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>

drivers/ide/ide-floppy_ioctl.c

@@ -292,8 +292,7 @@ int ide_floppy_ioctl(ide_drive_t *drive, struct block_device *bdev,
 	 * and CDROM_SEND_PACKET (legacy) ioctls
 	 */
 	if (cmd != CDROM_SEND_PACKET && cmd != SCSI_IOCTL_SEND_COMMAND)
-		err = scsi_cmd_ioctl(bdev->bd_disk->queue, bdev->bd_disk,
-				mode, cmd, argp);
+		err = scsi_cmd_blk_ioctl(bdev, mode, cmd, argp);
 
 	if (err == -ENOTTY)
 		err = generic_ide_ioctl(drive, bdev, cmd, arg);