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Date:   Thu, 24 Feb 2022 07:56:18 +0000
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Subject: Re: [PATCH v2 2/2] Revert "xen-netback: Check for hotplug-status
 existence before watching"
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        <marmarek@invisiblethingslab.com>, linux-kernel@vger.kernel.org
Cc:     stable@vger.kernel.org, Michael Brown <mcb30@ipxe.org>,
        Wei Liu <wei.liu@kernel.org>, Paul Durrant <paul@xen.org>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        "moderated list:XEN NETWORK BACKEND DRIVER" 
        <xen-devel@lists.xenproject.org>,
        "open list:XEN NETWORK BACKEND DRIVER" <netdev@vger.kernel.org>
References: <20220222001817.2264967-1-marmarek@invisiblethingslab.com>
 <20220222001817.2264967-2-marmarek@invisiblethingslab.com>
From:   "Durrant, Paul" <xadimgnik@gmail.com>
In-Reply-To: <20220222001817.2264967-2-marmarek@invisiblethingslab.com>
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On 22/02/2022 00:18, Marek Marczykowski-Górecki wrote:
> This reverts commit 2afeec08ab5c86ae21952151f726bfe184f6b23d.
> 
> The reasoning in the commit was wrong - the code expected to setup the
> watch even if 'hotplug-status' didn't exist. In fact, it relied on the
> watch being fired the first time - to check if maybe 'hotplug-status' is
> already set to 'connected'. Not registering a watch for non-existing
> path (which is the case if hotplug script hasn't been executed yet),
> made the backend not waiting for the hotplug script to execute. This in
> turns, made the netfront think the interface is fully operational, while
> in fact it was not (the vif interface on xen-netback side might not be
> configured yet).
> 
> This was a workaround for 'hotplug-status' erroneously being removed.
> But since that is reverted now, the workaround is not necessary either.
> 
> More discussion at
> https://lore.kernel.org/xen-devel/afedd7cb-a291-e773-8b0d-4db9b291fa98@ipxe.org/T/#u
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>

Reviewed-by: Paul Durrant <paul@xen.org>