linux-kernel - Re: [PATCH 7/9] iio: hid-sensor-accel-3d: Drop unnecessary static

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Date:   Sun, 7 May 2017 13:57:01 +0100
From:   Jonathan Cameron <jic23@...nel.org>
To:     Julia Lawall <Julia.Lawall@...6.fr>, Jiri Kosina <jikos@...nel.org>
Cc:     keescook@...omium.org, kernel-janitors@...r.kernel.org,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        Hartmut Knaack <knaack.h@....de>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Peter Meerwald-Stadler <pmeerw@...erw.net>,
        linux-input@...r.kernel.org, linux-iio@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 7/9] iio: hid-sensor-accel-3d: Drop unnecessary static

On 04/05/17 21:10, Julia Lawall wrote:
> Drop static on a local variable, when the variable is initialized before
> 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
>    3879     512       8    4399    112f drivers/iio/accel/hid-sensor-accel-3d.o
> 
> after:
>    text    data     bss     dec     hex filename
>    3863     512       0    4375    1117 drivers/iio/accel/hid-sensor-accel-3d.o
> 
> Signed-off-by: Julia Lawall <Julia.Lawall@...6.fr>
Applied to the togreg branch of iio.git and pushed out as testing for the
autobuilders to play with it.

Thanks,

Jonathan
> 
> ---
>  drivers/iio/accel/hid-sensor-accel-3d.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/accel/hid-sensor-accel-3d.c b/drivers/iio/accel/hid-sensor-accel-3d.c
> index 43a6cb0..2238a26 100644
> --- a/drivers/iio/accel/hid-sensor-accel-3d.c
> +++ b/drivers/iio/accel/hid-sensor-accel-3d.c
> @@ -347,7 +347,7 @@ static int accel_3d_parse_report(struct platform_device *pdev,
>  static int hid_accel_3d_probe(struct platform_device *pdev)
>  {
>  	int ret = 0;
> -	static const char *name;
> +	const char *name;
>  	struct iio_dev *indio_dev;
>  	struct accel_3d_state *accel_state;
>  	const struct iio_chan_spec *channel_spec;
> 
> --
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