net: switchdev: remove the transaction structure from port object notifiers

Since the introduction of the switchdev API, port objects were
transmitted to drivers for offloading using a two-step transactional
model, with a prepare phase that was supposed to catch all errors, and a
commit phase that was supposed to never fail.

Some classes of failures can never be avoided, like hardware access, or
memory allocation. In the latter case, merely attempting to move the
memory allocation to the preparation phase makes it impossible to avoid
memory leaks, since commit 91cf8eceffc1 ("switchdev: Remove unused
transaction item queue") which has removed the unused mechanism of
passing on the allocated memory between one phase and another.

It is time we admit that separating the preparation from the commit
phase is something that is best left for the driver to decide, and not
something that should be baked into the API, especially since there are
no switchdev callers that depend on this.

This patch removes the struct switchdev_trans member from switchdev port
object notifier structures, and converts drivers to not look at this
member.

Where driver conversion is trivial (like in the case of the Marvell
Prestera driver, NXP DPAA2 switch, TI CPSW, and Rocker drivers), it is
done in this patch.

Where driver conversion needs more attention (DSA, Mellanox Spectrum),
the conversion is left for subsequent patches and here we only fake the
prepare/commit phases at a lower level, just not in the switchdev
notifier itself.

Where the code has a natural structure that is best left alone as a
preparation and a commit phase (as in the case of the Ocelot switch),
that structure is left in place, just made to not depend upon the
switchdev transactional model.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

6 files changed, 77 insertions, 98 deletions

diff --git a/drivers/net/ethernet/marvell/prestera/prestera_switchdev.c b/drivers/net/ethernet/marvell/prestera/prestera_switchdev.c
index c87667c1cca0..3235458a5501 100644
--- a/drivers/net/ethernet/marvell/prestera/prestera_switchdev.c
+++ b/drivers/net/ethernet/marvell/prestera/prestera_switchdev.c
@@ -1020,7 +1020,6 @@ prestera_bridge_port_vlan_del(struct prestera_port *port,
 
 static int prestera_port_vlans_add(struct prestera_port *port,
 				   const struct switchdev_obj_port_vlan *vlan,
-				   struct switchdev_trans *trans,
 				   struct netlink_ext_ack *extack)
 {
 	bool flag_untagged = vlan->flags & BRIDGE_VLAN_INFO_UNTAGGED;
@@ -1034,9 +1033,6 @@ static int prestera_port_vlans_add(struct prestera_port *port,
 	if (netif_is_bridge_master(dev))
 		return 0;
 
-	if (switchdev_trans_ph_commit(trans))
-		return 0;
-
 	br_port = prestera_bridge_port_by_dev(sw->swdev, dev);
 	if (WARN_ON(!br_port))
 		return -EINVAL;
@@ -1052,7 +1048,6 @@ static int prestera_port_vlans_add(struct prestera_port *port,
 
 static int prestera_port_obj_add(struct net_device *dev,
 				 const struct switchdev_obj *obj,
-				 struct switchdev_trans *trans,
 				 struct netlink_ext_ack *extack)
 {
 	struct prestera_port *port = netdev_priv(dev);
@@ -1061,7 +1056,7 @@ static int prestera_port_obj_add(struct net_device *dev,
 	switch (obj->id) {
 	case SWITCHDEV_OBJ_ID_PORT_VLAN:
 		vlan = SWITCHDEV_OBJ_PORT_VLAN(obj);
-		return prestera_port_vlans_add(port, vlan, trans, extack);
+		return prestera_port_vlans_add(port, vlan, extack);
 	default:
 		return -EOPNOTSUPP;
 	}
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c
index 7039cff69680..eff5920aed06 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c
@@ -1704,8 +1704,7 @@ static int mlxsw_sp_port_remove_from_mid(struct mlxsw_sp_port *mlxsw_sp_port,
 }
 
 static int mlxsw_sp_port_mdb_add(struct mlxsw_sp_port *mlxsw_sp_port,
-				 const struct switchdev_obj_port_mdb *mdb,
-				 struct switchdev_trans *trans)
+				 const struct switchdev_obj_port_mdb *mdb)
 {
 	struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
 	struct net_device *orig_dev = mdb->obj.orig_dev;
@@ -1717,9 +1716,6 @@ static int mlxsw_sp_port_mdb_add(struct mlxsw_sp_port *mlxsw_sp_port,
 	u16 fid_index;
 	int err = 0;
 
-	if (switchdev_trans_ph_commit(trans))
-		return 0;
-
 	bridge_port = mlxsw_sp_bridge_port_find(mlxsw_sp->bridge, orig_dev);
 	if (!bridge_port)
 		return 0;
@@ -1801,32 +1797,38 @@ mlxsw_sp_port_mrouter_update_mdb(struct mlxsw_sp_port *mlxsw_sp_port,
 
 static int mlxsw_sp_port_obj_add(struct net_device *dev,
 				 const struct switchdev_obj *obj,
-				 struct switchdev_trans *trans,
 				 struct netlink_ext_ack *extack)
 {
 	struct mlxsw_sp_port *mlxsw_sp_port = netdev_priv(dev);
 	const struct switchdev_obj_port_vlan *vlan;
+	struct switchdev_trans trans;
 	int err = 0;
 
 	switch (obj->id) {
 	case SWITCHDEV_OBJ_ID_PORT_VLAN:
 		vlan = SWITCHDEV_OBJ_PORT_VLAN(obj);
-		err = mlxsw_sp_port_vlans_add(mlxsw_sp_port, vlan, trans,
+
+		trans.ph_prepare = true;
+		err = mlxsw_sp_port_vlans_add(mlxsw_sp_port, vlan, &trans,
 					      extack);
 
-		if (switchdev_trans_ph_prepare(trans)) {
-			/* The event is emitted before the changes are actually
-			 * applied to the bridge. Therefore schedule the respin
-			 * call for later, so that the respin logic sees the
-			 * updated bridge state.
-			 */
-			mlxsw_sp_span_respin(mlxsw_sp_port->mlxsw_sp);
-		}
+		/* The event is emitted before the changes are actually
+		 * applied to the bridge. Therefore schedule the respin
+		 * call for later, so that the respin logic sees the
+		 * updated bridge state.
+		 */
+		mlxsw_sp_span_respin(mlxsw_sp_port->mlxsw_sp);
+
+		if (err)
+			break;
+
+		trans.ph_prepare = false;
+		err = mlxsw_sp_port_vlans_add(mlxsw_sp_port, vlan, &trans,
+					      extack);
 		break;
 	case SWITCHDEV_OBJ_ID_PORT_MDB:
 		err = mlxsw_sp_port_mdb_add(mlxsw_sp_port,
-					    SWITCHDEV_OBJ_PORT_MDB(obj),
-					    trans);
+					    SWITCHDEV_OBJ_PORT_MDB(obj));
 		break;
 	default:
 		err = -EOPNOTSUPP;
@@ -3386,13 +3388,13 @@ out:
 static int
 mlxsw_sp_switchdev_vxlan_vlans_add(struct net_device *vxlan_dev,
 				   struct switchdev_notifier_port_obj_info *
-				   port_obj_info)
+				   port_obj_info,
+				   struct switchdev_trans *trans)
 {
 	struct switchdev_obj_port_vlan *vlan =
 		SWITCHDEV_OBJ_PORT_VLAN(port_obj_info->obj);
 	bool flag_untagged = vlan->flags & BRIDGE_VLAN_INFO_UNTAGGED;
 	bool flag_pvid = vlan->flags & BRIDGE_VLAN_INFO_PVID;
-	struct switchdev_trans *trans = port_obj_info->trans;
 	struct mlxsw_sp_bridge_device *bridge_device;
 	struct netlink_ext_ack *extack;
 	struct mlxsw_sp *mlxsw_sp;
@@ -3462,12 +3464,22 @@ mlxsw_sp_switchdev_handle_vxlan_obj_add(struct net_device *vxlan_dev,
 					struct switchdev_notifier_port_obj_info *
 					port_obj_info)
 {
+	struct switchdev_trans trans;
 	int err = 0;
 
 	switch (port_obj_info->obj->id) {
 	case SWITCHDEV_OBJ_ID_PORT_VLAN:
+		trans.ph_prepare = true;
+		err = mlxsw_sp_switchdev_vxlan_vlans_add(vxlan_dev,
+							 port_obj_info,
+							 &trans);
+		if (err)
+			break;
+
+		trans.ph_prepare = false;
 		err = mlxsw_sp_switchdev_vxlan_vlans_add(vxlan_dev,
-							 port_obj_info);
+							 port_obj_info,
+							 &trans);
 		break;
 	default:
 		break;
diff --git a/drivers/net/ethernet/mscc/ocelot_net.c b/drivers/net/ethernet/mscc/ocelot_net.c
index 3b8718b143bb..16d958a6e206 100644
--- a/drivers/net/ethernet/mscc/ocelot_net.c
+++ b/drivers/net/ethernet/mscc/ocelot_net.c
@@ -890,33 +890,27 @@ static int ocelot_port_attr_set(struct net_device *dev,
 }
 
 static int ocelot_port_obj_add_vlan(struct net_device *dev,
-				    const struct switchdev_obj_port_vlan *vlan,
-				    struct switchdev_trans *trans)
+				    const struct switchdev_obj_port_vlan *vlan)
 {
 	bool untagged = vlan->flags & BRIDGE_VLAN_INFO_UNTAGGED;
 	bool pvid = vlan->flags & BRIDGE_VLAN_INFO_PVID;
 	int ret;
 
-	if (switchdev_trans_ph_prepare(trans))
-		ret = ocelot_vlan_vid_prepare(dev, vlan->vid, pvid, untagged);
-	else
-		ret = ocelot_vlan_vid_add(dev, vlan->vid, pvid, untagged);
+	ret = ocelot_vlan_vid_prepare(dev, vlan->vid, pvid, untagged);
+	if (ret)
+		return ret;
 
-	return ret;
+	return ocelot_vlan_vid_add(dev, vlan->vid, pvid, untagged);
 }
 
 static int ocelot_port_obj_add_mdb(struct net_device *dev,
-				   const struct switchdev_obj_port_mdb *mdb,
-				   struct switchdev_trans *trans)
+				   const struct switchdev_obj_port_mdb *mdb)
 {
 	struct ocelot_port_private *priv = netdev_priv(dev);
 	struct ocelot_port *ocelot_port = &priv->port;
 	struct ocelot *ocelot = ocelot_port->ocelot;
 	int port = priv->chip_port;
 
-	if (switchdev_trans_ph_prepare(trans))
-		return 0;
-
 	return ocelot_port_mdb_add(ocelot, port, mdb);
 }
 
@@ -933,7 +927,6 @@ static int ocelot_port_obj_del_mdb(struct net_device *dev,
 
 static int ocelot_port_obj_add(struct net_device *dev,
 			       const struct switchdev_obj *obj,
-			       struct switchdev_trans *trans,
 			       struct netlink_ext_ack *extack)
 {
 	int ret = 0;
@@ -941,12 +934,10 @@ static int ocelot_port_obj_add(struct net_device *dev,
 	switch (obj->id) {
 	case SWITCHDEV_OBJ_ID_PORT_VLAN:
 		ret = ocelot_port_obj_add_vlan(dev,
-					       SWITCHDEV_OBJ_PORT_VLAN(obj),
-					       trans);
+					       SWITCHDEV_OBJ_PORT_VLAN(obj));
 		break;
 	case SWITCHDEV_OBJ_ID_PORT_MDB:
-		ret = ocelot_port_obj_add_mdb(dev, SWITCHDEV_OBJ_PORT_MDB(obj),
-					      trans);
+		ret = ocelot_port_obj_add_mdb(dev, SWITCHDEV_OBJ_PORT_MDB(obj));
 		break;
 	default:
 		return -EOPNOTSUPP;
diff --git a/drivers/net/ethernet/rocker/rocker_main.c b/drivers/net/ethernet/rocker/rocker_main.c
index dd0bc7f0aaee..1018d3759316 100644
--- a/drivers/net/ethernet/rocker/rocker_main.c
+++ b/drivers/net/ethernet/rocker/rocker_main.c
@@ -1638,17 +1638,13 @@ rocker_world_port_attr_bridge_ageing_time_set(struct rocker_port *rocker_port,
 
 static int
 rocker_world_port_obj_vlan_add(struct rocker_port *rocker_port,
-			       const struct switchdev_obj_port_vlan *vlan,
-			       struct switchdev_trans *trans)
+			       const struct switchdev_obj_port_vlan *vlan)
 {
 	struct rocker_world_ops *wops = rocker_port->rocker->wops;
 
 	if (!wops->port_obj_vlan_add)
 		return -EOPNOTSUPP;
 
-	if (switchdev_trans_ph_prepare(trans))
-		return 0;
-
 	return wops->port_obj_vlan_add(rocker_port, vlan);
 }
 
@@ -2102,8 +2098,7 @@ static int rocker_port_attr_set(struct net_device *dev,
 }
 
 static int rocker_port_obj_add(struct net_device *dev,
-			       const struct switchdev_obj *obj,
-			       struct switchdev_trans *trans)
+			       const struct switchdev_obj *obj)
 {
 	struct rocker_port *rocker_port = netdev_priv(dev);
 	int err = 0;
@@ -2111,8 +2106,7 @@ static int rocker_port_obj_add(struct net_device *dev,
 	switch (obj->id) {
 	case SWITCHDEV_OBJ_ID_PORT_VLAN:
 		err = rocker_world_port_obj_vlan_add(rocker_port,
-						     SWITCHDEV_OBJ_PORT_VLAN(obj),
-						     trans);
+						     SWITCHDEV_OBJ_PORT_VLAN(obj));
 		break;
 	default:
 		err = -EOPNOTSUPP;
@@ -2847,8 +2841,7 @@ rocker_switchdev_port_obj_event(unsigned long event, struct net_device *netdev,
 
 	switch (event) {
 	case SWITCHDEV_PORT_OBJ_ADD:
-		err = rocker_port_obj_add(netdev, port_obj_info->obj,
-					  port_obj_info->trans);
+		err = rocker_port_obj_add(netdev, port_obj_info->obj);
 		break;
 	case SWITCHDEV_PORT_OBJ_DEL:
 		err = rocker_port_obj_del(netdev, port_obj_info->obj);
diff --git a/drivers/net/ethernet/ti/cpsw_switchdev.c b/drivers/net/ethernet/ti/cpsw_switchdev.c
index 8a36228acc5d..3232f483c068 100644
--- a/drivers/net/ethernet/ti/cpsw_switchdev.c
+++ b/drivers/net/ethernet/ti/cpsw_switchdev.c
@@ -253,8 +253,7 @@ static int cpsw_port_vlan_del(struct cpsw_priv *priv, u16 vid,
 }
 
 static int cpsw_port_vlans_add(struct cpsw_priv *priv,
-			       const struct switchdev_obj_port_vlan *vlan,
-			       struct switchdev_trans *trans)
+			       const struct switchdev_obj_port_vlan *vlan)
 {
 	bool untag = vlan->flags & BRIDGE_VLAN_INFO_UNTAGGED;
 	struct net_device *orig_dev = vlan->obj.orig_dev;
@@ -267,15 +266,11 @@ static int cpsw_port_vlans_add(struct cpsw_priv *priv,
 	if (cpu_port && !(vlan->flags & BRIDGE_VLAN_INFO_BRENTRY))
 		return 0;
 
-	if (switchdev_trans_ph_prepare(trans))
-		return 0;
-
 	return cpsw_port_vlan_add(priv, untag, pvid, vlan->vid, orig_dev);
 }
 
 static int cpsw_port_mdb_add(struct cpsw_priv *priv,
-			     struct switchdev_obj_port_mdb *mdb,
-			     struct switchdev_trans *trans)
+			     struct switchdev_obj_port_mdb *mdb)
 
 {
 	struct net_device *orig_dev = mdb->obj.orig_dev;
@@ -284,9 +279,6 @@ static int cpsw_port_mdb_add(struct cpsw_priv *priv,
 	int port_mask;
 	int err;
 
-	if (switchdev_trans_ph_prepare(trans))
-		return 0;
-
 	if (cpu_port)
 		port_mask = BIT(HOST_PORT_NUM);
 	else
@@ -325,7 +317,6 @@ static int cpsw_port_mdb_del(struct cpsw_priv *priv,
 
 static int cpsw_port_obj_add(struct net_device *ndev,
 			     const struct switchdev_obj *obj,
-			     struct switchdev_trans *trans,
 			     struct netlink_ext_ack *extack)
 {
 	struct switchdev_obj_port_vlan *vlan = SWITCHDEV_OBJ_PORT_VLAN(obj);
@@ -338,11 +329,11 @@ static int cpsw_port_obj_add(struct net_device *ndev,
 
 	switch (obj->id) {
 	case SWITCHDEV_OBJ_ID_PORT_VLAN:
-		err = cpsw_port_vlans_add(priv, vlan, trans);
+		err = cpsw_port_vlans_add(priv, vlan);
 		break;
 	case SWITCHDEV_OBJ_ID_PORT_MDB:
 	case SWITCHDEV_OBJ_ID_HOST_MDB:
-		err = cpsw_port_mdb_add(priv, mdb, trans);
+		err = cpsw_port_mdb_add(priv, mdb);
 		break;
 	default:
 		err = -EOPNOTSUPP;
diff --git a/drivers/staging/fsl-dpaa2/ethsw/ethsw.c b/drivers/staging/fsl-dpaa2/ethsw/ethsw.c
index 62edb8d01f4e..197dea9c3b42 100644
--- a/drivers/staging/fsl-dpaa2/ethsw/ethsw.c
+++ b/drivers/staging/fsl-dpaa2/ethsw/ethsw.c
@@ -975,33 +975,38 @@ static int dpaa2_switch_port_attr_set(struct net_device *netdev,
 }
 
 static int dpaa2_switch_port_vlans_add(struct net_device *netdev,
-				       const struct switchdev_obj_port_vlan *vlan,
-				       struct switchdev_trans *trans)
+				       const struct switchdev_obj_port_vlan *vlan)
 {
 	struct ethsw_port_priv *port_priv = netdev_priv(netdev);
 	struct ethsw_core *ethsw = port_priv->ethsw_data;
 	struct dpsw_attr *attr = &ethsw->sw_attr;
 	int err = 0;
 
-	if (switchdev_trans_ph_prepare(trans)) {
-		/* Make sure that the VLAN is not already configured
-		 * on the switch port
-		 */
-		if (port_priv->vlans[vlan->vid] & ETHSW_VLAN_MEMBER)
-			return -EEXIST;
+	/* Make sure that the VLAN is not already configured
+	 * on the switch port
+	 */
+	if (port_priv->vlans[vlan->vid] & ETHSW_VLAN_MEMBER)
+		return -EEXIST;
 
-		/* Check if there is space for a new VLAN */
-		err = dpsw_get_attributes(ethsw->mc_io, 0, ethsw->dpsw_handle,
-					  &ethsw->sw_attr);
-		if (err) {
-			netdev_err(netdev, "dpsw_get_attributes err %d\n", err);
-			return err;
-		}
-		if (attr->max_vlans - attr->num_vlans < 1)
-			return -ENOSPC;
+	/* Check if there is space for a new VLAN */
+	err = dpsw_get_attributes(ethsw->mc_io, 0, ethsw->dpsw_handle,
+				  &ethsw->sw_attr);
+	if (err) {
+		netdev_err(netdev, "dpsw_get_attributes err %d\n", err);
+		return err;
+	}
+	if (attr->max_vlans - attr->num_vlans < 1)
+		return -ENOSPC;
 
-		return 0;
+	/* Check if there is space for a new VLAN */
+	err = dpsw_get_attributes(ethsw->mc_io, 0, ethsw->dpsw_handle,
+				  &ethsw->sw_attr);
+	if (err) {
+		netdev_err(netdev, "dpsw_get_attributes err %d\n", err);
+		return err;
 	}
+	if (attr->max_vlans - attr->num_vlans < 1)
+		return -ENOSPC;
 
 	if (!port_priv->ethsw_data->vlans[vlan->vid]) {
 		/* this is a new VLAN */
@@ -1033,15 +1038,11 @@ static int dpaa2_switch_port_lookup_address(struct net_device *netdev, int is_uc
 }
 
 static int dpaa2_switch_port_mdb_add(struct net_device *netdev,
-				     const struct switchdev_obj_port_mdb *mdb,
-				     struct switchdev_trans *trans)
+				     const struct switchdev_obj_port_mdb *mdb)
 {
 	struct ethsw_port_priv *port_priv = netdev_priv(netdev);
 	int err;
 
-	if (switchdev_trans_ph_prepare(trans))
-		return 0;
-
 	/* Check if address is already set on this port */
 	if (dpaa2_switch_port_lookup_address(netdev, 0, mdb->addr))
 		return -EEXIST;
@@ -1060,21 +1061,18 @@ static int dpaa2_switch_port_mdb_add(struct net_device *netdev,
 }
 
 static int dpaa2_switch_port_obj_add(struct net_device *netdev,
-				     const struct switchdev_obj *obj,
-				     struct switchdev_trans *trans)
+				     const struct switchdev_obj *obj)
 {
 	int err;
 
 	switch (obj->id) {
 	case SWITCHDEV_OBJ_ID_PORT_VLAN:
 		err = dpaa2_switch_port_vlans_add(netdev,
-						  SWITCHDEV_OBJ_PORT_VLAN(obj),
-						  trans);
+						  SWITCHDEV_OBJ_PORT_VLAN(obj));
 		break;
 	case SWITCHDEV_OBJ_ID_PORT_MDB:
 		err = dpaa2_switch_port_mdb_add(netdev,
-						SWITCHDEV_OBJ_PORT_MDB(obj),
-						trans);
+						SWITCHDEV_OBJ_PORT_MDB(obj));
 		break;
 	default:
 		err = -EOPNOTSUPP;
@@ -1394,8 +1392,7 @@ static int dpaa2_switch_port_obj_event(unsigned long event,
 
 	switch (event) {
 	case SWITCHDEV_PORT_OBJ_ADD:
-		err = dpaa2_switch_port_obj_add(netdev, port_obj_info->obj,
-						port_obj_info->trans);
+		err = dpaa2_switch_port_obj_add(netdev, port_obj_info->obj);
 		break;
 	case SWITCHDEV_PORT_OBJ_DEL:
 		err = dpaa2_switch_port_obj_del(netdev, port_obj_info->obj);