[PATCH] maple_tree: fix alloc node fail issue

[Jiazi Li]

In the following code, the second call to the mas_node_count will
return -ENOMEM:

	mas_node_count(&maple_tree, 31);
	mas_node_count(&maple_tree, 62);

This is because get a node with node_count is MAPLE_ALLOC_SLOTS in
while loop of mas_alloc_nodes. And this will result in max_req
is zero in next loop.

Signed-off-by: Jiazi Li <jiazi.li at transsion.com>
---
 lib/maple_tree.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index aa3a5df15b8e..82c236972115 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -1272,7 +1272,9 @@ static inline void mas_alloc_nodes(struct ma_state *mas, gfp_t gfp)
 
 		node->node_count += count;
 		allocated += count;
-		node = node->slot[0];
+		do {
+			node = node->slot[0];
+		} while (unlikely(node->node_count == MAPLE_ALLOC_SLOTS));
 		requested -= count;
 	}
 	mas->alloc->total = allocated;
-- 
2.17.1