maple_tree: detect dead nodes in mas_start()

[platform/kernel/linux-starfive.git] / lib / maple_tree.c

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 646297c..3d53339 100644 (file)
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -544,6 +544,7 @@ static inline bool ma_dead_node(const struct maple_node *node)
 
        return (parent == node);
 }
+
 /*
  * mte_dead_node() - check if the @enode is dead.
  * @enode: The encoded maple node
@@ -625,6 +626,8 @@ static inline unsigned int mas_alloc_req(const struct ma_state *mas)
  * @node - the maple node
  * @type - the node type
  *
+ * In the event of a dead node, this array may be %NULL
+ *
  * Return: A pointer to the maple node pivots
  */
 static inline unsigned long *ma_pivots(struct maple_node *node,
@@ -1096,8 +1099,11 @@ static int mas_ascend(struct ma_state *mas)
                a_type = mas_parent_enum(mas, p_enode);
                a_node = mte_parent(p_enode);
                a_slot = mte_parent_slot(p_enode);
-               pivots = ma_pivots(a_node, a_type);
                a_enode = mt_mk_node(a_node, a_type);
+               pivots = ma_pivots(a_node, a_type);
+
+               if (unlikely(ma_dead_node(a_node)))
+                       return 1;
 
                if (!set_min && a_slot) {
                        set_min = true;
@@ -1354,12 +1360,16 @@ static inline struct maple_enode *mas_start(struct ma_state *mas)
                mas->max = ULONG_MAX;
                mas->depth = 0;
 
+retry:
                root = mas_root(mas);
                /* Tree with nodes */
                if (likely(xa_is_node(root))) {
                        mas->depth = 1;
                        mas->node = mte_safe_root(root);
                        mas->offset = 0;
+                       if (mte_dead_node(mas->node))
+                               goto retry;
+
                        return NULL;
                }
 
@@ -1401,6 +1411,9 @@ static inline unsigned char ma_data_end(struct maple_node *node,
 {
        unsigned char offset;
 
+       if (!pivots)
+               return 0;
+
        if (type == maple_arange_64)
                return ma_meta_end(node, type);
 
@@ -1436,6 +1449,9 @@ static inline unsigned char mas_data_end(struct ma_state *mas)
                return ma_meta_end(node, type);
 
        pivots = ma_pivots(node, type);
+       if (unlikely(ma_dead_node(node)))
+               return 0;
+
        offset = mt_pivots[type] - 1;
        if (likely(!pivots[offset]))
                return ma_meta_end(node, type);
@@ -4505,6 +4521,9 @@ static inline int mas_prev_node(struct ma_state *mas, unsigned long min)
        node = mas_mn(mas);
        slots = ma_slots(node, mt);
        pivots = ma_pivots(node, mt);
+       if (unlikely(ma_dead_node(node)))
+               return 1;
+
        mas->max = pivots[offset];
        if (offset)
                mas->min = pivots[offset - 1] + 1;
@@ -4526,6 +4545,9 @@ static inline int mas_prev_node(struct ma_state *mas, unsigned long min)
                slots = ma_slots(node, mt);
                pivots = ma_pivots(node, mt);
                offset = ma_data_end(node, mt, pivots, mas->max);
+               if (unlikely(ma_dead_node(node)))
+                       return 1;
+
                if (offset)
                        mas->min = pivots[offset - 1] + 1;
 
@@ -4574,6 +4596,7 @@ static inline int mas_next_node(struct ma_state *mas, struct maple_node *node,
        struct maple_enode *enode;
        int level = 0;
        unsigned char offset;
+       unsigned char node_end;
        enum maple_type mt;
        void __rcu **slots;
 
@@ -4597,7 +4620,11 @@ static inline int mas_next_node(struct ma_state *mas, struct maple_node *node,
                node = mas_mn(mas);
                mt = mte_node_type(mas->node);
                pivots = ma_pivots(node, mt);
-       } while (unlikely(offset == ma_data_end(node, mt, pivots, mas->max)));
+               node_end = ma_data_end(node, mt, pivots, mas->max);
+               if (unlikely(ma_dead_node(node)))
+                       return 1;
+
+       } while (unlikely(offset == node_end));
 
        slots = ma_slots(node, mt);
        pivot = mas_safe_pivot(mas, pivots, ++offset, mt);
@@ -4613,6 +4640,9 @@ static inline int mas_next_node(struct ma_state *mas, struct maple_node *node,
                mt = mte_node_type(mas->node);
                slots = ma_slots(node, mt);
                pivots = ma_pivots(node, mt);
+               if (unlikely(ma_dead_node(node)))
+                       return 1;
+
                offset = 0;
                pivot = pivots[0];
        }
@@ -4659,11 +4689,14 @@ static inline void *mas_next_nentry(struct ma_state *mas,
                return NULL;
        }
 
-       pivots = ma_pivots(node, type);
        slots = ma_slots(node, type);
-       mas->index = mas_safe_min(mas, pivots, mas->offset);
+       pivots = ma_pivots(node, type);
        count = ma_data_end(node, type, pivots, mas->max);
-       if (ma_dead_node(node))
+       if (unlikely(ma_dead_node(node)))
+               return NULL;
+
+       mas->index = mas_safe_min(mas, pivots, mas->offset);
+       if (unlikely(ma_dead_node(node)))
                return NULL;
 
        if (mas->index > max)
@@ -4817,6 +4850,11 @@ retry:
 
        slots = ma_slots(mn, mt);
        pivots = ma_pivots(mn, mt);
+       if (unlikely(ma_dead_node(mn))) {
+               mas_rewalk(mas, index);
+               goto retry;
+       }
+
        if (offset == mt_pivots[mt])
                pivot = mas->max;
        else
@@ -5099,35 +5137,21 @@ static inline bool mas_rewind_node(struct ma_state *mas)
  */
 static inline bool mas_skip_node(struct ma_state *mas)
 {
-       unsigned char slot, slot_count;
-       unsigned long *pivots;
-       enum maple_type mt;
+       if (mas_is_err(mas))
+               return false;
 
-       mt = mte_node_type(mas->node);
-       slot_count = mt_slots[mt] - 1;
        do {
                if (mte_is_root(mas->node)) {
-                       slot = mas->offset;
-                       if (slot > slot_count) {
+                       if (mas->offset >= mas_data_end(mas)) {
                                mas_set_err(mas, -EBUSY);
                                return false;
                        }
                } else {
                        mas_ascend(mas);
-                       slot = mas->offset;
-                       mt = mte_node_type(mas->node);
-                       slot_count = mt_slots[mt] - 1;
                }
-       } while (slot > slot_count);
-
-       mas->offset = ++slot;
-       pivots = ma_pivots(mas_mn(mas), mt);
-       if (slot > 0)
-               mas->min = pivots[slot - 1] + 1;
-
-       if (slot <= slot_count)
-               mas->max = pivots[slot];
+       } while (mas->offset >= mas_data_end(mas));
 
+       mas->offset++;
        return true;
 }
 
@@ -6631,11 +6655,11 @@ static inline void *mas_first_entry(struct ma_state *mas, struct maple_node *mn,
        while (likely(!ma_is_leaf(mt))) {
                MT_BUG_ON(mas->tree, mte_dead_node(mas->node));
                slots = ma_slots(mn, mt);
-               pivots = ma_pivots(mn, mt);
-               max = pivots[0];
                entry = mas_slot(mas, slots, 0);
+               pivots = ma_pivots(mn, mt);
                if (unlikely(ma_dead_node(mn)))
                        return NULL;
+               max = pivots[0];
                mas->node = entry;
                mn = mas_mn(mas);
                mt = mte_node_type(mas->node);
@@ -6655,13 +6679,13 @@ static inline void *mas_first_entry(struct ma_state *mas, struct maple_node *mn,
        if (likely(entry))
                return entry;
 
-       pivots = ma_pivots(mn, mt);
-       mas->index = pivots[0] + 1;
        mas->offset = 1;
        entry = mas_slot(mas, slots, 1);
+       pivots = ma_pivots(mn, mt);
        if (unlikely(ma_dead_node(mn)))
                return NULL;
 
+       mas->index = pivots[0] + 1;
        if (mas->index > limit)
                goto none;