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Commit 6fe28dbf authored by Joe Thornber's avatar Joe Thornber Committed by Mike Snitzer
Browse files

dm bitset: introduce cursor api 



Signed-off-by: default avatarJoe Thornber <ejt@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 9f9ef065

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

+69 −0
Original line number Diff line number Diff line
@@ -168,4 +168,73 @@ int dm_bitset_test_bit(struct dm_disk_bitset *info, dm_block_t root, 
}

EXPORT_SYMBOL_GPL(dm_bitset_test_bit);



static int cursor_next_array_entry(struct dm_bitset_cursor *c)

{

	int r;

	__le64 *value;



	r = dm_array_cursor_next(&c->cursor);

	if (r)

		return r;



	dm_array_cursor_get_value(&c->cursor, (void **) &value);

	c->array_index++;

	c->bit_index = 0;

	c->current_bits = le64_to_cpu(*value);

	return 0;

}



int dm_bitset_cursor_begin(struct dm_disk_bitset *info,

			   dm_block_t root, uint32_t nr_entries,

			   struct dm_bitset_cursor *c)

{

	int r;

	__le64 *value;



	if (!nr_entries)

		return -ENODATA;



	c->info = info;

	c->entries_remaining = nr_entries;



	r = dm_array_cursor_begin(&info->array_info, root, &c->cursor);

	if (r)

		return r;



	dm_array_cursor_get_value(&c->cursor, (void **) &value);

	c->array_index = 0;

	c->bit_index = 0;

	c->current_bits = le64_to_cpu(*value);



	return r;

}

EXPORT_SYMBOL_GPL(dm_bitset_cursor_begin);



void dm_bitset_cursor_end(struct dm_bitset_cursor *c)

{

	return dm_array_cursor_end(&c->cursor);

}

EXPORT_SYMBOL_GPL(dm_bitset_cursor_end);



int dm_bitset_cursor_next(struct dm_bitset_cursor *c)

{

	int r = 0;



	if (!c->entries_remaining)

		return -ENODATA;



	c->entries_remaining--;

	if (++c->bit_index > 63)

		r = cursor_next_array_entry(c);



	return r;

}

EXPORT_SYMBOL_GPL(dm_bitset_cursor_next);



bool dm_bitset_cursor_get_value(struct dm_bitset_cursor *c)

{

	return test_bit(c->bit_index, (unsigned long *) &c->current_bits);

}

EXPORT_SYMBOL_GPL(dm_bitset_cursor_get_value);



/*----------------------------------------------------------------*/

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

+22 −0
Original line number Diff line number Diff line
@@ -161,6 +161,28 @@ int dm_bitset_test_bit(struct dm_disk_bitset *info, dm_block_t root, 
int dm_bitset_flush(struct dm_disk_bitset *info, dm_block_t root,

		    dm_block_t *new_root);



struct dm_bitset_cursor {

	struct dm_disk_bitset *info;

	struct dm_array_cursor cursor;



	uint32_t entries_remaining;

	uint32_t array_index;

	uint32_t bit_index;

	uint64_t current_bits;

};



/*

 * Make sure you've flush any dm_disk_bitset and updated the root before

 * using this.

 */

int dm_bitset_cursor_begin(struct dm_disk_bitset *info,

			   dm_block_t root, uint32_t nr_entries,

			   struct dm_bitset_cursor *c);

void dm_bitset_cursor_end(struct dm_bitset_cursor *c);



int dm_bitset_cursor_next(struct dm_bitset_cursor *c);

bool dm_bitset_cursor_get_value(struct dm_bitset_cursor *c);



/*----------------------------------------------------------------*/



#endif /* _LINUX_DM_BITSET_H */