Re: [net-next][PATCH v2 18/18] RDS: IB: add missing connection cache usage info

From: Santosh Shilimkar
Date: Wed Dec 07 2016 - 15:41:59 EST


On 12/7/2016 9:36 AM, David Miller wrote:

[...]

What does the newer tool do on an older kernel if it doesn't see
the fields? Does it check the size of the structure given back
to it, and conditionally handle the older vs. the newer layout?

It must do this.

Right but the rds-tool doesn't handle it well and needs
to be fixed before this or any additional change in rds-info
structures. To handle the kernel struct size issues with its
user copy, there is a provision to probe kernel struct len
and then decide on layout buts its not used/implemented
in tools. The parsing comment I made is also not completely
accurate.

For now, I will drop this patch and submit it once the tools
code is fixed along with other used fields to handle both
layouts.

I should have checked the full compatibility matrix as you
commented. Sorry for oversight. Thanks for your comments Dave.

Regard,
Santosh