diff mbox series

[v6,1/9] iio: adis: add '__adis_enable_irq()' implementation

Message ID 20221122082757.449452-2-ramona.bolboaca@analog.com
State New
Headers
Series Add '__adis_enable_irq()' |

Commit Message

Ramona Bolboaca Nov. 22, 2022, 8:27 a.m. UTC 
  Add '__adis_enable_irq()' implementation which is the unlocked
version of 'adis_enable_irq()'.
Call '__adis_enable_irq()' instead of 'adis_enable_irq()' from
'__adis_intial_startup()' to keep the expected unlocked functionality.

This fix is needed to remove a deadlock for all devices which are
using 'adis_initial_startup()'. The deadlock occurs because the
same mutex is acquired twice, without releasing it.
The mutex is acquired once inside 'adis_initial_startup()', before
calling '__adis_initial_startup()', and once inside
'adis_enable_irq()', which is called by '__adis_initial_startup()'.
The deadlock is removed by calling '__adis_enable_irq()', instead of
'adis_enable_irq()' from within '__adis_initial_startup()'.

Fixes: b600bd7eb3335 ("iio: adis: do not disabe IRQs in 'adis_init()'")
Signed-off-by: Ramona Bolboaca <ramona.bolboaca@analog.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
---
 drivers/iio/imu/adis.c       | 28 ++++++++++------------------
 include/linux/iio/imu/adis.h | 13 ++++++++++++-
 2 files changed, 22 insertions(+), 19 deletions(-)

Comments

Jonathan Cameron Nov. 23, 2022, 8:39 p.m. UTC | #1 
On Tue, 22 Nov 2022 10:27:49 +0200
Ramona Bolboaca <ramona.bolboaca@analog.com> wrote:

> Add '__adis_enable_irq()' implementation which is the unlocked
> version of 'adis_enable_irq()'.
> Call '__adis_enable_irq()' instead of 'adis_enable_irq()' from
> '__adis_intial_startup()' to keep the expected unlocked functionality.
> 
> This fix is needed to remove a deadlock for all devices which are
> using 'adis_initial_startup()'. The deadlock occurs because the
> same mutex is acquired twice, without releasing it.
> The mutex is acquired once inside 'adis_initial_startup()', before
> calling '__adis_initial_startup()', and once inside
> 'adis_enable_irq()', which is called by '__adis_initial_startup()'.
> The deadlock is removed by calling '__adis_enable_irq()', instead of
> 'adis_enable_irq()' from within '__adis_initial_startup()'.
> 
> Fixes: b600bd7eb3335 ("iio: adis: do not disabe IRQs in 'adis_init()'")
> Signed-off-by: Ramona Bolboaca <ramona.bolboaca@analog.com>
> Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Build issue in here that I've fixed up.

> ---
>  drivers/iio/imu/adis.c       | 28 ++++++++++------------------
>  include/linux/iio/imu/adis.h | 13 ++++++++++++-
>  2 files changed, 22 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/iio/imu/adis.c b/drivers/iio/imu/adis.c
> index f7fcfd04f659..bc40240b29e2 100644
> --- a/drivers/iio/imu/adis.c
> +++ b/drivers/iio/imu/adis.c
> @@ -270,23 +270,19 @@ EXPORT_SYMBOL_NS(adis_debugfs_reg_access, IIO_ADISLIB);
>  #endif
>  
>  /**
> - * adis_enable_irq() - Enable or disable data ready IRQ
> + * __adis_enable_irq() - Enable or disable data ready IRQ (unlocked)
>   * @adis: The adis device
>   * @enable: Whether to enable the IRQ
>   *
>   * Returns 0 on success, negative error code otherwise
>   */
> -int adis_enable_irq(struct adis *adis, bool enable)
> +int __adis_enable_irq(struct adis *adis, bool enable)
>  {
> -	int ret = 0;
> +	int ret;
>  	u16 msc;
>  
> -	mutex_lock(&adis->state_lock);
> -
> -	if (adis->data->enable_irq) {
> -		ret = adis->data->enable_irq(adis, enable);
> -		goto out_unlock;
> -	}
> +	if (adis->data->enable_irq)
> +		return adis->data->enable_irq(adis, enable);
>  
>  	if (adis->data->unmasked_drdy) {
>  		if (enable)
> @@ -294,12 +290,12 @@ int adis_enable_irq(struct adis *adis, bool enable)
>  		else
>  			disable_irq(adis->spi->irq);
>  
> -		goto out_unlock;
> +		return 0;
>  	}
>  
>  	ret = __adis_read_reg_16(adis, adis->data->msc_ctrl_reg, &msc);
>  	if (ret)
> -		goto out_unlock;
> +		return ret;
>  
>  	msc |= ADIS_MSC_CTRL_DATA_RDY_POL_HIGH;
>  	msc &= ~ADIS_MSC_CTRL_DATA_RDY_DIO2;
> @@ -308,13 +304,9 @@ int adis_enable_irq(struct adis *adis, bool enable)
>  	else
>  		msc &= ~ADIS_MSC_CTRL_DATA_RDY_EN;
>  
> -	ret = __adis_write_reg_16(adis, adis->data->msc_ctrl_reg, msc);
> -
> -out_unlock:
> -	mutex_unlock(&adis->state_lock);
> -	return ret;
> +	return __adis_write_reg_16(adis, adis->data->msc_ctrl_reg, msc);
>  }
> -EXPORT_SYMBOL_NS(adis_enable_irq, IIO_ADISLIB);
> +EXPORT_SYMBOL_NS(__adis_enable_irq, IIO_ADISLIB);
>  
>  /**
>   * __adis_check_status() - Check the device for error conditions (unlocked)
> @@ -445,7 +437,7 @@ int __adis_initial_startup(struct adis *adis)
>  	 * with 'IRQF_NO_AUTOEN' anyways.
>  	 */
>  	if (!adis->data->unmasked_drdy)
> -		adis_enable_irq(adis, false);
> +		__adis_enable_irq(adis, false);
>  
>  	if (!adis->data->prod_id_reg)
>  		return 0;
> diff --git a/include/linux/iio/imu/adis.h b/include/linux/iio/imu/adis.h
> index 515ca09764fe..d789ecf8d0c8 100644
> --- a/include/linux/iio/imu/adis.h
> +++ b/include/linux/iio/imu/adis.h
> @@ -402,9 +402,20 @@ static inline int adis_update_bits_base(struct adis *adis, unsigned int reg,
>  	__adis_update_bits_base(adis, reg, mask, val, sizeof(val));	\
>  })
>  
> -int adis_enable_irq(struct adis *adis, bool enable);
> +static inline int adis_enable_irq(struct adis *adis, bool enable)
> +{
> +	int ret;
> +
> +	mutex_lock(&adis->state_lock);
> +	ret = __adis_enable_irq(adis, enable);
> +	mutex_unlock(&adis->state_lock);
> +
> +	return ret;
> +}
> +
>  int __adis_check_status(struct adis *adis);
>  int __adis_initial_startup(struct adis *adis);
> +int __adis_enable_irq(struct adis *adis, bool enable);

Move the above down here seeing as __adis_enable_irq() isn't
defined until this point (and that gave a bunch of build issues).

>  
>  static inline int adis_check_status(struct adis *adis)
>  {
diff mbox series

Patch

diff --git a/drivers/iio/imu/adis.c b/drivers/iio/imu/adis.c
index f7fcfd04f659..bc40240b29e2 100644
--- a/drivers/iio/imu/adis.c
+++ b/drivers/iio/imu/adis.c
@@ -270,23 +270,19 @@  EXPORT_SYMBOL_NS(adis_debugfs_reg_access, IIO_ADISLIB);
 #endif
 
 /**
- * adis_enable_irq() - Enable or disable data ready IRQ
+ * __adis_enable_irq() - Enable or disable data ready IRQ (unlocked)
  * @adis: The adis device
  * @enable: Whether to enable the IRQ
  *
  * Returns 0 on success, negative error code otherwise
  */
-int adis_enable_irq(struct adis *adis, bool enable)
+int __adis_enable_irq(struct adis *adis, bool enable)
 {
-	int ret = 0;
+	int ret;
 	u16 msc;
 
-	mutex_lock(&adis->state_lock);
-
-	if (adis->data->enable_irq) {
-		ret = adis->data->enable_irq(adis, enable);
-		goto out_unlock;
-	}
+	if (adis->data->enable_irq)
+		return adis->data->enable_irq(adis, enable);
 
 	if (adis->data->unmasked_drdy) {
 		if (enable)
@@ -294,12 +290,12 @@  int adis_enable_irq(struct adis *adis, bool enable)
 		else
 			disable_irq(adis->spi->irq);
 
-		goto out_unlock;
+		return 0;
 	}
 
 	ret = __adis_read_reg_16(adis, adis->data->msc_ctrl_reg, &msc);
 	if (ret)
-		goto out_unlock;
+		return ret;
 
 	msc |= ADIS_MSC_CTRL_DATA_RDY_POL_HIGH;
 	msc &= ~ADIS_MSC_CTRL_DATA_RDY_DIO2;
@@ -308,13 +304,9 @@  int adis_enable_irq(struct adis *adis, bool enable)
 	else
 		msc &= ~ADIS_MSC_CTRL_DATA_RDY_EN;
 
-	ret = __adis_write_reg_16(adis, adis->data->msc_ctrl_reg, msc);
-
-out_unlock:
-	mutex_unlock(&adis->state_lock);
-	return ret;
+	return __adis_write_reg_16(adis, adis->data->msc_ctrl_reg, msc);
 }
-EXPORT_SYMBOL_NS(adis_enable_irq, IIO_ADISLIB);
+EXPORT_SYMBOL_NS(__adis_enable_irq, IIO_ADISLIB);
 
 /**
  * __adis_check_status() - Check the device for error conditions (unlocked)
@@ -445,7 +437,7 @@  int __adis_initial_startup(struct adis *adis)
 	 * with 'IRQF_NO_AUTOEN' anyways.
 	 */
 	if (!adis->data->unmasked_drdy)
-		adis_enable_irq(adis, false);
+		__adis_enable_irq(adis, false);
 
 	if (!adis->data->prod_id_reg)
 		return 0;
diff --git a/include/linux/iio/imu/adis.h b/include/linux/iio/imu/adis.h
index 515ca09764fe..d789ecf8d0c8 100644
--- a/include/linux/iio/imu/adis.h
+++ b/include/linux/iio/imu/adis.h
@@ -402,9 +402,20 @@  static inline int adis_update_bits_base(struct adis *adis, unsigned int reg,
 	__adis_update_bits_base(adis, reg, mask, val, sizeof(val));	\
 })
 
-int adis_enable_irq(struct adis *adis, bool enable);
+static inline int adis_enable_irq(struct adis *adis, bool enable)
+{
+	int ret;
+
+	mutex_lock(&adis->state_lock);
+	ret = __adis_enable_irq(adis, enable);
+	mutex_unlock(&adis->state_lock);
+
+	return ret;
+}
+
 int __adis_check_status(struct adis *adis);
 int __adis_initial_startup(struct adis *adis);
+int __adis_enable_irq(struct adis *adis, bool enable);
 
 static inline int adis_check_status(struct adis *adis)
 {