drop_monitor: Filter control packets in drop monitor

Previously, devlink called into drop monitor in order to report hardware
originated drops / exceptions. devlink intentionally filtered control
packets and did not pass them to drop monitor as they were not dropped
by the underlying hardware.

Now drop monitor registers its probe on a generic 'devlink_trap_report'
tracepoint and should therefore perform this filtering itself instead of
having devlink do that.

Add the trap type as metadata and have drop monitor ignore control
packets.

Signed-off-by: Ido Schimmel <[email protected]>
Reviewed-by: Jiri Pirko <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Author: idosch

include/net/devlink.h

@@ -630,12 +630,14 @@ struct devlink_health_reporter_ops {
  * @trap_group_name: Trap group name.
  * @input_dev: Input netdevice.
  * @fa_cookie: Flow action user cookie.
+ * @trap_type: Trap type.
  */
 struct devlink_trap_metadata {
 	const char *trap_name;
 	const char *trap_group_name;
 	struct net_device *input_dev;
 	const struct flow_action_cookie *fa_cookie;
+	enum devlink_trap_type trap_type;
 };
 
 /**

net/core/devlink.c

@@ -9269,6 +9269,7 @@ devlink_trap_report_metadata_set(struct devlink_trap_metadata *metadata,
 	metadata->trap_name = trap_item->trap->name;
 	metadata->trap_group_name = trap_item->group_item->group->name;
 	metadata->fa_cookie = fa_cookie;
+	metadata->trap_type = trap_item->trap->type;
 
 	spin_lock(&in_devlink_port->type_lock);
 	if (in_devlink_port->type == DEVLINK_PORT_TYPE_ETH)
@@ -9294,13 +9295,6 @@ void devlink_trap_report(struct devlink *devlink, struct sk_buff *skb,
 	devlink_trap_stats_update(trap_item->stats, skb->len);
 	devlink_trap_stats_update(trap_item->group_item->stats, skb->len);
 
-	/* Control packets were not dropped by the device or encountered an
-	 * exception during forwarding and therefore should not be reported to
-	 * the kernel's drop monitor.
-	 */
-	if (trap_item->trap->type == DEVLINK_TRAP_TYPE_CONTROL)
-		return;
-
 	if (trace_devlink_trap_report_enabled()) {
 		struct devlink_trap_metadata metadata = {};
 

net/core/drop_monitor.c

@@ -444,6 +444,9 @@ net_dm_hw_trap_summary_probe(void *ignore, const struct devlink *devlink,
 	unsigned long flags;
 	int i;
 
+	if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL)
+		return;
+
 	hw_data = this_cpu_ptr(&dm_hw_cpu_data);
 	spin_lock_irqsave(&hw_data->lock, flags);
 	hw_entries = hw_data->hw_entries;
@@ -937,6 +940,9 @@ net_dm_hw_trap_packet_probe(void *ignore, const struct devlink *devlink,
 	struct sk_buff *nskb;
 	unsigned long flags;
 
+	if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL)
+		return;
+
 	if (!skb_mac_header_was_set(skb))
 		return;