On Tue, 23 May 2023, Alistair Popple wrote: > > Hugh Dickins <hughd@xxxxxxxxxx> writes: > > > migration_entry_wait_on_locked() does not need to take a mapped pte > > pointer, its callers can do the unmap first. Annotate it with > > __releases(ptl) to reduce sparse warnings. > > Thanks Hugh, I debated doing something similar when I reworked this to > not take a pageref. However I was unsure if the pte unmap/unlock > ordering mattered as this reverses the order of operations (from unlock > then unmap to unmap then unlock). > > I never found any reason why that would be a problem though so please > add: > > Reviewed-by: Alistair Popple <apopple@xxxxxxxxxx> Thanks Alistair. Right, the ordering doesn't matter: you might briefly think that because I'm going to put the rcu_read_unlock() into the pte_unmap(), that there's something wrong with doing that early; but you'd quickly realize that holding on to the spinlock is good enough. Hugh
