Re: [kvm-devel] [patch 2/6] mmu_notifier: Callbacks to invalidate address ranges

Christoph Lameter
2008-01-31T02:51:38Z

On Thu, 31 Jan 2008, Andrea Arcangeli wrote:

> On Wed, Jan 30, 2008 at 06:08:14PM -0800, Christoph Lameter wrote:
> > hlist_for_each_entry_safe_rcu(mn, n, t,
> ^^^^
>
> > &mm->mmu_notifier.head, hlist) {
> > hlist_del_rcu(&mn->hlist);
> ^^^^
>
> _rcu can go away from both, if hlist_del_rcu can be called w/o locks.

True. hlist_del_init ok? That would allow to check the driver that the
mmu_notifier is already linked in using !hlist_unhashed(). Driver then
needs to properly initialize the mmu_notifier list with INIT_HLIST_NODE().