2014-07-17 20:40:50

by Himangi Saraogi

[permalink] [raw]
Subject: [PATCH] staging: iio: adis16203: Use devm_iio_device_register

This patch introduces the use of iio_device_register and does away with
the call to the corressponding unregister function in the probe and
remove functions of the driver respectively.

Signed-off-by: Himangi Saraogi <[email protected]>
Acked-by: Julia Lawall <[email protected]>
---
drivers/staging/iio/accel/adis16203_core.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/staging/iio/accel/adis16203_core.c b/drivers/staging/iio/accel/adis16203_core.c
index 409a28e..5077779 100644
--- a/drivers/staging/iio/accel/adis16203_core.c
+++ b/drivers/staging/iio/accel/adis16203_core.c
@@ -175,7 +175,7 @@ static int adis16203_probe(struct spi_device *spi)
if (ret)
goto error_cleanup_buffer_trigger;

- ret = iio_device_register(indio_dev);
+ ret = devm_iio_device_register(&spi->dev, indio_dev);
if (ret)
goto error_cleanup_buffer_trigger;

@@ -191,7 +191,6 @@ static int adis16203_remove(struct spi_device *spi)
struct iio_dev *indio_dev = spi_get_drvdata(spi);
struct adis *st = iio_priv(indio_dev);

- iio_device_unregister(indio_dev);
adis_cleanup_buffer_and_trigger(st, indio_dev);

return 0;
--
1.9.1


2014-07-17 20:47:13

by Lars-Peter Clausen

[permalink] [raw]
Subject: Re: [PATCH] staging: iio: adis16203: Use devm_iio_device_register

On 07/17/2014 10:40 PM, Himangi Saraogi wrote:
> This patch introduces the use of iio_device_register and does away with
> the call to the corressponding unregister function in the probe and
> remove functions of the driver respectively.
>
> Signed-off-by: Himangi Saraogi <[email protected]>
> Acked-by: Julia Lawall <[email protected]>

No, you changed the relative order in which iio_device_unregister() and
adis_cleanup_buffer_and_trigger() are called, this opens up the way for race
conditions. Rule of thumb: Don't convert drivers to managed functions if
this will change the order in which functions will called on device removal.

- Lars

> ---
> drivers/staging/iio/accel/adis16203_core.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/staging/iio/accel/adis16203_core.c b/drivers/staging/iio/accel/adis16203_core.c
> index 409a28e..5077779 100644
> --- a/drivers/staging/iio/accel/adis16203_core.c
> +++ b/drivers/staging/iio/accel/adis16203_core.c
> @@ -175,7 +175,7 @@ static int adis16203_probe(struct spi_device *spi)
> if (ret)
> goto error_cleanup_buffer_trigger;
>
> - ret = iio_device_register(indio_dev);
> + ret = devm_iio_device_register(&spi->dev, indio_dev);
> if (ret)
> goto error_cleanup_buffer_trigger;
>
> @@ -191,7 +191,6 @@ static int adis16203_remove(struct spi_device *spi)
> struct iio_dev *indio_dev = spi_get_drvdata(spi);
> struct adis *st = iio_priv(indio_dev);
>
> - iio_device_unregister(indio_dev);
> adis_cleanup_buffer_and_trigger(st, indio_dev);
>
> return 0;
>

2014-07-17 21:08:05

by Julia Lawall

[permalink] [raw]
Subject: Re: [PATCH] staging: iio: adis16203: Use devm_iio_device_register



On Thu, 17 Jul 2014, Lars-Peter Clausen wrote:

> On 07/17/2014 10:40 PM, Himangi Saraogi wrote:
> > This patch introduces the use of iio_device_register and does away with
> > the call to the corressponding unregister function in the probe and
> > remove functions of the driver respectively.
> >
> > Signed-off-by: Himangi Saraogi <[email protected]>
> > Acked-by: Julia Lawall <[email protected]>
>
> No, you changed the relative order in which iio_device_unregister() and
> adis_cleanup_buffer_and_trigger() are called, this opens up the way for race
> conditions. Rule of thumb: Don't convert drivers to managed functions if this
> will change the order in which functions will called on device removal.

Thanks for the information. I was indeed not sure about this.

Unfortunately, removal code is not always perfectly written, and the
operations are not always done in the right order...

julia

> - Lars
>
> > ---
> > drivers/staging/iio/accel/adis16203_core.c | 3 +--
> > 1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/drivers/staging/iio/accel/adis16203_core.c
> > b/drivers/staging/iio/accel/adis16203_core.c
> > index 409a28e..5077779 100644
> > --- a/drivers/staging/iio/accel/adis16203_core.c
> > +++ b/drivers/staging/iio/accel/adis16203_core.c
> > @@ -175,7 +175,7 @@ static int adis16203_probe(struct spi_device *spi)
> > if (ret)
> > goto error_cleanup_buffer_trigger;
> >
> > - ret = iio_device_register(indio_dev);
> > + ret = devm_iio_device_register(&spi->dev, indio_dev);
> > if (ret)
> > goto error_cleanup_buffer_trigger;
> >
> > @@ -191,7 +191,6 @@ static int adis16203_remove(struct spi_device *spi)
> > struct iio_dev *indio_dev = spi_get_drvdata(spi);
> > struct adis *st = iio_priv(indio_dev);
> >
> > - iio_device_unregister(indio_dev);
> > adis_cleanup_buffer_and_trigger(st, indio_dev);
> >
> > return 0;
> >
>
>