block: add and use scsi_blk_cmd_ioctl

Introduce a wrapper around scsi_cmd_ioctl that takes a block device.

The function will then be enhanced to detect partition block devices
and, in that case, subject the ioctls to whitelisting.

Cc: linux-scsi@vger.kernel.org
Cc: Jens Axboe <axboe@kernel.dk>
Cc: James Bottomley <JBottomley@parallels.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 7b3f807..b4d57bb 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1097,7 +1097,7 @@
 			error = scsi_ioctl(sdp, cmd, p);
 			break;
 		default:
-			error = scsi_cmd_ioctl(disk->queue, disk, mode, cmd, p);
+			error = scsi_cmd_blk_ioctl(bdev, mode, cmd, p);
 			if (error != -ENOTTY)
 				break;
 			error = scsi_ioctl(sdp, cmd, p);