[ewg] Question about CONFIG_COMPAT_RHEL_6_4

[Vladimir Sokolovsky]

----- Original Message -----
> From: "Shuichi Ihara" <sihara at ddn.com>
> To: ewg at lists.openfabrics.org
> Sent: Monday, May 27, 2013 2:47:49 PM
> Subject: [ewg] Question about CONFIG_COMPAT_RHEL_6_4
> 
> 
> Hi,
> 
> I'm testing lustre with OFED-3.5.1 against RHEL6.4 kernel.
> There are a lot of duplicated functions and macro name in the compat
> headers that there are already defined in RHEL6.4's kernel as their
> own backport.
> However, this is fine. In order to ignore them, I see there is
> special macro CONFIG_COMPAT_RHEL_6_4.
> Thanks for this superset for RHEL6.4 kernel!
> 
> I have succeeded Lustre build with "-DCONFIG_COMPAT_RHEL_6_4".
> 
> However, in general (not only lustre, but also building kernel module
> with OFED-3.x against RHEL kernel) I'm wondering what is proper
> process if we want to build with OFED and RHEL kernel.
> 
> And, here is my additional questions...
> 
> 1. OFED-3.x is NO auto detection kernel version and set superset
> macro (like CONFIG_COMPAT_RHEL_6_4) in OFED itself?
> Does user have to make sure kernel version and set
> -DCONFIG_COMPAT_RHEL_6_4 to build?

Currently, in OFED-3.5*, this is the only way to compile kernel module with OFED.
I plan to add dynamic construction of the compat.mk by parsing kernel headers to avoid using "CONFIG_COMPAT_RHEL_6_4" like macros.

> 
> 2. What happen if new new distribution update release out? We will
> see CONFIG_COMPAT_RHEL_6_{5,6}??

It depends if I will accomplish dynamic construction of the compat.mk by then.

> 
> 3. How about other distribution case? Any development documentation
> available for OFED-3.x?
> 

> Thanks
> Ihara
> 

For other distributions need to define the corresponding macro or create a set of CFLAGS that will fit the kernel API.
Currently, there is no relevant documentation available. I hope it will be ready by the next OFED release.

Regards,
Vladimir