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Date:   Mon, 20 Jun 2022 14:25:39 +0100
From:   Jean-Philippe Brucker <jean-philippe@linaro.org>
To:     Zhangfei Gao <zhangfei.gao@linaro.org>
Cc:     Yang Shen <shenyang39@huawei.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
        linux-crypto@vger.kernel.org, linux-accelerators@lists.ozlabs.org
Subject: Re: [PATCH] uacce: fix concurrency of fops_open and uacce_remove
Message-ID: <YrB1U29QVHcKV3g8@myrica>
References: <20220610123423.27496-1-zhangfei.gao@linaro.org>
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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