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Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[cris-mirror.git] / drivers / mtd / mtdswap.c
blob7eb0e1f4f9803ad3f9f00b296eb21388447f341e
1 /*
2 * Swap block device support for MTDs
3 * Turns an MTD device into a swap device with block wear leveling
4 *
5 * Copyright © 2007,2011 Nokia Corporation. All rights reserved.
6 *
7 * Authors: Jarkko Lavinen <jarkko.lavinen@nokia.com>
8 *
9 * Based on Richard Purdie's earlier implementation in 2007. Background
10 * support and lock-less operation written by Adrian Hunter.
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * version 2 as published by the Free Software Foundation.
15 *
16 * This program is distributed in the hope that it will be useful, but
17 * WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
24 * 02110-1301 USA
25 */
26
27 #include <linux/kernel.h>
28 #include <linux/module.h>
29 #include <linux/mtd/mtd.h>
30 #include <linux/mtd/blktrans.h>
31 #include <linux/rbtree.h>
32 #include <linux/sched.h>
33 #include <linux/slab.h>
34 #include <linux/vmalloc.h>
35 #include <linux/genhd.h>
36 #include <linux/swap.h>
37 #include <linux/debugfs.h>
38 #include <linux/seq_file.h>
39 #include <linux/device.h>
40 #include <linux/math64.h>
41
42 #define MTDSWAP_PREFIX "mtdswap"
43
44 /*
45 * The number of free eraseblocks when GC should stop
46 */
47 #define CLEAN_BLOCK_THRESHOLD 20
48
49 /*
50 * Number of free eraseblocks below which GC can also collect low frag
51 * blocks.
52 */
53 #define LOW_FRAG_GC_THRESHOLD 5
54
55 /*
56 * Wear level cost amortization. We want to do wear leveling on the background
57 * without disturbing gc too much. This is made by defining max GC frequency.
58 * Frequency value 6 means 1/6 of the GC passes will pick an erase block based
59 * on the biggest wear difference rather than the biggest dirtiness.
60 *
61 * The lower freq2 should be chosen so that it makes sure the maximum erase
62 * difference will decrease even if a malicious application is deliberately
63 * trying to make erase differences large.
64 */
65 #define MAX_ERASE_DIFF 4000
66 #define COLLECT_NONDIRTY_BASE MAX_ERASE_DIFF
67 #define COLLECT_NONDIRTY_FREQ1 6
68 #define COLLECT_NONDIRTY_FREQ2 4
69
70 #define PAGE_UNDEF UINT_MAX
71 #define BLOCK_UNDEF UINT_MAX
72 #define BLOCK_ERROR (UINT_MAX - 1)
73 #define BLOCK_MAX (UINT_MAX - 2)
74
75 #define EBLOCK_BAD (1 << 0)
76 #define EBLOCK_NOMAGIC (1 << 1)
77 #define EBLOCK_BITFLIP (1 << 2)
78 #define EBLOCK_FAILED (1 << 3)
79 #define EBLOCK_READERR (1 << 4)
80 #define EBLOCK_IDX_SHIFT 5
81
82 struct swap_eb {
83 struct rb_node rb;
84 struct rb_root *root;
85
86 unsigned int flags;
87 unsigned int active_count;
88 unsigned int erase_count;
89 unsigned int pad; /* speeds up pointer decrement */
90 };
91
92 #define MTDSWAP_ECNT_MIN(rbroot) (rb_entry(rb_first(rbroot), struct swap_eb, \
93 rb)->erase_count)
94 #define MTDSWAP_ECNT_MAX(rbroot) (rb_entry(rb_last(rbroot), struct swap_eb, \
95 rb)->erase_count)
96
97 struct mtdswap_tree {
98 struct rb_root root;
99 unsigned int count;
100 };
101
102 enum {
103 MTDSWAP_CLEAN,
104 MTDSWAP_USED,
105 MTDSWAP_LOWFRAG,
106 MTDSWAP_HIFRAG,
107 MTDSWAP_DIRTY,
108 MTDSWAP_BITFLIP,
109 MTDSWAP_FAILING,
110 MTDSWAP_TREE_CNT,
111 };
112
113 struct mtdswap_dev {
114 struct mtd_blktrans_dev *mbd_dev;
115 struct mtd_info *mtd;
116 struct device *dev;
117
118 unsigned int *page_data;
119 unsigned int *revmap;
120
121 unsigned int eblks;
122 unsigned int spare_eblks;
123 unsigned int pages_per_eblk;
124 unsigned int max_erase_count;
125 struct swap_eb *eb_data;
126
127 struct mtdswap_tree trees[MTDSWAP_TREE_CNT];
128
129 unsigned long long sect_read_count;
130 unsigned long long sect_write_count;
131 unsigned long long mtd_write_count;
132 unsigned long long mtd_read_count;
133 unsigned long long discard_count;
134 unsigned long long discard_page_count;
135
136 unsigned int curr_write_pos;
137 struct swap_eb *curr_write;
138
139 char *page_buf;
140 char *oob_buf;
141 };
142
143 struct mtdswap_oobdata {
144 __le16 magic;
145 __le32 count;
146 } __packed;
147
148 #define MTDSWAP_MAGIC_CLEAN 0x2095
149 #define MTDSWAP_MAGIC_DIRTY (MTDSWAP_MAGIC_CLEAN + 1)
150 #define MTDSWAP_TYPE_CLEAN 0
151 #define MTDSWAP_TYPE_DIRTY 1
152 #define MTDSWAP_OOBSIZE sizeof(struct mtdswap_oobdata)
153
154 #define MTDSWAP_ERASE_RETRIES 3 /* Before marking erase block bad */
155 #define MTDSWAP_IO_RETRIES 3
156
157 enum {
158 MTDSWAP_SCANNED_CLEAN,
159 MTDSWAP_SCANNED_DIRTY,
160 MTDSWAP_SCANNED_BITFLIP,
161 MTDSWAP_SCANNED_BAD,
162 };
163
164 /*
165 * In the worst case mtdswap_writesect() has allocated the last clean
166 * page from the current block and is then pre-empted by the GC
167 * thread. The thread can consume a full erase block when moving a
168 * block.
169 */
170 #define MIN_SPARE_EBLOCKS 2
171 #define MIN_ERASE_BLOCKS (MIN_SPARE_EBLOCKS + 1)
172
173 #define TREE_ROOT(d, name) (&d->trees[MTDSWAP_ ## name].root)
174 #define TREE_EMPTY(d, name) (TREE_ROOT(d, name)->rb_node == NULL)
175 #define TREE_NONEMPTY(d, name) (!TREE_EMPTY(d, name))
176 #define TREE_COUNT(d, name) (d->trees[MTDSWAP_ ## name].count)
177
178 #define MTDSWAP_MBD_TO_MTDSWAP(dev) ((struct mtdswap_dev *)dev->priv)
179
180 static char partitions[128] = "";
181 module_param_string(partitions, partitions, sizeof(partitions), 0444);
182 MODULE_PARM_DESC(partitions, "MTD partition numbers to use as swap "
183 "partitions=\"1,3,5\"");
184
185 static unsigned int spare_eblocks = 10;
186 module_param(spare_eblocks, uint, 0444);
187 MODULE_PARM_DESC(spare_eblocks, "Percentage of spare erase blocks for "
188 "garbage collection (default 10%)");
189
190 static bool header; /* false */
191 module_param(header, bool, 0444);
192 MODULE_PARM_DESC(header,
193 "Include builtin swap header (default 0, without header)");
194
195 static int mtdswap_gc(struct mtdswap_dev *d, unsigned int background);
196
197 static loff_t mtdswap_eb_offset(struct mtdswap_dev *d, struct swap_eb *eb)
198 {
199 return (loff_t)(eb - d->eb_data) * d->mtd->erasesize;
200 }
201
202 static void mtdswap_eb_detach(struct mtdswap_dev *d, struct swap_eb *eb)
203 {
204 unsigned int oldidx;
205 struct mtdswap_tree *tp;
206
207 if (eb->root) {
208 tp = container_of(eb->root, struct mtdswap_tree, root);
209 oldidx = tp - &d->trees[0];
210
211 d->trees[oldidx].count--;
212 rb_erase(&eb->rb, eb->root);
213 }
214 }
215
216 static void __mtdswap_rb_add(struct rb_root *root, struct swap_eb *eb)
217 {
218 struct rb_node **p, *parent = NULL;
219 struct swap_eb *cur;
220
221 p = &root->rb_node;
222 while (*p) {
223 parent = *p;
224 cur = rb_entry(parent, struct swap_eb, rb);
225 if (eb->erase_count > cur->erase_count)
226 p = &(*p)->rb_right;
227 else
228 p = &(*p)->rb_left;
229 }
230
231 rb_link_node(&eb->rb, parent, p);
232 rb_insert_color(&eb->rb, root);
233 }
234
235 static void mtdswap_rb_add(struct mtdswap_dev *d, struct swap_eb *eb, int idx)
236 {
237 struct rb_root *root;
238
239 if (eb->root == &d->trees[idx].root)
240 return;
241
242 mtdswap_eb_detach(d, eb);
243 root = &d->trees[idx].root;
244 __mtdswap_rb_add(root, eb);
245 eb->root = root;
246 d->trees[idx].count++;
247 }
248
249 static struct rb_node *mtdswap_rb_index(struct rb_root *root, unsigned int idx)
250 {
251 struct rb_node *p;
252 unsigned int i;
253
254 p = rb_first(root);
255 i = 0;
256 while (i < idx && p) {
257 p = rb_next(p);
258 i++;
259 }
260
261 return p;
262 }
263
264 static int mtdswap_handle_badblock(struct mtdswap_dev *d, struct swap_eb *eb)
265 {
266 int ret;
267 loff_t offset;
268
269 d->spare_eblks--;
270 eb->flags |= EBLOCK_BAD;
271 mtdswap_eb_detach(d, eb);
272 eb->root = NULL;
273
274 /* badblocks not supported */
275 if (!mtd_can_have_bb(d->mtd))
276 return 1;
277
278 offset = mtdswap_eb_offset(d, eb);
279 dev_warn(d->dev, "Marking bad block at %08llx\n", offset);
280 ret = mtd_block_markbad(d->mtd, offset);
281
282 if (ret) {
283 dev_warn(d->dev, "Mark block bad failed for block at %08llx "
284 "error %d\n", offset, ret);
285 return ret;
286 }
287
288 return 1;
289
290 }
291
292 static int mtdswap_handle_write_error(struct mtdswap_dev *d, struct swap_eb *eb)
293 {
294 unsigned int marked = eb->flags & EBLOCK_FAILED;
295 struct swap_eb *curr_write = d->curr_write;
296
297 eb->flags |= EBLOCK_FAILED;
298 if (curr_write == eb) {
299 d->curr_write = NULL;
300
301 if (!marked && d->curr_write_pos != 0) {
302 mtdswap_rb_add(d, eb, MTDSWAP_FAILING);
303 return 0;
304 }
305 }
306
307 return mtdswap_handle_badblock(d, eb);
308 }
309
310 static int mtdswap_read_oob(struct mtdswap_dev *d, loff_t from,
311 struct mtd_oob_ops *ops)
312 {
313 int ret = mtd_read_oob(d->mtd, from, ops);
314
315 if (mtd_is_bitflip(ret))
316 return ret;
317
318 if (ret) {
319 dev_warn(d->dev, "Read OOB failed %d for block at %08llx\n",
320 ret, from);
321 return ret;
322 }
323
324 if (ops->oobretlen < ops->ooblen) {
325 dev_warn(d->dev, "Read OOB return short read (%zd bytes not "
326 "%zd) for block at %08llx\n",
327 ops->oobretlen, ops->ooblen, from);
328 return -EIO;
329 }
330
331 return 0;
332 }
333
334 static int mtdswap_read_markers(struct mtdswap_dev *d, struct swap_eb *eb)
335 {
336 struct mtdswap_oobdata *data, *data2;
337 int ret;
338 loff_t offset;
339 struct mtd_oob_ops ops;
340
341 offset = mtdswap_eb_offset(d, eb);
342
343 /* Check first if the block is bad. */
344 if (mtd_can_have_bb(d->mtd) && mtd_block_isbad(d->mtd, offset))
345 return MTDSWAP_SCANNED_BAD;
346
347 ops.ooblen = 2 * d->mtd->oobavail;
348 ops.oobbuf = d->oob_buf;
349 ops.ooboffs = 0;
350 ops.datbuf = NULL;
351 ops.mode = MTD_OPS_AUTO_OOB;
352
353 ret = mtdswap_read_oob(d, offset, &ops);
354
355 if (ret && !mtd_is_bitflip(ret))
356 return ret;
357
358 data = (struct mtdswap_oobdata *)d->oob_buf;
359 data2 = (struct mtdswap_oobdata *)
360 (d->oob_buf + d->mtd->oobavail);
361
362 if (le16_to_cpu(data->magic) == MTDSWAP_MAGIC_CLEAN) {
363 eb->erase_count = le32_to_cpu(data->count);
364 if (mtd_is_bitflip(ret))
365 ret = MTDSWAP_SCANNED_BITFLIP;
366 else {
367 if (le16_to_cpu(data2->magic) == MTDSWAP_MAGIC_DIRTY)
368 ret = MTDSWAP_SCANNED_DIRTY;
369 else
370 ret = MTDSWAP_SCANNED_CLEAN;
371 }
372 } else {
373 eb->flags |= EBLOCK_NOMAGIC;
374 ret = MTDSWAP_SCANNED_DIRTY;
375 }
376
377 return ret;
378 }
379
380 static int mtdswap_write_marker(struct mtdswap_dev *d, struct swap_eb *eb,
381 u16 marker)
382 {
383 struct mtdswap_oobdata n;
384 int ret;
385 loff_t offset;
386 struct mtd_oob_ops ops;
387
388 ops.ooboffs = 0;
389 ops.oobbuf = (uint8_t *)&n;
390 ops.mode = MTD_OPS_AUTO_OOB;
391 ops.datbuf = NULL;
392
393 if (marker == MTDSWAP_TYPE_CLEAN) {
394 n.magic = cpu_to_le16(MTDSWAP_MAGIC_CLEAN);
395 n.count = cpu_to_le32(eb->erase_count);
396 ops.ooblen = MTDSWAP_OOBSIZE;
397 offset = mtdswap_eb_offset(d, eb);
398 } else {
399 n.magic = cpu_to_le16(MTDSWAP_MAGIC_DIRTY);
400 ops.ooblen = sizeof(n.magic);
401 offset = mtdswap_eb_offset(d, eb) + d->mtd->writesize;
402 }
403
404 ret = mtd_write_oob(d->mtd, offset, &ops);
405
406 if (ret) {
407 dev_warn(d->dev, "Write OOB failed for block at %08llx "
408 "error %d\n", offset, ret);
409 if (ret == -EIO || mtd_is_eccerr(ret))
410 mtdswap_handle_write_error(d, eb);
411 return ret;
412 }
413
414 if (ops.oobretlen != ops.ooblen) {
415 dev_warn(d->dev, "Short OOB write for block at %08llx: "
416 "%zd not %zd\n",
417 offset, ops.oobretlen, ops.ooblen);
418 return ret;
419 }
420
421 return 0;
422 }
423
424 /*
425 * Are there any erase blocks without MAGIC_CLEAN header, presumably
426 * because power was cut off after erase but before header write? We
427 * need to guestimate the erase count.
428 */
429 static void mtdswap_check_counts(struct mtdswap_dev *d)
430 {
431 struct rb_root hist_root = RB_ROOT;
432 struct rb_node *medrb;
433 struct swap_eb *eb;
434 unsigned int i, cnt, median;
435
436 cnt = 0;
437 for (i = 0; i < d->eblks; i++) {
438 eb = d->eb_data + i;
439
440 if (eb->flags & (EBLOCK_NOMAGIC | EBLOCK_BAD | EBLOCK_READERR))
441 continue;
442
443 __mtdswap_rb_add(&hist_root, eb);
444 cnt++;
445 }
446
447 if (cnt == 0)
448 return;
449
450 medrb = mtdswap_rb_index(&hist_root, cnt / 2);
451 median = rb_entry(medrb, struct swap_eb, rb)->erase_count;
452
453 d->max_erase_count = MTDSWAP_ECNT_MAX(&hist_root);
454
455 for (i = 0; i < d->eblks; i++) {
456 eb = d->eb_data + i;
457
458 if (eb->flags & (EBLOCK_NOMAGIC | EBLOCK_READERR))
459 eb->erase_count = median;
460
461 if (eb->flags & (EBLOCK_NOMAGIC | EBLOCK_BAD | EBLOCK_READERR))
462 continue;
463
464 rb_erase(&eb->rb, &hist_root);
465 }
466 }
467
468 static void mtdswap_scan_eblks(struct mtdswap_dev *d)
469 {
470 int status;
471 unsigned int i, idx;
472 struct swap_eb *eb;
473
474 for (i = 0; i < d->eblks; i++) {
475 eb = d->eb_data + i;
476
477 status = mtdswap_read_markers(d, eb);
478 if (status < 0)
479 eb->flags |= EBLOCK_READERR;
480 else if (status == MTDSWAP_SCANNED_BAD) {
481 eb->flags |= EBLOCK_BAD;
482 continue;
483 }
484
485 switch (status) {
486 case MTDSWAP_SCANNED_CLEAN:
487 idx = MTDSWAP_CLEAN;
488 break;
489 case MTDSWAP_SCANNED_DIRTY:
490 case MTDSWAP_SCANNED_BITFLIP:
491 idx = MTDSWAP_DIRTY;
492 break;
493 default:
494 idx = MTDSWAP_FAILING;
495 }
496
497 eb->flags |= (idx << EBLOCK_IDX_SHIFT);
498 }
499
500 mtdswap_check_counts(d);
501
502 for (i = 0; i < d->eblks; i++) {
503 eb = d->eb_data + i;
504
505 if (eb->flags & EBLOCK_BAD)
506 continue;
507
508 idx = eb->flags >> EBLOCK_IDX_SHIFT;
509 mtdswap_rb_add(d, eb, idx);
510 }
511 }
512
513 /*
514 * Place eblk into a tree corresponding to its number of active blocks
515 * it contains.
516 */
517 static void mtdswap_store_eb(struct mtdswap_dev *d, struct swap_eb *eb)
518 {
519 unsigned int weight = eb->active_count;
520 unsigned int maxweight = d->pages_per_eblk;
521
522 if (eb == d->curr_write)
523 return;
524
525 if (eb->flags & EBLOCK_BITFLIP)
526 mtdswap_rb_add(d, eb, MTDSWAP_BITFLIP);
527 else if (eb->flags & (EBLOCK_READERR | EBLOCK_FAILED))
528 mtdswap_rb_add(d, eb, MTDSWAP_FAILING);
529 if (weight == maxweight)
530 mtdswap_rb_add(d, eb, MTDSWAP_USED);
531 else if (weight == 0)
532 mtdswap_rb_add(d, eb, MTDSWAP_DIRTY);
533 else if (weight > (maxweight/2))
534 mtdswap_rb_add(d, eb, MTDSWAP_LOWFRAG);
535 else
536 mtdswap_rb_add(d, eb, MTDSWAP_HIFRAG);
537 }
538
539
540 static void mtdswap_erase_callback(struct erase_info *done)
541 {
542 wait_queue_head_t *wait_q = (wait_queue_head_t *)done->priv;
543 wake_up(wait_q);
544 }
545
546 static int mtdswap_erase_block(struct mtdswap_dev *d, struct swap_eb *eb)
547 {
548 struct mtd_info *mtd = d->mtd;
549 struct erase_info erase;
550 wait_queue_head_t wq;
551 unsigned int retries = 0;
552 int ret;
553
554 eb->erase_count++;
555 if (eb->erase_count > d->max_erase_count)
556 d->max_erase_count = eb->erase_count;
557
558 retry:
559 init_waitqueue_head(&wq);
560 memset(&erase, 0, sizeof(struct erase_info));
561
562 erase.mtd = mtd;
563 erase.callback = mtdswap_erase_callback;
564 erase.addr = mtdswap_eb_offset(d, eb);
565 erase.len = mtd->erasesize;
566 erase.priv = (u_long)&wq;
567
568 ret = mtd_erase(mtd, &erase);
569 if (ret) {
570 if (retries++ < MTDSWAP_ERASE_RETRIES) {
571 dev_warn(d->dev,
572 "erase of erase block %#llx on %s failed",
573 erase.addr, mtd->name);
574 yield();
575 goto retry;
576 }
577
578 dev_err(d->dev, "Cannot erase erase block %#llx on %s\n",
579 erase.addr, mtd->name);
580
581 mtdswap_handle_badblock(d, eb);
582 return -EIO;
583 }
584
585 ret = wait_event_interruptible(wq, erase.state == MTD_ERASE_DONE ||
586 erase.state == MTD_ERASE_FAILED);
587 if (ret) {
588 dev_err(d->dev, "Interrupted erase block %#llx erasure on %s\n",
589 erase.addr, mtd->name);
590 return -EINTR;
591 }
592
593 if (erase.state == MTD_ERASE_FAILED) {
594 if (retries++ < MTDSWAP_ERASE_RETRIES) {
595 dev_warn(d->dev,
596 "erase of erase block %#llx on %s failed",
597 erase.addr, mtd->name);
598 yield();
599 goto retry;
600 }
601
602 mtdswap_handle_badblock(d, eb);
603 return -EIO;
604 }
605
606 return 0;
607 }
608
609 static int mtdswap_map_free_block(struct mtdswap_dev *d, unsigned int page,
610 unsigned int *block)
611 {
612 int ret;
613 struct swap_eb *old_eb = d->curr_write;
614 struct rb_root *clean_root;
615 struct swap_eb *eb;
616
617 if (old_eb == NULL || d->curr_write_pos >= d->pages_per_eblk) {
618 do {
619 if (TREE_EMPTY(d, CLEAN))
620 return -ENOSPC;
621
622 clean_root = TREE_ROOT(d, CLEAN);
623 eb = rb_entry(rb_first(clean_root), struct swap_eb, rb);
624 rb_erase(&eb->rb, clean_root);
625 eb->root = NULL;
626 TREE_COUNT(d, CLEAN)--;
627
628 ret = mtdswap_write_marker(d, eb, MTDSWAP_TYPE_DIRTY);
629 } while (ret == -EIO || mtd_is_eccerr(ret));
630
631 if (ret)
632 return ret;
633
634 d->curr_write_pos = 0;
635 d->curr_write = eb;
636 if (old_eb)
637 mtdswap_store_eb(d, old_eb);
638 }
639
640 *block = (d->curr_write - d->eb_data) * d->pages_per_eblk +
641 d->curr_write_pos;
642
643 d->curr_write->active_count++;
644 d->revmap[*block] = page;
645 d->curr_write_pos++;
646
647 return 0;
648 }
649
650 static unsigned int mtdswap_free_page_cnt(struct mtdswap_dev *d)
651 {
652 return TREE_COUNT(d, CLEAN) * d->pages_per_eblk +
653 d->pages_per_eblk - d->curr_write_pos;
654 }
655
656 static unsigned int mtdswap_enough_free_pages(struct mtdswap_dev *d)
657 {
658 return mtdswap_free_page_cnt(d) > d->pages_per_eblk;
659 }
660
661 static int mtdswap_write_block(struct mtdswap_dev *d, char *buf,
662 unsigned int page, unsigned int *bp, int gc_context)
663 {
664 struct mtd_info *mtd = d->mtd;
665 struct swap_eb *eb;
666 size_t retlen;
667 loff_t writepos;
668 int ret;
669
670 retry:
671 if (!gc_context)
672 while (!mtdswap_enough_free_pages(d))
673 if (mtdswap_gc(d, 0) > 0)
674 return -ENOSPC;
675
676 ret = mtdswap_map_free_block(d, page, bp);
677 eb = d->eb_data + (*bp / d->pages_per_eblk);
678
679 if (ret == -EIO || mtd_is_eccerr(ret)) {
680 d->curr_write = NULL;
681 eb->active_count--;
682 d->revmap[*bp] = PAGE_UNDEF;
683 goto retry;
684 }
685
686 if (ret < 0)
687 return ret;
688
689 writepos = (loff_t)*bp << PAGE_SHIFT;
690 ret = mtd_write(mtd, writepos, PAGE_SIZE, &retlen, buf);
691 if (ret == -EIO || mtd_is_eccerr(ret)) {
692 d->curr_write_pos--;
693 eb->active_count--;
694 d->revmap[*bp] = PAGE_UNDEF;
695 mtdswap_handle_write_error(d, eb);
696 goto retry;
697 }
698
699 if (ret < 0) {
700 dev_err(d->dev, "Write to MTD device failed: %d (%zd written)",
701 ret, retlen);
702 goto err;
703 }
704
705 if (retlen != PAGE_SIZE) {
706 dev_err(d->dev, "Short write to MTD device: %zd written",
707 retlen);
708 ret = -EIO;
709 goto err;
710 }
711
712 return ret;
713
714 err:
715 d->curr_write_pos--;
716 eb->active_count--;
717 d->revmap[*bp] = PAGE_UNDEF;
718
719 return ret;
720 }
721
722 static int mtdswap_move_block(struct mtdswap_dev *d, unsigned int oldblock,
723 unsigned int *newblock)
724 {
725 struct mtd_info *mtd = d->mtd;
726 struct swap_eb *eb, *oldeb;
727 int ret;
728 size_t retlen;
729 unsigned int page, retries;
730 loff_t readpos;
731
732 page = d->revmap[oldblock];
733 readpos = (loff_t) oldblock << PAGE_SHIFT;
734 retries = 0;
735
736 retry:
737 ret = mtd_read(mtd, readpos, PAGE_SIZE, &retlen, d->page_buf);
738
739 if (ret < 0 && !mtd_is_bitflip(ret)) {
740 oldeb = d->eb_data + oldblock / d->pages_per_eblk;
741 oldeb->flags |= EBLOCK_READERR;
742
743 dev_err(d->dev, "Read Error: %d (block %u)\n", ret,
744 oldblock);
745 retries++;
746 if (retries < MTDSWAP_IO_RETRIES)
747 goto retry;
748
749 goto read_error;
750 }
751
752 if (retlen != PAGE_SIZE) {
753 dev_err(d->dev, "Short read: %zd (block %u)\n", retlen,
754 oldblock);
755 ret = -EIO;
756 goto read_error;
757 }
758
759 ret = mtdswap_write_block(d, d->page_buf, page, newblock, 1);
760 if (ret < 0) {
761 d->page_data[page] = BLOCK_ERROR;
762 dev_err(d->dev, "Write error: %d\n", ret);
763 return ret;
764 }
765
766 eb = d->eb_data + *newblock / d->pages_per_eblk;
767 d->page_data[page] = *newblock;
768 d->revmap[oldblock] = PAGE_UNDEF;
769 eb = d->eb_data + oldblock / d->pages_per_eblk;
770 eb->active_count--;
771
772 return 0;
773
774 read_error:
775 d->page_data[page] = BLOCK_ERROR;
776 d->revmap[oldblock] = PAGE_UNDEF;
777 return ret;
778 }
779
780 static int mtdswap_gc_eblock(struct mtdswap_dev *d, struct swap_eb *eb)
781 {
782 unsigned int i, block, eblk_base, newblock;
783 int ret, errcode;
784
785 errcode = 0;
786 eblk_base = (eb - d->eb_data) * d->pages_per_eblk;
787
788 for (i = 0; i < d->pages_per_eblk; i++) {
789 if (d->spare_eblks < MIN_SPARE_EBLOCKS)
790 return -ENOSPC;
791
792 block = eblk_base + i;
793 if (d->revmap[block] == PAGE_UNDEF)
794 continue;
795
796 ret = mtdswap_move_block(d, block, &newblock);
797 if (ret < 0 && !errcode)
798 errcode = ret;
799 }
800
801 return errcode;
802 }
803
804 static int __mtdswap_choose_gc_tree(struct mtdswap_dev *d)
805 {
806 int idx, stopat;
807
808 if (TREE_COUNT(d, CLEAN) < LOW_FRAG_GC_THRESHOLD)
809 stopat = MTDSWAP_LOWFRAG;
810 else
811 stopat = MTDSWAP_HIFRAG;
812
813 for (idx = MTDSWAP_BITFLIP; idx >= stopat; idx--)
814 if (d->trees[idx].root.rb_node != NULL)
815 return idx;
816
817 return -1;
818 }
819
820 static int mtdswap_wlfreq(unsigned int maxdiff)
821 {
822 unsigned int h, x, y, dist, base;
823
824 /*
825 * Calculate linear ramp down from f1 to f2 when maxdiff goes from
826 * MAX_ERASE_DIFF to MAX_ERASE_DIFF + COLLECT_NONDIRTY_BASE. Similar
827 * to triangle with height f1 - f1 and width COLLECT_NONDIRTY_BASE.
828 */
829
830 dist = maxdiff - MAX_ERASE_DIFF;
831 if (dist > COLLECT_NONDIRTY_BASE)
832 dist = COLLECT_NONDIRTY_BASE;
833
834 /*
835 * Modelling the slop as right angular triangle with base
836 * COLLECT_NONDIRTY_BASE and height freq1 - freq2. The ratio y/x is
837 * equal to the ratio h/base.
838 */
839 h = COLLECT_NONDIRTY_FREQ1 - COLLECT_NONDIRTY_FREQ2;
840 base = COLLECT_NONDIRTY_BASE;
841
842 x = dist - base;
843 y = (x * h + base / 2) / base;
844
845 return COLLECT_NONDIRTY_FREQ2 + y;
846 }
847
848 static int mtdswap_choose_wl_tree(struct mtdswap_dev *d)
849 {
850 static unsigned int pick_cnt;
851 unsigned int i, idx = -1, wear, max;
852 struct rb_root *root;
853
854 max = 0;
855 for (i = 0; i <= MTDSWAP_DIRTY; i++) {
856 root = &d->trees[i].root;
857 if (root->rb_node == NULL)
858 continue;
859
860 wear = d->max_erase_count - MTDSWAP_ECNT_MIN(root);
861 if (wear > max) {
862 max = wear;
863 idx = i;
864 }
865 }
866
867 if (max > MAX_ERASE_DIFF && pick_cnt >= mtdswap_wlfreq(max) - 1) {
868 pick_cnt = 0;
869 return idx;
870 }
871
872 pick_cnt++;
873 return -1;
874 }
875
876 static int mtdswap_choose_gc_tree(struct mtdswap_dev *d,
877 unsigned int background)
878 {
879 int idx;
880
881 if (TREE_NONEMPTY(d, FAILING) &&
882 (background || (TREE_EMPTY(d, CLEAN) && TREE_EMPTY(d, DIRTY))))
883 return MTDSWAP_FAILING;
884
885 idx = mtdswap_choose_wl_tree(d);
886 if (idx >= MTDSWAP_CLEAN)
887 return idx;
888
889 return __mtdswap_choose_gc_tree(d);
890 }
891
892 static struct swap_eb *mtdswap_pick_gc_eblk(struct mtdswap_dev *d,
893 unsigned int background)
894 {
895 struct rb_root *rp = NULL;
896 struct swap_eb *eb = NULL;
897 int idx;
898
899 if (background && TREE_COUNT(d, CLEAN) > CLEAN_BLOCK_THRESHOLD &&
900 TREE_EMPTY(d, DIRTY) && TREE_EMPTY(d, FAILING))
901 return NULL;
902
903 idx = mtdswap_choose_gc_tree(d, background);
904 if (idx < 0)
905 return NULL;
906
907 rp = &d->trees[idx].root;
908 eb = rb_entry(rb_first(rp), struct swap_eb, rb);
909
910 rb_erase(&eb->rb, rp);
911 eb->root = NULL;
912 d->trees[idx].count--;
913 return eb;
914 }
915
916 static unsigned int mtdswap_test_patt(unsigned int i)
917 {
918 return i % 2 ? 0x55555555 : 0xAAAAAAAA;
919 }
920
921 static unsigned int mtdswap_eblk_passes(struct mtdswap_dev *d,
922 struct swap_eb *eb)
923 {
924 struct mtd_info *mtd = d->mtd;
925 unsigned int test, i, j, patt, mtd_pages;
926 loff_t base, pos;
927 unsigned int *p1 = (unsigned int *)d->page_buf;
928 unsigned char *p2 = (unsigned char *)d->oob_buf;
929 struct mtd_oob_ops ops;
930 int ret;
931
932 ops.mode = MTD_OPS_AUTO_OOB;
933 ops.len = mtd->writesize;
934 ops.ooblen = mtd->oobavail;
935 ops.ooboffs = 0;
936 ops.datbuf = d->page_buf;
937 ops.oobbuf = d->oob_buf;
938 base = mtdswap_eb_offset(d, eb);
939 mtd_pages = d->pages_per_eblk * PAGE_SIZE / mtd->writesize;
940
941 for (test = 0; test < 2; test++) {
942 pos = base;
943 for (i = 0; i < mtd_pages; i++) {
944 patt = mtdswap_test_patt(test + i);
945 memset(d->page_buf, patt, mtd->writesize);
946 memset(d->oob_buf, patt, mtd->oobavail);
947 ret = mtd_write_oob(mtd, pos, &ops);
948 if (ret)
949 goto error;
950
951 pos += mtd->writesize;
952 }
953
954 pos = base;
955 for (i = 0; i < mtd_pages; i++) {
956 ret = mtd_read_oob(mtd, pos, &ops);
957 if (ret)
958 goto error;
959
960 patt = mtdswap_test_patt(test + i);
961 for (j = 0; j < mtd->writesize/sizeof(int); j++)
962 if (p1[j] != patt)
963 goto error;
964
965 for (j = 0; j < mtd->oobavail; j++)
966 if (p2[j] != (unsigned char)patt)
967 goto error;
968
969 pos += mtd->writesize;
970 }
971
972 ret = mtdswap_erase_block(d, eb);
973 if (ret)
974 goto error;
975 }
976
977 eb->flags &= ~EBLOCK_READERR;
978 return 1;
979
980 error:
981 mtdswap_handle_badblock(d, eb);
982 return 0;
983 }
984
985 static int mtdswap_gc(struct mtdswap_dev *d, unsigned int background)
986 {
987 struct swap_eb *eb;
988 int ret;
989
990 if (d->spare_eblks < MIN_SPARE_EBLOCKS)
991 return 1;
992
993 eb = mtdswap_pick_gc_eblk(d, background);
994 if (!eb)
995 return 1;
996
997 ret = mtdswap_gc_eblock(d, eb);
998 if (ret == -ENOSPC)
999 return 1;
1000
1001 if (eb->flags & EBLOCK_FAILED) {
1002 mtdswap_handle_badblock(d, eb);
1003 return 0;
1004 }
1005
1006 eb->flags &= ~EBLOCK_BITFLIP;
1007 ret = mtdswap_erase_block(d, eb);
1008 if ((eb->flags & EBLOCK_READERR) &&
1009 (ret || !mtdswap_eblk_passes(d, eb)))
1010 return 0;
1011
1012 if (ret == 0)
1013 ret = mtdswap_write_marker(d, eb, MTDSWAP_TYPE_CLEAN);
1014
1015 if (ret == 0)
1016 mtdswap_rb_add(d, eb, MTDSWAP_CLEAN);
1017 else if (ret != -EIO && !mtd_is_eccerr(ret))
1018 mtdswap_rb_add(d, eb, MTDSWAP_DIRTY);
1019
1020 return 0;
1021 }
1022
1023 static void mtdswap_background(struct mtd_blktrans_dev *dev)
1024 {
1025 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1026 int ret;
1027
1028 while (1) {
1029 ret = mtdswap_gc(d, 1);
1030 if (ret || mtd_blktrans_cease_background(dev))
1031 return;
1032 }
1033 }
1034
1035 static void mtdswap_cleanup(struct mtdswap_dev *d)
1036 {
1037 vfree(d->eb_data);
1038 vfree(d->revmap);
1039 vfree(d->page_data);
1040 kfree(d->oob_buf);
1041 kfree(d->page_buf);
1042 }
1043
1044 static int mtdswap_flush(struct mtd_blktrans_dev *dev)
1045 {
1046 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1047
1048 mtd_sync(d->mtd);
1049 return 0;
1050 }
1051
1052 static unsigned int mtdswap_badblocks(struct mtd_info *mtd, uint64_t size)
1053 {
1054 loff_t offset;
1055 unsigned int badcnt;
1056
1057 badcnt = 0;
1058
1059 if (mtd_can_have_bb(mtd))
1060 for (offset = 0; offset < size; offset += mtd->erasesize)
1061 if (mtd_block_isbad(mtd, offset))
1062 badcnt++;
1063
1064 return badcnt;
1065 }
1066
1067 static int mtdswap_writesect(struct mtd_blktrans_dev *dev,
1068 unsigned long page, char *buf)
1069 {
1070 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1071 unsigned int newblock, mapped;
1072 struct swap_eb *eb;
1073 int ret;
1074
1075 d->sect_write_count++;
1076
1077 if (d->spare_eblks < MIN_SPARE_EBLOCKS)
1078 return -ENOSPC;
1079
1080 if (header) {
1081 /* Ignore writes to the header page */
1082 if (unlikely(page == 0))
1083 return 0;
1084
1085 page--;
1086 }
1087
1088 mapped = d->page_data[page];
1089 if (mapped <= BLOCK_MAX) {
1090 eb = d->eb_data + (mapped / d->pages_per_eblk);
1091 eb->active_count--;
1092 mtdswap_store_eb(d, eb);
1093 d->page_data[page] = BLOCK_UNDEF;
1094 d->revmap[mapped] = PAGE_UNDEF;
1095 }
1096
1097 ret = mtdswap_write_block(d, buf, page, &newblock, 0);
1098 d->mtd_write_count++;
1099
1100 if (ret < 0)
1101 return ret;
1102
1103 eb = d->eb_data + (newblock / d->pages_per_eblk);
1104 d->page_data[page] = newblock;
1105
1106 return 0;
1107 }
1108
1109 /* Provide a dummy swap header for the kernel */
1110 static int mtdswap_auto_header(struct mtdswap_dev *d, char *buf)
1111 {
1112 union swap_header *hd = (union swap_header *)(buf);
1113
1114 memset(buf, 0, PAGE_SIZE - 10);
1115
1116 hd->info.version = 1;
1117 hd->info.last_page = d->mbd_dev->size - 1;
1118 hd->info.nr_badpages = 0;
1119
1120 memcpy(buf + PAGE_SIZE - 10, "SWAPSPACE2", 10);
1121
1122 return 0;
1123 }
1124
1125 static int mtdswap_readsect(struct mtd_blktrans_dev *dev,
1126 unsigned long page, char *buf)
1127 {
1128 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1129 struct mtd_info *mtd = d->mtd;
1130 unsigned int realblock, retries;
1131 loff_t readpos;
1132 struct swap_eb *eb;
1133 size_t retlen;
1134 int ret;
1135
1136 d->sect_read_count++;
1137
1138 if (header) {
1139 if (unlikely(page == 0))
1140 return mtdswap_auto_header(d, buf);
1141
1142 page--;
1143 }
1144
1145 realblock = d->page_data[page];
1146 if (realblock > BLOCK_MAX) {
1147 memset(buf, 0x0, PAGE_SIZE);
1148 if (realblock == BLOCK_UNDEF)
1149 return 0;
1150 else
1151 return -EIO;
1152 }
1153
1154 eb = d->eb_data + (realblock / d->pages_per_eblk);
1155 BUG_ON(d->revmap[realblock] == PAGE_UNDEF);
1156
1157 readpos = (loff_t)realblock << PAGE_SHIFT;
1158 retries = 0;
1159
1160 retry:
1161 ret = mtd_read(mtd, readpos, PAGE_SIZE, &retlen, buf);
1162
1163 d->mtd_read_count++;
1164 if (mtd_is_bitflip(ret)) {
1165 eb->flags |= EBLOCK_BITFLIP;
1166 mtdswap_rb_add(d, eb, MTDSWAP_BITFLIP);
1167 ret = 0;
1168 }
1169
1170 if (ret < 0) {
1171 dev_err(d->dev, "Read error %d\n", ret);
1172 eb->flags |= EBLOCK_READERR;
1173 mtdswap_rb_add(d, eb, MTDSWAP_FAILING);
1174 retries++;
1175 if (retries < MTDSWAP_IO_RETRIES)
1176 goto retry;
1177
1178 return ret;
1179 }
1180
1181 if (retlen != PAGE_SIZE) {
1182 dev_err(d->dev, "Short read %zd\n", retlen);
1183 return -EIO;
1184 }
1185
1186 return 0;
1187 }
1188
1189 static int mtdswap_discard(struct mtd_blktrans_dev *dev, unsigned long first,
1190 unsigned nr_pages)
1191 {
1192 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1193 unsigned long page;
1194 struct swap_eb *eb;
1195 unsigned int mapped;
1196
1197 d->discard_count++;
1198
1199 for (page = first; page < first + nr_pages; page++) {
1200 mapped = d->page_data[page];
1201 if (mapped <= BLOCK_MAX) {
1202 eb = d->eb_data + (mapped / d->pages_per_eblk);
1203 eb->active_count--;
1204 mtdswap_store_eb(d, eb);
1205 d->page_data[page] = BLOCK_UNDEF;
1206 d->revmap[mapped] = PAGE_UNDEF;
1207 d->discard_page_count++;
1208 } else if (mapped == BLOCK_ERROR) {
1209 d->page_data[page] = BLOCK_UNDEF;
1210 d->discard_page_count++;
1211 }
1212 }
1213
1214 return 0;
1215 }
1216
1217 static int mtdswap_show(struct seq_file *s, void *data)
1218 {
1219 struct mtdswap_dev *d = (struct mtdswap_dev *) s->private;
1220 unsigned long sum;
1221 unsigned int count[MTDSWAP_TREE_CNT];
1222 unsigned int min[MTDSWAP_TREE_CNT];
1223 unsigned int max[MTDSWAP_TREE_CNT];
1224 unsigned int i, cw = 0, cwp = 0, cwecount = 0, bb_cnt, mapped, pages;
1225 uint64_t use_size;
1226 static const char * const name[] = {
1227 "clean", "used", "low", "high", "dirty", "bitflip", "failing"
1228 };
1229
1230 mutex_lock(&d->mbd_dev->lock);
1231
1232 for (i = 0; i < MTDSWAP_TREE_CNT; i++) {
1233 struct rb_root *root = &d->trees[i].root;
1234
1235 if (root->rb_node) {
1236 count[i] = d->trees[i].count;
1237 min[i] = MTDSWAP_ECNT_MIN(root);
1238 max[i] = MTDSWAP_ECNT_MAX(root);
1239 } else
1240 count[i] = 0;
1241 }
1242
1243 if (d->curr_write) {
1244 cw = 1;
1245 cwp = d->curr_write_pos;
1246 cwecount = d->curr_write->erase_count;
1247 }
1248
1249 sum = 0;
1250 for (i = 0; i < d->eblks; i++)
1251 sum += d->eb_data[i].erase_count;
1252
1253 use_size = (uint64_t)d->eblks * d->mtd->erasesize;
1254 bb_cnt = mtdswap_badblocks(d->mtd, use_size);
1255
1256 mapped = 0;
1257 pages = d->mbd_dev->size;
1258 for (i = 0; i < pages; i++)
1259 if (d->page_data[i] != BLOCK_UNDEF)
1260 mapped++;
1261
1262 mutex_unlock(&d->mbd_dev->lock);
1263
1264 for (i = 0; i < MTDSWAP_TREE_CNT; i++) {
1265 if (!count[i])
1266 continue;
1267
1268 if (min[i] != max[i])
1269 seq_printf(s, "%s:\t%5d erase blocks, erased min %d, "
1270 "max %d times\n",
1271 name[i], count[i], min[i], max[i]);
1272 else
1273 seq_printf(s, "%s:\t%5d erase blocks, all erased %d "
1274 "times\n", name[i], count[i], min[i]);
1275 }
1276
1277 if (bb_cnt)
1278 seq_printf(s, "bad:\t%5u erase blocks\n", bb_cnt);
1279
1280 if (cw)
1281 seq_printf(s, "current erase block: %u pages used, %u free, "
1282 "erased %u times\n",
1283 cwp, d->pages_per_eblk - cwp, cwecount);
1284
1285 seq_printf(s, "total erasures: %lu\n", sum);
1286
1287 seq_puts(s, "\n");
1288
1289 seq_printf(s, "mtdswap_readsect count: %llu\n", d->sect_read_count);
1290 seq_printf(s, "mtdswap_writesect count: %llu\n", d->sect_write_count);
1291 seq_printf(s, "mtdswap_discard count: %llu\n", d->discard_count);
1292 seq_printf(s, "mtd read count: %llu\n", d->mtd_read_count);
1293 seq_printf(s, "mtd write count: %llu\n", d->mtd_write_count);
1294 seq_printf(s, "discarded pages count: %llu\n", d->discard_page_count);
1295
1296 seq_puts(s, "\n");
1297 seq_printf(s, "total pages: %u\n", pages);
1298 seq_printf(s, "pages mapped: %u\n", mapped);
1299
1300 return 0;
1301 }
1302
1303 static int mtdswap_open(struct inode *inode, struct file *file)
1304 {
1305 return single_open(file, mtdswap_show, inode->i_private);
1306 }
1307
1308 static const struct file_operations mtdswap_fops = {
1309 .open = mtdswap_open,
1310 .read = seq_read,
1311 .llseek = seq_lseek,
1312 .release = single_release,
1313 };
1314
1315 static int mtdswap_add_debugfs(struct mtdswap_dev *d)
1316 {
1317 struct dentry *root = d->mtd->dbg.dfs_dir;
1318 struct dentry *dent;
1319
1320 if (!IS_ENABLED(CONFIG_DEBUG_FS))
1321 return 0;
1322
1323 if (IS_ERR_OR_NULL(root))
1324 return -1;
1325
1326 dent = debugfs_create_file("mtdswap_stats", S_IRUSR, root, d,
1327 &mtdswap_fops);
1328 if (!dent) {
1329 dev_err(d->dev, "debugfs_create_file failed\n");
1330 return -1;
1331 }
1332
1333 return 0;
1334 }
1335
1336 static int mtdswap_init(struct mtdswap_dev *d, unsigned int eblocks,
1337 unsigned int spare_cnt)
1338 {
1339 struct mtd_info *mtd = d->mbd_dev->mtd;
1340 unsigned int i, eblk_bytes, pages, blocks;
1341 int ret = -ENOMEM;
1342
1343 d->mtd = mtd;
1344 d->eblks = eblocks;
1345 d->spare_eblks = spare_cnt;
1346 d->pages_per_eblk = mtd->erasesize >> PAGE_SHIFT;
1347
1348 pages = d->mbd_dev->size;
1349 blocks = eblocks * d->pages_per_eblk;
1350
1351 for (i = 0; i < MTDSWAP_TREE_CNT; i++)
1352 d->trees[i].root = RB_ROOT;
1353
1354 d->page_data = vmalloc(sizeof(int)*pages);
1355 if (!d->page_data)
1356 goto page_data_fail;
1357
1358 d->revmap = vmalloc(sizeof(int)*blocks);
1359 if (!d->revmap)
1360 goto revmap_fail;
1361
1362 eblk_bytes = sizeof(struct swap_eb)*d->eblks;
1363 d->eb_data = vzalloc(eblk_bytes);
1364 if (!d->eb_data)
1365 goto eb_data_fail;
1366
1367 for (i = 0; i < pages; i++)
1368 d->page_data[i] = BLOCK_UNDEF;
1369
1370 for (i = 0; i < blocks; i++)
1371 d->revmap[i] = PAGE_UNDEF;
1372
1373 d->page_buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1374 if (!d->page_buf)
1375 goto page_buf_fail;
1376
1377 d->oob_buf = kmalloc(2 * mtd->oobavail, GFP_KERNEL);
1378 if (!d->oob_buf)
1379 goto oob_buf_fail;
1380
1381 mtdswap_scan_eblks(d);
1382
1383 return 0;
1384
1385 oob_buf_fail:
1386 kfree(d->page_buf);
1387 page_buf_fail:
1388 vfree(d->eb_data);
1389 eb_data_fail:
1390 vfree(d->revmap);
1391 revmap_fail:
1392 vfree(d->page_data);
1393 page_data_fail:
1394 printk(KERN_ERR "%s: init failed (%d)\n", MTDSWAP_PREFIX, ret);
1395 return ret;
1396 }
1397
1398 static void mtdswap_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
1399 {
1400 struct mtdswap_dev *d;
1401 struct mtd_blktrans_dev *mbd_dev;
1402 char *parts;
1403 char *this_opt;
1404 unsigned long part;
1405 unsigned int eblocks, eavailable, bad_blocks, spare_cnt;
1406 uint64_t swap_size, use_size, size_limit;
1407 int ret;
1408
1409 parts = &partitions[0];
1410 if (!*parts)
1411 return;
1412
1413 while ((this_opt = strsep(&parts, ",")) != NULL) {
1414 if (kstrtoul(this_opt, 0, &part) < 0)
1415 return;
1416
1417 if (mtd->index == part)
1418 break;
1419 }
1420
1421 if (mtd->index != part)
1422 return;
1423
1424 if (mtd->erasesize < PAGE_SIZE || mtd->erasesize % PAGE_SIZE) {
1425 printk(KERN_ERR "%s: Erase size %u not multiple of PAGE_SIZE "
1426 "%lu\n", MTDSWAP_PREFIX, mtd->erasesize, PAGE_SIZE);
1427 return;
1428 }
1429
1430 if (PAGE_SIZE % mtd->writesize || mtd->writesize > PAGE_SIZE) {
1431 printk(KERN_ERR "%s: PAGE_SIZE %lu not multiple of write size"
1432 " %u\n", MTDSWAP_PREFIX, PAGE_SIZE, mtd->writesize);
1433 return;
1434 }
1435
1436 if (!mtd->oobsize || mtd->oobavail < MTDSWAP_OOBSIZE) {
1437 printk(KERN_ERR "%s: Not enough free bytes in OOB, "
1438 "%d available, %zu needed.\n",
1439 MTDSWAP_PREFIX, mtd->oobavail, MTDSWAP_OOBSIZE);
1440 return;
1441 }
1442
1443 if (spare_eblocks > 100)
1444 spare_eblocks = 100;
1445
1446 use_size = mtd->size;
1447 size_limit = (uint64_t) BLOCK_MAX * PAGE_SIZE;
1448
1449 if (mtd->size > size_limit) {
1450 printk(KERN_WARNING "%s: Device too large. Limiting size to "
1451 "%llu bytes\n", MTDSWAP_PREFIX, size_limit);
1452 use_size = size_limit;
1453 }
1454
1455 eblocks = mtd_div_by_eb(use_size, mtd);
1456 use_size = (uint64_t)eblocks * mtd->erasesize;
1457 bad_blocks = mtdswap_badblocks(mtd, use_size);
1458 eavailable = eblocks - bad_blocks;
1459
1460 if (eavailable < MIN_ERASE_BLOCKS) {
1461 printk(KERN_ERR "%s: Not enough erase blocks. %u available, "
1462 "%d needed\n", MTDSWAP_PREFIX, eavailable,
1463 MIN_ERASE_BLOCKS);
1464 return;
1465 }
1466
1467 spare_cnt = div_u64((uint64_t)eavailable * spare_eblocks, 100);
1468
1469 if (spare_cnt < MIN_SPARE_EBLOCKS)
1470 spare_cnt = MIN_SPARE_EBLOCKS;
1471
1472 if (spare_cnt > eavailable - 1)
1473 spare_cnt = eavailable - 1;
1474
1475 swap_size = (uint64_t)(eavailable - spare_cnt) * mtd->erasesize +
1476 (header ? PAGE_SIZE : 0);
1477
1478 printk(KERN_INFO "%s: Enabling MTD swap on device %lu, size %llu KB, "
1479 "%u spare, %u bad blocks\n",
1480 MTDSWAP_PREFIX, part, swap_size / 1024, spare_cnt, bad_blocks);
1481
1482 d = kzalloc(sizeof(struct mtdswap_dev), GFP_KERNEL);
1483 if (!d)
1484 return;
1485
1486 mbd_dev = kzalloc(sizeof(struct mtd_blktrans_dev), GFP_KERNEL);
1487 if (!mbd_dev) {
1488 kfree(d);
1489 return;
1490 }
1491
1492 d->mbd_dev = mbd_dev;
1493 mbd_dev->priv = d;
1494
1495 mbd_dev->mtd = mtd;
1496 mbd_dev->devnum = mtd->index;
1497 mbd_dev->size = swap_size >> PAGE_SHIFT;
1498 mbd_dev->tr = tr;
1499
1500 if (!(mtd->flags & MTD_WRITEABLE))
1501 mbd_dev->readonly = 1;
1502
1503 if (mtdswap_init(d, eblocks, spare_cnt) < 0)
1504 goto init_failed;
1505
1506 if (add_mtd_blktrans_dev(mbd_dev) < 0)
1507 goto cleanup;
1508
1509 d->dev = disk_to_dev(mbd_dev->disk);
1510
1511 ret = mtdswap_add_debugfs(d);
1512 if (ret < 0)
1513 goto debugfs_failed;
1514
1515 return;
1516
1517 debugfs_failed:
1518 del_mtd_blktrans_dev(mbd_dev);
1519
1520 cleanup:
1521 mtdswap_cleanup(d);
1522
1523 init_failed:
1524 kfree(mbd_dev);
1525 kfree(d);
1526 }
1527
1528 static void mtdswap_remove_dev(struct mtd_blktrans_dev *dev)
1529 {
1530 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1531
1532 del_mtd_blktrans_dev(dev);
1533 mtdswap_cleanup(d);
1534 kfree(d);
1535 }
1536
1537 static struct mtd_blktrans_ops mtdswap_ops = {
1538 .name = "mtdswap",
1539 .major = 0,
1540 .part_bits = 0,
1541 .blksize = PAGE_SIZE,
1542 .flush = mtdswap_flush,
1543 .readsect = mtdswap_readsect,
1544 .writesect = mtdswap_writesect,
1545 .discard = mtdswap_discard,
1546 .background = mtdswap_background,
1547 .add_mtd = mtdswap_add_mtd,
1548 .remove_dev = mtdswap_remove_dev,
1549 .owner = THIS_MODULE,
1550 };
1551
1552 static int __init mtdswap_modinit(void)
1553 {
1554 return register_mtd_blktrans(&mtdswap_ops);
1555 }
1556
1557 static void __exit mtdswap_modexit(void)
1558 {
1559 deregister_mtd_blktrans(&mtdswap_ops);
1560 }
1561
1562 module_init(mtdswap_modinit);
1563 module_exit(mtdswap_modexit);
1564
1565
1566 MODULE_LICENSE("GPL");
1567 MODULE_AUTHOR("Jarkko Lavinen <jarkko.lavinen@nokia.com>");
1568 MODULE_DESCRIPTION("Block device access to an MTD suitable for using as "
1569 "swap space");
CRIS linux kernel tree