[PATCH RFC net-next 20/20] net: core: add (unlikely) DSA support in napi_gro_frags()

[Alexander Lobakin]

Make napi_gro_frags() available for DSA-enabled device drivers by adding
the same condition for them as the one in eth_type_trans().

Signed-off-by: Alexander Lobakin <alobakin@xxxxxxxx>
---
 net/core/dev.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index f1b8afcfbc0f..923b930a4506 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -142,6 +142,7 @@
 #include <linux/net_namespace.h>
 #include <linux/indirect_call_wrapper.h>
 #include <net/devlink.h>
+#include <net/dsa.h>
 
 #include "net-sysfs.h"
 
@@ -5951,6 +5952,7 @@ static gro_result_t napi_frags_finish(struct napi_struct *napi,
  */
 static struct sk_buff *napi_frags_skb(struct napi_struct *napi)
 {
+	struct net_device *dev = napi->dev;
 	struct sk_buff *skb = napi->skb;
 	const struct ethhdr *eth;
 	unsigned int hlen = sizeof(*eth);
@@ -5964,7 +5966,7 @@ static struct sk_buff *napi_frags_skb(struct napi_struct *napi)
 		eth = skb_gro_header_slow(skb, hlen, 0);
 		if (unlikely(!eth)) {
 			net_warn_ratelimited("%s: dropping impossible skb from %s\n",
-					     __func__, napi->dev->name);
+					     __func__, dev->name);
 			napi_reuse_skb(napi, skb);
 			return NULL;
 		}
@@ -5978,10 +5980,13 @@ static struct sk_buff *napi_frags_skb(struct napi_struct *napi)
 
 	/*
 	 * This works because the only protocols we care about don't require
-	 * special handling.
+	 * special handling... except for DSA.
 	 * We'll fix it up properly in napi_frags_finish()
 	 */
-	skb->protocol = eth->h_proto;
+	if (unlikely(netdev_uses_dsa(dev)) && dsa_can_decode(skb, dev))
+		skb->protocol = htons(ETH_P_XDSA);
+	else
+		skb->protocol = eth->h_proto;
 
 	return skb;
 }
-- 
2.24.1