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authorMike Rapoport <rppt@linux.vnet.ibm.com>2017-02-22 15:43:28 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-22 16:41:28 -0800
commitb0506e488da5cf2f07f3a4f6d7acaa8f459ad714 (patch)
treecad7fd2c8c6e3a5d762824925bc6e468dc02ccb6 /mm/shmem.c
parent4c27fe4c4c84f3afd504ecff2420cc1ad420d38e (diff)
downloadlwn-b0506e488da5cf2f07f3a4f6d7acaa8f459ad714.tar.gz
lwn-b0506e488da5cf2f07f3a4f6d7acaa8f459ad714.zip
userfaultfd: shmem: introduce vma_is_shmem
Currently userfault relies on vma_is_anonymous and vma_is_hugetlb to ensure compatibility of a VMA with userfault. Introduction of vma_is_shmem allows detection if tmpfs backed VMAs, so that they may be used with userfaultfd. Current implementation presumes usage of vma_is_shmem only by slow path routines in userfaultfd, therefore the vma_is_shmem is not made inline to leave the few remaining free bits in vm_flags. Link: http://lkml.kernel.org/r/20161216144821.5183-30-aarcange@redhat.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Michael Rapoport <RAPOPORT@il.ibm.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/shmem.c')
-rw-r--r--mm/shmem.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/mm/shmem.c b/mm/shmem.c
index 14de2a9e5083..8412baec17cd 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -191,6 +191,11 @@ static const struct inode_operations shmem_special_inode_operations;
static const struct vm_operations_struct shmem_vm_ops;
static struct file_system_type shmem_fs_type;
+bool vma_is_shmem(struct vm_area_struct *vma)
+{
+ return vma->vm_ops == &shmem_vm_ops;
+}
+
static LIST_HEAD(shmem_swaplist);
static DEFINE_MUTEX(shmem_swaplist_mutex);