netdev - Re: [RFC] networking: convert many more places to skb_put

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Date:   Thu, 15 Jun 2017 09:11:56 +0200
From:   Johannes Berg <johannes@...solutions.net>
To:     YUAN Linyu <Linyu.Yuan@...atel-sbell.com.cn>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: [RFC] networking: convert many more places to skb_put_zero()

On Thu, 2017-06-15 at 07:05 +0000, YUAN Linyu wrote:
> > @@
> > type t;
> > expression skb, len;
> > identifier p;
> > @@
> > t *p
> > - = skb_put(skb, len);
> > + = skb_put_zero(skb, len);
> > -memset(p, 0, len);
> > 
> > and it can't figure out that it should remove the variable, without
> > much more work that's not really worth it for one instance :)
> 
> Yes, I agree, 
> it conflict with previous spatch which will keep "pad" variable,
> right?
> 
> I can do it by hand if spatch not work

I could teach spatch, but it's usually faster (for me) to post-process
the spatch changes to remove the extra variable - in this case though,
it's just not worth it at all since there's just a single change and
you already have a separate patch :)

Btw, just made a patch to add and use "skb_put_data()", just doing a
memcpy() into the skb_put() area also has lots of users.

johannes