len = 0;
+	rqstp->rq_res.buflen = PAGE_SIZE;
 	rqstp->rq_res.tail[0].iov_len = 0;
 	/* tcp needs a space for the record length... */
 	if (rqstp->rq_prot == IPPROTO_TCP)

net/sunrpc/xdr.c

@@ -616,12 +616,24 @@ xdr_shift_buf(struct xdr_buf *buf, size_t len)
 void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, uint32_t *p)
 {
 	struct kvec *iov = buf->head;
+	int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len;
 
+	BUG_ON(scratch_len < 0);
 	xdr->buf = buf;
 	xdr->iov = iov;
-	xdr->end = (uint32_t *)((char *)iov->iov_base + iov->iov_len);
-	buf->len = iov->iov_len = (char *)p - (char *)iov->iov_base;
-	xdr->p = p;
+	xdr->p = (uint32_t *)((char *)iov->iov_base + iov->iov_len);
+	xdr->end = (uint32_t *)((char *)iov->iov_base + scratch_len);
+	BUG_ON(iov->iov_len > scratch_len);
+
+	if (p != xdr->p && p != NULL) {
+		size_t len;
+
+		BUG_ON(p < xdr->p || p > xdr->end);
+		len = (char *)p - (char *)xdr->p;
+		xdr->p = p;
+		buf->len += len;
+		iov->iov_len += len;
+	}
 }
 EXPORT_SYMBOL(xdr_init_encode);