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>

3 files changed, 22 insertions, 53 deletions

diff --git a/drivers/net/ethernet/rocker/rocker.h b/drivers/net/ethernet/rocker/rocker.h
index 6fad25321dc5..315a6e5c0f59 100644
--- a/drivers/net/ethernet/rocker/rocker.h
+++ b/drivers/net/ethernet/rocker/rocker.h
@@ -103,15 +103,13 @@ struct rocker_world_ops {
 	int (*port_attr_stp_state_set)(struct rocker_port *rocker_port,
 				       u8 state);
 	int (*port_attr_bridge_flags_set)(struct rocker_port *rocker_port,
-					  unsigned long brport_flags,
-					  struct switchdev_trans *trans);
+					  unsigned long brport_flags);
 	int (*port_attr_bridge_flags_support_get)(const struct rocker_port *
 						  rocker_port,
 						  unsigned long *
 						  p_brport_flags);
 	int (*port_attr_bridge_ageing_time_set)(struct rocker_port *rocker_port,
-						u32 ageing_time,
-						struct switchdev_trans *trans);
+						u32 ageing_time);
 	int (*port_obj_vlan_add)(struct rocker_port *rocker_port,
 				 const struct switchdev_obj_port_vlan *vlan);
 	int (*port_obj_vlan_del)(struct rocker_port *rocker_port,
diff --git a/drivers/net/ethernet/rocker/rocker_main.c b/drivers/net/ethernet/rocker/rocker_main.c
index 1018d3759316..740a715c49c6 100644
--- a/drivers/net/ethernet/rocker/rocker_main.c
+++ b/drivers/net/ethernet/rocker/rocker_main.c
@@ -1550,17 +1550,13 @@ static void rocker_world_port_stop(struct rocker_port *rocker_port)
 }
 
 static int rocker_world_port_attr_stp_state_set(struct rocker_port *rocker_port,
-						u8 state,
-						struct switchdev_trans *trans)
+						u8 state)
 {
 	struct rocker_world_ops *wops = rocker_port->rocker->wops;
 
 	if (!wops->port_attr_stp_state_set)
 		return -EOPNOTSUPP;
 
-	if (switchdev_trans_ph_prepare(trans))
-		return 0;
-
 	return wops->port_attr_stp_state_set(rocker_port, state);
 }
 
@@ -1580,8 +1576,7 @@ rocker_world_port_attr_bridge_flags_support_get(const struct rocker_port *
 
 static int
 rocker_world_port_attr_pre_bridge_flags_set(struct rocker_port *rocker_port,
-					    unsigned long brport_flags,
-					    struct switchdev_trans *trans)
+					    unsigned long brport_flags)
 {
 	struct rocker_world_ops *wops = rocker_port->rocker->wops;
 	unsigned long brport_flags_s;
@@ -1603,37 +1598,26 @@ rocker_world_port_attr_pre_bridge_flags_set(struct rocker_port *rocker_port,
 
 static int
 rocker_world_port_attr_bridge_flags_set(struct rocker_port *rocker_port,
-					unsigned long brport_flags,
-					struct switchdev_trans *trans)
+					unsigned long brport_flags)
 {
 	struct rocker_world_ops *wops = rocker_port->rocker->wops;
 
 	if (!wops->port_attr_bridge_flags_set)
 		return -EOPNOTSUPP;
 
-	if (switchdev_trans_ph_prepare(trans))
-		return 0;
-
-	return wops->port_attr_bridge_flags_set(rocker_port, brport_flags,
-						trans);
+	return wops->port_attr_bridge_flags_set(rocker_port, brport_flags);
 }
 
 static int
 rocker_world_port_attr_bridge_ageing_time_set(struct rocker_port *rocker_port,
-					      u32 ageing_time,
-					      struct switchdev_trans *trans)
-
+					      u32 ageing_time)
 {
 	struct rocker_world_ops *wops = rocker_port->rocker->wops;
 
 	if (!wops->port_attr_bridge_ageing_time_set)
 		return -EOPNOTSUPP;
 
-	if (switchdev_trans_ph_prepare(trans))
-		return 0;
-
-	return wops->port_attr_bridge_ageing_time_set(rocker_port, ageing_time,
-						      trans);
+	return wops->port_attr_bridge_ageing_time_set(rocker_port, ageing_time);
 }
 
 static int
@@ -2062,8 +2046,7 @@ static const struct net_device_ops rocker_port_netdev_ops = {
  ********************/
 
 static int rocker_port_attr_set(struct net_device *dev,
-				const struct switchdev_attr *attr,
-				struct switchdev_trans *trans)
+				const struct switchdev_attr *attr)
 {
 	struct rocker_port *rocker_port = netdev_priv(dev);
 	int err = 0;
@@ -2071,23 +2054,19 @@ static int rocker_port_attr_set(struct net_device *dev,
 	switch (attr->id) {
 	case SWITCHDEV_ATTR_ID_PORT_STP_STATE:
 		err = rocker_world_port_attr_stp_state_set(rocker_port,
-							   attr->u.stp_state,
-							   trans);
+							   attr->u.stp_state);
 		break;
 	case SWITCHDEV_ATTR_ID_PORT_PRE_BRIDGE_FLAGS:
 		err = rocker_world_port_attr_pre_bridge_flags_set(rocker_port,
-							      attr->u.brport_flags,
-							      trans);
+							      attr->u.brport_flags);
 		break;
 	case SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS:
 		err = rocker_world_port_attr_bridge_flags_set(rocker_port,
-							      attr->u.brport_flags,
-							      trans);
+							      attr->u.brport_flags);
 		break;
 	case SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME:
 		err = rocker_world_port_attr_bridge_ageing_time_set(rocker_port,
-								    attr->u.ageing_time,
-								    trans);
+								    attr->u.ageing_time);
 		break;
 	default:
 		err = -EOPNOTSUPP;
@@ -2719,8 +2698,7 @@ rocker_switchdev_port_attr_set_event(struct net_device *netdev,
 {
 	int err;
 
-	err = rocker_port_attr_set(netdev, port_attr_info->attr,
-				   port_attr_info->trans);
+	err = rocker_port_attr_set(netdev, port_attr_info->attr);
 
 	port_attr_info->handled = true;
 	return notifier_from_errno(err);
diff --git a/drivers/net/ethernet/rocker/rocker_ofdpa.c b/drivers/net/ethernet/rocker/rocker_ofdpa.c
index d9d5188b7627..d067da1ef070 100644
--- a/drivers/net/ethernet/rocker/rocker_ofdpa.c
+++ b/drivers/net/ethernet/rocker/rocker_ofdpa.c
@@ -2488,8 +2488,7 @@ static int ofdpa_port_attr_stp_state_set(struct rocker_port *rocker_port,
 }
 
 static int ofdpa_port_attr_bridge_flags_set(struct rocker_port *rocker_port,
-					    unsigned long brport_flags,
-					    struct switchdev_trans *trans)
+					    unsigned long brport_flags)
 {
 	struct ofdpa_port *ofdpa_port = rocker_port->wpriv;
 	unsigned long orig_flags;
@@ -2497,14 +2496,11 @@ static int ofdpa_port_attr_bridge_flags_set(struct rocker_port *rocker_port,
 
 	orig_flags = ofdpa_port->brport_flags;
 	ofdpa_port->brport_flags = brport_flags;
-	if ((orig_flags ^ ofdpa_port->brport_flags) & BR_LEARNING &&
-	    !switchdev_trans_ph_prepare(trans))
+
+	if ((orig_flags ^ ofdpa_port->brport_flags) & BR_LEARNING)
 		err = rocker_port_set_learning(ofdpa_port->rocker_port,
 					       !!(ofdpa_port->brport_flags & BR_LEARNING));
 
-	if (switchdev_trans_ph_prepare(trans))
-		ofdpa_port->brport_flags = orig_flags;
-
 	return err;
 }
 
@@ -2520,18 +2516,15 @@ ofdpa_port_attr_bridge_flags_support_get(const struct rocker_port *
 
 static int
 ofdpa_port_attr_bridge_ageing_time_set(struct rocker_port *rocker_port,
-				       u32 ageing_time,
-				       struct switchdev_trans *trans)
+				       u32 ageing_time)
 {
 	struct ofdpa_port *ofdpa_port = rocker_port->wpriv;
 	struct ofdpa *ofdpa = ofdpa_port->ofdpa;
 
-	if (!switchdev_trans_ph_prepare(trans)) {
-		ofdpa_port->ageing_time = clock_t_to_jiffies(ageing_time);
-		if (ofdpa_port->ageing_time < ofdpa->ageing_time)
-			ofdpa->ageing_time = ofdpa_port->ageing_time;
-		mod_timer(&ofdpa_port->ofdpa->fdb_cleanup_timer, jiffies);
-	}
+	ofdpa_port->ageing_time = clock_t_to_jiffies(ageing_time);
+	if (ofdpa_port->ageing_time < ofdpa->ageing_time)
+		ofdpa->ageing_time = ofdpa_port->ageing_time;
+	mod_timer(&ofdpa_port->ofdpa->fdb_cleanup_timer, jiffies);
 
 	return 0;
 }