rxrpc: checking for IS_ERR() instead of NULL

rxrpc_lookup_peer_rcu() and rxrpc_lookup_peer() return NULL on error, never
error pointers, so IS_ERR() can't be used.

Fix three callers of those functions.

Fixes: be6e6707f6ee ('rxrpc: Rework peer object handling to use hash table and RCU')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>

net/rxrpc/af_rxrpc.c

@@ -247,8 +247,8 @@ struct rxrpc_transport *rxrpc_name_to_transport(struct rxrpc_sock *rx,
 
 	/* find a remote transport endpoint from the local one */
 	peer = rxrpc_lookup_peer(rx->local, srx, gfp);
-	if (IS_ERR(peer))
-		return ERR_CAST(peer);
+	if (!peer)
+		return ERR_PTR(-ENOMEM);
 
 	/* find a transport */
 	trans = rxrpc_get_transport(rx->local, peer, gfp);

net/rxrpc/call_accept.c

@@ -96,7 +96,7 @@ static int rxrpc_accept_incoming_call(struct rxrpc_local *local,
 	notification->mark = RXRPC_SKB_MARK_NEW_CALL;
 
 	peer = rxrpc_lookup_peer(local, srx, GFP_NOIO);
-	if (IS_ERR(peer)) {
+	if (!peer) {
 		_debug("no peer");
 		ret = -EBUSY;
 		goto error;

net/rxrpc/input.c

@@ -639,7 +639,7 @@ static struct rxrpc_connection *rxrpc_conn_from_local(struct rxrpc_local *local,
 	rxrpc_get_addr_from_skb(local, skb, &srx);
 	rcu_read_lock();
 	peer = rxrpc_lookup_peer_rcu(local, &srx);
-	if (IS_ERR(peer))
+	if (!peer)
 		goto cant_find_peer;
 
 	trans = rxrpc_find_transport(local, peer);