Re: [PATCH 2/2] Compiler Attributes: auxdisplay: panel: use __fallthrough

[Joe Perches <joe@perches.com>]

On Mon, 2018-10-22 at 11:51 +0200, Miguel Ojeda wrote:
> On Sun, Oct 21, 2018 at 8:11 PM Joe Perches <joe@perches.com> wrote:
> > On Sun, 2018-10-21 at 19:14 +0200, Miguel Ojeda wrote:
> > > Let gcc know these cases are meant to fall through to the next label
> > > by annotating them with the new __fallthrough statement attribute;
> > > and remove the comment since it conveys the same information
> > > (which was also parsed by gcc to suppress the warning).
> > 
> > Instead of many individual conversion patches,
> > perhaps a script to do all the conversions at once.
> 
> Note that this was only an example of the attribute (some people asked
> for an example when introducing another one, so I preemptively did it
> for this one).
> 
> Doing the conversion (and how :-) I left it for afterwards, if people
> agree with the attribute.
> 
> > Maybe:
> > 
> > pattern='(?:\/\*\s*fall(?:\s*|\s*\-\s*)thr(?:u|ough)\s*\*\/|\/\/\s*fall\s*thr(?:u|ough)\s*$)'
> > git grep -P -i --name-only "$pattern" -- '*.[ch]' |
> >     xargs perl -p -i -e "s/$pattern/__fallthrough;/gi"
> 
> By the way, I checked first if coccinelle could match input comments,
> but it doesn't, according to Julia. I am also thinking whether a
> compiler plugin could easily do this, but I don't have my hopes high
> given these are comments...
> 
> Also, regardless of how it is done, the patches need to be sent
> individually to maintainers, no?

Not really no.  For instance the spdx license treewide change.
commit b24413180f5600bcb3bb70fbed5cf186b60864bd

> I have a vague memory that big &
> automated conversions were a bit frozen upon in the kernel. Greg...?

There really needs to be some method to do treewide
conversions without involving multiple maintainers.

It'd be a good topic for a maintainer summit one day.