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Date:   Fri, 16 Apr 2021 09:40:06 -0700
From:   Stephen Hemminger <stephen@networkplumber.org>
To:     Dexuan Cui <decui@microsoft.com>
Cc:     davem@davemloft.net, kuba@kernel.org, kys@microsoft.com,
        haiyangz@microsoft.com, sthemmin@microsoft.com, wei.liu@kernel.org,
        liuwe@microsoft.com, netdev@vger.kernel.org, leon@kernel.org,
        andrew@lunn.ch, bernd@petrovitsch.priv.at, rdunlap@infradead.org,
        shacharr@microsoft.com, linux-kernel@vger.kernel.org,
        linux-hyperv@vger.kernel.org
Subject: Re: [PATCH v7 net-next] net: mana: Add a driver for Microsoft Azure
 Network Adapter (MANA)
Message-ID: <20210416094006.70661f47@hermes.local>
In-Reply-To: <20210416060705.21998-1-decui@microsoft.com>
References: <20210416060705.21998-1-decui@microsoft.com>
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On Thu, 15 Apr 2021 23:07:05 -0700
Dexuan Cui <decui@microsoft.com> wrote:

> diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
> index 7349a70af083..f682a5572d84 100644
> --- a/drivers/net/hyperv/netvsc_drv.c
> +++ b/drivers/net/hyperv/netvsc_drv.c
> @@ -2297,6 +2297,7 @@ static struct net_device *get_netvsc_byslot(const struct net_device *vf_netdev)
>  {
>  	struct device *parent = vf_netdev->dev.parent;
>  	struct net_device_context *ndev_ctx;
> +	struct net_device *ndev;
>  	struct pci_dev *pdev;
>  	u32 serial;
>  
> @@ -2319,8 +2320,17 @@ static struct net_device *get_netvsc_byslot(const struct net_device *vf_netdev)
>  		if (!ndev_ctx->vf_alloc)
>  			continue;
>  
> -		if (ndev_ctx->vf_serial == serial)
> -			return hv_get_drvdata(ndev_ctx->device_ctx);
> +		if (ndev_ctx->vf_serial != serial)
> +			continue;
> +
> +		ndev = hv_get_drvdata(ndev_ctx->device_ctx);
> +		if (ndev->addr_len != vf_netdev->addr_len ||
> +		    memcmp(ndev->perm_addr, vf_netdev->perm_addr,
> +			   ndev->addr_len) != 0)
> +			continue;
> +
> +		return ndev;
> +
>  	}
>  
>  	netdev_notice(vf_netdev,


This probably should be a separate patch.
I think it is trying to address the case of VF discovery in Hyper-V/Azure where the reported
VF from Hypervisor is bogus or confused.