diff options
Diffstat (limited to 'drivers/mtd/ubi/wl.c')
| -rw-r--r-- | drivers/mtd/ubi/wl.c | 174 |
1 files changed, 167 insertions, 7 deletions
diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c index 6f2ac865ff05..2709dc02fc24 100644 --- a/drivers/mtd/ubi/wl.c +++ b/drivers/mtd/ubi/wl.c @@ -278,6 +278,27 @@ static int in_wl_tree(struct ubi_wl_entry *e, struct rb_root *root) } /** + * in_pq - check if a wear-leveling entry is present in the protection queue. + * @ubi: UBI device description object + * @e: the wear-leveling entry to check + * + * This function returns non-zero if @e is in the protection queue and zero + * if it is not. + */ +static inline int in_pq(const struct ubi_device *ubi, struct ubi_wl_entry *e) +{ + struct ubi_wl_entry *p; + int i; + + for (i = 0; i < UBI_PROT_QUEUE_LEN; ++i) + list_for_each_entry(p, &ubi->pq[i], u.list) + if (p == e) + return 1; + + return 0; +} + +/** * prot_queue_add - add physical eraseblock to the protection queue. * @ubi: UBI device description object * @e: the physical eraseblock to add @@ -1419,6 +1440,150 @@ int ubi_wl_flush(struct ubi_device *ubi, int vol_id, int lnum) return err; } +static bool scrub_possible(struct ubi_device *ubi, struct ubi_wl_entry *e) +{ + if (in_wl_tree(e, &ubi->scrub)) + return false; + else if (in_wl_tree(e, &ubi->erroneous)) + return false; + else if (ubi->move_from == e) + return false; + else if (ubi->move_to == e) + return false; + + return true; +} + +/** + * ubi_bitflip_check - Check an eraseblock for bitflips and scrub it if needed. + * @ubi: UBI device description object + * @pnum: the physical eraseblock to schedule + * @force: dont't read the block, assume bitflips happened and take action. + * + * This function reads the given eraseblock and checks if bitflips occured. + * In case of bitflips, the eraseblock is scheduled for scrubbing. + * If scrubbing is forced with @force, the eraseblock is not read, + * but scheduled for scrubbing right away. + * + * Returns: + * %EINVAL, PEB is out of range + * %ENOENT, PEB is no longer used by UBI + * %EBUSY, PEB cannot be checked now or a check is currently running on it + * %EAGAIN, bit flips happened but scrubbing is currently not possible + * %EUCLEAN, bit flips happened and PEB is scheduled for scrubbing + * %0, no bit flips detected + */ +int ubi_bitflip_check(struct ubi_device *ubi, int pnum, int force) +{ + int err; + struct ubi_wl_entry *e; + + if (pnum < 0 || pnum >= ubi->peb_count) { + err = -EINVAL; + goto out; + } + + /* + * Pause all parallel work, otherwise it can happen that the + * erase worker frees a wl entry under us. + */ + down_write(&ubi->work_sem); + + /* + * Make sure that the wl entry does not change state while + * inspecting it. + */ + spin_lock(&ubi->wl_lock); + e = ubi->lookuptbl[pnum]; + if (!e) { + spin_unlock(&ubi->wl_lock); + err = -ENOENT; + goto out_resume; + } + + /* + * Does it make sense to check this PEB? + */ + if (!scrub_possible(ubi, e)) { + spin_unlock(&ubi->wl_lock); + err = -EBUSY; + goto out_resume; + } + spin_unlock(&ubi->wl_lock); + + if (!force) { + mutex_lock(&ubi->buf_mutex); + err = ubi_io_read(ubi, ubi->peb_buf, pnum, 0, ubi->peb_size); + mutex_unlock(&ubi->buf_mutex); + } + + if (force || err == UBI_IO_BITFLIPS) { + /* + * Okay, bit flip happened, let's figure out what we can do. + */ + spin_lock(&ubi->wl_lock); + + /* + * Recheck. We released wl_lock, UBI might have killed the + * wl entry under us. + */ + e = ubi->lookuptbl[pnum]; + if (!e) { + spin_unlock(&ubi->wl_lock); + err = -ENOENT; + goto out_resume; + } + + /* + * Need to re-check state + */ + if (!scrub_possible(ubi, e)) { + spin_unlock(&ubi->wl_lock); + err = -EBUSY; + goto out_resume; + } + + if (in_pq(ubi, e)) { + prot_queue_del(ubi, e->pnum); + wl_tree_add(e, &ubi->scrub); + spin_unlock(&ubi->wl_lock); + + err = ensure_wear_leveling(ubi, 1); + } else if (in_wl_tree(e, &ubi->used)) { + rb_erase(&e->u.rb, &ubi->used); + wl_tree_add(e, &ubi->scrub); + spin_unlock(&ubi->wl_lock); + + err = ensure_wear_leveling(ubi, 1); + } else if (in_wl_tree(e, &ubi->free)) { + rb_erase(&e->u.rb, &ubi->free); + ubi->free_count--; + spin_unlock(&ubi->wl_lock); + + /* + * This PEB is empty we can schedule it for + * erasure right away. No wear leveling needed. + */ + err = schedule_erase(ubi, e, UBI_UNKNOWN, UBI_UNKNOWN, + force ? 0 : 1, true); + } else { + spin_unlock(&ubi->wl_lock); + err = -EAGAIN; + } + + if (!err && !force) + err = -EUCLEAN; + } else { + err = 0; + } + +out_resume: + up_write(&ubi->work_sem); +out: + + return err; +} + /** * tree_destroy - destroy an RB-tree. * @ubi: UBI device description object @@ -1848,16 +2013,11 @@ static int self_check_in_wl_tree(const struct ubi_device *ubi, static int self_check_in_pq(const struct ubi_device *ubi, struct ubi_wl_entry *e) { - struct ubi_wl_entry *p; - int i; - if (!ubi_dbg_chk_gen(ubi)) return 0; - for (i = 0; i < UBI_PROT_QUEUE_LEN; ++i) - list_for_each_entry(p, &ubi->pq[i], u.list) - if (p == e) - return 0; + if (in_pq(ubi, e)) + return 0; ubi_err(ubi, "self-check failed for PEB %d, EC %d, Protect queue", e->pnum, e->ec); |