linux-kernel - Re: [PATCH][next] iio: adc: ti-ads7950: remove redundant assignment to variable ret

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Date: Mon, 8 Jan 2024 10:45:22 +0300
From: Dan Carpenter <dan.carpenter@...aro.org>
To: Jonathan Cameron <jic23@...nel.org>,
	Justin Chen <justinpopo6@...il.com>
Cc: David Lechner <david@...hnology.com>,
	Colin Ian King <colin.i.king@...il.com>,
	Lars-Peter Clausen <lars@...afoo.de>, linux-iio@...r.kernel.org,
	kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH][next] iio: adc: ti-ads7950: remove redundant assignment
 to variable ret

Justin Chen should have been on the CC list...  It's a little late now
because we've kind of figured things out already, but lets add him
anyway.

regards,
dan carpenter

On Sun, Jan 07, 2024 at 04:02:32PM +0000, Jonathan Cameron wrote:
> On Sat, 6 Jan 2024 12:14:22 -0600
> David Lechner <david@...hnology.com> wrote:
> 
> > On 1/6/24 9:22 AM, Colin Ian King wrote:
> > > Variable ret is being assigned a value that is never read, the variable
> > > is being re-assigned again a few statements later. Remove it.
> > > 
> > > Cleans up clang scan build warning:
> > > warning: Value stored to 'ret' is never read [deadcode.DeadStores]
> > > 
> > > Signed-off-by: Colin Ian King <colin.i.king@...il.com>
> > > ---
> > >   drivers/iio/adc/ti-ads7950.c | 2 --
> > >   1 file changed, 2 deletions(-)
> > > 
> > > diff --git a/drivers/iio/adc/ti-ads7950.c b/drivers/iio/adc/ti-ads7950.c
> > > index 263fc3a1b87e..f975de059ba0 100644
> > > --- a/drivers/iio/adc/ti-ads7950.c
> > > +++ b/drivers/iio/adc/ti-ads7950.c
> > > @@ -441,8 +441,6 @@ static int ti_ads7950_get(struct gpio_chip *chip, unsigned int offset)
> > >   	if (ret)
> > >   		goto out;
> > >   
> > > -	ret = ((st->single_rx >> 12) & BIT(offset)) ? 1 : 0;
> > > -
> > >   	/* Revert back to original settings */
> > >   	st->cmd_settings_bitmask &= ~TI_ADS7950_CR_GPIO_DATA;
> > >   	st->single_tx = TI_ADS7950_MAN_CMD_SETTINGS(st);  
> > 
> > This does not look like the correct fix. This is the intended return value of the function in the case of no errors. So we probably need to introduce a new variable instead so that it doesn't get written over.
> 
> Agreed.  Needs to stash that in another local variable and return that value
> if ret == 0.
> 
> J
>