switchdev: introduce transaction item queue for attr_set and obj_add

Now, the memory allocation in prepare/commit state is done separatelly
in each driver (rocker). Introduce the similar mechanism in generic
switchdev code, in form of queue. That can be used not only for memory
allocations, but also for different items. Abort item destruction
is handled as well.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 102 insertions, 15 deletions

diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 7f50b7443402..ac76fd15ad8b 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -456,7 +456,8 @@ static int dsa_slave_stp_update(struct net_device *dev, u8 state)
 }
 
 static int dsa_slave_port_attr_set(struct net_device *dev,
-				   struct switchdev_attr *attr)
+				   struct switchdev_attr *attr,
+				   struct switchdev_trans *trans)
 {
 	int ret = 0;
 
@@ -474,7 +475,8 @@ static int dsa_slave_port_attr_set(struct net_device *dev,
 }
 
 static int dsa_slave_port_obj_add(struct net_device *dev,
-				  struct switchdev_obj *obj)
+				  struct switchdev_obj *obj,
+				  struct switchdev_trans *trans)
 {
 	int err;
 
diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c
index df5a5446ff4c..35e2967ffa18 100644
--- a/net/switchdev/switchdev.c
+++ b/net/switchdev/switchdev.c
@@ -1,6 +1,6 @@
 /*
  * net/switchdev/switchdev.c - Switch device API
- * Copyright (c) 2014 Jiri Pirko <jiri@resnulli.us>
+ * Copyright (c) 2014-2015 Jiri Pirko <jiri@resnulli.us>
  * Copyright (c) 2014-2015 Scott Feldman <sfeldma@gmail.com>
  *
  * This program is free software; you can redistribute it and/or modify
@@ -16,10 +16,83 @@
 #include <linux/notifier.h>
 #include <linux/netdevice.h>
 #include <linux/if_bridge.h>
+#include <linux/list.h>
 #include <net/ip_fib.h>
 #include <net/switchdev.h>
 
 /**
+ *	switchdev_trans_item_enqueue - Enqueue data item to transaction queue
+ *
+ *	@trans: transaction
+ *	@data: pointer to data being queued
+ *	@destructor: data destructor
+ *	@tritem: transaction item being queued
+ *
+ *	Enqeueue data item to transaction queue. tritem is typically placed in
+ *	cointainter pointed at by data pointer. Destructor is called on
+ *	transaction abort and after successful commit phase in case
+ *	the caller did not dequeue the item before.
+ */
+void switchdev_trans_item_enqueue(struct switchdev_trans *trans,
+				  void *data, void (*destructor)(void const *),
+				  struct switchdev_trans_item *tritem)
+{
+	tritem->data = data;
+	tritem->destructor = destructor;
+	list_add_tail(&tritem->list, &trans->item_list);
+}
+EXPORT_SYMBOL_GPL(switchdev_trans_item_enqueue);
+
+static struct switchdev_trans_item *
+__switchdev_trans_item_dequeue(struct switchdev_trans *trans)
+{
+	struct switchdev_trans_item *tritem;
+
+	if (list_empty(&trans->item_list))
+		return NULL;
+	tritem = list_first_entry(&trans->item_list,
+				  struct switchdev_trans_item, list);
+	list_del(&tritem->list);
+	return tritem;
+}
+
+/**
+ *	switchdev_trans_item_dequeue - Dequeue data item from transaction queue
+ *
+ *	@trans: transaction
+ */
+void *switchdev_trans_item_dequeue(struct switchdev_trans *trans)
+{
+	struct switchdev_trans_item *tritem;
+
+	tritem = __switchdev_trans_item_dequeue(trans);
+	BUG_ON(!tritem);
+	return tritem->data;
+}
+EXPORT_SYMBOL_GPL(switchdev_trans_item_dequeue);
+
+static void switchdev_trans_init(struct switchdev_trans *trans)
+{
+	INIT_LIST_HEAD(&trans->item_list);
+}
+
+static void switchdev_trans_items_destroy(struct switchdev_trans *trans)
+{
+	struct switchdev_trans_item *tritem;
+
+	while ((tritem = __switchdev_trans_item_dequeue(trans)))
+		tritem->destructor(tritem->data);
+}
+
+static void switchdev_trans_items_warn_destroy(struct net_device *dev,
+					       struct switchdev_trans *trans)
+{
+	WARN(!list_empty(&trans->item_list), "%s: transaction item queue is not empty.\n",
+	     dev->name);
+	switchdev_trans_items_destroy(trans);
+}
+
+/**
  *	switchdev_port_attr_get - Get port attribute
  *
  *	@dev: port device
@@ -62,7 +135,8 @@ int switchdev_port_attr_get(struct net_device *dev, struct switchdev_attr *attr)
 EXPORT_SYMBOL_GPL(switchdev_port_attr_get);
 
 static int __switchdev_port_attr_set(struct net_device *dev,
-				     struct switchdev_attr *attr)
+				     struct switchdev_attr *attr,
+				     struct switchdev_trans *trans)
 {
 	const struct switchdev_ops *ops = dev->switchdev_ops;
 	struct net_device *lower_dev;
@@ -70,7 +144,7 @@ static int __switchdev_port_attr_set(struct net_device *dev,
 	int err = -EOPNOTSUPP;
 
 	if (ops && ops->switchdev_port_attr_set)
-		return ops->switchdev_port_attr_set(dev, attr);
+		return ops->switchdev_port_attr_set(dev, attr, trans);
 
 	if (attr->flags & SWITCHDEV_F_NO_RECURSE)
 		return err;
@@ -81,7 +155,7 @@ static int __switchdev_port_attr_set(struct net_device *dev,
 	 */
 
 	netdev_for_each_lower_dev(dev, lower_dev, iter) {
-		err = __switchdev_port_attr_set(lower_dev, attr);
+		err = __switchdev_port_attr_set(lower_dev, attr, trans);
 		if (err)
 			break;
 	}
@@ -144,6 +218,7 @@ static int switchdev_port_attr_set_defer(struct net_device *dev,
  */
 int switchdev_port_attr_set(struct net_device *dev, struct switchdev_attr *attr)
 {
+	struct switchdev_trans trans;
 	int err;
 
 	if (!rtnl_is_locked()) {
@@ -156,6 +231,8 @@ int switchdev_port_attr_set(struct net_device *dev, struct switchdev_attr *attr)
 		return switchdev_port_attr_set_defer(dev, attr);
 	}
 
+	switchdev_trans_init(&trans);
+
 	/* Phase I: prepare for attr set. Driver/device should fail
 	 * here if there are going to be issues in the commit phase,
 	 * such as lack of resources or support.  The driver/device
@@ -164,7 +241,7 @@ int switchdev_port_attr_set(struct net_device *dev, struct switchdev_attr *attr)
 	 */
 
 	attr->trans_ph = SWITCHDEV_TRANS_PREPARE;
-	err = __switchdev_port_attr_set(dev, attr);
+	err = __switchdev_port_attr_set(dev, attr, &trans);
 	if (err) {
 		/* Prepare phase failed: abort the transaction.  Any
 		 * resources reserved in the prepare phase are
@@ -173,7 +250,8 @@ int switchdev_port_attr_set(struct net_device *dev, struct switchdev_attr *attr)
 
 		if (err != -EOPNOTSUPP) {
 			attr->trans_ph = SWITCHDEV_TRANS_ABORT;
-			__switchdev_port_attr_set(dev, attr);
+			__switchdev_port_attr_set(dev, attr, &trans);
+			switchdev_trans_items_destroy(&trans);
 		}
 
 		return err;
@@ -185,16 +263,18 @@ int switchdev_port_attr_set(struct net_device *dev, struct switchdev_attr *attr)
 	 */
 
 	attr->trans_ph = SWITCHDEV_TRANS_COMMIT;
-	err = __switchdev_port_attr_set(dev, attr);
+	err = __switchdev_port_attr_set(dev, attr, &trans);
 	WARN(err, "%s: Commit of attribute (id=%d) failed.\n",
 	     dev->name, attr->id);
+	switchdev_trans_items_warn_destroy(dev, &trans);
 
 	return err;
 }
 EXPORT_SYMBOL_GPL(switchdev_port_attr_set);
 
 static int __switchdev_port_obj_add(struct net_device *dev,
-				    struct switchdev_obj *obj)
+				    struct switchdev_obj *obj,
+				    struct switchdev_trans *trans)
 {
 	const struct switchdev_ops *ops = dev->switchdev_ops;
 	struct net_device *lower_dev;
@@ -202,7 +282,7 @@ static int __switchdev_port_obj_add(struct net_device *dev,
 	int err = -EOPNOTSUPP;
 
 	if (ops && ops->switchdev_port_obj_add)
-		return ops->switchdev_port_obj_add(dev, obj);
+		return ops->switchdev_port_obj_add(dev, obj, trans);
 
 	/* Switch device port(s) may be stacked under
 	 * bond/team/vlan dev, so recurse down to add object on
@@ -210,7 +290,7 @@ static int __switchdev_port_obj_add(struct net_device *dev,
 	 */
 
 	netdev_for_each_lower_dev(dev, lower_dev, iter) {
-		err = __switchdev_port_obj_add(lower_dev, obj);
+		err = __switchdev_port_obj_add(lower_dev, obj, trans);
 		if (err)
 			break;
 	}
@@ -232,10 +312,13 @@ static int __switchdev_port_obj_add(struct net_device *dev,
  */
 int switchdev_port_obj_add(struct net_device *dev, struct switchdev_obj *obj)
 {
+	struct switchdev_trans trans;
 	int err;
 
 	ASSERT_RTNL();
 
+	switchdev_trans_init(&trans);
+
 	/* Phase I: prepare for obj add. Driver/device should fail
 	 * here if there are going to be issues in the commit phase,
 	 * such as lack of resources or support.  The driver/device
@@ -244,7 +327,7 @@ int switchdev_port_obj_add(struct net_device *dev, struct switchdev_obj *obj)
 	 */
 
 	obj->trans_ph = SWITCHDEV_TRANS_PREPARE;
-	err = __switchdev_port_obj_add(dev, obj);
+	err = __switchdev_port_obj_add(dev, obj, &trans);
 	if (err) {
 		/* Prepare phase failed: abort the transaction.  Any
 		 * resources reserved in the prepare phase are
@@ -253,7 +336,8 @@ int switchdev_port_obj_add(struct net_device *dev, struct switchdev_obj *obj)
 
 		if (err != -EOPNOTSUPP) {
 			obj->trans_ph = SWITCHDEV_TRANS_ABORT;
-			__switchdev_port_obj_add(dev, obj);
+			__switchdev_port_obj_add(dev, obj, &trans);
+			switchdev_trans_items_destroy(&trans);
 		}
 
 		return err;
@@ -265,8 +349,9 @@ int switchdev_port_obj_add(struct net_device *dev, struct switchdev_obj *obj)
 	 */
 
 	obj->trans_ph = SWITCHDEV_TRANS_COMMIT;
-	err = __switchdev_port_obj_add(dev, obj);
+	err = __switchdev_port_obj_add(dev, obj, &trans);
 	WARN(err, "%s: Commit of object (id=%d) failed.\n", dev->name, obj->id);
+	switchdev_trans_items_warn_destroy(dev, &trans);
 
 	return err;
 }