From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
It was possible to unregister an already unregistered v4l2_device struct.
Add a check whether that already happened and just return if that was
the case.
Also refure to register a v4l2_device if both the dev and name fields are
empty. A warning was already produced in that case, but since the name field
is now used to detect whether or not the v4l2_device was already unregistered
this particular combination should be rejected.
Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
---
drivers/media/v4l2-core/v4l2-device.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/media/v4l2-core/v4l2-device.c b/drivers/media/v4l2-core/v4l2-device.c
index 8ed5da2..7f3f822 100644
--- a/drivers/media/v4l2-core/v4l2-device.c
+++ b/drivers/media/v4l2-core/v4l2-device.c
@@ -44,7 +44,8 @@ int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev)
v4l2_dev->dev = dev;
if (dev == NULL) {
/* If dev == NULL, then name must be filled in by the caller */
- WARN_ON(!v4l2_dev->name[0]);
+ if (WARN_ON(!v4l2_dev->name[0]))
+ return -EINVAL;
return 0;
}
@@ -105,7 +106,9 @@ void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
{
struct v4l2_subdev *sd, *next;
- if (v4l2_dev == NULL)
+ /* Just return if v4l2_dev is NULL or if it was already
+ * unregistered before. */
+ if (v4l2_dev == NULL || !v4l2_dev->name[0])
return;
v4l2_device_disconnect(v4l2_dev);
@@ -135,6 +138,8 @@ void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
}
#endif
}
+ /* Mark as unregistered, thus preventing duplicate unregistrations */
+ v4l2_dev->name[0] = '\0';
}
EXPORT_SYMBOL_GPL(v4l2_device_unregister);
--
1.7.10.4
--
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