+ conn = lustre_hash_lookup(conn_hash, &peer);
+ if (conn)
+ GOTO(out, conn);
+
+ OBD_ALLOC_PTR(conn);
+ if (!conn)
+ RETURN(NULL);
+
+ conn->c_peer = peer;
+ conn->c_self = self;
+ INIT_HLIST_NODE(&conn->c_hash);
+ atomic_set(&conn->c_refcount, 1);
+ if (uuid)
+ obd_str2uuid(&conn->c_remote_uuid, uuid->uuid);
+
+ /*
+ * Add the newly created conn to the hash, on key collision we
+ * lost a racing addition and must destroy our newly allocated
+ * connection. The object which exists in the has will be
+ * returned and may be compared against out object.
+ */
+ conn2 = lustre_hash_findadd_unique(conn_hash, &peer, &conn->c_hash);
+ if (conn != conn2) {
+ OBD_FREE_PTR(conn);
+ conn = conn2;
+ }
+ EXIT;
+out:
+ CDEBUG(D_INFO, "conn=%p refcount %d to %s\n",
+ conn, atomic_read(&conn->c_refcount),
+ libcfs_nid2str(conn->c_peer.nid));
+ return conn;
+}
+
+int ptlrpc_connection_put(struct ptlrpc_connection *conn)
+{
+ int rc = 0;
+ ENTRY;
+
+ if (!conn)
+ RETURN(rc);
+
+ LASSERT(!hlist_unhashed(&conn->c_hash));
+
+ /*
+ * We do not remove connection from hashtable and
+ * do not free it even if last caller released ref,
+ * as we want to have it cached for the case it is
+ * needed again.
+ *
+ * Deallocating it and later creating new connection
+ * again would be wastful. This way we also avoid
+ * expensive locking to protect things from get/put
+ * race when found cached connection is freed by
+ * ptlrpc_connection_put().
+ *
+ * It will be freed later in module unload time,
+ * when ptlrpc_connection_fini()->lh_exit->conn_exit()
+ * path is called.
+ */
+ if (atomic_dec_return(&conn->c_refcount) == 1)
+ rc = 1;