compat_ioctl: ubd, aoe: use blkdev_compat_ptr_ioctl

These drivers implement the HDIO_GET_IDENTITY and CDROMVOLREAD ioctl
commands, which are compatible between 32-bit and 64-bit user space and
traditionally handled by compat_blkdev_driver_ioctl().

As a prerequisite to removing that function, make both drivers use
blkdev_compat_ptr_ioctl() as their .compat_ioctl callback.
Reviewed-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/um/drivers/ubd_kern.c

@@ -113,6 +113,7 @@ static const struct block_device_operations ubd_blops = {
         .open		= ubd_open,
         .release	= ubd_release,
         .ioctl		= ubd_ioctl,
+        .compat_ioctl	= blkdev_compat_ptr_ioctl,
 	.getgeo		= ubd_getgeo,
 };
 

drivers/block/aoe/aoeblk.c

@@ -329,6 +329,7 @@ static const struct block_device_operations aoe_bdops = {
 	.open = aoeblk_open,
 	.release = aoeblk_release,
 	.ioctl = aoeblk_ioctl,
+	.compat_ioctl = blkdev_compat_ptr_ioctl,
 	.getgeo = aoeblk_getgeo,
 	.owner = THIS_MODULE,
 };