[PATCH RFC 2/2] net: Hack to enable skb list receive in the napi layer.

[Steffen Klassert <steffen.klassert@secunet.com>]

This patch was used to test patch ("net: Support flow sorted skb lists
for IPv4.") It is just a hack that disables GRO and does skb list
receive instead. Not for merging!

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
 include/linux/netdevice.h |  5 ++++-
 net/core/dev.c            | 23 ++++++++++++++---------
 net/ipv4/ip_input.c       |  1 +
 3 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index e2b3bd750c98..6518ceeda05d 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -333,7 +333,10 @@ struct napi_struct {
 	int			poll_owner;
 #endif
 	struct net_device	*dev;
-	struct gro_list		gro_hash[GRO_HASH_BUCKETS];
+	union {
+		struct list_head	rx_list;
+		struct gro_list		gro_hash[GRO_HASH_BUCKETS];
+	};
 	struct sk_buff		*skb;
 	struct hrtimer		timer;
 	struct list_head	dev_list;
diff --git a/net/core/dev.c b/net/core/dev.c
index 147da35d7380..68e00727c657 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5470,6 +5470,10 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
 	int same_flow;
 	int grow;
 
+	list_add_tail(&skb->list, &napi->rx_list);
+	ret = GRO_CONSUMED;
+	goto out;
+
 	if (netif_elide_gro(skb->dev))
 		goto normal;
 
@@ -5559,7 +5563,7 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
 	} else if (test_bit(hash, &napi->gro_bitmask)) {
 		__clear_bit(hash, &napi->gro_bitmask);
 	}
-
+out:
 	return ret;
 
 normal:
@@ -5958,7 +5962,7 @@ bool napi_complete_done(struct napi_struct *n, int work_done)
 				 NAPIF_STATE_IN_BUSY_POLL)))
 		return false;
 
-	if (n->gro_bitmask) {
+	if (!list_empty(&n->rx_list)) {
 		unsigned long timeout = 0;
 
 		if (work_done)
@@ -5967,8 +5971,10 @@ bool napi_complete_done(struct napi_struct *n, int work_done)
 		if (timeout)
 			hrtimer_start(&n->timer, ns_to_ktime(timeout),
 				      HRTIMER_MODE_REL_PINNED);
-		else
-			napi_gro_flush(n, false);
+		else {
+			netif_receive_skb_list(&n->rx_list);
+			INIT_LIST_HEAD(&n->rx_list);
+		}
 	}
 	if (unlikely(!list_empty(&n->poll_list))) {
 		/* If n->poll_list is not empty, we need to mask irqs */
@@ -6189,6 +6195,7 @@ void netif_napi_add(struct net_device *dev, struct napi_struct *napi,
 		    int (*poll)(struct napi_struct *, int), int weight)
 {
 	INIT_LIST_HEAD(&napi->poll_list);
+	INIT_LIST_HEAD(&napi->rx_list);
 	hrtimer_init(&napi->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_PINNED);
 	napi->timer.function = napi_watchdog;
 	init_gro_hash(napi);
@@ -6289,11 +6296,9 @@ static int napi_poll(struct napi_struct *n, struct list_head *repoll)
 		goto out_unlock;
 	}
 
-	if (n->gro_bitmask) {
-		/* flush too old packets
-		 * If HZ < 1000, flush all packets.
-		 */
-		napi_gro_flush(n, HZ >= 1000);
+	if (!list_empty(&n->rx_list)) {
+		netif_receive_skb_list(&n->rx_list);
+		INIT_LIST_HEAD(&n->rx_list);
 	}
 
 	/* Some drivers may have called napi_schedule
diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index bf710bf95fea..847965f83a2f 100644
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -729,6 +729,7 @@ void ip_list_rcv(struct list_head *head, struct packet_type *pt,
 		}
 		list_add_tail(&skb->list, &sublist);
 	}
+
 	/* dispatch final sublist */
 	ip_sublist_rcv(&sublist, curr_dev, curr_net);
 }
-- 
2.17.1