Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <c310a5e7-e410-dbdb-cada-3eca82a9ceb0@bytedance.com>
Date:   Fri, 14 Apr 2023 23:45:26 +0800
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0)
 Gecko/20100101 Thunderbird/102.9.1
Subject: Re: Re: [PATCH V5 2/5] cachefiles: extract ondemand info field from
 cachefiles_object
To:     David Howells <dhowells@redhat.com>
Cc:     linux-cachefs@redhat.com, linux-erofs@lists.ozlabs.org,
        linux-kernel@vger.kernel.org, jefflexu@linux.alibaba.com,
        hsiangkao@linux.alibaba.com, yinxin.x@bytedance.com,
        zhujia.zj@bytedance.com
References: <20230329140155.53272-3-zhujia.zj@bytedance.com>
 <20230329140155.53272-1-zhujia.zj@bytedance.com>
 <1250339.1681480291@warthog.procyon.org.uk>
From:   Jia Zhu <zhujia.zj@bytedance.com>
In-Reply-To: <1250339.1681480291@warthog.procyon.org.uk>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Precedence: bulk


在 2023/4/14 21:51, David Howells 写道:
> Jia Zhu <zhujia.zj@bytedance.com> wrote:
> 
>>   #define CACHEFILES_OBJECT_STATE_FUNCS(_state, _STATE)	\
>>   static inline bool								\
>>   cachefiles_ondemand_object_is_##_state(const struct cachefiles_object *object) \
>>   {												\
>> -	return object->state == CACHEFILES_ONDEMAND_OBJSTATE_##_STATE; \
>> +	return object->ondemand->state == CACHEFILES_ONDEMAND_OBJSTATE_##_STATE; \
>>   }												\
>>   												\
>>   static inline void								\
>>   cachefiles_ondemand_set_object_##_state(struct cachefiles_object *object) \
>>   {												\
>> -	object->state = CACHEFILES_ONDEMAND_OBJSTATE_##_STATE; \
>> +	object->ondemand->state = CACHEFILES_ONDEMAND_OBJSTATE_##_STATE; \
>>   }
> 
> I wonder if those need barriers - smp_load_acquire() and smp_store_release().
> 
> David

There are three object states: OPEN, CLOSE, REOPENING.

Here is no logic in the code such like: A has to watching and waiting
for B's status change.

And so far I haven't constructed a scenario requires barrier pairs. Thus
I didn't add barriers here.

Jia
>