On Fri, Oct 16, 2015 at 10:06:48AM -0400, Benjamin Romer wrote:
> From: Tim Sell <Timothy.Sell@xxxxxxxxxx>
>
> This is NOT technically required for the code as it stands now, but will
> be needed for subsequent patches.
>
> Signed-off-by: Tim Sell <Timothy.Sell@xxxxxxxxxx>
> Signed-off-by: Benjamin Romer <benjamin.romer@xxxxxxxxxx>
> ---
> drivers/staging/unisys/visorinput/visorinput.c | 45 ++++++++++++++++++++------
> 1 file changed, 35 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/staging/unisys/visorinput/visorinput.c b/drivers/staging/unisys/visorinput/visorinput.c
> index d23c129..59641d7 100644
> --- a/drivers/staging/unisys/visorinput/visorinput.c
> +++ b/drivers/staging/unisys/visorinput/visorinput.c
> @@ -62,6 +62,7 @@ enum visorinput_device_type {
> * dev_get_drvdata() / dev_set_drvdata() for each struct device.
> */
> struct visorinput_devdata {
> + struct kref kref;
> struct visor_device *dev;
> struct rw_semaphore lock_visor_dev; /* lock for dev */
> struct input_dev *visorinput_dev;
> @@ -346,6 +347,35 @@ register_client_mouse(void *devdata /* opaque on purpose */)
> return visorinput_dev;
> }
>
> +static void
> +unregister_client_input(struct input_dev *visorinput_dev)
> +{
> + if (visorinput_dev)
> + input_unregister_device(visorinput_dev);
> +}
> +
> +static void devdata_release(struct kref *kref)
> +{
> + struct visorinput_devdata *devdata =
> + container_of(kref, struct visorinput_devdata, kref);
> + unregister_client_input(devdata->visorinput_dev);
> + kfree(devdata);
> +}
> +
> +static struct visorinput_devdata *
> +devdata_get(struct visorinput_devdata *devdata)
> +{
> + if (devdata)
> + kref_get(&devdata->kref);
> + return devdata;
> +}
> +
> +static void devdata_put(struct visorinput_devdata *devdata)
> +{
> + if (devdata)
> + kref_put(&devdata->kref, devdata_release);
Are you sure this is safe? Where is your lock protecting two release
functions from happening at the same time?
Please use the kref-with-a-lock functions if at all possible, unless you
can guarantee that they are safe to call without one.
thanks,
greg k-h
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