Subject: Re: [PATCH] netfilter: nf_conntrack: use safer way to lock all buckets

From: Sasha Levin <[email-masked]>
Date: Wed, 13 Jan 2016 13:37:33 -0500

On 01/13/2016 11:54 AM, Pablo Neira Ayuso wrote:
> On Sun, Jan 10, 2016 at 02:06:37AM +0100, Florian Westphal wrote:
>> > Sasha Levin <[email-masked]> wrote:
>>> > > Fix this by using a global lock and synchronize all buckets on it when we
>>> > > need to lock them all. This is pretty heavyweight, but is only done when we
>>> > > need to resize the hashtable, and that doesn't happen often enough (or at all).
>> > 
>>> > > diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
>>> > > index 3cb3cb8..3c008ce 100644
>>> > > --- a/net/netfilter/nf_conntrack_core.c
>>> > > +++ b/net/netfilter/nf_conntrack_core.c
>>> > > @@ -66,6 +66,32 @@ EXPORT_SYMBOL_GPL(nf_conntrack_locks);
>>> > >  __cacheline_aligned_in_smp DEFINE_SPINLOCK(nf_conntrack_expect_lock);
>>> > >  EXPORT_SYMBOL_GPL(nf_conntrack_expect_lock);
>>> > >  
>>> > > +spinlock_t nf_conntrack_locks_all_lock;
>>> > > +bool nf_conntrack_locks_all;
>> > 
>> > Seems both of these can be static and __read_mostly too --
>> > as you already note resizing virtually never happens.
>> >
>> > Otherwise:
>> > Reviewed-by: Florian Westphal <[email-masked]>
> Sasha, would you resubmit addressing Florian's feedback?

Yup, sorry - still catching up with the holidays vacation :(

Thanks,
Sasha