[media] Revert "V4L/DVB: v4l2-dev: remove get_unmapped_area"

This reverts commit c29fcff3daafbf46d64a543c1950bbd206ad8c1c.

Signed-off-by: Bob Liu <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/video/v4l2-dev.c

···
 	return ret;
 }
 
+#ifdef CONFIG_MMU
+#define v4l2_get_unmapped_area NULL
+#else
+static unsigned long v4l2_get_unmapped_area(struct file *filp,
+		unsigned long addr, unsigned long len, unsigned long pgoff,
+		unsigned long flags)
+{
+	struct video_device *vdev = video_devdata(filp);
+
+	if (!vdev->fops->get_unmapped_area)
+		return -ENOSYS;
+	if (!video_is_registered(vdev))
+		return -ENODEV;
+	return vdev->fops->get_unmapped_area(filp, addr, len, pgoff, flags);
+}
+#endif
+
 static int v4l2_mmap(struct file *filp, struct vm_area_struct *vm)
 {
 	struct video_device *vdev = video_devdata(filp);
···
 	.read = v4l2_read,
 	.write = v4l2_write,
 	.open = v4l2_open,
+	.get_unmapped_area = v4l2_get_unmapped_area,
 	.mmap = v4l2_mmap,
 	.unlocked_ioctl = v4l2_ioctl,
 #ifdef CONFIG_COMPAT

include/media/v4l2-dev.h

···
 	unsigned int (*poll) (struct file *, struct poll_table_struct *);
 	long (*ioctl) (struct file *, unsigned int, unsigned long);
 	long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
+	unsigned long (*get_unmapped_area) (struct file *, unsigned long,
+				unsigned long, unsigned long, unsigned long);
 	int (*mmap) (struct file *, struct vm_area_struct *);
 	int (*open) (struct file *);
 	int (*release) (struct file *);