On Tue, Aug 17, 2021 at 04:24:43PM +0800, Miaohe Lin wrote: > On 2021/8/17 15:29, HORIGUCHI NAOYA(堀口 直也) wrote: ... > > One question is that according to "grep -r pte_unmap_unlock ." command over > > whole kernel source code, pte_unmap_unlock() is called with "ptep - 1" in some places. > > I think that none of them seems to have "break in for loop" in locked period, > > so the same problem does not occur there. But I'm still not sure why some place > > call with "ptep - 1" and the others call with pte returned by pte_offset_map_lock(). > > IMO pte_unmap_unlock() works as long as the passed in pte belongs to the same page returned > from pte_offset_map_lock(). I have fixed some similar place where pte_unmap_unlock() is called > with wrong "ptep - 1" when I was learning the related mm code. Great, thanks for clarification. - Naoya
