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From: subashab@codeaurora.org
To: Loic Poulain <loic.poulain@linaro.org>
Cc: stranche@codeaurora.org, netdev@vger.kernel.org, kuba@kernel.org
Subject: Re: [PATCH] net: rmnet: Adjust virtual device MTU on real device capability
Date: Fri, 04 Dec 2020 14:56:22 -0700	[thread overview]
Message-ID: <3a2ca2c269911de71df6dca2e981f7fe@codeaurora.org> (raw)
In-Reply-To: <1607017240-10582-1-git-send-email-loic.poulain@linaro.org>

On 2020-12-03 10:40, Loic Poulain wrote:
> A submitted qmap/rmnet packet size can not be larger than the linked
> interface (real_dev) MTU. This patch ensures that the rmnet virtual
> iface MTU is configured according real device capability.
> 
> Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
> ---
>  drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
> b/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
> index d58b51d..d1d7328 100644
> --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
> +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
> @@ -60,9 +60,14 @@ static netdev_tx_t rmnet_vnd_start_xmit(struct 
> sk_buff
> *skb,
> 
>  static int rmnet_vnd_change_mtu(struct net_device *rmnet_dev, int
> new_mtu)
>  {
> +	struct rmnet_priv *priv = netdev_priv(rmnet_dev);
> +
>  	if (new_mtu < 0 || new_mtu > RMNET_MAX_PACKET_SIZE)
>  		return -EINVAL;
> 
> +	if (priv->real_dev && (new_mtu + RMNET_NEEDED_HEADROOM) >
> priv->real_dev->mtu)
> +		return -EINVAL;
> +
>  	rmnet_dev->mtu = new_mtu;
>  	return 0;
>  }
> @@ -242,6 +247,9 @@ int rmnet_vnd_newlink(u8 id, struct net_device
> *rmnet_dev,
> 
>  	priv->real_dev = real_dev;
> 
> +	/* Align default MTU with real_dev MTU */
> +	rmnet_vnd_change_mtu(rmnet_dev, real_dev->mtu -
> RMNET_NEEDED_HEADROOM);
> +
>  	rc = register_netdevice(rmnet_dev);
>  	if (!rc) {
>  		ep->egress_dev = rmnet_dev;

This would need similar checks in the NETDEV_PRECHANGEMTU
netdev notifier.

  reply	other threads:[~2020-12-04 21:57 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-03 17:40 [PATCH] net: rmnet: Adjust virtual device MTU on real device capability Loic Poulain
2020-12-04 21:56 ` subashab [this message]
2020-12-07 16:45   ` Loic Poulain
2020-12-07 20:16     ` Jakub Kicinski
2020-12-08  8:19       ` subashab
2020-12-08 14:50         ` Loic Poulain

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