RE: Re: [PATCH v26 2/4] scsi: ufs: L2P map management for HPB read

[Daejun Park <daejun7.park@samsung.com>]

> > 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.

OK, I will change it.

Thanks,
Daejun