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Diffstat (limited to 'net/core/drop_monitor.c')
-rw-r--r--net/core/drop_monitor.c89
1 files changed, 65 insertions, 24 deletions
diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c
index 7f36b38e060f..a7cad741df01 100644
--- a/net/core/drop_monitor.c
+++ b/net/core/drop_monitor.c
@@ -42,13 +42,14 @@ static void send_dm_alert(struct work_struct *unused);
* 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;
+ struct sk_buff __rcu *skb;
atomic_t dm_hit_count;
struct timer_list send_timer;
+ int cpu;
};
struct dm_hw_stat_delta {
@@ -79,29 +80,53 @@ static void 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;
+ struct sk_buff *oskb = rcu_dereference_protected(data->skb, 1);
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));
- msg = nla_data(nla);
- memset(msg, 0, al);
- atomic_set(&data->dm_hit_count, dm_hit_limit);
+ skb = genlmsg_new(al, GFP_KERNEL);
+
+ if (skb) {
+ genlmsg_put(skb, 0, 0, &net_drop_monitor_family,
+ 0, NET_DM_CMD_ALERT);
+ nla = nla_reserve(skb, NLA_UNSPEC,
+ sizeof(struct net_dm_alert_msg));
+ msg = nla_data(nla);
+ memset(msg, 0, al);
+ } else
+ schedule_work_on(data->cpu, &data->dm_alert_work);
+
+ /*
+ * Don't need to lock this, since we are guaranteed to only
+ * run this on a single cpu at a time.
+ * Note also that we only update data->skb if the old and new skb
+ * pointers don't match. This ensures that we don't continually call
+ * synchornize_rcu if we repeatedly fail to alloc a new netlink message.
+ */
+ if (skb != oskb) {
+ rcu_assign_pointer(data->skb, skb);
+
+ synchronize_rcu();
+
+ atomic_set(&data->dm_hit_count, dm_hit_limit);
+ }
+
}
static void send_dm_alert(struct work_struct *unused)
{
struct sk_buff *skb;
- struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data);
+ struct per_cpu_dm_data *data = &get_cpu_var(dm_cpu_data);
+
+ WARN_ON_ONCE(data->cpu != smp_processor_id());
/*
* Grab the skb we're about to send
*/
- skb = data->skb;
+ skb = rcu_dereference_protected(data->skb, 1);
/*
* Replace it with a new one
@@ -111,8 +136,10 @@ static void send_dm_alert(struct work_struct *unused)
/*
* Ship it!
*/
- genlmsg_multicast(skb, 0, NET_DM_GRP_ALERT, GFP_KERNEL);
+ if (skb)
+ genlmsg_multicast(skb, 0, NET_DM_GRP_ALERT, GFP_KERNEL);
+ put_cpu_var(dm_cpu_data);
}
/*
@@ -123,9 +150,11 @@ static void send_dm_alert(struct work_struct *unused)
*/
static void sched_send_work(unsigned long unused)
{
- struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data);
+ struct per_cpu_dm_data *data = &get_cpu_var(dm_cpu_data);
+
+ schedule_work_on(smp_processor_id(), &data->dm_alert_work);
- schedule_work(&data->dm_alert_work);
+ put_cpu_var(dm_cpu_data);
}
static void trace_drop_common(struct sk_buff *skb, void *location)
@@ -134,8 +163,15 @@ 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 = &get_cpu_var(dm_cpu_data);
+
+
+ rcu_read_lock();
+ dskb = rcu_dereference(data->skb);
+ if (!dskb)
+ goto out;
if (!atomic_add_unless(&data->dm_hit_count, -1, 0)) {
/*
@@ -144,12 +180,13 @@ static void trace_drop_common(struct sk_buff *skb, void *location)
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++) {
if (!memcmp(&location, msg->points[i].pc, sizeof(void *))) {
msg->points[i].count++;
+ atomic_inc(&data->dm_hit_count);
goto out;
}
}
@@ -157,7 +194,7 @@ static void trace_drop_common(struct sk_buff *skb, void *location)
/*
* 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;
@@ -169,6 +206,8 @@ static void trace_drop_common(struct sk_buff *skb, void *location)
}
out:
+ rcu_read_unlock();
+ put_cpu_var(dm_cpu_data);
return;
}
@@ -213,7 +252,7 @@ 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 +291,7 @@ 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 +334,12 @@ 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 +350,7 @@ static int dropmon_net_event(struct notifier_block *ev_block,
}
}
}
- spin_unlock(&trace_state_lock);
+ mutex_unlock(&trace_state_mutex);
break;
}
out:
@@ -367,13 +406,15 @@ 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);
+ data->cpu = cpu;
INIT_WORK(&data->dm_alert_work, send_dm_alert);
init_timer(&data->send_timer);
data->send_timer.data = cpu;
data->send_timer.function = sched_send_work;
+ reset_per_cpu_data(data);
}
+
goto out;
out_unreg:
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-12 12:02:19 +0000