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authorMike Rapoport <rppt@linux.vnet.ibm.com>2017-02-23 02:43:28 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-23 03:41:28 +0300
commitb0506e488da5cf2f07f3a4f6d7acaa8f459ad714 (patch)
treecad7fd2c8c6e3a5d762824925bc6e468dc02ccb6 /include/linux/mm.h
parent4c27fe4c4c84f3afd504ecff2420cc1ad420d38e (diff)
downloadlinux-b0506e488da5cf2f07f3a4f6d7acaa8f459ad714.tar.xz
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 'include/linux/mm.h')
-rw-r--r--include/linux/mm.h10
1 files changed, 10 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h
index c3e2be2b3296..bb997493e15d 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1383,6 +1383,16 @@ static inline bool vma_is_anonymous(struct vm_area_struct *vma)
return !vma->vm_ops;
}
+#ifdef CONFIG_SHMEM
+/*
+ * The vma_is_shmem is not inline because it is used only by slow
+ * paths in userfault.
+ */
+bool vma_is_shmem(struct vm_area_struct *vma);
+#else
+static inline bool vma_is_shmem(struct vm_area_struct *vma) { return false; }
+#endif
+
static inline int stack_guard_page_start(struct vm_area_struct *vma,
unsigned long addr)
{