linux-kernel - Re: [Outreachy kernel] [PATCH] staging: impedance-analyzer: ad5933: Remove unnecessary goto

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Date:   Sun, 19 Mar 2017 18:56:05 +0100 (CET)
From:   Julia Lawall <julia.lawall@...6.fr>
To:     simran singhal <singhalsimran0@...il.com>
cc:     lars@...afoo.de, Michael.Hennerich@...log.com, jic23@...nel.org,
        Hartmut Knaack <knaack.h@....de>,
        Peter Meerwald-Stadler <pmeerw@...erw.net>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-iio@...r.kernel.org, devel@...verdev.osuosl.org,
        linux-kernel@...r.kernel.org, outreachy-kernel@...glegroups.com
Subject: Re: [Outreachy kernel] [PATCH] staging: impedance-analyzer: ad5933:
 Remove unnecessary goto



On Sun, 19 Mar 2017, simran singhal wrote:

> Remove unnecessary goto.
>
> Signed-off-by: simran singhal <singhalsimran0@...il.com>
> ---
>  drivers/staging/iio/impedance-analyzer/ad5933.c | 10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/staging/iio/impedance-analyzer/ad5933.c b/drivers/staging/iio/impedance-analyzer/ad5933.c
> index 297665d..c9ed2ac 100644
> --- a/drivers/staging/iio/impedance-analyzer/ad5933.c
> +++ b/drivers/staging/iio/impedance-analyzer/ad5933.c
> @@ -663,12 +663,12 @@ static void ad5933_work(struct work_struct *work)
>  		ad5933_cmd(st, AD5933_CTRL_START_SWEEP);
>  		st->state = AD5933_CTRL_START_SWEEP;
>  		schedule_delayed_work(&st->work, st->poll_time_jiffies);
> -		goto out;
> +		mutex_unlock(&indio_dev->mlock);

This is not correct.  The code at the end of the function implicitly does
a return, which has disappeared in the change.  You could add a return to
each place wher you have put a mutex_unlock, but I think that the code was
better off as it was.  It's microscopically less error prone to have this
cleanup code in only one place.

julia

>  	}
>
>  	ret = ad5933_i2c_read(st->client, AD5933_REG_STATUS, 1, &status);
>  	if (ret)
> -		goto out;
> +		mutex_unlock(&indio_dev->mlock);
>
>  	if (status & AD5933_STAT_DATA_VALID) {
>  		int scan_count = bitmap_weight(indio_dev->active_scan_mask,
> @@ -678,7 +678,7 @@ static void ad5933_work(struct work_struct *work)
>  				AD5933_REG_REAL_DATA : AD5933_REG_IMAG_DATA,
>  				scan_count * 2, (u8 *)buf);
>  		if (ret)
> -			goto out;
> +			mutex_unlock(&indio_dev->mlock);
>
>  		if (scan_count == 2) {
>  			val[0] = be16_to_cpu(buf[0]);
> @@ -690,7 +690,7 @@ static void ad5933_work(struct work_struct *work)
>  	} else {
>  		/* no data available - try again later */
>  		schedule_delayed_work(&st->work, st->poll_time_jiffies);
> -		goto out;
> +		mutex_unlock(&indio_dev->mlock);
>  	}
>
>  	if (status & AD5933_STAT_SWEEP_DONE) {
> @@ -703,8 +703,6 @@ static void ad5933_work(struct work_struct *work)
>  		ad5933_cmd(st, AD5933_CTRL_INC_FREQ);
>  		schedule_delayed_work(&st->work, st->poll_time_jiffies);
>  	}
> -out:
> -	mutex_unlock(&indio_dev->mlock);
>  }
>
>  static int ad5933_probe(struct i2c_client *client,
> --
> 2.7.4
>
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