1 files changed, 24 insertions, 17 deletions

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index df352f6ccc24..5a976393c9ae 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -323,14 +323,19 @@ static inline void *mte_safe_root(const struct maple_enode *node)
 	return (void *)((unsigned long)node & ~MAPLE_ROOT_NODE);
 }
 
-static inline void mte_set_full(const struct maple_enode *node)
+static inline void *mte_set_full(const struct maple_enode *node)
 {
-	node = (void *)((unsigned long)node & ~MAPLE_ENODE_NULL);
+	return (void *)((unsigned long)node & ~MAPLE_ENODE_NULL);
 }
 
-static inline void mte_clear_full(const struct maple_enode *node)
+static inline void *mte_clear_full(const struct maple_enode *node)
 {
-	node = (void *)((unsigned long)node | MAPLE_ENODE_NULL);
+	return (void *)((unsigned long)node | MAPLE_ENODE_NULL);
+}
+
+static inline bool mte_has_null(const struct maple_enode *node)
+{
+	return (unsigned long)node & MAPLE_ENODE_NULL;
 }
 
 static inline bool ma_is_root(struct maple_node *node)
@@ -665,12 +670,13 @@ static inline unsigned long mte_pivot(const struct maple_enode *mn,
 				 unsigned char piv)
 {
 	struct maple_node *node = mte_to_node(mn);
+	enum maple_type type = mte_node_type(mn);
 
-	if (piv >= mt_pivots[piv]) {
+	if (piv >= mt_pivots[type]) {
 		WARN_ON(1);
 		return 0;
 	}
-	switch (mte_node_type(mn)) {
+	switch (type) {
 	case maple_arange_64:
 		return node->ma64.pivot[piv];
 	case maple_range_64:
@@ -2989,7 +2995,9 @@ static int mas_spanning_rebalance(struct ma_state *mas,
 	mast->free = &free;
 	mast->destroy = &destroy;
 	l_mas.node = r_mas.node = m_mas.node = MAS_NONE;
-	if (!(mast->orig_l->min && mast->orig_r->max == ULONG_MAX) &&
+
+	/* Check if this is not root and has sufficient data.  */
+	if (((mast->orig_l->min != 0) || (mast->orig_r->max != ULONG_MAX)) &&
 	    unlikely(mast->bn->b_end <= mt_min_slots[mast->bn->type]))
 		mast_spanning_rebalance(mast);
 
@@ -4880,7 +4888,7 @@ static bool mas_rev_awalk(struct ma_state *mas, unsigned long size)
 	unsigned long *pivots, *gaps;
 	void __rcu **slots;
 	unsigned long gap = 0;
-	unsigned long max, min, index;
+	unsigned long max, min;
 	unsigned char offset;
 
 	if (unlikely(mas_is_err(mas)))
@@ -4902,8 +4910,7 @@ static bool mas_rev_awalk(struct ma_state *mas, unsigned long size)
 		min = mas_safe_min(mas, pivots, --offset);
 
 	max = mas_safe_pivot(mas, pivots, offset, type);
-	index = mas->index;
-	while (index <= max) {
+	while (mas->index <= max) {
 		gap = 0;
 		if (gaps)
 			gap = gaps[offset];
@@ -4934,10 +4941,8 @@ static bool mas_rev_awalk(struct ma_state *mas, unsigned long size)
 		min = mas_safe_min(mas, pivots, offset);
 	}
 
-	if (unlikely(index > max)) {
-		mas_set_err(mas, -EBUSY);
-		return false;
-	}
+	if (unlikely((mas->index > max) || (size - 1 > max - mas->index)))
+		goto no_space;
 
 	if (unlikely(ma_is_leaf(type))) {
 		mas->offset = offset;
@@ -4954,9 +4959,11 @@ static bool mas_rev_awalk(struct ma_state *mas, unsigned long size)
 	return false;
 
 ascend:
-	if (mte_is_root(mas->node))
-		mas_set_err(mas, -EBUSY);
+	if (!mte_is_root(mas->node))
+		return false;
 
+no_space:
+	mas_set_err(mas, -EBUSY);
 	return false;
 }
 
@@ -6057,7 +6064,7 @@ void *mas_find_rev(struct ma_state *mas, unsigned long min)
 	if (mas->index < min)
 		return NULL;
 
-	/* Retries on dead nodes handled by mas_next_entry */
+	/* Retries on dead nodes handled by mas_prev_entry */
 	return mas_prev_entry(mas, min);
 }
 EXPORT_SYMBOL_GPL(mas_find_rev);