On Mon, Oct 16, 2017 at 4:18 AM, Chris Mi <[email protected]> wrote:
> If many filters share the same action. That action's refcnt and bindcnt
> could be manipulated by many RCU callbacks at the same time. This patch
> makes these operations atomic.
Actually I have been thinking about removing these RCU callbacks,
they are not necessary AFAIK, callers hold RTNL lock so they are
allowed to block. The only drawback is that adding a synchronize_rcu(),
but these are slow paths anyway...
I am not sure, it is arguable anyway, essentially it is:
synchronize_rcu() in slow path vs. multiple RCU callback races
>
> Fixes commit in pre-git era.
>
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
This is not true, the action RCU callbacks were introduced
by:
commit c7de2cf053420d63bac85133469c965d4b1083e1
Author: Eric Dumazet <[email protected]>
Date: Wed Jun 9 02:09:23 2010 +0000
pkt_sched: gen_kill_estimator() rcu fixes
and the filter RCU callbacks were introduced by the
patchset like this one:
commit 1ce87720d456e471de0fbd814dc5d1fe10fc1c44
Author: John Fastabend <[email protected]>
Date: Fri Sep 12 20:09:16 2014 -0700
net: sched: make cls_u32 lockless
