[PATCH] uacce: fix concurrency of fops_open and uacce_remove

[Jean-Philippe Brucker]

On Fri, Jun 17, 2022 at 10:23:13PM +0800, Zhangfei Gao wrote:
> @@ -312,12 +345,20 @@ static ssize_t available_instances_show(struct device
> *dev,
>                      char *buf)
>  {
>      struct uacce_device *uacce = to_uacce_device(dev);
> +    ssize_t ret;
> 
> -    if (!uacce->ops->get_available_instances)
> -        return -ENODEV;
> +    mutex_lock(&uacce_mutex);
> +    if (!uacce->ops || !uacce->ops->get_available_instances) {

Doesn't the sysfs group go away with uacce_remove()?  We shouldn't need
this check

Thanks,
Jean