patch: Refactor to better support new kinds of patches.

Until now, the code here lumped together what was necessary to create and
destroy patch ports, with what was necessary to identify the patch ports
that were needed.  An upcoming patch will add new reasons to create patch
ports, so this commit more cleanly separates those two functions.

Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Justin Pettit <jpettit@nicira.com>

1 files changed, 35 insertions, 37 deletions

diff --git a/ovn/controller/patch.c b/ovn/controller/patch.c
index 1cce5594f..15135e9c9 100644
--- a/ovn/controller/patch.c
+++ b/ovn/controller/patch.c
@@ -124,19 +124,6 @@ create_patch_ports(struct controller_ctx *ctx,
 }
 
 static void
-init_existing_ports(struct controller_ctx *ctx,
-                    struct shash *existing_ports)
-{
-    const struct ovsrec_port *port;
-
-    OVSREC_PORT_FOR_EACH (port, ctx->ovs_idl) {
-        if (smap_get(&port->external_ids, "ovn-patch-port")) {
-            shash_add(existing_ports, port->name, port);
-        }
-    }
-}
-
-static void
 remove_port(struct controller_ctx *ctx,
             const struct ovsrec_port *port)
 {
@@ -170,11 +157,20 @@ remove_port(struct controller_ctx *ctx,
 static void
 parse_bridge_mappings(struct controller_ctx *ctx,
                       const struct ovsrec_bridge *br_int,
-                      const char *mappings_cfg)
+                      struct shash *existing_ports)
 {
-    struct shash existing_ports = SHASH_INITIALIZER(&existing_ports);
-    init_existing_ports(ctx, &existing_ports);
+    /* Get ovn-bridge-mappings. */
+    const char *mappings_cfg = "";
+    const struct ovsrec_open_vswitch *cfg;
+    cfg = ovsrec_open_vswitch_first(ctx->ovs_idl);
+    if (cfg) {
+        mappings_cfg = smap_get(&cfg->external_ids, "ovn-bridge-mappings");
+        if (!mappings_cfg) {
+            mappings_cfg = "";
+        }
+    }
 
+    /* Create patch ports. */
     char *cur, *next, *start;
     next = start = xstrdup(mappings_cfg);
     while ((cur = strsep(&next, ",")) && *cur) {
@@ -195,20 +191,10 @@ parse_bridge_mappings(struct controller_ctx *ctx,
             continue;
         }
 
-        create_patch_ports(ctx, network, &existing_ports, br_int, ovs_bridge);
-        create_patch_ports(ctx, network, &existing_ports, ovs_bridge, br_int);
+        create_patch_ports(ctx, network, existing_ports, br_int, ovs_bridge);
+        create_patch_ports(ctx, network, existing_ports, ovs_bridge, br_int);
     }
     free(start);
-
-    /* Any ports left in existing_ports are related to configuration that has
-     * been removed, so we should delete the ports now. */
-    struct shash_node *port_node, *port_next_node;
-    SHASH_FOR_EACH_SAFE (port_node, port_next_node, &existing_ports) {
-        struct ovsrec_port *port = port_node->data;
-        shash_delete(&existing_ports, port_node);
-        remove_port(ctx, port);
-    }
-    shash_destroy(&existing_ports);
 }
 
 void
@@ -218,15 +204,27 @@ patch_run(struct controller_ctx *ctx, const struct ovsrec_bridge *br_int)
         return;
     }
 
-    const char *mappings_cfg = "";
-    const struct ovsrec_open_vswitch *cfg;
-
-    cfg = ovsrec_open_vswitch_first(ctx->ovs_idl);
-    if (cfg) {
-        mappings_cfg = smap_get(&cfg->external_ids, "ovn-bridge-mappings");
-        if (!mappings_cfg) {
-            mappings_cfg = "";
+    /* Figure out what patch ports already exist. */
+    struct shash existing_ports = SHASH_INITIALIZER(&existing_ports);
+    const struct ovsrec_port *port;
+    OVSREC_PORT_FOR_EACH (port, ctx->ovs_idl) {
+        if (smap_get(&port->external_ids, "ovn-patch-port")) {
+            shash_add(&existing_ports, port->name, port);
         }
     }
-    parse_bridge_mappings(ctx, br_int, mappings_cfg);
+
+    /* Create in the database any patch ports that should exist.  Remove from
+     * 'existing_ports' any patch ports that do exist in the database and
+     * should be there. */
+    parse_bridge_mappings(ctx, br_int, &existing_ports);
+
+    /* Now 'existing_ports' only still contains patch ports that exist in the
+     * database but shouldn't.  Delete them from the database. */
+    struct shash_node *port_node, *port_next_node;
+    SHASH_FOR_EACH_SAFE (port_node, port_next_node, &existing_ports) {
+        struct ovsrec_port *port = port_node->data;
+        shash_delete(&existing_ports, port_node);
+        remove_port(ctx, port);
+    }
+    shash_destroy(&existing_ports);
 }