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    Subject[PATCH 5.13 099/800] iio: accel: bmc150: Dont make the remove function of the second accelerometer unregister itself
    Date
    From: Hans de Goede <hdegoede@redhat.com>

    commit f407e2dca0f559621114eeaf657880d83f237fbd upstream.

    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@jcline.org>
    Signed-off-by: Hans de Goede <hdegoede@redhat.com>
    Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
    Cc: <Stable@vger.kernel.org>
    Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    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(-)

    --- a/drivers/iio/accel/bmc150-accel-core.c
    +++ b/drivers/iio/accel/bmc150-accel-core.c
    @@ -1816,11 +1816,11 @@ struct i2c_client *bmc150_get_second_dev
    }
    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);

    --- 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

    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

    --- a/drivers/iio/accel/bmc150-accel.h
    +++ b/drivers/iio/accel/bmc150-accel.h
    @@ -18,7 +18,7 @@ int bmc150_accel_core_probe(struct devic
    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;


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