[linux-2.6-block.git] / block / badblocks.c

/*
 * Bad block management
 *
 * - Heavily based on MD badblocks code from Neil Brown
 *
 * Copyright (c) 2015, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 */

#include <linux/badblocks.h>
#include <linux/seqlock.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/stddef.h>
#include <linux/types.h>
#include <linux/slab.h>

/**
 * badblocks_check() - check a given range for bad sectors
 * @bb:		the badblocks structure that holds all badblock information
 * @s:		sector (start) at which to check for badblocks
 * @sectors:	number of sectors to check for badblocks
 * @first_bad:	pointer to store location of the first badblock
 * @bad_sectors: pointer to store number of badblocks after @first_bad
 *
 * We can record which blocks on each device are 'bad' and so just
 * fail those blocks, or that stripe, rather than the whole device.
 * Entries in the bad-block table are 64bits wide.  This comprises:
 * Length of bad-range, in sectors: 0-511 for lengths 1-512
 * Start of bad-range, sector offset, 54 bits (allows 8 exbibytes)
 *  A 'shift' can be set so that larger blocks are tracked and
 *  consequently larger devices can be covered.
 * 'Acknowledged' flag - 1 bit. - the most significant bit.
 *
 * Locking of the bad-block table uses a seqlock so badblocks_check
 * might need to retry if it is very unlucky.
 * We will sometimes want to check for bad blocks in a bi_end_io function,
 * so we use the write_seqlock_irq variant.
 *
 * When looking for a bad block we specify a range and want to
 * know if any block in the range is bad.  So we binary-search
 * to the last range that starts at-or-before the given endpoint,
 * (or "before the sector after the target range")
 * then see if it ends after the given start.
 *
 * Return:
 *  0: there are no known bad blocks in the range
 *  1: there are known bad block which are all acknowledged
 * -1: there are bad blocks which have not yet been acknowledged in metadata.
 * plus the start/length of the first bad section we overlap.
 */
int badblocks_check(struct badblocks *bb, sector_t s, int sectors,
			sector_t *first_bad, int *bad_sectors)
{
	int hi;
	int lo;
	u64 *p = bb->page;
	int rv;
	sector_t target = s + sectors;
	unsigned seq;

	if (bb->shift > 0) {
		/* round the start down, and the end up */
		s >>= bb->shift;
		target += (1<<bb->shift) - 1;
		target >>= bb->shift;
		sectors = target - s;
	}
	/* 'target' is now the first block after the bad range */

retry:
	seq = read_seqbegin(&bb->lock);
	lo = 0;
	rv = 0;
	hi = bb->count;

	/* Binary search between lo and hi for 'target'
	 * i.e. for the last range that starts before 'target'
	 */
	/* INVARIANT: ranges before 'lo' and at-or-after 'hi'
	 * are known not to be the last range before target.
	 * VARIANT: hi-lo is the number of possible
	 * ranges, and decreases until it reaches 1
	 */
	while (hi - lo > 1) {
		int mid = (lo + hi) / 2;
		sector_t a = BB_OFFSET(p[mid]);

		if (a < target)
			/* This could still be the one, earlier ranges
			 * could not.
			 */
			lo = mid;
		else
			/* This and later ranges are definitely out. */
			hi = mid;
	}
	/* 'lo' might be the last that started before target, but 'hi' isn't */
	if (hi > lo) {
		/* need to check all range that end after 's' to see if
		 * any are unacknowledged.
		 */
		while (lo >= 0 &&
		       BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) {
			if (BB_OFFSET(p[lo]) < target) {
				/* starts before the end, and finishes after
				 * the start, so they must overlap
				 */
				if (rv != -1 && BB_ACK(p[lo]))
					rv = 1;
				else
					rv = -1;
				*first_bad = BB_OFFSET(p[lo]);
				*bad_sectors = BB_LEN(p[lo]);
			}
			lo--;
		}
	}

	if (read_seqretry(&bb->lock, seq))
		goto retry;

	return rv;
}
EXPORT_SYMBOL_GPL(badblocks_check);

/**
 * badblocks_set() - Add a range of bad blocks to the table.
 * @bb:		the badblocks structure that holds all badblock information
 * @s:		first sector to mark as bad
 * @sectors:	number of sectors to mark as bad
 * @acknowledged: weather to mark the bad sectors as acknowledged
 *
 * This might extend the table, or might contract it if two adjacent ranges
 * can be merged. We binary-search to find the 'insertion' point, then
 * decide how best to handle it.
 *
 * Return:
 *  0: success
 *  1: failed to set badblocks (out of space)
 */
int badblocks_set(struct badblocks *bb, sector_t s, int sectors,
			int acknowledged)
{
	u64 *p;
	int lo, hi;
	int rv = 0;
	unsigned long flags;

	if (bb->shift < 0)
		/* badblocks are disabled */
		return 0;

	if (bb->shift) {
		/* round the start down, and the end up */
		sector_t next = s + sectors;

		s >>= bb->shift;
		next += (1<<bb->shift) - 1;
		next >>= bb->shift;
		sectors = next - s;
	}

	write_seqlock_irqsave(&bb->lock, flags);

	p = bb->page;
	lo = 0;
	hi = bb->count;
	/* Find the last range that starts at-or-before 's' */
	while (hi - lo > 1) {
		int mid = (lo + hi) / 2;
		sector_t a = BB_OFFSET(p[mid]);

		if (a <= s)
			lo = mid;
		else
			hi = mid;
	}
	if (hi > lo && BB_OFFSET(p[lo]) > s)
		hi = lo;

	if (hi > lo) {
		/* we found a range that might merge with the start
		 * of our new range
		 */
		sector_t a = BB_OFFSET(p[lo]);
		sector_t e = a + BB_LEN(p[lo]);
		int ack = BB_ACK(p[lo]);

		if (e >= s) {
			/* Yes, we can merge with a previous range */
			if (s == a && s + sectors >= e)
				/* new range covers old */
				ack = acknowledged;
			else
				ack = ack && acknowledged;

			if (e < s + sectors)
				e = s + sectors;
			if (e - a <= BB_MAX_LEN) {
				p[lo] = BB_MAKE(a, e-a, ack);
				s = e;
			} else {
				/* does not all fit in one range,
				 * make p[lo] maximal
				 */
				if (BB_LEN(p[lo]) != BB_MAX_LEN)
					p[lo] = BB_MAKE(a, BB_MAX_LEN, ack);
				s = a + BB_MAX_LEN;
			}
			sectors = e - s;
		}
	}
	if (sectors && hi < bb->count) {
		/* 'hi' points to the first range that starts after 's'.
		 * Maybe we can merge with the start of that range
		 */
		sector_t a = BB_OFFSET(p[hi]);
		sector_t e = a + BB_LEN(p[hi]);
		int ack = BB_ACK(p[hi]);

		if (a <= s + sectors) {
			/* merging is possible */
			if (e <= s + sectors) {
				/* full overlap */
				e = s + sectors;
				ack = acknowledged;
			} else
				ack = ack && acknowledged;

			a = s;
			if (e - a <= BB_MAX_LEN) {
				p[hi] = BB_MAKE(a, e-a, ack);
				s = e;
			} else {
				p[hi] = BB_MAKE(a, BB_MAX_LEN, ack);
				s = a + BB_MAX_LEN;
			}
			sectors = e - s;
			lo = hi;
			hi++;
		}
	}
	if (sectors == 0 && hi < bb->count) {
		/* we might be able to combine lo and hi */
		/* Note: 's' is at the end of 'lo' */
		sector_t a = BB_OFFSET(p[hi]);
		int lolen = BB_LEN(p[lo]);
		int hilen = BB_LEN(p[hi]);
		int newlen = lolen + hilen - (s - a);

		if (s >= a && newlen < BB_MAX_LEN) {
			/* yes, we can combine them */
			int ack = BB_ACK(p[lo]) && BB_ACK(p[hi]);

			p[lo] = BB_MAKE(BB_OFFSET(p[lo]), newlen, ack);
			memmove(p + hi, p + hi + 1,
				(bb->count - hi - 1) * 8);
			bb->count--;
		}
	}
	while (sectors) {
		/* didn't merge (it all).
		 * Need to add a range just before 'hi'
		 */
		if (bb->count >= MAX_BADBLOCKS) {
			/* No room for more */
			rv = 1;
			break;
		} else {
			int this_sectors = sectors;

			memmove(p + hi + 1, p + hi,
				(bb->count - hi) * 8);
			bb->count++;

			if (this_sectors > BB_MAX_LEN)
				this_sectors = BB_MAX_LEN;
			p[hi] = BB_MAKE(s, this_sectors, acknowledged);
			sectors -= this_sectors;
			s += this_sectors;
		}
	}

	bb->changed = 1;
	if (!acknowledged)
		bb->unacked_exist = 1;
	write_sequnlock_irqrestore(&bb->lock, flags);

	return rv;
}
EXPORT_SYMBOL_GPL(badblocks_set);

/**
 * badblocks_clear() - Remove a range of bad blocks to the table.
 * @bb:		the badblocks structure that holds all badblock information
 * @s:		first sector to mark as bad
 * @sectors:	number of sectors to mark as bad
 *
 * This may involve extending the table if we spilt a region,
 * but it must not fail.  So if the table becomes full, we just
 * drop the remove request.
 *
 * Return:
 *  0: success
 *  1: failed to clear badblocks
 */
int badblocks_clear(struct badblocks *bb, sector_t s, int sectors)
{
	u64 *p;
	int lo, hi;
	sector_t target = s + sectors;
	int rv = 0;

	if (bb->shift > 0) {
		/* When clearing we round the start up and the end down.
		 * This should not matter as the shift should align with
		 * the block size and no rounding should ever be needed.
		 * However it is better the think a block is bad when it
		 * isn't than to think a block is not bad when it is.
		 */
		s += (1<<bb->shift) - 1;
		s >>= bb->shift;
		target >>= bb->shift;
		sectors = target - s;
	}

	write_seqlock_irq(&bb->lock);

	p = bb->page;
	lo = 0;
	hi = bb->count;
	/* Find the last range that starts before 'target' */
	while (hi - lo > 1) {
		int mid = (lo + hi) / 2;
		sector_t a = BB_OFFSET(p[mid]);

		if (a < target)
			lo = mid;
		else
			hi = mid;
	}
	if (hi > lo) {
		/* p[lo] is the last range that could overlap the
		 * current range.  Earlier ranges could also overlap,
		 * but only this one can overlap the end of the range.
		 */
		if (BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > target) {
			/* Partial overlap, leave the tail of this range */
			int ack = BB_ACK(p[lo]);
			sector_t a = BB_OFFSET(p[lo]);
			sector_t end = a + BB_LEN(p[lo]);

			if (a < s) {
				/* we need to split this range */
				if (bb->count >= MAX_BADBLOCKS) {
					rv = -ENOSPC;
					goto out;
				}
				memmove(p+lo+1, p+lo, (bb->count - lo) * 8);
				bb->count++;
				p[lo] = BB_MAKE(a, s-a, ack);
				lo++;
			}
			p[lo] = BB_MAKE(target, end - target, ack);
			/* there is no longer an overlap */
			hi = lo;
			lo--;
		}
		while (lo >= 0 &&
		       BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) {
			/* This range does overlap */
			if (BB_OFFSET(p[lo]) < s) {
				/* Keep the early parts of this range. */
				int ack = BB_ACK(p[lo]);
				sector_t start = BB_OFFSET(p[lo]);

				p[lo] = BB_MAKE(start, s - start, ack);
				/* now low doesn't overlap, so.. */
				break;
			}
			lo--;
		}
		/* 'lo' is strictly before, 'hi' is strictly after,
		 * anything between needs to be discarded
		 */
		if (hi - lo > 1) {
			memmove(p+lo+1, p+hi, (bb->count - hi) * 8);
			bb->count -= (hi - lo - 1);
		}
	}

	bb->changed = 1;
out:
	write_sequnlock_irq(&bb->lock);
	return rv;
}
EXPORT_SYMBOL_GPL(badblocks_clear);

/**
 * ack_all_badblocks() - Acknowledge all bad blocks in a list.
 * @bb:		the badblocks structure that holds all badblock information
 *
 * This only succeeds if ->changed is clear.  It is used by
 * in-kernel metadata updates
 */
void ack_all_badblocks(struct badblocks *bb)
{
	if (bb->page == NULL || bb->changed)
		/* no point even trying */
		return;
	write_seqlock_irq(&bb->lock);

	if (bb->changed == 0 && bb->unacked_exist) {
		u64 *p = bb->page;
		int i;

		for (i = 0; i < bb->count ; i++) {
			if (!BB_ACK(p[i])) {
				sector_t start = BB_OFFSET(p[i]);
				int len = BB_LEN(p[i]);

				p[i] = BB_MAKE(start, len, 1);
			}
		}
		bb->unacked_exist = 0;
	}
	write_sequnlock_irq(&bb->lock);
}
EXPORT_SYMBOL_GPL(ack_all_badblocks);

/**
 * badblocks_show() - sysfs access to bad-blocks list
 * @bb:		the badblocks structure that holds all badblock information
 * @page:	buffer received from sysfs
 * @unack:	weather to show unacknowledged badblocks
 *
 * Return:
 *  Length of returned data
 */
ssize_t badblocks_show(struct badblocks *bb, char *page, int unack)
{
	size_t len;
	int i;
	u64 *p = bb->page;
	unsigned seq;

	if (bb->shift < 0)
		return 0;

retry:
	seq = read_seqbegin(&bb->lock);

	len = 0;
	i = 0;

	while (len < PAGE_SIZE && i < bb->count) {
		sector_t s = BB_OFFSET(p[i]);
		unsigned int length = BB_LEN(p[i]);
		int ack = BB_ACK(p[i]);

		i++;

		if (unack && ack)
			continue;

		len += snprintf(page+len, PAGE_SIZE-len, "%llu %u\n",
				(unsigned long long)s << bb->shift,
				length << bb->shift);
	}
	if (unack && len == 0)
		bb->unacked_exist = 0;

	if (read_seqretry(&bb->lock, seq))
		goto retry;

	return len;
}
EXPORT_SYMBOL_GPL(badblocks_show);

/**
 * badblocks_store() - sysfs access to bad-blocks list
 * @bb:		the badblocks structure that holds all badblock information
 * @page:	buffer received from sysfs
 * @len:	length of data received from sysfs
 * @unack:	weather to show unacknowledged badblocks
 *
 * Return:
 *  Length of the buffer processed or -ve error.
 */
ssize_t badblocks_store(struct badblocks *bb, const char *page, size_t len,
			int unack)
{
	unsigned long long sector;
	int length;
	char newline;

	switch (sscanf(page, "%llu %d%c", &sector, &length, &newline)) {
	case 3:
		if (newline != '\n')
			return -EINVAL;
	case 2:
		if (length <= 0)
			return -EINVAL;
		break;
	default:
		return -EINVAL;
	}

	if (badblocks_set(bb, sector, length, !unack))
		return -ENOSPC;
	else
		return len;
}
EXPORT_SYMBOL_GPL(badblocks_store);

static int __badblocks_init(struct device *dev, struct badblocks *bb,
		int enable)
{
	bb->dev = dev;
	bb->count = 0;
	if (enable)
		bb->shift = 0;
	else
		bb->shift = -1;
	if (dev)
		bb->page = devm_kzalloc(dev, PAGE_SIZE, GFP_KERNEL);
	else
		bb->page = kzalloc(PAGE_SIZE, GFP_KERNEL);
	if (!bb->page) {
		bb->shift = -1;
		return -ENOMEM;
	}
	seqlock_init(&bb->lock);

	return 0;
}

/**
 * badblocks_init() - initialize the badblocks structure
 * @bb:		the badblocks structure that holds all badblock information
 * @enable:	weather to enable badblocks accounting
 *
 * Return:
 *  0: success
 *  -ve errno: on error
 */
int badblocks_init(struct badblocks *bb, int enable)
{
	return __badblocks_init(NULL, bb, enable);
}
EXPORT_SYMBOL_GPL(badblocks_init);

int devm_init_badblocks(struct device *dev, struct badblocks *bb)
{
	if (!bb)
		return -EINVAL;
	return __badblocks_init(dev, bb, 1);
}
EXPORT_SYMBOL_GPL(devm_init_badblocks);

/**
 * badblocks_exit() - free the badblocks structure
 * @bb:		the badblocks structure that holds all badblock information
 */
void badblocks_exit(struct badblocks *bb)
{
	if (!bb)
		return;
	if (bb->dev)
		devm_kfree(bb->dev, bb->page);
	else
		kfree(bb->page);
	bb->page = NULL;
}
EXPORT_SYMBOL_GPL(badblocks_exit);
Commit	Line	Data
9e0e252a VV	1	/*
	2	* Bad block management
	3	*
	4	* - Heavily based on MD badblocks code from Neil Brown
	5	*
	6	* Copyright (c) 2015, Intel Corporation.
	7	*
	8	* This program is free software; you can redistribute it and/or modify it
	9	* under the terms and conditions of the GNU General Public License,
	10	* version 2, as published by the Free Software Foundation.
	11	*
	12	* This program is distributed in the hope it will be useful, but WITHOUT
	13	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	14	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	15	* more details.
	16	*/
	17
	18	#include <linux/badblocks.h>
	19	#include <linux/seqlock.h>
16263ff6	20	#include <linux/device.h>
9e0e252a VV	21	#include <linux/kernel.h>
	22	#include <linux/module.h>
	23	#include <linux/stddef.h>
	24	#include <linux/types.h>
	25	#include <linux/slab.h>
	26
	27	/**
	28	* badblocks_check() - check a given range for bad sectors
	29	* @bb: the badblocks structure that holds all badblock information
	30	* @s: sector (start) at which to check for badblocks
	31	* @sectors: number of sectors to check for badblocks
	32	* @first_bad: pointer to store location of the first badblock
	33	* @bad_sectors: pointer to store number of badblocks after @first_bad
	34	*
	35	* We can record which blocks on each device are 'bad' and so just
	36	* fail those blocks, or that stripe, rather than the whole device.
	37	* Entries in the bad-block table are 64bits wide. This comprises:
	38	* Length of bad-range, in sectors: 0-511 for lengths 1-512
	39	* Start of bad-range, sector offset, 54 bits (allows 8 exbibytes)
	40	* A 'shift' can be set so that larger blocks are tracked and
	41	* consequently larger devices can be covered.
	42	* 'Acknowledged' flag - 1 bit. - the most significant bit.
	43	*
	44	* Locking of the bad-block table uses a seqlock so badblocks_check
	45	* might need to retry if it is very unlucky.
	46	* We will sometimes want to check for bad blocks in a bi_end_io function,
	47	* so we use the write_seqlock_irq variant.
	48	*
	49	* When looking for a bad block we specify a range and want to
	50	* know if any block in the range is bad. So we binary-search
	51	* to the last range that starts at-or-before the given endpoint,
	52	* (or "before the sector after the target range")
	53	* then see if it ends after the given start.
	54	*
	55	* Return:
	56	* 0: there are no known bad blocks in the range
	57	* 1: there are known bad block which are all acknowledged
	58	* -1: there are bad blocks which have not yet been acknowledged in metadata.
	59	* plus the start/length of the first bad section we overlap.
	60	*/
	61	int badblocks_check(struct badblocks *bb, sector_t s, int sectors,
	62	sector_t first_bad, int bad_sectors)
	63	{
	64	int hi;
	65	int lo;
	66	u64 *p = bb->page;
	67	int rv;
	68	sector_t target = s + sectors;
	69	unsigned seq;
	70
	71	if (bb->shift > 0) {
	72	/* round the start down, and the end up */
	73	s >>= bb->shift;
	74	target += (1<<bb->shift) - 1;
	75	target >>= bb->shift;
	76	sectors = target - s;
	77	}
	78	/* 'target' is now the first block after the bad range */
	79
	80	retry:
	81	seq = read_seqbegin(&bb->lock);
	82	lo = 0;
	83	rv = 0;
	84	hi = bb->count;
85
86	/* Binary search between lo and hi for 'target'
87	* i.e. for the last range that starts before 'target'
88	*/
89	/* INVARIANT: ranges before 'lo' and at-or-after 'hi'
90	* are known not to be the last range before target.
91	* VARIANT: hi-lo is the number of possible
92	* ranges, and decreases until it reaches 1
93	*/
94	while (hi - lo > 1) {
95	int mid = (lo + hi) / 2;
96	sector_t a = BB_OFFSET(p[mid]);
97
98	if (a < target)
99	/* This could still be the one, earlier ranges
100	* could not.
101	*/
102	lo = mid;
103	else
104	/* This and later ranges are definitely out. */
105	hi = mid;
106	}
107	/* 'lo' might be the last that started before target, but 'hi' isn't */
108	if (hi > lo) {
109	/* need to check all range that end after 's' to see if
110	* any are unacknowledged.
111	*/
112	while (lo >= 0 &&
113	BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) {
114	if (BB_OFFSET(p[lo]) < target) {
115	/* starts before the end, and finishes after
116	* the start, so they must overlap
117	*/
118	if (rv != -1 && BB_ACK(p[lo]))
119	rv = 1;
120	else
121	rv = -1;
122	*first_bad = BB_OFFSET(p[lo]);
123	*bad_sectors = BB_LEN(p[lo]);
124	}
125	lo--;
126	}
127	}
128
129	if (read_seqretry(&bb->lock, seq))
130	goto retry;
131
132	return rv;
133	}
134	EXPORT_SYMBOL_GPL(badblocks_check);
135
136	/**
137	* badblocks_set() - Add a range of bad blocks to the table.
138	* @bb: the badblocks structure that holds all badblock information
139	* @s: first sector to mark as bad
140	* @sectors: number of sectors to mark as bad
141	* @acknowledged: weather to mark the bad sectors as acknowledged
142	*
143	* This might extend the table, or might contract it if two adjacent ranges
144	* can be merged. We binary-search to find the 'insertion' point, then
145	* decide how best to handle it.
146	*
147	* Return:
148	* 0: success
149	* 1: failed to set badblocks (out of space)
150	*/
151	int badblocks_set(struct badblocks *bb, sector_t s, int sectors,
152	int acknowledged)
153	{
154	u64 *p;
155	int lo, hi;
156	int rv = 0;
157	unsigned long flags;
158
159	if (bb->shift < 0)
160	/* badblocks are disabled */
161	return 0;
162
163	if (bb->shift) {
164	/* round the start down, and the end up */
165	sector_t next = s + sectors;
166
167	s >>= bb->shift;
168	next += (1<<bb->shift) - 1;
169	next >>= bb->shift;
170	sectors = next - s;
171	}
172
173	write_seqlock_irqsave(&bb->lock, flags);
174
175	p = bb->page;
176	lo = 0;
177	hi = bb->count;
178	/* Find the last range that starts at-or-before 's' */
179	while (hi - lo > 1) {
180	int mid = (lo + hi) / 2;
181	sector_t a = BB_OFFSET(p[mid]);
182
183	if (a <= s)
184	lo = mid;
185	else
186	hi = mid;
187	}
188	if (hi > lo && BB_OFFSET(p[lo]) > s)
189	hi = lo;
190
191	if (hi > lo) {
192	/* we found a range that might merge with the start
193	* of our new range
194	*/
195	sector_t a = BB_OFFSET(p[lo]);
196	sector_t e = a + BB_LEN(p[lo]);
197	int ack = BB_ACK(p[lo]);
198
199	if (e >= s) {
200	/* Yes, we can merge with a previous range */
201	if (s == a && s + sectors >= e)
202	/* new range covers old */
203	ack = acknowledged;
204	else
205	ack = ack && acknowledged;
206
207	if (e < s + sectors)
208	e = s + sectors;
209	if (e - a <= BB_MAX_LEN) {
210	p[lo] = BB_MAKE(a, e-a, ack);
211	s = e;
212	} else {
213	/* does not all fit in one range,
214	* make p[lo] maximal
215	*/
216	if (BB_LEN(p[lo]) != BB_MAX_LEN)
217	p[lo] = BB_MAKE(a, BB_MAX_LEN, ack);
218	s = a + BB_MAX_LEN;
219	}
220	sectors = e - s;
221	}
222	}
223	if (sectors && hi < bb->count) {
224	/* 'hi' points to the first range that starts after 's'.
225	* Maybe we can merge with the start of that range
226	*/
227	sector_t a = BB_OFFSET(p[hi]);
228	sector_t e = a + BB_LEN(p[hi]);
229	int ack = BB_ACK(p[hi]);
230
231	if (a <= s + sectors) {
232	/* merging is possible */
233	if (e <= s + sectors) {
234	/* full overlap */
235	e = s + sectors;
236	ack = acknowledged;
237	} else
238	ack = ack && acknowledged;
239
240	a = s;
241	if (e - a <= BB_MAX_LEN) {
242	p[hi] = BB_MAKE(a, e-a, ack);
243	s = e;
244	} else {
245	p[hi] = BB_MAKE(a, BB_MAX_LEN, ack);
246	s = a + BB_MAX_LEN;
247	}
248	sectors = e - s;
249	lo = hi;
250	hi++;
251	}
252	}
253	if (sectors == 0 && hi < bb->count) {
254	/* we might be able to combine lo and hi */
255	/* Note: 's' is at the end of 'lo' */
256	sector_t a = BB_OFFSET(p[hi]);
257	int lolen = BB_LEN(p[lo]);
258	int hilen = BB_LEN(p[hi]);
259	int newlen = lolen + hilen - (s - a);
260
261	if (s >= a && newlen < BB_MAX_LEN) {
262	/* yes, we can combine them */
263	int ack = BB_ACK(p[lo]) && BB_ACK(p[hi]);
264
265	p[lo] = BB_MAKE(BB_OFFSET(p[lo]), newlen, ack);
266	memmove(p + hi, p + hi + 1,
267	(bb->count - hi - 1) * 8);
268	bb->count--;
269	}
270	}
271	while (sectors) {
272	/* didn't merge (it all).
273	* Need to add a range just before 'hi'
274	*/
275	if (bb->count >= MAX_BADBLOCKS) {
276	/* No room for more */
277	rv = 1;
278	break;
279	} else {
280	int this_sectors = sectors;
281
282	memmove(p + hi + 1, p + hi,
283	(bb->count - hi) * 8);
284	bb->count++;
285
286	if (this_sectors > BB_MAX_LEN)
287	this_sectors = BB_MAX_LEN;
288	p[hi] = BB_MAKE(s, this_sectors, acknowledged);
289	sectors -= this_sectors;
290	s += this_sectors;
291	}
292	}
293
294	bb->changed = 1;
295	if (!acknowledged)
296	bb->unacked_exist = 1;
297	write_sequnlock_irqrestore(&bb->lock, flags);
298
299	return rv;
300	}
301	EXPORT_SYMBOL_GPL(badblocks_set);
302
303	/**
304	* badblocks_clear() - Remove a range of bad blocks to the table.
305	* @bb: the badblocks structure that holds all badblock information
306	* @s: first sector to mark as bad
307	* @sectors: number of sectors to mark as bad
308	*
309	* This may involve extending the table if we spilt a region,
310	* but it must not fail. So if the table becomes full, we just
311	* drop the remove request.
312	*
313	* Return:
314	* 0: success
315	* 1: failed to clear badblocks
316	*/
317	int badblocks_clear(struct badblocks *bb, sector_t s, int sectors)
318	{
319	u64 *p;
320	int lo, hi;
321	sector_t target = s + sectors;
322	int rv = 0;
323
324	if (bb->shift > 0) {
325	/* When clearing we round the start up and the end down.
326	* This should not matter as the shift should align with
327	* the block size and no rounding should ever be needed.
328	* However it is better the think a block is bad when it
329	* isn't than to think a block is not bad when it is.
330	*/
331	s += (1<<bb->shift) - 1;
332	s >>= bb->shift;
333	target >>= bb->shift;
334	sectors = target - s;
335	}
336
337	write_seqlock_irq(&bb->lock);
338
339	p = bb->page;
340	lo = 0;
341	hi = bb->count;
342	/* Find the last range that starts before 'target' */
343	while (hi - lo > 1) {
344	int mid = (lo + hi) / 2;
345	sector_t a = BB_OFFSET(p[mid]);
346
347	if (a < target)
348	lo = mid;
349	else
350	hi = mid;
351	}
352	if (hi > lo) {
353	/* p[lo] is the last range that could overlap the
354	* current range. Earlier ranges could also overlap,
355	* but only this one can overlap the end of the range.
356	*/
357	if (BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > target) {
358	/* Partial overlap, leave the tail of this range */
359	int ack = BB_ACK(p[lo]);
360	sector_t a = BB_OFFSET(p[lo]);
361	sector_t end = a + BB_LEN(p[lo]);
362
363	if (a < s) {
364	/* we need to split this range */
365	if (bb->count >= MAX_BADBLOCKS) {
366	rv = -ENOSPC;
367	goto out;
368	}
369	memmove(p+lo+1, p+lo, (bb->count - lo) * 8);
370	bb->count++;
371	p[lo] = BB_MAKE(a, s-a, ack);
372	lo++;
373	}
374	p[lo] = BB_MAKE(target, end - target, ack);
375	/* there is no longer an overlap */
376	hi = lo;
377	lo--;
378	}
379	while (lo >= 0 &&
380	BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) {
381	/* This range does overlap */
382	if (BB_OFFSET(p[lo]) < s) {
383	/* Keep the early parts of this range. */
384	int ack = BB_ACK(p[lo]);
385	sector_t start = BB_OFFSET(p[lo]);
386
387	p[lo] = BB_MAKE(start, s - start, ack);
388	/* now low doesn't overlap, so.. */
389	break;
390	}
391	lo--;
392	}
393	/* 'lo' is strictly before, 'hi' is strictly after,
394	* anything between needs to be discarded
395	*/
396	if (hi - lo > 1) {
397	memmove(p+lo+1, p+hi, (bb->count - hi) * 8);
398	bb->count -= (hi - lo - 1);
399	}
400	}
401
402	bb->changed = 1;
403	out:
404	write_sequnlock_irq(&bb->lock);
405	return rv;
406	}
407	EXPORT_SYMBOL_GPL(badblocks_clear);
408
409	/**
410	* ack_all_badblocks() - Acknowledge all bad blocks in a list.
411	* @bb: the badblocks structure that holds all badblock information
412	*
413	* This only succeeds if ->changed is clear. It is used by
414	* in-kernel metadata updates
415	*/
416	void ack_all_badblocks(struct badblocks *bb)
417	{
418	if (bb->page == NULL \|\| bb->changed)
419	/* no point even trying */
420	return;
421	write_seqlock_irq(&bb->lock);
422
423	if (bb->changed == 0 && bb->unacked_exist) {
424	u64 *p = bb->page;
425	int i;
426
427	for (i = 0; i < bb->count ; i++) {
428	if (!BB_ACK(p[i])) {
429	sector_t start = BB_OFFSET(p[i]);
430	int len = BB_LEN(p[i]);
431
432	p[i] = BB_MAKE(start, len, 1);
433	}
434	}
435	bb->unacked_exist = 0;
436	}
437	write_sequnlock_irq(&bb->lock);
438	}
439	EXPORT_SYMBOL_GPL(ack_all_badblocks);
440
441	/**
442	* badblocks_show() - sysfs access to bad-blocks list
443	* @bb: the badblocks structure that holds all badblock information
444	* @page: buffer received from sysfs
445	* @unack: weather to show unacknowledged badblocks
446	*
447	* Return:
448	* Length of returned data
449	*/
450	ssize_t badblocks_show(struct badblocks bb, char page, int unack)
451	{
452	size_t len;
453	int i;
454	u64 *p = bb->page;
455	unsigned seq;
456
457	if (bb->shift < 0)
458	return 0;
459
460	retry:
461	seq = read_seqbegin(&bb->lock);
462
463	len = 0;
464	i = 0;
465
466	while (len < PAGE_SIZE && i < bb->count) {
467	sector_t s = BB_OFFSET(p[i]);
468	unsigned int length = BB_LEN(p[i]);
469	int ack = BB_ACK(p[i]);
470
471	i++;
472
473	if (unack && ack)
474	continue;
475
476	len += snprintf(page+len, PAGE_SIZE-len, "%llu %u\n",
477	(unsigned long long)s << bb->shift,
478	length << bb->shift);
479	}
480	if (unack && len == 0)
481	bb->unacked_exist = 0;
482
483	if (read_seqretry(&bb->lock, seq))
484	goto retry;
485
486	return len;
487	}
488	EXPORT_SYMBOL_GPL(badblocks_show);
489
490	/**
491	* badblocks_store() - sysfs access to bad-blocks list
492	* @bb: the badblocks structure that holds all badblock information
493	* @page: buffer received from sysfs
494	* @len: length of data received from sysfs
495	* @unack: weather to show unacknowledged badblocks
496	*
497	* Return:
498	* Length of the buffer processed or -ve error.
499	*/
500	ssize_t badblocks_store(struct badblocks bb, const char page, size_t len,
501	int unack)
502	{
503	unsigned long long sector;
504	int length;
505	char newline;
506
507	switch (sscanf(page, "%llu %d%c", &sector, &length, &newline)) {
508	case 3:
509	if (newline != '\n')
510	return -EINVAL;
511	case 2:
512	if (length <= 0)
513	return -EINVAL;
514	break;
515	default:
516	return -EINVAL;
517	}
518
519	if (badblocks_set(bb, sector, length, !unack))
520	return -ENOSPC;
521	else
522	return len;
523	}
524	EXPORT_SYMBOL_GPL(badblocks_store);
525
16263ff6 DW	526	static int __badblocks_init(struct device dev, struct badblocks bb,
16263ff6 DW	527	int enable)
9e0e252a	528	{
16263ff6	529	bb->dev = dev;
9e0e252a VV	530	bb->count = 0;
	531	if (enable)
	532	bb->shift = 0;
	533	else
	534	bb->shift = -1;
16263ff6 DW	535	if (dev)
	536	bb->page = devm_kzalloc(dev, PAGE_SIZE, GFP_KERNEL);
	537	else
	538	bb->page = kzalloc(PAGE_SIZE, GFP_KERNEL);
	539	if (!bb->page) {
9e0e252a VV	540	bb->shift = -1;
	541	return -ENOMEM;
	542	}
	543	seqlock_init(&bb->lock);
	544
	545	return 0;
	546	}
16263ff6 DW	547
	548	/**
	549	* badblocks_init() - initialize the badblocks structure
	550	* @bb: the badblocks structure that holds all badblock information
	551	* @enable: weather to enable badblocks accounting
	552	*
	553	* Return:
	554	* 0: success
	555	* -ve errno: on error
	556	*/
	557	int badblocks_init(struct badblocks *bb, int enable)
	558	{
	559	return __badblocks_init(NULL, bb, enable);
	560	}
9e0e252a VV	561	EXPORT_SYMBOL_GPL(badblocks_init);
9e0e252a VV	562
16263ff6 DW	563	int devm_init_badblocks(struct device dev, struct badblocks bb)
	564	{
	565	if (!bb)
	566	return -EINVAL;
	567	return __badblocks_init(dev, bb, 1);
	568	}
	569	EXPORT_SYMBOL_GPL(devm_init_badblocks);
	570
9e0e252a	571	/**
d3b407fb	572	* badblocks_exit() - free the badblocks structure
9e0e252a VV	573	* @bb: the badblocks structure that holds all badblock information
9e0e252a VV	574	*/
d3b407fb	575	void badblocks_exit(struct badblocks *bb)
9e0e252a	576	{
20a308f0 DW	577	if (!bb)
20a308f0 DW	578	return;
16263ff6 DW	579	if (bb->dev)
	580	devm_kfree(bb->dev, bb->page);
	581	else
	582	kfree(bb->page);
9e0e252a VV	583	bb->page = NULL;
9e0e252a VV	584	}
d3b407fb	585	EXPORT_SYMBOL_GPL(badblocks_exit);