From: Liam R. Howlett <Liam.Howlett@oracle.com>
Date: Wed, 24 Nov 2021 16:27:08 +0000 (-0500)
Subject: maple_tree: Don't record position in mas_split() and mas_spanning_reblance()
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=e7bc1041c706606d3c49501c4624d2e78cb1e78f;p=users%2Fjedix%2Flinux-maple.git

maple_tree: Don't record position in mas_split() and mas_spanning_reblance()

Just walk there in the end

Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
---

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 9cb5bfb7cc60..740ccbbb2a49 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -2625,8 +2625,7 @@ static inline void mast_new_root(struct maple_subtree_state *mast,
  */
 static inline void mast_cp_to_nodes(struct maple_subtree_state *mast,
 	struct maple_enode *left, struct maple_enode *middle,
-	struct maple_enode *right, unsigned char split, unsigned char mid_split,
-	struct ma_state *save)
+	struct maple_enode *right, unsigned char split, unsigned char mid_split)
 {
 	mast->l->node = mte_node_or_none(left);
 	mast->m->node = mte_node_or_none(middle);
@@ -2641,13 +2640,6 @@ static inline void mast_cp_to_nodes(struct maple_subtree_state *mast,
 		mab_mas_cp(mast->bn, 1 + split, mid_split, mast->m, true);
 		mast->m->min = mast->bn->pivot[split] + 1;
 		mast->m->max = mast->bn->pivot[mid_split];
-		if (!save->node &&
-		    (save->offset > split) && (save->offset < mid_split)) {
-			save->offset -= (split + 1);
-			save->node= mast->m->node;
-			save->min = mast->m->min;
-			save->max = mast->m->max;
-		}
 		split = mid_split;
 	}
 
@@ -2655,17 +2647,6 @@ static inline void mast_cp_to_nodes(struct maple_subtree_state *mast,
 		mab_mas_cp(mast->bn, 1 + split, mast->bn->b_end, mast->r, true);
 		mast->r->min = mast->bn->pivot[split] + 1;
 		mast->r->max = mast->bn->pivot[mast->bn->b_end];
-		if (!save->node && (save->offset > split)) {
-			save->offset -= (split + 1);
-			save->node= mast->r->node;
-			save->min = mast->r->min;
-			save->max = mast->r->max;
-		}
-	}
-	if (!save->node) {
-		save->node= mast->l->node;
-		save->min = mast->l->min;
-		save->max = mast->l->max;
 	}
 }
 
@@ -2738,6 +2719,75 @@ static inline void mast_setup_bnode_for_split(struct maple_subtree_state *mast)
 	mast->bn->type = mte_node_type(mast->orig_l->node);
 }
 
+
+static inline void *mtree_range_walk(struct ma_state *mas)
+{
+	unsigned long *pivots;
+	unsigned char offset;
+	struct maple_node *node;
+	struct maple_enode *next, *last;
+	enum maple_type type;
+	void __rcu **slots;
+	unsigned char end;
+	unsigned long max, min;
+	unsigned long prev_max, prev_min;
+
+	last = next = mas->node;
+	prev_min = min = mas->min;
+	max = mas->max;
+	do {
+		offset = 0;
+		last = next;
+		node = mte_to_node(next);
+		type = mte_node_type(next);
+		pivots = ma_pivots(node, type);
+		if (unlikely(ma_dead_node(node)))
+			goto dead_node;
+
+		end = ma_data_end(node, type, pivots, max);
+		if (pivots[offset] >= mas->index) {
+			prev_max = max;
+			prev_min = min;
+			max = pivots[offset];
+			goto next;
+		}
+
+		do {
+			offset++;
+		} while((offset < end) && (pivots[offset] < mas->index));
+
+		prev_min = min;
+		prev_max = max;
+		if (offset < mt_pivots[type] && pivots[offset])
+			max = pivots[offset];
+
+		if (offset)
+			min = pivots[offset - 1] + 1;
+
+		if (likely(offset > end) && pivots[offset]) {
+next:
+			max = pivots[offset];
+		}
+
+		slots = ma_slots(node, type);
+		next = mt_slot(mas->tree, slots, offset);
+		if (unlikely(ma_dead_node(node)))
+			goto dead_node;
+	} while (!ma_is_leaf(type));
+
+	mas->offset = offset;
+	mas->index = min;
+	mas->last = max;
+	mas->min = prev_min;
+	mas->max = prev_max;
+	mas->node = last;
+	return (void *) next;
+
+dead_node:
+	mas_reset(mas);
+	return NULL;
+}
+
 /*
  * mas_spanning_rebalance() - Rebalance across two nodes which may not be peers.
  * @mas: The starting maple state
@@ -2759,7 +2809,6 @@ static inline void mast_setup_bnode_for_split(struct maple_subtree_state *mast)
 static int mas_spanning_rebalance(struct ma_state *mas,
 		struct maple_subtree_state *mast, unsigned char count)
 {
-	struct ma_state restore;
 	unsigned char split, mid_split;
 	unsigned char slot = 0;
 	struct maple_enode *left = NULL, *middle = NULL, *right = NULL;
@@ -2785,8 +2834,6 @@ static int mas_spanning_rebalance(struct ma_state *mas,
 		if (!mast_sibling_rebalance_right(mast, false))
 			mast_cousin_rebalance_right(mast, false);
 	}
-	restore.node = NULL;
-	restore.offset = mas->offset;
 	mast->orig_l->depth = 0;
 
 	while (count--) {
@@ -2795,8 +2842,7 @@ static int mas_spanning_rebalance(struct ma_state *mas,
 					&mid_split);
 		mast_set_split_parents(mast, left, middle, right, split,
 				       mid_split);
-		mast_cp_to_nodes(mast, left, middle, right, split, mid_split,
-				 &restore);
+		mast_cp_to_nodes(mast, left, middle, right, split, mid_split);
 
 		/*
 		 * Copy data from next level in the tree to mast->bn from next
@@ -2870,10 +2916,7 @@ new_root:
 	mast->orig_l->alloc = mas->alloc;
 	*mas = *mast->orig_l;
 	mas_wmb_replace(mas, &free, &destroy);
-	mas->offset = restore.offset;
-	mas->min = restore.min;
-	mas->max = restore.max;
-	mas->node = restore.node;
+	mtree_range_walk(mas);
 	return mast->bn->b_end;
 }
 
@@ -3155,7 +3198,7 @@ static inline void mast_fill_bnode(struct maple_subtree_state *mast,
  * @split: The location to split the big node
  */
 static inline void mast_split_data(struct maple_subtree_state *mast,
-	   struct ma_state *mas, unsigned char split, struct ma_state *save)
+	   struct ma_state *mas, unsigned char split)
 {
 	unsigned char p_slot;
 
@@ -3165,24 +3208,14 @@ static inline void mast_split_data(struct maple_subtree_state *mast,
 	mast->l->offset = mte_parent_slot(mas->node);
 	mast->l->max = mast->bn->pivot[split];
 	mast->r->min = mast->l->max + 1;
-	if (!mte_is_leaf(mas->node)) {
-		p_slot = mast->orig_l->offset;
-		mas_set_split_parent(mast->orig_l, mast->l->node,
-				     mast->r->node, &p_slot, split);
-		mas_set_split_parent(mast->orig_r, mast->l->node,
-				     mast->r->node, &p_slot, split);
-	} else {
-		if (save->offset > split) {
-			save->node = mast->r->node;
-			save->min = mast->r->min;
-			save->max = mast->r->max;
-			save->offset -= (split + 1);
-		} else {
-			save->node = mast->l->node;
-			save->min = mast->l->min;
-			save->max = mast->l->max;
-		}
-	}
+	if (mte_is_leaf(mas->node))
+	    return;
+
+	p_slot = mast->orig_l->offset;
+	mas_set_split_parent(mast->orig_l, mast->l->node, mast->r->node,
+			     &p_slot, split);
+	mas_set_split_parent(mast->orig_r, mast->l->node, mast->r->node,
+			     &p_slot, split);
 }
 
 /*
@@ -3198,8 +3231,7 @@ static inline void mast_split_data(struct maple_subtree_state *mast,
  * Return: True if pushed, false otherwise.
  */
 static inline bool mas_push_data(struct ma_state *mas, int height,
-				 struct maple_subtree_state *mast, bool left,
-				 struct ma_state *save)
+				 struct maple_subtree_state *mast, bool left)
 {
 	unsigned char slot_total = mast->bn->b_end;
 	unsigned char end, space, split;
@@ -3232,8 +3264,6 @@ static inline bool mas_push_data(struct ma_state *mas, int height,
 		mab_shift_right(mast->bn, end + 1);
 		mas_mab_cp(&tmp_mas, 0, end, mast->bn, 0);
 		mast->bn->b_end = slot_total + 1;
-		if (!save->node)
-			save->offset = mas->offset + end + 1;
 	} else {
 		mas_mab_cp(&tmp_mas, 0, end, mast->bn, mast->bn->b_end);
 	}
@@ -3258,7 +3288,7 @@ static inline bool mas_push_data(struct ma_state *mas, int height,
 	if (left)
 		mast->orig_l->offset += end + 1;
 
-	mast_split_data(mast, mas, split, save);
+	mast_split_data(mast, mas, split);
 	mast_fill_bnode(mast, mas, 2);
 	_mas_split_final_node(mast, mas, height + 1);
 	return true;
@@ -3276,7 +3306,6 @@ static int mas_split(struct ma_state *mas, struct maple_big_node *b_node)
 	struct maple_subtree_state mast;
 	int height = 0;
 	unsigned char mid_split, split = 0;
-	struct ma_state restore;
 
 	MA_STATE(l_mas, mas->tree, mas->index, mas->last);
 	MA_STATE(r_mas, mas->tree, mas->index, mas->last);
@@ -3297,8 +3326,6 @@ static int mas_split(struct ma_state *mas, struct maple_big_node *b_node)
 	mast.orig_r = &prev_r_mas;
 	mast.free = &mat;
 	mast.bn = b_node;
-	restore.node = NULL;
-	restore.offset = mas->offset;
 
 	while (height++ <= mas->depth) {
 		if (mas_split_final_node(&mast, mas, height))
@@ -3308,15 +3335,15 @@ static int mas_split(struct ma_state *mas, struct maple_big_node *b_node)
 		l_mas.node = mas_new_ma_node(mas, b_node);
 		r_mas.node = mas_new_ma_node(mas, b_node);
 		/* Try to push left. */
-		if (mas_push_data(mas, height, &mast, true, &restore))
+		if (mas_push_data(mas, height, &mast, true))
 			break;
 
 		/* Try to push right. */
-		if (mas_push_data(mas, height, &mast, false, &restore))
+		if (mas_push_data(mas, height, &mast, false))
 			break;
 
 		split = mab_calc_split(mas, b_node, &mid_split);
-		mast_split_data(&mast, mas, split, &restore);
+		mast_split_data(&mast, mas, split);
 		/*
 		 * Usually correct, mab_mas_cp in the above call overwrites
 		 * r->max.
@@ -3331,10 +3358,7 @@ static int mas_split(struct ma_state *mas, struct maple_big_node *b_node)
 	mat_add(mast.free, mas->node);
 	mas->node = l_mas.node;
 	mas_wmb_replace(mas, mast.free, NULL);
-	mas->offset = restore.offset;
-	mas->min = restore.min;
-	mas->max = restore.max;
-	mas->node = restore.node;
+	mtree_range_walk(mas);
 	return 1;
 }
 
@@ -3626,73 +3650,6 @@ static inline void mas_extend_spanning_null(struct ma_wr_state *l_wr_mas,
 	}
 }
 
-static inline void *mtree_range_walk(struct ma_state *mas)
-{
-	unsigned long *pivots;
-	unsigned char offset;
-	struct maple_node *node;
-	struct maple_enode *next, *last;
-	enum maple_type type;
-	void __rcu **slots;
-	unsigned char end;
-	unsigned long max, min;
-	unsigned long prev_max, prev_min;
-
-	last = next = mas->node;
-	prev_min = min = mas->min;
-	max = mas->max;
-	do {
-		offset = 0;
-		last = next;
-		node = mte_to_node(next);
-		type = mte_node_type(next);
-		pivots = ma_pivots(node, type);
-		if (unlikely(ma_dead_node(node)))
-			goto dead_node;
-
-		end = ma_data_end(node, type, pivots, max);
-		if (pivots[offset] >= mas->index) {
-			prev_max = max;
-			prev_min = min;
-			max = pivots[offset];
-			goto next;
-		}
-
-		do {
-			offset++;
-		} while((offset < end) && (pivots[offset] < mas->index));
-
-		prev_min = min;
-		prev_max = max;
-		if (offset < mt_pivots[type] && pivots[offset])
-			max = pivots[offset];
-
-		if (offset)
-			min = pivots[offset - 1] + 1;
-
-		if (likely(offset > end) && pivots[offset]) {
-next:
-			max = pivots[offset];
-		}
-
-		slots = ma_slots(node, type);
-		next = mt_slot(mas->tree, slots, offset);
-		if (unlikely(ma_dead_node(node)))
-			goto dead_node;
-	} while (!ma_is_leaf(type));
-
-	mas->offset = offset;
-	mas->index = min;
-	mas->last = max;
-	mas->min = prev_min;
-	mas->max = prev_max;
-	mas->node = last;
-	return (void *) next;
-
-dead_node:
-	mas_reset(mas);
-	return NULL;
-}
 
 static inline void *mas_state_walk(struct ma_state *mas)
 {