pNFS: Clean up open coded xdr string decoding

Use the existing xdr_stream_decode_string_dup() to safely decode into
kmalloced strings.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/pnfs_nfs.c

@@ -1045,9 +1045,8 @@ nfs4_decode_mp_ds_addr(struct net *net, struct xdr_stream *xdr, gfp_t gfp_flags)
 	struct nfs4_pnfs_ds_addr *da = NULL;
 	char *buf, *portstr;
 	__be16 port;
-	int nlen, rlen;
+	ssize_t nlen, rlen;
 	int tmp[2];
-	__be32 *p;
 	char *netid;
 	size_t len;
 	char *startsep = "";
@@ -1055,45 +1054,17 @@ nfs4_decode_mp_ds_addr(struct net *net, struct xdr_stream *xdr, gfp_t gfp_flags)
 
 
 	/* r_netid */
-	p = xdr_inline_decode(xdr, 4);
-	if (unlikely(!p))
+	nlen = xdr_stream_decode_string_dup(xdr, &netid, XDR_MAX_NETOBJ,
+					    gfp_flags);
+	if (unlikely(nlen < 0))
 		goto out_err;
-	nlen = be32_to_cpup(p++);
-
-	p = xdr_inline_decode(xdr, nlen);
-	if (unlikely(!p))
-		goto out_err;
-
-	netid = kmalloc(nlen+1, gfp_flags);
-	if (unlikely(!netid))
-		goto out_err;
-
-	netid[nlen] = '\0';
-	memcpy(netid, p, nlen);
 
 	/* r_addr: ip/ip6addr with port in dec octets - see RFC 5665 */
-	p = xdr_inline_decode(xdr, 4);
-	if (unlikely(!p))
-		goto out_free_netid;
-	rlen = be32_to_cpup(p);
-
-	p = xdr_inline_decode(xdr, rlen);
-	if (unlikely(!p))
-		goto out_free_netid;
-
 	/* port is ".ABC.DEF", 8 chars max */
-	if (rlen > INET6_ADDRSTRLEN + IPV6_SCOPE_ID_LEN + 8) {
-		dprintk("%s: Invalid address, length %d\n", __func__,
-			rlen);
+	rlen = xdr_stream_decode_string_dup(xdr, &buf, INET6_ADDRSTRLEN +
+					    IPV6_SCOPE_ID_LEN + 8, gfp_flags);
+	if (unlikely(rlen < 0))
 		goto out_free_netid;
-	}
-	buf = kmalloc(rlen + 1, gfp_flags);
-	if (!buf) {
-		dprintk("%s: Not enough memory\n", __func__);
-		goto out_free_netid;
-	}
-	buf[rlen] = '\0';
-	memcpy(buf, p, rlen);
 
 	/* replace port '.' with '-' */
 	portstr = strrchr(buf, '.');