2023-08-04 08:58:12

by Yang Yang

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

From: xu xin <[email protected]>

Add net device refcount tracker to udp_tunnel_nic.c.

Signed-off-by: xu xin <[email protected]>
Reviewed-by: Yang Yang <[email protected]>
Cc: Kuang Mingfu <[email protected]>
---
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

2023-08-04 11:16:04

by Eric Dumazet

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

On Fri, Aug 4, 2023 at 10:50 AM <[email protected]> wrote:
>
> From: xu xin <[email protected]>
>
> Add net device refcount tracker to udp_tunnel_nic.c.
>
> Signed-off-by: xu xin <[email protected]>
> Reviewed-by: Yang Yang <[email protected]>
> Cc: Kuang Mingfu <[email protected]>
> ---
> 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

2023-08-05 07:09:47

by xu xin

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

>> ---
>> 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!