1 files changed, 96 insertions, 92 deletions

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 72c89eb03393..b1db0bd71aed 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -824,6 +824,11 @@ static inline void *mt_slot(const struct maple_tree *mt,
 	return rcu_dereference_check(slots[offset], mt_locked(mt));
 }
 
+static inline void *mt_slot_locked(struct maple_tree *mt, void __rcu **slots,
+				   unsigned char offset)
+{
+	return rcu_dereference_protected(slots[offset], mt_locked(mt));
+}
 /*
  * mas_slot_locked() - Get the slot value when holding the maple tree lock.
  * @mas: The maple state
@@ -835,7 +840,7 @@ static inline void *mt_slot(const struct maple_tree *mt,
 static inline void *mas_slot_locked(struct ma_state *mas, void __rcu **slots,
 				       unsigned char offset)
 {
-	return rcu_dereference_protected(slots[offset], mt_locked(mas->tree));
+	return mt_slot_locked(mas->tree, slots, offset);
 }
 
 /*
@@ -907,34 +912,35 @@ static inline void ma_set_meta(struct maple_node *mn, enum maple_type mt,
 }
 
 /*
- * mas_clear_meta() - clear the metadata information of a node, if it exists
- * @mas: The maple state
+ * mt_clear_meta() - clear the metadata information of a node, if it exists
+ * @mt: The maple tree
  * @mn: The maple node
- * @mt: The maple node type
+ * @type: The maple node type
  * @offset: The offset of the highest sub-gap in this node.
  * @end: The end of the data in this node.
  */
-static inline void mas_clear_meta(struct ma_state *mas, struct maple_node *mn,
-				  enum maple_type mt)
+static inline void mt_clear_meta(struct maple_tree *mt, struct maple_node *mn,
+				  enum maple_type type)
 {
 	struct maple_metadata *meta;
 	unsigned long *pivots;
 	void __rcu **slots;
 	void *next;
 
-	switch (mt) {
+	switch (type) {
 	case maple_range_64:
 		pivots = mn->mr64.pivot;
 		if (unlikely(pivots[MAPLE_RANGE64_SLOTS - 2])) {
 			slots = mn->mr64.slot;
-			next = mas_slot_locked(mas, slots,
-					       MAPLE_RANGE64_SLOTS - 1);
-			if (unlikely((mte_to_node(next) && mte_node_type(next))))
-				return; /* The last slot is a node, no metadata */
+			next = mt_slot_locked(mt, slots,
+					      MAPLE_RANGE64_SLOTS - 1);
+			if (unlikely((mte_to_node(next) &&
+				      mte_node_type(next))))
+				return; /* no metadata, could be node */
 		}
 		fallthrough;
 	case maple_arange_64:
-		meta = ma_meta(mn, mt);
+		meta = ma_meta(mn, type);
 		break;
 	default:
 		return;
@@ -5483,7 +5489,7 @@ no_gap:
 }
 
 /*
- * mas_dead_leaves() - Mark all leaves of a node as dead.
+ * mte_dead_leaves() - Mark all leaves of a node as dead.
  * @mas: The maple state
  * @slots: Pointer to the slot array
  * @type: The maple node type
@@ -5493,16 +5499,16 @@ no_gap:
  * Return: The number of leaves marked as dead.
  */
 static inline
-unsigned char mas_dead_leaves(struct ma_state *mas, void __rcu **slots,
-			      enum maple_type mt)
+unsigned char mte_dead_leaves(struct maple_enode *enode, struct maple_tree *mt,
+			      void __rcu **slots)
 {
 	struct maple_node *node;
 	enum maple_type type;
 	void *entry;
 	int offset;
 
-	for (offset = 0; offset < mt_slots[mt]; offset++) {
-		entry = mas_slot_locked(mas, slots, offset);
+	for (offset = 0; offset < mt_slot_count(enode); offset++) {
+		entry = mt_slot(mt, slots, offset);
 		type = mte_node_type(entry);
 		node = mte_to_node(entry);
 		/* Use both node and type to catch LE & BE metadata */
@@ -5517,162 +5523,160 @@ unsigned char mas_dead_leaves(struct ma_state *mas, void __rcu **slots,
 	return offset;
 }
 
-static void __rcu **mas_dead_walk(struct ma_state *mas, unsigned char offset)
+/**
+ * mte_dead_walk() - Walk down a dead tree to just before the leaves
+ * @enode: The maple encoded node
+ * @offset: The starting offset
+ *
+ * Note: This can only be used from the RCU callback context.
+ */
+static void __rcu **mte_dead_walk(struct maple_enode **enode, unsigned char offset)
 {
-	struct maple_node *next;
+	struct maple_node *node, *next;
 	void __rcu **slots = NULL;
 
-	next = mas_mn(mas);
+	next = mte_to_node(*enode);
 	do {
-		mas->node = mt_mk_node(next, next->type);
-		slots = ma_slots(next, next->type);
-		next = mas_slot_locked(mas, slots, offset);
+		*enode = ma_enode_ptr(next);
+		node = mte_to_node(*enode);
+		slots = ma_slots(node, node->type);
+		next = rcu_dereference_protected(slots[offset],
+					lock_is_held(&rcu_callback_map));
 		offset = 0;
 	} while (!ma_is_leaf(next->type));
 
 	return slots;
 }
 
+/**
+ * mt_free_walk() - Walk & free a tree in the RCU callback context
+ * @head: The RCU head that's within the node.
+ *
+ * Note: This can only be used from the RCU callback context.
+ */
 static void mt_free_walk(struct rcu_head *head)
 {
 	void __rcu **slots;
 	struct maple_node *node, *start;
-	struct maple_tree mt;
+	struct maple_enode *enode;
 	unsigned char offset;
 	enum maple_type type;
-	MA_STATE(mas, &mt, 0, 0);
 
 	node = container_of(head, struct maple_node, rcu);
 
 	if (ma_is_leaf(node->type))
 		goto free_leaf;
 
-	mt_init_flags(&mt, node->ma_flags);
-	mas_lock(&mas);
 	start = node;
-	mas.node = mt_mk_node(node, node->type);
-	slots = mas_dead_walk(&mas, 0);
-	node = mas_mn(&mas);
+	enode = mt_mk_node(node, node->type);
+	slots = mte_dead_walk(&enode, 0);
+	node = mte_to_node(enode);
 	do {
 		mt_free_bulk(node->slot_len, slots);
 		offset = node->parent_slot + 1;
-		mas.node = node->piv_parent;
-		if (mas_mn(&mas) == node)
-			goto start_slots_free;
-
-		type = mte_node_type(mas.node);
-		slots = ma_slots(mte_to_node(mas.node), type);
-		if ((offset < mt_slots[type]) && (slots[offset]))
-			slots = mas_dead_walk(&mas, offset);
-
-		node = mas_mn(&mas);
+		enode = node->piv_parent;
+		if (mte_to_node(enode) == node)
+			goto free_leaf;
+
+		type = mte_node_type(enode);
+		slots = ma_slots(mte_to_node(enode), type);
+		if ((offset < mt_slots[type]) &&
+		    rcu_dereference_protected(slots[offset],
+					      lock_is_held(&rcu_callback_map)))
+			slots = mte_dead_walk(&enode, offset);
+		node = mte_to_node(enode);
 	} while ((node != start) || (node->slot_len < offset));
 
 	slots = ma_slots(node, node->type);
 	mt_free_bulk(node->slot_len, slots);
 
-start_slots_free:
-	mas_unlock(&mas);
 free_leaf:
 	mt_free_rcu(&node->rcu);
 }
 
-static inline void __rcu **mas_destroy_descend(struct ma_state *mas,
-			struct maple_enode *prev, unsigned char offset)
+static inline void __rcu **mte_destroy_descend(struct maple_enode **enode,
+	struct maple_tree *mt, struct maple_enode *prev, unsigned char offset)
 {
 	struct maple_node *node;
-	struct maple_enode *next = mas->node;
+	struct maple_enode *next = *enode;
 	void __rcu **slots = NULL;
+	enum maple_type type;
+	unsigned char next_offset = 0;
 
 	do {
-		mas->node = next;
-		node = mas_mn(mas);
-		slots = ma_slots(node, mte_node_type(mas->node));
-		next = mas_slot_locked(mas, slots, 0);
-		if ((mte_dead_node(next))) {
-			mte_to_node(next)->type = mte_node_type(next);
-			next = mas_slot_locked(mas, slots, 1);
-		}
+		*enode = next;
+		node = mte_to_node(*enode);
+		type = mte_node_type(*enode);
+		slots = ma_slots(node, type);
+		next = mt_slot_locked(mt, slots, next_offset);
+		if ((mte_dead_node(next)))
+			next = mt_slot_locked(mt, slots, ++next_offset);
 
-		mte_set_node_dead(mas->node);
-		node->type = mte_node_type(mas->node);
-		mas_clear_meta(mas, node, node->type);
+		mte_set_node_dead(*enode);
+		node->type = type;
 		node->piv_parent = prev;
 		node->parent_slot = offset;
-		offset = 0;
-		prev = mas->node;
+		offset = next_offset;
+		next_offset = 0;
+		prev = *enode;
 	} while (!mte_is_leaf(next));
 
 	return slots;
 }
 
-static void mt_destroy_walk(struct maple_enode *enode, unsigned char ma_flags,
+static void mt_destroy_walk(struct maple_enode *enode, struct maple_tree *mt,
 			    bool free)
 {
 	void __rcu **slots;
 	struct maple_node *node = mte_to_node(enode);
 	struct maple_enode *start;
-	struct maple_tree mt;
-
-	MA_STATE(mas, &mt, 0, 0);
 
-	mas.node = enode;
 	if (mte_is_leaf(enode)) {
 		node->type = mte_node_type(enode);
 		goto free_leaf;
 	}
 
-	ma_flags &= ~MT_FLAGS_LOCK_MASK;
-	mt_init_flags(&mt, ma_flags);
-	mas_lock(&mas);
-
-	mte_to_node(enode)->ma_flags = ma_flags;
 	start = enode;
-	slots = mas_destroy_descend(&mas, start, 0);
-	node = mas_mn(&mas);
+	slots = mte_destroy_descend(&enode, mt, start, 0);
+	node = mte_to_node(enode); // Updated in the above call.
 	do {
 		enum maple_type type;
 		unsigned char offset;
 		struct maple_enode *parent, *tmp;
 
-		node->type = mte_node_type(mas.node);
-		node->slot_len = mas_dead_leaves(&mas, slots, node->type);
+		node->slot_len = mte_dead_leaves(enode, mt, slots);
 		if (free)
 			mt_free_bulk(node->slot_len, slots);
 		offset = node->parent_slot + 1;
-		mas.node = node->piv_parent;
-		if (mas_mn(&mas) == node)
-			goto start_slots_free;
+		enode = node->piv_parent;
+		if (mte_to_node(enode) == node)
+			goto free_leaf;
 
-		type = mte_node_type(mas.node);
-		slots = ma_slots(mte_to_node(mas.node), type);
+		type = mte_node_type(enode);
+		slots = ma_slots(mte_to_node(enode), type);
 		if (offset >= mt_slots[type])
 			goto next;
 
-		tmp = mas_slot_locked(&mas, slots, offset);
+		tmp = mt_slot_locked(mt, slots, offset);
 		if (mte_node_type(tmp) && mte_to_node(tmp)) {
-			parent = mas.node;
-			mas.node = tmp;
-			slots = mas_destroy_descend(&mas, parent, offset);
+			parent = enode;
+			enode = tmp;
+			slots = mte_destroy_descend(&enode, mt, parent, offset);
 		}
 next:
-		node = mas_mn(&mas);
-	} while (start != mas.node);
+		node = mte_to_node(enode);
+	} while (start != enode);
 
-	node = mas_mn(&mas);
-	node->type = mte_node_type(mas.node);
-	node->slot_len = mas_dead_leaves(&mas, slots, node->type);
+	node = mte_to_node(enode);
+	node->slot_len = mte_dead_leaves(enode, mt, slots);
 	if (free)
 		mt_free_bulk(node->slot_len, slots);
 
-start_slots_free:
-	mas_unlock(&mas);
-
 free_leaf:
 	if (free)
 		mt_free_rcu(&node->rcu);
 	else
-		mas_clear_meta(&mas, node, node->type);
+		mt_clear_meta(mt, node, node->type);
 }
 
 /*
@@ -5688,10 +5692,10 @@ static inline void mte_destroy_walk(struct maple_enode *enode,
 	struct maple_node *node = mte_to_node(enode);
 
 	if (mt_in_rcu(mt)) {
-		mt_destroy_walk(enode, mt->ma_flags, false);
+		mt_destroy_walk(enode, mt, false);
 		call_rcu(&node->rcu, mt_free_walk);
 	} else {
-		mt_destroy_walk(enode, mt->ma_flags, true);
+		mt_destroy_walk(enode, mt, true);
 	}
 }