v4.19.13 snapshot.
diff --git a/include/linux/vmacache.h b/include/linux/vmacache.h
new file mode 100644
index 0000000..6fce268
--- /dev/null
+++ b/include/linux/vmacache.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LINUX_VMACACHE_H
+#define __LINUX_VMACACHE_H
+
+#include <linux/sched.h>
+#include <linux/mm.h>
+
+static inline void vmacache_flush(struct task_struct *tsk)
+{
+ memset(tsk->vmacache.vmas, 0, sizeof(tsk->vmacache.vmas));
+}
+
+extern void vmacache_update(unsigned long addr, struct vm_area_struct *newvma);
+extern struct vm_area_struct *vmacache_find(struct mm_struct *mm,
+ unsigned long addr);
+
+#ifndef CONFIG_MMU
+extern struct vm_area_struct *vmacache_find_exact(struct mm_struct *mm,
+ unsigned long start,
+ unsigned long end);
+#endif
+
+static inline void vmacache_invalidate(struct mm_struct *mm)
+{
+ mm->vmacache_seqnum++;
+}
+
+#endif /* __LINUX_VMACACHE_H */