[PATCH 2/3] maple_tree: use preallocations in mas_store_gfp()

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

Preallocate maple nodes before call to mas_wr_store_entry(). If a new
node is not needed, go directly to mas_wr_store_entry(), otherwise
allocate the needed nodes and set the MA_STATE_PREALLOC flag.

Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
---
 lib/maple_tree.c | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index e239197a57fc..25ae66e585f4 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -5478,17 +5478,33 @@ int mas_prealloc_calc(struct ma_wr_state *wr_mas)
 int mas_store_gfp(struct ma_state *mas, void *entry, gfp_t gfp)
 {
 	MA_WR_STATE(wr_mas, mas, entry);
+	int request;
 
 	mas_wr_store_setup(&wr_mas);
-	trace_ma_write(__func__, mas, 0, entry);
-retry:
+	wr_mas.content = mas_start(mas);
+
+	request = mas_prealloc_calc(&wr_mas);
+	if (!request)
+		goto store_entry;
+
+	mas_node_count_gfp(mas, request, gfp);
+	if (unlikely(mas_is_err(mas))) {
+		mas_set_alloc_req(mas, 0);
+		mas_destroy(mas);
+		mas_reset(mas);
+		return xa_err(mas->node);
+	}
+	mas->mas_flags |= MA_STATE_PREALLOC;
+
+store_entry:
 	mas_wr_store_entry(&wr_mas);
 	if (unlikely(mas_nomem(mas, gfp)))
-		goto retry;
+		goto store_entry;
 
 	if (unlikely(mas_is_err(mas)))
 		return xa_err(mas->node);
 
+	trace_ma_write(__func__, mas, 0, entry);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(mas_store_gfp);
-- 
2.41.0