gro: avoid checking for a failed search

[ Upstream commit e081ecf084d31809242fb0b9f35484d5fb3a161a ]

After searching for a protocol handler in dev_gro_receive, checking for
failure is redundant. Skip the failure code after finding the
corresponding handler.

Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Richard Gobert <richardbgobert@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20221108123320.GA59373@debian
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Stable-dep-of: 7871f54e3dee ("gro: take care of DODGY packets")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/core/gro.c b/net/core/gro.c
index bc94517..8e0fe85 100644 (file)
--- a/net/core/gro.c
+++ b/net/core/gro.c
@@ -489,45 +489,45 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
 
        rcu_read_lock();
        list_for_each_entry_rcu(ptype, head, list) {
-               if (ptype->type != type || !ptype->callbacks.gro_receive)
-                       continue;
-
-               skb_set_network_header(skb, skb_gro_offset(skb));
-               skb_reset_mac_len(skb);
-               BUILD_BUG_ON(sizeof_field(struct napi_gro_cb, zeroed) != sizeof(u32));
-               BUILD_BUG_ON(!IS_ALIGNED(offsetof(struct napi_gro_cb, zeroed),
-                                        sizeof(u32))); /* Avoid slow unaligned acc */
-               *(u32 *)&NAPI_GRO_CB(skb)->zeroed = 0;
-               NAPI_GRO_CB(skb)->flush = skb_has_frag_list(skb);
-               NAPI_GRO_CB(skb)->is_atomic = 1;
-               NAPI_GRO_CB(skb)->count = 1;
-               if (unlikely(skb_is_gso(skb))) {
-                       NAPI_GRO_CB(skb)->count = skb_shinfo(skb)->gso_segs;
-                       /* Only support TCP at the moment. */
-                       if (!skb_is_gso_tcp(skb))
-                               NAPI_GRO_CB(skb)->flush = 1;
-               }
-
-               /* Setup for GRO checksum validation */
-               switch (skb->ip_summed) {
-               case CHECKSUM_COMPLETE:
-                       NAPI_GRO_CB(skb)->csum = skb->csum;
-                       NAPI_GRO_CB(skb)->csum_valid = 1;
-                       break;
-               case CHECKSUM_UNNECESSARY:
-                       NAPI_GRO_CB(skb)->csum_cnt = skb->csum_level + 1;
-                       break;
-               }
+               if (ptype->type == type && ptype->callbacks.gro_receive)
+                       goto found_ptype;
+       }
+       rcu_read_unlock();
+       goto normal;
+
+found_ptype:
+       skb_set_network_header(skb, skb_gro_offset(skb));
+       skb_reset_mac_len(skb);
+       BUILD_BUG_ON(sizeof_field(struct napi_gro_cb, zeroed) != sizeof(u32));
+       BUILD_BUG_ON(!IS_ALIGNED(offsetof(struct napi_gro_cb, zeroed),
+                                       sizeof(u32))); /* Avoid slow unaligned acc */
+       *(u32 *)&NAPI_GRO_CB(skb)->zeroed = 0;
+       NAPI_GRO_CB(skb)->flush = skb_has_frag_list(skb);
+       NAPI_GRO_CB(skb)->is_atomic = 1;
+       NAPI_GRO_CB(skb)->count = 1;
+       if (unlikely(skb_is_gso(skb))) {
+               NAPI_GRO_CB(skb)->count = skb_shinfo(skb)->gso_segs;
+               /* Only support TCP at the moment. */
+               if (!skb_is_gso_tcp(skb))
+                       NAPI_GRO_CB(skb)->flush = 1;
+       }
 
-               pp = INDIRECT_CALL_INET(ptype->callbacks.gro_receive,
-                                       ipv6_gro_receive, inet_gro_receive,
-                                       &gro_list->list, skb);
+       /* Setup for GRO checksum validation */
+       switch (skb->ip_summed) {
+       case CHECKSUM_COMPLETE:
+               NAPI_GRO_CB(skb)->csum = skb->csum;
+               NAPI_GRO_CB(skb)->csum_valid = 1;
+               break;
+       case CHECKSUM_UNNECESSARY:
+               NAPI_GRO_CB(skb)->csum_cnt = skb->csum_level + 1;
                break;
        }
-       rcu_read_unlock();
 
-       if (&ptype->list == head)
-               goto normal;
+       pp = INDIRECT_CALL_INET(ptype->callbacks.gro_receive,
+                               ipv6_gro_receive, inet_gro_receive,
+                               &gro_list->list, skb);
+
+       rcu_read_unlock();
 
        if (PTR_ERR(pp) == -EINPROGRESS) {
                ret = GRO_CONSUMED;