[PATCH V3 0/7] Add FOLL_LONGTERM to GUP fast and use it

[ira . weiny]

From: Ira Weiny <ira.weiny@xxxxxxxxx>

Following discussion and review[1] here are the cleanups requested.

The biggest change for V3 was the disabling of the ability to use FOLL_LONGTERM
in get_user_pages[unlocked|locked|remote]

Comments were also enhanced throughout to show potential users what
FOLL_LONGTERM is all about and limitations it has.

Minor review comments were fixed

Original cover letter:

HFI1, qib, and mthca, use get_user_pages_fast() due to it performance
advantages.  These pages can be held for a significant time.  But
get_user_pages_fast() does not protect against mapping FS DAX pages.

Introduce FOLL_LONGTERM and use this flag in get_user_pages_fast() which
retains the performance while also adding the FS DAX checks.  XDP has also
shown interest in using this functionality.[1]

In addition we change get_user_pages() to use the new FOLL_LONGTERM flag and
remove the specialized get_user_pages_longterm call.

[1] https://lkml.org/lkml/2019/3/19/939



Ira Weiny (7):
  mm/gup: Replace get_user_pages_longterm() with FOLL_LONGTERM
  mm/gup: Change write parameter to flags in fast walk
  mm/gup: Change GUP fast to use flags rather than a write 'bool'
  mm/gup: Add FOLL_LONGTERM capability to GUP fast
  IB/hfi1: Use the new FOLL_LONGTERM flag to get_user_pages_fast()
  IB/qib: Use the new FOLL_LONGTERM flag to get_user_pages_fast()
  IB/mthca: Use the new FOLL_LONGTERM flag to get_user_pages_fast()

 arch/mips/mm/gup.c                          |  11 +-
 arch/powerpc/kvm/book3s_64_mmu_hv.c         |   4 +-
 arch/powerpc/kvm/e500_mmu.c                 |   2 +-
 arch/powerpc/mm/mmu_context_iommu.c         |   3 +-
 arch/s390/kvm/interrupt.c                   |   2 +-
 arch/s390/mm/gup.c                          |  12 +-
 arch/sh/mm/gup.c                            |  11 +-
 arch/sparc/mm/gup.c                         |   9 +-
 arch/x86/kvm/paging_tmpl.h                  |   2 +-
 arch/x86/kvm/svm.c                          |   2 +-
 drivers/fpga/dfl-afu-dma-region.c           |   2 +-
 drivers/gpu/drm/via/via_dmablit.c           |   3 +-
 drivers/infiniband/core/umem.c              |   5 +-
 drivers/infiniband/hw/hfi1/user_pages.c     |   3 +-
 drivers/infiniband/hw/mthca/mthca_memfree.c |   3 +-
 drivers/infiniband/hw/qib/qib_user_pages.c  |   8 +-
 drivers/infiniband/hw/qib/qib_user_sdma.c   |   2 +-
 drivers/infiniband/hw/usnic/usnic_uiom.c    |   9 +-
 drivers/media/v4l2-core/videobuf-dma-sg.c   |   6 +-
 drivers/misc/genwqe/card_utils.c            |   2 +-
 drivers/misc/vmw_vmci/vmci_host.c           |   2 +-
 drivers/misc/vmw_vmci/vmci_queue_pair.c     |   6 +-
 drivers/platform/goldfish/goldfish_pipe.c   |   3 +-
 drivers/rapidio/devices/rio_mport_cdev.c    |   4 +-
 drivers/sbus/char/oradax.c                  |   2 +-
 drivers/scsi/st.c                           |   3 +-
 drivers/staging/gasket/gasket_page_table.c  |   4 +-
 drivers/tee/tee_shm.c                       |   2 +-
 drivers/vfio/vfio_iommu_spapr_tce.c         |   3 +-
 drivers/vfio/vfio_iommu_type1.c             |   3 +-
 drivers/vhost/vhost.c                       |   2 +-
 drivers/video/fbdev/pvr2fb.c                |   2 +-
 drivers/virt/fsl_hypervisor.c               |   2 +-
 drivers/xen/gntdev.c                        |   2 +-
 fs/io_uring.c                               |   5 +-
 fs/orangefs/orangefs-bufmap.c               |   2 +-
 include/linux/mm.h                          |  45 ++-
 kernel/futex.c                              |   2 +-
 lib/iov_iter.c                              |   7 +-
 mm/gup.c                                    | 288 +++++++++++++-------
 mm/gup_benchmark.c                          |   5 +-
 mm/util.c                                   |   8 +-
 net/ceph/pagevec.c                          |   2 +-
 net/rds/info.c                              |   2 +-
 net/rds/rdma.c                              |   3 +-
 net/xdp/xdp_umem.c                          |   4 +-
 46 files changed, 314 insertions(+), 200 deletions(-)

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2.20.1