text: /*
   * Copyright (c) 2012 Linutronix GmbH
   * Copyright (c) 2014 sigma star gmbh
   * Author: Richard Weinberger <richard@nod.at>
   *
   * SPDX-License-Identifier:	GPL-2.0+
   *
   */
  
  /**
   * update_fastmap_work_fn - calls ubi_update_fastmap from a work queue
   * @wrk: the work description object
   */
  #ifndef __UBOOT__
  static void update_fastmap_work_fn(struct work_struct *wrk)
  #else
  void update_fastmap_work_fn(struct ubi_device *ubi)
  #endif
  {
  #ifndef __UBOOT__
  	struct ubi_device *ubi = container_of(wrk, struct ubi_device, fm_work);
  #endif
  
  	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) {
  #ifndef __UBOOT__
  		/* 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;
  #else
  		/*
  		 * No work queues in U-Boot, we must do this immediately
  		 */
  		update_fastmap_work_fn(ubi);
  #endif
  	}
  
  	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;
  
  	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;
  }
  