evie/android_kernel_oneplus_msm8998
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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.

CRs-Fixed: 975289
Change-Id: I9955366673af13e6cfd3da3523dba4857b2b4ea2
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
Git-commit: 34b89df90374b631692132640c6b3dbef52f808d
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Nikhilesh Reddy <reddyn@codeaurora.org>
This commit is contained in:
Sebastian Siewior 2015-11-26 21:23:50 +01:00 • committed by David Keitel
parent 44cd578eeb
commit 091bf2e3ba
1 changed files with 18 additions and 3 deletions
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21
drivers/mtd/ubi/wl.c
View file

@ -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);
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;