Re: [net-next V4 PATCH 2/5] bpf: XDP_REDIRECT enable use of cpumap

On Fri, 6 Oct 2017 13:17:48 +0200
Jesper Dangaard Brouer [off-list ref] wrote:

quoted

quoted

-int cpu_map_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_buff *xdp)
+int cpu_map_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_buff *xdp,
+		    struct net_device *dev_rx)
  {
  	struct xdp_pkt *xdp_pkt;
  	int headroom;

@@ -505,7 +506,7 @@ int cpu_map_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_buff *xdp)
  	xdp_pkt = xdp->data_hard_start;
  	xdp_pkt->data = xdp->data;
  	xdp_pkt->len  = xdp->data_end - xdp->data;
-	xdp_pkt->headroom = headroom;
+	xdp_pkt->headroom = headroom - sizeof(*xdp_pkt);    

(Just a note, bit confusing that first two patches add and extend
  this, and only in the third you add the xdp->data_meta handling,
  makes it harder to review at least.)  

Sorry.  This is a left-overs from rebasing and measuring the cost of
transferring only the pointer to the page, and remote put_page().
And your xdp->data_meta, happen basically while my patches was in-flight.

I'll move this one-line back to patch 2, to spreading over too many
patches.

I instead choose to move the creation of cpu_map_enqueue() into this
patch, but in a more simple version stating explicit that this is only
seen as a void pointer enqueue.

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer