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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: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Lars-Peter Clausen 2013-10-04 12:07:00 +01:00 committed by Jonathan Cameron
parent d2f0a48f36
commit a95194569f
1 changed files with 26 additions and 3 deletions
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29
drivers/iio/industrialio-buffer.c
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@ -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)