> >>
> >> On 2021-04-06 13:20, Avri Altman wrote:
> >> >> > -static void __ufshpb_evict_region(struct ufshpb_lu *hpb,
> >> >> > -                               struct ufshpb_region *rgn)
> >> >> > +static int __ufshpb_evict_region(struct ufshpb_lu *hpb,
> >> >> > +                              struct ufshpb_region *rgn)
> >> >> >  {
> >> >> >       struct victim_select_info *lru_info;
> >> >> >       struct ufshpb_subregion *srgn;
> >> >> >       int srgn_idx;
> >> >> >
> >> >> > +     lockdep_assert_held(&hpb->rgn_state_lock);
> >> >> > +
> >> >> > +     if (hpb->is_hcm) {
> >> >> > +             unsigned long flags;
> >> >> > +             int ret;
> >> >> > +
> >> >> > +             spin_unlock_irqrestore(&hpb->rgn_state_lock, flags);
> >> >>
> >> >> Never seen a usage like this... Here flags is used without being
> >> >> intialized.
> >> >> The flag is needed when spin_unlock_irqrestore ->
> >> >> local_irq_restore(flags) to
> >> >> restore the DAIF register (in terms of ARM).
> >> > OK.
> >>
> >> Hi Avri,
> >>
> >> Checked on my setup, this lead to compilation error. Will you fix it
> >> in
> >> next version?
> >>
> >> warning: variable 'flags' is uninitialized when used here
> >> [-Wuninitialized]
> > Yeah - I will pass it to __ufshpb_evict_region and drop the
> > lockdep_assert call.
> >
> 
> Please paste the sample code/change here so that I can move forward
> quickly.
Thanks a lot.  Also attaching the patch if its more convenient.

Thanks,
Avri

$ git show 5d33d36e8704
commit 5d33d36e87047d27a546ad3529cb7837186b47b2
Author: Avri Altman <avri.altman@wdc.com>
Date:   Tue Jun 30 15:14:31 2020 +0300

    scsi: ufshpb: Region inactivation in host mode
    
    In host mode, the host is expected to send HPB-WRITE-BUFFER with
    buffer-id = 0x1 when it inactivates a region.
    
    Use the map-requests pool as there is no point in assigning a
    designated cache for umap-requests.
    
    Signed-off-by: Avri Altman <avri.altman@wdc.com>
    Reviewed-by: Daejun Park <daejun7.park@samsung.com>
    Change-Id: I1a6696b38d4abfb4d9fbe44e84016a6238825125

diff --git a/drivers/scsi/ufs/ufshpb.c b/drivers/scsi/ufs/ufshpb.c
index aefb6dc160ee..54a3ea9f5732 100644
--- a/drivers/scsi/ufs/ufshpb.c
+++ b/drivers/scsi/ufs/ufshpb.c
@@ -914,6 +914,7 @@ static int ufshpb_execute_umap_req(struct ufshpb_lu *hpb,
 
        blk_execute_rq_nowait(NULL, req, 1, ufshpb_umap_req_compl_fn);
 
+       hpb->stats.umap_req_cnt++;
        return 0;
 }
 
@@ -1110,18 +1111,35 @@ static int ufshpb_issue_umap_req(struct ufshpb_lu *hpb,
        return -EAGAIN;
 }
 
+static int ufshpb_issue_umap_single_req(struct ufshpb_lu *hpb,
+                                       struct ufshpb_region *rgn)
+{
+       return ufshpb_issue_umap_req(hpb, rgn);
+}
+
 static int ufshpb_issue_umap_all_req(struct ufshpb_lu *hpb)
 {
        return ufshpb_issue_umap_req(hpb, NULL);
 }
 
-static void __ufshpb_evict_region(struct ufshpb_lu *hpb,
-                                 struct ufshpb_region *rgn)
+static int __ufshpb_evict_region(struct ufshpb_lu *hpb,
+                                struct ufshpb_region *rgn,
+                                unsigned long flags)
 {
        struct victim_select_info *lru_info;
        struct ufshpb_subregion *srgn;
        int srgn_idx;
 
+       if (hpb->is_hcm) {
+               int ret;
+
+               spin_unlock_irqrestore(&hpb->rgn_state_lock, flags);
+               ret = ufshpb_issue_umap_single_req(hpb, rgn);
+               spin_lock_irqsave(&hpb->rgn_state_lock, flags);
+               if (ret)
+                       return ret;
+       }
+
        lru_info = &hpb->lru_info;
 
        dev_dbg(&hpb->sdev_ufs_lu->sdev_dev, "evict region %d\n", rgn->rgn_idx);
@@ -1130,6 +1148,8 @@ static void __ufshpb_evict_region(struct ufshpb_lu *hpb,
 
        for_each_sub_region(rgn, srgn_idx, srgn)
                ufshpb_purge_active_subregion(hpb, srgn);
+
+       return 0;
 }
 
 static int ufshpb_evict_region(struct ufshpb_lu *hpb, struct ufshpb_region *rgn)
@@ -1151,7 +1171,7 @@ static int ufshpb_evict_region(struct ufshpb_lu *hpb, struct ufshpb_region *rgn)
                        goto out;
                }
 
-               __ufshpb_evict_region(hpb, rgn);
+               ret = __ufshpb_evict_region(hpb, rgn, flags);
        }
 out:
        spin_unlock_irqrestore(&hpb->rgn_state_lock, flags);
@@ -1285,7 +1305,9 @@ static int ufshpb_add_region(struct ufshpb_lu *hpb, struct ufshpb_region *rgn)
                                "LRU full (%d), choose victim %d\n",
                                atomic_read(&lru_info->active_cnt),
                                victim_rgn->rgn_idx);
-                       __ufshpb_evict_region(hpb, victim_rgn);
+                       ret = __ufshpb_evict_region(hpb, victim_rgn, flags);
+                       if (ret)
+                               goto out;
                }
 
                /*
@@ -1856,6 +1878,7 @@ ufshpb_sysfs_attr_show_func(rb_noti_cnt);
 ufshpb_sysfs_attr_show_func(rb_active_cnt);
 ufshpb_sysfs_attr_show_func(rb_inactive_cnt);
 ufshpb_sysfs_attr_show_func(map_req_cnt);
+ufshpb_sysfs_attr_show_func(umap_req_cnt);
 
 static struct attribute *hpb_dev_stat_attrs[] = {
        &dev_attr_hit_cnt.attr,
@@ -1864,6 +1887,7 @@ static struct attribute *hpb_dev_stat_attrs[] = {
        &dev_attr_rb_active_cnt.attr,
        &dev_attr_rb_inactive_cnt.attr,
        &dev_attr_map_req_cnt.attr,
+       &dev_attr_umap_req_cnt.attr,
        NULL,
 };
 
@@ -1988,6 +2012,7 @@ static void ufshpb_stat_init(struct ufshpb_lu *hpb)
        hpb->stats.rb_active_cnt = 0;
        hpb->stats.rb_inactive_cnt = 0;
        hpb->stats.map_req_cnt = 0;
+       hpb->stats.umap_req_cnt = 0;
 }
 
 static void ufshpb_param_init(struct ufshpb_lu *hpb)
diff --git a/drivers/scsi/ufs/ufshpb.h b/drivers/scsi/ufs/ufshpb.h
index 87495e59fcf1..1ea58c17a4de 100644
--- a/drivers/scsi/ufs/ufshpb.h
+++ b/drivers/scsi/ufs/ufshpb.h
@@ -191,6 +191,7 @@ struct ufshpb_stats {
        u64 rb_inactive_cnt;
        u64 map_req_cnt;
        u64 pre_req_cnt;
+       u64 umap_req_cnt;
 };
 
 struct ufshpb_lu {