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

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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 <bigeasy@linutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
This commit is contained in:
Sebastian Siewior 2015-11-26 21:23:50 +01:00 committed by Richard Weinberger
parent 168309855a
commit 34b89df903
1 changed files with 18 additions and 3 deletions
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21
drivers/mtd/ubi/wl.c
View file

@ -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 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
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;