[PATCH v2 0/2] Allow gmap fault to retry

[Dominik Dingel <dingel@linux.vnet.ibm.com>]

Hello,

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 needs some fix.

Thanks,
    Dominik

v1 -> v2:
- Instead of passing the VM_FAULT_RETRY from fixup_user_fault we do retries
  within fixup_user_fault, like get_user_pages_locked do.
- gmap code will now take retry if fixup_user_fault drops the lock

Dominik Dingel (2):
  mm: bring in additional flag for fixup_user_fault to signal unlock
  s390/mm: enable fixup_user_fault retrying

 arch/s390/mm/pgtable.c | 31 ++++++++++++++++++++++++++++---
 include/linux/mm.h     |  5 +++--
 kernel/futex.c         |  2 +-
 mm/gup.c               | 25 +++++++++++++++++++++----
 4 files changed, 53 insertions(+), 10 deletions(-)

-- 
2.3.9

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