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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>
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2 changed files with 91 additions and 0 deletions
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@ -168,4 +168,73 @@ int dm_bitset_test_bit(struct dm_disk_bitset *info, dm_block_t root,
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}
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EXPORT_SYMBOL_GPL(dm_bitset_test_bit);
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static int cursor_next_array_entry(struct dm_bitset_cursor *c)
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{
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int r;
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__le64 *value;
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r = dm_array_cursor_next(&c->cursor);
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if (r)
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return r;
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dm_array_cursor_get_value(&c->cursor, (void **) &value);
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c->array_index++;
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c->bit_index = 0;
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c->current_bits = le64_to_cpu(*value);
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return 0;
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}
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int dm_bitset_cursor_begin(struct dm_disk_bitset *info,
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dm_block_t root, uint32_t nr_entries,
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struct dm_bitset_cursor *c)
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{
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int r;
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__le64 *value;
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if (!nr_entries)
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return -ENODATA;
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c->info = info;
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c->entries_remaining = nr_entries;
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r = dm_array_cursor_begin(&info->array_info, root, &c->cursor);
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if (r)
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return r;
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dm_array_cursor_get_value(&c->cursor, (void **) &value);
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c->array_index = 0;
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c->bit_index = 0;
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c->current_bits = le64_to_cpu(*value);
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return r;
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}
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EXPORT_SYMBOL_GPL(dm_bitset_cursor_begin);
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void dm_bitset_cursor_end(struct dm_bitset_cursor *c)
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{
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return dm_array_cursor_end(&c->cursor);
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}
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EXPORT_SYMBOL_GPL(dm_bitset_cursor_end);
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int dm_bitset_cursor_next(struct dm_bitset_cursor *c)
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{
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int r = 0;
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if (!c->entries_remaining)
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return -ENODATA;
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c->entries_remaining--;
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if (++c->bit_index > 63)
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r = cursor_next_array_entry(c);
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return r;
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}
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EXPORT_SYMBOL_GPL(dm_bitset_cursor_next);
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bool dm_bitset_cursor_get_value(struct dm_bitset_cursor *c)
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{
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return test_bit(c->bit_index, (unsigned long *) &c->current_bits);
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}
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EXPORT_SYMBOL_GPL(dm_bitset_cursor_get_value);
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/*----------------------------------------------------------------*/
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@ -161,6 +161,28 @@ int dm_bitset_test_bit(struct dm_disk_bitset *info, dm_block_t root,
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int dm_bitset_flush(struct dm_disk_bitset *info, dm_block_t root,
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dm_block_t *new_root);
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struct dm_bitset_cursor {
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struct dm_disk_bitset *info;
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struct dm_array_cursor cursor;
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uint32_t entries_remaining;
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uint32_t array_index;
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uint32_t bit_index;
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uint64_t current_bits;
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};
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/*
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* Make sure you've flush any dm_disk_bitset and updated the root before
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* using this.
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*/
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int dm_bitset_cursor_begin(struct dm_disk_bitset *info,
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dm_block_t root, uint32_t nr_entries,
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struct dm_bitset_cursor *c);
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void dm_bitset_cursor_end(struct dm_bitset_cursor *c);
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int dm_bitset_cursor_next(struct dm_bitset_cursor *c);
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bool dm_bitset_cursor_get_value(struct dm_bitset_cursor *c);
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/*----------------------------------------------------------------*/
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#endif /* _LINUX_DM_BITSET_H */
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