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From:   Avri Altman <Avri.Altman@wdc.com>
To:     Can Guo <cang@codeaurora.org>
CC:     "James E . J . Bottomley" <jejb@linux.vnet.ibm.com>,
        "Martin K . Petersen" <martin.petersen@oracle.com>,
        "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
        Bart Van Assche <bvanassche@acm.org>,
        yongmyung lee <ymhungry.lee@samsung.com>,
        Daejun Park <daejun7.park@samsung.com>,
        "alim.akhtar@samsung.com" <alim.akhtar@samsung.com>,
        "asutoshd@codeaurora.org" <asutoshd@codeaurora.org>,
        Zang Leigang <zangleigang@hisilicon.com>,
        Avi Shchislowski <Avi.Shchislowski@wdc.com>,
        Bean Huo <beanhuo@micron.com>,
        "stanley.chu@mediatek.com" <stanley.chu@mediatek.com>
Subject: RE: [PATCH v5 06/10] scsi: ufshpb: Add hpb dev reset response
Thread-Topic: [PATCH v5 06/10] scsi: ufshpb: Add hpb dev reset response
Thread-Index: AQHXD2ex1y1f5g2rP02e5lIjKmzR26qIGY0AgAAGPJCAAA7hAIAAAEIA
Date:   Wed, 17 Mar 2021 12:22:15 +0000
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>=20
> On 2021-03-17 19:23, Avri Altman wrote:
> >>
> >> On 2021-03-02 21:24, Avri Altman wrote:
> >> > The spec does not define what is the host's recommended response whe=
n
> >> > the device send hpb dev reset response (oper 0x2).
> >> >
> >> > We will update all active hpb regions: mark them and do that on the
> >> > next
> >> > read.
> >> >
> >> > Signed-off-by: Avri Altman <avri.altman@wdc.com>
> >> > ---
> >> >  drivers/scsi/ufs/ufshpb.c | 47
> >> ++++++++++++++++++++++++++++++++++++---
> >> >  drivers/scsi/ufs/ufshpb.h |  2 ++
> >> >  2 files changed, 46 insertions(+), 3 deletions(-)
> >> >
> >> > diff --git a/drivers/scsi/ufs/ufshpb.c b/drivers/scsi/ufs/ufshpb.c
> >> > index 0744feb4d484..0034fa03fdc6 100644
> >> > --- a/drivers/scsi/ufs/ufshpb.c
> >> > +++ b/drivers/scsi/ufs/ufshpb.c
> >> > @@ -642,7 +642,8 @@ int ufshpb_prep(struct ufs_hba *hba, struct
> >> > ufshcd_lrb *lrbp)
> >> >               if (rgn->reads =3D=3D ACTIVATION_THRESHOLD)
> >> >                       activate =3D true;
> >> >               spin_unlock_irqrestore(&rgn->rgn_lock, flags);
> >> > -             if (activate) {
> >> > +             if (activate ||
> >> > +                 test_and_clear_bit(RGN_FLAG_UPDATE, &rgn->rgn_flag=
s)) {
> >> >                       spin_lock_irqsave(&hpb->rsp_list_lock, flags);
> >> >                       ufshpb_update_active_info(hpb, rgn_idx, srgn_i=
dx);
> >> >                       hpb->stats.rb_active_cnt++;
> >> > @@ -1480,6 +1481,20 @@ void ufshpb_rsp_upiu(struct ufs_hba *hba,
> >> > struct ufshcd_lrb *lrbp)
> >> >       case HPB_RSP_DEV_RESET:
> >> >               dev_warn(&hpb->sdev_ufs_lu->sdev_dev,
> >> >                        "UFS device lost HPB information during PM.\n=
");
> >> > +
> >> > +             if (hpb->is_hcm) {
> >> > +                     struct scsi_device *sdev;
> >> > +
> >> > +                     __shost_for_each_device(sdev, hba->host) {
> >> > +                             struct ufshpb_lu *h =3D sdev->hostdata=
;
> >> > +
> >> > +                             if (!h)
> >> > +                                     continue;
> >> > +
> >> > +                             schedule_work(&hpb->ufshpb_lun_reset_w=
ork);
> >> > +                     }
> >> > +             }
> >> > +
> >> >               break;
> >> >       default:
> >> >               dev_notice(&hpb->sdev_ufs_lu->sdev_dev,
> >> > @@ -1594,6 +1609,25 @@ static void
> >> > ufshpb_run_inactive_region_list(struct ufshpb_lu *hpb)
> >> >       spin_unlock_irqrestore(&hpb->rsp_list_lock, flags);
> >> >  }
> >> >
> >> > +static void ufshpb_reset_work_handler(struct work_struct *work)
> >>
> >> Just curious, directly doing below things inside ufshpb_rsp_upiu()
> >> does
> >> not
> >> seem a problem to me, does this really deserve a separate work?
> > I don't know, I never even consider of doing this.
> > The active region list may contain up to few thousands of regions -
> > It is not rare to see configurations that covers the entire device.
> >
>=20
> Yes, true, it can be a huge list. But what does the ops
> "HPB_RSP_DEV_RESET"
> really mean? The specs says "Device reset HPB Regions information", but
> I
> don't know what is really happening. Could you please elaborate?
It means that the device informs the host that the L2P cache is no longer v=
alid.
The spec doesn't say what to do in that case.
We thought that in host mode, it make sense to update all the active region=
s.

I think I will go with your suggestion.
Effectively, in host mode, since it is deactivating "cold" regions,
the lru list is kept relatively small, and contains only "hot" regions.

Thanks,
Avri

>=20
> Thanks,
> Can Guo.
>=20
> > But yes, I can do that.
> > Better to get ack from Daejun first.
> >
> > Thanks,
> > Avri
> >
> >>
> >> Thanks,
> >> Can Guo.
> >>
> >> > +{
> >> > +     struct ufshpb_lu *hpb;
> >> > +     struct victim_select_info *lru_info;
> >> > +     struct ufshpb_region *rgn;
> >> > +     unsigned long flags;
> >> > +
> >> > +     hpb =3D container_of(work, struct ufshpb_lu, ufshpb_lun_reset_=
work);
> >> > +
> >> > +     lru_info =3D &hpb->lru_info;
> >> > +
> >> > +     spin_lock_irqsave(&hpb->rgn_state_lock, flags);
> >> > +
> >> > +     list_for_each_entry(rgn, &lru_info->lh_lru_rgn, list_lru_rgn)
> >> > +             set_bit(RGN_FLAG_UPDATE, &rgn->rgn_flags);
> >> > +
> >> > +     spin_unlock_irqrestore(&hpb->rgn_state_lock, flags);
> >> > +}
> >> > +
> >> >  static void ufshpb_normalization_work_handler(struct work_struct
> >> > *work)
> >> >  {
> >> >       struct ufshpb_lu *hpb;
> >> > @@ -1798,6 +1832,8 @@ static int ufshpb_alloc_region_tbl(struct
> >> > ufs_hba *hba, struct ufshpb_lu *hpb)
> >> >               } else {
> >> >                       rgn->rgn_state =3D HPB_RGN_INACTIVE;
> >> >               }
> >> > +
> >> > +             rgn->rgn_flags =3D 0;
> >> >       }
> >> >
> >> >       return 0;
> >> > @@ -2012,9 +2048,12 @@ static int ufshpb_lu_hpb_init(struct ufs_hba
> >> > *hba, struct ufshpb_lu *hpb)
> >> >       INIT_LIST_HEAD(&hpb->list_hpb_lu);
> >> >
> >> >       INIT_WORK(&hpb->map_work, ufshpb_map_work_handler);
> >> > -     if (hpb->is_hcm)
> >> > +     if (hpb->is_hcm) {
> >> >               INIT_WORK(&hpb->ufshpb_normalization_work,
> >> >                         ufshpb_normalization_work_handler);
> >> > +             INIT_WORK(&hpb->ufshpb_lun_reset_work,
> >> > +                       ufshpb_reset_work_handler);
> >> > +     }
> >> >
> >> >       hpb->map_req_cache =3D kmem_cache_create("ufshpb_req_cache",
> >> >                         sizeof(struct ufshpb_req), 0, 0, NULL);
> >> > @@ -2114,8 +2153,10 @@ static void ufshpb_discard_rsp_lists(struct
> >> > ufshpb_lu *hpb)
> >> >
> >> >  static void ufshpb_cancel_jobs(struct ufshpb_lu *hpb)
> >> >  {
> >> > -     if (hpb->is_hcm)
> >> > +     if (hpb->is_hcm) {
> >> > +             cancel_work_sync(&hpb->ufshpb_lun_reset_work);
> >> >               cancel_work_sync(&hpb->ufshpb_normalization_work);
> >> > +     }
> >> >       cancel_work_sync(&hpb->map_work);
> >> >  }
> >> >
> >> > diff --git a/drivers/scsi/ufs/ufshpb.h b/drivers/scsi/ufs/ufshpb.h
> >> > index 84598a317897..37c1b0ea0c0a 100644
> >> > --- a/drivers/scsi/ufs/ufshpb.h
> >> > +++ b/drivers/scsi/ufs/ufshpb.h
> >> > @@ -121,6 +121,7 @@ struct ufshpb_region {
> >> >       struct list_head list_lru_rgn;
> >> >       unsigned long rgn_flags;
> >> >  #define RGN_FLAG_DIRTY 0
> >> > +#define RGN_FLAG_UPDATE 1
> >> >
> >> >       /* region reads - for host mode */
> >> >       spinlock_t rgn_lock;
> >> > @@ -217,6 +218,7 @@ struct ufshpb_lu {
> >> >       /* for selecting victim */
> >> >       struct victim_select_info lru_info;
> >> >       struct work_struct ufshpb_normalization_work;
> >> > +     struct work_struct ufshpb_lun_reset_work;
> >> >
> >> >       /* pinned region information */
> >> >       u32 lu_pinned_start;