On Wed 10-03-21 20:28:07, Jason Gunthorpe wrote: > On Wed, Mar 10, 2021 at 01:31:17PM -0800, Sean Christopherson wrote: > > Invoke the MMU notifier's .invalidate_range_end() callbacks even if one > > of the .invalidate_range_start() callbacks failed. If there are multiple > > notifiers, the notifier that did not fail may have performed actions in > > its ...start() that it expects to unwind via ...end(). Per the > > mmu_notifier_ops documentation, ...start() and ...end() must be paired. > > No this is not OK, if invalidate_start returns EBUSY invalidate_end > should *not* be called. Yes, this is what I remember when introducing nonblock interface. So I agree with Jason this patch is not correct. The interface is subtle but I remember we couldn't come up with something more robust and still memory with notifiers to be reapable. -- Michal Hocko SUSE Labs
