Re: [net PATCH v2] hsr: Simplify code for announcing HSR nodes timer setup

[Simon Horman]

On Tue, May 07, 2024 at 01:12:14PM +0200, Lukasz Majewski wrote:
> Up till now the code to start HSR announce timer, which triggers sending
> supervisory frames, was assuming that hsr_netdev_notify() would be called
> at least twice for hsrX interface. This was required to have different
> values for old and current values of network device's operstate.
> 
> This is problematic for a case where hsrX interface is already in the
> operational state when hsr_netdev_notify() is called, so timer is not
> configured to trigger and as a result the hsrX is not sending supervisory
> frames to HSR ring.
> 
> This error has been discovered when hsr_ping.sh script was run. To be
> more specific - for the hsr1 and hsr2 the hsr_netdev_notify() was
> called at least twice with different IF_OPER_{LOWERDOWN|DOWN|UP} states
> assigned in hsr_check_carrier_and_operstate(hsr). As a result there was
> no issue with sending supervisory frames.
> However, with hsr3, the notify function was called only once with
> operstate set to IF_OPER_UP and timer responsible for triggering
> supervisory frames was not fired.
> 
> The solution is to use netif_oper_up() and netif_running() helper
> functions to assess if network hsrX device is up.
> Only then, when the timer is not already pending, it is started.
> Otherwise it is deactivated.
> 
> Signed-off-by: Lukasz Majewski <lukma@xxxxxxx>
> 
> Fixes: f421436a591d ("net/hsr: Add support for the High-availability Seamless Redundancy protocol (HSRv0)")
> ---
> Changes for v2:
> 
> - Add extra condition to check if the hsr network device is running
>   (not only up).
> 
> - Only start announce timer when it is not pending (to avoid period
>   shortening/violation)

Reviewed-by: Simon Horman <horms@xxxxxxxxxx>