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Subject: RE: Re: [PATCH v19 2/3] scsi: ufs: L2P map management for HPB read
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Sender: Daejun Park <daejun7.park@samsung.com>
From:   Daejun Park <daejun7.park@samsung.com>
To:     Bean Huo <huobean@gmail.com>, Avri Altman <Avri.Altman@wdc.com>,
        Daejun Park <daejun7.park@samsung.com>,
        Greg KH <gregkh@linuxfoundation.org>,
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        ALIM AKHTAR <alim.akhtar@samsung.com>
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        Sung-Jun Park <sungjun07.park@samsung.com>,
        yongmyung lee <ymhungry.lee@samsung.com>,
        Jinyoung CHOI <j-young.choi@samsung.com>,
        BoRam Shin <boram.shin@samsung.com>,
        SEUNGUK SHIN <seunguk.shin@samsung.com>
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Date:   Mon, 08 Feb 2021 17:00:44 +0900
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> > >"If the requested field of the HPB Region or HPB Sub-Region is out
> > > of
> > > range, then the device shall terminate the command by sending
> > > RESPONSE
> > > UPIU with CHECK CONDITION status, with the SENSE KEY set to ILLEGAL
> > > REQUEST, and the additional sense code set to INVALID FIELD IN CDB"
> > 
> > You don't need to worry about setting invalid ppn to HPB-READ command
> > - 
> > you'll never get a read request for those LBAs.
> > 
> > Say all subregions are 16MB and the last subregion of the last region
> > is 10MB.
> > Keep all sizes the same - 16MB, and the ppn of the last subregion
> > contain some invalid data.
> > But you'll never get a read request for those LBAs anyway - they
> > don't exist,
> > so you'll never get to use those invalid ppns.
> > 
> > Thanks,
> > Avri
>  
> Hi Avri
> ah, I don't know if your above comments are inline with Spec.
>  
> Spec:
> "A HPB Region is divided into HPB Sub-Regions. HPB Sub-Region size is
> specified by the bHPBSubRegionSize parameter of Geometry Descriptor.
> HPB Sub-Regions are equally sized except for the last one which is
> smaller if the last HPB Region is not an interger multiple of
> bHPBSubRegionSize."
>  
> It is not invalidate ppn concern, it is illegal request issue in sense
> key.
>  
> Kind regards,
> Bean

That's a good point.
If the size of the last sub-region is not specified correctly, the map data
cannot be properly fetched. I will support the non-full sized last
sub-region in a new patch.

Thanks,
Daejun