From 34b89df90374b631692132640c6b3dbef52f808d Mon Sep 17 00:00:00 2001 From: Sebastian Siewior Date: Thu, 26 Nov 2015 21:23:50 +0100 Subject: [PATCH] mtd: ubi: wl: avoid erasing a PEB which is empty MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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: Sebastian Andrzej Siewior Signed-off-by: Richard Weinberger --- drivers/mtd/ubi/wl.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c index 56065632a5b8..17ec948ac40e 100644 --- a/drivers/mtd/ubi/wl.c +++ b/drivers/mtd/ubi/wl.c @@ -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); - err = do_sync_erase(ubi, e2, vol_id, lnum, torture); - if (err) - goto out_ro; + 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; -- 2.20.1