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Date: Tue, 5 Dec 2023 16:11:03 -0800
From: Jakub Kicinski <kuba@kernel.org>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: netdev@vger.kernel.org, Johannes Berg <johannes.berg@intel.com>
Subject: Re: [PATCH net] net: core: synchronize link-watch when carrier is
 queried
Message-ID: <20231205161103.3bec2036@kernel.org>
In-Reply-To: <20231204214706.303c62768415.I1caedccae72ee5a45c9085c5eb49c145ce1c0dd5@changeid>
References: <20231204214706.303c62768415.I1caedccae72ee5a45c9085c5eb49c145ce1c0dd5@changeid>
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On Mon,  4 Dec 2023 21:47:07 +0100 Johannes Berg wrote:
> There are multiple ways to query for the carrier state: through
> rtnetlink, sysfs, and (possibly) ethtool. Synchronize linkwatch
> work before these operations so that we don't have a situation
> where userspace queries the carrier state between the driver's
> carrier off->on transition and linkwatch running and expects it
> to work, when really (at least) TX cannot work until linkwatch
> has run.
> 
> I previously posted a longer explanation of how this applies to
> wireless [1] but with this wireless can simply query the state
> before sending data, to ensure the kernel is ready for it.

Are you okay with net-next?
The previous behavior is, herm... well established.