linux-kernel - Re: [PATCH 5/9] mfd: Drop unnecessary static

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Date:   Tue, 27 Jun 2017 16:46:19 -0700
From:   Kees Cook <keescook@...omium.org>
To:     kernel-janitors@...r.kernel.org,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     Tony Lindgren <tony@...mide.com>,
        Julia Lawall <Julia.Lawall@...6.fr>,
        Lee Jones <lee.jones@...aro.org>, linux-omap@...r.kernel.org,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 5/9] mfd: Drop unnecessary static

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 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 increases the code size but decreases the size of the bss segment.
>
> before:
>    text    data     bss     dec     hex filename
>    3369     272     300    3941     f65 drivers/mfd/twl4030-irq.o
>
> after:
>    text    data     bss     dec     hex filename
>    3401     272      28    3701     e75 drivers/mfd/twl4030-irq.o
>
> Signed-off-by: Julia Lawall <Julia.Lawall@...6.fr>
>
> ---
>  drivers/mfd/twl4030-irq.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mfd/twl4030-irq.c b/drivers/mfd/twl4030-irq.c
> index b46c0cf..c775f27 100644
> --- a/drivers/mfd/twl4030-irq.c
> +++ b/drivers/mfd/twl4030-irq.c
> @@ -683,7 +683,7 @@ int twl4030_sih_setup(struct device *dev, int module, int irq_base)
>
>  int twl4030_init_irq(struct device *dev, int irq_num)
>  {
> -       static struct irq_chip  twl4030_irq_chip;
> +       struct irq_chip twl4030_irq_chip;
>         int                     status, i;
>         int                     irq_base, irq_end, nr_irqs;
>         struct                  device_node *node = dev->of_node;
>

Acked-by: Kees Cook <keescook@...omium.org>

Kernel janitors or Andrew, can you pick this up?

Thanks!

-- 
Kees Cook
Pixel Security