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Date:   Fri, 01 Nov 2019 08:18:17 +0800
From:   cang@codeaurora.org
To:     Mark Salyzyn <salyzyn@android.com>
Cc:     asutoshd@codeaurora.org, nguyenb@codeaurora.org,
        rnayak@codeaurora.org, linux-scsi@vger.kernel.org,
        kernel-team@android.com, saravanak@google.com, salyzyn@google.com,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 1/5] scsi: Adjust DBD setting in mode sense for caching
 mode page per LLD
In-Reply-To: <6bda63c6-4bcf-b7ad-f552-4c72ba0b9024@android.com>
References: <1572318655-28772-1-git-send-email-cang@codeaurora.org>
 <1572318655-28772-2-git-send-email-cang@codeaurora.org>
 <fd78538f-8e5f-2e5f-0107-a8bc284d037d@android.com>
 <6bda63c6-4bcf-b7ad-f552-4c72ba0b9024@android.com>
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On 2019-10-31 23:40, Mark Salyzyn wrote:
> On 10/31/19 8:20 AM, Mark Salyzyn wrote:
>> On 10/28/19 8:10 PM, Can Guo wrote:
>>> Host sends MODE_SENSE_10 with caching mode page, to check if the 
>>> device
>>> supports the cache feature.
>>> UFS JEDEC standards require DBD field to be set to 1.
>>> 
>>> This patch allows LLD to define the setting of DBD if required.
>>> 
>>> Signed-off-by: Can Guo <cang@codeaurora.org>
>>> ---
>>>   drivers/scsi/sd.c        | 6 +++++-
>>>   include/scsi/scsi_host.h | 6 ++++++
>>>   2 files changed, 11 insertions(+), 1 deletion(-)
>>> 
>>> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
>>> index aab4ed8..6d8194f 100644
>>> --- a/drivers/scsi/sd.c
>>> +++ b/drivers/scsi/sd.c
>>> @@ -2629,6 +2629,7 @@ static int sd_try_rc16_first(struct scsi_device 
>>> *sdp)
>>>   {
>>>       int len = 0, res;
>>>       struct scsi_device *sdp = sdkp->device;
>>> +    struct Scsi_Host *host = sdp->host;
>> variable locality
>>>       int dbd;
>>>       int modepage;
>>> @@ -2660,7 +2661,10 @@ static int sd_try_rc16_first(struct 
>>> scsi_device *sdp)
>>>           dbd = 8;
>>>       } else {
>>>           modepage = 8;
>>> -        dbd = 0;
>>> +        if (host->set_dbd_for_caching)
>>> +            dbd = 8;
>>> +        else
>>> +            dbd = 0;
>>>       }
>> 
>> This simplifies to:
>> 
>> -   } else if (sdp->type == TYPE_RBC) {
>> 
>> +    } else if (sdp->type == TYPE_RBC || 
>> sdp->host->set_dbd_for_caching) {
> 
> IDK what happened with my mailer sending out an older infant copy
> (blame on fumble fingers). My final copy was instead the
> simplification:
> 
> +    dbd = sdp->host->set_dbd_for_caching ? 8 : 0;

Thank you for your review.

Regards,
Can Guo