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authorDmitry Torokhov <dmitry.torokhov@gmail.com>2012-05-02 00:13:36 -0700
committerDmitry Torokhov <dmitry.torokhov@gmail.com>2012-05-02 00:23:14 -0700
commitdba4258068f822b7dafc78c28fe9c99c551eca7e (patch)
tree0df5af1962e330399822c2d21f57a629f0b2d15c
parentf31ad406693f114e57ad4651eb17deb68419c7cb (diff)
Input: evdev - properly access RCU-protected 'grab' data
We should use rcu_dereference_protected() when checking if given client is the one that grabbed the device. This fixes warnings produced by sparse. Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
-rw-r--r--drivers/input/evdev.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index 4b2e10d5d641..9226b4d9118f 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -180,7 +180,10 @@ static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
{
- if (evdev->grab != client)
+ struct evdev_client *grab = rcu_dereference_protected(evdev->grab,
+ lockdep_is_held(&evdev->mutex));
+
+ if (grab != client)
return -EINVAL;
rcu_assign_pointer(evdev->grab, NULL);
@@ -259,8 +262,7 @@ static int evdev_release(struct inode *inode, struct file *file)
struct evdev *evdev = client->evdev;
mutex_lock(&evdev->mutex);
- if (evdev->grab == client)
- evdev_ungrab(evdev, client);
+ evdev_ungrab(evdev, client);
mutex_unlock(&evdev->mutex);
evdev_detach_client(evdev, client);