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