NFSD: Clean up nfsd4_encode_readv

Address some minor nits I noticed while working on this function.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/nfsd/nfs4xdr.c

@@ -3591,7 +3591,6 @@ static __be32 nfsd4_encode_readv(struct nfsd4_compoundres *resp,
 	__be32 nfserr;
 	__be32 tmp;
 	__be32 *p;
-	u32 zzz = 0;
 	int pad;
 
 	/*
@@ -3607,7 +3606,7 @@ static __be32 nfsd4_encode_readv(struct nfsd4_compoundres *resp,
 	v = 0;
 	while (len) {
 		thislen = min_t(long, len, PAGE_SIZE);
-		p = xdr_reserve_space(xdr, (thislen+3)&~3);
+		p = xdr_reserve_space(xdr, thislen);
 		WARN_ON_ONCE(!p);
 		resp->rqstp->rq_vec[v].iov_base = p;
 		resp->rqstp->rq_vec[v].iov_len = thislen;
@@ -3616,7 +3615,6 @@ static __be32 nfsd4_encode_readv(struct nfsd4_compoundres *resp,
 	}
 	read->rd_vlen = v;
 
-	len = maxcount;
 	nfserr = nfsd_readv(resp->rqstp, read->rd_fhp, file, read->rd_offset,
 			    resp->rqstp->rq_vec, read->rd_vlen, &maxcount,
 			    &eof);
@@ -3625,16 +3623,17 @@ static __be32 nfsd4_encode_readv(struct nfsd4_compoundres *resp,
 		return nfserr;
 	if (svc_encode_read_payload(resp->rqstp, starting_len + 8, maxcount))
 		return nfserr_io;
-	xdr_truncate_encode(xdr, starting_len + 8 + ((maxcount+3)&~3));
+	xdr_truncate_encode(xdr, starting_len + 8 + xdr_align_size(maxcount));
 
 	tmp = htonl(eof);
 	write_bytes_to_xdr_buf(xdr->buf, starting_len    , &tmp, 4);
 	tmp = htonl(maxcount);
 	write_bytes_to_xdr_buf(xdr->buf, starting_len + 4, &tmp, 4);
 
+	tmp = xdr_zero;
 	pad = (maxcount&3) ? 4 - (maxcount&3) : 0;
 	write_bytes_to_xdr_buf(xdr->buf, starting_len + 8 + maxcount,
-								&zzz, pad);
+								&tmp, pad);
 	return 0;
 
 }