Merge branch 'xdp-adjust-xdp-redirect-tracepoint'

Jesper Dangaard Brouer says:

====================
xdp: adjust xdp redirect tracepoint

Working on streamlining the tracepoints for XDP.  The eBPF programs
and XDP have no flow-control or queueing.  Investigating using
tracepoint to provide a feedback on XDP_REDIRECT xmit overflow events.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/intel/ixgbe/ixgbe_main.c

@@ -9860,7 +9860,7 @@ static int ixgbe_xdp_xmit(struct net_device *dev, struct xdp_buff *xdp)
 
 	err = ixgbe_xmit_xdp_ring(adapter, xdp);
 	if (err != IXGBE_XDP_TX)
-		return -ENOMEM;
+		return -ENOSPC;
 
 	return 0;
 }

include/trace/events/xdp.h

@@ -53,15 +53,16 @@ TRACE_EVENT(xdp_redirect,
 
 	TP_PROTO(const struct net_device *from,
 		 const struct net_device *to,
-		 const struct bpf_prog *xdp, u32 act),
+		 const struct bpf_prog *xdp, u32 act, int err),
 
-	TP_ARGS(from, to, xdp, act),
+	TP_ARGS(from, to, xdp, act, err),
 
 	TP_STRUCT__entry(
 		__string(name_from, from->name)
 		__string(name_to, to->name)
 		__array(u8, prog_tag, 8)
 		__field(u32, act)
+		__field(int, err)
 	),
 
 	TP_fast_assign(
@@ -70,12 +71,14 @@ TRACE_EVENT(xdp_redirect,
 		__assign_str(name_from, from->name);
 		__assign_str(name_to, to->name);
 		__entry->act = act;
+		__entry->err = err;
 	),
 
-	TP_printk("prog=%s from=%s to=%s action=%s",
+	TP_printk("prog=%s from=%s to=%s action=%s err=%d",
 		  __print_hex_str(__entry->prog_tag, 8),
 		  __get_str(name_from), __get_str(name_to),
-		  __print_symbolic(__entry->act, __XDP_ACT_SYM_TAB))
+		  __print_symbolic(__entry->act, __XDP_ACT_SYM_TAB),
+		  __entry->err)
 );
 #endif /* _TRACE_XDP_H */
 

net/core/filter.c

@@ -2535,14 +2535,16 @@ int xdp_do_redirect_map(struct net_device *dev, struct xdp_buff *xdp,
 	struct bpf_map *map = ri->map;
 	u32 index = ri->ifindex;
 	struct net_device *fwd;
-	int err = -EINVAL;
+	int err;
 
 	ri->ifindex = 0;
 	ri->map = NULL;
 
 	fwd = __dev_map_lookup_elem(map, index);
-	if (!fwd)
+	if (!fwd) {
+		err = -EINVAL;
 		goto out;
+	}
 
 	if (ri->map_to_flush && (ri->map_to_flush != map))
 		xdp_do_flush_map();
@@ -2552,7 +2554,7 @@ int xdp_do_redirect_map(struct net_device *dev, struct xdp_buff *xdp,
 		ri->map_to_flush = map;
 
 out:
-	trace_xdp_redirect(dev, fwd, xdp_prog, XDP_REDIRECT);
+	trace_xdp_redirect(dev, fwd, xdp_prog, XDP_REDIRECT, err);
 	return err;
 }
 
@@ -2562,6 +2564,7 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp,
 	struct redirect_info *ri = this_cpu_ptr(&redirect_info);
 	struct net_device *fwd;
 	u32 index = ri->ifindex;
+	int err;
 
 	if (ri->map)
 		return xdp_do_redirect_map(dev, xdp, xdp_prog);
@@ -2570,12 +2573,14 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp,
 	ri->ifindex = 0;
 	if (unlikely(!fwd)) {
 		bpf_warn_invalid_xdp_redirect(index);
-		return -EINVAL;
+		err = -EINVAL;
+		goto out;
 	}
 
-	trace_xdp_redirect(dev, fwd, xdp_prog, XDP_REDIRECT);
-
-	return __bpf_tx_xdp(fwd, NULL, xdp, 0);
+	err = __bpf_tx_xdp(fwd, NULL, xdp, 0);
+out:
+	trace_xdp_redirect(dev, fwd, xdp_prog, XDP_REDIRECT, err);
+	return err;
 }
 EXPORT_SYMBOL_GPL(xdp_do_redirect);