Subject: Re: [RFC net-next 2/6] devlink: add version reporting API

From: Jiri Pirko <[email-masked]>
Date: Tue, 15 Jan 2019 11:12:17 +0100

Tue, Jan 15, 2019 at 01:50:04AM CET, [email-masked] wrote:

[...]

>@@ -3701,6 +3732,40 @@ static int devlink_nl_cmd_info_get_dumpit(struct sk_buff *msg,
> 	return msg->len;
> }
> 
>+int devlink_versions_report(struct sk_buff *skb, enum devlink_attr attr,
>+			    const char *version_name, const char *version_value)

Hmm, so this is a helper to construct the msg. I think it would be good
to have this somehow separated from the netlink. Meaning a separate enum
just for fixed/running/stored and perhaps a "context structure" which
you can use just as a pointer with layout invisible for the driver
(containing skb). Passing skb itself is a bit confusing and gives the
driver opportunity to put in some weird crap. Better to disallow it by
the api design.

>+{
>+	struct nlattr *nest;
>+	int err;
>+
>+	if (attr < DEVLINK_ATTR_INFO_VERSIONS_FIXED ||
>+	    attr > DEVLINK_ATTR_INFO_VERSIONS_STORED)
>+		return -EINVAL;
>+
>+	nest = nla_nest_start(skb, attr);
>+	if (!nest)
>+		return -EMSGSIZE;
>+
>+	err = nla_put_string(skb, DEVLINK_ATTR_INFO_VERSIONS_NAME,
>+			     version_name);
>+	if (err)
>+		goto nla_put_failure;
>+
>+	err = nla_put_string(skb, DEVLINK_ATTR_INFO_VERSIONS_VALUE,
>+			     version_value);
>+	if (err)
>+		goto nla_put_failure;
>+
>+	nla_nest_end(skb, nest);
>+
>+	return 0;
>+
>+nla_put_failure:
>+	nla_nest_cancel(skb, nest);
>+	return err;
>+}
>+EXPORT_SYMBOL_GPL(devlink_versions_report);
>+
> static const struct nla_policy devlink_nl_policy[DEVLINK_ATTR_MAX + 1] = {
> 	[DEVLINK_ATTR_BUS_NAME] = { .type = NLA_NUL_STRING },
> 	[DEVLINK_ATTR_DEV_NAME] = { .type = NLA_NUL_STRING },
>-- 
>2.19.2
>