linux-kernel - Re: [PATCH net V2] net: bridge: br_fdb_external_learn_add(): always set EXT

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Message-ID: <ZtcVmsqk0m1S-XuQ@shredder.mtl.com>
Date: Tue, 3 Sep 2024 16:56:42 +0300
From: Ido Schimmel <idosch@...dia.com>
To: Jonas Gorski <jonas.gorski@...dn.de>
Cc: Roopa Prabhu <roopa@...dia.com>,
	Nikolay Aleksandrov <razor@...ckwall.org>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Ido Schimmel <idosch@...lanox.com>,
	Petr Machata <petrm@...lanox.com>, bridge@...ts.linux.dev,
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH net V2] net: bridge: br_fdb_external_learn_add(): always
 set EXT_LEARN

On Tue, Sep 03, 2024 at 10:19:57AM +0200, Jonas Gorski wrote:
> When userspace wants to take over a fdb entry by setting it as
> EXTERN_LEARNED, we set both flags BR_FDB_ADDED_BY_EXT_LEARN and
> BR_FDB_ADDED_BY_USER in br_fdb_external_learn_add().
> 
> If the bridge updates the entry later because its port changed, we clear
> the BR_FDB_ADDED_BY_EXT_LEARN flag, but leave the BR_FDB_ADDED_BY_USER
> flag set.
> 
> If userspace then wants to take over the entry again,
> br_fdb_external_learn_add() sees that BR_FDB_ADDED_BY_USER and skips
> setting the BR_FDB_ADDED_BY_EXT_LEARN flags, thus silently ignores the
> update.
> 
> Fix this by always allowing to set BR_FDB_ADDED_BY_EXT_LEARN regardless
> if this was a user fdb entry or not.
> 
> Fixes: 710ae7287737 ("net: bridge: Mark FDB entries that were added by user as such")
> Signed-off-by: Jonas Gorski <jonas.gorski@...dn.de>

Reviewed-by: Ido Schimmel <idosch@...dia.com>