From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- drivers/mtd/ubi/fastmap-wl.c | 362 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 362 insertions(+) create mode 100644 drivers/mtd/ubi/fastmap-wl.c (limited to 'drivers/mtd/ubi/fastmap-wl.c') diff --git a/drivers/mtd/ubi/fastmap-wl.c b/drivers/mtd/ubi/fastmap-wl.c new file mode 100644 index 000000000..b2a665398 --- /dev/null +++ b/drivers/mtd/ubi/fastmap-wl.c @@ -0,0 +1,362 @@ +/* + * Copyright (c) 2012 Linutronix GmbH + * Copyright (c) 2014 sigma star gmbh + * Author: Richard Weinberger + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See + * the GNU General Public License for more details. + * + */ + +/** + * update_fastmap_work_fn - calls ubi_update_fastmap from a work queue + * @wrk: the work description object + */ +static void update_fastmap_work_fn(struct work_struct *wrk) +{ + struct ubi_device *ubi = container_of(wrk, struct ubi_device, fm_work); + + ubi_update_fastmap(ubi); + spin_lock(&ubi->wl_lock); + ubi->fm_work_scheduled = 0; + spin_unlock(&ubi->wl_lock); +} + +/** + * find_anchor_wl_entry - find wear-leveling entry to used as anchor PEB. + * @root: the RB-tree where to look for + */ +static struct ubi_wl_entry *find_anchor_wl_entry(struct rb_root *root) +{ + struct rb_node *p; + struct ubi_wl_entry *e, *victim = NULL; + int max_ec = UBI_MAX_ERASECOUNTER; + + ubi_rb_for_each_entry(p, e, root, u.rb) { + if (e->pnum < UBI_FM_MAX_START && e->ec < max_ec) { + victim = e; + max_ec = e->ec; + } + } + + return victim; +} + +/** + * return_unused_pool_pebs - returns unused PEB to the free tree. + * @ubi: UBI device description object + * @pool: fastmap pool description object + */ +static void return_unused_pool_pebs(struct ubi_device *ubi, + struct ubi_fm_pool *pool) +{ + int i; + struct ubi_wl_entry *e; + + for (i = pool->used; i < pool->size; i++) { + e = ubi->lookuptbl[pool->pebs[i]]; + wl_tree_add(e, &ubi->free); + ubi->free_count++; + } +} + +static int anchor_pebs_avalible(struct rb_root *root) +{ + struct rb_node *p; + struct ubi_wl_entry *e; + + ubi_rb_for_each_entry(p, e, root, u.rb) + if (e->pnum < UBI_FM_MAX_START) + return 1; + + return 0; +} + +/** + * ubi_wl_get_fm_peb - find a physical erase block with a given maximal number. + * @ubi: UBI device description object + * @anchor: This PEB will be used as anchor PEB by fastmap + * + * The function returns a physical erase block with a given maximal number + * and removes it from the wl subsystem. + * Must be called with wl_lock held! + */ +struct ubi_wl_entry *ubi_wl_get_fm_peb(struct ubi_device *ubi, int anchor) +{ + struct ubi_wl_entry *e = NULL; + + if (!ubi->free.rb_node || (ubi->free_count - ubi->beb_rsvd_pebs < 1)) + goto out; + + if (anchor) + e = find_anchor_wl_entry(&ubi->free); + else + e = find_mean_wl_entry(ubi, &ubi->free); + + if (!e) + goto out; + + self_check_in_wl_tree(ubi, e, &ubi->free); + + /* remove it from the free list, + * the wl subsystem does no longer know this erase block */ + rb_erase(&e->u.rb, &ubi->free); + ubi->free_count--; +out: + return e; +} + +/** + * ubi_refill_pools - refills all fastmap PEB pools. + * @ubi: UBI device description object + */ +void ubi_refill_pools(struct ubi_device *ubi) +{ + struct ubi_fm_pool *wl_pool = &ubi->fm_wl_pool; + struct ubi_fm_pool *pool = &ubi->fm_pool; + struct ubi_wl_entry *e; + int enough; + + spin_lock(&ubi->wl_lock); + + return_unused_pool_pebs(ubi, wl_pool); + return_unused_pool_pebs(ubi, pool); + + wl_pool->size = 0; + pool->size = 0; + + for (;;) { + enough = 0; + if (pool->size < pool->max_size) { + if (!ubi->free.rb_node) + break; + + e = wl_get_wle(ubi); + if (!e) + break; + + pool->pebs[pool->size] = e->pnum; + pool->size++; + } else + enough++; + + if (wl_pool->size < wl_pool->max_size) { + if (!ubi->free.rb_node || + (ubi->free_count - ubi->beb_rsvd_pebs < 5)) + break; + + e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF); + self_check_in_wl_tree(ubi, e, &ubi->free); + rb_erase(&e->u.rb, &ubi->free); + ubi->free_count--; + + wl_pool->pebs[wl_pool->size] = e->pnum; + wl_pool->size++; + } else + enough++; + + if (enough == 2) + break; + } + + wl_pool->used = 0; + pool->used = 0; + + spin_unlock(&ubi->wl_lock); +} + +/** + * ubi_wl_get_peb - get a physical eraseblock. + * @ubi: UBI device description object + * + * This function returns a physical eraseblock in case of success and a + * negative error code in case of failure. + * Returns with ubi->fm_eba_sem held in read mode! + */ +int ubi_wl_get_peb(struct ubi_device *ubi) +{ + int ret, retried = 0; + struct ubi_fm_pool *pool = &ubi->fm_pool; + struct ubi_fm_pool *wl_pool = &ubi->fm_wl_pool; + +again: + down_read(&ubi->fm_eba_sem); + spin_lock(&ubi->wl_lock); + + /* We check here also for the WL pool because at this point we can + * refill the WL pool synchronous. */ + if (pool->used == pool->size || wl_pool->used == wl_pool->size) { + spin_unlock(&ubi->wl_lock); + up_read(&ubi->fm_eba_sem); + ret = ubi_update_fastmap(ubi); + if (ret) { + ubi_msg(ubi, "Unable to write a new fastmap: %i", ret); + down_read(&ubi->fm_eba_sem); + return -ENOSPC; + } + down_read(&ubi->fm_eba_sem); + spin_lock(&ubi->wl_lock); + } + + if (pool->used == pool->size) { + spin_unlock(&ubi->wl_lock); + if (retried) { + ubi_err(ubi, "Unable to get a free PEB from user WL pool"); + ret = -ENOSPC; + goto out; + } + retried = 1; + up_read(&ubi->fm_eba_sem); + goto again; + } + + ubi_assert(pool->used < pool->size); + ret = pool->pebs[pool->used++]; + prot_queue_add(ubi, ubi->lookuptbl[ret]); + spin_unlock(&ubi->wl_lock); +out: + return ret; +} + +/* get_peb_for_wl - returns a PEB to be used internally by the WL sub-system. + * + * @ubi: UBI device description object + */ +static struct ubi_wl_entry *get_peb_for_wl(struct ubi_device *ubi) +{ + struct ubi_fm_pool *pool = &ubi->fm_wl_pool; + int pnum; + + if (pool->used == pool->size) { + /* We cannot update the fastmap here because this + * function is called in atomic context. + * Let's fail here and refill/update it as soon as possible. */ + if (!ubi->fm_work_scheduled) { + ubi->fm_work_scheduled = 1; + schedule_work(&ubi->fm_work); + } + return NULL; + } + + pnum = pool->pebs[pool->used++]; + return ubi->lookuptbl[pnum]; +} + +/** + * ubi_ensure_anchor_pebs - schedule wear-leveling to produce an anchor PEB. + * @ubi: UBI device description object + */ +int ubi_ensure_anchor_pebs(struct ubi_device *ubi) +{ + struct ubi_work *wrk; + + spin_lock(&ubi->wl_lock); + if (ubi->wl_scheduled) { + spin_unlock(&ubi->wl_lock); + return 0; + } + ubi->wl_scheduled = 1; + spin_unlock(&ubi->wl_lock); + + wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS); + if (!wrk) { + spin_lock(&ubi->wl_lock); + ubi->wl_scheduled = 0; + spin_unlock(&ubi->wl_lock); + return -ENOMEM; + } + + wrk->anchor = 1; + wrk->func = &wear_leveling_worker; + schedule_ubi_work(ubi, wrk); + return 0; +} + +/** + * ubi_wl_put_fm_peb - returns a PEB used in a fastmap to the wear-leveling + * sub-system. + * see: ubi_wl_put_peb() + * + * @ubi: UBI device description object + * @fm_e: physical eraseblock to return + * @lnum: the last used logical eraseblock number for the PEB + * @torture: if this physical eraseblock has to be tortured + */ +int ubi_wl_put_fm_peb(struct ubi_device *ubi, struct ubi_wl_entry *fm_e, + int lnum, int torture) +{ + struct ubi_wl_entry *e; + int vol_id, pnum = fm_e->pnum; + + dbg_wl("PEB %d", pnum); + + ubi_assert(pnum >= 0); + ubi_assert(pnum < ubi->peb_count); + + spin_lock(&ubi->wl_lock); + e = ubi->lookuptbl[pnum]; + + /* This can happen if we recovered from a fastmap the very + * first time and writing now a new one. In this case the wl system + * has never seen any PEB used by the original fastmap. + */ + if (!e) { + e = fm_e; + ubi_assert(e->ec >= 0); + ubi->lookuptbl[pnum] = e; + } + + spin_unlock(&ubi->wl_lock); + + vol_id = lnum ? UBI_FM_DATA_VOLUME_ID : UBI_FM_SB_VOLUME_ID; + return schedule_erase(ubi, e, vol_id, lnum, torture); +} + +/** + * ubi_is_erase_work - checks whether a work is erase work. + * @wrk: The work object to be checked + */ +int ubi_is_erase_work(struct ubi_work *wrk) +{ + return wrk->func == erase_worker; +} + +static void ubi_fastmap_close(struct ubi_device *ubi) +{ + int i; + + flush_work(&ubi->fm_work); + return_unused_pool_pebs(ubi, &ubi->fm_pool); + return_unused_pool_pebs(ubi, &ubi->fm_wl_pool); + + if (ubi->fm) { + for (i = 0; i < ubi->fm->used_blocks; i++) + kfree(ubi->fm->e[i]); + } + kfree(ubi->fm); +} + +/** + * may_reserve_for_fm - tests whether a PEB shall be reserved for fastmap. + * See find_mean_wl_entry() + * + * @ubi: UBI device description object + * @e: physical eraseblock to return + * @root: RB tree to test against. + */ +static struct ubi_wl_entry *may_reserve_for_fm(struct ubi_device *ubi, + struct ubi_wl_entry *e, + struct rb_root *root) { + if (e && !ubi->fm_disabled && !ubi->fm && + e->pnum < UBI_FM_MAX_START) + e = rb_entry(rb_next(root->rb_node), + struct ubi_wl_entry, u.rb); + + return e; +} -- cgit v1.2.3-54-g00ecf