Re: [patch iproute2-main] devlink: load port-ifname map on demand

[Jiri Pirko <jiri@resnulli.us>]

Actually, please scratch this for now. Depends on Jacob's "devlink:
remove dl_argv_parse_put" patch. Somehow I got the impression it is
already merged.

Sorry for the fuzz.


Thu, Aug 18, 2022 at 10:28:56AM CEST, jiri@resnulli.us wrote:
>From: Jiri Pirko <jiri@nvidia.com>
>
>So far, the port-ifname map was loaded during devlink init
>no matter if actually needed or not. Port dump cmd which is utilized
>for this in kernel takes lock for every devlink instance.
>That may lead to unnecessary blockage of command.
>
>Load the map only in time it is needed to lookup ifname.
>
>Signed-off-by: Jiri Pirko <jiri@nvidia.com>
>---
> devlink/devlink.c | 31 ++++++++++++++++++-------------
> 1 file changed, 18 insertions(+), 13 deletions(-)
>
>diff --git a/devlink/devlink.c b/devlink/devlink.c
>index 21f26246f91b..4ef5dc4a5600 100644
>--- a/devlink/devlink.c
>+++ b/devlink/devlink.c
>@@ -374,6 +374,7 @@ struct dl {
> 	bool verbose;
> 	bool stats;
> 	bool hex;
>+	bool map_loaded;
> 	struct {
> 		bool present;
> 		char *bus_name;
>@@ -816,13 +817,15 @@ static void ifname_map_fini(struct dl *dl)
> 	}
> }
> 
>-static int ifname_map_init(struct dl *dl)
>+static void ifname_map_init(struct dl *dl)
> {
>-	struct nlmsghdr *nlh;
>-	int err;
>-
> 	INIT_LIST_HEAD(&dl->ifname_map_list);
>+}
> 
>+static int ifname_map_load(struct dl *dl)
>+{
>+	struct nlmsghdr *nlh;
>+	int err;
> 
> 	nlh = mnlu_gen_socket_cmd_prepare(&dl->nlg, DEVLINK_CMD_PORT_GET,
> 			       NLM_F_REQUEST | NLM_F_ACK | NLM_F_DUMP);
>@@ -840,7 +843,16 @@ static int ifname_map_lookup(struct dl *dl, const char *ifname,
> 			     uint32_t *p_port_index)
> {
> 	struct ifname_map *ifname_map;
>+	int err;
> 
>+	if (!dl->map_loaded) {
>+		err = ifname_map_load(dl);
>+		if (err) {
>+			pr_err("Failed to create index map\n");
>+			return err;
>+		}
>+		dl->map_loaded = true;
>+	}
> 	list_for_each_entry(ifname_map, &dl->ifname_map_list, list) {
> 		if (strcmp(ifname, ifname_map->ifname) == 0) {
> 			*p_bus_name = ifname_map->bus_name;
>@@ -9528,17 +9540,10 @@ static int dl_init(struct dl *dl)
> 		return -errno;
> 	}
> 
>-	err = ifname_map_init(dl);
>-	if (err) {
>-		pr_err("Failed to create index map\n");
>-		goto err_ifname_map_create;
>-	}
>+	ifname_map_init(dl);
>+
> 	new_json_obj_plain(dl->json_output);
> 	return 0;
>-
>-err_ifname_map_create:
>-	mnlu_gen_socket_close(&dl->nlg);
>-	return err;
> }
> 
> static void dl_fini(struct dl *dl)
>-- 
>2.37.1
>