can: omit unneeded skb_clone() calls

The AF_CAN core delivered always cloned sk_buffs to the AF_CAN
protocols, although this was _only_ needed by the can-raw protocol.
With this (additionally documented) change, the AF_CAN core calls the
callback functions of the registered AF_CAN protocols with the original
(uncloned) sk_buff pointer and let's the can-raw protocol do the
skb_clone() itself which omits all unneeded skb_clone() calls for other
AF_CAN protocols.

Signed-off-by: Oliver Hartkopp <oliver@hartkopp.net>
Signed-off-by: Urs Thuermann <urs.thuermann@volkswagen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 7 deletions

diff --git a/net/can/raw.c b/net/can/raw.c
index 27aab63df467..0703cba4bf9f 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -99,13 +99,14 @@ static void raw_rcv(struct sk_buff *skb, void *data)
         struct raw_sock *ro = raw_sk(sk);
         struct sockaddr_can *addr;
 
-        if (!ro->recv_own_msgs) {
-                /* check the received tx sock reference */
-                if (skb->sk == sk) {
-                        kfree_skb(skb);
-                        return;
-                }
-        }
+        /* check the received tx sock reference */
+        if (!ro->recv_own_msgs && skb->sk == sk)
+                return;
+
+        /* clone the given skb to be able to enqueue it into the rcv queue */
+        skb = skb_clone(skb, GFP_ATOMIC);
+        if (!skb)
+                return;
 
         /*
          *  Put the datagram to the queue so that raw_recvmsg() can