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authorDan Williams <dan.j.williams@intel.com>2017-11-29 16:10:28 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-12-05 11:24:32 +0100
commitcebe139e5712d6925a9b70f3769df6818b6c14dd (patch)
tree19459df40421d982cc432861ea7c3ab64cb6ea6f /mm/mmap.c
parent436f19a2e49e57b39e1d46ee018eb5f64ec1031f (diff)
mm, hugetlbfs: introduce ->split() to vm_operations_struct
commit 31383c6865a578834dd953d9dbc88e6b19fe3997 upstream. 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> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm/mmap.c')
-rw-r--r--mm/mmap.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index 75d263bd8739..5b48adb4aa56 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2538,9 +2538,11 @@ static int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
struct vm_area_struct *new;
int err;
- if (is_vm_hugetlb_page(vma) && (addr &
- ~(huge_page_mask(hstate_vma(vma)))))
- return -EINVAL;
+ if (vma->vm_ops && vma->vm_ops->split) {
+ err = vma->vm_ops->split(vma, addr);
+ if (err)
+ return err;
+ }
new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
if (!new)