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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Bad block management
4 *
5 * - Heavily based on MD badblocks code from Neil Brown
6 *
7 * Copyright (c) 2015, Intel Corporation.
8 */
9
10#include <linux/badblocks.h>
11#include <linux/seqlock.h>
12#include <linux/device.h>
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include <linux/stddef.h>
16#include <linux/types.h>
17#include <linux/slab.h>
18
19/**
20 * badblocks_check() - check a given range for bad sectors
21 * @bb: the badblocks structure that holds all badblock information
22 * @s: sector (start) at which to check for badblocks
23 * @sectors: number of sectors to check for badblocks
24 * @first_bad: pointer to store location of the first badblock
25 * @bad_sectors: pointer to store number of badblocks after @first_bad
26 *
27 * We can record which blocks on each device are 'bad' and so just
28 * fail those blocks, or that stripe, rather than the whole device.
29 * Entries in the bad-block table are 64bits wide. This comprises:
30 * Length of bad-range, in sectors: 0-511 for lengths 1-512
31 * Start of bad-range, sector offset, 54 bits (allows 8 exbibytes)
32 * A 'shift' can be set so that larger blocks are tracked and
33 * consequently larger devices can be covered.
34 * 'Acknowledged' flag - 1 bit. - the most significant bit.
35 *
36 * Locking of the bad-block table uses a seqlock so badblocks_check
37 * might need to retry if it is very unlucky.
38 * We will sometimes want to check for bad blocks in a bi_end_io function,
39 * so we use the write_seqlock_irq variant.
40 *
41 * When looking for a bad block we specify a range and want to
42 * know if any block in the range is bad. So we binary-search
43 * to the last range that starts at-or-before the given endpoint,
44 * (or "before the sector after the target range")
45 * then see if it ends after the given start.
46 *
47 * Return:
48 * 0: there are no known bad blocks in the range
49 * 1: there are known bad block which are all acknowledged
50 * -1: there are bad blocks which have not yet been acknowledged in metadata.
51 * plus the start/length of the first bad section we overlap.
52 */
53int badblocks_check(struct badblocks *bb, sector_t s, int sectors,
54 sector_t *first_bad, int *bad_sectors)
55{
56 int hi;
57 int lo;
58 u64 *p = bb->page;
59 int rv;
60 sector_t target = s + sectors;
61 unsigned seq;
62
63 if (bb->shift > 0) {
64 /* round the start down, and the end up */
65 s >>= bb->shift;
66 target += (1<<bb->shift) - 1;
67 target >>= bb->shift;
68 }
69 /* 'target' is now the first block after the bad range */
70
71retry:
72 seq = read_seqbegin(&bb->lock);
73 lo = 0;
74 rv = 0;
75 hi = bb->count;
76
77 /* Binary search between lo and hi for 'target'
78 * i.e. for the last range that starts before 'target'
79 */
80 /* INVARIANT: ranges before 'lo' and at-or-after 'hi'
81 * are known not to be the last range before target.
82 * VARIANT: hi-lo is the number of possible
83 * ranges, and decreases until it reaches 1
84 */
85 while (hi - lo > 1) {
86 int mid = (lo + hi) / 2;
87 sector_t a = BB_OFFSET(p[mid]);
88
89 if (a < target)
90 /* This could still be the one, earlier ranges
91 * could not.
92 */
93 lo = mid;
94 else
95 /* This and later ranges are definitely out. */
96 hi = mid;
97 }
98 /* 'lo' might be the last that started before target, but 'hi' isn't */
99 if (hi > lo) {
100 /* need to check all range that end after 's' to see if
101 * any are unacknowledged.
102 */
103 while (lo >= 0 &&
104 BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) {
105 if (BB_OFFSET(p[lo]) < target) {
106 /* starts before the end, and finishes after
107 * the start, so they must overlap
108 */
109 if (rv != -1 && BB_ACK(p[lo]))
110 rv = 1;
111 else
112 rv = -1;
113 *first_bad = BB_OFFSET(p[lo]);
114 *bad_sectors = BB_LEN(p[lo]);
115 }
116 lo--;
117 }
118 }
119
120 if (read_seqretry(&bb->lock, seq))
121 goto retry;
122
123 return rv;
124}
125EXPORT_SYMBOL_GPL(badblocks_check);
126
127static void badblocks_update_acked(struct badblocks *bb)
128{
129 u64 *p = bb->page;
130 int i;
131 bool unacked = false;
132
133 if (!bb->unacked_exist)
134 return;
135
136 for (i = 0; i < bb->count ; i++) {
137 if (!BB_ACK(p[i])) {
138 unacked = true;
139 break;
140 }
141 }
142
143 if (!unacked)
144 bb->unacked_exist = 0;
145}
146
147/**
148 * badblocks_set() - Add a range of bad blocks to the table.
149 * @bb: the badblocks structure that holds all badblock information
150 * @s: first sector to mark as bad
151 * @sectors: number of sectors to mark as bad
152 * @acknowledged: weather to mark the bad sectors as acknowledged
153 *
154 * This might extend the table, or might contract it if two adjacent ranges
155 * can be merged. We binary-search to find the 'insertion' point, then
156 * decide how best to handle it.
157 *
158 * Return:
159 * 0: success
160 * 1: failed to set badblocks (out of space)
161 */
162int badblocks_set(struct badblocks *bb, sector_t s, int sectors,
163 int acknowledged)
164{
165 u64 *p;
166 int lo, hi;
167 int rv = 0;
168 unsigned long flags;
169
170 if (bb->shift < 0)
171 /* badblocks are disabled */
172 return 1;
173
174 if (bb->shift) {
175 /* round the start down, and the end up */
176 sector_t next = s + sectors;
177
178 s >>= bb->shift;
179 next += (1<<bb->shift) - 1;
180 next >>= bb->shift;
181 sectors = next - s;
182 }
183
184 write_seqlock_irqsave(&bb->lock, flags);
185
186 p = bb->page;
187 lo = 0;
188 hi = bb->count;
189 /* Find the last range that starts at-or-before 's' */
190 while (hi - lo > 1) {
191 int mid = (lo + hi) / 2;
192 sector_t a = BB_OFFSET(p[mid]);
193
194 if (a <= s)
195 lo = mid;
196 else
197 hi = mid;
198 }
199 if (hi > lo && BB_OFFSET(p[lo]) > s)
200 hi = lo;
201
202 if (hi > lo) {
203 /* we found a range that might merge with the start
204 * of our new range
205 */
206 sector_t a = BB_OFFSET(p[lo]);
207 sector_t e = a + BB_LEN(p[lo]);
208 int ack = BB_ACK(p[lo]);
209
210 if (e >= s) {
211 /* Yes, we can merge with a previous range */
212 if (s == a && s + sectors >= e)
213 /* new range covers old */
214 ack = acknowledged;
215 else
216 ack = ack && acknowledged;
217
218 if (e < s + sectors)
219 e = s + sectors;
220 if (e - a <= BB_MAX_LEN) {
221 p[lo] = BB_MAKE(a, e-a, ack);
222 s = e;
223 } else {
224 /* does not all fit in one range,
225 * make p[lo] maximal
226 */
227 if (BB_LEN(p[lo]) != BB_MAX_LEN)
228 p[lo] = BB_MAKE(a, BB_MAX_LEN, ack);
229 s = a + BB_MAX_LEN;
230 }
231 sectors = e - s;
232 }
233 }
234 if (sectors && hi < bb->count) {
235 /* 'hi' points to the first range that starts after 's'.
236 * Maybe we can merge with the start of that range
237 */
238 sector_t a = BB_OFFSET(p[hi]);
239 sector_t e = a + BB_LEN(p[hi]);
240 int ack = BB_ACK(p[hi]);
241
242 if (a <= s + sectors) {
243 /* merging is possible */
244 if (e <= s + sectors) {
245 /* full overlap */
246 e = s + sectors;
247 ack = acknowledged;
248 } else
249 ack = ack && acknowledged;
250
251 a = s;
252 if (e - a <= BB_MAX_LEN) {
253 p[hi] = BB_MAKE(a, e-a, ack);
254 s = e;
255 } else {
256 p[hi] = BB_MAKE(a, BB_MAX_LEN, ack);
257 s = a + BB_MAX_LEN;
258 }
259 sectors = e - s;
260 lo = hi;
261 hi++;
262 }
263 }
264 if (sectors == 0 && hi < bb->count) {
265 /* we might be able to combine lo and hi */
266 /* Note: 's' is at the end of 'lo' */
267 sector_t a = BB_OFFSET(p[hi]);
268 int lolen = BB_LEN(p[lo]);
269 int hilen = BB_LEN(p[hi]);
270 int newlen = lolen + hilen - (s - a);
271
272 if (s >= a && newlen < BB_MAX_LEN) {
273 /* yes, we can combine them */
274 int ack = BB_ACK(p[lo]) && BB_ACK(p[hi]);
275
276 p[lo] = BB_MAKE(BB_OFFSET(p[lo]), newlen, ack);
277 memmove(p + hi, p + hi + 1,
278 (bb->count - hi - 1) * 8);
279 bb->count--;
280 }
281 }
282 while (sectors) {
283 /* didn't merge (it all).
284 * Need to add a range just before 'hi'
285 */
286 if (bb->count >= MAX_BADBLOCKS) {
287 /* No room for more */
288 rv = 1;
289 break;
290 } else {
291 int this_sectors = sectors;
292
293 memmove(p + hi + 1, p + hi,
294 (bb->count - hi) * 8);
295 bb->count++;
296
297 if (this_sectors > BB_MAX_LEN)
298 this_sectors = BB_MAX_LEN;
299 p[hi] = BB_MAKE(s, this_sectors, acknowledged);
300 sectors -= this_sectors;
301 s += this_sectors;
302 }
303 }
304
305 bb->changed = 1;
306 if (!acknowledged)
307 bb->unacked_exist = 1;
308 else
309 badblocks_update_acked(bb);
310 write_sequnlock_irqrestore(&bb->lock, flags);
311
312 return rv;
313}
314EXPORT_SYMBOL_GPL(badblocks_set);
315
316/**
317 * badblocks_clear() - Remove a range of bad blocks to the table.
318 * @bb: the badblocks structure that holds all badblock information
319 * @s: first sector to mark as bad
320 * @sectors: number of sectors to mark as bad
321 *
322 * This may involve extending the table if we spilt a region,
323 * but it must not fail. So if the table becomes full, we just
324 * drop the remove request.
325 *
326 * Return:
327 * 0: success
328 * 1: failed to clear badblocks
329 */
330int badblocks_clear(struct badblocks *bb, sector_t s, int sectors)
331{
332 u64 *p;
333 int lo, hi;
334 sector_t target = s + sectors;
335 int rv = 0;
336
337 if (bb->shift > 0) {
338 /* When clearing we round the start up and the end down.
339 * This should not matter as the shift should align with
340 * the block size and no rounding should ever be needed.
341 * However it is better the think a block is bad when it
342 * isn't than to think a block is not bad when it is.
343 */
344 s += (1<<bb->shift) - 1;
345 s >>= bb->shift;
346 target >>= bb->shift;
347 }
348
349 write_seqlock_irq(&bb->lock);
350
351 p = bb->page;
352 lo = 0;
353 hi = bb->count;
354 /* Find the last range that starts before 'target' */
355 while (hi - lo > 1) {
356 int mid = (lo + hi) / 2;
357 sector_t a = BB_OFFSET(p[mid]);
358
359 if (a < target)
360 lo = mid;
361 else
362 hi = mid;
363 }
364 if (hi > lo) {
365 /* p[lo] is the last range that could overlap the
366 * current range. Earlier ranges could also overlap,
367 * but only this one can overlap the end of the range.
368 */
369 if ((BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > target) &&
370 (BB_OFFSET(p[lo]) < target)) {
371 /* Partial overlap, leave the tail of this range */
372 int ack = BB_ACK(p[lo]);
373 sector_t a = BB_OFFSET(p[lo]);
374 sector_t end = a + BB_LEN(p[lo]);
375
376 if (a < s) {
377 /* we need to split this range */
378 if (bb->count >= MAX_BADBLOCKS) {
379 rv = -ENOSPC;
380 goto out;
381 }
382 memmove(p+lo+1, p+lo, (bb->count - lo) * 8);
383 bb->count++;
384 p[lo] = BB_MAKE(a, s-a, ack);
385 lo++;
386 }
387 p[lo] = BB_MAKE(target, end - target, ack);
388 /* there is no longer an overlap */
389 hi = lo;
390 lo--;
391 }
392 while (lo >= 0 &&
393 (BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) &&
394 (BB_OFFSET(p[lo]) < target)) {
395 /* This range does overlap */
396 if (BB_OFFSET(p[lo]) < s) {
397 /* Keep the early parts of this range. */
398 int ack = BB_ACK(p[lo]);
399 sector_t start = BB_OFFSET(p[lo]);
400
401 p[lo] = BB_MAKE(start, s - start, ack);
402 /* now low doesn't overlap, so.. */
403 break;
404 }
405 lo--;
406 }
407 /* 'lo' is strictly before, 'hi' is strictly after,
408 * anything between needs to be discarded
409 */
410 if (hi - lo > 1) {
411 memmove(p+lo+1, p+hi, (bb->count - hi) * 8);
412 bb->count -= (hi - lo - 1);
413 }
414 }
415
416 badblocks_update_acked(bb);
417 bb->changed = 1;
418out:
419 write_sequnlock_irq(&bb->lock);
420 return rv;
421}
422EXPORT_SYMBOL_GPL(badblocks_clear);
423
424/**
425 * ack_all_badblocks() - Acknowledge all bad blocks in a list.
426 * @bb: the badblocks structure that holds all badblock information
427 *
428 * This only succeeds if ->changed is clear. It is used by
429 * in-kernel metadata updates
430 */
431void ack_all_badblocks(struct badblocks *bb)
432{
433 if (bb->page == NULL || bb->changed)
434 /* no point even trying */
435 return;
436 write_seqlock_irq(&bb->lock);
437
438 if (bb->changed == 0 && bb->unacked_exist) {
439 u64 *p = bb->page;
440 int i;
441
442 for (i = 0; i < bb->count ; i++) {
443 if (!BB_ACK(p[i])) {
444 sector_t start = BB_OFFSET(p[i]);
445 int len = BB_LEN(p[i]);
446
447 p[i] = BB_MAKE(start, len, 1);
448 }
449 }
450 bb->unacked_exist = 0;
451 }
452 write_sequnlock_irq(&bb->lock);
453}
454EXPORT_SYMBOL_GPL(ack_all_badblocks);
455
456/**
457 * badblocks_show() - sysfs access to bad-blocks list
458 * @bb: the badblocks structure that holds all badblock information
459 * @page: buffer received from sysfs
460 * @unack: weather to show unacknowledged badblocks
461 *
462 * Return:
463 * Length of returned data
464 */
465ssize_t badblocks_show(struct badblocks *bb, char *page, int unack)
466{
467 size_t len;
468 int i;
469 u64 *p = bb->page;
470 unsigned seq;
471
472 if (bb->shift < 0)
473 return 0;
474
475retry:
476 seq = read_seqbegin(&bb->lock);
477
478 len = 0;
479 i = 0;
480
481 while (len < PAGE_SIZE && i < bb->count) {
482 sector_t s = BB_OFFSET(p[i]);
483 unsigned int length = BB_LEN(p[i]);
484 int ack = BB_ACK(p[i]);
485
486 i++;
487
488 if (unack && ack)
489 continue;
490
491 len += snprintf(page+len, PAGE_SIZE-len, "%llu %u\n",
492 (unsigned long long)s << bb->shift,
493 length << bb->shift);
494 }
495 if (unack && len == 0)
496 bb->unacked_exist = 0;
497
498 if (read_seqretry(&bb->lock, seq))
499 goto retry;
500
501 return len;
502}
503EXPORT_SYMBOL_GPL(badblocks_show);
504
505/**
506 * badblocks_store() - sysfs access to bad-blocks list
507 * @bb: the badblocks structure that holds all badblock information
508 * @page: buffer received from sysfs
509 * @len: length of data received from sysfs
510 * @unack: weather to show unacknowledged badblocks
511 *
512 * Return:
513 * Length of the buffer processed or -ve error.
514 */
515ssize_t badblocks_store(struct badblocks *bb, const char *page, size_t len,
516 int unack)
517{
518 unsigned long long sector;
519 int length;
520 char newline;
521
522 switch (sscanf(page, "%llu %d%c", §or, &length, &newline)) {
523 case 3:
524 if (newline != '\n')
525 return -EINVAL;
526 fallthrough;
527 case 2:
528 if (length <= 0)
529 return -EINVAL;
530 break;
531 default:
532 return -EINVAL;
533 }
534
535 if (badblocks_set(bb, sector, length, !unack))
536 return -ENOSPC;
537 else
538 return len;
539}
540EXPORT_SYMBOL_GPL(badblocks_store);
541
542static int __badblocks_init(struct device *dev, struct badblocks *bb,
543 int enable)
544{
545 bb->dev = dev;
546 bb->count = 0;
547 if (enable)
548 bb->shift = 0;
549 else
550 bb->shift = -1;
551 if (dev)
552 bb->page = devm_kzalloc(dev, PAGE_SIZE, GFP_KERNEL);
553 else
554 bb->page = kzalloc(PAGE_SIZE, GFP_KERNEL);
555 if (!bb->page) {
556 bb->shift = -1;
557 return -ENOMEM;
558 }
559 seqlock_init(&bb->lock);
560
561 return 0;
562}
563
564/**
565 * badblocks_init() - initialize the badblocks structure
566 * @bb: the badblocks structure that holds all badblock information
567 * @enable: weather to enable badblocks accounting
568 *
569 * Return:
570 * 0: success
571 * -ve errno: on error
572 */
573int badblocks_init(struct badblocks *bb, int enable)
574{
575 return __badblocks_init(NULL, bb, enable);
576}
577EXPORT_SYMBOL_GPL(badblocks_init);
578
579int devm_init_badblocks(struct device *dev, struct badblocks *bb)
580{
581 if (!bb)
582 return -EINVAL;
583 return __badblocks_init(dev, bb, 1);
584}
585EXPORT_SYMBOL_GPL(devm_init_badblocks);
586
587/**
588 * badblocks_exit() - free the badblocks structure
589 * @bb: the badblocks structure that holds all badblock information
590 */
591void badblocks_exit(struct badblocks *bb)
592{
593 if (!bb)
594 return;
595 if (bb->dev)
596 devm_kfree(bb->dev, bb->page);
597 else
598 kfree(bb->page);
599 bb->page = NULL;
600}
601EXPORT_SYMBOL_GPL(badblocks_exit);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Bad block management
4 *
5 * - Heavily based on MD badblocks code from Neil Brown
6 *
7 * Copyright (c) 2015, Intel Corporation.
8 */
9
10#include <linux/badblocks.h>
11#include <linux/seqlock.h>
12#include <linux/device.h>
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include <linux/stddef.h>
16#include <linux/types.h>
17#include <linux/slab.h>
18
19/**
20 * badblocks_check() - check a given range for bad sectors
21 * @bb: the badblocks structure that holds all badblock information
22 * @s: sector (start) at which to check for badblocks
23 * @sectors: number of sectors to check for badblocks
24 * @first_bad: pointer to store location of the first badblock
25 * @bad_sectors: pointer to store number of badblocks after @first_bad
26 *
27 * We can record which blocks on each device are 'bad' and so just
28 * fail those blocks, or that stripe, rather than the whole device.
29 * Entries in the bad-block table are 64bits wide. This comprises:
30 * Length of bad-range, in sectors: 0-511 for lengths 1-512
31 * Start of bad-range, sector offset, 54 bits (allows 8 exbibytes)
32 * A 'shift' can be set so that larger blocks are tracked and
33 * consequently larger devices can be covered.
34 * 'Acknowledged' flag - 1 bit. - the most significant bit.
35 *
36 * Locking of the bad-block table uses a seqlock so badblocks_check
37 * might need to retry if it is very unlucky.
38 * We will sometimes want to check for bad blocks in a bi_end_io function,
39 * so we use the write_seqlock_irq variant.
40 *
41 * When looking for a bad block we specify a range and want to
42 * know if any block in the range is bad. So we binary-search
43 * to the last range that starts at-or-before the given endpoint,
44 * (or "before the sector after the target range")
45 * then see if it ends after the given start.
46 *
47 * Return:
48 * 0: there are no known bad blocks in the range
49 * 1: there are known bad block which are all acknowledged
50 * -1: there are bad blocks which have not yet been acknowledged in metadata.
51 * plus the start/length of the first bad section we overlap.
52 */
53int badblocks_check(struct badblocks *bb, sector_t s, int sectors,
54 sector_t *first_bad, int *bad_sectors)
55{
56 int hi;
57 int lo;
58 u64 *p = bb->page;
59 int rv;
60 sector_t target = s + sectors;
61 unsigned seq;
62
63 if (bb->shift > 0) {
64 /* round the start down, and the end up */
65 s >>= bb->shift;
66 target += (1<<bb->shift) - 1;
67 target >>= bb->shift;
68 sectors = target - s;
69 }
70 /* 'target' is now the first block after the bad range */
71
72retry:
73 seq = read_seqbegin(&bb->lock);
74 lo = 0;
75 rv = 0;
76 hi = bb->count;
77
78 /* Binary search between lo and hi for 'target'
79 * i.e. for the last range that starts before 'target'
80 */
81 /* INVARIANT: ranges before 'lo' and at-or-after 'hi'
82 * are known not to be the last range before target.
83 * VARIANT: hi-lo is the number of possible
84 * ranges, and decreases until it reaches 1
85 */
86 while (hi - lo > 1) {
87 int mid = (lo + hi) / 2;
88 sector_t a = BB_OFFSET(p[mid]);
89
90 if (a < target)
91 /* This could still be the one, earlier ranges
92 * could not.
93 */
94 lo = mid;
95 else
96 /* This and later ranges are definitely out. */
97 hi = mid;
98 }
99 /* 'lo' might be the last that started before target, but 'hi' isn't */
100 if (hi > lo) {
101 /* need to check all range that end after 's' to see if
102 * any are unacknowledged.
103 */
104 while (lo >= 0 &&
105 BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) {
106 if (BB_OFFSET(p[lo]) < target) {
107 /* starts before the end, and finishes after
108 * the start, so they must overlap
109 */
110 if (rv != -1 && BB_ACK(p[lo]))
111 rv = 1;
112 else
113 rv = -1;
114 *first_bad = BB_OFFSET(p[lo]);
115 *bad_sectors = BB_LEN(p[lo]);
116 }
117 lo--;
118 }
119 }
120
121 if (read_seqretry(&bb->lock, seq))
122 goto retry;
123
124 return rv;
125}
126EXPORT_SYMBOL_GPL(badblocks_check);
127
128static void badblocks_update_acked(struct badblocks *bb)
129{
130 u64 *p = bb->page;
131 int i;
132 bool unacked = false;
133
134 if (!bb->unacked_exist)
135 return;
136
137 for (i = 0; i < bb->count ; i++) {
138 if (!BB_ACK(p[i])) {
139 unacked = true;
140 break;
141 }
142 }
143
144 if (!unacked)
145 bb->unacked_exist = 0;
146}
147
148/**
149 * badblocks_set() - Add a range of bad blocks to the table.
150 * @bb: the badblocks structure that holds all badblock information
151 * @s: first sector to mark as bad
152 * @sectors: number of sectors to mark as bad
153 * @acknowledged: weather to mark the bad sectors as acknowledged
154 *
155 * This might extend the table, or might contract it if two adjacent ranges
156 * can be merged. We binary-search to find the 'insertion' point, then
157 * decide how best to handle it.
158 *
159 * Return:
160 * 0: success
161 * 1: failed to set badblocks (out of space)
162 */
163int badblocks_set(struct badblocks *bb, sector_t s, int sectors,
164 int acknowledged)
165{
166 u64 *p;
167 int lo, hi;
168 int rv = 0;
169 unsigned long flags;
170
171 if (bb->shift < 0)
172 /* badblocks are disabled */
173 return 1;
174
175 if (bb->shift) {
176 /* round the start down, and the end up */
177 sector_t next = s + sectors;
178
179 s >>= bb->shift;
180 next += (1<<bb->shift) - 1;
181 next >>= bb->shift;
182 sectors = next - s;
183 }
184
185 write_seqlock_irqsave(&bb->lock, flags);
186
187 p = bb->page;
188 lo = 0;
189 hi = bb->count;
190 /* Find the last range that starts at-or-before 's' */
191 while (hi - lo > 1) {
192 int mid = (lo + hi) / 2;
193 sector_t a = BB_OFFSET(p[mid]);
194
195 if (a <= s)
196 lo = mid;
197 else
198 hi = mid;
199 }
200 if (hi > lo && BB_OFFSET(p[lo]) > s)
201 hi = lo;
202
203 if (hi > lo) {
204 /* we found a range that might merge with the start
205 * of our new range
206 */
207 sector_t a = BB_OFFSET(p[lo]);
208 sector_t e = a + BB_LEN(p[lo]);
209 int ack = BB_ACK(p[lo]);
210
211 if (e >= s) {
212 /* Yes, we can merge with a previous range */
213 if (s == a && s + sectors >= e)
214 /* new range covers old */
215 ack = acknowledged;
216 else
217 ack = ack && acknowledged;
218
219 if (e < s + sectors)
220 e = s + sectors;
221 if (e - a <= BB_MAX_LEN) {
222 p[lo] = BB_MAKE(a, e-a, ack);
223 s = e;
224 } else {
225 /* does not all fit in one range,
226 * make p[lo] maximal
227 */
228 if (BB_LEN(p[lo]) != BB_MAX_LEN)
229 p[lo] = BB_MAKE(a, BB_MAX_LEN, ack);
230 s = a + BB_MAX_LEN;
231 }
232 sectors = e - s;
233 }
234 }
235 if (sectors && hi < bb->count) {
236 /* 'hi' points to the first range that starts after 's'.
237 * Maybe we can merge with the start of that range
238 */
239 sector_t a = BB_OFFSET(p[hi]);
240 sector_t e = a + BB_LEN(p[hi]);
241 int ack = BB_ACK(p[hi]);
242
243 if (a <= s + sectors) {
244 /* merging is possible */
245 if (e <= s + sectors) {
246 /* full overlap */
247 e = s + sectors;
248 ack = acknowledged;
249 } else
250 ack = ack && acknowledged;
251
252 a = s;
253 if (e - a <= BB_MAX_LEN) {
254 p[hi] = BB_MAKE(a, e-a, ack);
255 s = e;
256 } else {
257 p[hi] = BB_MAKE(a, BB_MAX_LEN, ack);
258 s = a + BB_MAX_LEN;
259 }
260 sectors = e - s;
261 lo = hi;
262 hi++;
263 }
264 }
265 if (sectors == 0 && hi < bb->count) {
266 /* we might be able to combine lo and hi */
267 /* Note: 's' is at the end of 'lo' */
268 sector_t a = BB_OFFSET(p[hi]);
269 int lolen = BB_LEN(p[lo]);
270 int hilen = BB_LEN(p[hi]);
271 int newlen = lolen + hilen - (s - a);
272
273 if (s >= a && newlen < BB_MAX_LEN) {
274 /* yes, we can combine them */
275 int ack = BB_ACK(p[lo]) && BB_ACK(p[hi]);
276
277 p[lo] = BB_MAKE(BB_OFFSET(p[lo]), newlen, ack);
278 memmove(p + hi, p + hi + 1,
279 (bb->count - hi - 1) * 8);
280 bb->count--;
281 }
282 }
283 while (sectors) {
284 /* didn't merge (it all).
285 * Need to add a range just before 'hi'
286 */
287 if (bb->count >= MAX_BADBLOCKS) {
288 /* No room for more */
289 rv = 1;
290 break;
291 } else {
292 int this_sectors = sectors;
293
294 memmove(p + hi + 1, p + hi,
295 (bb->count - hi) * 8);
296 bb->count++;
297
298 if (this_sectors > BB_MAX_LEN)
299 this_sectors = BB_MAX_LEN;
300 p[hi] = BB_MAKE(s, this_sectors, acknowledged);
301 sectors -= this_sectors;
302 s += this_sectors;
303 }
304 }
305
306 bb->changed = 1;
307 if (!acknowledged)
308 bb->unacked_exist = 1;
309 else
310 badblocks_update_acked(bb);
311 write_sequnlock_irqrestore(&bb->lock, flags);
312
313 return rv;
314}
315EXPORT_SYMBOL_GPL(badblocks_set);
316
317/**
318 * badblocks_clear() - Remove a range of bad blocks to the table.
319 * @bb: the badblocks structure that holds all badblock information
320 * @s: first sector to mark as bad
321 * @sectors: number of sectors to mark as bad
322 *
323 * This may involve extending the table if we spilt a region,
324 * but it must not fail. So if the table becomes full, we just
325 * drop the remove request.
326 *
327 * Return:
328 * 0: success
329 * 1: failed to clear badblocks
330 */
331int badblocks_clear(struct badblocks *bb, sector_t s, int sectors)
332{
333 u64 *p;
334 int lo, hi;
335 sector_t target = s + sectors;
336 int rv = 0;
337
338 if (bb->shift > 0) {
339 /* When clearing we round the start up and the end down.
340 * This should not matter as the shift should align with
341 * the block size and no rounding should ever be needed.
342 * However it is better the think a block is bad when it
343 * isn't than to think a block is not bad when it is.
344 */
345 s += (1<<bb->shift) - 1;
346 s >>= bb->shift;
347 target >>= bb->shift;
348 sectors = target - s;
349 }
350
351 write_seqlock_irq(&bb->lock);
352
353 p = bb->page;
354 lo = 0;
355 hi = bb->count;
356 /* Find the last range that starts before 'target' */
357 while (hi - lo > 1) {
358 int mid = (lo + hi) / 2;
359 sector_t a = BB_OFFSET(p[mid]);
360
361 if (a < target)
362 lo = mid;
363 else
364 hi = mid;
365 }
366 if (hi > lo) {
367 /* p[lo] is the last range that could overlap the
368 * current range. Earlier ranges could also overlap,
369 * but only this one can overlap the end of the range.
370 */
371 if ((BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > target) &&
372 (BB_OFFSET(p[lo]) < target)) {
373 /* Partial overlap, leave the tail of this range */
374 int ack = BB_ACK(p[lo]);
375 sector_t a = BB_OFFSET(p[lo]);
376 sector_t end = a + BB_LEN(p[lo]);
377
378 if (a < s) {
379 /* we need to split this range */
380 if (bb->count >= MAX_BADBLOCKS) {
381 rv = -ENOSPC;
382 goto out;
383 }
384 memmove(p+lo+1, p+lo, (bb->count - lo) * 8);
385 bb->count++;
386 p[lo] = BB_MAKE(a, s-a, ack);
387 lo++;
388 }
389 p[lo] = BB_MAKE(target, end - target, ack);
390 /* there is no longer an overlap */
391 hi = lo;
392 lo--;
393 }
394 while (lo >= 0 &&
395 (BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) &&
396 (BB_OFFSET(p[lo]) < target)) {
397 /* This range does overlap */
398 if (BB_OFFSET(p[lo]) < s) {
399 /* Keep the early parts of this range. */
400 int ack = BB_ACK(p[lo]);
401 sector_t start = BB_OFFSET(p[lo]);
402
403 p[lo] = BB_MAKE(start, s - start, ack);
404 /* now low doesn't overlap, so.. */
405 break;
406 }
407 lo--;
408 }
409 /* 'lo' is strictly before, 'hi' is strictly after,
410 * anything between needs to be discarded
411 */
412 if (hi - lo > 1) {
413 memmove(p+lo+1, p+hi, (bb->count - hi) * 8);
414 bb->count -= (hi - lo - 1);
415 }
416 }
417
418 badblocks_update_acked(bb);
419 bb->changed = 1;
420out:
421 write_sequnlock_irq(&bb->lock);
422 return rv;
423}
424EXPORT_SYMBOL_GPL(badblocks_clear);
425
426/**
427 * ack_all_badblocks() - Acknowledge all bad blocks in a list.
428 * @bb: the badblocks structure that holds all badblock information
429 *
430 * This only succeeds if ->changed is clear. It is used by
431 * in-kernel metadata updates
432 */
433void ack_all_badblocks(struct badblocks *bb)
434{
435 if (bb->page == NULL || bb->changed)
436 /* no point even trying */
437 return;
438 write_seqlock_irq(&bb->lock);
439
440 if (bb->changed == 0 && bb->unacked_exist) {
441 u64 *p = bb->page;
442 int i;
443
444 for (i = 0; i < bb->count ; i++) {
445 if (!BB_ACK(p[i])) {
446 sector_t start = BB_OFFSET(p[i]);
447 int len = BB_LEN(p[i]);
448
449 p[i] = BB_MAKE(start, len, 1);
450 }
451 }
452 bb->unacked_exist = 0;
453 }
454 write_sequnlock_irq(&bb->lock);
455}
456EXPORT_SYMBOL_GPL(ack_all_badblocks);
457
458/**
459 * badblocks_show() - sysfs access to bad-blocks list
460 * @bb: the badblocks structure that holds all badblock information
461 * @page: buffer received from sysfs
462 * @unack: weather to show unacknowledged badblocks
463 *
464 * Return:
465 * Length of returned data
466 */
467ssize_t badblocks_show(struct badblocks *bb, char *page, int unack)
468{
469 size_t len;
470 int i;
471 u64 *p = bb->page;
472 unsigned seq;
473
474 if (bb->shift < 0)
475 return 0;
476
477retry:
478 seq = read_seqbegin(&bb->lock);
479
480 len = 0;
481 i = 0;
482
483 while (len < PAGE_SIZE && i < bb->count) {
484 sector_t s = BB_OFFSET(p[i]);
485 unsigned int length = BB_LEN(p[i]);
486 int ack = BB_ACK(p[i]);
487
488 i++;
489
490 if (unack && ack)
491 continue;
492
493 len += snprintf(page+len, PAGE_SIZE-len, "%llu %u\n",
494 (unsigned long long)s << bb->shift,
495 length << bb->shift);
496 }
497 if (unack && len == 0)
498 bb->unacked_exist = 0;
499
500 if (read_seqretry(&bb->lock, seq))
501 goto retry;
502
503 return len;
504}
505EXPORT_SYMBOL_GPL(badblocks_show);
506
507/**
508 * badblocks_store() - sysfs access to bad-blocks list
509 * @bb: the badblocks structure that holds all badblock information
510 * @page: buffer received from sysfs
511 * @len: length of data received from sysfs
512 * @unack: weather to show unacknowledged badblocks
513 *
514 * Return:
515 * Length of the buffer processed or -ve error.
516 */
517ssize_t badblocks_store(struct badblocks *bb, const char *page, size_t len,
518 int unack)
519{
520 unsigned long long sector;
521 int length;
522 char newline;
523
524 switch (sscanf(page, "%llu %d%c", §or, &length, &newline)) {
525 case 3:
526 if (newline != '\n')
527 return -EINVAL;
528 fallthrough;
529 case 2:
530 if (length <= 0)
531 return -EINVAL;
532 break;
533 default:
534 return -EINVAL;
535 }
536
537 if (badblocks_set(bb, sector, length, !unack))
538 return -ENOSPC;
539 else
540 return len;
541}
542EXPORT_SYMBOL_GPL(badblocks_store);
543
544static int __badblocks_init(struct device *dev, struct badblocks *bb,
545 int enable)
546{
547 bb->dev = dev;
548 bb->count = 0;
549 if (enable)
550 bb->shift = 0;
551 else
552 bb->shift = -1;
553 if (dev)
554 bb->page = devm_kzalloc(dev, PAGE_SIZE, GFP_KERNEL);
555 else
556 bb->page = kzalloc(PAGE_SIZE, GFP_KERNEL);
557 if (!bb->page) {
558 bb->shift = -1;
559 return -ENOMEM;
560 }
561 seqlock_init(&bb->lock);
562
563 return 0;
564}
565
566/**
567 * badblocks_init() - initialize the badblocks structure
568 * @bb: the badblocks structure that holds all badblock information
569 * @enable: weather to enable badblocks accounting
570 *
571 * Return:
572 * 0: success
573 * -ve errno: on error
574 */
575int badblocks_init(struct badblocks *bb, int enable)
576{
577 return __badblocks_init(NULL, bb, enable);
578}
579EXPORT_SYMBOL_GPL(badblocks_init);
580
581int devm_init_badblocks(struct device *dev, struct badblocks *bb)
582{
583 if (!bb)
584 return -EINVAL;
585 return __badblocks_init(dev, bb, 1);
586}
587EXPORT_SYMBOL_GPL(devm_init_badblocks);
588
589/**
590 * badblocks_exit() - free the badblocks structure
591 * @bb: the badblocks structure that holds all badblock information
592 */
593void badblocks_exit(struct badblocks *bb)
594{
595 if (!bb)
596 return;
597 if (bb->dev)
598 devm_kfree(bb->dev, bb->page);
599 else
600 kfree(bb->page);
601 bb->page = NULL;
602}
603EXPORT_SYMBOL_GPL(badblocks_exit);