userfaultfd: non-cooperative: add madvise() event for MADV_DONTNEED request
If the page is punched out of the address space the uffd reader should
know this and zeromap the respective area in case of the #PF event.
Link: http://lkml.kernel.org/r/20161216144821.5183-14-aarcange@redhat.com
Signed-off-by: Pavel Emelyanov <xemul@parallels.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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h
index 78ec197..f431861 100644
--- a/include/linux/userfaultfd_k.h
+++ b/include/linux/userfaultfd_k.h
@@ -61,6 +61,11 @@
unsigned long from, unsigned long to,
unsigned long len);
+extern void madvise_userfault_dontneed(struct vm_area_struct *vma,
+ struct vm_area_struct **prev,
+ unsigned long start,
+ unsigned long end);
+
#else /* CONFIG_USERFAULTFD */
/* mm helpers */
@@ -106,6 +111,13 @@
unsigned long len)
{
}
+
+static inline void madvise_userfault_dontneed(struct vm_area_struct *vma,
+ struct vm_area_struct **prev,
+ unsigned long start,
+ unsigned long end)
+{
+}
#endif /* CONFIG_USERFAULTFD */
#endif /* _LINUX_USERFAULTFD_K_H */