drop_monitor: Add extack support

Add various extack messages to make drop_monitor more user friendly.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c
index 9080e62245b9c3f50a9e969c96bac4b46a30cf48..1d463c0d4bc51340852652e195c5f8d17726ff04 100644 (file)
--- a/net/core/drop_monitor.c
+++ b/net/core/drop_monitor.c
@@ -241,7 +241,7 @@ static void trace_napi_poll_hit(void *ignore, struct napi_struct *napi,
        rcu_read_unlock();
 }
 
-static int set_all_monitor_traces(int state)
+static int set_all_monitor_traces(int state, struct netlink_ext_ack *extack)
 {
        int rc = 0;
        struct dm_hw_stat_delta *new_stat = NULL;
@@ -250,6 +250,7 @@ static int set_all_monitor_traces(int state)
        mutex_lock(&net_dm_mutex);
 
        if (state == trace_state) {
+               NL_SET_ERR_MSG_MOD(extack, "Trace state already set to requested state");
                rc = -EAGAIN;
                goto out_unlock;
        }
@@ -257,6 +258,7 @@ static int set_all_monitor_traces(int state)
        switch (state) {
        case TRACE_ON:
                if (!try_module_get(THIS_MODULE)) {
+                       NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module");
                        rc = -ENODEV;
                        break;
                }
@@ -303,6 +305,8 @@ static int set_all_monitor_traces(int state)
 static int net_dm_cmd_config(struct sk_buff *skb,
                        struct genl_info *info)
 {
+       NL_SET_ERR_MSG_MOD(info->extack, "Command not supported");
+
        return -EOPNOTSUPP;
 }
 
@@ -311,9 +315,9 @@ static int net_dm_cmd_trace(struct sk_buff *skb,
 {
        switch (info->genlhdr->cmd) {
        case NET_DM_CMD_START:
-               return set_all_monitor_traces(TRACE_ON);
+               return set_all_monitor_traces(TRACE_ON, info->extack);
        case NET_DM_CMD_STOP:
-               return set_all_monitor_traces(TRACE_OFF);
+               return set_all_monitor_traces(TRACE_OFF, info->extack);
        }
 
        return -EOPNOTSUPP;