Subject: Re: [RFC PATCH 2/2] net: convert to nla_get_*_default()

From: Sabrina Dubroca <[email-masked]>
Date: Thu, 24 Oct 2024 16:28:55 +0200

2024-10-24, 14:11:05 +0200, Johannes Berg wrote:
> On Thu, 2024-10-24 at 13:18 +0200, Johannes Berg wrote:
> > From: Johannes Berg <[email-masked]>
> > 
> > This is mostly to illustrate, done with the following spatch:
> > 
> 
> And we can extend that and get bunch more:
> 
> @@
> expression attr, def;
> expression val;
> identifier fn =~ "^nla_get_.*";
> fresh identifier dfn = fn ## "_default";
> @@
> (
> -if (attr)
> -  val = fn(attr);
> -else
> -  val = def;
> +val = dfn(attr, def);
> |
> -if (!attr)
> -  val = def;
> -else
> -  val = fn(attr);
> +val = dfn(attr, def);
> |
> -val = def;
> ... where != val;
> -if (attr)
> -  val = fn(attr);
> +val = dfn(attr, def);
> |
> -if (!attr)
> -  return def;
> -return fn(attr);
> +return dfn(attr, def);
> )

Not really familiar with spatch, but I'm guessing this won't cover:
    val = attr ? getter(attr) : default;

See macsec_validate_attr in drivers/net/macsec.c for some
examples. There are also some cases where we have "if (data &&
data[IFLA_MACSEC_*])" guarding the attribute fetch
(drivers/net/macvlan.c does that too), but I guess you can't really
cover that without adding some kind of "default_with_cond" helpers.

-- 
Sabrina