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-rw-r--r--net/Kconfig2
-rw-r--r--net/core/drop_monitor.c46
2 files changed, 45 insertions, 3 deletions
diff --git a/net/Kconfig b/net/Kconfig
index 4c06c7c513a..da128235930 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 eca00a96bcf..3252e7e0a00 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>");