Re: [PATCH v3 2/2] iov_iter: Don't deal with iter->copy_mc in memcpy_from_iter_mc()

[Matthew Wilcox]

On Fri, Aug 18, 2023 at 12:16:23PM +0000, David Laight wrote:
> > > +	ITER_IOVEC = 1,
> > > +	ITER_UBUF = 2,
> > > +	ITER_KVEC = 4,
> > > +	ITER_BVEC = 8,
> > > +	ITER_XARRAY = 16,
> > > +	ITER_DISCARD = 32,
> 
> IIRC Linus had type:6 - that doesn't leave any headroom
> for additional types (even though they shouldn't proliferate).

I have proposed an ITER_KBUF in the past (it is to KVEC as UBUF is
to IOVEC).  I didn't care enough to keep pushing it, but it's clearly
a common idiom.