Unlike other architectures s390 can not use copyout() and memcopy() for
accessing memory and thus using copy_to_iter() now is not possible. But
a fix is needed, since 'cp' routine as 'core_collector' for kdump service
initiates multi-segment iterator.

The reason iterate_iovec() and __iterate_and_advance() macros copied from
lib/iov_iter.c (thus introducing redundancy) is to avoid custom iterator-
treating in s390 code. I doubt these macros could be turned public (i.e
with a follow-up patch), so the intention is to do it like _copy_to_iter()
does.

Changes since v1:
  - number of bytes left to copy on fail fixed;

Alexander Gordeev (1):
  s390/crash: allow multi-segment iterators

 arch/s390/kernel/crash_dump.c | 65 +++++++++++++++++++++++++++--------
 1 file changed, 50 insertions(+), 15 deletions(-)

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2.34.1