maple_tree: Fix mas_expected_entries() off by one

When inserting nodes, a final call to split the nodes will require a new
parent.  Add this as the working area for mas_expected_entries().

Add a maple state flag which will WARN_ON() if there is insufficient
nodes allocated.

Export mas_is_err() to be used in checking mas_store() returns
externally.

Fixes: 06b152b7980a (Maple Tree: add new data structure)
Reported-by: Yu Zhao <yuzhao@google.com>
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>

diff --git a/include/linux/maple_tree.h b/include/linux/maple_tree.h
index bdb891b0d2b53f95ba151e964a7409f07591aa1d..a30e03b06bedebc4274229a2e2ebe6e2ae39a2d6 100644 (file)
--- a/include/linux/maple_tree.h
+++ b/include/linux/maple_tree.h
@@ -457,6 +457,7 @@ void mas_store_prealloc(struct ma_state *mas, void *entry);
 void *mas_find(struct ma_state *mas, unsigned long max);
 void *mas_find_rev(struct ma_state *mas, unsigned long min);
 int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp);
+bool mas_is_err(struct ma_state *mas);
 
 bool mas_nomem(struct ma_state *mas, gfp_t gfp);
 void mas_pause(struct ma_state *mas);

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index d00ad50b258e4c0dc25842a74878f3598921be74..a3ead5fb5307c8bb3c986a7437105358949ac991 100644 (file)
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -64,9 +64,15 @@
 
 #define MA_ROOT_PARENT 1
 
-/* Maple state flags */
+/*
+ * Maple state flags
+ * * MA_STATE_BULK             - Bulk insert mode
+ * * MA_STATE_REBALANCE                - Indicate a rebalance during bulk insert
+ * * MA_STATE_PREALLOC         - Preallocated nodes, WARN_ON allocation
+ */
 #define MA_STATE_BULK          1
 #define MA_STATE_REBALANCE     2
+#define MA_STATE_PREALLOC      4
 
 #define ma_parent_ptr(x) ((struct maple_pnode *)(x))
 #define ma_mnode_ptr(x) ((struct maple_node *)(x))
@@ -243,7 +249,7 @@ static inline bool mas_is_start(struct ma_state *mas)
        return mas->node == MAS_START;
 }
 
-static inline bool mas_is_err(struct ma_state *mas)
+bool mas_is_err(struct ma_state *mas)
 {
        return xa_is_err(mas->node);
 }
@@ -1215,6 +1221,12 @@ static inline void mas_alloc_nodes(struct ma_state *mas, gfp_t gfp)
                return;
 
        mas_set_alloc_req(mas, 0);
+       if (mas->mas_flags & MA_STATE_PREALLOC) {
+               if (allocated)
+                       return;
+               WARN_ON(!allocated);
+       }
+
        if (!allocated || mas->alloc->node_count == MAPLE_ALLOC_SLOTS - 1) {
                node = (struct maple_alloc *)mt_alloc_one(gfp);
                if (!node)
@@ -5706,6 +5718,7 @@ int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp)
        int ret;
 
        mas_node_count_gfp(mas, 1 + mas_mt_height(mas) * 3, gfp);
+       mas->mas_flags |= MA_STATE_PREALLOC;
        if (likely(!mas_is_err(mas)))
                return 0;
 
@@ -5748,7 +5761,7 @@ void mas_destroy(struct ma_state *mas)
 
                mas->mas_flags &= ~MA_STATE_REBALANCE;
        }
-       mas->mas_flags &= ~MA_STATE_BULK;
+       mas->mas_flags &= ~(MA_STATE_BULK|MA_STATE_PREALLOC);
 
        while (mas->alloc && !((unsigned long)mas->alloc & 0x1)) {
                node = mas->alloc;
@@ -5799,7 +5812,6 @@ int mas_expected_entries(struct ma_state *mas, unsigned long nr_entries)
         * insertion of entries.
         */
        nr_nodes = max(nr_entries, nr_entries * 2 + 1);
-
        if (!mt_is_alloc(mas->tree))
                nonleaf_cap = MAPLE_RANGE64_SLOTS - 2;
 
@@ -5807,7 +5819,11 @@ int mas_expected_entries(struct ma_state *mas, unsigned long nr_entries)
        nr_nodes = DIV_ROUND_UP(nr_nodes, MAPLE_RANGE64_SLOTS - 1);
        /* Internal nodes */
        nr_nodes += DIV_ROUND_UP(nr_nodes, nonleaf_cap);
-       mas_node_count(mas, nr_nodes);
+       /* Add one for working room */
+       mas_node_count(mas, nr_nodes + 1);
+
+       /* Detect if allocations run out */
+       mas->mas_flags |= MA_STATE_PREALLOC;
 
        if (!mas_is_err(mas))
                return 0;