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

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.
>