From a95194569f697a6cc10d00f9b9b3d21b0b820520 Mon Sep 17 00:00:00 2001
From: Lars-Peter Clausen <lars@metafoo.de>
Date: Fri, 4 Oct 2013 12:07:00 +0100
Subject: [PATCH] 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>
---
drivers/iio/industrialio-buffer.c | 29 ++++++++++++++++++++++++++---
1 file changed, 26 insertions(+), 3 deletions(-)
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index 5a46c57a038b1..d6a5455ae51af 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -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 @@ error_ret:
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)
--
2.30.2