[RFC PATCH v2 1/2] devlink: add support for DEVLINK_CMD_REGION_NEW

[Jacob Keller <jacob.e.keller@intel.com>]

Add support to request that a new snapshot be taken immediately for
a devlink region. Optionally allow specifying the snapshot id to use. If
no snapshot id is provided, the kernel will select a suitable id
automatically.

If the region does not support snapshots on demand, the command will
return an error indicating the operation is not supported.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
---
 devlink/devlink.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/devlink/devlink.c b/devlink/devlink.c
index f9e58c1d7394..71c300ba16ed 100644
--- a/devlink/devlink.c
+++ b/devlink/devlink.c
@@ -6347,10 +6347,27 @@ static int cmd_region_read(struct dl *dl)
 	return err;
 }
 
+static int cmd_region_snapshot_new(struct dl *dl)
+{
+	struct nlmsghdr *nlh;
+	int err;
+
+	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);
+	if (err)
+		return err;
+
+	return _mnlg_socket_sndrcv(dl->nlg, nlh, NULL, NULL);
+}
+
 static void cmd_region_help(void)
 {
 	pr_err("Usage: devlink region show [ DEV/REGION ]\n");
 	pr_err("       devlink region del DEV/REGION snapshot SNAPSHOT_ID\n");
+	pr_err("       devlink region new DEV/REGION [snapshot SNAPSHOT_ID]\n");
 	pr_err("       devlink region dump DEV/REGION [ snapshot SNAPSHOT_ID ]\n");
 	pr_err("       devlink region read DEV/REGION [ snapshot SNAPSHOT_ID ] address ADDRESS length LENGTH\n");
 }
@@ -6374,6 +6391,9 @@ static int cmd_region(struct dl *dl)
 	} else if (dl_argv_match(dl, "read")) {
 		dl_arg_inc(dl);
 		return cmd_region_read(dl);
+	} else if (dl_argv_match(dl, "new")) {
+		dl_arg_inc(dl);
+		return cmd_region_snapshot_new(dl);
 	}
 	pr_err("Command \"%s\" not found\n", dl_argv(dl));
 	return -ENOENT;
-- 
2.25.0.368.g28a2d05eebfb