linux-kernel - Re: [PATCH][next] iio: invensense: remove redundant initialization of variable period

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Date: Sun, 7 Jan 2024 16:07:36 +0000
From: Jonathan Cameron <jic23@...nel.org>
To: Colin Ian King <colin.i.king@...il.com>
Cc: Lars-Peter Clausen <lars@...afoo.de>, Jean-Baptiste Maneyrol
 <jean-baptiste.maneyrol@....com>, Andy Shevchenko
 <andy.shevchenko@...il.com>, linux-iio@...r.kernel.org,
 kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH][next] iio: invensense: remove redundant initialization
 of variable period

On Sat,  6 Jan 2024 15:32:02 +0000
Colin Ian King <colin.i.king@...il.com> wrote:

> The variable period is being initialized with a value that is never
> read, it is being re-assigned a new value later on before it is read.
> The initialization is redundant and can be removed.
> 
> Cleans up clang scan build warning:
> Value stored to 'period' during its initialization is never
> read [deadcode.DeadStores]
> 
> Signed-off-by: Colin Ian King <colin.i.king@...il.com>
Hi Colin,

I definitely want input from someone who can test this.
There is direct use of ts->period as well as the local
variable that is indeed overwritten as you've noted.
Feels like naming needs some work and perhaps reduce the scope of
the period local variable so it's obvious it was only intended
for more local use than it currently looks like.

Thanks,

Jonathan

> ---
>  drivers/iio/common/inv_sensors/inv_sensors_timestamp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/common/inv_sensors/inv_sensors_timestamp.c b/drivers/iio/common/inv_sensors/inv_sensors_timestamp.c
> index 03823ee57f59..3b0f9598a7c7 100644
> --- a/drivers/iio/common/inv_sensors/inv_sensors_timestamp.c
> +++ b/drivers/iio/common/inv_sensors/inv_sensors_timestamp.c
> @@ -126,7 +126,7 @@ void inv_sensors_timestamp_interrupt(struct inv_sensors_timestamp *ts,
>  	struct inv_sensors_timestamp_interval *it;
>  	int64_t delta, interval;
>  	const uint32_t fifo_mult = fifo_period / ts->chip.clock_period;
> -	uint32_t period = ts->period;
> +	uint32_t period;
>  	bool valid = false;
>  
>  	if (fifo_nb == 0)