[fio.git] / lib / axmap.c

/*
 * Bitmap of bitmaps, where each layer is number-of-bits-per-word smaller than
 * the previous. Hence an 'axmap', since we axe each previous layer into a
 * much smaller piece. I swear, that is why it's named like that. It has
 * nothing to do with anything remotely narcissistic.
 *
 * A set bit at layer N indicates a full word at layer N-1, and so forth. As
 * the bitmap becomes progressively more full, checking for existence
 * becomes cheaper (since fewer layers are walked, making it a lot more
 * cache friendly) and locating the next free space likewise.
 *
 * Axmaps get pretty close to optimal (1 bit per block) space usage, since
 * layers quickly diminish in size. Doing the size math is straight forward,
 * since we have log64(blocks) layers of maps. For 20000 blocks, overhead
 * is roughly 1.9%, or 1.019 bits per block. The number quickly converges
 * towards 1.0158, or 1.58% of overhead.
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

#include "../arch/arch.h"
#include "axmap.h"
#include "../minmax.h"

#if BITS_PER_LONG == 64
#define UNIT_SHIFT		6
#elif BITS_PER_LONG == 32
#define UNIT_SHIFT		5
#else
#error "Number of arch bits unknown"
#endif

#define BLOCKS_PER_UNIT		(1U << UNIT_SHIFT)
#define BLOCKS_PER_UNIT_MASK	(BLOCKS_PER_UNIT - 1)

static const unsigned long bit_masks[] = {
	0x0000000000000000, 0x0000000000000001, 0x0000000000000003, 0x0000000000000007,
	0x000000000000000f, 0x000000000000001f, 0x000000000000003f, 0x000000000000007f,
	0x00000000000000ff, 0x00000000000001ff, 0x00000000000003ff, 0x00000000000007ff,
	0x0000000000000fff, 0x0000000000001fff, 0x0000000000003fff, 0x0000000000007fff,
	0x000000000000ffff, 0x000000000001ffff, 0x000000000003ffff, 0x000000000007ffff,
	0x00000000000fffff, 0x00000000001fffff, 0x00000000003fffff, 0x00000000007fffff,
	0x0000000000ffffff, 0x0000000001ffffff, 0x0000000003ffffff, 0x0000000007ffffff,
	0x000000000fffffff, 0x000000001fffffff, 0x000000003fffffff, 0x000000007fffffff,
	0x00000000ffffffff,
#if BITS_PER_LONG == 64
	0x00000001ffffffff, 0x00000003ffffffff, 0x00000007ffffffff, 0x0000000fffffffff,
	0x0000001fffffffff, 0x0000003fffffffff, 0x0000007fffffffff, 0x000000ffffffffff,
	0x000001ffffffffff, 0x000003ffffffffff, 0x000007ffffffffff, 0x00000fffffffffff,
	0x00001fffffffffff, 0x00003fffffffffff, 0x00007fffffffffff, 0x0000ffffffffffff,
	0x0001ffffffffffff, 0x0003ffffffffffff, 0x0007ffffffffffff, 0x000fffffffffffff,
	0x001fffffffffffff, 0x003fffffffffffff, 0x007fffffffffffff, 0x00ffffffffffffff,
	0x01ffffffffffffff, 0x03ffffffffffffff, 0x07ffffffffffffff, 0x0fffffffffffffff,
	0x1fffffffffffffff, 0x3fffffffffffffff, 0x7fffffffffffffff, 0xffffffffffffffff
#endif
};

struct axmap_level {
	int level;
	unsigned long map_size;
	unsigned long *map;
};

struct axmap {
	unsigned int nr_levels;
	struct axmap_level *levels;
	uint64_t nr_bits;
};

static inline unsigned long ulog64(unsigned long val, unsigned int log)
{
	while (log-- && val)
		val >>= UNIT_SHIFT;

	return val;
}

void axmap_reset(struct axmap *axmap)
{
	int i;

	for (i = 0; i < axmap->nr_levels; i++) {
		struct axmap_level *al = &axmap->levels[i];

		memset(al->map, 0, al->map_size * sizeof(unsigned long));
	}
}

void axmap_free(struct axmap *axmap)
{
	unsigned int i;

	if (!axmap)
		return;

	for (i = 0; i < axmap->nr_levels; i++)
		free(axmap->levels[i].map);

	free(axmap->levels);
	free(axmap);
}

struct axmap *axmap_new(unsigned long nr_bits)
{
	struct axmap *axmap;
	unsigned int i, levels;

	axmap = malloc(sizeof(*axmap));
	if (!axmap)
		return NULL;

	levels = 1;
	i = (nr_bits + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT;
	while (i > 1) {
		i = (i + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT;
		levels++;
	}

	axmap->nr_levels = levels;
	axmap->levels = calloc(axmap->nr_levels, sizeof(struct axmap_level));
	axmap->nr_bits = nr_bits;

	for (i = 0; i < axmap->nr_levels; i++) {
		struct axmap_level *al = &axmap->levels[i];

		al->level = i;
		al->map_size = (nr_bits + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT;
		al->map = malloc(al->map_size * sizeof(unsigned long));
		if (!al->map)
			goto err;

		nr_bits = (nr_bits + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT;
	}

	axmap_reset(axmap);
	return axmap;
err:
	for (i = 0; i < axmap->nr_levels; i++)
		if (axmap->levels[i].map)
			free(axmap->levels[i].map);

	free(axmap->levels);
	free(axmap);
	return NULL;
}

static bool axmap_handler(struct axmap *axmap, uint64_t bit_nr,
			  bool (*func)(struct axmap_level *, unsigned long, unsigned int,
			  void *), void *data)
{
	struct axmap_level *al;
	uint64_t index = bit_nr;
	int i;

	for (i = 0; i < axmap->nr_levels; i++) {
		unsigned long offset = index >> UNIT_SHIFT;
		unsigned int bit = index & BLOCKS_PER_UNIT_MASK;

		al = &axmap->levels[i];

		if (func(al, offset, bit, data))
			return true;

		if (index)
			index >>= UNIT_SHIFT;
	}

	return false;
}

static bool axmap_handler_topdown(struct axmap *axmap, uint64_t bit_nr,
	bool (*func)(struct axmap_level *, unsigned long, unsigned int, void *))
{
	int i;

	for (i = axmap->nr_levels - 1; i >= 0; i--) {
		unsigned long index = ulog64(bit_nr, i);
		unsigned long offset = index >> UNIT_SHIFT;
		unsigned int bit = index & BLOCKS_PER_UNIT_MASK;

		if (func(&axmap->levels[i], offset, bit, NULL))
			return true;
	}

	return false;
}

struct axmap_set_data {
	unsigned int nr_bits;
	unsigned int set_bits;
};

static bool axmap_set_fn(struct axmap_level *al, unsigned long offset,
			 unsigned int bit, void *__data)
{
	struct axmap_set_data *data = __data;
	unsigned long mask, overlap;
	unsigned int nr_bits;

	nr_bits = min(data->nr_bits, BLOCKS_PER_UNIT - bit);

	mask = bit_masks[nr_bits] << bit;

	/*
	 * Mask off any potential overlap, only sets contig regions
	 */
	overlap = al->map[offset] & mask;
	if (overlap == mask) {
done:
		data->set_bits = 0;
		return true;
	}

	if (overlap) {
		const int __bit = ffz(~overlap);

		nr_bits = __bit - bit;
		if (!nr_bits)
			goto done;

		mask = bit_masks[nr_bits] << bit;
	}

	assert(mask);
	assert(!(al->map[offset] & mask));
	al->map[offset] |= mask;

	if (!al->level)
		data->set_bits = nr_bits;

	data->nr_bits = 1;
	return al->map[offset] != -1UL;
}

static void __axmap_set(struct axmap *axmap, uint64_t bit_nr,
			 struct axmap_set_data *data)
{
	unsigned int set_bits, nr_bits = data->nr_bits;

	if (bit_nr > axmap->nr_bits)
		return;
	else if (bit_nr + nr_bits > axmap->nr_bits)
		nr_bits = axmap->nr_bits - bit_nr;

	set_bits = 0;
	while (nr_bits) {
		axmap_handler(axmap, bit_nr, axmap_set_fn, data);
		set_bits += data->set_bits;

		if (!data->set_bits ||
		    data->set_bits != (BLOCKS_PER_UNIT - nr_bits))
			break;

		nr_bits -= data->set_bits;
		bit_nr += data->set_bits;

		data->nr_bits = nr_bits;
	}

	data->set_bits = set_bits;
}

void axmap_set(struct axmap *axmap, uint64_t bit_nr)
{
	struct axmap_set_data data = { .nr_bits = 1, };

	__axmap_set(axmap, bit_nr, &data);
}

unsigned int axmap_set_nr(struct axmap *axmap, uint64_t bit_nr,
			  unsigned int nr_bits)
{
	unsigned int set_bits = 0;

	do {
		struct axmap_set_data data = { .nr_bits = nr_bits, };
		unsigned int max_bits, this_set;

		max_bits = BLOCKS_PER_UNIT - (bit_nr & BLOCKS_PER_UNIT_MASK);
		if (nr_bits > max_bits)
			data.nr_bits = max_bits;

		this_set = data.nr_bits;
		__axmap_set(axmap, bit_nr, &data);
		set_bits += data.set_bits;
		if (data.set_bits != this_set)
			break;

		nr_bits -= data.set_bits;
		bit_nr += data.set_bits;
	} while (nr_bits);

	return set_bits;
}

static bool axmap_isset_fn(struct axmap_level *al, unsigned long offset,
			   unsigned int bit, void *unused)
{
	return (al->map[offset] & (1UL << bit)) != 0;
}

bool axmap_isset(struct axmap *axmap, uint64_t bit_nr)
{
	if (bit_nr <= axmap->nr_bits)
		return axmap_handler_topdown(axmap, bit_nr, axmap_isset_fn);

	return false;
}

/*
 * Find the first free bit that is at least as large as bit_nr.  Return
 * -1 if no free bit is found before the end of the map.
 */
static uint64_t axmap_find_first_free(struct axmap *axmap, uint64_t bit_nr)
{
	int i;
	unsigned long temp;
	unsigned int bit;
	uint64_t offset, base_index, index;
	struct axmap_level *al;

	index = 0;
	for (i = axmap->nr_levels - 1; i >= 0; i--) {
		al = &axmap->levels[i];

		/* Shift previously calculated index for next level */
		index <<= UNIT_SHIFT;

		/*
		 * Start from an index that's at least as large as the
		 * originally passed in bit number.
		 */
		base_index = bit_nr >> (UNIT_SHIFT * i);
		if (index < base_index)
			index = base_index;

		/* Get the offset and bit for this level */
		offset = index >> UNIT_SHIFT;
		bit = index & BLOCKS_PER_UNIT_MASK;

		/*
		 * If the previous level had unused bits in its last
		 * word, the offset could be bigger than the map at
		 * this level. That means no free bits exist before the
		 * end of the map, so return -1.
		 */
		if (offset >= al->map_size)
			return -1ULL;

		/* Check the first word starting with the specific bit */
		temp = ~bit_masks[bit] & ~al->map[offset];
		if (temp)
			goto found;

		/*
		 * No free bit in the first word, so iterate
		 * looking for a word with one or more free bits.
		 */
		for (offset++; offset < al->map_size; offset++) {
			temp = ~al->map[offset];
			if (temp)
				goto found;
		}

		/* Did not find a free bit */
		return -1ULL;

found:
		/* Compute the index of the free bit just found */
		index = (offset << UNIT_SHIFT) + ffz(~temp);
	}

	/* If found an unused bit in the last word of level 0, return -1 */
	if (index >= axmap->nr_bits)
		return -1ULL;

	return index;
}

/*
 * 'bit_nr' is already set. Find the next free bit after this one.
 * Return -1 if no free bits found.
 */
uint64_t axmap_next_free(struct axmap *axmap, uint64_t bit_nr)
{
	uint64_t ret;
	uint64_t next_bit = bit_nr + 1;
	unsigned long temp;
	uint64_t offset;
	unsigned int bit;

	if (bit_nr >= axmap->nr_bits)
		return -1ULL;

	/* If at the end of the map, wrap-around */
	if (next_bit == axmap->nr_bits)
		next_bit = 0;

	offset = next_bit >> UNIT_SHIFT;
	bit = next_bit & BLOCKS_PER_UNIT_MASK;

	/*
	 * As an optimization, do a quick check for a free bit
	 * in the current word at level 0. If not found, do
	 * a topdown search.
	 */
	temp = ~bit_masks[bit] & ~axmap->levels[0].map[offset];
	if (temp) {
		ret = (offset << UNIT_SHIFT) + ffz(~temp);

		/* Might have found an unused bit at level 0 */
		if (ret >= axmap->nr_bits)
			ret = -1ULL;
	} else
		ret = axmap_find_first_free(axmap, next_bit);

	/*
	 * If there are no free bits starting at next_bit and going
	 * to the end of the map, wrap around by searching again
	 * starting at bit 0.
	 */
	if (ret == -1ULL && next_bit != 0)
		ret = axmap_find_first_free(axmap, 0);
	return ret;
}
Commit	Line	Data
7ebd796f JA	1	/*
	2	* Bitmap of bitmaps, where each layer is number-of-bits-per-word smaller than
	3	* the previous. Hence an 'axmap', since we axe each previous layer into a
	4	* much smaller piece. I swear, that is why it's named like that. It has
	5	* nothing to do with anything remotely narcissistic.
	6	*
	7	* A set bit at layer N indicates a full word at layer N-1, and so forth. As
de8f6de9	8	* the bitmap becomes progressively more full, checking for existence
7ebd796f JA	9	* becomes cheaper (since fewer layers are walked, making it a lot more
	10	* cache friendly) and locating the next free space likewise.
	11	*
	12	* Axmaps get pretty close to optimal (1 bit per block) space usage, since
	13	* layers quickly diminish in size. Doing the size math is straight forward,
	14	* since we have log64(blocks) layers of maps. For 20000 blocks, overhead
	15	* is roughly 1.9%, or 1.019 bits per block. The number quickly converges
	16	* towards 1.0158, or 1.58% of overhead.
	17	*/
	18	#include <stdio.h>
	19	#include <stdlib.h>
	20	#include <string.h>
	21	#include <assert.h>
	22
	23	#include "../arch/arch.h"
	24	#include "axmap.h"
7ebd796f JA	25	#include "../minmax.h"
	26
	27	#if BITS_PER_LONG == 64
	28	#define UNIT_SHIFT 6
	29	#elif BITS_PER_LONG == 32
	30	#define UNIT_SHIFT 5
	31	#else
	32	#error "Number of arch bits unknown"
	33	#endif
	34
e6f735f0	35	#define BLOCKS_PER_UNIT (1U << UNIT_SHIFT)
7ebd796f JA	36	#define BLOCKS_PER_UNIT_MASK (BLOCKS_PER_UNIT - 1)
7ebd796f JA	37
76dd186e JA	38	static const unsigned long bit_masks[] = {
	39	0x0000000000000000, 0x0000000000000001, 0x0000000000000003, 0x0000000000000007,
	40	0x000000000000000f, 0x000000000000001f, 0x000000000000003f, 0x000000000000007f,
	41	0x00000000000000ff, 0x00000000000001ff, 0x00000000000003ff, 0x00000000000007ff,
	42	0x0000000000000fff, 0x0000000000001fff, 0x0000000000003fff, 0x0000000000007fff,
	43	0x000000000000ffff, 0x000000000001ffff, 0x000000000003ffff, 0x000000000007ffff,
	44	0x00000000000fffff, 0x00000000001fffff, 0x00000000003fffff, 0x00000000007fffff,
	45	0x0000000000ffffff, 0x0000000001ffffff, 0x0000000003ffffff, 0x0000000007ffffff,
	46	0x000000000fffffff, 0x000000001fffffff, 0x000000003fffffff, 0x000000007fffffff,
	47	0x00000000ffffffff,
	48	#if BITS_PER_LONG == 64
	49	0x00000001ffffffff, 0x00000003ffffffff, 0x00000007ffffffff, 0x0000000fffffffff,
	50	0x0000001fffffffff, 0x0000003fffffffff, 0x0000007fffffffff, 0x000000ffffffffff,
	51	0x000001ffffffffff, 0x000003ffffffffff, 0x000007ffffffffff, 0x00000fffffffffff,
	52	0x00001fffffffffff, 0x00003fffffffffff, 0x00007fffffffffff, 0x0000ffffffffffff,
	53	0x0001ffffffffffff, 0x0003ffffffffffff, 0x0007ffffffffffff, 0x000fffffffffffff,
	54	0x001fffffffffffff, 0x003fffffffffffff, 0x007fffffffffffff, 0x00ffffffffffffff,
	55	0x01ffffffffffffff, 0x03ffffffffffffff, 0x07ffffffffffffff, 0x0fffffffffffffff,
	56	0x1fffffffffffffff, 0x3fffffffffffffff, 0x7fffffffffffffff, 0xffffffffffffffff
	57	#endif
	58	};
	59
7ebd796f JA	60	struct axmap_level {
	61	int level;
	62	unsigned long map_size;
	63	unsigned long *map;
	64	};
	65
	66	struct axmap {
	67	unsigned int nr_levels;
	68	struct axmap_level *levels;
47d94b0b	69	uint64_t nr_bits;
7ebd796f JA	70	};
7ebd796f JA	71
76dd186e	72	static inline unsigned long ulog64(unsigned long val, unsigned int log)
7ebd796f JA	73	{
	74	while (log-- && val)
	75	val >>= UNIT_SHIFT;
	76
	77	return val;
	78	}
	79
	80	void axmap_reset(struct axmap *axmap)
	81	{
	82	int i;
	83
	84	for (i = 0; i < axmap->nr_levels; i++) {
	85	struct axmap_level *al = &axmap->levels[i];
	86
	87	memset(al->map, 0, al->map_size * sizeof(unsigned long));
	88	}
	89	}
	90
	91	void axmap_free(struct axmap *axmap)
	92	{
	93	unsigned int i;
	94
	95	if (!axmap)
	96	return;
	97
	98	for (i = 0; i < axmap->nr_levels; i++)
aded30f7	99	free(axmap->levels[i].map);
7ebd796f	100
aded30f7 JA	101	free(axmap->levels);
aded30f7 JA	102	free(axmap);
7ebd796f JA	103	}
	104
	105	struct axmap *axmap_new(unsigned long nr_bits)
	106	{
	107	struct axmap *axmap;
	108	unsigned int i, levels;
	109
aded30f7	110	axmap = malloc(sizeof(*axmap));
7ebd796f JA	111	if (!axmap)
	112	return NULL;
	113
	114	levels = 1;
	115	i = (nr_bits + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT;
	116	while (i > 1) {
	117	i = (i + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT;
	118	levels++;
	119	}
	120
	121	axmap->nr_levels = levels;
2404b2c3	122	axmap->levels = calloc(axmap->nr_levels, sizeof(struct axmap_level));
47d94b0b	123	axmap->nr_bits = nr_bits;
7ebd796f JA	124
	125	for (i = 0; i < axmap->nr_levels; i++) {
	126	struct axmap_level *al = &axmap->levels[i];
	127
	128	al->level = i;
	129	al->map_size = (nr_bits + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT;
aded30f7	130	al->map = malloc(al->map_size * sizeof(unsigned long));
7ebd796f JA	131	if (!al->map)
	132	goto err;
	133
	134	nr_bits = (nr_bits + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT;
	135	}
	136
	137	axmap_reset(axmap);
	138	return axmap;
	139	err:
	140	for (i = 0; i < axmap->nr_levels; i++)
	141	if (axmap->levels[i].map)
aded30f7	142	free(axmap->levels[i].map);
7ebd796f	143
aded30f7	144	free(axmap->levels);
bb1116fe	145	free(axmap);
7ebd796f JA	146	return NULL;
	147	}
	148
e39c0676 JA	149	static bool axmap_handler(struct axmap *axmap, uint64_t bit_nr,
e39c0676 JA	150	bool (func)(struct axmap_level , unsigned long, unsigned int,
7ebd796f JA	151	void ), void data)
	152	{
	153	struct axmap_level *al;
edfca254	154	uint64_t index = bit_nr;
7ebd796f JA	155	int i;
	156
	157	for (i = 0; i < axmap->nr_levels; i++) {
7ebd796f JA	158	unsigned long offset = index >> UNIT_SHIFT;
	159	unsigned int bit = index & BLOCKS_PER_UNIT_MASK;
	160
	161	al = &axmap->levels[i];
	162
	163	if (func(al, offset, bit, data))
e39c0676	164	return true;
edfca254 JA	165
	166	if (index)
	167	index >>= UNIT_SHIFT;
7ebd796f JA	168	}
7ebd796f JA	169
e39c0676	170	return false;
7ebd796f JA	171	}
7ebd796f JA	172
e39c0676	173	static bool axmap_handler_topdown(struct axmap *axmap, uint64_t bit_nr,
c406445a	174	bool (func)(struct axmap_level , unsigned long, unsigned int, void *))
7ebd796f	175	{
76dd186e	176	int i;
7ebd796f JA	177
7ebd796f JA	178	for (i = axmap->nr_levels - 1; i >= 0; i--) {
76dd186e	179	unsigned long index = ulog64(bit_nr, i);
7ebd796f JA	180	unsigned long offset = index >> UNIT_SHIFT;
	181	unsigned int bit = index & BLOCKS_PER_UNIT_MASK;
	182
41264298	183	if (func(&axmap->levels[i], offset, bit, NULL))
e39c0676	184	return true;
7ebd796f JA	185	}
7ebd796f JA	186
e39c0676	187	return false;
7ebd796f JA	188	}
7ebd796f JA	189
7ebd796f JA	190	struct axmap_set_data {
	191	unsigned int nr_bits;
	192	unsigned int set_bits;
7ebd796f JA	193	};
7ebd796f JA	194
e39c0676	195	static bool axmap_set_fn(struct axmap_level *al, unsigned long offset,
7ebd796f JA	196	unsigned int bit, void *__data)
	197	{
	198	struct axmap_set_data *data = __data;
	199	unsigned long mask, overlap;
	200	unsigned int nr_bits;
	201
	202	nr_bits = min(data->nr_bits, BLOCKS_PER_UNIT - bit);
	203
	204	mask = bit_masks[nr_bits] << bit;
	205
	206	/*
	207	* Mask off any potential overlap, only sets contig regions
	208	*/
	209	overlap = al->map[offset] & mask;
bd71edce JA	210	if (overlap == mask) {
	211	done:
	212	data->set_bits = 0;
e39c0676	213	return true;
bd71edce	214	}
7ebd796f	215
8cd5a2fd JA	216	if (overlap) {
8cd5a2fd JA	217	const int __bit = ffz(~overlap);
7ebd796f	218
c2e48e0e JA	219	nr_bits = __bit - bit;
c2e48e0e JA	220	if (!nr_bits)
bd71edce	221	goto done;
8cd5a2fd	222
8cd5a2fd	223	mask = bit_masks[nr_bits] << bit;
7ebd796f JA	224	}
	225
	226	assert(mask);
	227	assert(!(al->map[offset] & mask));
7ebd796f JA	228	al->map[offset] \|= mask;
	229
	230	if (!al->level)
	231	data->set_bits = nr_bits;
	232
	233	data->nr_bits = 1;
	234	return al->map[offset] != -1UL;
	235	}
	236
	237	static void __axmap_set(struct axmap *axmap, uint64_t bit_nr,
	238	struct axmap_set_data *data)
	239	{
	240	unsigned int set_bits, nr_bits = data->nr_bits;
	241
47d94b0b JA	242	if (bit_nr > axmap->nr_bits)
	243	return;
	244	else if (bit_nr + nr_bits > axmap->nr_bits)
	245	nr_bits = axmap->nr_bits - bit_nr;
	246
7ebd796f JA	247	set_bits = 0;
	248	while (nr_bits) {
	249	axmap_handler(axmap, bit_nr, axmap_set_fn, data);
	250	set_bits += data->set_bits;
	251
0bfdf9f1 JA	252	if (!data->set_bits \|\|
0bfdf9f1 JA	253	data->set_bits != (BLOCKS_PER_UNIT - nr_bits))
7ebd796f JA	254	break;
	255
	256	nr_bits -= data->set_bits;
	257	bit_nr += data->set_bits;
	258
	259	data->nr_bits = nr_bits;
7ebd796f JA	260	}
	261
	262	data->set_bits = set_bits;
	263	}
	264
	265	void axmap_set(struct axmap *axmap, uint64_t bit_nr)
	266	{
	267	struct axmap_set_data data = { .nr_bits = 1, };
	268
	269	__axmap_set(axmap, bit_nr, &data);
	270	}
	271
e39c0676 JA	272	unsigned int axmap_set_nr(struct axmap *axmap, uint64_t bit_nr,
e39c0676 JA	273	unsigned int nr_bits)
7ebd796f	274	{
0bfdf9f1 JA	275	unsigned int set_bits = 0;
	276
	277	do {
09d6bf09	278	struct axmap_set_data data = { .nr_bits = nr_bits, };
0bfdf9f1 JA	279	unsigned int max_bits, this_set;
	280
	281	max_bits = BLOCKS_PER_UNIT - (bit_nr & BLOCKS_PER_UNIT_MASK);
bd71edce	282	if (nr_bits > max_bits)
0bfdf9f1 JA	283	data.nr_bits = max_bits;
	284
	285	this_set = data.nr_bits;
	286	__axmap_set(axmap, bit_nr, &data);
	287	set_bits += data.set_bits;
	288	if (data.set_bits != this_set)
	289	break;
7ebd796f	290
0bfdf9f1 JA	291	nr_bits -= data.set_bits;
	292	bit_nr += data.set_bits;
	293	} while (nr_bits);
	294
	295	return set_bits;
7ebd796f JA	296	}
7ebd796f JA	297
e39c0676 JA	298	static bool axmap_isset_fn(struct axmap_level *al, unsigned long offset,
e39c0676 JA	299	unsigned int bit, void *unused)
7ebd796f JA	300	{
	301	return (al->map[offset] & (1UL << bit)) != 0;
	302	}
	303
e39c0676	304	bool axmap_isset(struct axmap *axmap, uint64_t bit_nr)
7ebd796f	305	{
ac569176	306	if (bit_nr <= axmap->nr_bits)
c406445a	307	return axmap_handler_topdown(axmap, bit_nr, axmap_isset_fn);
47d94b0b	308
e39c0676	309	return false;
7ebd796f JA	310	}
7ebd796f JA	311
b9304c5b MK	312	/*
	313	* Find the first free bit that is at least as large as bit_nr. Return
	314	* -1 if no free bit is found before the end of the map.
	315	*/
	316	static uint64_t axmap_find_first_free(struct axmap *axmap, uint64_t bit_nr)
7ebd796f	317	{
731ef4c7	318	int i;
b9304c5b MK	319	unsigned long temp;
	320	unsigned int bit;
	321	uint64_t offset, base_index, index;
	322	struct axmap_level *al;
7ebd796f	323
b9304c5b MK	324	index = 0;
	325	for (i = axmap->nr_levels - 1; i >= 0; i--) {
	326	al = &axmap->levels[i];
7ebd796f	327
b9304c5b MK	328	/* Shift previously calculated index for next level */
	329	index <<= UNIT_SHIFT;
	330
	331	/*
	332	* Start from an index that's at least as large as the
	333	* originally passed in bit number.
	334	*/
	335	base_index = bit_nr >> (UNIT_SHIFT * i);
	336	if (index < base_index)
	337	index = base_index;
	338
	339	/* Get the offset and bit for this level */
	340	offset = index >> UNIT_SHIFT;
	341	bit = index & BLOCKS_PER_UNIT_MASK;
	342
	343	/*
	344	* If the previous level had unused bits in its last
	345	* word, the offset could be bigger than the map at
	346	* this level. That means no free bits exist before the
	347	* end of the map, so return -1.
	348	*/
	349	if (offset >= al->map_size)
	350	return -1ULL;
	351
	352	/* Check the first word starting with the specific bit */
	353	temp = ~bit_masks[bit] & ~al->map[offset];
	354	if (temp)
	355	goto found;
	356
	357	/*
	358	* No free bit in the first word, so iterate
	359	* looking for a word with one or more free bits.
	360	*/
	361	for (offset++; offset < al->map_size; offset++) {
	362	temp = ~al->map[offset];
	363	if (temp)
	364	goto found;
7ebd796f	365	}
47d94b0b	366
b9304c5b MK	367	/* Did not find a free bit */
b9304c5b MK	368	return -1ULL;
7ebd796f	369
b9304c5b MK	370	found:
	371	/* Compute the index of the free bit just found */
	372	index = (offset << UNIT_SHIFT) + ffz(~temp);
7ebd796f JA	373	}
7ebd796f JA	374
b9304c5b MK	375	/* If found an unused bit in the last word of level 0, return -1 */
	376	if (index >= axmap->nr_bits)
	377	return -1ULL;
	378
	379	return index;
7ebd796f JA	380	}
	381
	382	/*
	383	* 'bit_nr' is already set. Find the next free bit after this one.
b9304c5b	384	* Return -1 if no free bits found.
7ebd796f JA	385	*/
	386	uint64_t axmap_next_free(struct axmap *axmap, uint64_t bit_nr)
	387	{
53737ae0	388	uint64_t ret;
b9304c5b MK	389	uint64_t next_bit = bit_nr + 1;
	390	unsigned long temp;
	391	uint64_t offset;
	392	unsigned int bit;
7ebd796f	393
b9304c5b MK	394	if (bit_nr >= axmap->nr_bits)
b9304c5b MK	395	return -1ULL;
12bde369	396
b9304c5b MK	397	/* If at the end of the map, wrap-around */
	398	if (next_bit == axmap->nr_bits)
	399	next_bit = 0;
7ebd796f	400
b9304c5b MK	401	offset = next_bit >> UNIT_SHIFT;
b9304c5b MK	402	bit = next_bit & BLOCKS_PER_UNIT_MASK;
7ebd796f	403
53737ae0	404	/*
b9304c5b MK	405	* As an optimization, do a quick check for a free bit
	406	* in the current word at level 0. If not found, do
	407	* a topdown search.
53737ae0	408	*/
b9304c5b MK	409	temp = ~bit_masks[bit] & ~axmap->levels[0].map[offset];
	410	if (temp) {
	411	ret = (offset << UNIT_SHIFT) + ffz(~temp);
53737ae0	412
b9304c5b MK	413	/* Might have found an unused bit at level 0 */
	414	if (ret >= axmap->nr_bits)
	415	ret = -1ULL;
	416	} else
	417	ret = axmap_find_first_free(axmap, next_bit);
	418
	419	/*
	420	* If there are no free bits starting at next_bit and going
	421	* to the end of the map, wrap around by searching again
	422	* starting at bit 0.
	423	*/
	424	if (ret == -1ULL && next_bit != 0)
	425	ret = axmap_find_first_free(axmap, 0);
	426	return ret;
7ebd796f	427	}