[PATCH v3 30/30] maple_tree: Clean up mas_wr_node_store()

["Liam R. Howlett" <Liam.Howlett@oracle.com>]

The new_end does not need to be passed in as the data is already being
checked.  This allows for other areas to skip getting the node new_end
in the calling function.

The type was incorrectly void * instead of void __rcu *, which isn't an
issue but is technically incorrect.

Move the variable assignment to after the declarations to clean up the
initial setup.

Ensure there is something to copy before calling memcpy().

Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
---
 lib/maple_tree.c | 42 ++++++++++++++++++++++++++----------------
 1 file changed, 26 insertions(+), 16 deletions(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index c9c63246f721c..af4554a23881d 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -3122,20 +3122,28 @@ static void mas_wr_spanning_store(struct ma_wr_state *wr_mas)
  *
  * Attempts to reuse the node, but may allocate.
  */
-static inline void mas_wr_node_store(struct ma_wr_state *wr_mas,
-				     unsigned char new_end)
+static inline void mas_wr_node_store(struct ma_wr_state *wr_mas)
 {
-	struct ma_state *mas = wr_mas->mas;
-	void __rcu **dst_slots;
-	unsigned long *dst_pivots;
-	unsigned char dst_offset, offset_end = wr_mas->offset_end;
+	unsigned char dst_offset, offset_end;
+	unsigned char copy_size, node_pivots;
 	struct maple_node reuse, *newnode;
-	unsigned char copy_size, node_pivots = mt_pivots[wr_mas->type];
-	bool in_rcu = mt_in_rcu(mas->tree);
-	unsigned char height = mas_mt_height(mas);
+	unsigned long *dst_pivots;
+	void __rcu **dst_slots;
+	unsigned char new_end;
+	struct ma_state *mas;
+	bool in_rcu;
 
-	if (mas->last == wr_mas->end_piv)
+	mas = wr_mas->mas;
+	trace_ma_op(TP_FCT, mas);
+	in_rcu = mt_in_rcu(mas->tree);
+	offset_end = wr_mas->offset_end;
+	node_pivots = mt_pivots[wr_mas->type];
+	/* Assume last adds an entry */
+	new_end = mas->end + 1 - offset_end + mas->offset;
+	if (mas->last == wr_mas->end_piv) {
 		offset_end++; /* don't copy this offset */
+		new_end--;
+	}
 
 	/* set up node. */
 	if (in_rcu) {
@@ -3149,13 +3157,16 @@ static inline void mas_wr_node_store(struct ma_wr_state *wr_mas,
 	dst_pivots = ma_pivots(newnode, wr_mas->type);
 	dst_slots = ma_slots(newnode, wr_mas->type);
 	/* Copy from start to insert point */
-	memcpy(dst_pivots, wr_mas->pivots, sizeof(unsigned long) * mas->offset);
-	memcpy(dst_slots, wr_mas->slots, sizeof(void *) * mas->offset);
+	if (mas->offset) {
+		memcpy(dst_pivots, wr_mas->pivots, sizeof(unsigned long) * mas->offset);
+		memcpy(dst_slots, wr_mas->slots, sizeof(void __rcu *) * mas->offset);
+	}
 
 	/* Handle insert of new range starting after old range */
 	if (wr_mas->r_min < mas->index) {
 		rcu_assign_pointer(dst_slots[mas->offset], wr_mas->content);
 		dst_pivots[mas->offset++] = mas->index - 1;
+		new_end++;
 	}
 
 	/* Store the new entry and range end. */
@@ -3174,7 +3185,7 @@ static inline void mas_wr_node_store(struct ma_wr_state *wr_mas,
 	/* Copy to the end of node if necessary. */
 	copy_size = mas->end - offset_end + 1;
 	memcpy(dst_slots + dst_offset, wr_mas->slots + offset_end,
-	       sizeof(void *) * copy_size);
+	       sizeof(void __rcu *) * copy_size);
 	memcpy(dst_pivots + dst_offset, wr_mas->pivots + offset_end,
 	       sizeof(unsigned long) * (copy_size - 1));
 
@@ -3187,7 +3198,7 @@ static inline void mas_wr_node_store(struct ma_wr_state *wr_mas,
 		struct maple_enode *old_enode = mas->node;
 
 		mas->node = mt_mk_node(newnode, wr_mas->type);
-		mas_replace_node(mas, old_enode, height);
+		mas_replace_node(mas, old_enode, mas_mt_height(mas));
 	} else {
 		memcpy(wr_mas->node, newnode, sizeof(struct maple_node));
 	}
@@ -3503,7 +3514,6 @@ static void mas_wr_rebalance(struct ma_wr_state *wr_mas)
 static inline void mas_wr_store_entry(struct ma_wr_state *wr_mas)
 {
 	struct ma_state *mas = wr_mas->mas;
-	unsigned char new_end = mas_wr_new_end(wr_mas);
 
 	switch (mas->store_type) {
 	case wr_exact_fit:
@@ -3518,7 +3528,7 @@ static inline void mas_wr_store_entry(struct ma_wr_state *wr_mas)
 		mas_wr_slot_store(wr_mas);
 		break;
 	case wr_node_store:
-		mas_wr_node_store(wr_mas, new_end);
+		mas_wr_node_store(wr_mas);
 		break;
 	case wr_spanning_store:
 		mas_wr_spanning_store(wr_mas);
-- 
2.47.3