Re: [PATCH 6/8] bsg-lib: handle bidi requests without block layer help

[Christoph Hellwig]

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.