net/mlx5e: Add trace point for neigh used value update

Allow tracing result of neigh used value update task that is executed
periodically on workqueue.

Usage example:
 ># cd /sys/kernel/debug/tracing
 ># echo mlx5:mlx5e_tc_update_neigh_used_value >> set_event
 ># cat trace
    ...
    kworker/u48:4-8806  [009] ...1 55117.882428: mlx5e_tc_update_neigh_used_value:
netdev: ens1f0 IPv4: 1.1.1.10 IPv6: ::ffff:1.1.1.10 neigh_used=1

Added corresponding documentation in
    Documentation/networking/device-driver/mellanox/mlx5.rst
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Reviewed-by: Dmytro Linkin <dmitrolin@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

Documentation/networking/device_drivers/mellanox/mlx5.rst

@@ -251,3 +251,10 @@ tc and eswitch offloads tracepoints:
     $ cat /sys/kernel/debug/tracing/trace
     ...
     tc-6546  [010] ...1  2679.704889: mlx5e_stats_flower: cookie=0000000060eb3d6a bytes=0 packets=0 lastused=4295560217
+
+- mlx5e_tc_update_neigh_used_value: trace tunnel rule neigh update value offloaded to mlx5::
+
+    $ echo mlx5:mlx5e_tc_update_neigh_used_value >> /sys/kernel/debug/tracing/set_event
+    $ cat /sys/kernel/debug/tracing/trace
+    ...
+    kworker/u48:4-8806  [009] ...1 55117.882428: mlx5e_tc_update_neigh_used_value: netdev: ens1f0 IPv4: 1.1.1.10 IPv6: ::ffff:1.1.1.10 neigh_used=1

drivers/net/ethernet/mellanox/mlx5/core/diag/en_tc_tracepoint.h

@@ -10,6 +10,7 @@
 #include <linux/tracepoint.h>
 #include <linux/trace_seq.h>
 #include <net/flow_offload.h>
+#include "en_rep.h"
 
 #define __parse_action(ids, num) parse_action(p, ids, num)
 
@@ -73,6 +74,36 @@ TRACE_EVENT(mlx5e_stats_flower,
 		      )
 );
 
+TRACE_EVENT(mlx5e_tc_update_neigh_used_value,
+	    TP_PROTO(const struct mlx5e_neigh_hash_entry *nhe, bool neigh_used),
+	    TP_ARGS(nhe, neigh_used),
+	    TP_STRUCT__entry(__string(devname, nhe->m_neigh.dev->name)
+			     __array(u8, v4, 4)
+			     __array(u8, v6, 16)
+			     __field(bool, neigh_used)
+			     ),
+	    TP_fast_assign(const struct mlx5e_neigh *mn = &nhe->m_neigh;
+			struct in6_addr *pin6;
+			__be32 *p32;
+
+			__assign_str(devname, mn->dev->name);
+			__entry->neigh_used = neigh_used;
+
+			p32 = (__be32 *)__entry->v4;
+			pin6 = (struct in6_addr *)__entry->v6;
+			if (mn->family == AF_INET) {
+				*p32 = mn->dst_ip.v4;
+				ipv6_addr_set_v4mapped(*p32, pin6);
+			} else if (mn->family == AF_INET6) {
+				*pin6 = mn->dst_ip.v6;
+			}
+			),
+	    TP_printk("netdev: %s IPv4: %pI4 IPv6: %pI6c neigh_used=%d\n",
+		      __get_str(devname), __entry->v4, __entry->v6,
+		      __entry->neigh_used
+		      )
+);
+
 #endif /* _MLX5_TC_TP_ */
 
 /* This part must be outside protection */

drivers/net/ethernet/mellanox/mlx5/core/en_tc.c

@@ -1536,6 +1536,8 @@ void mlx5e_tc_update_neigh_used_value(struct mlx5e_neigh_hash_entry *nhe)
 		}
 	}
 
+	trace_mlx5e_tc_update_neigh_used_value(nhe, neigh_used);
+
 	if (neigh_used) {
 		nhe->reported_lastuse = jiffies;