Re: [bpf-next V2 PATCH 06/15] tun: convert to use generic xdp_frame and xdp_return_frame API
From: Jesper Dangaard Brouer <hidden>
Date: 2018-03-08 15:16:38
Hi Jason, Please see below FIXME, which is actually a question to you. On Thu, 08 Mar 2018 14:08:11 +0100 Jesper Dangaard Brouer [off-list ref] wrote:
quoted hunk ↗ jump to hunk
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 475088f947bb..cd046cf31b77 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c
[...]
quoted hunk ↗ jump to hunk
@@ -1290,17 +1290,18 @@ static const struct net_device_ops tun_netdev_ops = { static int tun_xdp_xmit(struct net_device *dev, struct xdp_buff *xdp) { struct tun_struct *tun = netdev_priv(dev); - struct xdp_buff *buff = xdp->data_hard_start; - int headroom = xdp->data - xdp->data_hard_start; + struct xdp_frame *frame; struct tun_file *tfile; u32 numqueues; int ret = 0; - /* Assure headroom is available and buff is properly aligned */ - if (unlikely(headroom < sizeof(*xdp) || tun_is_xdp_buff(xdp))) - return -ENOSPC; + /* FIXME: Explain why this check is the needed! */ + if (unlikely(tun_is_xdp_frame(xdp))) + return -EBADRQC; - *buff = *xdp; + frame = convert_to_xdp_frame(xdp); + if (unlikely(!frame)) + return -EOVERFLOW;
To Jason, in the FIXME, I'm inheriting a check you put in, but I don't understand why this check was needed? -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer