[deliverable/linux.git] / drivers / mtd / ubi / fastmap-wl.c

/*
 * Copyright (c) 2012 Linutronix GmbH
 * Copyright (c) 2014 sigma star gmbh
 * Author: Richard Weinberger <richard@nod.at>
 *
 * 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;
}
Commit	Line	Data
78d6d497 RW	1	/*
	2	* Copyright (c) 2012 Linutronix GmbH
	3	* Copyright (c) 2014 sigma star gmbh
	4	* Author: Richard Weinberger <richard@nod.at>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; version 2.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
	13	* the GNU General Public License for more details.
	14	*
	15	*/
	16
	17	/**
	18	* update_fastmap_work_fn - calls ubi_update_fastmap from a work queue
	19	* @wrk: the work description object
	20	*/
	21	static void update_fastmap_work_fn(struct work_struct *wrk)
	22	{
	23	struct ubi_device *ubi = container_of(wrk, struct ubi_device, fm_work);
1841fcfd	24
78d6d497 RW	25	ubi_update_fastmap(ubi);
	26	spin_lock(&ubi->wl_lock);
	27	ubi->fm_work_scheduled = 0;
	28	spin_unlock(&ubi->wl_lock);
	29	}
	30
78d6d497 RW	31	/**
	32	* find_anchor_wl_entry - find wear-leveling entry to used as anchor PEB.
	33	* @root: the RB-tree where to look for
	34	*/
	35	static struct ubi_wl_entry find_anchor_wl_entry(struct rb_root root)
	36	{
	37	struct rb_node *p;
	38	struct ubi_wl_entry e, victim = NULL;
	39	int max_ec = UBI_MAX_ERASECOUNTER;
	40
	41	ubi_rb_for_each_entry(p, e, root, u.rb) {
	42	if (e->pnum < UBI_FM_MAX_START && e->ec < max_ec) {
	43	victim = e;
	44	max_ec = e->ec;
	45	}
	46	}
	47
	48	return victim;
	49	}
	50
	51	/**
	52	* return_unused_pool_pebs - returns unused PEB to the free tree.
	53	* @ubi: UBI device description object
	54	* @pool: fastmap pool description object
	55	*/
	56	static void return_unused_pool_pebs(struct ubi_device *ubi,
	57	struct ubi_fm_pool *pool)
	58	{
	59	int i;
	60	struct ubi_wl_entry *e;
	61
	62	for (i = pool->used; i < pool->size; i++) {
	63	e = ubi->lookuptbl[pool->pebs[i]];
	64	wl_tree_add(e, &ubi->free);
	65	ubi->free_count++;
	66	}
	67	}
	68
	69	static int anchor_pebs_avalible(struct rb_root *root)
	70	{
	71	struct rb_node *p;
	72	struct ubi_wl_entry *e;
	73
	74	ubi_rb_for_each_entry(p, e, root, u.rb)
	75	if (e->pnum < UBI_FM_MAX_START)
	76	return 1;
	77
	78	return 0;
	79	}
	80
	81	/**
	82	* ubi_wl_get_fm_peb - find a physical erase block with a given maximal number.
	83	* @ubi: UBI device description object
	84	* @anchor: This PEB will be used as anchor PEB by fastmap
	85	*
	86	* The function returns a physical erase block with a given maximal number
	87	* and removes it from the wl subsystem.
	88	* Must be called with wl_lock held!
	89	*/
	90	struct ubi_wl_entry ubi_wl_get_fm_peb(struct ubi_device ubi, int anchor)
	91	{
	92	struct ubi_wl_entry *e = NULL;
	93
	94	if (!ubi->free.rb_node \|\| (ubi->free_count - ubi->beb_rsvd_pebs < 1))
95	goto out;
96
97	if (anchor)
98	e = find_anchor_wl_entry(&ubi->free);
99	else
100	e = find_mean_wl_entry(ubi, &ubi->free);
101
102	if (!e)
103	goto out;
104
105	self_check_in_wl_tree(ubi, e, &ubi->free);
106
107	/* remove it from the free list,
108	* the wl subsystem does no longer know this erase block */
109	rb_erase(&e->u.rb, &ubi->free);
110	ubi->free_count--;
111	out:
112	return e;
113	}
114
115	/**
116	* ubi_refill_pools - refills all fastmap PEB pools.
117	* @ubi: UBI device description object
118	*/
119	void ubi_refill_pools(struct ubi_device *ubi)
120	{
121	struct ubi_fm_pool *wl_pool = &ubi->fm_wl_pool;
122	struct ubi_fm_pool *pool = &ubi->fm_pool;
123	struct ubi_wl_entry *e;
124	int enough;
125
126	spin_lock(&ubi->wl_lock);
127
128	return_unused_pool_pebs(ubi, wl_pool);
129	return_unused_pool_pebs(ubi, pool);
130
131	wl_pool->size = 0;
132	pool->size = 0;
133
134	for (;;) {
135	enough = 0;
136	if (pool->size < pool->max_size) {
137	if (!ubi->free.rb_node)
138	break;
139
140	e = wl_get_wle(ubi);
141	if (!e)
142	break;
143
144	pool->pebs[pool->size] = e->pnum;
145	pool->size++;
146	} else
147	enough++;
148
149	if (wl_pool->size < wl_pool->max_size) {
150	if (!ubi->free.rb_node \|\|
151	(ubi->free_count - ubi->beb_rsvd_pebs < 5))
152	break;
153
154	e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
155	self_check_in_wl_tree(ubi, e, &ubi->free);
156	rb_erase(&e->u.rb, &ubi->free);
157	ubi->free_count--;
158
159	wl_pool->pebs[wl_pool->size] = e->pnum;
160	wl_pool->size++;
161	} else
162	enough++;
163
164	if (enough == 2)
165	break;
166	}
167
168	wl_pool->used = 0;
169	pool->used = 0;
170
171	spin_unlock(&ubi->wl_lock);
172	}
173
174	/**
175	* ubi_wl_get_peb - get a physical eraseblock.
176	* @ubi: UBI device description object
177	*
178	* This function returns a physical eraseblock in case of success and a
179	* negative error code in case of failure.
180	* Returns with ubi->fm_eba_sem held in read mode!
181	*/
182	int ubi_wl_get_peb(struct ubi_device *ubi)
183	{
184	int ret, retried = 0;
185	struct ubi_fm_pool *pool = &ubi->fm_pool;
186	struct ubi_fm_pool *wl_pool = &ubi->fm_wl_pool;
187
188	again:
189	down_read(&ubi->fm_eba_sem);
190	spin_lock(&ubi->wl_lock);
191
192	/* We check here also for the WL pool because at this point we can
193	* refill the WL pool synchronous. */
194	if (pool->used == pool->size \|\| wl_pool->used == wl_pool->size) {
195	spin_unlock(&ubi->wl_lock);
196	up_read(&ubi->fm_eba_sem);
197	ret = ubi_update_fastmap(ubi);
198	if (ret) {
199	ubi_msg(ubi, "Unable to write a new fastmap: %i", ret);
200	down_read(&ubi->fm_eba_sem);
201	return -ENOSPC;
202	}
203	down_read(&ubi->fm_eba_sem);
204	spin_lock(&ubi->wl_lock);
205	}
206
207	if (pool->used == pool->size) {
208	spin_unlock(&ubi->wl_lock);
209	if (retried) {
210	ubi_err(ubi, "Unable to get a free PEB from user WL pool");
211	ret = -ENOSPC;
212	goto out;
213	}
214	retried = 1;
215	up_read(&ubi->fm_eba_sem);
216	goto again;
217	}
218
219	ubi_assert(pool->used < pool->size);
220	ret = pool->pebs[pool->used++];
221	prot_queue_add(ubi, ubi->lookuptbl[ret]);
222	spin_unlock(&ubi->wl_lock);
223	out:
224	return ret;
225	}
226
227	/* get_peb_for_wl - returns a PEB to be used internally by the WL sub-system.
228	*
229	* @ubi: UBI device description object
230	*/
231	static struct ubi_wl_entry get_peb_for_wl(struct ubi_device ubi)
232	{
233	struct ubi_fm_pool *pool = &ubi->fm_wl_pool;
234	int pnum;
235
236	if (pool->used == pool->size) {
237	/* We cannot update the fastmap here because this
238	* function is called in atomic context.
239	* Let's fail here and refill/update it as soon as possible. */
240	if (!ubi->fm_work_scheduled) {
241	ubi->fm_work_scheduled = 1;
242	schedule_work(&ubi->fm_work);
243	}
244	return NULL;
78d6d497	245	}
e1bc37ce RW	246
	247	pnum = pool->pebs[pool->used++];
	248	return ubi->lookuptbl[pnum];
78d6d497 RW	249	}
	250
	251	/**
	252	* ubi_ensure_anchor_pebs - schedule wear-leveling to produce an anchor PEB.
	253	* @ubi: UBI device description object
	254	*/
	255	int ubi_ensure_anchor_pebs(struct ubi_device *ubi)
	256	{
	257	struct ubi_work *wrk;
	258
	259	spin_lock(&ubi->wl_lock);
	260	if (ubi->wl_scheduled) {
	261	spin_unlock(&ubi->wl_lock);
	262	return 0;
	263	}
	264	ubi->wl_scheduled = 1;
	265	spin_unlock(&ubi->wl_lock);
	266
	267	wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
	268	if (!wrk) {
	269	spin_lock(&ubi->wl_lock);
	270	ubi->wl_scheduled = 0;
	271	spin_unlock(&ubi->wl_lock);
	272	return -ENOMEM;
	273	}
	274
	275	wrk->anchor = 1;
	276	wrk->func = &wear_leveling_worker;
	277	schedule_ubi_work(ubi, wrk);
	278	return 0;
	279	}
	280
	281	/**
	282	* ubi_wl_put_fm_peb - returns a PEB used in a fastmap to the wear-leveling
	283	* sub-system.
	284	* see: ubi_wl_put_peb()
	285	*
	286	* @ubi: UBI device description object
	287	* @fm_e: physical eraseblock to return
	288	* @lnum: the last used logical eraseblock number for the PEB
	289	* @torture: if this physical eraseblock has to be tortured
	290	*/
	291	int ubi_wl_put_fm_peb(struct ubi_device ubi, struct ubi_wl_entry fm_e,
	292	int lnum, int torture)
	293	{
	294	struct ubi_wl_entry *e;
	295	int vol_id, pnum = fm_e->pnum;
	296
	297	dbg_wl("PEB %d", pnum);
	298
	299	ubi_assert(pnum >= 0);
	300	ubi_assert(pnum < ubi->peb_count);
	301
	302	spin_lock(&ubi->wl_lock);
	303	e = ubi->lookuptbl[pnum];
	304
	305	/* This can happen if we recovered from a fastmap the very
	306	* first time and writing now a new one. In this case the wl system
	307	* has never seen any PEB used by the original fastmap.
	308	*/
	309	if (!e) {
	310	e = fm_e;
	311	ubi_assert(e->ec >= 0);
	312	ubi->lookuptbl[pnum] = e;
313	}
314
315	spin_unlock(&ubi->wl_lock);
316
317	vol_id = lnum ? UBI_FM_DATA_VOLUME_ID : UBI_FM_SB_VOLUME_ID;
318	return schedule_erase(ubi, e, vol_id, lnum, torture);
319	}
320
321	/**
322	* ubi_is_erase_work - checks whether a work is erase work.
323	* @wrk: The work object to be checked
324	*/
325	int ubi_is_erase_work(struct ubi_work *wrk)
326	{
327	return wrk->func == erase_worker;
328	}
329
330	static void ubi_fastmap_close(struct ubi_device *ubi)
331	{
332	int i;
333
334	flush_work(&ubi->fm_work);
335	return_unused_pool_pebs(ubi, &ubi->fm_pool);
336	return_unused_pool_pebs(ubi, &ubi->fm_wl_pool);
337
338	if (ubi->fm) {
339	for (i = 0; i < ubi->fm->used_blocks; i++)
340	kfree(ubi->fm->e[i]);
341	}
342	kfree(ubi->fm);
343	}
2f84c246 RW	344
	345	/**
	346	* may_reserve_for_fm - tests whether a PEB shall be reserved for fastmap.
	347	* See find_mean_wl_entry()
	348	*
	349	* @ubi: UBI device description object
	350	* @e: physical eraseblock to return
	351	* @root: RB tree to test against.
	352	*/
	353	static struct ubi_wl_entry may_reserve_for_fm(struct ubi_device ubi,
	354	struct ubi_wl_entry *e,
	355	struct rb_root *root) {
	356	if (e && !ubi->fm_disabled && !ubi->fm &&
	357	e->pnum < UBI_FM_MAX_START)
	358	e = rb_entry(rb_next(root->rb_node),
	359	struct ubi_wl_entry, u.rb);
	360
	361	return e;
	362	}