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Commit a9519456 authored by Lars-Peter Clausen's avatar Lars-Peter Clausen Committed by Jonathan Cameron
Browse files

iio:buffer: Add proper locking for iio_update_buffers() 



We need to make sure that in-kernel users of iio_update_buffers() do not race
against each other or against unregistration of the device. So we need to take
both the mlock and the info_exist_lock when calling iio_update_buffers() from a
in-kernel consumer.

Signed-off-by: default avatarLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent d2f0a48f

drivers/iio/industrialio-buffer.c

+26 −3
Original line number Diff line number Diff line
@@ -509,7 +509,7 @@ void iio_disable_all_buffers(struct iio_dev *indio_dev) 
		indio_dev->setup_ops->postdisable(indio_dev);

}



int iio_update_buffers(struct iio_dev *indio_dev,

static int __iio_update_buffers(struct iio_dev *indio_dev,

		       struct iio_buffer *insert_buffer,

		       struct iio_buffer *remove_buffer)

{
@@ -674,6 +674,29 @@ int iio_update_buffers(struct iio_dev *indio_dev, 


	return ret;

}



int iio_update_buffers(struct iio_dev *indio_dev,

		       struct iio_buffer *insert_buffer,

		       struct iio_buffer *remove_buffer)

{

	int ret;



	mutex_lock(&indio_dev->info_exist_lock);

	mutex_lock(&indio_dev->mlock);



	if (indio_dev->info == NULL) {

		ret = -ENODEV;

		goto out_unlock;

	}



	ret = __iio_update_buffers(indio_dev, insert_buffer, remove_buffer);



out_unlock:

	mutex_unlock(&indio_dev->mlock);

	mutex_unlock(&indio_dev->info_exist_lock);



	return ret;

}

EXPORT_SYMBOL_GPL(iio_update_buffers);



ssize_t iio_buffer_store_enable(struct device *dev,
@@ -699,10 +722,10 @@ ssize_t iio_buffer_store_enable(struct device *dev, 
		goto done;



	if (requested_state)

		ret = iio_update_buffers(indio_dev,

		ret = __iio_update_buffers(indio_dev,

					 indio_dev->buffer, NULL);

	else

		ret = iio_update_buffers(indio_dev,

		ret = __iio_update_buffers(indio_dev,

					 NULL, indio_dev->buffer);



	if (ret < 0)