diff --git a/kernel/events/core.c b/kernel/events/core.c
index a4986087977798d8af3f7dfb485c1f46b0dbbad0..a1f12009e5efe47708f014fba7b7a4ee43318e2b 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -5760,7 +5760,7 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
 again:
 	mutex_lock(&event->mmap_mutex);
 	if (event->rb) {
-		if (event->rb->nr_pages != nr_pages) {
+		if (data_page_nr(event->rb) != nr_pages) {
 			ret = -EINVAL;
 			goto unlock;
 		}
diff --git a/kernel/events/internal.h b/kernel/events/internal.h
index 8fc0ddc38cb69edde47332b9afdefc2ba4e4cf23..578de8c2694bcdec447a2facc0be7ff87193d9a8 100644
--- a/kernel/events/internal.h
+++ b/kernel/events/internal.h
@@ -114,6 +114,11 @@ static inline int page_order(struct ring_buffer *rb)
 }
 #endif
 
+static inline int data_page_nr(struct ring_buffer *rb)
+{
+	return rb->nr_pages << page_order(rb);
+}
+
 static inline unsigned long perf_data_size(struct ring_buffer *rb)
 {
 	return rb->nr_pages << (PAGE_SHIFT + page_order(rb));
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index 34e1667e4254979c71821fc64fc0a928f5654cd2..a69378d901faf5ed2a9783f97f84aa869856d878 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -803,10 +803,6 @@ void rb_free(struct ring_buffer *rb)
 }
 
 #else
-static int data_page_nr(struct ring_buffer *rb)
-{
-	return rb->nr_pages << page_order(rb);
-}
 
 static struct page *
 __perf_mmap_to_page(struct ring_buffer *rb, unsigned long pgoff)