From: Liam R. Howlett <Liam.Howlett@Oracle.com>
Date: Wed, 31 Jul 2019 18:52:04 +0000 (-0400)
Subject: maple_tree: mt_for_each implementation
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=afb62484530cb0ae2ace7b556ff56550f9c2e404;p=users%2Fjedix%2Flinux-maple.git

maple_tree: mt_for_each implementation

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

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 050675c7ce28..e88a09faaabf 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -22,6 +22,9 @@
  * @entry: Entry retrieved from the tree
  * @max: maximum index to retrieve from the tree
  *
+ * When returned, mas->index and mas->last will hold the entire range for the
+ * entry.
+ *
  * Note: may return the zero entry.
  *
  */
@@ -29,7 +32,7 @@
 	while ((entry = mas_find(mas, max)) != NULL)
 
 /**
- * mt_for_each - Iterate over a range of the tree.
+ * mt_for_each - Searches for an entry starting at index until max.
  *
  *
  *
@@ -37,7 +40,9 @@
  *
  *
  */
-#define mt_for_each(tree, entry, index, last, max) \
+#define mt_for_each(tree, entry, index, max) \
+	for (entry = mt_find(mt, index, max); \
+	     entry; entry = mt_find_after(mt, &index, max))
 
 
 
@@ -2202,6 +2207,7 @@ mas_next_nentry (struct ma_state *mas, unsigned long max, unsigned long *piv)
 	unsigned char slot = ma_get_slot(mas);
 	unsigned char count = mt_slot_count(mas->node);
 	void *entry;
+	bool ret = false;
 
 	while (slot < count) {
 		pivot = ma_get_safe_pivot(mas, slot);
@@ -2214,8 +2220,10 @@ mas_next_nentry (struct ma_state *mas, unsigned long max, unsigned long *piv)
 		/* Valid pivot */;
 
 		entry = ma_get_rcu_slot(mas->node, slot);
-		if (entry)
+		if (entry) {
+			ret = true;
 			break;
+		}
 
 		/* Ran over the limit, this is was the last slot to try */
 		if (pivot >= max)
@@ -2224,7 +2232,7 @@ mas_next_nentry (struct ma_state *mas, unsigned long max, unsigned long *piv)
 		slot++;
 	}
 	ma_set_slot(mas, slot);
-	return true;
+	return ret;
 
 no_entry:
 	return false;
@@ -2727,12 +2735,76 @@ not_found:
 
 }
 
-void *mt_find_after(struct ma_state *mas, unsigned long max)
+/* mt_find() - Search from start up until an entry is found.
+ *
+ * Note: Does not return the zero entry.
+ * returns an entry.
+ */
+static inline void *mt_find(struct maple_tree *mt, unsigned long start,
+		unsigned long max)
 {
-	void *entry = mas_find(mas, max);
+	MA_STATE(mas, mt, start, start);
+	unsigned char slot;
+	void *entry = NULL;
+
+	rcu_read_lock();
+	_mas_walk(&mas);
+	slot = ma_get_slot(&mas);
+	if (slot != MAPLE_NODE_SLOTS)
+		entry = ma_get_rcu_slot(mas.node, slot);
+
 	if (xa_is_zero(entry))
-		return NULL;
+		entry = NULL;
+
+	if (entry)
+		goto done;
+
+retry:
+	mas_next_entry(&mas, max);
+	if (mas.node == MAS_NONE)
+		goto done;
+
+	slot = ma_get_slot(&mas);
+	entry = ma_get_rcu_slot(mas.node, slot);
+	if (xa_is_zero(entry))
+		goto retry;
+
+done:
+	rcu_read_unlock();
+
+	return entry;
+}
+
+/* mt_find_after() - Search up from the entry of index until an entry is
+ * found.
+ *
+ * Modifies index and last to point to the newly found range.
+ */
+static inline void *mt_find_after(struct maple_tree *mt, unsigned long *index,
+		unsigned long max)
+{
+	MA_STATE(mas, mt, *index, *index);
+	unsigned char slot;
+	void *entry = NULL;
+
+	rcu_read_lock();
+	_mas_walk(&mas);
+retry:
+	ma_set_slot(&mas, ma_get_slot(&mas) + 1);
+	mas_next_entry(&mas, max);
+	if (mas.node == MAS_NONE)
+		goto done;
+
+	slot = ma_get_slot(&mas);
+	entry = ma_get_rcu_slot(mas.node, slot);
+	if (xa_is_zero(entry))
+		goto retry;
+
+	*index = ma_get_safe_pivot(&mas, slot);
+done:
+	rcu_read_unlock();
 	return entry;
+
 }
 static inline void ma_inactive_insert(struct ma_state *mas, void *entry);
 static inline int mas_replace_tree(struct ma_state *mas, void *new_entry)
diff --git a/lib/test_maple_tree.c b/lib/test_maple_tree.c
index ea40c425fda0..103ac70cf239 100644
--- a/lib/test_maple_tree.c
+++ b/lib/test_maple_tree.c
@@ -364,6 +364,8 @@ static noinline void check_find(struct maple_tree *mt)
 {
 	unsigned long val = 0;
 	unsigned long count = 20;
+	unsigned long max;
+	unsigned long index = 0;
 	void *entry;
 	MA_STATE(mas, mt, 0, 0);
 
@@ -410,6 +412,12 @@ static noinline void check_find(struct maple_tree *mt)
 			val = 1;
 	}
 
+	max = 300; // A value big enough to include XA_ZERO_ENTRY at 64.
+	mt_for_each(mt, entry, index, max) {
+		MT_BUG_ON(mt, xa_mk_value(val) != entry);
+	}
+
+
 }
 static noinline void check_alloc_rev_range(struct maple_tree *mt)
 {