[PATCH] udp_tunnel_nic: add net device refcount tracker

[PATCH] udp_tunnel_nic: add net device refcount tracker

[yang.yang29]

From: xu xin <xu.xin16@zte.com.cn>

Add net device refcount tracker to udp_tunnel_nic.c.

Signed-off-by: xu xin <xu.xin16@zte.com.cn>
Reviewed-by: Yang Yang <yang.yang29@zte.com.cn>
Cc: Kuang Mingfu <kuang.mingfu@zte.com.cn>
---
 net/ipv4/udp_tunnel_nic.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/udp_tunnel_nic.c b/net/ipv4/udp_tunnel_nic.c
index 029219749785..ce8f5c82b0a1 100644
--- a/net/ipv4/udp_tunnel_nic.c
+++ b/net/ipv4/udp_tunnel_nic.c
@@ -55,6 +55,9 @@ struct udp_tunnel_nic {
  */
 static struct workqueue_struct *udp_tunnel_nic_workqueue;

+/* To track netdev_hold and netdev_put */
+static netdevice_tracker udp_tunnel_nic_devtracker;
+
 static const char *udp_tunnel_nic_tunnel_type_name(unsigned int type)
 {
 	switch (type) {
@@ -825,7 +828,7 @@ static int udp_tunnel_nic_register(struct net_device *dev)
 	}

 	utn->dev = dev;
-	dev_hold(dev);
+	netdev_hold(dev, &udp_tunnel_nic_devtracker, GFP_KERNEL);
 	dev->udp_tunnel_nic = utn;

 	if (!(info->flags & UDP_TUNNEL_NIC_INFO_OPEN_ONLY))
@@ -879,7 +882,7 @@ udp_tunnel_nic_unregister(struct net_device *dev, struct udp_tunnel_nic *utn)
 	udp_tunnel_nic_free(utn);
 release_dev:
 	dev->udp_tunnel_nic = NULL;
-	dev_put(dev);
+	netdev_put(dev, &udp_tunnel_nic_devtracker);
 }

 static int
-- 
2.15.2

Re: [PATCH] udp_tunnel_nic: add net device refcount tracker

[Eric Dumazet]

On Fri, Aug 4, 2023 at 10:50 AM <yang.yang29@zte.com.cn> wrote:
>
> From: xu xin <xu.xin16@zte.com.cn>
>
> Add net device refcount tracker to udp_tunnel_nic.c.
>
> Signed-off-by: xu xin <xu.xin16@zte.com.cn>
> Reviewed-by: Yang Yang <yang.yang29@zte.com.cn>
> Cc: Kuang Mingfu <kuang.mingfu@zte.com.cn>
> ---
>  net/ipv4/udp_tunnel_nic.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/net/ipv4/udp_tunnel_nic.c b/net/ipv4/udp_tunnel_nic.c
> index 029219749785..ce8f5c82b0a1 100644
> --- a/net/ipv4/udp_tunnel_nic.c
> +++ b/net/ipv4/udp_tunnel_nic.c
> @@ -55,6 +55,9 @@ struct udp_tunnel_nic {
>   */
>  static struct workqueue_struct *udp_tunnel_nic_workqueue;
>
> +/* To track netdev_hold and netdev_put */
> +static netdevice_tracker udp_tunnel_nic_devtracker;

This looks wrong.

> +
>  static const char *udp_tunnel_nic_tunnel_type_name(unsigned int type)
>  {
>         switch (type) {
> @@ -825,7 +828,7 @@ static int udp_tunnel_nic_register(struct net_device *dev)
>         }
>
>         utn->dev = dev;
> -       dev_hold(dev);
> +       netdev_hold(dev, &udp_tunnel_nic_devtracker, GFP_KERNEL);

This is wrong. You need a separate netdevice_tracker per netdev_hold()

For instance, this would need to be in "(struct udp_tunnel_nic)->dev_tracker"


>         dev->udp_tunnel_nic = utn;
>
>         if (!(info->flags & UDP_TUNNEL_NIC_INFO_OPEN_ONLY))
> @@ -879,7 +882,7 @@ udp_tunnel_nic_unregister(struct net_device *dev, struct udp_tunnel_nic *utn)
>         udp_tunnel_nic_free(utn);
>  release_dev:
>         dev->udp_tunnel_nic = NULL;
> -       dev_put(dev);
> +       netdev_put(dev, &udp_tunnel_nic_devtracker);
>  }
>
>  static int
> --
> 2.15.2

Re: [PATCH] udp_tunnel_nic: add net device refcount tracker

[xu]

>> ---
>>  net/ipv4/udp_tunnel_nic.c | 7 +++++--
>>  1 file changed, 5 insertions(+), 2 deletions(-)
>>
>> diff --git a/net/ipv4/udp_tunnel_nic.c b/net/ipv4/udp_tunnel_nic.c
>> index 029219749785..ce8f5c82b0a1 100644
>> --- a/net/ipv4/udp_tunnel_nic.c
>> +++ b/net/ipv4/udp_tunnel_nic.c
>> @@ -55,6 +55,9 @@ struct udp_tunnel_nic {
>>   */
>>  static struct workqueue_struct *udp_tunnel_nic_workqueue;
>>
>> +/* To track netdev_hold and netdev_put */
>> +static netdevice_tracker udp_tunnel_nic_devtracker;
>
>This looks wrong.
>
>> +
>>  static const char *udp_tunnel_nic_tunnel_type_name(unsigned int type)
>>  {
>>         switch (type) {
>> @@ -825,7 +828,7 @@ static int udp_tunnel_nic_register(struct net_device *dev)
>>         }
>>
>>         utn->dev = dev;
>> -       dev_hold(dev);
>> +       netdev_hold(dev, &udp_tunnel_nic_devtracker, GFP_KERNEL);
>
>This is wrong. You need a separate netdevice_tracker per netdev_hold()
>
>For instance, this would need to be in "(struct udp_tunnel_nic)->dev_tracker"

Oh, Sorry, I misunderstand the usage of netdev_hold and its netdevice_tracker.

But cound you please add this this useful information into netdev_hold()' comment,

to prevent others from making the same mistakes with me.

Thanks!