Re: [PATCH] checkpatch: Whine about ACCESS_ONCE

From: Julia Lawall
Date: Sun Apr 17 2016 - 07:17:58 EST




On Sun, 17 Apr 2016, Joe Perches wrote:

> On Sun, 2016-04-17 at 07:43 +0200, Julia Lawall wrote:
> > On Sat, 16 Apr 2016, Joe Perches wrote:
> > > On Sat, 2016-04-16 at 12:04 -0700, Joe Perches wrote:
> > > > Add a test for use of ACCESS_ONCE that could be written using
> > > > READ_ONCE or WRITE_ONCE.
> > > > 
> > > > --fix it too if desired.
> > > 
> > > And here's a simple coccinelle script that does a
> > > rather better job:
> > > 
> > > $ cat access_once.cocci
> > > @@
> > > expression e1;
> > > expression e2;
> > > @@
> > > 
> > > -     ACCESS_ONCE(e1) = e2
> > > +     WRITE_ONCE(e1, e2)
> > > 
> > > @@
> > > expression e1;
> > > @@
> > > 
> > > -     ACCESS_ONCE(e1)
> > > +     READ_ONCE(e1)
> >
> > Looks good to me.  Is this something to put in the kernel?
>
> Maybe.  There are more than 500 of these ACCESS_ONCE
> uses that could be converted.
>
> The kernel cocci scripts are typically more complicated
> with virtual org/report/context/patch blocks.
>
> So perhaps this needs to be fleshed out more.

I can do that.

julia