Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH 1/6] scsi: hisi_sas: Add support for DIX feature for v3 hw
To:     "Martin K. Petersen" <martin.petersen@oracle.com>,
        John Garry <john.garry@huawei.com>
References: <1549450376-114929-1-git-send-email-john.garry@huawei.com>
 <1549450376-114929-2-git-send-email-john.garry@huawei.com>
 <yq1zhr5vpos.fsf@oracle.com>
CC:     <jejb@linux.vnet.ibm.com>, <linuxarm@huawei.com>,
        <linux-kernel@vger.kernel.org>, <linux-scsi@vger.kernel.org>
From:   "chenxiang (M)" <chenxiang66@hisilicon.com>
Message-ID: <53c516cc-cce3-a3e1-718f-6fc465b6e401@hisilicon.com>
Date:   Mon, 11 Feb 2019 19:36:01 +0800
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101
 Thunderbird/45.2.0
MIME-Version: 1.0
In-Reply-To: <yq1zhr5vpos.fsf@oracle.com>
Content-Type: text/plain; charset="gbk"; format=flowed
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Hi Martin,

?? 2019/2/9 7:13, Martin K. Petersen д??:
> John,
>
> Just noticed this while inspecting the resulting complete diff:
>
>>   static u32 get_prot_chk_msk_v3_hw(struct scsi_cmnd *scsi_cmnd)
>>   {
>>   	unsigned char prot_flags = scsi_cmnd->prot_flags;
>>   
>> -	if (prot_flags & SCSI_PROT_TRANSFER_PI) {
>> -		if (prot_flags & SCSI_PROT_REF_CHECK)
>> -			return 0xc << 16;
>> -		return 0xfc << 16;
>> -	}
>> -	return 0;
>> +	if (prot_flags & SCSI_PROT_REF_CHECK)
>> +		return T10_CHK_APP_TAG_MSK;
> Polarity is a bit unclear here. Is this statement disabling checking of
> the app tag?

Yes, disabling checking of app tag.
For here, 1'b0 presents the related byte in DIF will be checked, and 
1'b1 presents the related byte in DIF will not be checked.


>
>> +	return T10_CHK_REF_TAG_MSK | T10_CHK_APP_TAG_MSK;
>>   }