[dm-devel] reinstate dm target local ioctl support

[Andy Whitcroft]

On Fri, Jan 29, 2016 at 01:57:12PM +0000, Alasdair G Kergon wrote:
> On Thu, Jan 28, 2016 at 01:50:19PM +0000, Andy Whitcroft wrote:
> > However this also removed the possibility of a dm target having target
> > specific ioctls.  Currently this is not used by any in-tree targets but
> > was utilised by the flashcache out-of-tree module.
>  
> What data is being passed in and out?
> 
> The method we support is passing it through DM_TARGET_MSG (as text).
> For examples look at dm-switch.c and dm-stats.c, which handled
> pretty large quantities of data.
> 
> Would that work?

That sounds like it has all the bits one would need indeed.  I will
investigate that.  Thanks for the info.

-apw