On 12/5/25 19:35, John Hubbard wrote: > On 12/5/25 8:58 AM, Kalyazin, Nikita wrote: >> From: Patrick Roy <[email protected]> >> >> Add AS_NO_DIRECT_MAP for mappings where direct map entries of folios are >> set to not present. Currently, mappings that match this description are >> secretmem mappings (memfd_secret()). Later, some guest_memfd >> configurations will also fall into this category. >> >> Reject this new type of mappings in all locations that currently reject >> secretmem mappings, on the assumption that if secretmem mappings are >> rejected somewhere, it is precisely because of an inability to deal with >> folios without direct map entries, and then make memfd_secret() use >> AS_NO_DIRECT_MAP on its address_space to drop its special >> vma_is_secretmem()/secretmem_mapping() checks. >> >> This drops a optimization in gup_fast_folio_allowed() where >> secretmem_mapping() was only called if CONFIG_SECRETMEM=y. secretmem is >> enabled by default since commit b758fe6df50d ("mm/secretmem: make it on >> by default"), so the secretmem check did not actually end up elided in >> most cases anymore anyway. > > The above paragraph can be part (most) of a commit description for > a separate patch for the gup aspects. Let's split it out that way, > because it is a distinct change, and the diffs can stand alone > from this patch here.
I assume the separated gup change will be ordered as the earlier one, because keeping "check_secretmem" together with newly checking mapping_no_direct_map() would be incorrect. Make sense. > thanks,
