1 files changed, 30 insertions, 0 deletions
diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
index dc1a54826cf2..a23001a22c15 100644
--- a/mm/page_vma_mapped.c
+++ b/mm/page_vma_mapped.c
@@ -186,3 +186,33 @@ next_pte:	do {
 		}
 	}
 }
+
+/**
+ * page_mapped_in_vma - check whether a page is really mapped in a VMA
+ * @page: the page to test
+ * @vma: the VMA to test
+ *
+ * Returns 1 if the page is mapped into the page tables of the VMA, 0
+ * if the page is not mapped into the page tables of this VMA.  Only
+ * valid for normal file or anonymous VMAs.
+ */
+int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma)
+{
+	struct page_vma_mapped_walk pvmw = {
+		.page = page,
+		.vma = vma,
+		.flags = PVMW_SYNC,
+	};
+	unsigned long start, end;
+
+	start = __vma_address(page, vma);
+	end = start + PAGE_SIZE * (hpage_nr_pages(page) - 1);
+
+	if (unlikely(end < vma->vm_start || start >= vma->vm_end))
+		return 0;
+	pvmw.address = max(start, vma->vm_start);
+	if (!page_vma_mapped_walk(&pvmw))
+		return 0;
+	page_vma_mapped_walk_done(&pvmw);
+	return 1;
+}