On Sun, 23 May 2021 19:00:56 +0200
Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
> On machines with dual accelerometers described in a single ACPI fwnode,
> the bmc150_accel_probe() instantiates a second i2c-client for the second
> accelerometer.
>
> A pointer to this manually instantiated second i2c-client is stored
> inside the iio_dev's private-data through bmc150_set_second_device(),
> so that the i2c-client can be unregistered from bmc150_accel_remove().
>
> Before this commit bmc150_set_second_device() took only 1 argument so it
> would store the pointer in private-data of the iio_dev belonging to the
> manually instantiated i2c-client, leading to the bmc150_accel_remove()
> call for the second_dev trying to unregister *itself* while it was
> being removed, leading to a deadlock and rmmod hanging.
>
> Change bmc150_set_second_device() to take 2 arguments: 1. The i2c-client
> which is instantiating the second i2c-client for the 2nd accelerometer and
> 2. The second-device pointer itself (which also is an i2c-client).
>
> This will store the second_device pointer in the private data of the
> iio_dev belonging to the (ACPI instantiated) i2c-client for the first
> accelerometer and will make bmc150_accel_remove() unregister the
> second_device i2c-client when called for the first client,
> avoiding the deadlock.
>
> Fixes: 5bfb3a4bd8f6 ("iio: accel: bmc150: Check for a second ACPI device for BOSC0200")
> Cc: Jeremy Cline <jeremy@xxxxxxxxxx>
> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Patches 1 and 2 applied to the fixes-togreg branch of iio.git and marked for stable.
The rest will have to wait for now.
Thanks,
Jonathan
> ---
> drivers/iio/accel/bmc150-accel-core.c | 4 ++--
> drivers/iio/accel/bmc150-accel-i2c.c | 2 +-
> drivers/iio/accel/bmc150-accel.h | 2 +-
> 3 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/iio/accel/bmc150-accel-core.c b/drivers/iio/accel/bmc150-accel-core.c
> index 3a3f67930165..8ff358c37a81 100644
> --- a/drivers/iio/accel/bmc150-accel-core.c
> +++ b/drivers/iio/accel/bmc150-accel-core.c
> @@ -1815,11 +1815,11 @@ struct i2c_client *bmc150_get_second_device(struct i2c_client *client)
> }
> EXPORT_SYMBOL_GPL(bmc150_get_second_device);
>
> -void bmc150_set_second_device(struct i2c_client *client)
> +void bmc150_set_second_device(struct i2c_client *client, struct i2c_client *second_dev)
> {
> struct bmc150_accel_data *data = iio_priv(i2c_get_clientdata(client));
>
> - data->second_device = client;
> + data->second_device = second_dev;
> }
> EXPORT_SYMBOL_GPL(bmc150_set_second_device);
>
> diff --git a/drivers/iio/accel/bmc150-accel-i2c.c b/drivers/iio/accel/bmc150-accel-i2c.c
> index 69f709319484..2afaae0294ee 100644
> --- a/drivers/iio/accel/bmc150-accel-i2c.c
> +++ b/drivers/iio/accel/bmc150-accel-i2c.c
> @@ -70,7 +70,7 @@ static int bmc150_accel_probe(struct i2c_client *client,
>
> second_dev = i2c_acpi_new_device(&client->dev, 1, &board_info);
> if (!IS_ERR(second_dev))
> - bmc150_set_second_device(second_dev);
> + bmc150_set_second_device(client, second_dev);
> }
> #endif
>
> diff --git a/drivers/iio/accel/bmc150-accel.h b/drivers/iio/accel/bmc150-accel.h
> index 6024f15b9700..e30c1698f6fb 100644
> --- a/drivers/iio/accel/bmc150-accel.h
> +++ b/drivers/iio/accel/bmc150-accel.h
> @@ -18,7 +18,7 @@ int bmc150_accel_core_probe(struct device *dev, struct regmap *regmap, int irq,
> const char *name, bool block_supported);
> int bmc150_accel_core_remove(struct device *dev);
> struct i2c_client *bmc150_get_second_device(struct i2c_client *second_device);
> -void bmc150_set_second_device(struct i2c_client *second_device);
> +void bmc150_set_second_device(struct i2c_client *client, struct i2c_client *second_dev);
> extern const struct dev_pm_ops bmc150_accel_pm_ops;
> extern const struct regmap_config bmc150_regmap_conf;
>
