[PATCH 0/5] Do not request a pointer kaddr when not required

[Huaisheng Ye]

From: Huaisheng Ye <yehs1@xxxxxxxxxx>

Some functions within fs/dax and dax/super don't need to get kaddr from
direct_access. Assigning NULL to kaddr to ->direct_access() is more
straightforward and simple than offering a useless local pointer.

So all direct_access() need to check the validity of second rank pointer
kaddr for NULL assignment. If kaddr equals to NULL, it doesn't need to
calculate its value.

* This series are supplement to [PATCH v2 00/14]mm: Asynchronous +
  multithreaded memmap init for ZONE_DEVICE. [1]

[1]: https://lkml.org/lkml/2018/7/16/828

Huaisheng Ye (5):
  libnvdimm, pmem: Allow a NULL-kaddr to ->direct_access()
  tools/testing/nvdimm: Allow a NULL-kaddr to ->direct_access()
  s390, dcssblk: Allow a NULL-kaddr to ->direct_access()
  filesystem-dax: Do not request a pointer kaddr when not required
  dax/super: Do not request a pointer kaddr when not required

 drivers/dax/super.c             | 3 +--
 drivers/nvdimm/pmem.c           | 4 +++-
 drivers/s390/block/dcssblk.c    | 3 ++-
 fs/dax.c                        | 3 +--
 tools/testing/nvdimm/pmem-dax.c | 6 ++++--
 5 files changed, 11 insertions(+), 8 deletions(-)

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1.8.3.1