[PATCH v4 06/17] maple_tree: preallocate nodes in mas_erase()

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

Use mas_wr_preallocate() in mas_erase() to preallocate enough nodes to
complete the erase. Add error handling by skipping the store if the
preallocation lead to some error besides no memory.

Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
---
 lib/maple_tree.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 58985107cf00..8ba52ffa778e 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -6371,14 +6371,18 @@ void *mas_erase(struct ma_state *mas)
 
 	/* Must reset to ensure spanning writes of last slot are detected */
 	mas_reset(mas);
-	mas_wr_store_setup(&wr_mas);
-	mas_wr_store_entry(&wr_mas);
+	mas_wr_preallocate(&wr_mas, NULL);
 	if (mas_nomem(mas, GFP_KERNEL)) {
 		/* in case the range of entry changed when unlocked */
 		mas->index = mas->last = index;
 		goto write_retry;
 	}
 
+	if (mas_is_err(mas))
+		goto out;
+
+	mas_wr_store_entry(&wr_mas);
+out:
 	mas_destroy(mas);
 	return entry;
 }
-- 
2.46.0