linux-kernel - Re: [PATCH v2 3/3] crypto: hisilicon/qm - defining the device isolation strategy

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Date:   Wed, 15 Jun 2022 17:10:48 +0800
From:   "yekai(A)" <yekai13@...wei.com>
To:     Greg KH <gregkh@...uxfoundation.org>
CC:     <herbert@...dor.apana.org.au>, <linux-crypto@...r.kernel.org>,
        <linux-accelerators@...ts.ozlabs.org>,
        <linux-kernel@...r.kernel.org>, <linuxarm@...wei.com>,
        <zhangfei.gao@...aro.org>, <wangzhou1@...ilicon.com>
Subject: Re: [PATCH v2 3/3] crypto: hisilicon/qm - defining the device
 isolation strategy



On 2022/6/14 21:29, Greg KH wrote:
> On Tue, Jun 14, 2022 at 09:24:08PM +0800, yekai(A) wrote:
>>>>  struct hisi_qm {
>>>>  	enum qm_hw_ver ver;
>>>>  	enum qm_fun_type fun_type;
>>>> @@ -335,6 +341,9 @@ struct hisi_qm {
>>>>  	struct qm_shaper_factor *factor;
>>>>  	u32 mb_qos;
>>>>  	u32 type_rate;
>>>> +	struct list_head uacce_hw_errs;
>>>> +	atomic_t uacce_ref; /* reference of the uacce */
>>>
>>> That is not how reference counts work, sorry.  Please use 'struct kref'
>>> for a real reference count, never roll your own.
>>>
>>> thanks,
>>>
>>> greg k-h
>>> .
>>>
>>
>> this atomic_t reference is lightweight than 'struct kref',
>
> It's the same size, why would it be "lighter"?  Why do you need it to be
> lighter, what performance issue is there with a kref?
>
>> this reference
>> means whether the task is running. So would it be better to use atomic_t
>> reference?
>
> I do not know, as "running or not running" is a state, not a count or a
> reference.  why does this have to be atomic at all?
>
> thanks,
>
> greg k-h
> .
>

I will use 'qm_state' instead of reference count by zhangfei Gao's opinion.

Thanks
Kai