[PATCH v2 1/6] maple_tree: add mas_for_each_rev() helper

Suren Baghdasaryan
2024-09-02T04:41:35Z

Add mas_for_each_rev() function to iterate maple tree nodes in reverse
order.

Suggested-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
---
include/linux/maple_tree.h | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/include/linux/maple_tree.h b/include/linux/maple_tree.h
index 8e1504a81cd2..45e633806da2 100644
--- a/include/linux/maple_tree.h
+++ b/include/linux/maple_tree.h
@@ -592,6 +592,20 @@ static __always_inline void mas_reset(struct ma_state *mas)
#define mas_for_each(__mas, __entry, __max) \
while (((__entry) = mas_find((__mas), (__max))) != NULL)

+/**
+ * mas_for_each_rev() - Iterate over a range of the maple tree in reverse order.
+ * @__mas: Maple Tree operation state (maple_state)
+ * @__entry: Entry retrieved from the tree
+ * @__min: minimum index to retrieve from the tree
+ *
+ * When returned, mas->index and mas->last will hold the entire range for the
+ * entry.
+ *
+ * Note: may return the zero entry.
+ */
+#define mas_for_each_rev(__mas, __entry, __min) \
+ while (((__entry) = mas_find_rev((__mas), (__min))) != NULL)
+
#ifdef CONFIG_DEBUG_MAPLE_TREE
enum mt_dump_format {
mt_dump_dec,
--
2.46.0.469.g59c65b2a67-goog