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Date:   Thu, 8 Dec 2022 09:28:41 -0800
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Subject: Re: [PATCH v4 1/4] ufs: core: Remove redundant wb check
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To:     Bean Huo <huobean@gmail.com>,
        Arthur Simchaev <Arthur.Simchaev@wdc.com>,
        martin.petersen@oracle.com
Cc:     beanhuo@micron.com, linux-scsi@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <1669550910-9672-1-git-send-email-Arthur.Simchaev@wdc.com>
 <1669550910-9672-2-git-send-email-Arthur.Simchaev@wdc.com>
 <b89f3337-0869-35a8-114d-85e1fd81eb2c@acm.org>
 <0a44763d-8c40-b9e7-6268-01567c401884@gmail.com>
From:   Bart Van Assche <bvanassche@acm.org>
In-Reply-To: <0a44763d-8c40-b9e7-6268-01567c401884@gmail.com>
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On 12/8/22 04:22, Bean Huo wrote:
> 
> On 08.12.22 12:31 AM, Bart Van Assche wrote:
>> On 11/27/22 04:08, Arthur Simchaev wrote:
>>> We used to use the extended-feature field in the device descriptor,
>>> as an indication that the device supports ufs2.2 or later.
>>> Remove that as this check is specifically done few lines above.
>>>
>>> Reviewed-by: Bean Huo <beanhuo@micron.com>
>>> Signed-off-by: Arthur Simchaev <Arthur.Simchaev@wdc.com>
>>> ---
>>>   drivers/ufs/core/ufshcd.c | 4 ----
>>>   1 file changed, 4 deletions(-)
>>>
>>> diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
>>> index 2dbe249..2e47c69 100644
>>> --- a/drivers/ufs/core/ufshcd.c
>>> +++ b/drivers/ufs/core/ufshcd.c
>>> @@ -7608,10 +7608,6 @@ static void ufshcd_wb_probe(struct ufs_hba 
>>> *hba, const u8 *desc_buf)
>>>            (hba->dev_quirks & 
>>> UFS_DEVICE_QUIRK_SUPPORT_EXTENDED_FEATURES)))
>>>           goto wb_disabled;
>>>   -    if (hba->desc_size[QUERY_DESC_IDN_DEVICE] <
>>> -        DEVICE_DESC_PARAM_EXT_UFS_FEATURE_SUP + 4)
>>> -        goto wb_disabled;
>>> -
>>>       ext_ufs_feature = get_unaligned_be32(desc_buf +
>>>                       DEVICE_DESC_PARAM_EXT_UFS_FEATURE_SUP);
>>
>> Does this code really have to be removed? I see a check of the
>> UFS_DEVICE_QUIRK_SUPPORT_EXTENDED_FEATURES flag above the removed
>> code but no check of the descriptor size?
>>
> it is not necessary to check this, but if you have concern, we could 
> change to like this:
> 
> 
>          if (desc_buf[DEVICE_DESC_PARAM_LEN] <
>              DEVICE_DESC_PARAM_EXT_UFS_FEATURE_SUP + 4)
>                  goto wb_disabled;
> 
> then   hba->desc_size could be removed.

Hi Bean,

My only concern is that this patch conflicts with the pending MCQ patch 
series. Since that conflict is unavoidable, let's keep this patch.

Bart.