drivers/md/persistent-data/dm-bitset.c

Source file repositories/reference/linux-study-clean/drivers/md/persistent-data/dm-bitset.c

File Facts

System
Linux kernel
Corpus path
drivers/md/persistent-data/dm-bitset.c
Extension
.c
Size
7180 bytes
Lines
320
Domain
Driver Families
Bucket
drivers/md
Inferred role
Driver Families: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct packer_context {
	bit_value_fn fn;
	unsigned int nr_bits;
	void *context;
};

static int pack_bits(uint32_t index, void *value, void *context)
{
	int r;
	struct packer_context *p = context;
	unsigned int bit, nr = min(64u, p->nr_bits - (index * 64));
	uint64_t word = 0;
	bool bv;

	for (bit = 0; bit < nr; bit++) {
		r = p->fn(index * 64 + bit, &bv, p->context);
		if (r)
			return r;

		if (bv)
			set_bit(bit, (unsigned long *) &word);
		else
			clear_bit(bit, (unsigned long *) &word);
	}

	*((__le64 *) value) = cpu_to_le64(word);

	return 0;
}

int dm_bitset_new(struct dm_disk_bitset *info, dm_block_t *root,
		  uint32_t size, bit_value_fn fn, void *context)
{
	struct packer_context p;

	p.fn = fn;
	p.nr_bits = size;
	p.context = context;

	return dm_array_new(&info->array_info, root, dm_div_up(size, 64), pack_bits, &p);
}
EXPORT_SYMBOL_GPL(dm_bitset_new);

int dm_bitset_resize(struct dm_disk_bitset *info, dm_block_t root,
		     uint32_t old_nr_entries, uint32_t new_nr_entries,
		     bool default_value, dm_block_t *new_root)
{
	uint32_t old_blocks = dm_div_up(old_nr_entries, BITS_PER_ARRAY_ENTRY);
	uint32_t new_blocks = dm_div_up(new_nr_entries, BITS_PER_ARRAY_ENTRY);
	__le64 value = default_value ? cpu_to_le64(~0) : cpu_to_le64(0);

	__dm_bless_for_disk(&value);
	return dm_array_resize(&info->array_info, root, old_blocks, new_blocks,
			       &value, new_root);
}
EXPORT_SYMBOL_GPL(dm_bitset_resize);

int dm_bitset_del(struct dm_disk_bitset *info, dm_block_t root)
{
	return dm_array_del(&info->array_info, root);
}
EXPORT_SYMBOL_GPL(dm_bitset_del);

int dm_bitset_flush(struct dm_disk_bitset *info, dm_block_t root,
		    dm_block_t *new_root)
{
	int r;
	__le64 value;

	if (!info->current_index_set || !info->dirty)
		return 0;

	value = cpu_to_le64(info->current_bits);

	__dm_bless_for_disk(&value);
	r = dm_array_set_value(&info->array_info, root, info->current_index,
			       &value, new_root);
	if (r)
		return r;

	info->current_index_set = false;
	info->dirty = false;

	return 0;
}
EXPORT_SYMBOL_GPL(dm_bitset_flush);

static int read_bits(struct dm_disk_bitset *info, dm_block_t root,
		     uint32_t array_index)
{

Annotation

Implementation Notes