diff mbox series

[net-next,v4,1/4] net: dsa: add support for DSA rx offloading via metadata dst

Message ID 20221114124214.58199-2-nbd@nbd.name
State New
Headers
Series [net-next,v4,1/4] net: dsa: add support for DSA rx offloading via metadata dst |

Commit Message

Felix Fietkau Nov. 14, 2022, 12:42 p.m. UTC 
  If a metadata dst is present with the type METADATA_HW_PORT_MUX on a dsa cpu
port netdev, assume that it carries the port number and that there is no DSA
tag present in the skb data.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 net/core/flow_dissector.c |  4 +++-
 net/dsa/dsa.c             | 19 ++++++++++++++++++-
 2 files changed, 21 insertions(+), 2 deletions(-)

Comments

Vladimir Oltean Nov. 14, 2022, 4:59 p.m. UTC | #1 
On Mon, Nov 14, 2022 at 01:42:11PM +0100, Felix Fietkau wrote:
> If a metadata dst is present with the type METADATA_HW_PORT_MUX on a dsa cpu
> port netdev, assume that it carries the port number and that there is no DSA
> tag present in the skb data.
> 
> Signed-off-by: Felix Fietkau <nbd@nbd.name>
> ---

Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Florian Fainelli Nov. 14, 2022, 5:59 p.m. UTC | #2 
On 11/14/22 04:42, Felix Fietkau wrote:
> If a metadata dst is present with the type METADATA_HW_PORT_MUX on a dsa cpu
> port netdev, assume that it carries the port number and that there is no DSA
> tag present in the skb data.
> 
> Signed-off-by: Felix Fietkau <nbd@nbd.name>

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>

Is the plan to use the lwoer bits of the 32-bit port_id as the port 
number for now, and we can use the remaining 24 or so bits for passing 
classification (reason why we forward the packet, QoS etc. ) information 
in the future?

Might be time for me to revive the systemport patches supporting 
Broadcom tags in the the DMA descriptor.

Thanks!
Vladimir Oltean Nov. 14, 2022, 6:19 p.m. UTC | #3 
On Mon, Nov 14, 2022 at 09:59:09AM -0800, Florian Fainelli wrote:
> On 11/14/22 04:42, Felix Fietkau wrote:
> > If a metadata dst is present with the type METADATA_HW_PORT_MUX on a dsa cpu
> > port netdev, assume that it carries the port number and that there is no DSA
> > tag present in the skb data.
> > 
> > Signed-off-by: Felix Fietkau <nbd@nbd.name>
> 
> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
> 
> Is the plan to use the lwoer bits of the 32-bit port_id as the port number
> for now, and we can use the remaining 24 or so bits for passing
> classification (reason why we forward the packet, QoS etc. ) information in
> the future?
> 
> Might be time for me to revive the systemport patches supporting Broadcom
> tags in the the DMA descriptor.

It's not really clear how to expand the HW_PORT_MUX model to provide QoS
info and trap reason, without switching to per-packet allocation, which
is what Jakub seemingly wanted to avoid with skb extensions (among other
more minor things).

https://patchwork.kernel.org/project/netdevbpf/patch/20221104174151.439008-4-maxime.chevallier@bootlin.com/#25078661

Felix didn't present a need for more than the port id either, so this is
why we have what we have right now.
diff mbox series

Patch

diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 25cd35f5922e..3e81798ed3e0 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -971,12 +971,14 @@  bool __skb_flow_dissect(const struct net *net,
 #if IS_ENABLED(CONFIG_NET_DSA)
 		if (unlikely(skb->dev && netdev_uses_dsa(skb->dev) &&
 			     proto == htons(ETH_P_XDSA))) {
+			struct metadata_dst *md_dst = skb_metadata_dst(skb);
 			const struct dsa_device_ops *ops;
 			int offset = 0;
 
 			ops = skb->dev->dsa_ptr->tag_ops;
 			/* Only DSA header taggers break flow dissection */
-			if (ops->needed_headroom) {
+			if (ops->needed_headroom &&
+			    (!md_dst || md_dst->type != METADATA_HW_PORT_MUX)) {
 				if (ops->flow_dissect)
 					ops->flow_dissect(skb, &proto, &offset);
 				else
diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
index 64b14f655b23..6caf2ec648fd 100644
--- a/net/dsa/dsa.c
+++ b/net/dsa/dsa.c
@@ -11,6 +11,7 @@ 
 #include <linux/netdevice.h>
 #include <linux/sysfs.h>
 #include <linux/ptp_classify.h>
+#include <net/dst_metadata.h>
 
 #include "dsa_priv.h"
 
@@ -216,6 +217,7 @@  static bool dsa_skb_defer_rx_timestamp(struct dsa_slave_priv *p,
 static int dsa_switch_rcv(struct sk_buff *skb, struct net_device *dev,
 			  struct packet_type *pt, struct net_device *unused)
 {
+	struct metadata_dst *md_dst = skb_metadata_dst(skb);
 	struct dsa_port *cpu_dp = dev->dsa_ptr;
 	struct sk_buff *nskb = NULL;
 	struct dsa_slave_priv *p;
@@ -229,7 +231,22 @@  static int dsa_switch_rcv(struct sk_buff *skb, struct net_device *dev,
 	if (!skb)
 		return 0;
 
-	nskb = cpu_dp->rcv(skb, dev);
+	if (md_dst && md_dst->type == METADATA_HW_PORT_MUX) {
+		unsigned int port = md_dst->u.port_info.port_id;
+
+		skb_dst_drop(skb);
+		if (!skb_has_extensions(skb))
+			skb->slow_gro = 0;
+
+		skb->dev = dsa_master_find_slave(dev, 0, port);
+		if (likely(skb->dev)) {
+			dsa_default_offload_fwd_mark(skb);
+			nskb = skb;
+		}
+	} else {
+		nskb = cpu_dp->rcv(skb, dev);
+	}
+
 	if (!nskb) {
 		kfree_skb(skb);
 		return 0;