Re: [RFC][PATCH] nbd driver for 2.5+: fix locking issues with ioctl UI

[Christoph Hellwig]

On Wed, Jun 25, 2003 at 09:36:50AM -0600, Lou Langholtz wrote:
> I have also attached a patch to Pavel's nbd-2.0 release nbd tools that 
> updates the nbd-client to work with linux 2.5 as well as 2.5.74 
> (assuming the aforementioned patch 6.1 made it into 2.5.74). Handling is 
> switched at compile time however and uses <linux/version.h> to do the 
> switching. This will have problems of course if the builder doesn't pay 
> close attention to where there header file are coming from or tries to 
> run the same binary on a different kernel release. Etc.

That's broken.  You must make sure that a binary works with different
kernels or at least make it fail gracefully.  Using <linux/version.h>
from userspace is absolutely not acceptable, just don't use kernel headers
at all but a local copy of <linux/nbd.h>.