On 04/19/2017 10:54 PM, Christoph Hellwig wrote: > On Thu, Apr 20, 2017 at 09:03:47AM +0800, Ming Lei wrote: >> If we don't need to reserve tag for internal command, I am happy >> to fix it in the interim. However, the mtip32xx driver has to >> ask blk-mq to reserve the tag zero for internal command. Then >> if we can't allow the driver to use that reserved tag, it looks >> quite awkward, doesn't it? > > It doesn't. Just offset the hardware tags by 1 from the blk-mq tags. > > But I'm pretty sure the hardware wouldn't require a specific tag > for the internal ops. Right, the hardware doesn't require it at all, it's just an oddity of the driver that it hardwares tag 0 as an internal tag. That could definitely get cleaned up. -- Jens Axboe