linux-kernel - Re: [PATCH 06/10] iio: imu: adis: protect initial startup routine with state lock

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Message-ID: <20191006102001.10e6d9b2@archlinux>
Date:   Sun, 6 Oct 2019 10:20:01 +0100
From:   Jonathan Cameron <jic23@...nel.org>
To:     Alexandru Ardelean <alexandru.ardelean@...log.com>
Cc:     <linux-iio@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 06/10] iio: imu: adis: protect initial startup routine
 with state lock

On Thu, 26 Sep 2019 14:18:08 +0300
Alexandru Ardelean <alexandru.ardelean@...log.com> wrote:

> The initial startup routine is called by some ADIS drivers during probe,
> and before registering with IIO. Normally, userspace should not be able to
> do any access to the device (as there shouldn't be any available).
> 
> This change extends the state lock to the entire initial-startup routine.
> Behaviourally nothing should change, but this should make the library
> function a bit more robust.
> 
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@...log.com>
Applied.

Thanks,

> ---
>  drivers/iio/imu/adis.c | 16 ++++++++++------
>  1 file changed, 10 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/iio/imu/adis.c b/drivers/iio/imu/adis.c
> index b14101bf34b9..7468294d1776 100644
> --- a/drivers/iio/imu/adis.c
> +++ b/drivers/iio/imu/adis.c
> @@ -331,7 +331,7 @@ static int adis_self_test(struct adis *adis)
>  {
>  	int ret;
>  
> -	ret = adis_write_reg_16(adis, adis->data->msc_ctrl_reg,
> +	ret = __adis_write_reg_16(adis, adis->data->msc_ctrl_reg,
>  			adis->data->self_test_mask);
>  	if (ret) {
>  		dev_err(&adis->spi->dev, "Failed to initiate self test: %d\n",
> @@ -341,10 +341,10 @@ static int adis_self_test(struct adis *adis)
>  
>  	msleep(adis->data->startup_delay);
>  
> -	ret = adis_check_status(adis);
> +	ret = __adis_check_status(adis);
>  
>  	if (adis->data->self_test_no_autoclear)
> -		adis_write_reg_16(adis, adis->data->msc_ctrl_reg, 0x00);
> +		__adis_write_reg_16(adis, adis->data->msc_ctrl_reg, 0x00);
>  
>  	return ret;
>  }
> @@ -362,19 +362,23 @@ int adis_initial_startup(struct adis *adis)
>  {
>  	int ret;
>  
> +	mutex_lock(&adis->state_lock);
> +
>  	ret = adis_self_test(adis);
>  	if (ret) {
>  		dev_err(&adis->spi->dev, "Self-test failed, trying reset.\n");
> -		adis_reset(adis);
> +		__adis_reset(adis);
>  		msleep(adis->data->startup_delay);
>  		ret = adis_self_test(adis);
>  		if (ret) {
>  			dev_err(&adis->spi->dev, "Second self-test failed, giving up.\n");
> -			return ret;
> +			goto out_unlock;
>  		}
>  	}
>  
> -	return 0;
> +out_unlock:
> +	mutex_unlock(&adis->state_lock);
> +	return ret;
>  }
>  EXPORT_SYMBOL_GPL(adis_initial_startup);
>