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Commit 7b6c32da authored by Xiaochuan-Xu's avatar Xiaochuan-Xu Committed by Artem Bityutskiy
Browse files

UBI: simplify PEB protection code 



UBI has 2 RB-trees to implement PEB protection, which is too
much for simply prevent PEB from being moved for some time.
This patch implements this using lists. The benefits:

1. No need to allocate protection entry on each PEB get.
2. No need to maintain balanced trees and walk them.

Signed-off-by: default avatarXiaochuan-Xu <xiaochuan-xu@cqu.edu.cn>
Signed-off-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
parent 23553b2c

drivers/mtd/ubi/ubi.h

+22 −17
Original line number Diff line number Diff line
@@ -73,6 +73,13 @@ 
 */

#define UBI_IO_RETRIES 3



/*

 * Length of the protection queue. The length is effectively equivalent to the

 * number of (global) erase cycles PEBs are protected from the wear-leveling

 * worker.

 */

#define UBI_PROT_QUEUE_LEN 10



/*

 * Error codes returned by the I/O sub-system.

 *
@@ -96,6 +103,7 @@ enum { 
/**

 * struct ubi_wl_entry - wear-leveling entry.

 * @u.rb: link in the corresponding (free/used) RB-tree

 * @u.list: link in the protection queue

 * @ec: erase counter

 * @pnum: physical eraseblock number

 *
@@ -106,6 +114,7 @@ enum { 
struct ubi_wl_entry {

	union {

		struct rb_node rb;

		struct list_head list;

	} u;

	int ec;

	int pnum;
@@ -290,7 +299,7 @@ struct ubi_wl_entry; 
 * @beb_rsvd_level: normal level of PEBs reserved for bad PEB handling

 *

 * @autoresize_vol_id: ID of the volume which has to be auto-resized at the end

 *                     of UBI ititializetion

 *                     of UBI initialization

 * @vtbl_slots: how many slots are available in the volume table

 * @vtbl_size: size of the volume table in bytes

 * @vtbl: in-RAM volume table copy
@@ -308,18 +317,17 @@ struct ubi_wl_entry; 
 * @used: RB-tree of used physical eraseblocks

 * @free: RB-tree of free physical eraseblocks

 * @scrub: RB-tree of physical eraseblocks which need scrubbing

 * @prot: protection trees

 * @prot.pnum: protection tree indexed by physical eraseblock numbers

 * @prot.aec: protection tree indexed by absolute erase counter value

 * @wl_lock: protects the @used, @free, @prot, @lookuptbl, @abs_ec, @move_from,

 *           @move_to, @move_to_put @erase_pending, @wl_scheduled, and @works

 * @pq: protection queue (contain physical eraseblocks which are temporarily

 *      protected from the wear-leveling worker)

 * @pq_head: protection queue head

 * @wl_lock: protects the @used, @free, @pq, @pq_head, @lookuptbl, @move_from,

 * 	     @move_to, @move_to_put @erase_pending, @wl_scheduled and @works

 * 	     fields

 * @move_mutex: serializes eraseblock moves

 * @work_sem: sycnhronizes the WL worker with use tasks

 * @work_sem: synchronizes the WL worker with use tasks

 * @wl_scheduled: non-zero if the wear-leveling was scheduled

 * @lookuptbl: a table to quickly find a &struct ubi_wl_entry object for any

 *             physical eraseblock

 * @abs_ec: absolute erase counter

 * @move_from: physical eraseblock from where the data is being moved

 * @move_to: physical eraseblock where the data is being moved to

 * @move_to_put: if the "to" PEB was put
@@ -353,11 +361,11 @@ struct ubi_wl_entry; 
 *

 * @peb_buf1: a buffer of PEB size used for different purposes

 * @peb_buf2: another buffer of PEB size used for different purposes

 * @buf_mutex: proptects @peb_buf1 and @peb_buf2

 * @buf_mutex: protects @peb_buf1 and @peb_buf2

 * @ckvol_mutex: serializes static volume checking when opening

 * @mult_mutex: serializes operations on multiple volumes, like re-nameing

 * @mult_mutex: serializes operations on multiple volumes, like re-naming

 * @dbg_peb_buf: buffer of PEB size used for debugging

 * @dbg_buf_mutex: proptects @dbg_peb_buf

 * @dbg_buf_mutex: protects @dbg_peb_buf

 */

struct ubi_device {

	struct cdev cdev;
@@ -394,16 +402,13 @@ struct ubi_device { 
	struct rb_root used;

	struct rb_root free;

	struct rb_root scrub;

	struct {

		struct rb_root pnum;

		struct rb_root aec;

	} prot;

	struct list_head pq[UBI_PROT_QUEUE_LEN];

	int pq_head;

	spinlock_t wl_lock;

	struct mutex move_mutex;

	struct rw_semaphore work_sem;

	int wl_scheduled;

	struct ubi_wl_entry **lookuptbl;

	unsigned long long abs_ec;

	struct ubi_wl_entry *move_from;

	struct ubi_wl_entry *move_to;

	int move_to_put;

drivers/mtd/ubi/wl.c

+140 −224

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