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, 9 insertions, 25 deletions

diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 653d64f4a637..0eefb50aae8c 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -326,8 +326,7 @@ dsa_slave_vlan_check_for_8021q_uppers(struct net_device *slave,
 }
 
 static int dsa_slave_vlan_add(struct net_device *dev,
-			      const struct switchdev_obj *obj,
-			      struct switchdev_trans *trans)
+			      const struct switchdev_obj *obj)
 {
 	struct net_device *master = dsa_slave_to_master(dev);
 	struct dsa_port *dp = dsa_slave_to_port(dev);
@@ -345,7 +344,7 @@ static int dsa_slave_vlan_add(struct net_device *dev,
 	/* Deny adding a bridge VLAN when there is already an 802.1Q upper with
 	 * the same VID.
 	 */
-	if (trans->ph_prepare && br_vlan_enabled(dp->bridge_dev)) {
+	if (br_vlan_enabled(dp->bridge_dev)) {
 		rcu_read_lock();
 		err = dsa_slave_vlan_check_for_8021q_uppers(dev, &vlan);
 		rcu_read_unlock();
@@ -353,7 +352,7 @@ static int dsa_slave_vlan_add(struct net_device *dev,
 			return err;
 	}
 
-	err = dsa_port_vlan_add(dp, &vlan, trans);
+	err = dsa_port_vlan_add(dp, &vlan);
 	if (err)
 		return err;
 
@@ -363,7 +362,7 @@ static int dsa_slave_vlan_add(struct net_device *dev,
 	 */
 	vlan.flags &= ~BRIDGE_VLAN_INFO_PVID;
 
-	err = dsa_port_vlan_add(dp->cpu_dp, &vlan, trans);
+	err = dsa_port_vlan_add(dp->cpu_dp, &vlan);
 	if (err)
 		return err;
 
@@ -372,7 +371,6 @@ static int dsa_slave_vlan_add(struct net_device *dev,
 
 static int dsa_slave_port_obj_add(struct net_device *dev,
 				  const struct switchdev_obj *obj,
-				  struct switchdev_trans *trans,
 				  struct netlink_ext_ack *extack)
 {
 	struct dsa_port *dp = dsa_slave_to_port(dev);
@@ -387,17 +385,16 @@ static int dsa_slave_port_obj_add(struct net_device *dev,
 	case SWITCHDEV_OBJ_ID_PORT_MDB:
 		if (obj->orig_dev != dev)
 			return -EOPNOTSUPP;
-		err = dsa_port_mdb_add(dp, SWITCHDEV_OBJ_PORT_MDB(obj), trans);
+		err = dsa_port_mdb_add(dp, SWITCHDEV_OBJ_PORT_MDB(obj));
 		break;
 	case SWITCHDEV_OBJ_ID_HOST_MDB:
 		/* DSA can directly translate this to a normal MDB add,
 		 * but on the CPU port.
 		 */
-		err = dsa_port_mdb_add(dp->cpu_dp, SWITCHDEV_OBJ_PORT_MDB(obj),
-				       trans);
+		err = dsa_port_mdb_add(dp->cpu_dp, SWITCHDEV_OBJ_PORT_MDB(obj));
 		break;
 	case SWITCHDEV_OBJ_ID_PORT_VLAN:
-		err = dsa_slave_vlan_add(dev, obj, trans);
+		err = dsa_slave_vlan_add(dev, obj);
 		break;
 	default:
 		err = -EOPNOTSUPP;
@@ -1286,28 +1283,15 @@ static int dsa_slave_vlan_rx_add_vid(struct net_device *dev, __be16 proto,
 		/* This API only allows programming tagged, non-PVID VIDs */
 		.flags = 0,
 	};
-	struct switchdev_trans trans;
 	int ret;
 
 	/* User port... */
-	trans.ph_prepare = true;
-	ret = dsa_port_vlan_add(dp, &vlan, &trans);
-	if (ret)
-		return ret;
-
-	trans.ph_prepare = false;
-	ret = dsa_port_vlan_add(dp, &vlan, &trans);
+	ret = dsa_port_vlan_add(dp, &vlan);
 	if (ret)
 		return ret;
 
 	/* And CPU port... */
-	trans.ph_prepare = true;
-	ret = dsa_port_vlan_add(dp->cpu_dp, &vlan, &trans);
-	if (ret)
-		return ret;
-
-	trans.ph_prepare = false;
-	ret = dsa_port_vlan_add(dp->cpu_dp, &vlan, &trans);
+	ret = dsa_port_vlan_add(dp->cpu_dp, &vlan);
 	if (ret)
 		return ret;