On Mon, 1 Jul 2019, Oliver Neukum wrote: > Am Mittwoch, den 26.06.2019, 10:38 -0400 schrieb Alan Stern: > > On Wed, 26 Jun 2019, Oliver Neukum wrote: > > > > > Am Montag, den 24.06.2019, 10:22 -0400 schrieb Alan Stern: > > > > But that pattern makes no sense; a driver would never use it. The > > > > driver would just do the reset itself. > > > > > > Correct. But UAS and storage themselves still need to use > > > WQ_MEM_RECLAIM for their workqueues, don't they? > > > > Perhaps so for uas. usb-storage uses a work queue only for scanning > > targets, which doesn't interfere with the block I/O pathway. > > Are you sure? What about hub_tt_work? Technically speaking, hub_tt_work is used by the hub driver, not by usb-storage. :-) > As far as I can tell, hub_quiesce > will flush it, hence it is used in error handling. Yes, it needs to use a work queue with WQ_MEM_RECLAIM set. Unfortunately, I don't think we can use hub_wq for this purpose (we could end up with a work item waiting for another work item later on in the same queue, not good). Alan Stern
