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Message-ID: <b8feb625dd2ba0d0dfc298a2f39ca1d8368ba5c9.camel@perches.com>
Subject: Re: [PATCH mm] tracing: incorrect gfp_t conversion
From:   Joe Perches <joe@perches.com>
To:     Andrew Morton <akpm@linux-foundation.org>,
        Vasily Averin <vvs@openvz.org>
Cc:     Steven Rostedt <rostedt@goodmis.org>,
        Ingo Molnar <mingo@redhat.com>, kernel@openvz.org,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org
Date:   Sun, 08 May 2022 13:51:55 -0700
In-Reply-To: <20220507154835.4d4d737d8eed579969f15938@linux-foundation.org>
References: <e1c09bbb-2c58-a986-c704-1db538da905a@openvz.org>
         <331d88fe-f4f7-657c-02a2-d977f15fbff6@openvz.org>
         <20220507123728.f20d977eba9fbb66bddee722@linux-foundation.org>
         <8b1cfefa-da7d-3376-cf04-1ff77dab8170@openvz.org>
         <20220507154835.4d4d737d8eed579969f15938@linux-foundation.org>
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On Sat, 2022-05-07 at 15:48 -0700, Andrew Morton wrote:
> On Sun, 8 May 2022 01:28:58 +0300 Vasily Averin <vvs@openvz.org> wrote:
> 
> > On 5/7/22 22:37, Andrew Morton wrote:
> > > On Sat, 7 May 2022 22:02:05 +0300 Vasily Averin <vvs@openvz.org> wrote:
> > > > +	{(__force unsigned long)GFP_KERNEL,		"GFP_KERNEL"},		\
> > > > +	{(__force unsigned long)GFP_NOFS,		"GFP_NOFS"},		\
> > > 
> > > This got all repetitive, line-wrappy and ugly :(
> > > 
> > > What do we think of something silly like this?
> > 
> > > --- a/include/trace/events/mmflags.h~tracing-incorrect-gfp_t-conversion-fix
> > > +++ a/include/trace/events/mmflags.h
> > > @@ -13,53 +13,57 @@
> > >   * Thus most bits set go first.
> > >   */
> > >  
> > > +#define FUL __force unsigned long
> > > +
> > >  #define __def_gfpflag_names						\
> > > -	{(__force unsigned long)GFP_TRANSHUGE,		"GFP_TRANSHUGE"},	\
> > > -	{(__force unsigned long)GFP_TRANSHUGE_LIGHT,	"GFP_TRANSHUGE_LIGHT"}, \
> > ...
> > > +	{(FUL)GFP_TRANSHUGE,		"GFP_TRANSHUGE"},	\
> > > +	{(FUL)GFP_TRANSHUGE_LIGHT,	"GFP_TRANSHUGE_LIGHT"}, \
> > 
> > 
> > I think it's a good idea, and I regret it was your idea and not mine.
> 
> heh
> 
> > Should I resend my patch with these changes or would you prefer 
> > to keep your patch as a separate one?
> 
> I did the below.  I'll squash them together later.

Very repetitive indeed.

Why not use another stringifying macro?

Maybe something like:

#define gfpflag_string(GFP)	\
	{(__force unsigned long)GFP, #GFP)}

#define __def_gfpflag_names			\
	gfp_flag_string(GFP_TRANSHUGE),		\
	etc...