diff --git a/include/linux/mm.h b/include/linux/mm.h
index a55e5be..0ef9dc72 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -299,6 +299,12 @@
 					 * is set (which is also implied by
 					 * VM_FAULT_ERROR).
 					 */
+	void *entry;			/* ->fault handler can alternatively
+					 * return locked DAX entry. In that
+					 * case handler should return
+					 * VM_FAULT_DAX_LOCKED and fill in
+					 * entry here.
+					 */
 	/* for ->map_pages() only */
 	pgoff_t max_pgoff;		/* map pages for offset from pgoff till
 					 * max_pgoff inclusive */
@@ -1084,6 +1090,7 @@
 #define VM_FAULT_LOCKED	0x0200	/* ->fault locked the returned page */
 #define VM_FAULT_RETRY	0x0400	/* ->fault blocked, must retry */
 #define VM_FAULT_FALLBACK 0x0800	/* huge page fault failed, fall back to small */
+#define VM_FAULT_DAX_LOCKED 0x1000	/* ->fault has locked DAX entry */
 
 #define VM_FAULT_HWPOISON_LARGE_MASK 0xf000 /* encodes hpage index for large hwpoison */