From: martin Zhang <zhangjunweimar...@didichuxing.com>
Every net ns has its own trace_state,
and use a ref to control trace state of whole kernel.
trace_state in struct per_ns_dm_cb:
Just like the previous trace state, record the trace state for
every net ns. Possible values are ON/OFF.
dm_trace_ref: record how many net namespace is set to
TRACE_ON. increase when a net ns change to ON,
and decrease for OFF.
Signed-off-by: martin Zhang <zhangjunweimar...@didichuxing.com>
---
net/core/drop_monitor.c | 88 +++++++++++++++++++++++++++++++++++++++++--------
1 file changed, 75 insertions(+), 13 deletions(-)
diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c
index 6a75e04..0cf25c3 100644
--- a/net/core/drop_monitor.c
+++ b/net/core/drop_monitor.c
@@ -49,10 +49,16 @@
struct ns_pcpu_dm_data {
};
+/**
+ * struct per_ns_dm_cb - drop monitor control block in per net ns.
+ * @trace_state: the trace state.
+ * @ns_dm_mutex: protect whole per_ns_dm_cb.
+ */
struct per_ns_dm_cb {
+ int trace_state;
+ struct mutex ns_dm_mutex;
};
-static int trace_state = TRACE_OFF;
static DEFINE_MUTEX(trace_state_mutex);
struct per_cpu_dm_data {
@@ -70,6 +76,7 @@ struct dm_hw_stat_delta {
unsigned long last_drop_val;
};
+int dm_trace_ref;
static int dm_net_id __read_mostly;
static struct genl_family net_drop_monitor_family;
@@ -254,9 +261,16 @@ static int set_all_monitor_traces(int state)
mutex_lock(&trace_state_mutex);
- if (state == trace_state) {
- rc = -EAGAIN;
- goto out_unlock;
+ //Cases: Only inc/dec reference value.
+ if (state == TRACE_ON && dm_trace_ref > 0)
+ goto skip_register_trace;
+ else if (state == TRACE_OFF && dm_trace_ref > 1)
+ goto skip_register_trace;
+
+ //Bad cases.
+ if (dm_trace_ref < 0 || (dm_trace_ref == 0 && state == TRACE_OFF)) {
+ rc = -EINPROGRESS;
+ goto skip_register_trace;
}
switch (state) {
@@ -294,12 +308,15 @@ static int set_all_monitor_traces(int state)
break;
}
- if (!rc)
- trace_state = state;
- else
+skip_register_trace:
+ if (!rc) {
+ if (state == TRACE_ON)
+ dm_trace_ref++;
+ else if (state == TRACE_OFF)
+ dm_trace_ref--;
+ } else
rc = -EINPROGRESS;
-out_unlock:
mutex_unlock(&trace_state_mutex);
return rc;
@@ -315,22 +332,65 @@ static int net_dm_cmd_config(struct sk_buff *skb,
static int net_dm_cmd_trace(struct sk_buff *skb,
struct genl_info *info)
{
+ int state;
+ struct net *net;
+ struct per_ns_dm_cb *ns_dm_cb;
+
+ if (!skb->sk)
+ return -ENOTSUPP;
+ net = sock_net(skb->sk);
+ ns_dm_cb = net_generic(net, dm_net_id);
+
+ if (!ns_dm_cb)
+ return -ENOMEM;
+
switch (info->genlhdr->cmd) {
case NET_DM_CMD_START:
- return set_all_monitor_traces(TRACE_ON);
+ state = TRACE_ON;
+ break;
+
case NET_DM_CMD_STOP:
- return set_all_monitor_traces(TRACE_OFF);
+ state = TRACE_OFF;
+ break;
+
+ default:
+ return -ENOTSUPP;
}
- return -ENOTSUPP;
+ mutex_lock(&ns_dm_cb->ns_dm_mutex);
+ if (state == ns_dm_cb->trace_state) {
+ mutex_unlock(&ns_dm_cb->ns_dm_mutex);
+ return -EAGAIN;
+ }
+
+ if (set_all_monitor_traces(state) != 0) {
+ mutex_unlock(&ns_dm_cb->ns_dm_mutex);
+ return -ENOTSUPP;
+ }
+
+ ns_dm_cb->trace_state = state;
+ mutex_unlock(&ns_dm_cb->ns_dm_mutex);
+
+ return 0;
}
static int dropmon_net_event(struct notifier_block *ev_block,
unsigned long event, void *ptr)
{
- struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+ struct net *net;
+ struct net_device *dev;
struct dm_hw_stat_delta *new_stat = NULL;
struct dm_hw_stat_delta *tmp;
+ struct per_ns_dm_cb *ns_dm_cb;
+
+ dev = netdev_notifier_info_to_dev(ptr);
+ if (!dev)
+ goto out;
+
+ net = dev_net(dev);
+ ns_dm_cb = net_generic(net, dm_net_id);
+ if (!ns_dm_cb)
+ goto out;
switch (event) {
case NETDEV_REGISTER:
@@ -350,7 +410,7 @@ static int dropmon_net_event(struct notifier_block
*ev_block,
list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) {
if (new_stat->dev == dev) {
new_stat->dev = NULL;
- if (trace_state == TRACE_OFF) {
+ if (ns_dm_cb->trace_state == TRACE_OFF) {
list_del_rcu(&new_stat->list);
kfree_rcu(new_stat, rcu);
break;
@@ -402,6 +462,7 @@ static int __net_init dm_net_init(struct net *net)
if (!ns_dm_cb)
return -ENOMEM;
+ ns_dm_cb->trace_state = TRACE_OFF;
return 0;
}
@@ -432,6 +493,7 @@ static int __init init_net_drop_monitor(void)
pr_err("Unable to store program counters on this arch, Drop
monitor failed\n");
return -ENOSPC;
}
+ dm_trace_ref = 0;
rc = register_pernet_subsys(&dm_net_ops);
rc = genl_register_family(&net_drop_monitor_family);
--
1.8.3.1
