[rds-devel] [PATCH RFC v1] Feature reporting of RDS driver.

[Allison Henderson]

On Tue, 2025-06-10 at 12:27 -0400, Konrad Rzeszutek Wilk wrote:
> Hi folks,
> 
> This patch addresses an issue where we have applications compiled against
> against older (or newer) kernels. RDS does not have any ioctls to query
> for what version of ABIs it has or what features it has. Hence this solution
> that proposes to put this ABI information in user-accessible way.
> 
> The patch does it two ways:
> 
> 1) Power of the ELF .note section to put in the module so that
> applications can discern before installing whether the kernel
> has the right support.
> 
> 2) The sysfs way - in which the /sys/modules/ was appealing since
> it was simple and non invasive means of delivering this functionality,
> and requires no changes to existing APIs or kernel logic.
> 
> I am not tied to any specific ways - hence the request for collaboration.
> 
> And as such questions, comments and discussion are appreciated and if you
> have read to this part - then thank you for spending your time reading over
> this cover letter and I am looking forward to your feedback on the patch!
> 
> Konrad Rzeszutek Wilk (1):
>       rds: Expose feature parameters via sysfs and ELF note

Hi Konrad,

Thanks for the rfc,  I think this is a great way to start discussion for exploring solutions and collecting opinions. 
The elfnotes are creative, but I think the module parameters is more commonly seen.  Andrew makes a good point that
these are not actually module parameters though, so I think the feature search suggestion is worth exploring.  I'll do
some digging on existing patterns too, as I am not sure the best practice myself.  

Thanks again for getting this started!

Allison


> 
>  Documentation/ABI/stable/sysfs-driver-rds | 92 +++++++++++++++++++++++++++++++
>  net/rds/af_rds.c                          | 33 +++++++++++
>  2 files changed, 125 insertions(+)