+static int lnet_process_id_cmp(struct rhashtable_compare_arg *arg,
+ const void *obj)
+{
+ const struct lnet_process_id *lpi = arg->key;
+ const struct ptlrpc_connection *con = obj;
+
+ if (lpi->nid == con->c_peer.nid &&
+ lpi->pid == con->c_peer.pid)
+ return 0;
+ return -ESRCH;
+}
+
+static const struct rhashtable_params conn_hash_params = {
+ .key_len = 1, /* actually variable-length */
+ .key_offset = offsetof(struct ptlrpc_connection, c_peer),
+ .head_offset = offsetof(struct ptlrpc_connection, c_hash),
+ .hashfn = lnet_process_id_hash,
+ .obj_cmpfn = lnet_process_id_cmp,
+};
+
+struct ptlrpc_connection *
+ptlrpc_connection_get(struct lnet_process_id peer, lnet_nid_t self,
+ struct obd_uuid *uuid)
+{
+ struct ptlrpc_connection *conn, *conn2;
+ ENTRY;
+
+ peer.nid = LNetPrimaryNID(peer.nid);
+ conn = rhashtable_lookup_fast(&conn_hash, &peer, conn_hash_params);
+ if (conn) {
+ ptlrpc_connection_addref(conn);
+ GOTO(out, conn);
+ }
+
+ OBD_ALLOC_PTR(conn);
+ if (!conn)
+ RETURN(NULL);
+
+ conn->c_peer = peer;
+ conn->c_self = self;
+ 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 hash will be
+ * returned,otherwise NULL is returned on success.
+ */
+try_again:
+ conn2 = rhashtable_lookup_get_insert_fast(&conn_hash, &conn->c_hash,
+ conn_hash_params);
+ if (conn2) {
+ /* insertion failed */
+ OBD_FREE_PTR(conn);
+ if (IS_ERR(conn2)) {
+ /* hash table could be resizing. */
+ if (PTR_ERR(conn2) == -ENOMEM ||
+ PTR_ERR(conn2) == -EBUSY) {
+ msleep(5);
+ goto try_again;
+ }
+ return NULL;
+ }
+ conn = conn2;
+ ptlrpc_connection_addref(conn);
+ }
+ 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;