[PATCH v2 net-next 4/4] net/core: handle GRO_NORMAL skbs as a list in napi_gro_receive_list

[Edward Cree]

Allows GRO-using drivers to get the benefits of batching for non-GROable
 traffic.

Signed-off-by: Edward Cree <ec...@solarflare.com>
---
 net/core/dev.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 69e2819994e4..9a937d2ac83b 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5617,6 +5617,7 @@ EXPORT_SYMBOL(napi_gro_receive);
 int napi_gro_receive_list(struct napi_struct *napi, struct list_head *head)
 {
        struct sk_buff *skb, *next;
+       struct list_head sublist;
        gro_result_t result;
        int kept = 0;
 
@@ -5626,14 +5627,26 @@ int napi_gro_receive_list(struct napi_struct *napi, 
struct list_head *head)
                skb_gro_reset_offset(skb);
        }
 
+       INIT_LIST_HEAD(&sublist);
        list_for_each_entry_safe(skb, next, head, list) {
                list_del(&skb->list);
                skb->next = NULL;
                result = dev_gro_receive(napi, skb);
-               result = napi_skb_finish(result, skb);
-               if (result != GRO_DROP)
-                       kept++;
+               if (result == GRO_NORMAL) {
+                       list_add_tail(&skb->list, &sublist);
+                       continue;
+               } else {
+                       if (!list_empty(&sublist)) {
+                               /* Handle the GRO_NORMAL skbs to prevent OoO */
+                               kept += 
netif_receive_skb_list_internal(&sublist);
+                               INIT_LIST_HEAD(&sublist);
+                       }
+                       result = napi_skb_finish(result, skb);
+                       if (result != GRO_DROP)
+                               kept++;
+               }
        }
+       kept += netif_receive_skb_list_internal(&sublist);
        return kept;
 }
 EXPORT_SYMBOL(napi_gro_receive_list);