On 02/17/2017 09:55 AM, Christoph Hellwig wrote: > On Fri, Feb 17, 2017 at 09:23:09AM +0100, Hannes Reinecke wrote: >> The block layer already has the notion of 'reserved' commands, so >> we should be enabling hosts to allocate them. > > How does this interact with the non blk-mq path? > It doesn't; legacy sq doesn't have the notion of 'reserved' command. So here's my question: how are 'reserved' commands are imagined to be used? ATM they exist for blk-mq solely, and are not even implemented for legacy sq. At the same time quite some drivers (like mpt3sas) really could make use of the notion of 'reserved' commands. Does it make sense to implement 'reserved' commands for the legacy sq code path, too? I'd be happy to implement something like this; would make life far easier in certain other places, too (fnic springs to mind ...) Bug if so, would such a patch being accepted? Any attempts to modify legacy sq has been met with heavy resistance so far ... Cheers, Hannes -- Dr. Hannes Reinecke Teamlead Storage & Networking hare@xxxxxxx +49 911 74053 688 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton HRB 21284 (AG Nürnberg)
