From: Joe Thornber <ejt@xxxxxxxxxx>
dm_btree_find_lowest_key is the reciprocal of dm_btree_find_highest_key.
Factor out common code for dm_btree_find_{highest,lowest}_key.
dm_btree_find_lowest_key is needed for an upcoming DM target, as such it
is best to get this interface in place.
Signed-off-by: Joe Thornber <ejt@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
---
drivers/md/persistent-data/dm-btree.c | 33 ++++++++++++++++++++++++++-------
drivers/md/persistent-data/dm-btree.h | 8 ++++++++
2 files changed, 34 insertions(+), 7 deletions(-)
diff --git a/drivers/md/persistent-data/dm-btree.c b/drivers/md/persistent-data/dm-btree.c
index 468e371..416060c 100644
--- a/drivers/md/persistent-data/dm-btree.c
+++ b/drivers/md/persistent-data/dm-btree.c
@@ -770,8 +770,8 @@ EXPORT_SYMBOL_GPL(dm_btree_insert_notify);
/*----------------------------------------------------------------*/
-static int find_highest_key(struct ro_spine *s, dm_block_t block,
- uint64_t *result_key, dm_block_t *next_block)
+static int find_key(struct ro_spine *s, dm_block_t block, bool find_highest,
+ uint64_t *result_key, dm_block_t *next_block)
{
int i, r;
uint32_t flags;
@@ -788,7 +788,11 @@ static int find_highest_key(struct ro_spine *s, dm_block_t block,
else
i--;
- *result_key = le64_to_cpu(ro_node(s)->keys[i]);
+ if (find_highest)
+ *result_key = le64_to_cpu(ro_node(s)->keys[i]);
+ else
+ *result_key = le64_to_cpu(ro_node(s)->keys[0]);
+
if (next_block || flags & INTERNAL_NODE)
block = value64(ro_node(s), i);
@@ -799,16 +803,16 @@ static int find_highest_key(struct ro_spine *s, dm_block_t block,
return 0;
}
-int dm_btree_find_highest_key(struct dm_btree_info *info, dm_block_t root,
- uint64_t *result_keys)
+static int dm_btree_find_key(struct dm_btree_info *info, dm_block_t root,
+ bool find_highest, uint64_t *result_keys)
{
int r = 0, count = 0, level;
struct ro_spine spine;
init_ro_spine(&spine, info);
for (level = 0; level < info->levels; level++) {
- r = find_highest_key(&spine, root, result_keys + level,
- level == info->levels - 1 ? NULL : &root);
+ r = find_key(&spine, root, find_highest, result_keys + level,
+ level == info->levels - 1 ? NULL : &root);
if (r == -ENODATA) {
r = 0;
break;
@@ -822,8 +826,23 @@ int dm_btree_find_highest_key(struct dm_btree_info *info, dm_block_t root,
return r ? r : count;
}
+
+int dm_btree_find_highest_key(struct dm_btree_info *info, dm_block_t root,
+ uint64_t *result_keys)
+{
+ return dm_btree_find_key(info, root, true, result_keys);
+}
EXPORT_SYMBOL_GPL(dm_btree_find_highest_key);
+int dm_btree_find_lowest_key(struct dm_btree_info *info, dm_block_t root,
+ uint64_t *result_keys)
+{
+ return dm_btree_find_key(info, root, false, result_keys);
+}
+EXPORT_SYMBOL_GPL(dm_btree_find_lowest_key);
+
+/*----------------------------------------------------------------*/
+
/*
* FIXME: We shouldn't use a recursive algorithm when we have limited stack
* space. Also this only works for single level trees.
diff --git a/drivers/md/persistent-data/dm-btree.h b/drivers/md/persistent-data/dm-btree.h
index 8672d15..dacfc34 100644
--- a/drivers/md/persistent-data/dm-btree.h
+++ b/drivers/md/persistent-data/dm-btree.h
@@ -137,6 +137,14 @@ int dm_btree_remove(struct dm_btree_info *info, dm_block_t root,
/*
* Returns < 0 on failure. Otherwise the number of key entries that have
* been filled out. Remember trees can have zero entries, and as such have
+ * no lowest key.
+ */
+int dm_btree_find_lowest_key(struct dm_btree_info *info, dm_block_t root,
+ uint64_t *result_keys);
+
+/*
+ * Returns < 0 on failure. Otherwise the number of key entries that have
+ * been filled out. Remember trees can have zero entries, and as such have
* no highest key.
*/
int dm_btree_find_highest_key(struct dm_btree_info *info, dm_block_t root,
--
1.8.1.4
--
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