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path: root/drivers/md/persistent-data/dm-bitset.c
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Diffstat (limited to 'drivers/md/persistent-data/dm-bitset.c')
-rw-r--r--drivers/md/persistent-data/dm-bitset.c146
1 files changed, 146 insertions, 0 deletions
diff --git a/drivers/md/persistent-data/dm-bitset.c b/drivers/md/persistent-data/dm-bitset.c
index 36f7cc2c7109..b7208d82e748 100644
--- a/drivers/md/persistent-data/dm-bitset.c
+++ b/drivers/md/persistent-data/dm-bitset.c
@@ -39,6 +39,48 @@ int dm_bitset_empty(struct dm_disk_bitset *info, dm_block_t *root)
}
EXPORT_SYMBOL_GPL(dm_bitset_empty);
+struct packer_context {
+ bit_value_fn fn;
+ unsigned nr_bits;
+ void *context;
+};
+
+static int pack_bits(uint32_t index, void *value, void *context)
+{
+ int r;
+ struct packer_context *p = context;
+ unsigned 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)
@@ -168,4 +210,108 @@ 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);
+
+int dm_bitset_cursor_skip(struct dm_bitset_cursor *c, uint32_t count)
+{
+ int r;
+ __le64 *value;
+ uint32_t nr_array_skip;
+ uint32_t remaining_in_word = 64 - c->bit_index;
+
+ if (c->entries_remaining < count)
+ return -ENODATA;
+
+ if (count < remaining_in_word) {
+ c->bit_index += count;
+ c->entries_remaining -= count;
+ return 0;
+
+ } else {
+ c->entries_remaining -= remaining_in_word;
+ count -= remaining_in_word;
+ }
+
+ nr_array_skip = (count / 64) + 1;
+ r = dm_array_cursor_skip(&c->cursor, nr_array_skip);
+ if (r)
+ return r;
+
+ dm_array_cursor_get_value(&c->cursor, (void **) &value);
+ c->entries_remaining -= count;
+ c->array_index += nr_array_skip;
+ c->bit_index = count & 63;
+ c->current_bits = le64_to_cpu(*value);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dm_bitset_cursor_skip);
+
+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);
+
/*----------------------------------------------------------------*/