--- zzzz-none-000/linux-4.4.60/include/linux/vmacache.h	2017-04-08 07:53:53.000000000 +0000
+++ jet-2400-727/linux-4.4.60/include/linux/vmacache.h	2021-03-17 14:36:41.000000000 +0000
@@ -15,7 +15,6 @@
 	memset(tsk->vmacache, 0, sizeof(tsk->vmacache));
 }
 
-extern void vmacache_flush_all(struct mm_struct *mm);
 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);
@@ -29,10 +28,6 @@
 static inline void vmacache_invalidate(struct mm_struct *mm)
 {
 	mm->vmacache_seqnum++;
-
-	/* deal with overflows */
-	if (unlikely(mm->vmacache_seqnum == 0))
-		vmacache_flush_all(mm);
 }
 
 #endif /* __LINUX_VMACACHE_H */