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Date:   Wed, 16 Jun 2021 00:27:04 -0600
From:   subashab@codeaurora.org
To:     Bjorn Andersson <bjorn.andersson@linaro.org>
Cc:     Sean Tranchetti <stranche@codeaurora.org>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Alex Elder <elder@linaro.org>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next v2] net: qualcomm: rmnet: Allow partial updates
 of IFLA_FLAGS
In-Reply-To: <20210615232707.835258-1-bjorn.andersson@linaro.org>
References: <20210615232707.835258-1-bjorn.andersson@linaro.org>
Message-ID: <ad250914bbb332d408f0b42935d11149@codeaurora.org>
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On 2021-06-15 17:27, Bjorn Andersson wrote:
> The idiomatic way to handle the changelink flags/mask pair seems to be
> allow partial updates of the driver's link flags. In contrast the rmnet
> driver masks the incoming flags and then use that as the new flags.
> 
> Change the rmnet driver to follow the common scheme, before the
> introduction of IFLA_RMNET_FLAGS handling in iproute2 et al.
> 
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
> 
> Changes since v1:
> - Also do the masking dance on newlink, per Subash request
> - Add "net-next" to subject prefix
> 
>  drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c
> b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c
> index 8d51b0cb545c..27b1663c476e 100644
> --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c
> +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c
> @@ -163,7 +163,8 @@ static int rmnet_newlink(struct net *src_net,
> struct net_device *dev,
>  		struct ifla_rmnet_flags *flags;
> 
>  		flags = nla_data(data[IFLA_RMNET_FLAGS]);
> -		data_format = flags->flags & flags->mask;
> +		data_format &= ~flags->mask;
> +		data_format |= flags->flags & flags->mask;
>  	}
> 
>  	netdev_dbg(dev, "data format [0x%08X]\n", data_format);
> @@ -336,7 +337,8 @@ static int rmnet_changelink(struct net_device
> *dev, struct nlattr *tb[],
> 
>  		old_data_format = port->data_format;
>  		flags = nla_data(data[IFLA_RMNET_FLAGS]);
> -		port->data_format = flags->flags & flags->mask;
> +		port->data_format &= ~flags->mask;
> +		port->data_format |= flags->flags & flags->mask;
> 
>  		if (rmnet_vnd_update_dev_mtu(port, real_dev)) {
>  			port->data_format = old_data_format;

Reviewed-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>