diff --git a/kernel/events/core.c b/kernel/events/core.c
index 23bb19716ad3..7858bafffa9d 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6247,7 +6247,7 @@ 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 082832738c8f..5150d5f84c03 100644
--- a/kernel/events/internal.h
+++ b/kernel/events/internal.h
@@ -116,6 +116,11 @@ static inline int page_order(struct perf_buffer *rb)
 }
 #endif
 
+static inline int data_page_nr(struct perf_buffer *rb)
+{
+	return rb->nr_pages << page_order(rb);
+}
+
 static inline unsigned long perf_data_size(struct perf_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 52868716ec35..fb35b926024c 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -859,11 +859,6 @@ void rb_free(struct perf_buffer *rb)
 }
 
 #else
-static int data_page_nr(struct perf_buffer *rb)
-{
-	return rb->nr_pages << page_order(rb);
-}
-
 static struct page *
 __perf_mmap_to_page(struct perf_buffer *rb, unsigned long pgoff)
 {