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Date:   Fri, 12 Mar 2021 09:19:58 +0800
From:   Can Guo <cang@codeaurora.org>
To:     daejun7.park@samsung.com
Cc:     Greg KH <gregkh@linuxfoundation.org>, avri.altman@wdc.com,
        jejb@linux.ibm.com, martin.petersen@oracle.com,
        asutoshd@codeaurora.org, stanley.chu@mediatek.com,
        bvanassche@acm.org, huobean@gmail.com,
        ALIM AKHTAR <alim.akhtar@samsung.com>,
        linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
        JinHwan Park <jh.i.park@samsung.com>,
        Javier Gonzalez <javier.gonz@samsung.com>,
        SEUNGUK SHIN <seunguk.shin@samsung.com>,
        Sung-Jun Park <sungjun07.park@samsung.com>,
        Jinyoung CHOI <j-young.choi@samsung.com>,
        BoRam Shin <boram.shin@samsung.com>
Subject: Re: [PATCH v26 2/4] scsi: ufs: L2P map management for HPB read
In-Reply-To: <20210303062829epcms2p678450953f611c340a2b8e88b5542fe73@epcms2p6>
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 <CGME20210303062633epcms2p252227acd30ad15c1ca821d7e3f547b9e@epcms2p6>
 <20210303062829epcms2p678450953f611c340a2b8e88b5542fe73@epcms2p6>
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On 2021-03-03 14:28, Daejun Park wrote:
> This is a patch for managing L2P map in HPB module.
> 
> The HPB divides logical addresses into several regions. A region 
> consists
> of several sub-regions. The sub-region is a basic unit where L2P 
> mapping is
> managed. The driver loads L2P mapping data of each sub-region. The 
> loaded
> sub-region is called active-state. The HPB driver unloads L2P mapping 
> data
> as region unit. The unloaded region is called inactive-state.
> 
> Sub-region/region candidates to be loaded and unloaded are delivered 
> from
> the UFS device. The UFS device delivers the recommended active 
> sub-region
> and inactivate region to the driver using sensedata.
> The HPB module performs L2P mapping management on the host through the
> delivered information.
> 
> A pinned region is a pre-set regions on the UFS device that is always
> activate-state.
> 
> The data structure for map data request and L2P map uses mempool API,
> minimizing allocation overhead while avoiding static allocation.
> 
> The mininum size of the memory pool used in the HPB is implemented
> as a module parameter, so that it can be configurable by the user.
> 
> To gurantee a minimum memory pool size of 4MB: 
> ufshpb_host_map_kbytes=4096
> 
> The map_work manages active/inactive by 2 "to-do" lists.
> Each hpb lun maintains 2 "to-do" lists:
>   hpb->lh_inact_rgn - regions to be inactivated, and
>   hpb->lh_act_srgn - subregions to be activated
> Those lists are maintained on IO completion.
> 
> Reviewed-by: Bart Van Assche <bvanassche@acm.org>
> Reviewed-by: Can Guo <cang@codeaurora.org>
> Acked-by: Avri Altman <Avri.Altman@wdc.com>
> Tested-by: Bean Huo <beanhuo@micron.com>
> Signed-off-by: Daejun Park <daejun7.park@samsung.com>
> ---
>  drivers/scsi/ufs/ufs.h    |   36 ++
>  drivers/scsi/ufs/ufshcd.c |    4 +
>  drivers/scsi/ufs/ufshpb.c | 1091 ++++++++++++++++++++++++++++++++++++-
>  drivers/scsi/ufs/ufshpb.h |   65 +++
>  4 files changed, 1181 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/scsi/ufs/ufs.h b/drivers/scsi/ufs/ufs.h
> index 65563635e20e..957763db1006 100644
> --- a/drivers/scsi/ufs/ufs.h
> +++ b/drivers/scsi/ufs/ufs.h
> @@ -472,6 +472,41 @@ struct utp_cmd_rsp {
>  	u8 sense_data[UFS_SENSE_SIZE];
>  };
> ...
> +/*
> + * This function will parse recommended active subregion information 
> in sense
> + * data field of response UPIU with SAM_STAT_GOOD state.
> + */
> +void ufshpb_rsp_upiu(struct ufs_hba *hba, struct ufshcd_lrb *lrbp)
> +{
> +	struct ufshpb_lu *hpb = ufshpb_get_hpb_data(lrbp->cmd->device);
> +	struct utp_hpb_rsp *rsp_field = &lrbp->ucd_rsp_ptr->hr;
> +	int data_seg_len;
> +
> +	if (unlikely(lrbp->lun != rsp_field->lun)) {
> +		struct scsi_device *sdev;
> +		bool found = false;
> +
> +		__shost_for_each_device(sdev, hba->host) {
> +			hpb = ufshpb_get_hpb_data(sdev);
> +
> +			if (!hpb)
> +				continue;
> +
> +			if (rsp_field->lun == hpb->lun) {
> +				found = true;
> +				break;
> +			}
> +		}
> +
> +		if (!found)
> +			return;
> +	}
> +
> +	if (!hpb)
> +		return;
> +
> +	if ((ufshpb_get_state(hpb) != HPB_PRESENT) &&
> +	    (ufshpb_get_state(hpb) != HPB_SUSPEND)) {
> +		dev_notice(&hpb->sdev_ufs_lu->sdev_dev,
> +			   "%s: ufshpb state is not PRESENT/SUSPEND\n",
> +			   __func__);

Please mute these prints before hpb is fully initilized, otherwise
there can be tons of these prints during bootup. Say set a flag in
ufshpb_hpb_lu_prepared() and check for that flag - just a rough idea.

Thanks,
Can Guo.

> +		return;
> +	}
> +