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Date: Sat, 6 Apr 2024 17:03:54 +0100
From: Simon Horman <horms@kernel.org>
To: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Cc: Jay Vosburgh <j.vosburgh@gmail.com>,
	Andy Gospodarek <andy@greyhouse.net>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net] bonding: 802.3ad: Avoid packet loss when switching
 aggregator
Message-ID: <20240406160354.GW26556@kernel.org>
References: <20240404114908.134034-1-tbogendoerfer@suse.de>
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In-Reply-To: <20240404114908.134034-1-tbogendoerfer@suse.de>

On Thu, Apr 04, 2024 at 01:49:08PM +0200, Thomas Bogendoerfer wrote:
> If selection logic decides to switch to a new aggregator it disables
> all ports of the old aggregator, but doesn't enable ports on
> the new aggregator. These ports will eventually be enabled when
> the next LACPDU is received, which might take some time and without an
> active port transmitted frames are dropped. Avoid this by enabling
> already collected ports of the new aggregator immediately.
> 
> Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>

Hi Thomas,

I will leave the technical review to Jay and others.  But as a fix, I think
this patch warrants a Fixes tag. It should be sufficient to respond to this
email thread with an appropriate tag.

> ---
>  drivers/net/bonding/bond_3ad.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c
> index c6807e473ab7..529e2a7c51e2 100644
> --- a/drivers/net/bonding/bond_3ad.c
> +++ b/drivers/net/bonding/bond_3ad.c
> @@ -1876,6 +1876,13 @@ static void ad_agg_selection_logic(struct aggregator *agg,
>  				__disable_port(port);
>  			}
>  		}
> +
> +		/* enable ports on new active aggregator */
> +		for (port = best->lag_ports; port;
> +			port = port->next_port_in_aggregator) {
> +			__enable_port(port);
> +		}
> +
>  		/* Slave array needs update. */
>  		*update_slave_arr = true;
>  	}
> -- 
> 2.35.3
> 
>