Re: [PATCH] tiny af_packet.c cleanup

[Mitchell Blank Jr <mitch@xxxxxxxxxx>]

Francois Romieu wrote:
> Actually packet_rcv() is run in a BH context and doesn't race with
> SO_{ATTACH/DETACH}_FILTER from sock_setsockopt() which does the
> appropriate BH locking (spin_lock_bh(&sk->sk_lock.slock) in
> net/core/sock.c::sock_setsockopt and in net/core/filter.c::sk_attach_filter).
> packet_rcv() doesn't race with BH either due to the bh_lock_sock (a spin_lock
> in disguise) you quoted.

I don't understand what you're saying - are you saying that the locking
isn't needed?  Or just the recheck isn't needed?  It sounds like if we're
only avoiding the race because of the bh_lock_sock() then we do need to
recheck, right?

Could you do a patch for what you think it should look like?  You obviously
understand the locking issues here better than I.

-Mitch