[Accel-config] Re: [PATCH] accel-config: Replicate driver error codes in idxd.h in library

Noticed driver idxd.h has GPL license. Library is LGPL and I remember
LGPL cannot use GPL code. Even if that is changed in newer drivers I am
not sure if there is any issue with older drivers.

On Mon, Jul 19, 2021 at 01:00:46PM -0700, Dave Jiang wrote:
> 
> On 7/19/2021 12:35 PM, Thomas, Ramesh wrote:
> > On Mon, Jul 19, 2021 at 10:50:09AM -0700, Dave Jiang wrote:
> >> On 7/19/2021 10:34 AM, Thomas, Ramesh wrote:
> >>> I think copying will have the problem of compiler picking different
> >>> ones. Library may use the copied version while the app may get the one
> >>> in /usr/include. Do you think defining new constants would be safer?
> >> I think instead of pulling the /usr/include version we just depend on
> >> the copied version exclusively. Then we will have 1 less dependency and
> >> compile correctly always.
> > I was also concerned about user apps including the /user/include idxd.h.
> > Even in libaccel we would need to make assumptions that the constants
> > used will not diverge from the one driver is using. Since the issue is
> > only about some constants like the sw cmd_status which is not available
> > in older idxd.h, I think it is better to define them separately and
> > privately for the library.
> >
> User ABI is considered constant for Linux and if we are changing it,
> there would be ways to provide backward compatibility. I think making
> copy of header should be safe. That is why ndctl does that.
> >