[PATCH RFC 0/3] MAP_POPULATE for device memory

[Jarkko Sakkinen <jarkko@kernel.org>]

For device memory (aka VM_IO | VM_PFNMAP) MAP_POPULATE does nothing. Allow
to use that for initializing the device memory by providing a new callback
f_ops->populate() for the purpose.

SGX patches are provided to show the callback in context.

An obvious alternative is a ioctl but it is less elegant and requires
two syscalls (mmap + ioctl) per memory range, instead of just one
(mmap).

Jarkko Sakkinen (3):
  mm: Add f_ops->populate()
  x86/sgx: Export sgx_encl_page_alloc()
  x86/sgx: Implement EAUG population with MAP_POPULATE

 arch/mips/kernel/vdso.c                    |   2 +-
 arch/x86/kernel/cpu/sgx/driver.c           | 129 +++++++++++++++++++++
 arch/x86/kernel/cpu/sgx/encl.c             |  38 ++++++
 arch/x86/kernel/cpu/sgx/encl.h             |   3 +
 arch/x86/kernel/cpu/sgx/ioctl.c            |  38 ------
 drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c |   2 +-
 fs/coda/file.c                             |   2 +-
 fs/overlayfs/file.c                        |   2 +-
 include/linux/fs.h                         |  12 +-
 include/linux/mm.h                         |   2 +-
 ipc/shm.c                                  |   2 +-
 mm/mmap.c                                  |  10 +-
 mm/nommu.c                                 |   4 +-
 13 files changed, 193 insertions(+), 53 deletions(-)

-- 
2.35.1