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>

1 files changed, 28 insertions, 31 deletions

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);