RE: [PATCH][PATCH net-next] hv_netvsc: Add the support of hibernation

[Haiyang Zhang <haiyangz@microsoft.com>]

> -----Original Message-----
> From: Dexuan Cui <decui@microsoft.com>
> Sent: Wednesday, September 11, 2019 7:38 PM
> To: KY Srinivasan <kys@microsoft.com>; Haiyang Zhang
> <haiyangz@microsoft.com>; Stephen Hemminger
> <sthemmin@microsoft.com>; sashal@kernel.org; davem@davemloft.net;
> linux-hyperv@vger.kernel.org; netdev@vger.kernel.org; linux-
> kernel@vger.kernel.org; Michael Kelley <mikelley@microsoft.com>
> Cc: Dexuan Cui <decui@microsoft.com>
> Subject: [PATCH][PATCH net-next] hv_netvsc: Add the support of hibernation
> 
> The existing netvsc_detach() and netvsc_attach() APIs make it easy to
> implement the suspend/resume callbacks.
> 
> Signed-off-by: Dexuan Cui <decui@microsoft.com>
> ---
> 
> This patch is basically a pure Hyper-V specific change and it has a
> build dependency on the commit 271b2224d42f ("Drivers: hv: vmbus:
> Implement
> suspend/resume for VSC drivers for hibernation"), which is on Sasha Levin's
> Hyper-V tree's hyperv-next branch:
> https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.k
> ernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Fhyperv%2Flinux.git%2
> Flog%2F%3Fh%3Dhyperv-
> next&amp;data=02%7C01%7Chaiyangz%40microsoft.com%7C0b84e40c446
> 648cc35fb08d737110e28%7C72f988bf86f141af91ab2d7cd011db47%7C1%7
> C0%7C637038418703112019&amp;sdata=qd7DGFCJZ%2BDTix0VGcCe1JucV
> O97E0gILpVpcxlA6EE%3D&amp;reserved=0
> 
> I request this patch should go through Sasha's tree rather than the
> net-next tree.
> 
>  drivers/net/hyperv/hyperv_net.h |  3 +++
>  drivers/net/hyperv/netvsc_drv.c | 59
> +++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 62 insertions(+)
> 
> diff --git a/drivers/net/hyperv/hyperv_net.h
> b/drivers/net/hyperv/hyperv_net.h
> index ecc9af0..b8763ee 100644
> --- a/drivers/net/hyperv/hyperv_net.h
> +++ b/drivers/net/hyperv/hyperv_net.h
> @@ -952,6 +952,9 @@ struct net_device_context {
>  	u32 vf_alloc;
>  	/* Serial number of the VF to team with */
>  	u32 vf_serial;
> +
> +	/* Used to temporarily save the config info across hibernation */
> +	struct netvsc_device_info *saved_netvsc_dev_info;
>  };
> 
>  /* Per channel data */
> diff --git a/drivers/net/hyperv/netvsc_drv.c
> b/drivers/net/hyperv/netvsc_drv.c
> index afdcc56..f920959 100644
> --- a/drivers/net/hyperv/netvsc_drv.c
> +++ b/drivers/net/hyperv/netvsc_drv.c
> @@ -2392,6 +2392,63 @@ static int netvsc_remove(struct hv_device *dev)
>  	return 0;
>  }
> 
> +static int netvsc_suspend(struct hv_device *dev)
> +{
> +	struct net_device_context *ndev_ctx;
> +	struct net_device *vf_netdev, *net;
> +	struct netvsc_device *nvdev;
> +	int ret;
> +
> +	net = hv_get_drvdata(dev);
> +
> +	ndev_ctx = netdev_priv(net);
> +	cancel_delayed_work_sync(&ndev_ctx->dwork);
> +
> +	rtnl_lock();
> +
> +	nvdev = rtnl_dereference(ndev_ctx->nvdev);
> +	if (nvdev == NULL) {
> +		ret = -ENODEV;
> +		goto out;
> +	}
> +
> +	cancel_work_sync(&nvdev->subchan_work);

This looks redundant because netvsc_detach() cancels subchan_work.

Thanks,
- Haiyang