[PATCH v4 16/17] maple_tree: remove unneeded mas_wr_walk() in mas_store_prealloc()

[Sidhartha Kumar <sidhartha.kumar@oracle.com>]

Users of mas_store_prealloc() enter this function with nodes already
preallocated. This means the store type must be already set. We can then
remove the call to mas_wr_store_type() and initialize the write state to
continue the partial walk that was done when determining the store type.

Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
---
 lib/maple_tree.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 8c1a1a483395..73ce63d9c3a0 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -3979,9 +3979,6 @@ static inline void mas_wr_end_piv(struct ma_wr_state *wr_mas)
 		wr_mas->end_piv = wr_mas->pivots[wr_mas->offset_end];
 	else
 		wr_mas->end_piv = wr_mas->mas->max;
-
-	if (!wr_mas->entry)
-		mas_wr_extend_null(wr_mas);
 }
 
 static inline unsigned char mas_wr_new_end(struct ma_wr_state *wr_mas)
@@ -5532,8 +5529,19 @@ void mas_store_prealloc(struct ma_state *mas, void *entry)
 {
 	MA_WR_STATE(wr_mas, mas, entry);
 
-	mas_wr_prealloc_setup(&wr_mas);
-	mas_wr_store_type(&wr_mas);
+	if (mas->store_type == wr_store_root) {
+		mas_wr_prealloc_setup(&wr_mas);
+		goto store;
+	}
+
+	mas_wr_walk_descend(&wr_mas);
+	if (mas->store_type != wr_spanning_store) {
+		/* set wr_mas->content to current slot */
+		wr_mas.content = mas_slot_locked(mas, wr_mas.slots, mas->offset);
+		mas_wr_end_piv(&wr_mas);
+	}
+
+store:
 	trace_ma_write(__func__, mas, 0, entry);
 	mas_wr_store_entry(&wr_mas);
 	MAS_WR_BUG_ON(&wr_mas, mas_is_err(mas));
-- 
2.46.0