Re: [PATCH net-next v2 2/7] dpaa_eth: add basic XDP support

From: Jakub Kicinski <kuba@kernel.org>
To: Camelia Groza <camelia.groza@nxp.com>
Cc: brouer@redhat.com, saeed@kernel.org, davem@davemloft.net,
	madalin.bucur@oss.nxp.com, ioana.ciornei@nxp.com,
	netdev@vger.kernel.org
Subject: Re: [PATCH net-next v2 2/7] dpaa_eth: add basic XDP support
Date: Wed, 18 Nov 2020 16:21:37 -0800	[thread overview]
Message-ID: <20201118162137.149625e3@kicinski-fedora-PC1C0HJN.hsd1.ca.comcast.net> (raw)
In-Reply-To: <e8f6ede91ab1c3fa50953076e7983979de04d2b5.1605535745.git.camelia.groza@nxp.com>

On Mon, 16 Nov 2020 16:42:28 +0200 Camelia Groza wrote:
> +	if (likely(fd_format == qm_fd_contig)) {
> +		xdp_act = dpaa_run_xdp(priv, (struct qm_fd *)fd, vaddr,
> +				       &xdp_meta_len);
> +		if (xdp_act != XDP_PASS) {
> +			percpu_stats->rx_packets++;
> +			percpu_stats->rx_bytes += qm_fd_get_length(fd);
> +			return qman_cb_dqrr_consume;
> +		}
>  		skb = contig_fd_to_skb(priv, fd);
> -	else
> +	} else {
> +		WARN_ONCE(priv->xdp_prog, "S/G frames not supported under XDP\n");
>  		skb = sg_fd_to_skb(priv, fd);

It'd be safer to drop the packet if the format does not allow XDP 
to run. Otherwise someone can bypass whatever policy XDP is trying 
to enforce.