linux-kernel - Re: [PATCH 9/9] mfd: max8925-i2c: Drop unnecessary static

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Message-ID: <20170703114201.ybafidokvrwg4how@dell>
Date:   Mon, 3 Jul 2017 12:42:01 +0100
From:   Lee Jones <lee.jones@...aro.org>
To:     Kees Cook <keescook@...omium.org>
Cc:     kernel-janitors@...r.kernel.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Julia Lawall <Julia.Lawall@...6.fr>
Subject: Re: [PATCH 9/9] mfd: max8925-i2c: Drop unnecessary static

On Tue, 27 Jun 2017, Kees Cook wrote:

> On Thu, May 4, 2017 at 1:10 PM, Julia Lawall <Julia.Lawall@...6.fr> wrote:
> > Drop static on a local variable, when the variable is initialized before
> > any use, on every possible execution path through the function.  The static
> > has no benefit, and dropping it reduces the code size.
> >
> > The semantic patch that fixes this problem is as follows:
> > (http://coccinelle.lip6.fr/)
> >
> > // <smpl>
> > @bad exists@
> > position p;
> > identifier x;
> > type T;
> > @@
> >
> > static T x@p;
> > ...
> > x = <+...x...+>
> >
> > @@
> > identifier x;
> > expression e;
> > type T;
> > position p != bad.p;
> > @@
> >
> > -static
> >  T x@p;
> >  ... when != x
> >      when strict
> > ?x = e;
> > // </smpl>
> >
> > The change in code size is indicates by the following output from the size
> > command.
> >
> > before:
> >    text    data     bss     dec     hex filename
> >    2579     240      16    2835     b13 drivers/mfd/max8925-i2c.o
> >
> > after:
> >    text    data     bss     dec     hex filename
> >    2531     240       8    2779     adb drivers/mfd/max8925-i2c.o
> >
> > Signed-off-by: Julia Lawall <Julia.Lawall@...6.fr>
> >
> > ---
> >  drivers/mfd/max8925-i2c.c |    2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/mfd/max8925-i2c.c b/drivers/mfd/max8925-i2c.c
> > index 5c80aea..1006323 100644
> > --- a/drivers/mfd/max8925-i2c.c
> > +++ b/drivers/mfd/max8925-i2c.c
> > @@ -151,7 +151,7 @@ static int max8925_probe(struct i2c_client *client,
> >                                    const struct i2c_device_id *id)
> >  {
> >         struct max8925_platform_data *pdata = dev_get_platdata(&client->dev);
> > -       static struct max8925_chip *chip;
> > +       struct max8925_chip *chip;
> >         struct device_node *node = client->dev.of_node;
> >
> >         if (node && !pdata) {
> >
> 
> Acked-by: Kees Cook <keescook@...omium.org>
> 
> Kernel janitors or Andrew, can you pick this up?

Didn't see this before.

Thanks for the poke Kees, I will pick this up in due course.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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