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Date:   Mon, 7 Sep 2020 21:10:13 -0700
From:   Jakub Kicinski <kuba@kernel.org>
To:     Dexuan Cui <decui@microsoft.com>
Cc:     wei.liu@kernel.org, kys@microsoft.com, haiyangz@microsoft.com,
        sthemmin@microsoft.com, davem@davemloft.net,
        linux-hyperv@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, mikelley@microsoft.com
Subject: Re: [PATCH net v2] hv_netvsc: Fix hibernation for mlx5 VF driver
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On Mon,  7 Sep 2020 00:13:39 -0700 Dexuan Cui wrote:
> mlx5_suspend()/resume() keep the network interface, so during hibernation
> netvsc_unregister_vf() and netvsc_register_vf() are not called, and hence
> netvsc_resume() should call netvsc_vf_changed() to switch the data path
> back to the VF after hibernation. Note: after we close and re-open the
> vmbus channel of the netvsc NIC in netvsc_suspend() and netvsc_resume(),
> the data path is implicitly switched to the netvsc NIC. Similarly,
> netvsc_suspend() should not call netvsc_unregister_vf(), otherwise the VF
> can no longer be used after hibernation.
> 
> For mlx4, since the VF network interafce is explicitly destroyed and
> re-created during hibernation (see mlx4_suspend()/resume()), hv_netvsc
> already explicitly switches the data path from and to the VF automatically
> via netvsc_register_vf() and netvsc_unregister_vf(), so mlx4 doesn't need
> this fix. Note: mlx4 can still work with the fix because in
> netvsc_suspend()/resume() ndev_ctx->vf_netdev is NULL for mlx4.
> 
> Fixes: 0efeea5fb153 ("hv_netvsc: Add the support of hibernation")
> Signed-off-by: Dexuan Cui <decui@microsoft.com>

Applied, thanks!