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authorJoe Thornber <ejt@redhat.com>2016-09-22 17:44:41 +0300
committerMike Snitzer <snitzer@redhat.com>2017-02-16 21:12:48 +0300
commit2151249eaabb48151cff6364adb4054b3497d62d (patch)
tree26ae3dba9537c44fbf6436f31015f1fd33b68098 /drivers/md/persistent-data/dm-bitset.c
parent48551054fc256285289f6d03abd50cb74fb71819 (diff)
downloadlinux-2151249eaabb48151cff6364adb4054b3497d62d.tar.xz
dm bitset: add dm_bitset_new()
A more efficient way of creating a populated bitset. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/persistent-data/dm-bitset.c')
-rw-r--r--drivers/md/persistent-data/dm-bitset.c42
1 files changed, 42 insertions, 0 deletions
diff --git a/drivers/md/persistent-data/dm-bitset.c b/drivers/md/persistent-data/dm-bitset.c
index 7cb28516cc19..fbf8d9bc4d15 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)