On 26.06.2019 21:34, Jakub Kicinski wrote:
> On Wed, 26 Jun 2019 21:15:15 +0300, Ilya Maximets wrote:
>> diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
>> index 267b82a4cbcf..56729e74cbea 100644
>> --- a/net/xdp/xdp_umem.c
>> +++ b/net/xdp/xdp_umem.c
>> @@ -140,34 +140,38 @@ int xdp_umem_assign_dev(struct xdp_umem *umem, struct net_device *dev,
>> return err;
>> }
>>
>> -static void xdp_umem_clear_dev(struct xdp_umem *umem)
>> +void xdp_umem_clear_dev(struct xdp_umem *umem)
>> {
>> + bool lock = rtnl_is_locked();
>
> How do you know it's not just locked by someone else? You need to pass
> the locked state in if this is called from different paths, some of
> which already hold rtnl.
Oh. That's a shame. I need more sleep.
Thanks for spotting. I'll re-work this part.
Best regards, Ilya Maximets.
>
> Preferably factor the code which needs the lock out into a separate
> function like this:
>
> void __function()
> {
> do();
> the();
> things();
> under();
> the();
> lock();
> }
>
> void function()
> {
> rtnl_lock();
> __function();
> rtnl_unlock();
> }
>
>> struct netdev_bpf bpf;
>> int err;
>>
>> + if (!lock)
>> + rtnl_lock();
>
>
>
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