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dm bitset: introduce cursor api 

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Joe Thornber 2016-10-03 14:15:02 -04:00 committed by Mike Snitzer
parent 9f9ef0657d
commit 6fe28dbf05
2 changed files with 91 additions and 0 deletions
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69
drivers/md/persistent-data/dm-bitset.c
View File

@ -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);
/*----------------------------------------------------------------*/

22
drivers/md/persistent-data/dm-bitset.h
View File

@ -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 */