linux-kernel - Re: [PATCH] irqchip/gic/realview: remove unnecessary static in realview_gic_of

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Message-ID: <20170712125701.GA921@io.lakedaemon.net>
Date:   Wed, 12 Jul 2017 12:57:01 +0000
From:   Jason Cooper <jason@...edaemon.net>
To:     "Gustavo A. R. Silva" <garsilva@...eddedor.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Marc Zyngier <marc.zyngier@....com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] irqchip/gic/realview: remove unnecessary static in
 realview_gic_of_init()

Hi Gustavo,

On Tue, Jul 04, 2017 at 04:26:22PM -0500, Gustavo A. R. Silva wrote:
> Remove unnecessary static on local variable _map_.
> Such variable is initialized before being used,
> on every execution path throughout the function.
> The static has no benefit and, removing it reduces
> the code size.
> 
> This issue was detected using Coccinelle and the following semantic patch:
> 
> @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;
> 
> In the following log you can see the difference in the code size. Also,
> notice that the bss segment size is reduced down to zero. This log is
> the output of the size command, before and after the code change:
> 
> before:
>    text    data     bss     dec     hex filename
>    2187     272      64    2523     9db drivers/irqchip/irq-gic-realview.o
> 
> after:
>    text    data     bss     dec     hex filename
>    2171     216       0    2387     953 drivers/irqchip/irq-gic-realview.o
> 
> Signed-off-by: Gustavo A. R. Silva <garsilva@...eddedor.com>

Acked-by: Jason Cooper <jason@...edaemon.net>

thx,

Jason.