Re: [PATCH v2 1/1] s390/crash: allow multi-segment iterators

[Al Viro]

On Thu, Jul 07, 2022 at 08:01:15AM +0200, Alexander Gordeev wrote:
> Rework copy_oldmem_page() to allow multi-segment iterators.
> Reuse existing iterate_iovec macro as is and only relevant
> bits from __iterate_and_advance macro.
> 
> Fixes: 49b11524d648 ("s390/crash: add missing iterator advance in copy_oldmem_page())
> Signed-off-by: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>

To be followed by duplication of every change ever done to those macros?
Hell, no.  Do it the same way it's done for that _copy_from_iter_flushcache()
thing - i.e. an ifdef in lib/iov_iter.c and no duplication of that forest of
macros.