mm, hugetlbfs: introduce ->split() to vm_operations_struct
authorDan Williams <dan.j.williams@intel.com>
Thu, 30 Nov 2017 00:10:28 +0000 (16:10 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 30 Nov 2017 02:40:42 +0000 (18:40 -0800)
commit31383c6865a578834dd953d9dbc88e6b19fe3997
tree046db228487d9ffc716dcc8185957eb08a650f97
parent95a87982541932503d3f59aba4c30b0bde0a6294
mm, hugetlbfs: introduce ->split() to vm_operations_struct

Patch series "device-dax: fix unaligned munmap handling"

When device-dax is operating in huge-page mode we want it to behave like
hugetlbfs and fail attempts to split vmas into unaligned ranges.  It
would be messy to teach the munmap path about device-dax alignment
constraints in the same (hstate) way that hugetlbfs communicates this
constraint.  Instead, these patches introduce a new ->split() vm
operation.

This patch (of 2):

The device-dax interface has similar constraints as hugetlbfs in that it
requires the munmap path to unmap in huge page aligned units.  Rather
than add more custom vma handling code in __split_vma() introduce a new
vm operation to perform this vma specific check.

Link: http://lkml.kernel.org/r/151130418135.4029.6783191281930729710.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/mm.h
mm/hugetlb.c
mm/mmap.c