On Sun, May 08, 2022 at 05:36:39PM +0800, Baolin Wang wrote: > It is incorrect to use ptep_clear_flush() to nuke a hugetlb page > table when unmapping or migrating a hugetlb page, and will change > to use huge_ptep_clear_flush() instead in the following patches. > > So this is a preparation patch, which changes the huge_ptep_clear_flush() > to return the original pte to help to nuke a hugetlb page table. > > Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> > Acked-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Reviewed-by: Muchun Song <songmuchun@xxxxxxxxxxxxx> But one nit below: [...] > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 8605d7e..61a21af 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -5342,7 +5342,7 @@ static vm_fault_t hugetlb_wp(struct mm_struct *mm, struct vm_area_struct *vma, > ClearHPageRestoreReserve(new_page); > > /* Break COW or unshare */ > - huge_ptep_clear_flush(vma, haddr, ptep); > + (void)huge_ptep_clear_flush(vma, haddr, ptep); Why add a "(void)" here? Is there any warning if no "(void)"? IIUC, I think we can remove this, right? > mmu_notifier_invalidate_range(mm, range.start, range.end); > page_remove_rmap(old_page, vma, true); > hugepage_add_new_anon_rmap(new_page, vma, haddr); > -- > 1.8.3.1 > >
