[PATCH 0/2] Allow gmap fault to retry

From: Dominik Dingel
Date: Wed Nov 18 2015 - 18:51:08 EST


during Jasons work with postcopy migration support for s390 a problem regarding
gmap faults was discovered.

The gmap code will call fixup_userfault which will end up always in
handle_mm_fault. Till now we never cared about retries, but as the userfaultfd
code kind of relies on it, this needed some fix. This patchset includes the
retry logic fory gmap fault scenarios, as well as passing back VM_FAULT_RETRY
from fixup_userfault.


Dominik Dingel (2):
mm: fixup_userfault returns VM_FAULT_RETRY if asked
s390/mm: allow gmap code to retry on faulting in guest memory

arch/s390/mm/pgtable.c | 28 ++++++++++++++++++++++++----
mm/gup.c | 2 ++
2 files changed, 26 insertions(+), 4 deletions(-)


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