On Tue, Feb 26, 2019 at 02:49:30PM +0100, Hannes Reinecke wrote: > Attached is a patch to demonstrate my approach. > I am aware that it'll only be useful for latest upstream where the legacy > I/O path has been dropped completely, so we wouldn't need to worry about it. > For older releases indeed you would need to with something like your > proposed patch, but for upstream I really would like to switch to > blk_mq_tagset_busy() iter. While this is better than the driver private tracking we really should not have to iterate all outstanding command, because if we have any there is a bug we need to fix in the higher layers instead of working around it in the drivers.