From: David Howells > Sent: Wednesday, August 16, 2023 1:08 PM Given: > iter->copy_mc is only used with a bvec iterator and only by > dump_emit_page() in fs/coredump.c so rather than handle this in > memcpy_from_iter_mc() where it is checked repeatedly by _copy_from_iter() and > copy_page_from_iter_atomic(), Instead of adding the extra check to every copy: > +static __always_inline > +size_t __copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) > +{ > + if (unlikely(iov_iter_is_copy_mc(i))) > + return __copy_from_iter_mc(addr, bytes, i); > + return iterate_and_advance(i, bytes, addr, > + copy_from_user_iter, memcpy_from_iter); > } Couldn't the relevant code directly call __copy_frtom_iter_mc() ? Or a version then checked iov_is_copy_mc() and then fell back to the standard function. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)