[PATCH v6 17/18] nvme: Add support for CQT to nvme host

[Daniel Wagner]

On Sun, Sep 20, 2026 at 11:28:15AM -0700, Mohamed Khalfella wrote:
> TP4129 KATO Corrections and Clarifications defined CQT (Command Quiesce
> Time) which is used along with KATO (Keep Alive Timeout) to set an upper
> limit for attempting Cross-Controller Recovery. Add ctrl->cqt, read its
> value from controller identify response, expose it via sysfs, and have
> nvme_fence_timeout_ms() account for it.
> 
> Use CQT to drive time-based recovery in fc, rdma, and tcp transports.
> Add a fenced_work delayed work to each transport controller. If CCR
> fails, fencing_work switches to error recovery immediately if CQT is not
> supported. Otherwise it schedules fenced_work after the remaining fence
> timeout, which also switches to error recovery when scheduled.
> 
> Signed-off-by: Mohamed Khalfella <mkhalfella at purestorage.com>
> Reviewed-by: Hannes Reinecke <hare at kernel.org>
> Reviewed-by: Sagi Grimberg <sagi at grimberg.me>

the sysfs entry needs to be documented, with this

Reviewed-by: Daniel Wagner <dwagner at suse.de>