On Tue, Jun 12, 2018 at 11:15:28AM +0800, Huang, Ying wrote: > "Huang, Ying" <ying.huang@xxxxxxxxx> writes: > >> On Wed, May 23, 2018 at 04:26:07PM +0800, Huang, Ying wrote: > >>> @@ -3516,11 +3512,39 @@ static int __swap_duplicate(swp_entry_t entry, unsigned char usage) > >> > >> Two comments about this part of __swap_duplicate as long as you're moving it to > >> another function: > >> > >> } else if (count || has_cache) { > >> > >> if ((count & ~COUNT_CONTINUED) < SWAP_MAP_MAX) /* #1 */ > >> count += usage; > >> else if ((count & ~COUNT_CONTINUED) > SWAP_MAP_MAX) /* #2 */ > >> err = -EINVAL; > >> > >> #1: __swap_duplicate_locked might use > >> > >> VM_BUG_ON(usage != SWAP_HAS_CACHE && usage != 1); > >> > >> to document the unstated assumption that usage is 1 (otherwise count could > >> overflow). > > > > Sounds good. Will do this. > > Found usage parameter of __swap_duplicate() could be SWAP_MAP_SHMEM too. > We can improve the parameter checking. But that appears not belong to > this series. Fair enough, I'll see about adding this along with the other patch I'm sending. Daniel