Re: reinstate dm target local ioctl support

From	Andy Whitcroft <apw@canonical.com>
Newsgroups	linux.kernel
Subject	Re: reinstate dm target local ioctl support
Date	2016-01-29 15:40 +0100
Message-ID	<qWinp-4u4-37@gated-at.bofh.it> (permalink)
References	<qVVh8-4b8-15@gated-at.bofh.it> <qWhKG-3Ue-7@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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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

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reinstate dm target local ioctl support Andy Whitcroft <apw@canonical.com> - 2016-01-28 15:00 +0100
  Re: reinstate dm target local ioctl support Christoph Hellwig <hch@lst.de> - 2016-01-28 15:10 +0100
  Re: [dm-devel] reinstate dm target local ioctl support Joe Thornber <thornber@redhat.com> - 2016-01-29 15:00 +0100
  Re: reinstate dm target local ioctl support Alasdair G Kergon <agk@redhat.com> - 2016-01-29 15:00 +0100
    Re: reinstate dm target local ioctl support Andy Whitcroft <apw@canonical.com> - 2016-01-29 15:40 +0100

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