Make sure we copy pages inserted with "vm_insert_page()" on fork
The logic that decides that a fork() might be able to avoid copying a VM
area when it can be re-created by page faults didn't know about the new
vm_insert_page() case.
Also make some things a bit more anal wrt VM_PFNMAP.
Pointed out by Hugh Dickins <hugh@veritas.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/mmap.c b/mm/mmap.c
index 11ca592..64ba4db 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -611,7 +611,7 @@
* If the vma has a ->close operation then the driver probably needs to release
* per-vma resources, so we don't attempt to merge those.
*/
-#define VM_SPECIAL (VM_IO | VM_DONTCOPY | VM_DONTEXPAND | VM_RESERVED)
+#define VM_SPECIAL (VM_IO | VM_DONTCOPY | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP)
static inline int is_mergeable_vma(struct vm_area_struct *vma,
struct file *file, unsigned long vm_flags)