RE: [PATCH v5 08/10] scsi: ufshpb: Limit the number of inflight map requests

[Avri Altman <Avri.Altman@wdc.com>]

> 
> 
> On 2021-03-02 21:25, Avri Altman wrote:
> > in host control mode the host is the originator of map requests. To not
> 
> in -> In
Done.

> 
> Thanks,
> Can Guo.
> 
> > flood the device with map requests, use a simple throttling mechanism
> > that limits the number of inflight map requests.
> >
> > Signed-off-by: Avri Altman <avri.altman@wdc.com>
> > ---
> >  drivers/scsi/ufs/ufshpb.c | 11 +++++++++++
> >  drivers/scsi/ufs/ufshpb.h |  1 +
> >  2 files changed, 12 insertions(+)
> >
> > diff --git a/drivers/scsi/ufs/ufshpb.c b/drivers/scsi/ufs/ufshpb.c
> > index 89a930e72cff..74da69727340 100644
> > --- a/drivers/scsi/ufs/ufshpb.c
> > +++ b/drivers/scsi/ufs/ufshpb.c
> > @@ -21,6 +21,7 @@
> >  #define READ_TO_MS 1000
> >  #define READ_TO_EXPIRIES 100
> >  #define POLLING_INTERVAL_MS 200
> > +#define THROTTLE_MAP_REQ_DEFAULT 1
> >
> >  /* memory management */
> >  static struct kmem_cache *ufshpb_mctx_cache;
> > @@ -750,6 +751,14 @@ static struct ufshpb_req
> > *ufshpb_get_map_req(struct ufshpb_lu *hpb,
> >       struct ufshpb_req *map_req;
> >       struct bio *bio;
> >
> > +     if (hpb->is_hcm &&
> > +         hpb->num_inflight_map_req >= THROTTLE_MAP_REQ_DEFAULT) {
> > +             dev_info(&hpb->sdev_ufs_lu->sdev_dev,
> > +                      "map_req throttle. inflight %d throttle %d",
> > +                      hpb->num_inflight_map_req, THROTTLE_MAP_REQ_DEFAULT);
> > +             return NULL;
> > +     }
> > +
> >       map_req = ufshpb_get_req(hpb, srgn->rgn_idx, REQ_OP_SCSI_IN);
> >       if (!map_req)
> >               return NULL;
> > @@ -764,6 +773,7 @@ static struct ufshpb_req
> > *ufshpb_get_map_req(struct ufshpb_lu *hpb,
> >
> >       map_req->rb.srgn_idx = srgn->srgn_idx;
> >       map_req->rb.mctx = srgn->mctx;
> > +     hpb->num_inflight_map_req++;
> >
> >       return map_req;
> >  }
> > @@ -773,6 +783,7 @@ static void ufshpb_put_map_req(struct ufshpb_lu
> > *hpb,
> >  {
> >       bio_put(map_req->bio);
> >       ufshpb_put_req(hpb, map_req);
> > +     hpb->num_inflight_map_req--;
> >  }
> >
> >  static int ufshpb_clear_dirty_bitmap(struct ufshpb_lu *hpb,
> > diff --git a/drivers/scsi/ufs/ufshpb.h b/drivers/scsi/ufs/ufshpb.h
> > index b49e9a34267f..d83ab488688a 100644
> > --- a/drivers/scsi/ufs/ufshpb.h
> > +++ b/drivers/scsi/ufs/ufshpb.h
> > @@ -212,6 +212,7 @@ struct ufshpb_lu {
> >       struct ufshpb_req *pre_req;
> >       int num_inflight_pre_req;
> >       int throttle_pre_req;
> > +     int num_inflight_map_req;
> >       struct list_head lh_pre_req_free;
> >       int cur_read_id;
> >       int pre_req_min_tr_len;