Patch "iio: accel: mma8452: use the correct logic to get mma8452_data" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    iio: accel: mma8452: use the correct logic to get mma8452_data

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     iio-accel-mma8452-use-the-correct-logic-to-get-mma84.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 8a2644dc664f70c88f6c8bfe81136d3d180fa05e
Author: Haibo Chen <haibo.chen@xxxxxxx>
Date:   Tue Feb 22 10:42:21 2022 +0800

    iio: accel: mma8452: use the correct logic to get mma8452_data
    
    [ Upstream commit c87b7b12f48db86ac9909894f4dc0107d7df6375 ]
    
    The original logic to get mma8452_data is wrong, the *dev point to
    the device belong to iio_dev. we can't use this dev to find the
    correct i2c_client. The original logic happen to work because it
    finally use dev->driver_data to get iio_dev. Here use the API
    to_i2c_client() is wrong and make reader confuse. To correct the
    logic, it should be like this
    
      struct mma8452_data *data = iio_priv(dev_get_drvdata(dev));
    
    But after commit 8b7651f25962 ("iio: iio_device_alloc(): Remove
    unnecessary self drvdata"), the upper logic also can't work.
    When try to show the avialable scale in userspace, will meet kernel
    dump, kernel handle NULL pointer dereference.
    
    So use dev_to_iio_dev() to correct the logic.
    
    Dual fixes tags as the second reflects when the bug was exposed, whilst
    the first reflects when the original bug was introduced.
    
    Fixes: c3cdd6e48e35 ("iio: mma8452: refactor for seperating chip specific data")
    Fixes: 8b7651f25962 ("iio: iio_device_alloc(): Remove unnecessary self drvdata")
    Signed-off-by: Haibo Chen <haibo.chen@xxxxxxx>
    Reviewed-by: Martin Kepplinger <martink@xxxxxxxxx>
    Cc: <Stable@xxxxxxxxxxxxxxx>
    Link: https://lore.kernel.org/r/1645497741-5402-1-git-send-email-haibo.chen@xxxxxxx
    Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
index 373b59557afe..1f46a73aafea 100644
--- a/drivers/iio/accel/mma8452.c
+++ b/drivers/iio/accel/mma8452.c
@@ -380,8 +380,8 @@ static ssize_t mma8452_show_scale_avail(struct device *dev,
 					struct device_attribute *attr,
 					char *buf)
 {
-	struct mma8452_data *data = iio_priv(i2c_get_clientdata(
-					     to_i2c_client(dev)));
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct mma8452_data *data = iio_priv(indio_dev);
 
 	return mma8452_show_int_plus_micros(buf, data->chip_info->mma_scales,
 		ARRAY_SIZE(data->chip_info->mma_scales));