drop_monitor: consider inserted data in genlmsg_end
[pandora-kernel.git] / net / core / drop_monitor.c
index 7f36b38..32b2fa4 100644 (file)
 #define TRACE_ON 1
 #define TRACE_OFF 0
 
-static void send_dm_alert(struct work_struct *unused);
-
-
 /*
  * Globals, our netlink socket pointer
  * and the work handle that will send up
  * netlink alerts
  */
 static int trace_state = TRACE_OFF;
-static DEFINE_SPINLOCK(trace_state_lock);
+static DEFINE_MUTEX(trace_state_mutex);
 
 struct per_cpu_dm_data {
-       struct work_struct dm_alert_work;
-       struct sk_buff *skb;
-       atomic_t dm_hit_count;
-       struct timer_list send_timer;
+       spinlock_t              lock;
+       struct sk_buff          *skb;
+       struct work_struct      dm_alert_work;
+       struct timer_list       send_timer;
 };
 
 struct dm_hw_stat_delta {
@@ -64,7 +61,6 @@ static struct genl_family net_drop_monitor_family = {
        .hdrsize        = 0,
        .name           = "NET_DM",
        .version        = 2,
-       .maxattr        = NET_DM_CMD_MAX,
 };
 
 static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data);
@@ -74,56 +70,80 @@ static int dm_delay = 1;
 static unsigned long dm_hw_check_delta = 2*HZ;
 static LIST_HEAD(hw_stats_list);
 
-static void reset_per_cpu_data(struct per_cpu_dm_data *data)
+static struct sk_buff *reset_per_cpu_data(struct per_cpu_dm_data *data)
 {
        size_t al;
        struct net_dm_alert_msg *msg;
        struct nlattr *nla;
+       struct sk_buff *skb;
+       unsigned long flags;
+       void *msg_header;
 
        al = sizeof(struct net_dm_alert_msg);
        al += dm_hit_limit * sizeof(struct net_dm_drop_point);
        al += sizeof(struct nlattr);
 
-       data->skb = genlmsg_new(al, GFP_KERNEL);
-       genlmsg_put(data->skb, 0, 0, &net_drop_monitor_family,
-                       0, NET_DM_CMD_ALERT);
-       nla = nla_reserve(data->skb, NLA_UNSPEC, sizeof(struct net_dm_alert_msg));
+       skb = genlmsg_new(al, GFP_KERNEL);
+
+       if (!skb)
+               goto err;
+
+       msg_header = genlmsg_put(skb, 0, 0, &net_drop_monitor_family,
+                                0, NET_DM_CMD_ALERT);
+       if (!msg_header) {
+               nlmsg_free(skb);
+               skb = NULL;
+               goto err;
+       }
+       nla = nla_reserve(skb, NLA_UNSPEC,
+                         sizeof(struct net_dm_alert_msg));
+       if (!nla) {
+               nlmsg_free(skb);
+               skb = NULL;
+               goto err;
+       }
        msg = nla_data(nla);
        memset(msg, 0, al);
-       atomic_set(&data->dm_hit_count, dm_hit_limit);
+       goto out;
+
+err:
+       mod_timer(&data->send_timer, jiffies + HZ / 10);
+out:
+       spin_lock_irqsave(&data->lock, flags);
+       swap(data->skb, skb);
+       spin_unlock_irqrestore(&data->lock, flags);
+
+       if (skb) {
+               struct nlmsghdr *nlh = (struct nlmsghdr *)skb->data;
+               struct genlmsghdr *gnlh = (struct genlmsghdr *)nlmsg_data(nlh);
+
+               genlmsg_end(skb, genlmsg_data(gnlh));
+       }
+
+       return skb;
 }
 
-static void send_dm_alert(struct work_struct *unused)
+static void send_dm_alert(struct work_struct *work)
 {
        struct sk_buff *skb;
-       struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data);
-
-       /*
-        * Grab the skb we're about to send
-        */
-       skb = data->skb;
+       struct per_cpu_dm_data *data;
 
-       /*
-        * Replace it with a new one
-        */
-       reset_per_cpu_data(data);
+       data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
 
-       /*
-        * Ship it!
-        */
-       genlmsg_multicast(skb, 0, NET_DM_GRP_ALERT, GFP_KERNEL);
+       skb = reset_per_cpu_data(data);
 
+       if (skb)
+               genlmsg_multicast(skb, 0, NET_DM_GRP_ALERT, GFP_KERNEL);
 }
 
 /*
  * This is the timer function to delay the sending of an alert
  * in the event that more drops will arrive during the
- * hysteresis period.  Note that it operates under the timer interrupt
- * so we don't need to disable preemption here
+ * hysteresis period.
  */
-static void sched_send_work(unsigned long unused)
+static void sched_send_work(unsigned long _data)
 {
-       struct per_cpu_dm_data *data =  &__get_cpu_var(dm_cpu_data);
+       struct per_cpu_dm_data *data = (struct per_cpu_dm_data *)_data;
 
        schedule_work(&data->dm_alert_work);
 }
@@ -134,17 +154,19 @@ static void trace_drop_common(struct sk_buff *skb, void *location)
        struct nlmsghdr *nlh;
        struct nlattr *nla;
        int i;
-       struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data);
+       struct sk_buff *dskb;
+       struct per_cpu_dm_data *data;
+       unsigned long flags;
 
+       local_irq_save(flags);
+       data = &__get_cpu_var(dm_cpu_data);
+       spin_lock(&data->lock);
+       dskb = data->skb;
 
-       if (!atomic_add_unless(&data->dm_hit_count, -1, 0)) {
-               /*
-                * we're already at zero, discard this hit
-                */
+       if (!dskb)
                goto out;
-       }
 
-       nlh = (struct nlmsghdr *)data->skb->data;
+       nlh = (struct nlmsghdr *)dskb->data;
        nla = genlmsg_data(nlmsg_data(nlh));
        msg = nla_data(nla);
        for (i = 0; i < msg->entries; i++) {
@@ -153,11 +175,12 @@ static void trace_drop_common(struct sk_buff *skb, void *location)
                        goto out;
                }
        }
-
+       if (msg->entries == dm_hit_limit)
+               goto out;
        /*
         * We need to create a new entry
         */
-       __nla_reserve_nohdr(data->skb, sizeof(struct net_dm_drop_point));
+       __nla_reserve_nohdr(dskb, sizeof(struct net_dm_drop_point));
        nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point));
        memcpy(msg->points[msg->entries].pc, &location, sizeof(void *));
        msg->points[msg->entries].count = 1;
@@ -165,11 +188,11 @@ static void trace_drop_common(struct sk_buff *skb, void *location)
 
        if (!timer_pending(&data->send_timer)) {
                data->send_timer.expires = jiffies + dm_delay * HZ;
-               add_timer_on(&data->send_timer, smp_processor_id());
+               add_timer(&data->send_timer);
        }
 
 out:
-       return;
+       spin_unlock_irqrestore(&data->lock, flags);
 }
 
 static void trace_kfree_skb_hit(void *ignore, struct sk_buff *skb, void *location)
@@ -213,7 +236,7 @@ static int set_all_monitor_traces(int state)
        struct dm_hw_stat_delta *new_stat = NULL;
        struct dm_hw_stat_delta *temp;
 
-       spin_lock(&trace_state_lock);
+       mutex_lock(&trace_state_mutex);
 
        if (state == trace_state) {
                rc = -EAGAIN;
@@ -252,7 +275,7 @@ static int set_all_monitor_traces(int state)
                rc = -EINPROGRESS;
 
 out_unlock:
-       spin_unlock(&trace_state_lock);
+       mutex_unlock(&trace_state_mutex);
 
        return rc;
 }
@@ -295,12 +318,12 @@ static int dropmon_net_event(struct notifier_block *ev_block,
 
                new_stat->dev = dev;
                new_stat->last_rx = jiffies;
-               spin_lock(&trace_state_lock);
+               mutex_lock(&trace_state_mutex);
                list_add_rcu(&new_stat->list, &hw_stats_list);
-               spin_unlock(&trace_state_lock);
+               mutex_unlock(&trace_state_mutex);
                break;
        case NETDEV_UNREGISTER:
-               spin_lock(&trace_state_lock);
+               mutex_lock(&trace_state_mutex);
                list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) {
                        if (new_stat->dev == dev) {
                                new_stat->dev = NULL;
@@ -311,7 +334,7 @@ static int dropmon_net_event(struct notifier_block *ev_block,
                                }
                        }
                }
-               spin_unlock(&trace_state_lock);
+               mutex_unlock(&trace_state_mutex);
                break;
        }
 out:
@@ -367,13 +390,15 @@ static int __init init_net_drop_monitor(void)
 
        for_each_present_cpu(cpu) {
                data = &per_cpu(dm_cpu_data, cpu);
-               reset_per_cpu_data(data);
                INIT_WORK(&data->dm_alert_work, send_dm_alert);
                init_timer(&data->send_timer);
-               data->send_timer.data = cpu;
+               data->send_timer.data = (unsigned long)data;
                data->send_timer.function = sched_send_work;
+               spin_lock_init(&data->lock);
+               reset_per_cpu_data(data);
        }
 
+
        goto out;
 
 out_unreg: