Re: [PATCH net 3/6] igc: Handle already enabled taprio offload for basetime 0

[Leon Romanovsky <leon@kernel.org>]

On Mon, Jul 10, 2023 at 09:35:00AM -0700, Tony Nguyen wrote:
> From: Florian Kauer <florian.kauer@linutronix.de>
> 
> Since commit e17090eb2494 ("igc: allow BaseTime 0 enrollment for Qbv")
> it is possible to enable taprio offload with a basetime of 0.
> However, the check if taprio offload is already enabled (and thus -EALREADY
> should be returned for igc_save_qbv_schedule) still relied on
> adapter->base_time > 0.
> 
> This can be reproduced as follows:
> 
>     # TAPRIO offload (flags == 0x2) and base-time = 0
>     sudo tc qdisc replace dev enp1s0 parent root handle 100 stab overhead 24 taprio \
> 	    num_tc 1 \
> 	    map 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 \
> 	    queues 1@0 \
> 	    base-time 0 \
> 	    sched-entry S 01 300000 \
> 	    flags 0x2
> 
>     # The second call should fail with "Error: Device failed to setup taprio offload."
>     # But that only happens if base-time was != 0
>     sudo tc qdisc replace dev enp1s0 parent root handle 100 stab overhead 24 taprio \
> 	    num_tc 1 \
> 	    map 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 \
> 	    queues 1@0 \
> 	    base-time 0 \
> 	    sched-entry S 01 300000 \
> 	    flags 0x2
> 
> Fixes: e17090eb2494 ("igc: allow BaseTime 0 enrollment for Qbv")
> Signed-off-by: Florian Kauer <florian.kauer@linutronix.de>
> Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de>
> Tested-by: Naama Meir <naamax.meir@linux.intel.com>
> Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
> ---
>  drivers/net/ethernet/intel/igc/igc_main.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 

Thanks,
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>