[PATCH iproute2-next v3] devlink: support kernel-side snapshot id allocation

[Jakub Kicinski <kuba@kernel.org>]

Make ID argument optional and read the snapshot info
that kernel sends us.

$ devlink region new netdevsim/netdevsim1/dummy
netdevsim/netdevsim1/dummy: snapshot 0
$ devlink -jp region new netdevsim/netdevsim1/dummy
{
    "regions": {
        "netdevsim/netdevsim1/dummy": {
            "snapshot": [ 1 ]
        }
    }
}
$ devlink region show netdevsim/netdevsim1/dummy
netdevsim/netdevsim1/dummy: size 32768 snapshot [0 1]

v3: back to v1..

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 devlink/devlink.c | 26 +++++++++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/devlink/devlink.c b/devlink/devlink.c
index bd48a73bc0e4..507972c360a7 100644
--- a/devlink/devlink.c
+++ b/devlink/devlink.c
@@ -6476,6 +6476,23 @@ static int cmd_region_read(struct dl *dl)
 	return err;
 }
 
+static int cmd_region_snapshot_new_cb(const struct nlmsghdr *nlh, void *data)
+{
+	struct genlmsghdr *genl = mnl_nlmsg_get_payload(nlh);
+	struct nlattr *tb[DEVLINK_ATTR_MAX + 1] = {};
+	struct dl *dl = data;
+
+	mnl_attr_parse(nlh, sizeof(*genl), attr_cb, tb);
+	if (!tb[DEVLINK_ATTR_BUS_NAME] || !tb[DEVLINK_ATTR_DEV_NAME] ||
+	    !tb[DEVLINK_ATTR_REGION_NAME] ||
+	    !tb[DEVLINK_ATTR_REGION_SNAPSHOT_ID])
+		return MNL_CB_ERROR;
+
+	pr_out_region(dl, tb);
+
+	return MNL_CB_OK;
+}
+
 static int cmd_region_snapshot_new(struct dl *dl)
 {
 	struct nlmsghdr *nlh;
@@ -6484,12 +6501,15 @@ static int cmd_region_snapshot_new(struct dl *dl)
 	nlh = mnlg_msg_prepare(dl->nlg, DEVLINK_CMD_REGION_NEW,
 			       NLM_F_REQUEST | NLM_F_ACK);
 
-	err = dl_argv_parse_put(nlh, dl, DL_OPT_HANDLE_REGION |
-				DL_OPT_REGION_SNAPSHOT_ID, 0);
+	err = dl_argv_parse_put(nlh, dl, DL_OPT_HANDLE_REGION,
+				DL_OPT_REGION_SNAPSHOT_ID);
 	if (err)
 		return err;
 
-	return _mnlg_socket_sndrcv(dl->nlg, nlh, NULL, NULL);
+	pr_out_section_start(dl, "regions");
+	err = _mnlg_socket_sndrcv(dl->nlg, nlh, cmd_region_snapshot_new_cb, dl);
+	pr_out_section_end(dl);
+	return err;
 }
 
 static void cmd_region_help(void)
-- 
2.25.4