Commit 34b89df9 authored by Sebastian Siewior's avatar Sebastian Siewior Committed by Richard Weinberger
Browse files

mtd: ubi: wl: avoid erasing a PEB which is empty 



wear_leveling_worker() currently unconditionally puts a PEB on erase in
the error case even it just been taken from the free_list and never
used.
In case the PEB was never used it can be put back on the free list
saving a precious erase cycle.

v1…v2:
	- to_leb_clean -> dst_leb_clean
	- use the nested option for ensure_wear_leveling()
	- do_sync_erase() can't go -ENOMEM so we can just go into
	  RO-mode now.

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarRichard Weinberger <richard@nod.at>
parent 16830985

drivers/mtd/ubi/wl.c

+18 −3
Original line number Diff line number Diff line
@@ -628,6 +628,7 @@ static int do_sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e, 
	return __erase_worker(ubi, &wl_wrk);

}



static int ensure_wear_leveling(struct ubi_device *ubi, int nested);

/**

 * wear_leveling_worker - wear-leveling worker function.

 * @ubi: UBI device description object
@@ -649,6 +650,7 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk, 
#endif

	struct ubi_wl_entry *e1, *e2;

	struct ubi_vid_hdr *vid_hdr;

	int dst_leb_clean = 0;



	kfree(wrk);

	if (shutdown)
@@ -753,6 +755,7 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk, 


	err = ubi_io_read_vid_hdr(ubi, e1->pnum, vid_hdr, 0);

	if (err && err != UBI_IO_BITFLIPS) {

		dst_leb_clean = 1;

		if (err == UBI_IO_FF) {

			/*

			 * We are trying to move PEB without a VID header. UBI
@@ -798,10 +801,12 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk, 
			 * protection queue.

			 */

			protect = 1;

			dst_leb_clean = 1;

			goto out_not_moved;

		}

		if (err == MOVE_RETRY) {

			scrubbing = 1;

			dst_leb_clean = 1;

			goto out_not_moved;

		}

		if (err == MOVE_TARGET_BITFLIPS || err == MOVE_TARGET_WR_ERR ||
@@ -827,6 +832,7 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk, 
					ubi->erroneous_peb_count);

				goto out_error;

			}

			dst_leb_clean = 1;

			erroneous = 1;

			goto out_not_moved;

		}
@@ -897,15 +903,24 @@ out_not_moved: 
		wl_tree_add(e1, &ubi->scrub);

	else

		wl_tree_add(e1, &ubi->used);

	if (dst_leb_clean) {

		wl_tree_add(e2, &ubi->free);

		ubi->free_count++;

	}



	ubi_assert(!ubi->move_to_put);

	ubi->move_from = ubi->move_to = NULL;

	ubi->wl_scheduled = 0;

	spin_unlock(&ubi->wl_lock);



	ubi_free_vid_hdr(ubi, vid_hdr);

	if (dst_leb_clean) {

		ensure_wear_leveling(ubi, 1);

	} else {

		err = do_sync_erase(ubi, e2, vol_id, lnum, torture);

		if (err)

			goto out_ro;

	}



	mutex_unlock(&ubi->move_mutex);

	return 0;

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