[PATCH] nvme: Use non zero KATO for persistent discovery connections

[Martin George]

On Tue, 2025-09-02 at 13:52 +1000, alistair23 at gmail.com wrote:
> From: Alistair Francis <alistair.francis at wdc.com>
> 
> The NVMe Base Specification 2.1 states that:
> 
> """
> A host requests an explicit persistent connection ... by specifying a
> non-zero Keep Alive Timer value in the Connect command.
> """
> 
> As such if we are starting a persistent connection to a discovery
> controller and the KATO is currently 0 we need to update KATO to a
> non
> zero value to avoid continuous timeouts on the target.
> 
> 

When would this ever happen? Won't nvme-cli & nvme/host/fabrics.c in
the kernel ensure a PDC (persistent discovery controller) would always
have the KATO either default set to NVMF_DEF_DISC_TMO (i.e. 30s) or any
positive int value & not zero?

Do you have a test log for the above scenario where the KATO ends up
being zero for a PDC?

-Martin