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Date:   Sat, 27 Aug 2022 20:54:22 +0200
From:   Andrew Lunn <andrew@lunn.ch>
To:     Maxime Chevallier <maxime.chevallier@bootlin.com>
Cc:     davem@davemloft.net, Rob Herring <robh+dt@kernel.org>,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org, thomas.petazzoni@bootlin.com,
        Florian Fainelli <f.fainelli@gmail.com>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Russell King <linux@armlinux.org.uk>,
        linux-arm-kernel@lists.infradead.org,
        Vladimir Oltean <vladimir.oltean@nxp.com>,
        Luka Perkov <luka.perkov@sartura.hr>,
        Robert Marko <robert.marko@sartura.hr>
Subject: Re: [PATCH net-next v3 2/5] net: dsa: add out-of-band tagging
 protocol
Message-ID: <YwpoXpcRickYzD9K@lunn.ch>
References: <20220826154650.615582-1-maxime.chevallier@bootlin.com>
 <20220826154650.615582-3-maxime.chevallier@bootlin.com>
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Precedence: bulk

> +struct dsa_oob_tag_info {
> +	u16 proto;
> +	u16 dp;
> +};

> +#define DSA_OOB_TAG_LEN 4
> +
> +int dsa_oob_tag_push(struct sk_buff *skb, struct dsa_oob_tag_info *ti)
> +{
> +	struct dsa_oob_tag_info *tag_info;
> +
> +	tag_info = (struct dsa_oob_tag_info *)skb->head;
> +
> +	tag_info->proto = ti->proto;
> +	tag_info->dp = ti->dp;

Do you need to be worried about alignment here? Is skb->head
guaranteed to be at least 16 bit aligned? I think you would be safer
to use get_unaligned_le16(val, tag);

	Andrew