FROMLIST: scsi: ufs: Region inactivation in HCM

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.

Bug: 183467926
Bug: 170940265
Bug: 183454255

Link: https://lore.kernel.org/lkml/20210607061401.58884-7-avri.altman@wdc.com/
Signed-off-by: Avri Altman <avri.altman@wdc.com>
Change-Id: I1a6696b38d4abfb4d9fbe44e84016a6238825125

drivers/scsi/ufs/ufshpb.c

@@ -693,7 +693,8 @@ int ufshpb_prep(struct ufs_hba *hba, struct ufshcd_lrb *lrbp)
 }
 
 static struct ufshpb_req *ufshpb_get_req(struct ufshpb_lu *hpb,
-					 int rgn_idx, enum req_opf dir)
+					 int rgn_idx, enum req_opf dir,
+					 bool atomic)
 {
 	struct ufshpb_req *rq;
 	struct request *req;
@@ -707,7 +708,7 @@ retry:
 	req = blk_get_request(hpb->sdev_ufs_lu->request_queue, dir,
 			      BLK_MQ_REQ_NOWAIT);
 
-	if ((PTR_ERR(req) == -EWOULDBLOCK) && (--retries > 0)) {
+	if (!atomic && (PTR_ERR(req) == -EWOULDBLOCK) && (--retries > 0)) {
 		usleep_range(3000, 3100);
 		goto retry;
 	}
@@ -738,7 +739,7 @@ static struct ufshpb_req *ufshpb_get_map_req(struct ufshpb_lu *hpb,
 	struct ufshpb_req *map_req;
 	struct bio *bio;
 
-	map_req = ufshpb_get_req(hpb, srgn->rgn_idx, REQ_OP_SCSI_IN);
+	map_req = ufshpb_get_req(hpb, srgn->rgn_idx, REQ_OP_SCSI_IN, false);
 	if (!map_req)
 		return NULL;
 
@@ -915,6 +916,8 @@ static void ufshpb_execute_umap_req(struct ufshpb_lu *hpb,
 	rq->cmd_len = HPB_WRITE_BUFFER_CMD_LENGTH;
 
 	blk_execute_rq_nowait(req->q, NULL, req, 1, ufshpb_umap_req_compl_fn);
+
+	hpb->stats.umap_req_cnt++;
 }
 
 static int ufshpb_execute_map_req(struct ufshpb_lu *hpb,
@@ -1091,12 +1094,13 @@ static void ufshpb_purge_active_subregion(struct ufshpb_lu *hpb,
 }
 
 static int ufshpb_issue_umap_req(struct ufshpb_lu *hpb,
-				 struct ufshpb_region *rgn)
+				 struct ufshpb_region *rgn,
+				 bool atomic)
 {
 	struct ufshpb_req *umap_req;
 	int rgn_idx = rgn ? rgn->rgn_idx : 0;
 
-	umap_req = ufshpb_get_req(hpb, rgn_idx, REQ_OP_SCSI_OUT);
+	umap_req = ufshpb_get_req(hpb, rgn_idx, REQ_OP_SCSI_OUT, atomic);
 	if (!umap_req)
 		return -ENOMEM;
 
@@ -1105,13 +1109,19 @@ static int ufshpb_issue_umap_req(struct ufshpb_lu *hpb,
 	return 0;
 }
 
+static int ufshpb_issue_umap_single_req(struct ufshpb_lu *hpb,
+					struct ufshpb_region *rgn)
+{
+	return ufshpb_issue_umap_req(hpb, rgn, true);
+}
+
 static int ufshpb_issue_umap_all_req(struct ufshpb_lu *hpb)
 {
-	return ufshpb_issue_umap_req(hpb, NULL);
+	return ufshpb_issue_umap_req(hpb, NULL, false);
 }
 
 static void __ufshpb_evict_region(struct ufshpb_lu *hpb,
-				  struct ufshpb_region *rgn)
+				 struct ufshpb_region *rgn)
 {
 	struct victim_select_info *lru_info;
 	struct ufshpb_subregion *srgn;
@@ -1145,6 +1155,14 @@ static int ufshpb_evict_region(struct ufshpb_lu *hpb, struct ufshpb_region *rgn)
 			goto out;
 		}
 
+		if (hpb->is_hcm) {
+			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)
+				goto out;
+		}
+
 		__ufshpb_evict_region(hpb, rgn);
 	}
 out:
@@ -1279,6 +1297,18 @@ 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);
+
+			if (hpb->is_hcm) {
+				spin_unlock_irqrestore(&hpb->rgn_state_lock,
+						       flags);
+				ret = ufshpb_issue_umap_single_req(hpb,
+								victim_rgn);
+				spin_lock_irqsave(&hpb->rgn_state_lock,
+						  flags);
+				if (ret)
+					goto out;
+			}
+
 			__ufshpb_evict_region(hpb, victim_rgn);
 		}
 
@@ -1849,6 +1879,7 @@ 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,
@@ -1857,6 +1888,7 @@ 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,
 };
 
@@ -1982,6 +2014,7 @@ 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)

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 {