On Sat, Aug 28, 2021 at 09:04:41AM +0800, Li Zhijian wrote: > + if (!pte_devmap(pte) && pte_special(pte) && > + !is_zero_pfn(pte_pfn(pte))) { Maybe this is a little too superficial and nitpicky, but I find the ordering of the checks a little strange. Why not do the pte_special first and then the exlusions from it later?