On Sun, May 08, 2022 at 09:09:55PM +0800, Baolin Wang wrote: > > > On 5/8/2022 7:09 PM, Muchun Song wrote: > > 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> > > Thanks for reviewing. > > > > > 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? > > I did not meet any warning without the casting, but this is per Mike's > comment[1] to make the code consistent with other functions casting to void > type explicitly in hugetlb.c file. > Got it. I see hugetlb.c per this rule, while others do not. > [1] > https://lore.kernel.org/all/495c4ebe-a5b4-afb6-4cb0-956c1b18d0cc@xxxxxxxxxx/ >
