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Message-ID: <0a44763d-8c40-b9e7-6268-01567c401884@gmail.com>
Date:   Thu, 8 Dec 2022 13:22:15 +0100
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Subject: Re: [PATCH v4 1/4] ufs: core: Remove redundant wb check
To:     Bart Van Assche <bvanassche@acm.org>,
        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>
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From:   Bean Huo <huobean@gmail.com>
In-Reply-To: <b89f3337-0869-35a8-114d-85e1fd81eb2c@acm.org>
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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.

Kind regards,

Bean