diff --git a/[refs] b/[refs]
index b73e6a76f627..5c4e2eacbc7e 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 3ffab428f40849ed5f21bcfd7285bdef7902f9ca
+refs/heads/master: df30b21cb0eed5ba8a8e0cdfeebc66ba8cde821d
diff --git a/trunk/drivers/staging/comedi/comedi_fops.c b/trunk/drivers/staging/comedi/comedi_fops.c
index 156622a6f162..88caa7376999 100644
--- a/trunk/drivers/staging/comedi/comedi_fops.c
+++ b/trunk/drivers/staging/comedi/comedi_fops.c
@@ -1432,7 +1432,21 @@ static int do_cancel(struct comedi_device *dev, struct comedi_subdevice *s)
 	return ret;
 }
 
-static void comedi_unmap(struct vm_area_struct *area)
+
+static void comedi_vm_open(struct vm_area_struct *area)
+{
+	struct comedi_async *async;
+	struct comedi_device *dev;
+
+	async = area->vm_private_data;
+	dev = async->subdevice->device;
+
+	mutex_lock(&dev->mutex);
+	async->mmap_count++;
+	mutex_unlock(&dev->mutex);
+}
+
+static void comedi_vm_close(struct vm_area_struct *area)
 {
 	struct comedi_async *async;
 	struct comedi_device *dev;
@@ -1446,7 +1460,8 @@ static void comedi_unmap(struct vm_area_struct *area)
 }
 
 static struct vm_operations_struct comedi_vm_ops = {
-	.close = comedi_unmap,
+	.open = comedi_vm_open,
+	.close = comedi_vm_close,
 };
 
 static int comedi_mmap(struct file *file, struct vm_area_struct *vma)