RE: [PATCH v4 7/9] scsi: ufshpb: Add "Cold" regions timer

[Avri Altman]

> 
> Hi Avri,
> 
> > +static void ufshpb_read_to_handler(struct work_struct *work)
> > +{
> > +        struct delayed_work *dwork = to_delayed_work(work);
> > +        struct ufshpb_lu *hpb;
> > +        struct victim_select_info *lru_info;
> > +        struct ufshpb_region *rgn;
> > +        unsigned long flags;
> > +        LIST_HEAD(expired_list);
> > +
> > +        hpb = container_of(dwork, struct ufshpb_lu, ufshpb_read_to_work);
> > +
> > +        if (test_and_set_bit(TIMEOUT_WORK_PENDING, &hpb-
> >work_data_bits))
> > +                return;
> > +
> > +        spin_lock_irqsave(&hpb->rgn_state_lock, flags);
> > +
> > +        lru_info = &hpb->lru_info;
> > +
> > +        list_for_each_entry(rgn, &lru_info->lh_lru_rgn, list_lru_rgn) {
> > +                bool timedout = ktime_after(ktime_get(), rgn->read_timeout);
> > +
> > +                if (timedout) {
> 
> It is important not just to check the timeout, but how much time has passed.
> If the time exceeded is twice the threshold, the read_timeout_expiries
> value should be reduced by 2 instead of 1.
Theoretically this shouldn't happened.
Please note that POLLING_INTERVAL_MS << READ_TO_MS.
Better add appropriate check when making those configurable.

Thanks,
Avri
> 
> > +                        rgn->read_timeout_expiries--;
> 
> Thanks,
> Daejun