On Wed, Jan 11, 2017 at 05:01:22PM -0500, Mike Snitzer wrote: > But I've seen you reference the need to stop multipath from allocating > its own requests. Are you referring to old request_fn request-based > multipath's clone_old_rq:alloc_old_clone_request?
Yes, that one is the issue. It allocates a struct request "blind", that is without known what queue it goes to. With this queue (or blk-mq for that matter) we need to know the queue, because the request structures might have additional data behind it and require additional initialization for drivers that require per-request data. We make use of the per-request data for SCSI passthrough in this patch. > Or how blk-mq request-based multipath gets a request from the blk-mq tag > space (via blk_mq_alloc_request)? That's fine because it works on the queue of the device that I/O is submitted to. -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
