summaryrefslogtreecommitdiff
path: root/drivers/mtd/ubi/fastmap-wl.c
blob: d9e2e3a6e105fd4885f3812f8e20a6c10e823846 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2012 Linutronix GmbH
 * Copyright (c) 2014 sigma star gmbh
 * Author: Richard Weinberger <richard@nod.at>
 */

/**
 * 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_available(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);
}

/**
 * produce_free_peb - produce a free physical eraseblock.
 * @ubi: UBI device description object
 *
 * This function tries to make a free PEB by means of synchronous execution of
 * pending works. This may be needed if, for example the background thread is
 * disabled. Returns zero in case of success and a negative error code in case
 * of failure.
 */
static int produce_free_peb(struct ubi_device *ubi)
{
	int err;

	while (!ubi->free.rb_node && ubi->works_count) {
		dbg_wl("do one work synchronously");
		err = do_work(ubi);

		if (err)
			return err;
	}

	return 0;
}

/**
 * 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);
		ret = produce_free_peb(ubi);
		if (ret < 0) {
			down_read(&ubi->fm_eba_sem);
			goto out;
		}
		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;

	ubi_assert(rwsem_is_locked(&ubi->fm_eba_sem));

	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, true);
}

/**
 * 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;
}