On Fri, Nov 03, 2023 at 05:20:53PM +0100, Stefano Brivio wrote:
> On Thu, 12 Oct 2023 12:51:06 +1100
> David Gibson <david@gibson.dropbear.id.au> wrote:
> 
> > tcp_splice_epoll_ctl() removes both sockets from the epoll set if called
> > when conn->flags & CLOSING.  This will always happen immediately after
> > setting that flag, since conn_flag_do() makes the call itself.  That's also
> > the _only_ time it can happen: we perform the EPOLL_CTL_DEL without
> > clearing the conn->in_epoll flag, meaning that any further calls to
> > tcp_splice_epoll_ctl() would attempt EPOLL_CTL_MOD, which would necessarily
> > fail since the fds are no longer in the epoll.
> > 
> > The EPOLL_CTL_DEL path in tcp_splice_epoll_ctl() has essentially zero
> > overlap with anything else the function does, so just move them to be
> > open coded in conn_flag_do().
> > 
> > Caveat: this does require kernel 2.6.9 or later, in order to pass NULL as
> > the event structure for epoll_ctl().  I _think_ we already require newer
> > kernels than that for other features.
> 
> Yes, we do, we need at least 3.13 for unprivileged user namespaces.

Thanks, message updated accordingly.


-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson