On 22.03.22 14:02, Xiaoguang Wang wrote: > hi, > >> On 18.03.22 10:55, Xiaoguang Wang wrote: >>> Module target_core_user will use it to implement zero copy feature. >>> >>> Signed-off-by: Xiaoguang Wang <xiaoguang.wang@xxxxxxxxxxxxxxxxx> >>> --- >>> mm/memory.c | 1 + >>> 1 file changed, 1 insertion(+) >>> >>> diff --git a/mm/memory.c b/mm/memory.c >>> index 1f745e4d11c2..9974d0406dad 100644 >>> --- a/mm/memory.c >>> +++ b/mm/memory.c >>> @@ -1664,6 +1664,7 @@ void zap_page_range(struct vm_area_struct *vma, unsigned long start, >>> mmu_notifier_invalidate_range_end(&range); >>> tlb_finish_mmu(&tlb); >>> } >>> +EXPORT_SYMBOL_GPL(zap_page_range); >>> >>> /** >>> * zap_page_range_single - remove user pages in a given range >> To which VMAs will you be applying zap_page_range? I assume only to some >> special ones where you previously vm_insert_page(s)_mkspecial'ed pages, >> not to some otherwise random VMAs, correct? > Yes, you're right :) I'd suggest exposing a dedicated function that performs sanity checks on the vma (VM_PFNMAP ?) and only zaps within a single VMA. Essentially zap_page_range_single(), excluding "struct zap_details *details" and including sanity checks. Reason is that we don't want anybody to blindly zap_page_range() within random VMAs from a kernel module. -- Thanks, David / dhildenb
