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Date: Thu, 8 Aug 2024 08:10:54 -0700
From: Jakub Kicinski <kuba@kernel.org>
To: Jamie Bainbridge <jamie.bainbridge@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>, Eric Dumazet
 <edumazet@google.com>, Paolo Abeni <pabeni@redhat.com>, Johannes Berg
 <johannes@sipsolutions.net>, Shigeru Yoshida <syoshida@redhat.com>, Simon
 Horman <horms@kernel.org>, netdev@vger.kernel.org,
 linux-kernel@vger.kernel.org
Subject: Re: [PATCH net v4] net-sysfs: check device is present when showing
 duplex
Message-ID: <20240808081054.1291238d@kernel.org>
In-Reply-To: <6c6b2fecaf381b25ec8d5ecc4e30ff2a186cad48.1722925756.git.jamie.bainbridge@gmail.com>
References: <6c6b2fecaf381b25ec8d5ecc4e30ff2a186cad48.1722925756.git.jamie.bainbridge@gmail.com>
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On Tue,  6 Aug 2024 16:35:27 +1000 Jamie Bainbridge wrote:
> A sysfs reader can race with a device reset or removal, attempting to
> read device state when the device is not actually present.

True, but..

> -	if (netif_running(netdev)) {
> +	if (netif_running(netdev) && netif_device_present(netdev)) {
>  		struct ethtool_link_ksettings cmd;
>  
>  		if (!__ethtool_get_link_ksettings(netdev, &cmd)) {

..there are more callers of __ethtool_get_link_ksettings() and only 
a fraction of them have something resembling a presence check in
their path. Can we put the check inside __ethtool_get_link_ksettings()
itself?