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From: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
Message-ID: <570DA8A4.7090809@cn.fujitsu.com>
Date: Wed, 13 Apr 2016 10:02:12 +0800
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Subject: Re: [Qemu-devel] [PATCH V2 1/3] colo-compare: introduce colo
 compare initlization
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To: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: qemu devel <qemu-devel@nongnu.org>, Jason Wang <jasowang@redhat.com>, Li Zhijian <lizhijian@cn.fujitsu.com>, Gui jianfeng <guijianfeng@cn.fujitsu.com>, Wen Congyang <wency@cn.fujitsu.com>, zhanghailiang <zhang.zhanghailiang@huawei.com>, Yang Hongyang <hongyang.yang@easystack.cn>, "eddie.dong" <eddie.dong@intel.com>

>> +    if (!size) {
>> +        return 0;
>> +    }
>> +
>> +    ret = qemu_chr_fe_write_all(out, (uint8_t *)&len, sizeof(len));
>> +    if (ret != sizeof(len)) {
>> +        goto err;
>> +    }
>> +
>> +    ret = qemu_chr_fe_write_all(out, (uint8_t *)buf, size);
>> +    if (ret != size) {
>> +        goto err;
>> +    }
>> +
> You can make this slightly simpler and save the return 0;

If we want to save the return 0 , the code will be changed like that:

err:
     return (ret < 0 || ret == size) ? ret : -EIO;

I think it too complex to be understood, so should we keep the original ?

>> +    return 0;
>> +
>> +err:
>> +    return ret < 0 ? ret : -EIO;
> err:
>         return ret <= 0 ? ret : -EIO;

This is wrong, if qemu_chr_fe_write_all success, ret will equal size.
return -EIO.

>> +}
>> +
>> +static int compare_chr_can_read(void *opaque)
>> +{
>> +    return COMPARE_READ_LEN_MAX;
>> +}
>>

-- 
Thanks
zhangchen