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Commit b5da7525 authored by Sebastian Siewior's avatar Sebastian Siewior Committed by Nikhilesh Reddy
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.

CRs-Fixed: 975289
Change-Id: I9955366673af13e6cfd3da3523dba4857b2b4ea2
Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarRichard Weinberger <richard@nod.at>
Git-commit: 34b89df90374b631692132640c6b3dbef52f808d
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: default avatarNikhilesh Reddy <reddyn@codeaurora.org>
parent 84d51d45

drivers/mtd/ubi/wl.c

+18 −3
Original line number Diff line number Diff line
@@ -647,6 +647,7 @@ 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
@@ -668,6 +669,7 @@ 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)
@@ -772,6 +774,7 @@ 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
@@ -817,10 +820,12 @@ 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 ||
@@ -846,6 +851,7 @@ 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;

		}
@@ -926,15 +932,24 @@ 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;