From 9e882e3bc97c7774b93f3db483d2e75767b5cad1 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Wed, 12 Jun 2013 06:04:04 -0300 Subject: [PATCH] [media] v4l2-device: check if already unregistered 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 refuse 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 Signed-off-by: Mauro Carvalho Chehab --- 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 2dbfebc0ca85..02d1b6327117 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); -- 2.20.1