# \[PATCH 1/2\] af\_packet: make tpacket\_rcv to not set status value before run\_filter

- From: Alexander Drozdov \<hidden\>
- Date: 2015-03-19 08:02:21 
- List: netdev
- Page: https://ratatoskr.run/netdev/2015/03/4454598
- Thread: https://ratatoskr.run/netdev/2015/03/4454598/t.md

```text
It is just an optimization. We don't need the value of status variable
if the packet is filtered.

Signed-off-by: Alexander Drozdov <redacted>
---
 net/packet/af_packet.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index f8db706..6ecf8dd 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1910,14 +1910,15 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
 		}
 	}
 
-	if (skb->ip_summed == CHECKSUM_PARTIAL)
-		status |= TP_STATUS_CSUMNOTREADY;
-
 	snaplen = skb->len;
 
 	res = run_filter(skb, sk, snaplen);
 	if (!res)
 		goto drop_n_restore;
+
+	if (skb->ip_summed == CHECKSUM_PARTIAL)
+		status |= TP_STATUS_CSUMNOTREADY;
+
 	if (snaplen > res)
 		snaplen = res;
 
-- 
1.9.1
```