maple_tree: introduce mas_tree_parent() definition

Add a definition to shorten long code lines and clarify what the code is
doing.  Use the new definition to get the maple tree parent pointer from
the maple state where possible.

Link: https://lkml.kernel.org/r/20230804165951.2661157-5-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

lib/maple_tree.c

@@ -75,6 +75,7 @@
 #define MA_STATE_PREALLOC	4
 
 #define ma_parent_ptr(x) ((struct maple_pnode *)(x))
+#define mas_tree_parent(x) ((unsigned long)(x->tree) | MA_ROOT_PARENT)
 #define ma_mnode_ptr(x) ((struct maple_node *)(x))
 #define ma_enode_ptr(x) ((struct maple_enode *)(x))
 static struct kmem_cache *maple_node_cache;
@@ -1728,8 +1729,7 @@ static inline void mas_put_in_tree(struct ma_state *mas,
 	void __rcu **slots;
 
 	if (mte_is_root(mas->node)) {
-		mas_mn(mas)->parent = ma_parent_ptr(
-			      ((unsigned long)mas->tree | MA_ROOT_PARENT));
+		mas_mn(mas)->parent = ma_parent_ptr(mas_tree_parent(mas));
 		rcu_assign_pointer(mas->tree->ma_root, mte_mk_root(mas->node));
 		mas_set_height(mas);
 	} else {
@@ -2798,8 +2798,7 @@ static inline void mas_wmb_replace(struct ma_state *mas,
 static inline void mast_new_root(struct maple_subtree_state *mast,
 				 struct ma_state *mas)
 {
-	mas_mn(mast->l)->parent =
-		ma_parent_ptr(((unsigned long)mas->tree | MA_ROOT_PARENT));
+	mas_mn(mast->l)->parent = ma_parent_ptr(mas_tree_parent(mas));
 	if (!mte_dead_node(mast->orig_l->node) &&
 	    !mte_is_root(mast->orig_l->node)) {
 		do {
@@ -3661,8 +3660,7 @@ static inline int mas_root_expand(struct ma_state *mas, void *entry)
 	node = mas_pop_node(mas);
 	pivots = ma_pivots(node, type);
 	slots = ma_slots(node, type);
-	node->parent = ma_parent_ptr(
-		      ((unsigned long)mas->tree | MA_ROOT_PARENT));
+	node->parent = ma_parent_ptr(mas_tree_parent(mas));
 	mas->node = mt_mk_node(node, type);
 
 	if (mas->index) {
@@ -3938,8 +3936,7 @@ static inline int mas_new_root(struct ma_state *mas, void *entry)
 	node = mas_pop_node(mas);
 	pivots = ma_pivots(node, type);
 	slots = ma_slots(node, type);
-	node->parent = ma_parent_ptr(
-		      ((unsigned long)mas->tree | MA_ROOT_PARENT));
+	node->parent = ma_parent_ptr(mas_tree_parent(mas));
 	mas->node = mt_mk_node(node, type);
 	rcu_assign_pointer(slots[0], entry);
 	pivots[0] = mas->last;