David Laight <David.Laight@xxxxxxxxxx> wrote: > > Couldn't the relevant code directly call __copy_from_iter_mc() ? > Or a version then checked iov_is_copy_mc() and then fell > back to the standard function. No, because the marked iterator is handed by the coredump code to __kernel_write_iter() and thence on to who-knows-what driver - which will call copy_from_iter() or some such. $DRIVER shouldn't need to know about ->copy_mc. One thing I do wonder about, though, is what should happen if they call, say, csum_and_copy_from_iter()? That doesn't have an _mc variant. Or what if they extract the pages and operate directly on those? David
