This prevents use of provider callbacks after it has been unregistered.
Note that all code using this that can be called from a consumer *must*
check the pointer before using and hold the info_exist_lock throughout
the usage of the callbacks in info.
Signed-off-by: Jonathan Cameron <jic23@xxxxxxxxxx>
---
drivers/staging/iio/iio.h | 2 ++
drivers/staging/iio/industrialio-core.c | 4 ++++
2 files changed, 6 insertions(+), 0 deletions(-)
diff --git a/drivers/staging/iio/iio.h b/drivers/staging/iio/iio.h
index be6ced3..478dbe5 100644
--- a/drivers/staging/iio/iio.h
+++ b/drivers/staging/iio/iio.h
@@ -310,6 +310,7 @@ struct iio_buffer_setup_ops {
* @chan_attr_group: [INTERN] group for all attrs in base directory
* @name: [DRIVER] name of the device.
* @info: [DRIVER] callbacks and constant info from driver
+ * @info_exist_lock: [INTERN] lock to prevent use during removal
* @chrdev: [INTERN] associated character device
* @groups: [INTERN] attribute groups
* @groupcounter: [INTERN] index of next attribute group
@@ -340,6 +341,7 @@ struct iio_dev {
struct attribute_group chan_attr_group;
const char *name;
const struct iio_info *info;
+ struct mutex info_exist_lock;
const struct iio_buffer_setup_ops *setup_ops;
struct cdev chrdev;
#define IIO_MAX_GROUPS 6
diff --git a/drivers/staging/iio/industrialio-core.c b/drivers/staging/iio/industrialio-core.c
index e4824fe..3a2d080 100644
--- a/drivers/staging/iio/industrialio-core.c
+++ b/drivers/staging/iio/industrialio-core.c
@@ -594,6 +594,7 @@ struct iio_dev *iio_allocate_device(int sizeof_priv)
device_initialize(&dev->dev);
dev_set_drvdata(&dev->dev, (void *)dev);
mutex_init(&dev->mlock);
+ mutex_init(&dev->info_exist_lock);
dev->id = ida_simple_get(&iio_ida, 0, 0, GFP_KERNEL);
if (dev->id < 0) {
@@ -718,6 +719,9 @@ EXPORT_SYMBOL(iio_device_register);
void iio_device_unregister(struct iio_dev *indio_dev)
{
+ mutex_lock(&indio_dev->info_exist_lock);
+ indio_dev->info = NULL;
+ mutex_unlock(&indio_dev->info_exist_lock);
device_unregister(&indio_dev->dev);
}
EXPORT_SYMBOL(iio_device_unregister);
--
1.7.8.4
--
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