[RFC, PATCH 12/22] mm: Do no merge vma with different encryption KeyIDs

[Kirill A. Shutemov]

VMAs with different KeyID do not mix together. Only VMAs with the same
KeyID are compatible.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
 include/linux/mm.h | 7 +++++++
 mm/mmap.c          | 3 ++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index bc7b32d0189b..7a4285f09c99 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1486,6 +1486,13 @@ static inline bool vma_is_encrypted(struct vm_area_struct *vma)
 }
 #endif
 
+#ifndef vma_keyid
+static inline int vma_keyid(struct vm_area_struct *vma)
+{
+	return 0;
+}
+#endif
+
 #ifdef CONFIG_SHMEM
 /*
  * The vma_is_shmem is not inline because it is used only by slow
diff --git a/mm/mmap.c b/mm/mmap.c
index 9efdc021ad22..fa218d1c6bfa 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1208,7 +1208,8 @@ static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *
 		mpol_equal(vma_policy(a), vma_policy(b)) &&
 		a->vm_file == b->vm_file &&
 		!((a->vm_flags ^ b->vm_flags) & ~(VM_READ|VM_WRITE|VM_EXEC|VM_SOFTDIRTY)) &&
-		b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT);
+		b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT) &&
+		vma_keyid(a) == vma_keyid(b);
 }
 
 /*
-- 
2.16.1