UBI: harmonize the update of ubi->beb_rsvd_pebs

Currently, there are several locations where an attempt to reserve more
PEBs for bad PEB handling is made, with the same code being duplicated.

Harmonize it by introducing 'ubi_update_reserved()'.

Also, improve the debug message issued, making it more descriptive.

Artem: amended the patch a little.
Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@linux.intel.com>

drivers/mtd/ubi/misc.c

@@ -91,6 +91,29 @@ int ubi_check_volume(struct ubi_device *ubi, int vol_id)
 	return err;
 }
 
+/**
+ * ubi_update_reserved - update bad eraseblock handling accounting data.
+ * @ubi: UBI device description object
+ *
+ * This function calculates the gap between current number of PEBs reserved for
+ * bad eraseblock handling and the required level of PEBs that must be
+ * reserved, and if necessary, reserves more PEBs to fill that gap, according
+ * to availability. Should be called with ubi->volumes_lock held.
+ */
+void ubi_update_reserved(struct ubi_device *ubi)
+{
+	int need = ubi->beb_rsvd_level - ubi->beb_rsvd_pebs;
+
+	if (need <= 0 || ubi->avail_pebs == 0)
+		return;
+
+	need = min_t(int, need, ubi->avail_pebs);
+	ubi->avail_pebs -= need;
+	ubi->rsvd_pebs += need;
+	ubi->beb_rsvd_pebs += need;
+	ubi_msg("reserved more %d PEBs for bad PEB handling", need);
+}
+
 /**
  * ubi_calculate_reserved - calculate how many PEBs must be reserved for bad
  * eraseblock handling.

drivers/mtd/ubi/ubi.h

@@ -647,6 +647,7 @@ int ubi_more_leb_change_data(struct ubi_device *ubi, struct ubi_volume *vol,
 int ubi_calc_data_len(const struct ubi_device *ubi, const void *buf,
 		      int length);
 int ubi_check_volume(struct ubi_device *ubi, int vol_id);
+void ubi_update_reserved(struct ubi_device *ubi);
 void ubi_calculate_reserved(struct ubi_device *ubi);
 int ubi_check_pattern(const void *buf, uint8_t patt, int size);
 

drivers/mtd/ubi/vmt.c

@@ -443,15 +443,7 @@ int ubi_remove_volume(struct ubi_volume_desc *desc, int no_vtbl)
 	spin_lock(&ubi->volumes_lock);
 	ubi->rsvd_pebs -= reserved_pebs;
 	ubi->avail_pebs += reserved_pebs;
-	i = ubi->beb_rsvd_level - ubi->beb_rsvd_pebs;
-	if (i > 0) {
-		i = ubi->avail_pebs >= i ? i : ubi->avail_pebs;
-		ubi->avail_pebs -= i;
-		ubi->rsvd_pebs += i;
-		ubi->beb_rsvd_pebs += i;
-		if (i > 0)
-			ubi_msg("reserve more %d PEBs", i);
-	}
+	ubi_update_reserved(ubi);
 	ubi->vol_count -= 1;
 	spin_unlock(&ubi->volumes_lock);
 
@@ -558,15 +550,7 @@ int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs)
 		spin_lock(&ubi->volumes_lock);
 		ubi->rsvd_pebs += pebs;
 		ubi->avail_pebs -= pebs;
-		pebs = ubi->beb_rsvd_level - ubi->beb_rsvd_pebs;
-		if (pebs > 0) {
-			pebs = ubi->avail_pebs >= pebs ? pebs : ubi->avail_pebs;
-			ubi->avail_pebs -= pebs;
-			ubi->rsvd_pebs += pebs;
-			ubi->beb_rsvd_pebs += pebs;
-			if (pebs > 0)
-				ubi_msg("reserve more %d PEBs", pebs);
-		}
+		ubi_update_reserved(ubi);
 		for (i = 0; i < reserved_pebs; i++)
 			new_mapping[i] = vol->eba_tbl[i];
 		kfree(vol->eba_tbl);