Does rtnl_lock inhibit incoming traffic?

Does rtnl_lock inhibit incoming traffic?

[Oliver Hartkopp]

Hello,

AFAIK the rtnl_lock is used (at least) to protect the configuration of
netdevices and routing tables.

Is the reception of incoming traffic inhibited while the rtnl_lock is set, or
would i need to protect the data structures to be modified with an additional
spinlock_bh() / write_lock_bh()?

Like this one here:

http://lxr.linux.no/#linux+v3.9.4/net/ipv6/ip6mr.c#L1573

Regards,
Oliver

Re: Does rtnl_lock inhibit incoming traffic?

[Eric Dumazet]

On Wed, 2013-05-29 at 21:08 +0200, Oliver Hartkopp wrote:
> Hello,
> 
> AFAIK the rtnl_lock is used (at least) to protect the configuration of
> netdevices and routing tables.
> 
> Is the reception of incoming traffic inhibited while the rtnl_lock is set, or
> would i need to protect the data structures to be modified with an additional
> spinlock_bh() / write_lock_bh()?
> 
> Like this one here:
> 
> http://lxr.linux.no/#linux+v3.9.4/net/ipv6/ip6mr.c#L1573


Reception of incoming traffic is not inhibited by rtnl.

And spinlock_bh()/write_lock_bh() only disable current cpu from
receiving frames, but other cpus can still handle incoming traffic.