On Tue, Nov 13, 2018 at 03:35:20PM +0100, Benjamin Block wrote: > This seems like a non-obvious user-breakage. So apart from removing the > in-kernel stuff that uses bidirectional commands you also forbid > userspace from every using them? That seems wrong to me. > > There is other SCSI Command Sets than OSD that provide bidirectional > commands, even SBC has some (i.e. X*WRITE*, COMPARE AND WRITE). Yes, there are a few. But the only driver that even supports them right now is iscsi_tcp to start with, and we have to drag a significant amount of code around just to support this corner case.