[PATCH v2] packet: uses kfree_skb() for drops or errors.

[Weongyo Jeong]

consume_skb() isn't for drop or error cases that  kfree_skb() is more proper
one.  At this patch, it fixed tpacket_rcv() and packet_rcv() to be
consistent for error or non-error cases letting perf trace its event
properly.

Signed-off-by: Weongyo Jeong <weongyo.li...@gmail.com>
---
 net/packet/af_packet.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 1ecfa71..cd100cf 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2040,7 +2040,7 @@ static int packet_rcv(struct sk_buff *skb, struct 
net_device *dev,
        struct sockaddr_ll *sll;
        struct packet_sock *po;
        u8 *skb_head = skb->data;
-       int skb_len = skb->len;
+       int err = 0, skb_len = skb->len;
        unsigned int snaplen, res;
 
        if (skb->pkt_type == PACKET_LOOPBACK)
@@ -2130,6 +2130,7 @@ static int packet_rcv(struct sk_buff *skb, struct 
net_device *dev,
        return 0;
 
 drop_n_acct:
+       err = -1;
        spin_lock(&sk->sk_receive_queue.lock);
        po->stats.stats1.tp_drops++;
        atomic_inc(&sk->sk_drops);
@@ -2141,7 +2142,10 @@ drop_n_restore:
                skb->len = skb_len;
        }
 drop:
-       consume_skb(skb);
+       if (!err)
+               consume_skb(skb);
+       else
+               kfree_skb(skb);
        return 0;
 }
 
@@ -2153,7 +2157,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct 
net_device *dev,
        struct sockaddr_ll *sll;
        union tpacket_uhdr h;
        u8 *skb_head = skb->data;
-       int skb_len = skb->len;
+       int err = 0, skb_len = skb->len;
        unsigned int snaplen, res;
        unsigned long status = TP_STATUS_USER;
        unsigned short macoff, netoff, hdrlen;
@@ -2367,10 +2371,14 @@ drop_n_restore:
                skb->len = skb_len;
        }
 drop:
-       kfree_skb(skb);
+       if (!err)
+               consume_skb(skb);
+       else
+               kfree_skb(skb);
        return 0;
 
 drop_n_account:
+       err = -1;
        po->stats.stats1.tp_drops++;
        spin_unlock(&sk->sk_receive_queue.lock);
 
-- 
2.1.3