Merge pull request #17969 from donaldsharp/fpm_lost_sends

zebra: Ensure dplane does not send work back to master at wrong time

zebra/zebra_dplane.c

@@ -7528,6 +7528,16 @@ static void dplane_thread_loop(struct event *event)
 		if (!zdplane_info.dg_run)
 			break;
 
+		/*
+		 * The yield should only happen after a bit of work has been
+		 * done but before we pull any new work off any provider
+		 * queue to continue looping.  This is a safe spot to
+		 * do so.
+		 */
+		if (event_should_yield(event)) {
+			reschedule = true;
+			break;
+		}
 		/* Locate next provider */
 		next_prov = dplane_prov_list_next(&zdplane_info.dg_providers,
 						  prov);
@@ -7592,11 +7602,6 @@ static void dplane_thread_loop(struct event *event)
 			zlog_debug("dplane dequeues %d completed work from provider %s",
 				   counter, dplane_provider_get_name(prov));
 
-		if (event_should_yield(event)) {
-			reschedule = true;
-			break;
-		}
-
 		/* Locate next provider */
 		prov = next_prov;
 	}