net: switchdev: remove the transaction structure from port attributes

Since the introduction of the switchdev API, port attributes 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
attribute notifier structures, and converts drivers to not look at this
member.

In part, this patch contains a revert of my previous commit 2e554a7a5d8a
("net: dsa: propagate switchdev vlan_filtering prepare phase to
drivers").

For the most part, the conversion was trivial except for:
- Rocker's world implementation based on Broadcom OF-DPA had an odd
  implementation of ofdpa_port_attr_bridge_flags_set. The conversion was
  done mechanically, by pasting the implementation twice, then only
  keeping the code that would get executed during prepare phase on top,
  then only keeping the code that gets executed during the commit phase
  on bottom, then simplifying the resulting code until this was obtained.
- DSA's offloading of STP state, bridge flags, VLAN filtering and
  multicast router could be converted right away. But the ageing time
  could not, so a shim was introduced and this was left for a further
  commit.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de> # hellcreek
Reviewed-by: Linus Walleij <linus.walleij@linaro.org> # RTL8366RB
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 13 insertions, 50 deletions

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c
index eff5920aed06..409c206f813f 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c
@@ -527,7 +527,6 @@ mlxsw_sp_port_bridge_vlan_stp_set(struct mlxsw_sp_port *mlxsw_sp_port,
 }
 
 static int mlxsw_sp_port_attr_stp_state_set(struct mlxsw_sp_port *mlxsw_sp_port,
-					    struct switchdev_trans *trans,
 					    struct net_device *orig_dev,
 					    u8 state)
 {
@@ -535,9 +534,6 @@ static int mlxsw_sp_port_attr_stp_state_set(struct mlxsw_sp_port *mlxsw_sp_port,
 	struct mlxsw_sp_bridge_vlan *bridge_vlan;
 	int err;
 
-	if (switchdev_trans_ph_prepare(trans))
-		return 0;
-
 	/* It's possible we failed to enslave the port, yet this
 	 * operation is executed due to it being deferred.
 	 */
@@ -659,7 +655,6 @@ err_port_bridge_vlan_learning_set:
 
 static int mlxsw_sp_port_attr_br_pre_flags_set(struct mlxsw_sp_port
 					       *mlxsw_sp_port,
-					       struct switchdev_trans *trans,
 					       unsigned long brport_flags)
 {
 	if (brport_flags & ~(BR_LEARNING | BR_FLOOD | BR_MCAST_FLOOD))
@@ -669,16 +664,12 @@ static int mlxsw_sp_port_attr_br_pre_flags_set(struct mlxsw_sp_port
 }
 
 static int mlxsw_sp_port_attr_br_flags_set(struct mlxsw_sp_port *mlxsw_sp_port,
-					   struct switchdev_trans *trans,
 					   struct net_device *orig_dev,
 					   unsigned long brport_flags)
 {
 	struct mlxsw_sp_bridge_port *bridge_port;
 	int err;
 
-	if (switchdev_trans_ph_prepare(trans))
-		return 0;
-
 	bridge_port = mlxsw_sp_bridge_port_find(mlxsw_sp_port->mlxsw_sp->bridge,
 						orig_dev);
 	if (!bridge_port)
@@ -724,35 +715,26 @@ static int mlxsw_sp_ageing_set(struct mlxsw_sp *mlxsw_sp, u32 ageing_time)
 }
 
 static int mlxsw_sp_port_attr_br_ageing_set(struct mlxsw_sp_port *mlxsw_sp_port,
-					    struct switchdev_trans *trans,
 					    unsigned long ageing_clock_t)
 {
 	struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
 	unsigned long ageing_jiffies = clock_t_to_jiffies(ageing_clock_t);
 	u32 ageing_time = jiffies_to_msecs(ageing_jiffies) / 1000;
 
-	if (switchdev_trans_ph_prepare(trans)) {
-		if (ageing_time < MLXSW_SP_MIN_AGEING_TIME ||
-		    ageing_time > MLXSW_SP_MAX_AGEING_TIME)
-			return -ERANGE;
-		else
-			return 0;
-	}
+	if (ageing_time < MLXSW_SP_MIN_AGEING_TIME ||
+	    ageing_time > MLXSW_SP_MAX_AGEING_TIME)
+		return -ERANGE;
 
 	return mlxsw_sp_ageing_set(mlxsw_sp, ageing_time);
 }
 
 static int mlxsw_sp_port_attr_br_vlan_set(struct mlxsw_sp_port *mlxsw_sp_port,
-					  struct switchdev_trans *trans,
 					  struct net_device *orig_dev,
 					  bool vlan_enabled)
 {
 	struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
 	struct mlxsw_sp_bridge_device *bridge_device;
 
-	if (!switchdev_trans_ph_prepare(trans))
-		return 0;
-
 	bridge_device = mlxsw_sp_bridge_device_find(mlxsw_sp->bridge, orig_dev);
 	if (WARN_ON(!bridge_device))
 		return -EINVAL;
@@ -765,16 +747,12 @@ static int mlxsw_sp_port_attr_br_vlan_set(struct mlxsw_sp_port *mlxsw_sp_port,
 }
 
 static int mlxsw_sp_port_attr_br_vlan_proto_set(struct mlxsw_sp_port *mlxsw_sp_port,
-						struct switchdev_trans *trans,
 						struct net_device *orig_dev,
 						u16 vlan_proto)
 {
 	struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
 	struct mlxsw_sp_bridge_device *bridge_device;
 
-	if (!switchdev_trans_ph_prepare(trans))
-		return 0;
-
 	bridge_device = mlxsw_sp_bridge_device_find(mlxsw_sp->bridge, orig_dev);
 	if (WARN_ON(!bridge_device))
 		return -EINVAL;
@@ -784,16 +762,12 @@ static int mlxsw_sp_port_attr_br_vlan_proto_set(struct mlxsw_sp_port *mlxsw_sp_p
 }
 
 static int mlxsw_sp_port_attr_mrouter_set(struct mlxsw_sp_port *mlxsw_sp_port,
-					  struct switchdev_trans *trans,
 					  struct net_device *orig_dev,
 					  bool is_port_mrouter)
 {
 	struct mlxsw_sp_bridge_port *bridge_port;
 	int err;
 
-	if (switchdev_trans_ph_prepare(trans))
-		return 0;
-
 	bridge_port = mlxsw_sp_bridge_port_find(mlxsw_sp_port->mlxsw_sp->bridge,
 						orig_dev);
 	if (!bridge_port)
@@ -825,7 +799,6 @@ static bool mlxsw_sp_mc_flood(const struct mlxsw_sp_bridge_port *bridge_port)
 }
 
 static int mlxsw_sp_port_mc_disabled_set(struct mlxsw_sp_port *mlxsw_sp_port,
-					 struct switchdev_trans *trans,
 					 struct net_device *orig_dev,
 					 bool mc_disabled)
 {
@@ -834,9 +807,6 @@ static int mlxsw_sp_port_mc_disabled_set(struct mlxsw_sp_port *mlxsw_sp_port,
 	struct mlxsw_sp_bridge_port *bridge_port;
 	int err;
 
-	if (switchdev_trans_ph_prepare(trans))
-		return 0;
-
 	/* It's possible we failed to enslave the port, yet this
 	 * operation is executed due to it being deferred.
 	 */
@@ -896,16 +866,12 @@ mlxsw_sp_bridge_mrouter_update_mdb(struct mlxsw_sp *mlxsw_sp,
 
 static int
 mlxsw_sp_port_attr_br_mrouter_set(struct mlxsw_sp_port *mlxsw_sp_port,
-				  struct switchdev_trans *trans,
 				  struct net_device *orig_dev,
 				  bool is_mrouter)
 {
 	struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
 	struct mlxsw_sp_bridge_device *bridge_device;
 
-	if (switchdev_trans_ph_prepare(trans))
-		return 0;
-
 	/* It's possible we failed to enslave the port, yet this
 	 * operation is executed due to it being deferred.
 	 */
@@ -921,54 +887,52 @@ mlxsw_sp_port_attr_br_mrouter_set(struct mlxsw_sp_port *mlxsw_sp_port,
 }
 
 static int mlxsw_sp_port_attr_set(struct net_device *dev,
-				  const struct switchdev_attr *attr,
-				  struct switchdev_trans *trans)
+				  const struct switchdev_attr *attr)
 {
 	struct mlxsw_sp_port *mlxsw_sp_port = netdev_priv(dev);
 	int err;
 
 	switch (attr->id) {
 	case SWITCHDEV_ATTR_ID_PORT_STP_STATE:
-		err = mlxsw_sp_port_attr_stp_state_set(mlxsw_sp_port, trans,
+		err = mlxsw_sp_port_attr_stp_state_set(mlxsw_sp_port,
 						       attr->orig_dev,
 						       attr->u.stp_state);
 		break;
 	case SWITCHDEV_ATTR_ID_PORT_PRE_BRIDGE_FLAGS:
 		err = mlxsw_sp_port_attr_br_pre_flags_set(mlxsw_sp_port,
-							  trans,
 							  attr->u.brport_flags);
 		break;
 	case SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS:
-		err = mlxsw_sp_port_attr_br_flags_set(mlxsw_sp_port, trans,
+		err = mlxsw_sp_port_attr_br_flags_set(mlxsw_sp_port,
 						      attr->orig_dev,
 						      attr->u.brport_flags);
 		break;
 	case SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME:
-		err = mlxsw_sp_port_attr_br_ageing_set(mlxsw_sp_port, trans,
+		err = mlxsw_sp_port_attr_br_ageing_set(mlxsw_sp_port,
 						       attr->u.ageing_time);
 		break;
 	case SWITCHDEV_ATTR_ID_BRIDGE_VLAN_FILTERING:
-		err = mlxsw_sp_port_attr_br_vlan_set(mlxsw_sp_port, trans,
+		err = mlxsw_sp_port_attr_br_vlan_set(mlxsw_sp_port,
 						     attr->orig_dev,
 						     attr->u.vlan_filtering);
 		break;
 	case SWITCHDEV_ATTR_ID_BRIDGE_VLAN_PROTOCOL:
-		err = mlxsw_sp_port_attr_br_vlan_proto_set(mlxsw_sp_port, trans,
+		err = mlxsw_sp_port_attr_br_vlan_proto_set(mlxsw_sp_port,
 							   attr->orig_dev,
 							   attr->u.vlan_protocol);
 		break;
 	case SWITCHDEV_ATTR_ID_PORT_MROUTER:
-		err = mlxsw_sp_port_attr_mrouter_set(mlxsw_sp_port, trans,
+		err = mlxsw_sp_port_attr_mrouter_set(mlxsw_sp_port,
 						     attr->orig_dev,
 						     attr->u.mrouter);
 		break;
 	case SWITCHDEV_ATTR_ID_BRIDGE_MC_DISABLED:
-		err = mlxsw_sp_port_mc_disabled_set(mlxsw_sp_port, trans,
+		err = mlxsw_sp_port_mc_disabled_set(mlxsw_sp_port,
 						    attr->orig_dev,
 						    attr->u.mc_disabled);
 		break;
 	case SWITCHDEV_ATTR_ID_BRIDGE_MROUTER:
-		err = mlxsw_sp_port_attr_br_mrouter_set(mlxsw_sp_port, trans,
+		err = mlxsw_sp_port_attr_br_mrouter_set(mlxsw_sp_port,
 							attr->orig_dev,
 							attr->u.mrouter);
 		break;
@@ -977,8 +941,7 @@ static int mlxsw_sp_port_attr_set(struct net_device *dev,
 		break;
 	}
 
-	if (switchdev_trans_ph_commit(trans))
-		mlxsw_sp_span_respin(mlxsw_sp_port->mlxsw_sp);
+	mlxsw_sp_span_respin(mlxsw_sp_port->mlxsw_sp);
 
 	return err;
 }