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Subject: RE: Re: [PATCH v35 3/4] scsi: ufs: Prepare HPB read for cached
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From:   Daejun Park <daejun7.park@samsung.com>
To:     Bart Van Assche <bvanassche@acm.org>,
        Daejun Park <daejun7.park@samsung.com>,
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        ALIM AKHTAR <alim.akhtar@samsung.com>
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        JinHwan Park <jh.i.park@samsung.com>,
        Javier Gonzalez <javier.gonz@samsung.com>,
        Sung-Jun Park <sungjun07.park@samsung.com>,
        Jinyoung CHOI <j-young.choi@samsung.com>,
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        Jieon Seol <jieon.seol@samsung.com>
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Message-ID: <20210604011124epcms2p39a466db169ebbfd2c889e25fba9aa0b4@epcms2p3>
Date:   Fri, 04 Jun 2021 10:11:24 +0900
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References: <12392bef-e018-8260-5279-16b7b43f5a8f@acm.org>
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Precedence: bulk

Hi Bart,

>> +static void
>> +ufshpb_set_hpb_read_to_upiu(struct ufshpb_lu *hpb, struct ufshcd_lrb *lrbp,
>> +                            u32 lpn, u64 ppn, u8 transfer_len)
>> +{
>> +        unsigned char *cdb = lrbp->cmd->cmnd;
>> +
>> +        cdb[0] = UFSHPB_READ;
>> +
>> +        /* ppn value is stored as big-endian in the host memory */
> 
>I think that that comment means that the type of the 'ppn' argument
>should be changed from 'u64' into __be64.

OK, I will change it.

> 
>> +        memcpy(&cdb[6], &ppn, sizeof(__be64));
>> +        cdb[14] = transfer_len;
>> +
>> +        lrbp->cmd->cmd_len = UFS_CDB_SIZE;
>> +}
>> +
>> +/*
>> + * This function will set up HPB read command using host-side L2P map data.
>> + * In HPB v1.0, maximum size of HPB read command is 4KB.
>> + */
>> +void ufshpb_prep(struct ufs_hba *hba, struct ufshcd_lrb *lrbp)
>> +{
>[ ... ]
>> +
>> +        ufshpb_set_hpb_read_to_upiu(hpb, lrbp, lpn, ppn, transfer_len);
> 
>'transfer_len' has type int and is truncated to type 'u8' when passed as
>an argument to ufshpb_set_hpb_read_to_upiu(). Please handle transfer_len
>values >= 256 properly.

Before entering the function, ufshpb_is_supported_chunk() checks whether
transfer_len <= hpb->pre_req_max_tr_len which is set to
HPB_MULTI_CHUNK_HIGH (128) on initalization.

Thanks,
Daejun