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The discovered bit in PGCCSR register indicates if the device has been
[linux-2.6/next.git] / drivers / mtd / mtdswap.c
blob9961063b90a262b7080be6a925c1b62cb3146b0c
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_TRESHOLD 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 struct dentry *debugfs_root;
143 };
144
145 struct mtdswap_oobdata {
146 __le16 magic;
147 __le32 count;
148 } __attribute__((packed));
149
150 #define MTDSWAP_MAGIC_CLEAN 0x2095
151 #define MTDSWAP_MAGIC_DIRTY (MTDSWAP_MAGIC_CLEAN + 1)
152 #define MTDSWAP_TYPE_CLEAN 0
153 #define MTDSWAP_TYPE_DIRTY 1
154 #define MTDSWAP_OOBSIZE sizeof(struct mtdswap_oobdata)
155
156 #define MTDSWAP_ERASE_RETRIES 3 /* Before marking erase block bad */
157 #define MTDSWAP_IO_RETRIES 3
158
159 enum {
160 MTDSWAP_SCANNED_CLEAN,
161 MTDSWAP_SCANNED_DIRTY,
162 MTDSWAP_SCANNED_BITFLIP,
163 MTDSWAP_SCANNED_BAD,
164 };
165
166 /*
167 * In the worst case mtdswap_writesect() has allocated the last clean
168 * page from the current block and is then pre-empted by the GC
169 * thread. The thread can consume a full erase block when moving a
170 * block.
171 */
172 #define MIN_SPARE_EBLOCKS 2
173 #define MIN_ERASE_BLOCKS (MIN_SPARE_EBLOCKS + 1)
174
175 #define TREE_ROOT(d, name) (&d->trees[MTDSWAP_ ## name].root)
176 #define TREE_EMPTY(d, name) (TREE_ROOT(d, name)->rb_node == NULL)
177 #define TREE_NONEMPTY(d, name) (!TREE_EMPTY(d, name))
178 #define TREE_COUNT(d, name) (d->trees[MTDSWAP_ ## name].count)
179
180 #define MTDSWAP_MBD_TO_MTDSWAP(dev) ((struct mtdswap_dev *)dev->priv)
181
182 static char partitions[128] = "";
183 module_param_string(partitions, partitions, sizeof(partitions), 0444);
184 MODULE_PARM_DESC(partitions, "MTD partition numbers to use as swap "
185 "partitions=\"1,3,5\"");
186
187 static unsigned int spare_eblocks = 10;
188 module_param(spare_eblocks, uint, 0444);
189 MODULE_PARM_DESC(spare_eblocks, "Percentage of spare erase blocks for "
190 "garbage collection (default 10%)");
191
192 static bool header; /* false */
193 module_param(header, bool, 0444);
194 MODULE_PARM_DESC(header,
195 "Include builtin swap header (default 0, without header)");
196
197 static int mtdswap_gc(struct mtdswap_dev *d, unsigned int background);
198
199 static loff_t mtdswap_eb_offset(struct mtdswap_dev *d, struct swap_eb *eb)
200 {
201 return (loff_t)(eb - d->eb_data) * d->mtd->erasesize;
202 }
203
204 static void mtdswap_eb_detach(struct mtdswap_dev *d, struct swap_eb *eb)
205 {
206 unsigned int oldidx;
207 struct mtdswap_tree *tp;
208
209 if (eb->root) {
210 tp = container_of(eb->root, struct mtdswap_tree, root);
211 oldidx = tp - &d->trees[0];
212
213 d->trees[oldidx].count--;
214 rb_erase(&eb->rb, eb->root);
215 }
216 }
217
218 static void __mtdswap_rb_add(struct rb_root *root, struct swap_eb *eb)
219 {
220 struct rb_node **p, *parent = NULL;
221 struct swap_eb *cur;
222
223 p = &root->rb_node;
224 while (*p) {
225 parent = *p;
226 cur = rb_entry(parent, struct swap_eb, rb);
227 if (eb->erase_count > cur->erase_count)
228 p = &(*p)->rb_right;
229 else
230 p = &(*p)->rb_left;
231 }
232
233 rb_link_node(&eb->rb, parent, p);
234 rb_insert_color(&eb->rb, root);
235 }
236
237 static void mtdswap_rb_add(struct mtdswap_dev *d, struct swap_eb *eb, int idx)
238 {
239 struct rb_root *root;
240
241 if (eb->root == &d->trees[idx].root)
242 return;
243
244 mtdswap_eb_detach(d, eb);
245 root = &d->trees[idx].root;
246 __mtdswap_rb_add(root, eb);
247 eb->root = root;
248 d->trees[idx].count++;
249 }
250
251 static struct rb_node *mtdswap_rb_index(struct rb_root *root, unsigned int idx)
252 {
253 struct rb_node *p;
254 unsigned int i;
255
256 p = rb_first(root);
257 i = 0;
258 while (i < idx && p) {
259 p = rb_next(p);
260 i++;
261 }
262
263 return p;
264 }
265
266 static int mtdswap_handle_badblock(struct mtdswap_dev *d, struct swap_eb *eb)
267 {
268 int ret;
269 loff_t offset;
270
271 d->spare_eblks--;
272 eb->flags |= EBLOCK_BAD;
273 mtdswap_eb_detach(d, eb);
274 eb->root = NULL;
275
276 /* badblocks not supported */
277 if (!d->mtd->block_markbad)
278 return 1;
279
280 offset = mtdswap_eb_offset(d, eb);
281 dev_warn(d->dev, "Marking bad block at %08llx\n", offset);
282 ret = d->mtd->block_markbad(d->mtd, offset);
283
284 if (ret) {
285 dev_warn(d->dev, "Mark block bad failed for block at %08llx "
286 "error %d\n", offset, ret);
287 return ret;
288 }
289
290 return 1;
291
292 }
293
294 static int mtdswap_handle_write_error(struct mtdswap_dev *d, struct swap_eb *eb)
295 {
296 unsigned int marked = eb->flags & EBLOCK_FAILED;
297 struct swap_eb *curr_write = d->curr_write;
298
299 eb->flags |= EBLOCK_FAILED;
300 if (curr_write == eb) {
301 d->curr_write = NULL;
302
303 if (!marked && d->curr_write_pos != 0) {
304 mtdswap_rb_add(d, eb, MTDSWAP_FAILING);
305 return 0;
306 }
307 }
308
309 return mtdswap_handle_badblock(d, eb);
310 }
311
312 static int mtdswap_read_oob(struct mtdswap_dev *d, loff_t from,
313 struct mtd_oob_ops *ops)
314 {
315 int ret = d->mtd->read_oob(d->mtd, from, ops);
316
317 if (ret == -EUCLEAN)
318 return ret;
319
320 if (ret) {
321 dev_warn(d->dev, "Read OOB failed %d for block at %08llx\n",
322 ret, from);
323 return ret;
324 }
325
326 if (ops->oobretlen < ops->ooblen) {
327 dev_warn(d->dev, "Read OOB return short read (%zd bytes not "
328 "%zd) for block at %08llx\n",
329 ops->oobretlen, ops->ooblen, from);
330 return -EIO;
331 }
332
333 return 0;
334 }
335
336 static int mtdswap_read_markers(struct mtdswap_dev *d, struct swap_eb *eb)
337 {
338 struct mtdswap_oobdata *data, *data2;
339 int ret;
340 loff_t offset;
341 struct mtd_oob_ops ops;
342
343 offset = mtdswap_eb_offset(d, eb);
344
345 /* Check first if the block is bad. */
346 if (d->mtd->block_isbad && d->mtd->block_isbad(d->mtd, offset))
347 return MTDSWAP_SCANNED_BAD;
348
349 ops.ooblen = 2 * d->mtd->ecclayout->oobavail;
350 ops.oobbuf = d->oob_buf;
351 ops.ooboffs = 0;
352 ops.datbuf = NULL;
353 ops.mode = MTD_OOB_AUTO;
354
355 ret = mtdswap_read_oob(d, offset, &ops);
356
357 if (ret && ret != -EUCLEAN)
358 return ret;
359
360 data = (struct mtdswap_oobdata *)d->oob_buf;
361 data2 = (struct mtdswap_oobdata *)
362 (d->oob_buf + d->mtd->ecclayout->oobavail);
363
364 if (le16_to_cpu(data->magic) == MTDSWAP_MAGIC_CLEAN) {
365 eb->erase_count = le32_to_cpu(data->count);
366 if (ret == -EUCLEAN)
367 ret = MTDSWAP_SCANNED_BITFLIP;
368 else {
369 if (le16_to_cpu(data2->magic) == MTDSWAP_MAGIC_DIRTY)
370 ret = MTDSWAP_SCANNED_DIRTY;
371 else
372 ret = MTDSWAP_SCANNED_CLEAN;
373 }
374 } else {
375 eb->flags |= EBLOCK_NOMAGIC;
376 ret = MTDSWAP_SCANNED_DIRTY;
377 }
378
379 return ret;
380 }
381
382 static int mtdswap_write_marker(struct mtdswap_dev *d, struct swap_eb *eb,
383 u16 marker)
384 {
385 struct mtdswap_oobdata n;
386 int ret;
387 loff_t offset;
388 struct mtd_oob_ops ops;
389
390 ops.ooboffs = 0;
391 ops.oobbuf = (uint8_t *)&n;
392 ops.mode = MTD_OOB_AUTO;
393 ops.datbuf = NULL;
394
395 if (marker == MTDSWAP_TYPE_CLEAN) {
396 n.magic = cpu_to_le16(MTDSWAP_MAGIC_CLEAN);
397 n.count = cpu_to_le32(eb->erase_count);
398 ops.ooblen = MTDSWAP_OOBSIZE;
399 offset = mtdswap_eb_offset(d, eb);
400 } else {
401 n.magic = cpu_to_le16(MTDSWAP_MAGIC_DIRTY);
402 ops.ooblen = sizeof(n.magic);
403 offset = mtdswap_eb_offset(d, eb) + d->mtd->writesize;
404 }
405
406 ret = d->mtd->write_oob(d->mtd, offset , &ops);
407
408 if (ret) {
409 dev_warn(d->dev, "Write OOB failed for block at %08llx "
410 "error %d\n", offset, ret);
411 if (ret == -EIO || ret == -EBADMSG)
412 mtdswap_handle_write_error(d, eb);
413 return ret;
414 }
415
416 if (ops.oobretlen != ops.ooblen) {
417 dev_warn(d->dev, "Short OOB write for block at %08llx: "
418 "%zd not %zd\n",
419 offset, ops.oobretlen, ops.ooblen);
420 return ret;
421 }
422
423 return 0;
424 }
425
426 /*
427 * Are there any erase blocks without MAGIC_CLEAN header, presumably
428 * because power was cut off after erase but before header write? We
429 * need to guestimate the erase count.
430 */
431 static void mtdswap_check_counts(struct mtdswap_dev *d)
432 {
433 struct rb_root hist_root = RB_ROOT;
434 struct rb_node *medrb;
435 struct swap_eb *eb;
436 unsigned int i, cnt, median;
437
438 cnt = 0;
439 for (i = 0; i < d->eblks; i++) {
440 eb = d->eb_data + i;
441
442 if (eb->flags & (EBLOCK_NOMAGIC | EBLOCK_BAD | EBLOCK_READERR))
443 continue;
444
445 __mtdswap_rb_add(&hist_root, eb);
446 cnt++;
447 }
448
449 if (cnt == 0)
450 return;
451
452 medrb = mtdswap_rb_index(&hist_root, cnt / 2);
453 median = rb_entry(medrb, struct swap_eb, rb)->erase_count;
454
455 d->max_erase_count = MTDSWAP_ECNT_MAX(&hist_root);
456
457 for (i = 0; i < d->eblks; i++) {
458 eb = d->eb_data + i;
459
460 if (eb->flags & (EBLOCK_NOMAGIC | EBLOCK_READERR))
461 eb->erase_count = median;
462
463 if (eb->flags & (EBLOCK_NOMAGIC | EBLOCK_BAD | EBLOCK_READERR))
464 continue;
465
466 rb_erase(&eb->rb, &hist_root);
467 }
468 }
469
470 static void mtdswap_scan_eblks(struct mtdswap_dev *d)
471 {
472 int status;
473 unsigned int i, idx;
474 struct swap_eb *eb;
475
476 for (i = 0; i < d->eblks; i++) {
477 eb = d->eb_data + i;
478
479 status = mtdswap_read_markers(d, eb);
480 if (status < 0)
481 eb->flags |= EBLOCK_READERR;
482 else if (status == MTDSWAP_SCANNED_BAD) {
483 eb->flags |= EBLOCK_BAD;
484 continue;
485 }
486
487 switch (status) {
488 case MTDSWAP_SCANNED_CLEAN:
489 idx = MTDSWAP_CLEAN;
490 break;
491 case MTDSWAP_SCANNED_DIRTY:
492 case MTDSWAP_SCANNED_BITFLIP:
493 idx = MTDSWAP_DIRTY;
494 break;
495 default:
496 idx = MTDSWAP_FAILING;
497 }
498
499 eb->flags |= (idx << EBLOCK_IDX_SHIFT);
500 }
501
502 mtdswap_check_counts(d);
503
504 for (i = 0; i < d->eblks; i++) {
505 eb = d->eb_data + i;
506
507 if (eb->flags & EBLOCK_BAD)
508 continue;
509
510 idx = eb->flags >> EBLOCK_IDX_SHIFT;
511 mtdswap_rb_add(d, eb, idx);
512 }
513 }
514
515 /*
516 * Place eblk into a tree corresponding to its number of active blocks
517 * it contains.
518 */
519 static void mtdswap_store_eb(struct mtdswap_dev *d, struct swap_eb *eb)
520 {
521 unsigned int weight = eb->active_count;
522 unsigned int maxweight = d->pages_per_eblk;
523
524 if (eb == d->curr_write)
525 return;
526
527 if (eb->flags & EBLOCK_BITFLIP)
528 mtdswap_rb_add(d, eb, MTDSWAP_BITFLIP);
529 else if (eb->flags & (EBLOCK_READERR | EBLOCK_FAILED))
530 mtdswap_rb_add(d, eb, MTDSWAP_FAILING);
531 if (weight == maxweight)
532 mtdswap_rb_add(d, eb, MTDSWAP_USED);
533 else if (weight == 0)
534 mtdswap_rb_add(d, eb, MTDSWAP_DIRTY);
535 else if (weight > (maxweight/2))
536 mtdswap_rb_add(d, eb, MTDSWAP_LOWFRAG);
537 else
538 mtdswap_rb_add(d, eb, MTDSWAP_HIFRAG);
539 }
540
541
542 static void mtdswap_erase_callback(struct erase_info *done)
543 {
544 wait_queue_head_t *wait_q = (wait_queue_head_t *)done->priv;
545 wake_up(wait_q);
546 }
547
548 static int mtdswap_erase_block(struct mtdswap_dev *d, struct swap_eb *eb)
549 {
550 struct mtd_info *mtd = d->mtd;
551 struct erase_info erase;
552 wait_queue_head_t wq;
553 unsigned int retries = 0;
554 int ret;
555
556 eb->erase_count++;
557 if (eb->erase_count > d->max_erase_count)
558 d->max_erase_count = eb->erase_count;
559
560 retry:
561 init_waitqueue_head(&wq);
562 memset(&erase, 0, sizeof(struct erase_info));
563
564 erase.mtd = mtd;
565 erase.callback = mtdswap_erase_callback;
566 erase.addr = mtdswap_eb_offset(d, eb);
567 erase.len = mtd->erasesize;
568 erase.priv = (u_long)&wq;
569
570 ret = mtd->erase(mtd, &erase);
571 if (ret) {
572 if (retries++ < MTDSWAP_ERASE_RETRIES) {
573 dev_warn(d->dev,
574 "erase of erase block %#llx on %s failed",
575 erase.addr, mtd->name);
576 yield();
577 goto retry;
578 }
579
580 dev_err(d->dev, "Cannot erase erase block %#llx on %s\n",
581 erase.addr, mtd->name);
582
583 mtdswap_handle_badblock(d, eb);
584 return -EIO;
585 }
586
587 ret = wait_event_interruptible(wq, erase.state == MTD_ERASE_DONE ||
588 erase.state == MTD_ERASE_FAILED);
589 if (ret) {
590 dev_err(d->dev, "Interrupted erase block %#llx erassure on %s",
591 erase.addr, mtd->name);
592 return -EINTR;
593 }
594
595 if (erase.state == MTD_ERASE_FAILED) {
596 if (retries++ < MTDSWAP_ERASE_RETRIES) {
597 dev_warn(d->dev,
598 "erase of erase block %#llx on %s failed",
599 erase.addr, mtd->name);
600 yield();
601 goto retry;
602 }
603
604 mtdswap_handle_badblock(d, eb);
605 return -EIO;
606 }
607
608 return 0;
609 }
610
611 static int mtdswap_map_free_block(struct mtdswap_dev *d, unsigned int page,
612 unsigned int *block)
613 {
614 int ret;
615 struct swap_eb *old_eb = d->curr_write;
616 struct rb_root *clean_root;
617 struct swap_eb *eb;
618
619 if (old_eb == NULL || d->curr_write_pos >= d->pages_per_eblk) {
620 do {
621 if (TREE_EMPTY(d, CLEAN))
622 return -ENOSPC;
623
624 clean_root = TREE_ROOT(d, CLEAN);
625 eb = rb_entry(rb_first(clean_root), struct swap_eb, rb);
626 rb_erase(&eb->rb, clean_root);
627 eb->root = NULL;
628 TREE_COUNT(d, CLEAN)--;
629
630 ret = mtdswap_write_marker(d, eb, MTDSWAP_TYPE_DIRTY);
631 } while (ret == -EIO || ret == -EBADMSG);
632
633 if (ret)
634 return ret;
635
636 d->curr_write_pos = 0;
637 d->curr_write = eb;
638 if (old_eb)
639 mtdswap_store_eb(d, old_eb);
640 }
641
642 *block = (d->curr_write - d->eb_data) * d->pages_per_eblk +
643 d->curr_write_pos;
644
645 d->curr_write->active_count++;
646 d->revmap[*block] = page;
647 d->curr_write_pos++;
648
649 return 0;
650 }
651
652 static unsigned int mtdswap_free_page_cnt(struct mtdswap_dev *d)
653 {
654 return TREE_COUNT(d, CLEAN) * d->pages_per_eblk +
655 d->pages_per_eblk - d->curr_write_pos;
656 }
657
658 static unsigned int mtdswap_enough_free_pages(struct mtdswap_dev *d)
659 {
660 return mtdswap_free_page_cnt(d) > d->pages_per_eblk;
661 }
662
663 static int mtdswap_write_block(struct mtdswap_dev *d, char *buf,
664 unsigned int page, unsigned int *bp, int gc_context)
665 {
666 struct mtd_info *mtd = d->mtd;
667 struct swap_eb *eb;
668 size_t retlen;
669 loff_t writepos;
670 int ret;
671
672 retry:
673 if (!gc_context)
674 while (!mtdswap_enough_free_pages(d))
675 if (mtdswap_gc(d, 0) > 0)
676 return -ENOSPC;
677
678 ret = mtdswap_map_free_block(d, page, bp);
679 eb = d->eb_data + (*bp / d->pages_per_eblk);
680
681 if (ret == -EIO || ret == -EBADMSG) {
682 d->curr_write = NULL;
683 eb->active_count--;
684 d->revmap[*bp] = PAGE_UNDEF;
685 goto retry;
686 }
687
688 if (ret < 0)
689 return ret;
690
691 writepos = (loff_t)*bp << PAGE_SHIFT;
692 ret = mtd->write(mtd, writepos, PAGE_SIZE, &retlen, buf);
693 if (ret == -EIO || ret == -EBADMSG) {
694 d->curr_write_pos--;
695 eb->active_count--;
696 d->revmap[*bp] = PAGE_UNDEF;
697 mtdswap_handle_write_error(d, eb);
698 goto retry;
699 }
700
701 if (ret < 0) {
702 dev_err(d->dev, "Write to MTD device failed: %d (%zd written)",
703 ret, retlen);
704 goto err;
705 }
706
707 if (retlen != PAGE_SIZE) {
708 dev_err(d->dev, "Short write to MTD device: %zd written",
709 retlen);
710 ret = -EIO;
711 goto err;
712 }
713
714 return ret;
715
716 err:
717 d->curr_write_pos--;
718 eb->active_count--;
719 d->revmap[*bp] = PAGE_UNDEF;
720
721 return ret;
722 }
723
724 static int mtdswap_move_block(struct mtdswap_dev *d, unsigned int oldblock,
725 unsigned int *newblock)
726 {
727 struct mtd_info *mtd = d->mtd;
728 struct swap_eb *eb, *oldeb;
729 int ret;
730 size_t retlen;
731 unsigned int page, retries;
732 loff_t readpos;
733
734 page = d->revmap[oldblock];
735 readpos = (loff_t) oldblock << PAGE_SHIFT;
736 retries = 0;
737
738 retry:
739 ret = mtd->read(mtd, readpos, PAGE_SIZE, &retlen, d->page_buf);
740
741 if (ret < 0 && ret != -EUCLEAN) {
742 oldeb = d->eb_data + oldblock / d->pages_per_eblk;
743 oldeb->flags |= EBLOCK_READERR;
744
745 dev_err(d->dev, "Read Error: %d (block %u)\n", ret,
746 oldblock);
747 retries++;
748 if (retries < MTDSWAP_IO_RETRIES)
749 goto retry;
750
751 goto read_error;
752 }
753
754 if (retlen != PAGE_SIZE) {
755 dev_err(d->dev, "Short read: %zd (block %u)\n", retlen,
756 oldblock);
757 ret = -EIO;
758 goto read_error;
759 }
760
761 ret = mtdswap_write_block(d, d->page_buf, page, newblock, 1);
762 if (ret < 0) {
763 d->page_data[page] = BLOCK_ERROR;
764 dev_err(d->dev, "Write error: %d\n", ret);
765 return ret;
766 }
767
768 eb = d->eb_data + *newblock / d->pages_per_eblk;
769 d->page_data[page] = *newblock;
770 d->revmap[oldblock] = PAGE_UNDEF;
771 eb = d->eb_data + oldblock / d->pages_per_eblk;
772 eb->active_count--;
773
774 return 0;
775
776 read_error:
777 d->page_data[page] = BLOCK_ERROR;
778 d->revmap[oldblock] = PAGE_UNDEF;
779 return ret;
780 }
781
782 static int mtdswap_gc_eblock(struct mtdswap_dev *d, struct swap_eb *eb)
783 {
784 unsigned int i, block, eblk_base, newblock;
785 int ret, errcode;
786
787 errcode = 0;
788 eblk_base = (eb - d->eb_data) * d->pages_per_eblk;
789
790 for (i = 0; i < d->pages_per_eblk; i++) {
791 if (d->spare_eblks < MIN_SPARE_EBLOCKS)
792 return -ENOSPC;
793
794 block = eblk_base + i;
795 if (d->revmap[block] == PAGE_UNDEF)
796 continue;
797
798 ret = mtdswap_move_block(d, block, &newblock);
799 if (ret < 0 && !errcode)
800 errcode = ret;
801 }
802
803 return errcode;
804 }
805
806 static int __mtdswap_choose_gc_tree(struct mtdswap_dev *d)
807 {
808 int idx, stopat;
809
810 if (TREE_COUNT(d, CLEAN) < LOW_FRAG_GC_TRESHOLD)
811 stopat = MTDSWAP_LOWFRAG;
812 else
813 stopat = MTDSWAP_HIFRAG;
814
815 for (idx = MTDSWAP_BITFLIP; idx >= stopat; idx--)
816 if (d->trees[idx].root.rb_node != NULL)
817 return idx;
818
819 return -1;
820 }
821
822 static int mtdswap_wlfreq(unsigned int maxdiff)
823 {
824 unsigned int h, x, y, dist, base;
825
826 /*
827 * Calculate linear ramp down from f1 to f2 when maxdiff goes from
828 * MAX_ERASE_DIFF to MAX_ERASE_DIFF + COLLECT_NONDIRTY_BASE. Similar
829 * to triangle with height f1 - f1 and width COLLECT_NONDIRTY_BASE.
830 */
831
832 dist = maxdiff - MAX_ERASE_DIFF;
833 if (dist > COLLECT_NONDIRTY_BASE)
834 dist = COLLECT_NONDIRTY_BASE;
835
836 /*
837 * Modelling the slop as right angular triangle with base
838 * COLLECT_NONDIRTY_BASE and height freq1 - freq2. The ratio y/x is
839 * equal to the ratio h/base.
840 */
841 h = COLLECT_NONDIRTY_FREQ1 - COLLECT_NONDIRTY_FREQ2;
842 base = COLLECT_NONDIRTY_BASE;
843
844 x = dist - base;
845 y = (x * h + base / 2) / base;
846
847 return COLLECT_NONDIRTY_FREQ2 + y;
848 }
849
850 static int mtdswap_choose_wl_tree(struct mtdswap_dev *d)
851 {
852 static unsigned int pick_cnt;
853 unsigned int i, idx = -1, wear, max;
854 struct rb_root *root;
855
856 max = 0;
857 for (i = 0; i <= MTDSWAP_DIRTY; i++) {
858 root = &d->trees[i].root;
859 if (root->rb_node == NULL)
860 continue;
861
862 wear = d->max_erase_count - MTDSWAP_ECNT_MIN(root);
863 if (wear > max) {
864 max = wear;
865 idx = i;
866 }
867 }
868
869 if (max > MAX_ERASE_DIFF && pick_cnt >= mtdswap_wlfreq(max) - 1) {
870 pick_cnt = 0;
871 return idx;
872 }
873
874 pick_cnt++;
875 return -1;
876 }
877
878 static int mtdswap_choose_gc_tree(struct mtdswap_dev *d,
879 unsigned int background)
880 {
881 int idx;
882
883 if (TREE_NONEMPTY(d, FAILING) &&
884 (background || (TREE_EMPTY(d, CLEAN) && TREE_EMPTY(d, DIRTY))))
885 return MTDSWAP_FAILING;
886
887 idx = mtdswap_choose_wl_tree(d);
888 if (idx >= MTDSWAP_CLEAN)
889 return idx;
890
891 return __mtdswap_choose_gc_tree(d);
892 }
893
894 static struct swap_eb *mtdswap_pick_gc_eblk(struct mtdswap_dev *d,
895 unsigned int background)
896 {
897 struct rb_root *rp = NULL;
898 struct swap_eb *eb = NULL;
899 int idx;
900
901 if (background && TREE_COUNT(d, CLEAN) > CLEAN_BLOCK_THRESHOLD &&
902 TREE_EMPTY(d, DIRTY) && TREE_EMPTY(d, FAILING))
903 return NULL;
904
905 idx = mtdswap_choose_gc_tree(d, background);
906 if (idx < 0)
907 return NULL;
908
909 rp = &d->trees[idx].root;
910 eb = rb_entry(rb_first(rp), struct swap_eb, rb);
911
912 rb_erase(&eb->rb, rp);
913 eb->root = NULL;
914 d->trees[idx].count--;
915 return eb;
916 }
917
918 static unsigned int mtdswap_test_patt(unsigned int i)
919 {
920 return i % 2 ? 0x55555555 : 0xAAAAAAAA;
921 }
922
923 static unsigned int mtdswap_eblk_passes(struct mtdswap_dev *d,
924 struct swap_eb *eb)
925 {
926 struct mtd_info *mtd = d->mtd;
927 unsigned int test, i, j, patt, mtd_pages;
928 loff_t base, pos;
929 unsigned int *p1 = (unsigned int *)d->page_buf;
930 unsigned char *p2 = (unsigned char *)d->oob_buf;
931 struct mtd_oob_ops ops;
932 int ret;
933
934 ops.mode = MTD_OOB_AUTO;
935 ops.len = mtd->writesize;
936 ops.ooblen = mtd->ecclayout->oobavail;
937 ops.ooboffs = 0;
938 ops.datbuf = d->page_buf;
939 ops.oobbuf = d->oob_buf;
940 base = mtdswap_eb_offset(d, eb);
941 mtd_pages = d->pages_per_eblk * PAGE_SIZE / mtd->writesize;
942
943 for (test = 0; test < 2; test++) {
944 pos = base;
945 for (i = 0; i < mtd_pages; i++) {
946 patt = mtdswap_test_patt(test + i);
947 memset(d->page_buf, patt, mtd->writesize);
948 memset(d->oob_buf, patt, mtd->ecclayout->oobavail);
949 ret = mtd->write_oob(mtd, pos, &ops);
950 if (ret)
951 goto error;
952
953 pos += mtd->writesize;
954 }
955
956 pos = base;
957 for (i = 0; i < mtd_pages; i++) {
958 ret = mtd->read_oob(mtd, pos, &ops);
959 if (ret)
960 goto error;
961
962 patt = mtdswap_test_patt(test + i);
963 for (j = 0; j < mtd->writesize/sizeof(int); j++)
964 if (p1[j] != patt)
965 goto error;
966
967 for (j = 0; j < mtd->ecclayout->oobavail; j++)
968 if (p2[j] != (unsigned char)patt)
969 goto error;
970
971 pos += mtd->writesize;
972 }
973
974 ret = mtdswap_erase_block(d, eb);
975 if (ret)
976 goto error;
977 }
978
979 eb->flags &= ~EBLOCK_READERR;
980 return 1;
981
982 error:
983 mtdswap_handle_badblock(d, eb);
984 return 0;
985 }
986
987 static int mtdswap_gc(struct mtdswap_dev *d, unsigned int background)
988 {
989 struct swap_eb *eb;
990 int ret;
991
992 if (d->spare_eblks < MIN_SPARE_EBLOCKS)
993 return 1;
994
995 eb = mtdswap_pick_gc_eblk(d, background);
996 if (!eb)
997 return 1;
998
999 ret = mtdswap_gc_eblock(d, eb);
1000 if (ret == -ENOSPC)
1001 return 1;
1002
1003 if (eb->flags & EBLOCK_FAILED) {
1004 mtdswap_handle_badblock(d, eb);
1005 return 0;
1006 }
1007
1008 eb->flags &= ~EBLOCK_BITFLIP;
1009 ret = mtdswap_erase_block(d, eb);
1010 if ((eb->flags & EBLOCK_READERR) &&
1011 (ret || !mtdswap_eblk_passes(d, eb)))
1012 return 0;
1013
1014 if (ret == 0)
1015 ret = mtdswap_write_marker(d, eb, MTDSWAP_TYPE_CLEAN);
1016
1017 if (ret == 0)
1018 mtdswap_rb_add(d, eb, MTDSWAP_CLEAN);
1019 else if (ret != -EIO && ret != -EBADMSG)
1020 mtdswap_rb_add(d, eb, MTDSWAP_DIRTY);
1021
1022 return 0;
1023 }
1024
1025 static void mtdswap_background(struct mtd_blktrans_dev *dev)
1026 {
1027 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1028 int ret;
1029
1030 while (1) {
1031 ret = mtdswap_gc(d, 1);
1032 if (ret || mtd_blktrans_cease_background(dev))
1033 return;
1034 }
1035 }
1036
1037 static void mtdswap_cleanup(struct mtdswap_dev *d)
1038 {
1039 vfree(d->eb_data);
1040 vfree(d->revmap);
1041 vfree(d->page_data);
1042 kfree(d->oob_buf);
1043 kfree(d->page_buf);
1044 }
1045
1046 static int mtdswap_flush(struct mtd_blktrans_dev *dev)
1047 {
1048 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1049
1050 if (d->mtd->sync)
1051 d->mtd->sync(d->mtd);
1052 return 0;
1053 }
1054
1055 static unsigned int mtdswap_badblocks(struct mtd_info *mtd, uint64_t size)
1056 {
1057 loff_t offset;
1058 unsigned int badcnt;
1059
1060 badcnt = 0;
1061
1062 if (mtd->block_isbad)
1063 for (offset = 0; offset < size; offset += mtd->erasesize)
1064 if (mtd->block_isbad(mtd, offset))
1065 badcnt++;
1066
1067 return badcnt;
1068 }
1069
1070 static int mtdswap_writesect(struct mtd_blktrans_dev *dev,
1071 unsigned long page, char *buf)
1072 {
1073 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1074 unsigned int newblock, mapped;
1075 struct swap_eb *eb;
1076 int ret;
1077
1078 d->sect_write_count++;
1079
1080 if (d->spare_eblks < MIN_SPARE_EBLOCKS)
1081 return -ENOSPC;
1082
1083 if (header) {
1084 /* Ignore writes to the header page */
1085 if (unlikely(page == 0))
1086 return 0;
1087
1088 page--;
1089 }
1090
1091 mapped = d->page_data[page];
1092 if (mapped <= BLOCK_MAX) {
1093 eb = d->eb_data + (mapped / d->pages_per_eblk);
1094 eb->active_count--;
1095 mtdswap_store_eb(d, eb);
1096 d->page_data[page] = BLOCK_UNDEF;
1097 d->revmap[mapped] = PAGE_UNDEF;
1098 }
1099
1100 ret = mtdswap_write_block(d, buf, page, &newblock, 0);
1101 d->mtd_write_count++;
1102
1103 if (ret < 0)
1104 return ret;
1105
1106 eb = d->eb_data + (newblock / d->pages_per_eblk);
1107 d->page_data[page] = newblock;
1108
1109 return 0;
1110 }
1111
1112 /* Provide a dummy swap header for the kernel */
1113 static int mtdswap_auto_header(struct mtdswap_dev *d, char *buf)
1114 {
1115 union swap_header *hd = (union swap_header *)(buf);
1116
1117 memset(buf, 0, PAGE_SIZE - 10);
1118
1119 hd->info.version = 1;
1120 hd->info.last_page = d->mbd_dev->size - 1;
1121 hd->info.nr_badpages = 0;
1122
1123 memcpy(buf + PAGE_SIZE - 10, "SWAPSPACE2", 10);
1124
1125 return 0;
1126 }
1127
1128 static int mtdswap_readsect(struct mtd_blktrans_dev *dev,
1129 unsigned long page, char *buf)
1130 {
1131 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1132 struct mtd_info *mtd = d->mtd;
1133 unsigned int realblock, retries;
1134 loff_t readpos;
1135 struct swap_eb *eb;
1136 size_t retlen;
1137 int ret;
1138
1139 d->sect_read_count++;
1140
1141 if (header) {
1142 if (unlikely(page == 0))
1143 return mtdswap_auto_header(d, buf);
1144
1145 page--;
1146 }
1147
1148 realblock = d->page_data[page];
1149 if (realblock > BLOCK_MAX) {
1150 memset(buf, 0x0, PAGE_SIZE);
1151 if (realblock == BLOCK_UNDEF)
1152 return 0;
1153 else
1154 return -EIO;
1155 }
1156
1157 eb = d->eb_data + (realblock / d->pages_per_eblk);
1158 BUG_ON(d->revmap[realblock] == PAGE_UNDEF);
1159
1160 readpos = (loff_t)realblock << PAGE_SHIFT;
1161 retries = 0;
1162
1163 retry:
1164 ret = mtd->read(mtd, readpos, PAGE_SIZE, &retlen, buf);
1165
1166 d->mtd_read_count++;
1167 if (ret == -EUCLEAN) {
1168 eb->flags |= EBLOCK_BITFLIP;
1169 mtdswap_rb_add(d, eb, MTDSWAP_BITFLIP);
1170 ret = 0;
1171 }
1172
1173 if (ret < 0) {
1174 dev_err(d->dev, "Read error %d\n", ret);
1175 eb->flags |= EBLOCK_READERR;
1176 mtdswap_rb_add(d, eb, MTDSWAP_FAILING);
1177 retries++;
1178 if (retries < MTDSWAP_IO_RETRIES)
1179 goto retry;
1180
1181 return ret;
1182 }
1183
1184 if (retlen != PAGE_SIZE) {
1185 dev_err(d->dev, "Short read %zd\n", retlen);
1186 return -EIO;
1187 }
1188
1189 return 0;
1190 }
1191
1192 static int mtdswap_discard(struct mtd_blktrans_dev *dev, unsigned long first,
1193 unsigned nr_pages)
1194 {
1195 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1196 unsigned long page;
1197 struct swap_eb *eb;
1198 unsigned int mapped;
1199
1200 d->discard_count++;
1201
1202 for (page = first; page < first + nr_pages; page++) {
1203 mapped = d->page_data[page];
1204 if (mapped <= BLOCK_MAX) {
1205 eb = d->eb_data + (mapped / d->pages_per_eblk);
1206 eb->active_count--;
1207 mtdswap_store_eb(d, eb);
1208 d->page_data[page] = BLOCK_UNDEF;
1209 d->revmap[mapped] = PAGE_UNDEF;
1210 d->discard_page_count++;
1211 } else if (mapped == BLOCK_ERROR) {
1212 d->page_data[page] = BLOCK_UNDEF;
1213 d->discard_page_count++;
1214 }
1215 }
1216
1217 return 0;
1218 }
1219
1220 static int mtdswap_show(struct seq_file *s, void *data)
1221 {
1222 struct mtdswap_dev *d = (struct mtdswap_dev *) s->private;
1223 unsigned long sum;
1224 unsigned int count[MTDSWAP_TREE_CNT];
1225 unsigned int min[MTDSWAP_TREE_CNT];
1226 unsigned int max[MTDSWAP_TREE_CNT];
1227 unsigned int i, cw = 0, cwp = 0, cwecount = 0, bb_cnt, mapped, pages;
1228 uint64_t use_size;
1229 char *name[] = {"clean", "used", "low", "high", "dirty", "bitflip",
1230 "failing"};
1231
1232 mutex_lock(&d->mbd_dev->lock);
1233
1234 for (i = 0; i < MTDSWAP_TREE_CNT; i++) {
1235 struct rb_root *root = &d->trees[i].root;
1236
1237 if (root->rb_node) {
1238 count[i] = d->trees[i].count;
1239 min[i] = rb_entry(rb_first(root), struct swap_eb,
1240 rb)->erase_count;
1241 max[i] = rb_entry(rb_last(root), struct swap_eb,
1242 rb)->erase_count;
1243 } else
1244 count[i] = 0;
1245 }
1246
1247 if (d->curr_write) {
1248 cw = 1;
1249 cwp = d->curr_write_pos;
1250 cwecount = d->curr_write->erase_count;
1251 }
1252
1253 sum = 0;
1254 for (i = 0; i < d->eblks; i++)
1255 sum += d->eb_data[i].erase_count;
1256
1257 use_size = (uint64_t)d->eblks * d->mtd->erasesize;
1258 bb_cnt = mtdswap_badblocks(d->mtd, use_size);
1259
1260 mapped = 0;
1261 pages = d->mbd_dev->size;
1262 for (i = 0; i < pages; i++)
1263 if (d->page_data[i] != BLOCK_UNDEF)
1264 mapped++;
1265
1266 mutex_unlock(&d->mbd_dev->lock);
1267
1268 for (i = 0; i < MTDSWAP_TREE_CNT; i++) {
1269 if (!count[i])
1270 continue;
1271
1272 if (min[i] != max[i])
1273 seq_printf(s, "%s:\t%5d erase blocks, erased min %d, "
1274 "max %d times\n",
1275 name[i], count[i], min[i], max[i]);
1276 else
1277 seq_printf(s, "%s:\t%5d erase blocks, all erased %d "
1278 "times\n", name[i], count[i], min[i]);
1279 }
1280
1281 if (bb_cnt)
1282 seq_printf(s, "bad:\t%5u erase blocks\n", bb_cnt);
1283
1284 if (cw)
1285 seq_printf(s, "current erase block: %u pages used, %u free, "
1286 "erased %u times\n",
1287 cwp, d->pages_per_eblk - cwp, cwecount);
1288
1289 seq_printf(s, "total erasures: %lu\n", sum);
1290
1291 seq_printf(s, "\n");
1292
1293 seq_printf(s, "mtdswap_readsect count: %llu\n", d->sect_read_count);
1294 seq_printf(s, "mtdswap_writesect count: %llu\n", d->sect_write_count);
1295 seq_printf(s, "mtdswap_discard count: %llu\n", d->discard_count);
1296 seq_printf(s, "mtd read count: %llu\n", d->mtd_read_count);
1297 seq_printf(s, "mtd write count: %llu\n", d->mtd_write_count);
1298 seq_printf(s, "discarded pages count: %llu\n", d->discard_page_count);
1299
1300 seq_printf(s, "\n");
1301 seq_printf(s, "total pages: %u\n", pages);
1302 seq_printf(s, "pages mapped: %u\n", mapped);
1303
1304 return 0;
1305 }
1306
1307 static int mtdswap_open(struct inode *inode, struct file *file)
1308 {
1309 return single_open(file, mtdswap_show, inode->i_private);
1310 }
1311
1312 static const struct file_operations mtdswap_fops = {
1313 .open = mtdswap_open,
1314 .read = seq_read,
1315 .llseek = seq_lseek,
1316 .release = single_release,
1317 };
1318
1319 static int mtdswap_add_debugfs(struct mtdswap_dev *d)
1320 {
1321 struct gendisk *gd = d->mbd_dev->disk;
1322 struct device *dev = disk_to_dev(gd);
1323
1324 struct dentry *root;
1325 struct dentry *dent;
1326
1327 root = debugfs_create_dir(gd->disk_name, NULL);
1328 if (IS_ERR(root))
1329 return 0;
1330
1331 if (!root) {
1332 dev_err(dev, "failed to initialize debugfs\n");
1333 return -1;
1334 }
1335
1336 d->debugfs_root = root;
1337
1338 dent = debugfs_create_file("stats", S_IRUSR, root, d,
1339 &mtdswap_fops);
1340 if (!dent) {
1341 dev_err(d->dev, "debugfs_create_file failed\n");
1342 debugfs_remove_recursive(root);
1343 d->debugfs_root = NULL;
1344 return -1;
1345 }
1346
1347 return 0;
1348 }
1349
1350 static int mtdswap_init(struct mtdswap_dev *d, unsigned int eblocks,
1351 unsigned int spare_cnt)
1352 {
1353 struct mtd_info *mtd = d->mbd_dev->mtd;
1354 unsigned int i, eblk_bytes, pages, blocks;
1355 int ret = -ENOMEM;
1356
1357 d->mtd = mtd;
1358 d->eblks = eblocks;
1359 d->spare_eblks = spare_cnt;
1360 d->pages_per_eblk = mtd->erasesize >> PAGE_SHIFT;
1361
1362 pages = d->mbd_dev->size;
1363 blocks = eblocks * d->pages_per_eblk;
1364
1365 for (i = 0; i < MTDSWAP_TREE_CNT; i++)
1366 d->trees[i].root = RB_ROOT;
1367
1368 d->page_data = vmalloc(sizeof(int)*pages);
1369 if (!d->page_data)
1370 goto page_data_fail;
1371
1372 d->revmap = vmalloc(sizeof(int)*blocks);
1373 if (!d->revmap)
1374 goto revmap_fail;
1375
1376 eblk_bytes = sizeof(struct swap_eb)*d->eblks;
1377 d->eb_data = vzalloc(eblk_bytes);
1378 if (!d->eb_data)
1379 goto eb_data_fail;
1380
1381 for (i = 0; i < pages; i++)
1382 d->page_data[i] = BLOCK_UNDEF;
1383
1384 for (i = 0; i < blocks; i++)
1385 d->revmap[i] = PAGE_UNDEF;
1386
1387 d->page_buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1388 if (!d->page_buf)
1389 goto page_buf_fail;
1390
1391 d->oob_buf = kmalloc(2 * mtd->ecclayout->oobavail, GFP_KERNEL);
1392 if (!d->oob_buf)
1393 goto oob_buf_fail;
1394
1395 mtdswap_scan_eblks(d);
1396
1397 return 0;
1398
1399 oob_buf_fail:
1400 kfree(d->page_buf);
1401 page_buf_fail:
1402 vfree(d->eb_data);
1403 eb_data_fail:
1404 vfree(d->revmap);
1405 revmap_fail:
1406 vfree(d->page_data);
1407 page_data_fail:
1408 printk(KERN_ERR "%s: init failed (%d)\n", MTDSWAP_PREFIX, ret);
1409 return ret;
1410 }
1411
1412 static void mtdswap_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
1413 {
1414 struct mtdswap_dev *d;
1415 struct mtd_blktrans_dev *mbd_dev;
1416 char *parts;
1417 char *this_opt;
1418 unsigned long part;
1419 unsigned int eblocks, eavailable, bad_blocks, spare_cnt;
1420 uint64_t swap_size, use_size, size_limit;
1421 struct nand_ecclayout *oinfo;
1422 int ret;
1423
1424 parts = &partitions[0];
1425 if (!*parts)
1426 return;
1427
1428 while ((this_opt = strsep(&parts, ",")) != NULL) {
1429 if (strict_strtoul(this_opt, 0, &part) < 0)
1430 return;
1431
1432 if (mtd->index == part)
1433 break;
1434 }
1435
1436 if (mtd->index != part)
1437 return;
1438
1439 if (mtd->erasesize < PAGE_SIZE || mtd->erasesize % PAGE_SIZE) {
1440 printk(KERN_ERR "%s: Erase size %u not multiple of PAGE_SIZE "
1441 "%lu\n", MTDSWAP_PREFIX, mtd->erasesize, PAGE_SIZE);
1442 return;
1443 }
1444
1445 if (PAGE_SIZE % mtd->writesize || mtd->writesize > PAGE_SIZE) {
1446 printk(KERN_ERR "%s: PAGE_SIZE %lu not multiple of write size"
1447 " %u\n", MTDSWAP_PREFIX, PAGE_SIZE, mtd->writesize);
1448 return;
1449 }
1450
1451 oinfo = mtd->ecclayout;
1452 if (!oinfo) {
1453 printk(KERN_ERR "%s: mtd%d does not have OOB\n",
1454 MTDSWAP_PREFIX, mtd->index);
1455 return;
1456 }
1457
1458 if (!mtd->oobsize || oinfo->oobavail < MTDSWAP_OOBSIZE) {
1459 printk(KERN_ERR "%s: Not enough free bytes in OOB, "
1460 "%d available, %zu needed.\n",
1461 MTDSWAP_PREFIX, oinfo->oobavail, MTDSWAP_OOBSIZE);
1462 return;
1463 }
1464
1465 if (spare_eblocks > 100)
1466 spare_eblocks = 100;
1467
1468 use_size = mtd->size;
1469 size_limit = (uint64_t) BLOCK_MAX * PAGE_SIZE;
1470
1471 if (mtd->size > size_limit) {
1472 printk(KERN_WARNING "%s: Device too large. Limiting size to "
1473 "%llu bytes\n", MTDSWAP_PREFIX, size_limit);
1474 use_size = size_limit;
1475 }
1476
1477 eblocks = mtd_div_by_eb(use_size, mtd);
1478 use_size = eblocks * mtd->erasesize;
1479 bad_blocks = mtdswap_badblocks(mtd, use_size);
1480 eavailable = eblocks - bad_blocks;
1481
1482 if (eavailable < MIN_ERASE_BLOCKS) {
1483 printk(KERN_ERR "%s: Not enough erase blocks. %u available, "
1484 "%d needed\n", MTDSWAP_PREFIX, eavailable,
1485 MIN_ERASE_BLOCKS);
1486 return;
1487 }
1488
1489 spare_cnt = div_u64((uint64_t)eavailable * spare_eblocks, 100);
1490
1491 if (spare_cnt < MIN_SPARE_EBLOCKS)
1492 spare_cnt = MIN_SPARE_EBLOCKS;
1493
1494 if (spare_cnt > eavailable - 1)
1495 spare_cnt = eavailable - 1;
1496
1497 swap_size = (uint64_t)(eavailable - spare_cnt) * mtd->erasesize +
1498 (header ? PAGE_SIZE : 0);
1499
1500 printk(KERN_INFO "%s: Enabling MTD swap on device %lu, size %llu KB, "
1501 "%u spare, %u bad blocks\n",
1502 MTDSWAP_PREFIX, part, swap_size / 1024, spare_cnt, bad_blocks);
1503
1504 d = kzalloc(sizeof(struct mtdswap_dev), GFP_KERNEL);
1505 if (!d)
1506 return;
1507
1508 mbd_dev = kzalloc(sizeof(struct mtd_blktrans_dev), GFP_KERNEL);
1509 if (!mbd_dev) {
1510 kfree(d);
1511 return;
1512 }
1513
1514 d->mbd_dev = mbd_dev;
1515 mbd_dev->priv = d;
1516
1517 mbd_dev->mtd = mtd;
1518 mbd_dev->devnum = mtd->index;
1519 mbd_dev->size = swap_size >> PAGE_SHIFT;
1520 mbd_dev->tr = tr;
1521
1522 if (!(mtd->flags & MTD_WRITEABLE))
1523 mbd_dev->readonly = 1;
1524
1525 if (mtdswap_init(d, eblocks, spare_cnt) < 0)
1526 goto init_failed;
1527
1528 if (add_mtd_blktrans_dev(mbd_dev) < 0)
1529 goto cleanup;
1530
1531 d->dev = disk_to_dev(mbd_dev->disk);
1532
1533 ret = mtdswap_add_debugfs(d);
1534 if (ret < 0)
1535 goto debugfs_failed;
1536
1537 return;
1538
1539 debugfs_failed:
1540 del_mtd_blktrans_dev(mbd_dev);
1541
1542 cleanup:
1543 mtdswap_cleanup(d);
1544
1545 init_failed:
1546 kfree(mbd_dev);
1547 kfree(d);
1548 }
1549
1550 static void mtdswap_remove_dev(struct mtd_blktrans_dev *dev)
1551 {
1552 struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
1553
1554 debugfs_remove_recursive(d->debugfs_root);
1555 del_mtd_blktrans_dev(dev);
1556 mtdswap_cleanup(d);
1557 kfree(d);
1558 }
1559
1560 static struct mtd_blktrans_ops mtdswap_ops = {
1561 .name = "mtdswap",
1562 .major = 0,
1563 .part_bits = 0,
1564 .blksize = PAGE_SIZE,
1565 .flush = mtdswap_flush,
1566 .readsect = mtdswap_readsect,
1567 .writesect = mtdswap_writesect,
1568 .discard = mtdswap_discard,
1569 .background = mtdswap_background,
1570 .add_mtd = mtdswap_add_mtd,
1571 .remove_dev = mtdswap_remove_dev,
1572 .owner = THIS_MODULE,
1573 };
1574
1575 static int __init mtdswap_modinit(void)
1576 {
1577 return register_mtd_blktrans(&mtdswap_ops);
1578 }
1579
1580 static void __exit mtdswap_modexit(void)
1581 {
1582 deregister_mtd_blktrans(&mtdswap_ops);
1583 }
1584
1585 module_init(mtdswap_modinit);
1586 module_exit(mtdswap_modexit);
1587
1588
1589 MODULE_LICENSE("GPL");
1590 MODULE_AUTHOR("Jarkko Lavinen <jarkko.lavinen@nokia.com>");
1591 MODULE_DESCRIPTION("Block device access to an MTD suitable for using as "
1592 "swap space");
linux-next