On Fri, Mar 18, 2022 at 05:55:30PM +0800, Xiaoguang Wang wrote: > Module target_core_user will use it to implement zero copy feature. > > Signed-off-by: Xiaoguang Wang <xiaoguang.wang@xxxxxxxxxxxxxxxxx> > --- > mm/memory.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/mm/memory.c b/mm/memory.c > index 1f745e4d11c2..9974d0406dad 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -1664,6 +1664,7 @@ void zap_page_range(struct vm_area_struct *vma, unsigned long start, > mmu_notifier_invalidate_range_end(&range); > tlb_finish_mmu(&tlb); > } > +EXPORT_SYMBOL_GPL(zap_page_range); BTW, what is the counter part api of remap_pfn_range() for serving the unmap? Or does it really need to unmap the vm space for this zero-copy case? If it isn't necessary to unmap, maybe remap_pfn_range() is faster than vm_insert_page(s)_mkspecial + zap_page_range() since zap_page_range() looks a bit heavy. Thanks, Ming
