Merge tag 'for-3.5' of git://openrisc.net/jonas/linux

[karo-tx-linux.git] / net / core / drop_monitor.c

diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c
index a7cad741df012a2b7790246d6c2d569bac38bda4..3252e7e0a0055ad07fa1c02979500650703f6820 100644 (file)
--- a/net/core/drop_monitor.c
+++ b/net/core/drop_monitor.c
@@ -4,6 +4,8 @@
  * Copyright (C) 2009 Neil Horman <nhorman@tuxdriver.com>
  */
 
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
 #include <linux/string.h>
@@ -22,6 +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>
 
@@ -261,9 +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);
@@ -279,6 +288,9 @@ static int set_all_monitor_traces(int state)
                                kfree_rcu(new_stat, rcu);
                        }
                }
+
+               module_put(THIS_MODULE);
+
                break;
        default:
                rc = 1;
@@ -381,10 +393,10 @@ static int __init init_net_drop_monitor(void)
        struct per_cpu_dm_data *data;
        int cpu, rc;
 
-       printk(KERN_INFO "Initializing network drop monitor service\n");
+       pr_info("Initializing network drop monitor service\n");
 
        if (sizeof(void *) > 8) {
-               printk(KERN_ERR "Unable to store program counters on this arch, Drop monitor failed\n");
+               pr_err("Unable to store program counters on this arch, Drop monitor failed\n");
                return -ENOSPC;
        }
 
@@ -392,19 +404,19 @@ static int __init init_net_drop_monitor(void)
                                           dropmon_ops,
                                           ARRAY_SIZE(dropmon_ops));
        if (rc) {
-               printk(KERN_ERR "Could not create drop monitor netlink family\n");
+               pr_err("Could not create drop monitor netlink family\n");
                return rc;
        }
 
        rc = register_netdevice_notifier(&dropmon_net_notifier);
        if (rc < 0) {
-               printk(KERN_CRIT "Failed to register netdevice notifier\n");
+               pr_crit("Failed to register netdevice notifier\n");
                goto out_unreg;
        }
 
        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);
@@ -423,4 +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>");