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Message-ID: <93bda268c5f55571b47c7f283c027454bbcb8469.camel@perches.com>
Subject: Re: [PATCH 2/2] Compiler Attributes: auxdisplay: panel: use
 __fallthrough
From:   Joe Perches <joe@perches.com>
To:     Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc:     Greg KH <gregkh@linuxfoundation.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Dan <dan.carpenter@oracle.com>,
        Andreas Dilger <adilger.kernel@dilger.ca>,
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Date:   Mon, 22 Oct 2018 08:48:11 -0700
In-Reply-To: <CANiq72=Eo-c7M1g1gmE0kXNpxe4vkOBT54n9gMB9UBSEfzTMAw@mail.gmail.com>
References: <20181021171414.22674-1-miguel.ojeda.sandonis@gmail.com>
         <20181021171414.22674-3-miguel.ojeda.sandonis@gmail.com>
         <f46baa5bb0e3373c89d09b6e0d15170902e5f55c.camel@perches.com>
         <CANiq72=Eo-c7M1g1gmE0kXNpxe4vkOBT54n9gMB9UBSEfzTMAw@mail.gmail.com>
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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.