diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index b85ca186afc6..5d00364d4a4a 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -249,7 +249,7 @@ static void kill_volumes(struct ubi_device *ubi)
 
 	for (i = 0; i < ubi->vtbl_slots; i++)
 		if (ubi->volumes[i])
-			ubi_free_volume(ubi, i);
+			ubi_free_volume(ubi, ubi->volumes[i]);
 }
 
 /**
@@ -300,7 +300,7 @@ static int uif_init(struct ubi_device *ubi)
 
 	for (i = 0; i < ubi->vtbl_slots; i++)
 		if (ubi->volumes[i]) {
-			err = ubi_add_volume(ubi, i);
+			err = ubi_add_volume(ubi, ubi->volumes[i]);
 			if (err) {
 				ubi_err("cannot add volume %d", i);
 				goto out_volumes;
diff --git a/drivers/mtd/ubi/cdev.c b/drivers/mtd/ubi/cdev.c
index 7697eda2d58c..24344ba3cfed 100644
--- a/drivers/mtd/ubi/cdev.c
+++ b/drivers/mtd/ubi/cdev.c
@@ -249,7 +249,7 @@ static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
 		if (off + len >= vol->usable_leb_size)
 			len = vol->usable_leb_size - off;
 
-		err = ubi_eba_read_leb(ubi, vol_id, lnum, tbuf, off, len, 0);
+		err = ubi_eba_read_leb(ubi, vol, lnum, tbuf, off, len, 0);
 		if (err)
 			break;
 
@@ -339,7 +339,7 @@ static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
 			break;
 		}
 
-		err = ubi_eba_write_leb(ubi, vol_id, lnum, tbuf, off, len,
+		err = ubi_eba_write_leb(ubi, vol, lnum, tbuf, off, len,
 					UBI_UNKNOWN);
 		if (err)
 			break;
@@ -484,7 +484,7 @@ static int vol_cdev_ioctl(struct inode *inode, struct file *file,
 		}
 
 		dbg_msg("erase LEB %d:%d", vol->vol_id, lnum);
-		err = ubi_eba_unmap_leb(ubi, vol->vol_id, lnum);
+		err = ubi_eba_unmap_leb(ubi, vol, lnum);
 		if (err)
 			break;
 
diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
index 5fdb31bc5636..b2b0f29bdc53 100644
--- a/drivers/mtd/ubi/eba.c
+++ b/drivers/mtd/ubi/eba.c
@@ -289,17 +289,17 @@ static void leb_write_unlock(struct ubi_device *ubi, int vol_id, int lnum)
 /**
  * ubi_eba_unmap_leb - un-map logical eraseblock.
  * @ubi: UBI device description object
- * @vol_id: volume ID
+ * @vol: volume description object
  * @lnum: logical eraseblock number
  *
  * This function un-maps logical eraseblock @lnum and schedules corresponding
  * physical eraseblock for erasure. Returns zero in case of success and a
  * negative error code in case of failure.
  */
-int ubi_eba_unmap_leb(struct ubi_device *ubi, int vol_id, int lnum)
+int ubi_eba_unmap_leb(struct ubi_device *ubi, struct ubi_volume *vol,
+		      int lnum)
 {
-	int idx = vol_id2idx(ubi, vol_id), err, pnum;
-	struct ubi_volume *vol = ubi->volumes[idx];
+	int err, pnum, vol_id = vol->vol_id;
 
 	if (ubi->ro_mode)
 		return -EROFS;
@@ -326,7 +326,7 @@ int ubi_eba_unmap_leb(struct ubi_device *ubi, int vol_id, int lnum)
 /**
  * ubi_eba_read_leb - read data.
  * @ubi: UBI device description object
- * @vol_id: volume ID
+ * @vol: volume description object
  * @lnum: logical eraseblock number
  * @buf: buffer to store the read data
  * @offset: offset from where to read
@@ -342,12 +342,11 @@ int ubi_eba_unmap_leb(struct ubi_device *ubi, int vol_id, int lnum)
  * returned for any volume type if an ECC error was detected by the MTD device
  * driver. Other negative error cored may be returned in case of other errors.
  */
-int ubi_eba_read_leb(struct ubi_device *ubi, int vol_id, int lnum, void *buf,
-		     int offset, int len, int check)
+int ubi_eba_read_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
+		     void *buf, int offset, int len, int check)
 {
-	int err, pnum, scrub = 0, idx = vol_id2idx(ubi, vol_id);
+	int err, pnum, scrub = 0, vol_id = vol->vol_id;
 	struct ubi_vid_hdr *vid_hdr;
-	struct ubi_volume *vol = ubi->volumes[idx];
 	uint32_t uninitialized_var(crc);
 
 	err = leb_read_lock(ubi, vol_id, lnum);
@@ -555,7 +554,7 @@ static int recover_peb(struct ubi_device *ubi, int pnum, int vol_id, int lnum,
 /**
  * ubi_eba_write_leb - write data to dynamic volume.
  * @ubi: UBI device description object
- * @vol_id: volume ID
+ * @vol: volume description object
  * @lnum: logical eraseblock number
  * @buf: the data to write
  * @offset: offset within the logical eraseblock where to write
@@ -563,15 +562,14 @@ static int recover_peb(struct ubi_device *ubi, int pnum, int vol_id, int lnum,
  * @dtype: data type
  *
  * This function writes data to logical eraseblock @lnum of a dynamic volume
- * @vol_id. Returns zero in case of success and a negative error code in case
+ * @vol. Returns zero in case of success and a negative error code in case
  * of failure. In case of error, it is possible that something was still
  * written to the flash media, but may be some garbage.
  */
-int ubi_eba_write_leb(struct ubi_device *ubi, int vol_id, int lnum,
+int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
 		      const void *buf, int offset, int len, int dtype)
 {
-	int idx = vol_id2idx(ubi, vol_id), err, pnum, tries = 0;
-	struct ubi_volume *vol = ubi->volumes[idx];
+	int err, pnum, tries = 0, vol_id = vol->vol_id;
 	struct ubi_vid_hdr *vid_hdr;
 
 	if (ubi->ro_mode)
@@ -590,7 +588,8 @@ int ubi_eba_write_leb(struct ubi_device *ubi, int vol_id, int lnum,
 		if (err) {
 			ubi_warn("failed to write data to PEB %d", pnum);
 			if (err == -EIO && ubi->bad_allowed)
-				err = recover_peb(ubi, pnum, vol_id, lnum, buf, offset, len);
+				err = recover_peb(ubi, pnum, vol_id, lnum, buf,
+						  offset, len);
 			if (err)
 				ubi_ro_mode(ubi);
 		}
@@ -678,7 +677,7 @@ int ubi_eba_write_leb(struct ubi_device *ubi, int vol_id, int lnum,
 /**
  * ubi_eba_write_leb_st - write data to static volume.
  * @ubi: UBI device description object
- * @vol_id: volume ID
+ * @vol: volume description object
  * @lnum: logical eraseblock number
  * @buf: data to write
  * @len: how many bytes to write
@@ -686,7 +685,7 @@ int ubi_eba_write_leb(struct ubi_device *ubi, int vol_id, int lnum,
  * @used_ebs: how many logical eraseblocks will this volume contain
  *
  * This function writes data to logical eraseblock @lnum of static volume
- * @vol_id. The @used_ebs argument should contain total number of logical
+ * @vol. The @used_ebs argument should contain total number of logical
  * eraseblock in this static volume.
  *
  * When writing to the last logical eraseblock, the @len argument doesn't have
@@ -698,12 +697,11 @@ int ubi_eba_write_leb(struct ubi_device *ubi, int vol_id, int lnum,
  * volumes. This function returns zero in case of success and a negative error
  * code in case of failure.
  */
-int ubi_eba_write_leb_st(struct ubi_device *ubi, int vol_id, int lnum,
-			 const void *buf, int len, int dtype, int used_ebs)
+int ubi_eba_write_leb_st(struct ubi_device *ubi, struct ubi_volume *vol,
+			 int lnum, const void *buf, int len, int dtype,
+			 int used_ebs)
 {
-	int err, pnum, tries = 0, data_size = len;
-	int idx = vol_id2idx(ubi, vol_id);
-	struct ubi_volume *vol = ubi->volumes[idx];
+	int err, pnum, tries = 0, data_size = len, vol_id = vol->vol_id;
 	struct ubi_vid_hdr *vid_hdr;
 	uint32_t crc;
 
@@ -799,7 +797,7 @@ int ubi_eba_write_leb_st(struct ubi_device *ubi, int vol_id, int lnum,
 /*
  * ubi_eba_atomic_leb_change - change logical eraseblock atomically.
  * @ubi: UBI device description object
- * @vol_id: volume ID
+ * @vol: volume escription object
  * @lnum: logical eraseblock number
  * @buf: data to write
  * @len: how many bytes to write
@@ -814,11 +812,10 @@ int ubi_eba_write_leb_st(struct ubi_device *ubi, int vol_id, int lnum,
  * UBI reserves one LEB for the "atomic LEB change" operation, so only one
  * LEB change may be done at a time. This is ensured by @ubi->alc_mutex.
  */
-int ubi_eba_atomic_leb_change(struct ubi_device *ubi, int vol_id, int lnum,
-			      const void *buf, int len, int dtype)
+int ubi_eba_atomic_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
+			      int lnum, const void *buf, int len, int dtype)
 {
-	int err, pnum, tries = 0, idx = vol_id2idx(ubi, vol_id);
-	struct ubi_volume *vol = ubi->volumes[idx];
+	int err, pnum, tries = 0, vol_id = vol->vol_id;
 	struct ubi_vid_hdr *vid_hdr;
 	uint32_t crc;
 
diff --git a/drivers/mtd/ubi/gluebi.c b/drivers/mtd/ubi/gluebi.c
index 41ff74c60e14..d397219238d3 100644
--- a/drivers/mtd/ubi/gluebi.c
+++ b/drivers/mtd/ubi/gluebi.c
@@ -129,8 +129,7 @@ static int gluebi_read(struct mtd_info *mtd, loff_t from, size_t len,
 		if (to_read > total_read)
 			to_read = total_read;
 
-		err = ubi_eba_read_leb(ubi, vol->vol_id, lnum, buf, offs,
-				       to_read, 0);
+		err = ubi_eba_read_leb(ubi, vol, lnum, buf, offs, to_read, 0);
 		if (err)
 			break;
 
@@ -187,8 +186,8 @@ static int gluebi_write(struct mtd_info *mtd, loff_t to, size_t len,
 		if (to_write > total_written)
 			to_write = total_written;
 
-		err = ubi_eba_write_leb(ubi, vol->vol_id, lnum, buf, offs,
-					to_write, UBI_UNKNOWN);
+		err = ubi_eba_write_leb(ubi, vol, lnum, buf, offs, to_write,
+					UBI_UNKNOWN);
 		if (err)
 			break;
 
@@ -237,7 +236,7 @@ static int gluebi_erase(struct mtd_info *mtd, struct erase_info *instr)
 		return -EROFS;
 
 	for (i = 0; i < count; i++) {
-		err = ubi_eba_unmap_leb(ubi, vol->vol_id, lnum + i);
+		err = ubi_eba_unmap_leb(ubi, vol, lnum + i);
 		if (err)
 			goto out_err;
 	}
diff --git a/drivers/mtd/ubi/kapi.c b/drivers/mtd/ubi/kapi.c
index 3bf2c951c2e5..c2fafe6fb2da 100644
--- a/drivers/mtd/ubi/kapi.c
+++ b/drivers/mtd/ubi/kapi.c
@@ -332,7 +332,7 @@ int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
 	if (len == 0)
 		return 0;
 
-	err = ubi_eba_read_leb(ubi, vol_id, lnum, buf, offset, len, check);
+	err = ubi_eba_read_leb(ubi, vol, lnum, buf, offset, len, check);
 	if (err && err == -EBADMSG && vol->vol_type == UBI_STATIC_VOLUME) {
 		ubi_warn("mark volume %d as corrupted", vol_id);
 		vol->corrupted = 1;
@@ -399,7 +399,7 @@ int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
 	if (len == 0)
 		return 0;
 
-	return ubi_eba_write_leb(ubi, vol_id, lnum, buf, offset, len, dtype);
+	return ubi_eba_write_leb(ubi, vol, lnum, buf, offset, len, dtype);
 }
 EXPORT_SYMBOL_GPL(ubi_leb_write);
 
@@ -448,7 +448,7 @@ int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
 	if (len == 0)
 		return 0;
 
-	return ubi_eba_atomic_leb_change(ubi, vol_id, lnum, buf, len, dtype);
+	return ubi_eba_atomic_leb_change(ubi, vol, lnum, buf, len, dtype);
 }
 EXPORT_SYMBOL_GPL(ubi_leb_change);
 
@@ -481,7 +481,7 @@ int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum)
 	if (vol->upd_marker)
 		return -EBADF;
 
-	err = ubi_eba_unmap_leb(ubi, vol_id, lnum);
+	err = ubi_eba_unmap_leb(ubi, vol, lnum);
 	if (err)
 		return err;
 
@@ -542,7 +542,7 @@ int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum)
 	if (vol->upd_marker)
 		return -EBADF;
 
-	return ubi_eba_unmap_leb(ubi, vol_id, lnum);
+	return ubi_eba_unmap_leb(ubi, vol, lnum);
 }
 EXPORT_SYMBOL_GPL(ubi_leb_unmap);
 
@@ -587,7 +587,7 @@ int ubi_leb_map(struct ubi_volume_desc *desc, int lnum, int dtype)
 	if (vol->eba_tbl[lnum] >= 0)
 		return -EBADMSG;
 
-	return ubi_eba_write_leb(ubi, vol_id, lnum, NULL, 0, 0, dtype);
+	return ubi_eba_write_leb(ubi, vol, lnum, NULL, 0, 0, dtype);
 }
 EXPORT_SYMBOL_GPL(ubi_leb_map);
 
diff --git a/drivers/mtd/ubi/misc.c b/drivers/mtd/ubi/misc.c
index 9e2338c8e2cf..93e052812012 100644
--- a/drivers/mtd/ubi/misc.c
+++ b/drivers/mtd/ubi/misc.c
@@ -79,7 +79,7 @@ int ubi_check_volume(struct ubi_device *ubi, int vol_id)
 		else
 			size = vol->usable_leb_size;
 
-		err = ubi_eba_read_leb(ubi, vol_id, i, buf, 0, size, 1);
+		err = ubi_eba_read_leb(ubi, vol, i, buf, 0, size, 1);
 		if (err) {
 			if (err == -EBADMSG)
 				err = 1;
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index 23875bf6aa3b..0a3a803dd22f 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -410,8 +410,8 @@ int ubi_read_volume_table(struct ubi_device *ubi, struct ubi_scan_info *si);
 int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req);
 int ubi_remove_volume(struct ubi_volume_desc *desc);
 int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs);
-int ubi_add_volume(struct ubi_device *ubi, int vol_id);
-void ubi_free_volume(struct ubi_device *ubi, int vol_id);
+int ubi_add_volume(struct ubi_device *ubi, struct ubi_volume *vol);
+void ubi_free_volume(struct ubi_device *ubi, struct ubi_volume *vol);
 
 /* upd.c */
 int ubi_start_update(struct ubi_device *ubi, int vol_id, long long bytes);
@@ -435,16 +435,17 @@ void ubi_gluebi_updated(struct ubi_volume *vol);
 #endif
 
 /* eba.c */
-int ubi_eba_unmap_leb(struct ubi_device *ubi, int vol_id, int lnum);
-int ubi_eba_read_leb(struct ubi_device *ubi, int vol_id, int lnum, void *buf,
-		     int offset, int len, int check);
-int ubi_eba_write_leb(struct ubi_device *ubi, int vol_id, int lnum,
+int ubi_eba_unmap_leb(struct ubi_device *ubi, struct ubi_volume *vol,
+		      int lnum);
+int ubi_eba_read_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
+		     void *buf, int offset, int len, int check);
+int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
 		      const void *buf, int offset, int len, int dtype);
-int ubi_eba_write_leb_st(struct ubi_device *ubi, int vol_id, int lnum,
-			 const void *buf, int len, int dtype,
+int ubi_eba_write_leb_st(struct ubi_device *ubi, struct ubi_volume *vol,
+			 int lnum, const void *buf, int len, int dtype,
 			 int used_ebs);
-int ubi_eba_atomic_leb_change(struct ubi_device *ubi, int vol_id, int lnum,
-			      const void *buf, int len, int dtype);
+int ubi_eba_atomic_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
+			      int lnum, const void *buf, int len, int dtype);
 int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
 		     struct ubi_vid_hdr *vid_hdr);
 int ubi_eba_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si);
diff --git a/drivers/mtd/ubi/upd.c b/drivers/mtd/ubi/upd.c
index 0efc586a8328..a95dcaa4a0c2 100644
--- a/drivers/mtd/ubi/upd.c
+++ b/drivers/mtd/ubi/upd.c
@@ -136,7 +136,7 @@ int ubi_start_update(struct ubi_device *ubi, int vol_id, long long bytes)
 
 	/* Before updating - wipe out the volume */
 	for (i = 0; i < vol->reserved_pebs; i++) {
-		err = ubi_eba_unmap_leb(ubi, vol_id, i);
+		err = ubi_eba_unmap_leb(ubi, vol, i);
 		if (err)
 			return err;
 	}
@@ -209,8 +209,7 @@ static int write_leb(struct ubi_device *ubi, int vol_id, int lnum, void *buf,
 		if (len != l)
 			dbg_msg("skip last %d bytes (0xFF)", len - l);
 
-		err = ubi_eba_write_leb(ubi, vol_id, lnum, buf, 0, l,
-					UBI_UNKNOWN);
+		err = ubi_eba_write_leb(ubi, vol, lnum, buf, 0, l, UBI_UNKNOWN);
 	} else {
 		/*
 		 * When writing static volume, and this is the last logical
@@ -222,7 +221,7 @@ static int write_leb(struct ubi_device *ubi, int vol_id, int lnum, void *buf,
 		 * contain zeros, not random trash.
 		 */
 		memset(buf + len, 0, vol->usable_leb_size - len);
-		err = ubi_eba_write_leb_st(ubi, vol_id, lnum, buf, len,
+		err = ubi_eba_write_leb_st(ubi, vol, lnum, buf, len,
 					   UBI_UNKNOWN, used_ebs);
 	}
 
diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c
index 787ce9ec17ae..d2d12deead5c 100644
--- a/drivers/mtd/ubi/vmt.c
+++ b/drivers/mtd/ubi/vmt.c
@@ -417,7 +417,7 @@ int ubi_remove_volume(struct ubi_volume_desc *desc)
 		return err;
 
 	for (i = 0; i < vol->reserved_pebs; i++) {
-		err = ubi_eba_unmap_leb(ubi, vol_id, i);
+		err = ubi_eba_unmap_leb(ubi, vol, i);
 		if (err)
 			return err;
 	}
@@ -524,7 +524,7 @@ int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs)
 
 	if (pebs < 0) {
 		for (i = 0; i < -pebs; i++) {
-			err = ubi_eba_unmap_leb(ubi, vol_id, reserved_pebs + i);
+			err = ubi_eba_unmap_leb(ubi, vol, reserved_pebs + i);
 			if (err)
 				goto out_acc;
 		}
@@ -573,17 +573,16 @@ int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs)
 /**
  * ubi_add_volume - add volume.
  * @ubi: UBI device description object
- * @vol_id: volume ID
+ * @vol: volume description object
  *
  * This function adds an existin volume and initializes all its data
  * structures. Returnes zero in case of success and a negative error code in
  * case of failure.
  */
-int ubi_add_volume(struct ubi_device *ubi, int vol_id)
+int ubi_add_volume(struct ubi_device *ubi, struct ubi_volume *vol)
 {
-	int err;
+	int err, vol_id = vol->vol_id;
 	dev_t dev;
-	struct ubi_volume *vol = ubi->volumes[vol_id];
 
 	dbg_msg("add volume %d", vol_id);
 	ubi_dbg_dump_vol_info(vol);
@@ -634,22 +633,21 @@ int ubi_add_volume(struct ubi_device *ubi, int vol_id)
 /**
  * ubi_free_volume - free volume.
  * @ubi: UBI device description object
- * @vol_id: volume ID
+ * @vol: volume description object
  *
- * This function frees all resources for volume @vol_id but does not remove it.
+ * This function frees all resources for volume @vol but does not remove it.
  * Used only when the UBI device is detached.
  */
-void ubi_free_volume(struct ubi_device *ubi, int vol_id)
+void ubi_free_volume(struct ubi_device *ubi, struct ubi_volume *vol)
 {
 	int err;
-	struct ubi_volume *vol = ubi->volumes[vol_id];
 
-	dbg_msg("free volume %d", vol_id);
+	dbg_msg("free volume %d", vol->vol_id);
 	ubi_assert(vol);
 
 	vol->removed = 1;
 	err = ubi_destroy_gluebi(vol);
-	ubi->volumes[vol_id] = NULL;
+	ubi->volumes[vol->vol_id] = NULL;
 	cdev_del(&vol->cdev);
 	volume_sysfs_close(vol);
 }
diff --git a/drivers/mtd/ubi/vtbl.c b/drivers/mtd/ubi/vtbl.c
index 25b3bd61c7ec..3349c281bf9e 100644
--- a/drivers/mtd/ubi/vtbl.c
+++ b/drivers/mtd/ubi/vtbl.c
@@ -86,8 +86,10 @@ int ubi_change_vtbl_record(struct ubi_device *ubi, int idx,
 {
 	int i, err;
 	uint32_t crc;
+	struct ubi_volume *layout_vol;
 
 	ubi_assert(idx >= 0 && idx < ubi->vtbl_slots);
+	layout_vol = ubi->volumes[vol_id2idx(UBI_LAYOUT_VOL_ID)];
 
 	if (!vtbl_rec)
 		vtbl_rec = &empty_vtbl_record;
@@ -99,12 +101,12 @@ int ubi_change_vtbl_record(struct ubi_device *ubi, int idx,
 	mutex_lock(&ubi->vtbl_mutex);
 	memcpy(&ubi->vtbl[idx], vtbl_rec, sizeof(struct ubi_vtbl_record));
 	for (i = 0; i < UBI_LAYOUT_VOLUME_EBS; i++) {
-		err = ubi_eba_unmap_leb(ubi, UBI_LAYOUT_VOL_ID, i);
+		err = ubi_eba_unmap_leb(ubi, layout_vol, i);
 		if (err) {
 			mutex_unlock(&ubi->vtbl_mutex);
 			return err;
 		}
-		err = ubi_eba_write_leb(ubi, UBI_LAYOUT_VOL_ID, i, ubi->vtbl, 0,
+		err = ubi_eba_write_leb(ubi, layout_vol, i, ubi->vtbl, 0,
 					ubi->vtbl_size, UBI_LONGTERM);
 		if (err) {
 			mutex_unlock(&ubi->vtbl_mutex);