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Date: Wed, 8 May 2024 11:14:46 +0100
From: Simon Horman <horms@kernel.org>
To: Lukasz Majewski <lukma@denx.de>
Cc: Jakub Kicinski <kuba@kernel.org>, netdev@vger.kernel.org,
	Paolo Abeni <pabeni@redhat.com>, Eric Dumazet <edumazet@google.com>,
	Vladimir Oltean <olteanv@gmail.com>,
	"David S. Miller" <davem@davemloft.net>,
	Oleksij Rempel <o.rempel@pengutronix.de>, Tristram.Ha@microchip.com,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Ravi Gunasekaran <r-gunasekaran@ti.com>,
	Nikita Zhandarovich <n.zhandarovich@fintech.ru>,
	Murali Karicheri <m-karicheri2@ti.com>,
	Arvid Brodin <Arvid.Brodin@xdin.com>,
	Dan Carpenter <dan.carpenter@linaro.org>,
	"Ricardo B. Marliere" <ricardo@marliere.net>,
	Casper Andersson <casper.casan@gmail.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [net PATCH v2] hsr: Simplify code for announcing HSR nodes timer
 setup
Message-ID: <20240508101446.GC1736038@kernel.org>
References: <20240507111214.3519800-1-lukma@denx.de>
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In-Reply-To: <20240507111214.3519800-1-lukma@denx.de>

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@denx.de>
> 
> 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@kernel.org>