diff options
| -rw-r--r-- | net/Kconfig | 2 | ||||
| -rw-r--r-- | net/core/drop_monitor.c | 46 |
2 files changed, 45 insertions, 3 deletions
diff --git a/net/Kconfig b/net/Kconfig index 4c06c7c513a4..da1282359303 100644 --- a/net/Kconfig +++ b/net/Kconfig @@ -296,7 +296,7 @@ config NET_TCPPROBE module will be called tcp_probe. config NET_DROP_MONITOR - boolean "Network packet drop alerting service" + tristate "Network packet drop alerting service" depends on INET && EXPERIMENTAL && TRACEPOINTS ---help--- This feature provides an alerting service to userspace in the diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c index eca00a96bcf3..3252e7e0a005 100644 --- a/net/core/drop_monitor.c +++ b/net/core/drop_monitor.c @@ -24,6 +24,7 @@ #include <linux/timer.h> #include <linux/bitops.h> #include <linux/slab.h> +#include <linux/module.h> #include <net/genetlink.h> #include <net/netevent.h> @@ -263,9 +264,15 @@ static int set_all_monitor_traces(int state) switch (state) { case TRACE_ON: + if (!try_module_get(THIS_MODULE)) { + rc = -ENODEV; + break; + } + rc |= register_trace_kfree_skb(trace_kfree_skb_hit, NULL); rc |= register_trace_napi_poll(trace_napi_poll_hit, NULL); break; + case TRACE_OFF: rc |= unregister_trace_kfree_skb(trace_kfree_skb_hit, NULL); rc |= unregister_trace_napi_poll(trace_napi_poll_hit, NULL); @@ -281,6 +288,9 @@ static int set_all_monitor_traces(int state) kfree_rcu(new_stat, rcu); } } + + module_put(THIS_MODULE); + break; default: rc = 1; @@ -406,7 +416,7 @@ static int __init init_net_drop_monitor(void) rc = 0; - for_each_present_cpu(cpu) { + for_each_possible_cpu(cpu) { data = &per_cpu(dm_cpu_data, cpu); data->cpu = cpu; INIT_WORK(&data->dm_alert_work, send_dm_alert); @@ -425,4 +435,36 @@ out: return rc; } -late_initcall(init_net_drop_monitor); +static void exit_net_drop_monitor(void) +{ + struct per_cpu_dm_data *data; + int cpu; + + BUG_ON(unregister_netdevice_notifier(&dropmon_net_notifier)); + + /* + * Because of the module_get/put we do in the trace state change path + * we are guarnateed not to have any current users when we get here + * all we need to do is make sure that we don't have any running timers + * or pending schedule calls + */ + + for_each_possible_cpu(cpu) { + data = &per_cpu(dm_cpu_data, cpu); + del_timer_sync(&data->send_timer); + cancel_work_sync(&data->dm_alert_work); + /* + * At this point, we should have exclusive access + * to this struct and can free the skb inside it + */ + kfree_skb(data->skb); + } + + BUG_ON(genl_unregister_family(&net_drop_monitor_family)); +} + +module_init(init_net_drop_monitor); +module_exit(exit_net_drop_monitor); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Neil Horman <nhorman@tuxdriver.com>"); |